Science.gov

Sample records for 3-d time domain

  1. 3D Vectorial Time Domain Computational Integrated Photonics

    SciTech Connect

    Kallman, J S; Bond, T C; Koning, J M; Stowell, M L

    2007-02-16

    The design of integrated photonic structures poses considerable challenges. 3D-Time-Domain design tools are fundamental in enabling technologies such as all-optical logic, photonic bandgap sensors, THz imaging, and fast radiation diagnostics. Such technologies are essential to LLNL and WFO sponsors for a broad range of applications: encryption for communications and surveillance sensors (NSA, NAI and IDIV/PAT); high density optical interconnects for high-performance computing (ASCI); high-bandwidth instrumentation for NIF diagnostics; micro-sensor development for weapon miniaturization within the Stockpile Stewardship and DNT programs; and applications within HSO for CBNP detection devices. While there exist a number of photonics simulation tools on the market, they primarily model devices of interest to the communications industry. We saw the need to extend our previous software to match the Laboratory's unique emerging needs. These include modeling novel material effects (such as those of radiation induced carrier concentrations on refractive index) and device configurations (RadTracker bulk optics with radiation induced details, Optical Logic edge emitting lasers with lateral optical inputs). In addition we foresaw significant advantages to expanding our own internal simulation codes: parallel supercomputing could be incorporated from the start, and the simulation source code would be accessible for modification and extension. This work addressed Engineering's Simulation Technology Focus Area, specifically photonics. Problems addressed from the Engineering roadmap of the time included modeling the Auston switch (an important THz source/receiver), modeling Vertical Cavity Surface Emitting Lasers (VCSELs, which had been envisioned as part of fast radiation sensors), and multi-scale modeling of optical systems (for a variety of applications). We proposed to develop novel techniques to numerically solve the 3D multi-scale propagation problem for both the microchip

  2. Time domain topology optimization of 3D nanophotonic devices

    NASA Astrophysics Data System (ADS)

    Elesin, Y.; Lazarov, B. S.; Jensen, J. S.; Sigmund, O.

    2014-02-01

    We present an efficient parallel topology optimization framework for design of large scale 3D nanophotonic devices. The code shows excellent scalability and is demonstrated for optimization of broadband frequency splitter, waveguide intersection, photonic crystal-based waveguide and nanowire-based waveguide. The obtained results are compared to simplified 2D studies and we demonstrate that 3D topology optimization may lead to significant performance improvements.

  3. 3D time-domain airborne EM modeling for an arbitrarily anisotropic earth

    NASA Astrophysics Data System (ADS)

    Yin, Changchun; Qi, Yanfu; Liu, Yunhe

    2016-08-01

    Time-domain airborne EM data is currently interpreted based on an isotropic model. Sometimes, it can be problematic when working in the region with distinct dipping stratifications. In this paper, we simulate the 3D time-domain airborne EM responses over an arbitrarily anisotropic earth with topography by edge-based finite-element method. Tetrahedral meshes are used to describe the abnormal bodies with complicated shapes. We further adopt the Backward Euler scheme to discretize the time-domain diffusion equation for electric field, obtaining an unconditionally stable linear equations system. We verify the accuracy of our 3D algorithm by comparing with 1D solutions for an anisotropic half-space. Then, we switch attentions to effects of anisotropic media on the strengths and the diffusion patterns of time-domain airborne EM responses. For numerical experiments, we adopt three typical anisotropic models: 1) an anisotropic anomalous body embedded in an isotropic half-space; 2) an isotropic anomalous body embedded in an anisotropic half-space; 3) an anisotropic half-space with topography. The modeling results show that the electric anisotropy of the subsurface media has big effects on both the strengths and the distribution patterns of time-domain airborne EM responses; this effect needs to be taken into account when interpreting ATEM data in areas with distinct anisotropy.

  4. Improvements to the ICRH antenna time-domain 3D plasma simulation model

    NASA Astrophysics Data System (ADS)

    Smithe, David N.; Jenkins, Thomas G.; King, J. R.

    2015-12-01

    We present a summary of ongoing improvements to the 3D time-domain plasma modeling software that has been used to look at ICRH antennas on Alcator C-Mod, NSTX, and ITER [1]. Our past investigations have shown that in low density cases where the slow wave is propagating, strong amplitude lower hybrid resonant fields can occur. Such a scenario could result in significant parasitic power loss in the SOL. The primary resonance broadening in this case is likely collisions with neutral gas, and thus we are upgrading the model to include realistic neutral gas in the SOL, in order to provide a better understanding of energy balance in these situations. Related to this, we are adding a temporal variation capability to the local plasma density in front of the antenna in order to investigate whether the near fields of the antenna could modify the local density sufficiently to initiate a low density situation. We will start with a simple scalar ponderomotive potential density expulsion model [2] for the density evolution, but are also looking to eventually couple to a more complex fluid treatment that would include tensor pressures and convective physics and sources of neutrals and ionization. We also review continued benchmarking efforts, and ongoing and planned improvements to the computational algorithms, resulting from experience gained during our recent supercomputing runs on the Titan supercomputer, including GPU operations.

  5. Verification and validation of ShipMo3D ship motion predictions in the time and frequency domains

    NASA Astrophysics Data System (ADS)

    McTaggart, Kevin A.

    2011-03-01

    This paper compares frequency domain and time domain predictions from the ShipMo3D ship motion library with observed motions from model tests and sea trials. ShipMo3D evaluates hull radiation and diffraction forces using the frequency domain Green function for zero forward speed, which is a suitable approach for ships travelling at moderate speed (e.g., Froude numbers up to 0.4). Numerical predictions give generally good agreement with experiments. Frequency domain and linear time domain predictions are almost identical. Evaluation of nonlinear buoyancy and incident wave forces using the instantaneous wetted hull surface gives no improvement in numerical predictions. Consistent prediction of roll motions remains a challenge for seakeeping codes due to the associated viscous effects.

  6. Real Time Gabor-Domain Optical Coherence Microscopy for 3D Imaging.

    PubMed

    Rolland, Jannick P; Canavesi, Cristina; Tankam, Patrice; Cogliati, Andrea; Lanis, Mara; Santhanam, Anand P

    2016-01-01

    Fast, robust, nondestructive 3D imaging is needed for the characterization of microscopic tissue structures across various clinical applications. A custom microelectromechanical system (MEMS)-based 2D scanner was developed to achieve, together with a multi-level GPU architecture, 55 kHz fast-axis A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) custom instrument. GD-OCM yields high-definition micrometer-class volumetric images. A dynamic depth of focusing capability through a bio-inspired liquid lens-based microscope design, as in whales' eyes, was developed to enable the high definition instrument throughout a large field of view of 1 mm3 volume of imaging. Developing this technology is prime to enable integration within the workflow of clinical environments. Imaging at an invariant resolution of 2 μm has been achieved throughout a volume of 1 × 1 × 0.6 mm3, acquired in less than 2 minutes. Volumetric scans of human skin in vivo and an excised human cornea are presented. PMID:27046601

  7. Real-time 3D Fourier-domain optical coherence tomography guided microvascular anastomosis

    NASA Astrophysics Data System (ADS)

    Huang, Yong; Ibrahim, Zuhaib; Lee, W. P. A.; Brandacher, Gerald; Kang, Jin U.

    2013-03-01

    Vascular and microvascular anastomosis is considered to be the foundation of plastic and reconstructive surgery, hand surgery, transplant surgery, vascular surgery and cardiac surgery. In the last two decades innovative techniques, such as vascular coupling devices, thermo-reversible poloxamers and suture-less cuff have been introduced. Intra-operative surgical guidance using a surgical imaging modality that provides in-depth view and 3D imaging can improve outcome following both conventional and innovative anastomosis techniques. Optical coherence tomography (OCT) is a noninvasive high-resolution (micron level), high-speed, 3D imaging modality that has been adopted widely in biomedical and clinical applications. In this work we performed a proof-of-concept evaluation study of OCT as an assisted intraoperative and post-operative imaging modality for microvascular anastomosis of rodent femoral vessels. The OCT imaging modality provided lateral resolution of 12 μm and 3.0 μm axial resolution in air and 0.27 volume/s imaging speed, which could provide the surgeon with clearly visualized vessel lumen wall and suture needle position relative to the vessel during intraoperative imaging. Graphics processing unit (GPU) accelerated phase-resolved Doppler OCT (PRDOCT) imaging of the surgical site was performed as a post-operative evaluation of the anastomosed vessels and to visualize the blood flow and thrombus formation. This information could help surgeons improve surgical precision in this highly challenging anastomosis of rodent vessels with diameter less than 0.5 mm. Our imaging modality could not only detect accidental suture through the back wall of lumen but also promptly diagnose and predict thrombosis immediately after reperfusion. Hence, real-time OCT can assist in decision-making process intra-operatively and avoid post-operative complications.

  8. In Vivo 3D Meibography of the Human Eyelid Using Real Time Imaging Fourier-Domain OCT

    PubMed Central

    Hwang, Ho Sik; Shin, Jun Geun; Lee, Byeong Ha; Eom, Tae Joong; Joo, Choun-Ki

    2013-01-01

    Recently, we reported obtaining tomograms of meibomian glands from healthy volunteers using commercial anterior segment optical coherence tomography (AS-OCT), which is widely employed in clinics for examination of the anterior segment. However, we could not create 3D images of the meibomian glands, because the commercial OCT does not have a 3D reconstruction function. In this study we report the creation of 3D images of the meibomian glands by reconstructing the tomograms of these glands using high speed Fourier-Domain OCT (FD-OCT) developed in our laboratory. This research was jointly undertaken at the Department of Ophthalmology, Seoul St. Mary's Hospital (Seoul, Korea) and the Advanced Photonics Research Institute of Gwangju Institute of Science and Technology (Gwangju, Korea) with two healthy volunteers and seven patients with meibomian gland dysfunction. A real time imaging FD-OCT system based on a high-speed wavelength swept laser was developed that had a spectral bandwidth of 100 nm at the 1310 nm center wavelength. The axial resolution was 5 µm and the lateral resolution was 13 µm in air. Using this device, the meibomian glands of nine subjects were examined. A series of tomograms from the upper eyelid measuring 5 mm (from left to right, B-scan) × 2 mm (from upper part to lower part, C-scan) were collected. Three-D images of the meibomian glands were then reconstructed using 3D “data visualization, analysis, and modeling software”. Established infrared meibography was also performed for comparison. The 3D images of healthy subjects clearly showed the meibomian glands, which looked similar to bunches of grapes. These results were consistent with previous infrared meibography results. The meibomian glands were parallel to each other, and the saccular acini were clearly visible. Here we report the successful production of 3D images of human meibomian glands by reconstructing tomograms of these glands with high speed FD-OCT. PMID:23805297

  9. A parallel 3-D staggered grid pseudospectral time domain method for ground-penetrating radar wave simulation

    NASA Astrophysics Data System (ADS)

    Huang, Qinghua; Li, Zhanhui; Wang, Yanbin

    2010-12-01

    We presented a parallel 3-D staggered grid pseudospectral time domain (PSTD) method for simulating ground-penetrating radar (GPR) wave propagation. We took the staggered grid method to weaken the global effect in PSTD and developed a modified fast Fourier transform (FFT) spatial derivative operator to eliminate the wraparound effect due to the implicit periodical boundary condition in FFT operator. After the above improvements, we achieved the parallel PSTD computation based on an overlap domain decomposition method without any absorbing condition for each subdomain, which can significantly reduce the required grids in each overlap subdomain comparing with other proposed algorithms. We test our parallel technique for some numerical models and obtained consistent results with the analytical ones and/or those of the nonparallel PSTD method. The above numerical tests showed that our parallel PSTD algorithm is effective in simulating 3-D GPR wave propagation, with merits of saving computation time, as well as more flexibility in dealing with complicated models without losing the accuracy. The application of our parallel PSTD method in applied geophysics and paleoseismology based on GPR data confirmed the efficiency of our algorithm and its potential applications in various subdisciplines of solid earth geophysics. This study would also provide a useful parallel PSTD approach to the simulation of other geophysical problems on distributed memory PC cluster.

  10. 3D Non-destructive Imaging of Punctures in Polyethylene Composite Armor by THz Time Domain Spectroscopy

    NASA Astrophysics Data System (ADS)

    Palka, N.; Panowicz, R.; Ospald, F.; Beigang, R.

    2015-08-01

    An ultra-high molecular weight polyethylene composite sample totally punctured by a projectile was examined by THz TDS raster scanning method in reflection configuration. The scanning results correctly match the distribution of delaminations inside the sample, which was proven with cross-sectional and frontal views after waterjet cutting. For further analysis, a signal-processing algorithm based on the deconvolution method was developed and the modified reference signal was used to reduce disturbances. The complex refractive index of the sample was determined by transmission TDS technique and was later used for the simulation of pulse propagation by the finite difference time domain method. These simulations verified the correctness of the proposed method and showed its constraints. Using the proposed algorithm, the ambiguous raw THz image was converted into a binary 3D image of the sample, which consists only of two areas: sample—polyethylene and delamination—air. As a result, a clear image of the distribution of delaminations with their spatial extent was obtained which can be used for further comparative analysis. The limitation of the proposed method is that parts of the central area of the puncture cannot be analyzed because tilted layers deflect the incident signal.

  11. Reconstruction for Time-Domain In Vivo EPR 3D Multigradient Oximetric Imaging—A Parallel Processing Perspective

    PubMed Central

    Dharmaraj, Christopher D.; Thadikonda, Kishan; Fletcher, Anthony R.; Doan, Phuc N.; Devasahayam, Nallathamby; Matsumoto, Shingo; Johnson, Calvin A.; Cook, John A.; Mitchell, James B.; Subramanian, Sankaran; Krishna, Murali C.

    2009-01-01

    Three-dimensional Oximetric Electron Paramagnetic Resonance Imaging using the Single Point Imaging modality generates unpaired spin density and oxygen images that can readily distinguish between normal and tumor tissues in small animals. It is also possible with fast imaging to track the changes in tissue oxygenation in response to the oxygen content in the breathing air. However, this involves dealing with gigabytes of data for each 3D oximetric imaging experiment involving digital band pass filtering and background noise subtraction, followed by 3D Fourier reconstruction. This process is rather slow in a conventional uniprocessor system. This paper presents a parallelization framework using OpenMP runtime support and parallel MATLAB to execute such computationally intensive programs. The Intel compiler is used to develop a parallel C++ code based on OpenMP. The code is executed on four Dual-Core AMD Opteron shared memory processors, to reduce the computational burden of the filtration task significantly. The results show that the parallel code for filtration has achieved a speed up factor of 46.66 as against the equivalent serial MATLAB code. In addition, a parallel MATLAB code has been developed to perform 3D Fourier reconstruction. Speedup factors of 4.57 and 4.25 have been achieved during the reconstruction process and oximetry computation, for a data set with 23 × 23 × 23 gradient steps. The execution time has been computed for both the serial and parallel implementations using different dimensions of the data and presented for comparison. The reported system has been designed to be easily accessible even from low-cost personal computers through local internet (NIHnet). The experimental results demonstrate that the parallel computing provides a source of high computational power to obtain biophysical parameters from 3D EPR oximetric imaging, almost in real-time. PMID:19672315

  12. Reconstruction for time-domain in vivo EPR 3D multigradient oximetric imaging--a parallel processing perspective.

    PubMed

    Dharmaraj, Christopher D; Thadikonda, Kishan; Fletcher, Anthony R; Doan, Phuc N; Devasahayam, Nallathamby; Matsumoto, Shingo; Johnson, Calvin A; Cook, John A; Mitchell, James B; Subramanian, Sankaran; Krishna, Murali C

    2009-01-01

    Three-dimensional Oximetric Electron Paramagnetic Resonance Imaging using the Single Point Imaging modality generates unpaired spin density and oxygen images that can readily distinguish between normal and tumor tissues in small animals. It is also possible with fast imaging to track the changes in tissue oxygenation in response to the oxygen content in the breathing air. However, this involves dealing with gigabytes of data for each 3D oximetric imaging experiment involving digital band pass filtering and background noise subtraction, followed by 3D Fourier reconstruction. This process is rather slow in a conventional uniprocessor system. This paper presents a parallelization framework using OpenMP runtime support and parallel MATLAB to execute such computationally intensive programs. The Intel compiler is used to develop a parallel C++ code based on OpenMP. The code is executed on four Dual-Core AMD Opteron shared memory processors, to reduce the computational burden of the filtration task significantly. The results show that the parallel code for filtration has achieved a speed up factor of 46.66 as against the equivalent serial MATLAB code. In addition, a parallel MATLAB code has been developed to perform 3D Fourier reconstruction. Speedup factors of 4.57 and 4.25 have been achieved during the reconstruction process and oximetry computation, for a data set with 23 x 23 x 23 gradient steps. The execution time has been computed for both the serial and parallel implementations using different dimensions of the data and presented for comparison. The reported system has been designed to be easily accessible even from low-cost personal computers through local internet (NIHnet). The experimental results demonstrate that the parallel computing provides a source of high computational power to obtain biophysical parameters from 3D EPR oximetric imaging, almost in real-time. PMID:19672315

  13. [Real time 3D echocardiography].

    PubMed

    Bauer, F; Shiota, T; Thomas, J D

    2001-07-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients. PMID:11494630

  14. [Real time 3D echocardiography

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Thomas, J. D.

    2001-01-01

    Three-dimensional representation of the heart is an old concern. Usually, 3D reconstruction of the cardiac mass is made by successive acquisition of 2D sections, the spatial localisation and orientation of which require complex guiding systems. More recently, the concept of volumetric acquisition has been introduced. A matricial emitter-receiver probe complex with parallel data processing provides instantaneous of a pyramidal 64 degrees x 64 degrees volume. The image is restituted in real time and is composed of 3 planes (planes B and C) which can be displaced in all spatial directions at any time during acquisition. The flexibility of this system of acquisition allows volume and mass measurement with greater accuracy and reproducibility, limiting inter-observer variability. Free navigation of the planes of investigation allows reconstruction for qualitative and quantitative analysis of valvular heart disease and other pathologies. Although real time 3D echocardiography is ready for clinical usage, some improvements are still necessary to improve its conviviality. Then real time 3D echocardiography could be the essential tool for understanding, diagnosis and management of patients.

  15. 3D pseudospectral time domain for modeling second-harmonic generation in periodically poled lithium niobate ridge-type waveguides

    NASA Astrophysics Data System (ADS)

    Devaux, Fabrice; Lantz, Eric; Chauvet, Mathieu

    2016-04-01

    We report an application of the tri-dimensional pseudo-spectral time domain algorithm, that solves with accuracy the nonlinear Maxwell's equations, to predict second harmonic generation in lithium niobate ridge-type waveguides with high index contrast. Characteristics of the nonlinear process such as conversion efficiency as well as impact of the multimode character of the waveguide are investigated as a function of the waveguide geometry in uniformly and periodically poled medium.

  16. 3D Lithospheric Imaging by Time-Domain Full-Waveform Inversion of Teleseismic Body-Waves

    NASA Astrophysics Data System (ADS)

    Beller, S.; Monteiller, V.; Operto, S.; Nolet, G.; Combe, L.; Metivier, L.; Virieux, J.; Nissen-Meyer, T.; Paul, A.

    2014-12-01

    With the deployment of dense seismic arrays and the continuous growth of computing facilities, full-waveform inversion (FWI) of teleseismic data has become a method of choice for high-resolution lithospheric imaging. FWI can be recast as a local optimization problem that seeks to estimate Earth's elastic properties by iteratively minimizing the misfit function between observed and modeled seismograms.In passive teleseismic configurations, the seismic source no longer corresponds to a point source embedded in the targeted medium but rather corresponds to a wavefront incoming from the outside of the model. We develop a 3-dimensional time-domain full-waveform inversion program that is more designed for this configuration. The gradient of the misfit function is efficiently computed with the adjoint-state method. A velocity-stress finite-difference time-domain modeling engine, which is interfaced with the so-called total-field/scattered-field method, is used to propagate in the targeted medium the incident wavefield inferred from a global Earth simulation (AxiSEM). Such interfacing is required to account for the multiple arrivals in the incoming wavefield and the sphericity of the Earth. Despite the limited number of nearly plane-wave sources, the interaction of the incident wavefield with the topography (P-Sv conversions and P-P reflections acting as secondary sources) provides a suitable framework to record both transmitted wavefields and reflected wavefields from lithospheric reflectors. These recordings of both transmitted and reflected waves makes FWI amenable to a broadband-wavenumber (i.e., high resolution) reconstruction of the lithosphere.Feasibility of the method is assessed with a realistic synthetic model representative of the Western Alps. One key issue is the estimation of the temporal source excitation, as there might be some trade-off between the source estimation and the subsurface update. To avoid being trapped in a local minimum, we follow a

  17. 3D acoustic wave modelling with time-space domain dispersion-relation-based finite-difference schemes and hybrid absorbing boundary conditions

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Sen, Mrinal K.

    2011-09-01

    Most conventional finite-difference methods adopt second-order temporal and (2M)th-order spatial finite-difference stencils to solve the 3D acoustic wave equation. When spatial finite-difference stencils devised from the time-space domain dispersion relation are used to replace these conventional spatial finite-difference stencils devised from the space domain dispersion relation, the accuracy of modelling can be increased from second-order along any directions to (2M)th-order along 48 directions. In addition, the conventional high-order spatial finite-difference modelling accuracy can be improved by using a truncated finite-difference scheme. In this paper, we combine the time-space domain dispersion-relation-based finite difference scheme and the truncated finite-difference scheme to obtain optimised spatial finite-difference coefficients and thus to significantly improve the modelling accuracy without increasing computational cost, compared with the conventional space domain dispersion-relation-based finite difference scheme. We developed absorbing boundary conditions for the 3D acoustic wave equation, based on predicting wavefield values in a transition area by weighing wavefield values from wave equations and one-way wave equations. Dispersion analyses demonstrate that high-order spatial finite-difference stencils have greater accuracy than low-order spatial finite-difference stencils for high frequency components of wavefields, and spatial finite-difference stencils devised in the time-space domain have greater precision than those devised in the space domain under the same discretisation. The modelling accuracy can be improved further by using the truncated spatial finite-difference stencils. Stability analyses show that spatial finite-difference stencils devised in the time-space domain have better stability condition. Numerical modelling experiments for homogeneous, horizontally layered and Society of Exploration Geophysicists/European Association of

  18. 3D Time-domain wave modeling in fluid-solid coupled media: a cell-based finite-difference method approach

    NASA Astrophysics Data System (ADS)

    Lee, H.; Min, D.; Lim, S.; Yang, J.; Kwon, B.; Yoo, H.

    2009-12-01

    In a conventional marine seismic data analysis, pressure data have been usually interpreted on the basis of acoustic wave equation. The acoustic wave equation, however, only deals with P-wave propagation, and it cannot correctly describe the wave propagation in acoustic-elastic (fluid-solid) coupled media. Recently, in 4C OBC survey (4-component ocean bottom cable), it is possible to acquire both pressure and 3-component displacements (measured at the sea-bottom). Combining pressure and displacement data allows us to interpret subsurface structures more accurately. In order to accurately simulate wave propagation in fluid-solid coupled media, we need an acoustic-elastic coupled modeling algorithm, which deals with displacements in elastic region and pressure in acoustic region. For waveform inversion and reverse-time migration that require a great number of forward modeling, it is essential to develop an efficient scheme that reduces computing time and computer core memory. In this study, we present a 3D time-domain acoustic-elastic coupled modeling algorithm on the basis of the cell-based finite difference method. The cell-based method has proven to properly describe the free-surface boundary, which indicates that it will also properly describe the fluid-solid interface boundaries. In the acoustic-elastic coupled modeling, we first compose cell-based finite differences individually for the 3D acoustic and elastic media, and then combine the differences using the fluid-solid interface boundary conditions. Considering that the 2D acoustic-elastic coupled modeling algorithm gives numerical solutions comparable to analytic solutions, we expect that the 3D acoustic-elastic coupled modeling will correctly describe wave propagation in the fluid-solid coupled media. We apply our algorithm to 3D horizontal two- and three-layer models. Numerical experiments show that the cell-based coupled modeling algorithm properly describes S- and converted waves as well as P-waves. The

  19. 3D-spectral domain computational imaging

    NASA Astrophysics Data System (ADS)

    Anderson, Trevor; Segref, Armin; Frisken, Grant; Ferra, Herman; Lorenser, Dirk; Frisken, Steven

    2016-03-01

    We present a proof-of-concept experiment utilizing a novel "snap-shot" spectral domain OCT technique that captures a phase coherent volume in a single frame. The sample is illuminated with a collimated beam of 75 μm diameter and the back-reflected light is analyzed by a 2-D matrix of spectral interferograms. A key challenge that is addressed is simultaneously maintaining lateral and spectral phase coherence over the imaged volume in the presence of sample motion. Digital focusing is demonstrated for 5.0 μm lateral resolution over an 800 μm axial range.

  20. Coverage Assessment and Target Tracking in 3D Domains

    PubMed Central

    Boudriga, Noureddine; Hamdi, Mohamed; Iyengar, Sitharama

    2011-01-01

    Recent advances in integrated electronic devices motivated the use of Wireless Sensor Networks (WSNs) in many applications including domain surveillance and mobile target tracking, where a number of sensors are scattered within a sensitive region to detect the presence of intruders and forward related events to some analysis center(s). Obviously, sensor deployment should guarantee an optimal event detection rate and should reduce coverage holes. Most of the coverage control approaches proposed in the literature deal with two-dimensional zones and do not develop strategies to handle coverage in three-dimensional domains, which is becoming a requirement for many applications including water monitoring, indoor surveillance, and projectile tracking. This paper proposes efficient techniques to detect coverage holes in a 3D domain using a finite set of sensors, repair the holes, and track hostile targets. To this end, we use the concepts of Voronoi tessellation, Vietoris complex, and retract by deformation. We show in particular that, through a set of iterative transformations of the Vietoris complex corresponding to the deployed sensors, the number of coverage holes can be computed with a low complexity. Mobility strategies are also proposed to repair holes by moving appropriately sensors towards the uncovered zones. The tracking objective is to set a non-uniform WSN coverage within the monitored domain to allow detecting the target(s) by the set of sensors. We show, in particular, how the proposed algorithms adapt to cope with obstacles. Simulation experiments are carried out to analyze the efficiency of the proposed models. To our knowledge, repairing and tracking is addressed for the first time in 3D spaces with different sensor coverage schemes. PMID:22163733

  1. A modified and stable version of a perfectly matched layer technique for the 3-d second order wave equation in time domain with an application to aeroacoustics

    PubMed Central

    Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo

    2013-01-01

    We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems. PMID:23888085

  2. A modified and stable version of a perfectly matched layer technique for the 3-d second order wave equation in time domain with an application to aeroacoustics.

    PubMed

    Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo

    2013-02-15

    We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems. PMID:23888085

  3. A modified and stable version of a perfectly matched layer technique for the 3-d second order wave equation in time domain with an application to aeroacoustics

    NASA Astrophysics Data System (ADS)

    Kaltenbacher, Barbara; Kaltenbacher, Manfred; Sim, Imbo

    2013-02-01

    We consider the second order wave equation in an unbounded domain and propose an advanced perfectly matched layer (PML) technique for its efficient and reliable simulation. In doing so, we concentrate on the time domain case and use the finite-element (FE) method for the space discretization. Our un-split-PML formulation requires four auxiliary variables within the PML region in three space dimensions. For a reduced version (rPML), we present a long time stability proof based on an energy analysis. The numerical case studies and an application example demonstrate the good performance and long time stability of our formulation for treating open domain problems.

  4. 3D MR imaging in real time

    NASA Astrophysics Data System (ADS)

    Guttman, Michael A.; McVeigh, Elliot R.

    2001-05-01

    A system has been developed to produce live 3D volume renderings from an MR scanner. Whereas real-time 2D MR imaging has been demonstrated by several groups, 3D volumes are currently rendered off-line to gain greater understanding of anatomical structures. For example, surgical planning is sometimes performed by viewing 2D images or 3D renderings from previously acquired image data. A disadvantage of this approach is misregistration which could occur if the anatomy changes due to normal muscle contractions or surgical manipulation. The ability to produce volume renderings in real-time and present them in the magnet room could eliminate this problem, and enable or benefit other types of interventional procedures. The system uses the data stream generated by a fast 2D multi- slice pulse sequence to update a volume rendering immediately after a new slice is available. We demonstrate some basic types of user interaction with the rendering during imaging at a rate of up to 20 frames per second.

  5. Higher-order in time "quasi-unconditionally stable" ADI solvers for the compressible Navier-Stokes equations in 2D and 3D curvilinear domains

    NASA Astrophysics Data System (ADS)

    Bruno, Oscar P.; Cubillos, Max

    2016-02-01

    This paper introduces alternating-direction implicit (ADI) solvers of higher order of time-accuracy (orders two to six) for the compressible Navier-Stokes equations in two- and three-dimensional curvilinear domains. The higher-order accuracy in time results from 1) An application of the backward differentiation formulae time-stepping algorithm (BDF) in conjunction with 2) A BDF-like extrapolation technique for certain components of the nonlinear terms (which makes use of nonlinear solves unnecessary), as well as 3) A novel application of the Douglas-Gunn splitting (which greatly facilitates handling of boundary conditions while preserving higher-order accuracy in time). As suggested by our theoretical analysis of the algorithms for a variety of special cases, an extensive set of numerical experiments clearly indicate that all of the BDF-based ADI algorithms proposed in this paper are "quasi-unconditionally stable" in the following sense: each algorithm is stable for all couples (h , Δt)of spatial and temporal mesh sizes in a problem-dependent rectangular neighborhood of the form (0 ,Mh) × (0 ,Mt). In other words, for each fixed value of Δt below a certain threshold, the Navier-Stokes solvers presented in this paper are stable for arbitrarily small spatial mesh-sizes. The second-order formulation has further been rigorously shown to be unconditionally stable for linear hyperbolic and parabolic equations in two-dimensional space. Although implicit ADI solvers for the Navier-Stokes equations with nominal second-order of temporal accuracy have been proposed in the past, the algorithms presented in this paper are the first ADI-based Navier-Stokes solvers for which second-order or better accuracy has been verified in practice under non-trivial (non-periodic) boundary conditions.

  6. Real-Time 3D Visualization

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Butler Hine, former director of the Intelligent Mechanism Group (IMG) at Ames Research Center, and five others partnered to start Fourth Planet, Inc., a visualization company that specializes in the intuitive visual representation of dynamic, real-time data over the Internet and Intranet. Over a five-year period, the then NASA researchers performed ten robotic field missions in harsh climes to mimic the end- to-end operations of automated vehicles trekking across another world under control from Earth. The core software technology for these missions was the Virtual Environment Vehicle Interface (VEVI). Fourth Planet has released VEVI4, the fourth generation of the VEVI software, and NetVision. VEVI4 is a cutting-edge computer graphics simulation and remote control applications tool. The NetVision package allows large companies to view and analyze in virtual 3D space such things as the health or performance of their computer network or locate a trouble spot on an electric power grid. Other products are forthcoming. Fourth Planet is currently part of the NASA/Ames Technology Commercialization Center, a business incubator for start-up companies.

  7. Real-time monitoring of 3D cell culture using a 3D capacitance biosensor.

    PubMed

    Lee, Sun-Mi; Han, Nalae; Lee, Rimi; Choi, In-Hong; Park, Yong-Beom; Shin, Jeon-Soo; Yoo, Kyung-Hwa

    2016-03-15

    Three-dimensional (3D) cell cultures have recently received attention because they represent a more physiologically relevant environment compared to conventional two-dimensional (2D) cell cultures. However, 2D-based imaging techniques or cell sensors are insufficient for real-time monitoring of cellular behavior in 3D cell culture. Here, we report investigations conducted with a 3D capacitance cell sensor consisting of vertically aligned pairs of electrodes. When GFP-expressing human breast cancer cells (GFP-MCF-7) encapsulated in alginate hydrogel were cultured in a 3D cell culture system, cellular activities, such as cell proliferation and apoptosis at different heights, could be monitored non-invasively and in real-time by measuring the change in capacitance with the 3D capacitance sensor. Moreover, we were able to monitor cell migration of human mesenchymal stem cells (hMSCs) with our 3D capacitance sensor. PMID:26386332

  8. Volumetric (3D) compressive sensing spectral domain optical coherence tomography

    PubMed Central

    Xu, Daguang; Huang, Yong; Kang, Jin U.

    2014-01-01

    In this work, we proposed a novel three-dimensional compressive sensing (CS) approach for spectral domain optical coherence tomography (SD OCT) volumetric image acquisition and reconstruction. Instead of taking a spectral volume whose size is the same as that of the volumetric image, our method uses a sub set of the original spectral volume that is under-sampled in all three dimensions, which reduces the amount of spectral measurements to less than 20% of that required by the Shan-non/Nyquist theory. The 3D image is recovered from the under-sampled spectral data dimension-by-dimension using the proposed three-step CS reconstruction strategy. Experimental results show that our method can significantly reduce the sampling rate required for a volumetric SD OCT image while preserving the image quality. PMID:25426320

  9. Ames Lab 101: Real-Time 3D Imaging

    ScienceCinema

    Zhang, Song

    2012-08-29

    Ames Laboratory scientist Song Zhang explains his real-time 3-D imaging technology. The technique can be used to create high-resolution, real-time, precise, 3-D images for use in healthcare, security, and entertainment applications.

  10. [Real time 3D echocardiography in congenital heart disease].

    PubMed

    Acar, P; Dulac, Y; Taktak, A; Villacèque, M

    2004-05-01

    The introduction of the 3D mode in echocardiography has led to its use in everyday clinical practice. One hundred and fifty real time 3D echocardiographic examinations were performed in 20 foetus, 110 children and 20 adults with various congenital heart lesions (shunts, valvular lesions, aortic diseases). The 4x matricial probe enables the instantaneous acquisition of transthoracic volumes. Four modes of 3D imaging were used: real time, total volume, colour Doppler and biplane. Quantitative measurements were performed at an outlying station. The feasibility of the method in the foetus, the child and the adult was respectively 90%, 99% and 85%. Real time 3D echocardiography did not affect the diagnoses made by standard echocardiography. The 3D imaging gave a more accurate description of atrial septal defects and congenital valvular lesions. Biplane imaging was decisive in the quantitative approach to aortic dilatation of Marfan's syndrome and in segmental analysis of the foetal heart. 3D colour Doppler imaging has been disappointing but the possibilities of volumic quantification of blood flow are very promising. The present limitations of the method are the inadequate resolution in the small child and the absence of quantitative measurement on the echograph. The facility of utilisation of the matricial probe should lead to routine usage of 3D echocardiography as with 2D and the Doppler modes. Its value should be decisive in many congenital cardiac lesions requiring surgery or interventional catheterisation. PMID:15214550

  11. Real time 3D and heterogeneous data fusion

    SciTech Connect

    Little, C.Q.; Small, D.E.

    1998-03-01

    This project visualizes characterization data in a 3D setting, in real time. Real time in this sense means collecting the data and presenting it before it delays the user, and processing faster than the acquisition systems so no bottlenecks occur. The goals have been to build a volumetric viewer to display 3D data, demonstrate projecting other data, such as images, onto the 3D data, and display both the 3D and projected images as fast as the data became available. The authors have examined several ways to display 3D surface data. The most effective was generating polygonal surface meshes. They have created surface maps form a continuous stream of 3D range data, fused image data onto the geometry, and displayed the data with a standard 3D rendering package. In parallel with this, they have developed a method to project real-time images onto the surface created. A key component is mapping the data on the correct surfaces, which requires a-priori positional information along with accurate calibration of the camera and lens system.

  12. Segmented Domain Decomposition Multigrid For 3-D Turbomachinery Flows

    NASA Technical Reports Server (NTRS)

    Celestina, M. L.; Adamczyk, J. J.; Rubin, S. G.

    2001-01-01

    A Segmented Domain Decomposition Multigrid (SDDMG) procedure was developed for three-dimensional viscous flow problems as they apply to turbomachinery flows. The procedure divides the computational domain into a coarse mesh comprised of uniformly spaced cells. To resolve smaller length scales such as the viscous layer near a surface, segments of the coarse mesh are subdivided into a finer mesh. This is repeated until adequate resolution of the smallest relevant length scale is obtained. Multigrid is used to communicate information between the different grid levels. To test the procedure, simulation results will be presented for a compressor and turbine cascade. These simulations are intended to show the ability of the present method to generate grid independent solutions. Comparisons with data will also be presented. These comparisons will further demonstrate the usefulness of the present work for they allow an estimate of the accuracy of the flow modeling equations independent of error attributed to numerical discretization.

  13. 3D frequency-domain finite-difference modeling of acoustic wave propagation

    NASA Astrophysics Data System (ADS)

    Operto, S.; Virieux, J.

    2006-12-01

    -memory computers. The MUMPS solver is based on a multifrontal method for LU factorization. We used the METIS algorithm to perform re-ordering of the matrix coefficients before factorization. Four grid points per minimum wavelength is used for discretization. We applied our algorithm to the 3D SEG/EAGE synthetic onshore OVERTHRUST model of dimensions 20 x 20 x 4.65 km. The velocities range between 2 and 6 km/s. We performed the simulations using 192 processors with 2 Gbytes of RAM memory per processor. We performed simulations for the 5 Hz, 7 Hz and 10 Hz frequencies in some fractions of the OVERTHRUST model. The grid interval was 100 m, 75 m and 50 m respectively. The grid dimensions were 207x207x53, 275x218x71 and 409x109x102 respectively corresponding to 100, 80 and 25 percents of the model respectively. The time for factorization is 20 mn, 108 mn and 163 mn respectively. The time for resolution was 3.8, 9.3 and 10.3 s per source. The total memory used during factorization is 143, 384 and 449 Gbytes respectively. One can note the huge memory requirement for factorization and the efficiency of the direct method to compute solutions for a large number of sources. This highlights the respective drawback and merit of the frequency-domain approach with respect to the time- domain counterpart. These results show that 3D acoustic frequency-domain wave propagation modeling can be performed at low frequencies using direct solver on large clusters of Pcs. This forward modeling algorithm may be used in the future as a tool to image the first kilometers of the crust by frequency-domain full-waveform inversion. For larger problems, we will use the out-of-core memory during factorization that has been implemented by the authors of MUMPS.

  14. Efficient one-pass 3-D time migration

    SciTech Connect

    Brzostowski, M.A.; Snyder, F.F.C.; Smith, P.J.

    1996-11-01

    An efficient one-pass 3-D time migration algorithm is introduced as an alternative to Ristow`s splitting approach. This algorithm extends Black and Leong`s k{sub y}-separation approach with a time-dependent Stolt stretch operation called dilation. Migration using k{sub y} dilation consists of a single pass over the 3-D data volume after k{sub y} slices are formed with each k{sub y} slice downward continued independently. A number of downward continuation algorithms based upon the 3-D wave equation may be used. Dilation accommodates any lateral variations in velocity before the 3-D data volume is decomposed into k{sub y} slices via a Fourier transform. An inverse dilation operation is performed after the downward-continuation operation and after the data volume have been inverse Fourier transformed subsequently along the k{sub y} direction. Migration using the k{sub y}-dilation approach yields a one-pass 3-D time migration algorithm that is practical and efficient where the medium velocity is smoothly varying.

  15. Structure of Pseudoknot PK26 Shows 3D Domain Swapping in an RNA

    NASA Technical Reports Server (NTRS)

    Lietzke, Susan E; Barnes, Cindy L.

    1998-01-01

    3D domain swapping provides a facile pathway for the evolution of oligomeric proteins and allosteric mechanisms and a means for using monomer-oligomer equilibria to regulate biological activity. The term "3D domain swapping" describes the exchange of identical domains between two protein monomers to create an oligomer. 3D domain swapping has, so far, only been recognized in proteins. In this study, the structure of the pseudoknot PK26 is reported and it is a clear example of 3D domain swapping in RNA. PK26 was chosen for study because RNA pseudoknots are required structures in several biological processes and they arise frequently in in vitro selection experiments directed against protein targets. PK26 specifically inhibits HIV-1 reverse transcriptase with nanomolar affinity. We have now determined the 3.1 A resolution crystal structure of PK26 and find that it forms a 3D domain swapped dimer. PK26 shows extensive base pairing between and within strands. Formation of the dimer requires the linker region between the pseudoknot folds to adopt a unique conformation that allows a base within a helical stem to skip one base in the stacking register. Rearrangement of the linker would permit a monomeric pseudoknot to form. This structure shows how RNA can use 3D domain swapping to build large scale oligomers like the putative hexamer in the packaging RNA of bacteriophage Phi29.

  16. Time Series Analysis of 3D Coordinates Using Nonstochastic Observations

    NASA Astrophysics Data System (ADS)

    Velsink, Hiddo

    2016-03-01

    Adjustment and testing of a combination of stochastic and nonstochastic observations is applied to the deformation analysis of a time series of 3D coordinates. Nonstochastic observations are constant values that are treated as if they were observations. They are used to formulate constraints on the unknown parameters of the adjustment problem. Thus they describe deformation patterns. If deformation is absent, the epochs of the time series are supposed to be related via affine, similarity or congruence transformations. S-basis invariant testing of deformation patterns is treated. The model is experimentally validated by showing the procedure for a point set of 3D coordinates, determined from total station measurements during five epochs. The modelling of two patterns, the movement of just one point in several epochs, and of several points, is shown. Full, rank deficient covariance matrices of the 3D coordinates, resulting from free network adjustments of the total station measurements of each epoch, are used in the analysis.

  17. 3D Laplace-domain full waveform inversion using a single GPU card

    NASA Astrophysics Data System (ADS)

    Shin, Jungkyun; Ha, Wansoo; Jun, Hyunggu; Min, Dong-Joo; Shin, Changsoo

    2014-06-01

    The Laplace-domain full waveform inversion is an efficient long-wavelength velocity estimation method for seismic datasets lacking low-frequency components. However, to invert a 3D velocity model, a large cluster of CPU cores have commonly been required to overcome the extremely long computing time caused by a large impedance matrix and a number of source positions. In this study, a workstation with a single GPU card (NVIDIA GTX 580) is successfully used for the 3D Laplace-domain full waveform inversion rather than a large cluster of CPU cores. To exploit a GPU for our inversion algorithm, the routine for the iterative matrix solver is ported to the CUDA programming language for forward and backward modeling parts with minimized modification of the remaining parts, which were originally written in Fortran 90. Using a uniformly structured grid set, nonzero values in the sparse impedance matrix can be arranged according to certain rules, which efficiently parallelize the preconditioned conjugate gradient method for a number of threads contained in the GPU card. We perform a numerical experiment to verify the accuracy of a floating point operation performed by a GPU to calculate the Laplace-domain wavefield. We also measure the efficiencies of the original CPU and modified GPU programs using a cluster of CPU cores and a workstation with a GPU card, respectively. Through the analysis, the parallelized inversion code for a GPU achieves the speedup of 14.7-24.6x compared to a CPU-based serial code depending on the degrees of freedom of the impedance matrix. Finally, the practicality of the proposed algorithm is examined by inverting a 3D long-wavelength velocity model using wide azimuth real datasets in 3.7 days.

  18. Large-scale 3D inversion of frequency domain controlled-source electromagnetic data

    NASA Astrophysics Data System (ADS)

    Miller, C. R.; Routh, P. S.; Donaldson, P.; Oldenburg, D. W.

    2005-05-01

    these targets. In this paper we will present a strategy to invert a large-scale EM data set. Haber, E., Ascher, U. and Oldenburg, D., 2004, Inversion of 3D electromagnetic data in frequency and time domain using an inexact all-at-once approach: Geophysics, Soc. of Expl. Geophys., 69, 1216-1228.

  19. VPython: Writing Real-time 3D Physics Programs

    NASA Astrophysics Data System (ADS)

    Chabay, Ruth

    2001-06-01

    VPython (http://cil.andrew.cmu.edu/projects/visual) combines the Python programming language with an innovative 3D graphics module called Visual, developed by David Scherer. Designed to make 3D physics simulations accessible to novice programmers, VPython allows the programmer to write a purely computational program without any graphics code, and produces an interactive realtime 3D graphical display. In a program 3D objects are created and their positions modified by computational algorithms. Running in a separate thread, the Visual module monitors the positions of these objects and renders them many times per second. Using the mouse, one can zoom and rotate to navigate through the scene. After one hour of instruction, students in an introductory physics course at Carnegie Mellon University, including those who have never programmed before, write programs in VPython to model the behavior of physical systems and to visualize fields in 3D. The Numeric array processing module allows the construction of more sophisticated simulations and models as well. VPython is free and open source. The Visual module is based on OpenGL, and runs on Windows, Linux, and Macintosh.

  20. Vehicle teleoperation using 3D maps and GPS time synchronization.

    PubMed

    Suzuki, Taro; Amano, Yoshiharu; Hashizume, Takumi; Kubo, Nobuaki

    2013-01-01

    In conventional vehicle teleoperation systems, using low-bandwidth, high-delay transmission links causes a serious problem for remote control of the vehicles. To solve this problem, a proposed teleoperation system employs 3D maps and GPS time synchronization. Two GPS receivers measure the transmission delay, which the system uses to estimate the vehicle's location and orientation. Field experiments show that the 3D-map-based interface lets users easily comprehend the remote environment while navigating a vehicle. The experiments also show that taking communication delays into account improves maneuverability. PMID:24808084

  1. Real-time structured light intraoral 3D measurement pipeline

    NASA Astrophysics Data System (ADS)

    Gheorghe, Radu; Tchouprakov, Andrei; Sokolov, Roman

    2013-02-01

    Computer aided design and manufacturing (CAD/CAM) is increasingly becoming a standard feature and service provided to patients in dentist offices and denture manufacturing laboratories. Although the quality of the tools and data has slowly improved in the last years, due to various surface measurement challenges, practical, accurate, invivo, real-time 3D high quality data acquisition and processing still needs improving. Advances in GPU computational power have allowed for achieving near real-time 3D intraoral in-vivo scanning of patient's teeth. We explore in this paper, from a real-time perspective, a hardware-software-GPU solution that addresses all the requirements mentioned before. Moreover we exemplify and quantify the hard and soft deadlines required by such a system and illustrate how they are supported in our implementation.

  2. 3-D electromagnetic modeling for very early time sounding of shallow targets using integral equations

    SciTech Connect

    Xiong, Z.; Tripp, A.C.

    1994-12-31

    This paper presents an integral equation algorithm for 3D EM modeling at high frequencies for applications in engineering an environmental studies. The integral equation method remains the same for low and high frequencies, but the dominant roles of the displacements currents complicate both numerical treatments and interpretations. With singularity extraction technique they successively extended the application of the Hankel filtering technique to the computation of Hankel integrals occurring in high frequency EM modeling. Time domain results are calculated from frequency domain results via Fourier transforms. While frequency domain data are not obvious for interpretations, time domain data show wave-like pictures that resemble seismograms. Both 1D and 3D numerical results show clearly the layer interfaces.

  3. Real-time, 3-D ultrasound with multiple transducer arrays.

    PubMed

    Fronheiser, Matthew P; Light, Edward D; Idriss, Salim F; Wolf, Patrick D; Smith, Stephen W

    2006-01-01

    Modifications were made to a commercial real-time, three-dimensional (3-D) ultrasound system for near simultaneous 3-D scanning with two matrix array transducers. As a first illustration, a transducer cable assembly was modified to incorporate two independent, 3-D intra-cardiac echo catheters, a 7 Fr (2.3 mm O.D.) side scanning catheter and a 14 Fr (4.7 mm O.D) forward viewing catheter with accessory port, each catheter using 85 channels operating at 5 MHz. For applications in treatment of atrial fibrillation, the goal is to place the sideviewing catheter within the coronary sinus to view the whole left atrium, including a pulmonary vein. Meanwhile, the forward-viewing catheter inserted within the left atrium is directed toward the ostium of a pulmonary vein for therapy using the integrated accessory port. Using preloaded, phasing data, the scanner switches between catheters automatically, at the push of a button, with a delay of about 1 second, so that the clinician can view the therapy catheter with the coronary sinus catheter and vice versa. Preliminary imaging studies in a tissue phantom and in vivo show that our system successfully guided the forward-viewing catheter toward a target while being imaged with the sideviewing catheter. The forward-viewing catheter then was activated to monitor the target while we mimicked therapy delivery. In the future, the system will switch between 3-D probes on a line-by-line basis and display both volumes simultaneously. PMID:16471436

  4. Extra Dimensions: 3D and Time in PDF Documentation

    SciTech Connect

    Graf, Norman A.; /SLAC

    2011-11-10

    High energy physics is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide audience. In this talk, we present examples of HEP applications which take advantage of this functionality. We demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input. Using this technique, higher dimensional data, such as LEGO plots or time-dependent information can be included in PDF files. In principle, a complete event display, with full interactivity, can be incorporated into a PDF file. This would allow the end user not only to customize the view and representation of the data, but to access the underlying data itself.

  5. Extra dimensions: 3d and time in pdf documentation

    NASA Astrophysics Data System (ADS)

    Graf, N. A.

    2008-07-01

    High energy physics is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide audience. In this talk, we present examples of HEP applications which take advantage of this functionality. We demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input. Using this technique, higher dimensional data, such as LEGO plots or time-dependent information can be included in PDF files. In principle, a complete event display, with full interactivity, can be incorporated into a PDF file. This would allow the end user not only to customize the view and representation of the data, but to access the underlying data itself.

  6. Tensor3D: A computer graphics program to simulate 3D real-time deformation and visualization of geometric bodies

    NASA Astrophysics Data System (ADS)

    Pallozzi Lavorante, Luca; Dirk Ebert, Hans

    2008-07-01

    Tensor3D is a geometric modeling program with the capacity to simulate and visualize in real-time the deformation, specified through a tensor matrix and applied to triangulated models representing geological bodies. 3D visualization allows the study of deformational processes that are traditionally conducted in 2D, such as simple and pure shears. Besides geometric objects that are immediately available in the program window, the program can read other models from disk, thus being able to import objects created with different open-source or proprietary programs. A strain ellipsoid and a bounding box are simultaneously shown and instantly deformed with the main object. The principal axes of strain are visualized as well to provide graphical information about the orientation of the tensor's normal components. The deformed models can also be saved, retrieved later and deformed again, in order to study different steps of progressive strain, or to make this data available to other programs. The shape of stress ellipsoids and the corresponding Mohr circles defined by any stress tensor can also be represented. The application was written using the Visualization ToolKit, a powerful scientific visualization library in the public domain. This development choice, allied to the use of the Tcl/Tk programming language, which is independent on the host computational platform, makes the program a useful tool for the study of geometric deformations directly in three dimensions in teaching as well as research activities.

  7. Optimized 3D Ultrashort Echo Time Pulmonary MRI

    PubMed Central

    Johnson, Kevin M.; Fain, Sean B.; Schiebler, Mark L.; Nagle, Scott

    2012-01-01

    Purpose To optimize 3D radial ultrashort echo time MRI for high resolution whole-lung imaging. Methods 3D radial ultrashort echo time was implemented on a 3T scanner to investigate the effects of: (1) limited field-of-view excitation, (2) variable density readouts, and (3) radial oversampling. Improvements in noise performance and spatial resolution were assessed through simulation and phantom studies. Their effects on lung and airway visualization in five healthy male human subjects (mean age 32 years) were compared qualitatively through blinded ordinal scoring by two cardiothoracic radiologists using a nonparametric Friedman test (P < 0.05). Relative signal difference between endobronchial air and adjacent lung tissue, normalized to nearby vessel, was used as a surrogate for lung tissue signal. Quantitative measures were compared using the paired Student's t-test (P < 0.05). Finally, clinical feasibility was investigated in a patient with interstitial fibrosis. Results Simulation and phantom studies showed up to 67% improvement in SNR and reduced blurring for short T2* species using all three optimizations. In vivo images showed decreased artifacts and improved lung tissue and airway visualization both qualitatively and quantitatively. Conclusion The use of limited field-of-view excitation, variable readout gradients, and radial oversampling significantly improve the technical quality of 3D radial ultrashort echo time lung images. PMID:23213020

  8. Prestack reverse time migration for 3D marine reflection seismic data

    SciTech Connect

    Jang, Seonghyung; Kim, Taeyoun

    2015-03-10

    Prestack reverse time migration (RTM) is a method for imaging the subsurface using the inner product of wavefield extrapolation in shot domain and in receiver domain. It is well known that RTM is better for preserving amplitudes and phases than other prestack migrations. Since 3D seismic data is huge data volume and it needs heavy computing works, it requires parallel computing in order to have a meaningful depth image of the 3D subsurface. We implemented a parallelized version of 3D RTM for prestack depth migration. The results of numerical example for 3D SEG/EAGE salt model showed good agreement with the original geological model. We applied RTM to offshore 3D seismic reflection data. The study area is 12 × 25 km with 120 survey lines. Shot and receiver spacing is 25 m and 12.5 m. The line spacing is 100 m. Shot gathers were preprocessed to enhance signal to noise ratio and velocity model was calculated from conventional stack velocity. Both of them were used to obtain 3D image using RTM. The results show reasonable subsurface image.

  9. 3D seismic data reconstruction based on complex-valued curvelet transform in frequency domain

    NASA Astrophysics Data System (ADS)

    Zhang, Hua; Chen, Xiaohong; Li, Hongxing

    2015-02-01

    Traditional seismic data sampling must follow the Nyquist Sampling Theorem. However, the field data acquisition may not meet the sampling criteria due to missing traces or limits in exploration cost, causing a prestack data reconstruction problem. Recently researchers have proposed many useful methods to regularize the seismic data. In this paper, a 3D seismic data reconstruction method based on the Projections Onto Convex Sets (POCS) algorithm and a complex-valued curvelet transform (CCT) has been introduced in the frequency domain. In order to improve reconstruction efficiency and reduce the computation time, the seismic data are transformed from the t-x-y domain to the f-x-y domain and the data reconstruction is processed for every frequency slice during the reconstruction process. The selection threshold parameter is important for reconstruction efficiency for each iteration, therefore an exponential square root decreased (ESRD) threshold is proposed. The experimental results show that the ESRD threshold can greatly reduce iterations and improve reconstruction efficiency compared to the other thresholds for the same reconstruction result. We also analyze the antinoise ability of the CCT-based POCS reconstruction method. The example studies on synthetic and real marine seismic data showed that our proposed method is more efficient and applicable.

