WorldWideScience

Sample records for 3-d laser inscribing

  1. Ultrafast-laser-inscribed 3D integrated photonics: challenges and emerging applications

    Directory of Open Access Journals (Sweden)

    Gross S.

    2015-11-01

    Full Text Available Since the discovery that tightly focused femtosecond laser pulses can induce a highly localised and permanent refractive index modification in a large number of transparent dielectrics, the technique of ultrafast laser inscription has received great attention from a wide range of applications. In particular, the capability to create three-dimensional optical waveguide circuits has opened up new opportunities for integrated photonics that would not have been possible with traditional planar fabrication techniques because it enables full access to the many degrees of freedom in a photon. This paper reviews the basic techniques and technological challenges of 3D integrated photonics fabricated using ultrafast laser inscription as well as reviews the most recent progress in the fields of astrophotonics, optical communication, quantum photonics, emulation of quantum systems, optofluidics and sensing.

  2. Ultrafast laser inscribed integrated photonics: material science to device development

    Directory of Open Access Journals (Sweden)

    Gross S.

    2013-11-01

    Full Text Available Detailed studies of intense light – material interactions has led to new insights into fs laser induced refractive index change in a range of glass types. This body of knowledge enables the development of advanced processing methodologies, resulting in novel planar and 3D guided wave devices. We will review the chemistry and morphology associated with fs laser induced refractive index change in multi-component glasses such as ZBLAN, phosphates and silicates, and discuss how these material changes inform our research programs developing a range of active and passive lightwave systems.

  3. Laser Based 3D Volumetric Display System

    Science.gov (United States)

    1993-03-01

    Literature, Costa Mesa, CA July 1983. 3. "A Real Time Autostereoscopic Multiplanar 3D Display System", Rodney Don Williams, Felix Garcia, Jr., Texas...8217 .- NUMBERS LASER BASED 3D VOLUMETRIC DISPLAY SYSTEM PR: CD13 0. AUTHOR(S) PE: N/AWIU: DN303151 P. Soltan, J. Trias, W. Robinson, W. Dahlke 7...laser generated 3D volumetric images on a rotating double helix, (where the 3D displays are computer controlled for group viewing with the naked eye

  4. A femtosecond laser inscribed biochip for stem cell therapeutic applications

    Science.gov (United States)

    Choudhury, D.; Ramsay, W. T.; Brown, G.; Psaila, N. D.; Beecher, S.; Thomson, R. R.; Kiss, R.; Pells, S.; Willoughby, N. A.; Paterson, L.; Kar, A. K.

    2011-02-01

    A continuous flow microfluidic cell separation platform has been designed and fabricated using femtosecond laser inscription. The device is a scalable and non-invasive cell separation mechanism aimed at separating human embryonic stem cells from differentiated cells based on the dissimilarities in their cytoskeletal elasticity. Successful demonstration of the device has been achieved using human leukemia cells the elasticity of which is similar to that of human embryonic stem cells.

  5. Ultrafast laser inscribed fiber Bragg gratings for sensing applications

    Science.gov (United States)

    Mihailov, Stephen J.

    2016-05-01

    Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on femtosecond infrared laser-material processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This tutorial paper will present a review of some of the more recent developments.

  6. Fusion of Renewable Ring Resonator Lasers and Ultrafast Laser Inscribed Photonic Waveguides

    Science.gov (United States)

    Chandrahalim, Hengky; Rand, Stephen C.; Fan, Xudong

    2016-09-01

    We demonstrated the monolithic integration of reusable and wavelength reconfigurable ring resonator lasers and waveguides of arbitrary shapes to out-couple and guide laser emission on the same fused-silica chip. The ring resonator hosts were patterned by a single-mask standard lithography, whereas the waveguides were inscribed in the proximity of the ring resonator by using 3-dimensional femtosecond laser inscription technology. Reusability of the integrated ring resonator – waveguide system was examined by depositing, removing, and re-depositing dye-doped SU-8 solid polymer, SU-8 liquid polymer, and liquid solvent (toluene). The wavelength reconfigurability was validated by employing Rhodamine 6G (R6G) and 3,3‧-Diethyloxacarbocyanine iodide (CY3) as exemplary gain media. In all above cases, the waveguide was able to couple out and guide the laser emission. This work opens a door to reconfigurable active and passive photonic devices for on-chip coherent light sources, optical signal processing, and the investigation of new optical phenomena.

  7. Laser printing of 3D metallic interconnects

    Science.gov (United States)

    Beniam, Iyoel; Mathews, Scott A.; Charipar, Nicholas A.; Auyeung, Raymond C. Y.; Piqué, Alberto

    2016-04-01

    The use of laser-induced forward transfer (LIFT) techniques for the printing of functional materials has been demonstrated for numerous applications. The printing gives rise to patterns, which can be used to fabricate planar interconnects. More recently, various groups have demonstrated electrical interconnects from laser-printed 3D structures. The laser printing of these interconnects takes place through aggregation of voxels of either molten metal or of pastes containing dispersed metallic particles. However, the generated 3D structures do not posses the same metallic conductivity as a bulk metal interconnect of the same cross-section and length as those formed by wire bonding or tab welding. An alternative is to laser transfer entire 3D structures using a technique known as lase-and-place. Lase-and-place is a LIFT process whereby whole components and parts can be transferred from a donor substrate onto a desired location with one single laser pulse. This paper will describe the use of LIFT to laser print freestanding, solid metal foils or beams precisely over the contact pads of discrete devices to interconnect them into fully functional circuits. Furthermore, this paper will also show how the same laser can be used to bend or fold the bulk metal foils prior to transfer, thus forming compliant 3D structures able to provide strain relief for the circuits under flexing or during motion from thermal mismatch. These interconnect "ridges" can span wide gaps (on the order of a millimeter) and accommodate height differences of tens of microns between adjacent devices. Examples of these laser printed 3D metallic bridges and their role in the development of next generation electronics by additive manufacturing will be presented.

  8. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...... shutter is controlled in steps of 100 ps. Camera delay is controlled in steps of 100 ps. Each laser pulse triggers the camera delay and shutter. A 3-D image is constructed from a sequence of 50-100 2-D reflectivity images, where each frame integrates about 700 laser pulses on the CCD. In 50 Hz video mode...

  9. High accuracy 3-D laser radar

    DEFF Research Database (Denmark)

    Busck, Jens; Heiselberg, Henning

    2004-01-01

    We have developed a mono-static staring 3-D laser radar based on gated viewing with range accuracy below 1 m at 10 m and 1 cm at 100. We use a high sensitivity, fast, intensified CCD camera, and a Nd:Yag passively Q-switched 32.4 kHz pulsed green laser at 532 nm. The CCD has 752x582 pixels. Camera...

  10. Laser 3D micro-manufacturing

    Science.gov (United States)

    Piqué, Alberto; Auyeung, Raymond C. Y.; Kim, Heungsoo; Charipar, Nicholas A.; Mathews, Scott A.

    2016-06-01

    Laser-based materials processing techniques are gaining widespread use in micro-manufacturing applications. The use of laser microfabrication techniques enables the processing of micro- and nanostructures from a wide range of materials and geometries without the need for masking and etching steps commonly associated with photolithography. This review aims to describe the broad applications space covered by laser-based micro- and nanoprocessing techniques and the benefits offered by the use of lasers in micro-manufacturing processes. Given their non-lithographic nature, these processes are also referred to as laser direct-write and constitute some of the earliest demonstrations of 3D printing or additive manufacturing at the microscale. As this review will show, the use of lasers enables precise control of the various types of processing steps—from subtractive to additive—over a wide range of scales with an extensive materials palette. Overall, laser-based direct-write techniques offer multiple modes of operation including the removal (via ablative processes) and addition (via photopolymerization or printing) of most classes of materials using the same equipment in many cases. The versatility provided by these multi-function, multi-material and multi-scale laser micro-manufacturing processes cannot be matched by photolithography nor with other direct-write microfabrication techniques and offer unique opportunities for current and future 3D micro-manufacturing applications.

  11. Fabrication of back contacts using laser writer and photolithography for inscribing textured solar cells

    Indian Academy of Sciences (India)

    Murugaiya Sridar Ilango; Vijay Monterio; Sheela K Ramasesha

    2015-02-01

    Semiconductor fabrication process begins with photolithography. Preparing a photo mask is the key process step in photolithography. The photo mask was fabricated by inscribing patterns directly onto a soda lime glass with the help of a laser beam, as it is easily controllable. Laser writer LW405-A was used for preparing the mask in this study. Exposure wavelength of 405 nm was used, with which 1.2 m feature size can be written in direct write-mode over the soda lime glass plate. The advantage of using the fabricated mask is that it can be used to design back contacts for thin film Photovoltaic (PV) solar cells. To investigate the process capability of LW405-A, same pattern with different line widths was written on soda lime glass samples at different writing speeds. The pattern was inscribed without proximity effect and stitching errors, which was characterized using optical microscope and field emission scanning electron microscope (FE-SEM). It was proven that writing speed of a mask-writer is decided according to the intended feature size and line width. As the writing speed increases, the edges of the patterns become rougher due to uneven scattering of the laser beam. From the fabricated mask, the solar cell can be developed embedding both the contacts at the bottom layer, to increase the absorption of solar radiation on the top surface effectively by increasing light absorption area.

  12. Low loss depressed cladding waveguide inscribed in YAG:Nd single crystal by femtosecond laser pulses.

    Science.gov (United States)

    Okhrimchuk, Andrey; Mezentsev, Vladimir; Shestakov, Alexander; Bennion, Ian

    2012-02-13

    A depressed cladding waveguide with record low loss of 0.12 dB/cm is inscribed in YAG:Nd(0.3at.%) crystal by femtosecond laser pulses with an elliptical beam waist. The waveguide is formed by a set of parallel tracks which constitute the depressed cladding. It is a key element for compact and efficient CW waveguide laser operating at 1064 nm and pumped by a multimode laser diode. Special attention is paid to mechanical stress resulting from the inscription process. Numerical calculation of mode distribution and propagation loss with the elasto-optical effect taken into account leads to the conclusion that the depressed cladding is a dominating factor in waveguide mode formation, while the mechanical stress only slightly distorts waveguide modes.

  13. Laser scanner 3D terrestri e mobile

    Directory of Open Access Journals (Sweden)

    Mario Ciamba

    2013-08-01

    Full Text Available Recentemente si è svolto a Roma un evento dimostrativo per informare, professionisti e ricercatori del settore inerente il rilievo strumentale, sulle recenti innovazioni che riguardano i laser scanner 3d. Il mercato della strumentazione dedicata al rilevamento architettonico e dell'ambiente, offre molte possibilità di scelta. Oggi i principali marchi producono strumenti sempre più efficienti ed ideati per ambiti di applicazione specifici, permettendo ai professionisti, la giusta scelta in termini di prestazioni ed economia.A demonstration event was recently held in Rome with the aim to inform professionals and researchers on recent innovations on instrumental survey related to the 3d laser scanner. The market of instrumentation for architectural survey offers many possibilitiesof choice. Today the major brands produce instruments that are more efficient and designed for specific areas of application, allowing the right choice in terms of performance and economy.

  14. Structural, mechanical and optical studies on ultrafast laser inscribed chalcogenide glass waveguide

    Science.gov (United States)

    Ayiriveetil, Arunbabu; Varma, G. Sreevidya; Chaturvedi, Abhishek; Sabapathy, Tamilarasan; Ramamurty, Upadrasta; Asokan, Sundarrajan

    2017-04-01

    Multi-scan waveguides have been inscribed in GeS2 glass sample with different pulse energies and translation speeds. Mechanical and structural changes on GeS2 binary glass in response to irradiation to 1047 nm femto-second laser pulses have been investigated. The optical characterization of these waveguides has been done at 1550 nm of laser wavelength and the material response to laser exposure is characterized by both nanoindentation studies and micro-Raman spectroscopy. Nanoindentation investigations show a decrease in hardness (H) and elastic modulus (E) upon laser irradiation. The change in E and H are found to be varying with the translational speed, pulse energy and hence the net-fluence at the sample. These changes are correlated with variations in the Raman response of photo-exposed glass which is interpreted in terms of structural modifications made by the laser inscriptions to the glassy network. The mechanical behavior and local structural changes on waveguide writing is found to be dependent on net-fluence and it is correlated with the preparation conditions like melt temperature and cooling rate.

  15. 3D laser microfabrication principles and applications

    CERN Document Server

    Misawa, Hiroaki

    2006-01-01

    A thorough introduction to 3D laser microfabrication technology, leading readers from the fundamentals and theory to its various potent applications, such as the generation of tiny objects or three-dimensional structures within the bulk of transparent materials. The book also presents new theoretical material on dielectric breakdown, allowing a better understanding of the differences between optical damage on surfaces and inside the bulk, as well as a look into the future.Chemists, physicists, materials scientists and engineers will find this a valuable source of interdisciplinary know

  16. Narrow linewidth Yb-doped double-cladding fiber laser utilizing fiber Bragg gratings inscribed by femtosecond pulses

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhinan; Shi Jiawei; Zhang Jihuang; Wang Haiyan; Li Yuhua; Lu Peixiang, E-mail: oeyhli@gmail.com, E-mail: lupeixiang@mail.hust.edu.cn [Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-02-01

    A narrow-linewidth high power laser in all fiber format at 1064 nm is demonstrated. The resonant cavity is composed of two distributed Bragg reflector (DBR) fiber gratings, which were inscribed into the core of the double-cladding fiber by use of 800 nm femtosecond laser pulses and a phase mask. The spectrum of the laser exhibited a narrow linewidth of 21 pm at the output power of 0.8 W. The wavelength and power of the laser featured long term stability.

  17. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc. (ASC) is a small business that has developed 3D Flash LIDAR systems for space and terrestrial applications. 3D Flash LIDAR is...

  18. 3D scene reconstruction based on 3D laser point cloud combining UAV images

    Science.gov (United States)

    Liu, Huiyun; Yan, Yangyang; Zhang, Xitong; Wu, Zhenzhen

    2016-03-01

    It is a big challenge capturing and modeling 3D information of the built environment. A number of techniques and technologies are now in use. These include GPS, and photogrammetric application and also remote sensing applications. The experiment uses multi-source data fusion technology for 3D scene reconstruction based on the principle of 3D laser scanning technology, which uses the laser point cloud data as the basis and Digital Ortho-photo Map as an auxiliary, uses 3DsMAX software as a basic tool for building three-dimensional scene reconstruction. The article includes data acquisition, data preprocessing, 3D scene construction. The results show that the 3D scene has better truthfulness, and the accuracy of the scene meet the need of 3D scene construction.

  19. 3D Flash LIDAR Space Laser Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced Scientific Concepts, Inc (ASC) is a small business, which has developed a compact, eye-safe 3D Flash LIDARTM Camera (FLC) well suited for real-time...

  20. Femtosecond-laser inscribed double-cladding waveguides in Nd:YAG crystal: a promising prototype for integrated lasers.

    Science.gov (United States)

    Liu, Hongliang; Chen, Feng; Vázquez de Aldana, Javier R; Jaque, D

    2013-09-01

    We report on the design and implementation of a prototype of optical waveguides fabricated in Nd:YAG crystals by using femtosecond-laser irradiation. In this prototype, two concentric tubular structures with nearly circular cross sections of different diameters have been inscribed in the Nd:YAG crystals, generating double-cladding waveguides. Under 808 nm optical pumping, waveguide lasers have been realized in the double-cladding structures. Compared with single-cladding waveguides, the concentric tubular structures, benefiting from the large pump area of the outermost cladding, possess both superior laser performance and nearly single-mode beam profile in the inner cladding. Double-cladding waveguides of the same size were fabricated and coated by a thin optical film, and a maximum output power of 384 mW and a slope efficiency of 46.1% were obtained. Since the large diameters of the outer claddings are comparable with those of the optical fibers, this prototype paves a way to construct an integrated single-mode laser system with a direct fiber-waveguide configuration.

  1. LASER CUTTING MACHINES FOR 3-D THIN SHEET PARTS

    Directory of Open Access Journals (Sweden)

    Miroslav RADOVANOVIC

    2012-11-01

    Full Text Available Laser cutting machines are used for precise contour cutting thin sheet. In industrial application nowadays various types and construction of laser cutting machines can be met. For contour cutting 3-D thin sheet parts laser cutting machines with rotation movements and laser robots are used. Laser generates the light beam, that presents a tool in working process. Application of laser cutting machines made possible good quality of products, flexibility of production and enlargement of economy

  2. 3D Laser Scanning in Technology Education.

    Science.gov (United States)

    Flowers, Jim

    2000-01-01

    A three-dimensional laser scanner can be used as a tool for design and problem solving in technology education. A hands-on experience can enhance learning by captivating students' interest and empowering them with creative tools. (Author/JOW)

  3. 3D laser imaging for concealed object identification

    Science.gov (United States)

    Berechet, Ion; Berginc, Gérard; Berechet, Stefan

    2014-09-01

    This paper deals with new optical non-conventional 3D laser imaging. Optical non-conventional imaging explores the advantages of laser imaging to form a three-dimensional image of the scene. 3D laser imaging can be used for threedimensional medical imaging, topography, surveillance, robotic vision because of ability to detect and recognize objects. In this paper, we present a 3D laser imaging for concealed object identification. The objective of this new 3D laser imaging is to provide the user a complete 3D reconstruction of the concealed object from available 2D data limited in number and with low representativeness. The 2D laser data used in this paper come from simulations that are based on the calculation of the laser interactions with the different interfaces of the scene of interest and from experimental results. We show the global 3D reconstruction procedures capable to separate objects from foliage and reconstruct a threedimensional image of the considered object. In this paper, we present examples of reconstruction and completion of three-dimensional images and we analyse the different parameters of the identification process such as resolution, the scenario of camouflage, noise impact and lacunarity degree.

  4. Laser profiling of 3D microturbine blades

    Science.gov (United States)

    Holmes, Andrew S.; Heaton, Mark E.; Hong, Guodong; Pullen, Keith R.; Rumsby, Phil T.

    2003-11-01

    We have used KrF excimer laser ablation in the fabrication of a novel MEMS power conversion device based on an axial-flow turbine with an integral axial-flux electromagnetic generator. The device has a sandwich structure, comprising a pair of silicon stators either side of an SU8 polymer rotor. The curved turbine rotor blades were fabricated by projection ablation of SU8 parts performed by conventional UV lithography. A variable aperture mask, implemented by stepping a moving aperture in front of a fixed one, was used to achieve the desired spatial variation in the ablated depth. An automatic process was set up on a commercial laser workstation, with the laser firing and mask motion being controlled by computer. High quality SU8 rotor parts with diameters of 13 mm and depths of 1 mm were produced at a fluence of 0.7 J/cm2, corresponding to a material removal rate of approximately 0.3 μm per pulse. A similar approach was used to form SU8 guide vane inserts for the stators.

  5. Terahertz Quantum Cascade Laser Based 3D Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — LongWave Photonics proposes a terahertz quantum-cascade laser based swept-source optical coherence tomography (THz SS-OCT) system for single-sided, 3D,...

  6. 3D laser methods for calibrating and localising robotic vehicles

    OpenAIRE

    Mark Sheehan

    2013-01-01

    This thesis is about the construction and automatic target-less calibration of a 3D laser sensor; this is then used to localise an autonomous vehicle without using other sensors. Two novel contributions to our knowledge of robotics are presented here. The first is an automatic calibration routine, which is capable of learning its calibration parameters using only data from a 3D laser scanner. Targets with known dimensions are not required, as has previously been the case. The second main ...

  7. High Speed Laser 3D Measurement System

    Institute of Scientific and Technical Information of China (English)

    SONG Yuan-he; FAN Chang-zhou; GUO Ying; LI Hong-wei; ZHAO Hong

    2003-01-01

    Using the method of line structure light produced by a laser diode,three dimensional profile measurement is deeply researched.A hardware circuit developed is used to get the center position of light section for the improvement of the measurement speed.A double CCD compensation technology is used to improve the measurement precision. An easy and effective calibration method of the least squares to fit the parameter of system structure is used to get the relative coordinate relationship of objects and images of light section in the directions of height and axis. Sensor scanning segment by segment and layer by layer makes the measurement range expand greatly.

  8. Towards manipulating relativistic laser pulses with 3D printed materials

    CERN Document Server

    Ji, L L; Pukhov, A; Freeman, R R; Akli, K U

    2015-01-01

    Efficient coupling of intense laser pulses to solid-density matter is critical to many applications including ion acceleration for cancer therapy. At relativistic intensities, the focus has been mainly on investigating various laser beams irradiating initially flat interfaces with little or no control over the interaction. Here, we propose a novel approach that leverages recent advancements in 3D direct laser writing (DLW) of materials and high contrast lasers to manipulate the laser-matter interactions on the micro-scales. We demonstrate, via simulations, that usable intensities >10^23Wcm^(-2) could be achieved with current tabletop lasers coupled to 3D printed plasma lenses. We show that these plasma optical elements act not only as a lens to focus laser light, but also as an electromagnetic guide for secondary particle beams. These results open new paths to engineering light-matter interactions at ultra-relativistic intensities.

  9. Refractive index and dispersion control of ultrafast laser inscribed waveguides in gallium lanthanum sulphide for near and mid-infrared applications

    DEFF Research Database (Denmark)

    Demetriou, Giorgos; Berube, Jean-Philippe; Vallee, Real

    2016-01-01

    The powerful ultrafast laser inscription technique is used to fabricate optical waveguides in gallium lanthanum sulphide substrates. For the first time the refractive index profile and the dispersion of such ultrafast laser inscribed waveguides are experimentally measured. In addition the Zero Di...... in gallium lanthanum sulphide glasses for near and mid-IR applications. (C) 2016 Optical Society of America...

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    Cezary Specht

    2016-07-01

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

  12. Laser printing of cells into 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Ovsianikov, A; Gruene, M; Koch, L; Maiorana, F; Chichkov, B [Nanotechnology Department, Laser Zentrum Hannover eV, Hollerithallee 8, 30419 Hannover (Germany); Pflaum, M; Wilhelmi, M; Haverich, A, E-mail: a.ovsianikov@lzh.d [Medizinische Hochschule Hannover, Carl-Neuberg-Strasse 1, 30625 Hannover (Germany)

    2010-03-15

    One of the most promising approaches in tissue engineering is the application of 3D scaffolds, which provide cell support and guidance in the initial tissue formation stage. The porosity of the scaffold and internal pore organization influence cell migration and play a major role in its biodegradation dynamics, nutrient diffusion and mechanical stability. In order to control cell migration and cellular interactions within the scaffold, novel technologies capable of producing 3D structures in accordance with predefined design are required. The two-photon polymerization (2PP) technique, used in this report for the fabrication of scaffolds, allows the realization of arbitrary 3D structures with submicron spatial resolution. Highly porous 3D scaffolds, produced by 2PP of acrylated poly(ethylene glycol), are seeded with cells by means of laser-induced forward transfer (LIFT). In this laser printing approach, a propulsive force, resulting from laser-induced shock wave, is used to propel individual cells or cell groups from a donor substrate towards the receiver substrate. We demonstrate that with this technique printing of multiple cell types into 3D scaffolds is possible. Combination of LIFT and 2PP provides a route for the realization of 3D multicellular tissue constructs and artificial ECM engineered on the microscale.

  13. Laser printing of cells into 3D scaffolds.

    Science.gov (United States)

    Ovsianikov, A; Gruene, M; Pflaum, M; Koch, L; Maiorana, F; Wilhelmi, M; Haverich, A; Chichkov, B

    2010-03-01

    One of the most promising approaches in tissue engineering is the application of 3D scaffolds, which provide cell support and guidance in the initial tissue formation stage. The porosity of the scaffold and internal pore organization influence cell migration and play a major role in its biodegradation dynamics, nutrient diffusion and mechanical stability. In order to control cell migration and cellular interactions within the scaffold, novel technologies capable of producing 3D structures in accordance with predefined design are required. The two-photon polymerization (2PP) technique, used in this report for the fabrication of scaffolds, allows the realization of arbitrary 3D structures with submicron spatial resolution. Highly porous 3D scaffolds, produced by 2PP of acrylated poly(ethylene glycol), are seeded with cells by means of laser-induced forward transfer (LIFT). In this laser printing approach, a propulsive force, resulting from laser-induced shock wave, is used to propel individual cells or cell groups from a donor substrate towards the receiver substrate. We demonstrate that with this technique printing of multiple cell types into 3D scaffolds is possible. Combination of LIFT and 2PP provides a route for the realization of 3D multicellular tissue constructs and artificial ECM engineered on the microscale.

  14. Femtosecond laser-inscribed fiber Bragg gratings for strain monitoring in power cables of offshore wind turbines.

    Science.gov (United States)

    Burgmeier, Jörg; Schippers, Wolfgang; Emde, Nico; Funken, Peter; Schade, Wolfgang

    2011-05-01

    A fiber Bragg grating sensor system used for monitoring the effects of strain on the power cable of an offshore wind turbine is presented. The Bragg grating structure was inscribed into coated nonphotosensitive standard telecommunication fibers using an IR femtosecond laser and the point-by-point writing technique. Because of the presence of the protective coating of the fiber, the mechanical stability of the resultant sensor device is better than that of a sensor consisting of a bare fiber. A system containing this sensing element was to our knowledge for the first time successfully installed and tested in an offshore wind turbine prototype (REpower 6M, REpower Systems, AG, Germany) in February 2010, near Ellhöft (Germany). The fabrication process of the fiber Bragg gratings, measurement results of the online monitoring, and a comparison between the sensor signal and commonly used sensing techniques are presented.

  15. Automated rock mass characterisation using 3-D terrestrial laser scanning

    NARCIS (Netherlands)

    Slob, S.

    2010-01-01

    The research investigates the possibility of using point cloud data from 3-D terrestrial laser scanning as a basis to characterise discontinuities in exposed rock massed in an automated way. Examples of discontinuities in rock are bedding planes, joints, fractures and schistocity. The characterisati

  16. 3d particle simulations on ultra short laser interaction

    Energy Technology Data Exchange (ETDEWEB)

    Nishihara, Katsunobu; Okamoto, Takashi; Yasui, Hidekazu [Osaka Univ., Suita (Japan). Inst. of Laser Engineering

    1998-03-01

    Two topics related to ultra short laser interaction with matter, linear and nonlinear high frequency conductivity of a solid density hydrogen plasma and anisotropic self-focusing of an intense laser in an overdense plasma, have been investigated with the use of 3-d particle codes. Frequency dependence of linear conductivity in a dense plasma is obtained, which shows anomalous conductivity near plasma frequency. Since nonlinear conductivity decreases with v{sub o}{sup -3}, where v{sub o} is a quivering velocity, an optimum amplitude exists leading to a maximum electron heating. Anisotropic self-focusing of a linear polarized intense laser is observed in an overdense plasma. (author)

  17. Measurement of Laser Weld Temperatures for 3D Model Input.

    Energy Technology Data Exchange (ETDEWEB)

    Dagel, Daryl; GROSSETETE, GRANT; Maccallum, Danny O.

    2016-10-01

    Laser welding is a key joining process used extensively in the manufacture and assembly of critical components for several weapons systems. Sandia National Laboratories advances the understanding of the laser welding process through coupled experimentation and modeling. This report summarizes the experimental portion of the research program, which focused on measuring temperatures and thermal history of laser welds on steel plates. To increase confidence in measurement accuracy, researchers utilized multiple complementary techniques to acquire temperatures during laser welding. This data serves as input to and validation of 3D laser welding models aimed at predicting microstructure and the formation of defects and their impact on weld-joint reliability, a crucial step in rapid prototyping of weapons components.

  18. Object 3D surface reconstruction approach using portable laser scanner

    Science.gov (United States)

    Xu, Ning; Zhang, Wei; Zhu, Liye; Li, Changqing; Wang, Shifeng

    2017-06-01

    The environment perception plays the key role for a robot system. The 3D surface of the objects can provide essential information for the robot to recognize objects. This paper present an approach to reconstruct objects' 3D surfaces using a portable laser scanner we designed which consists of a single-layer laser scanner, an encoder, a motor, power supply and mechanical components. The captured point cloud data is processed to remove the discrete points, denoise filtering, stitching and registration. Then the triangular mesh generation of point cloud is accomplished by using Gaussian bilateral filtering, ICP real-time registration and greedy triangle projection algorithm. The experiment result shows the feasibility of the device designed and the algorithm proposed.

  19. Laser Ultrasound Spectroscopy Scanning for 3D Printed Parts

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-08-04

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

  20. Automatic inventory of components by laser 3D scanner; Inventario de automatico de componentes mediante laser escaner 3D

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Garcia, R.; Munoz Prieto, C.; Sarti Fernandez, F.

    2014-07-01

    One of the existing needs in nuclear decommissioning projects is to provide an inventory of components to be dismantled, which is available from its spatial location and elements that exist in your environment. The Laser scanner technology is a system of data acquisition that allows 3D models composed of millions of points, it's models with pinpoint accuracy and are available in a very short space of time. (Author)

  1. 3D sensor for indirect ranging with pulsed laser source

    Science.gov (United States)

    Bronzi, D.; Bellisai, S.; Villa, F.; Scarcella, C.; Bahgat Shehata, A.; Tosi, A.; Padovini, G.; Zappa, F.; Tisa, S.; Durini, D.; Weyers, S.; Brockherde, W.

    2012-10-01

    The growing interest for fast, compact and cost-effective 3D ranging imagers for automotive applications has prompted to explore many different techniques for 3D imaging and to develop new system for this propose. CMOS imagers that exploit phase-resolved techniques provide accurate 3D ranging with no complex optics and are rugged and costeffective. Phase-resolved techniques indirectly measure the round-trip return of the light emitted by a laser and backscattered from a distant target, computing the phase delay between the modulated light and the detected signal. Singlephoton detectors, with their high sensitivity, allow to actively illuminate the scene with a low power excitation (less than 10W with diffused daylight illumination). We report on a 4x4 array of CMOS SPAD (Single Photon Avalanche Diodes) designed in a high-voltage 0.35 μm CMOS technology, for pulsed modulation, in which each pixel computes the phase difference between the laser and the reflected pulse. Each pixel comprises a high-performance 30 μm diameter SPAD, an analog quenching circuit, two 9 bit up-down counters and memories to store data during the readout. The first counter counts the photons detected by the SPAD in a time window synchronous with the laser pulse and integrates the whole echoed signal. The second counter accumulates the number of photon detected in a window shifted with respect to the laser pulse, and acquires only a portion of the reflected signal. The array is readout with a global shutter architecture, using a 100 MHz clock; the maximal frame rate is 3 Mframe/s.

  2. 3D Laser Triangulation for Plant Phenotyping in Challenging Environments.

    Science.gov (United States)

    Kjaer, Katrine Heinsvig; Ottosen, Carl-Otto

    2015-06-09

    To increase the understanding of how the plant phenotype is formed by genotype and environmental interactions, simple and robust high-throughput plant phenotyping methods should be developed and considered. This would not only broaden the application range of phenotyping in the plant research community, but also increase the ability for researchers to study plants in their natural environments. By studying plants in their natural environment in high temporal resolution, more knowledge on how multiple stresses interact in defining the plant phenotype could lead to a better understanding of the interaction between plant responses and epigenetic regulation. In the present paper, we evaluate a commercial 3D NIR-laser scanner (PlantEye, Phenospex B.V., Herleen, The Netherlands) to track daily changes in plant growth with high precision in challenging environments. Firstly, we demonstrate that the NIR laser beam of the scanner does not affect plant photosynthetic performance. Secondly, we demonstrate that it is possible to estimate phenotypic variation amongst the growth pattern of ten genotypes of Brassica napus L. (rapeseed), using a simple linear correlation between scanned parameters and destructive growth measurements. Our results demonstrate the high potential of 3D laser triangulation for simple measurements of phenotypic variation in challenging environments and in a high temporal resolution.

  3. Ultrafast laser inscribed integrated waveguide components for L-band interferometry

    Science.gov (United States)

    Arriola, A.; Mukherjee, S.; Choudhury, Debaditya; Labadie, L.; Thomson, R. R.

    2014-07-01

    In this paper we report the fabrication and mid-infrared characterization (λ = 3.39 μm) of evanescent field directional couplers. These devices were fabricated using the femtosecond laser direct-writing technique in commercially available Gallium Lanthanum Sulphide (GLS) glass substrates. We demonstrate that the power splitting ratios of the devices can be controlled by adjusting the length of the interaction section between the waveguides, and consequently we demonstrate power splitting ratios of between 8% and 99% for 3.39 μm light. We anticipate that mid-IR beam integrated-optic beam combination instruments based on this technology will be key for future mid-infrared astronomical interferometry, particularly for nulling interferometry and earth-like exoplanet imaging.

  4. Laser embedding electronics on 3D printed objects

    Science.gov (United States)

    Kirleis, Matthew A.; Simonson, Duane; Charipar, Nicholas A.; Kim, Heungsoo; Charipar, Kristin M.; Auyeung, Ray C. Y.; Mathews, Scott A.; Piqué, Alberto

    2014-03-01

    Additive manufacturing techniques such as 3D printing are able to generate reproductions of a part in free space without the use of molds; however, the objects produced lack electrical functionality from an applications perspective. At the same time, techniques such as inkjet and laser direct-write (LDW) can be used to print electronic components and connections onto already existing objects, but are not capable of generating a full object on their own. The approach missing to date is the combination of 3D printing processes with direct-write of electronic circuits. Among the numerous direct write techniques available, LDW offers unique advantages and capabilities given its compatibility with a wide range of materials, surface chemistries and surface morphologies. The Naval Research Laboratory (NRL) has developed various LDW processes ranging from the non-phase transformative direct printing of complex suspensions or inks to lase-and-place for embedding entire semiconductor devices. These processes have been demonstrated in digital manufacturing of a wide variety of microelectronic elements ranging from circuit components such as electrical interconnects and passives to antennas, sensors, actuators and power sources. At NRL we are investigating the combination of LDW with 3D printing to demonstrate the digital fabrication of functional parts, such as 3D circuits. Merging these techniques will make possible the development of a new generation of structures capable of detecting, processing, communicating and interacting with their surroundings in ways never imagined before. This paper shows the latest results achieved at NRL in this area, describing the various approaches developed for generating 3D printed electronics with LDW.

  5. Optical monitoring of scoliosis by 3D medical laser scanner

    Science.gov (United States)

    Rodríguez-Quiñonez, Julio C.; Sergiyenko, Oleg Yu.; Preciado, Luis C. Basaca; Tyrsa, Vera V.; Gurko, Alexander G.; Podrygalo, Mikhail A.; Lopez, Moises Rivas; Balbuena, Daniel Hernandez

    2014-03-01

    Three dimensional recording of the human body surface or anatomical areas have gained importance in many medical applications. In this paper, our 3D Medical Laser Scanner is presented. It is based on the novel principle of dynamic triangulation. We analyze the method of operation, medical applications, orthopedically diseases as Scoliosis and the most common types of skin to employ the system the most proper way. It is analyzed a group of medical problems related to the application of optical scanning in optimal way. Finally, experiments are conducted to verify the performance of the proposed system and its method uncertainty.

  6. An omnidirectional 3D sensor with line laser scanning

    Science.gov (United States)

    Xu, Jing; Gao, Bingtuan; Liu, Chuande; Wang, Peng; Gao, Shuanglei

    2016-09-01

    An active omnidirectional vision owns the advantages of the wide field of view (FOV) imaging, resulting in an entire 3D environment scene, which is promising in the field of robot navigation. However, the existing omnidirectional vision sensors based on line laser can measure points only located on the optical plane of the line laser beam, resulting in the low-resolution reconstruction. Whereas, to improve resolution, some other omnidirectional vision sensors with the capability of projecting 2D encode pattern from projector and curved mirror. However, the astigmatism property of curve mirror causes the low-accuracy reconstruction. To solve the above problems, a rotating polygon scanning mirror is used to scan the object in the vertical direction so that an entire profile of the observed scene can be obtained at high accuracy, without of astigmatism phenomenon. Then, the proposed method is calibrated by a conventional 2D checkerboard plate. The experimental results show that the measurement error of the 3D omnidirectional sensor is approximately 1 mm. Moreover, the reconstruction of objects with different shapes based on the developed sensor is also verified.

  7. 3D laser lithography: Quo vadis? (Conference Presentation)

    Science.gov (United States)

    Wegener, Martin

    2017-02-01

    3D printing on the macroscale is a huge trend worldwide. Ultimately, one would like to 3D print anything, including complete functional devices. Apart from boosting printing speed and pushing spatial resolution to the nanometer scale, 3D printing of many different materials poses a major challenge. In 2D graphical printers, thousands of different colors can be printed from just three color cartridges. By analogy, future 3D printers may print thousands of effective (meta-)materials from just a few materials cartridges. These metamaterials should not only be tailored in terms of their optical properties, but also electrical, magnetic, thermodynamic, mechanical, and bio-chemical.

  8. Mobile 3D laser scanning technology application in the surveying of urban underground rail transit

    Science.gov (United States)

    Han, Youmei; Yang, Bogang; Zhen, Yinan

    2016-11-01

    Mobile 3D laser scanning technology is one hot kind of digital earth technology. 3D completion surveying is relative new concept in surveying and mapping. A kind of mobile 3D laser scanning system was developed for the urban underground rail 3D completion surveying. According to the characteristics of underground rail environment and the characters of the mobile laser scanning system, it designed a suitable test scheme to improving the accuracy of this kind of mobile laser scanning system when it worked under no GPS signal environment. Then it completed the application of this technology in the No.15 rail 3D completion surveying. Meanwhile a set of production process was made for the 3D completion surveying based on this kind of mobile 3D laser scanning technology. These products were also proved the efficiency of the new technology in the rail 3D completion surveying. Using mobile 3D laser scanning technology to complete underground rail completion surveying has been the first time in China until now. It can provide a reference for 3D measurement of rail completion surveying or the 3D completion surveying of other areas.

  9. Inequalities for inscribed simplexes

    Institute of Scientific and Technical Information of China (English)

    YANG Shiguo

    2004-01-01

    The problem on the geometrc inequalities involving ann-dimensional simplex and its inscribed simplex is studied. An inequality is established, which reveals that the difference between the squared circumradius of then-dimensional simplex and the squared distance between its circumcenter and barycenter times the squared circumradius of its inscribed simplex is not less than the 2(n-1)th power ofnn times its squared inradius, and is equal to when the simplex is regular and its inscribed siplex is a tangent point one. Deduction from this inequality reaches a generalization ofn-dimensional Euler inequality indicating that the circumradius of the simplex is not less than then-fold inradius. Another inequality is derived to present the relationship between the circumradius of the n-dimensional simplex and the circumradius and inradius of its pedal simplex.

  10. Bore-Sight Calibration of Multiple Laser Range Finders for Kinematic 3D Laser Scanning Systems

    Directory of Open Access Journals (Sweden)

    Jaehoon Jung

    2015-05-01

    Full Text Available The Simultaneous Localization and Mapping (SLAM technique has been used for autonomous navigation of mobile systems; now, its applications have been extended to 3D data acquisition of indoor environments. In order to reconstruct 3D scenes of indoor space, the kinematic 3D laser scanning system, developed herein, carries three laser range finders (LRFs: one is mounted horizontally for system-position correction and the other two are mounted vertically to collect 3D point-cloud data of the surrounding environment along the system’s trajectory. However, the kinematic laser scanning results can be impaired by errors resulting from sensor misalignment. In the present study, the bore-sight calibration of multiple LRF sensors was performed using a specially designed double-deck calibration facility, which is composed of two half-circle-shaped aluminum frames. Moreover, in order to automatically achieve point-to-point correspondences between a scan point and the target center, a V-shaped target was designed as well. The bore-sight calibration parameters were estimated by a constrained least squares method, which iteratively minimizes the weighted sum of squares of residuals while constraining some highly-correlated parameters. The calibration performance was analyzed by means of a correlation matrix. After calibration, the visual inspection of mapped data and residual calculation confirmed the effectiveness of the proposed calibration approach.

  11. 3D cavity detection technique and its application based on cavity auto scanning laser system

    Institute of Scientific and Technical Information of China (English)

    LIU Xi-ling; LI Xi-bing; LI Fa-ben; ZHAO Guo-yan; QIN Yu-hui

    2008-01-01

    Ground constructions and mines are severely threatened by underground cavities especially those unsafe or inaccessible ones. Safe and precise cavity detection is vital for reasonable cavity evaluation and disposal. The conventional cavity detection methods and their limitation were analyzed. Those methods cannot form 3D model of underground cavity which is used for instructing the cavity disposal; and their precisions in detection are always greatly affected by the geological circumstance. The importance of 3D cavity detection in metal mine for safe exploitation was pointed out; and the 3D cavity laser detection method and its principle were introduced. A cavity auto scanning laser system was recommended to actualize the cavity 3D detection after comparing with the other laser detection systems. Four boreholes were chosen to verify the validity of the cavity auto scanning laser system. The results show that the cavity auto scanning laser system is very suitable for underground 3D cavity detection, especially for those inaccessible ones.

  12. Laser induced forward transfer of interconnects for 3D integration

    NARCIS (Netherlands)

    Oosterhuis, G.; Prenen, A.; Huis in 't veld, A.J.

    2011-01-01

    Interconnects are an important cost driver in advanced 3D chip packaging. This holds for Through Silicon Vias (TSVs) for chip stacking, but also for other interconnect steps like re-distribution layers and solder bumps. Especially in applications with a low number (<100 mm-2) of relatively large

  13. Ellipses Inscribed in Parallelograms

    CERN Document Server

    Horwitz, Alan

    2008-01-01

    We prove that there exists a unique ellipse of minimal eccentricity, E_{I}, inscribed in a parallelogram, D. We also prove that the smallest nonnegative angle between equal conjugate diameters of E_{I} equals the smallest nonnegative angle between the diagonals of D. We also prove that if E_{M} is the unique ellipse inscribed in a rectangle, R, which is tangent at the midpoints of the sides of R, then E_{M} is the unique ellipse of minimal eccentricity, maximal area, and maximal arc length inscribed in R. Let D be any convex quadrilateral. In previous papers, the author proved that there is a unique ellipse of minimal eccentricity, E_{I}, inscribed in D, and a unique ellipse, E_{O}, of minimal eccentricity circumscribed about D. We defined D to be bielliptic if E_{I} and E_{O} have the same eccentricity. In this paper we show that a parallelogram, D, is bielliptic if and only if the square of the length of one of the diagonals of D equals twice the square of the length of one of the sides of D.

  14. Large-scale three-dimensional measurement via combining 3D scanner and laser rangefinder.

    Science.gov (United States)

    Shi, Jinlong; Sun, Zhengxing; Bai, Suqin

    2015-04-01

    This paper presents a three-dimensional (3D) measurement method of large-scale objects by integrating a 3D scanner and a laser rangefinder. The 3D scanner, used to perform partial section measurement, is fixed on a robotic arm which can slide on a guide rail. The laser rangefinder, used to compute poses of the 3D scanner, is rigidly connected to the 3D scanner. During large-scale measurement, after measuring a partial section, the 3D scanner is straightly moved forward along the guide rail to measure another section. Meanwhile, the poses of the 3D scanner are estimated according to its moved distance for different partial section alignments. The performance and effectiveness are evaluated by experiments.

  15. Femtosecond laser 3D micromachining for microfluidic and optofluidic applications

    CERN Document Server

    Sugioka, Koji

    2013-01-01

    Femtosecond lasers opened up new avenue in materials processing due to its unique features of ultrashort pulse width and extremely high peak intensity. One of the most important features of femtosecond laser processing is that strong absorption can be induced even by materials which are transparent to the femtosecond laser beam due to nonlinear multiphoton absorption. The multiphoton absorption allows us to perform not only surface but also three-dimensionally internal microfabrication of transparent materials such as glass. This capability makes it possible to directly fabricate three-dimensi

  16. (HEL MRI) 3D Meta Optics for High Energy Lasers

    Science.gov (United States)

    2016-09-13

    optical communication link using orbital angular momentum multiplexing ." Optics express 24, no. 9 (2016): 9794-9805. 3. Li, Yuan, Wenzhe Li, J. Miller, and...Magnusson, R.; Binun, P.; McCormick, K., "Wavelength Selection and Polarization Multiplexing of Blue Laser Diodes," in Photonics Technology Letters, IEEE...spatial multiplexing can take advantage of a non-Gaussian beam profile. If the components are to be used as out-couplers in bulk lasers , the optics

  17. Mid-IR (3-4 μm) fluorescence and ASE studies in Dy3+ doped tellurite and germanate glasses and a fs laser inscribed waveguide

    Science.gov (United States)

    Richards, B. D. O.; Teddy-Fernandez, T.; Jose, G.; Binks, D.; Jha, A.

    2013-08-01

    We present the fluorescence spectroscopy of a range of Dy3+ doped tellurite (TeO2) and germanate (GeO2) glasses and compare with Dy3+ doped ZBLAN glass. When excited using an 808 nm laser diode, Dy3+ ions emit radiation at around 3 μm from the 6H13/2→ 6H15/2 (3500 cm-1) energy level transition, which has been exploited in Dy3+ doped fluoride fibre lasers. When Dy3+ is doped into TeO2 and GeO2 based glasses, the fluorescence from the 6H13/2→ 6H15/2 transition is shown to be broader and red-shifted compared to that in ZBLAN glass. Mid-IR ASE from a fs laser inscribed Dy3+ doped tellurite glass waveguide is also presented. The results of Dy3+ mid-IR fluorescence spectroscopy and the potential of oxide glasses as mid-IR sources are discussed.

  18. Metamaterial 3D Gain Nanostructures Fabricated Using Direct Laser Writing

    Science.gov (United States)

    2015-07-11

    1700 1800 1900 2000 0.0 0.5 1.0 N or m al iz ed In te ns ity (a .u ) Wavelength ( nm ) 1’ 2’ 3’ 4’ 5’ 6’ 8’ 10’ excitation 650 nm ...of a photonic crystal structure of 700 nm period and 240 nm feature size. Structure Fabrication Using Direct Laser Writing (DLW) via the Two-Photon...the laser fabricated photonic crystals. 500 600 700 0 10000 20000 30000 40000 50000 (F L) In te ns

  19. Omnidirectional Perception for Lightweight Uavs Using a Continuously Rotating 3d Laser Scanner

    Science.gov (United States)

    Droeschel, D.; Schreiber, M.; Behnke, S.

    2013-08-01

    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.

  20. Bioceramic 3D Implants Produced by Laser Assisted Additive Manufacturing

    Science.gov (United States)

    Lusquiños, Fernando; del Val, Jesús; Arias-González, Felipe; Comesaña, Rafael; Quintero, Félix; Riveiro, Antonio; Boutinguiza, Mohamed; Jones, Julian R.; Hill, Robert G.; Pou, Juan

    Cranial defect restoration requires a suitable implant capable to fulfill protective and aesthetic functions, such as polymeric and metallic implants. Nevertheless, the former materials cannot provide osteointegration of the implant within the host bone nor implant resorption, which is also required in pediatricorthopedics for normal patient growth. Resorbable and osteoconductivebioceramics are employed, such as silicate bioactive glasses. Nevertheless, manufacturing based on conventional casting in graphite moulds is not effective for warped shape implants suitable for patient tailored treatments. In this work, we analyze the application of rapid prototyping based on laser cladding to manufacture bioactive glass implants for low load bearing bone restoration. This laser-assisted additive technique is capable to produce three-dimensional geometries tailored to patient, with reduced fabrication time and implant composition modification. The obtained samples were characterized; the relationships between the processing conditions and the measured features were studied, in addition to the biological behavior analysis.

  1. Laser-Writing in Silicon for 3D Information Processing

    CERN Document Server

    Tokel, O; Pavlov, I; Tozburun, S; Akca, I; Ilday, F O

    2014-01-01

    Micromachining of silicon with lasers is being investigated since the 1970s. So far generating subsurface modifications buried inside the bulk of the silicon without damaging the surface has not resulted in success. Here, we report a method for photo-inducing buried structures in doped silicon wafers with pulsed infrared lasers without modifying the wafer surface. We demonstrate large aspect-ratio, continuous multilevel subsurface structures, with lengths on the millimetre scale, while having sub-micron widths. We further demonstrate spatial information encoding capabilities embedded in subsurface silicon barcodes based on an optical coherence tomography (OCT) readout. The demonstrated silicon processing technology can be used for the realization of multilayered silicon chips, optofluidics and on-chip quantum optics experiments.

  2. Laser-Directed CVD 3D Printing of Refractory Metal Rocket Propulsion Hardware Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this project, Ultramet will develop a three-dimensional (3D) laser-directed chemical vapor deposition (CVD) additive manufacturing system to build free-form...

  3. Laser direct writing 3D structures for microfluidic channels: flow meter and mixer

    Science.gov (United States)

    Lin, Chih-Lang; Liu, Yi-Jui; Lin, Zheng-Da; Wu, Bo-Long; Lee, Yi-Hsiung; Shin, Chow-Shing; Baldeck, Patrice L.

    2015-03-01

    The 3D laser direct-writing technology is aimed at the modeling of arbitrary three-dimensional (3D) complex microstructures by scanning a laser-focusing point along predetermined trajectories. Through the perspective technique, the details of designed 3D structures can be properly fabricated in a microchannel. This study introduces a direct reading flow meter and a 3D passive mixer fabricated by laser direct writing for microfluidic applications. The flow meter consists of two rod-shaped springs, a pillar, an anchor, and a wedge-shaped indicator, installed inside a microfluidic channel. The indicator is deflected by the flowing fluid while restrained by the spring to establish an equilibrium indication according to the flow rate. The measurement is readily carried out by optical microscopy observation. The 3D passive Archimedes-screw-shaped mixer is designed to disturb the laminar flow 3D direction for enhancing the mixing efficiency. The simulation results indicate that the screw provides 3D disturbance of streamlines in the microchannel. The mixing demonstration for fluids flowing in the micrchannel approximately agrees with the simulation result. Thanks to the advantage of the laser direct writing technology, this study performs the ingenious applications of 3D structures for microchannels.

  4. Investigation Into the Utilization of 3D Printing in Laser Cooling Experiments

    Science.gov (United States)

    Hazlett, Eric; Nelson, Brandon; de Leon, Sam Diaz; Shaw, Jonah

    2016-05-01

    With the advancement of 3D printing new opportunities are abound in many different fields, but with the balance between the precisions of atomic physics experiments and the material properties of current 3D printers the benefit of 3D printing technology needs to be investigated. We report on the progress of two investigations of 3D printing of benefit to atomic physics experiments: laser feedback module and the other being an optical chopper. The first investigation looks into creation of a 3D printed laser diode feedback module. This 3D printed module would allow for the quick realization of an external cavity diode laser that would have an adjustable cavity distance. We will report on the first tests of this system, by looking at Rb spectroscopy and mode-hop free tuning range as well as possibilities of using these lasers for MOT generation. We will also discuss our investigation into a 3D-printed optical chopper that utilizes an Arduino and a computer hard drive motor. By implementing an additional Arduino we create a low cost way to quickly measure laser beam waists.

  5. Laser-assisted direct ink writing of planar and 3D metal architectures

    Science.gov (United States)

    Skylar-Scott, Mark A.; Gunasekaran, Suman; Lewis, Jennifer A.

    2016-05-01

    The ability to pattern planar and freestanding 3D metallic architectures at the microscale would enable myriad applications, including flexible electronics, displays, sensors, and electrically small antennas. A 3D printing method is introduced that combines direct ink writing with a focused laser that locally anneals printed metallic features “on-the-fly.” To optimize the nozzle-to-laser separation distance, the heat transfer along the printed silver wire is modeled as a function of printing speed, laser intensity, and pulse duration. Laser-assisted direct ink writing is used to pattern highly conductive, ductile metallic interconnects, springs, and freestanding spiral architectures on flexible and rigid substrates.

  6. Laser-assisted direct ink writing of planar and 3D metal architectures.

    Science.gov (United States)

    Skylar-Scott, Mark A; Gunasekaran, Suman; Lewis, Jennifer A

    2016-05-31

    The ability to pattern planar and freestanding 3D metallic architectures at the microscale would enable myriad applications, including flexible electronics, displays, sensors, and electrically small antennas. A 3D printing method is introduced that combines direct ink writing with a focused laser that locally anneals printed metallic features "on-the-fly." To optimize the nozzle-to-laser separation distance, the heat transfer along the printed silver wire is modeled as a function of printing speed, laser intensity, and pulse duration. Laser-assisted direct ink writing is used to pattern highly conductive, ductile metallic interconnects, springs, and freestanding spiral architectures on flexible and rigid substrates.

  7. O Laser Scanner e a Paleontologia em 3D

    Directory of Open Access Journals (Sweden)

    Marco André Malmann Medeiros

    2007-07-01

    Full Text Available The introduction of laser scanning for imaging let paleontologists determinate, with higher detail level,the taphonomic positions of fossils in a rock outcrop. It also registers, with millimeters precision, the shape and position of some ichnofossil, like tracks and footprints. With all that, entire digital rock outcrops can becreated and preserved for future studies.The initial data acquired by the software Cyclone is editable in any CAD software, allowing their rendering as well as the possibility of a future reconstruction using prototypes.

  8. The Use of Airborne and Mobile Laser Scanning for Modeling Railway Environments in 3D

    Directory of Open Access Journals (Sweden)

    Lingli Zhu

    2014-04-01

    Full Text Available This paper presents methods for 3D modeling of railway environments from airborne laser scanning (ALS and mobile laser scanning (MLS. Conventionally, aerial data such as ALS and aerial images were utilized for 3D model reconstruction. However, 3D model reconstruction only from aerial-view datasets can not meet the requirement of advanced visualization (e.g., walk-through visualization. In this paper, objects in a railway environment such as the ground, railroads, buildings, high voltage powerlines, pylons and so on were reconstructed and visualized in real-life experiments in Kokemaki, Finland. Because of the complex terrain and scenes in railway environments, 3D modeling is challenging, especially for high resolution walk-through visualizations. However, MLS has flexible platforms and provides the possibility of acquiring data in a complex environment in high detail by combining with ALS data to produce complete 3D scene modeling. A procedure from point cloud classification to 3D reconstruction and 3D visualization is introduced, and new solutions are proposed for object extraction, 3D reconstruction, model simplification and final model 3D visualization. Image processing technology is used for the classification, 3D randomized Hough transformations (RHT are used for the planar detection, and a quadtree approach is used for the ground model simplification. The results are visually analyzed by a comparison with an orthophoto at a 20 cm ground resolution.

  9. Annular beam shaping system for advanced 3D laser brazing

    Science.gov (United States)

    Pütsch, Oliver; Stollenwerk, Jochen; Kogel-Hollacher, Markus; Traub, Martin

    2012-10-01

    As laser brazing benefits from advantages such as smooth joints and small heat-affected zones, it has become established as a joining technology that is widely used in the automotive industry. With the processing of complex-shaped geometries, recent developed brazing heads suffer, however, from the need for continuous reorientation of the optical system and/or limited accessibility due to lateral wire feeding. This motivates the development of a laser brazing head with coaxial wire feeding and enhanced functionality. An optical system is designed that allows to generate an annular intensity distribution in the working zone. The utilization of complex optical components avoids obscuration of the optical path by the wire feeding. The new design overcomes the disadvantages of the state-of-the-art brazing heads with lateral wire feeding and benefits from the independence of direction while processing complex geometries. To increase the robustness of the brazing process, the beam path also includes a seam tracking system, leading to a more challenging design of the whole optical train. This paper mainly discusses the concept and the optical design of the coaxial brazing head, and also presents the results obtained with a prototype and selected application results.

  10. 3D reconstruction with two webcams and a laser line projector

    Science.gov (United States)

    Li, Dongdong; Hui, Bingwei; Qiu, Shaohua; Wen, Gongjian

    2014-09-01

    Three-dimensional (3D) reconstruction is one of the most attractive research topics in photogrammetry and computer vision. Nowadays 3D reconstruction with simple and consumable equipment plays an important role. In this paper, a 3D reconstruction desktop system is built based on binocular stereo vision using a laser scanner. The hardware requirements are a simple commercial hand-held laser line projector and two common webcams for image acquisition. Generally, 3D reconstruction based on passive triangulation methods requires point correspondences among various viewpoints. The development of matching algorithms remains a challenging task in computer vision. In our proposal, with the help of a laser line projector, stereo correspondences are established robustly from epipolar geometry and the laser shadow on the scanned object. To establish correspondences more conveniently, epipolar rectification is employed using Bouguet's method after stereo calibration with a printed chessboard. 3D coordinates of the observed points are worked out with rayray triangulation and reconstruction outliers are removed with the planarity constraint of the laser plane. Dense 3D point clouds are derived from multiple scans under different orientations. Each point cloud is derived by sweeping the laser plane across the object requiring 3D reconstruction. The Iterative Closest Point algorithm is employed to register the derived point clouds. Rigid body transformation between neighboring scans is obtained to get the complete 3D point cloud. Finally polygon meshes are reconstructed from the derived point cloud and color images are used in texture mapping to get a lifelike 3D model. Experiments show that our reconstruction method is simple and efficient.

  11. Flexible Calibration Method for 3D Laser Scanner System

    Institute of Scientific and Technical Information of China (English)

    杨中东; 王鹏; 李晓慧; 孙长库

    2014-01-01

    In this paper, a flexible high-precision calibration method suitable for industrial field was proposed. The complexity of the coordinate transformation was simplified by choosing the camera coordinate system as the unified reference coordinate system. A flexible planar calibration pattern was introduced to the calibration process, which can be arbitrarily placed and from which the known feature points can be extracted to construct other unknown feature points. With the known intrinsic parameters, the laser projector plane equation was fitted by the multi-noncollinear points, which were acquired through the principle of triangulation and the projective invariance of cross ratio. With this method, the strict alignment and multiple times of coordinate transformation can be avoided. Experimental results showed that the arithmetic mean of the root mean square (RMS) error of distance was 0.000 7 mm.

  12. Formation and properties of 3D metamaterial composites fabricated using nanometer scale laser lithography (Presentation Recording)

    Science.gov (United States)

    Prokes, Sharka M.; Perkins, Frank K.; Glembocki, Orest J.

    2015-08-01

    Metamaterials designed for the visible or near IR wavelengths require patterning on the nanometer scale. To achieve this, e-beam lithography is used, but it is extremely difficult and can only produce 2D structures. A new alternative technique to produce 2D and 3D structures involves laser fabrication using the Nanoscribe 3D laser lithography system. This is a direct laser writing technique which can form arbitrary 3D nanostructures on the nanometer scale and is based on multi-photon polymerization. We are creating 2D and 3D metamaterials via this technique, and subsequently conformally coating them using Atomic Layer Deposition of oxides and Ag. We will discuss the optical properties of these novel composite structures and their potential for dual resonant metamaterials.

  13. Femtosecond-Laser-Inscribed BiB3O6 Nonlinear Cladding Waveguide for Second-Harmonic Generation

    Science.gov (United States)

    Jia, Yuechen; Vázquez de Aldana, Javier R.; Romero, Carolina; Ren, Yingying; Lu, Qingming; Chen, Feng

    2012-07-01

    We report on the fabrication of a nonlinear cladding waveguide in BiB3O6 crystal by using femtosecond laser inscription. The waveguide (with a nearly circular cross section of 150 µm diameter) shows good guiding properties in two transverse polarizations. The guided-wave second-harmonic generation (SHG) at 532 nm green light has been realized under CW and pulsed wave pump at 1064 nm, based on the Type I birefringent phase matching configuration. The conversion efficiencies for CW and pulsed green laser SHG are 0.083 and 25%, respectively.

  14. Portable 3D laser-camera calibration system with color fusion for SLAM

    Directory of Open Access Journals (Sweden)

    Javier Navarrete

    2013-03-01

    Full Text Available Nowadays, the use of RGB-D sensors have focused a lot of research in computer vision and robotics. These kinds of sensors, like Kinect, allow to obtain 3D data together with color information. However, their working range is limited to less than 10 meters, making them useless in some robotics applications, like outdoor mapping. In these environments, 3D lasers, working in ranges of 20-80 meters, are better. But 3D lasers do not usually provide color information. A simple 2D camera can be used to provide color information to the point cloud, but a calibration process between camera and laser must be done. In this paper we present a portable calibration system to calibrate any traditional camera with a 3D laser in order to assign color information to the 3D points obtained. Thus, we can use laser precision and simultaneously make use of color information. Unlike other techniques that make use of a three-dimensional body of known dimensions in the calibration process, this system is highly portable because it makes use of small catadioptrics that can be placed in a simple manner in the environment. We use our calibration system in a 3D mapping system, including Simultaneous Location and Mapping (SLAM, in order to get a 3D colored map which can be used in different tasks. We show that an additional problem arises: 2D cameras information is different when lighting conditions change. So when we merge 3D point clouds from two different views, several points in a given neighborhood could have different color information. A new method for color fusion is presented, obtaining correct colored maps. The system will be tested by applying it to 3D reconstruction.

  15. A hand-held 3D laser scanning with global positioning system of subvoxel precision

    Energy Technology Data Exchange (ETDEWEB)

    Arias, Nestor [GOM, Departamento de Fisica y Geologia, Universidad de Pamplona (Colombia); Meneses, Nestor; Meneses, Jaime [GOTS-CENM, Escuela de Fisica, UIS, Bucaramanga (Colombia); Gharbi, Tijani, E-mail: nesariher@unipamplona.edu.co [Departement D' Optique, FEMTO-ST, 16 Route de Gray, 25030 Besancon (France)

    2011-01-01

    In this paper we propose a hand-held 3D laser scanner composed of an optical head device to extract 3D local surface information and a stereo vision system with subvoxel precision to measure the position and orientation of the 3D optical head. The optical head is manually scanned over the surface object by the operator. The orientation and position of the 3D optical head is determined by a phase-sensitive method using a 2D regular intensity pattern. This phase reference pattern is rigidly fixed to the optical head and allows their 3D location with subvoxel precision in the observation field of the stereo vision system. The 3D resolution achieved by the stereo vision system is about 33 microns at 1.8 m with an observation field of 60cm x 60cm.

  16. Calibration procedure for 3D surface measurements using stereo vision and laser stripe

    OpenAIRE

    Vilaça, João L.; Fonseca, Jaime C.; Pinho, A. C. Marques de

    2006-01-01

    This paper proposes a new stereo vision calibration procedure and laser strip detection for 3D surface measurements. In this calibration procedure the laser plane is the one that matters, only one set of laser-coplanar calibration points is needed for image cameras calibration; and a dead- zone scan area is considered, since the igitalization arm is assembled in a 3 degree-freedom machine PC-based Motion Control with multiple scan paths. It is also presented some algorithms for 3D surface tre...

  17. 3D Monte Carlo simulation of light propagation for laser acupuncture and optimization of illumination parameters

    Science.gov (United States)

    Zhong, Fulin; Li, Ting; Pan, Boan; Wang, Pengbo

    2017-02-01

    Laser acupuncture is an effective photochemical and nonthermal stimulation of traditional acupuncture points with lowintensity laser irradiation, which is advantageous in painless, sterile, and safe compared to traditional acupuncture. Laser diode (LD) provides single wavelength and relatively-higher power light for phototherapy. The quantitative effect of illumination parameters of LD in use of laser acupuncture is crucial for practical operation of laser acupuncture. However, this issue is not fully demonstrated, especially since experimental methodologies with animals or human are pretty hard to address to this issue. For example, in order to protect viability of cells and tissue, and get better therapeutic effect, it's necessary to control the output power varied at 5mW 10mW range, while the optimized power is still not clear. This study aimed to quantitatively optimize the laser output power, wavelength, and irradiation direction with highly realistic modeling of light transport in acupunctured tissue. A Monte Carlo Simulation software for 3D vowelized media and the highest-precision human anatomical model Visible Chinese Human (VCH) were employed. Our 3D simulation results showed that longer wavelength/higher illumination power, larger absorption in laser acupuncture; the vertical direction emission of the acupuncture laser results in higher amount of light absorption in both the acupunctured voxel of tissue and muscle layer. Our 3D light distribution of laser acupuncture within VCH tissue model is potential to be used in optimization and real time guidance in clinical manipulation of laser acupuncture.