  10. Reconstructing photorealistic 3D models from image sequence using domain decomposition method

    NASA Astrophysics Data System (ADS)

    Xiong, Hanwei; Pan, Ming; Zhang, Xiangwei

    2009-11-01

    In the fields of industrial design, artistic design and heritage conservation, physical objects are usually digitalized by reverse engineering through some 3D scanning methods. Structured light and photogrammetry are two main methods to acquire 3D information, and both are expensive. Even if these expensive instruments are used, photorealistic 3D models are seldom available. In this paper, a new method to reconstruction photorealistic 3D models using a single camera is proposed. A square plate glued with coded marks is used to place the objects, and a sequence of about 20 images is taken. From the coded marks, the images are calibrated, and a snake algorithm is used to segment object from the background. A rough 3d model is obtained using shape from silhouettes algorithm. The silhouettes are decomposed into a combination of convex curves, which are used to partition the rough 3d model into some convex mesh patches. For each patch, the multi-view photo consistency constraints and smooth regulations are expressed as a finite element formulation, which can be resolved locally, and the information can be exchanged along the patches boundaries. The rough model is deformed into a fine 3d model through such a domain decomposition finite element method. The textures are assigned to each element mesh, and a photorealistic 3D model is got finally. A toy pig is used to verify the algorithm, and the result is exciting.

  11. Real-time 3D change detection of IEDs

    NASA Astrophysics Data System (ADS)

    Wathen, Mitch; Link, Norah; Iles, Peter; Jinkerson, John; Mrstik, Paul; Kusevic, Kresimir; Kovats, David

    2012-06-01

    Road-side bombs are a real and continuing threat to soldiers in theater. CAE USA recently developed a prototype Volume based Intelligence Surveillance Reconnaissance (VISR) sensor platform for IED detection. This vehicle-mounted, prototype sensor system uses a high data rate LiDAR (1.33 million range measurements per second) to generate a 3D mapping of roadways. The mapped data is used as a reference to generate real-time change detection on future trips on the same roadways. The prototype VISR system is briefly described. The focus of this paper is the methodology used to process the 3D LiDAR data, in real-time, to detect small changes on and near the roadway ahead of a vehicle traveling at moderate speeds with sufficient warning to stop the vehicle at a safe distance from the threat. The system relies on accurate navigation equipment to geo-reference the reference run and the change-detection run. Since it was recognized early in the project that detection of small changes could not be achieved with accurate navigation solutions alone, a scene alignment algorithm was developed to register the reference run with the change detection run prior to applying the change detection algorithm. Good success was achieved in simultaneous real time processing of scene alignment plus change detection.

  12. Computational Identification of Genomic Features That Influence 3D Chromatin Domain Formation

    PubMed Central

    Mourad, Raphaël; Cuvier, Olivier

    2016-01-01

    Recent advances in long-range Hi-C contact mapping have revealed the importance of the 3D structure of chromosomes in gene expression. A current challenge is to identify the key molecular drivers of this 3D structure. Several genomic features, such as architectural proteins and functional elements, were shown to be enriched at topological domain borders using classical enrichment tests. Here we propose multiple logistic regression to identify those genomic features that positively or negatively influence domain border establishment or maintenance. The model is flexible, and can account for statistical interactions among multiple genomic features. Using both simulated and real data, we show that our model outperforms enrichment test and non-parametric models, such as random forests, for the identification of genomic features that influence domain borders. Using Drosophila Hi-C data at a very high resolution of 1 kb, our model suggests that, among architectural proteins, BEAF-32 and CP190 are the main positive drivers of 3D domain borders. In humans, our model identifies well-known architectural proteins CTCF and cohesin, as well as ZNF143 and Polycomb group proteins as positive drivers of domain borders. The model also reveals the existence of several negative drivers that counteract the presence of domain borders including P300, RXRA, BCL11A and ELK1. PMID:27203237

  13. Laplace-domain waveform modeling and inversion for the 3D acoustic-elastic coupled media

    NASA Astrophysics Data System (ADS)

    Shin, Jungkyun; Shin, Changsoo; Calandra, Henri

    2016-06-01

    Laplace-domain waveform inversion reconstructs long-wavelength subsurface models by using the zero-frequency component of damped seismic signals. Despite the computational advantages of Laplace-domain waveform inversion over conventional frequency-domain waveform inversion, an acoustic assumption and an iterative matrix solver have been used to invert 3D marine datasets to mitigate the intensive computing cost. In this study, we develop a Laplace-domain waveform modeling and inversion algorithm for 3D acoustic-elastic coupled media by using a parallel sparse direct solver library (MUltifrontal Massively Parallel Solver, MUMPS). We precisely simulate a real marine environment by coupling the 3D acoustic and elastic wave equations with the proper boundary condition at the fluid-solid interface. In addition, we can extract the elastic properties of the Earth below the sea bottom from the recorded acoustic pressure datasets. As a matrix solver, the parallel sparse direct solver is used to factorize the non-symmetric impedance matrix in a distributed memory architecture and rapidly solve the wave field for a number of shots by using the lower and upper matrix factors. Using both synthetic datasets and real datasets obtained by a 3D wide azimuth survey, the long-wavelength component of the P-wave and S-wave velocity models is reconstructed and the proposed modeling and inversion algorithm are verified. A cluster of 80 CPU cores is used for this study.

  14. Global regular solutions for the 3D Kawahara equation posed on unbounded domains

    NASA Astrophysics Data System (ADS)

    Larkin, Nikolai A.; Simões, Márcio Hiran

    2016-08-01

    An initial boundary value problem for the 3D Kawahara equation posed on a channel-type domain was considered. The existence and uniqueness results for global regular solutions as well as exponential decay of small solutions in the H 2-norm were established.

  15. Global regular solutions for the 3D Zakharov-Kuznetsov equation posed on unbounded domains

    NASA Astrophysics Data System (ADS)

    Larkin, N. A.

    2015-09-01

    An initial-boundary value problem for the 3D Zakharov-Kuznetsov equation posed on unbounded domains is considered. Existence and uniqueness of a global regular solution as well as exponential decay of the H2-norm for small initial data are proven.

  16. 3-D tracking in a miniature time projection chamber

    NASA Astrophysics Data System (ADS)

    Vahsen, S. E.; Hedges, M. T.; Jaegle, I.; Ross, S. J.; Seong, I. S.; Thorpe, T. N.; Yamaoka, J.; Kadyk, J. A.; Garcia-Sciveres, M.

    2015-07-01

    The three-dimensional (3-D) detection of millimeter-scale ionization trails is of interest for detecting nuclear recoils in directional fast neutron detectors and in direction-sensitive searches for weakly interacting massive particles (WIMPs), which may constitute the Dark Matter of the universe. We report on performance characterization of a miniature gas target Time Projection Chamber (TPC) where the drift charge is avalanche-multiplied with Gas Electron Multipliers (GEMs) and detected with the ATLAS FE-I3 Pixel Application Specific Integrated Circuit (ASIC). We report on measurements of gain, gain resolution, point resolution, diffusion, angular resolution, and energy resolution with low-energy X-rays, cosmic rays, and alpha particles, using the gases Ar:CO2 (70:30) and He:CO2 (70:30) at atmospheric pressure. We discuss the implications for future, larger directional neutron and Dark Matter detectors. With an eye to designing and selecting components for these, we generalize our results into analytical expressions for detector performance whenever possible. We conclude by demonstrating the 3-D directional detection of a fast neutron source.

  17. Real time 3D scanner: investigations and results

    NASA Astrophysics Data System (ADS)

    Nouri, Taoufik; Pflug, Leopold

    1993-12-01

    This article presents a concept of reconstruction of 3-D objects using non-invasive and touch loss techniques. The principle of this method is to display parallel interference optical fringes on an object and then to record the object under two angles of view. According to an appropriated treatment one reconstructs the 3-D object even when the object has no symmetrical plan. The 3-D surface data is available immediately in digital form for computer- visualization and for analysis software tools. The optical set-up for recording the 3-D object, the 3-D data extraction and treatment, as well as the reconstruction of the 3-D object are reported and commented on. This application is dedicated for reconstructive/cosmetic surgery, CAD, animation and research purposes.

  18. 3D topology and arrangement of proteins inside ceramide-rich domains

    NASA Astrophysics Data System (ADS)

    Imhäuser, Christian; Gulbins, Heike; Gulbins, Erich; Lipinski, Hans-Gerd

    2010-04-01

    Clustering of receptor and signalling molecules (such as CD95 or CD40) within ceramide-enriched membrane domains results in a very high density of these proteins facilitating activation of associated enzymes, the exclusion of inhibitory molecules and/or the recruitment of further signalling molecules to transmit the signal into the cells. However, at present the mechanisms of receptor clustering and the exact distribution of proteins within the ceramide-enriched domains are unknown. Therefore, we generated digital images from anti-CD95 stimulated JYcells that were stained with FITC-coupled anti-ceramide and Cy3-labelled anti-CD95 antibodies. We developed image processing methods to determine the spatial distribution of proteins in ceramide-enriched membrane domains and visualized them by volume rendering and surface models. After image preprocessing with appropriate filters for contrast enhancement, noise reduction and logarithmic scaling, 3D models were generated using adapted volume and surface reconstruction. To detect the colocalization of CD95 and ceramide molecules we developed several different methods rasterizing 3D data of each channel into cells and counting intensity values above a specified colour threshold value. The colocalization voxel was set either by normalized product of totals (product intensity) or depending on binarization. In addition, a cross-covariance function to quantify the colocalization was determined and embedded as a 3D object. These computerized techniques allowed for a quantitative analysis of the spatial arrangement of proteins in ceramide-rich domains of living cells.

  19. Reduced Scan Time 3D FLAIR using Modulated Inversion and Repetition Time

    PubMed Central

    Gai, Neville D.; Butman, John A.

    2014-01-01

    Purpose To design and evaluate a new reduced scan time 3D FLuid Attenuated Inversion Recovery (FLAIR) sequence. Materials and Methods The 3D FLAIR sequence was modified so that the repetition time was modulated in a predetermined smooth fashion (3D mFLAIR). Inversion times were adjusted accordingly to maintain CSF suppression. Simulations were performed to determine SNR for gray matter (GM), white matter (WM) and CSF. Fourteen volunteers were imaged using the modified and product sequence. SNR measurements were performed in GM, WM and CSF. Mean value and the 95% confidence interval ([CI]) were assessed. Scan time for the 3D FLAIR and 3D mFLAIR sequences was measured. Results There was no statistically significant difference in the SNR measured in GM (P value = 0.5; mean SNR = 42.8 [CI]: 38.2-45.5 vs 42.2 [CI]: 38.3-46.1 for 3D FLAIR and 3D mFLAIR, respectively) and WM (P value = 0.25; mean SNR = 32.1 [CI]: 30.3-33.8 vs 32.9 [CI]: 31.1-34.7). Scan time reduction greater than 30% was achieved for the given parameter set with the 3D mFLAIR sequence. Conclusion Scan time for 3D FLAIR can be effectively reduced by modulating repetition and inversion time in a predetermined fashion while maintaining the SNR and CNR of a constant TR sequence. PMID:24979311

  20. 3D versus 2D domain wall interaction in ideal and rough nanowires

    NASA Astrophysics Data System (ADS)

    Pivano, A.; Dolocan, Voicu O.

    2015-11-01

    The interaction between transverse magnetic domain walls (TDWs) in planar (2D) and cylindrical (3D) nanowires is examined using micromagnetic simulations. We show that in perfect and surface deformed wires the free TDWs behave differently, as the 3D TDWs combine into metastable states with average lifetimes of 300 ns depending on roughness, while the 2D TDWs do not due to 2D shape anisotropy. When the 2D and 3D TDWs are pinned at artificial constrictions, they behave similarly as they interact mainly through the dipolar field. This magnetostatic interaction is well described by the point charge model with multipole expansion. In surface deformed wires with artificial constrictions, the interaction becomes more complex as the depinning field decreases and dynamical pinning can lead to local resonances. This can strongly influence the control of TDWs in DW-based devices.

  1. Automated multilayer segmentation and characterization in 3D spectral-domain optical coherence tomography images

    NASA Astrophysics Data System (ADS)

    Hu, Zhihong; Wu, Xiaodong; Hariri, Amirhossein; Sadda, SriniVas R.

    2013-03-01

    Spectral-domain optical coherence tomography (SD-OCT) is a 3-D imaging technique, allowing direct visualization of retinal morphology and architecture. The various layers of the retina may be affected differentially by various diseases. In this study, an automated graph-based multilayer approach was developed to sequentially segment eleven retinal surfaces including the inner retinal bands to the outer retinal bands in normal SD-OCT volume scans at three different stages. For stage 1, the four most detectable and/or distinct surfaces were identified in the four-times-downsampled images and were used as a priori positional information to limit the graph search for other surfaces at stage 2. Eleven surfaces were then detected in the two-times-downsampled images at stage 2, and refined in the original image space at stage 3 using the graph search integrating the estimated morphological shape models. Twenty macular SD-OCT (Heidelberg Spectralis) volume scans from 20 normal subjects (one eye per subject) were used in this study. The overall mean and absolute mean differences in border positions between the automated and manual segmentation for all 11 segmented surfaces were -0.20 +/- 0.53 voxels (-0.76 +/- 2.06 μm) and 0.82 +/- 0.64 voxels (3.19 +/- 2.46 μm). Intensity and thickness properties in the resultant retinal layers were investigated. This investigation in normal subjects may provide a comparative reference for subsequent investigations in eyes with disease.

  2. Simulation domain size requirements for elastic response of 3D polycrystalline materials

    NASA Astrophysics Data System (ADS)

    Ozturk, Tugce; Stein, Clayton; Pokharel, Reeju; Hefferan, Christopher; Tucker, Harris; Jha, Sushant; John, Reji; Lebensohn, Ricardo A.; Kenesei, Peter; Suter, Robert M.; Rollett, Anthony D.

    2016-01-01

    A fast Fourier transform (FFT) based spectral algorithm is used to compute the full field mechanical response of polycrystalline microstructures. The field distributions in a specific region are used to determine the sensitivity of the method to the number of surrounding grains through quantification of the divergence of the field values from the largest simulation domain, as successively smaller surrounding volumes are included in the simulation. The analysis considers a mapped 3D structure where the location of interest is taken to be a particular pair of surface grains that enclose a small fatigue crack, and synthetically created statistically representative microstructures to further investigate the effect of anisotropy, loading condition, loading direction, and texture. The synthetic structures are generated via DREAM3D and the measured material is a cyclically loaded, Ni-based, low solvus high refractory (LSHR) superalloy that was characterized via 3D high energy x-ray diffraction microscopy (HEDM). Point-wise comparison of distributions in the grain pairs shows that, in order to obtain a Pearson correlation coefficient larger than 99%, the domain must extend to at least the third nearest neighbor. For an elastic FFT calculation, the stress-strain distributions are not sensitive to the shape of the domain. The main result is that convergence can be specified in terms of the number of grains surrounding a region of interest.

  3. 3D virtual colonoscopy with real-time volume rendering

    NASA Astrophysics Data System (ADS)

    Wan, Ming; Li, Wei J.; Kreeger, Kevin; Bitter, Ingmar; Kaufman, Arie E.; Liang, Zhengrong; Chen, Dongqing; Wax, Mark R.

    2000-04-01

    In our previous work, we developed a virtual colonoscopy system on a high-end 16-processor SGI Challenge with an expensive hardware graphics accelerator. The goal of this work is to port the system to a low cost PC in order to increase its availability for mass screening. Recently, Mitsubishi Electric has developed a volume-rendering PC board, called VolumePro, which includes 128 MB of RAM and vg500 rendering chip. The vg500 chip, based on Cube-4 technology, can render a 2563 volume at 30 frames per second. High image quality of volume rendering inside the colon is guaranteed by the full lighting model and 3D interpolation supported by the vg500 chip. However, the VolumePro board is lacking some features required by our interactive colon navigation. First, VolumePro currently does not support perspective projection which is paramount for interior colon navigation. Second, the patient colon data is usually much larger than 2563 and cannot be rendered in real-time. In this paper, we present our solutions to these problems, including simulated perspective projection and axis aligned boxing techniques, and demonstrate the high performance of our virtual colonoscopy system on low cost PCs.

  4. 3D homogeneity study in PMMA layers using a Fourier domain OCT system

    NASA Astrophysics Data System (ADS)

    Briones-R., Manuel de J.; Torre-Ibarra, Manuel H. De La; Tavera, Cesar G.; Luna H., Juan M.; Mendoza-Santoyo, Fernando

    2016-11-01

    Micro-metallic particles embedded in polymers are now widely used in several industrial applications in order to modify the mechanical properties of the bulk. A uniform distribution of these particles inside the polymers is highly desired for instance, when a biological backscattering is simulated or a bio-framework is designed. A 3D Fourier domain optical coherence tomography system to detect the polymer's internal homogeneity is proposed. This optical system has a 2D camera sensor array that records a fringe pattern used to reconstruct with a single shot the tomographic image of the sample. The system gathers the full 3D tomographic and optical phase information during a controlled deformation by means of a motion linear stage. This stage avoids the use of expensive tilting stages, which in addition are commonly controlled by piezo drivers. As proof of principle, a series of different deformations were proposed to detect the uniform or non-uniform internal deposition of copper micro particles. The results are presented as images coming from the 3D tomographic micro reconstruction of the samples, and the 3D optical phase information that identifies the in-homogeneity regions within the Poly methyl methacrylate (PMMA) volume.

  5. Extra Dimensions: 3D and Time in PDF Documentation

    SciTech Connect

    Graf, N.A.; /SLAC

    2012-04-11

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide, non-technical audience. We discuss how the field of radiation imaging could benefit from incorporating full 3D information about not only the detectors, but also the results of the experimental analyses, in its electronic publications. In this article, we present examples drawn from high-energy physics, mathematics and molecular biology which take advantage of this functionality. We demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input.

  6. Extra dimensions: 3D and time in PDF documentation

    NASA Astrophysics Data System (ADS)

    Graf, N. A.

    2011-01-01

    Experimental science is replete with multi-dimensional information which is often poorly represented by the two dimensions of presentation slides and print media. Past efforts to disseminate such information to a wider audience have failed for a number of reasons, including a lack of standards which are easy to implement and have broad support. Adobe's Portable Document Format (PDF) has in recent years become the de facto standard for secure, dependable electronic information exchange. It has done so by creating an open format, providing support for multiple platforms and being reliable and extensible. By providing support for the ECMA standard Universal 3D (U3D) file format in its free Adobe Reader software, Adobe has made it easy to distribute and interact with 3D content. By providing support for scripting and animation, temporal data can also be easily distributed to a wide, non-technical audience. We discuss how the field of radiation imaging could benefit from incorporating full 3D information about not only the detectors, but also the results of the experimental analyses, in its electronic publications. In this article, we present examples drawn from high-energy physics, mathematics and molecular biology which take advantage of this functionality. We demonstrate how 3D detector elements can be documented, using either CAD drawings or other sources such as GEANT visualizations as input.

  7. 3D seismic reverse time migration on GPGPU

    NASA Astrophysics Data System (ADS)

    Liu, Guofeng; Liu, Yaning; Ren, Li; Meng, Xiaohong

    2013-09-01

    Reverse time migration (RTM) is a powerful seismic imaging method for the interpretation of steep-dips and subsalt regions; however, implementation of the RTM method is computationally expensive. In this paper, we present a fast and computationally inexpensive implementation of RTM using a NVIDIA general purpose graphic processing unit (GPGPU) powered with Compute Unified Device Architecture (CUDA). To accomplish this, we introduced a random velocity boundary in the source propagation kernel. By creating a random velocity layer at the left, right, and bottom boundaries, the wave fields that encounter the boundary regions are pseudo-randomized. Reflections off the random layers have minimal coherent correlation in the reverse direction. This process eliminates the need to write the wave fields to a disk, which is important when using a GPU because of the limited bandwidth of the PCI-E that is connected to the CPU and GPU. There are four GPU kernels in the code: shot, receiver, modeling, and imaging. The shot and receiver insertion kernels are simple and are computed using a GPU because the wave fields reside in GPU's memory. The modeling kernel is computed using Micikevicius's tiling method, which uses shared memory to improve bandwidth usage in 2D and 3D finite difference problems. In the imaging kernel, we also use this tiling method. A Tesla C2050 GPU with 4 GB memory and 480 stream processing units was used to test the code. The shot and receiver modeling kernel occupancy achieved 85%, and the imaging kernel occupancy was 100%. This means that the code achieved a good level of optimization. A salt model test verified the correct and effective implementation of the GPU RTM code.

  8. Gust Acoustics Computation with a Space-Time CE/SE Parallel 3D Solver

    NASA Technical Reports Server (NTRS)

    Wang, X. Y.; Himansu, A.; Chang, S. C.; Jorgenson, P. C. E.; Reddy, D. R. (Technical Monitor)

    2002-01-01

    The benchmark Problem 2 in Category 3 of the Third Computational Aero-Acoustics (CAA) Workshop is solved using the space-time conservation element and solution element (CE/SE) method. This problem concerns the unsteady response of an isolated finite-span swept flat-plate airfoil bounded by two parallel walls to an incident gust. The acoustic field generated by the interaction of the gust with the flat-plate airfoil is computed by solving the 3D (three-dimensional) Euler equations in the time domain using a parallel version of a 3D CE/SE solver. The effect of the gust orientation on the far-field directivity is studied. Numerical solutions are presented and compared with analytical solutions, showing a reasonable agreement.

  9. System crosstalk measurement of a time-sequential 3D display using ideal shutter glasses

    NASA Astrophysics Data System (ADS)

    Chen, Fu-Hao; Huang, Kuo-Chung; Lin, Lang-Chin; Chou, Yi-Heng; Lee, Kuen

    2011-03-01

    The market of stereoscopic 3D TV grows up fast recently; however, for 3D TV really taking off, the interoperability of shutter glasses (SG) to view different TV sets must be solved, so we developed a measurement method with ideal shutter glasses (ISG) to separate time-sequential stereoscopic displays and SG. For measuring the crosstalk from time-sequential stereoscopic 3D displays, the influences from SG must be eliminated. The advantages are that the sources to crosstalk are distinguished, and the interoperability of SG is broadened. Hence, this paper proposed ideal shutter glasses, whose non-ideal properties are eliminated, as a platform to evaluate the crosstalk purely from the display. In the ISG method, the illuminance of the display was measured in time domain to analyze the system crosstalk SCT of the display. In this experiment, the ISG method was used to measure SCT with a high-speed-response illuminance meter. From the time-resolved illuminance signals, the slow time response of liquid crystal leading to SCT is visualized and quantified. Furthermore, an intriguing phenomenon that SCT measured through SG increases with shortening view distance was observed, and it may arise from LC leakage of the display and shutter leakage at large view angle. Thus, we measured how LC and shutter leakage depending on view angle and verified our argument. Besides, we used the ISG method to evaluate two displays.

  10. 3D domain swapping in a chimeric c-Src SH3 domain takes place through two hinge loops.

    PubMed

    Cámara-Artigas, Ana; Martínez-Rodríguez, Sergio; Ortiz-Salmerón, Emilia; Martín-García, José M

    2014-04-01

    In the Src Homology 3 domain (SH3) the RT and n-Src loops form a pocket that accounts for the specificity and affinity in binding of proline rich motifs (PRMs), while the distal and diverging turns play a key role in the folding of the protein. We have solved the structure of a chimeric mutant c-Src-SH3 domain where specific residues at the RT- and n-Src-loops have been replaced by those present in the corresponding Abl-SH3 domain. Crystals of the chimeric protein show a single molecule in the asymmetric unit, which appears in an unfolded-like structure that upon generation of the symmetry related molecules reveals the presence of a domain swapped dimer where both, RT- and n-Src loops, act as hinge loops. In contrast, the fold of the diverging type II β-turn and the distal loop are well conserved. Our results are the first evidence for the presence of a structured diverging type II β-turn in an unfolded-like intermediate of the c-Src-SH3 domain, which can be stabilized by interactions from the β-strands of the same polypeptide chain or from a neighboring one. Futhermore, this crystallographic structure opens a unique opportunity to study the effect of the amino acid sequence of the hinge loops on the 3D domain swapping process of c-Src-SH3. PMID:24556574

  11. Time-domain imaging

    NASA Technical Reports Server (NTRS)

    Tolliver, C. L.

    1989-01-01

    The quest for the highest resolution microwave imaging and principle of time-domain imaging has been the primary motivation for recent developments in time-domain techniques. With the present technology, fast time varying signals can now be measured and recorded both in magnitude and in-phase. It has also enhanced our ability to extract relevant details concerning the scattering object. In the past, the interface of object geometry or shape for scattered signals has received substantial attention in radar technology. Various scattering theories were proposed to develop analytical solutions to this problem. Furthermore, the random inversion, frequency swept holography, and the synthetic radar imaging, have two things in common: (1) the physical optic far-field approximation, and (2) the utilization of channels as an extra physical dimension, were also advanced. Despite the inherent vectorial nature of electromagnetic waves, these scalar treatments have brought forth some promising results in practice with notable examples in subsurface and structure sounding. The development of time-domain techniques are studied through the theoretical aspects as well as experimental verification. The use of time-domain imaging for space robotic vision applications has been suggested.

  12. Monitoring adipose-derived stem cells within 3D carrier by combined dielectric spectroscopy and spectral domain optical coherence topography

    NASA Astrophysics Data System (ADS)

    Bagnaninchi, P. O.

    2010-02-01

    Monitoring non-invasively the cellular events in three dimensional carriers is a major challenge for tissue engineering and regenerative medicine that prevents time-lapsed studies over large population of sample. The potential of optical coherence tomography has been demonstrated to assess tissue formation within porous matrices. In this study we explore the combination of dielectric spectroscopy (DS) and spectral domain optical coherence tomography (SDOCT) to quality assess ADSCs loaded in three dimensional carriers. A SDOCT (930nm, FWHM 90nm) was combined to an open ended coaxial probe connected to material analyser, and broadband measurements between 20MHz and 1GHz were synchronized with Labview. Both ADSCs maintained in undifferentiated state within 3D carrier and induced towards osteoblasts were monitored with this multimodality technique and their DS spectra were acquired at high cell concentration simultaneously to 3D imaging. This multimodality technique will be instrumental to assess non-invasively cell loaded carriers for cell therapy.

  13. Real-Time Camera Guidance for 3d Scene Reconstruction

    NASA Astrophysics Data System (ADS)

    Schindler, F.; Förstner, W.

    2012-07-01

    We propose a framework for operator guidance during the image acquisition process for reliable multi-view stereo reconstruction. Goal is to achieve full coverage of the object and sufficient overlap. Multi-view stereo is a commonly used method to reconstruct both camera trajectory and 3D object shape. After determining an initial solution, a globally optimal reconstruction is usually obtained by executing a bundle adjustment involving all images. Acquiring suitable images, however, still requires an experienced operator to ensure accuracy and completeness of the final solution. We propose an interactive framework for guiding unexperienced users or possibly an autonomous robot. Using approximate camera orientations and object points we estimate point uncertainties within a sliding bundle adjustment and suggest appropriate camera movements. A visual feedback system communicates the decisions to the user in an intuitive way. We demonstrate the suitability of our system with a virtual image acquisition simulation as well as in real-world scenarios. We show that when following the camera movements suggested by our system, the proposed framework is able to generate good approximate values for the bundle adjustment, leading to accurate results compared to ground truth after few iterations. Possible applications are non-professional 3D acquisition systems on low-cost platforms like mobile phones, autonomously navigating robots as well as online flight planning of unmanned aerial vehicles.

  14. Future enhancements to 3D printing and real time production

    NASA Astrophysics Data System (ADS)

    Landa, Joseph; Jenkins, Jeffery; Wu, Jerry; Szu, Harold

    2014-05-01

    The cost and scope of additive printing machines range from several hundred to hundreds of thousands of dollars. For the extra money, one can get improvements in build size, selection of material properties, resolution, and consistency. However, temperature control during build and fusing predicts outcome and protects the IP by large high cost machines. Support material options determine geometries that can be accomplished which drives cost and complexity of printing heads. Historically, 3D printers have been used for design and prototyping efforts. Recent advances and cost reduction sparked new interest in developing printed products and consumables such as NASA who is printing food, printing consumer parts (e.g. cell phone cases, novelty toys), making tools and fixtures in manufacturing, and recursively print a self-similar printer (c.f. makerbot). There is a near term promise of the capability to print on demand products at the home or office... directly from the printer to use.

  15. Integration of real-time 3D capture, reconstruction, and light-field display

    NASA Astrophysics Data System (ADS)

    Zhang, Zhaoxing; Geng, Zheng; Li, Tuotuo; Pei, Renjing; Liu, Yongchun; Zhang, Xiao

    2015-03-01

    Effective integration of 3D acquisition, reconstruction (modeling) and display technologies into a seamless systems provides augmented experience of visualizing and analyzing real objects and scenes with realistic 3D sensation. Applications can be found in medical imaging, gaming, virtual or augmented reality and hybrid simulations. Although 3D acquisition, reconstruction, and display technologies have gained significant momentum in recent years, there seems a lack of attention on synergistically combining these components into a "end-to-end" 3D visualization system. We designed, built and tested an integrated 3D visualization system that is able to capture in real-time 3D light-field images, perform 3D reconstruction to build 3D model of the objects, and display the 3D model on a large autostereoscopic screen. In this article, we will present our system architecture and component designs, hardware/software implementations, and experimental results. We will elaborate on our recent progress on sparse camera array light-field 3D acquisition, real-time dense 3D reconstruction, and autostereoscopic multi-view 3D display. A prototype is finally presented with test results to illustrate the effectiveness of our proposed integrated 3D visualization system.

  16. Robust and Blind 3D Mesh Watermarking in Spatial Domain Based on Faces Categorization and Sorting

    NASA Astrophysics Data System (ADS)

    Molaei, Amir Masoud; Ebrahimnezhad, Hossein; Sedaaghi, Mohammad Hossein

    2016-06-01

    In this paper, a 3D watermarking algorithm in spatial domain is presented with blind detection. In the proposed method, a negligible visual distortion is observed in host model. Initially, a preprocessing is applied on the 3D model to make it robust against geometric transformation attacks. Then, a number of triangle faces are determined as mark triangles using a novel systematic approach in which faces are categorized and sorted robustly. In order to enhance the capability of information retrieval by attacks, block watermarks are encoded using Reed-Solomon block error-correcting code before embedding into the mark triangles. Next, the encoded watermarks are embedded in spherical coordinates. The proposed method is robust against additive noise, mesh smoothing and quantization attacks. Also, it is stout next to geometric transformation, vertices and faces reordering attacks. Moreover, the proposed algorithm is designed so that it is robust against the cropping attack. Simulation results confirm that the watermarked models confront very low distortion if the control parameters are selected properly. Comparison with other methods demonstrates that the proposed method has good performance against the mesh smoothing attacks.

  17. Domain Decomposition PN Solutions to the 3D Transport Benchmark over a Range in Parameter Space

    NASA Astrophysics Data System (ADS)

    Van Criekingen, S.

    2014-06-01

    The objectives of this contribution are twofold. First, the Domain Decomposition (DD) method used in the parafish parallel transport solver is re-interpreted as a Generalized Schwarz Splitting as defined by Tang [SIAM J Sci Stat Comput, vol.13 (2), pp. 573-595, 1992]. Second, parafish provides spherical harmonic (i.e., PN) solutions to the NEA benchmark suite for 3D transport methods and codes over a range in parameter space. To the best of the author's knowledge, these are the first spherical harmonic solutions provided for this demanding benchmark suite. They have been obtained using 512 CPU cores of the JuRoPa machine installed at the Jülich Computing Center (Germany).

  18. Multifocal multiphoton excitation and time correlated single photon counting detection for 3-D fluorescence lifetime imaging.

    PubMed

    Kumar, S; Dunsby, C; De Beule, P A A; Owen, D M; Anand, U; Lanigan, P M P; Benninger, R K P; Davis, D M; Neil, M A A; Anand, P; Benham, C; Naylor, A; French, P M W

    2007-10-01

    We report a multifocal multiphoton time-correlated single photon counting (TCSPC) fluorescence lifetime imaging (FLIM) microscope system that uses a 16 channel multi-anode PMT detector. Multiphoton excitation minimizes out-of-focus photobleaching, multifocal excitation reduces non-linear in-plane photobleaching effects and TCSPC electronics provide photon-efficient detection of the fluorescence decay profile. TCSPC detection is less prone to bleaching- and movement-induced artefacts compared to wide-field time-gated or frequency-domain FLIM. This microscope is therefore capable of acquiring 3-D FLIM images at significantly increased speeds compared to single beam multiphoton microscopy and we demonstrate this with live cells expressing a GFP tagged protein. We also apply this system to time-lapse FLIM of NAD(P)H autofluorescence in single live cells and report measurements on the change in the fluorescence decay profile following the application of a known metabolic inhibitor. PMID:19550524

  19. An Automatic 3D Mesh Generation Method for Domains with Multiple Materials.

    PubMed

    Zhang, Yongjie; Hughes, Thomas J R; Bajaj, Chandrajit L

    2010-01-01

    This paper describes an automatic and efficient approach to construct unstructured tetrahedral and hexahedral meshes for a composite domain made up of heterogeneous materials. The boundaries of these material regions form non-manifold surfaces. In earlier papers, we developed an octree-based isocontouring method to construct unstructured 3D meshes for a single-material (homogeneous) domain with manifold boundary. In this paper, we introduce the notion of a material change edge and use it to identify the interface between two or several different materials. A novel method to calculate the minimizer point for a cell shared by more than two materials is provided, which forms a non-manifold node on the boundary. We then mesh all the material regions simultaneously and automatically while conforming to their boundaries directly from volumetric data. Both material change edges and interior edges are analyzed to construct tetrahedral meshes, and interior grid points are analyzed for proper hexahedral mesh construction. Finally, edge-contraction and smoothing methods are used to improve the quality of tetrahedral meshes, and a combination of pillowing, geometric flow and optimization techniques is used for hexahedral mesh quality improvement. The shrink set of pillowing schemes is defined automatically as the boundary of each material region. Several application results of our multi-material mesh generation method are also provided. PMID:20161555

  20. FDFD: A 3D Finite-Difference Frequency-Domain Code for Electromagnetic Induction Tomography

    NASA Astrophysics Data System (ADS)

    Champagne, Nathan J.; Berryman, James G.; Buettner, H. Michael

    2001-07-01

    A new 3D code for electromagnetic induction tomography with intended applications to environmental imaging problems has been developed. The approach consists of calculating the fields within a volume using an implicit finite-difference frequency-domain formulation. The volume is terminated by an anisotropic perfectly matched layer region that simulates an infinite domain by absorbing outgoing waves. Extensive validation of this code has been done using analytical and semianalytical results from other codes, and some of those results are presented in this paper. The new code is written in Fortran 90 and is designed to be easily parallelized. Finally, an adjoint field method of data inversion, developed in parallel for solving the fully nonlinear inverse problem for electrical conductivity imaging (e.g., for mapping underground conducting plumes), uses this code to provide solvers for both forward and adjoint fields. Results obtained from this inversion method for high-contrast media are encouraging and provide a significant improvement over those obtained from linearized inversion methods.

  1. GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 1: Theory and method

    NASA Technical Reports Server (NTRS)

    Shih, T. I.-P.; Bailey, R. T.; Nguyen, H. L.; Roelke, R. J.

    1990-01-01

    An efficient computer program, called GRID2D/3D was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no

  2. 3D micro profile measurement with the method of spatial frequency domain analysis

    NASA Astrophysics Data System (ADS)

    Xu, Yongxiang

    2015-10-01

    3D micro profiles are often needed for measurement in many fields, e.g., binary optics, electronic industry, mechanical manufacturing, aeronautic and space industry, etc. In the case where height difference between two neighboring points of a test profile is equal to or greater than λ / 4, microscopic interferometry based on laser source will no longer be applicable because of the uncertainty in phase unwrapping. As white light possesses the characteristic of interference length approximate to zero, applying it for micro profilometry can avoid the trouble and can yield accurate results. Using self-developed Mirau-type scanning interference microscope, a step-like sample was tested twice, with 128 scanning interferograms recorded for each test. To process each set of the interferograms, the method of spatial frequency domain analysis was adopted. That is, for each point, by use of Furrier transform, white-light interference intensities were decomposed in spatial frequency domain, thus obtaining phase values corresponding to different wavenumbers; by using least square fitting on phases and wave numbers, a group-velocity OPD was gained for the very point; and finally in terms of the relation between relative height and the group-velocity OPD, the profile of the test sample was obtained. Two tests yielded same profile result for the sample, and step heights obtained were 50.88 nm and 50.94 nm, respectively. Meantime, the sample was also measured with a Zygo Newview 7200 topography instrument, with same profile result obtained and step height differing by 0.9 nm. In addition, data processing results indicate that chromatic dispersion equal to and higher than 2nd order is negligible when applying spatial frequency domain analysis method.

  3. Time efficient 3-D electromagnetic modeling on massively parallel computers

    SciTech Connect

    Alumbaugh, D.L.; Newman, G.A.

    1995-08-01

    A numerical modeling algorithm has been developed to simulate the electromagnetic response of a three dimensional earth to a dipole source for frequencies ranging from 100 to 100MHz. The numerical problem is formulated in terms of a frequency domain--modified vector Helmholtz equation for the scattered electric fields. The resulting differential equation is approximated using a staggered finite difference grid which results in a linear system of equations for which the matrix is sparse and complex symmetric. The system of equations is solved using a preconditioned quasi-minimum-residual method. Dirichlet boundary conditions are employed at the edges of the mesh by setting the tangential electric fields equal to zero. At frequencies less than 1MHz, normal grid stretching is employed to mitigate unwanted reflections off the grid boundaries. For frequencies greater than this, absorbing boundary conditions must be employed by making the stretching parameters of the modified vector Helmholtz equation complex which introduces loss at the boundaries. To allow for faster calculation of realistic models, the original serial version of the code has been modified to run on a massively parallel architecture. This modification involves three distinct tasks; (1) mapping the finite difference stencil to a processor stencil which allows for the necessary information to be exchanged between processors that contain adjacent nodes in the model, (2) determining the most efficient method to input the model which is accomplished by dividing the input into ``global`` and ``local`` data and then reading the two sets in differently, and (3) deciding how to output the data which is an inherently nonparallel process.

  4. Multiple-Relaxation-Time Lattice Boltzmann Models in 3D

    NASA Technical Reports Server (NTRS)

    dHumieres, Dominique; Ginzburg, Irina; Krafczyk, Manfred; Lallemand, Pierre; Luo, Li-Shi; Bushnell, Dennis M. (Technical Monitor)

    2002-01-01

    This article provides a concise exposition of the multiple-relaxation-time lattice Boltzmann equation, with examples of fifteen-velocity and nineteen-velocity models in three dimensions. Simulation of a diagonally lid-driven cavity flow in three dimensions at Re=500 and 2000 is performed. The results clearly demonstrate the superior numerical stability of the multiple-relaxation-time lattice Boltzmann equation over the popular lattice Bhatnagar-Gross-Krook equation.

  5. 3D domain swapping causes extensive multimerisation of human interleukin-10 when expressed in planta.

    PubMed

    Westerhof, Lotte B; Wilbers, Ruud H P; Roosien, Jan; van de Velde, Jan; Goverse, Aska; Bakker, Jaap; Schots, Arjen

    2012-01-01

    Heterologous expression platforms of biopharmaceutical proteins have been significantly improved over the last decade. Further improvement can be established by examining the intrinsic properties of proteins. Interleukin-10 (IL-10) is an anti-inflammatory cytokine with a short half-life that plays an important role in re-establishing immune homeostasis. This homodimeric protein of 36 kDa has significant therapeutic potential to treat inflammatory and autoimmune diseases. In this study we show that the major production bottleneck of human IL-10 is not protein instability as previously suggested, but extensive multimerisation due to its intrinsic 3D domain swapping characteristic. Extensive multimerisation of human IL-10 could be visualised as granules in planta. On the other hand, mouse IL-10 hardly multimerised, which could be largely attributed to its glycosylation. By introducing a short glycine-serine-linker between the fourth and fifth alpha helix of human IL-10 a stable monomeric form of IL-10 (hIL-10(mono)) was created that no longer multimerised and increased yield up to 20-fold. However, hIL-10(mono) no longer had the ability to reduce pro-inflammatory cytokine secretion from lipopolysaccharide-stimulated macrophages. Forcing dimerisation restored biological activity. This was achieved by fusing human IL-10(mono) to the C-terminal end of constant domains 2 and 3 of human immunoglobulin A (Fcα), a natural dimer. Stable dimeric forms of IL-10, like Fcα-IL-10, may not only be a better format for improved production, but also a more suitable format for medical applications. PMID:23049703

  6. Modified block-matching 3-D filter in Laplacian pyramid domain for speckle reduction

    NASA Astrophysics Data System (ADS)

    Wen, Donghai; Jiang, Yuesong; Zhang, Yanzhong; He, Yuntao; Hua, Houqiang; Yu, Rong; Wu, Xiaofang; Gao, Qian

    2014-07-01

    The Laplacian pyramid-based block-matching 3-D filtering (BM3D) is proposed (LPBM3D) for despeckling the speckle image. For BM3D in each pyramid layer, the criterion used to collect blocks in the 3-D groups to the actual data statistics is devised. An adaptive wavelet thresholding operator that depends on both noise level and signal characteristics is proposed. The performance of the proposed LPBM3D method has been compared with the state-of-the-art methods, including the recently proposed nonlocal mean (NLM) and BM3D method. Experimental results show that the visual quality and evaluation indexes outperform the other methods with no edge preservation. The proposed algorithm effectively realizes both despeckling and edge preservation.

  7. Two-dimensional angular filter array for angular domain imaging with 3D printed angular filters

    NASA Astrophysics Data System (ADS)

    Ng, Eldon; Carson, Jeffrey J. L.

    2013-02-01

    Angular Domain Imaging (ADI) is a technique that is capable of generating two dimensional shadowgrams of attenuating targets embedded in a scattering medium. In ADI, an angular filter array (AFA) is positioned between the sample and the detector to distinguish between quasi-ballistic photons and scattered photons. An AFA is a series of micro-channels with a high aspect ratio. Previous AFAs from our group were constructed by micro-machining the micro-channels into a silicon wafer, limiting the imaging area to a one dimensional line. Two dimensional images were acquired via scanning. The objective of this work was to extend the AFA design to two dimensions to allow for two dimensional imaging with minimal scanning. The second objective of this work was to perform an initial characterization of the imaging capabilities of the 2D AFA. Our approach was to use rapid 3D prototyping techniques to generate an array of micro-channels. The imaging capabilities were then evaluated by imaging a 0.9 mm graphite rod submerged in a scattering media. Contrast was observed to improve when a second angular filter array was placed in front of the sample to mask the incoming light.

  8. 3D imaging of dental hard tissues with Fourier domain optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chen, Yueli L.; Yang, Yi; Ma, Jing; Yan, Jun; Shou, Yuanxin; Wang, Tianheng; Ramesh, Aruna; Zhao, Jing; Zhu, Quing

    2011-03-01

    A fiber optical coherence tomography (OCT) probe is used for three dimensional dental imaging. The probe has a lightweight miniaturized design with a size of a pen to facilitate clinic in vivo diagnostics. The probe is interfaced with a swept-source / Fourier domain optical coherence tomography at 20K axial scanning rate. The tooth samples were scanned from occlusal, buccal, lingual, mesial, and distal orientations. Three dimensional imaging covers tooth surface area up to 10 mm x 10 mm with a depth about 5 mm, where a majority of caries affection occurs. OCT image provides better resolution and contrast compared to gold standard dental radiography (X-ray). In particular, the technology is well suited for occlusal caries detection. This is complementary to X-ray as occlusal caries affection is difficult to be detected due to the X-ray projectile scan geometry. The 3D topology of occlusal surface as well as the dentin-enamel junction (DEJ) surface inside the tooth can be visualized. The lesion area appears with much stronger back scattering signal intensity.

  9. A novel time dependent gamma evaluation function for dynamic 2D and 3D dose distributions.

    PubMed

    Podesta, Mark; Persoon, Lucas C G G; Verhaegen, Frank

    2014-10-21

    Modern external beam radiotherapy requires detailed verification and quality assurance so that confidence can be placed on both the delivery of a single treatment fraction and on the consistency of delivery throughout the treatment course. To verify dose distributions, a comparison between prediction and measurement must be made. Comparisons between two dose distributions are commonly performed using a Gamma evaluation which is a calculation of two quantities on a pixel by pixel basis; the dose difference, and the distance to agreement. By providing acceptance criteria (e.g. 3%, 3 mm), the function will find the most appropriate match within its two degrees of freedom. For complex dynamic treatments such as IMRT or VMAT it is important to verify the dose delivery in a time dependent manner and so a gamma evaluation that includes a degree of freedom in the time domain via a third parameter, time to agreement, is presented here. A C++ (mex) based gamma function was created that could be run on either CPU and GPU computing platforms that would allow a degree of freedom in the time domain. Simple test cases were created in both 2D and 3D comprising of simple geometrical shapes with well-defined boundaries varying over time. Changes of varying magnitude in either space or time were introduced and repeated gamma analyses were performed varying the criteria. A clinical VMAT case was also included, artificial air bubbles of varying size were introduced to a patient geometry, along with shifts of varying magnitude in treatment time. For all test cases where errors in distance, dose or time were introduced, the time dependent gamma evaluation could accurately highlight the errors.The time dependent gamma function presented here allows time to be included as a degree of freedom in gamma evaluations. The function allows for 2D and 3D data sets which are varying over time to be compared using appropriate criteria without penalising minor offsets of subsequent radiation fields

  10. 3D-Pathology: a real-time system for quantitative diagnostic pathology and visualisation in 3D

    NASA Astrophysics Data System (ADS)

    Gottrup, Christian; Beckett, Mark G.; Hager, Henrik; Locht, Peter

    2005-02-01

    This paper presents the results of the 3D-Pathology project conducted under the European EC Framework 5. The aim of the project was, through the application of 3D image reconstruction and visualization techniques, to improve the diagnostic and prognostic capabilities of medical personnel when analyzing pathological specimens using transmitted light microscopy. A fully automated, computer-controlled microscope system has been developed to capture 3D images of specimen content. 3D image reconstruction algorithms have been implemented and applied to the acquired volume data in order to facilitate the subsequent 3D visualization of the specimen. Three potential application fields, immunohistology, cromogenic in situ hybridization (CISH) and cytology, have been tested using the prototype system. For both immunohistology and CISH, use of the system furnished significant additional information to the pathologist.

  11. An optical real-time 3D measurement for analysis of facial shape and movement

    NASA Astrophysics Data System (ADS)

    Zhang, Qican; Su, Xianyu; Chen, Wenjing; Cao, Yiping; Xiang, Liqun

    2003-12-01

    Optical non-contact 3-D shape measurement provides a novel and useful tool for analysis of facial shape and movement in presurgical and postsurgical regular check. In this article we present a system, which allows a precise 3-D visualization of the patient's facial before and after craniofacial surgery. We discussed, in this paper, the real time 3-D image capture, processing and the 3-D phase unwrapping method to recover complex shape deformation when the movement of the mouth. The result of real-time measurement for facial shape and movement will be helpful for the more ideal effect in plastic surgery.

  12. Time within time: 3D printed sculptures within holographic art practice

    NASA Astrophysics Data System (ADS)

    Chang, Yin-Ren; Richardson, Martin

    2015-03-01

    Holography is a time-based medium, which uses its own aesthetics and techniques to interpret colour and light. This exclusive descriptive language does not simply represent a particular scenario in the moment of recording, but also documents the performance light during the shooting process. Nowadays 3D graphic software and Internet offer practitioners greater mobility in both the development and the delivery of their artwork. Furthermore, the diverse web-based social media presents unlimited and various spaces to facilitate artists in the exchange of creative knowledge, it enables them to collaborate on their projects with external connections - audience, specialists, etc. Within the analogue holography art practice, there is a primary lack of interface, or, in other words, it cannot utilise any digital creative tools. 3D printing makes it possible to bridge the gap between cyber space and the holographic world; even more so, as this emerging technique also becomes a platform, which can connect computational data and light information. The application of 3D printing in contemporary art will reshape the process of creation, as well as the form of visual narrative itself. New technologies continually and increasingly involve the projection of another artistic dimension, and the term "visual" embarks on challenging the generally accepted notion of understanding art and interacting with it. As new pathways of practice are established, it will take years to build a complete understanding of this medium in order to be able to take a full advantage of the benefits its use offers. This paper is aimed at looking for the potential new ways of artistic expression, deriving from the interrelation between analogue holography and 3D printing. It will also attempt an articulate assessment of 3D printing within the dynamic holographic aesthetics.

  13. Real-time auto-stereoscopic visualization of 3D medical images

    NASA Astrophysics Data System (ADS)

    Portoni, Luisa; Patak, Alexandre; Noirard, Pierre; Grossetie, Jean-Claude; van Berkel, Cees

    2000-04-01

    The work here described regards multi-viewer auto- stereoscopic visualization of 3D models of anatomical structures and organs of the human body. High-quality 3D models of more than 1600 anatomical structures have been reconstructed using the Visualization Toolkit, a freely available C++ class library for 3D graphics and visualization. 2D images used for 3D reconstruction comes from the Visible Human Data Set. Auto-stereoscopic 3D image visualization is obtained using a prototype monitor developed at Philips Research Labs, UK. This special multiview 3D-LCD screen has been connected directly to a SGI workstation, where 3D reconstruction and medical imaging applications are executed. Dedicated software has been developed to implement multiview capability. A number of static or animated contemporary views of the same object can simultaneously be seen on the 3D-LCD screen by several observers, having a real 3D perception of the visualized scene without the use of extra media as dedicated glasses or head-mounted displays. Developed software applications allow real-time interaction with visualized 3D models, didactical animations and movies have been realized as well.

  14. Improved time-space method for 3-D heat transfer problems including global warming

    SciTech Connect

    Saitoh, T.S.; Wakashima, Shinichiro

    1999-07-01

    In this paper, the Time-Space Method (TSM) which has been proposed for solving general heat transfer and fluid flow problems was improved in order to cover global and urban warming. The TSM is effective in almost all-transient heat transfer and fluid flow problems, and has been already applied to the 2-D melting problems (or moving boundary problems). The computer running time will be reduced to only 1/100th--1/1000th of the existing schemes for 2-D and 3-D problems. However, in order to apply to much larger-scale problems, for example, global warming, urban warming and general ocean circulation, the SOR method (or other iterative methods) in four dimensions is somewhat tedious and provokingly slow. Motivated by the above situation, the authors improved the speed of iteration of the previous TSM by introducing the following ideas: (1) Timewise chopping: Time domain is chopped into small peaches to save memory requirement; (2) Adaptive iteration: Converged region is eliminated for further iteration; (3) Internal selective iteration: Equation with slow iteration speed in iterative procedure is selectively iterated to accelerate entire convergence; and (4) False transient integration: False transient term is added to the Poisson-type equation and the relevant solution is regarded as a parabolic equation. By adopting the above improvements, the higher-order finite different schemes and the hybrid mesh, the computer running time for the TSM is reduced to some 1/4600th of the conventional explicit method for a typical 3-D natural convection problem in a closed cavity. The proposed TSM will be more efficacious for large-scale environmental problems, such as global warming, urban warming and general ocean circulation, in which a tremendous computing time would be required.

  15. Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

    SciTech Connect

    Baudron, Anne-Marie; Riahi, Mohamed Kamel; Salomon, Julien

    2014-12-15

    In this paper we present a time-parallel algorithm for the 3D neutrons calculation of a transient model in a nuclear reactor core. The neutrons calculation consists in numerically solving the time dependent diffusion approximation equation, which is a simplified transport equation. The numerical resolution is done with finite elements method based on a tetrahedral meshing of the computational domain, representing the reactor core, and time discretization is achieved using a θ-scheme. The transient model presents moving control rods during the time of the reaction. Therefore, cross-sections (piecewise constants) are taken into account by interpolations with respect to the velocity of the control rods. The parallelism across the time is achieved by an adequate use of the parareal in time algorithm to the handled problem. This parallel method is a predictor corrector scheme that iteratively combines the use of two kinds of numerical propagators, one coarse and one fine. Our method is made efficient by means of a coarse solver defined with large time step and fixed position control rods model, while the fine propagator is assumed to be a high order numerical approximation of the full model. The parallel implementation of our method provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch–Maurer–Werner benchmark.

  16. Parareal in time 3D numerical solver for the LWR Benchmark neutron diffusion transient model

    NASA Astrophysics Data System (ADS)

    Baudron, Anne-Marie; Lautard, Jean-Jacques; Maday, Yvon; Riahi, Mohamed Kamel; Salomon, Julien

    2014-12-01

    In this paper we present a time-parallel algorithm for the 3D neutrons calculation of a transient model in a nuclear reactor core. The neutrons calculation consists in numerically solving the time dependent diffusion approximation equation, which is a simplified transport equation. The numerical resolution is done with finite elements method based on a tetrahedral meshing of the computational domain, representing the reactor core, and time discretization is achieved using a θ-scheme. The transient model presents moving control rods during the time of the reaction. Therefore, cross-sections (piecewise constants) are taken into account by interpolations with respect to the velocity of the control rods. The parallelism across the time is achieved by an adequate use of the parareal in time algorithm to the handled problem. This parallel method is a predictor corrector scheme that iteratively combines the use of two kinds of numerical propagators, one coarse and one fine. Our method is made efficient by means of a coarse solver defined with large time step and fixed position control rods model, while the fine propagator is assumed to be a high order numerical approximation of the full model. The parallel implementation of our method provides a good scalability of the algorithm. Numerical results show the efficiency of the parareal method on large light water reactor transient model corresponding to the Langenbuch-Maurer-Werner benchmark.

  17. 3D-Net: the development of a new real-time photogrammetric system

    NASA Astrophysics Data System (ADS)

    Clarke, Timothy A.; Gooch, R. M.; Ariyawansa, Dambakumbure D.; Wang, Xinchi

    1997-07-01

    There are three essential requirements for real-time 3D measurement using targeted points: fast 2D image processing; a fast solution to the correspondence problem; and fast computation of 3D coordinates. This paper brings together research work to produce such solutions and considers other work which has appeared during the project duration.

  18. Implicit scheme for Maxwell equations solution in case of flat 3D domains

    NASA Astrophysics Data System (ADS)

    Boronina, Marina; Vshivkov, Vitaly

    2016-02-01

    We present a new finite-difference scheme for Maxwell's equations solution for three-dimensional domains with different scales in different directions. The stability condition of the standard leap-frog scheme requires decreasing of the time-step with decreasing of the minimal spatial step, which depends on the minimal domain size. We overcome the conditional stability by modifying the standard scheme adding implicitness in the direction of the smallest size. The new scheme satisfies the Gauss law for the electric and magnetic fields in the final- differences. The approximation order, the maintenance of the wave amplitude and propagation speed, the invariance of the wave propagation on angle with the coordinate axes are analyzed.