  18. 3D electrostatic actuator fabricated by non-ablative femtosecond laser exposure and chemical etching

    Directory of Open Access Journals (Sweden)

    Yang Tao

    2015-01-01

    Full Text Available We demonstrate the novel design of an electrostatic micro-actuator based on monolithic three-dimensional (3D shapes fabricated by non-ablative femtosecond laser exposure combined with chemical etching. Further, we present a single-scan stacking approach exploited in the fabrication of the 3D actuator to create crack-free, highcontrast, high fidelity and integrated micro-structures. Influential parameters: energy per pulse, polarization, scanning spacing and stacking directionwere systematically studied to predict and control the etching rate of 3D planes.Finally, we report the characterization of the actuator and its potential application in optomechanics to show a complete scenario of femtosecond laser machined integrated 3D micro-systems incorporating multiple functionalities.

  19. The research of 3D visualization techniques for the test of laser energy distribution

    Science.gov (United States)

    Liu, Lixin; Wang, Bo

    2013-07-01

    In the process of laser transmission in the atmosphere, the complexity and instability of the atmospheric composition that seriously interfere with, even change, the performance of the laser beam. The image of laser energy distribution can be captured and analyzed through infrared CCD and digital image processing technology. The basic features of laser energy density distribution, such as the location and power of the peak point and other basic parameters could be acquired; laser energy density distribution can display in real time continuous multi-frame; the 3D visualization of pseudo-color for laser energy density distribution could be displayed, that reflect the relative size and position of the energy distribution in the different regions of the laser spot, using the VC++, windows APIs and OpenGL programming. The laser energy density distribution can be observed from all angles.

  20. Laser fabrication of 2D and 3D metal nanoparticle structures and arrays.

    Science.gov (United States)

    Kuznetsov, A I; Kiyan, R; Chichkov, B N

    2010-09-27

    A novel method for fabrication of 2D and 3D metal nanoparticle structures and arrays is proposed. This technique is based on laser-induced transfer of molten metal nanodroplets from thin metal films. Metal nanoparticles are produced by solidification of these nanodroplets. The size of the transferred nanoparticles can be controllably changed in the range from 180 nm to 1500 nm. Several examples of complex 2D and 3D microstructures generated form gold nanoparticles are demonstrated.

  1. Fabrication of 3D embedded hollow structures inside polymer dielectric PMMA with femtosecond laser

    Science.gov (United States)

    Zheng, Chong; Chen, Tao; Hu, Anming; Liu, Shibing; Li, Junwei

    2016-11-01

    Recent progresses in femtosecond laser (fs) manufacturing have already proved that fs laser is a powerful tool in three dimensional internal structure fabrications. However, most studies are mainly focused on realize such structures in inorganic transparent dielectric, such as photosensitive glass and fused silica, etc. In this study, we present two methods to fabricate embedded internal 3D structures in a polymer dielectric material polymethyl methacrylate (PMMA). Both continuous hollow structure such as microfluidic channels and discrete hollow structures such as single microcavities are successfully fabricated with the help of femtosecond lasers. Among them, complicated 3D microchannel with a total length longer than 10mm and diameters around 80μm to 200μm are fabricated with a low repetition rate Ti: sapphire femtosecond laser by direct laser writing at a speed ranging from 25μm/s to 2000μm/s microcavities which function as concave microball lenses (CMBLs) and can be applied in super-wide-angle imaging are fabricated with a high repetition rate femtosecond fiber laser due to the distinct heat accumulation effect after 5s irradiation with the tightly focused fs laser beam. These new approaches proved that femtosecond laser direct writing technology has great application potential in 3D integrated devices manufacturing in the future.

  2. Indoor space 3D visual reconstruction using mobile cart with laser scanner and cameras

    Science.gov (United States)

    Gashongore, Prince Dukundane; Kawasue, Kikuhito; Yoshida, Kumiko; Aoki, Ryota

    2017-02-01

    Indoor space 3D visual reconstruction has many applications and, once done accurately, it enables people to conduct different indoor activities in an efficient manner. For example, an effective and efficient emergency rescue response can be accomplished in a fire disaster situation by using 3D visual information of a destroyed building. Therefore, an accurate Indoor Space 3D visual reconstruction system which can be operated in any given environment without GPS has been developed using a Human-Operated mobile cart equipped with a laser scanner, CCD camera, omnidirectional camera and a computer. By using the system, accurate indoor 3D Visual Data is reconstructed automatically. The obtained 3D data can be used for rescue operations, guiding blind or partially sighted persons and so forth.

  3. A Laser Line Auto-Scanning System for Underwater 3D Reconstruction.

    Science.gov (United States)

    Chi, Shukai; Xie, Zexiao; Chen, Wenzhu

    2016-09-20

    In this study, a laser line auto-scanning system was designed to perform underwater close-range 3D reconstructions with high accuracy and resolution. The system changes the laser plane direction with a galvanometer to perform automatic scanning and obtain continuous laser strips for underwater 3D reconstruction. The system parameters were calibrated with the homography constraints between the target plane and image plane. A cost function was defined to optimize the galvanometer's rotating axis equation. Compensation was carried out for the refraction of the incident and emitted light at the interface. The accuracy and the spatial measurement capability of the system were tested and analyzed with standard balls under laboratory underwater conditions, and the 3D surface reconstruction for a sealing cover of an underwater instrument was proved to be satisfactory.

  4. A Laser Line Auto-Scanning System for Underwater 3D Reconstruction

    Directory of Open Access Journals (Sweden)

    Shukai Chi

    2016-09-01

    Full Text Available In this study, a laser line auto-scanning system was designed to perform underwater close-range 3D reconstructions with high accuracy and resolution. The system changes the laser plane direction with a galvanometer to perform automatic scanning and obtain continuous laser strips for underwater 3D reconstruction. The system parameters were calibrated with the homography constraints between the target plane and image plane. A cost function was defined to optimize the galvanometer’s rotating axis equation. Compensation was carried out for the refraction of the incident and emitted light at the interface. The accuracy and the spatial measurement capability of the system were tested and analyzed with standard balls under laboratory underwater conditions, and the 3D surface reconstruction for a sealing cover of an underwater instrument was proved to be satisfactory.

  5. Fabrication of 3D solenoid microcoils in silica glass by femtosecond laser wet etch and microsolidics

    Science.gov (United States)

    Meng, Xiangwei; Yang, Qing; Chen, Feng; Shan, Chao; Liu, Keyin; Li, Yanyang; Bian, Hao; Du, Guangqing; Hou, Xun

    2015-02-01

    This paper reports a flexible fabrication method for 3D solenoid microcoils in silica glass. The method consists of femtosecond laser wet etching (FLWE) and microsolidics process. The 3D microchannel with high aspect ratio is fabricated by an improved FLWE method. In the microsolidics process, an alloy was chosen as the conductive metal. The microwires are achieved by injecting liquid alloy into the microchannel, and allowing the alloy to cool and solidify. The alloy microwires with high melting point can overcome the limitation of working temperature and improve the electrical property. The geometry, the height and diameter of microcoils were flexibly fabricated by the pre-designed laser writing path, the laser power and etching time. The 3D microcoils can provide uniform magnetic field and be widely integrated in many magnetic microsystems.

  6. Intelligent multisensor concept for image-guided 3D object measurement with scanning laser radar

    Science.gov (United States)

    Weber, Juergen

    1995-08-01

    This paper presents an intelligent multisensor concept for measuring 3D objects using an image guided laser radar scanner. The field of application are all kinds of industrial inspection and surveillance tasks where it is necessary to detect, measure and recognize 3D objects in distances up to 10 m with high flexibility. Such applications might be the surveillance of security areas or container storages as well as navigation and collision avoidance of autonomous guided vehicles. The multisensor system consists of a standard CCD matrix camera and a 1D laser radar ranger which is mounted to a 2D mirror scanner. With this sensor combination it is possible to acquire gray scale intensity data as well as absolute 3D information. To improve the system performance and flexibility, the intensity data of the scene captured by the camera can be used to focus the measurement of the 3D sensor to relevant areas. The camera guidance of the laser scanner is useful because the acquisition of spatial information is relatively slow compared to the image sensor's ability to snap an image frame in 40 ms. Relevant areas in a scene are located by detecting edges of objects utilizing various image processing algorithms. The complete sensor system is controlled by three microprocessors carrying out the 3D data acquisition, the image processing tasks and the multisensor integration. The paper deals with the details of the multisensor concept. It describes the process of sensor guidance and 3D measurement and presents some practical results of our research.

  7. Fabrication of 2D and 3D photonic structures using laser lithography

    Science.gov (United States)

    Gaso, P.; Jandura, D.; Pudis, D.

    2016-12-01

    In this paper we demonstrate possibilities of three-dimensional (3D) printing technology based on two photon polymerization. We used three-dimensional dip-in direct-laser-writing (DLW) optical lithography to fabricate 2D and 3D optical structures for optoelectronics and for optical sensing applications. DLW lithography allows us use a non conventional way how to couple light into the waveguide structure. We prepared ring resonator and we investigated its transmission spectral characteristic. We present 3D inverse opal structure from its design to printing and scanning electron microscope (SEM) imaging. Finally, SEM images of some prepared photonic crystal structures were performed.

  8. 3D printing of weft knitted textile based structures by selective laser sintering of nylon powder

    Science.gov (United States)

    Beecroft, M.

    2016-07-01

    3D printing is a form of additive manufacturing whereby the building up of layers of material creates objects. The selective laser sintering process (SLS) uses a laser beam to sinter powdered material to create objects. This paper builds upon previous research into 3D printed textile based material exploring the use of SLS using nylon powder to create flexible weft knitted structures. The results show the potential to print flexible textile based structures that exhibit the properties of traditional knitted textile structures along with the mechanical properties of the material used, whilst describing the challenges regarding fineness of printing resolution. The conclusion highlights the potential future development and application of such pieces.

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

    Institute of Scientific and Technical Information of China (English)

    DU Jie; CHEN Xiaoyong; FumioYamazaki

    2003-01-01

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

  10. Toward 3D Printing of Pure Metals by Laser-Induced Forward Transfer.

    Science.gov (United States)

    Visser, Claas Willem; Pohl, Ralph; Sun, Chao; Römer, Gert-Willem; Huis in 't Veld, Bert; Lohse, Detlef

    2015-07-15

    3D printing of common metals is highly challenging because metals are generally solid at room conditions. Copper and gold pillars are manufactured with a resolution below 5 μm and a height up to 2 mm, using laser-induced forward transfer to create and eject liquid metal droplets. The solidified drop's shape is crucial for 3D printing and is discussed as a function of the laser energy. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. 3D features of modified photostructurable glass-ceramic with infrared femtosecond laser pulses

    Science.gov (United States)

    Fernández-Pradas, J. M.; Serrano, D.; Bosch, S.; Morenza, J. L.; Serra, P.

    2011-04-01

    The exclusive ability of laser radiation to be focused inside transparent materials makes lasers a unique tool to process inner parts of them unreachable with other techniques. Hence, laser direct-write can be used to create 3D structures inside bulk materials. Infrared femtosecond lasers are especially indicated for this purpose because a multiphoton process is usually required for absorption and high resolution can be attained. This work studies the modifications produced by 450 fs laser pulses at 1027 nm wavelength focused inside a photostructurable glass-ceramic (Foturan ®) at different depths. Irradiated samples were submitted to standard thermal treatment and subsequent soaking in HF solution to form the buried microchannels and thus unveil the modified material. The voxel dimensions of modified material depend on the laser pulse energy and the depth at which the laser is focused. Spherical aberration and self-focusing phenomena are required to explain the observed results.

  12. Black silicon: substrate for laser 3D micro/nano-polymerization.

    Science.gov (United States)

    Žukauskas, Albertas; Malinauskas, Mangirdas; Kadys, Arūnas; Gervinskas, Gediminas; Seniutinas, Gediminas; Kandasamy, Sasikaran; Juodkazis, Saulius

    2013-03-25

    We demonstrate that black silicon (b-Si) made by dry plasma etching is a promising substrate for laser three-dimensional (3D) micro/nano-polymerization. High aspect ratio Si-needles, working as sacrificial support structures, have flexibility required to relax interface stresses between substrate and the polymerized micro-/nano- objects. Surface of b-Si can be made electrically conductive by metal deposition and, at the same time, can preserve low optical reflectivity beneficial for polymerization by direct laser writing. 3D laser polymerization usually performed at the irradiation conditions close to the dielectric breakdown is possible on non-reflective and not metallic surfaces. Here we show that low reflectivity and high metallic conductivity are not counter- exclusive properties for laser polymerization. Electrical conductivity of substrate and its permeability in liquids are promising for bio- and electroplating applications.

  13. LATIS3D: The Gold Standard for Laser-Tissue-Interaction Modeling

    Energy Technology Data Exchange (ETDEWEB)

    London, R.A.; Makarewicz, A.M.; Kim, B.M.; Gentile, N.A.; Yang, Y.B.; Brlik, M.; Vincent, L.

    2000-02-29

    The goal of this LDRD project has been to create LATIS3D--the world's premier computer program for laser-tissue interaction modeling. The development was based on recent experience with the 2D LATIS code and the ASCI code, KULL. With LATIS3D, important applications in laser medical therapy were researched including dynamical calculations of tissue emulsification and ablation, photothermal therapy, and photon transport for photodynamic therapy. This project also enhanced LLNL's core competency in laser-matter interactions and high-energy-density physics by pushing simulation codes into new parameter regimes and by attracting external expertise. This will benefit both existing LLNL programs such as ICF and SBSS and emerging programs in medical technology and other laser applications.

  14. LATIS3D The Gold Standard for Laser-Tissue-Interaction Modeling

    CERN Document Server

    London, R A; Gentile, N A; Kim, B M; Makarewicz, A M; Vincent, L; Yang, Y B

    2000-01-01

    The goal of this LDRD project has been to create LATIS3D--the world's premier computer program for laser-tissue interaction modeling. The development was based on recent experience with the 2D LATIS code and the ASCI code, KULL. With LATIS3D, important applications in laser medical therapy were researched including dynamical calculations of tissue emulsification and ablation, photothermal therapy, and photon transport for photodynamic therapy. This project also enhanced LLNL's core competency in laser-matter interactions and high-energy-density physics by pushing simulation codes into new parameter regimes and by attracting external expertise. This will benefit both existing LLNL programs such as ICF and SBSS and emerging programs in medical technology and other laser applications.

  15. 3D transient model to predict temperature and ablated areas during laser processing of metallic surfaces

    Science.gov (United States)

    Naghshine, Babak. B.; Kiani, Amirkianoosh

    2017-02-01

    Laser processing is one of the most popular small-scale patterning methods and has many applications in semiconductor device fabrication and biomedical engineering. Numerical modelling of this process can be used for better understanding of the process, optimization, and predicting the quality of the final product. An accurate 3D model is presented here for short laser pulses that can predict the ablation depth and temperature distribution on any section of the material in a minimal amount of time. In this transient model, variations of thermal properties, plasma shielding, and phase change are considered. Ablation depth was measured using a 3D optical profiler. Calculated depths are in good agreement with measured values on laser treated titanium surfaces. The proposed model can be applied to a wide range of materials and laser systems.

  16. Multiscale 3D manufacturing: combining thermal extrusion printing with additive and subtractive direct laser writing

    Science.gov (United States)

    Malinauskas, Mangirdas; Lukoševičius, Laurynas; MackevičiÅ«tÄ--, DovilÄ--; BalčiÅ«nas, Evaldas; RekštytÄ--, Sima; Paipulas, Domas

    2014-05-01

    A novel approach for efficient manufacturing of three-dimensional (3D) microstructured scaffolds designed for cell studies and tissue engineering applications is presented. A thermal extrusion (fused filament fabrication) 3D printer is employed as a simple and low-cost tabletop device enabling rapid materialization of CAD models out of biocompatible and biodegradable polylactic acid (PLA). Here it was used to produce cm- scale microporous (pore size varying from 100 to 400 µm) scaffolds. The fabricated objects were further laser processed in a direct laser writing (DLW) subtractive (ablation) and additive (lithography) manners. The first approach enables precise surface modification by creating micro-craters, holes and grooves thus increasing the surface roughness. An alternative way is to immerse the 3D PLA scaffold in a monomer solution and use the same DLW setup to refine its inner structure by fabricating dots, lines or a fine mesh on top as well as inside the pores of previously produced scaffolds. The DLW technique is empowered by ultrafast lasers - it allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. Structure geometry on macro- to micro- scales could be finely tuned by combining these two fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro- featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of ms, microfluidics, microoptics and many others.

  17. Laser micromachining of through via interconnects in active die for 3-D multichip module

    Energy Technology Data Exchange (ETDEWEB)

    Chu, D.; Miller, W.D.

    1995-09-01

    One method to increase density in integrated circuits (IC) is to stack die to create a 3-D multichip module (MCM). In the past, special post wafer processing was done to bring interconnects out to the edge of the die. The die were sawed, glued, and stacked. Special processing was done to create interconnects on the edge to provide for interconnects to each of the die. These processes require an IC type fabrication facility (fab) and special processing equipment. In contrast, we have developed packaging assembly methods to created vertical through vias in bond pads of active silicon die, isolate these vias, and metal fill these vias without the use of a special IC fab. These die with through vias can then be joined and stacked to create a 3-D MCM. Vertical through vias in active die are created by laser micromachining using a Nd:YAG laser. Besides the fundamental 1064 nm (infra-red) laser wavelength of a Nd:YAG laser, modifications to our Nd:YAG laser allowed us to generate the second harmonic 532 nm (green) laser wavelength and fourth harmonic 266nm (ultra violet) laser wavelength in laser micromachining for these vias. Experiments were conducted to determine the best laser wavelengths to use for laser micromachining of vertical through vias in order to minimize damage to the active die. Via isolation experiments were done in order to determine the best method in isolating the bond pads of the die. Die thinning techniques were developed to allow for die thickness as thin as 50 {mu}m. This would allow for high 3-D density when the die are stacked. A method was developed to metal fill the vias with solder using a wire bonder with solder wire.

  18. Ship Maintenance Processes with Collaborative Product Lifecycle Management and 3D Terrestrial Laser Scanning Tools: Reducing Costs and Increasing Productivity

    Science.gov (United States)

    2012-04-30

    approach that incorporates the 3D terrestrial laser scanning (3D TLS) and collaborative product lifecycle management (collab- PLM ) tool suite. Results...incorporated into final implementation of the 3D TLS and collab- PLM tools. 15. SUBJECT TERMS 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF...terrestrial laser scanning (3D TLS) and collaborative product lifecycle management (collab- PLM ) tool suite. Results suggest that when the SHIPMAIN process

  19. Variation in the measurement of cranial volume and surface area using 3D laser scanning technology.

    Science.gov (United States)

    Sholts, Sabrina B; Wärmländer, Sebastian K T S; Flores, Louise M; Miller, Kevin W P; Walker, Phillip L

    2010-07-01

    Three-dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer-generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer-related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.

  20. Sensor Fusion of Cameras and a Laser for City-Scale 3D Reconstruction

    Directory of Open Access Journals (Sweden)

    Yunsu Bok

    2014-11-01

    Full Text Available This paper presents a sensor fusion system of cameras and a 2D laser sensorfor large-scale 3D reconstruction. The proposed system is designed to capture data on afast-moving ground vehicle. The system consists of six cameras and one 2D laser sensor,and they are synchronized by a hardware trigger. Reconstruction of 3D structures is doneby estimating frame-by-frame motion and accumulating vertical laser scans, as in previousworks. However, our approach does not assume near 2D motion, but estimates free motion(including absolute scale in 3D space using both laser data and image features. In orderto avoid the degeneration associated with typical three-point algorithms, we present a newalgorithm that selects 3D points from two frames captured by multiple cameras. The problemof error accumulation is solved by loop closing, not by GPS. The experimental resultsshow that the estimated path is successfully overlaid on the satellite images, such that thereconstruction result is very accurate.

  1. Sensor fusion of cameras and a laser for city-scale 3D reconstruction.

    Science.gov (United States)

    Bok, Yunsu; Choi, Dong-Geol; Kweon, In So

    2014-11-04

    This paper presents a sensor fusion system of cameras and a 2D laser sensorfor large-scale 3D reconstruction. The proposed system is designed to capture data on afast-moving ground vehicle. The system consists of six cameras and one 2D laser sensor,and they are synchronized by a hardware trigger. Reconstruction of 3D structures is doneby estimating frame-by-frame motion and accumulating vertical laser scans, as in previousworks. However, our approach does not assume near 2D motion, but estimates free motion(including absolute scale) in 3D space using both laser data and image features. In orderto avoid the degeneration associated with typical three-point algorithms, we present a newalgorithm that selects 3D points from two frames captured by multiple cameras. The problemof error accumulation is solved by loop closing, not by GPS. The experimental resultsshow that the estimated path is successfully overlaid on the satellite images, such that thereconstruction result is very accurate.

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

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2013-07-01

    Full Text Available scanner technology. A sample of coarse aggregate andesite particles passing 19.0 mm and retained on 13.2 mm sieve was used for the study. The 3-D images from the laser scanning device were fully utilized in quantifying the shape descriptors in order...

  3. Experimental investigation of 3D scanheads for laser micro-processing

    Science.gov (United States)

    Penchev, Pavel; Dimov, Stefan; Bhaduri, Debajyoti

    2016-07-01

    The broader use of laser micro-processing technology increases the demand for executing complex machining and joining operations on free-from (3D) workpieces. To satisfy these growing requirements it is necessary to utilise 3D scanheads that integrate beam deflectors (X and Y optical axes) and Z modules with high dynamics. The research presented in this communication proposes an experimental technique to quantify the dynamic capabilities of Z modules, also called Dynamic Focusing Modules (DFM), of such 3D scanheads that are essential for efficient, accurate and repeatable laser micro-processing of free form surfaces. The proposed experimental technique is validated on state-of-art laser micro-machining platform and the results show that the DFM dynamic capabilities are substantially inferior than those of X and Y beam deflectors, in particular the maximum speed of the Z module is less than 10% of the maximum speeds achievable with X and Y optical axes of the scanhead. Thus, the DFM dynamics deficiencies can become a major obstacle for the broader use of high frequency laser sources that necessitate high dynamics 3D scanheads for executing cost effectively free-form surface processing operations.

  4. Toward 3D Printing of Pure Metals by Laser-Induced Forward Transfer

    NARCIS (Netherlands)

    Visser, Claas Willem; Pohl, Ralph; Sun, Chao; Römer, Gert-Willem; Huis in 't Veld, Bert; Lohse, Detlef

    2015-01-01

    3D printing of common metals is highly challenging because metals are generally solid at room conditions. Copper and gold pillars are manufactured with a resolution below 5 μm and a height up to 2 mm, using laser-induced forward transfer to create and eject liquid metal droplets. The solidified drop

  5. Toward 3D Printing of Pure Metals by Laser-Induced Forward Transfer

    NARCIS (Netherlands)

    Visser, C.W.; Pohl, Ralph; Sun, Chao; Römer, Gerardus Richardus, Bernardus, Engelina; Huis in 't Veld, Bert; Lohse, Detlef

    2015-01-01

    3D printing of common metals is highly challenging because metals are generally solid at room conditions. Copper and gold pillars are manufactured with a resolution below 5 μm and a height up to 2 mm, using laser-induced forward transfer to create and eject liquid metal droplets. The solidified

  6. 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

  7. Inscription of 3D waveguides in diamond using an ultrafast laser

    CERN Document Server

    Courvoisier, Arnaud; Salter, Patrick S

    2016-01-01

    Three dimensional waveguides within the bulk of diamond are manufactured using ultrafast laser fabrication. High intensities within the focal volume of the laser cause breakdown of the diamond into a graphitic phase leading to a stress induced refractive index change in neighboring regions. Type II waveguiding is thus enabled between two adjacent graphitic tracks, but supporting just a single polarization state. We show that adaptive aberration correction during the laser processing allows the controlled fabrication of more complex structures beneath the surface of the diamond which can be used for 3D waveguide splitters and Type III waveguides which support both polarizations.

  8. Inscription of 3D waveguides in diamond using an ultrafast laser

    Science.gov (United States)

    Courvoisier, Arnaud; Booth, Martin J.; Salter, Patrick S.

    2016-07-01

    Three dimensional waveguides within the bulk of diamond are manufactured using ultrafast laser fabrication. High intensities within the focal volume of the laser cause breakdown of the diamond into a graphitic phase leading to a stress induced refractive index change in neighboring regions. Type II waveguiding is thus enabled between two adjacent graphitic tracks, but supporting just a single polarization state. We show that adaptive aberration correction during the laser processing allows the controlled fabrication of more complex structures beneath the surface of the diamond which can be used for 3D waveguide splitters and Type III waveguides which support both polarizations.

  9. Reliability of a 3D surface laser scanner for orthodontic applications.

    Science.gov (United States)

    Kusnoto, Budi; Evans, Carla A

    2002-10-01

    A device for recreating three-dimensional (3D) objects on a computer is the surface laser scanner. By triangulating distances between the reflecting laser beam and the scanned surface, the surface laser scanner can detect not only an object's length and width but also its depth. The scanner's ease of use has opened various possibilities in laboratory research and clinical investigation. We assessed the reliability of generating 3D object reconstructions using the Minolta Vivid700 3D surface laser scanner (Minolta USA, Ramsey, NJ). Accuracy and reproducibility were tested on a geometrical calibrated cylinder, a dental study model, and a plaster facial model. Tests were conducted at varying distances between the object and the scanner. It was found that (1) in the calibrated cylinder tests, spatial distance measurement was accurate to 0.5 mm (+/- 0.1 mm) in the vertical dimension and 0.3 mm (+/- 0.3 mm) in the horizontal dimension; (2) in the study model test, molar width was accurate to 0.2 mm (+/- 0.1 mm, P >.05), and palatal vault depth could be measured to 0.7 mm (+/- 0.2 mm, P > 0.05); and (3) for the facial model, an accuracy of 1.9 +/- 0.8 mm was obtained. The findings suggest that the surface laser scanner has great research potential because of its accuracy and ease of use. Treatment changes, growth, surgical simulations, and many other orthodontic applications can be approached 3-dimensionally with this device.

  10. Rapid 3D video/laser sensing and digital archiving with immediate on-scene feedback for 3D crime scene/mass disaster data collection and reconstruction

    Science.gov (United States)

    Altschuler, Bruce R.; Oliver, William R.; Altschuler, Martin D.

    1996-02-01

    We describe a system for rapid and convenient video data acquisition and 3-D numerical coordinate data calculation able to provide precise 3-D topographical maps and 3-D archival data sufficient to reconstruct a 3-D virtual reality display of a crime scene or mass disaster area. Under a joint U.S. army/U.S. Air Force project with collateral U.S. Navy support, to create a 3-D surgical robotic inspection device -- a mobile, multi-sensor robotic surgical assistant to aid the surgeon in diagnosis, continual surveillance of patient condition, and robotic surgical telemedicine of combat casualties -- the technology is being perfected for remote, non-destructive, quantitative 3-D mapping of objects of varied sizes. This technology is being advanced with hyper-speed parallel video technology and compact, very fast laser electro-optics, such that the acquisition of 3-D surface map data will shortly be acquired within the time frame of conventional 2-D video. With simple field-capable calibration, and mobile or portable platforms, the crime scene investigator could set up and survey the entire crime scene, or portions of it at high resolution, with almost the simplicity and speed of video or still photography. The survey apparatus would record relative position, location, and instantly archive thousands of artifacts at the site with 3-D data points capable of creating unbiased virtual reality reconstructions, or actual physical replicas, for the investigators, prosecutors, and jury.

  11. Femtosecond Laser 3D Fabrication in Porous Glass for Micro- and Nanofluidic Applications

    Directory of Open Access Journals (Sweden)

    Yang Liao

    2014-11-01

    Full Text Available The creation of complex three-dimensional (3D fluidic systems composed of hollow micro- and nanostructures embedded in transparent substrates has attracted significant attention from both scientific and applied research communities. However, it is by now still a formidable challenge to build 3D micro- and nanofluidic structures with arbitrary configurations using conventional planar lithographic fabrication methods. As a direct and maskless fabrication technique, femtosecond laser micromachining provides a straightforward approach for high-precision, spatially-selective, modification inside transparent materials through nonlinear optical absorption. In this paper, we demonstrate rapid fabrication of high-aspect-ratio micro- and/or nanofluidic structures with various 3D configurations by femtosecond laser direct writing in porous glass substrates. Based on this approach, we demonstrate several functional micro- and nanofluidic devices including a 3D passive microfluidic mixer, a capillary electrophoresis (CE analysis chip, and an integrated micro-nanofluidic system for single DNA analysis. The possible mechanisms behind the formation of high-aspect-ratio micro- and nanochannels are also discussed. This technology offers new opportunities to develop novel 3D micro-nanofluidic systems for a variety of lab-on-a-chip applications.

  12. The 3D scanner prototype utilize object profile imaging using line laser and octave software

    Science.gov (United States)

    Nurdini, Mugi; Manunggal, Trikarsa Tirtadwipa; Samsi, Agus

    2016-11-01

    Three-dimensional scanner or 3D Scanner is a device to reconstruct the real object into digital form on a computer. 3D Scanner is a technology that is being developed, especially in developed countries, where the current 3D Scanner devices is the advanced version with a very expensive prices. This study is basically a simple prototype of 3D Scanner with a very low investment costs. 3D Scanner prototype device consists of a webcam, a rotating desk system controlled by a stepper motor and Arduino UNO, and a line laser. Objects that limit the research is the object with same radius from its center point (object pivot). Scanning is performed by using object profile imaging by line laser which is then captured by the camera and processed by a computer (image processing) using Octave software. On each image acquisition, the scanned object on a rotating desk rotated by a certain degree, so for one full turn multiple images of a number of existing side are finally obtained. Then, the profile of the entire images is extracted in order to obtain digital object dimension. Digital dimension is calibrated by length standard, called gage block. Overall dimensions are then digitally reconstructed into a three-dimensional object. Validation of the scanned object reconstruction of the original object dimensions expressed as a percentage error. Based on the results of data validation, horizontal dimension error is about 5% to 23% and vertical dimension error is about +/- 3%.

  13. 3-D reconstruction of neurons from multichannel confocal laser scanning image series.

    Science.gov (United States)

    Wouterlood, Floris G

    2014-04-10

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

  14. 3-D transient numerical simulation on the process of laser cladding by powder feeding

    Institute of Scientific and Technical Information of China (English)

    Yanlu Huang; Gongying Liang; Junyi Su

    2004-01-01

    A 3-D transient mathematical model for laser cladding by powder feeding was developed to examine the macroscopic heat and momentum transport during the process, based on which a novel method for determining the configuration and thickness of cladding layer was presented. By using Lambert-Beer theorem and Mie′s theory, the interaction between powder stream and laser beam was treated to evoke their subtle effects on heat transfer and fluid flow in laser molten pool. The numerical study was performed in a co-ordinate system moving with the laser at a constant scanning speed. A fixed grid enthalpy-porosity approach was used,which predicted the evolutionary development of the laser molten pool. The commercial software PHOENICS, to which several modules were appended, was used to accomplish the simulation. The results obtained by the simulation were coincident with those measured in experiment basically.

  15. A Survey Study of the Blast Furnace at Kuangshan Village Using 3D Laser Scanning

    Science.gov (United States)

    Wang, Jin; Huang, Xing; Qian, Wei

    2017-01-01

    The blast furnace from the Northern Song Dynasty at Kuangshan Village is the tallest blast furnace that remains from ancient China. Previous studies have assumed that the furnace had a closed mouth. In this paper, a three-dimensional (3D) model of the blast furnace is constructed using 3D laser scanning technology, and accurate profile data are obtained using software. It is shown that the furnace throat is smaller than had been previously thought and that the furnace mouth is of the open type. This new furnace profile constitutes a discovery in the history of iron-smelting technology.

  16. Reducing Costs and Increasing Productivity in Ship Maintenance Using Product Lifecycle Management, 3D Laser Scanning and 3D Printing

    Science.gov (United States)

    2014-03-01

    Program, especially RADM James Greene , USN (Ret), Ms. Karey Shaffer, and Ms. Tera Yoder, for providing resources and assistance to ensure the success of...information modeling guide series: 03—GSA BIM guide for 3D imaging (Ver. 1). Retrieved from http://www.gsa.gov/graphics/pbs/GSA_BIM_Guide_Series_03

  17. Laser Welding Analysis for 3D Printed Thermoplastic and Poly-acetate Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Hae Woon; Yun, Sung Chul [Keimyung University, Daegu (Korea, Republic of)

    2015-07-15

    In this study, experimental and computer simulation results are compared and analyzed. Three-dimensional (3D) fabricated matrices from an MJM 3D printer were joined with poly-acetate thermoplastic polymers using a diode laser. A power range of 5-7 W was used to irradiate the boundary of two polymers. The heated polymers flowed into the matrices of the 3D fabricated structure, and reliable mechanical joining was achieved. Computer simulation showed the temperature distribution in the polymers, and flow direction was estimated based on the flux and temperature information. It was found that the more than the minimum energy threshold was required to effectively join the polymers and that two scans at low-speed were more effective than four scans at high speed.

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

    Science.gov (United States)

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

    2017-06-01

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

  19. Laser jetting of femto-liter metal droplets for high resolution 3D printed structures.

    Science.gov (United States)

    Zenou, M; Sa'ar, A; Kotler, Z

    2015-11-25

    Laser induced forward transfer (LIFT) is employed in a special, high accuracy jetting regime, by adequately matching the sub-nanosecond pulse duration to the metal donor layer thickness. Under such conditions, an effective solid nozzle is formed, providing stability and directionality to the femto-liter droplets which are printed from a large gap in excess of 400 μm. We illustrate the wide applicability of this method by printing several 3D metal objects. First, very high aspect ratio (A/R > 20), micron scale, copper pillars in various configuration, upright and arbitrarily bent, then a micron scale 3D object composed of gold and copper. Such a digital printing method could serve the generation of complex, multi-material, micron-scale, 3D materials and novel structures.

  20. Angle extended linear MEMS scanning system for 3D laser vision sensor

    Science.gov (United States)

    Pang, Yajun; Zhang, Yinxin; Yang, Huaidong; Zhu, Pan; Gai, Ye; Zhao, Jian; Huang, Zhanhua

    2016-09-01

    Scanning system is often considered as the most important part for 3D laser vision sensor. In this paper, we propose a method for the optical system design of angle extended linear MEMS scanning system, which has features of huge scanning degree, small beam divergence angle and small spot size for 3D laser vision sensor. The principle of design and theoretical formulas are derived strictly. With the help of software ZEMAX, a linear scanning optical system based on MEMS has been designed. Results show that the designed system can extend scanning angle from ±8° to ±26.5° with a divergence angle small than 3.5 mr, and the spot size is reduced for 4.545 times.

  1. 3D Photonic Nanostructures via Diffusion-Assisted Direct fs Laser Writing

    Directory of Open Access Journals (Sweden)

    Gabija Bickauskaite

    2012-01-01

    Full Text Available We present our research into the fabrication of fully three-dimensional metallic nanostructures using diffusion-assisted direct laser writing, a technique which employs quencher diffusion to fabricate structures with resolution beyond the diffraction limit. We have made dielectric 3D nanostructures by multiphoton polymerization using a metal-binding organic-inorganic hybrid material, and we covered them with silver using selective electroless plating. We have used this method to make spirals and woodpiles with 600 nm intralayer periodicity. The resulting photonic nanostructures have a smooth metallic surface and exhibit well-defined diffraction spectra, indicating good fabrication quality and internal periodicity. In addition, we have made dielectric woodpile structures decorated with gold nanoparticles. Our results show that diffusion-assisted direct laser writing and selective electroless plating can be combined to form a viable route for the fabrication of 3D dielectric and metallic photonic nanostructures.

  2. Development of 3D Chromatin Texture Analysis Using Confocal Laser Scanning Microscopy

    Directory of Open Access Journals (Sweden)

    André Huisman

    2005-01-01

    Full Text Available Introduction: Analysis of nuclear texture features as a measure of nuclear chromatin changes has been proven to be useful when measured on thin (5–6 μm tissue sections using conventional 2D bright field microscopy. The drawback of this approach is that most nuclei are not intact because of those thin sections. Confocal laser scanning microscopy (CLSM allows measurements of texture in 3D reconstructed nuclei. The aim of this study was to develop 3D texture features that quantitatively describe changes in chromatin architecture associated with malignancy using CLSM images. Methods: Thirty-five features thoughtfully chosen from 4 categories of 3D texture features (discrete texture features, Markovian features, fractal features, grey value distribution features were selected and tested for invariance properties (rotation and scaling using artificial images with a known grey value distribution. The discriminative power of the 3D texture features was tested on artificially constructed benign and malignant 3D nuclei with increasing nucleolar size and advancing chromatin margination towards the periphery of the nucleus. As a clinical proof of principle, the discriminative power of the texture features was assessed on 10 benign and 10 malignant human prostate nuclei, evaluating also whether there was more texture information in 3D whole nuclei compared to a single 2D plane from the middle of the nucleus. Results: All texture features showed the expected invariance properties. Almost all features were sensitive to variations in the nucleolar size and to the degree of margination of chromatin. Fourteen texture features from different categories had high discriminative power for separating the benign and malignant nuclei. The discrete texture features performed less than expected. There was more information on nuclear texture in 3D than in 2D. Conclusion: A set of 35 3D nuclear texture features was used successfully to assess nuclear chromatin patterns

  3. Fine Surveying and 3D Modeling Approach for Wooden Ancient Architecture via Multiple Laser Scanner Integration

    Directory of Open Access Journals (Sweden)

    Qingwu Hu

    2016-03-01

    Full Text Available A multiple terrestrial laser scanner (TLS integration approach is proposed for the fine surveying and 3D modeling of ancient wooden architecture in an ancient building complex of Wudang Mountains, which is located in very steep surroundings making it difficult to access. Three-level TLS with a scalable measurement distance and accuracy is presented for data collection to compensate for data missed because of mutual sheltering and scanning view limitations. A multi-scale data fusion approach is proposed for data registration and filtering of the different scales and separated 3D data. A point projection algorithm together with point cloud slice tools is designed for fine surveying to generate all types of architecture maps, such as plan drawings, facade drawings, section drawings, and doors and windows drawings. The section drawings together with slicing point cloud are presented for the deformation analysis of the building structure. Along with fine drawings and laser scanning data, the 3D models of the ancient architecture components are built for digital management and visualization. Results show that the proposed approach can achieve fine surveying and 3D documentation of the ancient architecture within 3 mm accuracy. In addition, the defects of scanning view and mutual sheltering can overcome to obtain the complete and exact structure in detail.

  4. 3D printing of gas jet nozzles for laser-plasma accelerators

    Science.gov (United States)

    Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Ta Phuoc, K.; Malka, V.

    2016-07-01

    Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the Salle Jaune terawatt laser at Laboratoire d'Optique Appliquée.

  5. 3D printing of gas jet nozzles for laser-plasma accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Döpp, A.; Guillaume, E.; Thaury, C.; Gautier, J.; Ta Phuoc, K.; Malka, V. [LOA, ENSTA ParisTech, CNRS, École Polytechnique, Université Paris-Saclay, 828 Boulevard des Maréchaux, 91762 Palaiseau Cedex (France)

    2016-07-15

    Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular, it was reported that the appropriate density tailoring can result in improved injection, acceleration, and collimation of laser-accelerated electron beams. To achieve such profiles, innovative target designs are required. For this purpose, we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely, selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the SALLE JAUNE terawatt laser at Laboratoire d’Optique Appliquée.

  6. 3D printing of gas jet nozzles for laser-plasma accelerators

    CERN Document Server

    Döpp, A; Thaury, C; Gautier, J; Phuoc, K Ta; Malka, V

    2016-01-01

    Recent results on laser wakefield acceleration in tailored plasma channels have underlined the importance of controlling the density profile of the gas target. In particular it was reported that appropriate density tailoring can result in improved injection, acceleration and collimation of laser-accelerated electron beams. To achieve such profiles innovative target designs are required. For this purpose we have reviewed the usage of additive layer manufacturing, commonly known as 3D printing, in order to produce gas jet nozzles. Notably we have compared the performance of two industry standard techniques, namely selective laser sintering (SLS) and stereolithography (SLA). Furthermore we have used the common fused deposition modeling (FDM) to reproduce basic gas jet designs and used SLA and SLS for more sophisticated nozzle designs. The nozzles are characterized interferometrically and used for electron acceleration experiments with the Salle Jaune terawatt laser at Laboratoire d'Optique Appliqu\\'ee.

  7. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul;

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  8. Experimental Demonstration of 6-Mode Division Multiplexed NG-PON2: Cost Effective 40 Gbit/s/Spatial-Mode Access Based on 3D Laser Inscribed Photonic Lanterns

    DEFF Research Database (Denmark)

    Asif, Rameez; Hu, Hao; Mitchell, Paul

    We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP......We report the first space-division-multiplexed based symmetric NG-PON2 network by effi- ciently transmitting 40 Gbit/s/spatial-mode. Error free transmission (BER of 10−9 ) is obtained for all the downstream and upstream data tributaries over 1-km 6-spatial-mode FMF without using MIMO DSP...

  9. Combining laser scan and photogrammetry for 3D object modeling using a single digital camera

    Science.gov (United States)

    Xiong, Hanwei; Zhang, Hong; Zhang, Xiangwei

    2009-07-01

    In the fields of industrial design, artistic design and heritage conservation, physical objects are usually digitalized by reverse engineering through some 3D scanning methods. Laser scan and photogrammetry are two main methods to be used. For laser scan, a video camera and a laser source are necessary, and for photogrammetry, a digital still camera with high resolution pixels is indispensable. In some 3D modeling tasks, two methods are often integrated to get satisfactory results. Although many research works have been done on how to combine the results of the two methods, no work has been reported to design an integrated device at low cost. In this paper, a new 3D scan system combining laser scan and photogrammetry using a single consumer digital camera is proposed. Nowadays there are many consumer digital cameras, such as Canon EOS 5D Mark II, they usually have features of more than 10M pixels still photo recording and full 1080p HD movie recording, so a integrated scan system can be designed using such a camera. A square plate glued with coded marks is used to place the 3d objects, and two straight wood rulers also glued with coded marks can be laid on the plate freely. In the photogrammetry module, the coded marks on the plate make up a world coordinate and can be used as control network to calibrate the camera, and the planes of two rulers can also be determined. The feature points of the object and the rough volume representation from the silhouettes can be obtained in this module. In the laser scan module, a hand-held line laser is used to scan the object, and the two straight rulers are used as reference planes to determine the position of the laser. The laser scan results in dense points cloud which can be aligned together automatically through calibrated camera parameters. The final complete digital model is obtained through a new a patchwise energy functional method by fusion of the feature points, rough volume and the dense points cloud. The design

  10. LA CARTOGRAFIA NELLA VALORIZZAZIONE DEI BENI NATURALI E CULTURALI: LE APPLICAZIONI LASER SCANNER 3D

    OpenAIRE

    2012-01-01

    La presente proposta è relativa all’utilizzo dei rilievi Laser Scanner 3D per la valorizzazione dei beni culturali e naturali. Alla base di ogni intervento volto alla valorizzazione dei beni culturali e naturali è fondamentale che ci sia un percorso di conoscenza che non sia solo storico-artistico come accade spesso, ma anche attraverso la conoscenza accurata delle sue caratteristiche (posizione, forma, geometria, materia e colore), dettagli fondamentali per tutelare e valorizz...

  11. Printing Functional 3D Microdevices by Laser-Induced Forward Transfer.

    Science.gov (United States)

    Luo, Jun; Pohl, Ralph; Qi, Lehua; Römer, Gert-Willem; Sun, Chao; Lohse, Detlef; Visser, Claas Willem

    2017-03-01

    Slender, out-of-plane metal microdevices are made in a new spatial domain, by using laser-induced forward transfer (LIFT) of metals. Here, a thermocouple with a thickness of 10 µm and a height of 250 µm, consisting of platinum and gold pillars is demonstrated. Multimaterial LIFT enables manufacturing in the micrometer to millimeter range, i.e., between lithography and other 3D printing technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Laser jetting of femto-liter metal droplets for high resolution 3D printed structures

    OpenAIRE

    Zenou, M.; A. Sa’ar; Kotler, Z.

    2015-01-01

    Laser induced forward transfer (LIFT) is employed in a special, high accuracy jetting regime, by adequately matching the sub-nanosecond pulse duration to the metal donor layer thickness. Under such conditions, an effective solid nozzle is formed, providing stability and directionality to the femto-liter droplets which are printed from a large gap in excess of 400??m. We illustrate the wide applicability of this method by printing several 3D metal objects. First, very high aspect ratio (A/R?>?...

  13. Mobile large scale 3D coordinate measuring system based on network of rotating laser automatic theodolites

    Science.gov (United States)

    Liu, Zhigang; Liu, Zhongzheng; Wu, Jianwei; Xu, Yaozhong

    2010-08-01

    This paper presents a mobile 3D coordinate measuring system for large scale metrology. This system is composed of a network of rotating laser automatic theodolites (N-RLATs) and a portable touch probe. In the N-RLAT system, each RLAT consists of two laser fans which rotate about its own Z axis at a constant speed and scan the whole metrology space. The optical sensors mounted on the portable touch probe receive the sweeping laser fans and generate the corresponding pulse signals, which establish a relationship between rotating angle of laser fan and time, and then the space angle measurement is converted into the corresponding peak time precision measurement of pulse signal. The rotating laser fans are modeled mathematically as a time varying parametrical vector in its local framework. A two steps on-site calibration method for solving the parameters of each RLAT and coordinate transformation among the N-RLATs. The portable probe is composed of optical sensors array with specified geometrical features and a touch point, on which the coordinates of optical sensors is determined by the N-RLATs and the touch point is estimated by solving a non-linear system. A prototype mobile 3D coordinate measuring system is developed and experiment results show its validity.

  14. AN ADAPTIVE APPROACH FOR SEGMENTATION OF 3D LASER POINT CLOUD

    Directory of Open Access Journals (Sweden)

    Z. Lari

    2012-09-01

    Full Text Available Automatic processing and object extraction from 3D laser point cloud is one of the major research topics in the field of photogrammetry. Segmentation is an essential step in the processing of laser point cloud, and the quality of extracted objects from laser data is highly dependent on the validity of the segmentation results. This paper presents a new approach for reliable and efficient segmentation of planar patches from a 3D laser point cloud. In this method, the neighbourhood of each point is firstly established using an adaptive cylinder while considering the local point density and surface trend. This neighbourhood definition has a major effect on the computational accuracy of the segmentation attributes. In order to efficiently cluster planar surfaces and prevent introducing ambiguities, the coordinates of the origin's projection on each point's best fitted plane are used as the clustering attributes. Then, an octree space partitioning method is utilized to detect and extract peaks from the attribute space. Each detected peak represents a specific cluster of points which are located on a distinct planar surface in the object space. Experimental results show the potential and feasibility of applying this method for segmentation of both airborne and terrestrial laser data.

  15. CO2 laser-inscribed low-cost, shortest-period long-period fibre grating in B–Ge co-doped fibre for high-sensitivity strain measurement

    Indian Academy of Sciences (India)

    Smita Chaubey; Sanjay Kher; Jai Kishore; S M Oak

    2014-02-01

    We have developed high sensitivity long-period fibre gratings (LPGs) in B–Ge codoped fibre for strain sensing application. These LPGs are shortest grating period (180 m) LPGs inscribed in B–Ge co-doped fibre using CO2 laser-based grating inscription set-up. Strain sensitivity of 1.77 dB/mε has been obtained for attenuation band corresponding to the turnaround point mode. TAP operation of LPG facilitates intensity-based detection using simple optical power meter instead of wavelength-based detection.

  16. 3D indoor modeling using a hand-held embedded system with multiple laser range scanners

    Science.gov (United States)

    Hu, Shaoxing; Wang, Duhu; Xu, Shike

    2016-10-01

    Accurate three-dimensional perception is a key technology for many engineering applications, including mobile mapping, obstacle detection and virtual reality. In this article, we present a hand-held embedded system designed for constructing 3D representation of structured indoor environments. Different from traditional vehicle-borne mobile mapping methods, the system presented here is capable of efficiently acquiring 3D data while an operator carrying the device traverses through the site. It consists of a simultaneous localization and mapping(SLAM) module, a 3D attitude estimate module and a point cloud processing module. The SLAM is based on a scan matching approach using a modern LIDAR system, and the 3D attitude estimate is generated by a navigation filter using inertial sensors. The hardware comprises three 2D time-flight laser range finders and an inertial measurement unit(IMU). All the sensors are rigidly mounted on a body frame. The algorithms are developed on the frame of robot operating system(ROS). The 3D model is constructed using the point cloud library(PCL). Multiple datasets have shown robust performance of the presented system in indoor scenarios.

  17. 3-D Laser-Based Multiclass and Multiview Object Detection in Cluttered Indoor Scenes.

    Science.gov (United States)

    Zhang, Xuesong; Zhuang, Yan; Hu, Huosheng; Wang, Wei

    2017-01-01

    This paper investigates the problem of multiclass and multiview 3-D object detection for service robots operating in a cluttered indoor environment. A novel 3-D object detection system using laser point clouds is proposed to deal with cluttered indoor scenes with a fewer and imbalanced training data. Raw 3-D point clouds are first transformed to 2-D bearing angle images to reduce the computational cost, and then jointly trained multiple object detectors are deployed to perform the multiclass and multiview 3-D object detection. The reclassification technique is utilized on each detected low confidence bounding box in the system to reduce false alarms in the detection. The RUS-SMOTEboost algorithm is used to train a group of independent binary classifiers with imbalanced training data. Dense histograms of oriented gradients and local binary pattern features are combined as a feature set for the reclassification task. Based on the dalian university of technology (DUT)-3-D data set taken from various office and household environments, experimental results show the validity and good performance of the proposed method.

  18. Estimation of line dimensions in 3D direct laser writing lithography

    Science.gov (United States)

    Guney, M. G.; Fedder, G. K.

    2016-10-01

    Two photon polymerization (TPP) based 3D direct laser writing (3D-DLW) finds application in a wide range of research areas ranging from photonic and mechanical metamaterials to micro-devices. Most common structures are either single lines or formed by a set of interconnected lines as in the case of crystals. In order to increase the fidelity of these structures and reach the ultimate resolution, the laser power and scan speed used in the writing process should be chosen carefully. However, the optimization of these writing parameters is an iterative and time consuming process in the absence of a model for the estimation of line dimensions. To this end, we report a semi-empirical analytic model through simulations and fitting, and demonstrate that it can be used for estimating the line dimensions mostly within one standard deviation of the average values over a wide range of laser power and scan speed combinations. The model delimits the trend in onset of micro-explosions in the photoresist due to over-exposure and of low degree of conversion due to under-exposure. The model guides setting of high-fidelity and robust writing parameters of a photonic crystal structure without iteration and in close agreement with the estimated line dimensions. The proposed methodology is generalizable by adapting the model coefficients to any 3D-DLW setup and corresponding photoresist as a means to estimate the line dimensions for tuning the writing parameters.

  19. Analysis of uncertainty and repeatability of a low-cost 3D laser scanner.

    Science.gov (United States)

    Polo, María-Eugenia; Felicísimo, Angel M

    2012-01-01

    Portable 3D laser scanners are a valuable tool for compiling elaborate digital collections of archaeological objects and analysing the shapes and dimensions of pieces. Although low-cost desktop 3D laser scanners have powerful capacities, it is important to know their limitations. This paper performs an analysis of the uncertainty and repeatability of the NextEngine™ portable low-cost 3D laser scanner by scanning an object 20 times in two different resolution modes-Macro and Wide. Some dimensions of the object were measured using a digital calliper, and these results were used as the "true" or control data. In comparing the true and the scanned data, we verified that the mean uncertainty in the Macro Mode is approximately half that of the Wide Mode, at ± 0.81 mm and ± 1.66 mm, respectively. These experimental results are significantly higher than the accuracy specifications provided by the manufacturer. An analysis of repeatability shows that the successive replicates do not match in the same position. The results are better in Macro Mode than in Wide Mode; it is observed that the repeatability factor is slightly larger than the corresponding mode accuracy, with ± 0.84 vs. ± 0.81 mm in Macro Mode and ± 1.82 vs. ± 1.66 mm in Wide Mode. We suggest several improvements, such as adding an external reference scale or providing a calibrated object to allow for a self-calibration operation of the scanner.

  20. The Super Gaussian Laser Intensity Profile in HYDRA's 3D Laser Ray Trace Package

    Energy Technology Data Exchange (ETDEWEB)

    Sepke, Scott M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-01-05

    In this note, the laser focal plane intensity pro le for a beam modeled using the 3D ray trace package in HYDRA is determined. First, the analytical model is developed followed by a practical numerical model for evaluating the resulting computationally intensive normalization factor for all possible input parameters.

  1. Laser processes and analytics for high power 3D battery materials

    Science.gov (United States)

    Pfleging, W.; Zheng, Y.; Mangang, M.; Bruns, M.; Smyrek, P.

    2016-03-01

    Laser processes for cutting, modification and structuring of energy storage materials such as electrodes, separator materials and current collectors have a great potential in order to minimize the fabrication costs and to increase the performance and operational lifetime of high power lithium-ion-batteries applicable for stand-alone electric energy storage devices and electric vehicles. Laser direct patterning of battery materials enable a rather new technical approach in order to adjust 3D surface architectures and porosity of composite electrode materials such as LiCoO2, LiMn2O4, LiFePO4, Li(NiMnCo)O2, and Silicon. The architecture design, the increase of active surface area, and the porosity of electrodes or separator layers can be controlled by laser processes and it was shown that a huge impact on electrolyte wetting, lithium-ion diffusion kinetics, cell life-time and cycling stability can be achieved. In general, the ultrafast laser processing can be used for precise surface texturing of battery materials. Nevertheless, regarding cost-efficient production also nanosecond laser material processing can be successfully applied for selected types of energy storage materials. A new concept for an advanced battery manufacturing including laser materials processing is presented. For developing an optimized 3D architecture for high power composite thick film electrodes electrochemical analytics and post mortem analytics using laser-induced breakdown spectroscopy were performed. Based on mapping of lithium in composite electrodes, an analytical approach for studying chemical degradation in structured and unstructured lithium-ion batteries will be presented.

  2. Precision-guided surgical navigation system using laser guidance and 3D autostereoscopic image overlay.

    Science.gov (United States)

    Liao, Hongen; Ishihara, Hirotaka; Tran, Huy Hoang; Masamune, Ken; Sakuma, Ichiro; Dohi, Takeyoshi

    2010-01-01

    This paper describes a precision-guided surgical navigation system for minimally invasive surgery. The system combines a laser guidance technique with a three-dimensional (3D) autostereoscopic image overlay technique. Images of surgical anatomic structures superimposed onto the patient are created by employing an animated imaging method called integral videography (IV), which can display geometrically accurate 3D autostereoscopic images and reproduce motion parallax without the need for special viewing or tracking devices. To improve the placement accuracy of surgical instruments, we integrated an image overlay system with a laser guidance system for alignment of the surgical instrument and better visualization of patient's internal structure. We fabricated a laser guidance device and mounted it on an IV image overlay device. Experimental evaluations showed that the system could guide a linear surgical instrument toward a target with an average error of 2.48 mm and standard deviation of 1.76 mm. Further improvement to the design of the laser guidance device and the patient-image registration procedure of the IV image overlay will make this system practical; its use would increase surgical accuracy and reduce invasiveness.

  3. Active optical system for advanced 3D surface structuring by laser remelting

    Science.gov (United States)

    Pütsch, O.; Temmler, A.; Stollenwerk, J.; Willenborg, E.; Loosen, P.

    2015-03-01

    Structuring by laser remelting enables completely new possibilities for designing surfaces since material is redistributed but not wasted. In addition to technological advantages, cost and time benefits yield from shortened process times, the avoidance of harmful chemicals and the elimination of subsequent finishing steps such as cleaning and polishing. The functional principle requires a completely new optical machine technology that maintains the spatial and temporal superposition and manipulation of three different laser beams emitted from two laser sources of different wavelength. The optical system has already been developed and demonstrated for the processing of flat samples of hot and cold working steel. However, since particularly the structuring of 3D-injection molds represents an application example of high innovation potential, the optical system has to take into account the elliptical beam geometry that occurs when the laser beams irradiate a curved surface. To take full advantage of structuring by remelting for the processing of 3D surfaces, additional optical functionality, called EPS (elliptical pre-shaping) has to be integrated into the existing set-up. The development of the beam shaping devices not only requires the analysis of the mechanisms of the beam projection but also a suitable optical design. Both aspects are discussed in this paper.

  4. Long-range laser scanning and 3D imaging for the Gneiss quarries survey

    Science.gov (United States)

    Schenker, Filippo Luca; Spataro, Alessio; Pozzoni, Maurizio; Ambrosi, Christian; Cannata, Massimiliano; Günther, Felix; Corboud, Federico

    2016-04-01

    In Canton Ticino (Southern Switzerland), the exploitation of natural stone, mostly gneisses, is an important activity of valley's economies. Nowadays, these economic activities are menaced by (i) the exploitation costs related to geological phenomena such as fractures, faults and heterogeneous rocks that hinder the processing of the stone product, (ii) continuously changing demand because of the evolving natural stone fashion and (iii) increasing administrative limits and rules acting to protect the environment. Therefore, the sustainable development of the sector for the next decades needs new and effective strategies to regulate and plan the quarries. A fundamental step in this process is the building of a 3D geological model of the quarries to constrain the volume of commercial natural stone and the volume of waste. In this context, we conducted Terrestrial Laser Scanning surveys of the quarries in the Maggia Valley to obtain a detailed 3D topography onto which the geological units were mapped. The topographic 3D model was obtained with a long-range laser scanning Riegl VZ4000 that can measure from up to 4 km of distance with a speed of 147,000 points per second. It operates with the new V-line technology, which defines the surface relief by sensing differentiated signals (echoes), even in the presence of obstacles such as vegetation. Depending on the esthetics of the gneisses, we defined seven types of natural stones that, together with faults and joints, were mapped onto the 3D models of the exploitation sites. According to the orientation of the geological limits and structures, we projected the different rock units and fractures into the excavation front. This way, we obtained a 3D geological model from which we can quantitatively estimate the volume of the seven different natural stones (with different commercial value) and waste (with low commercial value). To verify the 3D geological models and to quantify exploited rock and waste volumes the same

  5. Lorentz boosted frame simulation of Laser wakefield acceleration in quasi-3D geometry

    CERN Document Server

    Yu, Peicheng; Davidson, Asher; Tableman, Adam; Dalichaouch, Thamine; Meyers, Michael D; Tsung, Frank S; Decyk, Viktor K; Fiuza, Frederico; Vieira, Jorge; Fonseca, Ricardo A; Lu, Wei; Silva, Luis O; Mori, Warren B

    2015-01-01

    When modeling laser wakefield acceleration (LWFA) using the particle-in-cell (PIC) algorithm in a Lorentz boosted frame, the plasma is drifting relativistically at $\\beta_b c$ towards the laser, which can lead to a computational speedup of $\\sim \\gamma_b^2=(1-\\beta_b^2)^{-1}$. Meanwhile, when LWFA is modeled in the quasi-3D geometry in which the electromagnetic fields and current are decomposed into a limited number of azimuthal harmonics, speedups are achieved by modeling three dimensional problems with the computation load on the order of two dimensional $r-z$ simulations. Here, we describe how to combine the speed ups from the Lorentz boosted frame and quasi-3D algorithms. The key to the combination is the use of a hybrid Yee-FFT solver in the quasi-3D geometry that can be used to effectively eliminate the Numerical Cerenkov Instability (NCI) that inevitably arises in a Lorentz boosted frame due to the unphysical coupling of Langmuir modes and EM modes of the relativistically drifting plasma in these simul...

  6. Geoarchaeological site documentation and analysis of 3D data derived by terrestrial laser scanning

    Science.gov (United States)

    Hoffmeister, D.; Zellmann, S.; Kindermann, K.; Pastoors, A.; Lang, U.; Bubenzer, O.; Weniger, G.-C.; Bareth, G.

    2014-05-01

    Terrestrial laser scanning was conducted to document and analyse sites of geoarchaeological interest in Jordan, Egypt and Spain. In those cases, the terrestrial laser scanner LMS-Z420i from Riegl was used in combination with an accurate RTK-GPS for georeferencing of the point clouds. Additionally, local surveying networks were integrated by established transformations and used for indirect registration purposes. All data were integrated in a workflow that involves different software and according results. The derived data were used for the documentation of the sites by accurate plans and cross-sections. Furthermore, the 3D data were analysed for geoarchaeological research problems, such as volumetric determinations, the ceiling thickness of a cave and lighting simulations based on path tracing. The method was reliable in harsh environmental conditions, but the weight of the instrument, the measuring time and the minimum measurement distance were a drawback. However, generally an accurate documentation of the sites was possible. Overall, the integration in a 3D GIS is easily possible by the accurate georeference of the derived data. In addition, local survey results are also implemented by the established transformations. Enhanced analyses based on the derived 3D data shows promising results.

  7. Topographical surveys: Classical method versus 3D laser scanning. Case study - An application in civil engineering

    Science.gov (United States)

    Grigoraş, I.-R.; Covăsnianu, A.; Pleşu, G.; Benedict, B.

    2009-04-01

    The paper describes an experiment which took place in Iasi town, Romania, consisted in two different topographical survey techniques applied for one and the same objective placed in a block within the city (western part) - a thermal power station. The purpose was to compare those methods and to determine which one is proper to be used in this domain in terms of fastness, optimization and speed of data processing. First technique applied for our survey was the classical one, with a total station. Using the CAD technique, we obtained a final product (a dwg file) and a list of coordinates (a text file). The second method, which we focused our attention more, was the measurement with a very precise 3D laser scanstation, also very suitable in archeology. The data obtained were processed with special software. Result was a 3D model of the thermal power plant composed of measurable cloud point data. Finally, analyzing the advantages and disadvantages of each method, we came to the conclusion that the 3D laser scanning which we used matches well the application, in this case civil engineering, but the future of accepting and implementing this technique is in the hands of Romanian authorities.

  8. Full Waveform Analysis for Long-Range 3D Imaging Laser Radar

    Directory of Open Access Journals (Sweden)

    Wallace AndrewM

    2010-01-01

    Full Text Available The new generation of 3D imaging systems based on laser radar (ladar offers significant advantages in defense and security applications. In particular, it is possible to retrieve 3D shape information directly from the scene and separate a target from background or foreground clutter by extracting a narrow depth range from the field of view by range gating, either in the sensor or by postprocessing. We discuss and demonstrate the applicability of full-waveform ladar to produce multilayer 3D imagery, in which each pixel produces a complex temporal response that describes the scene structure. Such complexity caused by multiple and distributed reflection arises in many relevant scenarios, for example in viewing partially occluded targets, through semitransparent materials (e.g., windows and through distributed reflective media such as foliage. We demonstrate our methodology on 3D image data acquired by a scanning time-of-flight system, developed in our own laboratories, which uses the time-correlated single-photon counting technique.