  19. Holovideo: Real-time 3D range video encoding and decoding on GPU

    NASA Astrophysics Data System (ADS)

    Karpinsky, Nikolaus; Zhang, Song

    2012-02-01

    We present a 3D video-encoding technique called Holovideo that is capable of encoding high-resolution 3D videos into standard 2D videos, and then decoding the 2D videos back into 3D rapidly without significant loss of quality. Due to the nature of the algorithm, 2D video compression such as JPEG encoding with QuickTime Run Length Encoding (QTRLE) can be applied with little quality loss, resulting in an effective way to store 3D video at very small file sizes. We found that under a compression ratio of 134:1, Holovideo to OBJ file format, the 3D geometry quality drops at a negligible level. Several sets of 3D videos were captured using a structured light scanner, compressed using the Holovideo codec, and then uncompressed and displayed to demonstrate the effectiveness of the codec. With the use of OpenGL Shaders (GLSL), the 3D video codec can encode and decode in realtime. We demonstrated that for a video size of 512×512, the decoding speed is 28 frames per second (FPS) with a laptop computer using an embedded NVIDIA GeForce 9400 m graphics processing unit (GPU). Encoding can be done with this same setup at 18 FPS, making this technology suitable for applications such as interactive 3D video games and 3D video conferencing.

  20. Real-time rendering method and performance evaluation of composable 3D lenses for interactive VR.

    PubMed

    Borst, Christoph W; Tiesel, Jan-Phillip; Best, Christopher M

    2010-01-01

    We present and evaluate a new approach for real-time rendering of composable 3D lenses for polygonal scenes. Such lenses, usually called "volumetric lenses," are an extension of 2D Magic Lenses to 3D volumes in which effects are applied to scene elements. Although the composition of 2D lenses is well known, 3D composition was long considered infeasible due to both geometric and semantic complexity. Nonetheless, for a scene with multiple interactive 3D lenses, the problem of intersecting lenses must be considered. Intersecting 3D lenses in meaningful ways supports new interfaces such as hierarchical 3D windows, 3D lenses for managing and composing visualization options, or interactive shader development by direct manipulation of lenses providing component effects. Our 3D volumetric lens approach differs from other approaches and is one of the first to address efficient composition of multiple lenses. It is well-suited to head-tracked VR environments because it requires no view-dependent generation of major data structures, allowing caching and reuse of full or partial results. A Composite Shader Factory module composes shader programs for rendering composite visual styles and geometry of intersection regions. Geometry is handled by Boolean combinations of region tests in fragment shaders, which allows both convex and nonconvex CSG volumes for lens shape. Efficiency is further addressed by a Region Analyzer module and by broad-phase culling. Finally, we consider the handling of order effects for composed 3D lenses. PMID:20224135

  1. Study on basic problems in real-time 3D holographic display

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Liu, Juan; Wang, Yongtian; Pan, Yijie; Li, Xin

    2013-05-01

    In recent years, real-time three-dimensional (3D) holographic display has attracted more and more attentions. Since a holographic display can entirely reconstruct the wavefront of an actual 3D scene, it can provide all the depth cues for human eye's observation and perception, and it is believed to be the most promising technology for future 3D display. However, there are several unsolved basic problems for realizing large-size real-time 3D holographic display with a wide field of view. For examples, commercial pixelated spatial light modulators (SLM) always lead to zero-order intensity distortion; 3D holographic display needs a huge number of sampling points for the actual objects or scenes, resulting in enormous computational time; The size and the viewing zone of the reconstructed 3D optical image are limited by the space bandwidth product of the SLM; Noise from the coherent light source as well as from the system severely degrades the quality of the 3D image; and so on. Our work is focused on these basic problems, and some initial results are presented, including a technique derived theoretically and verified experimentally to eliminate the zero-order beam caused by a pixelated phase-only SLM; a method to enlarge the reconstructed 3D image and shorten the reconstruction distance using a concave reflecting mirror; and several algorithms to speed up the calculation of computer generated holograms (CGH) for the display.

  2. An iterative KP1 method for solving the transport equation in 3D domains on unstructured grids

    NASA Astrophysics Data System (ADS)

    Kokonkov, N. I.; Nikolaeva, O. V.

    2015-10-01

    A two-step iterative KP1 method for solving systems of grid equations that approximate the integro-differential transport equation in 3D domains on unstructured grids using nodal SN methods is described. Results of testing the efficiency of the proposed method in solving benchmark problems of reactor protection on tetrahedral grids are presented.

  3. Real-time 3D ultrasound imaging on a next-generation media processor

    NASA Astrophysics Data System (ADS)

    Pagoulatos, Niko; Noraz, Frederic; Kim, Yongmin

    2001-05-01

    3D ultrasound (US) provides physicians with a better understanding of human anatomy. By manipulating the 3D US data set, physicians can observe the anatomy in 3D from a number of different view directions and obtain 2D US images that would not be possible to directly acquire with the US probe. In order for 3D US to be in widespread clinical use, creation and manipulation of the 3D US data should be done at interactive times. This is a challenging task due to the large amount of data to be processed. Our group previously reported interactive 3D US imaging using a programmable mediaprocessor, Texas Instruments TMS320C80, which has been in clinical use. In this work, we present the algorithms we have developed for real-time 3D US using a newer and more powerful mediaprocessor, called MAP-CA. MAP-CA is a very long instruction word (VLIW) processor developed for multimedia applications. It has multiple execution units, a 32-kbyte data cache and a programmable DMA controller called the data streamer (DS). A forward mapping 6 DOF (for a freehand 3D US system based on magnetic position sensor for tracking the US probe) reconstruction algorithm with zero- order interpolation is achieved in 11.8 msec (84.7 frame/sec) per 512x512 8-bit US image. For 3D visualization of the reconstructed 3D US data sets, we used volume rendering and in particular the shear-warp factorization with the maximum intensity projection (MIP) rendering. 3D visualization is achieved in 53.6 msec (18.6 frames/sec) for a 128x128x128 8-bit volume and in 410.3 msec (2.4 frames/sec) for a 256x256x256 8-bit volume.

  4. 3-D segmentation of retinal blood vessels in spectral-domain OCT volumes of the optic nerve head

    NASA Astrophysics Data System (ADS)

    Lee, Kyungmoo; Abràmoff, Michael D.; Niemeijer, Meindert; Garvin, Mona K.; Sonka, Milan

    2010-03-01

    Segmentation of retinal blood vessels can provide important information for detecting and tracking retinal vascular diseases including diabetic retinopathy, arterial hypertension, arteriosclerosis and retinopathy of prematurity (ROP). Many studies on 2-D segmentation of retinal blood vessels from a variety of medical images have been performed. However, 3-D segmentation of retinal blood vessels from spectral-domain optical coherence tomography (OCT) volumes, which is capable of providing geometrically accurate vessel models, to the best of our knowledge, has not been previously studied. The purpose of this study is to develop and evaluate a method that can automatically detect 3-D retinal blood vessels from spectral-domain OCT scans centered on the optic nerve head (ONH). The proposed method utilized a fast multiscale 3-D graph search to segment retinal surfaces as well as a triangular mesh-based 3-D graph search to detect retinal blood vessels. An experiment on 30 ONH-centered OCT scans (15 right eye scans and 15 left eye scans) from 15 subjects was performed, and the mean unsigned error in 3-D of the computer segmentations compared with the independent standard obtained from a retinal specialist was 3.4 +/- 2.5 voxels (0.10 +/- 0.07 mm).

  5. Real Time 3D Facial Movement Tracking Using a Monocular Camera.

    PubMed

    Dong, Yanchao; Wang, Yanming; Yue, Jiguang; Hu, Zhencheng

    2016-01-01

    The paper proposes a robust framework for 3D facial movement tracking in real time using a monocular camera. It is designed to estimate the 3D face pose and local facial animation such as eyelid movement and mouth movement. The framework firstly utilizes the Discriminative Shape Regression method to locate the facial feature points on the 2D image and fuses the 2D data with a 3D face model using Extended Kalman Filter to yield 3D facial movement information. An alternating optimizing strategy is adopted to fit to different persons automatically. Experiments show that the proposed framework could track the 3D facial movement across various poses and illumination conditions. Given the real face scale the framework could track the eyelid with an error of 1 mm and mouth with an error of 2 mm. The tracking result is reliable for expression analysis or mental state inference. PMID:27463714

  6. LiveView3D: Real Time Data Visualization for the Aerospace Testing Environment

    NASA Technical Reports Server (NTRS)

    Schwartz, Richard J.; Fleming, Gary A.

    2006-01-01

    This paper addresses LiveView3D, a software package and associated data visualization system for use in the aerospace testing environment. The LiveView3D system allows researchers to graphically view data from numerous wind tunnel instruments in real time in an interactive virtual environment. The graphical nature of the LiveView3D display provides researchers with an intuitive view of the measurement data, making it easier to interpret the aerodynamic phenomenon under investigation. LiveView3D has been developed at the NASA Langley Research Center and has been applied in the Langley Unitary Plan Wind Tunnel (UPWT). This paper discusses the capabilities of the LiveView3D system, provides example results from its application in the UPWT, and outlines features planned for future implementation.

  7. Time- and Computation-Efficient Calibration of MEMS 3D Accelerometers and Gyroscopes

    PubMed Central

    Stančin, Sara; Tomažič, Sašo

    2014-01-01

    We propose calibration methods for microelectromechanical system (MEMS) 3D accelerometers and gyroscopes that are efficient in terms of time and computational complexity. The calibration process for both sensors is simple, does not require additional expensive equipment, and can be performed in the field before or between motion measurements. The methods rely on a small number of defined calibration measurements that are used to obtain the values of 12 calibration parameters. This process enables the static compensation of sensor inaccuracies. The values detected by the 3D sensor are interpreted using a generalized 3D sensor model. The model assumes that the values detected by the sensor are equal to the projections of the measured value on the sensor sensitivity axes. Although this finding is trivial for 3D accelerometers, its validity for 3D gyroscopes is not immediately apparent; thus, this paper elaborates on this latter topic. For an example sensor device, calibration parameters were established using calibration measurements of approximately 1.5 min in duration for the 3D accelerometer and 2.5 min in duration for the 3D gyroscope. Correction of each detected 3D value using the established calibration parameters in further measurements requires only nine addition and nine multiplication operations. PMID:25123469

  8. Multithreaded real-time 3D image processing software architecture and implementation

    NASA Astrophysics Data System (ADS)

    Ramachandra, Vikas; Atanassov, Kalin; Aleksic, Milivoje; Goma, Sergio R.

    2011-03-01

    Recently, 3D displays and videos have generated a lot of interest in the consumer electronics industry. To make 3D capture and playback popular and practical, a user friendly playback interface is desirable. Towards this end, we built a real time software 3D video player. The 3D video player displays user captured 3D videos, provides for various 3D specific image processing functions and ensures a pleasant viewing experience. Moreover, the player enables user interactivity by providing digital zoom and pan functionalities. This real time 3D player was implemented on the GPU using CUDA and OpenGL. The player provides user interactive 3D video playback. Stereo images are first read by the player from a fast drive and rectified. Further processing of the images determines the optimal convergence point in the 3D scene to reduce eye strain. The rationale for this convergence point selection takes into account scene depth and display geometry. The first step in this processing chain is identifying keypoints by detecting vertical edges within the left image. Regions surrounding reliable keypoints are then located on the right image through the use of block matching. The difference in the positions between the corresponding regions in the left and right images are then used to calculate disparity. The extrema of the disparity histogram gives the scene disparity range. The left and right images are shifted based upon the calculated range, in order to place the desired region of the 3D scene at convergence. All the above computations are performed on one CPU thread which calls CUDA functions. Image upsampling and shifting is performed in response to user zoom and pan. The player also consists of a CPU display thread, which uses OpenGL rendering (quad buffers). This also gathers user input for digital zoom and pan and sends them to the processing thread.

  9. Efficient 3D Acoustic Numerical modeling in the Logarithmic-grid using the Expanding Domain Method

    NASA Astrophysics Data System (ADS)

    Hong, B. R.; Chung, W.; Ko, H.; Bae, H. S.

    2015-12-01

    In the numerical modeling of seismic wave propagation by the use of a discrete computing domain, dispersion analysis is preceded by the determination of the spatial grid spacings in order to ensure accurate modeling results. Grid spacing is a function of wavelength, and the wavelength depends on the minimum velocity and maximum source frequency. Therefore, as the frequency increases, the number of grids increase and this leads to computational overburden. In order to reduce the computing complexity, coordinate transformation techniques such as Riemannian coordinates and logarithmic grid sets are proposed. Riemannian wave-field extrapolation is a way to reformulate the wave-field by expressing it in Riemannian coordinates. In the logarithmic grid, grid spacing changes logarithmically, so this enables us to reduce the number of grids compared to a conventional grid set. Furthermore, this could completely remove boundary reflections by extending the model dimensions. However, numerical modeling in the logarithmic grid is still inefficient because it is performed for whole model at every individual time step. In this study we applied the expanding domain method to the logarithmic modeling in order to improve computational efficiency. This method, based on amplitude comparison, excludes computations for zero wave-fields by considering a non-zero domain boundary. Numerical examples demonstrated that our new modeling method enhances computational efficiency maintaining accuracy compared with conventional modeling methods. In wider and higher-order dimensions, particularly, the efficiency of our modeling method increased. Our new modeling technique could also be applied to the generation of underwater target echo signals requiring high frequency analysis.

  10. Hinge-loop mutation can be used to control 3D domain swapping and amyloidogenesis of human cystatin C.

    PubMed

    Orlikowska, Marta; Jankowska, Elżbieta; Kołodziejczyk, Robert; Jaskólski, Mariusz; Szymańska, Aneta

    2011-02-01

    Cystatins are natural inhibitors of cysteine proteases, enzymes that are widely distributed in animals, plants, and microorganisms. Human cystatin C (hCC) has been also recognized as an aggregating protein directly involved in the formation of pathological amyloid fibrils, and these amyloidogenic properties greatly increase in a naturally occurring L68Q hCC variant. For a long time only dimeric structure of wild-type hCC has been known. The dimer is created through 3D domain swapping process, in which two parts of the cystatin structure become separated from each other and next exchanged between two molecules. Important role in the domain swapping plays the L1 loop, which connects the exchanging segments and, upon dimerization, transforms from a β-turn into a part of a long β-strand. In the very recently published first monomeric structure of human cystatin C (hCC-stab1), dimerization was abrogated due to clasping of the β-strands from the swapping domains by an engineered disulfide bridge. We have designed and constructed another mutated cystatin C with the smallest possible structural intervention, that is a single-point mutation replacing hydrophobic V57 from the L1 loop by polar asparagine, known as a stabilizer of a β-turn motif. V57N hCC mutant occurred to be stable in its monomeric form and crystallized as a monomer, revealing typical cystatin fold with a five-stranded antiparallel β-sheet wrapped around an α-helix. Here we report a 2.04 Å resolution crystal structure of V57N hCC and discuss the architecture of the protein in comparison to chicken cystatin, hCC-stab1 and dimeric hCC. PMID:21074623

  11. High-resolution, real-time simultaneous 3D surface geometry and temperature measurement.

    PubMed

    An, Yatong; Zhang, Song

    2016-06-27

    This paper presents a method to simultaneously measure three-dimensional (3D) surface geometry and temperature in real time. Specifically, we developed 1) a holistic approach to calibrate both a structured light system and a thermal camera under exactly the same world coordinate system even though these two sensors do not share the same wavelength; and 2) a computational framework to determine the sub-pixel corresponding temperature for each 3D point as well as discard those occluded points. Since the thermal 2D imaging and 3D visible imaging systems do not share the same spectrum of light, they can perform sensing simultaneously in real time: we developed a hardware system that can achieve real-time 3D geometry and temperature measurement at 26 Hz with 768 × 960 points per frame. PMID:27410608

  12. Advanced Visualization of Experimental Data in Real Time Using LiveView3D

    NASA Technical Reports Server (NTRS)

    Schwartz, Richard J.; Fleming, Gary A.

    2006-01-01

    LiveView3D is a software application that imports and displays a variety of wind tunnel derived data in an interactive virtual environment in real time. LiveView3D combines the use of streaming video fed into a three-dimensional virtual representation of the test configuration with networked communications to the test facility Data Acquisition System (DAS). This unified approach to real time data visualization provides a unique opportunity to comprehend very large sets of diverse forms of data in a real time situation, as well as in post-test analysis. This paper describes how LiveView3D has been implemented to visualize diverse forms of aerodynamic data gathered during wind tunnel experiments, most notably at the NASA Langley Research Center Unitary Plan Wind Tunnel (UPWT). Planned future developments of the LiveView3D system are also addressed.

  13. Registration of 2D cardiac images to real-time 3D ultrasound volumes for 3D stress echocardiography

    NASA Astrophysics Data System (ADS)

    Leung, K. Y. Esther; van Stralen, Marijn; Voormolen, Marco M.; van Burken, Gerard; Nemes, Attila; ten Cate, Folkert J.; Geleijnse, Marcel L.; de Jong, Nico; van der Steen, Antonius F. W.; Reiber, Johan H. C.; Bosch, Johan G.

    2006-03-01

    Three-dimensional (3D) stress echocardiography is a novel technique for diagnosing cardiac dysfunction, by comparing wall motion of the left ventricle under different stages of stress. For quantitative comparison of this motion, it is essential to register the ultrasound data. We propose an intensity based rigid registration method to retrieve two-dimensional (2D) four-chamber (4C), two-chamber, and short-axis planes from the 3D data set acquired in the stress stage, using manually selected 2D planes in the rest stage as reference. The algorithm uses the Nelder-Mead simplex optimization to find the optimal transformation of one uniform scaling, three rotation, and three translation parameters. We compared registration using the SAD, SSD, and NCC metrics, performed on four resolution levels of a Gaussian pyramid. The registration's effectiveness was assessed by comparing the 3D positions of the registered apex and mitral valve midpoints and 4C direction with the manually selected results. The registration was tested on data from 20 patients. Best results were found using the NCC metric on data downsampled with factor two: mean registration errors were 8.1mm, 5.4mm, and 8.0° in the apex position, mitral valve position, and 4C direction respectively. The errors were close to the interobserver (7.1mm, 3.8mm, 7.4°) and intraobserver variability (5.2mm, 3.3mm, 7.0°), and better than the error before registration (9.4mm, 9.0mm, 9.9°). We demonstrated that the registration algorithm visually and quantitatively improves the alignment of rest and stress data sets, performing similar to manual alignment. This will improve automated analysis in 3D stress echocardiography.

  14. Real-time 3D video compression for tele-immersive environments

    NASA Astrophysics Data System (ADS)

    Yang, Zhenyu; Cui, Yi; Anwar, Zahid; Bocchino, Robert; Kiyanclar, Nadir; Nahrstedt, Klara; Campbell, Roy H.; Yurcik, William

    2006-01-01

    Tele-immersive systems can improve productivity and aid communication by allowing distributed parties to exchange information via a shared immersive experience. The TEEVE research project at the University of Illinois at Urbana-Champaign and the University of California at Berkeley seeks to foster the development and use of tele-immersive environments by a holistic integration of existing components that capture, transmit, and render three-dimensional (3D) scenes in real time to convey a sense of immersive space. However, the transmission of 3D video poses significant challenges. First, it is bandwidth-intensive, as it requires the transmission of multiple large-volume 3D video streams. Second, existing schemes for 2D color video compression such as MPEG, JPEG, and H.263 cannot be applied directly because the 3D video data contains depth as well as color information. Our goal is to explore from a different angle of the 3D compression space with factors including complexity, compression ratio, quality, and real-time performance. To investigate these trade-offs, we present and evaluate two simple 3D compression schemes. For the first scheme, we use color reduction to compress the color information, which we then compress along with the depth information using zlib. For the second scheme, we use motion JPEG to compress the color information and run-length encoding followed by Huffman coding to compress the depth information. We apply both schemes to 3D videos captured from a real tele-immersive environment. Our experimental results show that: (1) the compressed data preserves enough information to communicate the 3D images effectively (min. PSNR > 40) and (2) even without inter-frame motion estimation, very high compression ratios (avg. > 15) are achievable at speeds sufficient to allow real-time communication (avg. ~ 13 ms per 3D video frame).

  15. PGD and separated space variables representation for linear elasticity in 3D representation of plate domains

    NASA Astrophysics Data System (ADS)

    Bognet, B.; Leygue, A.; Chinesta, F.; Poitou, A.

    2011-01-01

    In this paper, we focus on the simulation of linear elastic behaviour of plates using a 3D approach which numerical cost only scales like a 2D one. In the case of plates, the kinematic hypothesis introduced in plate theories to go from 3D to 2D is usually unsatisfactory where one cannot rely on St Venant's principle (usually close to the plate edges). We propose to apply the PGD (Proper Generalized Decomposition) method [1] to the simulation of the linear elastic behavior of plates. This method allows us to separately search for the in-plane and the out-of plane contributions to the 3D solution, yielding significant savings in computational cost. The method is validated on a simple case and its full potential is then presented for the simulation of the behavior of laminated composite plates.

  16. Real-time volume rendering of 4D image using 3D texture mapping

    NASA Astrophysics Data System (ADS)

    Hwang, Jinwoo; Kim, June-Sic; Kim, Jae Seok; Kim, In Young; Kim, Sun Il

    2001-05-01

    Four dimensional image is 3D volume data that varies with time. It is used to express deforming or moving object in virtual surgery of 4D ultrasound. It is difficult to render 4D image by conventional ray-casting or shear-warp factorization methods because of their time-consuming rendering time or pre-processing stage whenever the volume data are changed. Even 3D texture mapping is used, repeated volume loading is also time-consuming in 4D image rendering. In this study, we propose a method to reduce data loading time using coherence between currently loaded volume and previously loaded volume in order to achieve real time rendering based on 3D texture mapping. Volume data are divided into small bricks and each brick being loaded is tested for similarity to one which was already loaded in memory. If the brick passed the test, it is defined as 3D texture by OpenGL functions. Later, the texture slices of the brick are mapped into polygons and blended by OpenGL blending functions. All bricks undergo this test. Continuously deforming fifty volumes are rendered in interactive time with SGI ONYX. Real-time volume rendering based on 3D texture mapping is currently available on PC.

  17. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    PubMed Central

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-01-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the “non-progressing” and “progressing” glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection. PMID:25606299

  18. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    NASA Astrophysics Data System (ADS)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  19. 3D Markov Process for Traffic Flow Prediction in Real-Time.

    PubMed

    Ko, Eunjeong; Ahn, Jinyoung; Kim, Eun Yi

    2016-01-01

    Recently, the correct estimation of traffic flow has begun to be considered an essential component in intelligent transportation systems. In this paper, a new statistical method to predict traffic flows using time series analyses and geometric correlations is proposed. The novelty of the proposed method is two-fold: (1) a 3D heat map is designed to describe the traffic conditions between roads, which can effectively represent the correlations between spatially- and temporally-adjacent traffic states; and (2) the relationship between the adjacent roads on the spatiotemporal domain is represented by cliques in MRF and the clique parameters are obtained by example-based learning. In order to assess the validity of the proposed method, it is tested using data from expressway traffic that are provided by the Korean Expressway Corporation, and the performance of the proposed method is compared with existing approaches. The results demonstrate that the proposed method can predict traffic conditions with an accuracy of 85%, and this accuracy can be improved further. PMID:26821025

  20. 3D Markov Process for Traffic Flow Prediction in Real-Time

    PubMed Central

    Ko, Eunjeong; Ahn, Jinyoung; Kim, Eun Yi

    2016-01-01

    Recently, the correct estimation of traffic flow has begun to be considered an essential component in intelligent transportation systems. In this paper, a new statistical method to predict traffic flows using time series analyses and geometric correlations is proposed. The novelty of the proposed method is two-fold: (1) a 3D heat map is designed to describe the traffic conditions between roads, which can effectively represent the correlations between spatially- and temporally-adjacent traffic states; and (2) the relationship between the adjacent roads on the spatiotemporal domain is represented by cliques in MRF and the clique parameters are obtained by example-based learning. In order to assess the validity of the proposed method, it is tested using data from expressway traffic that are provided by the Korean Expressway Corporation, and the performance of the proposed method is compared with existing approaches. The results demonstrate that the proposed method can predict traffic conditions with an accuracy of 85%, and this accuracy can be improved further. PMID:26821025

  1. [3D real time contrast enhanced ultrasonography,a new technique].

    PubMed

    Dietrich, C F

    2002-02-01

    While 3D sonography has become established in gynecology, abdominal applications have been mainly restricted to case reports. However, recent advances in computer technology have supported the development of new systems with motion detection methods and image registration algorithms - making it possible to acquire 3D data without position sensors, before and after administration of contrast enhancing agents. Hepatic (and also splenic) applications involve the topographic localization of masses in relation to the vessels, e.g. hepatic veins and portal vein branches prior to surgical procedures (segment localization). 3D imaging in the characterization of liver tumors after administration of contrast enhancing agents could become of special importance. We report on the first use of 3D imaging of the liver and spleen under real time conditions in 10 patients, using contrast enhanced phase inversion imaging with low mechanical index, which may improve the detection rate and characterization of liver and splenic tumors. PMID:11898076

  2. Real-Time 3D Contrast-Enhanced Transcranial Ultrasound and Aberration Correction

    PubMed Central

    Ivancevich, Nikolas M.; Pinton, Gianmarco F.; Nicoletto, Heather A.; Bennett, Ellen; Laskowitz, Daniel T.; Smith, Stephen W.

    2008-01-01

    Contrast-enhanced (CE) transcranial ultrasound (US) and reconstructed 3D transcranial ultrasound have shown advantages over traditional methods in a variety of cerebrovascular diseases. We present the results from a novel ultrasound technique, namely real-time 3D contrast-enhanced transcranial ultrasound. Using real-time 3D (RT3D) ultrasound and micro-bubble contrast agent, we scanned 17 healthy volunteers via a single temporal window and 9 via the sub-occipital window and report our detection rates for the major cerebral vessels. In 71% of subjects, both of our observers identified the ipsilateral circle of Willis from the temporal window, and in 59% we imaged the entire circle of Willis. From the sub-occipital window, both observers detected the entire vertebrobasilar circulation in 22% of subjects, and in 44% the basilar artery. After performing phase aberration correction on one subject, we were able to increase the diagnostic value of the scan, detecting a vessel not present in the uncorrected scan. These preliminary results suggest that RT3D CE transcranial US and RT3D CE transcranial US with phase aberration correction have the potential to greatly impact the field of neurosonology. PMID:18395321

  3. 3D shape tracking of minimally invasive medical instruments using optical frequency domain reflectometry

    NASA Astrophysics Data System (ADS)

    Parent, Francois; Kanti Mandal, Koushik; Loranger, Sebastien; Watanabe Fernandes, Eric Hideki; Kashyap, Raman; Kadoury, Samuel

    2016-03-01

    We propose here a new alternative to provide real-time device tracking during minimally invasive interventions using a truly-distributed strain sensor based on optical frequency domain reflectometry (OFDR) in optical fibers. The guidance of minimally invasive medical instruments such as needles or catheters (ex. by adding a piezoelectric coating) has been the focus of extensive research in the past decades. Real-time tracking of instruments in medical interventions facilitates image guidance and helps the user to reach a pre-localized target more precisely. Image-guided systems using ultrasound imaging and shape sensors based on fiber Bragg gratings (FBG)-embedded optical fibers can provide retroactive feedback to the user in order to reach the targeted areas with even more precision. However, ultrasound imaging with electro-magnetic tracking cannot be used in the magnetic resonance imaging (MRI) suite, while shape sensors based on FBG embedded in optical fibers provides discrete values of the instrument position, which requires approximations to be made to evaluate its global shape. This is why a truly-distributed strain sensor based on OFDR could enhance the tracking accuracy. In both cases, since the strain is proportional to the radius of curvature of the fiber, a strain sensor can provide the three-dimensional shape of medical instruments by simply inserting fibers inside the devices. To faithfully follow the shape of the needle in the tracking frame, 3 fibers glued in a specific geometry are used, providing 3 degrees of freedom along the fiber. Near real-time tracking of medical instruments is thus obtained offering clear advantages for clinical monitoring in remotely controlled catheter or needle guidance. We present results demonstrating the promising aspects of this approach as well the limitations of using the OFDR technique.

  4. Determination and validation of mTOR kinase-domain 3D structure by homology modeling

    PubMed Central

    Lakhlili, Wiame; Chevé, Gwénaël; Yasri, Abdelaziz; Ibrahimi, Azeddine

    2015-01-01

    The AKT/mammalian target of rapamycin (mTOR) pathway is considered as one of the commonly activated and deregulated signaling pathways in human cancer. mTOR is associated with other proteins in two molecular complexes: mTOR complex 1/Raptor and the mTOR complex 2/Rictor. Using the crystal structure of the related lipid kinase PI3Kγ, we built a model of the catalytic region of mTOR. The modeling of the three-dimensional (3D) structure of the mTOR was performed by homology modeling program SWISS-MODEL. The quality and validation of the obtained model were performed using PROCHECK and PROVE softwares. The overall stereochemical property of the protein was assessed by the Ramachandran plot. The model validation was also done by docking of known inhibitors. In this paper, we describe and validate a 3D model for the mTOR catalytic site. PMID:26257525

  5. JP3D compressed-domain watermarking of volumetric medical data sets

    NASA Astrophysics Data System (ADS)

    Ouled Zaid, Azza; Makhloufi, Achraf; Olivier, Christian

    2010-01-01

    Increasing transmission of medical data across multiple user systems raises concerns for medical image watermarking. Additionaly, the use of volumetric images triggers the need for efficient compression techniques in picture archiving and communication systems (PACS), or telemedicine applications. This paper describes an hybrid data hiding/compression system, adapted to volumetric medical imaging. The central contribution is to integrate blind watermarking, based on turbo trellis-coded quantization (TCQ), to JP3D encoder. Results of our method applied to Magnetic Resonance (MR) and Computed Tomography (CT) medical images have shown that our watermarking scheme is robust to JP3D compression attacks and can provide relative high data embedding rate whereas keep a relative lower distortion.

  6. Modulated Magnetic Nanowires for Controlling Domain Wall Motion: Toward 3D Magnetic Memories.

    PubMed

    Ivanov, Yurii P; Chuvilin, Andrey; Lopatin, Sergei; Kosel, Jurgen

    2016-05-24

    Cylindrical magnetic nanowires are attractive materials for next generation data storage devices owing to the theoretically achievable high domain wall velocity and their efficient fabrication in highly dense arrays. In order to obtain control over domain wall motion, reliable and well-defined pinning sites are required. Here, we show that modulated nanowires consisting of alternating nickel and cobalt sections facilitate efficient domain wall pinning at the interfaces of those sections. By combining electron holography with micromagnetic simulations, the pinning effect can be explained by the interaction of the stray fields generated at the interface and the domain wall. Utilizing a modified differential phase contrast imaging, we visualized the pinned domain wall with a high resolution, revealing its three-dimensional vortex structure with the previously predicted Bloch point at its center. These findings suggest the potential of modulated nanowires for the development of high-density, three-dimensional data storage devices. PMID:27138460

  7. Real-time 3D surface-image-guided beam setup in radiotherapy of breast cancer

    SciTech Connect

    Djajaputra, David; Li Shidong

    2005-01-01

    We describe an approach for external beam radiotherapy of breast cancer that utilizes the three-dimensional (3D) surface information of the breast. The surface data of the breast are obtained from a 3D optical camera that is rigidly mounted on the ceiling of the treatment vault. This 3D camera utilizes light in the visible range therefore it introduces no ionization radiation to the patient. In addition to the surface topographical information of the treated area, the camera also captures gray-scale information that is overlaid on the 3D surface image. This allows us to visualize the skin markers and automatically determine the isocenter position and the beam angles in the breast tangential fields. The field sizes and shapes of the tangential, supraclavicular, and internal mammary gland fields can all be determined according to the 3D surface image of the target. A least-squares method is first introduced for the tangential-field setup that is useful for compensation of the target shape changes. The entire process of capturing the 3D surface data and subsequent calculation of beam parameters typically requires less than 1 min. Our tests on phantom experiments and patient images have achieved the accuracy of 1 mm in shift and 0.5 deg. in rotation. Importantly, the target shape and position changes in each treatment session can both be corrected through this real-time image-guided system.

  8. FPGA-based real-time anisotropic diffusion filtering of 3D ultrasound images

    NASA Astrophysics Data System (ADS)

    Castro-Pareja, Carlos R.; Dandekar, Omkar S.; Shekhar, Raj

    2005-02-01

    Three-dimensional ultrasonic imaging, especially the emerging real-time version of it, is particularly valuable in medical applications such as echocardiography, obstetrics and surgical navigation. A known problem with ultrasound images is their high level of speckle noise. Anisotropic diffusion filtering has been shown to be effective in enhancing the visual quality of 3D ultrasound images and as preprocessing prior to advanced image processing. However, due to its arithmetic complexity and the sheer size of 3D ultrasound images, it is not possible to perform online, real-time anisotropic diffusion filtering using standard software implementations. We present an FPGA-based architecture that allows performing anisotropic diffusion filtering of 3D images at acquisition rates, thus enabling the use of this filtering technique in real-time applications, such as visualization, registration and volume rendering.

  9. Time-Domain Simulation of RF Couplers

    SciTech Connect

    Smithe, David; Carlsson, Johan; Austin, Travis

    2009-11-26

    We have developed a finite-difference time-domain (FDTD) fluid-like approach to integrated plasma-and-coupler simulation [1], and show how it can be used to model LH and ICRF couplers in the MST and larger tokamaks.[2] This approach permits very accurate 3-D representation of coupler geometry, and easily includes non-axi-symmetry in vessel wall, magnetic equilibrium, and plasma density. The plasma is integrated with the FDTD Maxwell solver in an implicit solve that steps over electron time-scales, and permits tenuous plasma in the coupler itself, without any need to distinguish or interface between different regions of vacuum and/or plasma. The FDTD algorithm is also generalized to incorporate a time-domain sheath potential [3] on metal structures within the simulation, to look for situations where the sheath potential might generate local sputtering opportunities. Benchmarking of the time-domain sheath algorithm has been reported in the references. Finally, the time-domain software [4] permits the use of particles, either as field diagnostic (test particles) or to self-consistently compute plasma current from the applied RF power.

  10. High-resolution real-time 3D shape measurement on a portable device

    NASA Astrophysics Data System (ADS)

    Karpinsky, Nikolaus; Hoke, Morgan; Chen, Vincent; Zhang, Song

    2013-09-01

    Recent advances in technology have enabled the acquisition of high-resolution 3D models in real-time though the use of structured light scanning techniques. While these advances are impressive, they require large amounts of computing power, thus being limited to using large desktop computers with high end CPUs and sometimes GPUs. This is undesirable in making high-resolution real-time 3D scanners ubiquitous in our mobile lives. To address this issue, this work describes and demonstrates a real-time 3D scanning system that is realized on a mobile device, namely a laptop computer, which can achieve speeds of 20fps 3D at a resolution of 640x480 per frame. By utilizing a graphics processing unit (GPU) as a multipurpose parallel processor, along with a parallel phase shifting technique, we are able to realize the entire 3D processing pipeline in parallel. To mitigate high speed camera transfer problems, which typically require a dedicated frame grabber, we make use of USB 3.0 along with direct memory access (DMA) to transfer camera images to the GPU. To demonstrate the effectiveness of the technique, we experiment with the scanner on both static geometry of a statue and dynamic geometry of a deforming material sample in front of the system.

  11. [A new approach to the tricuspid valve in Ebstein's anomaly by real time 3D echocardiography].

    PubMed

    Taktak, A; Acar, P; Dulac, Y; Abadir, S; Chilon, T; Roux, D; Glock, Y; Fournial, G

    2005-05-01

    Ebstein's anomaly affects the tricuspid valve with a large range of anatomical forms. Successful tricuspid valvuloplasty depends mainly on the ability to mobilise the leaflets. Evaluation of the leaflet surface is difficult with 2D echocardiography whereas 3D echocardiography provides intracardiac views of the valve. The authors used this method in 10 patients with 3 modes of imaging: biplane, real time and total volume. The study population (age: 1 day to 30 years) included: 1 prenatal diagnosis, 1 neonate with refractory cyanosis, 5 patients with mild tricuspid regurgitation, 3 patients with severe tricuspid regurgitation, 2 of whom underwent valvuloplasty. 3D echocardiography was disappointing in the foetus and neonate because of poor spatial resolution. The ventricular view of the tricuspid valve in older children and adults allowed analysis of tricuspid leaflet coaptation and of the mechanism of regurgitation. The commissures and leaflet surfaces were assessed. The results of surgical valvuloplasty could be evaluated by 3D echocardiography. 3D echocardiography is now transthoracic and a real time investigation. Technical advances are required before it comes into routine usage: a more manoeuvrable matricial probe (integrating pulsed and continuous wave Doppler) and larger volume real time 3D imaging with better resolution. Its role in the assessment of Ebstein's anomaly should be evaluated in a larger series of patients. PMID:15966604

  12. Genome-Wide Prediction and Analysis of 3D-Domain Swapped Proteins in the Human Genome from Sequence Information

    PubMed Central

    Upadhyay, Atul Kumar; Sowdhamini, Ramanathan

    2016-01-01

    3D-domain swapping is one of the mechanisms of protein oligomerization and the proteins exhibiting this phenomenon have many biological functions. These proteins, which undergo domain swapping, have acquired much attention owing to their involvement in human diseases, such as conformational diseases, amyloidosis, serpinopathies, proteionopathies etc. Early realisation of proteins in the whole human genome that retain tendency to domain swap will enable many aspects of disease control management. Predictive models were developed by using machine learning approaches with an average accuracy of 78% (85.6% of sensitivity, 87.5% of specificity and an MCC value of 0.72) to predict putative domain swapping in protein sequences. These models were applied to many complete genomes with special emphasis on the human genome. Nearly 44% of the protein sequences in the human genome were predicted positive for domain swapping. Enrichment analysis was performed on the positively predicted sequences from human genome for their domain distribution, disease association and functional importance based on Gene Ontology (GO). Enrichment analysis was also performed to infer a better understanding of the functional importance of these sequences. Finally, we developed hinge region prediction, in the given putative domain swapped sequence, by using important physicochemical properties of amino acids. PMID:27467780

  13. Time-lapse 3-D seismic imaging of shallow subsurface contaminant flow.

    PubMed

    McKenna, J; Sherlock, D; Evans, B

    2001-12-01

    This paper presents a physical modelling study outlining a technique whereby buoyant contaminant flow within water-saturated unconsolidated sand was remotely monitored utilizing the time-lapse 3-D (TL3-D) seismic response. The controlled temperature and pressure conditions, along with the high level of acquisition repeatability attainable using sandbox physical models, allow the TL3-D seismic response to pore fluid movement to be distinguished from all other effects. TL3-D seismic techniques are currently being developed to monitor hydrocarbon reserves within producing reservoirs in an endeavour to improve overall recovery. However, in many ways, sandbox models under atmospheric conditions more accurately simulate the shallow subsurface than petroleum reservoirs. For this reason, perhaps the greatest application for analogue sandbox modelling is to improve our understanding of shallow groundwater and environmental flow mechanisms. Two fluid flow simulations were conducted whereby air and kerosene were injected into separate water-saturated unconsolidated sand models. In both experiments, a base 3-D seismic volume was recorded and compared with six later monitor surveys recorded while the injection program was conducted. Normal incidence amplitude and P-wave velocity information were extracted from the TL3-D seismic data to provide visualization of contaminant migration. Reflection amplitudes displayed qualitative areal distribution of fluids when a suitable impedance contrast existed between pore fluids. TL3-D seismic reflection tomography can potentially monitor the change in areal distribution of fluid contaminants over time, indicating flow patterns. However, other research and this current work have not established a quantifiable relationship between either normal reflection amplitudes and attenuation and fluid saturation. Generally, different pore fluids will have unique seismic velocities due to differences in compressibility and density. The predictable

  14. Vorticity vector-potential method for 3D viscous incompressible flows in time-dependent curvilinear coordinates

    NASA Astrophysics Data System (ADS)

    Chen, Yu; Xie, Xilin

    2016-05-01

    E and Liu [J. Comput. Phys. 138 (1997) 57-82] put forward a finite difference method for 3D viscous incompressible flows in the vorticity-vector potential formulation on non-staggered grids. In this paper, we will extend this method to the case of flows in the presence of a deformable surface. By use of two kinds of surface differential operators, the implementation of boundary conditions on a plane is generalized to a curved smooth surface with given velocity distribution, whether this be an inflow/outflow interface or a curved wall. To deal with the irregular and varying physical domain, time-dependent curvilinear coordinates are constructed and the corresponding tensor analysis is adopted in deriving the component form of the governing equations. Therefore, the equations can be discretized and solved in a regular and fixed parametric domain. Numerical results are presented for a 3D lid-driven cavity with a deforming surface and a 3D duct flow with a deforming boundary. A new way to validate numerical simulations is proposed based on an expression for the rate-of-strain tensor on a deformable surface.

  15. Mining biological information from 3D short time-series gene expression data: the OPTricluster algorithm

    PubMed Central

    2012-01-01

    Background Nowadays, it is possible to collect expression levels of a set of genes from a set of biological samples during a series of time points. Such data have three dimensions: gene-sample-time (GST). Thus they are called 3D microarray gene expression data. To take advantage of the 3D data collected, and to fully understand the biological knowledge hidden in the GST data, novel subspace clustering algorithms have to be developed to effectively address the biological problem in the corresponding space. Results We developed a subspace clustering algorithm called Order Preserving Triclustering (OPTricluster), for 3D short time-series data mining. OPTricluster is able to identify 3D clusters with coherent evolution from a given 3D dataset using a combinatorial approach on the sample dimension, and the order preserving (OP) concept on the time dimension. The fusion of the two methodologies allows one to study similarities and differences between samples in terms of their temporal expression profile. OPTricluster has been successfully applied to four case studies: immune response in mice infected by malaria (Plasmodium chabaudi), systemic acquired resistance in Arabidopsis thaliana, similarities and differences between inner and outer cotyledon in Brassica napus during seed development, and to Brassica napus whole seed development. These studies showed that OPTricluster is robust to noise and is able to detect the similarities and differences between biological samples. Conclusions Our analysis showed that OPTricluster generally outperforms other well known clustering algorithms such as the TRICLUSTER, gTRICLUSTER and K-means; it is robust to noise and can effectively mine the biological knowledge hidden in the 3D short time-series gene expression data. PMID:22475802

  16. Spectral mapping of 3D multi-cellular tumor spheroids: time-resolved confocal microscopy.

    PubMed

    Mohapatra, Saswat; Nandi, Somen; Chowdhury, Rajdeep; Das, Gaurav; Ghosh, Surajit; Bhattacharyya, Kankan

    2016-07-21

    A tumor-like multi-cellular spheroid (3D) differs from a 2D cell in a number of ways. This is demonstrated using time resolved confocal microscopy. Two different tumor spheroids - HeLa (cervical cancer) and A549 (lung cancer) - are studied using 3 different fluorescent dyes - C153 (non-covalent), CPM (covalent) and doxorubicin (non-covalent, anti-cancer drug). The pattern of localization of these three fluorescent probes in the 3D tumor cell exhibits significant differences from that in the conventional 2D cells. For both the cells (HeLa and A549), the total uptake of doxorubicin in the 3D cell is much lower than that in the 2D cell. The uptake of doxorubicin molecules in the A549 spheroid is significantly different compared to the HeLa spheroid. The local polarity (i.e. emission maxima) and solvation dynamics in the 3D tumor cell differ from those in 2D cells. The covalent probe CPM exhibits intermittent fluorescence oscillations in the 1-2 s time scale. This is attributed to redox processes. These results may provide new insights into 3D tumors. PMID:27336201

  17. On domain decomposition preconditioner of BPS type for finite element discretizations of 3D elliptic equations

    NASA Astrophysics Data System (ADS)

    Korneev, V. G.

    2012-09-01

    BPS is a well known an efficient and rather general domain decomposition Dirichlet-Dirichlet type preconditioner, suggested in the famous series of papers Bramble, Pasciak and Schatz (1986-1989). Since then, it has been serving as the origin for the whole family of domain decomposition Dirichlet-Dirichlet type preconditioners-solvers as for h so hp discretizations of elliptic problems. For its original version, designed for h discretizations, the named authors proved the bound O(1 + log2 H/ h) for the relative condition number under some restricting conditions on the domain decomposition and finite element discretization. Here H/ h is the maximal relation of the characteristic size H of a decomposition subdomain to the mesh parameter h of its discretization. It was assumed that subdomains are images of the reference unite cube by trilinear mappings. Later similar bounds related to h discretizations were proved for more general domain decompositions, defined by means of coarse tetrahedral meshes. These results, accompanied by the development of some special tools of analysis aimed at such type of decompositions, were summarized in the book of Toselli and Widlund (2005). This paper is also confined to h discretizations. We further expand the range of admissible domain decompositions for constructing BPS preconditioners, in which decomposition subdomains can be convex polyhedrons, satisfying some conditions of shape regularity. We prove the bound for the relative condition number with the same dependence on H/ h as in the bound given above. Along the way to this result, we simplify the proof of the so called abstract bound for the relative condition number of the domain decomposition preconditioner. In the part, related to the analysis of the interface sub-problem preconditioning, our technical tools are generalization of those used by Bramble, Pasciak and Schatz.

  18. Real-time 3D-surface-guided head refixation useful for fractionated stereotactic radiotherapy

    SciTech Connect

    Li Shidong; Liu Dezhi; Yin Gongjie; Zhuang Ping; Geng, Jason

    2006-02-15

    Accurate and precise head refixation in fractionated stereotactic radiotherapy has been achieved through alignment of real-time 3D-surface images with a reference surface image. The reference surface image is either a 3D optical surface image taken at simulation with the desired treatment position, or a CT/MRI-surface rendering in the treatment plan with corrections for patient motion during CT/MRI scans and partial volume effects. The real-time 3D surface images are rapidly captured by using a 3D video camera mounted on the ceiling of the treatment vault. Any facial expression such as mouth opening that affects surface shape and location can be avoided using a new facial monitoring technique. The image artifacts on the real-time surface can generally be removed by setting a threshold of jumps at the neighboring points while preserving detailed features of the surface of interest. Such a real-time surface image, registered in the treatment machine coordinate system, provides a reliable representation of the patient head position during the treatment. A fast automatic alignment between the real-time surface and the reference surface using a modified iterative-closest-point method leads to an efficient and robust surface-guided target refixation. Experimental and clinical results demonstrate the excellent efficacy of <2 min set-up time, the desired accuracy and precision of <1 mm in isocenter shifts, and <1 deg. in rotation.

  19. IP4DI: A software for time-lapse 2D/3D DC-resistivity and induced polarization tomography

    NASA Astrophysics Data System (ADS)

    Karaoulis, M.; Revil, A.; Tsourlos, P.; Werkema, D. D.; Minsley, B. J.

    2013-04-01

    We propose a 2D/3D forward modelling and inversion package to invert direct current (DC)-resistivity, time-domain induced polarization (TDIP), and frequency-domain induced polarization (FDIP) data. Each cell used for the discretization of the 2D/3D problems is characterized by a DC-resistivity value and a chargeability or complex conductivity for TDIP/FDIP problems, respectively. The governing elliptic partial differential equations are solved with the finite element method, which can be applied for both real and complex numbers. The inversion can be performed either for a single snapshot of data or for a sequence of snapshots in order to monitor a dynamic process such as a salt tracer test. For the time-lapse inversion, we have developed an active time constrained (ATC) approach that is very efficient in filtering out noise in the data that is not correlated over time. The forward algorithm is benchmarked with simple analytical solutions. The inversion package IP4DI is benchmarked with three tests, two including simple geometries. The last one corresponds to a time-lapse resistivity problem for cross-well tomography during enhanced oil recovery. The algorithms are based on MATLAB® code package and a graphical user interface (GUI).

  20. A volumetric sensor for real-time 3D mapping and robot navigation

    NASA Astrophysics Data System (ADS)

    Fournier, Jonathan; Ricard, Benoit; Laurendeau, Denis

    2006-05-01

    The use of robots for (semi-) autonomous operations in complex terrains such as urban environments poses difficult mobility, mapping, and perception challenges. To be able to work efficiently, a robot should be provided with sensors and software such that it can perceive and analyze the world in 3D. Real-time 3D sensing and perception in this operational context are paramount. To address these challenges, DRDC Valcartier has developed over the past years a compact sensor that combines a wide baseline stereo camera and a laser scanner with a full 360 degree azimuth and 55 degree elevation field of view allowing the robot to view and manage overhang obstacles as well as obstacles at ground level. Sensing in 3D is common but to efficiently navigate and work in complex terrain, the robot should also perceive, decide and act in three dimensions. Therefore, 3D information should be preserved and exploited in all steps of the process. To achieve this, we use a multiresolution octree to store the acquired data, allowing mapping of large environments while keeping the representation compact and memory efficient. Ray tracing is used to build and update the 3D occupancy model. This model is used, via a temporary 2.5D map, for navigation, obstacle avoidance and efficient frontier-based exploration. This paper describes the volumetric sensor concept, describes its design features and presents an overview of the 3D software framework that allows 3D information persistency through all computation steps. Simulation and real-world experiments are presented at the end of the paper to demonstrate the key elements of our approach.

  1. Diagnostic value of 3D time-of-flight MRA in trigeminal neuralgia.

    PubMed

    Cai, Jing; Xin, Zhen-Xue; Zhang, Yu-Qiang; Sun, Jie; Lu, Ji-Liang; Xie, Feng

    2015-08-01

    The aim of this meta-analysis was to evaluate the diagnostic value of 3D time-of-flight magnetic resonance angiography (3D-TOF-MRA) in trigeminal neuralgia (TN). Relevant studies were identified by computerized database searches supplemented by manual search strategies. The studies were included in accordance with stringent inclusion and exclusion criteria. Following a multistep screening process, high quality studies related to the diagnostic value of 3D-TOF-MRA in TN were selected for meta-analysis. Statistical analyses were conducted using Statistical Analysis Software (version 8.2; SAS Institute, Cary, NC, USA) and Meta Disc (version 1.4; Unit of Clinical Biostatistics, Ramon y Cajal Hospital, Madrid, Spain). For the present meta-analysis, we initially retrieved 95 studies from database searches. A total of 13 studies were eventually enrolled containing a combined total of 1084 TN patients. The meta-analysis results demonstrated that the sensitivity and specificity of the diagnostic value of 3D-TOF-MRA in TN were 95% (95% confidence interval [CI] 0.93-0.96) and 77% (95% CI 0.66-0.86), respectively. The pooled positive likelihood ratio and negative likelihood ratio were 2.72 (95% CI 1.81-4.09) and 0.08 (95% CI 0.06-0.12), respectively. The pooled diagnostic odds ratio of 3D-TOF-MRA in TN was 52.92 (95% CI 26.39-106.11), and the corresponding area under the curve in the summary receiver operating characteristic curve based on the 3D-TOF-MRA diagnostic image of observers was 0.9695 (standard error 0.0165). Our results suggest that 3D-TOF-MRA has excellent sensitivity and specificity as a diagnostic tool for TN, and that it can accurately identify neurovascular compression in TN patients. PMID:26077938

  2. 3-D frequency-domain seismic wave modelling in heterogeneous, anisotropic media using a Gaussian Quadrature Grid (GQG) approach

    NASA Astrophysics Data System (ADS)

    Greenhalgh, Stewart; Zhou, Bing; Maurer, Hansruedi

    2010-05-01

    -system solver of a large dimensional, sparse and symmetric complex matrix. The compressed half-row storage scheme is the one requiring the least computer memory, but with such an optimal storage scheme, the sequential, iterative Krylov solvers are still expensive in computer time due to their slow convergence. Therefore it is crucial to improve the computational efficiency of the GQG approach by developing a parallelised, iterative preconditioned Krylov solver in the future. The GQG approach can be readily employed as the forward modelling component to yield synthetic spectral data in generalised diffraction tomography and in frequency-domain full waveform inversion. It can also be used with the adjoint method to compute the waveform sensitivity kernels for specified configurations of source-receiver pairs in arbitrary 3D anisotropic media. The accuracy and capabilities of the GQG modelling method are illustrated here by presenting all independent components of the Green's function vectors from directional sources in both homogeneous and heterogeneous, anisotropic media.

  3. Contribution of Topological Domains and Loop Formation to 3D Chromatin Organization

    PubMed Central

    Ea, Vuthy; Baudement, Marie-Odile; Lesne, Annick; Forné, Thierry

    2015-01-01

    Recent investigations on 3D chromatin folding revealed that the eukaryote genomes are both highly compartmentalized and extremely dynamic. This review presents the most recent advances in topological domains’ organization of the eukaryote genomes and discusses the relationship to chromatin loop formation. CTCF protein appears as a central factor of these two organization levels having either a strong insulating role at TAD borders, or a weaker architectural role in chromatin loop formation. TAD borders directly impact on chromatin dynamics by restricting contacts within specific genomic portions thus confining chromatin loop formation within TADs. We discuss how sub-TAD chromatin dynamics, constrained into a recently described statistical helix conformation, can produce functional interactions by contact stabilization. PMID:26226004

  4. Restoration of 3D medical images with total variation scheme on wavelet domains (TVW)

    NASA Astrophysics Data System (ADS)

    Ogier, Arnaud; Hellier, Pierre; Barillot, Christian

    2006-03-01

    The multiplicity of sensors used in medical imaging leads to different noises. Non informative noise can damage the image interpretation process and the performance of automatic analysis. The method proposed in this paper allows compensating highly noisy image data from non informative noise without sophisticated modeling of the noise statistics. This generic approach uses jointly a wavelet decomposition scheme and a non-isotropic Total Variation filtering of the transform coefficients. This framework benefits from both the hierarchical capabilities of the wavelet transform and the well-posed regularization scheme of the Total Variation. This algorithm has been tested and validated on test-bed data, as well as different clinical MR and 3D ultrasound images, enhancing the capabilities of the proposed method to cope with different noise models.