  9. 3D Microporous Scaffolds Manufactured via Combination of Fused Filament Fabrication and Direct Laser Writing Ablation

    Directory of Open Access Journals (Sweden)

    Mangirdas Malinauskas

    2014-09-01

    Full Text Available A 3D printing fused filament fabrication (FFF approach has been implemented for the creation of microstructures having an internal 3D microstructure geometry. These objects were produced without any sacrificial structures or additional support materials, just by precisely tuning the nozzle heating, fan cooling and translation velocity parameters. The manufactured microporous structures out of polylactic acid (PLA had fully controllable porosity (20%–60% and consisted of desired volume pores (~0.056 μm3. The prepared scaffolds showed biocompatibility and were suitable for the primary stem cell growth. In addition, direct laser writing (DLW ablation was employed to modify the surfaces of the PLA structures, drill holes, as well as shape the outer geometries of the created objects. The proposed combination of FFF printing with DLW offers successful fabrication of 3D microporous structures with functionalization capabilities, such as the modification of surfaces, the generation of grooves and microholes and cutting out precisely shaped structures (micro-arrows, micro-gears. The produced structures could serve as biomedical templates for cell culturing, as well as biodegradable implants for tissue engineering. The additional micro-architecture is important in connection with the cell types used for the intention of cell growing. Moreover, we show that surface roughness can be modified at the nanoscale by immersion into an acetone bath, thus increasing the hydrophilicity. The approach is not limited to biomedical applications, it could be employed for the manufacturing of bioresorbable 3D microfluidic and micromechanic structures.

  10. Development of a 3D modeling algorithm for tunnel deformation monitoring based on terrestrial laser scanning

    Directory of Open Access Journals (Sweden)

    Xiongyao Xie

    2017-03-01

    Full Text Available Deformation monitoring is vital for tunnel engineering. Traditional monitoring techniques measure only a few data points, which is insufficient to understand the deformation of the entire tunnel. Terrestrial Laser Scanning (TLS is a newly developed technique that can collect thousands of data points in a few minutes, with promising applications to tunnel deformation monitoring. The raw point cloud collected from TLS cannot display tunnel deformation; therefore, a new 3D modeling algorithm was developed for this purpose. The 3D modeling algorithm includes modules for preprocessing the point cloud, extracting the tunnel axis, performing coordinate transformations, performing noise reduction and generating the 3D model. Measurement results from TLS were compared to the results of total station and numerical simulation, confirming the reliability of TLS for tunnel deformation monitoring. Finally, a case study of the Shanghai West Changjiang Road tunnel is introduced, where TLS was applied to measure shield tunnel deformation over multiple sections. Settlement, segment dislocation and cross section convergence were measured and visualized using the proposed 3D modeling algorithm.

  11. Simultaneous Wood Defect and Species Detection with 3D Laser Scanning Scheme

    Directory of Open Access Journals (Sweden)

    Zhao Peng

    2016-01-01

    Full Text Available Wood grading and wood price are mainly connected with the wood defect and wood species. In this paper, a wood defect quantitative detection scheme and a wood species qualitative identification scheme are proposed simultaneously based on 3D laser scanning point cloud. First, an Artec 3D scanner is used to scan the wood surface to get the 3D point cloud. Each 3D point contains its X, Y, and Z coordinate and its RGB color information. After preprocessing, the Z coordinate value of current point is compared with the set threshold to judge whether it is a defect point (i.e., cavity, worm tunnel, and crack. Second, a deep preferred search algorithm is used to segment the retained defect points marked with different colors. The integration algorithm is used to calculate the surface area and volume of every defect. Finally, wood species identification is performed with the wood surface’s color information. The color moments of scanned points are used for classification, but the defect points are not used. Experiments indicate that our scheme can accurately measure the surface areas and volumes of cavity, worm tunnel, and crack on wood surface with measurement error less than 5% and it can also reach a wood species recognition accuracy of 95%.

  12. Grammar-based Automatic 3D Model Reconstruction from Terrestrial Laser Scanning Data

    Science.gov (United States)

    Yu, Q.; Helmholz, P.; Belton, D.; West, G.

    2014-04-01

    The automatic reconstruction of 3D buildings has been an important research topic during the last years. In this paper, a novel method is proposed to automatically reconstruct the 3D building models from segmented data based on pre-defined formal grammar and rules. Such segmented data can be extracted e.g. from terrestrial or mobile laser scanning devices. Two steps are considered in detail. The first step is to transform the segmented data into 3D shapes, for instance using the DXF (Drawing Exchange Format) format which is a CAD data file format used for data interchange between AutoCAD and other program. Second, we develop a formal grammar to describe the building model structure and integrate the pre-defined grammars into the reconstruction process. Depending on the different segmented data, the selected grammar and rules are applied to drive the reconstruction process in an automatic manner. Compared with other existing approaches, our proposed method allows the model reconstruction directly from 3D shapes and takes the whole building into account.

  13. Laser irradiated fluorescent perfluorocarbon microparticles in 2-D and 3-D breast cancer cell models

    Science.gov (United States)

    Niu, Chengcheng; Wang, Long; Wang, Zhigang; Xu, Yan; Hu, Yihe; Peng, Qinghai

    2017-03-01

    Perfluorocarbon (PFC) droplets were studied as new generation ultrasound contrast agents via acoustic or optical droplet vaporization (ADV or ODV). Little is known about the ODV irradiated vaporization mechanisms of PFC-microparticle complexs and the stability of the new bubbles produced. In this study, fluorescent perfluorohexane (PFH) poly(lactic-co-glycolic acid) (PLGA) particles were used as a model to study the process of particle vaporization and bubble stability following excitation in two-dimensional (2-D) and three-dimensional (3-D) cell models. We observed localization of the fluorescent agent on the microparticle coating material initially and after vaporization under fluorescence microscopy. Furthermore, the stability and growth dynamics of the newly created bubbles were observed for 11 min following vaporization. The particles were co-cultured with 2-D cells to form 3-D spheroids and could be vaporized even when encapsulated within the spheroids via laser irradiation, which provides an effective basis for further work.

  14. Creating stable Floquet-Weyl semimetals by laser-driving of 3D Dirac materials

    Science.gov (United States)

    Hübener, Hannes; Sentef, Michael A.; de Giovannini, Umberto; Kemper, Alexander F.; Rubio, Angel

    2017-01-01

    Tuning and stabilizing topological states, such as Weyl semimetals, Dirac semimetals or topological insulators, is emerging as one of the major topics in materials science. Periodic driving of many-body systems offers a platform to design Floquet states of matter with tunable electronic properties on ultrafast timescales. Here we show by first principles calculations how femtosecond laser pulses with circularly polarized light can be used to switch between Weyl semimetal, Dirac semimetal and topological insulator states in a prototypical three-dimensional (3D) Dirac material, Na3Bi. Our findings are general and apply to any 3D Dirac semimetal. We discuss the concept of time-dependent bands and steering of Floquet-Weyl points and demonstrate how light can enhance topological protection against lattice perturbations. This work has potential practical implications for the ultrafast switching of materials properties, such as optical band gaps or anomalous magnetoresistance.

  15. 3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy

    Science.gov (United States)

    Gimenez, Y.; Busser, B.; Trichard, F.; Kulesza, A.; Laurent, J. M.; Zaun, V.; Lux, F.; Benoit, J. M.; Panczer, G.; Dugourd, P.; Tillement, O.; Pelascini, F.; Sancey, L.; Motto-Ros, V.

    2016-07-01

    Nanomaterials represent a rapidly expanding area of research with huge potential for future medical applications. Nanotechnology indeed promises to revolutionize diagnostics, drug delivery, gene therapy, and many other areas of research. For any biological investigation involving nanomaterials, it is crucial to study the behavior of such nano-objects within tissues to evaluate both their efficacy and their toxicity. Here, we provide the first account of 3D label-free nanoparticle imaging at the entire-organ scale. The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy. We then used two different but complementary approaches to achieve 3D elemental imaging with LIBS: a volume reconstruction of a sliced organ and in-depth analysis. This proof-of-concept study demonstrates the quantitative imaging of both endogenous and exogenous elements within entire organs and paves the way for innumerable applications.

  16. Development of scanning laser sensor for underwater 3D imaging with the coaxial optics

    Science.gov (United States)

    Ochimizu, Hideaki; Imaki, Masaharu; Kameyama, Shumpei; Saito, Takashi; Ishibashi, Shoujirou; Yoshida, Hiroshi

    2014-06-01

    We have developed the scanning laser sensor for underwater 3-D imaging which has the wide scanning angle of 120º (Horizontal) x 30º (Vertical) with the compact size of 25 cm diameter and 60 cm long. Our system has a dome lens and a coaxial optics to realize both the wide scanning angle and the compactness. The system also has the feature in the sensitivity time control (STC) circuit, in which the receiving gain is increased according to the time of flight. The STC circuit contributes to detect a small signal by suppressing the unwanted signals backscattered by marine snows. We demonstrated the system performance in the pool, and confirmed the 3-D imaging with the distance of 20 m. Furthermore, the system was mounted on the autonomous underwater vehicle (AUV), and demonstrated the seafloor mapping at the depth of 100 m in the ocean.

  17. Creating stable Floquet–Weyl semimetals by laser-driving of 3D Dirac materials

    Science.gov (United States)

    Hübener, Hannes; Sentef, Michael A.; De Giovannini, Umberto; Kemper, Alexander F.; Rubio, Angel

    2017-01-01

    Tuning and stabilizing topological states, such as Weyl semimetals, Dirac semimetals or topological insulators, is emerging as one of the major topics in materials science. Periodic driving of many-body systems offers a platform to design Floquet states of matter with tunable electronic properties on ultrafast timescales. Here we show by first principles calculations how femtosecond laser pulses with circularly polarized light can be used to switch between Weyl semimetal, Dirac semimetal and topological insulator states in a prototypical three-dimensional (3D) Dirac material, Na3Bi. Our findings are general and apply to any 3D Dirac semimetal. We discuss the concept of time-dependent bands and steering of Floquet–Weyl points and demonstrate how light can enhance topological protection against lattice perturbations. This work has potential practical implications for the ultrafast switching of materials properties, such as optical band gaps or anomalous magnetoresistance. PMID:28094286

  18. Cladding waveguide gratings in standard single-mode fiber for 3D shape sensing.

    Science.gov (United States)

    Waltermann, Christian; Doering, Alexander; Köhring, Michael; Angelmahr, Martin; Schade, Wolfgang

    2015-07-01

    Femtosecond laser pulses were used for the direct point-by-point inscription of waveguides into the cladding of standard single-mode fibers. Homogeneous S-shaped waveguides have been processed as a bundle of overlapping lines without damaging the surrounding material. Within these structures, FBGs have been successfully inscribed and characterized. A sensor device to measure the bending direction of a fiber was created by two perpendicular inscribed cladding waveguides with FBG. Finally, a complete 3D shape sensor consisting of several bending sensor planes, capable of detecting bending radii even below 2.5 cm is demonstrated.

  19. 3-D patterning of silicon by laser-initiated, liquid-assisted colloidal (LILAC) lithography.

    Science.gov (United States)

    Ulmeanu, M; Grubb, M P; Jipa, F; Quignon, B; Ashfold, M N R

    2015-06-01

    We report a comprehensive study of laser-initiated, liquid-assisted colloidal (LILAC) lithography, and illustrate its utility in patterning silicon substrates. The method combines single shot laser irradiation (frequency doubled Ti-sapphire laser, 50fs pulse duration, 400nm wavelength) and medium-tuned optical near-field effects around arrays of silica colloidal particles to achieve 3-D surface patterning of silicon. A monolayer (or multilayers) of hexagonal close packed silica colloidal particles act as a mask and offer a route to liquid-tuned optical near field enhancement effects. The resulting patterns are shown to depend on the difference in refractive index of the colloidal particles (ncolloid) and the liquid (nliquid) in which they are immersed. Two different topographies are demonstrated experimentally: (a) arrays of bumps, centred beneath the original colloidal particles, when using liquids with nliquidncolloid - and explained with the aid of complementary Mie scattering simulations. The LILAC lithography technique has potential for rapid, large area, organized 3-D patterning of silicon (and related) substrates. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Laser and beta source setup characterization of 3D-DDTC detectors fabricated at FBK-irst

    Energy Technology Data Exchange (ETDEWEB)

    Zoboli, A. [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38050 Povo (Trento) (Italy)], E-mail: zoboli@disi.unitn.it; Dalla Betta, G.-F. [INFN, Sezione di Padova (Gruppo Collegato di Trento), and Dipartimento di Ingegneria e Scienza dell' Informazione, Universita di Trento, Via Sommarive, 14, I-38050 Povo (Trento) (Italy); Boscardin, M. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38050 Povo (Trento) (Italy); Bosisio, L. [Dip. di Fisica e INFN, Universita di Trieste, I-34127, Trieste (Italy); Eckert, S.; Kuehn, S.; Parzefall, U. [Institute of Physics, University of Freiburg, Hermann-Herder-Str. 3, 79104 Freiburg (Germany); Piemonte, C.; Ronchin, S.; Zorzi, N. [Fondazione Bruno Kessler, Centro per i Materiali e i Microsistemi, Via Sommarive, 18, I-38050 Povo (Trento) (Italy)

    2009-06-01

    We report on the functional characterization of the first batch of 3D Double-Sided Double Type Column (3D-DDTC) detectors fabricated at FBK, Trento. This detector concept represents the evolution of the previous 3D-STC detectors towards full 3D detectors, and is expected to achieve a performance which is comparable to standard 3D detectors, but with a simpler fabrication process. Measurements were performed on detectors in the microstrip configuration coupled to the ATLAS ABCD3T binary readout. This paper reports spatially resolved signal efficiency tests made with a pulsed infrared laser setup and charge collection efficiency tests made with a Beta source.

  1. Application of a hybrid 3D-2D laser scanning system to the characterization of slate slabs.

    Science.gov (United States)

    López, Marcos; Martínez, Javier; Matías, José María; Vilán, José Antonio; Taboada, Javier

    2010-01-01

    Dimensional control based on 3D laser scanning techniques is widely used in practice. We describe the application of a hybrid 3D-2D laser scanning system to the characterization of slate slabs with structural defects that are difficult for the human eye to characterize objectively. Our study is based on automating the process using a 3D laser scanner and a 2D camera. Our results demonstrate that the application of this hybrid system optimally characterizes slate slabs in terms of the defects described by the Spanish UNE-EN 12326-1 standard.

  2. The Gaussian Laser Angular Distribution in HYDRA's 3D Laser Ray Trace Package

    Energy Technology Data Exchange (ETDEWEB)

    Sepke, Scott M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-04-10

    In this note, the angular distribution of rays launched by the 3D LZR ray trace package is derived for Gaussian beams (npower==2) with bm model=3±. Beams with bm model=+3 have a nearly at distribution, and beams with bm model=-3 have a nearly linear distribution when the spot size is large compared to the wavelength.

  3. Directionality in laser fabrication of 3D graphitic microwires in diamond

    Science.gov (United States)

    Sun, B.; Salter, P. S.; Booth, M. J.

    2016-03-01

    Graphitic wires embedded beneath the surface of single crystal diamond are promising for a variety of applications. Through a combination of ultra short (femtosecond) pulsed fabrication, high numerical aperture focusing and adaptive optics, graphitic wires can be written along any 3D path. Here, we demonstrate a non-reciprocal directional dependence to the graphitization process: the features are distinct when the fabrication direction is reversed. The non-reciprocal effects are significantly determined by the laser power, the fabrication speed, the light polarization and pulse front tilt. The influences of these factors are studied.

  4. Light engine and optics for HELIUM3D auto-stereoscopic laser scanning display

    OpenAIRE

    Aksit, K.; Olcer, S.; Erden, E.; Kishore, V. C.; Urey, H.; Willman, E.; Baghsiahi, H.; Day, S. E.; Selviah, D. R.; Fernandez, F. A.; Surman, P.

    2011-01-01

    This paper presents a laser based auto-stereoscopic 3D display technique and a prototype utilizing a dual projector light engine. The solution described is able to form dynamic exit pupils under the control of a multi-user head-tracker. A prototype completed recently is able to provide a glasses-free solution for a single user at a fixed position. At the end of the prototyping phase it is expected to enable a multiple user interface with an integration of the pupil tracker and the spatial lig...

  5. 3D handheld laser scanner based approach for automatic identification and localization of EEG sensors.

    Science.gov (United States)

    Koessler, Laurent; Cecchin, Thierry; Ternisien, Eric; Maillard, Louis

    2010-01-01

    This paper describes and assesses for the first time the use of a handheld 3D laser scanner for scalp EEG sensor localization and co-registration with magnetic resonance images. Study on five subjects showed that the scanner had an equivalent accuracy, a better repeatability, and was faster than the reference electromagnetic digitizer. According to electrical source imaging, somatosensory evoked potentials experiments validated its ability to give precise sensor localization. With our automatic labeling method, the data provided by the scanner could be directly introduced in the source localization studies.

  6. Scanning cross-correlator for monitoring uniform 3D ellipsoidal laser beams

    CERN Document Server

    Zelenogorskii, V V; Gacheva, E I; Gelikonov, G V; Krasilnikov, M; Mart'yanov, M A; Mironov, S Yu; Potemkin, A K; Syresin, E M; Stephan, F; Khazanov, E A

    2014-01-01

    The specific features of experimental implementation of a cross-correlator with a scan rate above 1600 cm s(-1) and a spatial delay amplitude of more than 15 mm are considered. The possibility of measuring the width of femtosecond pulses propagating in a train 300 mu s in duration with a repetition rate of 1 MHz is demonstrated. A time resolution of 300 fs for the maximum time window of 50 ps is attained.The cross-correlator is aimed at testing 3D pulses of a laser driver of an electron photo-injector.

  7. Global Vegetation 3-D Structure Sampling with Full-Waveform Laser Altimetry

    Science.gov (United States)

    Blair, B.; Ranson, J.; Dubayah, R.; Knox, R.; Imhoff, M.

    2006-12-01

    Waveform-based laser altimetry has been established as an excellent source of vegetation 3-D structure data for assessing above-ground biomass and habitat. Recent efforts to mature the needed laser and waveform digitizer technologies have progressed significantly and a space-based mission would now be considered a medium-low risk venture. A multi-beam lidar system would be able to sufficiently sample global vegetation height and structure to estimate the above-ground biomass at unprecedented accuracy as well as contributing to a variety of other Earth Science goals. We will present the high-level instrument specifications and results of technology maturation and testing efforts. We will also present statistical studies on the global sampling approach and potential fusion with long-wavelength Synthetic Aperture Radar (SAR), and multi-angle and hyperspectral sensors.

  8. Some Experiences in 3D Laser Scanning for Assisting Restoration and Evaluating Damage in Cultural Heritage

    Science.gov (United States)

    Fuentes, L. M.; Finat, Javier; Fernández-Martin, J. J.; Martínez, J.; SanJose, J. I.

    The recent incorporation of laser devices provides advanced tools for assisting the conservation and restoration of Cultural Heritage. It is necessary to have as complete as possible understanding of the object state before evaluating or defining the reach of the restoration process. Thus, a special effort is devoted to surveying, measuring and generating a high-resolution 3D model prior to restoration planning. This work presents results of several experiments performed on damaged pieces for evaluation purposes in Cultural Heritage. Some software tools are applied for carving-work analysis, conservation-state monitoring, and simulation of weathering processes for evaluating temporal changes. In all cases considered, a high resolution information capture has been performed with a laser scanner, the Minolta 910. Our approach is flexible enough to be adapted to other kinds of pieces or Cultural Heritage artefacts, in order to provide an assessment for intervention planning in conservation and restoration tasks.

  9. Novel eye-safe line scanning 3D laser-radar

    Science.gov (United States)

    Eberle, B.; Kern, Tobias; Hammer, Marcus; Schwanke, Ullrich; Nowak, Heinrich

    2014-10-01

    Today, the civil market provides quite a number of different 3D-Sensors covering ranges up to 1 km. Typically these sensors are based on single element detectors which suffer from the drawback of spatial resolution at larger distances. Tasks demanding reliable object classification at long ranges can be fulfilled only by sensors consisting of detector arrays. They ensure sufficient frame rates and high spatial resolution. Worldwide there are many efforts in developing 3D-detectors, based on two-dimensional arrays. This paper presents first results on the performance of a recently developed 3D imaging laser radar sensor, working in the short wave infrared (SWIR) at 1.5 μm. It consists of a novel Cadmium Mercury Telluride (CMT) linear array APD detector with 384x1 elements at a pitch of 25 μm, developed by AIM Infrarot Module GmbH. The APD elements are designed to work in the linear (non-Geiger) mode. Each pixel will provide the time of flight measurement, and, due to the linear detection mode, allowing the detection of three successive echoes. The resolution in depth is 15 cm, the maximum repetition rate is 4 kHz. We discuss various sensor concepts regarding possible applications and their dependence on system parameters like field of view, frame rate, spatial resolution and range of operation.

  10. Error Analysis of Terrestrial Laser Scanning Data by Means of Spherical Statistics and 3D Graphs

    Directory of Open Access Journals (Sweden)

    Pedro Arias

    2010-11-01

    Full Text Available This paper presents a complete analysis of the positional errors of terrestrial laser scanning (TLS data based on spherical statistics and 3D graphs. Spherical statistics are preferred because of the 3D vectorial nature of the spatial error. Error vectors have three metric elements (one module and two angles that were analyzed by spherical statistics. A study case has been presented and discussed in detail. Errors were calculating using 53 check points (CP and CP coordinates were measured by a digitizer with submillimetre accuracy. The positional accuracy was analyzed by both the conventional method (modular errors analysis and the proposed method (angular errors analysis by 3D graphics and numerical spherical statistics. Two packages in R programming language were performed to obtain graphics automatically. The results indicated that the proposed method is advantageous as it offers a more complete analysis of the positional accuracy, such as angular error component, uniformity of the vector distribution, error isotropy, and error, in addition the modular error component by linear statistics.

  11. Numerical Simulation for Three-Dimensional (3D) Unsteady State Temperature Field in Circumferential Laser Oxygen Cutting of Pipes

    Institute of Scientific and Technical Information of China (English)

    Kaijin HUANG; Dawen ZENG; Changsheng XIE; Desheng XU

    2003-01-01

    A 3D unsteady state numerical model of heat transfer in the circumferential laser oxygen cutting of pipes wasdeveloped. In order to minimize the computing time required for solving the finite difference equations as much aspossible, the alternating direct

  12. Documentation and Instructions for Running Two Python Scripts that Aid in Setting up 3D Measurements using the Polytec 3D Scanning Laser Doppler Vibrometer.

    Energy Technology Data Exchange (ETDEWEB)

    Rohe, Daniel Peter [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-24

    Sandia National Laboratories has recently purchased a Polytec 3D Scanning Laser Doppler Vibrometer for vibration measurement. This device has proven to be a very nice tool for making vibration measurements, and has a number of advantages over traditional sensors such as accelerometers. The non-contact nature of the laser vibrometer means there is no mass loading due to measuring the response. Additionally, the laser scanning heads can position the laser spot much more quickly and accurately than placing an accelerometer or performing a roving hammer impact. The disadvantage of the system is that a significant amount of time must be invested to align the lasers with each other and the part so that the laser spots can be accurately positioned. The Polytec software includes a number of nice tools to aid in this procedure; however, certain portions are still tedious. Luckily, the Polytec software is readily extensible by programming macros for the system, so tedious portions of the procedure can be made easier by automating the process. The Polytec Software includes a WinWrap (similar to Visual Basic) editor and interface to run macros written in that programming language. The author, however, is much more proficient in Python, and the latter also has a much larger set of libraries that can be used to create very complex macros, while taking advantage of Python’s inherent readability and maintainability.

  13. Ultra-Rapid 2-D and 3-D Laser Microprinting of Proteins

    Science.gov (United States)

    Scott, Mark Andrew

    When viewed under the microscope, biological tissues reveal an exquisite microarchitecture. These complex patterns arise during development, as cells interact with a multitude of chemical and mechanical cues in the surrounding extracellular matrix. Tissue engineers have sought for decades to repair or replace damaged tissue, often relying on porous scaffolds as an artificial extracellular matrix to support cell development. However, these grafts are unable to recapitulate the complexity of the in vivo environment, limiting our ability to regenerate functional tissue. Biomedical engineers have developed several methods for printing two- and three-dimensional patterns of proteins for studying and directing cell development. Of these methods, laser microprinting of proteins has shown the most promise for printing sub-cellular resolution gradients of cues, but the photochemistry remains too slow to enable large-scale applications for screening and therapeutics In this work, we demonstrate a novel high-speed photochemistry based on multi-photon photobleaching of fluorescein, and we build the fastest 2-D and 3-D laser microprinter for proteins to date. First, we show that multiphoton photobleaching of a deoxygenated solution of biotin-4-fluorescein onto a PEG monolayer with acrylate end-group can enable print speeds of almost 20 million pixels per second at 600 nanometer resolution. We discovered that the mechanism of fluorescein photobleaching evolves from a 2-photon to 3- and 4-photon regime at higher laser intensities, unlocking faster printing kinetics. Using this 2-D printing system, we develop a novel triangle-ratchet method for directing the polarization of single hippocampal neurons. This ability to determine which neurite becomes an axon, and which neuritis become dendrites is an essential step for developing defined in vitro neural networks. Next, we modify our multiphoton photobleaching system to print in three dimensions. For the first time, we demonstrate 3

  14. 3D BUILDING FAÇADE RECONSTRUCTION USING HANDHELD LASER SCANNING DATA

    Directory of Open Access Journals (Sweden)

    F. Sadeghi

    2015-12-01

    Full Text Available 3D The three dimensional building modelling has been an interesting topic of research for decades and it seems that photogrammetry methods provide the only economic means to acquire truly 3D city data. According to the enormous developments of 3D building reconstruction with several applications such as navigation system, location based services and urban planning, the need to consider the semantic features (such as windows and doors becomes more essential than ever, and therefore, a 3D model of buildings as block is not any more sufficient. To reconstruct the façade elements completely, we employed the high density point cloud data that obtained from the handheld laser scanner. The advantage of the handheld laser scanner with capability of direct acquisition of very dense 3D point clouds is that there is no need to derive three dimensional data from multi images using structure from motion techniques. This paper presents a grammar-based algorithm for façade reconstruction using handheld laser scanner data. The proposed method is a combination of bottom-up (data driven and top-down (model driven methods in which, at first the façade basic elements are extracted in a bottom-up way and then they are served as pre-knowledge for further processing to complete models especially in occluded and incomplete areas. The first step of data driven modelling is using the conditional RANSAC (RANdom SAmple Consensus algorithm to detect façade plane in point cloud data and remove noisy objects like trees, pedestrians, traffic signs and poles. Then, the façade planes are divided into three depth layers to detect protrusion, indentation and wall points using density histogram. Due to an inappropriate reflection of laser beams from glasses, the windows appear like holes in point cloud data and therefore, can be distinguished and extracted easily from point cloud comparing to the other façade elements. Next step, is rasterizing the indentation layer that

  15. Laser Scanning for 3D Object Characterization: Infrastructure for Exploration and Analysis of Vegetation Signatures

    Science.gov (United States)

    Koenig, K.; Höfle, B.

    2012-04-01

    Mapping and characterization of the three-dimensional nature of vegetation is increasingly gaining in importance. Deeper insight is required for e.g. forest management, biodiversity assessment, habitat analysis, precision agriculture, renewable energy production or the analysis of interaction between biosphere and atmosphere. However the potential of 3D vegetation characterization has not been exploited so far and new technologies are needed. Laser scanning has evolved into the state-of-the-art technology for highly accurate 3D data acquisition. By now several studies indicated a high value of 3D vegetation description by using laser data. The laser sensors provide a detailed geometric presentation (geometric information) of scanned objects as well as a full profile of laser energy that was scattered back to the sensor (radiometric information). In order to exploit the full potential of these datasets, profound knowledge on laser scanning technology for data acquisition, geoinformation technology for data analysis and object of interest (e.g. vegetation) for data interpretation have to be joined. A signature database is a collection of signatures of reference vegetation objects acquired under known conditions and sensor parameters and can be used to improve information extraction from unclassified vegetation datasets. Different vegetation elements (leaves, branches, etc.) at different heights above ground with different geometric composition contribute to the overall description (i.e. signature) of the scanned object. The developed tools allow analyzing tree objects according to single features (e.g. echo width and signal amplitude) and to any relation of features and derived statistical values (e.g. ratio of laser point attributes). For example, a single backscatter cross section value does not allow for tree species determination, whereas the average echo width per tree segment can give good estimates. Statistical values and/or distributions (e.g. Gaussian

  16. Freeform drop-on-demand laser printing of 3D alginate and cellular constructs.

    Science.gov (United States)

    Xiong, Ruitong; Zhang, Zhengyi; Chai, Wenxuan; Huang, Yong; Chrisey, Douglas B

    2015-12-22

    Laser printing is an orifice-free printing approach and has been investigated for the printing of two-dimensional patterns and simple three-dimensional (3D) constructs. To demonstrate the potential of laser printing as an effective bioprinting technique, both straight and Y-shaped tubes have been freeform printed using two different bioinks: 8% alginate solution and 2% alginate-based mouse fibroblast suspension. It has been demonstrated that 3D cellular tubes, including constructs with bifurcated overhang structures, can be adequately fabricated under optimal printing conditions. The post-printing cell viabilities immediately after printing as well as after 24 h incubation are above 60% for printed straight and Y-shaped fibroblast tubes. During fabrication, overhang and spanning structures can be printed using a dual-purpose crosslinking solution, which also functions as a support material. The advancement distance of gelation reaction front after a cycle time of the receiving platform downward motion should be estimated for experimental planning. The optimal downward movement step size of receiving platform should be chosen to be equal to the height of ungelled portion of a previously printed layer.

  17. Laser 3D micro/nanofabrication of polymers for tissue engineering applications

    Science.gov (United States)

    Danilevičius, P.; Rekštytė, S.; Balčiūnas, E.; Kraniauskas, A.; Širmenis, R.; Baltriukienė, D.; Bukelskienė, V.; Gadonas, R.; Sirvydis, V.; Piskarskas, A.; Malinauskas, M.

    2013-02-01

    In this work, we applied a constructed multi-photon polymerization system based on diode-pumped solid state femtosecond Yb:KGW laser used as pulsed irradiation light source (300 fs, 1030 nm, 200 kHz) in combination with large area high sample translation velocity (up to 300 mm/s) linear motor-driven stages (100×100×50 mm3) designed for high resolution and throughput 3D micro/nanofabrication. It enables rapid prototyping out of most polymers up to cm in scale with sub-micrometer spatial resolution. This can be used for production of three-dimensional artificial polymeric scaffolds applied for cell growth and expansion experiments as well as tissue engineering. Biocompatibilities of different acrylate, hybrid organic-inorganic and biodegradable polymeric materials were evaluated experimentally in vitro. Various in size and form scaffolds of biocompatible photopolymers were successfully fabricated having intricate 3D geometry, thus demonstrating the potential of the applied method. Adult rabbit myogenic stem cell proliferation tests show artificial scaffolds to be applicable for biomedical practice. Additionally, a micromolding technique was used for a rapid multiplication of adequate laser manufactured structures.

  18. The development of laser-plasma interaction program LAP3D on thousands of processors

    Directory of Open Access Journals (Sweden)

    Xiaoyan Hu

    2015-08-01

    Full Text Available Modeling laser-plasma interaction (LPI processes in real-size experiments scale is recognized as a challenging task. For explorering the influence of various instabilities in LPI processes, a three-dimensional laser and plasma code (LAP3D has been developed, which includes filamentation, stimulated Brillouin backscattering (SBS, stimulated Raman backscattering (SRS, non-local heat transport and plasmas flow computation modules. In this program, a second-order upwind scheme is applied to solve the plasma equations which are represented by an Euler fluid model. Operator splitting method is used for solving the equations of the light wave propagation, where the Fast Fourier translation (FFT is applied to compute the diffraction operator and the coordinate translations is used to solve the acoustic wave equation. The coupled terms of the different physics processes are computed by the second-order interpolations algorithm. In order to simulate the LPI processes in massively parallel computers well, several parallel techniques are used, such as the coupled parallel algorithm of FFT and fluid numerical computation, the load balance algorithm, and the data transfer algorithm. Now the phenomena of filamentation, SBS and SRS have been studied in low-density plasma successfully with LAP3D. Scalability of the program is demonstrated with a parallel efficiency above 50% on about ten thousand of processors.

  19. Electromagnetic induction sounding and 3D laser imaging in support of a Mars methane analogue mission

    Science.gov (United States)

    Boivin, A.; Lai, P.; Samson, C.; Cloutis, E.; Holladay, S.; Monteiro Santos, F. A.

    2013-07-01

    The Mars Methane Analogue Mission simulates a micro-rover mission whose purpose is to detect, analyze, and determine the source of methane emissions on the planet's surface. As part of this project, both an electromagnetic induction sounder (EMIS) and a high-resolution triangulation-based 3D laser scanner were tested at the Jeffrey open-pit asbestos mine to identify and characterize geological environments favourable to the occurrence of methane. The presence of serpentinite in the form of chrysotile (asbestos), magnesium carbonate, and iron oxyhydroxides make the mine a likely location for methane production. The EMIS clearly delineated the contacts between the two geological units found at the mine, peridotite and slate, which are separated by a shear zone. Both the peridotite and slate units have low and uniform apparent electrical conductivity and magnetic susceptibility, while the shear zone has much higher conductivity and susceptibility, with greater variability. The EMIS data were inverted and the resulting model captured lateral conductivity variations through the different bedrock geological units buried beneath a gravel road. The 3D point cloud data acquired by the laser scanner were fitted with triangular meshes where steeply dipping triangles were plotted in dark grey to accentuate discontinuities. The resulting images were further processed using Sobel edge detection to highlight networks of fractures which are potential pathways for methane seepage.

  20. Finding the displacement of wood structure in heritage building by 3D laser scanner

    Science.gov (United States)

    Lee, M. C.; Tsai, Y. L.; Wang, R. Z.; Lin, M. L.

    2015-08-01

    Heritage buildings are highly prone to long term damage from the microclimate, scourge and vandalism, which can result in damaged materials, structures, painting and cultural heritage items. This study will focus on finding the displacement of wood structural members through the use of a 3D laser scanner and the 4D concept of time. The results will compare the scans from different periods to find the difference (if any) in the structural member position. Wood structures usually consist of numerous wood members connected to form the structure. However, these members can be damaged in various ways such as physical mechanisms, chemical reactions, and biological corrosion. When damage to the wood structure occurs, the structural displacement can be affected, and if affected severely, can lead to a building collapse. Monitoring of the structural displacement is the best way to discover damage immediately and to preserve the heritage building. However, the Cultural Heritage Preservation Law in Taiwan prohibits the installation of monitoring instruments (e.g strain gauge, accelerometer) in historic structures (heritage buildings). Scanning the wood structure with 3D lasers is the most non-intrusive method and quickly achieves displacement through visualization. The displacement scan results can be compared with different periods and different members to analyze the severity of damage. Once the 3D scanner is installed, the whole building is scanned, and point clouds created to build the visual building model. The structural displacement can be checked via the building model and the differences are measured between each member to find the high risk damaged areas or members with large displacement. Early detection of structural damage is the most effective way means of preservation.

  1. IMPROVEMENT OF 3D MONTE CARLO LOCALIZATION USING A DEPTH CAMERA AND TERRESTRIAL LASER SCANNER

    Directory of Open Access Journals (Sweden)

    S. Kanai

    2015-05-01

    Full Text Available Effective and accurate localization method in three-dimensional indoor environments is a key requirement for indoor navigation and lifelong robotic assistance. So far, Monte Carlo Localization (MCL has given one of the promising solutions for the indoor localization methods. Previous work of MCL has been mostly limited to 2D motion estimation in a planar map, and a few 3D MCL approaches have been recently proposed. However, their localization accuracy and efficiency still remain at an unsatisfactory level (a few hundreds millimetre error at up to a few FPS or is not fully verified with the precise ground truth. Therefore, the purpose of this study is to improve an accuracy and efficiency of 6DOF motion estimation in 3D MCL for indoor localization. Firstly, a terrestrial laser scanner is used for creating a precise 3D mesh model as an environment map, and a professional-level depth camera is installed as an outer sensor. GPU scene simulation is also introduced to upgrade the speed of prediction phase in MCL. Moreover, for further improvement, GPGPU programming is implemented to realize further speed up of the likelihood estimation phase, and anisotropic particle propagation is introduced into MCL based on the observations from an inertia sensor. Improvements in the localization accuracy and efficiency are verified by the comparison with a previous MCL method. As a result, it was confirmed that GPGPU-based algorithm was effective in increasing the computational efficiency to 10-50 FPS when the number of particles remain below a few hundreds. On the other hand, inertia sensor-based algorithm reduced the localization error to a median of 47mm even with less number of particles. The results showed that our proposed 3D MCL method outperforms the previous one in accuracy and efficiency.

  2. ADVANCED 3D LASER MICROSCOPY FOR MEASUREMENTS AND ANALYSIS OF VITRIFIED BONDED ABRASIVE TOOLS

    Directory of Open Access Journals (Sweden)

    WOJCIECH KAPLONEK

    2012-12-01

    Full Text Available In many applications, when a precise non-contact assessment of an abrasive tools’ surface is required, alternative measurement methods are often used. Their use offers numerous advantages (referential method as they introduce new qualities into routinely realized measurements. Over the past few years there has been a dynamic increase in the interest for using new types of classical confocal microscopy. These new types are often defined as 3D laser microscopy. This paper presents select aspects of one such method’s application – confocal laser scanning microscopy – for diagnostic analysis of abrasive tools. In addition this paper also looks at the basis for operation, the origins and the development of this measurement technique.The experimental part of this paper presents the select results of tests carried out on grinding wheel active surfaces with sintered microcrystalline corundum grains SG™ bound with glass-crystalline bond. The 3D laser measuring microscopes LEXT OLS3100 and LEXT OLS4000 by Olympus were used in the experiments. Analysis of the obtained measurement data was carried out in dedicated OLS 5.0.9 and OLS4100 2.1 programs, supported by specialist TalyMap Platinum 5.0 software. The realized experiments confirmed the possibility of using the offered measurement method. This concerns both the assessment of grinding wheel active surfaces and their defects, as well as the internal structures of the tools (grain-bond connections. The method presented is an interesting alternative to the typical methods used in the diagnostics of abrasive tools.

  3. Tomographic imaging of reacting flows in 3D by laser absorption spectroscopy

    Science.gov (United States)

    Foo, J.; Martin, P. A.

    2017-05-01

    This paper describes the development of an infrared laser absorption tomography system for the 3D volumetric imaging of chemical species and temperature in reacting flows. The system is based on high-resolution near-infrared tunable diode laser absorption spectroscopy (TDLAS) for the measurement of water vapour above twin, mixed fuel gas burners arranged with an asymmetrical output. Four parallel laser beams pass through the sample region and are rotated rapidly in a plane to produce a wide range of projection angles. A rotation of 180° with 0.5° sampling was achieved in 3.6 s. The effects of changes to the burner fuel flow were monitored in real time for the 2D distributions. The monitoring plane was then moved vertically relative to the burners enabling a stack of 2D images to be produced which were then interpolated to form a 3D volumetric image of the temperature and water concentrations above the burners. The optical transmission of each beam was rapidly scanned around 1392 nm and the spectrum was fitted to find the integrated absorbance of the water transitions and although several are probed in each scan, two of these transitions possess opposite temperature dependencies. The projections of the integrated absorbances at each angle form the sinogram from which the 2D image of integrated absorbance of each line can be reconstructed by the direct Fourier reconstruction based on the Fourier slice theorem. The ratio of the integrated absorbances of the two lines can then be related to temperature alone in a method termed, two-line thermometry. The 2D temperature distribution obtained was validated for pattern and accuracy by thermocouple measurements. With the reconstructed temperature distribution, the temperature-dependent line strengths could be determined and subsequently the concentration distribution of water across the 2D plane whilst variations in burner condition were carried out. These results show that the measurement system based on TDLAS can be

  4. Laser Fabrication of Affective 3D Objects with 1/f Fluctuation

    Science.gov (United States)

    Maekawa, Katsuhiro; Nishii, Tomohiro; Hayashi, Terutake; Akabane, Hideo; Agu, Masahiro

    The present paper describes the application of Kansei Engineering to the physical design of engineering products as well as its realization by laser sintering. We have investigated the affective information that might be included in three-dimensional objects such as a ceramic bowl for the tea ceremony. First, an X-ray CT apparatus is utilized to retrieve surface data from the teabowl, and then a frequency analysis is carried out after noise has been filtered. The surface fluctuation is characterized by a power spectrum that is in inverse proportion to the wave number f in circumference. Second, we consider how to realize the surface with a 1/f fluctuation on a computer screen using a 3D CAD model. The fluctuation is applied to a reference shape assuming that the outer surface has a spiral flow line on which unevenness is superimposed. Finally, the selective laser sintering method has been applied to the fabrication of 1/f fluctuation objects. Nylon powder is sintered layer by layer using a CO2 laser to form an artificial teabowl with complicated surface contours.

  5. 3D MHD Simulations of Laser Plasma Guiding in Curved Magnetic Field

    Science.gov (United States)

    Roupassov, S.; Rankin, R.; Tsui, Y.; Capjack, C.; Fedosejevs, R.

    1999-11-01

    The guiding and confinement of laser produced plasma in a curved magnetic field has been investigated numerically. These studies were motivated by experiments on pulsed laser deposition of diamond-like films [1] in which a 1kG magnetic field in a curved solenoid geometry was utilized to steer a carbon plasma around a curved trajectory and thus to separate it from unwanted macroparticles produced by the laser ablation. The purpose of the modeling was to characterize the plasma dynamics during the propagation through the magnetic guide field and to investigate the effect of different magnetic field configurations. A 3D curvilinear ADI code developed on the basis of an existing Cartesian code [2] was employed to simulate the underlying resistive one-fluid MHD model. Issues such as large regions of low background density and nonreflective boundary conditions were addressed. Results of the simulations in a curved guide field will be presented and compared to experimental results. [1] Y.Y. Tsui, D. Vick and R. Fedosejevs, Appl. Phys. Lett. 70 (15), pp. 1953-57, 1997. [2] R. Rankin, and I. Voronkov, in "High Performance Computing Systems and Applications", pp. 59-69, Kluwer AP, 1998.

  6. Performance evaluation of laser line scanner for in-process inspection of 3D geometries

    Science.gov (United States)

    Zhou, Sen; Xu, Jian; Tao, Lei; Yan, Yu

    2016-09-01

    Non-contact measurement techniques using laser scanning have the power to deliver tremendous benefits to most notably manufacturing, and have the advantage of high speed and high detail output. However, a major obstacle to their widespread adoption in more complex on-line producing environments is their geometric constraints and low accuracy compared to the contact-based counterparts. The work presented in this paper introduces a performance evaluation test of laser line scanning for in-process inspection of 3D geometries. Some straightforward test methods that use a designed artifact are proposed. First, one work aims to experimentally investigate the location accuracy of knee point or corner point of edge features using a commercial laser stripe scanner, which is common in mechanical parts. Another work experimentally investigates the formation of outliers that may be usually promoted by reflective surfaces around surrounding area of corner point, and these outliers are characterized with large measurement errors, which significantly deteriorate the quality of the scanned point cloud data. Scanning path planning and outlier filter design are respectively discussed.

  7. 3D DATA ACQUISITION FOR INDOOR ASSETS USING TERRESTRIAL LASER SCANNING

    OpenAIRE

    Lee, S. Y.; Z Majid; H. Setan

    2013-01-01

    The newly development of technology clearly shows an improvement of three-dimension (3D) data acquisition techniques. The requirements of 3D information and features have been obviously increased during past few years in many related fields. Generally, 3D visualization can provide more understanding and better analysis for making decision. The need of 3D GIS also pushed by the highly demand of 3D in geospatial related applications as well as the existing fast and accurate 3D data col...

  8. Recent advances in two-photon 3D laser lithography with self-Q-switched Nd:YAG microchip lasers

    Science.gov (United States)

    Baldeck, Patrice L.; Prabhakaran, Prem; Liu, Chao-Yuan; Bouriau, Michel; Gredy, Laetitia; Stephan, Olivier; Vergote, Thomas; Chaumeil, Hélène; Malval, Jean-Pierre; Lee, Yi-Hsiung; Lin, Chih-Lang; Lin, Chin-Te; Hsueh, Ya Hsun; Chung, Tien-Tung

    2013-09-01

    We review our recent results towards the development of a turnkey 3D laser printer, based on self-Q-switched microchip Nd:YAG lasers, with reproducible sub-100nm resolution, and with large-scale (cm) and fast-speed (cm/sec) capability at micron resolution. First of all, we report on line fabrication with 70nm lateral, and 150nm longitudinal resolutions without significant shrinking. This is due to the tight focusing with green visible wavelength, large numerical aperture, and excellent resin properties. Secondly, we report on two-photon sensitive photoacid generators that lead to efficient 3D microfabrication with epoxy SU-8 resin. Thirdly, we demonstrate high-speed microfabrication of large scale, millimeter size, scaffolds and cemtimeter height needle with high repetition rate (130Khz), and high average power (1W) amplified microchip laser. Finally we demonstrate the two-photon induced cross-linking of antibodies to determine the type of red blood cells in microfluidic channels.

  9. Solid state synthesis of chitosan and its unsaturated derivatives for laser microfabrication of 3D scaffolds

    Science.gov (United States)

    Akopova, T. A.; Demina, T. S.; Bagratashvili, V. N.; Bardakova, K. N.; Novikov, M. M.; Selezneva, I. I.; Istomin, A. V.; Svidchenko, E. A.; Cherkaev, G. V.; Surin, N. M.; Timashev, P. S.

    2015-07-01

    Chitosans with various degrees of deacetylation and molecular weights and their allyl substituted derivatives were obtained through a solvent-free reaction under shear deformation in an extruder. Structure and physical-chemical analysis of the samples were carried out using nuclear magnetic resonance (NMR), ultraviolet (UV) and infrared radiation (IR) spectroscopy. Photosensitive materials based on the synthesized polymers were successfully used for microfabrication of 3D well-defined architectonic structures by laser stereolithography. Study on the metabolic activity of NCTC L929 cultured in the presence of the cured chitosan extracts indicates that the engineered biomaterials could support adhesion, spreading and growth of adherent-dependent cells, and thus could be considered as biocompatible scaffolds.

  10. Fast Compact Laser Shutter Using a Direct Current Motor and 3D Printing

    CERN Document Server

    Zhang, Grace H; Kawasaki, Akio; Vuletić, Vladan

    2015-01-01

    We present a mechanical laser shutter design that utilizes a DC electric motor to rotate a blade which blocks and unblocks a light beam. The blade and the main body of the shutter are modeled with computer aided design (CAD) and are produced by 3D printing. Rubber flaps are used to limit the blade's range of motion, reducing vibrations and preventing undesirable blade oscillations. At its nominal operating voltage, the shutter achieves a switching speed of (1.22 $\\pm$ 0.02) m/s with 1 ms activation delay and 10 $\\mu$s jitter in its timing performance. The shutter design is simple, easy to replicate, and highly reliable, showing no failure or degradation in performance over more than $10^8$ cycles.

  11. A high sensitive 66 dB linear dynamic range receiver for 3-D laser radar

    Science.gov (United States)

    Ma, Rui; Zheng, Hao; Zhu, Zhangming

    2017-08-01

    This study presents a CMOS receiver chip realized in 0.18 μm standard CMOS technology and intended for high precision 3-D laser radar. The chip includes an adjustable gain transimpedance pre-amplifier, a post-amplifier and two timing comparators. An additional feedback is employed in the regulated cascode transimpedance amplifier to decrease the input impedance, and a variable gain transimpedance amplifier controlled by digital switches and analog multiplexer is utilized to realize four gain modes, extending the input dynamic range. The measurement shows that the highest transimpedance of the channel is 50 k {{Ω }}, the uncompensated walk error is 1.44 ns in a wide linear dynamic range of 66 dB (1:2000), and the input referred noise current is 2.3 pA/\\sqrt{{Hz}} (rms), resulting in a very low detectable input current of 1 μA with SNR = 5.

  12. 3D local feature BKD to extract road information from mobile laser scanning point clouds

    Science.gov (United States)

    Yang, Bisheng; Liu, Yuan; Dong, Zhen; Liang, Fuxun; Li, Bijun; Peng, Xiangyang

    2017-08-01

    Extracting road information from point clouds obtained through mobile laser scanning (MLS) is essential for autonomous vehicle navigation, and has hence garnered a growing amount of research interest in recent years. However, the performance of such systems is seriously affected due to varying point density and noise. This paper proposes a novel three-dimensional (3D) local feature called the binary kernel descriptor (BKD) to extract road information from MLS point clouds. The BKD consists of Gaussian kernel density estimation and binarization components to encode the shape and intensity information of the 3D point clouds that are fed to a random forest classifier to extract curbs and markings on the road. These are then used to derive road information, such as the number of lanes, the lane width, and intersections. In experiments, the precision and recall of the proposed feature for the detection of curbs and road markings on an urban dataset and a highway dataset were as high as 90%, thus showing that the BKD is accurate and robust against varying point density and noise.

  13. Laser irradiated fluorescent perfluorocarbon microparticles in 2-D and 3-D breast cancer cell models

    Science.gov (United States)

    Niu, Chengcheng; Wang, Long; Wang, Zhigang; Xu, Yan; Hu, Yihe; Peng, Qinghai

    2017-01-01

    Perfluorocarbon (PFC) droplets were studied as new generation ultrasound contrast agents via acoustic or optical droplet vaporization (ADV or ODV). Little is known about the ODV irradiated vaporization mechanisms of PFC-microparticle complexs and the stability of the new bubbles produced. In this study, fluorescent perfluorohexane (PFH) poly(lactic-co-glycolic acid) (PLGA) particles were used as a model to study the process of particle vaporization and bubble stability following excitation in two-dimensional (2-D) and three-dimensional (3-D) cell models. We observed localization of the fluorescent agent on the microparticle coating material initially and after vaporization under fluorescence microscopy. Furthermore, the stability and growth dynamics of the newly created bubbles were observed for 11 min following vaporization. The particles were co-cultured with 2-D cells to form 3-D spheroids and could be vaporized even when encapsulated within the spheroids via laser irradiation, which provides an effective basis for further work. PMID:28262671

  14. Railway Tunnel Clearance Inspection Method Based on 3D Point Cloud from Mobile Laser Scanning.

    Science.gov (United States)

    Zhou, Yuhui; Wang, Shaohua; Mei, Xi; Yin, Wangling; Lin, Chunfeng; Hu, Qingwu; Mao, Qingzhou

    2017-09-07

    Railway tunnel clearance is directly related to the safe operation of trains and upgrading of freight capacity. As more and more railway are put into operation and the operation is continuously becoming faster, the railway tunnel clearance inspection should be more precise and efficient. In view of the problems existing in traditional tunnel clearance inspection methods, such as low density, slow speed and a lot of manual operations, this paper proposes a tunnel clearance inspection approach based on 3D point clouds obtained by a mobile laser scanning system (MLS). First, a dynamic coordinate system for railway tunnel clearance inspection has been proposed. A rail line extraction algorithm based on 3D linear fitting is implemented from the segmented point cloud to establish a dynamic clearance coordinate system. Second, a method to seamlessly connect all rail segments based on the railway clearance restrictions, and a seamless rail alignment is formed sequentially from the middle tunnel section to both ends. Finally, based on the rail alignment and the track clearance coordinate system, different types of clearance frames are introduced for intrusion operation with the tunnel section to realize the tunnel clearance inspection. By taking the Shuanghekou Tunnel of the Chengdu-Kunming Railway as an example, when the clearance inspection is carried out by the method mentioned herein, its precision can reach 0.03 m, and difference types of clearances can be effectively calculated. This method has a wide application prospects.

  15. High-resolution laser radar for 3D imaging in artwork cataloging, reproduction, and restoration

    Science.gov (United States)

    Ricci, Roberto; Fantoni, Roberta; Ferri de Collibus, Mario; Fornetti, Giorgio G.; Guarneri, Massimiliano; Poggi, Claudio

    2003-10-01

    A high resolution Amplitude Modulated Laser Radar (AM-LR) sensor has recently been developed, aimed at accurately reconstructing 3D digital models of real targets, either single objects or complex scenes. The sensor sounding beam can be swept linearly across the object or circularly around it, by placing the object on a controlled rotating platform, enabling to obtain respectively linear and cylindrical range maps. Both amplitude and phase shift of the modulating wave of back-scattered light are collected and processed, providing respectively a shade-free, high resolution, photographic-like picture and accurate range data in the form of a range image. The resolution of range measurements depends mainly on the laser modulation frequency, provided that the power of the backscattered light reaching the detector is at least a few nW (current best performances are ~100 μm). The complete object surface can be reconstructed from the sampled points by using specifically developed software tools. The system has been successfully applied to scan different types of real surfaces (stone, wood, alloys, bones), with relevant applications in different fields, ranging from industrial machining to medical diagnostics, to vision in hostile environments. Examples of artwork reconstructed models (pottery, marble statues) are presented and the relevance of this technology for reverse engineering applied to cultural heritage conservation and restoration are discussed. Final 3D models can be passed to numeric control machines for rapid-prototyping, exported in standard formats for CAD/CAM purposes and made available on the Internet by adopting a virtual museum paradigm, thus possibly enabling specialists to perform remote inspections on high resolution digital reproductions of hardly accessible masterpieces.

  16. Thin film passivation of laser generated 3D micro patterns in lithium manganese oxide cathodes

    Science.gov (United States)

    Pröll, J.; Kohler, R.; Bruns, M.; Oberst, V.; Weidler, P. G.; Heißler, S.; Kübel, C.; Scherer, T.; Prang, R.; Seifert, H. J.; Pfleging, W.

    2013-03-01

    The increasing need for long-life lithium-ion batteries requires the further development of electrode materials. Especially on the cathode side new materials or material composites are needed to increase the cycle lifetime. On the one hand, spinel-type lithium manganese oxide is a promising candidate to be used as cathode material due to its non-toxicity, low cost and good thermal stability. On the other hand, the spinel structure suffers from change in the oxidation state of manganese during cycling which is also accompanied by loss of active material into the liquid electrolyte. The general trend is to enhance the active surface area of the cathode in order to increase lithium-ion mobility through the electrode/electrolyte interface, while an enhanced surface area will also promote chemical degradation. In this work, laser microstructuring of lithium manganese oxide thin films was applied in a first step to increase the active surface area. This was done by using 248 nm excimer laser radiation and chromium/quartz mask imaging techniques. In a second step, high power diode laser-annealing operating at a wavelength of 940 nm was used for forming a cubic spinel-like battery phase. This was verified by means of Raman spectroscopy and cyclic voltammetric measurements. In a last step, the laser patterned thin films were coated with indium tin oxide (ITO) layers with a thickness of 10 nm to 50 nm. The influence of the 3D surface topography as well as the ITO thickness on the electrochemical performance was studied by cyclic voltammetry. Post-mortem studies were carried out by using scanning electron microscopy and focused ion beam analysis.

  17. Comparison between 3D model of Pisciarelli area (Campi Flegrei caldera) through Terrestrial Laser Scanner

    Science.gov (United States)

    Caputo, Teresa; Somma, Renato; Marino, Ermanno; Terracciano, Rosario; Troise, Claudia; De Natale, Giuseppe

    2016-04-01

    The volcanic/geothermal area of Pisciarelli is located within Campi Flegrei caldera .This last is a densely populated area, including the Pozzuoli town and bordering the western side of the Naples city, this causes a high vulnerability and consequently a high volcanic risk. In the recent decades this area has experienced minor ground uplift episodes accompanied by low magnitude seismicity and by strong intensification of degassing activity in particular localized at Pisciarelli area. We present the results of the Terrestrial Laser Scanner (TLS), using a Reigl VZ1000®, analysis of Pisciarelli area performed in June 2013 and the comparison with the data acquired later in March 2014. We apply the TLS technique based on Time of Flight (TOF) method in order to define an accurate 3D digital model for detailed analysis of this area performing numerous scans from different points of view in the area. In this ways was ensured a good coverage of the whole investigated area in order to avoid shaded portion due to the high soil degassing activity. Such fact limits the capacity of laser penetration is caused by wavelength near infrared range. For each survey was obtained a Digital Terrain Model (DTM) from the reconstructed data and both were compared. In particular, we have identified two "critical" areas of interest that will be monitored more frequently. These are: 1) in the lower part of the studied area a major fault line that bounding the Agnano caldera moderately NE-dipping; 2) in the upper part of the study area a zone of depletion with its zone of accumulation. The DTM were georeferenced into the UTM-WGS84 reference frame. The aim of this work is to define a procedure to compare between 3D model applied to monitoring of this area. Also to evaluate of volumetric and morphologic changes and to recognizing unstable masses by comparison of 3D data. For this purpose other TLS surveys will be performed in the upcoming in this active volcanic/geothermal area.

  18. Laser Scanning Holographic Lithography for Flexible 3D Fabrication of Multi-Scale Integrated Nano-structures and Optical Biosensors.

    Science.gov (United States)

    Yuan, Liang Leon; Herman, Peter R

    2016-01-01

    Three-dimensional (3D) periodic nanostructures underpin a promising research direction on the frontiers of nanoscience and technology to generate advanced materials for exploiting novel photonic crystal (PC) and nanofluidic functionalities. However, formation of uniform and defect-free 3D periodic structures over large areas that can further integrate into multifunctional devices has remained a major challenge. Here, we introduce a laser scanning holographic method for 3D exposure in thick photoresist that combines the unique advantages of large area 3D holographic interference lithography (HIL) with the flexible patterning of laser direct writing to form both micro- and nano-structures in a single exposure step. Phase mask interference patterns accumulated over multiple overlapping scans are shown to stitch seamlessly and form uniform 3D nanostructure with beam size scaled to small 200 μm diameter. In this way, laser scanning is presented as a facile means to embed 3D PC structure within microfluidic channels for integration into an optofluidic lab-on-chip, demonstrating a new laser HIL writing approach for creating multi-scale integrated microsystems.

  19. Optical 3D laser measurement system for navigation of autonomous mobile robot

    Science.gov (United States)

    Básaca-Preciado, Luis C.; Sergiyenko, Oleg Yu.; Rodríguez-Quinonez, Julio C.; García, Xochitl; Tyrsa, Vera V.; Rivas-Lopez, Moises; Hernandez-Balbuena, Daniel; Mercorelli, Paolo; Podrygalo, Mikhail; Gurko, Alexander; Tabakova, Irina; Starostenko, Oleg

    2014-03-01

    In our current research, we are developing a practical autonomous mobile robot navigation system which is capable of performing obstacle avoiding task on an unknown environment. Therefore, in this paper, we propose a robot navigation system which works using a high accuracy localization scheme by dynamic triangulation. Our two main ideas are (1) integration of two principal systems, 3D laser scanning technical vision system (TVS) and mobile robot (MR) navigation system. (2) Novel MR navigation scheme, which allows benefiting from all advantages of precise triangulation localization of the obstacles, mostly over known camera oriented vision systems. For practical use, mobile robots are required to continue their tasks with safety and high accuracy on temporary occlusion condition. Presented in this work, prototype II of TVS is significantly improved over prototype I of our previous publications in the aspects of laser rays alignment, parasitic torque decrease and friction reduction of moving parts. The kinematic model of the MR used in this work is designed considering the optimal data acquisition from the TVS with the main goal of obtaining in real time, the necessary values for the kinematic model of the MR immediately during the calculation of obstacles based on the TVS data.

  20. EEG-MRI co-registration and sensor labeling using a 3D laser scanner.

    Science.gov (United States)

    Koessler, L; Cecchin, T; Caspary, O; Benhadid, A; Vespignani, H; Maillard, L

    2011-03-01

    This paper deals with the co-registration of an MRI scan with EEG sensors. We set out to evaluate the effectiveness of a 3D handheld laser scanner, a device that is not widely used for co-registration, applying a semi-automatic procedure that also labels EEG sensors. The scanner acquired the sensors' positions and the face shape, and the scalp mesh was obtained from the MRI scan. A pre-alignment step, using the position of three fiducial landmarks, provided an initial value for co-registration, and the sensors were automatically labeled. Co-registration was then performed using an iterative closest point algorithm applied to the face shape. The procedure was conducted on five subjects with two scans of EEG sensors and one MRI scan each. The mean time for the digitization of the 64 sensors and three landmarks was 53 s. The average scanning time for the face shape was 2 min 6 s for an average number of 5,263 points. The mean residual error of the sensors co-registration was 2.11 mm. These results suggest that the laser scanner associated with an efficient co-registration and sensor labeling algorithm is sufficiently accurate, fast and user-friendly for longitudinal and retrospective brain sources imaging studies.

  1. Robust polarization filter for separation of Lamb wave modes acquired using a 3D laser vibrometer

    Science.gov (United States)

    Ambroziński, Łukasz; Stepinski, Tadeusz

    2017-09-01

    Interpretation of signals related to Lamb waves propagation and scattering can rise serious difficulties due to the multi-modal nature of these waves. Different modes propagating with different velocities can be mixed up and hinder extraction of damage reflected components. As a feasible solution to this problem we propose a technique for separation of the propagating modes using a new type of polarization filter. The proposed directional polarization filter (DPF) can be applied if two components of particle movement, the in-plane and the out-of-plane, are available, for instance, from the measurement performed using laser vibrometer. The DPF is robust in the sense that it does not need a complete amplitude information of both components. Operation principle of the DPF is presented and illustrated by the simulated results in the form of B-scans obtained for an aluminum plate. The simulated results are verified by the experimental data obtained by processing the signals captured using a 3D laser vibrometer.

  2. Direct laser writing of 3D scaffolds for neural tissue engineering applications

    Energy Technology Data Exchange (ETDEWEB)

    Melissinaki, V; Vamvakaki, M; Ranella, A; Fotakis, C; Farsari, M [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion, Crete (Greece); Gill, A A; Ortega, I; Haycock, J W; Claeyssens, F, E-mail: M.Farsari@iesl.forth.gr, E-mail: F.Claeyssens@sheffield.ac.uk [Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Broad Lane, Sheffield, S3 7HQ (United Kingdom)

    2011-12-15

    This study reports on the production of high-resolution 3D structures of polylactide-based materials via multi-photon polymerization and explores their use as neural tissue engineering scaffolds. To achieve this, a liquid polylactide resin was synthesized in house and rendered photocurable via attaching methacrylate groups to the hydroxyl end groups of the small molecular weight prepolymer. This resin cures easily under UV irradiation, using a mercury lamp, and under femtosecond IR irradiation. The results showed that the photocurable polylactide (PLA) resin can be readily structured via direct laser write (DLW) with a femtosecond Ti:sapphire laser and submicrometer structures can be produced. The maximum resolution achieved is 800 nm. Neuroblastoma cells were grown on thin films of the cured PLA material, and cell viability and proliferation assays revealed good biocompatibility of the material. Additionally, PC12 and NG108-15 neuroblastoma growth on bespoke scaffolds was studied in more detail to assess potential applications for neuronal implants of this material.