  5. Time-to-digital converter based on analog time expansion for 3D time-of-flight cameras

    NASA Astrophysics Data System (ADS)

    Tanveer, Muhammad; Nissinen, Ilkka; Nissinen, Jan; Kostamovaara, Juha; Borg, Johan; Johansson, Jonny

    2014-03-01

    This paper presents an architecture and achievable performance for a time-to-digital converter, for 3D time-of-flight cameras. This design is partitioned in two levels. In the first level, an analog time expansion, where the time interval to be measured is stretched by a factor k, is achieved by charging a capacitor with current I, followed by discharging the capacitor with a current I/k. In the second level, the final time to digital conversion is performed by a global gated ring oscillator based time-to-digital converter. The performance can be increased by exploiting its properties of intrinsic scrambling of quantization noise and mismatch error, and first order noise shaping. The stretched time interval is measured by counting full clock cycles and storing the states of nine phases of the gated ring oscillator. The frequency of the gated ring oscillator is approximately 131 MHz, and an appropriate stretch factor k, can give a resolution of ≍ 57 ps. The combined low nonlinearity of the time stretcher and the gated ring oscillator-based time-to-digital converter can achieve a distance resolution of a few centimeters with low power consumption and small area occupation. The carefully optimized circuit configuration achieved by using an edge aligner, the time amplification property and the gated ring oscillator-based time-to-digital converter may lead to a compact, low power single photon configuration for 3D time-of-flight cameras, aimed for a measurement range of 10 meters.

  6. Real-time multispectral 3-D photoacoustic imaging of blood phantoms

    NASA Astrophysics Data System (ADS)

    Kosik, Ivan; Carson, Jeffrey J. L.

    2013-03-01

    Photoacoustic imaging is exquisitely sensitive to blood and can infer blood oxygenation based on multispectral images. In this work we present multispectral real-time 3D photoacoustic imaging of blood phantoms. We used a custom-built 128-channel hemispherical transducer array coupled to two Nd:YAG pumped OPO laser systems synchronized to provide double pulse excitation at 680 nm and 1064 nm wavelengths, all during a triggered series of ultrasound pressure measurements lasting less than 300 μs. The results demonstrated that 3D PAI is capable of differentiating between oxygenated and deoxygenated blood at high speed at mm-level resolution.

  7. IMPROVEMENTS TO THE TIME STEPPING ALGORITHM OF RELAP5-3D

    SciTech Connect

    Cumberland, R.; Mesina, G.

    2009-01-01

    The RELAP5-3D time step method is used to perform thermo-hydraulic and neutronic simulations of nuclear reactors and other devices. It discretizes time and space by numerically solving several differential equations. Previously, time step size was controlled by halving or doubling the size of a previous time step. This process caused the code to run slower than it potentially could. In this research project, the RELAP5-3D time step method was modifi ed to allow a new method of changing time steps to improve execution speed and to control error. The new RELAP5-3D time step method being studied involves making the time step proportional to the material courant limit (MCL), while insuring that the time step does not increase by more than a factor of two between advancements. As before, if a step fails or mass error is excessive, the time step is cut in half. To examine performance of the new method, a measure of run time and a measure of error were plotted against a changing MCL proportionality constant (m) in seven test cases. The removal of the upper time step limit produced a small increase in error, but a large decrease in execution time. The best value of m was found to be 0.9. The new algorithm is capable of producing a signifi cant increase in execution speed, with a relatively small increase in mass error. The improvements made are now under consideration for inclusion as a special option in the RELAP5-3D production code.

  8. High speed 3D endoscopic optical frequency domain imaging probe for lung cancer diagnosis

    NASA Astrophysics Data System (ADS)

    Li, Jianan; Feroldi, Fabio; Mo, Jianhua; Helderman, Frank; de Groot, Mattijs; de Boer, Johannes F.

    2013-06-01

    We present a miniature motorized endoscopic probe for Optical Frequency Domain Imaging with an outer diameter of 1.65 mm and a rotation speed of 3,000 - 12,500 rpm. The probe has a motorized distal end which provides a significant advantage over proximally driven probes since it does not require a drive shaft to transfer the rotational torque to the distal end of the probe and functions without a fiber rotary junction. The probe has a focal Full Width at Half Maximum of 9.6 μm and a working distance of 0.47 mm. We analyzed the non-uniform rotation distortion and found a location fluctuation of only 1.87° in repeated measurements of the same object. The probe was integrated in a high-speed Optical Frequency Domain Imaging setup at 1310 nm. We demonstrated its performance with imaging ex vivo pig bronchial and in vivo goat lung.

  9. Time domain cyclostationarity signal-processing tools

    NASA Astrophysics Data System (ADS)

    Léonard, François

    2015-10-01

    This paper proposes four different time-domain tools to estimate first-order time cyclostationary signals without the need of a keyphasor signal. Applied to gearbox signals, these tacho-less methods appear intuitively simple, offer user-friendly graphic interfaces to visualize a pattern and allow the retrieval and removal of the selected cyclostationarity components in order to process higher-order spectra. Two of these tools can deal with time-varying operating conditions since they use an adaptive resampled signal driven by the vibration signal itself for order tracking. Three coherency indicators are proposed, one for every sample of the time pattern, one for each impact (tooth shock) observed in the gear mesh pattern, and one for the whole pattern. These indicators are used to detect a cyclostationarity and analyze the pattern repeatability. A gear mesh graph is also proposed to illustrate the cyclostationarity in 3D.

  10. Quantitative analysis of two-phase 3D+time aortic MR images

    NASA Astrophysics Data System (ADS)

    Zhao, Fei; Zhang, Honghai; Walker, Nicholas E.; Yang, Fuxing; Olszewski, Mark E.; Wahle, Andreas; Scholz, Thomas; Sonka, Milan

    2006-03-01

    Automated and accurate segmentation of the aorta in 3D+time MR image data is important for early detection of connective tissue disorders leading to aortic aneurysms and dissections. A computer-aided diagnosis method is reported that allows the objective identification of subjects with connective tissue disorders from two-phase 3D+time aortic MR images. Our automated segmentation method combines level-set and optimal border detection. The resulting aortic lumen surface was registered with an aortic model followed by calculation of modal indices of aortic shape and motion. The modal indices reflect the differences of any individual aortic shape and motion from an average aortic behavior. The indices were input to a Support Vector Machine (SVM) classifier and a discrimination model was constructed. 3D+time MR image data sets acquired from 22 normal and connective tissue disorder subjects at end-diastole (R-wave peak) and at 45% of the R-R interval were used to evaluate the performance of our method. The automated 3D segmentation result produced accurate aortic surfaces covering the aorta from the left-ventricular outflow tract to the diaphragm and yielded subvoxel accuracy with signed surface positioning errors of -0.09+/-1.21 voxel (-0.15+/-2.11 mm). The computer aided diagnosis method distinguished between normal and connective tissue disorder subjects with a classification correctness of 90.1 %.

  11. 3D Data Mapping and Real-Time Experiment Control and Visualization in Brain Slices.

    PubMed

    Navarro, Marco A; Hibbard, Jaime V K; Miller, Michael E; Nivin, Tyler W; Milescu, Lorin S

    2015-10-20

    Here, we propose two basic concepts that can streamline electrophysiology and imaging experiments in brain slices and enhance data collection and analysis. The first idea is to interface the experiment with a software environment that provides a 3D scene viewer in which the experimental rig, the brain slice, and the recorded data are represented to scale. Within the 3D scene viewer, the user can visualize a live image of the sample and 3D renderings of the recording electrodes with real-time position feedback. Furthermore, the user can control the instruments and visualize their status in real time. The second idea is to integrate multiple types of experimental data into a spatial and temporal map of the brain slice. These data may include low-magnification maps of the entire brain slice, for spatial context, or any other type of high-resolution structural and functional image, together with time-resolved electrical and optical signals. The entire data collection can be visualized within the 3D scene viewer. These concepts can be applied to any other type of experiment in which high-resolution data are recorded within a larger sample at different spatial and temporal coordinates. PMID:26488641

  12. A numerical method for solving the 3D unsteady incompressible Navier Stokes equations in curvilinear domains with complex immersed boundaries

    NASA Astrophysics Data System (ADS)

    Ge, Liang; Sotiropoulos, Fotis

    2007-08-01

    A novel numerical method is developed that integrates boundary-conforming grids with a sharp interface, immersed boundary methodology. The method is intended for simulating internal flows containing complex, moving immersed boundaries such as those encountered in several cardiovascular applications. The background domain (e.g. the empty aorta) is discretized efficiently with a curvilinear boundary-fitted mesh while the complex moving immersed boundary (say a prosthetic heart valve) is treated with the sharp-interface, hybrid Cartesian/immersed-boundary approach of Gilmanov and Sotiropoulos [A. Gilmanov, F. Sotiropoulos, A hybrid cartesian/immersed boundary method for simulating flows with 3d, geometrically complex, moving bodies, Journal of Computational Physics 207 (2005) 457-492.]. To facilitate the implementation of this novel modeling paradigm in complex flow simulations, an accurate and efficient numerical method is developed for solving the unsteady, incompressible Navier-Stokes equations in generalized curvilinear coordinates. The method employs a novel, fully-curvilinear staggered grid discretization approach, which does not require either the explicit evaluation of the Christoffel symbols or the discretization of all three momentum equations at cell interfaces as done in previous formulations. The equations are integrated in time using an efficient, second-order accurate fractional step methodology coupled with a Jacobian-free, Newton-Krylov solver for the momentum equations and a GMRES solver enhanced with multigrid as preconditioner for the Poisson equation. Several numerical experiments are carried out on fine computational meshes to demonstrate the accuracy and efficiency of the proposed method for standard benchmark problems as well as for unsteady, pulsatile flow through a curved, pipe bend. To demonstrate the ability of the method to simulate flows with complex, moving immersed boundaries we apply it to calculate pulsatile, physiological flow

  13. Feasibility of modulation-encoded TOBE CMUTS for real-time 3-D imaging.

    PubMed

    Chee, Ryan K W; Zemp, Roger J

    2015-04-01

    Modulation-encoded top orthogonal to bottom electrode (TOBE) capacitive micromachined ultrasound transducers (CMUTs) are proposed 2-D ultrasound transducer arrays that could allow 3-D images to be acquired in a single acquisition using only N channels for an N × N array. In the proposed modulation-encoding scheme, columns are not only biased, but also modulated with a different frequency for each column. The modulation frequencies are higher than the passband of the CMUT membranes and mix nonlinearly in CMUT cells with acoustic signals to produce acoustic signal sidebands around the modulation carriers in the frequency domain. Thus, signals from elements along a row may be read out simultaneously via frequency-domain multiplexing. We present the theory and feasibility data behind modulation-encoded TOBE CMUTs. We also present experiments showing necessary modifications to the current TOBE design that would allow for crosstalk-mitigated modulation-encoding. PMID:25881354

  14. Massive parallelization of a 3D finite difference electromagnetic forward solution using domain decomposition methods on multiple CUDA enabled GPUs

    NASA Astrophysics Data System (ADS)

    Schultz, A.

    2010-12-01

    3D forward solvers lie at the core of inverse formulations used to image the variation of electrical conductivity within the Earth's interior. This property is associated with variations in temperature, composition, phase, presence of volatiles, and in specific settings, the presence of groundwater, geothermal resources, oil/gas or minerals. The high cost of 3D solutions has been a stumbling block to wider adoption of 3D methods. Parallel algorithms for modeling frequency domain 3D EM problems have not achieved wide scale adoption, with emphasis on fairly coarse grained parallelism using MPI and similar approaches. The communications bandwidth as well as the latency required to send and receive network communication packets is a limiting factor in implementing fine grained parallel strategies, inhibiting wide adoption of these algorithms. Leading Graphics Processor Unit (GPU) companies now produce GPUs with hundreds of GPU processor cores per die. The footprint, in silicon, of the GPU's restricted instruction set is much smaller than the general purpose instruction set required of a CPU. Consequently, the density of processor cores on a GPU can be much greater than on a CPU. GPUs also have local memory, registers and high speed communication with host CPUs, usually through PCIe type interconnects. The extremely low cost and high computational power of GPUs provides the EM geophysics community with an opportunity to achieve fine grained (i.e. massive) parallelization of codes on low cost hardware. The current generation of GPUs (e.g. NVidia Fermi) provides 3 billion transistors per chip die, with nearly 500 processor cores and up to 6 GB of fast (DDR5) GPU memory. This latest generation of GPU supports fast hardware double precision (64 bit) floating point operations of the type required for frequency domain EM forward solutions. Each Fermi GPU board can sustain nearly 1 TFLOP in double precision, and multiple boards can be installed in the host computer system. We

  15. Time domain reflectometry in time variant plasmas

    NASA Technical Reports Server (NTRS)

    Scherner, Michael J.

    1992-01-01

    The effects of time-dependent electron density fluctuations on a synthesized time domain reflectometry response of a one-dimensional cold plasma sheath are considered. Numerical solutions of the Helmholtz wave equation, which describes the electric field of a normally incident plane wave in a specified static electron density profile, are used. A study of the effects of Doppler shifts resulting from moving density fluctuations in the electron density profile of the sheath is included. Varying electron density levels corrupt time domain and distance measurements. Reducing or modulating the electron density levels of a given electron density profile affects the time domain response of a plasma and results in motion of the turning point, and the effective motion has a significant effect on measuring electron density locations.

  16. Note: Time-gated 3D single quantum dot tracking with simultaneous spinning disk imaging

    NASA Astrophysics Data System (ADS)

    DeVore, M. S.; Stich, D. G.; Keller, A. M.; Cleyrat, C.; Phipps, M. E.; Hollingsworth, J. A.; Lidke, D. S.; Wilson, B. S.; Goodwin, P. M.; Werner, J. H.

    2015-12-01

    We describe recent upgrades to a 3D tracking microscope to include simultaneous Nipkow spinning disk imaging and time-gated single-particle tracking (SPT). Simultaneous 3D molecular tracking and spinning disk imaging enable the visualization of cellular structures and proteins around a given fluorescently labeled target molecule. The addition of photon time-gating to the SPT hardware improves signal to noise by discriminating against Raman scattering and short-lived fluorescence. In contrast to camera-based SPT, single-photon arrival times are recorded, enabling time-resolved spectroscopy (e.g., measurement of fluorescence lifetimes and photon correlations) to be performed during single molecule/particle tracking experiments.

  17. Note: Time-gated 3D single quantum dot tracking with simultaneous spinning disk imaging

    SciTech Connect

    DeVore, M. S.; Stich, D. G.; Keller, A. M.; Phipps, M. E.; Hollingsworth, J. A.; Goodwin, P. M.; Werner, J. H.; Cleyrat, C.; Lidke, D. S.; Wilson, B. S.

    2015-12-15

    We describe recent upgrades to a 3D tracking microscope to include simultaneous Nipkow spinning disk imaging and time-gated single-particle tracking (SPT). Simultaneous 3D molecular tracking and spinning disk imaging enable the visualization of cellular structures and proteins around a given fluorescently labeled target molecule. The addition of photon time-gating to the SPT hardware improves signal to noise by discriminating against Raman scattering and short-lived fluorescence. In contrast to camera-based SPT, single-photon arrival times are recorded, enabling time-resolved spectroscopy (e.g., measurement of fluorescence lifetimes and photon correlations) to be performed during single molecule/particle tracking experiments.

  18. Integrated endoscope for real-time 3D ultrasound imaging and hyperthermia: feasibility study.

    PubMed

    Pua, Eric C; Qiu, Yupeng; Smith, S W

    2007-01-01

    The goal of this research is to determine the feasibility of using a single endoscopic probe for the combined purpose of real-time 3D (RT3D) ultrasound imaging of a target organ and the delivery of ultrasound therapy to facilitate the absorption of compounds for cancer treatment. Recent research in ultrasound therapy has shown that ultrasound-mediated drug delivery improves absorption of treatments for prostate, cervical and esophageal cancer. The ability to combine ultrasound hyperthermia and 3D imaging could improve visualization and targeting of cancerous tissues. In this study, numerical modeling and experimental measurements were developed to determine the feasibility of combined therapy and imaging with a 1 cm diameter endoscopic RT3D probe with 504 transmitters and 252 receive channels. This device operates at 5 MHz and has a 6.3 mm x 6.3 mm aperture to produce real time 3D pyramidal scans of 60-120 degrees incorporating 64 x 64 = 4096 image lines at 30 volumes/sec interleaved with a 3D steerable therapy beam. A finite-element mesh was constructed with over 128,000 elements in LS-DYNA to simulate the induced temperature rise from our transducer with a 3 cm deep focus in tissue. Quarter-symmetry of the transducer was used to reduce mesh size and computation time. Based on intensity values calculated in Field II using the transducer's array geometry, a minimum I(SPTA) of 3.6 W/cm2 is required from our endoscope probe in order to induce a temperature rise of 4 degrees C within five minutes. Experimental measurements of the array's power output capabilities were conducted using a PVDF hydrophone placed 3 cm away from the face of the transducer in a watertank. Using a PDA14 Signatec data acquisition board to capture full volumes of transmitted ultrasound data, it was determined that the probe can presently maintain intensity values up to 2.4 W/cm2 over indefinite times for therapeutic applications combined with intermittent 3D scanning to maintain targeting

  19. High speed miniature motorized endoscopic probe for 3D optical frequency domain imaging

    NASA Astrophysics Data System (ADS)

    Li, Jianan; Feroldi, Fabio; Mo, Jianhua; Helderman, Frank; de Groot, Mattijs; de Boer, Johannes F.

    2013-03-01

    We present a miniature motorized endoscopic probe for Optical Frequency Domain Imaging with an outer diameter of 1.65 mm and a rotation speed of 3,000 - 12,500 rpm. This is the smallest motorized high speed OCT probe to our knowledge. The probe has a motorized distal end which provides a significant advantage over proximally driven probes since it does not require a drive shaft to transfer the rotational torque to the distal end of the probe and functions without a fiber rotary junction. The probe has a focal Full Width at Half Maximum of 9.6 μm and a working distance of 0.47 mm. We analyzed the non-uniform rotation distortion and found a location fluctuation of only 1.87° in repeated measurements of the same object. The probe was integrated in a high-speed Optical Frequency Domain Imaging setup at 1310 nm We demonstrated its performance with imaging ex vivo pig bronchial and in vivo goat lung.

  20. Ultra-Wideband Time-Difference-of-Arrival High Resolution 3D Proximity Tracking System

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Phan, Chau; Dekome, Kent; Dusl, John

    2010-01-01

    This paper describes a research and development effort for a prototype ultra-wideband (UWB) tracking system that is currently under development at NASA Johnson Space Center (JSC). The system is being studied for use in tracking of lunar./Mars rovers and astronauts during early exploration missions when satellite navigation systems are not available. U IATB impulse radio (UWB-IR) technology is exploited in the design and implementation of the prototype location and tracking system. A three-dimensional (3D) proximity tracking prototype design using commercially available UWB products is proposed to implement the Time-Difference- Of-Arrival (TDOA) tracking methodology in this research effort. The TDOA tracking algorithm is utilized for location estimation in the prototype system, not only to exploit the precise time resolution possible with UWB signals, but also to eliminate the need for synchronization between the transmitter and the receiver. Simulations show that the TDOA algorithm can achieve the fine tracking resolution with low noise TDOA estimates for close-in tracking. Field tests demonstrated that this prototype UWB TDOA High Resolution 3D Proximity Tracking System is feasible for providing positioning-awareness information in a 3D space to a robotic control system. This 3D tracking system is developed for a robotic control system in a facility called "Moonyard" at Honeywell Defense & System in Arizona under a Space Act Agreement.

  1. Real-Time 3d Reconstruction from Images Taken from AN Uav

    NASA Astrophysics Data System (ADS)

    Zingoni, A.; Diani, M.; Corsini, G.; Masini, A.

    2015-08-01

    We designed a method for creating 3D models of objects and areas from two aerial images acquired from an UAV. The models are generated automatically and in real-time, and consist in dense and true-colour reconstructions of the considered areas, which give the impression to the operator to be physically present within the scene. The proposed method only needs a cheap compact camera, mounted on a small UAV. No additional instrumentation is necessary, so that the costs are very limited. The method consists of two main parts: the design of the acquisition system and the 3D reconstruction algorithm. In the first part, the choices for the acquisition geometry and for the camera parameters are optimized, in order to yield the best performance. In the second part, a reconstruction algorithm extracts the 3D model from the two acquired images, maximizing the accuracy under the real-time constraint. A test was performed in monitoring a construction yard, obtaining very promising results. Highly realistic and easy-to-interpret 3D models of objects and areas of interest were produced in less than one second, with an accuracy of about 0.5m. For its characteristics, the designed method is suitable for video-surveillance, remote sensing and monitoring, especially in those applications that require intuitive and reliable information quickly, as disasters monitoring, search and rescue and area surveillance.

  2. Optical Coherence Tomography Noise Reduction Using Anisotropic Local Bivariate Gaussian Mixture Prior in 3D Complex Wavelet Domain

    PubMed Central

    Sonka, Milan; Abramoff, Michael D.

    2013-01-01

    In this paper, MMSE estimator is employed for noise-free 3D OCT data recovery in 3D complex wavelet domain. Since the proposed distribution for noise-free data plays a key role in the performance of MMSE estimator, a priori distribution for the pdf of noise-free 3D complex wavelet coefficients is proposed which is able to model the main statistical properties of wavelets. We model the coefficients with a mixture of two bivariate Gaussian pdfs with local parameters which are able to capture the heavy-tailed property and inter- and intrascale dependencies of coefficients. In addition, based on the special structure of OCT images, we use an anisotropic windowing procedure for local parameters estimation that results in visual quality improvement. On this base, several OCT despeckling algorithms are obtained based on using Gaussian/two-sided Rayleigh noise distribution and homomorphic/nonhomomorphic model. In order to evaluate the performance of the proposed algorithm, we use 156 selected ROIs from 650 × 512 × 128 OCT dataset in the presence of wet AMD pathology. Our simulations show that the best MMSE estimator using local bivariate mixture prior is for the nonhomomorphic model in the presence of Gaussian noise which results in an improvement of 7.8 ± 1.7 in CNR. PMID:24222760

  3. Controlling integrin specificity and stem cell differentiation in 2-D and 3-D environments through regulation of fibronectin domain stability

    PubMed Central

    Martino, Mikaël M.; Mochizuki, Mayumi; Rothenfluh, Dominique A.; Rempel, Sandra A.; Hubbell, Jeffrey A.; Barker, Thomas H.

    2009-01-01

    The extracellular matrix (ECM) exerts powerful control over many cellular phenomena, including stem cell differentiation. As such, design and modulation of ECM analogs to ligate specific integrin is a promising approach to control cellular processes in vitro and in vivo for regenerative medicine strategies. Although fibronectin (FN), a crucial ECM protein in tissue development and repair, and its RGD peptide are widely used for cell adhesion, the promiscuity with which they engage integrins leads to difficulty in control of receptor-specific interactions. Recent simulations of force-mediated unfolding of FN domains and sequences analysis of human versus mouse FN suggest that the structural stability of the FN’s central cell-binding domains (FN III9-10) affects its integrin specificity. Through production of FN III9-10 variants with variable stabilities, we obtained ligands that present different specificities for the integrin α5β1 and that can be covalently linked into fibrin matrices. Here, we demonstrate the capacity of α5β1 integrin-specific engagement to influence human mesenchymal stem cell (MSC) behavior in 2D and 3D environments. Our data indicate that α5β1 has an important role in the control of MSC osteogenic differentiation. FN fragments with increased specificity for α5β1 versus αvβ3 results in significantly enhanced osteogenic differentiation of MSCs in 2D and in a clinically relevant 3D fibrin matrix system, although attachment/spreading and proliferation were comparable with that on full-length FN. This work shows how integrin-dependant cellular interactions with the ECM can be engineered to control stem cell fate, within a system appropriate for both 3D cell culture and tissue engineering. PMID:19027948

  4. Advanced in Visualization of 3D Time-Dependent CFD Solutions

    NASA Technical Reports Server (NTRS)

    Lane, David A.; Lasinski, T. A. (Technical Monitor)

    1995-01-01

    Numerical simulations of complex 3D time-dependent (unsteady) flows are becoming increasingly feasible because of the progress in computing systems. Unfortunately, many existing flow visualization systems were developed for time-independent (steady) solutions and do not adequately depict solutions from unsteady flow simulations. Furthermore, most systems only handle one time step of the solutions individually and do not consider the time-dependent nature of the solutions. For example, instantaneous streamlines are computed by tracking the particles using one time step of the solution. However, for streaklines and timelines, particles need to be tracked through all time steps. Streaklines can reveal quite different information about the flow than those revealed by instantaneous streamlines. Comparisons of instantaneous streamlines with dynamic streaklines are shown. For a complex 3D flow simulation, it is common to generate a grid system with several millions of grid points and to have tens of thousands of time steps. The disk requirement for storing the flow data can easily be tens of gigabytes. Visualizing solutions of this magnitude is a challenging problem with today's computer hardware technology. Even interactive visualization of one time step of the flow data can be a problem for some existing flow visualization systems because of the size of the grid. Current approaches for visualizing complex 3D time-dependent CFD solutions are described. The flow visualization system developed at NASA Ames Research Center to compute time-dependent particle traces from unsteady CFD solutions is described. The system computes particle traces (streaklines) by integrating through the time steps. This system has been used by several NASA scientists to visualize their CFD time-dependent solutions. The flow visualization capabilities of this system are described, and visualization results are shown.

  5. Dialog-Based 3D-Image Recognition Using a Domain Ontology

    NASA Astrophysics Data System (ADS)

    Hois, Joana; Wünstel, Michael; Bateman, John A.; Röfer, Thomas

    The combination of vision and speech, together with the resulting necessity for formal representations, builds a central component of an autonomous system. A robot that is supposed to navigate autonomously through space must be able to perceive its environment as automatically as possible. But each recognition system has its own inherent limits. Especially a robot whose task is to navigate through unknown terrain has to deal with unidentified or even unknown objects, thus compounding the recognition problem still further. The system described in this paper takes this into account by trying to identify objects based on their functionality where possible. To handle cases where recognition is insufficient, we examine here two further strategies: on the one hand, the linguistic reference and labeling of the unidentified objects and, on the other hand, ontological deduction. This approach then connects the probabilistic area of object recognition with the logical area of formal reasoning. In order to support formal reasoning, additional relational scene information has to be supplied by the recognition system. Moreover, for a sound ontological basis for these reasoning tasks, it is necessary to define a domain ontology that provides for the representation of real-world objects and their corresponding spatial relations in linguistic and physical respects. Physical spatial relations and objects are measured by the visual system, whereas linguistic spatial relations and objects are required for interactions with a user.

  6. 3D Polarized Radiative Transfer for Solar System Applications Using the public-domain HYPERION Code

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Robitaille, T.; Whitney, B. A.

    2012-12-01

    We present a public-domain radiative transfer tool that will allow researchers to examine a wide-range of interesting solar system applications. Hyperion is a new three-dimensional continuum Monte-Carlo radiative transfer code that is designed to be as general as possible, allowing radiative transfer to be computed through a variety of three-dimensional grids (Robitaille, 2011, Astronomy & Astrophysics 536 A79). The main part of the code is problem-independent, and only requires the user to define the three-dimensional density structure, and the opacity and the illumination properties (as well as a few parameters that control execution and output of the code). Hyperion is written in Fortran 90 and parallelized using the MPI-2 standard. It is bundled with Python libraries that enable very flexible pre- and post-processing options (arbitrary shapes, multiple aerosol components, etc.). These routines are very amenable to user-extensibility. The package is currently distributed at www.hyperion-rt.org. Our presentation will feature 1) a brief overview of the code, including a description of the solar system-specific modifications that we have made beyond the capabilities in the original release; 2) Several solar system applications (i.e., Deep Impact Plume, Martian atmosphere, etc.); 3) discussion of availability and distribution of code components via www.hyperion-rt.org.

  7. Audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI

    NASA Astrophysics Data System (ADS)

    Lee, D.; Greer, P. B.; Arm, J.; Keall, P.; Kim, T.

    2014-03-01

    The purpose of this study was to test the hypothesis that audiovisual (AV) biofeedback can improve image quality and reduce scan time for respiratory-gated 3D thoracic MRI. For five healthy human subjects respiratory motion guidance in MR scans was provided using an AV biofeedback system, utilizing real-time respiratory motion signals. To investigate the improvement of respiratory-gated 3D MR images between free breathing (FB) and AV biofeedback (AV), each subject underwent two imaging sessions. Respiratory-related motion artifacts and imaging time were qualitatively evaluated in addition to the reproducibility of external (abdominal) motion. In the results, 3D MR images in AV biofeedback showed more anatomic information such as a clear distinction of diaphragm, lung lobes and sharper organ boundaries. The scan time was reduced from 401±215 s in FB to 334±94 s in AV (p-value 0.36). The root mean square variation of the displacement and period of the abdominal motion was reduced from 0.4±0.22 cm and 2.8±2.5 s in FB to 0.1±0.15 cm and 0.9±1.3 s in AV (p-value of displacement <0.01 and p-value of period 0.12). This study demonstrated that audiovisual biofeedback improves image quality and reduces scan time for respiratory-gated 3D MRI. These results suggest that AV biofeedback has the potential to be a useful motion management tool in medical imaging and radiation therapy procedures.

  8. Global 3-d weather models for the atmospheric correction of gravity time series

    NASA Astrophysics Data System (ADS)

    Klügel, Thomas; Wziontek, Hartmut

    2016-04-01

    The use of 3-dimensional weather models allows for an effective reduction of atmospheric effects in gravity time series. In the past the BKG service Atmacs (Atmospheric Attraction Computation Service) provided 3-d atmospheric correction time series only for European stations of the International Geodynamics and Earth Tide Service (IGETS, formerly Global Geodynamics Project, GGP), which are based on the high resolution regional model COSMO-EU of the German Weather Service (DWD). The provision of 3-d density data from the global weather models GME (20 km resolution) and most recently ICON (13 km resolution) by the DWD now allows the computation of 3-d atmospheric correction time series for all IGETS stations worldwide. Due to the triangular grid structure, a different procedure for mass elements close to the computation point is necessary. By increasing the spatial resolution towards the computation point by linear interpolation of the grid values, the use of a point mass approach became possible with an approximation error below 0.3 nm/s2. This approach also allows to consider horizontal density gradients and a tilted model surface of the innermost cells. By means of a variance reduction at different frequency bands a significant improvement of the atmospheric correction can be demonstrated at many IGETS stations. The limited temporal resolution of recently 3 hours can be improved by the user by including local air pressure records using a remove-restore technique. Atmospheric correction time series are online available at http://atmacs.bkg.bund.de.

  9. 3D real-time measurement system of seam with laser

    NASA Astrophysics Data System (ADS)

    Huang, Min-shuang; Huang, Jun-fen

    2014-02-01

    3-D Real-time Measurement System of seam outline based on Moiré Projection is proposed and designed. The system is composed of LD, grating, CCD, video A/D, FPGA, DSP and an output interface. The principle and hardware makeup of high-speed and real-time image processing circuit based on a Digital Signal Processor (DSP) and a Field Programmable Gate Array (FPGA) are introduced. Noise generation mechanism in poor welding field conditions is analyzed when Moiré stripes are projected on a welding workpiece surface. Median filter is adopted to smooth the acquired original laser image of seam, and then measurement results of a 3-D outline image of weld groove are provided.

  10. Real-time 3D radiation risk assessment supporting simulation of work in nuclear environments.

    PubMed

    Szőke, I; Louka, M N; Bryntesen, T R; Bratteli, J; Edvardsen, S T; RøEitrheim, K K; Bodor, K

    2014-06-01

    This paper describes the latest developments at the Institute for Energy Technology (IFE) in Norway, in the field of real-time 3D (three-dimensional) radiation risk assessment for the support of work simulation in nuclear environments. 3D computer simulation can greatly facilitate efficient work planning, briefing, and training of workers. It can also support communication within and between work teams, and with advisors, regulators, the media and public, at all the stages of a nuclear installation's lifecycle. Furthermore, it is also a beneficial tool for reviewing current work practices in order to identify possible gaps in procedures, as well as to support the updating of international recommendations, dissemination of experience, and education of the current and future generation of workers.IFE has been involved in research and development into the application of 3D computer simulation and virtual reality (VR) technology to support work in radiological environments in the nuclear sector since the mid 1990s. During this process, two significant software tools have been developed, the VRdose system and the Halden Planner, and a number of publications have been produced to contribute to improving the safety culture in the nuclear industry.This paper describes the radiation risk assessment techniques applied in earlier versions of the VRdose system and the Halden Planner, for visualising radiation fields and calculating dose, and presents new developments towards implementing a flexible and up-to-date dosimetric package in these 3D software tools, based on new developments in the field of radiation protection. The latest versions of these 3D tools are capable of more accurate risk estimation, permit more flexibility via a range of user choices, and are applicable to a wider range of irradiation situations than their predecessors. PMID:24727389

  11. The 3D structure of Kaposi sarcoma herpesvirus LANA C-terminal domain bound to DNA

    PubMed Central

    Hellert, Jan; Weidner-Glunde, Magdalena; Krausze, Joern; Lünsdorf, Heinrich; Ritter, Christiane; Schulz, Thomas F.; Lührs, Thorsten

    2015-01-01

    Kaposi sarcoma herpesvirus (KSHV) persists as a latent nuclear episome in dividing host cells. This episome is tethered to host chromatin to ensure proper segregation during mitosis. For duplication of the latent genome, the cellular replication machinery is recruited. Both of these functions rely on the constitutively expressed latency-associated nuclear antigen (LANA) of the virus. Here, we report the crystal structure of the KSHV LANA DNA-binding domain (DBD) in complex with its high-affinity viral target DNA, LANA binding site 1 (LBS1), at 2.9 Å resolution. In contrast to homologous proteins such as Epstein-Barr virus nuclear antigen 1 (EBNA-1) of the related γ-herpesvirus Epstein-Barr virus, specific DNA recognition by LANA is highly asymmetric. In addition to solving the crystal structure, we found that apart from the two known LANA binding sites, LBS1 and LBS2, LANA also binds to a novel site, denoted LBS3. All three sites are located in a region of the KSHV terminal repeat subunit previously recognized as a minimal replicator. Moreover, we show that the LANA DBD can coat DNA of arbitrary sequence by virtue of a characteristic lysine patch, which is absent in EBNA-1 of the Epstein-Barr virus. Likely, these higher-order assemblies involve the self-association of LANA into supermolecular spirals. One such spiral assembly was solved as a crystal structure of 3.7 Å resolution in the absence of DNA. On the basis of our data, we propose a model for the controlled nucleation of higher-order LANA oligomers that might contribute to the characteristic subnuclear KSHV microdomains (“LANA speckles”), a hallmark of KSHV latency. PMID:25947153

  12. Bi-planar 2D-to-3D registration in Fourier domain for stereoscopic x-ray motion tracking

    NASA Astrophysics Data System (ADS)

    Zosso, Dominique; Le Callennec, Benoît; Bach Cuadra, Meritxell; Aminian, Kamiar; Jolles, Brigitte M.; Thiran, Jean-Philippe

    2008-03-01

    In this paper we present a new method to track bone movements in stereoscopic X-ray image series of the knee joint. The method is based on two different X-ray image sets: a rotational series of acquisitions of the still subject knee that allows the tomographic reconstruction of the three-dimensional volume (model), and a stereoscopic image series of orthogonal projections as the subject performs movements. Tracking the movements of bones throughout the stereoscopic image series means to determine, for each frame, the best pose of every moving element (bone) previously identified in the 3D reconstructed model. The quality of a pose is reflected in the similarity between its theoretical projections and the actual radiographs. We use direct Fourier reconstruction to approximate the three-dimensional volume of the knee joint. Then, to avoid the expensive computation of digitally rendered radiographs (DRR) for pose recovery, we develop a corollary to the 3-dimensional central-slice theorem and reformulate the tracking problem in the Fourier domain. Under the hypothesis of parallel X-ray beams, the heavy 2D-to-3D registration of projections in the signal domain is replaced by efficient slice-to-volume registration in the Fourier domain. Focusing on rotational movements, the translation-relevant phase information can be discarded and we only consider scalar Fourier amplitudes. The core of our motion tracking algorithm can be implemented as a classical frame-wise slice-to-volume registration task. Results on both synthetic and real images confirm the validity of our approach.

  13. A real-time 3D scanning system for pavement distortion inspection

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Xu, Bugao

    2010-01-01

    Pavement distortions, such as rutting and shoving, are the common pavement distress problems that need to be inspected and repaired in a timely manner to ensure ride quality and traffic safety. This paper introduces a real-time, low-cost inspection system devoted to detecting these distress features using high-speed 3D transverse scanning techniques. The detection principle is the dynamic generation and characterization of the 3D pavement profile based on structured light triangulation. To improve the accuracy of the system, a multi-view coplanar scheme is employed in the calibration procedure so that more feature points can be used and distributed across the field of view of the camera. A sub-pixel line extraction method is applied for the laser stripe location, which includes filtering, edge detection and spline interpolation. The pavement transverse profile is then generated from the laser stripe curve and approximated by line segments. The second-order derivatives of the segment endpoints are used to identify the feature points of possible distortions. The system can output the real-time measurements and 3D visualization of rutting and shoving distress in a scanned pavement.

  14. Demonstration of digital hologram recording and 3D-scenes reconstruction in real-time

    NASA Astrophysics Data System (ADS)

    Cheremkhin, Pavel A.; Evtikhiev, Nikolay N.; Krasnov, Vitaly V.; Kulakov, Mikhail N.; Kurbatova, Ekaterina A.; Molodtsov, Dmitriy Y.; Rodin, Vladislav G.

    2016-04-01

    Digital holography is technique that allows to reconstruct information about 2D-objects and 3D-scenes. This is achieved by registration of interference pattern formed by two beams: object and reference ones. Pattern registered by the digital camera is processed. This allows to obtain amplitude and phase of the object beam. Reconstruction of shape of the 2D objects and 3D-scenes can be obtained numerically (using computer) and optically (using spatial light modulators - SLMs). In this work camera Megaplus II ES11000 was used for digital holograms recording. The camera has 4008 × 2672 pixels with sizes of 9 μm × 9 μm. For hologram recording, 50 mW frequency-doubled Nd:YAG laser with wavelength 532 nm was used. Liquid crystal on silicon SLM HoloEye PLUTO VIS was used for optical reconstruction of digital holograms. SLM has 1920 × 1080 pixels with sizes of 8 μm × 8 μm. At objects reconstruction 10 mW He-Ne laser with wavelength 632.8 nm was used. Setups for digital holograms recording and their optical reconstruction with the SLM were combined as follows. MegaPlus Central Control Software allows to display registered frames by the camera with a little delay on the computer monitor. The SLM can work as additional monitor. In result displayed frames can be shown on the SLM display in near real-time. Thus recording and reconstruction of the 3D-scenes was obtained in real-time. Preliminary, resolution of displayed frames was chosen equaled to the SLM one. Quantity of the pixels was limited by the SLM resolution. Frame rate was limited by the camera one. This holographic video setup was applied without additional program implementations that would increase time delays between hologram recording and object reconstruction. The setup was demonstrated for reconstruction of 3D-scenes.

  15. Stochastic finite-difference time-domain

    NASA Astrophysics Data System (ADS)

    Smith, Steven Michael

    2011-12-01

    This dissertation presents the derivation of an approximate method to determine the mean and the variance of electro-magnetic fields in the body using the Finite-Difference Time-Domain (FDTD) method. Unlike Monte Carlo analysis, which requires repeated FDTD simulations, this method directly computes the variance of the fields at every point in space at every sample of time in the simulation. This Stochastic FDTD simulation (S-FDTD) has at its root a new wave called the Variance wave, which is computed in the time domain along with the mean properties of the model space in the FDTD simulation. The Variance wave depends on the electro-magnetic fields, the reflections and transmission though the different dielectrics, and the variances of the electrical properties of the surrounding materials. Like the electro-magnetic fields, the Variance wave begins at zero (there is no variance before the source is turned on) and is computed in the time domain until all fields reach steady state. This process is performed in a fraction of the time of a Monte Carlo simulation and yields the first two statistical parameters (mean and variance). The mean of the field is computed using the traditional FDTD equations. Variance is computed by approximating the correlation coefficients between the constituitive properties and the use of the S-FDTD equations. The impetus for this work was the simulation time it takes to perform 3D Specific Absorption Rate (SAR) FDTD analysis of the human head model for cell phone power absorption in the human head due to the proximity of a cell phone being used. In many instances, Monte Carlo analysis is not performed due to the lengthy simulation times required. With the development of S-FDTD, these statistical analyses could be performed providing valuable statistical information with this information being provided in a small fraction of the time it would take to perform a Monte Carlo analysis.

  16. Laser 3-D measuring system and real-time visual feedback for teaching and correcting breathing

    NASA Astrophysics Data System (ADS)

    Povšič, Klemen; Fležar, Matjaž; Možina, Janez; Jezeršek, Matija

    2012-03-01

    We present a novel method for real-time 3-D body-shape measurement during breathing based on the laser multiple-line triangulation principle. The laser projector illuminates the measured surface with a pattern of 33 equally inclined light planes. Simultaneously, the camera records the distorted light pattern from a different viewpoint. The acquired images are transferred to a personal computer, where the 3-D surface reconstruction, shape analysis, and display are performed in real time. The measured surface displacements are displayed with a color palette, which enables visual feedback to the patient while breathing is being taught. The measuring range is approximately 400×600×500 mm in width, height, and depth, respectively, and the accuracy of the calibrated apparatus is +/-0.7 mm. The system was evaluated by means of its capability to distinguish between different breathing patterns. The accuracy of the measured volumes of chest-wall deformation during breathing was verified using standard methods of volume measurements. The results show that the presented 3-D measuring system with visual feedback has great potential as a diagnostic and training assistance tool when monitoring and evaluating the breathing pattern, because it offers a simple and effective method of graphical communication with the patient.

  17. Web GIS in practice V: 3-D interactive and real-time mapping in Second Life.

    PubMed

    Boulos, Maged N Kamel; Burden, David

    2007-01-01

    This paper describes technologies from Daden Limited for geographically mapping and accessing live news stories/feeds, as well as other real-time, real-world data feeds (e.g., Google Earth KML feeds and GeoRSS feeds) in the 3-D virtual world of Second Life, by plotting and updating the corresponding Earth location points on a globe or some other suitable form (in-world), and further linking those points to relevant information and resources. This approach enables users to visualise, interact with, and even walk or fly through, the plotted data in 3-D. Users can also do the reverse: put pins on a map in the virtual world, and then view the data points on the Web in Google Maps or Google Earth. The technologies presented thus serve as a bridge between mirror worlds like Google Earth and virtual worlds like Second Life. We explore the geo-data display potential of virtual worlds and their likely convergence with mirror worlds in the context of the future 3-D Internet or Metaverse, and reflect on the potential of such technologies and their future possibilities, e.g. their use to develop emergency/public health virtual situation rooms to effectively manage emergencies and disasters in real time. The paper also covers some of the issues associated with these technologies, namely user interface accessibility and individual privacy. PMID:18042275

  18. Web GIS in practice V: 3-D interactive and real-time mapping in Second Life

    PubMed Central

    Boulos, Maged N Kamel; Burden, David

    2007-01-01

    This paper describes technologies from Daden Limited for geographically mapping and accessing live news stories/feeds, as well as other real-time, real-world data feeds (e.g., Google Earth KML feeds and GeoRSS feeds) in the 3-D virtual world of Second Life, by plotting and updating the corresponding Earth location points on a globe or some other suitable form (in-world), and further linking those points to relevant information and resources. This approach enables users to visualise, interact with, and even walk or fly through, the plotted data in 3-D. Users can also do the reverse: put pins on a map in the virtual world, and then view the data points on the Web in Google Maps or Google Earth. The technologies presented thus serve as a bridge between mirror worlds like Google Earth and virtual worlds like Second Life. We explore the geo-data display potential of virtual worlds and their likely convergence with mirror worlds in the context of the future 3-D Internet or Metaverse, and reflect on the potential of such technologies and their future possibilities, e.g. their use to develop emergency/public health virtual situation rooms to effectively manage emergencies and disasters in real time. The paper also covers some of the issues associated with these technologies, namely user interface accessibility and individual privacy. PMID:18042275

  19. 2D array transducers for real-time 3D ultrasound guidance of interventional devices

    NASA Astrophysics Data System (ADS)

    Light, Edward D.; Smith, Stephen W.

    2009-02-01

    We describe catheter ring arrays for real-time 3D ultrasound guidance of devices such as vascular grafts, heart valves and vena cava filters. We have constructed several prototypes operating at 5 MHz and consisting of 54 elements using the W.L. Gore & Associates, Inc. micro-miniature ribbon cables. We have recently constructed a new transducer using a braided wiring technology from Precision Interconnect. This transducer consists of 54 elements at 4.8 MHz with pitch of 0.20 mm and typical -6 dB bandwidth of 22%. In all cases, the transducer and wiring assembly were integrated with an 11 French catheter of a Cook Medical deployment device for vena cava filters. Preliminary in vivo and in vitro testing is ongoing including simultaneous 3D ultrasound and x-ray fluoroscopy.

  20. Parameterization of real-time 3D speckle tracking framework for cardiac strain assessment.

    PubMed

    Lorsakul, Auranuch; Duan, Qi; Po, Ming Jack; Angelini, Elsa; Homma, Shunichi; Laine, Andrew F

    2011-01-01

    Cross-correlation based 3D speckle tracking algorithm can be used to automatically track myocardial motion on three dimensional real-time (RT3D) echocardiography. The goal of this study was to experimentally investigate the effects of different parameters associated with such algorithm to ensure accurate cardiac strain measurements. The investigation was performed on 10 chronic obstructive pulmonary disease RT3DE cardiac ultrasound images. The following two parameters were investigated: 1) the gradient threshold of the anisotropic diffusion pre-filtering and 2) the window size of the cross correlation template matching in the speckle tracking. Results suggest that the optimal gradient threshold of the anisotropic filter depends on the average gradient of the background speckle noise, and that an optimal pair of template size and search window size can be identified determines the cross-correlation level and computational cost. PMID:22254887

  1. Recent advances in 3D time-resolved contrast-enhanced MR angiography.

    PubMed

    Riederer, Stephen J; Haider, Clifton R; Borisch, Eric A; Weavers, Paul T; Young, Phillip M

    2015-07-01

    Contrast-enhanced magnetic resonance angiography (CE-MRA) was first introduced for clinical studies approximately 20 years ago. Early work provided 3-4 mm spatial resolution with acquisition times in the 30-second range. Since that time there has been continuing effort to provide improved spatial resolution with reduced acquisition time, allowing high resolution 3D time-resolved studies. The purpose of this work is to describe how this has been accomplished. Specific technical enablers have been: improved gradients allowing reduced repetition times, improved k-space sampling and reconstruction methods, parallel acquisition, particularly in two directions, and improved and higher count receiver coil arrays. These have collectively made high-resolution time-resolved studies readily available for many anatomic regions. Depending on the application, ∼1 mm isotropic resolution is now possible with frame times of several seconds. Clinical applications of time-resolved CE-MRA are briefly reviewed. PMID:26032598

  2. Recent Advances in 3D Time-Resolved Contrast-Enhanced MR Angiography

    PubMed Central

    Riederer, Stephen J.; Haider, Clifton R.; Borisch, Eric A.; Weavers, Paul T.; Young, Phillip M.

    2015-01-01

    Contrast-enhanced MR angiography (CE-MRA) was first introduced for clinical studies approximately 20 years ago. Early work provided 3 to 4 mm spatial resolution with acquisition times in the 30 sec range. Since that time there has been continuing effort to provide improved spatial resolution with reduced acquisition time, allowing high resolution three-dimensional (3D) time-resolved studies. The purpose of this work is to describe how this has been accomplished. Specific technical enablers have been: improved gradients allowing reduced repetition times, improved k-space sampling and reconstruction methods, parallel acquisition particularly in two directions, and improved and higher count receiver coil arrays. These have collectively made high resolution time-resolved studies readily available for many anatomic regions. Depending on the application, approximate 1 mm isotropic resolution is now possible with frame times of several seconds. Clinical applications of time-resolved CE-MRA are briefly reviewed. PMID:26032598

  3. Time-lapse 3D ground-penetrating radar during plot-scale infiltration experiments

    NASA Astrophysics Data System (ADS)

    Allroggen, Niklas; Jackisch, Conrad; Tronicke, Jens

    2016-04-01

    In electrical resistive soils, surface-based ground-penetrating radar (GPR) is known as the geophysical tool providing the highest spatial resolution. Thus, 2D and 3D GPR surveys are commonly used for imaging subsurface structures or estimating soil moisture content. Due to its sensitivity to soil moisture and its non-invasive character, GPR provides a large potential to monitor soil moisture variation at high temporal and spatial resolution. As shown in previous experiments, the acquisition of time-lapse GPR data under field conditions requires a high data quality in terms of repeatability as well as spatial and temporal resolution. We present hydrogeophysical field experiments at the plot scale (1m x 1m), during which we record time-lapse 3D GPR. For GPR data acquisition, we use a pulseEKKO PRO GPR system equipped with a pair of 500 MHz antennas in combination with a specially designed metal-free measuring platform. Additionally, we collect tracer and soil moisture data, which are used to improve the interpretation of the GPR data with special focus on preferential flow paths and their structured advective flow field. After an accurate time-lapse GPR data processing, we compare 3D reflection events before and after infiltration and quantitatively interpret their relative time-shift in terms of soil moisture variations. Thereby, we are able to account for basically all of the infiltrated water. The first experiments demonstrate the general applicability of our experimental approach but are limited by the number of acquired time steps and measurement during the sprinkling period (the time of the highest temporal dynamics) are not possible at all. Based on this experience we redesign our experimental setup to continuously collect GPR data during irrigation and infiltration. Thereby, we strongly increase the temporal resolution of our measurements, improve the interpretability of the GPR data, and monitor the temporal and spatial dynamics of shallow subsurface

  4. System time-domain simulation

    NASA Technical Reports Server (NTRS)

    Dawson, C. T.; Eggleston, T. W.; Goris, A. C.; Fashano, M.; Paynter, D.; Tranter, W. H.

    1980-01-01

    Complex systems are simulated by engineers without extensive computer experience. Analyst uses free-form engineering-oriented language to input "black box" description. System Time Domain (SYSTID) Simulation Program generates appropriate algorithms and proceeds with simulation. Program is easily linked to postprocessing routines. SYSTID program is written in FORTRAN IV for batch execution and has been implemented on UNIVAC 1110 under control of EXEC 8, Level 31.

  5. A Real-time 3D Visualization of Global MHD Simulation for Space Weather Forecasting

    NASA Astrophysics Data System (ADS)

    Murata, K.; Matsuoka, D.; Kubo, T.; Shimazu, H.; Tanaka, T.; Fujita, S.; Watari, S.; Miyachi, H.; Yamamoto, K.; Kimura, E.; Ishikura, S.

    2006-12-01

    Recently, many satellites for communication networks and scientific observation are launched in the vicinity of the Earth (geo-space). The electromagnetic (EM) environments around the spacecraft are always influenced by the solar wind blowing from the Sun and induced electromagnetic fields. They occasionally cause various troubles or damages, such as electrification and interference, to the spacecraft. It is important to forecast the geo-space EM environment as well as the ground weather forecasting. Owing to the recent remarkable progresses of super-computer technologies, numerical simulations have become powerful research methods in the solar-terrestrial physics. For the necessity of space weather forecasting, NICT (National Institute of Information and Communications Technology) has developed a real-time global MHD simulation system of solar wind-magnetosphere-ionosphere couplings, which has been performed on a super-computer SX-6. The real-time solar wind parameters from the ACE spacecraft at every one minute are adopted as boundary conditions for the simulation. Simulation results (2-D plots) are updated every 1 minute on a NICT website. However, 3D visualization of simulation results is indispensable to forecast space weather more accurately. In the present study, we develop a real-time 3D webcite for the global MHD simulations. The 3-D visualization results of simulation results are updated every 20 minutes in the following three formats: (1)Streamlines of magnetic field lines, (2)Isosurface of temperature in the magnetosphere and (3)Isoline of conductivity and orthogonal plane of potential in the ionosphere. For the present study, we developed a 3-D viewer application working on Internet Explorer browser (ActiveX) is implemented, which was developed on the AVS/Express. Numerical data are saved in the HDF5 format data files every 1 minute. Users can easily search, retrieve and plot past simulation results (3D visualization data and numerical data) by using

  6. V-Man Generation for 3-D Real Time Animation. Chapter 5

    NASA Technical Reports Server (NTRS)

    Nebel, Jean-Christophe; Sibiryakov, Alexander; Ju, Xiangyang

    2007-01-01

    The V-Man project has developed an intuitive authoring and intelligent system to create, animate, control and interact in real-time with a new generation of 3D virtual characters: The V-Men. It combines several innovative algorithms coming from Virtual Reality, Physical Simulation, Computer Vision, Robotics and Artificial Intelligence. Given a high-level task like "walk to that spot" or "get that object", a V-Man generates the complete animation required to accomplish the task. V-Men synthesise motion at runtime according to their environment, their task and their physical parameters, drawing upon its unique set of skills manufactured during the character creation. The key to the system is the automated creation of realistic V-Men, not requiring the expertise of an animator. It is based on real human data captured by 3D static and dynamic body scanners, which is then processed to generate firstly animatable body meshes, secondly 3D garments and finally skinned body meshes.

  7. Flexible time domain averaging technique

    NASA Astrophysics Data System (ADS)

    Zhao, Ming; Lin, Jing; Lei, Yaguo; Wang, Xiufeng

    2013-09-01

    Time domain averaging(TDA) is essentially a comb filter, it cannot extract the specified harmonics which may be caused by some faults, such as gear eccentric. Meanwhile, TDA always suffers from period cutting error(PCE) to different extent. Several improved TDA methods have been proposed, however they cannot completely eliminate the waveform reconstruction error caused by PCE. In order to overcome the shortcomings of conventional methods, a flexible time domain averaging(FTDA) technique is established, which adapts to the analyzed signal through adjusting each harmonic of the comb filter. In this technique, the explicit form of FTDA is first constructed by frequency domain sampling. Subsequently, chirp Z-transform(CZT) is employed in the algorithm of FTDA, which can improve the calculating efficiency significantly. Since the signal is reconstructed in the continuous time domain, there is no PCE in the FTDA. To validate the effectiveness of FTDA in the signal de-noising, interpolation and harmonic reconstruction, a simulated multi-components periodic signal that corrupted by noise is processed by FTDA. The simulation results show that the FTDA is capable of recovering the periodic components from the background noise effectively. Moreover, it can improve the signal-to-noise ratio by 7.9 dB compared with conventional ones. Experiments are also carried out on gearbox test rigs with chipped tooth and eccentricity gear, respectively. It is shown that the FTDA can identify the direction and severity of the eccentricity gear, and further enhances the amplitudes of impulses by 35%. The proposed technique not only solves the problem of PCE, but also provides a useful tool for the fault symptom extraction of rotating machinery.

  8. Probabilistic 3-D time-lapse inversion of magnetotelluric data: application to an enhanced geothermal system

    NASA Astrophysics Data System (ADS)

    Rosas-Carbajal, M.; Linde, N.; Peacock, J.; Zyserman, F. I.; Kalscheuer, T.; Thiel, S.

    2015-12-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved. We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  9. 3D time series analysis of cell shape using Laplacian approaches

    PubMed Central

    2013-01-01

    Background Fundamental cellular processes such as cell movement, division or food uptake critically depend on cells being able to change shape. Fast acquisition of three-dimensional image time series has now become possible, but we lack efficient tools for analysing shape deformations in order to understand the real three-dimensional nature of shape changes. Results We present a framework for 3D+time cell shape analysis. The main contribution is three-fold: First, we develop a fast, automatic random walker method for cell segmentation. Second, a novel topology fixing method is proposed to fix segmented binary volumes without spherical topology. Third, we show that algorithms used for each individual step of the analysis pipeline (cell segmentation, topology fixing, spherical parameterization, and shape representation) are closely related to the Laplacian operator. The framework is applied to the shape analysis of neutrophil cells. Conclusions The method we propose for cell segmentation is faster than the traditional random walker method or the level set method, and performs better on 3D time-series of neutrophil cells, which are comparatively noisy as stacks have to be acquired fast enough to account for cell motion. Our method for topology fixing outperforms the tools provided by SPHARM-MAT and SPHARM-PDM in terms of their successful fixing rates. The different tasks in the presented pipeline for 3D+time shape analysis of cells can be solved using Laplacian approaches, opening the possibility of eventually combining individual steps in order to speed up computations. PMID:24090312

  10. Development of a Wireless and Near Real-Time 3D Ultrasound Strain Imaging System.

    PubMed

    Chen, Zhaohong; Chen, Yongdong; Huang, Qinghua

    2016-04-01

    Ultrasound elastography is an important medical imaging tool for characterization of lesions. In this paper, we present a wireless and near real-time 3D ultrasound strain imaging system. It uses a 3D translating device to control a commercial linear ultrasound transducer to collect pre-compression and post-compression radio-frequency (RF) echo signal frames. The RF frames are wirelessly transferred to a high-performance server via a local area network (LAN). A dynamic programming strain estimation algorithm is implemented with the compute unified device architecture (CUDA) on the graphic processing unit (GPU) in the server to calculate the strain image after receiving a pre-compression RF frame and a post-compression RF frame at the same position. Each strain image is inserted into a strain volume which can be rendered in near real-time. We take full advantage of the translating device to precisely control the probe movement and compression. The GPU-based parallel computing techniques are designed to reduce the computation time. Phantom and in vivo experimental results demonstrate that our system can generate strain volumes with good quality and display an incrementally reconstructed volume image in near real-time. PMID:26954841

  11. A Novel 2D-to-3D Video Conversion Method Using Time-Coherent Depth Maps

    PubMed Central

    Yin, Shouyi; Dong, Hao; Jiang, Guangli; Liu, Leibo; Wei, Shaojun

    2015-01-01

    In this paper, we propose a novel 2D-to-3D video conversion method for 3D entertainment applications. 3D entertainment is getting more and more popular and can be found in many contexts, such as TV and home gaming equipment. 3D image sensors are a new method to produce stereoscopic video content conveniently and at a low cost, and can thus meet the urgent demand for 3D videos in the 3D entertaiment market. Generally, 2D image sensor and 2D-to-3D conversion chip can compose a 3D image sensor. Our study presents a novel 2D-to-3D video conversion algorithm which can be adopted in a 3D image sensor. In our algorithm, a depth map is generated by combining global depth gradient and local depth refinement for each frame of 2D video input. Global depth gradient is computed according to image type while local depth refinement is related to color information. As input 2D video content consists of a number of video shots, the proposed algorithm reuses the global depth gradient of frames within the same video shot to generate time-coherent depth maps. The experimental results prove that this novel method can adapt to different image types, reduce computational complexity and improve the temporal smoothness of generated 3D video. PMID:26131674

  12. A Novel 2D-to-3D Video Conversion Method Using Time-Coherent Depth Maps.

    PubMed

    Yin, Shouyi; Dong, Hao; Jiang, Guangli; Liu, Leibo; Wei, Shaojun

    2015-01-01

    In this paper, we propose a novel 2D-to-3D video conversion method for 3D entertainment applications. 3D entertainment is getting more and more popular and can be found in many contexts, such as TV and home gaming equipment. 3D image sensors are a new method to produce stereoscopic video content conveniently and at a low cost, and can thus meet the urgent demand for 3D videos in the 3D entertaiment market. Generally, 2D image sensor and 2D-to-3D conversion chip can compose a 3D image sensor. Our study presents a novel 2D-to-3D video conversion algorithm which can be adopted in a 3D image sensor. In our algorithm, a depth map is generated by combining global depth gradient and local depth refinement for each frame of 2D video input. Global depth gradient is computed according to image type while local depth refinement is related to color information. As input 2D video content consists of a number of video shots, the proposed algorithm reuses the global depth gradient of frames within the same video shot to generate time-coherent depth maps. The experimental results prove that this novel method can adapt to different image types, reduce computational complexity and improve the temporal smoothness of generated 3D video. PMID:26131674

  13. Time-lapse 3D electrical resistivity tomography to monitor soil-plant interactions

    NASA Astrophysics Data System (ADS)

    Boaga, Jacopo; Rossi, Matteo; Cassiani, Giorgio; Putti, Mario

    2013-04-01

    In this work we present the application of time-lapse non-invasive 3D micro- electrical tomography (ERT) to monitor soil-plant interactions in the root zone in the framework of the FP7 Project CLIMB (Climate Induced Changes on the Hydrology of Mediterranean Basins). The goal of the study is to gain a better understanding of the soil-vegetation interactions by the use of non-invasive techniques. We designed, built and installed a 3D electrical tomography apparatus for the monitoring of the root zone of a single apple tree in an orchard located in the Trentino region, Northern Italy. The micro-ERT apparatus consists of 48 buried electrodes on 4 instrumented micro boreholes plus 24 mini-electrodes on the surface spaced 0.1 m on a square grid. We collected repeated ERT and TDR soil moisture measurements for one year and performed two different controlled irrigation tests: one during a very dry Summer and one during a very wet and highly dynamic plant growing Spring period. We also ran laboratory analyses on soil specimens, in order to evaluate the electrical response at different saturation steps. The results demonstrate that 3D micro-ERT is capable of characterizing subsoil conditions and monitoring root zone activities, especially in terms of root zone suction regions. In particular, we note that in very dry conditions, 3D micro ERT can image water plumes in the shallow subsoil produced by a drip irrigation system. In the very dynamic growing season, under abundant irrigation, micro 3D ERT can detect the main suction zones caused by the tree root activity. Even though the quantitative use of this technique for moisture content balance suffers from well-known inversion difficulties, even the pure imaging of the active root zone is a valuable contribution. However the integration of the measurements in a fully coupled hydrogeophysical inversion is the way forward for a better understanding of subsoil interactions between biomass, hydrosphere and atmosphere.

  14. Biofunctionalization of electrospun PCL-based scaffolds with perlecan domain IV peptide to create a 3-D pharmacokinetic cancer model

    PubMed Central

    Hartman, Olga; Zhang, Chu; Adams, Elizabeth L.; Farach-Carson, Mary C.; Petrelli, Nicholas J.; Chase, Bruce D.; Rabolt, John F.

    2010-01-01

    Because prostate cancer cells metastasize to bone and exhibit osteoblastic features (osteomimicry), the interrelationships between bone-specific microenvironment and prostate cancer cells at sites of bone metastasis are critical to disease progression. In this work the bone marrow microenvironment in vitro was recreated both by tailoring scaffolds physical properties and by functionalizing electrospun polymer fibers with a bioactive peptide derived from domain IV of perlecan heparan sulfate proteoglycan. Electrospun poly (ε-caprolactone) (PCL) fibers and PCL/gelatin composite scaffolds were modified covalently with perlecan domain IV (PlnDIV) peptide. The expression of tight junction protein (E-cadherin) and focal adhesion kinase (FAK) phosphorylation on tyrosine 397 also were investigated. The described bioactive motif significantly enhanced adherence and infiltration of the metastatic prostate cancer cells on all modified electrospun substrates by day 5 post-seeding. Cells cultured on PlnDIV-modified matrices organized stress fibers and increased proliferation at statistically significant rates. Additional findings suggest that presence of PlnDIV peptide in the matrix reduced expression of tight junction protein and binding to PlnDIV peptide was accompanied by increased focal adhesion kinase (FAK) phosphorylation on tyrosine 397. We conclude that PlnDIV peptide supports key signaling events leading to proliferation, survival, and migration of C4-2B cancer cells; hence its incorporation into electrospun matrix is a key improvement to create a successful three-dimensional (3-D) pharmacokinetic cancer model. PMID:20417554

  15. Optimal fourth-order staggered-grid finite-difference scheme for 3D frequency-domain viscoelastic wave modeling

    NASA Astrophysics Data System (ADS)

    Li, Y.; Han, B.; Métivier, L.; Brossier, R.

    2016-09-01

    We investigate an optimal fourth-order staggered-grid finite-difference scheme for 3D frequency-domain viscoelastic wave modeling. An anti-lumped mass strategy is incorporated to minimize the numerical dispersion. The optimal finite-difference coefficients and the mass weighting coefficients are obtained by minimizing the misfit between the normalized phase velocities and the unity. An iterative damped least-squares method, the Levenberg-Marquardt algorithm, is utilized for the optimization. Dispersion analysis shows that the optimal fourth-order scheme presents less grid dispersion and anisotropy than the conventional fourth-order scheme with respect to different Poisson's ratios. Moreover, only 3.7 grid-points per minimum shear wavelength are required to keep the error of the group velocities below 1%. The memory cost is then greatly reduced due to a coarser sampling. A parallel iterative method named CARP-CG is used to solve the large ill-conditioned linear system for the frequency-domain modeling. Validations are conducted with respect to both the analytic viscoacoustic and viscoelastic solutions. Compared with the conventional fourth-order scheme, the optimal scheme generates wavefields having smaller error under the same discretization setups. Profiles of the wavefields are presented to confirm better agreement between the optimal results and the analytic solutions.

  16. GRID2D/3D: A computer program for generating grid systems in complex-shaped two- and three-dimensional spatial domains. Part 2: User's manual and program listing

    NASA Technical Reports Server (NTRS)

    Bailey, R. T.; Shih, T. I.-P.; Nguyen, H. L.; Roelke, R. J.

    1990-01-01

    An efficient computer program, called GRID2D/3D, was developed to generate single and composite grid systems within geometrically complex two- and three-dimensional (2- and 3-D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation in which the distribution of grid points within the spatial domain is controlled by stretching functions. All single grid systems generated by GRID2D/3D can have grid lines that are continuous and differentiable everywhere up to the second-order. Also, grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For continuous composite grid systems, the grid lines are continuous and differentiable everywhere up to the second-order except at interfaces where different single grid systems meet. At interfaces where different single grid systems meet, the grid lines are only differentiable up to the first-order. For 2-D spatial domains, the boundary curves are described by using either cubic or tension spline interpolation. For 3-D spatial domains, the boundary surfaces are described by using either linear Coon's interpolation, bi-hyperbolic spline interpolation, or a new technique referred to as 3-D bi-directional Hermite interpolation. Since grid systems generated by algebraic methods can have grid lines that overlap one another, GRID2D/3D contains a graphics package for evaluating the grid systems generated. With the graphics package, the user can generate grid systems in an interactive manner with the grid generation part of GRID2D/3D. GRID2D/3D is written in FORTRAN 77 and can be run on any IBM PC, XT, or AT compatible computer. In order to use GRID2D/3D on workstations or mainframe computers, some minor modifications must be made in the graphics part of the program; no

  17. Time-dependent 3-D dterministic transport on parallel architectures using Dantsys/MPI

    SciTech Connect

    Baker, R.S.; Alcouffe, R.E.

    1996-12-31

    In addition to the ability to solve the static transport equation, we have also incorporated time dependence into our parallel 3-D S{sub {ital N}} code DANTSYS/MPI. Using a semi-implicit scheme, DANTSYS/MPI is capable of performing time-dependent calculations for both fissioning and pure source driven problems. We have applied this to various types of problems such as nuclear well logging and prompt fission experiments. This paper describes the form of the time- dependent equations implemented, their solution strategies in DANTSYS/MPI including iteration acceleration, and the strategies used for time-step control. Results are presented for a model nuclear well logging calculation.

  18. Real-time tracking with a 3D-Flow processor array

    SciTech Connect

    Crosetto, D.

    1993-06-01

    The problem of real-time track-finding has been performed to date with CAM (Content Addressable Memories) or with fast coincidence logic, because the processing scheme was thought to have much slower performance. Advances in technology together with a new architectural approach make it feasible to also explore the computing technique for real-time track finding thus giving the advantages of implementing algorithms that can find more parameters such as calculate the sagitta, curvature, pt, etc., with respect to the CAM approach. The report describes real-time track finding using new computing approach technique based on the 3D-Flow array processor system. This system consists of a fixed interconnection architecture scheme, allowing flexible algorithm implementation on a scalable platform. The 3D-Flow parallel processing system for track finding is scalable in size and performance by either increasing the number of processors, or increasing the speed or else the number of pipelined stages. The present article describes the conceptual idea and the design stage of the project.

  19. Linear-Time Protein 3-D Structure Searching with Insertions and Deletions

    NASA Astrophysics Data System (ADS)

    Shibuya, Tetsuo; Jansson, Jesper; Sadakane, Kunihiko

    It becomes more and more important to search for similar structures from molecular 3-D structure databases in the structural biology of the post genomic era. Two molecules are said to be similar if the RMSD (root mean square deviation) of the two molecules is less than or equal to some given constant bound. In this paper, we consider an important, fundamental problem of finding all the similar substructures from 3-D structure databases of chain molecules (such as proteins), with consideration of indels (i.e., insertions and deletions). The problem has been believed to be very difficult, but its computational difficulty has not been well known. In this paper, we first show that the same problem in arbitrary dimension is NP-hard. Moreover, we also propose a new algorithm that dramatically improves the average-case time complexity for the problem, in case the number of indels k is bounded by some constant. Our algorithm solves the above problem in average O(N) time, while the time complexity of the best known algorithm was O(Nm k + 1), for a query of size m and a database of size N.

  20. Design and Performance Evaluation on Ultra-Wideband Time-Of-Arrival 3D Tracking System

    NASA Technical Reports Server (NTRS)

    Ni, Jianjun; Arndt, Dickey; Ngo, Phong; Dusl, John

    2012-01-01

    A three-dimensional (3D) Ultra-Wideband (UWB) Time--of-Arrival (TOA) tracking system has been studied at NASA Johnson Space Center (JSC) to provide the tracking capability inside the International Space Station (ISS) modules for various applications. One of applications is to locate and report the location where crew experienced possible high level of carbon-dioxide and felt upset. In order to accurately locate those places in a multipath intensive environment like ISS modules, it requires a robust real-time location system (RTLS) which can provide the required accuracy and update rate. A 3D UWB TOA tracking system with two-way ranging has been proposed and studied. The designed system will be tested in the Wireless Habitat Testbed which simulates the ISS module environment. In this presentation, we discuss the 3D TOA tracking algorithm and the performance evaluation based on different tracking baseline configurations. The simulation results show that two configurations of the tracking baseline are feasible. With 100 picoseconds standard deviation (STD) of TOA estimates, the average tracking error 0.2392 feet (about 7 centimeters) can be achieved for configuration Twisted Rectangle while the average tracking error 0.9183 feet (about 28 centimeters) can be achieved for configuration Slightly-Twisted Top Rectangle . The tracking accuracy can be further improved with the improvement of the STD of TOA estimates. With 10 picoseconds STD of TOA estimates, the average tracking error 0.0239 feet (less than 1 centimeter) can be achieved for configuration "Twisted Rectangle".

  1. MOEMS-based time-of-flight camera for 3D video capturing

    NASA Astrophysics Data System (ADS)

    You, Jang-Woo; Park, Yong-Hwa; Cho, Yong-Chul; Park, Chang-Young; Yoon, Heesun; Lee, Sang-Hun; Lee, Seung-Wan

    2013-03-01

    We suggest a Time-of-Flight (TOF) video camera capturing real-time depth images (a.k.a depth map), which are generated from the fast-modulated IR images utilizing a novel MOEMS modulator having switching speed of 20 MHz. In general, 3 or 4 independent IR (e.g. 850nm) images are required to generate a single frame of depth image. Captured video image of a moving object frequently shows motion drag between sequentially captured IR images, which results in so called `motion blur' problem even when the frame rate of depth image is fast (e.g. 30 to 60 Hz). We propose a novel `single shot' TOF 3D camera architecture generating a single depth image out of synchronized captured IR images. The imaging system constitutes of 2x2 imaging lens array, MOEMS optical shutters (modulator) placed on each lens aperture and a standard CMOS image sensor. The IR light reflected from object is modulated by optical shutters on the apertures of 2x2 lens array and then transmitted images are captured on the image sensor resulting in 2x2 sub-IR images. As a result, the depth image is generated with those simultaneously captured 4 independent sub-IR images, hence the motion blur problem is canceled. The resulting performance is very useful in the applications of 3D camera to a human-machine interaction device such as user interface of TV, monitor, or hand held devices and motion capturing of human body. In addition, we show that the presented 3D camera can be modified to capture color together with depth image simultaneously on `single shot' frame rate.

  2. GRID3D-v2: An updated version of the GRID2D/3D computer program for generating grid systems in complex-shaped three-dimensional spatial domains

    NASA Technical Reports Server (NTRS)

    Steinthorsson, E.; Shih, T. I-P.; Roelke, R. J.

    1991-01-01

    In order to generate good quality systems for complicated three-dimensional spatial domains, the grid-generation method used must be able to exert rather precise controls over grid-point distributions. Several techniques are presented that enhance control of grid-point distribution for a class of algebraic grid-generation methods known as the two-, four-, and six-boundary methods. These techniques include variable stretching functions from bilinear interpolation, interpolating functions based on tension splines, and normalized K-factors. The techniques developed in this study were incorporated into a new version of GRID3D called GRID3D-v2. The usefulness of GRID3D-v2 was demonstrated by using it to generate a three-dimensional grid system in the coolent passage of a radial turbine blade with serpentine channels and pin fins.

  3. Efficient training of convolutional deep belief networks in the frequency domain for application to high-resolution 2D and 3D images.

    PubMed

    Brosch, Tom; Tam, Roger

    2015-01-01

    Deep learning has traditionally been computationally expensive, and advances in training methods have been the prerequisite for improving its efficiency in order to expand its application to a variety of image classification problems. In this letter, we address the problem of efficient training of convolutional deep belief networks by learning the weights in the frequency domain, which eliminates the time-consuming calculation of convolutions. An essential consideration in the design of the algorithm is to minimize the number of transformations to and from frequency space. We have evaluated the running time improvements using two standard benchmark data sets, showing a speed-up of up to 8 times on 2D images and up to 200 times on 3D volumes. Our training algorithm makes training of convolutional deep belief networks on 3D medical images with a resolution of up to 128×128×128 voxels practical, which opens new directions for using deep learning for medical image analysis. PMID:25380341

  4. Real-time computer-generated integral imaging and 3D image calibration for augmented reality surgical navigation.

    PubMed

    Wang, Junchen; Suenaga, Hideyuki; Liao, Hongen; Hoshi, Kazuto; Yang, Liangjing; Kobayashi, Etsuko; Sakuma, Ichiro

    2015-03-01

    Autostereoscopic 3D image overlay for augmented reality (AR) based surgical navigation has been studied and reported many times. For the purpose of surgical overlay, the 3D image is expected to have the same geometric shape as the original organ, and can be transformed to a specified location for image overlay. However, how to generate a 3D image with high geometric fidelity and quantitative evaluation of 3D image's geometric accuracy have not been addressed. This paper proposes a graphics processing unit (GPU) based computer-generated integral imaging pipeline for real-time autostereoscopic 3D display, and an automatic closed-loop 3D image calibration paradigm for displaying undistorted 3D images. Based on the proposed methods, a novel AR device for 3D image surgical overlay is presented, which mainly consists of a 3D display, an AR window, a stereo camera for 3D measurement, and a workstation for information processing. The evaluation on the 3D image rendering performance with 2560×1600 elemental image resolution shows the rendering speeds of 50-60 frames per second (fps) for surface models, and 5-8 fps for large medical volumes. The evaluation of the undistorted 3D image after the calibration yields sub-millimeter geometric accuracy. A phantom experiment simulating oral and maxillofacial surgery was also performed to evaluate the proposed AR overlay device in terms of the image registration accuracy, 3D image overlay accuracy, and the visual effects of the overlay. The experimental results show satisfactory image registration and image overlay accuracy, and confirm the system usability. PMID:25465067

  5. A hybridizable discontinuous Galerkin method combined to a Schwarz algorithm for the solution of 3d time-harmonic Maxwell's equation

    NASA Astrophysics Data System (ADS)

    Li, Liang; Lanteri, Stéphane; Perrussel, Ronan

    2014-01-01

    A Schwarz-type domain decomposition method is presented for the solution of the system of 3d time-harmonic Maxwell's equations. We introduce a hybridizable discontinuous Galerkin (HDG) scheme for the discretization of the problem based on a tetrahedrization of the computational domain. The discrete system of the HDG method on each subdomain is solved by an optimized sparse direct (LU factorization) solver. The solution of the interface system in the domain decomposition framework is accelerated by a Krylov subspace method. The formulation and the implementation of the resulting DD-HDG (Domain Decomposed-Hybridizable Discontinuous Galerkin) method are detailed. Numerical results show that the resulting DD-HDG solution strategy has an optimal convergence rate and can save both CPU time and memory cost compared to a classical upwind flux-based DD-DG (Domain Decomposed-Discontinuous Galerkin) approach.

  6. Implementation of real-time 3D image communication system using stereoscopic imaging and display scheme

    NASA Astrophysics Data System (ADS)

    Kim, Seung-Chul; Kim, Dong-Kyu; Ko, Jung-Hwan; Kim, Eun-Soo

    2004-11-01

    In this paper, a new stereoscopic 3D imaging communication system for real-time teleconferencing application is implemented by using IEEE 1394 digital cameras, Intel Xeon server computer system and Microsoft"s DirectShow programming library and its performance is analyzed in terms of image-grabbing frame rate. In the proposed system, two-view images are captured by using two digital cameras and processed in the Intel Xeon server computer system. And then, disparity data is extracted from them and transmitted to the client system with the left image through an information network and in the recipient two-view images are reconstructed and displayed on the stereoscopic 3D display system. The program for controlling the overall system is developed using the Microsoft DirectShow SDK. From some experimental results, it is found that the proposed system can display stereoscopic images in real-time with a full-color of 16 bits and a frame rate of 15fps.

  7. Single DMD time-multiplexed 64-views autostereoscopic 3D display

    NASA Astrophysics Data System (ADS)

    Loreti, Luigi

    2013-03-01

    Based on previous prototype of the Real time 3D holographic display developed last year, we developed a new concept of auto-stereoscopic multiview display (64 views), wide angle (90°) 3D full color display. The display is based on a RGB laser light source illuminating a DMD (Discovery 4100 0,7") at 24.000 fps, an image deflection system made with an AOD (Acoustic Optic Deflector) driven by a piezo-electric transducer generating a variable standing acoustic wave on the crystal that acts as a phase grating. The DMD projects in fast sequence 64 point of view of the image on the crystal cube. Depending on the frequency of the standing wave, the input picture sent by the DMD is deflected in different angle of view. An holographic screen at a proper distance diffuse the rays in vertical direction (60°) and horizontally select (1°) only the rays directed to the observer. A telescope optical system will enlarge the image to the right dimension. A VHDL firmware to render in real-time (16 ms) 64 views (16 bit 4:2:2) of a CAD model (obj, dxf or 3Ds) and depth-map encoded video images was developed into the resident Virtex5 FPGA of the Discovery 4100 SDK, thus eliminating the needs of image transfer and high speed links

  8. Real-time multicamera system for measurement of 3D coordinates by pattern projection

    NASA Astrophysics Data System (ADS)

    Sainov, Ventseslav; Stoykova, Elena; Harizanova, Jana

    2007-06-01

    The report describes a real-time pattern-projection system for measurement of 3D coordinates with simultaneous illumination and recording of four phase-shifted fringe patterns which are projected at four different wavelengths and captured by four synchronized CCD cameras. This technical solution overcomes the main drawback of the temporal phase-shifting profilometry in which the pattern acquisition is made successively in time. The work considers the use of a sinusoidal phase grating as a projection element which is made by analysis of the frequency content of the projected fringes in the Fresnel diffraction zone and by test measurements of relative 3D coordinates that are performed with interferometrically recorded sinusoidal phase gratings on holographic plates. Finally, operation of a four-wavelength profilometric system with four spatially phase-shifted at π/2 sinusoidal phase gratings illuminated with four diode lasers at wavelengths 790 nm, 810 nm, 850 nm and 910 nm is simulated and the systematical error of the profilometric measurement is evaluated.

  9. Real-Time 3D Magnetic Resonance Imaging of the Pharyngeal Airway in Sleep Apnea

    PubMed Central

    Kim, Yoon-Chul; Lebel, R. Marc; Wu, Ziyue; Davidson Ward, Sally L.; Khoo, Michael C.K.; Nayak, Krishna S.

    2014-01-01

    Purpose To investigate the feasibility of real-time 3D magnetic resonance imaging (MRI) with simultaneous recording of physiological signals for identifying sites of airway obstruction during natural sleep in pediatric patients with sleep-disordered breathing. Methods Experiments were performed using a three-dimensional Fourier transformation (3DFT) gradient echo sequence with prospective undersampling based on golden-angle radial spokes, and L1-norm regularized iterative self-consistent parallel imaging (L1-SPIRiT) reconstruction. This technique was demonstrated in three healthy adult volunteers and five pediatric patients with sleep-disordered breathing. External airway occlusion was used to induce partial collapse of the upper airway on inspiration and test the effectiveness of the proposed imaging method. Apneic events were identified using information available from synchronized recording of mask pressure and respiratory effort. Results Acceptable image quality was obtained in seven of eight subjects. Temporary airway collapse induced via inspiratory loading was successfully imaged in all three volunteers, with average airway volume reductions of 63.3%, 52.5%, and 33.7%. Central apneic events and associated airway narrowing/closure were identified in two pediatric patients. During central apneic events, airway obstruction was observed in the retropalatal region in one pediatric patient. Conclusion Real-time 3D MRI of the pharyngeal airway with synchronized recording of physiological signals is feasible and may provide valuable information about the sites and nature of airway narrowing/collapse during natural sleep. PMID:23788203

  10. Analysis of the repeatability of time-lapse 3d vsp multicomponent surveys, delhi field

    NASA Astrophysics Data System (ADS)

    Carvalho, Mariana Fernandes de

    Delhi Field is a producing oil field located in northeastern Louisiana. In order to monitor the CO2 sweep efficiency, time-lapse 3D seismic data have been acquired in this area. Time-lapse studies are increasingly used to evaluate changes in the seismic response induced by the production of hydrocarbons or the injection of water, CO2 or steam into a reservoir. A 4D seismic signal is generated by a combination of production and injection effects within the reservoir as well as non-repeatability effects. In order to get reliable results from time-lapse seismic methods, it is important to distinguish the production and injection effects from the non-repeatability effects in the 4D seismic signal. Repeatability of 4D land seismic data is affected by several factors. The most significant of them are: source and receiver geometry inaccuracies, differences in seismic sources signatures, variations in the immediate near surface and ambient non-repeatable noise. In this project, two 3D multicomponent VSP surveys acquired in Delhi Field were used to quantify the relative contribution of each factor that can affect the repeatability in land seismic data. The factors analyzed in this study were: source and receiver geometry inaccura- cies, variations in the immediate near surface and ambient non-repeatable noise. This study showed that all these factors had a significant impact on the repeatability of the successive multicomponent VSP surveys in Delhi Field. This project also shows the advantages and disadvantages in the use of different repeata- bility metrics, normalized-root-mean-square (NRMS) difference and signal-to-distortion ratio (SDR) attribute, to evaluate the level of seismic repeatability between successive time-lapse seismic surveys. It is observed that NRMS difference is greatly influenced by time-shifts and that SDR attribute combined with the time-shift may give more distinct and representative repeatability information than the NRMS difference.

  11. Probabilistic 3-D time-lapse inversion of magnetotelluric data: Application to an enhanced geothermal system

    USGS Publications Warehouse

    Rosas-Carbajal, Marina; Linde, Nicolas; Peacock, Jared R.; Zyserman, F. I.; Kalscheuer, Thomas; Thiel, Stephan

    2015-01-01

    Surface-based monitoring of mass transfer caused by injections and extractions in deep boreholes is crucial to maximize oil, gas and geothermal production. Inductive electromagnetic methods, such as magnetotellurics, are appealing for these applications due to their large penetration depths and sensitivity to changes in fluid conductivity and fracture connectivity. In this work, we propose a 3-D Markov chain Monte Carlo inversion of time-lapse magnetotelluric data to image mass transfer following a saline fluid injection. The inversion estimates the posterior probability density function of the resulting plume, and thereby quantifies model uncertainty. To decrease computation times, we base the parametrization on a reduced Legendre moment decomposition of the plume. A synthetic test shows that our methodology is effective when the electrical resistivity structure prior to the injection is well known. The centre of mass and spread of the plume are well retrieved.We then apply our inversion strategy to an injection experiment in an enhanced geothermal system at Paralana, South Australia, and compare it to a 3-D deterministic time-lapse inversion. The latter retrieves resistivity changes that are more shallow than the actual injection interval, whereas the probabilistic inversion retrieves plumes that are located at the correct depths and oriented in a preferential north-south direction. To explain the time-lapse data, the inversion requires unrealistically large resistivity changes with respect to the base model. We suggest that this is partly explained by unaccounted subsurface heterogeneities in the base model from which time-lapse changes are inferred.

  12. Real-time 3D flight guidance with terrain for the X-38

    NASA Astrophysics Data System (ADS)

    Delgado, Frank J.; Abernathy, Michael F.; White, Janis; Lowrey, William H.

    1999-07-01

    The NASA Johnson Space Center is developing a series of prototype flight test vehicles leading to a functional Crew Return Vehicle (CRV). The development of these prototype vehicles, designated as the X-38 program, will demonstrate which technologies are needed to build an inexpensive, safe, and reliable spacecraft that can rapidly return astronauts from onboard the International Space Station (ISS) to earth. These vehicles are being built using an incremental approach and where appropriate, are taking advantage of advanced technologies that may help improve safety, decrease development costs, reduce development time, as well as outperform traditional technologies. This paper discusses the creation of real-time 3-D displays for flight guidance and situation awareness for the X-38 program. These displays feature the incorporation of real-time GPS position data, three-dimensional terrain models, heads-up display (HUD), and landing zone designations. The X-38 crew return vehicle is unique in several ways including that it does not afford the pilot a forward view through a wind screen, and utilizes a parafoil in the final flight phase. As a result, on-board displays to enhance situation awareness face challenges. While real-time flight visualization systems limited to running on high-end workstations have been created, only flight-rated Windows are available as platforms for the X-38 3-D displays. The system has been developed to meet this constraint, as well as those of cost, ease-of-use, reliability and extensibility. Because the X-38 is unpowered, and might be required to enter its landing phase from anywhere on orbit, the display must show, in real-time, and in 3 dimensions, the terrain, ideal and actual glide path, recommended landing areas, as well as typical heads-up information. Maps, such as aeronautical charts, and satellite imagery are optionally overlaid on the 3-D terrain model to provide additional situation awareness. We will present a component

  13. Integrated Interventional Devices For Real Time 3D Ultrasound Imaging and Therapy

    NASA Astrophysics Data System (ADS)

    Smith, Stephen W.; Lee, Warren; Gentry, Kenneth L.; Pua, Eric C.; Light, Edward D.

    2006-05-01

    Two recent advances have expanded the potential of medical ultrasound: the introduction of real-time 3-D ultrasound imaging with catheter, transesophageal and laparoscopic probes and the development of interventional ultrasound therapeutic systems for focused ultrasound surgery, ablation and ultrasound enhanced drug delivery. This work describes devices combining both technologies. A series of transducer probes have been designed, fabricated and tested including: 1) a 12 French side scanning catheter incorporating a 64 element matrix array for imaging at 5MHz and a piston ablation transducer operating at 10 MHz. 2) a 14 Fr forward-scanning catheter integrating a 112 element 2-D array for imaging at 5 MHz encircled by an ablation annulus operating at 10 MHz. Finite element modeling was then used to simulate catheter annular and linear phased array transducers for ablation. 3) Linear phased array transducers were built to confirm the finite element analysis at 4 and 8 MHz including a mechanically focused 86 element 9 MHz array which transmits an ISPTA of 29.3 W/cm2 and creates a lesion in 2 minutes. 4) 2-D arrays of 504 channels operating at 5 MHz have been developed for transesophageal and laparascopic 3D imaging as well as therapeutic heating. All the devices image the heart anatomy including atria, valves, septa and en face views of the pulmonary veins.

  14. SU-E-J-237: Real-Time 3D Anatomy Estimation From Undersampled MR Acquisitions

    SciTech Connect

    Glitzner, M; Lagendijk, J; Raaymakers, B; Crijns, S; Senneville, B Denis de

    2015-06-15

    Recent developments made MRI guided radiotherapy feasible. Performing simultaneous imaging during fractions can provide information about changing anatomy by means of deformable image registration for either immediate plan adaptations or accurate dose accumulation on the changing anatomy. In 3D MRI, however, acquisition time is considerable and scales with resolution. Furthermore, intra-scan motion degrades image quality.In this work, we investigate the sensitivity of registration quality on imageresolution: potentially, by employing spatial undersampling, the acquisition timeof MR images for the purpose of deformable image registration can be reducedsignificantly.On a volunteer, 3D-MR imaging data was sampled in a navigator-gated manner, acquiring one axial volume (360×260×100mm{sup 3}) per 3s during exhale phase. A T1-weighted FFE sequence was used with an acquired voxel size of (2.5mm{sup 3}) for a duration of 17min. Deformation vector fields were evaluated for 100 imaging cycles with respect to the initial anatomy using deformable image registration based on optical flow. Subsequently, the imaging data was downsampled by a factor of 2, simulating a fourfold acquisition speed. Displacements of the downsampled volumes were then calculated by the same process.In kidneyliver boundaries and the region around stomach/duodenum, prominent organ drifts could be observed in both the original and the downsampled imaging data. An increasing displacement of approximately 2mm was observed for the kidney, while an area around the stomach showed sudden displacements of 4mm. Comparison of the motile points over time showed high reproducibility between the displacements of high-resolution and downsampled volumes: over a 17min acquisition, the componentwise RMS error was not more than 0.38mm.Based on the synthetic experiments, 3D nonrigid image registration shows little sensitivity to image resolution and the displacement information is preserved even when halving the

  15. How linguistic and cultural forces shape conceptions of time: English and Mandarin time in 3D.

    PubMed

    Fuhrman, Orly; McCormick, Kelly; Chen, Eva; Jiang, Heidi; Shu, Dingfang; Mao, Shuaimei; Boroditsky, Lera

    2011-01-01

    In this paper we examine how English and Mandarin speakers think about time, and we test how the patterns of thinking in the two groups relate to patterns in linguistic and cultural experience. In Mandarin, vertical spatial metaphors are used more frequently to talk about time than they are in English; English relies primarily on horizontal terms. We present results from two tasks comparing English and Mandarin speakers' temporal reasoning. The tasks measure how people spatialize time in three-dimensional space, including the sagittal (front/back), transverse (left/right), and vertical (up/down) axes. Results of Experiment 1 show that people automatically create spatial representations in the course of temporal reasoning, and these implicit spatializations differ in accordance with patterns in language, even in a non-linguistic task. Both groups showed evidence of a left-to-right representation of time, in accordance with writing direction, but only Mandarin speakers showed a vertical top-to-bottom pattern for time (congruent with vertical spatiotemporal metaphors in Mandarin). Results of Experiment 2 confirm and extend these findings, showing that bilinguals' representations of time depend on both long-term and proximal aspects of language experience. Participants who were more proficient in Mandarin were more likely to arrange time vertically (an effect of previous language experience). Further, bilinguals were more likely to arrange time vertically when they were tested in Mandarin than when they were tested in English (an effect of immediate linguistic context). PMID:21884222

  16. Miniature stereoscopic video system provides real-time 3D registration and image fusion for minimally invasive surgery

    NASA Astrophysics Data System (ADS)

    Yaron, Avi; Bar-Zohar, Meir; Horesh, Nadav

    2007-02-01

    Sophisticated surgeries require the integration of several medical imaging modalities, like MRI and CT, which are three-dimensional. Many efforts are invested in providing the surgeon with this information in an intuitive & easy to use manner. A notable development, made by Visionsense, enables the surgeon to visualize the scene in 3D using a miniature stereoscopic camera. It also provides real-time 3D measurements that allow registration of navigation systems as well as 3D imaging modalities, overlaying these images on the stereoscopic video image in real-time. The real-time MIS 'see through tissue' fusion solutions enable the development of new MIS procedures in various surgical segments, such as spine, abdomen, cardio-thoracic and brain. This paper describes 3D surface reconstruction and registration methods using Visionsense camera, as a step toward fully automated multi-modality 3D registration.

  17. Tornado-like appearance of spontaneous echo contrast assessed by real-time 3D transesophageal echocardiography.

    PubMed

    Otani, Kyoko; Takeuchi, Masaaki; Nakai, Hiromi; Kaku, Kyoko; Haruki, Nobuhiko; Yoshitani, Hidetoshi; Otsuji, Yutaka

    2009-06-01

    We report a case showing that real-time 3D transesophageal echocardiography provides unique information about the dynamic nature of spontaneous echo contrast (SEC) in 3D space and has the potential to provide better understanding of SEC. PMID:27278229

  18. Modelling of 3-D electromagnetic responses using the time-wavenumber method

    SciTech Connect

    Lee, S.

    1991-12-01

    The diffusion of electromagnetic fields in time and the three spatial dimensions can be modelled using a new numerical algorithm that is tailored for geophysical applications. The novel feature of the algorithm is that a large part of the computation is done in the wavenumber domain. Here, the spatial Fourier transforms of the vertical magnetic field and the vertical current density are used to define two scalar potentials. For either a vertical electric or a vertical magnetic dipole source at the subsurface these wavenumber potentials can be represented by a simple Gaussian distribution function. In the air, the fields satisfy the Laplace equation. The flow of this algorithm is as follows: the potentials are defined in the wavenumber domain as an initial condition depending on the source configuration, the vector current density J in space is obtained from the potentials using the inverse Fourier transform, the vector electric field E is obtained by multiplying J by resistivity, the updated potentials are then obtained from the forward Fourier transform of E. Using the updated potential as a subsequent initial condition these steps are repeated until the solution reaches the final time. Since spatial derivatives can be exactly evaluated in the wavenumber domain by simple multiplications, this algorithm requires far less memory than the conventional finite difference (FD) method. The conventional FD method needs finer discretization in space in order to minimize the numerical dispersion caused by numerical differentiation in space. The conductivity distribution for this algorithm is piece-wise continuous and bounded in the wavenumber domain.

  19. Time And Temperature Dependent Micromechanical Properties Of Solder Joints For 3D-Package Integration

    NASA Astrophysics Data System (ADS)

    Roellig, Mike; Meier, Karsten; Metasch, Rene

    2010-11-01

    The recent development of 3D-integrated electronic packages is characterized by the need to increase the diversity of functions and to miniaturize. Currently many 3D-integration concepts are being developed and all of them demand new materials, new designs and new processing technologies. The combination of simulation and experimental investigation becomes increasingly accepted since simulations help to shorten the R&D cycle time and reduce costs. Numerical calculations like the Finite-Element-Method are strong tools to calculate stress conditions in electronic packages resulting from thermal strains due to the manufacturing process and environmental loads. It is essential for the application of numerical calculations that the material data is accurate and describes sufficiently the physical behaviour. The developed machine allows the measurement of time and temperature dependent micromechanical properties of solder joints. Solder joints, which are used to mechanically and electrically connect different packages, are physically measured as they leave the process. This allows accounting for process influences, which may change material properties. Additionally, joint sizes and metallurgical interactions between solder and under bump metallization can be respected by this particular measurement. The measurement allows the determination of material properties within a temperature range of 20° C-200° C. Further, the time dependent creep deformation can be measured within a strain-rate range of 10-31/s-10-81/s. Solder alloys based on Sn-Ag/Sn-Ag-Cu with additionally impurities and joint sizes down to O/ 200 μm were investigated. To finish the material characterization process the material model coefficient were extracted by FEM-Simulation to increase the accuracy of data.

  20. Processing 3D flash LADAR point-clouds in real-time for flight applications

    NASA Astrophysics Data System (ADS)

    Craig, R.; Gravseth, I.; Earhart, R. P.; Bladt, J.; Barnhill, S.; Ruppert, L.; Centamore, C.

    2007-04-01

    Ball Aerospace & Technologies Corp. has demonstrated real-time processing of 3D imaging LADAR point-cloud data to produce the industry's first time-of-flight (TOF) 3D video capability. This capability is uniquely suited to the rigorous demands of space and airborne flight applications and holds great promise in the area of autonomous navigation. It will provide long-range, three dimensional video information to autonomous flight software or pilots for immediate use in rendezvous and docking, proximity operations, landing, surface vision systems, and automatic target recognition and tracking. This is enabled by our new generation of FPGA based "pixel-tube" processors, coprocessors and their associated algorithms which have led to a number of advancements in high-speed wavefront processing along with additional advances in dynamic camera control, and space laser designs based on Ball's CALIPSO LIDAR. This evolution in LADAR is made possible by moving the mechanical complexity required for a scanning system into the electronics, where production, integration, testing and life-cycle costs can be significantly reduced. This technique requires a state of the art TOF read-out integrated circuit (ROIC) attached to a sensor array to collect high resolution temporal data, which is then processed through FPGAs. The number of calculations required to process the data is greatly reduced thanks to the fact that all points are captured at the same time and thus correlated. This correlation allows extremely efficient FPGA processing. This capability has been demonstrated in prototype form at both Marshal Space Flight Center and Langley Research Center on targets that represent docking and landing scenarios. This report outlines many aspects of this work as well as aspects of our recent testing at Marshall's Flight Robotics Laboratory.

  1. Time domain electromagnetic metal detectors

    SciTech Connect

    Hoekstra, P.

    1996-04-01

    This presentation focuses on illustrating by case histories the range of applications and limitations of time domain electromagnetic (TDEM) systems for buried metal detection. Advantages claimed for TDEM metal detectors are: independent of instrument response (Geonics EM61) to surrounding soil and rock type; simple anomaly shape; mitigation of interference by ambient electromagnetic noise; and responsive to both ferrous and non-ferrous metallic targets. The data in all case histories to be presented were acquired with the Geonics EM61 TDEM system. Case histories are a test bed site on Molokai, Hawaii; Fort Monroe, Virginia; and USDOE, Rocky Flats Plant. The present limitations of this technology are: discrimination capabilities in terms of type of ordnance, and depth of burial is limited, and ability of resolving targets with small metallic ambient needs to be improved.

  2. A Real-time, 3D Musculoskeletal Model for Dynamic Simulation of Arm Movements

    PubMed Central

    Chadwick, Edward K.; Blana, Dimitra; van den Bogert, Antonie J.; Kirsch, Robert F.

    2010-01-01

    Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically requires real-time, “patient-in-the-loop” experimentation. A real-time, three-dimensional, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out non-invasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a three degree-of-freedom gleno-humeral joint as well as elbow flexion/extension and pronation/supination, and contains 22 muscles of the shoulder and elbow divided into multiple elements. The model is able to run in real time on modest desktop hardware and demonstrates that a large-scale, 3D model can be made to run in real time. This is a prerequisite for a real-time, whole arm model that will form part of a dynamic arm simulator for use in the development, testing and user training of neural prosthesis systems. PMID:19272926

  3. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallares, V.; Ranero, C. R.

    2012-12-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  4. GATOR: A 3-D time-dependent simulation code for helix TWTs

    SciTech Connect

    Zaidman, E.G.; Freund, H.P.

    1996-12-31

    A 3D nonlinear analysis of helix TWTs is presented. The analysis and simulation code is based upon a spectral decomposition using the vacuum sheath helix modes. The field equations are integrated on a grid and advanced in time using a MacCormack predictor-corrector scheme, and the electron orbit equations are integrated using a fourth order Runge-Kutta algorithm. Charge is accumulated on the grid and the field is interpolated to the particle location by a linear map. The effect of dielectric liners on the vacuum sheath helix dispersion is included in the analysis. Several numerical cases are considered. Simulation of the injection of a DC beam and a signal at a single frequency is compared with a linear field theory of the helix TWT interaction, and good agreement is found.

  5. A 3D space-time motion evaluation for image registration in digital subtraction angiography.

    PubMed

    Taleb, N; Bentoutou, Y; Deforges, O; Taleb, M

    2001-01-01

    In modern clinical practice, Digital Subtraction Angiography (DSA) is a powerful technique for the visualization of blood vessels in a sequence of X-ray images. A serious problem encountered in this technique is the presence of artifacts due to patient motion. The resulting artifacts frequently lead to misdiagnosis or rejection of a DSA image sequence. In this paper, a new technique for removing both global and local motion artifacts is presented. It is based on a 3D space-time motion evaluation for separating pixels changing values because of motion from those changing values because of contrast flow. This technique is proved to be very efficient to correct for patient motion artifacts and is computationally cheap. Experimental results with several clinical data sets show that this technique is very fast and results in higher quality images. PMID:11179698

  6. Real-time 3D vectorcardiography: an application for didactic use

    NASA Astrophysics Data System (ADS)

    Daniel, G.; Lissa, G.; Medina Redondo, D.; Vásquez, L.; Zapata, D.

    2007-11-01

    The traditional approach to teach the physiological basis of electrocardiography, based only on textbooks, turns out to be insufficient or confusing for students of biomedical sciences. The addition of laboratory practice to the curriculum enables students to approach theoretical aspects from a hands-on experience, resulting in a more efficient and deeper knowledge of the phenomena of interest. Here, we present the development of a PC-based application meant to facilitate the understanding of cardiac bioelectrical phenomena by visualizing in real time the instantaneous 3D cardiac vector. The system uses 8 standard leads from a 12-channel electrocardiograph. The application interface has pedagogic objectives, and facilitates the observation of cardiac depolarization and repolarization and its temporal relationship with the ECG, making it simpler to interpret.

  7. IPS - a System for Real-Time Navigation and 3d Modeling

    NASA Astrophysics Data System (ADS)

    Grießbach, D.; Baumbach, D.; Börner, A.; Buder, M.; Ernst, I.; Funk, E.; Wohlfeil, J.; Zuev, S.

    2012-07-01

    fdaReliable navigation and 3D modeling is a necessary requirement for any autonomous system in real world scenarios. German Aerospace Center (DLR) developed a system providing precise information about local position and orientation of a mobile platform as well as three-dimensional information about its environment in real-time. This system, called Integral Positioning System (IPS) can be applied for indoor environments and outdoor environments. To achieve high precision, reliability, integrity and availability a multi-sensor approach was chosen. The important role of sensor data synchronization, system calibration and spatial referencing is emphasized because the data from several sensors has to be fused using a Kalman filter. A hardware operating system (HW-OS) is presented, that facilitates the low-level integration of different interfaces. The benefit of this approach is an increased precision of synchronization at the expense of additional engineering costs. It will be shown that the additional effort is leveraged by the new design concept since the HW-OS methodology allows a proven, flexible and fast design process, a high re-usability of common components and consequently a higher reliability within the low-level sensor fusion. Another main focus of the paper is on IPS software. The DLR developed, implemented and tested a flexible and extensible software concept for data grabbing, efficient data handling, data preprocessing (e.g. image rectification) being essential for thematic data processing. Standard outputs of IPS are a trajectory of the moving platform and a high density 3D point cloud of the current environment. This information is provided in real-time. Based on these results, information processing on more abstract levels can be executed.

  8. 3D Travel Time Prediction for Earthquake Location - An Assessment of Methods and Models

    NASA Astrophysics Data System (ADS)

    Begnaud, M. L.; Ballard, S.; Rowe, C. A.; Young, C. J.; Steck, L.; Hipp, J. R.

    2009-12-01

    We have selected several crustal and mantle 3D models to test for travel-time prediction in a global event location context. Included are the ak135, DoE Unified, Sun et al. (2004) and MITP08 models, among others. Using the recently published tesselated 3D global ray tracing algorithm of Ballard et al., we compare and contrast our travel-time predictions through these obtained models for a set of ~500 Ground Truth (GT) 5 or better events, most of which are chemical or nuclear explosions. We explore the degree of travel-time misfit that can be expected when integrating rays through a model using a different method, or different parameterization, from that which generated the model. For instance, we compare the effect of dynamic ray tracing vs. fixed rays through a mantle tomographic model that was generated by inverting travel-time residuals for pre-calculated, fixed rays in the 1D radial AK135 model. We examine the success of these models for not only teleseismic P arrivals but also Pn and Pg. We explore the geographic biases observed for each phase and the trade-offs encountered when models are integrated. We find that our GT travel times are best predicted through any model when the calculation is perfomed using methods as close as possible to those used in generation of the model, as expected. Such considerations as Earth ellipticity correction and fixed ray vs. dynamic ray tracing need to be applied appropriately for a fair evaluation. Models available to the community are thus of little practical use for global location unless their methods of derivation are also provided, although they may independently provide enlightening images of tectonic features. We conclude that towards our development of a seamless, global model and locator, existing models may best serve as starting models for a global inversion using a single, consistent ray tracing and travel-time calculation approach; thus we view our evaluation of available models as a search for the best starting

  9. Observing molecular dynamics with time-resolved 3D momentum imaging

    NASA Astrophysics Data System (ADS)

    Sturm, F. P.; Wright, T.; Bocharova, I.; Ray, D.; Shivaram, N.; Cryan, J.; Belkacem, A.; Weber, T.; Dörner, R.

    2014-05-01

    Photo-excitation and ionization trigger rich dynamics in molecular systems which play a key role in many important processes in nature such as vision, photosynthesis or photoprotection. Observing those reactions in real-time without significantly disturbing the molecules by a strong electric field has been a great challenge. Recent experiments using Time-of-Flight and Velocity Map Imaging techniques have revealed important information on the dynamics of small molecular systems upon photo-excitation. We have developed an apparatus for time-resolved momentum imaging of electrons and ions in all three spatial dimensions that employs two-color femtosecond laser pulses in the vacuum and extreme ultraviolet (VUV, XUV) for probing molecular dynamics. Our COLTRIMS style reaction microscope can measure electrons and ions in coincidence and reconstruct the momenta of the reaction fragments in 3D. We use a high power 800 nm laser in a loose focusing geometry gas cell to efficinetly drive High Harmonic Generation. The resulting photon flux is sufficient to perform 2-photon pump-probe experiments using VUV and XUV pulses for both pump and probe. With this setup we investigate non-Born-Oppenheimer dynamics in small molecules such as C2H4 and CO2 on a femtosecond time scale. Supported by Chemical Sciences, Geosciences and Biosciences division of BES/DOE.

  10. Computational time analysis of the numerical solution of 3D electrostatic Poisson's equation

    NASA Astrophysics Data System (ADS)

    Kamboh, Shakeel Ahmed; Labadin, Jane; Rigit, Andrew Ragai Henri; Ling, Tech Chaw; Amur, Khuda Bux; Chaudhary, Muhammad Tayyab

    2015-05-01

    3D Poisson's equation is solved numerically to simulate the electric potential in a prototype design of electrohydrodynamic (EHD) ion-drag micropump. Finite difference method (FDM) is employed to discretize the governing equation. The system of linear equations resulting from FDM is solved iteratively by using the sequential Jacobi (SJ) and sequential Gauss-Seidel (SGS) methods, simulation results are also compared to examine the difference between the results. The main objective was to analyze the computational time required by both the methods with respect to different grid sizes and parallelize the Jacobi method to reduce the computational time. In common, the SGS method is faster than the SJ method but the data parallelism of Jacobi method may produce good speedup over SGS method. In this study, the feasibility of using parallel Jacobi (PJ) method is attempted in relation to SGS method. MATLAB Parallel/Distributed computing environment is used and a parallel code for SJ method is implemented. It was found that for small grid size the SGS method remains dominant over SJ method and PJ method while for large grid size both the sequential methods may take nearly too much processing time to converge. Yet, the PJ method reduces computational time to some extent for large grid sizes.

  11. Time Domain Challenges for Exoplanets

    NASA Astrophysics Data System (ADS)

    Dawson, Rebekah Ilene

    2016-01-01

    Over the past couple decades, thousands of extra-solar planets have been discovered orbiting other stars. Most have been detected and characterized using transit and/or radial velocity time series, and these techniques have undergone huge improvements in instrumental precision. However, the improvements in precision have brought to light new statistical challenges in detecting and characterizing exoplanets in the presence of correlated noise caused by stellar activity (transits and radial velocities) and gaps in the time sampling (radial velocities). These challenges have afflicted many of the most interesting exoplanets, from Earth-like planets to planetary systems whose orbital dynamics place important constraints on how planetary systems form and evolve. In the first part of the talk, I will focus on the problem of correlated noise for characterizing transiting exoplanets using transit timing variations. I will present a comparison of several techniques using wavelets, Gaussian processes, and polynomial splines to account for correlated noise in the likelihood function when inferring planetary parameters. I will also present results on the characteristics of correlated noise that cause planets to be missed by the Kepler and homegrown pipelines despite high nominal signal-to-noise. In the second part of the talk, I will focus on the problem of aliasing caused by gaps in the radial-velocity time series on yearly, daily, and monthly timescales. I will present results on identifying aliases in the Fourier domain by taking advantage of aliasing on multiple timescales and discuss the interplay between aliasing and stellar activity for several habitable-zone "planets" that have recently been called into question as possible spurious signals caused by activity. As we push toward detecting and characterizing lower mass planets, it is essential that astrostatistical advances keep pace with advances in instrumentation.