  3. Technology of Vehicle 3D Laser Scanning System Integration%车载3D 激光扫描系统集成技术

    Institute of Scientific and Technical Information of China (English)

    王力; 李广云; 李森; 杨凡; 李明磊

    2014-01-01

    移动激光扫描技术是从上世纪90年代初逐步发展起来的一门测绘技术,也是当今测绘界最为前沿的技术之一,可用于工程测量和制图等诸多领域。地面3D激光扫描仪具有测量速度快,精度高等优点。本文以奥地利RIEGL公司的地面三维激光扫描仪VZ400为例,研究将其作为移动测量系统的主要传感器所涉及的关键技术,包括联机控制、时间基准统一和空间基准统一三个方面:解析了激光扫描仪的接口定义,并结合联机控制的开发库---RiVLIB实现的仪器的联机控与数据通信;给出了基于GPS秒脉冲信号的时间同步原理,实现了系统时间基准的传递与统一;分析了移动测量系统中的坐标系,并根据地面三维激光扫描仪的实际情况,构建了单站的参数标定模型。通过本文的研究与实验,使测量系统实现常见移动测量的二维帧扫描模式以及针对重点区域的三维全景扫描模式,同时,当它闲置时还可将激光扫描仪拆卸进行静态的扫描,丰富了系统的测量方式,提高了系统的适应性与使用效率。%Mobile laser scanning technology was gradually developed as a surveying and mapping technology from the early 1990s ,and its also one of the most cutting-edge technologies in the today's field of surveying and mapping ,which can be applied for engineering surveying and mapping ,and many other fields .Terrestrial 3D laser scanner has advantages of high speed of measurement ,high precision and etc .This paper takes Austria 's Company RIEGL's terrestrial 3D laser scanner VZ400 as example ,and study the key technology it involves as the primary sensor of mobile measurement system ,including three aspects of online control ,unity of time reference and unity of spatial reference :parsing the interface definition of laser scanner ,and achieving online control and data communications of instruments with the online

  4. Comparison of simulated and experimental 3D laser images using a GmAPD array: application to long range detection

    Science.gov (United States)

    Coyac, Antoine; Riviere, Nicolas; Hespel, Laurent; Briottet, Xavier

    2016-05-01

    In this paper, we show the feasibility and the benefit to use a Geiger-mode Avalanche Photo-Diode (GmAPD) array for long range detection, up to several kilometers. A simulation of a Geiger detection sensor is described, which is a part of our end-to-end laser simulator, to generate simulated 3D laser images from synthetic scenes. Resulting 3D point clouds have been compared to experimental acquisitions, performed with our GmAPD 3D camera on similar scenarios. An operational case of long range detection is presented: a copper cable outstretched above the ground, 1 kilometer away the experimental system and with a horizontal line-of-sight (LOS). The detection of such a small object from long distance observation strongly suggests that GmAPD focal plane arrays could be easily used for real-time 3D mapping or surveillance applications from airborne platforms, with good spatial and temporal resolutions.

  5. Comparative Analysis of 3d Point Clouds Generated from a Freeware and Terrestrial Laser Scanner

    Science.gov (United States)

    Dayal, K. R.; Raghavendra, S.; Pande, H.; Tiwari, P. S.; Chauhan, I.

    2017-07-01

    In the recent past, several heritage structures have faced destruction due to both human-made incidents and natural calamities that have caused a great loss to the human race regarding its cultural achievements. In this context, the importance of documenting such structures to create a substantial database cannot be emphasised enough. The Clock Tower of Dehradun, India is one such structure. There is a lack of sufficient information in the digital domain, which justified the need to carry out this study. Thus, an attempt has been made to gauge the possibilities of using open source 3D tools such as VSfM to quickly and easily obtain point clouds of an object and assess its quality. The photographs were collected using consumer grade cameras with reasonable effort to ensure overlap. The sparse reconstruction and dense reconstruction were carried out to generate a 3D point cloud model of the tower. A terrestrial laser scanner (TLS) was also used to obtain a point cloud of the tower. The point clouds obtained from the two methods were analyzed to understand the quality of the information present; TLS acquired point cloud being a benchmark to assess the VSfM point cloud. They were compared to analyze the point density and subjected to a plane-fitting test for sample flat portions on the structure. The plane-fitting test revealed the planarity of the point clouds. A Gauss distribution fit yielded a standard deviation of 0.002 and 0.01 for TLS and VSfM, respectively. For more insight, comparisons with Agisoft Photoscan results were also made.

  6. Feature Based Modeling and Mapping of Tree Trunks and Natural Terrain Using 3D Laser Scanner Measurement System

    OpenAIRE

    Hyyti, Heikki; Visala, Arto

    2013-01-01

    This paper presents a novel approach to measure tree trunks and to model the ground using a 3D laser scanner. The 3D scanner, self-build using two 2D Sick scanners on a rotating base, measures each scan line approximately at 45° angle towards the ground and the trees. Single scan lines are segmented to find ground and tree returns. 3D point clouds from the surrounding forest are recorded while the measuring vehicle is moving. Sequential scan lines are joined together as the pose changes are r...

  7. 3D-Laser-Scanning Technique Applied to Bulk Density Measurements of Apollo Lunar Samples

    Science.gov (United States)

    Macke, R. J.; Kent, J. J.; Kiefer, W. S.; Britt, D. T.

    2015-01-01

    In order to better interpret gravimetric data from orbiters such as GRAIL and LRO to understand the subsurface composition and structure of the lunar crust, it is import to have a reliable database of the density and porosity of lunar materials. To this end, we have been surveying these physical properties in both lunar meteorites and Apollo lunar samples. To measure porosity, both grain density and bulk density are required. For bulk density, our group has historically utilized sub-mm bead immersion techniques extensively, though several factors have made this technique problematic for our work with Apollo samples. Samples allocated for measurement are often smaller than optimal for the technique, leading to large error bars. Also, for some samples we were required to use pure alumina beads instead of our usual glass beads. The alumina beads were subject to undesirable static effects, producing unreliable results. Other investigators have tested the use of 3d laser scanners on meteorites for measuring bulk volumes. Early work, though promising, was plagued with difficulties including poor response on dark or reflective surfaces, difficulty reproducing sharp edges, and large processing time for producing shape models. Due to progress in technology, however, laser scanners have improved considerably in recent years. We tested this technique on 27 lunar samples in the Apollo collection using a scanner at NASA Johnson Space Center. We found it to be reliable and more precise than beads, with the added benefit that it involves no direct contact with the sample, enabling the study of particularly friable samples for which bead immersion is not possible

  8. Comparison of 3D representations depicting micro folds: overlapping imagery vs. time-of-flight laser scanner

    Science.gov (United States)

    Vaiopoulos, Aristidis D.; Georgopoulos, Andreas; Lozios, Stylianos G.

    2012-10-01

    A relatively new field of interest, which continuously gains grounds nowadays, is digital 3D modeling. However, the methodologies, the accuracy and the time and effort required to produce a high quality 3D model have been changing drastically the last few years. Whereas in the early days of digital 3D modeling, 3D models were only accessible to computer experts in animation, working many hours in expensive sophisticated software, today 3D modeling has become reasonably fast and convenient. On top of that, with online 3D modeling software, such as 123D Catch, nearly everyone can produce 3D models with minimum effort and at no cost. The only requirement is panoramic overlapping images, of the (still) objects the user wishes to model. This approach however, has limitations in the accuracy of the model. An objective of the study is to examine these limitations by assessing the accuracy of this 3D modeling methodology, with a Terrestrial Laser Scanner (TLS). Therefore, the scope of this study is to present and compare 3D models, produced with two different methods: 1) Traditional TLS method with the instrument ScanStation 2 by Leica and 2) Panoramic overlapping images obtained with DSLR camera and processed with 123D Catch free software. The main objective of the study is to evaluate advantages and disadvantages of the two 3D model producing methodologies. The area represented with the 3D models, features multi-scale folding in a cipollino marble formation. The most interesting part and most challenging to capture accurately, is an outcrop which includes vertically orientated micro folds. These micro folds have dimensions of a few centimeters while a relatively strong relief is evident between them (perhaps due to different material composition). The area of interest is located in Mt. Hymittos, Greece.

  9. Optimization of 3D laser scanning speed by use of combined variable step

    Science.gov (United States)

    Garcia-Cruz, X. M.; Sergiyenko, O. Yu.; Tyrsa, Vera; Rivas-Lopez, M.; Hernandez-Balbuena, D.; Rodriguez-Quiñonez, J. C.; Basaca-Preciado, L. C.; Mercorelli, P.

    2014-03-01

    The problem of 3D TVS slow functioning caused by constant small scanning step becomes its solution in the presented research. It can be achieved by combined scanning step application for the fast search of n obstacles in unknown surroundings. Such a problem is of keynote importance in automatic robot navigation. To maintain a reasonable speed robots must detect dangerous obstacles as soon as possible, but all known scanners able to measure distances with sufficient accuracy are unable to do it in real time. So, the related technical task of the scanning with variable speed and precise digital mapping only for selected spatial sectors is under consideration. A wide range of simulations in MATLAB 7.12.0 of several variants of hypothetic scenes with variable n obstacles in each scene (including variation of shapes and sizes) and scanning with incremented angle value (0.6° up to 15°) is provided. The aim of such simulation was to detect which angular values of interval still permit getting the maximal information about obstacles without undesired time losses. Three of such local maximums were obtained in simulations and then rectified by application of neuronal network formalism (Levenberg-Marquradt Algorithm). The obtained results in its turn were applied to MET (Micro-Electro-mechanical Transmission) design for practical realization of variable combined step scanning on an experimental prototype of our previously known laser scanner.

  10. Automated Analysis of Barley Organs Using 3D Laser Scanning: An Approach for High Throughput Phenotyping

    Directory of Open Access Journals (Sweden)

    Stefan Paulus

    2014-07-01

    Full Text Available Due to the rise of laser scanning the 3D geometry of plant architecture is easy to acquire. Nevertheless, an automated interpretation and, finally, the segmentation into functional groups are still difficult to achieve. Two barley plants were scanned in a time course, and the organs were separated by applying a histogram-based classification algorithm. The leaf organs were represented by meshing algorithms, while the stem organs were parameterized by a least-squares cylinder approximation. We introduced surface feature histograms with an accuracy of 96% for the separation of the barley organs, leaf and stem. This enables growth monitoring in a time course for barley plants. Its reliability was demonstrated by a comparison with manually fitted parameters with a correlation R2 = 0:99 for the leaf area and R2 = 0:98 for the cumulated stem height. A proof of concept has been given for its applicability for the detection of water stress in barley, where the extension growth of an irrigated and a non-irrigated plant has been monitored.

  11. Separation of Lamb waves modes using polarization filter of 3D laser measured signals

    Science.gov (United States)

    Ambrozinski, Lukasz; Stepinski, Tadeusz; Uhl, Tadeusz

    2015-04-01

    Interpretation of Lamb waves signals can rise serious difficulties due to their multi-modal nature. Different modes propagating with different velocities can be misleading with damage reflected components. As a solution to this problem we propose a technique capable of modes separation based on a polarization filter. Both S0 and A0 Lamb modes exhibit elliptical polarization, however, their polarization parameters, i.e. the ratios of in-plane and out-of-plane displacements and phase-shifts between these components are different. Furthermore, these parameters can be considered constant in a narrow frequency band. Therefore, if the vertical and horizontal components of the wave motion are available, it is possible to apply signal processing technique referred to as oblique polarization filter. This operation is based on phase-shifts and amplifications of the in- and out-of-plane components, which results in orthogonal, linearly polarized A0 and S0 waves signals. In this paper the proposed technique will be illustrated using both numerical simulations and experimental data. The simulations of wave propagation were performed using local interaction simulation approach (LISA) assuming isotropic material. The experiments were performed using 3D laser scanning Doppler vibrometer that allowed to capture the in-plane and out-of-plane wave components.

  12. Periodic refractive index modifications inscribed in polymer optical fibre by focussed IR femtosecond pulses

    DEFF Research Database (Denmark)

    Stecher, Matthias; Williams, Robert J.; Bang, Ole

    Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy.......Focussed femtosecond laser pulses were used to inscribe a periodic array of modifications in the core of a polymer optical fibre. Structural and refractive-index modifications have been observed at different pulse energies using DIC microscopy....

  13. A method for simultaneously delineating multiple targets in 3D-FISH using limited channels, lasers, and fluorochromes.

    Science.gov (United States)

    Zhao, F Y; Yang, X; Chen, D Y; Ma, W Y; Zheng, J G; Zhang, X M

    2014-01-01

    Many studies have suggested a link between the spatial organization of genomes and fundamental biological processes such as genome reprogramming, gene expression, and differentiation. Multicolor fluorescence in situ hybridization on three-dimensionally preserved nuclei (3D-FISH), in combination with confocal microscopy, has become an effective technique for analyzing 3D genome structure and spatial patterns of defined nucleus targets including entire chromosome territories and single gene loci. This technique usually requires the simultaneous visualization of numerous targets labeled with different colored fluorochromes. Thus, the number of channels and lasers must be sufficient for the commonly used labeling scheme of 3D-FISH, "one probe-one target". However, these channels and lasers are usually restricted by a given microscope system. This paper presents a method for simultaneously delineating multiple targets in 3D-FISH using limited channels, lasers, and fluorochromes. In contrast to other labeling schemes, this method is convenient and simple for multicolor 3D-FISH studies, which may result in widespread adoption of the technique. Lastly, as an application of the method, the nucleus locations of chromosome territory 18/21 and centromere 18/21/13 in normal human lymphocytes were analyzed, which might present evidence of a radial higher order chromatin arrangement.

  14. 3D PIC simulations of electron beams created via reflection of intense laser light from a water target

    CERN Document Server

    Ngirmang, Gregory K; Feister, Scott; Morrison, John T; Chowdhury, Enam A; Frische, Kyle; Roquemore, W M

    2015-01-01

    We present 3D Particle-in-Cell (PIC) modeling of an ultra-intense laser experiment by the Extreme Light group at the Air Force Research Laboratory (AFRL) using the PIC code LSP. This is the first time PIC simulations have been performed in 3D for this experiment which involves an ultra-intense, short-pulse (30 fs) laser interacting with a water jet target at normal incidence. These 3D PIC simulation results are compared to results from 2D(3$v$) PIC simulations for both $5.4\\cdot10^{17}$ W cm$^{-2}$ and $3\\cdot10^{18}$ W cm$^{-2}$ intensities. Comparing the 2D(3$v$) and 3D simulation results, the laser-energy-to-ejected-electron-energy conversion efficiencies were comparable, but the angular distribution of ejected electrons show interesting differences with qualitative differences at higher intensity. An analytic plane-wave model is provided that provides some explanation for the angular distribution and energies of ejected electrons in the 2D(3$v$) simulations. We also performed a 3D simulation with circular...

  15. Comparison of conventional study model measurements and 3D digital study model measurements from laser scanned dental impressions

    Science.gov (United States)

    Nugrahani, F.; Jazaldi, F.; Noerhadi, N. A. I.

    2017-08-01

    The field of orthodontics is always evolving,and this includes the use of innovative technology. One type of orthodontic technology is the development of three-dimensional (3D) digital study models that replace conventional study models made by stone. This study aims to compare the mesio-distal teeth width, intercanine width, and intermolar width measurements between a 3D digital study model and a conventional study model. Twelve sets of upper arch dental impressions were taken from subjects with non-crowding teeth. The impressions were taken twice, once with alginate and once with polivinylsiloxane. The alginate impressions used in the conventional study model and the polivinylsiloxane impressions were scanned to obtain the 3D digital study model. Scanning was performed using a laser triangulation scanner device assembled by the School of Electrical Engineering and Informatics at the Institut Teknologi Bandung and David Laser Scan software. For the conventional model, themesio-distal width, intercanine width, and intermolar width were measured using digital calipers; in the 3D digital study model they were measured using software. There were no significant differences between the mesio-distal width, intercanine width, and intermolar width measurments between the conventional and 3D digital study models (p>0.05). Thus, measurements using 3D digital study models are as accurate as those obtained from conventional study models

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

    Science.gov (United States)

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

    2012-11-01

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

  17. Estimating mass properties of dinosaurs using laser imaging and 3D computer modelling.

    Science.gov (United States)

    Bates, Karl T; Manning, Phillip L; Hodgetts, David; Sellers, William I

    2009-01-01

    Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR) and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize that future

  18. Estimating mass properties of dinosaurs using laser imaging and 3D computer modelling.

    Directory of Open Access Journals (Sweden)

    Karl T Bates

    Full Text Available Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize

  19. Ship-in-a-bottle integration by hybrid femtosecond laser technology for fabrication of true 3D biochips

    Science.gov (United States)

    Sima, Felix; Wu, Dong; Xu, Jian; Midorikawa, Katsumi; Sugioka, Koji

    2015-03-01

    We propose herein the "ship-in-a-bottle" integration of three-dimensional (3D) polymeric sinusoidal ridges inside photosensitive glass microfluidic channel by a hybrid subtractive - additive femtosecond laser processing method. It consists of Femtosecond Laser Assisted Wet Etching (FLAE) of a photosensitive Foturan glass followed by Two-Photon Polymerization (TPP) of a SU-8 negative epoxy-resin. Both subtractive and additive processes are carried out using the same set-up with the change of laser focusing objective only. A 522 nm wavelength of the second harmonic generation from an amplified femtosecond Yb-fiber laser (FCPA µJewel D-400, IMRA America, 1045 nm; pulse width 360 fs, repetition rate 200 kHz) was employed for irradiation. The new method allows lowering the size limit of 3D objects created inside channels to smaller details down to the dimensions of a cell, and improve the structure stability. Sinusoidal periodic patterns and ridges are of great use as base scaffolds for building up new structures on their top or for modulating cell migration, guidance and orientation while created interspaces can be exploited for microfluidic applications. The glass microchannel offers robustness and appropriate dynamic flow conditions for cellular studies while the integrated patterns are reducing the size of structure to the level of cells responsiveness. Taking advantage of the ability to directly fabricate 3D complex shapes, both glass channels and polymeric integrated patterns enable us to 3D spatially design biochips for specific applications.

  20. Accurate 3D comparison of complex topography with terrestrial laser scanner: application to the Rangitikei canyon (N-Z)

    CERN Document Server

    Lague, Dimitri; Leroux, Jérôme

    2013-01-01

    Surveying techniques such as Terrestrial Laser Scanner have recently been used to measure surface changes via 3D point cloud (PC) comparison. Two types of approaches have been pursued: 3D tracking of homologous parts of the surface to compute a displacement field, and distance calculation between two point clouds when homologous parts cannot be defined. This study deals with the second approach, typical of natural surfaces altered by erosion, sedimentation or vegetation between surveys. Current comparison methods are based on a closest point distance or require at least one of the PC to be meshed with severe limitations when surfaces present roughness elements at all scales. We introduce a new algorithm performing a direct comparison of point clouds in 3D. Surface normals are first estimated in 3D at a scale consistent with the local surface roughness. The measurement of the mean change along the normal direction is then performed with an explicit calculation of a confidence interval. Comparison with existing...

  1. Combination of thermal extrusion printing and ultrafast laser fabrication for the manufacturing of 3D composite scaffolds

    Science.gov (United States)

    Balčiūnas, Evaldas; Lukoševičius, Laurynas; Mackevičiūtė, Dovilė; Rekštytė, Sima; Rutkūnas, Vygandas; Paipulas, Domas; Stankevičiūtė, Karolina; Baltriukienė, Daiva; Bukelskienė, Virginija; Piskarskas, Algis P.; Malinauskas, Mangirdas

    2014-03-01

    We present a novel approach to manufacturing 3D microstructured composite scaffolds for tissue engineering applications. A thermal extrusion 3D printer - a simple, low-cost tabletop device enabling rapid materialization of CAD models in plastics - was used to produce cm-scale microporous scaffolds out of polylactic acid (PLA). The fabricated objects were subsequently immersed in a photosensitive monomer solution and direct laser writing technique (DLW) was used to refine its inner structure by fabricating a fine mesh inside the previously produced scaffold. In addition, a composite material structure out of four different materials fabricated via DLW is presented. This technique, empowered by ultrafast lasers allows 3D structuring with high spatial resolution in a great variety of photosensitive materials. A composite scaffold made of distinct materials and periodicities is acquired after the development process used to wash out non-linked monomers. Another way to modify the 3D printed PLA surfaces was also demonstrated - ablation with femtosecond laser beam. Structure geometry on macro- to micro- scales could be finely tuned by combining these fabrication techniques. Such artificial 3D substrates could be used for cell growth or as biocompatible-biodegradable implants. To our best knowledge, this is the first experimental demonstration showing the creation of composite 3D scaffolds using convenient 3D printing combined with DLW. This combination of distinct material processing techniques enables rapid fabrication of diverse functional micro-featured and integrated devices. Hopefully, the proposed approach will find numerous applications in the field of tissue engineering, as well as in microelectromechanical systems, microfluidics, microoptics and others.

  2. Enabling Lorentz boosted frame particle-in-cell simulations of laser wakefield acceleration in quasi-3D geometry

    Science.gov (United States)

    Yu, Peicheng; Xu, Xinlu; Davidson, Asher; Tableman, Adam; Dalichaouch, Thamine; Li, Fei; Meyers, Michael D.; An, Weiming; Tsung, Frank S.; Decyk, Viktor K.; Fiuza, Frederico; Vieira, Jorge; Fonseca, Ricardo A.; Lu, Wei; Silva, Luis O.; Mori, Warren B.

    2016-07-01

    When modeling laser wakefield acceleration (LWFA) using the particle-in-cell (PIC) algorithm in a Lorentz boosted frame, the plasma is drifting relativistically at βb c towards the laser, which can lead to a computational speedup of ∼ γb2 = (1 - βb2)-1. Meanwhile, when LWFA is modeled in the quasi-3D geometry in which the electromagnetic fields and current are decomposed into a limited number of azimuthal harmonics, speedups are achieved by modeling three dimensional (3D) problems with the computational loads on the order of two dimensional r - z simulations. Here, we describe a method to combine the speedups from the Lorentz boosted frame and quasi-3D algorithms. The key to the combination is the use of a hybrid Yee-FFT solver in the quasi-3D geometry that significantly mitigates the Numerical Cerenkov Instability (NCI) which inevitably arises in a Lorentz boosted frame due to the unphysical coupling of Langmuir modes and EM modes of the relativistically drifting plasma in these simulations. In addition, based on the space-time distribution of the LWFA data in the lab and boosted frame, we propose to use a moving window to follow the drifting plasma, instead of following the laser driver as is done in the LWFA lab frame simulations, in order to further reduce the computational loads. We describe the details of how the NCI is mitigated for the quasi-3D geometry, the setups for simulations which combine the Lorentz boosted frame, quasi-3D geometry, and the use of a moving window, and compare the results from these simulations against their corresponding lab frame cases. Good agreement is obtained among these sample simulations, particularly when there is no self-trapping, which demonstrates it is possible to combine the Lorentz boosted frame and the quasi-3D algorithms when modeling LWFA. We also discuss the preliminary speedups achieved in these sample simulations.

  3. Permanent 3D laser scanning system for an active landslide in Gresten (Austria)

    Science.gov (United States)

    Canli, Ekrem; Höfle, Bernhard; Hämmerle, Martin; Benni, Thiebes; Glade, Thomas

    2015-04-01

    Terrestrial laser scanners (TLS) have widely been used for high spatial resolution data acquisition of topographic features and geomorphic analyses. Existing applications encompass different landslides including rockfall, translational or rotational landslides, debris flow, but also coastal cliff erosion, braided river evolution or river bank erosion. The main advantages of TLS are (a) the high spatial sampling density of XYZ-measurements (e.g. 1 point every 2-3 mm at 10 m distance), particularly in comparison with the low data density monitoring techniques such as GNSS or total stations, (b) the millimeter accuracy and precision of the range measurement to centimeter accuracy of the final DEM, and (c) the highly dense area-wide scanning that enables to look through vegetation and to measure bare ground. One of its main constraints is the temporal resolution of acquired data due to labor costs and time requirements for field campaigns. Thus, repetition measurements are generally performed only episodically. However, for an increased scientific understanding of the processes as well as for early warning purposes, we present a novel permanent 3D monitoring setup to increase the temporal resolution of TLS measurements. This accounts for different potential monitoring deliverables such as volumetric calculations, spatio-temporal movement patterns, predictions and even alerting. This system was installed at the active Salcher landslide in Gresten (Austria) that is situated in the transition zone of the Gresten Klippenbelt (Helvetic) and the Flyschzone (Penninic). The characteristic lithofacies are the Gresten Beds of Early Jurassic age that are covered by a sequence of marly and silty beds with intercalated sandy limestones. Permanent data acquisition can be implemented into our workflow with any long-range TLS system offering fully automated capturing. We utilize an Optech ILRIS-3D scanner. The time interval between two scans is currently set to 24 hours, but can be

  4. A generative statistical approach to automatic 3D building roof reconstruction from laser scanning data

    Science.gov (United States)

    Huang, Hai; Brenner, Claus; Sester, Monika

    2013-05-01

    This paper presents a generative statistical approach to automatic 3D building roof reconstruction from airborne laser scanning point clouds. In previous works, bottom-up methods, e.g., points clustering, plane detection, and contour extraction, are widely used. Due to the data artefacts caused by tree clutter, reflection from windows, water features, etc., the bottom-up reconstruction in urban areas may suffer from a number of incomplete or irregular roof parts. Manually given geometric constraints are usually needed to ensure plausible results. In this work we propose an automatic process with emphasis on top-down approaches. The input point cloud is firstly pre-segmented into subzones containing a limited number of buildings to reduce the computational complexity for large urban scenes. For the building extraction and reconstruction in the subzones we propose a pure top-down statistical scheme, in which the bottom-up efforts or additional data like building footprints are no more required. Based on a predefined primitive library we conduct a generative modeling to reconstruct roof models that fit the data. Primitives are assembled into an entire roof with given rules of combination and merging. Overlaps of primitives are allowed in the assembly. The selection of roof primitives, as well as the sampling of their parameters, is driven by a variant of Markov Chain Monte Carlo technique with specified jump mechanism. Experiments are performed on data-sets of different building types (from simple houses, high-rise buildings to combined building groups) and resolutions. The results show robustness despite the data artefacts mentioned above and plausibility in reconstruction.

  5. Fs-laser microstructuring of laser-printed LiMn2O4 electrodes for manufacturing of 3D microbatteries

    Science.gov (United States)

    Pröll, J.; Kim, H.; Mangang, M.; Seifert, H. J.; Piqué, A.; Pfleging, W.

    2014-03-01

    Lithium manganese oxide composite cathodes are realized by laser-printing. The printed cathode is a composite and consists of active powder, binder and conductive agents. Laser-printed cathodes are first calendered and then laser structured using femtosecond-laser radiation in order to form three-dimensional (3D) micro-grids in the cathode material. Three-dimensional micro-grids in calendered/laser structured cathodes exhibit improved discharge capacity retention at a 1 C discharging rate. Calendered but unstructured cathodes indicate the poorest cycling behavior at 1 C discharge. The improved capacity retention and the reduced degradation of calendered/structured cathodes can be attributed to both the increased electrical contact through calendering as well as shortened Li-ion pathways due to laser-induced 3D microgrids.

  6. Technical Note: Reliability of Suchey-Brooks and Buckberry-Chamberlain methods on 3D visualizations from CT and laser scans

    DEFF Research Database (Denmark)

    Villa, Chiara; Buckberry, Jo; Cattaneo, Cristina;

    2013-01-01

    Previous studies have reported that the ageing method of Suchey-Brooks (pubic bone) and some of the features applied by Lovejoy et al. and Buckberry-Chamberlain (auricular surface) can be confidently performed on 3D visualizations from CT-scans. In this study, seven observers applied the Suchey......-Brooks and the Buckberry-Chamberlain methods on 3D visualizations based on CT-scans and, for the first time, on 3D visualizations from laser scans. We examined how the bone features can be evaluated on 3D visualizations and whether the different modalities (direct observations of bones, 3D visualization from CT......-scan and from laser scans) are alike to different observers. We found the best inter-observer agreement for the bones versus 3D visualizations, with the highest values for the auricular surface. Between the 3D modalities, less variability was obtained for the 3D laser visualizations. Fair inter...

  7. Single-shot 3D structure determination of nanocrystals with femtosecond X-ray free electron laser pulses

    CERN Document Server

    Xu, Rui; Song, Changyong; Rodriguez, Jose A; Huang, Zhifeng; Chen, Chien-Chun; Nam, Daewoong; Park, Jaehyun; Gallagher-Jones, Marcus; Kim, Sangsoo; Kim, Sunam; Suzuki, Akihiro; Takayama, Yuki; Oroguchi, Tomotaka; Takahashi, Yukio; Fan, Jiadong; Zou, Yunfei; Hatsui, Takaki; Inubushi, Yuichi; Kameshima, Takashi; Yonekura, Koji; Tono, Kensuke; Togashi, Tadashi; Sato, Takahiro; Yamamoto, Masaki; Nakasako, Masayoshi; Yabashi, Makina; Ishikawa, Tetsuya; Miao, Jianwei

    2013-01-01

    Coherent diffraction imaging (CDI) using synchrotron radiation, X-ray free electron lasers (X-FELs), high harmonic generation, soft X-ray lasers, and optical lasers has found broad applications across several disciplines. An active research direction in CDI is to determine the structure of single particles with intense, femtosecond X-FEL pulses based on diffraction-before-destruction scheme. However, single-shot 3D structure determination has not been experimentally realized yet. Here we report the first experimental demonstration of single-shot 3D structure determination of individual nanocrystals using ~10 femtosecond X-FEL pulses. Coherent diffraction patterns are collected from high-index-faceted nanocrystals, each struck by a single X-FEL pulse. Taking advantage of the symmetry of the nanocrystal, we reconstruct the 3D structure of each nanocrystal from a single-shot diffraction pattern at ~5.5 nm resolution. As symmetry exists in many nanocrystals and virus particles, this method can be applied to 3D st...

  8. Femtosecond laser aided processing of optical sensor fibers for 3D medical navigation and tracking (FiberNavi)

    Science.gov (United States)

    Waltermann, Christian; Koch, Jan; Angelmahr, Martin; Schade, Wolfgang; Witte, Michael; Kohn, Nils; Wilhelm, Dirk; Schneider, Armin; Reiser, Silvano; Feußner, Hubertus

    2014-05-01

    A new concept for fiber-optical 3D shape sensing applying femtosecond laser technology for highprecision direct writing of Bragg gratings within the core and the cladding of single core standard telecom fibers is presented. This new technology enables a cost-efficient and real-time 3D shape sensing and navigation of medical catheters or endoscopes only by means of passive optical sensor elements. First prototypes showed the possibility to achieve absolute navigation accuracy of four mm per meter and have successfully been tested in clinical environment.

  9. Accuracy and precision of the three-dimensional assessment of the facial surface using a 3-D laser scanner.

    Science.gov (United States)

    Kovacs, L; Zimmermann, A; Brockmann, G; Baurecht, H; Schwenzer-Zimmerer, K; Papadopulos, N A; Papadopoulos, M A; Sader, R; Biemer, E; Zeilhofer, H F

    2006-06-01

    Three-dimensional (3-D) recording of the surface of the human body or anatomical areas has gained importance in many medical specialties. Thus, it is important to determine scanner precision and accuracy in defined medical applications and to establish standards for the recording procedure. Here we evaluated the precision and accuracy of 3-D assessment of the facial area with the Minolta Vivid 910 3D Laser Scanner. We also investigated the influence of factors related to the recording procedure and the processing of scanner data on final results. These factors include lighting, alignment of scanner and object, the examiner, and the software used to convert measurements into virtual images. To assess scanner accuracy, we compared scanner data to those obtained by manual measurements on a dummy. Less than 7% of all results with the scanner method were outside a range of error of 2 mm when compared to corresponding reference measurements. Accuracy, thus, proved to be good enough to satisfy requirements for numerous clinical applications. Moreover, the experiments completed with the dummy yielded valuable information for optimizing recording parameters for best results. Thus, under defined conditions, precision and accuracy of surface models of the human face recorded with the Minolta Vivid 910 3D Scanner presumably can also be enhanced. Future studies will involve verification of our findings using test persons. The current findings indicate that the Minolta Vivid 910 3D Scanner might be used with benefit in medicine when recording the 3-D surface structures of the face.

  10. Marginal Accuracy and Internal Fit of 3-D Printing Laser-Sintered Co-Cr Alloy Copings

    Directory of Open Access Journals (Sweden)

    Myung-Joo Kim

    2017-01-01

    Full Text Available Laser sintered technology has been introduced for clinical use and can be utilized more widely, accompanied by the digitalization of dentistry and the development of direct oral scanning devices. This study was performed with the aim of comparing the marginal accuracy and internal fit of Co-Cr alloy copings fabricated by casting, CAD/CAM (Computer-aided design/Computer-assisted manufacture milled, and 3-D laser sintered techniques. A total of 36 Co-Cr alloy crown-copings were fabricated from an implant abutment. The marginal and internal fit were evaluated by measuring the weight of the silicone material, the vertical marginal discrepancy using a microscope, and the internal gap in the sectioned specimens. The data were statistically analyzed by One-way ANOVA (analysis of variance, a Scheffe’s test, and Pearson’s correlation at the significance level of p = 0.05, using statistics software. The silicone weight was significantly low in the casting group. The 3-D laser sintered group showed the highest vertical discrepancy, and marginal-, occlusal-, and average- internal gaps (p < 0.05. The CAD/CAM milled group revealed a significantly high axial internal gap. There are moderate correlations between the vertical marginal discrepancy and the internal gap variables (r = 0.654, except for the silicone weight. In this study, the 3-D laser sintered group achieved clinically acceptable marginal accuracy and internal fit.

  11. 3D digitization methods based on laser excitation and active triangulation: a comparison

    Science.gov (United States)

    Aubreton, Olivier; Mériaudeau, Fabrice; Truchetet, Frédéric

    2016-04-01

    3D reconstruction of surfaces is an important topic in computer vision and corresponds to a large field of applications: industrial inspection, reverse engineering, object recognition, biometry, archeology… Because of the large varieties of applications, one can find in the literature a lot of approaches which can be classified into two families: passive and active [1]. Certainly because of their reliability, active approaches, using imaging system with an additional controlled light source, seem to be the most commonly used in the industrial field. In this domain, the 3D digitization approach based on active 3D triangulation has had important developments during the last ten years [2] and seems to be mature today if considering the important number of systems proposed by manufacturers. Unfortunately, the performances of active 3D scanners depend on the optical properties of the surface to digitize. As an example, on Fig 1.a, a 3D shape with a diffuse surface has been digitized with Comet V scanner (Steinbichler). The 3D reconstruction is presented on Fig 1.b. The same experiment was carried out on a similar object (same shape) but presenting a specular surface (Fig 1.c and Fig 1.d) ; it can clearly be observed, that the specularity influences of the performance of the digitization.

  12. A review on powder-based additive manufacturing for tissue engineering: selective laser sintering and inkjet 3D printing

    Science.gov (United States)

    Shirazi, Seyed Farid Seyed; Gharehkhani, Samira; Mehrali, Mehdi; Yarmand, Hooman; Metselaar, Hendrik Simon Cornelis; Adib Kadri, Nahrizul; Osman, Noor Azuan Abu

    2015-01-01

    Since most starting materials for tissue engineering are in powder form, using powder-based additive manufacturing methods is attractive and practical. The principal point of employing additive manufacturing (AM) systems is to fabricate parts with arbitrary geometrical complexity with relatively minimal tooling cost and time. Selective laser sintering (SLS) and inkjet 3D printing (3DP) are two powerful and versatile AM techniques which are applicable to powder-based material systems. Hence, the latest state of knowledge available on the use of AM powder-based techniques in tissue engineering and their effect on mechanical and biological properties of fabricated tissues and scaffolds must be updated. Determining the effective setup of parameters, developing improved biocompatible/bioactive materials, and improving the mechanical/biological properties of laser sintered and 3D printed tissues are the three main concerns which have been investigated in this article. PMID:27877783

  13. Simultaneous acquisition of 3D shape and deformation by combination of interferometric and correlation-based laser speckle metrology.

    Science.gov (United States)

    Dekiff, Markus; Berssenbrügge, Philipp; Kemper, Björn; Denz, Cornelia; Dirksen, Dieter

    2015-12-01

    A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object's macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured.

  14. A review on powder-based additive manufacturing for tissue engineering: selective laser sintering and inkjet 3D printing.

    Science.gov (United States)

    Shirazi, Seyed Farid Seyed; Gharehkhani, Samira; Mehrali, Mehdi; Yarmand, Hooman; Metselaar, Hendrik Simon Cornelis; Adib Kadri, Nahrizul; Osman, Noor Azuan Abu

    2015-06-01

    Since most starting materials for tissue engineering are in powder form, using powder-based additive manufacturing methods is attractive and practical. The principal point of employing additive manufacturing (AM) systems is to fabricate parts with arbitrary geometrical complexity with relatively minimal tooling cost and time. Selective laser sintering (SLS) and inkjet 3D printing (3DP) are two powerful and versatile AM techniques which are applicable to powder-based material systems. Hence, the latest state of knowledge available on the use of AM powder-based techniques in tissue engineering and their effect on mechanical and biological properties of fabricated tissues and scaffolds must be updated. Determining the effective setup of parameters, developing improved biocompatible/bioactive materials, and improving the mechanical/biological properties of laser sintered and 3D printed tissues are the three main concerns which have been investigated in this article.

  15. FEM Simulation of Dissimilar Aluminum Titanium Fiber Laser Welding Using 2D and 3D Gaussian Heat Sources

    Directory of Open Access Journals (Sweden)

    Sonia D’Ostuni

    2017-08-01

    Full Text Available For a dissimilar laser weld, the model of the heat source is a paramount boundary condition for the prediction of the thermal phenomena, which occur during the welding cycle. In this paper, both two-dimensional (2D and three-dimensional (3D Gaussian heat sources were studied for the thermal analysis of the fiber laser welding of titanium and aluminum dissimilar butt joint. The models were calibrated comparing the fusion zone of the experiment with that of the numerical model. The actual temperature during the welding cycle was registered by a thermocouple and used for validation of the numerical model. When it came to calculate the fusion zone dimensions in the transversal section, the 2D heat source showed more accurate results. The 3D heat source provided better results for the simulated weld pool and cooling rate.

  16. The effect of porosity on cell ingrowth into accurately defined, laser-made, polylactide-based 3D scaffolds

    Energy Technology Data Exchange (ETDEWEB)

    Danilevicius, Paulius; Georgiadi, Leoni [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece); Pateman, Christopher J.; Claeyssens, Frederik [Kroto Research Institute, Department of Materials Science and Engineering, University of Sheffield, Broad Lane, Sheffield S3 7HQ (United Kingdom); Chatzinikolaidou, Maria, E-mail: mchatzin@materials.uoc.gr [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece); Department of Materials Science and Technology, University of Crete, PO Box 2208, 71303 Heraklion (Greece); Farsari, Maria, E-mail: mfarsari@iesl.forth.gr [Foundation for Research and Technology Hellas (FORTH), Institute of Electronic Structure and Laser (IESL), N Plastira 100, 70013 Heraklion (Greece)

    2015-05-01

    Highlights: • We studied the porosity of laser-made 3D scaffolds on MC3T3-E1 pre-osteoblastic cells. • We made polylactide 3D scaffolds with pores 25–110 μm. - Abstract: The aim of this study is to demonstrate the accuracy required for the investigation of the role of solid scaffolds’ porosity in cell proliferation. We therefore present a qualitative investigation into the effect of porosity on MC3T3-E1 pre-osteoblastic cell ingrowth of three-dimensional (3D) scaffolds fabricated by direct femtosecond laser writing. The material we used is a purpose made photosensitive pre-polymer based on polylactide. We designed and fabricated complex, geometry-controlled 3D scaffolds with pore sizes ranging from 25 to 110 μm, representing porosities 70%, 82%, 86%, and 90%. The 70% porosity scaffolds did not support cell growth initially and in the long term. For the other porosities, we found a strong adhesion of the pre-osteoblastic cells from the first hours after seeding and a remarkable proliferation increase after 3 weeks and up to 8 weeks. The 86% porosity scaffolds exhibited a higher efficiency compared to 82% and 90%. In addition, bulk material degradation studies showed that the employed, highly-acrylated polylactide is degradable. These findings support the potential use of the proposed material and the scaffold fabrication technique in bone tissue engineering.

  17. 3D finite element model for writing long-period fiber gratings by CO2 laser radiation.

    Science.gov (United States)

    Coelho, João M P; Nespereira, Marta; Abreu, Manuel; Rebordão, José

    2013-08-12

    In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber's material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation) is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented.

  18. 3D Finite Element Model for Writing Long-Period Fiber Gratings by CO2 Laser Radiation

    Directory of Open Access Journals (Sweden)

    José Rebordão

    2013-08-01

    Full Text Available In the last years, mid-infrared radiation emitted by CO2 lasers has become increasing popular as a tool in the development of long-period fiber gratings. However, although the development and characterization of the resulting sensing devices have progressed quickly, further research is still necessary to consolidate functional models, especially regarding the interaction between laser radiation and the fiber’s material. In this paper, a 3D finite element model is presented to simulate the interaction between laser radiation and an optical fiber and to determine the resulting refractive index change. Dependence with temperature of the main parameters of the optical fiber materials (with special focus on the absorption of incident laser radiation is considered, as well as convection and radiation losses. Thermal and residual stress analyses are made for a standard single mode fiber, and experimental results are presented.

  19. Integration of an optical fiber taper with an optical microresonator fabricated in glass by femtosecond laser 3D micromachining

    CERN Document Server

    Song, Jiangxin; Tang, Jialei; Qiao, Lingling; Cheng, Ya

    2014-01-01

    We report on fabrication of a microtoroid resonator of a high-quality factor (i. e., Q-factor of ~3.24x10^6 measured under the critical coupling condition) using femtosecond laser three-dimensional (3D) micromachining. Coupling of light into and out of the microresonator has been realized with a fiber taper that is reliably assembled with the microtoroid. The assembly of the fiber taper to the microtoroid is achieved by welding the fiber taper onto the sidewall of the microtoroid using CO2 laser irradiation. The integrated microresonator maintains a high Q-factor of 3.21x10^5 as measured in air.

  20. Marginal Accuracy and Internal Fit of 3-D Printing Laser-Sintered Co-Cr Alloy Copings

    OpenAIRE

    Myung-Joo Kim; Yun-Jung Choi; Seong-Kyun Kim; Seong-Joo Heo; Jai-Young Koak

    2017-01-01

    Laser sintered technology has been introduced for clinical use and can be utilized more widely, accompanied by the digitalization of dentistry and the development of direct oral scanning devices. This study was performed with the aim of comparing the marginal accuracy and internal fit of Co-Cr alloy copings fabricated by casting, CAD/CAM (Computer-aided design/Computer-assisted manufacture) milled, and 3-D laser sintered techniques. A total of 36 Co-Cr alloy crown-copings were fabricated from...

  1. Automated 3D Scene Reconstruction from Open Geospatial Data Sources: Airborne Laser Scanning and a 2D Topographic Database

    OpenAIRE

    Lingli Zhu; Matti Lehtomäki; Juha Hyyppä; Eetu Puttonen; Anssi Krooks; Hannu Hyyppä

    2015-01-01

    Open geospatial data sources provide opportunities for low cost 3D scene reconstruction. In this study, based on a sparse airborne laser scanning (ALS) point cloud (0.8 points/m2) obtained from open source databases, a building reconstruction pipeline for CAD building models was developed. The pipeline includes voxel-based roof patch segmentation, extraction of the key-points representing the roof patch outline, step edge identification and adjustment, and CAD building model generation. The a...

  2. 3-D TECATE/BREW: Thermal, stress, and birefringent ray-tracing codes for solid-state laser design

    Science.gov (United States)

    Gelinas, R. J.; Doss, S. K.; Nelson, R. G.

    1994-07-01

    This report describes the physics, code formulations, and numerics that are used in the TECATE (totally Eulerian code for anisotropic thermo-elasticity) and BREW (birefringent ray-tracing of electromagnetic waves) codes for laser design. These codes resolve thermal, stress, and birefringent optical effects in 3-D stationary solid-state systems. This suite of three constituent codes is a package referred to as LASRPAK.

  3. Experimental investigation and 3D-simulation of the ablated morphology of titanium surface using femtosecond laser pulses

    Science.gov (United States)

    Liu, Dong; Chen, Chuansong; Man, Baoyuan; Meng, Xue; Sun, Yanna; Li, Feifei

    2015-12-01

    The femtosecond laser ablated morphology on titanium surface is investigated theoretically and experimentally. A three dimensional two temperature model (3D-TTM) is used to simulate the surface morphology of titanium sample which is irradiated by femtosecond laser pulses. The electron heat capacity and electron-phonon coupling coefficient of titanium (transition metal) are complex temperature dependent, so the two parameters are corrected based on the theory of electron density of states (DOS). The model is solved by the finite difference time domain (FDTD) method. The 3D temperature field near the target surface is achieved. The radius and depth of the ablated crater are obtained based on the temperature field. The evolutions of the crate's radius and depth with laser fluence are discussed and compared with the experimental results. It is found that the back-flow of the molten material and the deposition of the material vapor should be responsible for the little discrepancy between the simulated and experimental results. The present work makes a better understanding of the thermodynamic process of femtosecond laser ablating metal and meanwhile provides an effective method tool to predict the micro manufacturing process on metals with femtosecond laser.

  4. SEE-THROUGH IMAGING OF LASER-SCANNED 3D CULTURAL HERITAGE OBJECTS BASED ON STOCHASTIC RENDERING OF LARGE-SCALE POINT CLOUDS

    OpenAIRE

    Tanaka, S.; Hasegawa, K.; Okamoto, N.; R. Umegaki; Wang, S; M. Uemura(Hiroshima Astrophysical Science Center, Hiroshima University); Okamoto, A; Koyamada, K.

    2016-01-01

    We propose a method for the precise 3D see-through imaging, or transparent visualization, of the large-scale and complex point clouds acquired via the laser scanning of 3D cultural heritage objects. Our method is based on a stochastic algorithm and directly uses the 3D points, which are acquired using a laser scanner, as the rendering primitives. This method achieves the correct depth feel without requiring depth sorting of the rendering primitives along the line of sight. Eliminatin...

  5. SYDESCO: a laser-video scanner for 3D scoliosis evaluations.

    Science.gov (United States)

    Treuillet, S; Lucas, Y; Crepin, G; Peuchot, B; Pichaud, J C

    2002-01-01

    SYDESCO is a new 3D vision system developed for trunk surface topography. This structured light surface scanner uses the principle of triangulation-based range sensing to infer 3D shape. The complete trunk acquisition is fast (2 seconds). The accuracy of the metric data is ensured by a subpixel image detection and a calibration process, which rectifies image deformations. A preliminary study presents results on 50 children in a gymnastics school. These children, aged between eight to sixteen years, are particularly exposed to spinal deformities. An asymmetry index is calculated from the 3D data to detect the pathologic cases. These results have been compared to an independent medical diagnosis. The system results have been confirmed for 72,1% of the patients.

  6. A 3D Analysis of Rock Block Deformation and Failure Mechanics Using Terrestrial Laser Scanning

    Science.gov (United States)

    Rowe, Emily; Hutchinson, D. Jean; Kromer, Ryan A.; Edwards, Tom

    2017-04-01

    Many natural geological hazards are present along the Thompson River corridor in British Columbia, Canada, including one particularly hazardous rocky slope known as the White Canyon. Railway tracks used by Canadian National (CN) and Canadian Pacific (CP) Railway companies pass through this area at the base of the Canyon slope. The geologically complex and weathered rock face exposed at White Canyon is prone to rockfalls. With a limited ditch capacity, these falling rocks have the potential to land on the tracks and therefore increase the risk of train derailment. Since 2012, terrestrial laser scanning (TLS) data has been collected at this site on a regular basis to enable researchers at Queen's University to study these rockfalls in greater detail. In this paper, the authors present a summary of an analysis of these TLS datasets including an examination of the pre-failure deformation patterns exhibited by failed rock blocks as well as an investigation into the influence of structural constraints on the pre-failure behavior of these blocks. Aligning rockfall source zones in an early point cloud dataset to a later dataset generates a transformation matrix describing the movement of the block from one scan to the next. This process was repeated such that the motion of the block over the entire TLS data coverage period was measured. A 3D roto-translation algorithm was then used to resolve the motion into translation and rotation components (Oppikofer et al. 2009; Kromer et al. 2015). Structural information was plotted on a stereonet for further analysis. A total of 111 rockfall events exceeding a volume of 1 m3 were analyzed using this approach. The study reveals that although some rockfall source blocks blocks do not exhibit detectable levels of deformation prior to failure, others do experience cm-level translation and rotation on the order of 1 to 6 degrees before detaching from the slope. Moreover, these movements may, in some cases, be related to the discontinuity

  7. Calibration of Short Range 2D Laser Range Finder for 3D SLAM Usage

    OpenAIRE

    Petr Olivka; Michal Krumnikl; Pavel Moravec; David Seidl

    2016-01-01

    The laser range finder is one of the most essential sensors in the field of robotics. The laser range finder provides an accurate range measurement with high angular resolution. However, the short range scanners require an additional calibration to achieve the abovementioned accuracy. The calibration procedure described in this work provides an estimation of the internal parameters of the laser range finder without requiring any special three-dimensional targets. This work presents the use of...

  8. See-Through Imaging of Laser-Scanned 3d Cultural Heritage Objects Based on Stochastic Rendering of Large-Scale Point Clouds

    Science.gov (United States)

    Tanaka, S.; Hasegawa, K.; Okamoto, N.; Umegaki, R.; Wang, S.; Uemura, M.; Okamoto, A.; Koyamada, K.

    2016-06-01

    We propose a method for the precise 3D see-through imaging, or transparent visualization, of the large-scale and complex point clouds acquired via the laser scanning of 3D cultural heritage objects. Our method is based on a stochastic algorithm and directly uses the 3D points, which are acquired using a laser scanner, as the rendering primitives. This method achieves the correct depth feel without requiring depth sorting of the rendering primitives along the line of sight. Eliminating this need allows us to avoid long computation times when creating natural and precise 3D see-through views of laser-scanned cultural heritage objects. The opacity of each laser-scanned object is also flexibly controllable. For a laser-scanned point cloud consisting of more than 107 or 108 3D points, the pre-processing requires only a few minutes, and the rendering can be executed at interactive frame rates. Our method enables the creation of cumulative 3D see-through images of time-series laser-scanned data. It also offers the possibility of fused visualization for observing a laser-scanned object behind a transparent high-quality photographic image placed in the 3D scene. We demonstrate the effectiveness of our method by applying it to festival floats of high cultural value. These festival floats have complex outer and inner 3D structures and are suitable for see-through imaging.

  9. Laser printing and femtosecond laser structuring of electrode materials for the manufacturing of 3D lithium-ion micro-batteries

    Science.gov (United States)

    Smyrek, P.; Kim, H.; Zheng, Y.; Seifert, H. J.; Piqué, A.; Pfleging, W.

    2016-04-01

    Recently, three-dimensional (3D) electrode architectures have attracted great interest for the development of lithium-ion micro-batteries applicable for Micro-Electro-Mechanical Systems (MEMS), sensors, and hearing aids. Since commercial available micro-batteries are mainly limited in overall cell capacity by their electrode footprint, new processing strategies for increasing both capacity and electrochemical performance have to be developed. In case of such standard microbatteries, two-dimensional (2D) electrode arrangements are applied with thicknesses up to 200 μm. These electrode layers are composed of active material, conductive agent, graphite, and polymeric binder. Nevertheless, with respect to the type of active material, the active material to conductive agent ratio, and the film thickness, such thick-films suffer from low ionic and electronic conductivities, poor electrolyte accessibility, and finally, limited electrochemical performance under challenging conditions. In order to overcome these drawbacks, 3D electrode arrangements are under intense investigation since they allow the reduction of lithium-ion diffusion pathways in between inter-digitated electrodes, even for electrodes with enhanced mass loadings. In this paper, we present how to combine laser-printing and femtosecond laser-structuring for the development of advanced 3D electrodes composed of Li(Ni1/3Mn1/3Co1/3)O2 (NMC). In a first step, NMC thick-films were laser-printed and calendered to achieve film thicknesses in the range of 50 μm - 80 μm. In a second step, femtosecond laser-structuring was carried out in order to generate 3D architectures directly into thick-films. Finally, electrochemical cycling of laser-processed films was performed in order to evaluate the most promising 3D electrode designs suitable for application in long life-time 3D micro-batteries.

  10. 2D and 3D interconnect fabrication by picosecond Laser Induced Forward Transfer

    NARCIS (Netherlands)

    Oosterhuis, G.; Huis in 't veld, A.J.; Chall, P.

    2011-01-01

    Interconnects are an important cost driver in advanced 3D chip packaging. This holds for Through Silicon Vias (TSV) for chip stacking, but also for other integrated Si-technology. Especially in applications with a low number (<100 mm-2) of relatively large (10-2- um diameter), high aspect ratio (1:5

  11. 2D and 3D interconnect fabrication by picosecond Laser Induced Forward Transfer

    NARCIS (Netherlands)

    Oosterhuis, G.; Huis in 't veld, A.J.; Chall, P.

    2011-01-01

    Interconnects are an important cost driver in advanced 3D chip packaging. This holds for Through Silicon Vias (TSV) for chip stacking, but also for other integrated Si-technology. Especially in applications with a low number (<100 mm-2) of relatively large (10-2- um diameter), high aspect ratio

  12. 2D and 3D interconnect fabrication by picosecond Laser Induced Forward Transfer

    NARCIS (Netherlands)

    Oosterhuis, G.; Huis in 't veld, A.J.; Chall, P.

    2011-01-01

    Interconnects are an important cost driver in advanced 3D chip packaging. This holds for Through Silicon Vias (TSV) for chip stacking, but also for other integrated Si-technology. Especially in applications with a low number (<100 mm-2) of relatively large (10-2- um diameter), high aspect ratio (1:5

  13. The Building 3D modeling method Based on 3D Laser Scanning Technology%基于三维激光扫描技术的建筑物三维建模方法

    Institute of Scientific and Technical Information of China (English)

    吕翠华; 陈秀萍; 张东明

    2012-01-01

    Taking TOPCON GLS1500 scanner as an experimental equipment, 3D building modeling method using 3D laser scanning technology is discussed from data acquisition, point cloud processing, 3D modeling and texture mapping etc.%以拓普康GLLS1500扫描仪作为实验设备,从数据采集、点云处理、三维模型建立和纹理映射等方面探讨了利用三维激光扫描技术进行建筑物三维建模的方法.

  14. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel †

    Science.gov (United States)

    Moisan, Emmanuel; Charbonnier, Pierre; Foucher, Philippe; Grussenmeyer, Pierre; Guillemin, Samuel; Koehl, Mathieu

    2015-01-01

    In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part) and sonar (for its underwater part) scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology. PMID:26690444

  15. Adjustment of Sonar and Laser Acquisition Data for Building the 3D Reference Model of a Canal Tunnel

    Directory of Open Access Journals (Sweden)

    Emmanuel Moisan

    2015-12-01

    Full Text Available In this paper, we focus on the construction of a full 3D model of a canal tunnel by combining terrestrial laser (for its above-water part and sonar (for its underwater part scans collected from static acquisitions. The modeling of such a structure is challenging because the sonar device is used in a narrow environment that induces many artifacts. Moreover, the location and the orientation of the sonar device are unknown. In our approach, sonar data are first simultaneously denoised and meshed. Then, above- and under-water point clouds are co-registered to generate directly the full 3D model of the canal tunnel. Faced with the lack of overlap between both models, we introduce a robust algorithm that relies on geometrical entities and partially-immersed targets, which are visible in both the laser and sonar point clouds. A full 3D model, visually promising, of the entrance of a canal tunnel is obtained. The analysis of the method raises several improvement directions that will help with obtaining more accurate models, in a more automated way, in the limits of the involved technology.

  16. Laser Fabrication of 3D Gelatin Scaffolds for the Generation of Bioartificial Tissues

    Directory of Open Access Journals (Sweden)

    Mathias Wilhelmi

    2011-01-01

    Full Text Available In the present work, the two-photon polymerization (2PP technique was applied to develop precisely defined biodegradable 3D tissue engineering scaffolds. The scaffolds were fabricated via photopolymerization of gelatin modified with methacrylamide moieties. The results indicate that the gelatin derivative (GelMod preserves its enzymatic degradation capability after photopolymerization. In addition, the developed scaffolds using 2PP support primary adipose-derived stem cell (ASC adhesion, proliferation and differentiation into the anticipated lineage.

  17. Model-Free 3D Reconstruction of Weld Joint Using Laser Scanning

    OpenAIRE

    Keshmiri, Soheil; Ahmed, Syeda Mariam; Wu, Yue; Chew, Chee Meng; Pang, Chee Khiang

    2014-01-01

    This article presents a novel utilization of the concept of entropy in information theory to model-free 3D reconstruction of weld joint in presence of noise. We show that our formulation attains its global minimum at the upper edge of this joint. This property significantly simplifies the extraction of this welding joint. Furthermore, we present an approach to compute the volume of this extracted space to facilitate the monitoring of the progress of the welding task. Moreover, we provide a pr...

  18. Analysis of thin baked-on silicone layers by FTIR and 3D-Laser Scanning Microscopy.

    Science.gov (United States)

    Funke, Stefanie; Matilainen, Julia; Nalenz, Heiko; Bechtold-Peters, Karoline; Mahler, Hanns-Christian; Friess, Wolfgang

    2015-10-01

    Pre-filled syringes (PFS) and auto-injection devices with cartridges are increasingly used for parenteral administration. To assure functionality, silicone oil is applied to the inner surface of the glass barrel. Silicone oil migration into the product can be minimized by applying a thin but sufficient layer of silicone oil emulsion followed by thermal bake-on versus spraying-on silicone oil. Silicone layers thicker than 100nm resulting from regular spray-on siliconization can be characterized using interferometric profilometers. However, the analysis of thin silicone layers generated by bake-on siliconization is more challenging. In this paper, we have evaluated Fourier transform infrared (FTIR) spectroscopy after solvent extraction and a new 3D-Laser Scanning Microscopy (3D-LSM) to overcome this challenge. A multi-step solvent extraction and subsequent FTIR spectroscopy enabled to quantify baked-on silicone levels as low as 21-325μg per 5mL cartridge. 3D-LSM was successfully established to visualize and measure baked-on silicone layers as thin as 10nm. 3D-LSM was additionally used to analyze the silicone oil distribution within cartridges at such low levels. Both methods provided new, highly valuable insights to characterize the siliconization after processing, in order to achieve functionality.

  19. Automated 3D Scene Reconstruction from Open Geospatial Data Sources: Airborne Laser Scanning and a 2D Topographic Database

    Directory of Open Access Journals (Sweden)

    Lingli Zhu

    2015-05-01

    Full Text Available Open geospatial data sources provide opportunities for low cost 3D scene reconstruction. In this study, based on a sparse airborne laser scanning (ALS point cloud (0.8 points/m2 obtained from open source databases, a building reconstruction pipeline for CAD building models was developed. The pipeline includes voxel-based roof patch segmentation, extraction of the key-points representing the roof patch outline, step edge identification and adjustment, and CAD building model generation. The advantages of our method lie in generating CAD building models without the step of enforcing the edges to be parallel or building regularization. Furthermore, although it has been challenging to use sparse datasets for 3D building reconstruction, our result demonstrates the great potential in such applications. In this paper, we also investigated the applicability of open geospatial datasets for 3D road detection and reconstruction. Road central lines were acquired from an open source 2D topographic database. ALS data were utilized to obtain the height and width of the road. A constrained search method (CSM was developed for road width detection. The CSM method was conducted by splitting a given road into patches according to height and direction criteria. The road edges were detected patch by patch. The road width was determined by the average distance from the edge points to the central line. As a result, 3D roads were reconstructed from ALS and a topographic database.

  20. Frequency-Stable Offset-Locked Lasers for ASCENDS and 3D Winds Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose the potential to develop significant improvements to size, weight, and prime power requirements of front-end cw lasers and associated frequency...

  1. 3D Imaging of Nanoparticle Distribution in Biological Tissue by Laser-Induced Breakdown Spectroscopy

    National Research Council Canada - National Science Library

    Gimenez, Y; Busser, B; Trichard, F; Kulesza, A; Laurent, J M; Zaun, V; Lux, F; Benoit, J M; Panczer, G; Dugourd, P; Tillement, O; Pelascini, F; Sancey, L; Motto-Ros, V

    2016-01-01

    .... The technology used is known as laser-induced breakdown spectroscopy (LIBS) and possesses several advantages such as speed of operation, ease of use and full compatibility with optical microscopy...

  2. Suspect Height Estimation Using the Faro Focus(3D) Laser Scanner.

    Science.gov (United States)

    Johnson, Monique; Liscio, Eugene

    2015-11-01

    At present, very little research has been devoted to investigating the ability of laser scanning technology to accurately measure height from surveillance video. The goal of this study was to test the accuracy of one particular laser scanner to estimate suspect height from video footage. The known heights of 10 individuals were measured using an anthropometer. The individuals were then recorded on video walking along a predetermined path in a simulated crime scene environment both with and without headwear. The difference between the known heights and the estimated heights obtained from the laser scanner software were compared using a one-way t-test. The height estimates obtained from the software were not significantly different from the known heights whether individuals were wearing headwear (p = 0.186) or not (p = 0.707). Thus, laser scanning is one technique that could potentially be used by investigators to determine suspect height from video footage.

  3. 3-D numerical analysis of a high-gain free-electron laser

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, J.C.

    1988-10-19

    We present a novel approach to the 3-dimensional high-gain free- electron laser amplifier problem. The method allows us to write the laser field as an integral equation which can be efficiently and accurately evaluated on a small computer. The model is general enough to allow the inclusion of various initial electron beam distributions to study the gain reduction mechanism and its dependence on the physical parameters. 16 refs., 8 figs., 1 tab.

  4. Time-dependent 3-D modelling of laser surface heating for the hardening of metallic materials

    Science.gov (United States)

    Colombo, V.; Mentrelli, A.; Trombetti, T.

    2003-12-01

    A numerical code for the time-dependent three-dimensional modelling of the laser surface heating for the hardening of metallic materials has been developed by the authors. The temperature-dependence of the thermal properties of the material (stainless steel) is taken into account in the frame of a heating process that doesn’t lead to material melting or evaporation. Calculations have been carried out for various dimensions of the parallelepiped-shaped and of the square-shaped spot of the laser beam, as well as for different scanning velocity and for different levels of the laser source power. Various patterns of the laser spot path have also been studied, including a single-pass hardening pattern, a double-pass hardening pattern with and without overlapping, multiple discontinuous and continuous hardening patterns and spiral hardening patterns. The presented results show how the proposed model can be usefully employed in the prediction of the time-evolution of temperature distribution which arises in the workpiece as a consequence of the laser-workpiece interaction under operating conditions typically encountered in industrial applications of the laser hardening process.

  5. Automatic construction of 3D basic-semantic models of inhabited interiors using laser scanners and RFID sensors.

    Science.gov (United States)

    Valero, Enrique; Adan, Antonio; Cerrada, Carlos

    2012-01-01

    This paper is focused on the automatic construction of 3D basic-semantic models of inhabited interiors using laser scanners with the help of RFID technologies. This is an innovative approach, in whose field scarce publications exist. The general strategy consists of carrying out a selective and sequential segmentation from the cloud of points by means of different algorithms which depend on the information that the RFID tags provide. The identification of basic elements of the scene, such as walls, floor, ceiling, windows, doors, tables, chairs and cabinets, and the positioning of their corresponding models can then be calculated. The fusion of both technologies thus allows a simplified 3D semantic indoor model to be obtained. This method has been tested in real scenes under difficult clutter and occlusion conditions, and has yielded promising results.