  12. Automatic 2D to 3D conversion implemented for real-time applications

    NASA Astrophysics Data System (ADS)

    Ponomaryov, Volodymyr; Ramos-Diaz, Eduardo; Gonzalez Huitron, Victor

    2014-05-01

    Different hardware implementations of designed automatic 2D to 3D video color conversion employing 2D video sequence are presented. The analyzed framework includes together processing of neighboring frames using the following blocks: CIELa*b* color space conversion, wavelet transform, edge detection using HF wavelet sub-bands (HF, LH and HH), color segmentation via k-means on a*b* color plane, up-sampling, disparity map (DM) estimation, adaptive postfiltering, and finally, the anaglyph 3D scene generation. During edge detection, the Donoho threshold is computed, then each sub-band is binarized according to a threshold chosen and finally the thresholding image is formed. DM estimation is performed in the following matter: in left stereo image (or frame), a window with varying sizes is used according to the information obtained from binarized sub-band image, distinguishing different texture areas into LL sub-band image. The stereo matching is performed between two (left and right) LL sub-band images using processing with different window sizes. Upsampling procedure is employed in order to obtain the enhanced DM. Adaptive post-processing procedure is based on median filter and k-means segmentation in a*b* color plane. The SSIM and QBP criteria are applied in order to compare the performance of the proposed framework against other disparity map computation techniques. The designed technique has been implemented on DSP TMS320DM648, Matlab's Simulink module over a PC with Windows 7 and using graphic card (NVIDIA Quadro K2000) demonstrating that the proposed approach can be applied in real-time processing mode.

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

    NASA Astrophysics Data System (ADS)

    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.

  14. Spread spectrum time domain reflectometry

    NASA Astrophysics Data System (ADS)

    Smith, Paul Samuel

    For many years, wiring has been treated as a system that could be installed and expected to work for the life of the aircraft. As aircraft age far beyond their original expected life span, this attitude is rapidly changing. Wiring problems have recently been identified as the cause of several tragic mishaps and hundreds of thousands of lost mission hours. Intermittent wiring faults have been and continue to be difficult to resolve. Test methods that pinpoint faults on the ground can miss intermittent failures. New test methods involving spread spectrum signals are investigated that could be used in flight to locate intermittent failures, including open circuits, short circuits, and arcs. Spread spectrum time domain reflectometry (SSTDR) and sequence time domain reflectometry (STDR) are analyzed in light of the signals commonly present on aircraft wiring. Pseudo noise codes used for the generation of STDR and SSTDR signals are analyzed for application in a STDR/SSTDR test system in the presence of noise. The effects of Mil-Std 1553 and white noise on the STDR and SSTDR signals are discussed analytically, through simulations, and with the use of test hardware. A test system using STDR and SSTDR is designed, built, and used to collect STDR and SSTDR test data. The data collected with the STDR/SSTDR test hardware is analyzed and compared to the theoretical results. Experimental data for open and short circuits collected using SSTDR and a curve fitting algorithm shows a maximum range estimation error of +/-0.2 ft for 75O coaxial cable up to 100ft, and +/-0.6ft for a sample 32.5ft non-controlled impedance aircraft cable. Mil-Std 1553 is specified to operate reliably with a signal-to-noise ratio of 17.5dB, and the SSTDR test system was able to locate an open circuit on a cable also carrying simulated Mil-Std 1553 data where the SSTDR signal was 50dB below the Mil-Std 1553 signal. STDR and SSTDR are shown to be effective in detecting and locating dry and wet arcs on wires.

  15. In situ visualization of magma deformation at high temperature using time-lapse 3D tomography

    NASA Astrophysics Data System (ADS)

    Godinho, jose; Lee, Peter; Lavallee, Yan; Kendrick, Jackie; Von-Aulock, Felix

    2016-04-01

    We use synchrotron based x-ray computed micro-tomography (sCT) to visualize, in situ, the microstructural evolution of magma samples 3 mm diameter with a resolution of 3 μm during heating and uniaxial compression at temperatures up to 1040 °C. The interaction between crystals, melt and gas bubbles is analysed in 4D (3D + time) during sample deformation. The ability to observe the changes of the microstructure as a function of time allow us to: a) study the effect of temperature in the ability of magma to fracture or deform; b) quantify bubble nucleation and growth rates during heating; c) study the relation between crystal displacement and volatile exsolution. We will show unique beautiful videos of how bubbles grow and coalescence, how samples and crystals within the sample fracture, heal and deform. Our study establishes in situ sCT as a powerful tool to quantify and visualize with micro-scale resolution fast processes taking place in magma that are essential to understand ascent in a volcanic conduit and validate existing models for determining the explosivity of volcanic eruptions. Tracking simultaneously the time and spatial changes of magma microstructures is shown to be primordial to study disequilibrium processes between crystals, melt and gas phases.

  16. Theoretical assessment of a synthetic aperture beamformer for real-time 3-D imaging.

    PubMed

    Hazard, C R; Lockwood, G R

    1999-01-01

    A real-time 3-D imaging system requires the development of a beamformer that can generate many beams simultaneously. In this paper, we discuss and evaluate a suitable synthetic aperture beamformer. The proposed beamformer is based on a pipelined network of high speed digital signal processors (DSP). By using simple interpolation-based beamforming, only a few calculations per pixel are required for each channel, and an entire 2-D synthetic aperture image can be formed in the time of one transmit event. The performance of this beamformer was explored using a computer simulation of the radiation pattern. The simulations were done for a full 64-element array and a sparse array with the same receive aperture but only five transmit elements. We assessed the effects of changing the sampling rate and amplitude quantization by comparing the relative levels of secondary lobes in the radiation patterns. The results show that the proposed beamformer produces a radiation pattern equivalent to a conventional beamformer using baseband demodulation, provided that the sampling rate is approximately 10 times the center frequency of the transducer (34% bandwidth pulse). The simulations also show that the sparse array is not significantly more sensitive to delay or amplitude quantization than the full array. PMID:18238502

  17. Realistic 3D Terrain Roaming and Real-Time Flight Simulation

    NASA Astrophysics Data System (ADS)

    Que, Xiang; Liu, Gang; He, Zhenwen; Qi, Guang

    2014-12-01

    This paper presents an integrate method, which can provide access to current status and the dynamic visible scanning topography, to enhance the interactive during the terrain roaming and real-time flight simulation. A digital elevation model and digital ortho-photo map data integrated algorithm is proposed as the base algorithm for our approach to build a realistic 3D terrain scene. A new technique with help of render to texture and head of display for generating the navigation pane is used. In the flight simulating, in order to eliminate flying "jump", we employs the multidimensional linear interpolation method to adjust the camera parameters dynamically and steadily. Meanwhile, based on the principle of scanning laser imaging, we draw pseudo color figures by scanning topography in different directions according to the real-time flying status. Simulation results demonstrate that the proposed algorithm is prospective for applications and the method can improve the effect and enhance dynamic interaction during the real-time flight.

  18. A real-time 3D scanning system for pavement rutting and pothole detections

    NASA Astrophysics Data System (ADS)

    Li, Qingguang; Yao, Ming; Yao, Xun; Yu, Wurong; Xu, Bugao

    2009-08-01

    Rutting and pothole are the common pavement distress problems that need to be timely inspected and repaired to ensure ride quality and safe traffic. This paper introduces a real-time, automated inspection system devoted for detecting these distress features using high-speed transverse scanning. The detection principle is based on the dynamic generation and characterization of 3D pavement profiles obtained from structured light measurements. The system implementation mainly involves three tasks: multi-view coplanar calibration, sub-pixel laser stripe location, and pavement distress recognition. The multi-view coplanar scheme was employed in the calibration procedure to increase the feature points and to make the points distributed across the field of view of the camera, which greatly improves the calibration precision. The laser stripe locating method was implemented in four steps: median filtering, coarse edge detection, fine edge adjusting, stripe curve mending and interpolation by cubic splines. The pavement distress recognition algorithms include line segment approximation of the profile, searching for the feature points, and parameters calculations. The parameter data of a curve segment between two feature points, such as width, depth and length, were used to differentiate rutting, pothole, and pothole under different constraints. The preliminary experiment results show that the system is capable of locating these pavement distresses, and meets the needs for real-time and accurate pavement inspection.

  19. Controlled Experimental Study Depicting Moving Objects in View-Shared Time-Resolved 3D MRA

    PubMed Central

    Mostardi, Petrice M.; Haider, Clifton R.; Rossman, Phillip J.; Borisch, Eric A.; Riederer, Stephen J.

    2010-01-01

    Various methods have been used for time-resolved contrast-enhanced MRA (CE-MRA), many involving view sharing. However, the extent to which the resultant image time series represents the actual dynamic behavior of the contrast bolus is not always clear. Although numerical simulations can be used to estimate performance, an experimental study can allow more realistic characterization. The purpose of this work was to use a computer-controlled motion phantom for study of the temporal fidelity of 3D time-resolved sequences in depicting a contrast bolus. It is hypothesized that the view order of the acquisition and the selection of views in the reconstruction can affect the positional accuracy and sharpness of the leading edge of the bolus and artifactual signal preceding the edge. Phantom studies were performed using dilute gadolinium-filled vials that were moved along tabletop tracks by a computer-controlled motor. Several view orders were tested, which use view-sharing and Cartesian sampling. Compactness of measuring the k-space center, consistency of view ordering within each reconstruction frame, and sampling the k-space center near the end of the temporal footprint were shown to be important in accurate portrayal of the leading edge of the bolus. A number of findings were confirmed in an in vivo CE-MRA study. PMID:19319897

  20. Controlled experimental study depicting moving objects in view-shared time-resolved 3D MRA.

    PubMed

    Mostardi, Petrice M; Haider, Clifton R; Rossman, Phillip J; Borisch, Eric A; Riederer, Stephen J

    2009-07-01

    Various methods have been used for time-resolved contrast-enhanced magnetic resonance angiography (CE-MRA), many involving view sharing. However, the extent to which the resultant image time series represents the actual dynamic behavior of the contrast bolus is not always clear. Although numerical simulations can be used to estimate performance, an experimental study can allow more realistic characterization. The purpose of this work was to use a computer-controlled motion phantom for study of the temporal fidelity of three-dimensional (3D) time-resolved sequences in depicting a contrast bolus. It is hypothesized that the view order of the acquisition and the selection of views in the reconstruction can affect the positional accuracy and sharpness of the leading edge of the bolus and artifactual signal preceding the edge. Phantom studies were performed using dilute gadolinium-filled vials that were moved along tabletop tracks by a computer-controlled motor. Several view orders were tested using view-sharing and Cartesian sampling. Compactness of measuring the k-space center, consistency of view ordering within each reconstruction frame, and sampling the k-space center near the end of the temporal footprint were shown to be important in accurate portrayal of the leading edge of the bolus. A number of findings were confirmed in an in vivo CE-MRA study. PMID:19319897

  1. 3D multiple optical tweezers based on time-shared scanning with a fast focus tunable lens

    NASA Astrophysics Data System (ADS)

    Tanaka, Yoshio

    2013-02-01

    Three-dimensional controlled manipulation of individual micro-objects requires multiple optical tweezers that can be independently controlled in a 3D working space with high spatiotemporal resolution. Here, the author presents 3D multiple optical tweezers based on a time-shared scanning technique with an electrically focus tunable lens for axial steering and a two-axis steering mirror for lateral steering. Four typical examples of 3D controlled manipulation, including the rotation of a single bead on its axis, are demonstrated in real time. The optical system design and the control method are also described.

  2. Gabor-domain optical coherence microscopy with integrated dual-axis MEMS scanner for fast 3D imaging and metrology

    NASA Astrophysics Data System (ADS)

    Canavesi, Cristina; Cogliati, Andrea; Hayes, Adam; Santhanam, Anand P.; Tankam, Patrice; Rolland, Jannick P.

    2015-10-01

    Fast, robust, nondestructive 3D imaging is needed for characterization of microscopic structures in industrial and clinical applications. A custom micro-electromechanical system (MEMS)-based 2D scanner system was developed to achieve 55 kHz A-scan acquisition in a Gabor-domain optical coherence microscopy (GD-OCM) instrument with a novel multilevel GPU architecture for high-speed imaging. GD-OCM yields high-definition volumetric imaging with dynamic depth of focusing through a bio-inspired liquid lens-based microscope design, which has no moving parts and is suitable for use in a manufacturing setting or in a medical environment. A dual-axis MEMS mirror was chosen to replace two single-axis galvanometer mirrors; as a result, the astigmatism caused by the mismatch between the optical pupil and the scanning location was eliminated and a 12x reduction in volume of the scanning system was achieved. Imaging at an invariant resolution of 2 μm was demonstrated throughout a volume of 1 × 1 × 0.6 mm3, acquired in less than 2 minutes. The MEMS-based scanner resulted in improved image quality, increased robustness and lighter weight of the system - all factors that are critical for on-field deployment. A custom integrated feedback system consisting of a laser diode and a position-sensing detector was developed to investigate the impact of the resonant frequency of the MEMS and the driving signal of the scanner on the movement of the mirror. Results on the metrology of manufactured materials and characterization of tissue samples with GD-OCM are presented.

  3. Data-driven layer-stripping strategy in 3-D joint refraction and reflection travel-time tomography with TOMO3D

    NASA Astrophysics Data System (ADS)

    Meléndez, Adrià; Korenaga, Jun; Sallarès, Valentí; Miniussi, Alain; Ranero, César

    2015-04-01

    We present a new 3-D travel-time tomography code (TOMO3D) for the modelling of active-source seismic data that uses the arrival times of both refracted and reflected seismic phases to derive the propagation velocity distribution and the geometry of reflecting boundaries in the subsurface. The combination of refracted and reflected data provides a denser coverage of the study area. Moreover, because refractions only depend on the velocity parameters, they contribute to the mitigation of the negative effect of the ambiguity between layer thickness and propagation velocity that is intrinsic to the reflections that define these boundaries. This code is based on its renowned 2-D version TOMO2D from which it inherited the methods to solve the forward and inverse problems. The forward travel-time calculations are conducted using a hybrid ray-tracing technique combining the graph or shortest path method and the bending method. The LSQR algorithm is used to perform the iterative inversion of travel-time residuals to update the initial velocity and depth models. In order to cope with the increased computational demand due to the incorporation of the third dimension, the forward problem solver, which takes by far most of the run time (~90%), has been parallelised with a combination of MP and MPI standards. This parallelisation distributes the ray-tracing and travel-time calculations among the available computational resources, allowing the user to set the number of nodes, processors and cores to be used. The code's performance was evaluated with a complex synthetic case simulating a subduction zone. The objective is to retrieve the velocity distribution of both upper and lower plates and the geometry of the interplate and Moho boundaries. Our tomography method is designed to deal with a single reflector per inversion, and we show that a data-driven layer-stripping strategy allows to successfully recover several reflectors in successive inversions. This strategy consists in

  4. Using 3D Simulation of Elastic Wave Propagation in Laplace Domain for Electromagnetic-Seismic Inverse Modeling

    NASA Astrophysics Data System (ADS)

    Petrov, P.; Newman, G. A.

    2010-12-01

    -Fourier domain we had developed 3D code for full-wave field simulation in the elastic media which take into account nonlinearity introduced by free-surface effects. Our approach is based on the velocity-stress formulation. In the contrast to conventional formulation we defined the material properties such as density and Lame constants not at nodal points but within cells. This second order finite differences method formulated in the cell-based grid, generate numerical solutions compatible with analytical ones within the range errors determinate by dispersion analysis. Our simulator will be embedded in an inversion scheme for joint seismic- electromagnetic imaging. It also offers possibilities for preconditioning the seismic wave propagation problems in the frequency domain. References. Shin, C. & Cha, Y. (2009), Waveform inversion in the Laplace-Fourier domain, Geophys. J. Int. 177(3), 1067- 1079. Shin, C. & Cha, Y. H. (2008), Waveform inversion in the Laplace domain, Geophys. J. Int. 173(3), 922-931. Commer, M. & Newman, G. (2008), New advances in three-dimensional controlled-source electromagnetic inversion, Geophys. J. Int. 172(2), 513-535. Newman, G. A., Commer, M. & Carazzone, J. J. (2010), Imaging CSEM data in the presence of electrical anisotropy, Geophysics, in press.

  5. Automatic alignment of standard views in 3D echocardiograms using real-time tracking

    NASA Astrophysics Data System (ADS)

    Orderud, Fredrik; Torp, Hans; Rabben, Stein Inge

    2009-02-01

    In this paper, we present an automatic approach for alignment of standard apical and short-axis slices, and correcting them for out-of-plane motion in 3D echocardiography. This is enabled by using real-time Kalman tracking to perform automatic left ventricle segmentation using a coupled deformable model, consisting of a left ventricle model, as well as structures for the right ventricle and left ventricle outflow tract. Landmark points from the segmented model are then used to generate standard apical and short-axis slices. The slices are automatically updated after tracking in each frame to correct for out-of-plane motion caused by longitudinal shortening of the left ventricle. Results from a dataset of 35 recordings demonstrate the potential for automating apical slice initialization and dynamic short-axis slices. Apical 4-chamber, 2-chamber and long-axis slices are generated based on an assumption of fixed angle between the slices, and short-axis slices are generated so that they follow the same myocardial tissue over the entire cardiac cycle. The error compared to manual annotation was 8.4 +/- 3.5 mm for apex, 3.6 +/- 1.8 mm for mitral valve and 8.4 +/- 7.4 for apical 4-chamber view. The high computational efficiency and automatic behavior of the method enables it to operate in real-time, potentially during image acquisition.

  6. 3D Simulations of the ``Keyhole'' Hohlraum for Shock Timing on NIF

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Marinak, M. M.; Munro, D. H.; Jones, O. S.

    2007-11-01

    Ignition implosions planned for the National Ignition Facility (NIF) require a pulse shape with a carefully designed series of steps, which launch a series of shocks through the ablator and DT fuel. The relative timing of these shocks must be tuned to better than +/- 100ps to maintain the DT fuel on a sufficiently low adiabat. To meet these requirements, pre-ignition tuning experiments using a modified hohlraum geometry are being planned. This modified geometry, known as the ``keyhole'' hohlraum, adds a re-entrant gold cone, which passes through the hohlraum and capsule walls, to provide an optical line-of-sight to directly measure the shocks as they break out of the ablator. In order to assess the surrogacy of this modified geometry, 3D simulations using HYDRA [1] have been performed. The drive conditions and the resulting effect on shock timing in the keyhole hohlraum will be compared with the corresponding results for the standard ignition hohlraum. [1] M.M. Marinak, et al., Phys. Plasmas 8, 2275 (2001).

  7. Geo-Referenced Mapping Using AN Airborne 3d Time-Of Camera

    NASA Astrophysics Data System (ADS)

    Kohoutek, T. K.; Nitsche, M.; Eisenbeiss, H.

    2011-09-01

    This paper presents the first experience of a close range bird's eye view photogrammetry with range imaging (RIM) sensors for the real time generation of high resolution geo-referenced 3D surface models. The aim of this study was to develop a mobile, versatile and less costly outdoor survey methodology to measure natural surfaces compared to the terrestrial laser scanning (TLS). Two commercial RIM cameras (SR4000 by MESA Imaging AG and a CamCube 2.0 by PMDTechnologies GmbH) were mounted on a lightweight crane and on an unmanned aerial vehicle (UAV). The field experiments revealed various challenges in real time deployment of the two state-of-the-art RIM systems, e.g. processing of the large data volume. Acquisition strategy and data processing and first measurements are presented. The precision of the measured distances is less than 1 cm for good conditions. However, the measurement precision degraded under the test conditions due to direct sunlight, strong illumination contrasts and helicopter vibrations.

  8. Real-time sensing of mouth 3-D position and orientation

    NASA Astrophysics Data System (ADS)

    Burdea, Grigore C.; Dunn, Stanley M.; Mallik, Matsumita; Jun, Heesung

    1990-07-01

    A key problem in using digital subtraction radiography in dentistry is the ability to reposition the X-ray source and patient so as to reproduce an identical imaging geometry. In this paper we describe an approach to solving this problem based on real time sensing of the 3-D position and orientation of the patient's mouth. The research described here is part of a program which has a long term goal to develop an automated digital subtraction radiography system. This will allow the patient and X-ray source to be accurately repositioned without the mechanical fixtures that are presently used to preserve the imaging geometry. If we can measure the position and orientation of the mouth, then the desired position of the source can be computed as the product of the transformation matrices describing the desired imaging geometry and the position vector of the targeted tooth. Position and orientation of the mouth is measured by a real time sensing device using low-frequency magnetic field technology. We first present the problem of repositioning the patient and source and then outline our analytic solution. Then we describe an experimental setup to measure the accuracy, reproducibility and resolution of the sensor and present results of preliminary experiments.

  9. Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Andro, Monty; Downey, Alan (Technical Monitor)

    2001-01-01

    For the first time, a physics based computational model has been used to provide a direct description of the effects of the TWT (Traveling Wave Tube) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept amplitude and/or swept frequency data. The fully three-dimensional (3D), time-dependent, TWT interaction model using the electromagnetic code MAFIA is presented. This model is used to investigate assumptions made in TWT black box models used in communication system level simulations. In addition, digital signal performance, including intersymbol interference (ISI), is compared using direct data input into the MAFIA model and using the system level analysis tool, SPW (Signal Processing Worksystem).

  10. Intersymbol Interference Investigations Using a 3D Time-Dependent Traveling Wave Tube Model

    NASA Technical Reports Server (NTRS)

    Kory, Carol L.; Andro, Monty

    2002-01-01

    For the first time, a time-dependent, physics-based computational model has been used to provide a direct description of the effects of the traveling wave tube amplifier (TWTA) on modulated digital signals. The TWT model comprehensively takes into account the effects of frequency dependent AM/AM and AM/PM conversion; gain and phase ripple; drive-induced oscillations; harmonic generation; intermodulation products; and backward waves. Thus, signal integrity can be investigated in the presence of these sources of potential distortion as a function of the physical geometry and operating characteristics of the high power amplifier and the operational digital signal. This method promises superior predictive fidelity compared to methods using TWT models based on swept- amplitude and/or swept-frequency data. First, the TWT model using the three dimensional (3D) electromagnetic code MAFIA is presented. Then, this comprehensive model is used to investigate approximations made in conventional TWT black-box models used in communication system level simulations. To quantitatively demonstrate the effects these approximations have on digital signal performance predictions, including intersymbol interference (ISI), the MAFIA results are compared to the system level analysis tool, Signal Processing Workstation (SPW), using high order modulation schemes including 16 and 64-QAM.

  11. Independent and arbitrary generation of spots in the 3D space domain with computer generated holograms written on a phase-only liquid crystal spatial light modulator

    NASA Astrophysics Data System (ADS)

    Wang, Dong; Zhang, Jian; Xia, Yang; Wang, Hao

    2012-10-01

    An improved multiple independent iterative plane algorithm, based on a projection optimization idea, is proposed for the independent and arbitrary generation of one spot or multiple spots in a speckle-suppressed 3D work-area. Details of the mathematical expressions of the algorithm are given to theoretically show how it is improved for 3D spot generation. Both simulations and experiments are conducted to investigate the performance of the algorithm for independent and arbitrary 3D spot generation in several different cases. Simulation results agree well with experimental results, which validates the effectiveness of the algorithm proposed. Several additional experiments are demonstrated for fast and independent generation of four or more spots in the 3D space domain, which confirms the capabilities and practicalities of the algorithm further.

  12. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    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.

  13. Portable high-intensity focused ultrasound system with 3D electronic steering, real-time cavitation monitoring, and 3D image reconstruction algorithms: a preclinical study in pigs

    PubMed Central

    2014-01-01

    Purpose: The aim of this study was to evaluate the safety and accuracy of a new portable ultrasonography-guided high-intensity focused ultrasound (USg-HIFU) system with a 3-dimensional (3D) electronic steering transducer, a simultaneous ablation and imaging module, real-time cavitation monitoring, and 3D image reconstruction algorithms. Methods: To address the accuracy of the transducer, hydrophones in a water chamber were used to assess the generation of sonic fields. An animal study was also performed in five pigs by ablating in vivo thighs by single-point sonication (n=10) or volume sonication (n=10) and ex vivo kidneys by single-point sonication (n=10). Histological and statistical analyses were performed. Results: In the hydrophone study, peak voltages were detected within 1.0 mm from the targets on the y- and z-axes and within 2.0-mm intervals along the x-axis (z-axis, direction of ultrasound propagation; y- and x-axes, perpendicular to the direction of ultrasound propagation). Twenty-nine of 30 HIFU sessions successfully created ablations at the target. The in vivo porcine thigh study showed only a small discrepancy (width, 0.5-1.1 mm; length, 3.0 mm) between the planning ultrasonograms and the pathological specimens. Inordinate thermal damage was not observed in the adjacent tissues or sonic pathways in the in vivo thigh and ex vivo kidney studies. Conclusion: Our study suggests that this new USg-HIFU system may be a safe and accurate technique for ablating soft tissues and encapsulated organs. PMID:25038809

  14. Reduction of reconstruction time for time-resolved spiral 3D contrast-enhanced magnetic resonance angiography using parallel computing.

    PubMed

    Kressler, Bryan; Spincemaille, Pascal; Prince, Martin R; Wang, Yi

    2006-09-01

    Time-resolved 3D MRI with high spatial and temporal resolution can be achieved using spiral sampling and sliding-window reconstruction. Image reconstruction is computationally intensive because of the need for data regridding, a large number of temporal phases, and multiple RF receiver coils. Inhomogeneity blurring correction for spiral sampling further increases the computational work load by an order of magnitude, hindering the clinical utility of spiral trajectories. In this work the reconstruction time is reduced by a factor of >40 compared to reconstruction using a single processor. This is achieved by using a cluster of 32 commercial off-the-shelf computers, commodity networking hardware, and readily available software. The reconstruction system is demonstrated for time-resolved spiral contrast-enhanced (CE) peripheral MR angiography (MRA), and a reduction of reconstruction time from 80 min to 1.8 min is achieved. PMID:16892189

  15. The compatibility of consumer DLP projectors with time-sequential stereoscopic 3D visualisation

    NASA Astrophysics Data System (ADS)

    Woods, Andrew J.; Rourke, Tegan

    2007-02-01

    A range of advertised "Stereo-Ready" DLP projectors are now available in the market which allow high-quality flickerfree stereoscopic 3D visualization using the time-sequential stereoscopic display method. The ability to use a single projector for stereoscopic viewing offers a range of advantages, including extremely good stereoscopic alignment, and in some cases, portability. It has also recently become known that some consumer DLP projectors can be used for timesequential stereoscopic visualization, however it was not well understood which projectors are compatible and incompatible, what display modes (frequency and resolution) are compatible, and what stereoscopic display quality attributes are important. We conducted a study to test a wide range of projectors for stereoscopic compatibility. This paper reports on the testing of 45 consumer DLP projectors of widely different specifications (brand, resolution, brightness, etc). The projectors were tested for stereoscopic compatibility with various video formats (PAL, NTSC, 480P, 576P, and various VGA resolutions) and video input connections (composite, SVideo, component, and VGA). Fifteen projectors were found to work well at up to 85Hz stereo in VGA mode. Twenty three projectors would work at 60Hz stereo in VGA mode.

  16. Registration of Real-Time 3-D Ultrasound to Tomographic Images of the Abdominal Aorta.

    PubMed

    Brekken, Reidar; Iversen, Daniel Høyer; Tangen, Geir Arne; Dahl, Torbjørn

    2016-08-01

    The purpose of this study was to develop an image-based method for registration of real-time 3-D ultrasound to computed tomography (CT) of the abdominal aorta, targeting future use in ultrasound-guided endovascular intervention. We proposed a method in which a surface model of the aortic wall was segmented from CT, and the approximate initial location of this model relative to the ultrasound volume was manually indicated. The model was iteratively transformed to automatically optimize correspondence to the ultrasound data. Feasibility was studied using data from a silicon phantom and in vivo data from a volunteer with previously acquired CT. Through visual evaluation, the ultrasound and CT data were seen to correspond well after registration. Both aortic lumen and branching arteries were well aligned. The processing was done offline, and the registration took approximately 0.2 s per ultrasound volume. The results encourage further patient studies to investigate accuracy, robustness and clinical value of the approach. PMID:27156015

  17. Joint inversion of 3D crustal structure with ambient noise and earthquake body wave travel time

    NASA Astrophysics Data System (ADS)

    Li, Z.; Ni, S.; Chong, J.; Wang, X.

    2012-12-01

    Surface wave tomography based on the noise correlation function of seismic ambient noise has been widely used in studies of crustal and mantle structure . However, the periods of surface wave dispersions in the ambient noise tomography are typically less than 40 s, which limits its resolution on the lower crust. Travel times of earthquake body waves, such as Sg and SmS, could provide additional constraints to the crustal structure, especially to the lower crust due to the ray paths of SmS traveling through the lower crust twice. Here, we proposed a joint inversion method for 3D crustal structure with ambient noise and earthquake body wave travel time data, with the goal of providing better constraints and resolutions on the whole crust. We constructed the linear equations for joint inversion of crustal S velocity structure with the surface wave dispersion and body wave travel time data, and solved the equations with LSQR algorithm. Different weighting and damping factors, together with smoothing constraints, are adopted for surface wave dispersion and body wave travel time data to fit both dataset simultaneously. Synthetics experiments showed that the joint inversion could resolve the crust structure better than sole tomography of ambient noise or body wave travel time. We conducted the joint inversion around the Yangtze block in the eastern China. Rayleigh wave dispersions are extracted from the seismic ambient noise tomography by Zheng et al (2011) in this area. The body waves (e.g., Sg, SmS, Sn) are coherent to be identified and their travel times are measured with accuracy from high quality waveforms of some recent local earthquakes in this area. In order to minimize the travel time uncertainties, the focal depth and epicenter of these local earthquakes were resolved by depth phases and temporary aftershock observations. The result from joint inversion suggests that the crustal velocity structure, especially the lower crust, was well improved, which not only

  18. tomo3d: a new 3-D joint refraction and reflection travel-time tomography code for active-source seismic data

    NASA Astrophysics Data System (ADS)

    Meléndez, A.; Korenaga, J.; Sallarès, V.; Ranero, C. R.

    2012-04-01

    We present the development state of tomo3d, a code for three-dimensional refraction and reflection travel-time tomography of wide-angle seismic data based on the previous two-dimensional version of the code, tomo2d. The core of both forward and inverse problems is inherited from the 2-D version. The ray tracing is performed by a hybrid method combining the graph and bending methods. The graph method finds an ordered array of discrete model nodes, which satisfies Fermat's principle, that is, whose corresponding travel time is a global minimum within the space of discrete nodal connections. The bending method is then applied to produce a more accurate ray path by using the nodes as support points for an interpolation with beta-splines. Travel time tomography is formulated as an iterative linearized inversion, and each step is solved using an LSQR algorithm. In order to avoid the singularity of the sensitivity kernel and to reduce the instability of inversion, regularization parameters are introduced in the inversion in the form of smoothing and damping constraints. Velocity models are built as 3-D meshes, and velocity values at intermediate locations are obtained by trilinear interpolation within the corresponding pseudo-cubic cell. Meshes are sheared to account for topographic relief. A floating reflector is represented by a 2-D grid, and depths at intermediate locations are calculated by bilinear interpolation within the corresponding square cell. The trade-off between the resolution of the final model and the associated computational cost is controlled by the relation between the selected forward star for the graph method (i.e. the number of nodes that each node considers as its neighbors) and the refinement of the velocity mesh. Including reflected phases is advantageous because it provides a better coverage and allows us to define the geometry of those geological interfaces with velocity contrasts sharp enough to be observed on record sections. The code also

  19. Real-time automated 3D sensing, detection, and recognition of dynamic biological micro-organic events

    NASA Astrophysics Data System (ADS)

    Javidi, Bahram; Yeom, Seokwon; Moon, Inkyu; Daneshpanah, Mehdi

    2006-05-01

    In this paper, we present an overview of three-dimensional (3D) optical imaging techniques for real-time automated sensing, visualization, and recognition of dynamic biological microorganisms. Real time sensing and 3D reconstruction of the dynamic biological microscopic objects can be performed by single-exposure on-line (SEOL) digital holographic microscopy. A coherent 3D microscope-based interferometer is constructed to record digital holograms of dynamic micro biological events. Complex amplitude 3D images of the biological microorganisms are computationally reconstructed at different depths by digital signal processing. Bayesian segmentation algorithms are applied to identify regions of interest for further processing. A number of pattern recognition approaches are addressed to identify and recognize the microorganisms. One uses 3D morphology of the microorganisms by analyzing 3D geometrical shapes which is composed of magnitude and phase. Segmentation, feature extraction, graph matching, feature selection, and training and decision rules are used to recognize the biological microorganisms. In a different approach, 3D technique is used that are tolerant to the varying shapes of the non-rigid biological microorganisms. After segmentation, a number of sampling patches are arbitrarily extracted from the complex amplitudes of the reconstructed 3D biological microorganism. These patches are processed using a number of cost functions and statistical inference theory for the equality of means and equality of variances between the sampling segments. Also, we discuss the possibility of employing computational integral imaging for 3D sensing, visualization, and recognition of biological microorganisms illuminated under incoherent light. Experimental results with several biological microorganisms are presented to illustrate detection, segmentation, and identification of micro biological events.

  20. A two-dimensional time domain near zone to far zone transformation

    NASA Technical Reports Server (NTRS)

    Luebbers, Raymond J.; Ryan, Deirdre; Beggs, John H.; Kunz, Karl S.

    1991-01-01

    In a previous paper, a time domain transformation useful for extrapolating 3-D near zone finite difference time domain (FDTD) results to the far zone was presented. In this paper, the corresponding 2-D transform is outlined. While the 3-D transformation produced a physically observable far zone time domain field, this is not convenient to do directly in 2-D, since a convolution would be required. However, a representative 2-D far zone time domain result can be obtained directly. This result can then be transformed to the frequency domain using a Fast Fourier Transform, corrected with a simple multiplicative factor, and used, for example, to calculate the complex wideband scattering width of a target. If an actual time domain far zone result is required it can be obtained by inverse Fourier transform of the final frequency domain result.

  1. a Cache Design Method for Spatial Information Visualization in 3d Real-Time Rendering Engine

    NASA Astrophysics Data System (ADS)

    Dai, X.; Xiong, H.; Zheng, X.

    2012-07-01

    A well-designed cache system has positive impacts on the 3D real-time rendering engine. As the amount of visualization data getting larger, the effects become more obvious. They are the base of the 3D real-time rendering engine to smoothly browsing through the data, which is out of the core memory, or from the internet. In this article, a new kind of caches which are based on multi threads and large file are introduced. The memory cache consists of three parts, the rendering cache, the pre-rendering cache and the elimination cache. The rendering cache stores the data that is rendering in the engine; the data that is dispatched according to the position of the view point in the horizontal and vertical directions is stored in the pre-rendering cache; the data that is eliminated from the previous cache is stored in the eliminate cache and is going to write to the disk cache. Multi large files are used in the disk cache. When a disk cache file size reaches the limit length(128M is the top in the experiment), no item will be eliminated from the file, but a new large cache file will be created. If the large file number is greater than the maximum number that is pre-set, the earliest file will be deleted from the disk. In this way, only one file is opened for writing and reading, and the rest are read-only so the disk cache can be used in a high asynchronous way. The size of the large file is limited in order to map to the core memory to save loading time. Multi-thread is used to update the cache data. The threads are used to load data to the rendering cache as soon as possible for rendering, to load data to the pre-rendering cache for rendering next few frames, and to load data to the elimination cache which is not necessary for the moment. In our experiment, two threads are designed. The first thread is to organize the memory cache according to the view point, and created two threads: the adding list and the deleting list, the adding list index the data that should be

  2. 3D Printing in the Laboratory: Maximize Time and Funds with Customized and Open-Source Labware.

    PubMed

    Coakley, Meghan; Hurt, Darrell E

    2016-08-01

    3D printing, also known as additive manufacturing, is the computer-guided process of fabricating physical objects by depositing successive layers of material. It has transformed manufacturing across virtually every industry, bringing about incredible advances in research and medicine. The rapidly growing consumer market now includes convenient and affordable "desktop" 3D printers. These are being used in the laboratory to create custom 3D-printed equipment, and a growing community of designers are contributing open-source, cost-effective innovations that can be used by both professionals and enthusiasts. User stories from investigators at the National Institutes of Health and the biomedical research community demonstrate the power of 3D printing to save valuable time and funding. While adoption of 3D printing has been slow in the biosciences to date, the potential is vast. The market predicts that within several years, 3D printers could be commonplace within the home; with so many practical uses for 3D printing, we anticipate that the technology will also play an increasingly important role in the laboratory. PMID:27197798

  3. Efficient near-real-time monitoring of 3D surface displacements in complex landslide scenarios

    NASA Astrophysics Data System (ADS)

    Allasia, Paolo; Manconi, Andrea; Giordan, Daniele; Baldo, Marco; Lollino, Giorgio

    2013-04-01

    Ground deformation measurements play a key role in monitoring activities of landslides. A wide spectrum of instruments and methods is nowadays available, going from in-situ to remote sensing approaches. In emergency scenarios, monitoring is often based on automated instruments capable to achieve accurate measurements, possibly with a very high temporal resolution, in order to achieve the best information about the evolution of the landslide in near-real-time, aiming at early warning purposes. However, the available tools for a rapid and efficient exploitation, understanding and interpretation of the retrieved measurements is still a challenge. This issue is particularly relevant in contexts where monitoring is fundamental to support early warning systems aimed at ensuring safety to people and/or infrastructures. Furthermore, in many cases the results obtained might be of difficult reading and divulgation, especially when people of different backgrounds are involved (e.g. scientists, authorities, civil protection operators, decision makers, etc.). In this work, we extend the concept of automatic and near real time from the acquisition of measurements to the data processing and divulgation, in order to achieve an efficient monitoring of surface displacements in landslide scenarios. We developed an algorithm that allows to go automatically and in near-real-time from the acquisition of 3D displacements on a landslide area to the efficient divulgation of the monitoring results via WEB. This set of straightforward procedures is called ADVICE (ADVanced dIsplaCement monitoring system for Early warning), and has been already successfully applied in several emergency scenarios. The algorithm includes: (i) data acquisition and transfer protocols; (ii) data collection, filtering, and validation; (iii) data analysis and restitution through a set of dedicated software, such as ©3DA [1]; (iv) recognition of displacement/velocity threshold and early warning (v) short term

  4. Real-Time Climate Simulations in the Interactive 3D Game Universe Sandbox ²

    NASA Astrophysics Data System (ADS)

    Goldenson, N. L.

    2014-12-01

    Exploration in an open-ended computer game is an engaging way to explore climate and climate change. Everyone can explore physical models with real-time visualization in the educational simulator Universe Sandbox ² (universesandbox.com/2), which includes basic climate simulations on planets. I have implemented a time-dependent, one-dimensional meridional heat transport energy balance model to run and be adjustable in real time in the midst of a larger simulated system. Universe Sandbox ² is based on the original game - at its core a gravity simulator - with other new physically-based content for stellar evolution, and handling collisions between bodies. Existing users are mostly science enthusiasts in informal settings. We believe that this is the first climate simulation to be implemented in a professionally developed computer game with modern 3D graphical output in real time. The type of simple climate model we've adopted helps us depict the seasonal cycle and the more drastic changes that come from changing the orbit or other external forcings. Users can alter the climate as the simulation is running by altering the star(s) in the simulation, dragging to change orbits and obliquity, adjusting the climate simulation parameters directly or changing other properties like CO2 concentration that affect the model parameters in representative ways. Ongoing visuals of the expansion and contraction of sea ice and snow-cover respond to the temperature calculations, and make it accessible to explore a variety of scenarios and intuitive to understand the output. Variables like temperature can also be graphed in real time. We balance computational constraints with the ability to capture the physical phenomena we wish to visualize, giving everyone access to a simple open-ended meridional energy balance climate simulation to explore and experiment with. The software lends itself to labs at a variety of levels about climate concepts including seasons, the Greenhouse effect

  5. Waveform prediction with travel time model LLNL-G3D assessed by Spectral-Element simulation

    NASA Astrophysics Data System (ADS)

    Morency, C.; Simmons, N. A.; Myers, S. C.; Johannesson, G.; Matzel, E.

    2013-12-01

    Seismic monitoring requires accurate prediction of travel times, amplitudes, and whole waveforms. As a first step towards developing a model that is suited to seismic monitoring, LLNL developed the LLNL-G3D P-wave travel time model (Simmons et al., 2012, JGR) to improve seismic event location accuracy. LLNL-G3D fulfills the need to predict travel times from events occurring anywhere in the globe to stations ranging from local to teleseismic distances. Prediction over this distance range requires explicit inclusion of detailed 3-dimensional structure from Earths surface to the core. An open question is how well a model optimized to fit P-wave travel time data can predict waveforms? We begin to address this question by using the P-wave velocities in LLNL-G3D as a proxy for S-wave velocity and density, then performing waveform simulations via the SPECFEM3D_GLOBE spectral-element code. We assess the ability of LLNL-G3D to predict waveforms and draw comparisons to other 3D models available in SPECFEM3D_GLOBE package and widely used in the scientific community. Although we do not expect the P-wave model to perform as well as waveform based models, we view our effort as a first step towards accurate prediction of time times, amplitudes and full waveforms based on a single model. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  6. Time-lapse 3D VSP monitoring of a carbon dioxide injection project at Delhi Field, Louisiana

    NASA Astrophysics Data System (ADS)

    Lubis, Muhammad Husni Mubarak

    Delhi Field is a producing oil field located in northeastern Louisiana. The estimated original oil in place (OOIP) is 357 mmbo and approximately 54% of OOIP has been produced through the primary production and water-flooding. A CO2-EOR program has been implemented since November 2009 to recover an additional 17% of OOIP. Reservoir surveillance using time-lapse 3D seismic data has been conducted to monitor the CO2 sweep efficiency. The goal of this study is to monitor the CO2 flow-path in the area around the injector using time-lapse 3D VSP data. For this purpose, two 3D VSPs acquired in June 2010 and again in August 2011 were processed together. Fluid substitution and VSP modeling were performed to understand the influence of pore-fluid saturation change on VSP records. A cross-equalization was performed to improve the similarity of the datasets. This step is important to reduce the ambiguity in time-lapse observation. The splice of a 3D VSP image into the surface seismic data becomes the key point in determining the reflector of the reservoir. By integrating the observation from the modeling and the splice of 3D VSP image to surface seismic, the CO2 flow-path from injector 164-3 can be identified from 3D time-lapse VSP data. The CO2 was not radially distributed around the injector, but moved toward southwest direction. This finding is also consistent with the flow-path interpreted from surface seismic. This consistency implies that time-lapse 3D VSP surveys at Delhi Field confirm and augment the time-lapse interpretation from surface seismic data.

  7. On the Finite-Time Splash and Splat Singularities for the 3-D Free-Surface Euler Equations

    NASA Astrophysics Data System (ADS)

    Coutand, Daniel; Shkoller, Steve

    2014-01-01

    We prove that the 3-D free-surface incompressible Euler equations with regular initial geometries and velocity fields have solutions which can form a finite-time "splash" (or "splat") singularity first introduced in Castro et al. (Splash singularity for water waves, http://arxiv.org/abs/1106.2120v2, 2011), wherein the evolving 2-D hypersurface, the moving boundary of the fluid domain, self-intersects at a point (or on surface). Such singularities can occur when the crest of a breaking wave falls unto its trough, or in the study of drop impact upon liquid surfaces. Our approach is founded upon the Lagrangian description of the free-boundary problem, combined with a novel approximation scheme of a finite collection of local coordinate charts; as such we are able to analyze a rather general set of geometries for the evolving 2-D free-surface of the fluid. We do not assume the fluid is irrotational, and as such, our method can be used for a number of other fluid interface problems, including compressible flows, plasmas, as well as the inclusion of surface tension effects.

  8. 3D-Trajectories Adopted by Coding and Regulatory DNA Elements: First-Passage Times for Genomic Interactions

    PubMed Central

    Lucas, Joseph S.; Zhang, Yaojun; Dudko, Olga K.; Murre, Cornelis

    2014-01-01

    SUMMARY During B lymphocyte development, immunoglobulin heavy chain variable (VH), diversity (DH) and joining (JH) segments assemble to generate a diverse antigen receptor repertoire. Here we have marked the distal VH and DH-JH-Eμ regions with Tet-operator binding sites and traced their 3D-trajectories in pro-B cells transduced with a retrovirus encoding Tet-repressor-EGFP. We found that these elements displayed fractional Langevin motion (fLm) due to the viscoelastic hindrance from the surrounding network of proteins and chromatin fibers. Using fractional Langevin dynamics modeling, we found that, with high probability, DHJH elements reach a VH element within minutes. Spatial confinement emerged as the dominant parameter that determined the frequency of such encounters. We propose that the viscoelastic nature of the nuclear environment causes coding elements and regulatory elements to bounce back and forth in a spring-like fashion until specific genomic interactions are established and that spatial confinement of topological domains largely controls first-passage times for genomic interactions. PMID:24998931

  9. Real-time 3D adaptive filtering for portable imaging systems

    NASA Astrophysics Data System (ADS)

    Bockenbach, Olivier; Ali, Murtaza; Wainwright, Ian; Nadeski, Mark

    2015-03-01

    Portable imaging devices have proven valuable for emergency medical services both in the field and hospital environments and are becoming more prevalent in clinical settings where the use of larger imaging machines is impractical. 3D adaptive filtering is one of the most advanced techniques aimed at noise reduction and feature enhancement, but is computationally very demanding and hence often not able to run with sufficient performance on a portable platform. In recent years, advanced multicore DSPs have been introduced that attain high processing performance while maintaining low levels of power dissipation. These processors enable the implementation of complex algorithms like 3D adaptive filtering, improving the image quality of portable medical imaging devices. In this study, the performance of a 3D adaptive filtering algorithm on a digital signal processor (DSP) is investigated. The performance is assessed by filtering a volume of size 512x256x128 voxels sampled at a pace of 10 MVoxels/sec.

  10. Simultaneous elastic parameter inversion in 2-D/3-D TTI medium combined later arrival times

    NASA Astrophysics Data System (ADS)

    Bai, Chao-ying; Wang, Tao; Yang, Shang-bei; Li, Xing-wang; Huang, Guo-jiao

    2016-04-01

    Traditional traveltime inversion for anisotropic medium is, in general, based on a "weak" assumption in the anisotropic property, which simplifies both the forward part (ray tracing is performed once only) and the inversion part (a linear inversion solver is possible). But for some real applications, a general (both "weak" and "strong") anisotropic medium should be considered. In such cases, one has to develop a ray tracing algorithm to handle with the general (including "strong") anisotropic medium and also to design a non-linear inversion solver for later tomography. Meanwhile, it is constructive to investigate how much the tomographic resolution can be improved by introducing the later arrivals. For this motivation, we incorporated our newly developed ray tracing algorithm (multistage irregular shortest-path method) for general anisotropic media with a non-linear inversion solver (a damped minimum norm, constrained least squares problem with a conjugate gradient approach) to formulate a non-linear inversion solver for anisotropic medium. This anisotropic traveltime inversion procedure is able to combine the later (reflected) arrival times. Both 2-D/3-D synthetic inversion experiments and comparison tests show that (1) the proposed anisotropic traveltime inversion scheme is able to recover the high contrast anomalies and (2) it is possible to improve the tomographic resolution by introducing the later (reflected) arrivals, but not as expected in the isotropic medium, because the different velocity (qP, qSV and qSH) sensitivities (or derivatives) respective to the different elastic parameters are not the same but are also dependent on the inclination angle.

  11. New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

    PubMed

    Light, Edward D; Lieu, Victor; Smith, Stephen W

    2009-10-01

    We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication of large numbers of devices. We developed two new fabrication methods that we believe can be used to efficiently manufacture these types of devices in greater than prototype numbers. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter of a Cook Medical, Inc. inferior vena cava (IVC) filter deployment device. We used a braided wiring technology from Tyco Electronics Corp. to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz and the 50 Omega round trip insertion loss was --82 dB. The mean of the nearest neighbor cross talk was -37.0 dB. The second method consisted of a 46-cm long single layer flex circuit from MicroConnex that terminates in an interconnect that plugs directly into our system cable. This transducer had 70 elements at 0.157 mm interelement spacing operating at 4.8 MHz. Typical measured transducer element bandwidth was 29% and the 50 Omega round trip insertion loss was -83 dB. The mean of the nearest neighbor cross talk was -33.0 dB. PMID:20458877

  12. Real Time 3D Echocardiographic Evaluation of Iatrogenic Atrial Septal Defects After Percutaneous Transvenous Mitral Commissurotomy

    PubMed Central

    Devarakonda, Sarath Babu; Mannuva, Boochi Babu; Durgaprasad, Rajasekhar; Velam, Vanajakshamma; Akula, Vidya Sagar; Kasala, Latheef

    2015-01-01

    Introduction: Percutaneous transvenous mitral commissurotomy (PTMC) is a safe and effective procedure for relief of severe mitral stenosis. PTMC is being done widely and many transseptal procedures requiring large diameter catheters, sheaths are becoming popular. The knowledge of iatrogenic atrial septal defect (iASD) is vital. This study assessed the use of real-time 3D echocardiography (RT3DE) and incidence of iASD in a cohort of patients undergoing transseptal catheterization during PTMC. Methods: One hundred ten patients underwent PTMC. The reliability and accuracy of RT3DE for iASD detection was determined, RT3DE was compared with 2D echocardiography (2DE) for iASD occurrence, influencing variables analyzed and followed up for 1 year. Results: RT3DE is more reliable and accurate for the study of iASD than 2DE. Color RT3DE detected iASD in 94 (85.5%), with 2DE iASD was detected in 74 (67.3%) (P < .0001).On follow up 85% had iASD post procedure, 56% at 6 months, 19% at 1 year follow up. The mean iASD diameter was 5.41 ± 3.12 mm and area 6.57 ± 3.81 mm2. iASD correlated with patient height, Wilkins score, pre-PTMC LA ‘v’, and post-PTMC LVEDP. Conclusion: RT3DE imaging is superior in accuracy to traditional 2DE techniques. All the modes of RT3DE are useful in the assessment of iASD. iASD measured by RT3DE correlates with several patient, procedural and echocardiographic variables. PMID:26430495

  13. With the advent of domestic 3-dimensional (3D) printers and their associated reduced cost, is it now time for every medical school to have their own 3D printer?

    PubMed

    Balestrini, Christopher; Campo-Celaya, Tatiana

    2016-01-01

    Anatomy is the backbone of medical education and new techniques to improve learning are frequently explored. With the introduction of 3D printers specifically for the home market, the price of this technology has reached affordable levels. Using patient scan data, accurate 3D models can be printed that represent real human variation in anatomy to provide an innovative, inexpensive and valuable adjunct to anatomical teaching. Is it now time for every medical school to have their own 3D printer? PMID:26383082

  14. A Comprehensive Software System for Interactive, Real-time, Visual 3D Deterministic and Stochastic Groundwater Modeling

    NASA Astrophysics Data System (ADS)

    Li, S.

    2002-05-01

    Taking advantage of the recent developments in groundwater modeling research and computer, image and graphics processing, and objected oriented programming technologies, Dr. Li and his research group have recently developed a comprehensive software system for unified deterministic and stochastic groundwater modeling. Characterized by a new real-time modeling paradigm and improved computational algorithms, the software simulates 3D unsteady flow and reactive transport in general groundwater formations subject to both systematic and "randomly" varying stresses and geological and chemical heterogeneity. The software system has following distinct features and capabilities: Interactive simulation and real time visualization and animation of flow in response to deterministic as well as stochastic stresses. Interactive, visual, and real time particle tracking, random walk, and reactive plume modeling in both systematically and randomly fluctuating flow. Interactive statistical inference, scattered data interpolation, regression, and ordinary and universal Kriging, conditional and unconditional simulation. Real-time, visual and parallel conditional flow and transport simulations. Interactive water and contaminant mass balance analysis and visual and real-time flux update. Interactive, visual, and real time monitoring of head and flux hydrographs and concentration breakthroughs. Real-time modeling and visualization of aquifer transition from confined to unconfined to partially de-saturated or completely dry and rewetting Simultaneous and embedded subscale models, automatic and real-time regional to local data extraction; Multiple subscale flow and transport models Real-time modeling of steady and transient vertical flow patterns on multiple arbitrarily-shaped cross-sections and simultaneous visualization of aquifer stratigraphy, properties, hydrological features (rivers, lakes, wetlands, wells, drains, surface seeps), and dynamically adjusted surface flooding area

  15. A meshless EFG-based algorithm for 3D deformable modeling of soft tissue in real-time.

    PubMed

    Abdi, Elahe; Farahmand, Farzam; Durali, Mohammad

    2012-01-01

    The meshless element-free Galerkin method was generalized and an algorithm was developed for 3D dynamic modeling of deformable bodies in real time. The efficacy of the algorithm was investigated in a 3D linear viscoelastic model of human spleen subjected to a time-varying compressive force exerted by a surgical grasper. The model remained stable in spite of the considerably large deformations occurred. There was a good agreement between the results and those of an equivalent finite element model. The computational cost, however, was much lower, enabling the proposed algorithm to be effectively used in real-time applications. PMID:22356947

  16. Real-time, high-accuracy 3D imaging and shape measurement.

    PubMed

    Nguyen, Hieu; Nguyen, Dung; Wang, Zhaoyang; Kieu, Hien; Le, Minh

    2015-01-01

    In spite of the recent advances in 3D shape measurement and geometry reconstruction, simultaneously achieving fast-speed and high-accuracy performance remains a big challenge in practice. In this paper, a 3D imaging and shape measurement system is presented to tackle such a challenge. The fringe-projection-profilometry-based system employs a number of advanced approaches, such as: composition of phase-shifted fringe patterns, externally triggered synchronization of system components, generalized system setup, ultrafast phase-unwrapping algorithm, flexible system calibration method, robust gamma correction scheme, multithread computation and processing, and graphics-processing-unit-based image display. Experiments have shown that the proposed system can acquire and display high-quality 3D reconstructed images and/or video stream at a speed of 45 frames per second with relative accuracy of 0.04% or at a reduced speed of 22.5 frames per second with enhanced accuracy of 0.01%. The 3D imaging and shape measurement system shows great promise of satisfying the ever-increasing demands of scientific and engineering applications. PMID:25967028

  17. Real-Time Large Scale 3d Reconstruction by Fusing Kinect and Imu Data

    NASA Astrophysics Data System (ADS)

    Huai, J.; Zhang, Y.; Yilmaz, A.