  6. ROMY - The First Large 3D Ring Laser Structure for Seismology and Geodesy

    Science.gov (United States)

    Schreiber, Karl Ulrich; Igel, Heiner; Wassermann, Joachim; Lin, Chin-Jen; Gebauer, André; Wells, Jon-Paul

    2016-04-01

    Large ring laser gyroscopes have matured to the point that they can routinely observe rotational motions from geophysical processes that can be used in geodesy and seismology. The ring lasers used for this purpose enclose areas between 16 and 800 square meters and have in common that they can only measure rotations around the vertical axis because the structures are horizontally placed on the floor. With the ROMY project we have embarked on the construction of a full 3-dimensional rotation sensor. The actual apparatus consists of four individual triangular ring lasers arranged in the shape of a tetrahedron with 12 m of length on each side. At each corner of the tetrahedron three of the ring lasers are rigidly tied together to the same mechanical reference. The overall size of the installation provides a promising compromise between sensor stability on one side and sensor resolution on the other side. This talk introduces the technical concept of the ROMY ring laser installation and will also briefly outline the requirements for applications in space geodesy.

  7. 3D LASER SCANNING TECHNIQUE FOR THE INSPECTION AND MONITORING OF RAILWAY TUNNELS

    Directory of Open Access Journals (Sweden)

    Han-Mei CHEN

    2015-12-01

    Full Text Available Railway tunnel inspection and monitoring has predominantly been a visual and manual procedure, which is time-consuming and subjective, giving rise to variance in standards and quality. Thus, alternative, novel, automated techniques need to be developed, for more efficient and reliable tunnel examination. The reported research aimed to investigate the application of a laser scanning technique for the inspection of tunnel degradation and structural integrity. The proposed method may either substitute or supplement traditional survey techniques, being more efficient, and contributing thus to the standardisation of tunnel inspections. For the purpose of investigating the applicability and accuracy of laser scanning in tunnels, a set of tunnel lining models was constructed for laboratory tests, with the objective of determining the quality of the imaging. Initial tests were carried out using a performant laser scanner and demonstrated the feasibility of the concept. As a result, refined laboratory models were built, and experiments conducted, to establish the quality and precision of laser scanning imaging, for condition monitoring of tunnels. The experimental results indicate that the laser scanning technique used in this research has high potential for detecting the tunnel condition, monitoring the depth of weathered mortar, spalling bricks etc. with high accuracy in static scanning mode.

  8. A segmentation method for 3D visualization of neurons imaged with a confocal laser scanning microscope

    Science.gov (United States)

    Anderson, Jeffrey R.; Barrett, Steven F.; Wilcox, Michael J.

    2005-04-01

    Our understanding of the world around us is based primarily on three-dimensional information because of the environment in which we live and interact. Medical or biological image information is often collected in the form of two-dimensional, serial section images. As such, it is difficult for the observer to mentally reconstruct the three dimensional features of each object. Although many image rendering software packages allow for 3D views of the serial sections, they lack the ability to segment, or isolate different objects in the data set. Segmentation is the key to creating 3D renderings of distinct objects from serial slice images, like separate pieces to a puzzle. This paper describes a segmentation method for objects recorded with serial section images. The user defines threshold levels and object labels on a single image of the data set that are subsequently used to automatically segment each object in the remaining images of the same data set, while maintaining boundaries between contacting objects. The performance of the algorithm is verified using mathematically defined shapes. It is then applied to the visual neurons of the housefly, Musca domestica. Knowledge of the fly"s visual system may lead to improved machine visions systems. This effort has provided the impetus to develop this segmentation algorithm. The described segmentation method can be applied to any high contrast serial slice data set that is well aligned and registered. The medical field alone has many applications for rapid generation of 3D segmented models from MRI and other medical imaging modalities.

  9. A Feasibility Study of UV Laser Assisted 3D-Atom Probe Analysis of AlGaN/GaN HEMTs

    Science.gov (United States)

    2013-03-05

    Final Report for AOARD Grant-FA2386-11-1-4031 “A feasibility study of UV laser assisted 3D-atom probe analysis of AlGaN/ GaN HEMTs ” March 5...20-06-2011 to 19-06-2012 4. TITLE AND SUBTITLE A feasibility study of UV laser assisted 3D-atom probe analysis of AlGaN/ GaN HEMTs 5a. CONTRACT...gate region (gate metal, interfacial layer and defects, and AlGaN/ GaN epilayers) of an AFRL HEMT using laser assisted 3-D atom probe (3DAP

  10. Multi-user 3D display using a head tracker and RGB laser illumination source

    Science.gov (United States)

    Surman, Phil; Sexton, Ian; Hopf, Klaus; Bates, Richard; Lee, Wing Kai; Buckley, Edward

    2007-05-01

    A glasses-free (auto-stereoscopic) 3D display that will serve several viewers who have freedom of movement over a large viewing region is described. This operates on the principle of employing head position tracking to provide regions referred to as exit pupils that follow the positions ofthe viewers' eyes in order for appropriate left and right images to be seen. A non-intrusive multi-user head tracker controls the light sources of a specially designed backlight that illuminates a direct-view LCD.

  11. Development of 3D control of a tiny dew droplet by scattered laser light

    Science.gov (United States)

    Matsumoto, Shigeaki

    2009-06-01

    In order to study dropwise condensation on a metal plate, the method for controlling a tiny dew droplet deposited on a copper plate has been developed by using scattered laser light. The method employed the proportional control combined with shifting movement by an integrator to control the intensity of the scattered laser light constantly. Also, the control simulation of the method has been developed to confirm the usefulness of the method and the simulated three-dimensional shape of controlled dew droplet was obtained with the control action. A tiny thin dew droplet, of which the diameter was of handreds micrometers and the mass was about 10-7 g, was controlled in the atmosphere at room temperature for 60 minutes at the preset level of the intensity of scattered laser light and the three-dimensional shape of the controlled dew droplet was shown from the interference fringes.

  12. Calibration of Short Range 2D Laser Range Finder for 3D SLAM Usage

    Directory of Open Access Journals (Sweden)

    Petr Olivka

    2016-01-01

    Full Text Available The laser range finder is one of the most essential sensors in the field of robotics. The laser range finder provides an accurate range measurement with high angular resolution. However, the short range scanners require an additional calibration to achieve the abovementioned accuracy. The calibration procedure described in this work provides an estimation of the internal parameters of the laser range finder without requiring any special three-dimensional targets. This work presents the use of a short range URG-04LX scanner for mapping purposes and describes its calibration. The precision of the calibration was checked in an environment with known ground truth values and the results were statistically evaluated. The benefits of the calibration are also demonstrated in the practical applications involving the segmentation of the environment. The proposed calibration method is complex and detects all major manufacturing inaccuracies. The procedure is suitable for easy integration into the current manufacturing process.

  13. Femtosecond laser 3D micromachining and its applications to biochip fabrication

    Science.gov (United States)

    Sugioka, Koji

    2014-03-01

    Femtosecond lasers have opened up new avenues in materials processing due to their unique characteristics of ultra-short pulse widths and extremely high peak intensities that induce strong absorption in even transparent materials due to nonlinear multiphoton absorption. Then, the femtosecond laser can directly fabricate three-dimensional microfluidic, micromechanic, microelectronic, and micro-optical components in glass. These microcomponents can be easily integrated in a single glass microchip, which enable us to fabricate functional biochips quickly screening large number of biological analytes. In this talk, the detailed fabrication procedure of biochips using the femtosecond laser and applications of the fabricated biochips to material synthesis, analysis of biochemical samples, and determination of functions of microorganisms are introduced.

  14. 3D plasmonic transducer based on gold nanoparticles produced by laser ablation on silica nanowires

    Science.gov (United States)

    Gontad, F.; Caricato, A. P.; Manera, M. G.; Colombelli, A.; Resta, V.; Taurino, A.; Cesaria, M.; Leo, C.; Convertino, A.; Klini, A.; Perrone, A.; Rella, R.; Martino, M.

    2016-05-01

    Silica two-dimensional substrates and nanowires (NWs) forests have been successfully decorated with Au nanoparticles (NPs) through laser ablation by using a pulsed ArF excimer laser, for sensor applications. A uniform coverage of both substrate surfaces with NPs has been achieved controlling the number of laser pulses. The annealing of the as-deposited particles resulted in a uniform well-defined distribution of spherical NPs with an increased average diameter up to 25 nm. The deposited samples on silica NWs forest present a very good plasmonic resonance which resulted to be very sensitive to the changes of the environment (ethanol/water solutions with increasing concentration of ethanol) allowing the detection of changes on the second decimal digit of the refractive index, demonstrating its potentiality for further biosensing functionalities.

  15. Printing Functional 3D Microdevices by Laser-Induced Forward Transfer

    NARCIS (Netherlands)

    Luo, Jun; Pohl, Ralph; Qi, Lehua; Römer, Gerardus Richardus, Bernardus, Engelina; Sun, Chao; Lohse, Detlef; Visser, C.W.

    2017-01-01

    Slender, out-of-plane metal microdevices are made in a new spatial domain, by using laser-induced forward transfer (LIFT) of metals. Here, a thermocouple with a thickness of 10 µm and a height of 250 µm, consisting of platinum and gold pillars is demonstrated. Multimaterial LIFT enables

  16. Printing Functional 3D Microdevices by Laser-Induced Forward Transfer

    NARCIS (Netherlands)

    Luo, Jun; Pohl, Ralph; Qi, Lehua; Römer, Gerardus Richardus, Bernardus, Engelina; Sun, Chao; Lohse, Detlef; Visser, C.W.

    2017-01-01

    Slender, out-of-plane metal microdevices are made in a new spatial domain, by using laser-induced forward transfer (LIFT) of metals. Here, a thermocouple with a thickness of 10 µm and a height of 250 µm, consisting of platinum and gold pillars is demonstrated. Multimaterial LIFT enables manufacturin

  17. Finite element simulation of 3-D laser forming by discrete section ...

    African Journals Online (AJOL)

    ATHARVA

    There is no loading applied on the plate and the self weight is ignored. The laser beam ... The thermal load is given in the form of heat flux that obeys a Gaussian distribution as illustrated in Eq. (5). The traversal .... 8, as a function of angle from.

  18. Printing Functional 3D Microdevices by Laser-Induced Forward Transfer

    NARCIS (Netherlands)

    Luo, Jun; Pohl, Ralph; Qi, Lehua; Römer, Gert-Willem; Sun, Chao; Lohse, Detlef; Visser, Claas Willem

    2017-01-01

    Slender, out-of-plane metal microdevices are made in a new spatial domain, by using laser-induced forward transfer (LIFT) of metals. Here, a thermocouple with a thickness of 10 µm and a height of 250 µm, consisting of platinum and gold pillars is demonstrated. Multimaterial LIFT enables manufacturin

  19. Laser-wakefield accelerators as hard x-ray sources for 3D medical imaging of human bone.

    Science.gov (United States)

    Cole, J M; Wood, J C; Lopes, N C; Poder, K; Abel, R L; Alatabi, S; Bryant, J S J; Jin, A; Kneip, S; Mecseki, K; Symes, D R; Mangles, S P D; Najmudin, Z

    2015-08-18

    A bright μm-sized source of hard synchrotron x-rays (critical energy Ecrit > 30 keV) based on the betatron oscillations of laser wakefield accelerated electrons has been developed. The potential of this source for medical imaging was demonstrated by performing micro-computed tomography of a human femoral trabecular bone sample, allowing full 3D reconstruction to a resolution below 50 μm. The use of a 1 cm long wakefield accelerator means that the length of the beamline (excluding the laser) is dominated by the x-ray imaging distances rather than the electron acceleration distances. The source possesses high peak brightness, which allows each image to be recorded with a single exposure and reduces the time required for a full tomographic scan. These properties make this an interesting laboratory source for many tomographic imaging applications.

  20. Laser-wakefield accelerators as hard x-ray sources for 3D medical imaging of human bone

    Science.gov (United States)

    Cole, J. M.; Wood, J. C.; Lopes, N. C.; Poder, K.; Abel, R. L.; Alatabi, S.; Bryant, J. S. J.; Jin, A.; Kneip, S.; Mecseki, K.; Symes, D. R.; Mangles, S. P. D.; Najmudin, Z.

    2015-01-01

    A bright μm-sized source of hard synchrotron x-rays (critical energy Ecrit > 30 keV) based on the betatron oscillations of laser wakefield accelerated electrons has been developed. The potential of this source for medical imaging was demonstrated by performing micro-computed tomography of a human femoral trabecular bone sample, allowing full 3D reconstruction to a resolution below 50 μm. The use of a 1 cm long wakefield accelerator means that the length of the beamline (excluding the laser) is dominated by the x-ray imaging distances rather than the electron acceleration distances. The source possesses high peak brightness, which allows each image to be recorded with a single exposure and reduces the time required for a full tomographic scan. These properties make this an interesting laboratory source for many tomographic imaging applications. PMID:26283308

  1. A 3D Polymer Based Printed Two-Dimensional Laser Scanner

    Science.gov (United States)

    Oyman, H. A.; Gokdel, Y. D.; Ferhanoglu, O.; Yalcinkaya, A. D.

    2016-10-01

    A two-dimensional (2D) polymer based scanning mirror with magnetic actuation is developed for imaging applications. Proposed device consists of a circular suspension holding a rectangular mirror and can generate a 2D scan pattern. Three dimensional (3D) printing technology which is used for implementation of the device, offers added flexibility in controlling the cross-sectional profile as well as the stress distribution compared to the traditional planar process technologies. The mirror device is developed to meet a portable, miniaturized confocal microscope application in mind, delivering 4.5 and 4.8 degrees of optical scan angles at 111 and 267 Hz, respectively. As a result of this mechanical performance, the resulting microscope incorporating the mirror is estimated to accomplish a field of view (FOV) of 350 µm × 350 µm.

  2. 3D printed facial laser scans for the production of localised radiotherapy treatment masks - A case study.

    Science.gov (United States)

    Briggs, Matthew; Clements, Helen; Wynne, Neil; Rennie, Allan; Kellett, Darren

    This study investigates the use of 3D printing for patients that require localised radiotherapy treatment to the face. The current process involves producing a lead mask in order to protect the healthy tissue from the effects of the radiotherapy. The mask is produced by applying a thermoplastic sheet to the patient's face and allowing to set hard. This can then be used as a mould to create a plaster impression of the patient's face. A sheet of lead is then hammered on to the plaster to create a bespoke fitted face mask. This process can be distressing for patients and can be problematic when the patient is required to remain motionless for a prolonged time while the thermoplastic sets. In this study, a 1:1 scale 3D print of a patient's face was generated using a laser scanner. The lead was hammered directly on to the surface of the 3D print in order to create a bespoke fitted treatment mask. This eliminated the thermoplastic moulding stage and significantly reduced the time needed for the patient to be in clinic. The higher definition impression of the the face resulted in a more accurate, better fitting treatment mask.

  3. Historical Photogrammetry and Terrestrial Laser Scanning for the 3d Virtual Reconstruction of Destroyed Structures: a Case Study in Italy

    Science.gov (United States)

    Bitelli, G.; Dellapasqua, M.; Girelli, V. A.; Sbaraglia, S.; Tinia, M. A.

    2017-05-01

    The current dramatic episodes of destruction of archaeological sites have again highlighted the problem of the safeguarding the threatened heritage and, if possible, recovering those damaged by all the armed conflicts of the past. The historical photogrammetry offers the possibility to recover a posteriori the geometrical and material properties of destroyed structures, reconstructing their 3D model to document, study and maintain their memory, until to support their real anastylosis. The presented work is about the 3D reconstruction of the civic tower of the little town of Sant'Alberto, near the city of Ravenna, Italy. The tower, as a symbol of resistance and pride of the town's population, was destroyed in December 1944 by German troops in retaliation, when they were forced to leave the area. A city committee has subsequently collected all the historical evidence concerning the tower, including a series of photographic images that can be used for the photogrammetric reconstruction; the images calibration and orientation have been solved using the geometric information derived by a terrestrial laser scanner survey realized in the area where the tower was originally located. Despite the scarcity and very poor quality of the available images, the conducted photogrammetric procedure has allowed a complete and qualitatively satisfying object reconstruction, also thanks to the use of geometric constraint tools offered by the chosen software. The integration between the obtained model of the old tower and the 3D TLS survey of the square made it possible to reconstruct the ancient situation of the area.

  4. Laser scanner data processing and 3D modeling using a free and open source software

    Energy Technology Data Exchange (ETDEWEB)

    Gabriele, Fatuzzo [Dept. of Industrial and Mechanical Engineering, University of Catania (Italy); Michele, Mangiameli, E-mail: amichele.mangiameli@dica.unict.it; Giuseppe, Mussumeci; Salvatore, Zito [Dept. of Civil Engineering and Architecture, University of Catania (Italy)

    2015-03-10

    The laser scanning is a technology that allows in a short time to run the relief geometric objects with a high level of detail and completeness, based on the signal emitted by the laser and the corresponding return signal. When the incident laser radiation hits the object to detect, then the radiation is reflected. The purpose is to build a three-dimensional digital model that allows to reconstruct the reality of the object and to conduct studies regarding the design, restoration and/or conservation. When the laser scanner is equipped with a digital camera, the result of the measurement process is a set of points in XYZ coordinates showing a high density and accuracy with radiometric and RGB tones. In this case, the set of measured points is called “point cloud” and allows the reconstruction of the Digital Surface Model. Even the post-processing is usually performed by closed source software, which is characterized by Copyright restricting the free use, free and open source software can increase the performance by far. Indeed, this latter can be freely used providing the possibility to display and even custom the source code. The experience started at the Faculty of Engineering in Catania is aimed at finding a valuable free and open source tool, MeshLab (Italian Software for data processing), to be compared with a reference closed source software for data processing, i.e. RapidForm. In this work, we compare the results obtained with MeshLab and Rapidform through the planning of the survey and the acquisition of the point cloud of a morphologically complex statue.

  5. 3D LASER SCANNING TECHNIQUE FOR THE INSPECTION AND MONITORING OF RAILWAY TUNNELS

    OpenAIRE

    2015-01-01

    Railway tunnel inspection and monitoring has predominantly been a visual and manual procedure, which is time-consuming and subjective, giving rise to variance in standards and quality. Thus, alternative, novel, automated techniques need to be developed, for more efficient and reliable tunnel examination. The reported research aimed to investigate the application of a laser scanning technique for the inspection of tunnel degradation and structural integrity. The proposed method may either subs...

  6. Fabrication of 3D components by laser-aided direct metal deposition

    Science.gov (United States)

    Mazumder, Jyotirmoy; Qi, Huan

    2005-03-01

    Breinan and Kear first reported fabrication of three-dimensional metallic components via layer by layer laser cladding in 1978 and subsequently a patent was issued to Brown et al. in 1982. Recently, various groups are working world wide on different types of layered manufacturing techniques for fabrication of near net shape metallic components. Integration of lasers with multi-axis presently available CNC machines, CAD/CAM, sensors and powder metal delivery through co-axial nozzles along with the laser beam are the main innovations for fabrication of 3-Dimensional components. Continuous corrective measures during the manufacturing process are necessary to fabricate net shape functional parts with close tolerances and acceptable residual stress. The closed loop Direct Metal Deposition(DMD) System, using an optical feedback loop along with a CNC working under the instructions from a CAD/CAM software, indicate that it can produce three dimensional components directly from the CAD data eliminating intermediate machining and reduces final machining considerably. This technology is now being commercialized.

  7. 3D model for laser heating of a heterogeneous turbid medium

    Science.gov (United States)

    Rossacci, Michael J.; DiMarzio, Charles A.; Lindberg, Scott C.; Pankratov, Michail M.

    1997-05-01

    In order to better understand the interaction of laser light with biological tissue, a light-transport model is integrated with a heat-transport model. The outputs include temperature as a function of position and time, given the illumination conditions and the optical and thermal properties of the tissue. The optical portion of the algorithm is based on the theory of radiative transfer through a turbid medium. Our computer program models multiple scattering in three dimensions using seven discrete irradiances which approximate the radiative transport equation. The distribution of absorbed light in the tissue is calculated and used as the source term in a discrete approximation to the thermal diffusion equation. Recently, we have been using the model to better understand the laser-heating of heterogeneous tissue. Rather than modeling a homogeneous mixture having properties given by weighted averages of those of tissue and blood, we model this medium as an array of blood vessels in a bloodless dermis background. We are currently analyzing temporal and spatial variations of temperature in homogeneous and heterogeneous tissue having identical blood concentrations. A particular application of the model is to the study of laser coagulation tonsillectomy.

  8. 3D analysis of thermal and stress evolution during laser cladding of bioactive glass coatings.

    Science.gov (United States)

    Krzyzanowski, Michal; Bajda, Szymon; Liu, Yijun; Triantaphyllou, Andrew; Mark Rainforth, W; Glendenning, Malcolm

    2016-06-01

    Thermal and strain-stress transient fields during laser cladding of bioactive glass coatings on the Ti6Al4V alloy basement were numerically calculated and analysed. Conditions leading to micro-cracking susceptibility of the coating have been investigated using the finite element based modelling supported by experimental results of microscopic investigation of the sample coatings. Consecutive temperature and stress peaks are developed within the cladded material as a result of the laser beam moving along the complex trajectory, which can lead to micro-cracking. The preheated to 500°C base plate allowed for decrease of the laser power and lowering of the cooling speed between the consecutive temperature peaks contributing in such way to achievement of lower cracking susceptibility. The cooling rate during cladding of the second and the third layer was lower than during cladding of the first one, in such way, contributing towards improvement of cracking resistance of the subsequent layers due to progressive accumulation of heat over the process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Design and Fabrication of a Breadboard, Fully Conductively Cooled, 2-Micron, Pulsed Laser for the 3-D Winds Decadal Survey Mission Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Design and fabricate a space-qualifiable, fully conductively cooled, 2-micron pulsed laser breadboard meeting the projected 3-D Winds mission requirements. Utilize...

  10. Multitemporal 3D data capturing and GIS analysis of fluvial processes and geomorphological changes with terrestrial laser scanning

    Science.gov (United States)

    Hämmerle, Martin; Forbriger, Markus; Höfle, Bernhard

    2013-04-01

    LiDAR is a state of the art method for directly capturing 3D geodata. A laser beam is emitted in a known direction. The time of flight of the laser pulse is recorded and transformed into the distance between sensor and scanned object. The result of the scanning process is a 3D laser point cloud densely covering the surveyed area. LiDAR is used in a vast variety of research fields. In this study, the focus is on the application of terrestrial laser scanning (TLS), the static and ground-based LiDAR operation, in a multitemporal analysis of fluvial geomorphology. Within the framework of two study projects in 2011/2012, two TLS surveys were carried out. The surveys covered a gravel bar of about 150 m × 25 m size in a side branch of the Neckar River near Heidelberg (49°28'36''N, 8°34'32''E) located in a nature reserve with natural river characteristics. The first survey was performed in November 2011, the second in June 2012. Due to seasonally changing water levels, the gravel bar was flooded and the morphology changed. For the field campaigns, a Riegl VZ-400 was available. Height control points and tie points for registration and georeferencing were obtained with a total station and GPS equipment. The first survey was done from 6 scan positions (77 million points) and the second from 5 positions (89 million points). The point spacing for each single scan was set to 3 mm at 10 m distance. Co-registration of the individual campaigns was done via an Iterative Closest Point algorithm. Thereafter, co-registration and fine georeferencing of both epochs was performed using manually selected tie points and least-squares adjustment. After filtering of vegetation in the 3D point cloud in the software OPALS, a digital terrain model (DTM) with 0.25 m by 0.25 m cell size was generated for each epoch. A difference raster model of the two DTMs for assessing the changes was derived excluding water surface areas using the signal amplitude recorded for each echo. From the mean

  11. Estimation of regeneration coverage in a temperate forest by 3D segmentation using airborne laser scanning data

    Science.gov (United States)

    Amiri, Nina; Yao, Wei; Heurich, Marco; Krzystek, Peter; Skidmore, Andrew K.

    2016-10-01

    Forest understory and regeneration are important factors in sustainable forest management. However, understanding their spatial distribution in multilayered forests requires accurate and continuously updated field data, which are difficult and time-consuming to obtain. Therefore, cost-efficient inventory methods are required, and airborne laser scanning (ALS) is a promising tool for obtaining such information. In this study, we examine a clustering-based 3D segmentation in combination with ALS data for regeneration coverage estimation in a multilayered temperate forest. The core of our method is a two-tiered segmentation of the 3D point clouds into segments associated with regeneration trees. First, small parts of trees (super-voxels) are constructed through mean shift clustering, a nonparametric procedure for finding the local maxima of a density function. In the second step, we form a graph based on the mean shift clusters and merge them into larger segments using the normalized cut algorithm. These segments are used to obtain regeneration coverage of the target plot. Results show that, based on validation data from field inventory and terrestrial laser scanning (TLS), our approach correctly estimates up to 70% of regeneration coverage across the plots with different properties, such as tree height and tree species. The proposed method is negatively impacted by the density of the overstory because of decreasing ground point density. In addition, the estimated coverage has a strong relationship with the overstory tree species composition.

  12. Use of 3D laser radar for navigation of unmanned aerial and ground vehicles in urban and indoor environments

    Science.gov (United States)

    Uijt de Haag, Maarten; Venable, Don; Smearcheck, Mark

    2007-04-01

    This paper discusses the integration of Inertial measurements with measurements from a three-dimensional (3D) imaging sensor for position and attitude determination of unmanned aerial vehicles (UAV) and autonomous ground vehicles (AGV) in urban or indoor environments. To enable operation of UAVs and AGVs at any time in any environment a Precision Navigation, Attitude, and Time (PNAT) capability is required that is robust and not solely dependent on the Global Positioning System (GPS). In urban and indoor environments a GPS position capability may not only be unavailable due to shadowing, significant signal attenuation or multipath, but also due to intentional denial or deception. Although deep integration of GPS and Inertial Measurement Unit (IMU) data may prove to be a viable solution an alternative method is being discussed in this paper. The alternative solution is based on 3D imaging sensor technologies such as Flash Ladar (Laser Radar). Flash Ladar technology consists of a modulated laser emitter coupled with a focal plane array detector and the required optics. Like a conventional camera this sensor creates an "image" of the environment, but producing a 2D image where each pixel has associated intensity vales the flash Ladar generates an image where each pixel has an associated range and intensity value. Integration of flash Ladar with the attitude from the IMU allows creation of a 3-D scene. Current low-cost Flash Ladar technology is capable of greater than 100 x 100 pixel resolution with 5 mm depth resolution at a 30 Hz frame rate. The proposed algorithm first converts the 3D imaging sensor measurements to a point cloud of the 3D, next, significant environmental features such as planar features (walls), line features or point features (corners) are extracted and associated from one 3D imaging sensor frame to the next. Finally, characteristics of these features such as the normal or direction vectors are used to compute the platform position and attitude

  13. Algorithm for Evaluation of Temperature 3D-Distribution of a Vapor Cell in a Diode End-pumped Alkali Laser System

    Science.gov (United States)

    Han, J. H.; Wang, Y.; Cai, H.; An, G. F.; Rong, K. P.; Yu, H.; Wang, S. Y.; Wang, H. Y.; Zhang, W.; Xue, L. P.; Zhou, J.

    2017-06-01

    We develop a new 3D-model to evaluate the light characteristics and the thermal features of a cesium-vapor laser end-pumped by a laser diode. The theoretical model is based on the principles of both heat transfer and laser kinetics. The 3-dimensional population density distribution and temperature distribution are both systematically obtained and analyzed. The methodology is thought to be useful for realization of a high-powered diode-pumped alkali laser (DPAL) in the future.

  14. Differential axial contrast of optical sections: laser microtomography and quantitative 3D reconstruction

    Science.gov (United States)

    Pogorelova, M. A.; Golichenkov, V. A.; Pogorelov, A. G.

    2014-03-01

    Specific features of the quantitative laser microtomography of biological samples are discussed. The method exhibits the main advantages of a confocal microscope (rapid measurement of a stack of parallel optical cross sections and accurate displacement of an object along the optical axis). A relatively high contrast is reached owing to the superposition of pairwise complementary images on neighboring cross sections. A simple and convenient algorithm for image processing does not require additional software and can be computerized using a conventional graphic editor. The applicability of the method is illustrated using volume measurements of a single cell of an early mouse embryo.

  15. Three-dimensional recording of the human face with a 3D laser scanner.

    Science.gov (United States)

    Kovacs, L; Zimmermann, A; Brockmann, G; Gühring, M; Baurecht, H; Papadopulos, N A; Schwenzer-Zimmerer, K; Sader, R; Biemer, E; Zeilhofer, H F

    2006-01-01

    Three-dimensional recording of the surface of the human body or of certain anatomical areas has gained an ever increasing importance in recent years. When recording living surfaces, such as the human face, not only has a varying degree of surface complexity to be accounted for, but also a variety of other factors, such as motion artefacts. It is of importance to establish standards for the recording procedure, which will optimise results and allow for better comparison and validation. In the study presented here, the faces of five male test persons were scanned in different experimental settings using non-contact 3D digitisers, type Minolta Vivid 910). Among others, the influence of the number of scanners used, the angle of recording, the head position of the test person, the impact of the examiner and of examination time on accuracy and precision of the virtual face models generated from the scanner data with specialised software were investigated. Computed data derived from the virtual models were compared to corresponding reference measurements carried out manually between defined landmarks on the test persons' faces. We describe experimental conditions that were of benefit in optimising the quality of scanner recording and the reliability of three-dimensional surface imaging. However, almost 50% of distances between landmarks derived from the virtual models deviated more than 2mm from the reference of manual measurements on the volunteers' faces.

  16. Wavelength-scale light concentrator made by direct 3D laser writing of polymer metamaterials

    Science.gov (United States)

    Moughames, J.; Jradi, S.; Chan, T. M.; Akil, S.; Battie, Y.; Naciri, A. En; Herro, Z.; Guenneau, S.; Enoch, S.; Joly, L.; Cousin, J.; Bruyant, A.

    2016-10-01

    We report on the realization of functional infrared light concentrators based on a thick layer of air-polymer metamaterial with controlled pore size gradients. The design features an optimum gradient index profile leading to light focusing in the Fresnel zone of the structures for two selected operating wavelength domains near 5.6 and 10.4 μm. The metamaterial which consists in a thick polymer containing air holes with diameters ranging from λ/20 to λ/8 is made using a 3D lithography technique based on the two-photon polymerization of a homemade photopolymer. Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer. Such porous and flat metamaterial structures offer interesting perspectives to increase infrared detector performance at the pixel level for imaging or sensing applications.

  17. Wavelength-scale light concentrator made by direct 3D laser writing of polymer metamaterials

    Science.gov (United States)

    Moughames, J.; Jradi, S.; Chan, T. M.; Akil, S.; Battie, Y.; Naciri, A. En; Herro, Z.; Guenneau, S.; Enoch, S.; Joly, L.; Cousin, J.; Bruyant, A.

    2016-01-01

    We report on the realization of functional infrared light concentrators based on a thick layer of air-polymer metamaterial with controlled pore size gradients. The design features an optimum gradient index profile leading to light focusing in the Fresnel zone of the structures for two selected operating wavelength domains near 5.6 and 10.4 μm. The metamaterial which consists in a thick polymer containing air holes with diameters ranging from λ/20 to λ/8 is made using a 3D lithography technique based on the two-photon polymerization of a homemade photopolymer. Infrared imaging of the structures reveals a tight focusing for both structures with a maximum local intensity increase by a factor of 2.5 for a concentrator volume of 1.5 λ3, slightly limited by the residual absorption of the selected polymer. Such porous and flat metamaterial structures offer interesting perspectives to increase infrared detector performance at the pixel level for imaging or sensing applications. PMID:27698476

  18. Multiple Reflections and Fresnel Absorption of Gaussian Laser Beam in an Actual 3D Keyhole during Deep-Penetration Laser Welding

    Directory of Open Access Journals (Sweden)

    Xiangzhong Jin

    2012-01-01

    Full Text Available In deep penetration laser welding, a keyhole is formed in the material. Based on an experimentally obtained bending keyhole from low- and medium-speed laser penetration welding of glass, the keyhole profiles in both the symmetric plane are determined by polynomial fitting. Then, a 3D bending keyhole is reconstructed under the assumption of circular cross-section of the keyhole at each keyhole depth. In this paper, the behavior of focused Gaussian laser beam in the keyhole is analyzed by tracing a ray of light using Gaussian optics theory, the Fresnel absorption and multiple reflections in the keyhole are systematically studied, and the laser intensities absorbed on the keyhole walls are calculated. Finally, the formation mechanism of the keyhole is deduced.

  19. Exact and variational solutions of 3D eigenmodes in high gain FELs [Exact and variational solutions of 3D eigenmodes in high gain free electron lasers

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Ming [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2000-05-18

    Exact solution and variational approximation of eigenmodes in high gain FELs are presented. These eigenmodes specify transverse profiles and exponential growth rates of the laser field before saturation. They are self-consistent solutions of coupled Maxwell–Vlasov equations describing FEL interaction taking into account the effects due to energy spread, emittance and betatron oscillations of the electron beam, as well as diffraction and optical guiding of the laser field. A new formalism of scaling is introduced and based on which solutions in various limiting cases are discussed. Additionally, a fitting formula is obtained from interpolating the variational solution for quick calculation of exponential growth rate of the fundamental mode.

  20. Parallel deconvolution of large 3D images obtained by confocal laser scanning microscopy.

    Science.gov (United States)

    Pawliczek, Piotr; Romanowska-Pawliczek, Anna; Soltys, Zbigniew

    2010-03-01

    Various deconvolution algorithms are often used for restoration of digital images. Image deconvolution is especially needed for the correction of three-dimensional images obtained by confocal laser scanning microscopy. Such images suffer from distortions, particularly in the Z dimension. As a result, reliable automatic segmentation of these images may be difficult or even impossible. Effective deconvolution algorithms are memory-intensive and time-consuming. In this work, we propose a parallel version of the well-known Richardson-Lucy deconvolution algorithm developed for a system with distributed memory and implemented with the use of Message Passing Interface (MPI). It enables significantly more rapid deconvolution of two-dimensional and three-dimensional images by efficiently splitting the computation across multiple computers. The implementation of this algorithm can be used on professional clusters provided by computing centers as well as on simple networks of ordinary PC machines.

  1. Time-resolved fuel injector flow characterisation based on 3D laser Doppler vibrometry

    CERN Document Server

    Crua, Cyril

    2015-01-01

    In order to enable investigations of the fuel flow inside unmodified injectors, we have developed a new experimental approach to measure time-resolved vibration spectra of diesel nozzles using a three dimensional laser vibrometer. The technique we propose is based on the triangulation of the vibrometer and fuel pressure transducer signals, and enables the quantitative characterisation of quasi-cyclic internal flows without requiring modifications to the injector, the working fluid, or limiting the fuel injection pressure. The vibrometer, which uses the Doppler effect to measure the velocity of a vibrating object, was used to scan injector nozzle tips during the injection event. The data were processed using a discrete Fourier transform to provide time-resolved spectra for valve-closed-orifice, minisac and microsac nozzle geometries, and injection pressures ranging from 60 to 160MPa, hence offering unprecedented insight into cyclic cavitation and internal mechanical dynamic processes. A peak was consistently f...

  2. Laser characterisation of a 3D single-type column p-type prototype module read out with ATLAS SCT electronics

    Energy Technology Data Exchange (ETDEWEB)

    Ehrich, T. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Kuehn, S. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany)], E-mail: susanne.kuehn@physik.uni-freiburg.de; Boscardin, M.; Dalla Betta, G.-F. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy); Eckert, S.; Jakobs, K.; Maassen, M.; Parzefall, U. [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder Str. 3, 79104 Freiburg (Germany); Piemonte, C.; Pozza, A.; Ronchin, S.; Zorzi, N. [ITC-irst Trento, Microsystems Division, via Sommarive, 18 38050 Povo di Trento (Italy)

    2007-12-11

    In this paper measurements of a 3D single-type column (3D-stc) microstrip silicon device are shown. The 3D-stc sensor has n-type columns in p-type substrate. It has been connected to an ATLAS SCT ABCD3T chip and is readout with ATLAS SCT electronics at 40 MHz. Spatial measurements were done with a laser setup to investigate the expected low field region in 3D devices. An influence of the p-stops on the collected charge has been observed.

  3. Applications of Non-destructive methods (GPR and 3D Laser Scanner) in Historic Masonry Arch Bridge Assessment

    Science.gov (United States)

    Alani, Amir; Banks, Kevin

    2014-05-01

    There exist approximately 70,000 masonry arch bridge spans (brick and stone) in the UK with tens of thousands more throughout Europe. A significant number of these bridges are still in operation and form part of the road and rail network systems in many countries. A great majority of these bridges are in desperate need of repair and maintenance. Applications of non-destructive testing methods such as ground penetrating radar (GPR), 3D laser scanning, accelerometer sensors and vibration detecting sensors amongst many others have been used to assess and monitor such structures in the past few years. This presentation provides results of the applications of a 2GHz GPR antenna system and a 3D laser scanner on a historic masonry arch bridge (the Old Bridge, Aylesford) located in Kent, in the south east of England. The older part of the bridge (the mid-span) is 860 years old. The bridge was the subject of a major alteration in 1811. This presentation forms part of a larger ongoing study which is using the two above mentioned non-destructive methods for long-term monitoring of the bridge. The adopted survey planning strategy and technique, data acquisition and processing as well as challenges encountered during actual survey and fieldworks have been discussed in this presentation. As a result of this study the position of different layers of the deck structure has been established with the identification of the original stone base of the bridge. This information in addition to the location of a number of structural ties (anchors - remedial work carried out previously) in the absence of reliable and accurate design details proved to be extremely useful for the modelling of the bridge using the finite element method. Results of the 3D laser scanning of the bridge have also been presented which have provided invaluable data essential for the accurate modelling of the bridge as well as the long term monitoring of the bridge. 2014 EGU-GA GI3.1 Session, organised by COST Action

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

    Energy Technology Data Exchange (ETDEWEB)

    Weekes, B.; Ewins, D. [University of Bristol, Queen' s Building, University Walk, Bristol, BS8 1TR (United Kingdom); Acciavatti, F. [Universita' Politecnica Delle Marche, Via Brecce Bianche 12, 60131 Ancona (Italy)

    2014-05-27

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

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

    Science.gov (United States)

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

    2014-05-01

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

  6. 3D digitizing path planning for part inspection with laser scanning

    Science.gov (United States)

    Mahmud, Mussa; Joannic, David; Fontaine, Jean-François

    2007-01-01

    If the first work relating to the automation of the digitalization of machine elements goes back to approximately 25 years, the process of digitalization of parts with non-contact sensor remains nevertheless complex. It is not completely solved today, in particular from a metrological point of view. In this article, we consider the determination of the trajectory planning within the framework of the control of dimensional and geometrical specifications. The sensor used in this application is a laser planner scanner with CCD camera oriented and moved by a CMM. For this purpose, we have focused on the methodology used to determine the best possible viewpoints which will satisfy the digitizing of a mechanical part. The developed method is based on the concept of visibility: for each facet of a part CAD Model (STL) a set of orientations, called real visibility chart, is calculated under condition of measurement uncertainties. By application of several optimisation criteria, the real visibility chart is reduced to create a viewpoint set from which the path planning is built.

  7. Scanning laser optical computed tomography system for large volume 3D dosimetry

    Science.gov (United States)

    Dekker, Kurtis H.; Battista, Jerry J.; Jordan, Kevin J.

    2017-04-01

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  8. Scanning laser optical computed tomography system for large volume 3D dosimetry.

    Science.gov (United States)

    Dekker, Kurtis H; Battista, Jerry J; Jordan, Kevin J

    2017-04-07

    Stray light causes artifacts in optical computed tomography (CT) that negatively affect the accuracy of radiation dosimetry in gels or solids. Scatter effects are exacerbated by a large dosimeter volume, which is desirable for direct verification of modern radiotherapy treatment plans such as multiple-isocenter radiosurgery. The goal in this study was to design and characterize an optical CT system that achieves high accuracy primary transmission measurements through effective stray light rejection, while maintaining sufficient scan speed for practical application. We present an optical imaging platform that uses a galvanometer mirror for horizontal scanning, and a translation stage for vertical movement of a laser beam and small area detector for minimal stray light production and acceptance. This is coupled with a custom lens-shaped optical CT aquarium for parallel ray sampling of projections. The scanner images 15 cm diameter, 12 cm height cylindrical volumes at 0.33 mm resolution in approximately 30 min. Attenuation coefficients reconstructed from CT scans agreed with independent cuvette measurements within 2% for both absorbing and scattering solutions as well as small 1.25 cm diameter absorbing phantoms placed within a large, scattering medium that mimics gel. Excellent linearity between the optical CT scanner and the independent measurement was observed for solutions with between 90% and 2% transmission. These results indicate that the scanner should achieve highly accurate dosimetry of large volume dosimeters in a reasonable timeframe for clinical application to radiotherapy dose verification procedures.

  9. In-process 3D laser measurement to control the fiber tape-laying for composite production

    Science.gov (United States)

    Schmitt, Robert; Mersmann, Christoph; Damm, Björn

    2010-05-01

    Metrology is the key to an economically feasible production of fiber-reinforced composites in the field of automated tape laying, applying a novel laser light-section sensor system (LLSS) to measure process quality and feed back the results to close control loops of the production system. The developed method derives 3D measurements from height profiles through an in-process surface scan by the integrated LLSS. Gaps, overlaps, misalignment and defects of the composite tapes are detected during their lay-up and consolidation by comparing the measurement results with a CAD/CAM model of the lay-up. The height profiles are processed with a novel algorithm based on a non-linear least-square fitting to a set of sigmoid functions to ensure sub-pixel accuracy.

  10. Writing of 3D optical integrated circuits with ultrashort laser pulses in the presence of strong spherical aberration

    Science.gov (United States)

    Bukharin, M. A.; Skryabin, N. N.; Khudyakov, D. V.; Vartapetov, S. K.

    2016-09-01

    A novel technique was proposed for 3D femtosecond writing of waveguides and optical integrated circuits in the presence of strong spherical aberration, caused by inscription at significantly different depth under the surface of optical glasses and crystals. Strong negative effect of spherical aberration and related asymmetry of created structures was reduced due to transition to the cumulative thermal regime of femtosecond interaction with the material. The differences in the influence of spherical aberration effect in a broad depth range (larger than 200 µm) was compensated by dynamic adjustment of laser pulse energy during the process of waveguides recording. The presented approach has been experimentally implemented in fused silica. Obtained results can be used in production of a broad class of femtosecond written three-dimensional integrated optical systems, inscripted at non-optimal (for focusing lens) optical depth or in significantly extended range of depths.

  11. High resolution 3D laser scanner measurements of a strike-slip fault quantify its morphological anisotropy at all scales

    CERN Document Server

    Renard, Francois; Marsan, Davd; Schmittbuhl, Jean

    2008-01-01

    The surface roughness of a recently exhumed strikeslip fault plane has been measured by three independent 3D portable laser scanners. Digital elevation models of several fault surface areas, from 1 m2 to 600 m2, have been measured at a resolution ranging from 5 mm to 80 mm. Out of plane height fluctuations are described by non-Gaussian distribution with exponential long range tails. Statistical scaling analyses show that the striated fault surface exhibits self-affine scaling invariance with a small but significant directional morphological anisotropy that can be described by two scaling roughness exponents, H1 = 0.7 in the direction of slip and H2 = 0.8 perpendicular to the direction of slip.

  12. Hardness and microstructural inhomogeneity at the epitaxial interface of laser 3D-printed Ni-based superalloy

    Science.gov (United States)

    Qian, Dan; Zhang, Anfeng; Zhu, Jianxue; Li, Yao; Zhu, Wenxin; Qi, Baolu; Tamura, Nobumichi; Li, Dichen; Song, Zhongxiao; Chen, Kai

    2016-09-01

    In this letter, microstructural and mechanical inhomogeneities, a great concern for single crystal Ni-based superalloys repaired by laser assisted 3D printing, have been probed near the epitaxial interface. Nanoindentation tests show the hardness to be uniformly lower in the bulk of the substrate and constantly higher in the epitaxial cladding layer. A gradient of hardness through the heat affected zone is also observed, resulting from an increase in dislocation density, as indicated by the broadening of the synchrotron X-ray Laue microdiffraction reflections. The hardening mechanism of the cladding region, on the other hand, is shown to originate not only from high dislocation density but also and more importantly from the fine γ/γ' microstructure.

  13. Phase unwrapping for large depth-of-field 3D laser holographic interferometry measurement of laterally discontinuous surfaces

    Science.gov (United States)

    Huang, Zhenhua; Shih, Albert J.; Ni, Jun

    2006-11-01

    A phase unwrapping method is developed to mathematically increase the depth-of-field for the 3D optical measurement of objects with laterally discontinuous surfaces, which contain disconnected high aspect ratio regions. This method is applied for laser holographic interferometry precision measurements. The phase wrap identification at boundary pixels, masking and recovery, dynamic segmentation and phase adjustment are developed to overcome the divergence problem in phase unwrapping of laterally discontinuous surfaces. An automotive automatic transmission valve body is applied as an example to demonstrate the developed method. Experimental results demonstrate that the proposed methods can efficiently unwrap the phase to increase the depth-of-field for laterally discontinuous surfaces. Effects of segment size and width of overlapped regions on the computational efficiency are investigated.

  14. Frontonasal dysmorphology in bipolar disorder by 3D laser surface imaging and geometric morphometrics: comparisons with schizophrenia.

    LENUS (Irish Health Repository)

    Hennessy, Robin J

    2010-09-01

    Any developmental relationship between bipolar disorder and schizophrenia engenders continuing debate. As the brain and face emerge in embryological intimacy, brain dysmorphogenesis is accompanied by facial dysmorphogenesis. 3D laser surface imaging was used to capture the facial surface of 13 male and 14 female patients with bipolar disorder in comparison with 61 male and 75 female control subjects and with 37 male and 32 female patients with schizophrenia. Surface images were analysed using geometric morphometrics and 3D visualisations to identify domains of facial shape that distinguish bipolar patients from controls and bipolar patients from those with schizophrenia. Both male and female bipolar patients evidenced significant facial dysmorphology: common to male and female patients was overall facial widening, increased width of nose, narrowing of mouth and upward displacement of the chin; dysmorphology differed between male and female patients for nose length, lip thickness and tragion height. There were few morphological differences in comparison with schizophrenia patients. That dysmorphology of the frontonasal prominences and related facial regions in bipolar disorder is more similar to than different from that found in schizophrenia indicates some common dysmorphogenesis. Bipolar disorder and schizophrenia might reflect similar insult(s) acting over slightly differing time-frames or slightly differing insult(s) acting over a similar time-frame.

  15. Optically Clear and Resilient Free-Form μ-Optics 3D-Printed via Ultrafast Laser Lithography

    Science.gov (United States)

    Jonušauskas, Linas; Gailevičius, Darius; Mikoliūnaitė, Lina; Sakalauskas, Danas; Šakirzanovas, Simas; Juodkazis, Saulius; Malinauskas, Mangirdas

    2017-01-01

    We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized) organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL). This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW) and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8) and can sustain up to 1.91 GW/cm2 intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures. PMID:28772389

  16. Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography.

    Science.gov (United States)

    Jonušauskas, Linas; Gailevičius, Darius; Mikoliūnaitė, Lina; Sakalauskas, Danas; Šakirzanovas, Simas; Juodkazis, Saulius; Malinauskas, Mangirdas

    2017-01-02

    We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized) organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL). This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW) and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8) and can sustain up to 1.91 GW/cm² intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures.

  17. Optically Clear and Resilient Free-Form µ-Optics 3D-Printed via Ultrafast Laser Lithography

    Directory of Open Access Journals (Sweden)

    Linas Jonušauskas

    2017-01-01

    Full Text Available We introduce optically clear and resilient free-form micro-optical components of pure (non-photosensitized organic-inorganic SZ2080 material made by femtosecond 3D laser lithography (3DLL. This is advantageous for rapid printing of 3D micro-/nano-optics, including their integration directly onto optical fibers. A systematic study of the fabrication peculiarities and quality of resultant structures is performed. Comparison of microlens resiliency to continuous wave (CW and femtosecond pulsed exposure is determined. Experimental results prove that pure SZ2080 is ∼20 fold more resistant to high irradiance as compared with standard lithographic material (SU8 and can sustain up to 1.91 GW/cm2 intensity. 3DLL is a promising manufacturing approach for high-intensity micro-optics for emerging fields in astro-photonics and atto-second pulse generation. Additionally, pyrolysis is employed to homogeneously shrink structures up to 40% by removing organic SZ2080 constituents. This opens a promising route towards downscaling photonic lattices and the creation of mechanically robust glass-ceramic microstructures.

  18. The effect of porosity on cell ingrowth into accurately defined, laser-made, polylactide-based 3D scaffolds

    Science.gov (United States)

    Danilevicius, Paulius; Georgiadi, Leoni; Pateman, Christopher J.; Claeyssens, Frederik; Chatzinikolaidou, Maria; Farsari, Maria

    2015-05-01

    The aim of this study is to demonstrate the accuracy required for the investigation of the role of solid scaffolds' porosity in cell proliferation. We therefore present a qualitative investigation into the effect of porosity on MC3T3-E1 pre-osteoblastic cell ingrowth of three-dimensional (3D) scaffolds fabricated by direct femtosecond laser writing. The material we used is a purpose made photosensitive pre-polymer based on polylactide. We designed and fabricated complex, geometry-controlled 3D scaffolds with pore sizes ranging from 25 to 110 μm, representing porosities 70%, 82%, 86%, and 90%. The 70% porosity scaffolds did not support cell growth initially and in the long term. For the other porosities, we found a strong adhesion of the pre-osteoblastic cells from the first hours after seeding and a remarkable proliferation increase after 3 weeks and up to 8 weeks. The 86% porosity scaffolds exhibited a higher efficiency compared to 82% and 90%. In addition, bulk material degradation studies showed that the employed, highly-acrylated polylactide is degradable. These findings support the potential use of the proposed material and the scaffold fabrication technique in bone tissue engineering.

  19. Development of kinematic 3D laser scanning system for indoor mapping and as-built BIM using constrained SLAM.

    Science.gov (United States)

    Jung, Jaehoon; Yoon, Sanghyun; Ju, Sungha; Heo, Joon

    2015-10-16

    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.

  20. 3D geometrical inspection of complex geometry parts using a novel laser triangulation sensor and a robot.

    Science.gov (United States)

    Brosed, Francisco Javier; Aguilar, Juan José; Guillomía, David; Santolaria, Jorge

    2011-01-01

    This article discusses different non contact 3D measuring strategies and presents a model for measuring complex geometry parts, manipulated through a robot arm, using a novel vision system consisting of a laser triangulation sensor and a motorized linear stage. First, the geometric model incorporating an automatic simple module for long term stability improvement will be outlined in the article. The new method used in the automatic module allows the sensor set up, including the motorized linear stage, for the scanning avoiding external measurement devices. In the measurement model the robot is just a positioning of parts with high repeatability. Its position and orientation data are not used for the measurement and therefore it is not directly "coupled" as an active component in the model. The function of the robot is to present the various surfaces of the workpiece along the measurement range of the vision system, which is responsible for the measurement. Thus, the whole system is not affected by the robot own errors following a trajectory, except those due to the lack of static repeatability. For the indirect link between the vision system and the robot, the original model developed needs only one first piece measuring as a "zero" or master piece, known by its accurate measurement using, for example, a Coordinate Measurement Machine. The strategy proposed presents a different approach to traditional laser triangulation systems on board the robot in order to improve the measurement accuracy, and several important cues for self-recalibration are explored using only a master piece. Experimental results are also presented to demonstrate the technique and the final 3D measurement accuracy.

  1. 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.

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

    Science.gov (United States)

    Jung, Jaehoon; Yoon, Sanghyun; Ju, Sungha; Heo, Joon

    2015-01-01

    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. PMID:26501292

  3. Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime

    Directory of Open Access Journals (Sweden)

    W. Lu

    2007-06-01

    Full Text Available The extraordinary ability of space-charge waves in plasmas to accelerate charged particles at gradients that are orders of magnitude greater than in current accelerators has been well documented. We develop a phenomenological framework for laser wakefield acceleration (LWFA in the 3D nonlinear regime, in which the plasma electrons are expelled by the radiation pressure of a short pulse laser, leading to nearly complete blowout. Our theory provides a recipe for designing a LWFA for given laser and plasma parameters and estimates the number and the energy of the accelerated electrons whether self-injected or externally injected. These formulas apply for self-guided as well as externally guided pulses (e.g. by plasma channels. We demonstrate our results by presenting a sample particle-in-cell (PIC simulation of a 30   fs, 200 TW laser interacting with a 0.75 cm long plasma with density 1.5×10^{18}  cm^{-3} to produce an ultrashort (10 fs monoenergetic bunch of self-injected electrons at 1.5 GeV with 0.3 nC of charge. For future higher-energy accelerator applications, we propose a parameter space, which is distinct from that described by Gordienko and Pukhov [Phys. Plasmas 12, 043109 (2005PHPAEN1070-664X10.1063/1.1884126] in that it involves lower plasma densities and wider spot sizes while keeping the intensity relatively constant. We find that this helps increase the output electron beam energy while keeping the efficiency high.

  4. Terrestrial and aerial laser scanning data integration using wavelet analysis for the purpose of 3D building modeling.

    Science.gov (United States)

    Kedzierski, Michal; Fryskowska, Anna

    2014-01-01

    Visualization techniques have been greatly developed in the past few years. Three-dimensional models based on satellite and aerial imagery are now being enhanced by models generated using Aerial Laser Scanning (ALS) data. The most modern of such scanning systems have the ability to acquire over 50 points per square meter and to register a multiple echo, which allows the reconstruction of the terrain together with the terrain cover. However, ALS data accuracy is less than 10 cm and the data is often incomplete: there is no information about ground level (in most scanning systems), and often around the facade or structures which have been covered by other structures. However, Terrestrial Laser Scanning (TLS) not only acquires higher accuracy data (1-5 cm) but is also capable of registering those elements which are incomplete or not visible using ALS methods (facades, complicated structures, interiors, etc.). Therefore, to generate a complete 3D model of a building in high Level of Details, integration of TLS and ALS data is necessary. This paper presents the wavelet-based method of processing and integrating data from ALS and TLS. Methods of choosing tie points to combine point clouds in different datum will be analyzed.

  5. Laser processing of SnO2 electrode materials for manufacturing of 3D micro-batteries

    Science.gov (United States)

    Kohler, R.; Proell, J.; Ulrich, S.; Przybylski, M.; Pfleging, W.

    2011-03-01

    The material development for advanced lithium-ion batteries plays an important role in future mobile applications and energy storage systems. It is assumed that electrode materials made of nano-composited materials will improve battery lifetime and will lead to an enhancement of lithium diffusion and thus improve battery capacity and cyclability. A major problem concerning thin film electrodes is, that increasing film thickness leads to an increase in lithium diffusion path lengths and thereby a decrease in power density. To overcome this problem, the investigation of a 3D-battery system with an increased surface area is necessary. UV-laser micromachining was applied to create defined line or grating structures via mask imaging. SnO2 is a highly investigated anode material for lithium-ion batteries. Yet, the enormous volume changes occurring during electrochemical cycling lead to immense loss of capacity. The formation of micropatterns via laser ablation to create structures which enable the compensation of the volume expansion was investigated in detail. Thin films of SnO2 were deposited in Ar:O2 atmosphere via r.f. magnetron sputtering on silicon and stainless steel substrates. The thin films were studied with X-ray diffraction to determine their crystallinity. The electrochemical properties of the manufactured films were investigated via electrochemical cycling against a lithium anode.

  6. 3D nanostructured inkjet printed graphene via UV-pulsed laser irradiation enables paper-based electronics and electrochemical devices.

    Science.gov (United States)

    Das, Suprem R; Nian, Qiong; Cargill, Allison A; Hondred, John A; Ding, Shaowei; Saei, Mojib; Cheng, Gary J; Claussen, Jonathan C

    2016-09-21

    Emerging research on printed and flexible graphene-based electronics is beginning to show tremendous promise for a wide variety of fields including wearable sensors and thin film transistors. However, post-print annealing/reduction processes that are necessary to increase the electrical conductivity of the printed graphene degrade sensitive substrates (e.g., paper) and are whole substrate processes that are unable to selectively anneal/reduce only the printed graphene-leaving sensitive device components exposed to damaging heat or chemicals. Herein a pulsed laser process is introduced that can selectively irradiate inkjet printed reduced graphene oxide (RGO) and subsequently improve the electrical conductivity (Rsheet∼0.7 kΩ□(-1)) of printed graphene above previously published reports. Furthermore, the laser process is capable of developing 3D petal-like graphene nanostructures from 2D planar printed graphene. These visible morphological changes display favorable electrochemical sensing characteristics-ferricyanide cyclic voltammetry with a redox peak separation (ΔEp) ≈ 0.7 V as well as hydrogen peroxide (H2O2) amperometry with a sensitivity of 3.32 μA mM(-1) and a response time of <5 s. Thus this work paves the way for not only paper-based electronics with graphene circuits, it enables the creation of low-cost and disposable graphene-based electrochemical electrodes for myriad applications including sensors, biosensors, fuel cells, and theranostic devices.

  7. Efficient Second Harmonic Generation in 3D Nonlinear Optical-Lattice-Like Cladding Waveguide Splitters by Femtosecond Laser Inscription.

    Science.gov (United States)

    Nie, Weijie; Jia, Yuechen; Vázquez de Aldana, Javier R; Chen, Feng

    2016-02-29

    Integrated photonic devices with beam splitting function are intriguing for a broad range of photonic applications. Through optical-lattice-like cladding waveguide structures fabricated by direct femtosecond laser writing, the light propagation can be engineered via the track-confined refractive index profiles, achieving tailored output beam distributions. In this work, we report on the fabrication of 3D laser-written optical-lattice-like structures in a nonlinear KTP crystal to implement 1 × 4 beam splitting. Second harmonic generation (SHG) of green light through these nonlinear waveguide beam splitter structures provides the capability for the compact visible laser emitting devices. With Type II phase matching of the fundamental wavelength (@ 1064 nm) to second harmonic waves (@ 532 nm), the frequency doubling has been achieved through this three-dimensional beam splitter. Under 1064-nm continuous-wave fundamental-wavelength pump beam, guided-wave SHG at 532 nm are measured with the maximum power of 0.65 mW and 0.48 mW for waveguide splitters (0.67 mW and 0.51 mW for corresponding straight channel waveguides), corresponding to a SH conversion efficiency of approximately ~14.3%/W and 13.9%/W (11.2%/W, 11.3%/W for corresponding straight channel waveguides), respectively. This work paves a way to fabricate compact integrated nonlinear photonic devices in a single chip with beam dividing functions.

  8. ALE-AMR: A new 3D multi-physics code for modeling laser/target effects

    Science.gov (United States)

    Koniges, A. E.; Masters, N. D.; Fisher, A. C.; Anderson, R. W.; Eder, D. C.; Kaiser, T. B.; Bailey, D. S.; Gunney, B.; Wang, P.; Brown, B.; Fisher, K.; Hansen, F.; Maddox, B. R.; Benson, D. J.; Meyers, M.; Geille, A.

    2010-08-01

    We have developed a new 3D multi-physics multi-material code, ALE-AMR, for modeling laser/target effects including debris/shrapnel generation. The code combines Arbitrary Lagrangian Eulerian (ALE) hydrodynamics with Adaptive Mesh Refinement (AMR) to connect the continuum to microstructural regimes. The code is unique in its ability to model hot radiating plasmas and cold fragmenting solids. New numerical techniques were developed for many of the physics packages to work efficiency on a dynamically moving and adapting mesh. A flexible strength/failure framework allows for pluggable material models. Material history arrays are used to store persistent data required by the material models, for instance, the level of accumulated damage or the evolving yield stress in J2 plasticity models. We model ductile metals as well as brittle materials such as Si, Be, and B4C. We use interface reconstruction based on volume fractions of the material components within mixed zones and reconstruct interfaces as needed. This interface reconstruction model is also used for void coalescence and fragmentation. The AMR framework allows for hierarchical material modeling (HMM) with different material models at different levels of refinement. Laser rays are propagated through a virtual composite mesh consisting of the finest resolution representation of the modeled space. A new 2nd order accurate diffusion solver has been implemented for the thermal conduction and radiation transport packages. The code is validated using laser and x-ray driven spall experiments in the US and France. We present an overview of the code and simulation results.

  9. Tunable quantum interference in a 3D integrated circuit.

    Science.gov (United States)

    Chaboyer, Zachary; Meany, Thomas; Helt, L G; Withford, Michael J; Steel, M J

    2015-04-27

    Integrated photonics promises solutions to questions of stability, complexity, and size in quantum optics. Advances in tunable and non-planar integrated platforms, such as laser-inscribed photonics, continue to bring the realisation of quantum advantages in computation and metrology ever closer, perhaps most easily seen in multi-path interferometry. Here we demonstrate control of two-photon interference in a chip-scale 3D multi-path interferometer, showing a reduced periodicity and enhanced visibility compared to single photon measurements. Observed non-classical visibilities are widely tunable, and explained well by theoretical predictions based on classical measurements. With these predictions we extract Fisher information approaching a theoretical maximum. Our results open a path to quantum enhanced phase measurements.

  10. Positional precision evaluation of 3 D laser scanner based on 3 D control field%基于三维控制场的三维激光扫描仪点位精度评定

    Institute of Scientific and Technical Information of China (English)

    史波; 郑敏

    2015-01-01

    为评定三维激光扫描仪的精度,设计了一个基于室内三维控制场的RIEGL VZ-400点位精度评定方案。通过实测得到其在距离10 m左右的外部、内部符合精度分别为±1.675 mm和±0.48 mm。详细介绍了室内全景三维控制场的布设、数据采集以及点位精度的评定方法。研究结果可为地面三维激光扫描仪的工程应用提供精度依据。%For evaluating the precision of a 3D laser scanner, we designed a positional precision evaluation solution for RIEGL VZ-400 on the basis of the 3D indoor panoramic control field. Through the evaluation, the precision of external and internal po-sition at distance of 10 m is ± 1. 675mm and ± 0. 48mm respectively. The layout, data collection way and the positional preci-sion evaluation method are introduced. The results could provide experiences and references for the application of ground 3D laser scanners.

  11. Augmenting comprehension of geological relationships by integrating 3D laser scanned hand samples within a GIS environment

    Science.gov (United States)

    Harvey, A. S.; Fotopoulos, G.; Hall, B.; Amolins, K.

    2017-06-01

    Geological observations can be made on multiple scales, including micro- (e.g. thin section), meso- (e.g. hand-sized to outcrop) and macro- (e.g. outcrop and larger) scales. Types of meso-scale samples include, but are not limited to, rocks (including drill cores), minerals, and fossils. The spatial relationship among samples paired with physical (e.g. granulometric composition, density, roughness) and chemical (e.g. mineralogical and isotopic composition) properties can aid in interpreting geological settings, such as paleo-environmental and formational conditions as well as geomorphological history. Field samples are collected along traverses in the area of interest based on characteristic representativeness of a region, predetermined rate of sampling, and/or uniqueness. The location of a sample can provide relative context in seeking out additional key samples. Beyond labelling and recording of geospatial coordinates for samples, further analysis of physical and chemical properties may be conducted in the field and laboratory. The main motivation for this paper is to present a workflow for the digital preservation of samples (via 3D laser scanning) paired with the development of cyber infrastructure, which offers geoscientists and engineers the opportunity to access an increasingly diverse worldwide collection of digital Earth materials. This paper describes a Web-based graphical user interface developed using Web AppBuilder for ArcGIS for digitized meso-scale 3D scans of geological samples to be viewed alongside the macro-scale environment. Over 100 samples of virtual rocks, minerals and fossils populate the developed geological database and are linked explicitly with their associated attributes, characteristic properties, and location. Applications of this new Web-based geological visualization paradigm in the geosciences demonstrate the utility of such a tool in an age of increasing global data sharing.

  12. Application of 3D triangulations of airborne laser scanning data to estimate boreal forest leaf area index

    Science.gov (United States)

    Majasalmi, Titta; Korhonen, Lauri; Korpela, Ilkka; Vauhkonen, Jari

    2017-07-01

    We propose 3D triangulations of airborne Laser Scanning (ALS) point clouds as a new approach to derive 3D canopy structures and to estimate forest canopy effective LAI (LAIe). Computational geometry and topological connectivity were employed to filter the triangulations to yield a quasi-optimal relationship with the field measured LAIe. The optimal filtering parameters were predicted based on ALS height metrics, emulating the production of maps of LAIe and canopy volume for large areas. The LAIe from triangulations was validated with field measured LAIe and compared with a reference LAIe calculated from ALS data using logarithmic model based on Beer's law. Canopy transmittance was estimated using All Echo Cover Index (ACI), and the mean projection of unit foliage area (β) was obtained using no-intercept regression with field measured LAIe. We investigated the influence species and season on the triangulated LAIe and demonstrated the relationship between triangulated LAIe and canopy volume. Our data is from 115 forest plots located at the southern boreal forest area in Finland and for each plot three different ALS datasets were available to apply the triangulations. The triangulation approach was found applicable for both leaf-on and leaf-off datasets after initial calibration. Results showed the Root Mean Square Errors (RMSEs) between LAIe from triangulations and field measured values agreed the most using the highest pulse density data (RMSE = 0.63, the coefficient of determination (R2) = 0.53). Yet, the LAIe calculated using ACI-index agreed better with the field measured LAIe (RMSE = 0.53 and R2 = 0.70). The best models to predict the optimal alpha value contained the ACI-index, which indicates that within-crown transmittance is accounted by the triangulation approach. The cover indices may be recommended for retrieving LAIe only, but for applications which require more sophisticated information on canopy shape and volume, such as radiative transfer models, the

  13. Application of 3D laser scanner in ore volume measurement%三维激光扫描仪在测算矿方量中的应用

    Institute of Scientific and Technical Information of China (English)

    黄有; 郑坤; 刘修国; 王红平; 阮进成

    2012-01-01

    Recently, with the rapid development of 3D laser scanning technique, 3D laser scanners have been extensively applied in many fields. The paper mainly described the application of 3D laser scanner in ore volume measure. The volume of ore hea Pwas calculated after it was scanned by the Riegl VZ-400 3D laser scanner. The precision was confirmed by the comparison of the control points' geodetic coordinates measured by GPS and scanner coordinates. The result of experiment showed that the precision of 3D laser scanner could satisfy the requirements of ore volume measurement. In conclusion, the paper summarized the advantage of the usage of 3D laser scanning technology in ore volume measurement.%本文通过使用Riegl VZ-400型号的三维激光扫描仪对某矿堆进行了扫描,对扫描数据进行三维建模后测算矿堆的矿方量.采用GPS测量一定数量控制点的大地坐标与扫描仪测量的坐标进行比较来验证扫描数据的精度,得到平面坐标的差值绝对值最大为0 018m,而高程的差值绝对值最大为0.028m,实验结果表明三维激光扫描仪满足测算矿方量的精度.

  14. 3-D laser confocal microscopy study of the oxidation of NdFeB magnets in atmospheric conditions

    Energy Technology Data Exchange (ETDEWEB)

    Meakin, J.P., E-mail: jxm764@bham.ac.uk; Speight, J.D.; Sheridan, R.S.; Bradshaw, A.; Harris, I.R.; Williams, A.J.; Walton, A.

    2016-08-15

    Highlights: • Room temperature atmospheric oxidation behaviour of sintered NdFeB. • 3D laser confocal microscopy measurement of oxide phase growth. • Significant height increase of oxide phase only observed at triple points. • Raman spectroscopy identified oxide phase to be Nd{sub 2}O{sub 3}. • Diffusion coefficient determined to be 4 × 10{sup −13} cm{sup 2}/s. - Abstract: Neodymium iron boron (NdFeB) magnets are used in a number of important applications, such as generators in gearless wind turbines, motors in electric vehicles and electronic goods (e.g.— computer hard disk drives, HDD). Hydrogen can be used as a processing gas to separate and recycle scrap sintered Nd-Fe-B magnets from end-of-life products to form a powder suitable for recycling. However, the magnets are likely to have been exposed to atmospheric conditions prior to processing, and any oxidation could lead to activation problems for the hydrogen decrepitation reaction. Many previous studies on the oxidation of NdFeB magnets have been performed at elevated temperatures; however, few studies have been formed under atmospheric conditions. In this paper a combination of 3-D laser confocal microscopy and Raman spectroscopy have been used to assess the composition, morphology and rate of oxidation/corrosion on scrap sintered NdFeB magnets. Confocal microscopy has been employed to measure the growth of surface reaction products at room temperature, immediately after exposure to air. The results showed that there was a significant height increase at the triple junctions of the Nd-rich grain boundaries. Using Raman spectroscopy, the product was shown to consist of Nd{sub 2}O{sub 3} and formed only on the Nd-rich triple junctions. The diffusion coefficient of the triple junction reaction product growth at 20 °C was determined to be approximately 4 × 10{sup −13} cm{sup 2}/sec. This value is several orders of magnitude larger than values derived from the diffusion controlled oxide growth

  15. Development of a new laser-line and CCD based optical-CT scanner for the readout of 3D radiation dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Papadakis, A E; Maris, T G; Zacharakis, G; Ripoll, J; Varveris, C; Damilakis, J, E-mail: apapadak@edu.med.uoc.g

    2010-11-01

    We present initial results on the comparison of the dose readout from a three dimensional polymer gel dosimeter using two different optical-CT systems; i) a common wide field and a wide area detector optical-CT system and ii) a new 'laser-line' and wide area detector based optical-CT system. The findings presented herein highlight the advantage of the laser based over the wide field optical-CT concept for the readout of scattering 3D dosimeters. Moreover, the new 'laser-line' based optical-CT system overcomes the disadvantage of the long acquisition times required by the existing laser-based instruments.

  16. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    Science.gov (United States)

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-06-01

    Synchrotron-based Laue microdiffraction has been widely applied to characterize the local crystal structure, orientation, and defects of inhomogeneous polycrystalline solids by raster scanning them under a micro/nano focused polychromatic X-ray probe. In a typical experiment, a large number of Laue diffraction patterns are collected, requiring novel data reduction and analysis approaches, especially for researchers who do not have access to fast parallel computing capabilities. In this article, a novel approach is developed by plotting the distributions of the average recorded intensity and the average filtered intensity of the Laue patterns. Visualization of the characteristic microstructural features is realized in real time during data collection. As an example, this method is applied to image key features such as microcracks, carbides, heat affected zone, and dendrites in a laser assisted 3D printed Ni-based superalloy, at a speed much faster than data collection. Such analytical approach remains valid for a wide range of crystalline solids, and therefore extends the application range of the Laue microdiffraction technique to problems where real-time decision-making during experiment is crucial (for instance time-resolved non-reversible experiments).

  17. Guided-wave-based damage detection in a composite T-joint using 3D scanning laser Doppler vibrometer

    Science.gov (United States)

    Kolappan Geetha, Ganesh; Roy Mahapatra, D.; Srinivasan, Gopalakrishnan

    2012-04-01

    Composite T-joints are commonly used in modern composite airframe, pressure vessels and piping structures, mainly to increase the bending strength of the joint and prevents buckling of plates and shells, and in multi-cell thin-walled structures. Here we report a detailed study on the propagation of guided ultrasonic wave modes in a composite T-joint and their interactions with delamination in the co-cured co-bonded flange. A well designed guiding path is employed wherein the waves undergo a two step mode conversion process, one is due to the web and joint filler on the back face of the flange and the other is due to the delamination edges close to underneath the accessible surface of the flange. A 3D Laser Doppler Vibrometer is used to obtain the three components of surface displacements/velocities of the accessible face of the flange of the T-joint. The waves are launched by a piezo ceramic wafer bonded on to the back surface of the flange. What is novel in the proposed method is that the location of any change in material/geometric properties can be traced by computing a frequency domain power flow along a scan line. The scan line can be chosen over a grid either during scan or during post-processing of the scan data off-line. The proposed technique eliminates the necessity of baseline data and disassembly of structure for structural interrogation.

  18. Growth Mechanism and Characterization of ZnO 3D Nanocrystals by Laser Irradiation & Coaxially Transporting O2

    Institute of Scientific and Technical Information of China (English)

    LUO Kaiyu; LI Boquan; ZHANG Huanyan

    2008-01-01

    Different three-dimension (3D) nanotetrapods,containing club-like nanocrystals,nanotetrapods and four-foot-like nanocrystals were synthesized from Zinc sheet via CO2 laser irradiation and coaxially transporting O2.Different nanoproducts were fabricated by changing the content of oxygen in the experiment.The morphologies,components,phase structures and optical properties of the products were investigated by a field-emission scanning electron microscopy,an X-ray diffraction,an energy dispersed X-ray spectrometer and a photoluminescence spectroscope.The X-ray diffraction spectra were obtained on a Rigaku D/max 2500PC diffractometer.The experimental results reveal that high quality ZnO nanotetrapods can be fabricated on the special parameters,and growth of ZnO nanotetrapods depends on Vapour-Liquid-Solid(VLS) model,and the content of oxygen in the gas,namely,oxygen partial pressure is one of main factors to control morphologies and optical properties of ZnO nanotetrapods;these advantages above are important for realization of optoelectronic devices.

  19. Laser Nanosoldering of Golden and Magnetite Particles and its Possible Application in 3D Printing Devices and Four-Valued Non-Volatile Memories

    Directory of Open Access Journals (Sweden)

    Jaworski Jacek

    2015-12-01

    Full Text Available In recent years the 3D printing methods have been developing rapidly. This article presents researches about a new composite consisted of golden and magnetite nanoparticles which could be used for this technique. Preparation of golden nanoparticles by laser ablation and their soldering by laser green light irradiation proceeded in water environment. Magnetite was obtained on chemical way. During experiments it was tested a change of a size of nanoparticles during laser irradiation, surface plasmon resonance, zeta potential. The obtained golden - magnetite composite material was magnetic after laser irradiation. On the end there was considered the application it for 3D printing devices, water filters and four-valued non-volatile memories.

  20. Evaluation of the use of laser scanning to create key models for 3D printing separate from and augmenting visible light sensing

    Science.gov (United States)

    Straub, Jeremy; Kerlin, Scott

    2016-05-01

    The illicit creation of 3D printed keys is problematic as it can allow intruders nearly undetectable access to secure facilities. Prior work has discussed how keys can be created using visible light sensing. This paper builds on this work by evaluating the utility of keys produced with laser scanning. The quality of the model produced using a structured laser scanning approach is compared to the quality of a model produced using a similarly robust visible light sensing approach.

  1. Creating A 3D urban model by terrestrial laser scanners and photogrammetry techniques: a case study on the historical peninsula of Istanbul

    Science.gov (United States)

    Ergun, Bahadir

    2007-07-01

    Today, terrestrial laser scanning has been a frequently used methodology for the documentation of historical buildings and cultural heritages. The historical peninsula region is the documentation of historical buildings and cover approximately 1500 ha. Terrestrial laser scanning and close range image photogrammetry techniques are integrated to each other to create a 3D urban model of Istanbul including the most important landmarks and the buildings reflecting the most brilliant areas of Byzantine and Ottoman Empires.

  2. A New Approach for Realistic 3D Reconstruction of Planar Surfaces from Laser Scanning Data and Imagery Collected Onboard Modern Low-Cost Aerial Mapping Systems

    Directory of Open Access Journals (Sweden)

    Zahra Lari

    2017-02-01

    Full Text Available Over the past few years, accurate 3D surface reconstruction using remotely-sensed data has been recognized as a prerequisite for different mapping, modelling, and monitoring applications. To fulfill the needs of these applications, necessary data are generally collected using various digital imaging systems. Among them, laser scanners have been acknowledged as a fast, accurate, and flexible technology for the acquisition of high density 3D spatial data. Despite their quick accessibility, the acquired 3D data using these systems does not provide semantic information about the nature of scanned surfaces. Hence, reliable processing techniques are employed to extract the required information for 3D surface reconstruction. Moreover, the extracted information from laser scanning data cannot be effectively utilized due to the lack of descriptive details. In order to provide a more realistic and accurate perception of the scanned scenes using laser scanning systems, a new approach for 3D reconstruction of planar surfaces is introduced in this paper. This approach aims to improve the interpretability of the extracted planar surfaces from laser scanning data using spectral information from overlapping imagery collected onboard modern low-cost aerial mapping systems, which are widely adopted nowadays. In this approach, the scanned planar surfaces using laser scanning systems are initially extracted through a novel segmentation procedure, and then textured using the acquired overlapping imagery. The implemented texturing technique, which intends to overcome the computational inefficiency of the previously-developed 3D reconstruction techniques, is performed in three steps. In the first step, the visibility of the extracted planar surfaces from laser scanning data within the collected images is investigated and a list of appropriate images for texturing each surface is established. Successively, an occlusion detection procedure is carried out to identify the

  3. Flow visualization and 1- and 3-D laser-Doppler-anemometer measurements in models of human carotid arteries.

    Science.gov (United States)

    Liepsch, D; Pflugbeil, G; Matsuo, T; Lesniak, B

    1998-04-01

    Pulsatile flow, wall distensibility, non-Newtonian flow characteristics of blood in flow separation regions, and high/low blood pressure were studied in elastic silicon rubber models having a compliance similar to human vessels and the same surface structure as the biological intima models of (1) a healthy carotid artery model, (2) a 90% stenosis in the ICA, and (3) 80% stenosis in both the internal and external carotid arteries. Flow was visualized for steady flow and pulsatile studies to localize flow separation regions and reattachment points. Local velocity was measured with a 1-, 2-, or 3-D laser-Doppler-anemometer (LDA). Flow in the unstenosed model was Re = 250. In the stenosed models, the Re number decreased to Re = 180 and 213 under the same experimental conditions. High velocity fluctuations with vortices were found in the stenosed models. The jet flow in the stenosis increased up to 4 m/s. With an increasing bifurcation angle, the separation regions in the ECA and ICA increased. Increased flow (Re = 350) led to an increase in flow separation and high velocity shear gradients. The highest shear stresses were nearly 20 times higher than normal. The 90% stenosis created high velocity shear gradients and velocity fluctuations. Downstream of the stenoses, eddies were found over the whole cross-section. In the healthy model a slight flow separation region was observed in the ICA at the branching cross-section whereas in the stenosed models, the flow separation regions extended far into the ICA. We conclude that a detailed understanding of flow is necessary before vascular surgery is performed especially before artificial grafts or patches are implanted.

  4. 3-D laser confocal microscopy study of the oxidation of NdFeB magnets in atmospheric conditions

    Science.gov (United States)

    Meakin, J. P.; Speight, J. D.; Sheridan, R. S.; Bradshaw, A.; Harris, I. R.; Williams, A. J.; Walton, A.

    2016-08-01

    Neodymium iron boron (NdFeB) magnets are used in a number of important applications, such as generators in gearless wind turbines, motors in electric vehicles and electronic goods (e.g.- computer hard disk drives, HDD). Hydrogen can be used as a processing gas to separate and recycle scrap sintered Nd-Fe-B magnets from end-of-life products to form a powder suitable for recycling. However, the magnets are likely to have been exposed to atmospheric conditions prior to processing, and any oxidation could lead to activation problems for the hydrogen decrepitation reaction. Many previous studies on the oxidation of NdFeB magnets have been performed at elevated temperatures; however, few studies have been formed under atmospheric conditions. In this paper a combination of 3-D laser confocal microscopy and Raman spectroscopy have been used to assess the composition, morphology and rate of oxidation/corrosion on scrap sintered NdFeB magnets. Confocal microscopy has been employed to measure the growth of surface reaction products at room temperature, immediately after exposure to air. The results showed that there was a significant height increase at the triple junctions of the Nd-rich grain boundaries. Using Raman spectroscopy, the product was shown to consist of Nd2O3 and formed only on the Nd-rich triple junctions. The diffusion coefficient of the triple junction reaction product growth at 20 °C was determined to be approximately 4 × 10-13 cm2/sec. This value is several orders of magnitude larger than values derived from the diffusion controlled oxide growth observations at elevated temperatures in the literature. This indicates that the growth of the room temperature oxidation products are likely defect enhanced processes at the NdFeB triple junctions.

  5. RECONSTRUCTION, QUANTIFICATION, AND VISUALIZATION OF FOREST CANOPY BASED ON 3D TRIANGULATIONS OF AIRBORNE LASER SCANNING POINT DATA

    Directory of Open Access Journals (Sweden)

    J. Vauhkonen

    2015-03-01

    Full Text Available Reconstruction of three-dimensional (3D forest canopy is described and quantified using airborne laser scanning (ALS data with densities of 0.6–0.8 points m-2 and field measurements aggregated at resolutions of 400–900 m2. The reconstruction was based on computational geometry, topological connectivity, and numerical optimization. More precisely, triangulations and their filtrations, i.e. ordered sets of simplices belonging to the triangulations, based on the point data were analyzed. Triangulating the ALS point data corresponds to subdividing the underlying space of the points into weighted simplicial complexes with weights quantifying the (empty space delimited by the points. Reconstructing the canopy volume populated by biomass will thus likely require filtering to exclude that volume from canopy voids. The approaches applied for this purpose were (i to optimize the degree of filtration with respect to the field measurements, and (ii to predict this degree by means of analyzing the persistent homology of the obtained triangulations, which is applied for the first time for vegetation point clouds. When derived from optimized filtrations, the total tetrahedral volume had a high degree of determination (R2 with the stem volume considered, both alone (R2=0.65 and together with other predictors (R2=0.78. When derived by analyzing the topological persistence of the point data and without any field input, the R2 were lower, but the predictions still showed a correlation with the field-measured stem volumes. Finally, producing realistic visualizations of a forested landscape using the persistent homology approach is demonstrated.

  6. Study on Detection of 3D Laser Scanner Positional Accuracy%三维激光扫描仪点位精度检测研究

    Institute of Scientific and Technical Information of China (English)

    王鸣霄; 戴相喜; 王正强

    2013-01-01

    3D laser scanner is a new fast mean to acquire 3d coordinates of ground objects ,has many increasing in-comparable advantages than traditional measuring means and has wide application prospect .Aim to obtain the actual ac-curacy of its scanning data ,so as to confirm its range of application;this paper designed an experiment ,detection accuracy through surveying the same area using both 3 d laser scanner and total station instrument ,finally get the general accuracy information of 3 d laser scanner ,offer data support to confirm its application range .%三维激光扫描仪扫描作为一种新型的地物三维坐标快速获取手段,具有传统测量手段很多无法比拟的优势,具有广阔的应用前景。为了解其扫描所得点的实际精度,以便确定其适用领域,本文设计实验,采用三维激光扫描仪和全站仪重复测量的方法对其进行检测,得到三维激光扫描仪精度的基本情况,为确定其适用范围提供数据支持。

  7. Laser spectroscopic measurement of isotope shifts of transitions 3d-4p in the ionic spectra of argon, chlorine and sulphur

    Energy Technology Data Exchange (ETDEWEB)

    Eichhorn, A.; Elbel, M.; Kamke, W.; Quad, R.; Bauche, J.

    1982-03-01

    By means of collinear laser spectroscopy at ion beams of Ar/sup +/, S/sup +/ and Cl/sup +/ the isotope shifts of a total of twelve lines could be measured. All the lines are of the type 3psup(n-1)3d..-->..3psup(n-1)4p (3psup(n) being the proper ground configuration of the ions). All the measured shifts are unusually large and prevailingly due to a strong specific mass effect or momentum correlation of the 3d electron with the inner p-shells. The measured shifts could be quantitatively reproduced by computation of the inherent Vinti integrals.

  8. Axial-Stereo 3-D Optical Metrology for Inner Profile of Pipes Using a Scanning Laser Endoscope.

    Science.gov (United States)

    Gong, Yuanzheng; Johnston, Richard S; Melville, C David; Seibel, Eric J

    As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope and axial-stereo vision algorithm. A dense, accurate point cloud of internally machined threads was generated to compare with its corresponding X-ray 3D data as ground truth, and the quantification was analyzed by Iterative Closest Points algorithm.

  9. Uav-Based Acquisition of 3d Point Cloud - a Comparison of a Low-Cost Laser Scanner and Sfm-Tools

    Science.gov (United States)

    Mader, D.; Blaskow, R.; Westfeld, P.; Maas, H.-G.

    2015-08-01

    The Project ADFEX (Adaptive Federative 3D Exploration of Multi Robot System) pursues the goal to develop a time- and cost-efficient system for exploration and monitoring task of unknown areas or buildings. A fleet of unmanned aerial vehicles equipped with appropriate sensors (laser scanner, RGB camera, near infrared camera, thermal camera) were designed and built. A typical operational scenario may include the exploration of the object or area of investigation by an UAV equipped with a laser scanning range finder to generate a rough point cloud in real time to provide an overview of the object on a ground station as well as an obstacle map. The data about the object enables the path planning for the robot fleet. Subsequently, the object will be captured by a RGB camera mounted on the second flying robot for the generation of a dense and accurate 3D point cloud by using of structure from motion techniques. In addition, the detailed image data serves as basis for a visual damage detection on the investigated building. This paper focuses on our experience with use of a low-cost light-weight Hokuyo laser scanner onboard an UAV. The hardware components for laser scanner based 3D point cloud acquisition are discussed, problems are demonstrated and analyzed, and a quantitative analysis of the accuracy potential is shown as well as in comparison with structure from motion-tools presented.

  10. Ship Maintenance Processes with Collaborative Product Lifecycle Management and 3D Terrestrial Laser Scanning Tools: Reducing Costs and Increasing Productivity

    Science.gov (United States)

    2011-04-30

    award; “pushing” potentially high-impact research reports (e.g., via overnight shipping) to selected practitioners and policy-makers; and most...integration of these two technologies within Phase IV of SHIPMAIN could result in substantial cost savings and decreased fleet cycle time via ...original Shipmain plan included: – 3D Terrestr s S ni g echnology ial La er can n T (3D TLS) – Collaborative Product Lifecycle Management (collab

  11. Real-time motion- and B0-correction for LASER-localized spiral-accelerated 3D-MRSI of the brain at 3T.

    Science.gov (United States)

    Bogner, Wolfgang; Hess, Aaron T; Gagoski, Borjan; Tisdall, M Dylan; van der Kouwe, Andre J W; Trattnig, Siegfried; Rosen, Bruce; Andronesi, Ovidiu C

    2014-03-01

    The full potential of magnetic resonance spectroscopic imaging (MRSI) is often limited by localization artifacts, motion-related artifacts, scanner instabilities, and long measurement times. Localized adiabatic selective refocusing (LASER) provides accurate B1-insensitive spatial excitation even at high magnetic fields. Spiral encoding accelerates MRSI acquisition, and thus, enables 3D-coverage without compromising spatial resolution. Real-time position- and shim/frequency-tracking using MR navigators correct motion- and scanner instability-related artifacts. Each of these three advanced MRI techniques provides superior MRSI data compared to commonly used methods. In this work, we integrated in a single pulse sequence these three promising approaches. Real-time correction of motion, shim, and frequency-drifts using volumetric dual-contrast echo planar imaging-based navigators were implemented in an MRSI sequence that uses low-power gradient modulated short-echo time LASER localization and time efficient spiral readouts, in order to provide fast and robust 3D-MRSI in the human brain at 3T. The proposed sequence was demonstrated to be insensitive to motion- and scanner drift-related degradations of MRSI data in both phantoms and volunteers. Motion and scanner drift artifacts were eliminated and excellent spectral quality was recovered in the presence of strong movement. Our results confirm the expected benefits of combining a spiral 3D-LASER-MRSI sequence with real-time correction. The new sequence provides accurate, fast, and robust 3D metabolic imaging of the human brain at 3T. This will further facilitate the use of 3D-MRSI for neuroscience and clinical applications.

  12. Repumping and spectroscopy of laser-cooled Sr atoms using the (5s5p)3P2-(5s4d)3D2 transition

    Science.gov (United States)

    Mickelson, P. G.; Martinez de Escobar, Y. N.; Anzel, P.; De Salvo, B. J.; Nagel, S. B.; Traverso, A. J.; Yan, M.; Killian, T. C.

    2009-12-01

    We describe repumping and spectroscopy of laser-cooled strontium (Sr) atoms using the (5s5p)3P2-(5s4d)3D2 transition. Atom number in a magneto-optical trap is enhanced by driving this transition because Sr atoms that have decayed into the (5s5p)3P2 dark state are repumped back into the (5s2)1S0 ground state. Spectroscopy of 84Sr, 86Sr, 87Sr and 88Sr improves the value of the (5s5p)3P2-(5s4d)3D2 transition frequency and determines the isotope shifts for the transition accurately enough to guide laser-cooling experiments with less abundant isotopes.

  13. Make or Buy: Cost Impacts of Additive Manufacturing, 3D Laser Scanning Technology, and Collaborative Product Lifecycle Management on Ship Maintenance and Modernization

    Science.gov (United States)

    2015-05-01

    1 Make or Buy: Cost Impacts of Additive Manufacturing, 3D Laser Scanning Technology, and Collaborative Product Lifecycle Management on Ship...and Collaborative Product Lifecycle Management on Ship Maintenance and Modernization 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER...plants 3 Potential Technology 2: Collaborative Product Lifecycle Management • To “integrate people, processes, and information” • Electronically

  14. 3D laser scanner application in topographic survey%三维激光扫描仪在地形测量中的应用

    Institute of Scientific and Technical Information of China (English)

    李子坡; 李晓静

    2013-01-01

    三维激光扫描仪与全球定位系统(GPS)的结合是数字测图的又一次创新和进步,其具有简捷、高效、高清晰的数据获取能力,与传统测绘相比具有劳动强度低、时间短、测图的灵活性强,智能化、兼容性强等优势。本文介绍了三维激光扫描仪应用的现状,并与传统数据采集方式进行了比较,并结合实例将三维激光扫描技术应用于大比例尺地形测量中,结果表明了三维激光扫描技术方案能够很好的取代传统测量方式,保证测绘数据质量,能够提高作业效率。%The 3D laser scanner and a global positioning system (GPS) is combined with another innovation and progress in digital mapping, which is a simple, efficient, high resolution data acquisition capacity, compared with the traditional mapping has the advantages of low labor intensity, time is short, mapping flexibility, intelligent, strong compatibility and other advantages. This paper introduces the present situation of the application of 3D laser scanner, and compared with the traditional data acquisition methods, combined with the example, the application of 3D laser scanning technology in large scale topographic survey, results show that the 3D laser scanning technology to replace the traditional measurement methods are good, ensure the quality of Surveying and mapping data, can improve the efficiency of.

  15. The Influence of Process Parameters on the Surface Roughness of a 3D-Printed Co–Cr Dental Alloy Produced via Selective Laser Melting

    Directory of Open Access Journals (Sweden)

    Min-Ho Hong

    2016-12-01

    Full Text Available Selective laser melting (SLM, used to fabricate metallic objects with high geometrical complexity, is currently of increasing interest to the fields of medicine and dentistry. SLM-fabricated products should have highly smooth surfaces to minimize the use of post-processing procedures such as finishing and polishing. This study investigated the effect of various laser process parameters (laser power, scan rate, and scan-line spacing on the surface roughness of a Co–Cr dental alloy that was three-dimensionally (3D constructed via SLM. Initially, a single-line formation test was used to determine the optimal laser power (200 W and scan rate (128.6 mm/s that resulted in beads with an optimal profile. During subsequent multi-layer formation tests, the 3D Co–Cr body with the smoothest surface was produced using a scan-line spacing of 100 μm. The findings of this study show that laser process parameters have crucial effects on the surface quality of SLM-fabricated Co–Cr dental alloys.

  16. 三维激光扫描仪精度测试及应用%Accuracy testing and application of 3D laser scanner

    Institute of Scientific and Technical Information of China (English)

    张铁军; 沈家海; 申文永

    2015-01-01

    The basic principle of 3D laser scanner, and the test methods of its positional accuracy in pile surveying were introduced in this paper. According to engineering requirements, we arranged control points, chose columns under the viaduct in land as observation target, measured the center coordinates respectively using 3D laser scanner and total station, analyzed the measuring accuracy of 3D laser scanner based on total station measuring results, and explored its application in engineering surveying.%介绍了三维激光扫描仪的基本原理及其应用于桩基测量精度分析的测试方法。按照工程需求,布置控制点,选择陆地高架桥下的圆柱作为观测目标,分别用三维激光扫描仪和全站仪测量出圆心坐标,以全站仪测量成果为基准,分析三维激光扫描仪的测量精度,探索其在工程测量中的应用。

  17. 三维激光扫描技术在数字城市中的应用%Application of 3D Laser Scanning Technology to Digital City

    Institute of Scientific and Technical Information of China (English)

    李杰; 周兴华; 唐秋华; 李君益; 厉峰

    2011-01-01

    三维激光扫描技术具有精度高、速度快、真实感强、数据量大、作业安全等众多优点,应用领域日益广泛。通过三维激光扫描仪对建筑物进行扫描作业和数据处理,建立建筑物的三维模型,并以Leica的ScanStation2地面三维激光扫描仪为例,讨论激光扫描仪在数字城市中的应用。%The 3D laser scanning technology has become widely used in various fields for its advantages such as high precision,high speed,better truthfulness,huge data volume and its safty assurance in application.In this paper,the scanning of buildings and data processing are carried out to establish the 3D models for the buildings.Then Leica-ScanStation2 3D laser scanner is taken as an example to discuss the application of laser scanners to the digital city construction.

  18. Large-scale 3D laser scanning techniques and their applications%大尺度3D激光扫描技术及其应用

    Institute of Scientific and Technical Information of China (English)

    封全宏; 魏彪; 崔大庆

    2004-01-01

    针对大物体3D原型及测量的3D激光扫描技术近年来得到了飞速的发展.与其他3D测量技术相比,大尺度3D激光扫描技术可以在中、大距离内快速捕获大物体全区域的数字原型,特别是考虑时间和成本,大尺度3D激光扫描技术在不同环境和地点中捕获复杂物体的3D数据是十分奏效的.在详细介绍大尺度3D激光扫描技术原理的基础上,给出了在建筑结构、隧道工程等方面的一些应用实例.实际应用结果表明,大尺度3D激光扫描技术是各种反求工程对称应用的一种独特的工具或方法.%3D laser scanning techniques are in a great development recent years for the 3D measuring and modeling of large objects. Comparing to other 3D measuring techniques, a large-scale 3D scanner can quickly capture a full-coverage digital model of a large object within a range of the middle to large distances. Especially, it is quite effective, in respect to both time and cost, to apply such techniques to capture 3D digital data of complicated objects in different environments and situations. In this paper, the large-scale 3D laser scanning techniques are introduced, and some application examples in 3D modeling in reverse engineering, 3D mapping and documentation for architecture and tunneling, are presented.

  19. 3D Elevation Program—Virtual USA in 3D

    Science.gov (United States)

    Lukas, Vicki; Stoker, J.M.

    2016-04-14

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  20. Laser 3D printing with sub-microscale resolution of porous elastomeric scaffolds for supporting human bone stem cells.

    Science.gov (United States)

    Petrochenko, Peter E; Torgersen, Jan; Gruber, Peter; Hicks, Lucas A; Zheng, Jiwen; Kumar, Girish; Narayan, Roger J; Goering, Peter L; Liska, Robert; Stampfl, Jürgen; Ovsianikov, Aleksandr

    2015-04-01

    A reproducible method is needed to fabricate 3D scaffold constructs that results in periodic and uniform structures with precise control at sub-micrometer and micrometer length scales. In this study, fabrication of scaffolds by two-photon polymerization (2PP) of a biodegradable urethane and acrylate-based photoelastomer is demonstrated. This material supports 2PP processing with sub-micrometer spatial resolution. The high photoreactivity of the biophotoelastomer permits 2PP processing at a scanning speed of 1000 mm s(-1), facilitating rapid fabrication of relatively large structures (>5 mm(3)). These structures are custom printed for in vitro assay screening in 96-well plates and are sufficiently flexible to enable facile handling and transplantation. These results indicate that stable scaffolds with porosities of greater than 60% can be produced using 2PP. Human bone marrow stromal cells grown on 3D scaffolds exhibit increased growth and proliferation compared to smooth 2D scaffold controls. 3D scaffolds adsorb larger amounts of protein than smooth 2D scaffolds due to their larger surface area; the scaffolds also allow cells to attach in multiple planes and to completely infiltrate the porous scaffolds. The flexible photoelastomer material is biocompatible in vitro and is associated with facile handling, making it a viable candidate for further study of complex 3D-printed scaffolds.

  1. Initial progress in the recording of crime scene simulations using 3D laser structured light imagery techniques for law enforcement and forensic applications

    Science.gov (United States)

    Altschuler, Bruce R.; Monson, Keith L.

    1998-03-01

    Representation of crime scenes as virtual reality 3D computer displays promises to become a useful and important tool for law enforcement evaluation and analysis, forensic identification and pathological study and archival presentation during court proceedings. Use of these methods for assessment of evidentiary materials demands complete accuracy of reproduction of the original scene, both in data collection and in its eventual virtual reality representation. The recording of spatially accurate information as soon as possible after first arrival of law enforcement personnel is advantageous for unstable or hazardous crime scenes and reduces the possibility that either inadvertent measurement error or deliberate falsification may occur or be alleged concerning processing of a scene. Detailed measurements and multimedia archiving of critical surface topographical details in a calibrated, uniform, consistent and standardized quantitative 3D coordinate method are needed. These methods would afford professional personnel in initial contact with a crime scene the means for remote, non-contacting, immediate, thorough and unequivocal documentation of the contents of the scene. Measurements of the relative and absolute global positions of object sand victims, and their dispositions within the scene before their relocation and detailed examination, could be made. Resolution must be sufficient to map both small and large objects. Equipment must be able to map regions at varied resolution as collected from different perspectives. Progress is presented in devising methods for collecting and archiving 3D spatial numerical data from crime scenes, sufficient for law enforcement needs, by remote laser structured light and video imagery. Two types of simulation studies were done. One study evaluated the potential of 3D topographic mapping and 3D telepresence using a robotic platform for explosive ordnance disassembly. The second study involved using the laser mapping system on a

  2. Analysis of Spot Error Sources of 3D Laser Scanning%三维激光扫描点位误差源分析

    Institute of Scientific and Technical Information of China (English)

    王林

    2014-01-01

    目前对三维激光扫描的分析主要停留在误差模型的建立上,没有对三维激光扫描仪的特点及其所受的误差进行分析,而三维激光扫描仪的系统误差和偶然误差都将会对整个误差模型的建立产生影响,点位误差源的准确分析是点位准确建立点位误差模型的基础。基于此,本文对三维激光扫描仪的点位误差源进行了分析,得到了不同误差源的误差模型,并给出了不同条件可能对激光扫描仪误差影响的大小。%At present, the analysis of 3D laser scanning mainly stays in the construction of error model, but not on the characteristics of 3D laser scanner and its error analysis. The system error and random error can even affect the con-struction of the entire error model. The accurate analysis of the spot error sources is the basis to establish an accurate spot error model. On this basis, this article analyzes the spot error sources of 3D laser scanner, obtains the error model of different error sources and gives the size of the influence of the laser scanner under different conditions.

  3. An Area Inequality for Ellipses Inscribed in Quadrilaterals

    CERN Document Server

    Horwitz, Alan

    2009-01-01

    If E is any ellipse inscribed in a convex quadrilateral, D, then we prove that Area(E)/Area(D) is less than or equal to pi/4, and equality holds if and only if D is a parallelogram and E is tangent to the sides of D at the midpoints. This extends well known results for ellipses inscribed in triangles. We also prove that the foci of the unique ellipse of maximal area inscribed in a parallelogram, D, lie on the orthogonal least squares line for the vertices of D. This does not hold in general for convex quadrilaterals.

  4. Surgical planning for resection of an ameloblastoma and reconstruction of the mandible using a selective laser sintering 3D biomodel.

    Science.gov (United States)

    Sannomiya, Eduardo Kazuo; Silva, Jorge Vicente L; Brito, Antonio Albuquerque; Saez, Daniel Martinez; Angelieri, Fernanda; Dalben, Gisele da Silva

    2008-07-01

    Ameloblastoma is a benign locally aggressive infiltrative odontogenic lesion. It is characterized by slow growth and painless swelling. The treatment for ameloblastoma varies from curettage to en bloc resection, and the reported recurrence rates after treatment are high; the safety margin of resection is important to avoid recurrence. Advances in technology brought about great benefits in dentistry; a new generation of computed tomography scanners and 3-dimensional images enhance the surgical planning and management of maxillofacial tumors. The development of new prototyping systems provides accurate 3D biomodels on which surgery can be simulated, especially in cases of ameloblastoma, in which the safety margin is important for treatment success. A case of mandibular follicular ameloblastoma is reported where a 3D biomodel was used before and during surgery.

  5. Laser-Deposited In Situ TiC-Reinforced Nickel Matrix Composites: 3D Microstructure and Tribological Properties (Postprint)

    Science.gov (United States)

    2014-04-03

    was measured using a stan- dard Vickers microhardness tester using a 300-g load. Sliding friction and wear testing was con- ducted with a Falex (Implant...exported to AvizoFire 6.3 format for 3D visualization of TiC and graphite reinforcements. Microhardness and Tribological Properties The microhardness ...Sciences) ISC-200 pin- on-disk (POD) system at room temperature. The samples were openly exposed in lab air (40% RH) during the tests . Tests were

  6. Discovering new methods of data fusion, visualization, and analysis in 3D immersive environments for hyperspectral and laser altimetry data

    Science.gov (United States)

    Moore, C. A.; Gertman, V.; Olsoy, P.; Mitchell, J.; Glenn, N. F.; Joshi, A.; Norpchen, D.; Shrestha, R.; Pernice, M.; Spaete, L.; Grover, S.; Whiting, E.; Lee, R.

    2011-12-01

    Immersive virtual reality environments such as the IQ-Station or CAVE° (Cave Automated Virtual Environment) offer new and exciting ways to visualize and explore scientific data and are powerful research and educational tools. Combining remote sensing data from a range of sensor platforms in immersive 3D environments can enhance the spectral, textural, spatial, and temporal attributes of the data, which enables scientists to interact and analyze the data in ways never before possible. Visualization and analysis of large remote sensing datasets in immersive environments requires software customization for integrating LiDAR point cloud data with hyperspectral raster imagery, the generation of quantitative tools for multidimensional analysis, and the development of methods to capture 3D visualizations for stereographic playback. This study uses hyperspectral and LiDAR data acquired over the China Hat geologic study area near Soda Springs, Idaho, USA. The data are fused into a 3D image cube for interactive data exploration and several methods of recording and playback are investigated that include: 1) creating and implementing a Virtual Reality User Interface (VRUI) patch configuration file to enable recording and playback of VRUI interactive sessions within the CAVE and 2) using the LiDAR and hyperspectral remote sensing data and GIS data to create an ArcScene 3D animated flyover, where left- and right-eye visuals are captured from two independent monitors for playback in a stereoscopic player. These visualizations can be used as outreach tools to demonstrate how integrated data and geotechnology techniques can help scientists see, explore, and more adequately comprehend scientific phenomena, both real and abstract.

  7. Assessment of statistical agreement of three techniques for the study of cut marks: 3D digital microscope, laser scanning confocal microscopy and micro-photogrammetry.

    Science.gov (United States)

    Maté-González, Miguel Ángel; Aramendi, Julia; Yravedra, José; Blasco, Ruth; Rosell, Jordi; González-Aguilera, Diego; Domínguez-Rodrigo, Manuel

    2017-09-01

    In the last few years, the study of cut marks on bone surfaces has become fundamental for the interpretation of prehistoric butchery practices. Due to the difficulties in the correct identification of cut marks, many criteria for their description and classification have been suggested. Different techniques, such as three-dimensional digital microscope (3D DM), laser scanning confocal microscopy (LSCM) and micro-photogrammetry (M-PG) have been recently applied to the study of cut marks. Although the 3D DM and LSCM microscopic techniques are the most commonly used for the 3D identification of cut marks, M-PG has also proved to be very efficient and a low-cost method. M-PG is a noninvasive technique that allows the study of the cortical surface without any previous preparation of the samples, and that generates high-resolution models. Despite the current application of microscopic and micro-photogrammetric techniques to taphonomy, their reliability has never been tested. In this paper, we compare 3D DM, LSCM and M-PG in order to assess their resolution and results. In this study, we analyse 26 experimental cut marks generated with a metal knife. The quantitative and qualitative information registered is analysed by means of standard multivariate statistics and geometric morphometrics to assess the similarities and differences obtained with the different methodologies. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  8. A Robotic Indoor 3D Mapping System Using a 2D Laser Range Finder Mounted on a Rotating Four-Bar Linkage of a Mobile Platform

    Directory of Open Access Journals (Sweden)

    Yu-Shin Chou

    2013-01-01

    Full Text Available This paper describes our work in developing a 3D robotic mapping system composed by an experimental mobile platform equipped with a rotating laser range finder (LRF. For the purpose of obtaining more complete 3D scans of the environment, we design, construct and calibrate a crank‐rocker four‐bar linkage so that a LRF mounted on it could undergo repetitive rotational motion between two extreme positions, allowing both horizontal and vertical scans. To reduce the complexity of map representation suitable for optimization later, the local map from the LRF is a grid map represented by a distance‐transformed (DT matrix. We compare the DT‐transformed maps and find the transformation matrix of a robot pose by a linear simplex‐based map optimization method restricted to a local region allows efficient alignment of maps in scan matching. Several indoor 2D and 3D mapping experiments are presented to demonstrate the consistency, efficiency and accuracy of the 3D mapping system for a mobile robot that is stationary or in motion.

  9. Numerical Simulation and Analysis on 3D Temperature Field of the Metal Ablated with Femtosecond Pulse Laser

    Energy Technology Data Exchange (ETDEWEB)

    Yang Li; Yang Wei [Science College, Civil Aviation University of China, Tianjin 300300 (China); Wang Chingyue, E-mail: y_lyang@yahoo.com.cn [Key Laboratory of Opto-electronic Information Science and Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China)

    2011-02-01

    To describe femtosecond laser ablation on the metal, numerical simulation on the basis of the double-temperature equation for three-dimension temperature field of the copper ablated with femtosecond pulse laser was performed by finite-difference method. Based on imbalance of the electronic and lattice's temperatures, the calefactive process of the electron and the lattice was obtained, respectively. The dependence of the electron-lattice coupling time on irradiated laser fluence was studied. The ablation depth and the ablation radius of the copper for single pulse fluence were calculated. The dependence of the start ablation (phase explosion arises) time of the copper on irradiated laser fluence was studied. The results indicate that the material jet due to phase explosion is earlier and the duration of ablation is longer with the increase of the laser fluence. When the laser fluence is higher than 1.5 J/cm{sup 2} the ablation start time is about 2-3 ps.

  10. Accurate assessment of breast volume: a study comparing the volumetric gold standard (direct water displacement measurement of mastectomy specimen) with a 3D laser scanning technique.

    Science.gov (United States)

    Yip, Jia Miin; Mouratova, Naila; Jeffery, Rebecca M; Veitch, Daisy E; Woodman, Richard J; Dean, Nicola R

    2012-02-01

    Preoperative assessment of breast volume could contribute significantly to the planning of breast-related procedures. The availability of 3D scanning technology provides us with an innovative method for doing this. We performed this study to compare measurements by this technology with breast volume measurement by water displacement. A total of 30 patients undergoing 39 mastectomies were recruited from our center. The volume of each patient's breast(s) was determined with a preoperative 3D laser scan. The volume of the mastectomy specimen was then measured in the operating theater by water displacement. There was a strong linear association between breast volumes measured using the 2 different methods when using a Pearson correlation (r = 0.95, P Scanner as a tool for assessment of breast volume.

  11. High-resolution 3-D mapping using terrestrial laser scanning as a tool for geomorphological and speleogenetical studies in caves: An example from the Lessini mountains (North Italy)

    Science.gov (United States)

    Fabbri, Stefano; Sauro, Francesco; Santagata, Tommaso; Rossi, Guido; De Waele, Jo

    2017-03-01

    Terrestrial laser scanning (TLS) is increasingly used in geomorphology for the study of medium- to small scale landforms. A light weight, compact and portable TLS device has been used in the Grotta A Cave (Mt. Lessini, N Italy) to make a detailed 3D model of the underground environment. A total of 16 scans were used to survey the about 150 m long cave in < 6 h. The 3D model of the cave walls makes it possible to carry out morphometric measurements on the different cave environments. The TLS data allowed us to calculate cave volumes and distinguish cupola, phreatic conduit and basalt dike volumes. Wall roughness analysis also allowed recognising smaller-scale morphologies such as megascallops, differential corrosion forms and mineral crusts. These observations have enabled us to discern between different karstification processes and speleogenetic phases, highlighting the importance of condensation-corrosion on the cave passage enlargement in a quantitative way.

  12. Mechanical properties and microstructure of 3D-printed high Co-Ni secondary hardening steel fabricated by laser melting deposition

    Science.gov (United States)

    Duan, Hui-ping; Liu, Xiao; Ran, Xian-zhe; Li, Jia; Liu, Dong

    2017-09-01

    The mechanical properties and microstructure of the 3D-printed high Co-Ni secondary hardening steel fabricated by the laser melting deposition technique was investigated using a material testing machine and electron microscopy. A microstructure investigation revealed that the samples consist of martensite laths, fine dispersed precipitates, and reverted austenite films at the martensite lath boundaries. The precipitates are enriched with Co and Mo. Because the sample tempered at 486°C has smaller precipitates and a higher number of precipitates per unit area, it exhibits better mechanical properties than the sample tempered at 498°C. Although the 3D-printed samples have the same phase constituents as AerMet 100 steel, the mechanical properties are slightly worse than those of the commercial wrought AerMet 100 steel because of the presence of voids.

  13. Repumping and spectroscopy of laser-cooled Sr atoms using the (5s5p)3P2 - (5s4d)3D2 transition

    CERN Document Server

    Mickelson, P G; Anzel, P; DeSalvo, B J; Nagel, S B; Traverso, A J; Yan, M; Killian, T C

    2009-01-01

    We describe repumping and spectroscopy of laser-cooled strontium (Sr) atoms using the (5s5p)3P2 - (5s4d)3D2 transition. Atom number in a magneto-optical trap is enhanced by driving this transition because Sr atoms that have decayed into the (5s5p)3P2 dark state are repumped back into the (5s2)1S0 ground state. Spectroscopy of 84Sr, 86Sr, 87Sr, and 88Sr improves the value of the (5s5p)3P2 - (5s4d)3D2 transition frequency for 88Sr and determines the isotope shifts for the transition.

  14. Color 3D Reverse Engineering

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper presents a principle and a method of col or 3D laser scanning measurement. Based on the fundamental monochrome 3D measureme nt study, color information capture, color texture mapping, coordinate computati on and other techniques are performed to achieve color 3D measurement. The syste m is designed and composed of a line laser light emitter, one color CCD camera, a motor-driven rotary filter, a circuit card and a computer. Two steps in captu ring object's images in the measurement process: Firs...

  15. Performance assessment of simulated 3D laser images using Geiger-mode avalanche photo-diode: tests on simple synthetic scenarios

    Science.gov (United States)

    Coyac, Antoine; Hespel, Laurent; Riviere, Nicolas; Briottet, Xavier

    2015-10-01

    In the past few decades, laser imaging has demonstrated its potential in delivering accurate range images of objects or scenes, even at long range or under bad weather conditions (rain, fog, day and night vision). We note great improvements in the conception and development of single and multi infrared sensors, concerning embedability, circuitry reading capacity, or pixel resolution and sensitivity, allowing a wide diversity of applications (i.e. enhanced vision, long distance target detection and reconnaissance, 3D DSM generation). Unfortunately, it is often difficult to dispose of all the instruments to compare their performance for a given application. Laser imaging simulation has shown to be an interesting alternative to acquire real data, offering a higher flexibility to perform this sensors comparison, plus being time and cost efficient. In this paper, we present a 3D laser imaging end-to-end simulator using a focal plane array with Geiger mode detection, named LANGDOC. This work aims to highlight the interest and capability of this new generation of photo-diodes arrays, especially for airborne mapping and surveillance of high risk areas.

  16. Accuracy of 3D cartilage models generated from MR images is dependent on cartilage thickness: laser scanner based validation of in vivo cartilage.

    Science.gov (United States)

    Koo, Seungbum; Giori, Nicholas J; Gold, Garry E; Dyrby, Chris O; Andriacchi, Thomas P

    2009-12-01

    Cartilage morphology change is an important biomarker for the progression of osteoarthritis. The purpose of this study was to assess the accuracy of in vivo cartilage thickness measurements from MR image-based 3D cartilage models using a laser scanning method and to test if the accuracy changes with cartilage thickness. Three-dimensional tibial cartilage models were created from MR images (in-plane resolution of 0.55 mm and thickness of 1.5 mm) of osteoarthritic knees of ten patients prior to total knee replacement surgery using a semi-automated B-spline segmentation algorithm. Following surgery, the resected tibial plateaus were laser scanned and made into 3D models. The MR image and laser-scan based models were registered to each other using a shape matching technique. The thicknesses were compared point wise for the overall surface. The linear mixed-effects model was used for statistical test. On average, taking account of individual variations, the thickness measurements in MRI were overestimated in thinner (<2.5 mm) regions. The cartilage thicker than 2.5 mm was accurately predicted in MRI, though the thick cartilage in the central regions was underestimated. The accuracy of thickness measurements in the MRI-derived cartilage models systemically varied according to native cartilage thickness.

  17. 基于激光扫描技术的三维模型重建%3D Model Reconstruction Based on Laser Scanning Technique

    Institute of Scientific and Technical Information of China (English)

    Nguyen Tien Thanh; 刘修国; 王红平; 于明旭; 周文浩

    2011-01-01

    通过分析三维激光扫描系统获取的点云数据,得到了利用点云数据构建三维模型的技术、方法和流程.介绍了利用地面三维激光扫描仪获取点云数据的过程以及结合RiSCAN PRO软件和Geomagic Studio软件进行建模的方法.对原始测量的点云数据进行处理(去除噪声,平滑,对多站点数据做拼接配准,提取目标建筑物等)得到正确和完整的目标建筑物的表面信息,然后构建三角网建立它的三维表面模型,最后通过所拍的照片进行纹理映射得到真实的三维模型.实验结果表明,利用上述方法可以有效地处理三维激光扫描获取的点云数据,实现对建筑物快速三维可视化建模.%The technique, method and workflow of building 3D model through the use of 3D laser scanning system to acquire point cloud data are presented. The point cloud data acquirement process and the combination of RiSCAN PRO software and Geomagic Studio software to build 3D model are discussed. The original measurement data (noise elimination, smoothing, data registration, target object extraction and so on) are processed to get the exact and full facet information of the target, and then a triangular mesh model is built for the target. Finally, through texture mapping done by using photos taken in the data acquirement process, the real 3D model of the target object is got. The experiment shows that the point cloud acquired by 3D laser scanning system can be effectively dealt with and the 3D model can be achieved via the technique mentioned above.

  18. 3D point cloud data from laser scanning along the 2014 South Napa Earthquake surface rupture, California, USA

    Science.gov (United States)

    DeLong, Stephen B.

    2016-01-01

    Point cloud data collected along a 500 meter portion of the 2014 South Napa Earthquake surface rupture near Cuttings Wharf Road, Napa, CA, USA. The data include 7 point cloud files (.laz). The files are named with the location and date of collection and either ALSM for airborne laser scanner data or TLS for terrestrial laser scanner data. The ALSM data re previously released but are included here because they have been precisely aligned with the TLS data as described in the processing section of this metadata. 

  19. Prediction of the hardness profile of an AISI 4340 steel cylinder heat-treated by laser - 3D and artificial neural networks modelling and experimental validation

    Energy Technology Data Exchange (ETDEWEB)

    Hadhri, Mahdi; Ouafi, Abderazzak El; Barka, Noureddine [University of Quebec, Rimouski (Canada)

    2017-02-15

    This paper presents a comprehensive approach developed to design an effective prediction model for hardness profile in laser surface transformation hardening process. Based on finite element method and Artificial neural networks, the proposed approach is built progressively by (i) examining the laser hardening parameters and conditions known to have an influence on the hardened surface attributes through a structured experimental investigation, (ii) investigating the laser hardening parameters effects on the hardness profile through extensive 3D modeling and simulation efforts and (ii) integrating the hardening process parameters via neural network model for hardness profile prediction. The experimental validation conducted on AISI4340 steel using a commercial 3 kW Nd:Yag laser, confirm the feasibility and efficiency of the proposed approach leading to an accurate and reliable hardness profile prediction model. With a maximum relative error of about 10 % under various practical conditions, the predictive model can be considered as effective especially in the case of a relatively complex system such as laser surface transformation hardening process.

  20. Pulsed laser deposition-assisted synthesis of porous WP2 nanosheet arrays integrated on graphite paper as a 3D flexible cathode for efficient hydrogen evolution

    Science.gov (United States)

    Pi, Mingyu; Guo, Weimeng; Wu, Tianli; Wang, Xiaodeng; Zhang, Dingke; Wang, Shuxia; Chen, Shijian

    2017-10-01

    Herein, porous WP2 nanosheet arrays integrated on graphite paper (P-WP2 NSs/GP) as 3D flexible cathode for electrocatalytic hydrogen evolution reaction (HER) are prepared by in situ phosphidation via vacuum encapsulation assisted by pulsed laser deposition technique. Compared to the electrode without pre-deposition process, the enhanced catalytic activities are attributed to the increased effective catalyst loading and the reinforced charge transport kinetics. The results make the present P-WP2 NSs/GP as a promising cathode for energy conversion and paves a new way for designing and fabricating efficient electrodes toward HER.

  1. A Comprehensive Automated 3D Approach for Building Extraction, Reconstruction, and Regularization from Airborne Laser Scanning Point Clouds

    Directory of Open Access Journals (Sweden)

    Norbert Pfeifer

    2008-11-01

    Full Text Available Three dimensional city models are necessary for supporting numerous management applications. For the determination of city models for visualization purposes, several standardized workflows do exist. They are either based on photogrammetry or on LiDAR or on a combination of both data acquisition techniques. However, the automated determination of reliable and highly accurate city models is still a challenging task, requiring a workflow comprising several processing steps. The most relevant are building detection, building outline generation, building modeling, and finally, building quality analysis. Commercial software tools for building modeling require, generally, a high degree of human interaction and most automated approaches described in literature stress the steps of such a workflow individually. In this article, we propose a comprehensive approach for automated determination of 3D city models from airborne acquired point cloud data. It is based on the assumption that individual buildings can be modeled properly by a composition of a set of planar faces. Hence, it is based on a reliable 3D segmentation algorithm, detecting planar faces in a point cloud. This segmentation is of crucial importance for the outline detection and for the modeling approach. We describe the theoretical background, the segmentation algorithm, the outline detection, and the modeling approach, and we present and discuss several actual projects.

  2. A Comprehensive Automated 3D Approach for Building Extraction, Reconstruction, and Regularization from Airborne Laser Scanning Point Clouds.

    Science.gov (United States)

    Dorninger, Peter; Pfeifer, Norbert

    2008-11-17

    Three dimensional city models are necessary for supporting numerous management applications. For the determination of city models for visualization purposes, several standardized workflows do exist. They are either based on photogrammetry or on LiDAR or on a combination of both data acquisition techniques. However, the automated determination of reliable and highly accurate city models is still a challenging task, requiring a workflow comprising several processing steps. The most relevant are building detection, building outline generation, building modeling, and finally, building quality analysis. Commercial software tools for building modeling require, generally, a high degree of human interaction and most automated approaches described in literature stress the steps of such a workflow individually. In this article, we propose a comprehensive approach for automated determination of 3D city models from airborne acquired point cloud data. It is based on the assumption that individual buildings can be modeled properly by a composition of a set of planar faces. Hence, it is based on a reliable 3D segmentation algorithm, detecting planar faces in a point cloud. This segmentation is of crucial importance for the outline detection and for the modeling approach. We describe the theoretical background, the segmentation algorithm, the outline detection, and the modeling approach, and we present and discuss several actual projects.

  3. A multinational deployment of 3D laser scanning to study craniofacial dysmorphology in fetal alcohol spectrum disorders

    Science.gov (United States)

    Rogers, Jeff; Wernert, Eric; Moore, Elizabeth; Ward, Richard; Wetherill, Leah F.; Foroud, Tatiana

    2007-01-01

    Craniofacial anthropometry (the measurement and analysis of head and face dimensions) has been used to assess and describe abnormal craniofacial variation (dysmorphology) and the facial phenotype in many medical syndromes. Traditionally, anthropometry measurements have been collected by the direct application of calipers and tape measures to the subject's head and face, and can suffer from inaccuracies due to restless subjects, erroneous landmark identification, clinician variability, and other forms of human error. Three-dimensional imaging technologies promise a more effective alternative that separates the acquisition and measurement phases to reduce these variabilities while also enabling novel measurements and longitudinal analysis of subjects. Indiana University (IU) is part of an international consortium of researchers studying fetal alcohol spectrum disorders (FASD). Fetal alcohol exposure results in predictable craniofacial dysmorphologies, and anthropometry has been proven to be an effective diagnosis tool for the condition. IU is leading a project to study the use of 3D surface scanning to acquire anthropometry data in order to more accurately diagnose FASD, especially in its milder forms. This paper describes our experiences in selecting, verifying, supporting, and coordinating a set of 3D scanning systems for use in collecting facial scans and anthropometric data from around the world.

  4. 地面三维激光扫描仪的测量误差分析%The Measurement Error Analysis of a Terrestrial 3D Laser Scanner

    Institute of Scientific and Technical Information of China (English)

    杨忞婧

    2013-01-01

    The appearance of 3D laser scanning technology provide a new technical support for obtaining 3D spatial information rapidly,effectively and accurately.3D laser scanner will not be restricted by the day and night,it can work all the day and obtain high precision 3d information and reflectivity information of points on the surface,and realize quickly 3d reconstruction of objects.But,because of instruments'own technological limitations and the influence from and the environment,the accuracy of the field collected point cloud data will be influent on different levels,and make the point cloud data processing will be complicated and slow,even the final 3d model will be not accord with the real objects.This article mainly aims at analyzing distance and angle measurement errors of the terrestrial 3D laser scanner,and the origin of the errors and form a point error model,it provides a necessary condition for improving the speed and precision of 3D point cloud data processing.%三维激光扫描技术的出现为快速、有效、准确获取三维空间信息提供了全新的技术支持.三维激光扫描仪能够不受白天黑夜的限制,全天侯对任意物体进行扫描并获取高精度的物体表面点的三维信息及反射率信息,从而快速实现物体的三维重建.然而,由于在应用过程中,受到仪器本身技术的限制以及外界的影响,使得外业采集的点云数据的精度受到不同程度的影响,从而使得后续的点云数据处理变得复杂且缓慢,甚至使得最终生成的三维模型与实际物体不一致.主要针对地面三维激光扫描仪在测量过程中存在的测距误差、测角误差以及误差来源进行了详细地分析并构建了点位误差模型,为提高三维激光点云数据处理的效率和精度提供了必要的条件.

  5. Evaluation of the Convergence Region of an Automated Registration Method for 3D Laser Scanner Point Clouds.

    Science.gov (United States)

    Bae, Kwang-Ho

    2009-01-01

    Using three dimensional point clouds from both simulated and real datasets from close and terrestrial laser scanners, the rotational and translational convergence regions of Geometric Primitive Iterative Closest Points (GP-ICP) are empirically evaluated. The results demonstrate the GP-ICP has a larger rotational convergence region than the existing methods, e.g., the Iterative Closest Point (ICP).

  6. Adhesion property and high-temperature oxidation behavior of Cr-coated Zircaloy-4 cladding tube prepared by 3D laser coating

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Gil, E-mail: hgkim@kaeri.re.kr; Kim, Il-Hyun; Jung, Yang-Il; Park, Dong-Jun; Park, Jeong-Yong; Koo, Yang-Hyun

    2015-10-15

    A 3D laser coating technology using Cr powder was developed for Zr-based alloys considering parameters such as: the laser beam power, inert gas flow, cooling of Zr-based alloys, and Cr powder control. This technology was then applied to Zr cladding tube samples to study the effect of Cr coating on the high-temperature oxidation of Zr-based alloys in a steam environment of 1200 °C for 2000s. It was revealed that the oxide layer thickness formed on the Cr-coated tube surface was about 25-times lower than that formed on a Zircaloy-4 tube surface. In addition, both the ring compression and the tensile tests were performed to evaluate the adhesion properties of the Cr-coated sample. Although some cracks were formed on the Cr-coated layer, the Cr-coated layer had not peeled off after the two tests.

  7. 3D laser inspection of fuel assembly grid spacers for nuclear reactors based on diffractive optical elements

    Science.gov (United States)

    Finogenov, L. V.; Lemeshko, Yu A.; Zav'yalov, P. S.; Chugui, Yu V.

    2007-06-01

    Ensuring the safety and high operation reliability of nuclear reactors takes 100% inspection of geometrical parameters of fuel assemblies, which include the grid spacers performed as a cellular structure with fuel elements. The required grid spacer geometry of assembly in the transverse and longitudinal cross sections is extremely important for maintaining the necessary heat regime. A universal method for 3D grid spacer inspection using a diffractive optical element (DOE), which generates as the structural illumination a multiple-ring pattern on the inner surface of a grid spacer cell, is investigated. Using some DOEs one can inspect the nomenclature of all produced grids. A special objective has been developed for forming the inner surface cell image. The problems of diffractive elements synthesis, projecting optics calculation, adjusting methods as well as calibration of the experimental measuring system are considered. The algorithms for image processing for different constructive elements of grids (cell, channel hole, outer grid spacer rim) and the experimental results are presented.