    2015-08-01

    Kinect-style RGB-D cameras have been used to build large scale dense 3D maps for indoor environments. These maps can serve many purposes such as robot navigation, and augmented reality. However, to generate dense 3D maps of large scale environments is still very challenging. In this paper, we present a mapping system for 3D reconstruction that fuses measurements from a Kinect and an inertial measurement unit (IMU) to estimate motion. Our major achievements include: (i) Large scale consistent 3D reconstruction is realized by volume shifting and loop closure; (ii) The coarse-to-fine iterative closest point (ICP) algorithm, the SIFT odometry, and IMU odometry are combined to robustly and precisely estimate pose. In particular, ICP runs routinely to track the Kinect motion. If ICP fails in planar areas, the SIFT odometry provides incremental motion estimate. If both ICP and the SIFT odometry fail, e.g., upon abrupt motion or inadequate features, the incremental motion is estimated by the IMU. Additionally, the IMU also observes the roll and pitch angles which can reduce long-term drift of the sensor assembly. In experiments on a consumer laptop, our system estimates motion at 8Hz on average while integrating color images to the local map and saving volumes of meshes concurrently. Moreover, it is immune to tracking failures, and has smaller drift than the state-of-the-art systems in large scale reconstruction.

  18. Touring Mars Online, Real-time, in 3D for Math and Science Educators and Students

    ERIC Educational Resources Information Center

    Jones, Greg; Kalinowski, Kevin

    2007-01-01

    This article discusses a project that placed over 97% of Mars' topography made available from NASA into an interactive 3D multi-user online learning environment beginning in 2003. In 2005 curriculum materials that were created to support middle school math and science education were developed. Research conducted at the University of North Texas…

  19. Real-time 3D image reconstruction guidance in liver resection surgery

    PubMed Central

    Nicolau, Stephane; Pessaux, Patrick; Mutter, Didier; Marescaux, Jacques

    2014-01-01

    Background Minimally invasive surgery represents one of the main evolutions of surgical techniques. However, minimally invasive surgery adds difficulty that can be reduced through computer technology. Methods From a patient’s medical image [US, computed tomography (CT) or MRI], we have developed an Augmented Reality (AR) system that increases the surgeon’s intraoperative vision by providing a virtual transparency of the patient. AR is based on two major processes: 3D modeling and visualization of anatomical or pathological structures appearing in the medical image, and the registration of this visualization onto the real patient. We have thus developed a new online service, named Visible Patient, providing efficient 3D modeling of patients. We have then developed several 3D visualization and surgical planning software tools to combine direct volume rendering and surface rendering. Finally, we have developed two registration techniques, one interactive and one automatic providing intraoperative augmented reality view. Results From January 2009 to June 2013, 769 clinical cases have been modeled by the Visible Patient service. Moreover, three clinical validations have been realized demonstrating the accuracy of 3D models and their great benefit, potentially increasing surgical eligibility in liver surgery (20% of cases). From these 3D models, more than 50 interactive AR-assisted surgical procedures have been realized illustrating the potential clinical benefit of such assistance to gain safety, but also current limits that automatic augmented reality will overcome. Conclusions Virtual patient modeling should be mandatory for certain interventions that have now to be defined, such as liver surgery. Augmented reality is clearly the next step of the new surgical instrumentation but remains currently limited due to the complexity of organ deformations during surgery. Intraoperative medical imaging used in new generation of automated augmented reality should solve this

  20. iVirtualWorld: A Domain-Oriented End-User Development Environment for Building 3D Virtual Chemistry Experiments

    ERIC Educational Resources Information Center

    Zhong, Ying

    2013-01-01

    Virtual worlds are well-suited for building virtual laboratories for educational purposes to complement hands-on physical laboratories. However, educators may face technical challenges because developing virtual worlds requires skills in programming and 3D design. Current virtual world building tools are developed for users who have programming…

  1. Coupled Neutron-Photon, 3-D, Combinatorial Geometry, Time Dependent, Monte Carlo Transport Code System.

    2013-06-24

    Version 07 TART2012 is a coupled neutron-photon Monte Carlo transport code designed to use three-dimensional (3-D) combinatorial geometry. Neutron and/or photon sources as well as neutron induced photon production can be tracked. It is a complete system to assist you with input preparation, running Monte Carlo calculations, and analysis of output results. TART2012 is also incredibly FAST; if you have used similar codes, you will be amazed at how fast this code is compared tomore » other similar codes. Use of the entire system can save you a great deal of time and energy. TART2012 extends the general utility of the code to even more areas of application than available in previous releases by concentrating on improving the physics, particularly with regard to improved treatment of neutron fission, resonance self-shielding, molecular binding, and extending input options used by the code. Several utilities are included for creating input files and displaying TART results and data. TART2012 uses the latest ENDF/B-VI, Release 8, data. New for TART2012 is the use of continuous energy neutron cross sections, in addition to its traditional multigroup cross sections. For neutron interaction, the data are derived using ENDF-ENDL2005 and include both continuous energy cross sections and 700 group neutron data derived using a combination of ENDF/B-VI, Release 8, and ENDL data. The 700 group structure extends from 10-5 eV up to 1 GeV. Presently nuclear data are only available up to 20 MeV, so that only 616 of the groups are currently used. For photon interaction, 701 point photon data were derived using the Livermore EPDL97 file. The new 701 point structure extends from 100 eV up to 1 GeV, and is currently used over this entire energy range. TART2012 completely supersedes all older versions of TART, and it is strongly recommended that one use only the most recent version of TART2012 and its data files. Check author’s homepage for related information: http

  2. 3D time-lapse analysis of Rab11/FIP5 complex: spatiotemporal dynamics during apical lumen formation.

    PubMed

    Mangan, Anthony; Prekeris, Rytis

    2015-01-01

    Fluorescent imaging of fixed cells grown in two-dimensional (2D) cultures is one of the most widely used techniques for observing protein localization and distribution within cells. Although this technique can also be applied to polarized epithelial cells that form three-dimensional (3D) cysts when grown in a Matrigel matrix suspension, there are still significant limitations in imaging cells fixed at a particular point in time. Here, we describe the use of 3D time-lapse imaging of live cells to observe the dynamics of apical membrane initiation site (AMIS) formation and lumen expansion in polarized epithelial cells. PMID:25800842

  3. Combining Public Domain and Professional Panoramic Imagery for the Accurate and Dense 3d Reconstruction of the Destroyed Bel Temple in Palmyra

    NASA Astrophysics Data System (ADS)

    Wahbeh, W.; Nebiker, S.; Fangi, G.

    2016-06-01

    This paper exploits the potential of dense multi-image 3d reconstruction of destroyed cultural heritage monuments by either using public domain touristic imagery only or by combining the public domain imagery with professional panoramic imagery. The focus of our work is placed on the reconstruction of the temple of Bel, one of the Syrian heritage monuments, which was destroyed in September 2015 by the so called "Islamic State". The great temple of Bel is considered as one of the most important religious buildings of the 1st century AD in the East with a unique design. The investigations and the reconstruction were carried out using two types of imagery. The first are freely available generic touristic photos collected from the web. The second are panoramic images captured in 2010 for documenting those monuments. In the paper we present a 3d reconstruction workflow for both types of imagery using state-of-the art dense image matching software, addressing the non-trivial challenges of combining uncalibrated public domain imagery with panoramic images with very wide base-lines. We subsequently investigate the aspects of accuracy and completeness obtainable from the public domain touristic images alone and from the combination with spherical panoramas. We furthermore discuss the challenges of co-registering the weakly connected 3d point cloud fragments resulting from the limited coverage of the touristic photos. We then describe an approach using spherical photogrammetry as a virtual topographic survey allowing the co-registration of a detailed and accurate single 3d model of the temple interior and exterior.

  4. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing

    PubMed Central

    Yang, Samuel J.; Allen, William E.; Kauvar, Isaac; Andalman, Aaron S.; Young, Noah P.; Kim, Christina K.; Marshel, James H.; Wetzstein, Gordon; Deisseroth, Karl

    2016-01-01

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly—requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging. PMID:26699047

  5. Extended field-of-view and increased-signal 3D holographic illumination with time-division multiplexing.

    PubMed

    Yang, Samuel J; Allen, William E; Kauvar, Isaac; Andalman, Aaron S; Young, Noah P; Kim, Christina K; Marshel, James H; Wetzstein, Gordon; Deisseroth, Karl

    2015-12-14

    Phase spatial light modulators (SLMs) are widely used for generating multifocal three-dimensional (3D) illumination patterns, but these are limited to a field of view constrained by the pixel count or size of the SLM. Further, with two-photon SLM-based excitation, increasing the number of focal spots penalizes the total signal linearly--requiring more laser power than is available or can be tolerated by the sample. Here we analyze and demonstrate a method of using galvanometer mirrors to time-sequentially reposition multiple 3D holograms, both extending the field of view and increasing the total time-averaged two-photon signal. We apply our approach to 3D two-photon in vivo neuronal calcium imaging. PMID:26699047

  6. Real-time forecasting of Hong Kong beach water quality by 3D deterministic model.

    PubMed

    Chan, S N; Thoe, W; Lee, J H W

    2013-03-15

    Bacterial level (e.g. Escherichia coli) is generally adopted as the key indicator of beach water quality due to its high correlation with swimming associated illnesses. A 3D deterministic hydrodynamic model is developed to provide daily water quality forecasting for eight marine beaches in Tsuen Wan, which are only about 8 km from the Harbour Area Treatment Scheme (HATS) outfall discharging 1.4 million m(3)/d of partially-treated sewage. The fate and transport of the HATS effluent and its impact on the E. coli level at nearby beaches are studied. The model features the seamless coupling of near field jet mixing and the far field transport and dispersion of wastewater discharge from submarine outfalls, and a spatial-temporal dependent E. coli decay rate formulation specifically developed for sub-tropical Hong Kong waters. The model prediction of beach water quality has been extensively validated against field data both before and after disinfection of the HATS effluent. Compared with daily beach E. coli data during August-November 2011, the model achieves an overall accuracy of 81-91% in forecasting compliance/exceedance of beach water quality standard. The 3D deterministic model has been most valuable in the interpretation of the complex variation of beach water quality which depends on tidal level, solar radiation and other hydro-meteorological factors. The model can also be used in optimization of disinfection dosage and in emergency response situations. PMID:23337883

  7. Learning Dictionaries of Sparse Codes of 3D Movements of Body Joints for Real-Time Human Activity Understanding

    PubMed Central

    Qi, Jin; Yang, Zhiyong

    2014-01-01

    Real-time human activity recognition is essential for human-robot interactions for assisted healthy independent living. Most previous work in this area is performed on traditional two-dimensional (2D) videos and both global and local methods have been used. Since 2D videos are sensitive to changes of lighting condition, view angle, and scale, researchers begun to explore applications of 3D information in human activity understanding in recently years. Unfortunately, features that work well on 2D videos usually don't perform well on 3D videos and there is no consensus on what 3D features should be used. Here we propose a model of human activity recognition based on 3D movements of body joints. Our method has three steps, learning dictionaries of sparse codes of 3D movements of joints, sparse coding, and classification. In the first step, space-time volumes of 3D movements of body joints are obtained via dense sampling and independent component analysis is then performed to construct a dictionary of sparse codes for each activity. In the second step, the space-time volumes are projected to the dictionaries and a set of sparse histograms of the projection coefficients are constructed as feature representations of the activities. Finally, the sparse histograms are used as inputs to a support vector machine to recognize human activities. We tested this model on three databases of human activities and found that it outperforms the state-of-the-art algorithms. Thus, this model can be used for real-time human activity recognition in many applications. PMID:25473850

  8. Learning dictionaries of sparse codes of 3D movements of body joints for real-time human activity understanding.

    PubMed

    Qi, Jin; Yang, Zhiyong

    2014-01-01

    Real-time human activity recognition is essential for human-robot interactions for assisted healthy independent living. Most previous work in this area is performed on traditional two-dimensional (2D) videos and both global and local methods have been used. Since 2D videos are sensitive to changes of lighting condition, view angle, and scale, researchers begun to explore applications of 3D information in human activity understanding in recently years. Unfortunately, features that work well on 2D videos usually don't perform well on 3D videos and there is no consensus on what 3D features should be used. Here we propose a model of human activity recognition based on 3D movements of body joints. Our method has three steps, learning dictionaries of sparse codes of 3D movements of joints, sparse coding, and classification. In the first step, space-time volumes of 3D movements of body joints are obtained via dense sampling and independent component analysis is then performed to construct a dictionary of sparse codes for each activity. In the second step, the space-time volumes are projected to the dictionaries and a set of sparse histograms of the projection coefficients are constructed as feature representations of the activities. Finally, the sparse histograms are used as inputs to a support vector machine to recognize human activities. We tested this model on three databases of human activities and found that it outperforms the state-of-the-art algorithms. Thus, this model can be used for real-time human activity recognition in many applications. PMID:25473850

  9. Real-time 3-D shape measurement with composite phase-shifting fringes and multi-view system.

    PubMed

    Tao, Tianyang; Chen, Qian; Da, Jian; Feng, Shijie; Hu, Yan; Zuo, Chao

    2016-09-01

    In recent years, fringe projection has become an established and essential method for dynamic three-dimensional (3-D) shape measurement in different fields such as online inspection and real-time quality control. Numerous high-speed 3-D shape measurement methods have been developed by either employing high-speed hardware, minimizing the number of pattern projection, or both. However, dynamic 3-D shape measurement of arbitrarily-shaped objects with full sensor resolution without the necessity of additional pattern projections is still a big challenge. In this work, we introduce a high-speed 3-D shape measurement technique based on composite phase-shifting fringes and a multi-view system. The geometry constraint is adopted to search the corresponding points independently without additional images. Meanwhile, by analysing the 3-D position and the main wrapped phase of the corresponding point, pairs with an incorrect 3-D position or a considerable phase difference are effectively rejected. All of the qualified corresponding points are then corrected, and the unique one as well as the related period order is selected through the embedded triangular wave. Finally, considering that some points can only be captured by one of the cameras due to the occlusions, these points may have different fringe orders in the two views, so a left-right consistency check is employed to eliminate those erroneous period orders in this case. Several experiments on both static and dynamic scenes are performed, verifying that our method can achieve a speed of 120 frames per second (fps) with 25-period fringe patterns for fast, dense, and accurate 3-D measurement. PMID:27607632

  10. Application of 3D WebGIS and real-time technique in earthquake information publishing and visualization

    NASA Astrophysics Data System (ADS)

    Li, Boren; Wu, Jianping; Pan, Mao; Huang, Jing

    2015-06-01

    In hazard management, earthquake researchers have utilized GIS to ease the process of managing disasters. Researchers use WebGIS to assess hazards and seismic risk. Although they can provide a visual analysis platform based on GIS technology, they lack a general description in the extensibility of WebGIS for processing dynamic data, especially real-time data. In this paper, we propose a novel approach for real-time 3D visual earthquake information publishing model based on WebGIS and digital globe to improve the ability of processing real-time data in systems based on WebGIS. On the basis of the model, we implement a real-time 3D earthquake information publishing system—EqMap3D. The system can not only publish real-time earthquake information but also display these data and their background geoscience information in a 3D scene. It provides a powerful tool for display, analysis, and decision-making for researchers and administrators. It also facilitates better communication between researchers engaged in geosciences and the interested public.

  11. Data acquisition electronics and reconstruction software for real time 3D track reconstruction within the MIMAC project

    NASA Astrophysics Data System (ADS)

    Bourrion, O.; Bosson, G.; Grignon, C.; Bouly, J. L.; Richer, J. P.; Guillaudin, O.; Mayet, F.; Billard, J.; Santos, D.

    2011-11-01

    Directional detection of non-baryonic Dark Matter requires 3D reconstruction of low energy nuclear recoils tracks. A gaseous micro-TPC matrix, filled with either 3He, CF4 or C4H10 has been developed within the MIMAC project. A dedicated acquisition electronics and a real time track reconstruction software have been developed to monitor a 512 channel prototype. This auto-triggered electronic uses embedded processing to reduce the data transfer to its useful part only, i.e. decoded coordinates of hit tracks and corresponding energy measurements. An acquisition software with on-line monitoring and 3D track reconstruction is also presented.

  12. A Bayesian approach to real-time 3D tumor localization via monoscopic x-ray imaging during treatment delivery

    SciTech Connect

    Li, Ruijiang; Fahimian, Benjamin P.; Xing, Lei

    2011-07-15

    Purpose: Monoscopic x-ray imaging with on-board kV devices is an attractive approach for real-time image guidance in modern radiation therapy such as VMAT or IMRT, but it falls short in providing reliable information along the direction of imaging x-ray. By effectively taking consideration of projection data at prior times and/or angles through a Bayesian formalism, the authors develop an algorithm for real-time and full 3D tumor localization with a single x-ray imager during treatment delivery. Methods: First, a prior probability density function is constructed using the 2D tumor locations on the projection images acquired during patient setup. Whenever an x-ray image is acquired during the treatment delivery, the corresponding 2D tumor location on the imager is used to update the likelihood function. The unresolved third dimension is obtained by maximizing the posterior probability distribution. The algorithm can also be used in a retrospective fashion when all the projection images during the treatment delivery are used for 3D localization purposes. The algorithm does not involve complex optimization of any model parameter and therefore can be used in a ''plug-and-play'' fashion. The authors validated the algorithm using (1) simulated 3D linear and elliptic motion and (2) 3D tumor motion trajectories of a lung and a pancreas patient reproduced by a physical phantom. Continuous kV images were acquired over a full gantry rotation with the Varian TrueBeam on-board imaging system. Three scenarios were considered: fluoroscopic setup, cone beam CT setup, and retrospective analysis. Results: For the simulation study, the RMS 3D localization error is 1.2 and 2.4 mm for the linear and elliptic motions, respectively. For the phantom experiments, the 3D localization error is < 1 mm on average and < 1.5 mm at 95th percentile in the lung and pancreas cases for all three scenarios. The difference in 3D localization error for different scenarios is small and is not

  13. The 2p33s, 3p and 3d configurations of eight times ionized sulphur, S IX

    NASA Astrophysics Data System (ADS)

    Jupén, Christer; Engström, Lars

    1997-12-01

    The spectrum of eight times ionized sulphur, S IX, has been investigated in the wavelength region 690 to 960 Å by means of the beam-foil method. Twenty-three new lines have been identified as combinations between levels of the 2p33s, 3p and 3d configurations. Many of these lines have also recently been found in spectra of the solar corona recorded by the SOHO satellite. We have also identified 12 new lines between 47 and 55 Å as combinations between the 2s22p4 ground configuration and 2p33s and 3d. The new transitions combined with previously known data establish all 10 2p33s levels, 13 of the possible 28 3p levels and 34 out of 38 3d levels. The spectroscopic identifications are supported by isoelectronic extrapolations and by theoretical calculations.

  14. A 3D moisture-stress FEM analysis for time dependent problems in timber structures

    NASA Astrophysics Data System (ADS)

    Fortino, Stefania; Mirianon, Florian; Toratti, Tomi

    2009-11-01

    This paper presents a 3D moisture-stress numerical analysis for timber structures under variable humidity and load conditions. An orthotropic viscoelastic-mechanosorptive material model is specialized on the basis of previous models. Both the constitutive model and the equations needed to describe the moisture flow across the structure are implemented into user subroutines of the Abaqus finite element code and a coupled moisture-stress analysis is performed for several types of mechanical loads and moisture changes. The presented computational approach is validated by analyzing some wood tests described in the literature and comparing the computational results with the reported experimental data.

  15. Time resolved 3D momentum imaging of ultrafast dynamics by coherent VUV-XUV radiation.

    PubMed

    Sturm, F P; Wright, T W; Ray, D; Zalyubovskaya, I; Shivaram, N; Slaughter, D S; Ranitovic, P; Belkacem, A; Weber, Th

    2016-06-01

    We present a new experimental setup for measuring ultrafast nuclear and electron dynamics of molecules after photo-excitation and ionization. We combine a high flux femtosecond vacuum ultraviolet (VUV) and extreme ultraviolet (XUV) source with an internally cold molecular beam and a 3D momentum imaging particle spectrometer to measure electrons and ions in coincidence. We describe a variety of tools developed to perform pump-probe studies in the VUV-XUV spectrum and to modify and characterize the photon beam. First benchmark experiments are presented to demonstrate the capabilities of the system. PMID:27370429

  16. Time resolved 3D momentum imaging of ultrafast dynamics by coherent VUV-XUV radiation

    NASA Astrophysics Data System (ADS)

    Sturm, F. P.; Wright, T. W.; Ray, D.; Zalyubovskaya, I.; Shivaram, N.; Slaughter, D. S.; Ranitovic, P.; Belkacem, A.; Weber, Th.

    2016-06-01

    We present a new experimental setup for measuring ultrafast nuclear and electron dynamics of molecules after photo-excitation and ionization. We combine a high flux femtosecond vacuum ultraviolet (VUV) and extreme ultraviolet (XUV) source with an internally cold molecular beam and a 3D momentum imaging particle spectrometer to measure electrons and ions in coincidence. We describe a variety of tools developed to perform pump-probe studies in the VUV-XUV spectrum and to modify and characterize the photon beam. First benchmark experiments are presented to demonstrate the capabilities of the system.

  17. 3D real-time visualization of blood flow in cerebral aneurysms by light field particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Carlsohn, Matthias F.; Kemmling, André; Petersen, Arne; Wietzke, Lennart

    2016-04-01

    Cerebral aneurysms require endovascular treatment to eliminate potentially lethal hemorrhagic rupture by hemostasis of blood flow within the aneurysm. Devices (e.g. coils and flow diverters) promote homeostasis, however, measurement of blood flow within an aneurysm or cerebral vessel before and after device placement on a microscopic level has not been possible so far. This would allow better individualized treatment planning and improve manufacture design of devices. For experimental analysis, direct measurement of real-time microscopic cerebrovascular flow in micro-structures may be an alternative to computed flow simulations. An application of microscopic aneurysm flow measurement on a regular basis to empirically assess a high number of different anatomic shapes and the corresponding effect of different devices would require a fast and reliable method at low cost with high throughout assessment. Transparent three dimensional 3D models of brain vessels and aneurysms may be used for microscopic flow measurements by particle image velocimetry (PIV), however, up to now the size of structures has set the limits for conventional 3D-imaging camera set-ups. On line flow assessment requires additional computational power to cope with the processing large amounts of data generated by sequences of multi-view stereo images, e.g. generated by a light field camera capturing the 3D information by plenoptic imaging of complex flow processes. Recently, a fast and low cost workflow for producing patient specific three dimensional models of cerebral arteries has been established by stereo-lithographic (SLA) 3D printing. These 3D arterial models are transparent an exhibit a replication precision within a submillimeter range required for accurate flow measurements under physiological conditions. We therefore test the feasibility of microscopic flow measurements by PIV analysis using a plenoptic camera system capturing light field image sequences. Averaging across a sequence of

  18. Leading time domain seismic precursors

    NASA Astrophysics Data System (ADS)

    Boucouvalas, A. C.; Gkasios, M.; Keskebes, A.; Tselikas, N. T.

    2014-08-01

    The problem of predicting the occurrence of earthquakes is threefold. On one hand it is necessary to predict the date and magnitude of an earthquake, and on the other hand the location of the epicenter. In this work after a brief review of the state of earthquake prediction research, we report on a new leading time precursor for determining time onset of earthquake occurrence. We report the linking between earthquakes of the past with those which happen in the future via Fibonacci, Dual and Lucas numbers (FDL) numbers. We demonstrate it here with two example seed earthquakes at least 100 years old. Using this leading indicator method we can predict significant earthquake events >6.5R, with good accuracy approximately +- 1 day somewhere in the world. From a single seed we produce at least 100 trials simultaneously of which 50% are correct to +- 1day. The indicator is based on Fibonacci, Dual and Lucas numbers (FDL). This result hints that the log periodic FDL numbers are at the root of the understanding of the earthquake mechanism. The theory is based on the assumption that each occurred earthquake discontinuity can be thought of as a generating source of FDL time series. (The mechanism could well be linked to planetary orbits). When future dates are derived from clustering and convergence from previous strong earthquake dates at an FDL time distance, then we have a high probability for an earthquake to occur on that date. We set up a real time system which generates FDL time series from each previous significant earthquake (>7R) and we produce a year to year calendar of high probability earthquake dates. We have tested this over a number of years with considerable success. We have applied this technique for strong (>7R) earthquakes across the globe as well as on a restricted region such as the Greek geographic region where the magnitude is small (>4R-6.5R). In both cases the success of the method is impressive. It is our belief that supplementing this method with

  19. Programmable real-time applications with the 3D-Flow for input data rate systems of hundreds of MHz

    SciTech Connect

    Crosetto, D.

    1996-02-01

    The applicability of the 3D-Flow system to different experimental setups for real-time applications in the range of hundreds of nanoseconds is described. The results of the simulation of several real-time applications using the 3D-Flow demonstrate the advantages of a simple architecture that carries out operations in a balanced manner using regular connections and exceptionally few replicated components compared to conventional microprocessors. Diverse applications can be found that will benefit from this approach: High Energy Physics (HEP), which typically requires discerning patterns from thousands of accelerator particle collision signals up to 40 Mhz input data rate; Medical Imaging, that requires interactive tools for studying fast occurring biological processes; processing output from high-rate CCD cameras in commercial applications, such as quality control in manufacturing; data compression; speech and character recognition; automatic automobile guidance, and other applications. The 3D-Flow system was conceived for experiments at the Superconducting Super Collider (SSC). It was adopted by the Gamma Electron and Muon (GEM) experiment that was to be used for particle identification. The target of the 3D-Flow system was real-time pattern recognition at 100 million frames/sec.

  20. Toward real-time endoscopically-guided robotic navigation based on a 3D virtual surgical field model

    NASA Astrophysics Data System (ADS)

    Gong, Yuanzheng; Hu, Danying; Hannaford, Blake; Seibel, Eric J.

    2015-03-01

    The challenge is to accurately guide the surgical tool within the three-dimensional (3D) surgical field for roboticallyassisted operations such as tumor margin removal from a debulked brain tumor cavity. The proposed technique is 3D image-guided surgical navigation based on matching intraoperative video frames to a 3D virtual model of the surgical field. A small laser-scanning endoscopic camera was attached to a mock minimally-invasive surgical tool that was manipulated toward a region of interest (residual tumor) within a phantom of a debulked brain tumor. Video frames from the endoscope provided features that were matched to the 3D virtual model, which were reconstructed earlier by raster scanning over the surgical field. Camera pose (position and orientation) is recovered by implementing a constrained bundle adjustment algorithm. Navigational error during the approach to fluorescence target (residual tumor) is determined by comparing the calculated camera pose to the measured camera pose using a micro-positioning stage. From these preliminary results, computation efficiency of the algorithm in MATLAB code is near real-time (2.5 sec for each estimation of pose), which can be improved by implementation in C++. Error analysis produced 3-mm distance error and 2.5 degree of orientation error on average. The sources of these errors come from 1) inaccuracy of the 3D virtual model, generated on a calibrated RAVEN robotic platform with stereo tracking; 2) inaccuracy of endoscope intrinsic parameters, such as focal length; and 3) any endoscopic image distortion from scanning irregularities. This work demonstrates feasibility of micro-camera 3D guidance of a robotic surgical tool.

  1. Using 3D Glyph Visualization to Explore Real-time Seismic Data on Immersive and High-resolution Display Systems

    NASA Astrophysics Data System (ADS)

    Nayak, A. M.; Lindquist, K.; Kilb, D.; Newman, R.; Vernon, F.; Leigh, J.; Johnson, A.; Renambot, L.

    2003-12-01

    The study of time-dependent, three-dimensional natural phenomena like earthquakes can be enhanced with innovative and pertinent 3D computer graphics. Here we display seismic data as 3D glyphs (graphics primitives or symbols with various geometric and color attributes), allowing us to visualize the measured, time-dependent, 3D wave field from an earthquake recorded by a certain seismic network. In addition to providing a powerful state-of-health diagnostic of the seismic network, the graphical result presents an intuitive understanding of the real-time wave field that is hard to achieve with traditional 2D visualization methods. We have named these 3D icons `seismoglyphs' to suggest visual objects built from three components of ground motion data (north-south, east-west, vertical) recorded by a seismic sensor. A seismoglyph changes color with time, spanning the spectrum, to indicate when the seismic amplitude is largest. The spatial extent of the glyph indicates the polarization of the wave field as it arrives at the recording station. We compose seismoglyphs using the real time ANZA broadband data (http://www.eqinfo.ucsd.edu) to understand the 3D behavior of a seismic wave field in Southern California. Fifteen seismoglyphs are drawn simultaneously with a 3D topography map of Southern California, as real time data is piped into the graphics software using the Antelope system. At each station location, the seismoglyph evolves with time and this graphical display allows a scientist to observe patterns and anomalies in the data. The display also provides visual clues to indicate wave arrivals and ~real-time earthquake detection. Future work will involve adding phase detections, network triggers and near real-time 2D surface shaking estimates. The visuals can be displayed in an immersive environment using the passive stereoscopic Geowall (http://www.geowall.org). The stereographic projection allows for a better understanding of attenuation due to distance and earth

  2. Time domain phase measuring apparatus

    NASA Technical Reports Server (NTRS)

    Reinhardt, V. S. (Inventor)

    1978-01-01

    The phase and/or period stability of a device is determined by connecting the device in one orthogonal arm of a phase detector having a mixer. In the other arm is an adjustable, variable phase shift device. The output of the mixer is fed through an active low pass filter to derive a DC voltage indicative of the phase shift. The variable phase device is adjusted so that the DC voltage will nullify the phase shift of the tested device under normal conditions. The DC voltage level is converted into a time interval indicative of the phase change of the tested device by determining when the level equals the amplitude of a low frequency ramp voltage. The interval between adjacent equality points can be measured or the period between a reference point on the ramp voltage and the quality be measured.

  3. Modeling of 3d Space-time Surface of Potential Fields and Hydrogeologic Modeling of Nuclear Waste Disposal Sites

    NASA Astrophysics Data System (ADS)

    Shestopalov, V.; Bondarenko, Y.; Zayonts, I.; Rudenko, Y.

    Introduction After the Chernobyl Nuclear Power Plant (CNPP) disaster (04.26.1986) a huge amount (over 2000 sq. km) of nuclear wastes appeared within so-called "Cher- nobyl Exclusion Zone" (CEZ). At present there are not enough storage facilities in the Ukraine for safe disposal of nuclear wastes and hazardous chemical wastes. The urgent problem now is safe isolation of these dangerous wastes. According to the developed state program of radioactive waste management, the construction of a na- tional storage facility of nuclear wastes is planned. It is also possible to create regional storage facilities for hazardous chemical wastes. The region of our exploration cov- ers the eastern part of the Korosten Plutone and its slope, reaching the CNPP. 3D Space-Time Surface Imaging of Geophysical Fields. There are only three direct meth- ods of stress field reconstruction in present practice, namely the field investigations based on the large-scale fracturing tests, petrotectonic and optical polarization meth- ods. Unfortunately, all these methods are extremely laborious and need the regular field tests, which is difficult to conduct in the areas of anisotropic rock outcrops. A compilation of magnetic and gravity data covering the CNPP area was carried out as a prelude to an interpretation study. More than thirty map products were generated from magnetic, gravity and geodesy data to prepare the 3D Space-Time Surface Images (3D STSI). Multi-layer topography and geophysic surfaces included: total magnetic intensity, isostatically-corrected Bouguer gravity, aspect and slope, first and second derivatives, vertical and horizontal curvature, histogram characteristics and space cor- relation coefficients between the gradient fields. Many maps shows the first and sec- ond derivatives of the potential fields, with the results of lineament (edge) structure detection superimposed. The lineament or edges of the potential fields are located from maximal gradient in many directions

  4. Time domain reflectometry for SLC BPM system

    NASA Astrophysics Data System (ADS)

    Thompson, D. R.

    1985-03-01

    A maintenance manual for troubleshooting installed SLC Position Monitor stripline assemblies and the associated cabling, using time Domain Reflectometry is presented. Once a technician becomes familiar with this manual's procedures, the Table of Contents can serve as a checklist.

  5. Microscopic type of real-time uniaxial 3D profilometry by polarization camera

    NASA Astrophysics Data System (ADS)

    Shibata, Shuhei; Kobayashi, Fumio; Barada, Daisuke; Otani, Yukitoshi

    2014-07-01

    This paper introduces a novel polarization structured light pattern projector was done by taking into account the unique characteristic of the pixelated camera and a spatial light modulator (SLM) used. Height variations of reflective samples are retrieved by using fringe contrast modulation on an uniaxial configuration. By placing a special retardance pattern on the SLM, the pixelated camera will detect a phase shifted sinusoidal pattern where later its contrast change will be used to retrieve the height information of the sample under study. The presented system takes into account the defocus change obtained by the height variation of the sample by encoding the information on the fringe contrast of the projected structured light pattern by the SLM. The final purpose of this work is to present a single shot 3D profilometry system based in fringe contrast analysis. Experimental results of a moving glass slide are presented.

  6. Space-time evolution of a growth fold (Betic Cordillera, Spain). Evidences from 3D geometrical modelling

    NASA Astrophysics Data System (ADS)

    Martin-Rojas, Ivan; Alfaro, Pedro; Estévez, Antonio

    2014-05-01

    We present a study that encompasses several software tools (iGIS©, ArcGIS©, Autocad©, etc.) and data (geological mapping, high resolution digital topographic data, high resolution aerial photographs, etc.) to create a detailed 3D geometric model of an active fault propagation growth fold. This 3D model clearly shows structural features of the analysed fold, as well as growth relationships and sedimentary patterns. The results obtained permit us to discuss the kinematics and structural evolution of the fold and the fault in time and space. The study fault propagation fold is the Crevillente syncline. This fold represents the northern limit of the Bajo Segura Basin, an intermontane basin in the Eastern Betic Cordillera (SE Spain) developed from upper Miocene on. 3D features of the Crevillente syncline, including growth pattern, indicate that limb rotation and, consequently, fault activity was higher during Messinian than during Tortonian; consequently, fault activity was also higher. From Pliocene on our data point that limb rotation and fault activity steadies or probably decreases. This in time evolution of the Crevillente syncline is not the same all along the structure; actually the 3D geometric model indicates that observed lateral heterogeneity is related to along strike variation of fault displacement.

  7. A time domain technique for mechanism extraction

    NASA Technical Reports Server (NTRS)

    Dominek, Allen K.; Peters, Leon, Jr.; Burnside, Walter D.

    1987-01-01

    The properties of scattered fields from a structure can be better evaluated from the characteristics of the individual scatterers. Decomposition techniques can be classified either as a matrix or an integral formulation. With either formulation, aspect pattern of frequency information of a scattering center can be obtained. Emphasis is placed on an integral (time domain) isolation extraction technique to obtain the frequency characteristics of scattering mechanisms. This technique has its origins in the time domain interpretation of scattered fields.

  8. Esophagogastric Junction pressure morphology: comparison between a station pull-through and real-time 3D-HRM representation

    PubMed Central

    Nicodème, Frédéric; Lin, Zhiyue; Pandolfino, John E.; Kahrilas, Peter J.

    2013-01-01

    BACKGROUND Esophagogastric junction (EGJ) competence is the fundamental defense against reflux making it of great clinical significance. However, characterizing EGJ competence with conventional manometric methodologies has been confounded by its anatomic and physiological complexity. Recent technological advances in miniaturization and electronics have led to the development of a novel device that may overcome these challenges. METHODS Nine volunteer subjects were studied with a novel 3D-HRM device providing 7.5 mm axial and 45° radial pressure resolution within the EGJ. Real-time measurements were made at rest and compared to simulations of a conventional pull-through made with the same device. Moreover, 3D-HRM recordings were analyzed to differentiate contributing pressure signals within the EGJ attributable to lower esophageal sphincter (LES), diaphragm, and vasculature. RESULTS 3D-HRM recordings suggested that sphincter length assessed by a pull-through method greatly exaggerated the estimate of LES length by failing to discriminate among circumferential contractile pressure and asymmetric extrinsic pressure signals attributable to diaphragmatic and vascular structures. Real-time 3D EGJ recordings found that the dominant constituents of EGJ pressure at rest were attributable to the diaphragm. CONCLUSIONS 3D-HRM permits real-time recording of EGJ pressure morphology facilitating analysis of the EGJ constituents responsible for its function as a reflux barrier making it a promising tool in the study of GERD pathophysiology. The enhanced axial and radial recording resolution of the device should facilitate further studies to explore perturbations in the physiological constituents of EGJ pressure in health and disease. PMID:23734788

  9. Crystal Structure of the Mycoplasma arthritidis-Derived Mitogen in Apo Form Reveals a 3D Domain-Swapped Dimer

    SciTech Connect

    Liu, L.; Li, Z; Guo, Y; VanVranken, S; Mourad, W; Li, H

    2010-01-01

    Mycoplasma arthritidis-derived mitogen (MAM) is a superantigen that can activate large fractions of T cells bearing particular V{beta} elements of T cell receptor. Here, we report the crystal structure of a MAM mutant K201A in apo form (unliganded) at 2.8-{angstrom} resolutions. We also partially refined the crystal structures of the MAM wild type and another MAM mutant L50A in apo forms at low resolutions. Unexpectedly, the structures of these apo MAM molecules display a three-dimensional domain-swapped dimer. The entire C-terminal domains of these MAM molecules are involved in the domain swapping. Functional analyses demonstrated that the K201A and L50A mutants do not show altered ability to bind to their host receptors and that they stimulate the activation of T cells as efficiently as does the wild type. Structural comparisons indicated that the 'reconstituted' MAM monomer from the domain-swapped dimer displays large differences at the hinge regions from the MAM{sub wt} molecule in the receptor-bound form. Further comparison indicated that MAM has a flexible N-terminal loop, implying that conformational changes could occur upon receptor binding.

  10. A novel keratan sulphate domain preferentially expressed on the large aggregating proteoglycan from human articular cartilage is recognized by the monoclonal antibody 3D12/H7.

    PubMed Central

    Fischer, D C; Haubeck, H D; Eich, K; Kolbe-Busch, S; Stöcker, G; Stuhlsatz, H W; Greiling, H

    1996-01-01

    Monoclonal antibodies (mAbs) were prepared against aggrecan which has been isolated from human articular cartilage and purified by several chromatographic steps. One of these mAbs, the aggrecan-specific mAb 3D12/H7, was selected for further characterization. The data presented indicate that this mAb recognizes a novel domain of keratan sulphate chains from aggrecan: (1) immunochemical staining of aggrecan is abolished by treatment with keratanase/keratanase II, but not with keratanase or chondroitin sulphate lyase AC/ABC; (2) after chemical deglycosylation of aggrecan no staining of the core-protein was observed; (3) different immunochemical reactivity was observed against keratan sulphates from articular cartilage, intervertebral disc and cornea for the mAbs 3D12/H7 and 5D4. For further characterization of the epitope, reduced and 3H-labelled keratan sulphate chains were prepared. In an IEF-gel-shift assay it was shown that the 3H-labelled oligosaccharides obtained after keratanase digestion of reduced and 3H-labelled keratan sulphate chains were recognized by the mAb 3D12/H7. Thus it can be concluded that the mAb 3D12/H7 recognizes an epitope in the linkage region present in, at least some, keratan sulphate chains of the large aggregating proteoglycan from human articular cartilage. Moreover, this domain seems to be expressed preferentially on those keratan sulphate chains which occur in the chondroitin sulphate-rich region of aggrecan, since the antibody does not recognize the keratan sulphate-rich region obtained after combined chondroitinase AC/ABC and trypsin digestion of aggrecan. PMID:8836155

  11. A novel keratan sulphate domain preferentially expressed on the large aggregating proteoglycan from human articular cartilage is recognized by the monoclonal antibody 3D12/H7.

    PubMed

    Fischer, D C; Haubeck, H D; Eich, K; Kolbe-Busch, S; Stöcker, G; Stuhlsatz, H W; Greiling, H

    1996-09-15

    Monoclonal antibodies (mAbs) were prepared against aggrecan which has been isolated from human articular cartilage and purified by several chromatographic steps. One of these mAbs, the aggrecan-specific mAb 3D12/H7, was selected for further characterization. The data presented indicate that this mAb recognizes a novel domain of keratan sulphate chains from aggrecan: (1) immunochemical staining of aggrecan is abolished by treatment with keratanase/keratanase II, but not with keratanase or chondroitin sulphate lyase AC/ABC; (2) after chemical deglycosylation of aggrecan no staining of the core-protein was observed; (3) different immunochemical reactivity was observed against keratan sulphates from articular cartilage, intervertebral disc and cornea for the mAbs 3D12/H7 and 5D4. For further characterization of the epitope, reduced and 3H-labelled keratan sulphate chains were prepared. In an IEF-gel-shift assay it was shown that the 3H-labelled oligosaccharides obtained after keratanase digestion of reduced and 3H-labelled keratan sulphate chains were recognized by the mAb 3D12/H7. Thus it can be concluded that the mAb 3D12/H7 recognizes an epitope in the linkage region present in, at least some, keratan sulphate chains of the large aggregating proteoglycan from human articular cartilage. Moreover, this domain seems to be expressed preferentially on those keratan sulphate chains which occur in the chondroitin sulphate-rich region of aggrecan, since the antibody does not recognize the keratan sulphate-rich region obtained after combined chondroitinase AC/ABC and trypsin digestion of aggrecan. PMID:8836155

  12. Real-time visual sensing system achieving high-speed 3D particle tracking with nanometer resolution.

    PubMed

    Cheng, Peng; Jhiang, Sissy M; Menq, Chia-Hsiang

    2013-11-01

    This paper presents a real-time visual sensing system, which is created to achieve high-speed three-dimensional (3D) motion tracking of microscopic spherical particles in aqueous solutions with nanometer resolution. The system comprises a complementary metal-oxide-semiconductor (CMOS) camera, a field programmable gate array (FPGA), and real-time image processing programs. The CMOS camera has high photosensitivity and superior SNR. It acquires images of 128×120 pixels at a frame rate of up to 10,000 frames per second (fps) under the white light illumination from a standard 100 W halogen lamp. The real-time image stream is downloaded from the camera directly to the FPGA, wherein a 3D particle-tracking algorithm is implemented to calculate the 3D positions of the target particle in real time. Two important objectives, i.e., real-time estimation of the 3D position matches the maximum frame rate of the camera and the timing of the output data stream of the system is precisely controlled, are achieved. Two sets of experiments were conducted to demonstrate the performance of the system. First, the visual sensing system was used to track the motion of a 2 μm polystyrene bead, whose motion was controlled by a three-axis piezo motion stage. The ability to track long-range motion with nanometer resolution in all three axes is demonstrated. Second, it was used to measure the Brownian motion of the 2 μm polystyrene bead, which was stabilized in aqueous solution by a laser trapping system. PMID:24216655

  13. A spheroid toxicity assay using magnetic 3D bioprinting and real-time mobile device-based imaging.

    PubMed

    Tseng, Hubert; Gage, Jacob A; Shen, Tsaiwei; Haisler, William L; Neeley, Shane K; Shiao, Sue; Chen, Jianbo; Desai, Pujan K; Liao, Angela; Hebel, Chris; Raphael, Robert M; Becker, Jeanne L; Souza, Glauco R

    2015-01-01

    An ongoing challenge in biomedical research is the search for simple, yet robust assays using 3D cell cultures for toxicity screening. This study addresses that challenge with a novel spheroid assay, wherein spheroids, formed by magnetic 3D bioprinting, contract immediately as cells rearrange and compact the spheroid in relation to viability and cytoskeletal organization. Thus, spheroid size can be used as a simple metric for toxicity. The goal of this study was to validate spheroid contraction as a cytotoxic endpoint using 3T3 fibroblasts in response to 5 toxic compounds (all-trans retinoic acid, dexamethasone, doxorubicin, 5'-fluorouracil, forskolin), sodium dodecyl sulfate (+control), and penicillin-G (-control). Real-time imaging was performed with a mobile device to increase throughput and efficiency. All compounds but penicillin-G significantly slowed contraction in a dose-dependent manner (Z' = 0.88). Cells in 3D were more resistant to toxicity than cells in 2D, whose toxicity was measured by the MTT assay. Fluorescent staining and gene expression profiling of spheroids confirmed these findings. The results of this study validate spheroid contraction within this assay as an easy, biologically relevant endpoint for high-throughput compound screening in representative 3D environments. PMID:26365200

  14. Low-cost real-time 3D PC distributed-interactive-simulation (DIS) application for C4I

    NASA Astrophysics Data System (ADS)

    Gonthier, David L.; Veron, Harry

    1998-04-01

    A 3D Distributed Interactive Simulation (DIS) application was developed and demonstrated in a PC environment. The application is capable of running in the stealth mode or as a player which includes battlefield simulations, such as ModSAF. PCs can be clustered together, but not necessarily collocated, to run a simulation or training exercise on their own. A 3D perspective view of the battlefield is displayed that includes terrain, trees, buildings and other objects supported by the DIS application. Screen update rates of 15 to 20 frames per second have been achieved with fully lit and textured scenes thus providing high quality and fast graphics. A complete PC system can be configured for under $2,500. The software runs under Windows95 and WindowsNT. It is written in C++ and uses a commercial API called RenderWare for 3D rendering. The software uses Microsoft Foundation classes and Microsoft DirectPlay for joystick input. The RenderWare libraries enhance the performance through optimization for MMX and the Pentium Pro processor. The RenderWare and the Righteous 3D graphics board from Orchid Technologies with an advertised rendering rate of up to 2 million texture mapped triangles per second. A low-cost PC DIS simulator that can partake in a real-time collaborative simulation with other platforms is thus achieved.

  15. A spheroid toxicity assay using magnetic 3D bioprinting and real-time mobile device-based imaging

    PubMed Central

    Tseng, Hubert; Gage, Jacob A.; Shen, Tsaiwei; Haisler, William L.; Neeley, Shane K.; Shiao, Sue; Chen, Jianbo; Desai, Pujan K.; Liao, Angela; Hebel, Chris; Raphael, Robert M.; Becker, Jeanne L.; Souza, Glauco R.

    2015-01-01

    An ongoing challenge in biomedical research is the search for simple, yet robust assays using 3D cell cultures for toxicity screening. This study addresses that challenge with a novel spheroid assay, wherein spheroids, formed by magnetic 3D bioprinting, contract immediately as cells rearrange and compact the spheroid in relation to viability and cytoskeletal organization. Thus, spheroid size can be used as a simple metric for toxicity. The goal of this study was to validate spheroid contraction as a cytotoxic endpoint using 3T3 fibroblasts in response to 5 toxic compounds (all-trans retinoic acid, dexamethasone, doxorubicin, 5′-fluorouracil, forskolin), sodium dodecyl sulfate (+control), and penicillin-G (−control). Real-time imaging was performed with a mobile device to increase throughput and efficiency. All compounds but penicillin-G significantly slowed contraction in a dose-dependent manner (Z’ = 0.88). Cells in 3D were more resistant to toxicity than cells in 2D, whose toxicity was measured by the MTT assay. Fluorescent staining and gene expression profiling of spheroids confirmed these findings. The results of this study validate spheroid contraction within this assay as an easy, biologically relevant endpoint for high-throughput compound screening in representative 3D environments. PMID:26365200

  16. Real time reconstruction of 3-D electron density distribution over Europe with TaD profiler

    NASA Astrophysics Data System (ADS)

    Kutiev, Ivan; Marinov, Pencho; Belehaki, Anna

    2015-04-01

    TaD (TSM-assisted Digisonde) profiler, developed on the base of Topside Sounder Model (TSM), provides vertical electron density profile (EDP) from the bottom of ionosphere up to the GNSS orbit heights over Digisonde sounding stations. TaD EDP uses the bottomside profile provided by Digisonde software and extends it above the F layer peak by representing O+ distribution by α-Chapman formula and H+ distribution by a single exponent. The profile above F layer peak takes the topside scale height HT and transition height hT from TSM and plasmasphere scale height Hp defined as a function of HT. All these profile parameters are adjusted to the current conditions by comparing the profile integral with measured GNSS TEC. The latter is taken from GNSS TEC maps produced by Royal Observatory of Belgium in the area (35˚, 60˚)N and (-15˚, 25˚)E. Maps of foF2 and hmF2 are produced in the same area on the base of DIAS (European Digital Upper Atmosphere Server) network of Digisonde stations and TaD profiles are calculated at all grid nodes (1˚x1˚) on latitude and longitude. Electron density at any point of the 3-D space is then obtained by simple interpolation between nodes. Possible use of reconstruction technique to GNSS applications is demonstrated by calculating the distribution of electron density along various ray paths of GNSS signals.

  17. Time-domain Raman analytical forward solvers.

    PubMed

    Martelli, Fabrizio; Binzoni, Tiziano; Sekar, Sanathana Konugolu Venkata; Farina, Andrea; Cavalieri, Stefano; Pifferi, Antonio

    2016-09-01

    A set of time-domain analytical forward solvers for Raman signals detected from homogeneous diffusive media is presented. The time-domain solvers have been developed for two geometries: the parallelepiped and the finite cylinder. The potential presence of a background fluorescence emission, contaminating the Raman signal, has also been taken into account. All the solvers have been obtained as solutions of the time dependent diffusion equation. The validation of the solvers has been performed by means of comparisons with the results of "gold standard" Monte Carlo simulations. These forward solvers provide an accurate tool to explore the information content encoded in the time-resolved Raman measurements. PMID:27607645

  18. First MMS Observations of High Time Resolution 3D Electric and Magnetic fields at the Dayside Magnetopause.

    NASA Astrophysics Data System (ADS)

    Torbert, R. B.; Burch, J. L.; Russell, C. T.; Magnes, W.; Ergun, R. E.; Lindqvist, P. A.; Le Contel, O.; Vaith, H.; Macri, J.; Myers, S.; Rau, D.; Needell, J.; King, B.; Granoff, M.; Chutter, M.; Dors, I.; Argall, M. R.; Shuster, J. R.; Olsson, G.; Marklund, G. T.; Khotyaintsev, Y. V.; Eriksson, A. I.; Kletzing, C.; Bounds, S. R.; Anderson, B. J.; Baumjohann, W.; Steller, M.; Bromund, K. R.; Le, G.; Nakamura, R.; Strangeway, R. J.; Leinweber, H. K.; Tucker, S.; Westfall, J.; Fischer, D.; Plaschke, F.; Pollock, C. J.; Giles, B. L.; Moore, T. E.; Mauk, B.; Fuselier, S. A.

    2015-12-01

    The electrodynamics at the magnetopause is key to our understanding of ion and electron acceleration within reconnection regions. The Magnetospheric Multiscale (MMS) fleet of four spacecraft was launched into its Phase-1 equatorial orbit of 12 Re apogee specifically to investigate these regions at the Earth's magnetopause. In addition to a comprehensive suite of particle measurements, MMS makes very high time resolution 3D electric and magnetic field measurements of high accuracy using flux-gate, search coil, 3-axis double probe, and electron drift sensors. In September 2015, the MMS fleet will begin to encounter the dusk-side magnetopause in its initial configuration of approximately 160 km separation, allowing investigation of the spatial and temporal characteristics of important electrodynamics during reconnection. Using these field and particle measurements, we present first observations of 3D magnetic and electric fields (including their parallel component), and inferred current sheets, during active magnetopause crossings using the highest time resolution data available on MMS.

  19. Cardiac C-arm computed tomography using a 3D + time ROI reconstruction method with spatial and temporal regularization

    SciTech Connect

    Mory, Cyril; Auvray, Vincent; Zhang, Bo; Grass, Michael; Schäfer, Dirk; Chen, S. James; Carroll, John D.; Rit, Simon; Peyrin, Françoise; Douek, Philippe; Boussel, Loïc

    2014-02-15

    Purpose: Reconstruction of the beating heart in 3D + time in the catheter laboratory using only the available C-arm system would improve diagnosis, guidance, device sizing, and outcome control for intracardiac interventions, e.g., electrophysiology, valvular disease treatment, structural or congenital heart disease. To obtain such a reconstruction, the patient's electrocardiogram (ECG) must be recorded during the acquisition and used in the reconstruction. In this paper, the authors present a 4D reconstruction method aiming to reconstruct the heart from a single sweep 10 s acquisition. Methods: The authors introduce the 4D RecOnstructiOn using Spatial and TEmporal Regularization (short 4D ROOSTER) method, which reconstructs all cardiac phases at once, as a 3D + time volume. The algorithm alternates between a reconstruction step based on conjugate gradient and four regularization steps: enforcing positivity, averaging along time outside a motion mask that contains the heart and vessels, 3D spatial total variation minimization, and 1D temporal total variation minimization. Results: 4D ROOSTER recovers the different temporal representations of a moving Shepp and Logan phantom, and outperforms both ECG-gated simultaneous algebraic reconstruction technique and prior image constrained compressed sensing on a clinical case. It generates 3D + time reconstructions with sharp edges which can be used, for example, to estimate the patient's left ventricular ejection fraction. Conclusions: 4D ROOSTER can be applied for human cardiac C-arm CT, and potentially in other dynamic tomography areas. It can easily be adapted to other problems as regularization is decoupled from projection and back projection.

  20. Optimal transcostal high-intensity focused ultrasound with combined real-time 3D movement tracking and correction

    NASA Astrophysics Data System (ADS)

    Marquet, F.; Aubry, J. F.; Pernot, M.; Fink, M.; Tanter, M.

    2011-11-01

    Recent studies have demonstrated the feasibility of transcostal high intensity focused ultrasound (HIFU) treatment in liver. However, two factors limit thermal necrosis of the liver through the ribs: the energy deposition at focus is decreased by the respiratory movement of the liver and the energy deposition on the skin is increased by the presence of highly absorbing bone structures. Ex vivo ablations were conducted to validate the feasibility of a transcostal real-time 3D movement tracking and correction mode. Experiments were conducted through a chest phantom made of three human ribs immersed in water and were placed in front of a 300 element array working at 1 MHz. A binarized apodization law introduced recently in order to spare the rib cage during treatment has been extended here with real-time electronic steering of the beam. Thermal simulations have been conducted to determine the steering limits. In vivo 3D-movement detection was performed on pigs using an ultrasonic sequence. The maximum error on the transcostal motion detection was measured to be 0.09 ± 0.097 mm on the anterior-posterior axis. Finally, a complete sequence was developed combining real-time 3D transcostal movement correction and spiral trajectory of the HIFU beam, allowing the system to treat larger areas with optimized efficiency. Lesions as large as 1 cm in diameter have been produced at focus in excised liver, whereas no necroses could be obtained with the same emitted power without correcting the movement of the tissue sample.