  8. Technical note: Criterion validity of whole body surface area equations: a comparison using 3D laser scanning.

    Science.gov (United States)

    Daniell, Nathan; Olds, Timothy; Tomkinson, Grant

    2012-05-01

    Measurements of whole body surface area (WBSA) have important applications in numerous fields including biological anthropology, clinical medicine, biomechanics, and sports science. Currently, WBSA is most often estimated using predictive equations due to the complex and time consuming methods required for direct measurement. The main aim of this study was to identify whether there were significant and meaningful differences between WBSA measurements taken using a whole body three-dimensional (3D) scanner (criterion measure) and the estimates derived from each WBSA equation identified from a systematic review. The study also aimed to determine whether differences varied according to body mass index (BMI), sex, or athletic status. Fifteen WBSA equations were compared with direct measurements taken on 1,714 young adult subjects, aged 18-30 years, using the Vitus Smart 3D whole body scanner, including 1,452 subjects (753 males, 699 females) from the general Australian population and 262 rowers (148 males, 114 females). Mixed-design analysis of variances determined significant differences and accuracy was quantified using Bland-Altman analysis and effect sizes. Thirteen of the 15 equations overestimated WBSA. With a few exceptions, equations were accurate with a low-systematic error (bias ≤2%) and low-random error (standard deviation of the differences 1.5-3.0%). However, BMI did have a substantial impact with the accuracy of some WBSA equations varying between the four BMI categories. The Shuter and Aslani: Eur J Appl Physiol 82 (2000) 250-254 equation was identified as the most accurate equation and should be used for Western populations 18-30 years of age. Care must be taken when deciding which equation to use when estimating WBSA.

  9. Standing-wave-excited multiplanar fluorescence in a laser scanning microscope reveals 3D information on red blood cells

    CERN Document Server

    Amor, Rumelo; Amos, William Bradshaw; McConnell, Gail

    2014-01-01

    Standing-wave excitation of fluorescence is highly desirable in optical microscopy because it improves the axial resolution. We demonstrate here that multiplanar excitation of fluorescence by a standing wave can be produced in a single-spot laser scanning microscope by placing a plane reflector close to the specimen. We report that the relative intensities in each plane of excitation depend on the Stokes shift of the fluorochrome. We show by the use of dyes specific for the cell membrane how standing-wave excitation can be exploited to generate precise contour maps of the surface membrane of red blood cells, with an axial resolution of ~90 nm. The method, which requires only the addition of a plane mirror to an existing confocal laser scanning microscope, may well prove useful in studying diseases which involve the red cell membrane, such as malaria.

  10. Boresight calibration of construction misalignments for 3D scanners built with a 2D laser range finder rotating on its optical center.

    Science.gov (United States)

    Morales, Jesús; Martínez, Jorge L; Mandow, Anthony; Reina, Antonio J; Pequeño-Boter, Alejandro; García-Cerezo, Alfonso

    2014-10-24

    Many applications, like mobile robotics, can profit from acquiring dense, wide-ranging and accurate 3D laser data. Off-the-shelf 2D scanners are commonly customized with an extra rotation as a low-cost, lightweight and low-power-demanding solution. Moreover, aligning the extra rotation axis with the optical center allows the 3D device to maintain the same minimum range as the 2D scanner and avoids offsets in computing Cartesian coordinates. The paper proposes a practical procedure to estimate construction misalignments based on a single scan taken from an arbitrary position in an unprepared environment that contains planar surfaces of unknown dimensions. Inherited measurement limitations from low-cost 2D devices prevent the estimation of very small translation misalignments, so the calibration problem reduces to obtaining boresight parameters. The distinctive approach with respect to previous plane-based intrinsic calibration techniques is the iterative maximization of both the flatness and the area of visible planes. Calibration results are presented for a case study. The method is currently being applied as the final stage in the production of a commercial 3D rangefinder.

  11. On FAST3D simulations of directly-driven inertial-fusion targets with high-Z layers for reducing laser imprint and surface non-uniformity growth

    Science.gov (United States)

    Bates, Jason; Schmitt, Andrew; Klapisch, Marcel; Karasik, Max; Obenschain, Steve

    2013-10-01

    Modifications to the FAST3D code have been made to enhance its ability to simulate the dynamics of plastic ICF targets with high-Z overcoats. This class of problems is challenging computationally due in part to plasma conditions that are not in a state of local thermodynamic equilibrium and to the presence of mixed computational cells containing more than one material. Recently, new opacity tables for gold, palladium and plastic have been generated with an improved version of the STA code. These improved tables provide smoother, higher-fidelity opacity data over a wider range of temperature and density states than before, and contribute to a more accurate treatment of radiative transfer processes in FAST3D simulations. Furthermore, a new, more efficient subroutine known as ``MMEOS'' has been installed in the FAST3D code for determining pressure and temperature equilibrium conditions within cells containing multiple materials. We will discuss these topics, and present new simulation results for high-Z planar-target experiments performed recently on the NIKE Laser Facility. Work supported by DOE/NNSA.

  12. 3D photoacoustic imaging

    Science.gov (United States)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    Our group has concentrated on development of a 3D photoacoustic imaging system for biomedical imaging research. The technology employs a sparse parallel detection scheme and specialized reconstruction software to obtain 3D optical images using a single laser pulse. With the technology we have been able to capture 3D movies of translating point targets and rotating line targets. The current limitation of our 3D photoacoustic imaging approach is its inability ability to reconstruct complex objects in the field of view. This is primarily due to the relatively small number of projections used to reconstruct objects. However, in many photoacoustic imaging situations, only a few objects may be present in the field of view and these objects may have very high contrast compared to background. That is, the objects have sparse properties. Therefore, our work had two objectives: (i) to utilize mathematical tools to evaluate 3D photoacoustic imaging performance, and (ii) to test image reconstruction algorithms that prefer sparseness in the reconstructed images. Our approach was to utilize singular value decomposition techniques to study the imaging operator of the system and evaluate the complexity of objects that could potentially be reconstructed. We also compared the performance of two image reconstruction algorithms (algebraic reconstruction and l1-norm techniques) at reconstructing objects of increasing sparseness. We observed that for a 15-element detection scheme, the number of measureable singular vectors representative of the imaging operator was consistent with the demonstrated ability to reconstruct point and line targets in the field of view. We also observed that the l1-norm reconstruction technique, which is known to prefer sparseness in reconstructed images, was superior to the algebraic reconstruction technique. Based on these findings, we concluded (i) that singular value decomposition of the imaging operator provides valuable insight into the capabilities of

  13. 仿人眼功能的三维激光扫描算法%3D laser scanning algorithm with humanoid-eye function

    Institute of Scientific and Technical Information of China (English)

    陈伟海; 宋蔚阳; 荣利霞; 刘敬猛

    2009-01-01

    Aiming at the scanning efficiency of three dimensional (3D) laser scanning system for mobile robot all over the world, a humanoid-eye 3D laser scanning algorithm was proposed. Imitating the scanning function of human eyes from bionics, this algorithm divides the scanning process into two steps: according to the scanning information currently, the scanning scheme of the next step will be planned to reduce the gain of useless information; Through adopting the stepping interpolation location to fetch up the time consuming from stepping scan, the efficiency of the scan can be improved. To satisfy the real-time requirement for the online computing, a hardware architecture consisting of digital signal processing (DSP) and field-programmable gate array (FPGA) was proposed. Therefore, as the main controller, DSP can obtain 3D laser data; as the coprocessor, FPGA can complete the scanning algorithm. The experiment result shows the humanoid-eye scanning algorithm can improve the efficiency of the 3D scanning system greatly.%针对目前国内外应用于移动机器人的三维激光扫描系统存在的扫描效率问 题,提出了一种仿人眼功能的三维激光扫描算法.从仿生学角度出发,该算法模仿人类眼睛的 扫描功能,对陌生环境进行分步扫描:根据当前的扫描信息,在线规划出下一步的扫描规律,以 减少无用信息的获取;采用分步插补定位的方法来弥补分步扫描带来的时间消耗,从而提高了 扫描系统的效率.为了满足扫描算法的在线处理对实时性的要求,采用了一种DSP(Digital Sig-nal Processing)+FPGA(Field-Programmable Gate Array)的硬件平台架构:即DSP作主控制器负 责三维信息的获取,FPGA作协处理器负责扫描算法的实现.实验结果表明仿人眼功能的扫描算法可以有效的提高三维扫描系统的扫描效率.

  14. Adolescent patient with bilateral crossbite treated with surgically assisted rapid maxillary expansion: a case report evaluated by the 3d laser scanner, and using FESA method.

    Science.gov (United States)

    Ivanov, Ch I; Velemínská, J; Dostálová, T; Foltán, R

    2011-01-01

    Our purpose in this case report is to present an orthodontic treatment obtained and the results achieved in 17-year-old white female patient with Angle Class II malocclusion and bilateral posterior crossbite. Patient was treated with bonded acrylic Hyrax appliance and surgically assisted rapid maxillary expansion (SARME). The multiloop system 0.16 TMA (ß titanium) arch wire was used in the alignment phase and on purpose to prohibit bite opening and optimize threedimensional movement control. After treatment bonded lingual retainers were placed in between maxillary central incisors and in mandible canine-to-canine. A functional removable Klammt appliance was used for retention. The 3D Laser Scanner Roland LPX-250 was used in order to obtain digital dental casts. Evaluation of the treatment results was measured on these models and using finite element scaling analysis (FESA). An Angle Class I relationship was obtained after 2½ years of treatment, function and facial aesthetics were improved. The shape of the palate changed significant in the width direction, not significantly in length and high direction. The greatest expansion of palate was found in the region between the palatal cusps of the first molars 26.6%, followed by first 21.9% and second premolars 16.5%. SARME in adult patients with bilateral cross bite and maxillary deficiency lead to satisfactory results. The 3D laser scanned models and their measurements, using advanced software's are successfully used for precise studies.

  15. Micro and nano-biomimetic structures for cell migration study fabricated by hybrid subtractive and additive 3D femtosecond laser processing

    Science.gov (United States)

    Sima, Felix; Serien, Daniela; Wu, Dong; Xu, Jian; Kawano, Hiroyuki; Midorikawa, Katsumi; Sugioka, Koji

    2017-02-01

    Lab-on-a-chip devices have been intensively developed during the last decade when emerging technologies offered possibilities to manufacture reliable devices with increased spatial resolution. These biochips allowed testing chemical reactions in nanoliter volumes with enhanced sensitivity and lower consumption of reagents. There is space to further consolidate biochip assembling processing since the new technologies attempt direct fabrication in view of reducing costs and time by increasing efficiency and functionalities. Rapid prototyping by ultrafast lasers which induces local modifications inside transparent materials of both glass and polymers with high precision at micro- and nanoscale is a promising tool for fabrication of such biochips. We have developed a new technology by combining subtractive ultrafast laser assisted chemical etching of glasses and additive two-photon polymerization to integrate 3D glass microfluidics and polymer microcomponents in a single biochip. The innovative hybrid "ship-in-a-bottle" approach is not only an instrument that can tailor 3D environments but also a tool to fabricate biomimetic in vivo structures inside a glass microfluidic chip. It was possible to create appropriate environment for cell culturing and to offer robustness and transparency for optical interrogation. Cancer cells were cultivated inside biochips and monitored over short and long periods. With the view of understanding cancer cells specific behavior such as migration or invasiveness inside human body, introduction of different geometrical configurations and chemical conditions were proposed. The cells were found responsive to a gradient of nutrient concentration through the microchannels of a 3D polymeric scaffold integrated inside glass biochip.

  16. IMU and Multiple RGB-D Camera Fusion for Assisting Indoor Stop-and-Go 3D Terrestrial Laser Scanning

    Directory of Open Access Journals (Sweden)

    Jacky C.K. Chow

    2014-07-01

    Full Text Available Autonomous Simultaneous Localization and Mapping (SLAM is an important topic in many engineering fields. Since stop-and-go systems are typically slow and full-kinematic systems may lack accuracy and integrity, this paper presents a novel hybrid “continuous stop-and-go” mobile mapping system called Scannect. A 3D terrestrial LiDAR system is integrated with a MEMS IMU and two Microsoft Kinect sensors to map indoor urban environments. The Kinects’ depth maps were processed using a new point-to-plane ICP that minimizes the reprojection error of the infrared camera and projector pair in an implicit iterative extended Kalman filter (IEKF. A new formulation of the 5-point visual odometry method is tightly coupled in the implicit IEKF without increasing the dimensions of the state space. The Scannect can map and navigate in areas with textureless walls and provides an effective means for mapping large areas with lots of occlusions. Mapping long corridors (total travel distance of 120 m took approximately 30 minutes and achieved a Mean Radial Spherical Error of 17 cm before smoothing or global optimization.

  17. A Method to Obtain Orange Crop Geometry Information Using a Mobile Terrestrial Laser Scanner and 3D Modeling

    Directory of Open Access Journals (Sweden)

    André F. Colaço

    2017-07-01

    Full Text Available LiDAR (Light Detection and Ranging technology has been used to obtain geometrical attributes of tree crops in small field plots, sometimes using manual steps in data processing. The objective of this study was to develop a method for estimating canopy volume and height based on a mobile terrestrial laser scanner suited for large commercial orange groves. A 2D LiDAR sensor and a GNSS (Global Navigation Satellite System receiver were mounted on a vehicle for data acquisition. A georeferenced point cloud representing the laser beam impacts on the crop was created and later classified into transversal sections along the row or into individual trees. The convex-hull and the alpha-shape reconstruction algorithms were used to reproduce the shape of the tree crowns. Maps of canopy volume and height were generated for a 25 ha orange grove. The different options of data processing resulted in different values of canopy volume. The alpha-shape algorithm was considered a good option to represent individual trees whereas the convex-hull was better when representing transversal sections of the row. Nevertheless, the canopy volume and height maps produced by those two methods were similar. The proposed system is useful for site-specific management in orange groves.

  18. Documenting a Complex Modern Heritage Building Using Multi Image Close Range Photogrammetry and 3d Laser Scanned Point Clouds

    Science.gov (United States)

    Vianna Baptista, M. L.

    2013-07-01

    Integrating different technologies and expertises help fill gaps when optimizing documentation of complex buildings. Described below is the process used in the first part of a restoration project, the architectural survey of Theatre Guaira Cultural Centre in Curitiba, Brazil. To diminish time on fieldwork, the two-person-field-survey team had to juggle, during three days, the continuous artistic activities and performers' intense schedule. Both technologies (high definition laser scanning and close-range photogrammetry) were used to record all details in the least amount of time without disturbing the artists' rehearsals and performances. Laser Scanning was ideal to record the monumental stage structure with all of its existing platforms, light fixtures, scenery walls and curtains. Although scanned with high-definition, parts of the exterior façades were also recorded using Close Range Photogrammetry. Tiny cracks on the marble plaques and mosaic tiles, not visible in the point clouds, were then able to be precisely documented in order to create the exterior façades textures and damages mapping drawings. The combination of technologies and the expertise of service providers, knowing how and what to document, and what to deliver to the client, enabled maximum benefits to the following restoration project.

  19. A system for the simulation and planning of orthodontic treatment using a low cost 3D laser scanner for dental anatomy capturing.

    Science.gov (United States)

    Alcañiz, M; Grau, V; Monserrat, C; Juan, C; Albalat, S

    1999-01-01

    The detection and correction of malocclusions and other dental abnormalities is a significant area of work in orthodontic diagnosis. To assess the quality of occlusion between the teeth the orthodontist has to estimate distances between specific points located on the teeth of both arches. Distance measuring is based on the observation, by the orthodontist, of a plaster model of the mouth. Gathering of information required to make the diagnosis is a time consuming and costly operation. On the other hand, obtaining and manipulation of plaster casts constitute a huge problem in clinics, due to both the large space needed and high costs associated with plaster casts manufacturing. For this problem we present a new system for three-dimensional orthodontic treatment planning and movement of teeth. We describe a computer vision technique for the acquisition and processing of three-dimensional images of the profile of hydrocolloids dental imprints taken by mean of a own developed 3D laser scanner. Profile measurement is based on the triangulation method which detects deformation of the projection of a laser line on the dental imprints. The system is computer-controlled and designed to achieve depth and lateral resolutions of 0.1 mm and 0.2 mm, respectively, within a depth range of 40 mm. The developed diagnosis software system (named MAGALLANES) and the 3D laser scanner (named 3DENT) are both commercially available and have been designed to replace manual measurement methods, which use costly plaster models, with computer measurements methods and teeth movement simulation using cheap hydrocolloid dental wafers. This procedure will reduce the cost and acquisition time of orthodontic data and facilitate the conduct of epidemiological studies.

  20. Comparison of 2D temperature maps recorded during laser-induced thermal tissue treatment with corresponding temperature distributions calculated from 3D Monte-Carlo simulations

    Science.gov (United States)

    Busse, Harald; Bublat, Martin; Ratering, Ralf; Rassek, Margarethe; Schwarzmaier, Hans-Joachim; Kahn, Thomas

    2000-05-01

    Minimally invasive techniques often require special biomedical monitoring schemes. In the case of laser coagulation of tumors accurate temperature mapping is desirable for therapy control. While magnetic resonance (MR)-based thermometry can easily yield qualitative results it is still difficult to calibrate this technique with independent temperature probes for the entire 2D field of view. Calculated temperature maps derived from Monte-Carlo simulations (MCS), on the other hand, are suitable for therapy planning and dosimetry but typically can not account for the extract individual tissue parameters and physiological changes upon heating. In this work, online thermometry was combined with MCS techniques to explore the feasibility and potential of such a biomodal approach for surgical assist systems. For the first time, the result of a 3D simulation were evaluated with MR techniques. An MR thermometry system was used to monitor the temperature evolution during laser-induced thermal treatment of bovine liver using a commercially available water-cooled applicator. A systematic comparison between MR-derived 2D temperature maps in different orientations and corresponding snapshots of a 3D MCS of the laser-induced processes is presented. The MCS is capable of resolving the complex temperature patterns observed in the MR-derived images and yields a good agreement with respect to absolute temperatures and damage volume dimensions. The observed quantitative agreement is around 10 degrees C and on the order of 10 percent, respectively. The integrated simulation-and-monitoring approach has the potential to improve surgical assistance during thermal interventions.

  1. 3D mapping of chemical distribution from melting at lower mantle conditions in the laser-heated diamond anvil cell

    Science.gov (United States)

    Dorfman, S. M.; Nabiei, F.; Cantoni, M.; Badro, J.; Gaal, R.; Gillet, P.

    2014-12-01

    The laser-heated diamond anvil cell is a unique tool for subjecting materials to pressures over few hundreds of GPa and temperatures of thousands of Kelvins which enables us to experimentally simulate the inaccessible interiors of planets. However, small sample size, laser profile and thermally conductive diamonds cause temperature gradients of 1000s K over a few microns which also affects chemical and structural distribution of phases in the sample. We have examined samples of San Carlos olivine (Mg,Fe)2SiO3 powder melted in the diamond anvil cell by double-sided and single-sided laser heating for 3-6 minutes to ~3000 K at 35-37 GPa. Moreover, MgO is used as an insulating media in one of the sample. Recovered samples were analyzed by a combination of focused ion beam (FIB) and scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) detector. Images and chemical maps were acquired for ~300 slices with ~70 nm depth from each sample, comprising about half of the heated zone. Detailed chemical and structural analysis by transmission electron microscopy (TEM) of lamellas prepared from the remaining section of the samples will also be presented. In all samples the heated zone included (Mg,Fe)SiO3 perovskite-structured bridgmanite (PV) phase and two (Mg, Fe)O phases, one of which, magnesiowüstite (MW), is richer in iron than the other one, ferropericlase (FP). In double-side heated samples we observe a Fe-rich quenched melt core surrounded by MW phase. Our results show that with increasing heating time, Fe migrates to the molten center of the sample. In the single-side heated sample, the Fe-rich MW phase is concentrated in the center of heated zone. In all samples a FP crust was observed around the heated zone. This crust, however, is broken in the upper part (colder part) of the single-side heated sample due the high asymmetrical temperature gradient within the sample. The results confirm the importance of double-side heating and insulating media

  2. Feasibility Study on 3-D Printing of Metallic Structural Materials with Robotized Laser-Based Metal Additive Manufacturing

    Science.gov (United States)

    Ding, Yaoyu; Kovacevic, Radovan

    2016-07-01

    Metallic structural materials continue to open new avenues in achieving exotic mechanical properties that are naturally unavailable. They hold great potential in developing novel products in diverse industries such as the automotive, aerospace, biomedical, oil and gas, and defense. Currently, the use of metallic structural materials in industry is still limited because of difficulties in their manufacturing. This article studied the feasibility of printing metallic structural materials with robotized laser-based metal additive manufacturing (RLMAM). In this study, two metallic structural materials characterized by an enlarged positive Poisson's ratio and a negative Poisson's ratio were designed and simulated, respectively. An RLMAM system developed at the Research Center for Advanced Manufacturing of Southern Methodist University was used to print them. The results of the tensile tests indicated that the printed samples successfully achieved the corresponding mechanical properties.

  3. Nonlinear automatic landing control of unmanned aerial vehicles on moving platforms via a 3D laser radar

    Science.gov (United States)

    Hervas, Jaime Rubio; Reyhanoglu, Mahmut; Tang, Hui

    2014-12-01

    This paper presents a motion tracking and control system for automatically landing Unmanned Aerial Vehicles (UAVs) on an oscillating platform using Laser Radar (LADAR) observations. The system itself is assumed to be mounted on a ship deck. A full nonlinear mathematical model is first introduced for the UAV. The ship motion is characterized by a Fourier transform based method which includes a realistic characterization of the sea waves. LADAR observation models are introduced and an algorithm to process those observations for yielding the relative state between the vessel and the UAV is presented, from which the UAV's state relative to an inertial frame can be obtained and used for feedback purposes. A sliding mode control algorithm is derived for tracking a landing trajectory defined by a set of desired waypoints. An extended Kalman filter (EKF) is proposed to account for process and observation noises in the design of a state estimator. The effectiveness of the control algorithm is illustrated through a simulation example.

  4. Surface 3D Micro Free Forms: Multifunctional Microstructured Mesoporous α-Alumina by in Situ Slip Casting Using Excimer Laser Ablated Polycarbonate Molds.

    Science.gov (United States)

    Rowthu, Sriharitha; Böhlen, Karl; Bowen, Paul; Hoffmann, Patrik

    2015-11-11

    Ceramic surface microstructuring is a rapidly growing field with a variety of applications in tribology, wetting, biology, and so on. However, there are limitations to large-area microstructuring and fabrication of three-dimensional (3D) micro free forms. Here, we present a route to obtain intricate surface structures through in situ slip casting using polydimethylsiloxane (PDMS) negative molds which are replicated from excimer laser ablated polycarbonate (PC) master molds. PC sheets are ablated with a nanosecond KrF (λ = 248 nm) excimer laser mask projection system to obtain micron-scale 3D surface features over a large area of up to 3 m(2). Complex surface structures that include 3D free forms such as 3D topography of Switzerland, shallow structures such as diffractive optical elements (60 nm step) and conical micropillars have been obtained. The samples are defect-free produced with thicknesses of up to 10 mm and 120 mm diameter. The drying process of the slip cast alumina slurry takes place as a one-dimensional process, through surface evaporation and water permeation through the PDMS membrane. This allows homogeneous one-dimensional shrinkage during the drying process, independent of the sample's lateral dimensions. A linear mass diffusion model has been proposed to predict and explain the drying process of these ceramic colloidal suspensions. The calculated drying time is linearly proportional to the height of the slurry and the thickness of the negatively structured PDMS and is validated by the experimental results. An experimentally observed optimum Sylgard PDMS thickness range of ∼400 μm to 1 mm has achieved the best quality microstructured green compacts. Further, the model predicts that the drying time is independent of the microstructured areas and was validated using experimental observations carried out with microstructured areas of 300 mm(2), 1200 mm(2), and 120 cm(2). Therefore, in principle, the structures can be further replicated in areas up

  5. Make or Buy: An Analysis of the Impacts of 3D Printing Operations, 3D Laser Scanning Technology, and Collaborative Product Lifecycle Management on Ship Maintenance and Modernization Cost Savings

    Science.gov (United States)

    2015-03-21

    deposition . Beam deposition is predominantly used for metal powders . It is similar to the SLS technique in that it uses laser as a focused heat source to...some of them use a high-power laser beam to melt a very fine metal powder in order to form a thin layer, while some others use UV light to...based systems. • Beam Deposition : The beam deposition (BD) process is referred to as laser engineered net shaping (LENS), laser metal

  6. Tracking 3D Moving Objects Based on GPS/IMU Navigation Solution, Laser Scanner Point Cloud and GIS Data

    Directory of Open Access Journals (Sweden)

    Siavash Hosseinyalamdary

    2015-07-01

    Full Text Available Monitoring vehicular road traffic is a key component of any autonomous driving platform. Detecting moving objects, and tracking them, is crucial to navigating around objects and predicting their locations and trajectories. Laser sensors provide an excellent observation of the area around vehicles, but the point cloud of objects may be noisy, occluded, and prone to different errors. Consequently, object tracking is an open problem, especially for low-quality point clouds. This paper describes a pipeline to integrate various sensor data and prior information, such as a Geospatial Information System (GIS map, to segment and track moving objects in a scene. We show that even a low-quality GIS map, such as OpenStreetMap (OSM, can improve the tracking accuracy, as well as decrease processing time. A bank of Kalman filters is used to track moving objects in a scene. In addition, we apply non-holonomic constraint to provide a better orientation estimation of moving objects. The results show that moving objects can be correctly detected, and accurately tracked, over time, based on modest quality Light Detection And Ranging (LiDAR data, a coarse GIS map, and a fairly accurate Global Positioning System (GPS and Inertial Measurement Unit (IMU navigation solution.

  7. MODELLING OF AN INEXPENSIVE 9M SATELLITE DISH FROM 3D POINT CLOUDS CAPTURED BY TERRESTRIAL LASER SCANNERS

    Directory of Open Access Journals (Sweden)

    D. Belton

    2012-09-01

    Full Text Available This paper presents the use of Terrestrial laser scanners (TLS to model the surface of satellite dish. In this case, the dish was an inexpensive 9m parabolic satellite dish with a mesh surface, and was to be utilised in radio astronomy. The aim of the modelling process was to determine the deviation of the surface away from its true parabolic shape, in order to estimate the surface efficiency with respect to its principal receiving frequency. The main mathematical problems were the optimal and unbiased estimation the orientation of the dish and the fitting of a parabola to the local orientation or coordinate system, which were done by both orthogonal and algebraic minimization using the least-squares method. Due to the mesh structure of the dish, a classification method was also applied to filter out erroneous points being influenced by the supporting structure behind the dish. Finally, a comparison is performed between the ideal parabolic shape, and the data collected from three different temporal intervals.

  8. 3-D matrix template-assisted growth of oriented oxide nanowire arrays using glancing angle pulsed laser deposition

    Science.gov (United States)

    Wright, N.; Mateo-Feliciano, D.; Ostoski, A.; Mukherjee, P.; Witanachchi, S.

    Nanosphere lithography is a combination of different methods to nanofabrication. In this work nanosphere lithography is used to study the growth of Zinc Oxide Nano-columns (ZnO NCs) on different diameter Silica Nanosphere (SNS) self-assembled templates. ZnO NCs are promising building blocks for many existing and emerging optical, electrical, and piezoelectric devices, specifically, the seeded growth of other oxide materials. Recently, reports have shown a ferroelectric phase of zinc stannate (ZnSnO3) and while lead zirconium titanate oxide (PZT) has been the main material of interest in ferroelectric and piezoelectric applications, the toxicity of lead has been of great concern. The possibility of developing lead free piezoelectric materials is of great interest in the ferroelectric community. Langmuir-Blodgett method was used to construct a self-assembled monolayer of SNSs on silicon substrates. Oriented ZnO NCs were grown on top of the spheres using the glancing angle pulsed laser deposition technique. Columns were formed in a spatially ordered closed-packed hexagonal configuration. Growth of ZnO NCs was studied as function of ambient Oxygen pressure with SNS size ranging from 250-1000 nm. Cross-sectional Scanning Electron Microscopy and X-ray diffraction (XRD) were used to study the template structure. Relative aspect ratios were studied and showed tunability of column dimensions with sphere size. XRD revealed ZnO NC arrays were c-axis oriented with hexagonal wurtzite structure.

  9. Nonlinear automatic landing control of unmanned aerial vehicles on moving platforms via a 3D laser radar

    Energy Technology Data Exchange (ETDEWEB)

    Hervas, Jaime Rubio; Tang, Hui [School of Mechanical and Aerospace Engineering, Nanyang Technological University, Singapore, 639798 (Singapore); Reyhanoglu, Mahmut [Physical Sciences Department, Embry-Riddle Aeronautical University, Daytona Beach, FL 32114 (United States)

    2014-12-10

    This paper presents a motion tracking and control system for automatically landing Unmanned Aerial Vehicles (UAVs) on an oscillating platform using Laser Radar (LADAR) observations. The system itself is assumed to be mounted on a ship deck. A full nonlinear mathematical model is first introduced for the UAV. The ship motion is characterized by a Fourier transform based method which includes a realistic characterization of the sea waves. LADAR observation models are introduced and an algorithm to process those observations for yielding the relative state between the vessel and the UAV is presented, from which the UAV's state relative to an inertial frame can be obtained and used for feedback purposes. A sliding mode control algorithm is derived for tracking a landing trajectory defined by a set of desired waypoints. An extended Kalman filter (EKF) is proposed to account for process and observation noises in the design of a state estimator. The effectiveness of the control algorithm is illustrated through a simulation example.

  10. 3D Imaging of Porous Media Using Laser Scanning Confocal Microscopy with Application to Microscale Transport Processes

    Energy Technology Data Exchange (ETDEWEB)

    Fredrich, J.T.

    1999-02-10

    We present advances in the application of laser scanning confocal microscopy (LSCM) to image, reconstruct, and characterize statistically the microgeometry of porous geologic and engineering materials. We discuss technical and practical aspects of this imaging technique, including both its advantages and limitations. Confocal imaging can be used to optically section a material, with sub-micron resolution possible in the lateral and axial planes. The resultant volumetric image data, consisting of fluorescence intensities for typically {approximately}50 million voxels in XYZ space, can be used to reconstruct the three-dimensional structure of the two-phase medium. We present several examples of this application, including studying pore geometry in sandstone, characterizing brittle failure processes in low-porosity rock deformed under triaxial loading conditions in the laboratory, and analyzing the microstructure of porous ceramic insulations. We then describe approaches to extract statistical microgeometric descriptions from volumetric image data, and present results derived from confocal volumetric data sets. Finally, we develop the use of confocal image data to automatically generate a three-dimensional mesh for numerical pore-scale flow simulations.

  11. Extraction and Simplification of Building Façade Pieces from Mobile Laser Scanner Point Clouds for 3D Street View Services

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-12-01

    Full Text Available Extraction and analysis of building façades are key processes in the three-dimensional (3D building reconstruction and realistic geometrical modeling of the urban environment, which includes many applications, such as smart city management, autonomous navigation through the urban environment, fly-through rendering, 3D street view, virtual tourism, urban mission planning, etc. This paper proposes a building facade pieces extraction and simplification algorithm based on morphological filtering with point clouds obtained by a mobile laser scanner (MLS. First, this study presents a point cloud projection algorithm with high-accuracy orientation parameters from the position and orientation system (POS of MLS that can convert large volumes of point cloud data to a raster image. Second, this study proposes a feature extraction approach based on morphological filtering with point cloud projection that can obtain building facade features in an image space. Third, this study designs an inverse transformation of point cloud projection to convert building facade features from an image space to a 3D space. A building facade feature with restricted facade plane detection algorithm is implemented to reconstruct façade pieces for street view service. The results of building facade extraction experiments with large volumes of point cloud from MLS show that the proposed approach is suitable for various types of building facade extraction. The geometric accuracy of building façades is 0.66 m in x direction, 0.64 in y direction and 0.55 m in the vertical direction, which is the same level as the space resolution (0.5 m of the point cloud.

  12. Spatial variability and reproducibility of GABA-edited MEGA-LASER 3D-MRSI in the brain at 3 T.

    Science.gov (United States)

    Hnilicová, Petra; Považan, Michal; Strasser, Bernhard; Andronesi, Ovidiu C; Gajdošík, Martin; Dydak, Ulrike; Ukropec, Jozef; Dobrota, Dušan; Trattnig, Siegfried; Bogner, Wolfgang

    2016-11-01

    The reproducibility of gamma-aminobutyric acid (GABA) quantification results, obtained with MRSI, was determined on a 3 T MR scanner in healthy adults. In this study, a spiral-encoded, GABA-edited, MEGA-LASER MRSI sequence with real-time motion-scanner-instability corrections was applied for robust 3D mapping of neurotransmitters in the brain. In particular, the GABA(+) (i.e. GABA plus macromolecule contamination) and Glx (i.e. glutamate plus glutamine contamination) signal was measured. This sequence enables 3D-MRSI with about 3 cm(3) nominal resolution in about 20 min. Since reliable quantification of GABA is challenging, the spatial distribution of the inter-subject and intra-subject variability of GABA(+) and Glx levels was studied via test-retest assessment in 14 healthy volunteers (seven men-seven women). For both inter-subject and intra-subject repeated measurement sessions a low coefficient of variation (CV) and a high intraclass correlation coefficient (ICC) were found for GABA(+) and Glx ratios across all evaluated voxels (intra-/inter-subject: GABA(+) ratios, CV ~ 8%-ICC > 0.75; Glx ratios, CV ~ 6%-ICC > 0.70). The same was found in selected brain regions for Glx ratios versus GABA(+) ratios (CV varied from about 5% versus about 8% in occipital and parietal regions, to about 8% versus about 10% in the frontal area, thalamus, and basal ganglia). These results provide evidence that 3D mapping of GABA(+) and Glx using the described methodology provides high reproducibility for application in clinical and neuroscientific studies.

  13. The Application of 3D Laser Scanning in the Survey and Measuring of Guyue Bridge of Song Dynasty in Yiwu City

    Science.gov (United States)

    Lu, N.; Wang, Q.; Wang, S.; Zhang, R.

    2015-08-01

    It is believed that folding-arch is the transitional form from beam to curved arch. Guyue Bridge, built in JiaDing 6year (A.D 1213) of Southern Song Dynasty, located in Yiwu City, Zhejiang Province in China, is one of typical objective examples for this transition. It possesses high historical, scientific, artistic, cultural and social values. Facing severe environmental problems and deteriorated heritage situation, our conservation team selected 3D laser scanning as basic recording method, then acquired the precise threedimensional model. Measured the fundamental dimension and components' sizes, we analysed its stable state. Moreover, combined with historic documents, we reasonably speculated and calculated the original sizes and important scales at the building time. These findings have significant research values as well as evidential meanings for future conservation.

  14. The use of 3D laser imaging and a new breast replica cast as a method to optimize autologous breast reconstruction after mastectomy.

    Science.gov (United States)

    Ahcan, Uros; Bracun, Drago; Zivec, Katarina; Pavlic, Rok; Butala, Peter

    2012-04-01

    Aesthetically pleasing and symmetrical breasts are the goal of reconstructive breast surgery. Sometimes, however, multiple procedures are needed to improve a reconstructed breast's symmetry and appearance. In order to avoid additional corrective procedures, we have developed a new method that uses a reverse engineering technique to produce what we call a new breast replica cast (NBRC). The NBRC is a mould of the contralateral healthy breast, designed according to preoperative laser 3D images. During surgery, the mould is used to help shape the new breast. With this method, we are able to achieve breast symmetry in terms of volume, projection, contour, and position on the chest wall more accurately, more quickly, and more safely than before. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. 2D and 3D documentation of St. Nicolas baroque church for the general reconstruction using laser scanning and photogrammetry technologies combination

    Science.gov (United States)

    Křemen, Tomáš; Koska, Bronislav

    2013-04-01

    Total reconstruction of a historical object is a complicated process consisting of several partial steps. One of these steps is acquiring high-quality data for preparation of the project documentation. If these data are not available from the previous periods, it is necessary to proceed to a detailed measurement of the object and to create a required drawing documentation. New measurement of the object brings besides its costs also several advantages as complex content and form of drawings exactly according to the requirements together with their high accuracy. The paper describes measurement of the Baroque church by the laser scanning method extended by the terrestrial and air photogrammetry. It deals with processing the measured data and creating the final outputs, which is a 2D drawing documentation, orthophotos and a 3D model. Attention is focused on their problematic parts like interconnection of the measurement data acquired by various technologies, creation of orthophotos and creation of the detailed combined 3D model of the church exterior. Results of this work were used for preparation of the planned reconstruction of the object.

  16. Rapid Laser Photosensitive Resin 3D Printing Plotter%绘图仪式高速激光树脂3D打印设备研制

    Institute of Scientific and Technical Information of China (English)

    晏恒峰; 方浩博; 陈继民

    2015-01-01

    In order to further explore the realization method of 3D printing, and to get a promotion in the precision and efficiency, based on the structure of the plotter, combined with the stereolithography (SLA) technology, a new stereolithography plotter ( SLP) design was presented for 3D printing with photosensitive resin. Its movement structure was similar with the plotter, and laser focus part did xy two-dimensional motion directly. Its focus length was much shorter than that of SLA, so its power requirement of light source was lower. Compared to the SLA and digital light processing ( DLP), its work field can be extended more easily.%为了进一步探索3D打印实现方法,提高精度和效率,在绘图仪的结构基础上,结合光固化立体打印技术(SLA)的原理,设计了一种用于树脂材料的绘图仪式3D打印设备(SLP),它拥有绘图仪式的运动结构,激光及聚焦部分可直接做xy二维运动. 相对于SLA技术,SLP大幅减小了焦距,所以对光源的要求更低. 相比SLA和数字光处理技术(DLP),SLP加工幅面更容易扩大.

  17. 3D imaging of hematoxylin and eosin stained thick tissues with a sub-femtoliter resolution by using Cr:forsterite-laser-based nonlinear microscopy (Conference Presentation)

    Science.gov (United States)

    Kao, Chien-Ting; Wei, Ming-Liang; Liao, Yi-Hua; Sun, Chi-Kuang

    2017-02-01

    Intraoperative assessment of excision tissues during cancer surgery is clinically important. The assessment is used to be guided by the examination for residual tumor with frozen pathology, while it is time consuming for preparation and is with low accuracy for diagnosis. Recently, reflection confocal microscopy (RCM) and nonlinear microscopy (NLM) were demonstrated to be promising methods for surgical border assessment. Intraoperative RCM imaging may enable detection of residual tumor directly on skin cancers patients during Mohs surgery. The assessment of benign and malignant breast pathologies in fresh surgical specimens was demonstrated by NLM. Without using hematoxylin and eosin (H and E) that are common dyes for histopathological diagnosis, RCM was proposed to image in vivo by using aluminum chloride for nuclear contrast on surgical wounds directly, while NLM was proposed to detect two photon fluorescence nuclear contrast from acrdine orange staining. In this paper, we propose and demonstrate 3D imaging of H and E stained thick tissues with a sub-femtoliter resolution by using Cr:forsterite-laser-based NLM. With a 1260 nm femtosecond Cr:forsterite laser as the excitation source, the hematoxylin will strongly enhance the third-harmonic generation (THG) signals, while eosin will illuminate strong fluorescence under three photon absorption. Compared with previous works, the 1260 nm excitation light provide high penetration and low photodamage to the exercised tissues so that the possibility to perform other follow-up examination will be preserved. The THG and three-photon process provides high nonlinearity so that the super resolution in 3D is now possible. The staining and the contrast of the imaging is also fully compatible with the current clinical standard on frozen pathology thus facilitate the rapid intraoperative assessment of excision tissues. This work is sponsored by National Health Research Institutes and supported by National Taiwan University

  18. Motion-capture-based walking simulation of digital human adapted to laser-scanned 3D as-is environments for accessibility evaluation

    Directory of Open Access Journals (Sweden)

    Tsubasa Maruyama

    2016-07-01

    Full Text Available Owing to our rapidly aging society, accessibility evaluation to enhance the ease and safety of access to indoor and outdoor environments for the elderly and disabled is increasing in importance. Accessibility must be assessed not only from the general standard aspect but also in terms of physical and cognitive friendliness for users of different ages, genders, and abilities. Meanwhile, human behavior simulation has been progressing in the areas of crowd behavior analysis and emergency evacuation planning. However, in human behavior simulation, environment models represent only “as-planned” situations. In addition, a pedestrian model cannot generate the detailed articulated movements of various people of different ages and genders in the simulation. Therefore, the final goal of this research was to develop a virtual accessibility evaluation by combining realistic human behavior simulation using a digital human model (DHM with “as-is” environment models. To achieve this goal, we developed an algorithm for generating human-like DHM walking motions, adapting its strides, turning angles, and footprints to laser-scanned 3D as-is environments including slopes and stairs. The DHM motion was generated based only on a motion-capture (MoCap data for flat walking. Our implementation constructed as-is 3D environment models from laser-scanned point clouds of real environments and enabled a DHM to walk autonomously in various environment models. The difference in joint angles between the DHM and MoCap data was evaluated. Demonstrations of our environment modeling and walking simulation in indoor and outdoor environments including corridors, slopes, and stairs are illustrated in this study.

  19. 3D digital image processing for biofilm quantification from confocal laser scanning microscopy: Multidimensional statistical analysis of biofilm modeling

    Science.gov (United States)

    Zielinski, Jerzy S.

    The dramatic increase in number and volume of digital images produced in medical diagnostics, and the escalating demand for rapid access to these relevant medical data, along with the need for interpretation and retrieval has become of paramount importance to a modern healthcare system. Therefore, there is an ever growing need for processed, interpreted and saved images of various types. Due to the high cost and unreliability of human-dependent image analysis, it is necessary to develop an automated method for feature extraction, using sophisticated mathematical algorithms and reasoning. This work is focused on digital image signal processing of biological and biomedical data in one- two- and three-dimensional space. Methods and algorithms presented in this work were used to acquire data from genomic sequences, breast cancer, and biofilm images. One-dimensional analysis was applied to DNA sequences which were presented as a non-stationary sequence and modeled by a time-dependent autoregressive moving average (TD-ARMA) model. Two-dimensional analyses used 2D-ARMA model and applied it to detect breast cancer from x-ray mammograms or ultrasound images. Three-dimensional detection and classification techniques were applied to biofilm images acquired using confocal laser scanning microscopy. Modern medical images are geometrically arranged arrays of data. The broadening scope of imaging as a way to organize our observations of the biophysical world has led to a dramatic increase in our ability to apply new processing techniques and to combine multiple channels of data into sophisticated and complex mathematical models of physiological function and dysfunction. With explosion of the amount of data produced in a field of biomedicine, it is crucial to be able to construct accurate mathematical models of the data at hand. Two main purposes of signal modeling are: data size conservation and parameter extraction. Specifically, in biomedical imaging we have four key problems

  20. 3D video

    CERN Document Server

    Lucas, Laurent; Loscos, Céline

    2013-01-01

    While 3D vision has existed for many years, the use of 3D cameras and video-based modeling by the film industry has induced an explosion of interest for 3D acquisition technology, 3D content and 3D displays. As such, 3D video has become one of the new technology trends of this century.The chapters in this book cover a large spectrum of areas connected to 3D video, which are presented both theoretically and technologically, while taking into account both physiological and perceptual aspects. Stepping away from traditional 3D vision, the authors, all currently involved in these areas, provide th

  1. 3D Animation Essentials

    CERN Document Server

    Beane, Andy

    2012-01-01

    The essential fundamentals of 3D animation for aspiring 3D artists 3D is everywhere--video games, movie and television special effects, mobile devices, etc. Many aspiring artists and animators have grown up with 3D and computers, and naturally gravitate to this field as their area of interest. Bringing a blend of studio and classroom experience to offer you thorough coverage of the 3D animation industry, this must-have book shows you what it takes to create compelling and realistic 3D imagery. Serves as the first step to understanding the language of 3D and computer graphics (CG)Covers 3D anim

  2. The Structure of the Kaali Impact Crater (Estonia) based on 3D Laser Scanning, Photogrammetric Modelling and Strike and Dip Measurements

    Science.gov (United States)

    Zanetti, Michael; Wilk, Jakob; Joeleht, Argo; Välja, Rudolf; Losiak, Anna; Wisniowski, Tomek; Huber, Matthew; Pavel, Kristiina; Kriiska, Aivar; Plado, Jüri; Geppert, Wolf Dietrich; Kukko, Antero; Kaartinen, Harri

    2015-04-01

    Introduction: The Kaali Impact Crater on the island of Saaremaa, Estonia (58.37° N, 22.67° E) is part of a crater-strewn-field consisting of nine identified craters, ranging in size from 110m (Kaali Main) to a few meters in diameter [1-3]. The strewn field was formed by the breakup of an IAB iron meteorite during atmospheric entry [4]. The main crater is due to its size an important crater to study the effects of small asteroidal impacts on terrestrial planets. Despite some anthropomorphic changes, the crater is well preserved. During a scientific expedition in August 2014, we mapped the crater in unprecedented detail using 3D laser scanning tools and made detailed strike and dip measurements of all outcrops. Additional measurements using ground-penetrating radar and electro-resistivity tomography we also conducted to further refine the subsurface crater morphology. The results include a high resolution topographic map of the crater, previously unreported observations of overturned ejecta, and refined morphometric estimates of the crater. Additionally, research conducted as part of the expedition has provided a new, best-estimate for the formation of the crater (3200a +/- 30 BP) based on 14C AMS dating of charcoal from within the ejecta blanket [Losiak et al., 2015, this conference]. Structural Mapping: Although Kaali Main has been the subject of previous investigation (e.g. [2,5,6]), most of the structural descriptions of the crater pre-date modern crater investigations. Strongly inclined blocks were previously considered being affected by erosion and slope processes, our new observations show that most high dip-angle features fit well with overall dip-angle systematics. The existence of the overturned flap can be demonstrated in at least four areas around the crater. 3D Laser Scanning: A point cloud containing 16 million data points was created using 43 individual scans from a tripod mounted Faro 3D 330x laser scanner. Scans were processed using Trimble

  3. An optical laser device for mapping 3D geometry of underwater karst structures: first tests in the Ox BelHa system, Yucatan, Mexico; Un dispositivo laser optico para la cartografia 3D de la geometria de estructuras karsticas submarinas: primeros resultados en el sistema de Ox BelHa, Yucatan, Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Schiller, A.; Renard, P.

    2016-07-01

    In the course of extended hydrological studies in the coastal Karst plain of Yucatan, near the town of Tulum amongst others, a novel laser scanning device was developed and applied for the acquisition of the 3d-geometry of ground water conduits. The method is derived from similar industrial systems and for the first time adapted to the specific measurement conditions in underwater cave systems. The device projects a laser line over the whole perimeter at a certain position. This line represents the intersection of a plane with the cave walls. The line is imaged with a wide angle camera system. Through proper design and calibration of the device it is possible to derive the true scale geometry of the perimeter via special image processing techniques. By acquiring regularly spaced images it is possible to reconstruct the true scale and 3 d-shape of a tunnel through the incorporation of location and attitude data. In a first test in the Ox Bel Ha under-water cave system, about 800 metres of tunnels have been scanned down to water depths of 20 metres. The raw data is further interpolated using the ODSIM-algorithm in order to delineate the 3D geometry of the cave system. The method provides easy, operable acquisition of the 3-D geometry of caves in clear water with superior resolution and speed and significantly facilitates the measurement in underwater tunnels as well as in dry tunnels. The data gathered represents crucial input to the study of the state, dynamics and genesis of the complex karst water regime. (Author)

  4. Study of hybrid laser / MAG welding process: characterization of the geometry and the hydrodynamics of the melt pool and development of a 3D thermal model; Etude du procede de soudage hybride laser/MAG: Caracterisation de la geometrie et de l'hydrodynamique du bain de fusion et developpement d'un modele 3D thermique

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, E.

    2010-11-15

    Hybrid laser/MIG-MAG welding shows high advantages compared to laser welding or GMAW arc welding used separately. Thanks to this process, higher productivity can be gained through higher welding speed, higher squeeze tolerance moreover possible improvement of the metallurgical properties of the weld seam can be obtained. However, many operating parameters have to be set up in order to achieve optimal process. The complex physical phenomena, which govern welding process, have to be understood in order to use efficiently this technique in mass production. Understanding of these phenomena is also necessary to program numerical simulations which fit to this process. In the first step, experimental studies have been carried out with GMAW, laser and hybrid welding on samples of S355 steel. Influence of operating parameters has been analyzed through films performed with speed camera and macro-graphies of weld seam cross section. Surface deformations of the melt pool, induced by the arc pressure, weld pool length, droplet detachment and welding speed, have been analyzed precisely from images of the surface melt pool. In a second step, a numerical model was developed using the COMSOL Multiphysics software for MAG, laser and hybrid laser/MAG welding processes. A 3D quasi-stationary model has been calculated from the temperature field within the metal. The originality of the MAG and hybrid model lies in the prediction of the melt pool surface profile used to determine the 3D geometry, by taking into account the material input. The influence of different parameters such as arc power and speed welding on the efficiency as well as the distribution radius of the arc power and the arc pressure are analyzed through validations with different experimental results and different calculation configurations. (author)

  5. Heat Equation to 3D Image Segmentation

    Directory of Open Access Journals (Sweden)

    Nikolay Sirakov

    2006-04-01

    Full Text Available This paper presents a new approach, capable of 3D image segmentation and objects' surface reconstruction. The main advantages of the method are: large capture range; quick segmentation of a 3D scene/image to regions; multiple 3D objects reconstruction. The method uses centripetal force and penalty function to segment the entire 3D scene/image to regions containing a single 3D object. Each region is inscribed in a convex, smooth closed surface, which defines a centripetal force. Then the surface is evolved by the geometric heat differential equation toward the force's direction. The penalty function is defined to stop evolvement of those surface patches, whose normal vectors encountered object's surface. On the base of the theoretical model Forward Difference Algorithm was developed and coded by Mathematica. Stability convergence condition, truncation error and calculation complexity of the algorithm are determined. The obtained results, advantages and disadvantages of the method are discussed at the end of this paper.

  6. Thermomechanical response of 3D laser-deposited Ti–6Al–4V alloy over a wide range of strain rates and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Li, Peng-Hui [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Guo, Wei-Guo, E-mail: weiguo@nwpu.edu.cn [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China); Huang, Wei-Dong [The State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Su, Yu [Department of Mechanics, School of Aerospace Engineering, Beijing Institute of Technology, Beijing 100081 (China); Lin, Xin [The State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072 (China); Yuan, Kang-Bo [School of Aeronautics, Northwestern Polytechnical University, Xi’an 710072 (China)

    2015-10-28

    To understand and evaluate the thermomechanical property of Ti–6Al–4V alloy prepared by the 3D laser deposition technology, an uniaxial compression test was performed on cylindrical samples using an electronic universal testing machine and enhanced Hopkinson technique, over the range of strain rate from 0.001/s to 5000/s, and at initial temperatures from the room temperature to 1173 K. The microstructure of the undeformed and deformed samples was examined through optical microscopy and the use of scanning electron microscope (SEM). The experimental results show the followings: (1) the anisotropy of the mechanical property of this alloy is not significant despite the visible stratification at the exterior surfaces; (2) initial defects, such as the initial voids and lack of fusion, are found in the microstructure and in the crack surfaces of the deformed samples, and they are considered as a major source of crack initiation and propagation; (3) adiabatic shear bands and shearing can easily develop at all selected temperatures for samples under compression; (4) the yield and ultimate strengths of this laser-deposited Ti–6Al–4V alloy are both lower than those of the Ti–6Al–4V alloy prepared by forging and electron beam melting, whereas both of its strengths are higher than those of a conventional grade Ti–6Al–4V alloy at high strain rate only. In addition to compression tests we also conducted tensile loading tests on the laser-deposited alloy at both low and high strain rates (0.1/s and 1000/s). There is significant tension/compression asymmetry in the mechanical response under high-strain-rate loading. It was found that the quasi-static tensile fracturing exhibits typical composite fracture characteristic with quasi-cleavages and dimples, while the high-strain-rate fracturing is characterized by ductile fracture behavior.

  7. The effect of near-infrared laser beam on the surface modification of metal complex based on 3D laser scanning system

    Science.gov (United States)

    Zhao, Mali; Liu, Tiegen; Jiang, Junfeng; Wang, Meng

    2014-11-01

    High-precision 3-dimensional metallization is difficult to realize in specific nonmetallic areas by using the traditional methods such as wet-chemical and mechanical methods because of the disadvantage that usually they cannot achieve selective modification. In this paper, 3-dimensional laser scanning system was applied to achieve the modification of specific regions of the sample surface. In 3-dimensional laser scanning system, the laser beam, after going through dynamic focusing system, was reflected by galvanometers and then focused by f-theta lens on the sample surface. The changes in surface characteristics of the blends of polycarbonate and acrylonitrile butadiene styrene copolymers (PC/ABS) mixed with Cu-Cr complex by the laser irradiation with the wavelength of 1064nm were investigated. Through analysis it was found that the smooth surface of the original samples was changed to a micro-hole structure accompanied by an increased surface roughness as well as an increased water contact angle. The chemical composition percentage had changed and the metal components of copper and chromium were detected after the laser irradiation. The irradiated areas were degraded into organic ligand fragments, volatile gas and reducing metal ions of copper and chromium. Besides, the thickness of the deposited metal layer and the adhesive force between the metal layer and the substrate after electroless plating varied according to the laser parameters such as frequency and scanning speed. As shown in the experiment, the thickness of deposited copper layer exceeded 11μm and the deposited nickel layer exceeded 2μm respectively.

  8. Doppler-free intermodulated fluorescence spectroscopy of $^4He$ $2^3P-3^{1,3}D$ transitions at 588 nm with a one-watt compact laser system

    CERN Document Server

    Luo, Pei-Ling; Feng, Yan; Wang, Li-Bang; Shy, Jow-Tsong

    2015-01-01

    We have demonstrated Doppler-free intermodulated fluorescence spectroscopy of helium $2^3P-3^{1,3}D$ transitions in an rf discharged sealed-off cell using a compact laser system at 588 nm. An external cavity diode laser at 1176 nm was constructed to seed a Raman fiber amplifier. Laser power of more than one watt at 588 nm was produced by frequency doubling of the fiber amplifier output using a MgO:PPLN crystal. A doubling efficiency of 23 % was achieved. The power-dependent spectra of the $2^3P-3^3D$ transitions were investigated. Furthermore, the Doppler-free spectrum of the spin-forbidden $2^3P-3^1D$ transitions was observed for the first time. Our results are crucial towards precision test of QED atomic calculations, especially for improving the determination of the helium $3^1D-3^3D$ separation.

  9. EUROPEANA AND 3D

    Directory of Open Access Journals (Sweden)

    D. Pletinckx

    2012-09-01

    Full Text Available The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  10. Innovative design for a cutting head rotary mechanism of 3D laser cutting machine%一种三维激光切割机激光头旋转机构的创新设计

    Institute of Scientific and Technical Information of China (English)

    龚立新; 周鹏飞; 胡金龙; 孙健

    2013-01-01

    The exiting cutting head rotary mechanism of 3D laser cutting machine has been illustrated and compared.A rotary mechanism based on composite drive technology has been designed,which provides reference for the R&D of the 3D & 5-axis laser cutting machine.%对现有三维激光切割机的激光头旋转机构进行了介绍和比较,设计了一种基于复合驱动技术的激光头旋转机构,可为三维五轴激光切割机的研发提供参考.

  11. 三维激光扫描技术曲面拟合方法研究%3 dLaser Scanning Technology Surface Fitting Method

    Institute of Scientific and Technical Information of China (English)

    曹奇; 岳东杰; 杨畅

    2014-01-01

    Point cloud data processing and point cloud of curved surface and curve fitting in reverse engineering is an important re -search topic .Reverse engineering is an important task to actual physical model reconstruction , but the geometric models generated from the core problem is how to reconstruct the sampling point curve and surface model .C++development platform and MATLAB based on 3D laser scanning data using B -spline, NURBS, triangular mesh surface method and the curve fitting method of research and exploration .%点云数据处理以及点云的曲面、曲线拟合是逆向工程中一个重要的研究课题,其重要任务就是将实际物理模型重建生成几何模型,而核心问题就是如何从采样点出发重建曲线、曲面模型。本文以C++开发平台和MATLAB为基础,对三维激光扫描数据利用B样条、NURBS、三角网格曲面拟合方法和曲线拟合方法进行研究探索。

  12. Laser beam melting 3D printing of Ti6Al4V based porous structured dental implants: fabrication, biocompatibility analysis and photoelastic study

    Science.gov (United States)

    Yang, Fei; Chen, Chen; Zhou, QianRong; Gong, YiMing; Li, RuiXue; Li, ChiChi; Klämpfl, Florian; Freund, Sebastian; Wu, XingWen; Sun, Yang; Li, Xiang; Schmidt, Michael; Ma, Duan; Yu, YouCheng

    2017-01-01

    Fabricating Ti alloy based dental implants with defined porous scaffold structure is a promising strategy for improving the osteoinduction of implants. In this study, we use Laser Beam Melting (LBM) 3D printing technique to fabricate porous Ti6Al4V dental implant prototypes with three controlled pore sizes (200, 350 and 500 μm). The mechanical stress distribution in the surrounding bone tissue is characterized by photoelastography and associated finite element simulation. For in-vitro studies, experiments on implants’ biocompatibility and osteogenic capability are conducted to evaluate the cellular response correlated to the porous structure. As the preliminary results, porous structured implants show a lower stress-shielding to the surrounding bone at the implant neck and a more densed distribution at the bottom site compared to the reference implant. From the cell proliferation tests and the immunofluorescence images, 350 and 500 μm pore sized implants demonstrate a better biocompatibility in terms of cell growth, migration and adhesion. Osteogenic genes expression of the 350 μm group is significantly increased alone with the ALP activity test. All these suggest that a pore size of 350 μm provides an optimal provides an optimal potential for improving the mechanical shielding to the surrounding bones and osteoinduction of the implant itself. PMID:28350007

  13. Laser beam melting 3D printing of Ti6Al4V based porous structured dental implants: fabrication, biocompatibility analysis and photoelastic study.

    Science.gov (United States)

    Yang, Fei; Chen, Chen; Zhou, QianRong; Gong, YiMing; Li, RuiXue; Li, ChiChi; Klämpfl, Florian; Freund, Sebastian; Wu, XingWen; Sun, Yang; Li, Xiang; Schmidt, Michael; Ma, Duan; Yu, YouCheng

    2017-03-28

    Fabricating Ti alloy based dental implants with defined porous scaffold structure is a promising strategy for improving the osteoinduction of implants. In this study, we use Laser Beam Melting (LBM) 3D printing technique to fabricate porous Ti6Al4V dental implant prototypes with three controlled pore sizes (200, 350 and 500 μm). The mechanical stress distribution in the surrounding bone tissue is characterized by photoelastography and associated finite element simulation. For in-vitro studies, experiments on implants' biocompatibility and osteogenic capability are conducted to evaluate the cellular response correlated to the porous structure. As the preliminary results, porous structured implants show a lower stress-shielding to the surrounding bone at the implant neck and a more densed distribution at the bottom site compared to the reference implant. From the cell proliferation tests and the immunofluorescence images, 350 and 500 μm pore sized implants demonstrate a better biocompatibility in terms of cell growth, migration and adhesion. Osteogenic genes expression of the 350 μm group is significantly increased alone with the ALP activity test. All these suggest that a pore size of 350 μm provides an optimal provides an optimal potential for improving the mechanical shielding to the surrounding bones and osteoinduction of the implant itself.

  14. Laser beam melting 3D printing of Ti6Al4V based porous structured dental implants: fabrication, biocompatibility analysis and photoelastic study

    Science.gov (United States)

    Yang, Fei; Chen, Chen; Zhou, Qianrong; Gong, Yiming; Li, Ruixue; Li, Chichi; Klämpfl, Florian; Freund, Sebastian; Wu, Xingwen; Sun, Yang; Li, Xiang; Schmidt, Michael; Ma, Duan; Yu, Youcheng

    2017-03-01

    Fabricating Ti alloy based dental implants with defined porous scaffold structure is a promising strategy for improving the osteoinduction of implants. In this study, we use Laser Beam Melting (LBM) 3D printing technique to fabricate porous Ti6Al4V dental implant prototypes with three controlled pore sizes (200, 350 and 500 μm). The mechanical stress distribution in the surrounding bone tissue is characterized by photoelastography and associated finite element simulation. For in-vitro studies, experiments on implants’ biocompatibility and osteogenic capability are conducted to evaluate the cellular response correlated to the porous structure. As the preliminary results, porous structured implants show a lower stress-shielding to the surrounding bone at the implant neck and a more densed distribution at the bottom site compared to the reference implant. From the cell proliferation tests and the immunofluorescence images, 350 and 500 μm pore sized implants demonstrate a better biocompatibility in terms of cell growth, migration and adhesion. Osteogenic genes expression of the 350 μm group is significantly increased alone with the ALP activity test. All these suggest that a pore size of 350 μm provides an optimal provides an optimal potential for improving the mechanical shielding to the surrounding bones and osteoinduction of the implant itself.

  15. Laser-ignited frontal polymerization of shape-controllable poly(VI-co-AM) hydrogels based on 3D templates toward adsorption of heavy metal ions

    Science.gov (United States)

    Fan, Suzhen; Liu, Sisi; Wang, Xiao-Qiao; Wang, Cai-Feng; Chen, Su

    2016-06-01

    Given the increasing heavy metal pollution issue, fast preparation of polymeric hydrogels with excellent adsorption property toward heavy metal ions is very attractive. In this work, a series of poly( N-vinylimidazole-co-acrylamide) (poly(VI-co-AM)) hydrogels were synthesized via laser-ignited frontal polymerization (LIFP) for the first time. The dependence of frontal velocity and temperature on two factors monomer ratios and initiator concentrations was systematically investigated. Poly(VI-co-AM) hydrogels with any self-supporting shapes can be synthesized by a one-step LIFP in seconds through the application of 3D templates. These shape-persistent hydrogels are pH-responsive and exhibit excellent adsorption/desorption characteristics toward Mn(II), Zn(II), Cd(II), Ni(II), Cu(II) and Co(II) ions, and the adsorption conformed to the pseudo-second-order kinetic model. The reusability of the hydrogels toward mental ions adsorption was further researched, which suggested that the hydrogels can be reused without serious decrease in adsorption capacity. This work might open a promising strategy to facilely prepare shape-controllable hydrogels and expand the application of LIFP.

  16. Web-based interactive visualization of 3D video mosaics using X3D standard

    Institute of Scientific and Technical Information of China (English)

    CHON Jaechoon; LEE Yang-Won; SHIBASAKI Ryosuke

    2006-01-01

    We present a method of 3D image mosaicing for real 3D representation of roadside buildings, and implement a Web-based interactive visualization environment for the 3D video mosaics created by 3D image mosaicing. The 3D image mosaicing technique developed in our previous work is a very powerful method for creating textured 3D-GIS data without excessive data processing like the laser or stereo system. For the Web-based open access to the 3D video mosaics, we build an interactive visualization environment using X3D, the emerging standard of Web 3D. We conduct the data preprocessing for 3D video mosaics and the X3D modeling for textured 3D data. The data preprocessing includes the conversion of each frame of 3D video mosaics into concatenated image files that can be hyperlinked on the Web. The X3D modeling handles the representation of concatenated images using necessary X3D nodes. By employing X3D as the data format for 3D image mosaics, the real 3D representation of roadside buildings is extended to the Web and mobile service systems.

  17. The Area of a Polygon with an Inscribed Circle

    CERN Document Server

    Buck, Marshall W

    2012-01-01

    Heron's formula states that the area $K$ of a triangle with sides $a$, $b$, and $c$ is given by $$ K=\\sqrt {s(s-a) (s-b) (s-c)} $$ where $s$ is the semiperimeter $(a+b+c)/2$. Brahmagupta, Robbins, Roskies, and Maley generalized this formula for polygons of up to eight sides inscribed in a circle. In this paper we derive formulas giving the areas of any $n$-gon, with odd $n$, in terms of the ordered list of side lengths, if the $n$-gon is circumscribed about a circle (instead of being inscribed in a circle). Unlike the cyclic polygon problem, where the order of the sides does not matter, for the inscribed circle problem (our case) it does matter. The solution is much easier than for the cyclic polygon problem, but it does generalize easily to all odd $n$. We also provide necessary and sufficient conditions for there to be solutions in the case of even $n$.

  18. Comparison of 3D laser-based photonic scans and manual anthropometric measurements of body size and shape in a validation study of 123 young Swiss men

    Directory of Open Access Journals (Sweden)

    Nikola Koepke

    2017-02-01

    Full Text Available Background Manual anthropometric measurements are time-consuming and challenging to perform within acceptable intra- and inter-individual error margins in large studies. Three-dimensional (3D laser body scanners provide a fast and precise alternative: within a few seconds the system produces a 3D image of the body topography and calculates some 150 standardised body size measurements. Objective The aim was to enhance the small number of existing validation studies and compare scan and manual techniques based on five selected measurements. We assessed the agreement between two repeated measurements within the two methods, analysed the direct agreement between the two methods, and explored the differences between the techniques when used in regressions assessing the effect of health related determinants on body shape indices. Methods We performed two repeated body scans on 123 volunteering young men using a Vitus Smart XXL body scanner. We manually measured height, waist, hip, buttock, and chest circumferences twice for each participant according to the WHO guidelines. The participants also filled in a basic questionnaire. Results Mean differences between the two scan measurements were smaller than between the two manual measurements, and precision as well as intra-class correlation coefficients were higher. Both techniques were strongly correlated. When comparing means between both techniques we found significant differences: Height was systematically shorter by 2.1 cm, whereas waist, hip and bust circumference measurements were larger in the scans by 1.17–4.37 cm. In consequence, body shape indices also became larger and the prevalence of overweight was greater when calculated from the scans. Between 4.1% and 7.3% of the probands changed risk category from normal to overweight when classified based on the scans. However, when employing regression analyses the two measurement techniques resulted in very similar coefficients, confidence

  19. Comparison of 3D laser-based photonic scans and manual anthropometric measurements of body size and shape in a validation study of 123 young Swiss men

    Science.gov (United States)

    Zwahlen, Marcel; Wells, Jonathan C.; Bender, Nicole; Henneberg, Maciej

    2017-01-01

    Background Manual anthropometric measurements are time-consuming and challenging to perform within acceptable intra- and inter-individual error margins in large studies. Three-dimensional (3D) laser body scanners provide a fast and precise alternative: within a few seconds the system produces a 3D image of the body topography and calculates some 150 standardised body size measurements. Objective The aim was to enhance the small number of existing validation studies and compare scan and manual techniques based on five selected measurements. We assessed the agreement between two repeated measurements within the two methods, analysed the direct agreement between the two methods, and explored the differences between the techniques when used in regressions assessing the effect of health related determinants on body shape indices. Methods We performed two repeated body scans on 123 volunteering young men using a Vitus Smart XXL body scanner. We manually measured height, waist, hip, buttock, and chest circumferences twice for each participant according to the WHO guidelines. The participants also filled in a basic questionnaire. Results Mean differences between the two scan measurements were smaller than between the two manual measurements, and precision as well as intra-class correlation coefficients were higher. Both techniques were strongly correlated. When comparing means between both techniques we found significant differences: Height was systematically shorter by 2.1 cm, whereas waist, hip and bust circumference measurements were larger in the scans by 1.17–4.37 cm. In consequence, body shape indices also became larger and the prevalence of overweight was greater when calculated from the scans. Between 4.1% and 7.3% of the probands changed risk category from normal to overweight when classified based on the scans. However, when employing regression analyses the two measurement techniques resulted in very similar coefficients, confidence intervals, and p

  20. IZDELAVA TISKALNIKA 3D

    OpenAIRE

    Brdnik, Lovro

    2015-01-01

    Diplomsko delo analizira trenutno stanje 3D tiskalnikov na trgu. Prikazan je razvoj in principi delovanja 3D tiskalnikov. Predstavljeni so tipi 3D tiskalnikov, njihove prednosti in slabosti. Podrobneje je predstavljena zgradba in delovanje koračnih motorjev. Opravljene so meritve koračnih motorjev. Opisana je programska oprema za rokovanje s 3D tiskalniki in komponente, ki jih potrebujemo za izdelavo. Diploma se oklepa vprašanja, ali je izdelava 3D tiskalnika bolj ekonomična kot pa naložba v ...

  1. 三维激光扫描技术在土石方量测量中的应用%Application of 3D laser scanning technology to the earthwork calculation

    Institute of Scientific and Technical Information of China (English)

    袁凤祥; 秦岩宾; 安家瑞

    2016-01-01

    This paper introduces the theory of the 3D laser scanner,the method of earth volume calculation, and the basic flow of measuring earth volume by 3D laser scanning technology.Combined with examples, illustrations are made on measuring a small ore heap by 3D laser scanning technology in the Town of Chujiang,Dayi County,Sichuan Province.The results show that 3D laser scanning technology enjoys high superiority over the traditional method of measuring the earth volume.%简要介绍三维激光扫描仪的工作原理,测量土石方量的基本步骤及土石方量计算的基本原理。结合四川省大邑县出江镇矿堆测量实例,计算出土石方量。结果表明,相对于传统测量方法,三维激光扫描技术更具优势。

  2. 3D and Education

    Science.gov (United States)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  3. 新型三维激光扫描系统曲面重构技术%Surface reconstruction techniques for a novel 3D laser scanning system

    Institute of Scientific and Technical Information of China (English)

    王文标; 吴德烽; 马孜; 李爱国; 汪洋

    2011-01-01

    The existed reverse engineering equipments are expensive and of low speed, a novel 3D laser free surface scanning system was developed, which had fast scanning speed and of low cost.As for the surface reconstruction part in the proposed system, two surface reconstruction schemes were presented based on two types of artificial neural network, namely, radial basis function neural network (RBFNN)and multiperceptron layer neural network (MLPNN).The X and Y coordinates of point cloud data were chosen as network input while the Z coordinate was chosen as network output.Comparison is made between these two approaches.Experimental results demonstrate that the accuracy of RBFNN for scattered point cloud surface reconstruction is higher than MLPNN.However, more neurons in hidden layer are needed for RBFNN than MLPNN.%为了克服现有逆向工程装备价格昂贵且不能满足实时测量的缺点,提出了一种新型成本低、扫描速度快的三维激光自由曲面扫描系统.针对该系统的曲面重构问题,提出神经网络曲面重构方案,网络的输入选取所获得的点云数据的X、Y坐标,网络的输出则选取点云数据的Z坐标.比较了径向基神经网络(RBFNN)和多层前馈神经网络(MLPNN)两种典型神经网络曲面重构方案的优缺点.实验结果表明:RBFNN对于离散点云的曲面重构精度比MLPNN重构的精度高,但RBFNN较MLPNN 所需的隐层神经元个数多.

  4. Nonlaser-based 3D surface imaging

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shin-yee; Johnson, R.K.; Sherwood, R.J. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    3D surface imaging refers to methods that generate a 3D surface representation of objects of a scene under viewing. Laser-based 3D surface imaging systems are commonly used in manufacturing, robotics and biomedical research. Although laser-based systems provide satisfactory solutions for most applications, there are situations where non laser-based approaches are preferred. The issues that make alternative methods sometimes more attractive are: (1) real-time data capturing, (2) eye-safety, (3) portability, and (4) work distance. The focus of this presentation is on generating a 3D surface from multiple 2D projected images using CCD cameras, without a laser light source. Two methods are presented: stereo vision and depth-from-focus. Their applications are described.

  5. TEHNOLOGIJE 3D TISKALNIKOV

    OpenAIRE

    Kolar, Nataša

    2016-01-01

    Diplomsko delo predstavi razvoj tiskanja skozi čas. Podrobneje so opisani 3D tiskalniki, ki uporabljajo različne tehnologije 3D tiskanja. Predstavljene so različne tehnologije 3D tiskanja, njihova uporaba in narejeni prototipi oz. končni izdelki. Diplomsko delo opiše celoten postopek, od zamisli, priprave podatkov in tiskalnika do izdelave prototipa oz. končnega izdelka.

  6. Fiber optic anemometer based on metal infiltrated microstructured optical fiber inscribed with Bragg grating

    Science.gov (United States)

    Wang, Jie; Gao, Shaorui; Liu, Zhengyong; Zhang, A. Ping; Shen, Yonghang; Tam, Hwayaw

    2015-09-01

    An all-fiber optical anemometer with high light-heat conversion efficiency by using an in-house microstructured optical fiber Bragg grating (MOFBG) is presented. Low-molten-temperature BiSnIn alloy was successfully infiltrated into 11- cm length of a six-hole microstructured optical fiber which was inscribed with a fibre Bragg grating (FBG) centered at ~848 nm. Light launched into the MOFBG was strongly absorbed by the metal to generate heat, while the FBG was utilized to monitor temperature change due to surrounding wind speed. The sensitivity of the laser-heated MOFBG anemometer was measured to be ~0.1 nm/(m/s) for wind speed ranged from 0.5 m/s to 2 m/s. The efficiency of the anemometer, defined as effective sensitivity per pump power, is 8.7 nm/(m/s*W).

  7. Imaging a Sustainable Future in 3D

    Science.gov (United States)

    Schuhr, W.; Lee, J. D.; Kanngieser, E.

    2012-07-01

    It is the intention of this paper, to contribute to a sustainable future by providing objective object information based on 3D photography as well as promoting 3D photography not only for scientists, but also for amateurs. Due to the presentation of this article by CIPA Task Group 3 on "3D Photographs in Cultural Heritage", the presented samples are masterpieces of historic as well as of current 3D photography concentrating on cultural heritage. In addition to a report on exemplarily access to international archives of 3D photographs, samples for new 3D photographs taken with modern 3D cameras, as well as by means of a ground based high resolution XLITE staff camera and also 3D photographs taken from a captive balloon and the use of civil drone platforms are dealt with. To advise on optimum suited 3D methodology, as well as to catch new trends in 3D, an updated synoptic overview of the 3D visualization technology, even claiming completeness, has been carried out as a result of a systematic survey. In this respect, e.g., today's lasered crystals might be "early bird" products in 3D, which, due to lack in resolution, contrast and color, remember to the stage of the invention of photography.

  8. 基于激光影像的物体三维点云获取系统%The acquisition System of 3D Point Cloud Based on Image With Laser

    Institute of Scientific and Technical Information of China (English)

    王震; 刘进

    2013-01-01

    三维点云获取系统能够快速地获取目标物体的几何信息,生成大量点云,将目标的真实三维形态在计算机中可视化的展现出来。本文提出了一种新的三维点云数据获取的方法,应用在自主开发的基于激光影像的物体三维点云获取系统中,即标定激光面映射目标表面点的一维坐标,利用单像摄影测量后方交会和一维坐标的联合解算,得出目标点三维伪坐标。通过坐标逆向旋转恢复,得到真实的三维坐标数据,据此完整地建立目标物体的三维可视化模型。%The acquisition system of 3D point cloud can get the geometric information fast and provide a lot of point cloud data in order to show the object 3D shape on a computer .This paper gives a new method of getting 3D point cloud data that is applied to the self-made system of object 3D point cloud acquisition based on image with laser .The calibra-ted laser area reflects the one dimension coordinates of object surface .Through the combined calculation of one dimen-sion coordinate and resection of single photogrammetry the original 3D coordinates of object points can be obtained . Through reverse rotation we can get the true 3D coordinates and construct the complete 3D visual model of object.

  9. 3D virtuel udstilling

    DEFF Research Database (Denmark)

    Tournay, Bruno; Rüdiger, Bjarne

    2006-01-01

    3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s.......3d digital model af Arkitektskolens gård med virtuel udstilling af afgangsprojekter fra afgangen sommer 2006. 10 s....

  10. Calibration Error of Robotic Vision System of 3D Laser Scanner%机器人三维激光扫描视觉系统标定误差

    Institute of Scientific and Technical Information of China (English)

    齐立哲; 汤青; 贠超; 王京; 甘中学

    2011-01-01

    The 3D laser scanner is widely applied in industry robot vision system, but the calibration error of positional relationship between the scanner and the robot has important influence on the application of robot vision system. It is presented systematically how the scanning results are influenced by the robotic vision calibration position and orientation errors and how the workpiece positioning process is affected by the scanning result and then it is concluded that the position calibration of vision system is not necessary in the robot workpiece positioning system when there is no variation of robot scanning posture no matter whether the workpiece has posture variation or not. The validity of the theoretical analysis conclusion is verified by tests, thus providing the theoretical basis for explaining the influence of calibration error of vision system on the scanning result and for simplifying the calibration process of the vision system.%基于三维激光扫描仪的工业机器人视觉系统应用越来越广泛,而扫描仪与机器人之间位姿关系标定精度对于机器人视觉系统的应用有重要的影响.介绍基于三维激光扫描仪的机器人视觉系统的相关原理,然后在此基础上系统分析机器人视觉系统位置和姿态标定误差对工件扫描结果和根据扫描结果对工件进行定位过程的影响,得出在工件无姿态变化或有姿态变化但机器人扫描姿态不变情况下的机器人工件定位系统中无须进行视觉系统位置标定的结论,并试验验证了理论分析结论的有效性,为解释视觉系统标定误差对扫描结果的影响情况及简化视觉系统标定过程提供了理论依据.

  11. Reconstruction and analysis of shapes from 3D scans

    NARCIS (Netherlands)

    ter Haar, F.B.

    2009-01-01

    In this thesis we use 3D laser range scans for the acquisition, reconstruction, and analysis of 3D shapes. 3D laser range scanning has proven to be a fast and effective way to capture the surface of an object in a computer. Thousands of depth measurements represent a part of the surface geometry as

  12. Deformation Measurement of 3D Printing Model Based on Laser Speckle Method%基于激光散斑法的模型变形测量研究

    Institute of Scientific and Technical Information of China (English)

    吕纯洁

    2015-01-01

    本文采用激光散斑法测量模型在不同承载状态下的变形数据,并与理论数据进行比较分析,为研究3D打印技术中成品的力学性能提供了实验参考。%It is one of the effective indicators for the performance of 3D printing technology whether or not its products can fully retain inherent mechanics parameters of the materials.A method to measure the deformation of 3D printing models in different load conditions by laser speckle is presented in this paper in comparison with some theoretical data,thus to offer an experimental reference for researches on mechanical property of materials in 3D technology.

  13. Blender 3D cookbook

    CERN Document Server

    Valenza, Enrico

    2015-01-01

    This book is aimed at the professionals that already have good 3D CGI experience with commercial packages and have now decided to try the open source Blender and want to experiment with something more complex than the average tutorials on the web. However, it's also aimed at the intermediate Blender users who simply want to go some steps further.It's taken for granted that you already know how to move inside the Blender interface, that you already have 3D modeling knowledge, and also that of basic 3D modeling and rendering concepts, for example, edge-loops, n-gons, or samples. In any case, it'

  14. Repumping and spectroscopy of laser-cooled Sr atoms using the (5s5p){sup 3}P{sub 2}-(5s4d){sup 3}D{sub 2} transition

    Energy Technology Data Exchange (ETDEWEB)

    Mickelson, P G; De Escobar, Y N Martinez; Anzel, P; DeSalvo, B J; Nagel, S B; Traverso, A J; Yan, M; Killian, T C, E-mail: killian@rice.ed [Department of Physics and Astronomy, Rice University, Houston, TX 77251 (United States)

    2009-12-14

    We describe repumping and spectroscopy of laser-cooled strontium (Sr) atoms using the (5s5p){sup 3}P{sub 2}-(5s4d){sup 3}D{sub 2} transition. Atom number in a magneto-optical trap is enhanced by driving this transition because Sr atoms that have decayed into the (5s5p){sup 3}P{sub 2} dark state are repumped back into the (5s{sup 2}){sup 1}S{sub 0} ground state. Spectroscopy of {sup 84}Sr, {sup 86}Sr, {sup 87}Sr and {sup 88}Sr improves the value of the (5s5p){sup 3}P{sub 2}-(5s4d){sup 3}D{sub 2} transition frequency and determines the isotope shifts for the transition accurately enough to guide laser-cooling experiments with less abundant isotopes.

  15. 3维激光扫描技术在墓葬保护中的应用%The Application of 3D Laser Scanning Technique in Tomb Protection

    Institute of Scientific and Technical Information of China (English)

    韦春桃; 张利恒; 张旭东; 杨海兰

    2012-01-01

    3维扫描技术可以说的是21世纪又一项测绘技术新突破,本文介绍了3维激光扫描技术的工作原理,通过结合实际的墓葬保护工程,重点阐述了3维激光扫描技术数据的采集、处理、建模过程和方法,同时总结3维扫描技术的优点和现阶段存在的问题,为数字考古和文物保护提供新的技术支持。%3D scanning technology is the new breakthrough in Topographic Technique in the 21 st century. This paper introduces the working principle of 3 d laser scanning technology, and it focuses on the 3 d laser scanning techniques of data acquisition, processing, the modeling process and method by combining the actual burial protection engineering, it also summarizes the advantages and the ex- isting problems of 3d scanning technology to provide new technical support for digital archaeology and historic preservation.

  16. 3D Digital Modelling

    DEFF Research Database (Denmark)

    Hundebøl, Jesper

    wave of new building information modelling tools demands further investigation, not least because of industry representatives' somewhat coarse parlance: Now the word is spreading -3D digital modelling is nothing less than a revolution, a shift of paradigm, a new alphabet... Research qeustions. Based...... on empirical probes (interviews, observations, written inscriptions) within the Danish construction industry this paper explores the organizational and managerial dynamics of 3D Digital Modelling. The paper intends to - Illustrate how the network of (non-)human actors engaged in the promotion (and arrest) of 3......D Modelling (in Denmark) stabilizes - Examine how 3D Modelling manifests itself in the early design phases of a construction project with a view to discuss the effects hereof for i.a. the management of the building process. Structure. The paper introduces a few, basic methodological concepts...

  17. DELTA 3D PRINTER

    Directory of Open Access Journals (Sweden)

    ȘOVĂILĂ Florin

    2016-07-01

    Full Text Available 3D printing is a very used process in industry, the generic name being “rapid prototyping”. The essential advantage of a 3D printer is that it allows the designers to produce a prototype in a very short time, which is tested and quickly remodeled, considerably reducing the required time to get from the prototype phase to the final product. At the same time, through this technique we can achieve components with very precise forms, complex pieces that, through classical methods, could have been accomplished only in a large amount of time. In this paper, there are presented the stages of a 3D model execution, also the physical achievement after of a Delta 3D printer after the model.

  18. Using a pulsed laser beam to investigate the feasibility of sub-pixel position resolution with time-correlated transient signals in 3D pixelated CdZnTe detectors

    Science.gov (United States)

    Giraldo, L. Ocampo; Bolotnikov, A. E.; Camarda, G. S.; Cheng, S.; De Geronimo, G.; McGilloway, A.; Fried, J.; Hodges, D.; Hossain, A.; Ünlü, K.; Petryk, M.; Vidal, V.; Vernon, E.; Yang, G.; James, R. B.

    2017-09-01

    We evaluated the X-Y position resolution achievable in 3D pixelated detectors by processing the signal waveforms readout from neighboring pixels. In these measurements we used a focused light beam, down to 10 μm, generated by a 1 mW pulsed laser (650 nm) to carry out raster scans over selected 3×3 pixel areas, while recording the charge signals from the 9 pixels and the cathode using two synchronized digital oscilloscopes.

  19. Professional Papervision3D

    CERN Document Server

    Lively, Michael

    2010-01-01

    Professional Papervision3D describes how Papervision3D works and how real world applications are built, with a clear look at essential topics such as building websites and games, creating virtual tours, and Adobe's Flash 10. Readers learn important techniques through hands-on applications, and build on those skills as the book progresses. The companion website contains all code examples, video step-by-step explanations, and a collada repository.

  20. AE3D

    Energy Technology Data Exchange (ETDEWEB)

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  1. Low-loss waveguides fabricated in BK7 glass by high repetition rate femtosecond fiber laser.

    Science.gov (United States)

    Eaton, Shane M; Ng, Mi Li; Bonse, Jörn; Mermillod-Blondin, Alexandre; Zhang, Haibin; Rosenfeld, Arkadi; Herman, Peter R

    2008-04-20

    For the first time femtosecond-laser writing has inscribed low-loss optical waveguides in Schott BK7 glass, a commercially important type of borosilicate widely used in optical applications. The use of a variable repetition rate laser enabled the identification of a narrow processing window at 1 MHz repetition rate with optimal waveguides exhibiting propagation losses of 0.3 dB/cm and efficient mode matching to standard optical fibers at a 1550 nm wavelength. The waveguides were characterized by complementary phase contrast and optical transmission microscopy, identifying a micrometer-sized guiding region within a larger complex structure of both positive and negative refractive index variations.

  2. Bioresists from renewable resources as sustainable photoresins for 3D laser microlithography: material synthesis, cross-linking rate and characterization of the structures

    Science.gov (United States)

    Skliutas, Edvinas; KašÄ--taitÄ--, Sigita; GrigalevičiÅ«tÄ--, GiedrÄ--; Jonušauskas, Linas; RekštytÄ--, Sima; OstrauskaitÄ--, Jolita; Malinauskas, Mangirdas

    2017-02-01

    Stereolithography (SLA) allows rapid and accurate materialization of computer aided design (CAD) models into real objects out of photoreactive resin. Nowadays this technology has evolved to a widespread simple and flexible personal tabletop devices - three dimensional (3D) optical printers. However, most 3D SLA printers use commercially available resins which are not cheap and of limited applicability, often of unknown chemical ingredients and fixed to certain mechanical properties. For advanced research, it is important to have bio-resin appropriate to 3D print microscaffolds for cell proliferation and tissue engineering. To fill these requirements would be to use sources from bio-based resins, which can be made of naturally derived oils. Chosen substances glycerol diglycidyl ether and epoxidized linseed oil can be obtained from renewable recourses, are biodegradable and can be synthesized as sustainable photosensitive materials.1 UV (ff=365 nm) lithography was employed to determine their photocross-linking rate and cured material properties. After exposing material to UV radiation through a micro-patterned amplitude mask selective photopolymerization was observed. Acetone was used as a solvent to dissolve UV unaffected area and leaving only exposed microstructures on the substrate. The resins were compared to FormLabs Form Clear and Autodesk Ember PR48 as standard stereolithography materials. Finally, 3D microporous woodpile scaffolds were printed out of commercial resins and cells adhesion in them were explored.

  3. 3D Projection Installations

    DEFF Research Database (Denmark)

    Halskov, Kim; Johansen, Stine Liv; Bach Mikkelsen, Michelle

    2014-01-01

    Three-dimensional projection installations are particular kinds of augmented spaces in which a digital 3-D model is projected onto a physical three-dimensional object, thereby fusing the digital content and the physical object. Based on interaction design research and media studies, this article...... contributes to the understanding of the distinctive characteristics of such a new medium, and identifies three strategies for designing 3-D projection installations: establishing space; interplay between the digital and the physical; and transformation of materiality. The principal empirical case, From...... Fingerplan to Loop City, is a 3-D projection installation presenting the history and future of city planning for the Copenhagen area in Denmark. The installation was presented as part of the 12th Architecture Biennale in Venice in 2010....

  4. 3D Spectroscopic Instrumentation

    CERN Document Server

    Bershady, Matthew A

    2009-01-01

    In this Chapter we review the challenges of, and opportunities for, 3D spectroscopy, and how these have lead to new and different approaches to sampling astronomical information. We describe and categorize existing instruments on 4m and 10m telescopes. Our primary focus is on grating-dispersed spectrographs. We discuss how to optimize dispersive elements, such as VPH gratings, to achieve adequate spectral resolution, high throughput, and efficient data packing to maximize spatial sampling for 3D spectroscopy. We review and compare the various coupling methods that make these spectrographs ``3D,'' including fibers, lenslets, slicers, and filtered multi-slits. We also describe Fabry-Perot and spatial-heterodyne interferometers, pointing out their advantages as field-widened systems relative to conventional, grating-dispersed spectrographs. We explore the parameter space all these instruments sample, highlighting regimes open for exploitation. Present instruments provide a foil for future development. We give an...

  5. Radiochromic 3D Detectors

    Science.gov (United States)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  6. Method for Metal Mine Surveying Based on 3D Laser Scanning Technique%基于3D激光扫描的金属矿测量方法研究

    Institute of Scientific and Technical Information of China (English)

    姚吉利; 刘科利; 张磊; 刘守忠

    2011-01-01

    There are many characteristics in 3D laser technology, such as rapid, non-contact, real-time, dynamic,initiative, high-density, high-precision, digital, automation, and so on, so it can be applied in the surface and underground surveying of open-pit. Based on the data of 3 D laser scanner, a high accuracy 3 D model is set up to provide the information for the mine design, mine production and dynamic data management. In addition ,3D laser scan technology can be used to the underground tunnel survey with tunnel models created rapidly. Its spatial relations among tunnels are obtained through the model, providing the comprehensive and high-precision spatial data for digital mine. Lastly, the method for improving the accuracy and the principle of coordinate correction are presented.%激光扫描技术具有快速性,不接触性,实时、动态、主动性,高密度、高精度,数字化、自动化等特性,正好适用于露天矿的地面和地下测量.用露天矿的激光扫描数据,建立了露天采区三维高精度模型,为矿山设计、矿山生产及数据动态管理提供可靠信息,另外把激光扫描技术用于地下巷道进行测量,迅速建立好巷道模型,直观地获取了各巷道之间的空间关系,为"数字矿山"提供全面、高精度数据.提出了提高坐标纠正精度的方法和月采矿量的测量原理.

  7. Interaktiv 3D design

    DEFF Research Database (Denmark)

    Villaume, René Domine; Ørstrup, Finn Rude

    2002-01-01

    Projektet undersøger potentialet for interaktiv 3D design via Internettet. Arkitekt Jørn Utzons projekt til Espansiva blev udviklet som et byggesystem med det mål, at kunne skabe mangfoldige planmuligheder og mangfoldige facade- og rumudformninger. Systemets bygningskomponenter er digitaliseret som...... 3D elementer og gjort tilgængelige. Via Internettet er det nu muligt at sammenstille og afprøve en uendelig  række bygningstyper som  systemet blev tænkt og udviklet til....

  8. Dynamic Investigation of Triangles Inscribed in a Circle, Which Tend to an Equilateral Triangle

    Science.gov (United States)

    Stupel, Moshe; Oxman, Victor; Sigler, Avi

    2017-01-01

    We present a geometrical investigation of the process of creating an infinite sequence of triangles inscribed in a circle, whose areas, perimeters and lengths of radii of the inscribed circles tend to a limit in a monotonous manner. First, using geometrical software, we investigate four theorems that represent interesting geometrical properties,…

  9. Efficient workflows for 3D building full-color model reconstruction using LIDAR long-range laser and image-based modeling techniques

    Science.gov (United States)

    Shih, Chihhsiong

    2005-01-01

    Two efficient workflow are developed for the reconstruction of a 3D full color building model. One uses a point wise sensing device to sample an unknown object densely and attach color textures from a digital camera separately. The other uses an image based approach to reconstruct the model with color texture automatically attached. The point wise sensing device reconstructs the CAD model using a modified best view algorithm that collects the maximum number of construction faces in one view. The partial views of the point clouds data are then glued together using a common face between two consecutive views. Typical overlapping mesh removal and coarsening procedures are adapted to generate a unified 3D mesh shell structure. A post processing step is then taken to combine the digital image content from a separate camera with the 3D mesh shell surfaces. An indirect uv mapping procedure first divide the model faces into groups within which every face share the same normal direction. The corresponding images of these faces in a group is then adjusted using the uv map as a guidance. The final assembled image is then glued back to the 3D mesh to present a full colored building model. The result is a virtual building that can reflect the true dimension and surface material conditions of a real world campus building. The image based modeling procedure uses a commercial photogrammetry package to reconstruct the 3D model. A novel view planning algorithm is developed to guide the photos taking procedure. This algorithm successfully generate a minimum set of view angles. The set of pictures taken at these view angles can guarantee that each model face shows up at least in two of the pictures set and no more than three. The 3D model can then be reconstructed with minimum amount of labor spent in correlating picture pairs. The finished model is compared with the original object in both the topological and dimensional aspects. All the test cases show exact same topology and

  10. 基于三维激光扫描技术的景观石重建技术%The model-based reconstruction based on 3D laser scanning technology

    Institute of Scientific and Technical Information of China (English)

    毛杰; 张西童; 吴珍珍; 李丽雪

    2016-01-01

    T his paper ,taking a school landscape stone 3D laser scanning point cloud as an example ,aims to solve the 3D laser scanning process due to environmental factors and signal interference ,and discusses the point clouds noise problems , point clouds registration , point cloud filtering aspect , and model reconstruction .Based on the model established by point cloud data for image texture mapping study ,it explores and solves the emerging problems in the texture mapping and sums up a collection point cloud data from a 3D model to a realistic modeling method .RiSCAN Pro Geomagic Studio 11 reverse engineering software and 3ds Max software are used to handle and resolve to ultimately realize the 3D surface reconstruction of complex objects .Experimental results show that this method can quickly and accurately process point cloud data to obtain a 3D laser scanning .T he realization of complex 3D surface of the object's rapid visualization model has a certain practicality on reconstruction .%以获取某校景观石的三维激光扫描点云为实例,解决在三维激光扫描过程中由于环境因素、信号干扰等产生点云噪声的问题,并对点云拼接、点云滤波、模型重建等方面进行探讨;对基于点云数据建立的模型进行影像纹理映射的研究,并对在纹理映射中出现的各种问题进行探讨与解决,总结出一种从点云数据的采集到建立具有真实感的三维模型建模方法。使用RiSCAN pro ,Geomagic Stdio 11逆向工程软件以及3ds Max软件进行处理和解决,最终实现了复杂表面物体的三维模型重建。实验结果表明,文中方法能够快速准确地处理三维激光扫描仪所获取的点云数据,对实现复杂表面物体快速三维可视化模型重建具有一定实用性。

  11. An Axisymmetric Numerical Model for Simulating Kinetically-Limited Growth of a Cylindrical Rod in 3D Laser-induced Chemical Vapor Deposition

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Laser-induced chemical vapor deposition (LCVD) is an important process for freeform microfabrication of high aspect ratio prototypes. The system consists of a laser beam focused onto a movable substrate in a vacuum chamber.Heat from the laser at or near the focal spot of the beam causes gas in the chamber to react. As a result, solidphase reaction products are deposited on the substrate to form the microstructure. In this paper, we develop a numerical model for simulating growth of an axisymmetric cylindrical rod by pre-specifying the surface temperatures required for growing the rod and then by solving for the laser power that satisfies the pre-specified temperatures.The solution using least squares is obtained by minimizing the sum of square deviations between the pre-specified surface temperatures and the calculated temperatures from the heat equation with a given laser power as a heat source. Model predictions of the laser power over growth time helped in optimizing the growth process. Rods grown based on the predicted laser power from the numerical model were very close to being cylindrical in shape. Ways to further improve the model are being investigated.

  12. 3D Wire 2015

    DEFF Research Database (Denmark)

    Jordi, Moréton; F, Escribano; J. L., Farias

    This document is a general report on the implementation of gamification in 3D Wire 2015 event. As the second gamification experience in this event, we have delved deeply in the previous objectives (attracting public areas less frequented exhibition in previous years and enhance networking) and ha......, improves socialization and networking, improves media impact, improves fun factor and improves encouragement of the production team....

  13. Shaping 3-D boxes

    DEFF Research Database (Denmark)

    Stenholt, Rasmus; Madsen, Claus B.

    2011-01-01

    Enabling users to shape 3-D boxes in immersive virtual environments is a non-trivial problem. In this paper, a new family of techniques for creating rectangular boxes of arbitrary position, orientation, and size is presented and evaluated. These new techniques are based solely on position data...

  14. Tangible 3D Modelling

    DEFF Research Database (Denmark)

    Hejlesen, Aske K.; Ovesen, Nis

    2012-01-01

    This paper presents an experimental approach to teaching 3D modelling techniques in an Industrial Design programme. The approach includes the use of tangible free form models as tools for improving the overall learning. The paper is based on lecturer and student experiences obtained through facil...

  15. Morphometric Optic Nerve Head Analysis in Glaucoma Patients: A Comparison between the Simultaneous Nonmydriatic Stereoscopic Fundus Camera (Kowa Nonmyd WX3D and the Heidelberg Scanning Laser Ophthalmoscope (HRT III

    Directory of Open Access Journals (Sweden)

    Siegfried Mariacher

    2016-01-01

    Full Text Available Purpose. To investigate the agreement between morphometric optic nerve head parameters assessed with the confocal laser ophthalmoscope HRT III and the stereoscopic fundus camera Kowa nonmyd WX3D retrospectively. Methods. Morphometric optic nerve head parameters of 40 eyes of 40 patients with primary open angle glaucoma were analyzed regarding their vertical cup-to-disc-ratio (CDR. Vertical CDR, disc area, cup volume, rim volume, and maximum cup depth were assessed with both devices by one examiner. Mean bias and limits of agreement (95% CI were obtained using scatter plots and Bland-Altman analysis. Results. Overall vertical CDR comparison between HRT III and Kowa nonmyd WX3D measurements showed a mean difference (limits of agreement of −0.06 (−0.36 to 0.24. For the CDR < 0.5 group (n=24 mean difference in vertical CDR was −0.14 (−0.34 to 0.06 and for the CDR ≥ 0.5 group (n=16 0.06 (−0.21 to 0.34. Conclusion. This study showed a good agreement between Kowa nonmyd WX3D and HRT III with regard to widely used optic nerve head parameters in patients with glaucomatous optic neuropathy. However, data from Kowa nonmyd WX3D exhibited the tendency to measure larger CDR values than HRT III in the group with CDR < 0.5 group and lower CDR values in the group with CDR ≥ 0.5.

  16. A Linear Ion Trap with an Expanded Inscribed Diameter to Improve Optical Access for Fluorescence Spectroscopy

    Science.gov (United States)

    Rajagopal, Vaishnavi; Stokes, Chris; Ferzoco, Alessandra

    2017-08-01

    We report a custom-geometry linear ion trap designed for fluorescence spectroscopy of gas-phase ions at ambient to cryogenic temperatures. Laser-induced fluorescence from trapped ions is collected from between the trapping rods, orthogonal to the excitation laser that runs along the axis of the linear ion trap. To increase optical access to the ion cloud, the diameter of the round trapping rods is 80% of the inscribed diameter, rather than the roughly 110% used to approximate purely quadrupolar electric fields. To encompass as much of the ion cloud as possible, the first collection optic has a 25.4 mm diameter and a numerical aperture of 0.6. The choice of geometry and collection optics yields 107 detected photons/s from trapped rhodamine 6G ions. The trap is coupled to a closed-cycle helium refrigerator, which in combination with two 50 Ohm heaters enables temperature control to below 25 K on the rod electrodes. The purpose of the instrument is to broaden the applicability of fluorescence spectroscopy of gas-phase ions to cases where photon emission is a minority relaxation pathway. Such studies are important to understand how the microenvironment of a chromophore influences excited state charge transfer processes. [Figure not available: see fulltext.

  17. Laser-treated stainless steel mini-screw implants: 3D surface roughness, bone-implant contact, and fracture resistance analysis.

    Science.gov (United States)

    Kang, He-Kyong; Chu, Tien-Min; Dechow, Paul; Stewart, Kelton; Kyung, Hee-Moon; Liu, Sean Shih-Yao

    2016-04-01

    This study investigated the biomechanical properties and bone-implant intersurface response of machined and laser surface-treated stainless steel (SS) mini-screw implants (MSIs). Forty-eight 1.3mm in diameter and 6mm long SS MSIs were divided into two groups. The control (machined surface) group received no surface treatment; the laser-treated group received Nd-YAG laser surface treatment. Half in each group was used for examining surface roughness (Sa and Sq), surface texture, and facture resistance. The remaining MSIs were placed in the maxilla of six skeletally mature male beagle dogs in a randomized split-mouth design. A pair with the same surface treatment was placed on the same side and immediately loaded with 200 g nickel-titanium coil springs for 8 weeks. After killing, the bone-implant contact (BIC) for each MSI was calculated using micro computed tomography. Analysis of variance model and two-sample t test were used for statistical analysis with a significance level of P laser-treated group compared with the machined group (P Laser treatment increased surface roughness without compromising fracture resistance. Despite increasing surface roughness, laser treatment did not improve BIC. Overall, it appears that medical grade SS has the potential to be substituted for titanium alloy MSIs. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  18. Algorithm and engineering realization of non-scanning laser 3D imaging system%非扫描激光三维成像系统算法及工程实现

    Institute of Scientific and Technical Information of China (English)

    张颖; 司一冰; 曹昌东; 刘波; 眭晓林

    2015-01-01

    The principle and basic module of non-scanning laser 3D imaging system were firstly introduced,then the processing platform of system signal was constructed based on the FPGA +DSP hardware.The experimental results show that the system can better complete the 3D pseudo color image display.%介绍了非扫描激光三维成像系统的工作原理和基本组成模块,通过采用 FPGA +DSP硬件架构,构建了系统信号处理平台。实验结果表明,系统能够较好地完成图像的三维伪彩色显示。

  19. Research on 3D Reconstruction of Urban Features from Data Based on Vehicle-borne Laser Scanning%基于车载激光扫描数据的城市地物三维重建研究

    Institute of Scientific and Technical Information of China (English)

    戴彬; 钟若飞; 胡竞

    2011-01-01

    Vehicle-borne laser scanning system can obtain the surface information of city buildings, road traffic facilities and tunnels accurately and quickly, it is very suitable for acquiring the 3D space information of urban objects quickly and accurately that 3d reconstruction on the basis of. But point cloud is not the data of GIS or 3D models,so the conversion from huge amounts of discrete points to 3D models can be used also requires a complex process.At present the method of 3D reconstruction based on vehicle-borne laser scanning is mainly dependent on humancomputer interaction or semi-automatic processing, and it is not for the 3d of whole city objects. To solve this problem, this article only offers a method for the 3d reconstruction of point cloud from vehicle-borne laser scanning based on the classification of city objects. The infrastructure of data is colored point cloud that has already been classified. The key is to make full use of the obejcts'characteristics,and then using different 3d modeling strategies based on different objects. Finally using the point cloud data of Sanya city based on the vehicle-borne laser scanning system that is self-developed of the capital normal university as experimental object,the result verifies the feasibility and practicability of the method that this article proposed.%车载激光扫描系统可以精确、快速获取城市建筑物、道路交通设施、隧道等地物的表面信息,非常适用于城市物体三维空间信息的快速精确获取和在此基础上的三维重建.然而点云不是GIS数据,也不是三维模型,要将大量离散的点处理为可使用的三维模型还需要一系列复杂的过程,现阶段针对车载激光点云三维重建的方法还主要依赖于人工交互或半自动化处理,而且没有针对整个城市地物的三维重建方法.针对这一问题,本文仅提供一种基于地物分类的车载激光点云三维重建的方法,数据基础是已分类的彩色点云,

  20. 利用3S技术及三维激光扫描仪进行耕地损毁勘测%3 S Technology and 3 D Laser Scanner is used to Survey Cultivated Land Damaged

    Institute of Scientific and Technical Information of China (English)

    林学艺

    2016-01-01

    3S technology is used to find cultivated land damaged,network RTK survey the range and area of cultivated land damaged, GIS extract the land area and grade before cultivated land damaged,and Maptek I-Site8810 3D laser scanner is used to recreate 3D model of cultivated land damaged with network RTK.%利用RS技术发现耕地损毁,网络RTK测量耕地损毁范围及面积,GIS提取耕地被损毁前的分类面积和等别,以及利用网络RTK配合Maptek I-Site8810三维激光扫描仪重构损毁耕地三维模型。

  1. 车身覆盖件3维激光切割的特殊工艺处理%Special treatment of 3-D laser cutting of auto-body panels

    Institute of Scientific and Technical Information of China (English)

    梅丽芳; 陈根余; 易际明; 刘金武

    2011-01-01

    为了研究车身覆盖件3维激光切割的工艺技术特性,采用3维5轴联动激光切割装备以及自动编程软件PEPS Pentacut分析了车身覆盖件3维激光切割的特殊工艺,提出了切割过程中特殊工艺的处理方法并通过切割试验进行了验证.结果表明,在实际的3维激光切割过程中,针对碰撞问题,通过添加工艺点,调整切割头方向,使其偏离法线方向一个角度便可消除;针对过烧缺陷,通过修改工艺点法线的方向和密集程度、采用脉冲激光或采用空气作为辅助气体等措施可以有效避免;针对变形难题,通过均布夹钳或修改程序等方法可有效解决.兼顾切割质量和效率,应在穿孔、上下坡及转角的轨迹段采用脉冲激光,在平缓轨迹段采用连续激光.采用3维激光切割技术取代传统工艺的修边模和冲孔模进行车身覆盖件的加工,可以大幅度地降低成本,缩短新车型的研发周期,具有良好的经济价值和应用前景.%In order to study the characteristics of 3-D laser cutting technology of auto-body panels, the 3-D five-axis laser cutting equipment and automatic programming software PEPS Pentacut were adopted. The special process technology of 3-D laser cutting auto body panels was analyzed, and the approaches to special processes in cutting process were proposed and were verified by experiment. The results show that in the actual 3-D laser cutting process, the collision can be escaped by adding the processing points, adjust the direction of the cutting head to offset from the normal direction; the over-burnt defect can be avoided by modifying the normal direction and intensive level of processing points, using pulsed laser or adopting air as auxiliary gas and other measures; the deformation problem can by effectively resolved by clamping or modifying the program. Taking into account the cutting quality and efficiency, a pulse laser should be adopted in the trajectory of perforated

  2. 建筑物重建中的三维激光扫描精度分析%The Accuracy Analysis of 3D Laser Scanning in Building Reconstruction

    Institute of Scientific and Technical Information of China (English)

    张亚; 山峰; 王涛

    2015-01-01

    针对三维激光扫描技术在建筑物重建中数据采集、处理方面存在的误差,从三维激光扫描仪测站定向误差、仪器扫描误差、数据拼接误差进行分析,并构建了点位误差模型,为三维激光扫描技术在建筑物的重建中测量成果的精度评定及测量方案的优化设计提供了理论基础。最后以脉冲式三维激光扫描仪为例对建筑物重建进行精度分析。%According to the error of data collection and data processing,when we use 3D laser scanning technology in the process of building reconstruction,the paper mainly aims at analyzing station directional error,instrument scanning errors and data splicing errors of 3D laser scanner,and forms point error model. It provides theoretical foundation for accuracy evaluation in the measuring outcomes and optimized design of the measurement program. Finally,we analyze the accuracy of the reconstruction of building using pulsed laser scanner.

  3. Application of 3D Laser Scanner in Road Final Survey and Precisicion Analysis%三维激光扫描仪在道路竣工测量中的应用

    Institute of Scientific and Technical Information of China (English)

    王星杰

    2012-01-01

    The three-dimensional laser scanner in road final survey application compared with the conventional mode of operation greatly improves the operation efficiency, reduce the amount and intensity of labor and industry. Due to the three-dimensional laser scanner can quickly collect a large amount of point cloud data, virtual reproduction of the surveyed area terrain, compared with the traditional operation method, it has incomparable advantages. It briefly introduces the working principle of 3D laser scanning technology, introduces in detail the 3D laser scanning technology in road final survey in indoor and field work method, and the testing of the accuracy, of three laser scanning technology in he related engineering application provides a very good reference.%三维激光扫描仪在道路竣工测量中的应用相对于常规作业方式极大地提高了作业效率,降低了外业劳动量和劳动强度。由于三维激光扫描仪能够迅速采集大量的点云数据,实景再现了测区的地形地势,相对于传统的作业方法具有无法比拟的优势。全文概略介绍了三维激光扫描技术的工作原理,详细介绍了三维激光扫描技术在道路竣工测量中的内外业作业方法,同时进行了多方面的精度检验,为三维激光扫描技术在其他相关工程中应用的提供了很好的借鉴作用。

  4. Low-loss 3D-laser-written mid-infrared LiNbO3 depressed-index cladding waveguides for both TE and TM polarizations.

    Science.gov (United States)

    Nguyen, Huu-Dat; Ródenas, Airán; Vázquez de Aldana, Javier R; Martín, Guillermo; Martínez, Javier; Aguiló, Magdalena; Pujol, Maria Cinta; Díaz, Francesc

    2017-02-20

    We report mid-infrared LiNbO3 depressed-index microstructured cladding waveguides fabricated by three-dimensional laser writing showing low propagation losses (~1.5 dB/cm) at 3.68 µm wavelength for both the transverse electric and magnetic polarized modes, a feature previously unachieved due to the strong anisotropic properties of this type of laser microstructured waveguides and which is of fundamental importance for many photonic applications. Using a heuristic modeling-testing iteration design approach which takes into account cladding induced stress-optic index changes, the fabricated cladding microstructure provides low-loss single mode operation for the mid-IR for both orthogonal polarizations. The dependence of the localized refractive index changes within the cladding microstructure with post-fabrication thermal annealing processes was also investigated, revealing its complex dependence of the laser induced refractive index changes on laser fabrication conditions and thermal post-processing steps. The waveguide modes properties and their dependence on thermal post-processing were numerically modeled and fitted to the experimental values by systematically varying three fundamental parameters of this type of waveguides: depressed refractive index values at sub-micron laser-written tracks, track size changes, and piezo-optic induced refractive index changes.

  5. Unoriented 3d TFTs

    CERN Document Server

    Bhardwaj, Lakshya

    2016-01-01

    This paper generalizes two facts about oriented 3d TFTs to the unoriented case. On one hand, it is known that oriented 3d TFTs having a topological boundary condition admit a state-sum construction known as the Turaev-Viro construction. This is related to the string-net construction of fermionic phases of matter. We show how Turaev-Viro construction can be generalized to unoriented 3d TFTs. On the other hand, it is known that the "fermionic" versions of oriented TFTs, known as Spin-TFTs, can be constructed in terms of "shadow" TFTs which are ordinary oriented TFTs with an anomalous Z_2 1-form symmetry. We generalize this correspondence to Pin+ TFTs by showing that they can be constructed in terms of ordinary unoriented TFTs with anomalous Z_2 1-form symmetry having a mixed anomaly with time-reversal symmetry. The corresponding Pin+ TFT does not have any anomaly for time-reversal symmetry however and hence it can be unambiguously defined on a non-orientable manifold. In case a Pin+ TFT admits a topological bou...

  6. Data Integration Acquired from Micro-Uav and Terrestrial Laser Scanner for the 3d Mapping of Jesuit Ruins of São Miguel das Missões

    Science.gov (United States)

    Reiss, M. L. L.; da Rocha, R. S.; Ferraz, R. S.; Cruz, V. C.; Morador, L. Q.; Yamawaki, M. K.; Rodrigues, E. L. S.; Cole, J. O.; Mezzomo, W.

    2016-06-01

    The Jesuit Missions the Guaranis were one of the great examples of cultural, social, and scientific of the eighteenth century, which had its decline from successive wars that followed the exchange of territories domain occupied by Portugal and Spain with the Madrid Treaty of January 13, 1750. One of the great examples of this development is materialized in the ruins of 30 churches and villages that remain in a territory that now comprises part of Brazil, Argentina and Paraguay. These Churches, São Miguel das Missões is among the Brazilian ruins, the best preserved. The ruins of São Miguel das Missões were declared a UNESCO World Cultural Heritage in 1983 and the Institute of National Historical Heritage (IPHAN) is the Brazilian Federal agency that manages and maintains this heritage. In order to produce a geographic database to assist the IPHAN in the management of the Ruins of São Miguel das Missões it was proposed a three-dimensional mapping of these ruins never performed in this location before. The proposal is integrated data acquired from multiple sensors: two micro-UAV, an Asctec Falcon 8 (rotary wing) and a Sensefly e-Bee (fixed wing); photos from terrestrial cameras; two terrestrial LIDAR sensors, one Faro Focus 3D S-120 and Optec 3D-HD ILRIS. With this abundance of sensors has been possible to perform comparisons and integration of the acquired data, and produce a 3D reconstruction of the church with high completeness and accuracy (better than 25 mm), as can be seen in the presentation of this work.

  7. DATA INTEGRATION ACQUIRED FROM MICRO-UAV AND TERRESTRIAL LASER SCANNER FOR THE 3D MAPPING OF JESUIT RUINS OF SÃO MIGUEL DAS MISSÕES

    Directory of Open Access Journals (Sweden)

    M. L. L. Reiss

    2016-06-01

    Full Text Available The Jesuit Missions the Guaranis were one of the great examples of cultural, social, and scientific of the eighteenth century, which had its decline from successive wars that followed the exchange of territories domain occupied by Portugal and Spain with the Madrid Treaty of January 13, 1750. One of the great examples of this development is materialized in the ruins of 30 churches and villages that remain in a territory that now comprises part of Brazil, Argentina and Paraguay. These Churches, São Miguel das Missões is among the Brazilian ruins, the best preserved. The ruins of São Miguel das Missões were declared a UNESCO World Cultural Heritage in 1983 and the Institute of National Historical Heritage (IPHAN is the Brazilian Federal agency that manages and maintains this heritage. In order to produce a geographic database to assist the IPHAN in the management of the Ruins of São Miguel das Missões it was proposed a three-dimensional mapping of these ruins never performed in this location before. The proposal is integrated data acquired from multiple sensors: two micro-UAV, an Asctec Falcon 8 (rotary wing and a Sensefly e-Bee (fixed wing; photos from terrestrial cameras; two terrestrial LIDAR sensors, one Faro Focus 3D S-120 and Optec 3D-HD ILRIS. With this abundance of sensors has been possible to perform comparisons and integration of the acquired data, and produce a 3D reconstruction of the church with high completeness and accuracy (better than 25 mm, as can be seen in the presentation of this work.

  8. Research on application of 3D laser scanner in ancient architecture mapping%三维激光扫描仪在古建筑测绘中的应用研究

    Institute of Scientific and Technical Information of China (English)

    张远翼; 张鹰; 陈晓娟

    2014-01-01

    根据古建筑测绘的特点以及传统测绘方式的不足,在介绍三维激光扫描仪测量原理的基础上,结合三维激光扫描仪在古建筑测绘的优势,以福建武夷山市城村赵氏家祠为例,从古建筑数据的采集、测绘数据的处理到CAD测绘图纸的生成研究三维激光扫描仪在古建筑测绘实践中的实际应用效果。针对三维激光扫描仪测绘过程中庞大的数据量以及Cyclone软件缺陷问题,提出了“分组处理、整合拼接”的应对策略。%On the basis of the characteristics of ancient architecture mapping and the deficiency of traditional survey methods ,this paper introduces the measuring principle of 3D laser scanner at first. Then ,combined with the advantages of 3D laser scanner in ancient architecture mapping ,taking the “Zhao Ancestral Hall”which is an ancient building in Wuyishan City of Fujian Province as an example ,this paper studies the practical application effect of 3D laser scanner used in ancient architecture mapping ,from the collection of ancient architecture mapping data and mapping data processing to the generation of CAD drawings of surveying and mapping. Finally ,aiming at the technical problems of a large number of data generated in the application process and the software defects of Cyclone ,this paper puts forward a specific coping strategy which is “packet processing ,integ rated splice .”

  9. The Application Research of Terrestrial 3 D Laser Scanner for Special Landforms Mapping%三维激光扫描仪在特殊地貌测量中的应用研究

    Institute of Scientific and Technical Information of China (English)

    海青; 沈忱

    2016-01-01

    As a non-contact data collecting instrument, terrestrial 3D laser scanner can be applied in special landform mapping and be broad prospects.The paper elaborates principle of special landform mapping and method of data merging and matching in the spe-cial landform mapping.The accuracy of result is compared in Height and Coordinate between terrestrial 3D laser scanner and total sta-tion.It proves that special landform mapping can be completed and expressed real topography with high accuracy and quick speed by terrestrial 3D laser scanner.A new technic is provided for large-scale mapping of special landform area.%三维激光扫描仪作为一种非接触数据采集设备,在特殊地貌的大比例尺地形测绘中有着广泛的应用前景。本文以草原石城景区为例,阐述了三维激光扫描仪在这种特殊地貌测绘中的应用原理,数据拼接和配准的方法,并与全站仪全野外数字采集的成果进行了高程和平面坐标的比对,证明了使用三维激光扫描仪测绘特殊地貌精度高、速度快,地貌表达逼真,为特殊地貌区域的大比例尺地形图测绘提供了新的技术手段。

  10. 3D silicon strip detectors

    Energy Technology Data Exchange (ETDEWEB)

    Parzefall, Ulrich [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)], E-mail: ulrich.parzefall@physik.uni-freiburg.de; Bates, Richard [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Boscardin, Maurizio [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Dalla Betta, Gian-Franco [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Eckert, Simon [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Eklund, Lars; Fleta, Celeste [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Jakobs, Karl; Kuehn, Susanne [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Lozano, Manuel [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pahn, Gregor [Physikalisches Institut, Universitaet Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany); Parkes, Chris [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Pellegrini, Giulio [Instituto de Microelectronica de Barcelona, IMB-CNM, CSIC, Barcelona (Spain); Pennicard, David [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Piemonte, Claudio; Ronchin, Sabina [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy); Szumlak, Tomasz [University of Glasgow, Department of Physics and Astronomy, Glasgow G12 8QQ (United Kingdom); Zoboli, Andrea [INFN and Universita' di Trento, via Sommarive 14, 38050 Povo di Trento (Italy); Zorzi, Nicola [FBK-irst, Center for Materials and Microsystems, via Sommarive 18, 38050 Povo di Trento (Italy)

    2009-06-01

    While the Large Hadron Collider (LHC) at CERN has started operation in autumn 2008, plans for a luminosity upgrade to the Super-LHC (sLHC) have already been developed for several years. This projected luminosity increase by an order of magnitude gives rise to a challenging radiation environment for tracking detectors at the LHC experiments. Significant improvements in radiation hardness are required with respect to the LHC. Using a strawman layout for the new tracker of the ATLAS experiment as an example, silicon strip detectors (SSDs) with short strips of 2-3 cm length are foreseen to cover the region from 28 to 60 cm distance to the beam. These SSD will be exposed to radiation levels up to 10{sup 15}N{sub eq}/cm{sup 2}, which makes radiation resistance a major concern for the upgraded ATLAS tracker. Several approaches to increasing the radiation hardness of silicon detectors exist. In this article, it is proposed to combine the radiation hard 3D-design originally conceived for pixel-style applications with the benefits of the established planar technology for strip detectors by using SSDs that have regularly spaced doped columns extending into the silicon bulk under the detector strips. The first 3D SSDs to become available for testing were made in the Single Type Column (STC) design, a technological simplification of the original 3D design. With such 3D SSDs, a small number of prototype sLHC detector modules with LHC-speed front-end electronics as used in the semiconductor tracking systems of present LHC experiments were built. Modules were tested before and after irradiation to fluences of 10{sup 15}N{sub eq}/cm{sup 2}. The tests were performed with three systems: a highly focused IR-laser with 5{mu}m spot size to make position-resolved scans of the charge collection efficiency, an Sr{sup 90}{beta}-source set-up to measure the signal levels for a minimum ionizing particle (MIP), and a beam test with 180 GeV pions at CERN. This article gives a brief overview of

  11. Full 3D modelling of pulse propagation enables efficient nonlinear frequency conversion with low energy laser pulses in a single-element tripler

    Science.gov (United States)

    Kardaś, Tomasz M.; Nejbauer, Michał; Wnuk, Paweł; Resan, Bojan; Radzewicz, Czesław; Wasylczyk, Piotr

    2017-01-01

    Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media. PMID:28225007

  12. Full 3D modelling of pulse propagation enables efficient nonlinear frequency conversion with low energy laser pulses in a single-element tripler.

    Science.gov (United States)

    Kardaś, Tomasz M; Nejbauer, Michał; Wnuk, Paweł; Resan, Bojan; Radzewicz, Czesław; Wasylczyk, Piotr

    2017-02-22

    Although new optical materials continue to open up access to more and more wavelength bands where femtosecond laser pulses can be generated, light frequency conversion techniques are still indispensable in filling the gaps on the ultrafast spectral scale. With high repetition rate, low pulse energy laser sources (oscillators) tight focusing is necessary for a robust wave mixing and the efficiency of broadband nonlinear conversion is limited by diffraction as well as spatial and temporal walk-off. Here we demonstrate a miniature third harmonic generator (tripler) with conversion efficiency exceeding 30%, producing 246 fs UV pulses via cascaded second order processes within a single laser beam focus. Designing this highly efficient and ultra compact frequency converter was made possible by full 3-dimentional modelling of propagation of tightly focused, broadband light fields in nonlinear and birefringent media.

  13. Optimized evaluation of a pulsed 2.09 microns holmium:YAG laser impact on the rat brain and 3 D-histomorphometry of the collateral damage.

    Science.gov (United States)

    Ludwig, H C; Bauer, C; Fuhrberg, P; Teichmann, H H; Birbilis, T; Markakis, E

    1998-12-01

    Since more than 20 years CO2 and Nd:YAG lasers are established in the microsurgery of the nervous system. CO2 lasers can be used handheld, but may be focused on the target area by mirror optics and sideports of the operating microscope's micromanipulator. Nd:YAG lasers have the disadvantage of deep penetration into the brain and provocation of a large collateral damage. The need is for a fibre conducted solid system for surgery in delicate areas as for brain stem surgery. Fibre conduction of near infrared lasers allows better exposure of the target area compared to hollow wave guides or mirror equipment. Fibres can be tapered and modified according to the purpose. The holmium:YAG (Ho:YAG) laser has acquired interest by introducing the system into microsurgery of parenchymal tissue. They have not been proven yet sufficiently for neurosurgical tasks. The effort to minimalize the collateral tissue damage has to be maximalized in the surgery of nervous tissue and functional low redundant brain stem or spinal cord tissue. Volumetric data may be more precise in comparison to depth and width data of the laser lesion even when the different levels of the tissue interaction have to be analyzed for estimation of the real side effects in nervous tissue. We have used 50-800 ml delivered Ho:YAG single pulses in cortical areas of Sprague-Dawley rats and investigated the different lesion zones by volumetric data. The functional lesion zone was detected and measured by immunohistological staining of the heat shock protein HSP 72. For further reduction of the focus area, we have used tapered 400 to 200 microns fibres.

  14. Application of distance-coded reference measuring system on rotary swivel drive of the 3D laser cutting machine%距离编码测量装置在三维激光切割机上的应用

    Institute of Scientific and Technical Information of China (English)

    翟东升; 钟昇; 洪超

    2013-01-01

    The application method of distance-coded reference measuring system on rotary swivel drive of the 3D laser cutting machine has been introduced in the text. The above method and conclusion provide reference for the application of distance-coded reference measuring system on other machine tools.%本文主要介绍带距离编码参考点标记的测量装置在三维激光切割机旋转机构上的应用方法,可为距离编码测量装置的应用提供参考.

  15. APPLYING 3D AFFINE TRANSFORMATION AND LEAST SQUARES MATCHING FOR AIRBORNE LASER SCANNING STRIPS ADJUSTMENT WITHOUT GNSS/IMU TRAJECTORY DATA

    Directory of Open Access Journals (Sweden)

    C. Ressl

    2012-09-01

    Full Text Available In this article we extend our previous work on the topic of ALS strip adjustment without GNSS/IMU trajectory data. Between overlap- ping strip pairs the relative orientation as a 3D affine transformation is estimated by a 3D LSM approach, which uses interpolated 2.5D grid surface models of the strips and the entire strip overlap as one big LSM window. The LSM derived relative orientations of all strip pairs in the block together with their covariance matrices are then used simultaneously as observations in an adjustment following the Gauss-Helmert model. This way the exterior orientation of each strip is computed, which refers to a relative block system. If proper ground control data is given, then an absolute orientation of the block of strips can be computed by a final LSM run. In a small example consisting of 4 strips with ca. 70% overlap the improvement in the relative geometric accuracy is demonstrated by the decreasing óMAD of the height differences from 8.4cm (before to 1.6cm (after the strip adjustment.

  16. Reconstruction and Analysis of Shapes from 3D Scans

    NARCIS (Netherlands)

    Haar, F.B. ter

    2009-01-01

    In this thesis, we measure 3D shapes with the use of 3D laser technology, a recent technology that combines physics, mathematics, and computer science to acquire the surface geometry of 3D shapes in the computer. We use this surface geometry to fully reconstruct real world shapes as computer models,

  17. Measurement of the $^{20-22}$Ne $^3$P$_2$-$^3$D$_3$ transition isotope shift using a single, phase modulated laser beam

    CERN Document Server

    Ohayon, Ben; Ron, Guy

    2016-01-01

    We develop a simple technique to accurately measure frequency differences between far lying resonances in a spectroscopy signal using a single laser. This technique was used to measure the isotope shift of the cooling transition of metastable neon for the result of $1626.264(79)$ MHz. The most accurate determination of this value to date.

  18. 3-D Simulation of the Temperature Field of Laser-Assisted Machining with FEM%激光辅助切削温度场的三维有限元仿真

    Institute of Scientific and Technical Information of China (English)

    王慧艺; 李从心; 阮雪榆

    2001-01-01

    激光加热的温度场受材料物性参数、工件几何形状、激光器功率、光斑形状及移动速度的影响.分析激光辅助立铣淬硬钢的工况,提出简化的计算模型,进而将非稳态传热方程化为稳态的传热控制方程.应用三维有限元法,对激光流动加热45#钢的温度场进行了仿真.经对比不同光斑形状、移动速度、光斑温度对温度场的影响,归纳了激光加热的特点,对激光辅助加工工艺参数的选择提出了建议.%Since the temperature field heated by moving laser is a huge gradient on space and time, it is not able to get a convincing result by experiments. However, it can be reproduced by 3-D simulation technology. Many factors affect the temperature field, like the material properties, geometry shape of a part, laser power, focus shape and moving rate. Based on laser-assisted milling of hardened steel, a simplified calculation model was suggested. Furthermore, the control equation of conduction was changed into static from dynamic. The temperature fields of 45# heated by moving laser was simulated with FEM and the different laser focus shapes, moving rates and temperatures were studied. The features of laser heating were concluded and the machining parameters of laser-assisted machining was suggested.

  19. Hyperfine-structure study of the 3d10 5p 2P3/2 level of neutral copper using pulsed level-crossing spectroscopy at short laser wavelengths

    Science.gov (United States)

    Bengtsson, J.; Larsson, J.; Svanberg, S.; Wahlstrom, C.-G.

    1990-01-01

    A hyperfine-structure study of the strongly perturbed 3d10 5p 2P3/2 state of neutral copper was performed using pulsed level-crossing spectroscopy. Excitation was accomplished at the short wavelength of 202 nm, where intense laser pulses were obtained using frequency tripling of dye laser radiation. For Cu-63, a = 61.7(9) MHz, b = 4.9(7) MHz, and tau = 25,5(10) ns were obtained for the magnetic dipole and the electric quadrupoles interaction constants and the lifetime, respectively. A comparison with theoretical calculations based on the multiconfiguration Hartree-Fock method is made. A discussion of the usefulness of level-crossing, quantum-beat, and radio-frequency techniques for high-resolution spectroscopy at wavelengths in the UV and vacuum-UV region is presented.

  20. 3D and beyond

    Science.gov (United States)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.