  1. Casimir forces in the time domain: Theory

    SciTech Connect

    Rodriguez, Alejandro W.; McCauley, Alexander P.; Joannopoulos, John D.; Johnson, Steven G.

    2009-07-15

    We present a method to compute Casimir forces in arbitrary geometries and for arbitrary materials based on the finite-difference time-domain (FDTD) scheme. The method involves the time evolution of electric and magnetic fields in response to a set of current sources, in a modified medium with frequency-independent conductivity. The advantage of this approach is that it allows one to exploit existing FDTD software, without modification, to compute Casimir forces. In this paper, we focus on the derivation, implementation choices, and essential properties of the time-domain algorithm, both considered analytically and illustrated in the simplest parallel-plate geometry.

  2. Time Efficient 3D Radial UTE Sampling with Fully Automatic Delay Compensation on a Clinical 3T MR Scanner

    PubMed Central

    Reichenbach, Jürgen R.

    2016-01-01

    This work’s aim was to minimize the acquisition time of a radial 3D ultra-short echo-time (UTE) sequence and to provide fully automated, gradient delay compensated, and therefore artifact free, reconstruction. The radial 3D UTE sequence (echo time 60 μs) was implemented as single echo acquisition with center-out readouts and improved time efficient spoiling on a clinical 3T scanner without hardware modifications. To assess the sequence parameter dependent gradient delays each acquisition contained a quick calibration scan and utilized the phase of the readouts to detect the actual k-space center. This calibration scan does not require any user interaction. To evaluate the robustness of this automatic delay estimation phantom experiments were performed and 19 in vivo imaging data of the head, tibial cortical bone, feet and lung were acquired from 6 volunteers. As clinical application of this fast 3D UTE acquisition single breath-hold lung imaging is demonstrated. The proposed sequence allowed very short repetition times (TR~1ms), thus reducing total acquisition time. The proposed, fully automated k-phase based gradient delay calibration resulted in accurate delay estimations (difference to manually determined optimal delay −0.13 ± 0.45 μs) and allowed unsupervised reconstruction of high quality images for both phantom and in vivo data. The employed fast spoiling scheme efficiently suppressed artifacts caused by incorrectly refocused echoes. The sequence proved to be quite insensitive to motion, flow and susceptibility artifacts and provides oversampling protection against aliasing foldovers in all directions. Due to the short TR, acquisition times are attractive for a wide range of clinical applications. For short T2* mapping this sequence provides free choice of the second TE, usually within less scan time as a comparable dual echo UTE sequence. PMID:26975051

  3. Time Efficient 3D Radial UTE Sampling with Fully Automatic Delay Compensation on a Clinical 3T MR Scanner.

    PubMed

    Herrmann, Karl-Heinz; Krämer, Martin; Reichenbach, Jürgen R

    2016-01-01

    This work's aim was to minimize the acquisition time of a radial 3D ultra-short echo-time (UTE) sequence and to provide fully automated, gradient delay compensated, and therefore artifact free, reconstruction. The radial 3D UTE sequence (echo time 60 μs) was implemented as single echo acquisition with center-out readouts and improved time efficient spoiling on a clinical 3T scanner without hardware modifications. To assess the sequence parameter dependent gradient delays each acquisition contained a quick calibration scan and utilized the phase of the readouts to detect the actual k-space center. This calibration scan does not require any user interaction. To evaluate the robustness of this automatic delay estimation phantom experiments were performed and 19 in vivo imaging data of the head, tibial cortical bone, feet and lung were acquired from 6 volunteers. As clinical application of this fast 3D UTE acquisition single breath-hold lung imaging is demonstrated. The proposed sequence allowed very short repetition times (TR~1ms), thus reducing total acquisition time. The proposed, fully automated k-phase based gradient delay calibration resulted in accurate delay estimations (difference to manually determined optimal delay -0.13 ± 0.45 μs) and allowed unsupervised reconstruction of high quality images for both phantom and in vivo data. The employed fast spoiling scheme efficiently suppressed artifacts caused by incorrectly refocused echoes. The sequence proved to be quite insensitive to motion, flow and susceptibility artifacts and provides oversampling protection against aliasing foldovers in all directions. Due to the short TR, acquisition times are attractive for a wide range of clinical applications. For short T2* mapping this sequence provides free choice of the second TE, usually within less scan time as a comparable dual echo UTE sequence. PMID:26975051

  4. Optical identification based on time domain optical coherence tomography.

    PubMed

    Gandhi, Vishal; Semenov, Dmitry; Honkanen, Seppo; Hauta-Kasari, Markku

    2015-09-01

    We present a novel method for optical identification, i.e., authenticating valuable documents such as a passport, credit cards, and bank notes, using optical coherence tomography (OCT). An OCT system can capture three-dimensional (3D) images and visualize the internal structure of an object. In our work, as an object, we consider a multilayered optical identification tag composed of a limited number of thin layers (10-100 μm thick). The thickness, width, and location of the layers in the tag encode a unique identification information. Reading of the tag is done using a time domain OCT (TD-OCT) system. Typically, a TD-OCT system requires continuous mechanical scanning in one or more directions to get a 3D volume image of an object. The continuous scanning implies a complicated optical setup, which makes an OCT system fragile and expensive. We propose to avoid the conventional scanning by (1) not requiring 3D imaging, and (2) utilizing the motion of the optical tag itself. The motion is introduced to the tag reader, for example, by a user, which replaces the need for conventional scanning. The absence of a conventional scanning mechanism makes the proposed OCT method very simple and suited for identification purposes; however, it also puts some constraints to the construction of the optical tag, which we discuss in this paper in detail. PMID:26368871

  5. CO2 mass estimation visible in time-lapse 3D seismic data from a saline aquifer and uncertainties

    NASA Astrophysics Data System (ADS)

    Ivanova, A.; Lueth, S.; Bergmann, P.; Ivandic, M.

    2014-12-01

    At Ketzin (Germany) the first European onshore pilot scale project for geological storage of CO2 was initiated in 2004. This project is multidisciplinary and includes 3D time-lapse seismic monitoring. A 3D pre-injection seismic survey was acquired in 2005. Then CO2 injection into a sandstone saline aquifer started at a depth of 650 m in 2008. A 1st 3D seismic repeat survey was acquired in 2009 after 22 kilotons had been injected. The imaged CO2 signature was concentrated around the injection well (200-300 m). A 2nd 3D seismic repeat survey was acquired in 2012 after 61 kilotons had been injected. The imaged CO2 signature further extended (100-200 m). The injection was terminated in 2013. Totally 67 kilotons of CO2 were injected. Time-lapse seismic processing, petrophysical data and geophysical logging on CO2 saturation have allowed for an estimate of the amount of CO2 visible in the seismic data. This estimate is dependent upon a choice of a number of parameters and contains a number of uncertainties. The main uncertainties are following. The constant reservoir porosity and CO2 density used for the estimation are probably an over-simplification since the reservoir is quite heterogeneous. May be velocity dispersion is present in the Ketzin reservoir rocks, but we do not consider it to be large enough that it could affect the mass of CO2 in our estimation. There are only a small number of direct petrophysical observations, providing a weak statistical basis for the determination of seismic velocities based on CO2 saturation and we have assumed that the petrophysical experiments were carried out on samples that are representative for the average properties of the whole reservoir. Finally, the most of the time delay values in the both 3D seismic repeat surveys within the amplitude anomaly are near the noise level of 1-2 ms, however a change of 1 ms in the time delay affects significantly the mass estimate, thus the choice of the time-delay cutoff is crucial. In spite

  6. Evaluation of natural and nitramine binding energies to 3-D models of the S1S2 domains in the N-methyl-D-aspartate receptor.

    PubMed

    Ford-Green, Jason; Isayev, Olexandr; Gorb, Leonid; Perkins, Edward J; Leszczynski, Jerzy

    2012-04-01

    Overactivation of the N-methyl-D-aspartate receptor (NMDAR) in postsynaptic neurons leads to glutamate-related excitotoxicity in the central nervous system of mammals. We have built 3-D models of each domain for the universal screening of potential toxicants and their binding mechanisms. Our docking results show that the calculated pK (i) values of glycine and L: -glutamate significantly increase (>1) when the NR1 and NR2A S1S2 domains are closing, respectively. Inversely, D: -cycloserine (DCS) and 5,7-dichlorokynurenic acid (5,7-DCKA) do not show such a dependence on domain closure. Replica exchange molecular dynamics (REMD) confirmed 5 different conformational states of the S1S2 domain along the 308.2 K temperature trajectory. Analysis of residue fluctuations during this temperature trajectory showed that residues in loop 1, loop 2, the amino terminal domain (ATD), and the area linked to ion channel α-helices are involved in this movement. This further implicates the notion that efficacious ligands act through S1S2 lobe movement which can culminate in the opening or closing of the ion channel. We further tested this by docking hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) to the S1S2 domain. Our results predict that these nitramines are not efficacious and thus do not produce excitoxicity when they bind to the S1S2 domain of the NMDAR. PMID:21735122

  7. Towards real-time 2D/3D registration for organ motion monitoring in image-guided radiation therapy

    NASA Astrophysics Data System (ADS)

    Gendrin, C.; Spoerk, J.; Bloch, C.; Pawiro, S. A.; Weber, C.; Figl, M.; Markelj, P.; Pernus, F.; Georg, D.; Bergmann, H.; Birkfellner, W.

    2010-02-01

    Nowadays, radiation therapy systems incorporate kV imaging units which allow for the real-time acquisition of intra-fractional X-ray images of the patient with high details and contrast. An application of this technology is tumor motion monitoring during irradiation. For tumor tracking, implanted markers or position sensors are used which requires an intervention. 2D/3D intensity based registration is an alternative, non-invasive method but the procedure must be accelerate to the update rate of the device, which lies in the range of 5 Hz. In this paper we investigate fast CT to a single kV X-ray 2D/3D image registration using a new porcine reference phantom with seven implanted fiducial markers. Several parameters influencing the speed and accuracy of the registrations are investigated. First, four intensity based merit functions, namely Cross-Correlation, Rank Correlation, Mutual Information and Correlation Ratio, are compared. Secondly, wobbled splatting and ray casting rendering techniques are implemented on the GPU and the influence of each algorithm on the performance of 2D/3D registration is evaluated. Rendering times for a single DRR of 20 ms were achieved. Different thresholds of the CT volume were also examined for rendering to find the setting that achieves the best possible correspondence with the X-ray images. Fast registrations below 4 s became possible with an inplane accuracy down to 0.8 mm.

  8. Development of real-time motion capture system for 3D on-line games linked with virtual character

    NASA Astrophysics Data System (ADS)

    Kim, Jong Hyeong; Ryu, Young Kee; Cho, Hyung Suck

    2004-10-01

    Motion tracking method is being issued as essential part of the entertainment, medical, sports, education and industry with the development of 3-D virtual reality. Virtual human character in the digital animation and game application has been controlled by interfacing devices; mouse, joysticks, midi-slider, and so on. Those devices could not enable virtual human character to move smoothly and naturally. Furthermore, high-end human motion capture systems in commercial market are expensive and complicated. In this paper, we proposed a practical and fast motion capturing system consisting of optic sensors, and linked the data with 3-D game character with real time. The prototype experiment setup is successfully applied to a boxing game which requires very fast movement of human character.

  9. Single-photon pulsed-light indirect time-of-flight 3D ranging.

    PubMed

    Bellisai, S; Bronzi, D; Villa, F A; Tisa, S; Tosi, A; Zappa, F

    2013-02-25

    "Indirect" time-of-flight is one technique to obtain depth-resolved images through active illumination that is becoming more popular in the recent years. Several methods and light timing patterns are used nowadays, aimed at improving measurement precision with smarter algorithms, while using less and less light power. Purpose of this work is to present an indirect time-of-flight imaging camera based on pulsed-light active illumination and a 32 × 32 single-photon avalanche diode array with an improved illumination timing pattern, able to increase depth resolution and to reach single-photon level sensitivity. PMID:23482043

  10. Lanthanum halide scintillators for time-of-flight 3-D pet

    DOEpatents

    Karp, Joel S.; Surti, Suleman

    2008-06-03

    A Lanthanum Halide scintillator (for example LaCl.sub.3 and LaBr.sub.3) with fast decay time and good timing resolution, as well as high light output and good energy resolution, is used in the design of a PET scanner. The PET scanner includes a cavity for accepting a patient and a plurality of PET detector modules arranged in an approximately cylindrical configuration about the cavity. Each PET detector includes a Lanthanum Halide scintillator having a plurality of Lanthanum Halide crystals, a light guide, and a plurality of photomultiplier tubes arranged respectively peripherally around the cavity. The good timing resolution enables a time-of-flight (TOF) PET scanner to be developed that exhibits a reduction in noise propagation during image reconstruction and a gain in the signal-to-noise ratio. Such a PET scanner includes a time stamp circuit that records the time of receipt of gamma rays by respective PET detectors and provides timing data outputs that are provided to a processor that, in turn, calculates time-of-flight (TOF) of gamma rays through a patient in the cavity and uses the TOF of gamma rays in the reconstruction of images of the patient.

  11. 3D and Education

    NASA Astrophysics Data System (ADS)

    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?

  12. Quantification of fluorescent spots in time series of 3D confocal microscopy images of endoplasmic reticulum exit sites based on the HMAX transform

    NASA Astrophysics Data System (ADS)

    Matula, Petr; Verissimo, Fatima; Wörz, Stefan; Eils, Roland; Pepperkok, Rainer; Rohr, Karl

    2010-03-01

    We present an approach for the quantification of fluorescent spots in time series of 3-D confocal microscopy images of endoplasmic reticulum exit sites of dividing cells. Fluorescent spots are detected based on extracted image regions of highest response using the HMAX transform and prior convolution of the 3-D images with a Gaussian kernel. The sensitivity of the involved parameters was studied and a quantitative evaluation using both 3-D synthetic and 3-D real data was performed. The approach was successfully applied to more than one thousand 3-D confocal microscopy images.

  13. Real-time geometric scene estimation for RGBD images using a 3D box shape grammar

    NASA Astrophysics Data System (ADS)

    Willis, Andrew R.; Brink, Kevin M.

    2016-06-01

    This article describes a novel real-time algorithm for the purpose of extracting box-like structures from RGBD image data. In contrast to conventional approaches, the proposed algorithm includes two novel attributes: (1) it divides the geometric estimation procedure into subroutines having atomic incremental computational costs, and (2) it uses a generative "Block World" perceptual model that infers both concave and convex box elements from detection of primitive box substructures. The end result is an efficient geometry processing engine suitable for use in real-time embedded systems such as those on an UAVs where it is intended to be an integral component for robotic navigation and mapping applications.

  14. Time-resolved diffusion tomographic 2D and 3D imaging in highly scattering turbid media

    NASA Technical Reports Server (NTRS)

    Alfano, Robert R. (Inventor); Cai, Wei (Inventor); Gayen, Swapan K. (Inventor)

    2000-01-01

    A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine: .LAMBDA..sub.ij =.lambda..sub.j .delta..sub.ij with .lambda..sub.j =/<.DELTA.Xj.DELTA.Xj> Y is the data collected at the detectors, and X.sup.k is the kth iterate toward the desired absorption information. An algorithm, which combines a two dimensional (2D) matrix inversion with a one-dimensional (1D) Fourier transform inversion is used to obtain images of three dimensional hidden objects in turbid scattering media.

  15. Time-resolved diffusion tomographic 2D and 3D imaging in highly scattering turbid media

    NASA Technical Reports Server (NTRS)

    Alfano, Robert R. (Inventor); Cai, Wei (Inventor); Liu, Feng (Inventor); Lax, Melvin (Inventor); Das, Bidyut B. (Inventor)

    1999-01-01

    A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: ##EQU1## wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine: .LAMBDA..sub.ij =.lambda..sub.j .delta..sub.ij with .lambda..sub.j =/<.DELTA.Xj.DELTA.Xj> Y is the data collected at the detectors, and X.sup.k is the kth iterate toward the desired absoption information. An algorithm, which combines a two dimensional (2D) matrix inversion with a one-dimensional (1D) Fourier transform inversion is used to obtain images of three dimensional hidden objects in turbid scattering media.

  16. Research on transformation and optimization of large scale 3D modeling for real time rendering

    NASA Astrophysics Data System (ADS)

    Yan, Hu; Yang, Yongchao; Zhao, Gang; He, Bin; Shen, Guosheng

    2011-12-01

    During the simulation process of real-time three-dimensional scene, the popular modeling software and the real-time rendering platform are not compatible. The common solution is to create three-dimensional scene model by using modeling software and then transform the format supported by rendering platform. This paper takes digital campus scene simulation as an example, analyzes and solves the problems of surface loss; texture distortion and loss; model flicker and so on during the transformation from 3Ds Max to MultiGen Creator. Besides, it proposes the optimization strategy of model which is transformed. The operation results show that this strategy is a good solution to all kinds of problems existing in transformation and it can speed up the rendering speed of the model.

  17. Real-time 3D imaging of Haines jumps in porous media flow

    PubMed Central

    Berg, Steffen; Ott, Holger; Klapp, Stephan A.; Schwing, Alex; Neiteler, Rob; Brussee, Niels; Makurat, Axel; Leu, Leon; Enzmann, Frieder; Schwarz, Jens-Oliver; Kersten, Michael; Irvine, Sarah; Stampanoni, Marco

    2013-01-01

    Newly developed high-speed, synchrotron-based X-ray computed microtomography enabled us to directly image pore-scale displacement events in porous rock in real time. Common approaches to modeling macroscopic fluid behavior are phenomenological, have many shortcomings, and lack consistent links to elementary pore-scale displacement processes, such as Haines jumps and snap-off. Unlike the common singular pore jump paradigm based on observations of restricted artificial capillaries, we found that Haines jumps typically cascade through 10–20 geometrically defined pores per event, accounting for 64% of the energy dissipation. Real-time imaging provided a more detailed fundamental understanding of the elementary processes in porous media, such as hysteresis, snap-off, and nonwetting phase entrapment, and it opens the way for a rigorous process for upscaling based on thermodynamic models. PMID:23431151

  18. The 2-D and 3-D time marching transonic potential flow method for propfans

    NASA Technical Reports Server (NTRS)

    Williams, Marc H.

    1988-01-01

    Recent efforts concentrated on the development of aerodynamic tools for the analysis of rotors at transonic speeds and of configurations involving relative rotation. Three distinct approaches were taken: (1) extension of the lifting surface method of Williams and Hwang (1986) to relative rotation; (2) development of a time marching linear potential method for counter rotation; and (3) development of 2 and 3 dimensional finite volume potential flow schemes for single rotation. Results from each of these approaches are described.

  19. Enhanced imaging of CO2 at the Ketzin storage site: Inversion of 3D time-lapse seismic data

    NASA Astrophysics Data System (ADS)

    Gil, M.; Götz, J.; Ivanova, A.; Juhlin, C.; Krawczyk, C. M.; Lüth, S.; Yang, C.

    2012-04-01

    The Ketzin test site, located near Berlin, is Europe's longest-operating on-shore CO2 storage site. As of December 2011, more than 56,000 tons of food grade CO2 has been injected since June 2008 in an anticlinal structure of the Northeast German Basin. The target reservoir consists of porous, brine bearing sandstone units of the Upper Triassic Stuttgart Formation at approximately 630 to 650 m depth. In order to enhance the understanding of the structural geometry of the site and to investigate the extension of the CO2-plume, several geophysical monitoring methods are being applied at Ketzin, among these are active seismic measurements, geoelectrics and borehole measurements. Among the various seismic techniques (e.g. 2D reflection surveys, crosshole tomography, Vertical Seismic Profiling, 2D- and 3D-Moving Source Profiling) employed at this pilot site, 3D time-lapse reflection surveys are an important component. The baseline 3D survey was acquired in 2005 and the first repeat measurements were performed in 2009 after injection of about 22,000 tons of CO2. The second repeat survey is planned to be carried out in fall 2012. These measurements allow the time-lapse signature of the injected CO2 to be imaged. The time-lapse amplitude variation attributed to the injected CO2 in the reservoir matches, considering detection limits of seismic surface measurements, the expected distribution of the CO2 plume derived from reservoir simulations. Previous attempts towards a quantitative interpretation were based on integrative considerations of different types of geophysical measurements using strict assumptions and characterized by large error bars. In order to increase the resolution and reliability of the data and to improve estimation of rock properties and especially to enhance the imaging resolution of the CO2-plume, the time-lapse 3D seismic data have now been inverted for seismic impedances with different methods, which is the focus of this presentation. One difficulty

  20. Detection and Alignment of 3D Domain Swapping Proteins Using Angle-Distance Image-Based Secondary Structural Matching Techniques

    PubMed Central

    Wang, Hsin-Wei; Hsu, Yen-Chu; Hwang, Jenn-Kang; Lyu, Ping-Chiang; Pai, Tun-Wen; Tang, Chuan Yi

    2010-01-01

    This work presents a novel detection method for three-dimensional domain swapping (DS), a mechanism for forming protein quaternary structures that can be visualized as if monomers had “opened” their “closed” structures and exchanged the opened portion to form intertwined oligomers. Since the first report of DS in the mid 1990s, an increasing number of identified cases has led to the postulation that DS might occur in a protein with an unconstrained terminus under appropriate conditions. DS may play important roles in the molecular evolution and functional regulation of proteins and the formation of depositions in Alzheimer's and prion diseases. Moreover, it is promising for designing auto-assembling biomaterials. Despite the increasing interest in DS, related bioinformatics methods are rarely available. Owing to a dramatic conformational difference between the monomeric/closed and oligomeric/open forms, conventional structural comparison methods are inadequate for detecting DS. Hence, there is also a lack of comprehensive datasets for studying DS. Based on angle-distance (A-D) image transformations of secondary structural elements (SSEs), specific patterns within A-D images can be recognized and classified for structural similarities. In this work, a matching algorithm to extract corresponding SSE pairs from A-D images and a novel DS score have been designed and demonstrated to be applicable to the detection of DS relationships. The Matthews correlation coefficient (MCC) and sensitivity of the proposed DS-detecting method were higher than 0.81 even when the sequence identities of the proteins examined were lower than 10%. On average, the alignment percentage and root-mean-square distance (RMSD) computed by the proposed method were 90% and 1.8Å for a set of 1,211 DS-related pairs of proteins. The performances of structural alignments remain high and stable for DS-related homologs with less than 10% sequence identities. In addition, the quality of its hinge

  1. An eliminating method of motion-induced vertical parallax for time-division 3D display technology

    NASA Astrophysics Data System (ADS)

    Lin, Liyuan; Hou, Chunping

    2015-10-01

    A time difference between the left image and right image of the time-division 3D display makes a person perceive alternating vertical parallax when an object is moving vertically on a fixed depth plane, which causes the left image and right image perceived do not match and makes people more prone to visual fatigue. This mismatch cannot eliminate simply rely on the precise synchronous control of the left image and right image. Based on the principle of time-division 3D display technology and human visual system characteristics, this paper establishes a model of the true vertical motion velocity in reality and vertical motion velocity on the screen, and calculates the amount of the vertical parallax caused by vertical motion, and then puts forward a motion compensation method to eliminate the vertical parallax. Finally, subjective experiments are carried out to analyze how the time difference affects the stereo visual comfort by comparing the comfort values of the stereo image sequences before and after compensating using the eliminating method. The theoretical analysis and experimental results show that the proposed method is reasonable and efficient.

  2. In vitro 3-D model based on extending time of culture for studying chronological epidermis aging.

    PubMed

    Dos Santos, Morgan; Metral, Elodie; Boher, Aurélie; Rousselle, Patricia; Thepot, Amélie; Damour, Odile

    2015-09-01

    Skin aging is a complex phenomenon in which several mechanisms operate simultaneously. Among them, intrinsic aging is a time-dependent process, which leads to gradual skin changes affecting its structure and function such as thinning down of both epidermal and dermal compartments and a flattening and fragility of the dermo-epidermal junction. Today, several approaches have been proposed for the generation of aged skin in vitro, including skin explants from aged donors and three-dimensional skin equivalent treated by aging-inducing chemical compounds or engineered with human cells isolated from aged donors. The aim of this study was to develop and validate a new in vitro model of aging based on skin equivalent demonstrating the same phenotypic changes that were observed in chronological aging. By using prolonged culture as a proxy for cellular aging, we extended to 120 days the culture time of a skin equivalent model based on collagen-glycosaminoglycan-chitosan porous polymer and engineered with human skin cells from photo-protected sites of young donors. Morphological, immunohistological and ultrastructural analysis at different time points of the culture allowed characterizing the phenotypic changes observed in our model in comparison to samples of non photo-exposed normal human skin from different ages. We firstly confirmed that long-term cultured skin equivalents are still morphologically consistent and functionally active even after 120 days of culture. However, similar to in vivo chronological skin aging a significant decrease of the epidermis thickness as well as the number of keratinocyte expressing proliferation marker Ki67 are observed in extended culture time skin equivalent. Epidermal differentiation markers loricrin, filaggrin, involucrin and transglutaminase, also strongly decreased. Ultrastructural analysis of basement membrane showed typical features of aged skin such as duplication of lamina densa and alterations of hemidesmosomes. Moreover, the

  3. Codif: A 3-d Plasma Analyzer With Time-of-flight Mass Discrimination

    NASA Astrophysics Data System (ADS)

    Klecker, B.; Möbius, E.; Kistler, L. M.; Popecki, M. A.; Sauvaud, J.-A.; Reme, H.; Korth, A.; McFadden, J. P.; McCarthy, M. P.; Balsiger, H.

    The development of CODIF (COmposition and DIstribution Function Analyzer) for the CLUSTER mission started in 1988, shortly after the pioneering application of the secondary-electron-emission time-of-flight technique on several missions, includ- ing AMPTE and Giotto. CODIF consists of a toroidal top-hat electrostatic analyzer (ESA), subdivided into 2 halves with geometric factors different by a factor of 100 to cope with the large dynamic range of ion fluxes in the Earth's magnetosphere. Post acceleration of the incoming ions by up to 20 kV, and a time-of-flight mass spectro- graph provide velocity measurements from eV (spacecraft potential) to 40 keV/e and, together with the E/q measurement of the ESA system, a resolution sufficient to sep- arate the most abundant ions H+, He2+, He+, and O+ by onboard analysis. Similar versions of CODIF have now been successfully flown onboard FAST, Equator-S, and CLUSTER-II. The CODIF sensor concept presently serves also as the basis for a new development for the Plasma and Suprathermal Ion Composition (PLASTIC) sensor onboard STEREO. We will discuss the in-flight performance of the CODIF sensor using recent measurements in various regions of the Earth's magnetosphere.

  4. Real-time 3-D SAFT-UT system evaluation and validation

    SciTech Connect

    Doctor, S.R.; Schuster, G.J.; Reid, L.D.; Hall, T.E.

    1996-09-01

    SAFT-UT technology is shown to provide significant enhancements to the inspection of materials used in US nuclear power plants. This report provides guidelines for the implementation of SAFT-UT technology and shows the results from its application. An overview of the development of SAFT-UT is provided so that the reader may become familiar with the technology. Then the basic fundamentals are presented with an extensive list of references. A comprehensive operating procedure, which is used in conjunction with the SAFT-UT field system developed by Pacific Northwest Laboratory (PNL), provides the recipe for both SAFT data acquisition and analysis. The specification for the hardware implementation is provided for the SAFT-UT system along with a description of the subsequent developments and improvements. One development of technical interest is the SAFT real time processor. Performance of the real-time processor is impressive and comparison is made of this dedicated parallel processor to a conventional computer and to the newer high-speed computer architectures designed for image processing. Descriptions of other improvements, including a robotic scanner, are provided. Laboratory parametric and application studies, performed by PNL and not previously reported, are discussed followed by a section on field application work in which SAFT was used during inservice inspections of operating reactors.

  5. Real-time estimation of FLE statistics for 3-D tracking with point-based registration.

    PubMed

    Wiles, Andrew D; Peters, Terry M

    2009-09-01

    Target registration error (TRE) has become a widely accepted error metric in point-based registration since the error metric was introduced in the 1990s. It is particularly prominent in image-guided surgery (IGS) applications where point-based registration is used in both image registration and optical tracking. In point-based registration, the TRE is a function of the fiducial marker geometry, location of the target and the fiducial localizer error (FLE). While the first two items are easily obtained, the FLE is usually estimated using an a priori technique and applied without any knowledge of real-time information. However, if the FLE can be estimated in real-time, particularly as it pertains to optical tracking, then the TRE can be estimated more robustly. In this paper, a method is presented where the FLE statistics are estimated from the latest measurement of the fiducial registration error (FRE) statistics. The solution is obtained by solving a linear system of equations of the form Ax=b for each marker at each time frame where x are the six independent FLE covariance parameters and b are the six independent estimated FRE covariance parameters. The A matrix is only a function of the tool geometry and hence the inverse of the matrix can be computed a priori and used at each instant in which the FLE estimation is required, hence minimizing the level of computation at each frame. When using a good estimate of the FRE statistics, Monte Carlo simulations demonstrate that the root mean square of the FLE can be computed within a range of 70-90 microm. Robust estimation of the TRE for an optically tracked tool, using a good estimate of the FLE, will provide two enhancements in IGS. First, better patient to image registration will be obtained by using the TRE of the optical tool as a weighting factor of point-based registration used to map the patient to image space. Second, the directionality of the TRE can be relayed back to the surgeon giving the surgeon the option

  6. Regional Gastrointestinal Transit Times in Patients With Carcinoid Diarrhea: Assessment With the Novel 3D-Transit System

    PubMed Central

    Gregersen, Tine; Haase, Anne-Mette; Schlageter, Vincent; Gronbaek, Henning; Krogh, Klaus

    2015-01-01

    Background/Aims The paucity of knowledge regarding gastrointestinal motility in patients with neuroendocrine tumors and carcinoid diarrhea restricts targeted treatment. 3D-Transit is a novel, minimally invasive, ambulatory method for description of gastrointestinal motility. The system has not yet been evaluated in any group of patients. We aimed to test the performance of 3D-Transit in patients with carcinoid diarrhea and to compare the patients’ regional gastrointestinal transit times (GITT) and colonic motility patterns with those of healthy subjects. Methods Fifteen healthy volunteers and seven patients with neuroendocrine tumor and at least 3 bowel movements per day were investigated with 3D-Transit and standard radiopaque markers. Results Total GITT assessed with 3D-Transit and radiopaque markers were well correlated (Spearman’s rho = 0.64, P = 0.002). Median total GITT was 12.5 (range: 8.5–47.2) hours in patients versus 25.1 (range: 13.1–142.3) hours in healthy (P = 0.007). There was no difference in gastric emptying (P = 0.778). Median small intestinal transit time was 3.8 (range: 1.4–5.5) hours in patients versus 4.4 (range: 1.8–7.2) hours in healthy subjects (P = 0.044). Median colorectal transit time was 5.2 (range: 2.9–40.1) hours in patients versus 18.1 (range: 5.0–134.0) hours in healthy subjects (P = 0.012). Median frequency of pansegmental colonic movements was 0.45 (range: 0.03–1.02) per hour in patients and 0.07 (range: 0–0.61) per hour in healthy subjects (P = 0.045). Conclusions Three-dimensional Transit allows assessment of regional GITT in patients with diarrhea. Patients with carcinoid diarrhea have faster than normal gastrointestinal transit due to faster small intestinal and colorectal transit times. The latter is caused by an increased frequency of pansegmental colonic movements. PMID:26130638

  7. Real-Time Estimation of 3-D Needle Shape and Deflection for MRI-Guided Interventions

    PubMed Central

    Park, Yong-Lae; Elayaperumal, Santhi; Daniel, Bruce; Ryu, Seok Chang; Shin, Mihye; Savall, Joan; Black, Richard J.; Moslehi, Behzad; Cutkosky, Mark R.

    2015-01-01

    We describe a MRI-compatible biopsy needle instrumented with optical fiber Bragg gratings for measuring bending deflections of the needle as it is inserted into tissues. During procedures, such as diagnostic biopsies and localized treatments, it is useful to track any tool deviation from the planned trajectory to minimize positioning errors and procedural complications. The goal is to display tool deflections in real time, with greater bandwidth and accuracy than when viewing the tool in MR images. A standard 18 ga × 15 cm inner needle is prepared using a fixture, and 350-μm-deep grooves are created along its length. Optical fibers are embedded in the grooves. Two sets of sensors, located at different points along the needle, provide an estimate of the bent profile, as well as temperature compensation. Tests of the needle in a water bath showed that it produced no adverse imaging artifacts when used with the MR scanner. PMID:26405428

  8. Detection of hidden objects using a real-time 3-D millimeter-wave imaging system

    NASA Astrophysics Data System (ADS)

    Rozban, Daniel; Aharon, Avihai; Levanon, Assaf; Abramovich, Amir; Yitzhaky, Yitzhak; Kopeika, N. S.

    2014-10-01

    Millimeter (mm)and sub-mm wavelengths or terahertz (THz) band have several properties that motivate their use in imaging for security applications such as recognition of hidden objects, dangerous materials, aerosols, imaging through walls as in hostage situations, and also in bad weather conditions. There is no known ionization hazard for biological tissue, and atmospheric degradation of THz radiation is relatively low for practical imaging distances. We recently developed a new technology for the detection of THz radiation. This technology is based on very inexpensive plasma neon indicator lamps, also known as Glow Discharge Detector (GDD), that can be used as very sensitive THz radiation detectors. Using them, we designed and constructed a Focal Plane Array (FPA) and obtained recognizable2-dimensional THz images of both dielectric and metallic objects. Using THz wave it is shown here that even concealed weapons made of dielectric material can be detected. An example is an image of a knife concealed inside a leather bag and also under heavy clothing. Three-dimensional imaging using radar methods can enhance those images since it can allow the isolation of the concealed objects from the body and environmental clutter such as nearby furniture or other people. The GDDs enable direct heterodyning between the electric field of the target signal and the reference signal eliminating the requirement for expensive mixers, sources, and Low Noise Amplifiers (LNAs).We expanded the ability of the FPA so that we are able to obtain recognizable 2-dimensional THz images in real time. We show here that the THz detection of objects in three dimensions, using FMCW principles is also applicable in real time. This imaging system is also shown here to be capable of imaging objects from distances allowing standoff detection of suspicious objects and humans from large distances.

  9. Time-Domain Filtering of Metasurfaces

    NASA Astrophysics Data System (ADS)

    Wakatsuchi, Hiroki

    2015-11-01

    In general electromagnetic response of each material to a continuous wave does not vary in time domain if the frequency component remains the same. Recently, it turned out that integrating several circuit elements including schottky diodes with periodically metallised surfaces, or the so-called metasurfaces, leads to selectively absorbing specific types of waveforms or pulse widths even at the same frequency. These waveform-selective metasurfaces effectively showed different absorbing performances for different widths of pulsed sine waves by gradually varying their electromagnetic responses in time domain. Here we study time-filtering effects of such circuit-based metasurfaces illuminated by continuous sine waves. Moreover, we introduce extra circuit elements to these structures to enhance the time-domain control capability. These time-varying properties are expected to give us another degree of freedom to control electromagnetic waves and thus contribute to developing new kinds of electromagnetic applications and technologies, e.g. time-windowing wireless communications and waveform conversion.

  10. Time-Domain Filtering of Metasurfaces.

    PubMed

    Wakatsuchi, Hiroki

    2015-01-01

    In general electromagnetic response of each material to a continuous wave does not vary in time domain if the frequency component remains the same. Recently, it turned out that integrating several circuit elements including schottky diodes with periodically metallised surfaces, or the so-called metasurfaces, leads to selectively absorbing specific types of waveforms or pulse widths even at the same frequency. These waveform-selective metasurfaces effectively showed different absorbing performances for different widths of pulsed sine waves by gradually varying their electromagnetic responses in time domain. Here we study time-filtering effects of such circuit-based metasurfaces illuminated by continuous sine waves. Moreover, we introduce extra circuit elements to these structures to enhance the time-domain control capability. These time-varying properties are expected to give us another degree of freedom to control electromagnetic waves and thus contribute to developing new kinds of electromagnetic applications and technologies, e.g. time-windowing wireless communications and waveform conversion. PMID:26564027

  11. Time-Domain Filtering of Metasurfaces

    PubMed Central

    Wakatsuchi, Hiroki

    2015-01-01

    In general electromagnetic response of each material to a continuous wave does not vary in time domain if the frequency component remains the same. Recently, it turned out that integrating several circuit elements including schottky diodes with periodically metallised surfaces, or the so-called metasurfaces, leads to selectively absorbing specific types of waveforms or pulse widths even at the same frequency. These waveform-selective metasurfaces effectively showed different absorbing performances for different widths of pulsed sine waves by gradually varying their electromagnetic responses in time domain. Here we study time-filtering effects of such circuit-based metasurfaces illuminated by continuous sine waves. Moreover, we introduce extra circuit elements to these structures to enhance the time-domain control capability. These time-varying properties are expected to give us another degree of freedom to control electromagnetic waves and thus contribute to developing new kinds of electromagnetic applications and technologies, e.g. time-windowing wireless communications and waveform conversion. PMID:26564027

  12. Switchable field-tuned control of magnetic domain wall pinning along Co microwires by 3D e-beam lithographed structures

    NASA Astrophysics Data System (ADS)

    Blanco-Roldán, C.; Quirós, C.; Rodriguez-Rodriguez, G.; Vélez, M.; Martín, J. I.; Alameda, J. M.

    2016-02-01

    Three-dimensional magnetic circuits composed of Co microwires crossed by elevated Co bridges have been patterned on Si substrate by e-beam lithography and lift-off process. The lithographic procedure includes a double resist procedure that optimizes the shape of the bridge, so that 200 nm air gaps can be routinely achieved in between the wire and bridge elements. Microwire magnetization reversal processes have been analyzed by magneto-optical Kerr effect microscopy with different remanent bridge configurations. When the Co bridge is magnetized along the in-plane direction parallel to the wire axis, its stray field induces a marked pinning effect on domain wall propagation along the wire below it, even without being in contact. Changing the sign of the remanent state of the bridge, domain wall pinning can be selected to occur in either the ascending or descending branches of the wire hysteresis loop. Thus, these wire-bridge 3D circuits provide a simple system for tunable domain wall pinning controllable through the pre-recorded bridge remanent state.

  13. Random center vortex lines in continuous 3D space-time

    NASA Astrophysics Data System (ADS)

    Höllwieser, Roman; Altarawneh, Derar; Engelhardt, Michael

    2016-01-01

    We present a model of center vortices, represented by closed random lines in continuous 2+1-dimensional space-time. These random lines are modeled as being piece-wise linear and an ensemble is generated by Monte Carlo methods. The physical space in which the vortex lines are defined is a cuboid with periodic boundary conditions. Besides moving, growing and shrinking of the vortex configuration, also reconnections are allowed. Our ensemble therefore contains not a fixed, but a variable number of closed vortex lines. This is expected to be important for realizing the deconfining phase transition. Using the model, we study both vortex percolation and the potential V(R) between quark and anti-quark as a function of distance R at different vortex densities, vortex segment lengths, reconnection conditions and at different temperatures. We have found three deconfinement phase transitions, as a function of density, as a function of vortex segment length, and as a function of temperature. The model reproduces the qualitative features of confinement physics seen in SU(2) Yang-Mills theory.

  14. Left ventricular endocardial surface detection based on real-time 3D echocardiographic data

    NASA Technical Reports Server (NTRS)

    Corsi, C.; Borsari, M.; Consegnati, F.; Sarti, A.; Lamberti, C.; Travaglini, A.; Shiota, T.; Thomas, J. D.

    2001-01-01

    OBJECTIVE: A new computerized semi-automatic method for left ventricular (LV) chamber segmentation is presented. METHODS: The LV is imaged by real-time three-dimensional echocardiography (RT3DE). The surface detection model, based on level set techniques, is applied to RT3DE data for image analysis. The modified level set partial differential equation we use is solved by applying numerical methods for conservation laws. The initial conditions are manually established on some slices of the entire volume. The solution obtained for each slice is a contour line corresponding with the boundary between LV cavity and LV endocardium. RESULTS: The mathematical model has been applied to sequences of frames of human hearts (volume range: 34-109 ml) imaged by 2D and reconstructed off-line and RT3DE data. Volume estimation obtained by this new semi-automatic method shows an excellent correlation with those obtained by manual tracing (r = 0.992). Dynamic change of LV volume during the cardiac cycle is also obtained. CONCLUSION: The volume estimation method is accurate; edge based segmentation, image completion and volume reconstruction can be accomplished. The visualization technique also allows to navigate into the reconstructed volume and to display any section of the volume.

  15. Dynamic shape modeling of the mitral valve from real-time 3D ultrasound images using continuous medial representation

    NASA Astrophysics Data System (ADS)

    Pouch, Alison M.; Yushkevich, Paul A.; Jackson, Benjamin M.; Gorman, Joseph H., III; Gorman, Robert C.; Sehgal, Chandra M.

    2012-03-01

    Purpose: Patient-specific shape analysis of the mitral valve from real-time 3D ultrasound (rt-3DUS) has broad application to the assessment and surgical treatment of mitral valve disease. Our goal is to demonstrate that continuous medial representation (cm-rep) is an accurate valve shape representation that can be used for statistical shape modeling over the cardiac cycle from rt-3DUS images. Methods: Transesophageal rt-3DUS data acquired from 15 subjects with a range of mitral valve pathology were analyzed. User-initialized segmentation with level sets and symmetric diffeomorphic normalization delineated the mitral leaflets at each time point in the rt-3DUS data series. A deformable cm-rep was fitted to each segmented image of the mitral leaflets in the time series, producing a 4D parametric representation of valve shape in a single cardiac cycle. Model fitting accuracy was evaluated by the Dice overlap, and shape interpolation and principal component analysis (PCA) of 4D valve shape were performed. Results: Of the 289 3D images analyzed, the average Dice overlap between each fitted cm-rep and its target segmentation was 0.880+/-0.018 (max=0.912, min=0.819). The results of PCA represented variability in valve morphology and localized leaflet thickness across subjects. Conclusion: Deformable medial modeling accurately captures valve geometry in rt-3DUS images over the entire cardiac cycle and enables statistical shape analysis of the mitral valve.

  16. Lapse-time dependent coda-wave depth sensitivity to local velocity perturbations in 3-D heterogeneous elastic media

    NASA Astrophysics Data System (ADS)

    Obermann, Anne; Planès, Thomas; Hadziioannou, Céline; Campillo, Michel

    2016-07-01

    In the context of seismic monitoring, recent studies made successful use of seismic coda waves to locate medium changes on the horizontal plane. Locating the depth of the changes, however, remains a challenge. In this paper, we use 3-D wavefield simulations to address two problems: firstly, we evaluate the contribution of surface and body wave sensitivity to a change at depth. We introduce a thin layer with a perturbed velocity at different depths and measure the apparent relative velocity changes due to this layer at different times in the coda and for different degrees of heterogeneity of the model. We show that the depth sensitivity can be modelled as a linear combination of body- and surface-wave sensitivity. The lapse-time dependent sensitivity ratio of body waves and surface waves can be used to build 3-D sensitivity kernels for imaging purposes. Secondly, we compare the lapse-time behavior in the presence of a perturbation in horizontal and vertical slabs to address, for instance, the origin of the velocity changes detected after large earthquakes.

  17. Real-time 3D visualization of the thoraco-abdominal surface during breathing with body movement and deformation extraction.

    PubMed

    Povšič, K; Jezeršek, M; Možina, J

    2015-07-01

    Real-time 3D visualization of the breathing displacements can be a useful diagnostic tool in order to immediately observe the most active regions on the thoraco-abdominal surface. The developed method is capable of separating non-relevant torso movement and deformations from the deformations that are solely related to breathing. This makes it possible to visualize only the breathing displacements. The system is based on the structured laser triangulation principle, with simultaneous spatial and color data acquisition of the thoraco-abdominal region. Based on the tracking of the attached passive markers, the torso movement and deformation is compensated using rigid and non-rigid transformation models on the three-dimensional (3D) data. The total time of 3D data processing together with visualization equals 20 ms per cycle.In vitro verification of the rigid movement extraction was performed using the iterative closest point algorithm as a reference. Furthermore, a volumetric evaluation on a live subject was performed to establish the accuracy of the rigid and non-rigid model. The root mean square deviation between the measured and the reference volumes shows an error of  ±0.08 dm(3) for rigid movement extraction. Similarly, the error was calculated to be  ±0.02 dm(3) for torsional deformation extraction and  ±0.11 dm(3) for lateral bending deformation extraction. The results confirm that during the torso movement and deformation, the proposed method is sufficiently accurate to visualize only the displacements related to breathing. The method can be used, for example, during the breathing exercise on an indoor bicycle or a treadmill. PMID:26020444

  18. Low-power 20-meter 3D ranging SPAD camera based on continuous-wave indirect time-of-flight

    NASA Astrophysics Data System (ADS)

    Bellisai, S.; Ferretti, L.; Villa, F.; Ruggeri, A.; Tisa, S.; Tosi, A.; Zappa, F.

    2012-06-01

    Three dimensional (3D) image acquisitions is the enabling technology of a great number of applications; culture heritage morphology study, industrial robotics, automotive active safety and security access control are example of applications. The most important feature is the high frame-rate, to detect very fast events within the acquired scenes. In order to reduce the computational complexity, Time-of-Flight algorithms for single sensor cameras are used. To achieve high-frame rate and high distance measurement accuracy it is important to collect the most part of the reflected light using sensor with very high sensitivity, allowing the implementation of a low-power light source. We designed and developed a single-photon detection based 3D ranging camera, capable to acquire distance image up to 22.5 m, with a resolution down to one centimeter. The light source used in this prototype employs 8 laser diodes sinusoidally modulated. The imager used in the application is based on Single-Photon Avalanche Diodes (SPADs) fabricated in a standard CMOS 0.35 μm technology. The sensor has 1024 pixels arranged in a 32x32 squared layout, with overall dimensions of 3.5mm x 3.5mm. The camera acquires 3D images through the continuous-wave indirect Time of Flight (cw-iTOF) technique. The typical frame-rate is 20 fps while the theoretical maximum frame-rate is 5 kfps. The precision is better than 5 cm within 22.5 m range, and can be effectively used in indoor applications, e.g. in industrial environment.

  19. 1D-3D hybrid modeling—from multi-compartment models to full resolution models in space and time

    PubMed Central

    Grein, Stephan; Stepniewski, Martin; Reiter, Sebastian; Knodel, Markus M.; Queisser, Gillian

    2014-01-01

    Investigation of cellular and network dynamics in the brain by means of modeling and simulation has evolved into a highly interdisciplinary field, that uses sophisticated modeling and simulation approaches to understand distinct areas of brain function. Depending on the underlying complexity, these models vary in their level of detail, in order to cope with the attached computational cost. Hence for large network simulations, single neurons are typically reduced to time-dependent signal processors, dismissing the spatial aspect of each cell. For single cell or networks with relatively small numbers of neurons, general purpose simulators allow for space and time-dependent simulations of electrical signal processing, based on the cable equation theory. An emerging field in Computational Neuroscience encompasses a new level of detail by incorporating the full three-dimensional morphology of cells and organelles into three-dimensional, space and time-dependent, simulations. While every approach has its advantages and limitations, such as computational cost, integrated and methods-spanning simulation approaches, depending on the network size could establish new ways to investigate the brain. In this paper we present a hybrid simulation approach, that makes use of reduced 1D-models using e.g., the NEURON simulator—which couples to fully resolved models for simulating cellular and sub-cellular dynamics, including the detailed three-dimensional morphology of neurons and organelles. In order to couple 1D- and 3D-simulations, we present a geometry-, membrane potential- and intracellular concentration mapping framework, with which graph- based morphologies, e.g., in the swc- or hoc-format, are mapped to full surface and volume representations of the neuron and computational data from 1D-simulations can be used as boundary conditions for full 3D simulations and vice versa. Thus, established models and data, based on general purpose 1D-simulators, can be directly coupled to

  20. A GRASS GIS based Spatio-Temporal Algebra for Raster-, 3D Raster- and Vector Time Series Data

    NASA Astrophysics Data System (ADS)

    Leppelt, Thomas; Gebbert, Sören

    2015-04-01

    Enhancing the well known and widely used map algebra proposed by Dr. Charles Dana Tomlin [1] with the time dimension is an ongoing research topic. The efficient processing of large time series of raster, 3D raster and vector datasets, e. g. raster datasets for temperature or precipitations on continental scale, requires a sophisticated spatio-temporal algebra that is capable of handling datasets with different temporal granularities and spatio-temporal extents. With the temporal enabled GRASS GIS [2] and the GRASS GIS Temporal Framework new spatio-temporal data types are available in GRASS GIS 7, called space time datasets. These space time datasets represent time series of raster, 3D raster and vector map layers. Furthermore the temporal framework provides a wide range of functionalities to support the implementation of a temporal algebra. While spatial capabilities of GRASS GIS are used to perform the spatial processing of the time stamped map layers that are registered in a space time dataset, the temporal processing is provided by the GRASS GIS temporal framework that supports time intervals and time instances. Mixing time instance and time intervals as well as gaps, overlapping or inclusion of intervals and instances is possible. Hence this framework allows an arbitrary layout of the time dimension. We implemented two ways to process space time datasets with arbitrary temporal layout, the temporal topology and the granularity based spatio-temporal algebra. The algebra provides the functionality to define complex spatio-temporal topological operators that process time and space in a single expression. The algebra includes methods to select map layers from space time datasets based on their temporal relations, to temporally shift time stamped map layers, to create temporal buffer and to snap time instances of time stamped map layers to create a valid temporal topology. In addition spatio-temporal operations can be evaluated within conditional statements. These

  1. High Temporal and Spatial Resolution 3D Time-Resolved Contrast-Enhanced MR Angiography of the Hands and Feet

    PubMed Central

    Haider, Clifton R.; Riederer, Stephen J.; Borisch, Eric A.; Glockner, James F.; Grimm, Roger C.; Hulshizer, Thomas C.; Macedo, Thanila A.; Mostardi, Petrice M.; Rossman, Phillip J.; Vrtiska, Terri J.; Young, Phillip M.

    2010-01-01

    Methods are described for generating 3D time-resolved contrast-enhanced MR angiograms of the hands and feet. Given targeted spatial resolution and frame times, it is shown that acceleration of about one order of magnitude or more is necessary. This is obtained by a combination of 2D Sensitivity Encoding (SENSE) and homodyne (HD) acceleration methods. Image update times from 3.4 to 6.8 sec are provided in conjunction with view sharing. Modular receiver coil arrays are described which can be designed to the targeted vascular region. Images representative of the technique are generated in the vasculature of the hands and feet in volunteers and in patient studies. PMID:21698702

  2. Phenylalanine-508 mediates a cytoplasmic-membrane domain contact in the CFTR 3D structure crucial to assembly and channel function.

    PubMed

    Serohijos, Adrian W R; Hegedus, Tamás; Aleksandrov, Andrei A; He, Lihua; Cui, Liying; Dokholyan, Nikolay V; Riordan, John R

    2008-03-01

    Deletion of phenylalanine-508 (Phe-508) from the N-terminal nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) transporter family, disrupts both its folding and function and causes most cystic fibrosis. Most mutant nascent chains do not pass quality control in the ER, and those that do remain thermally unstable, only partially functional, and are rapidly endocytosed and degraded. Although the lack of the Phe-508 peptide backbone diminishes the NBD1 folding yield, the absence of the aromatic side chain is primarily responsible for defective CFTR assembly and channel gating. However, the site of interdomain contact by the side chain is unknown as is the high-resolution 3D structure of the complete protein. Here we present a 3D structure of CFTR, constructed by molecular modeling and supported biochemically, in which Phe-508 mediates a tertiary interaction between the surface of NBD1 and a cytoplasmic loop (CL4) in the C-terminal membrane-spanning domain (MSD2). This crucial cytoplasmic membrane interface, which is dynamically involved in regulation of channel gating, explains the known sensitivity of CFTR assembly to many disease-associated mutations in CL4 as well as NBD1 and provides a sharply focused target for small molecules to treat CF. In addition to identifying a key intramolecular site to be repaired therapeutically, our findings advance understanding of CFTR structure and function and provide a platform for focused biochemical studies of other features of this unique ABC ion channel. PMID:18305154

  3. Phenylalanine-508 mediates a cytoplasmic–membrane domain contact in the CFTR 3D structure crucial to assembly and channel function

    PubMed Central

    Serohijos, Adrian W. R.; Hegedűs, Tamás; Aleksandrov, Andrei A.; He, Lihua; Cui, Liying; Dokholyan, Nikolay V.; Riordan, John R.

    2008-01-01

    Deletion of phenylalanine-508 (Phe-508) from the N-terminal nucleotide-binding domain (NBD1) of the cystic fibrosis transmembrane conductance regulator (CFTR), a member of the ATP-binding cassette (ABC) transporter family, disrupts both its folding and function and causes most cystic fibrosis. Most mutant nascent chains do not pass quality control in the ER, and those that do remain thermally unstable, only partially functional, and are rapidly endocytosed and degraded. Although the lack of the Phe-508 peptide backbone diminishes the NBD1 folding yield, the absence of the aromatic side chain is primarily responsible for defective CFTR assembly and channel gating. However, the site of interdomain contact by the side chain is unknown as is the high-resolution 3D structure of the complete protein. Here we present a 3D structure of CFTR, constructed by molecular modeling and supported biochemically, in which Phe-508 mediates a tertiary interaction between the surface of NBD1 and a cytoplasmic loop (CL4) in the C-terminal membrane-spanning domain (MSD2). This crucial cytoplasmic membrane interface, which is dynamically involved in regulation of channel gating, explains the known sensitivity of CFTR assembly to many disease-associated mutations in CL4 as well as NBD1 and provides a sharply focused target for small molecules to treat CF. In addition to identifying a key intramolecular site to be repaired therapeutically, our findings advance understanding of CFTR structure and function and provide a platform for focused biochemical studies of other features of this unique ABC ion channel. PMID:18305154

  4. Development of CT and 3D-CT Using Flat Panel Detector Based Real-Time Digital Radiography System

    SciTech Connect

    Ravindran, V. R.; Sreelakshmi, C.; Vibin

    2008-09-26

    The application of Digital Radiography in the Nondestructive Evaluation (NDE) of space vehicle components is a recent development in India. A Real-time DR system based on amorphous silicon Flat Panel Detector has been developed for the NDE of solid rocket motors at Rocket Propellant Plant of VSSC in a few years back. The technique has been successfully established for the nondestructive evaluation of solid rocket motors. The DR images recorded for a few solid rocket specimens are presented in the paper. The Real-time DR system is capable of generating sufficient digital X-ray image data with object rotation for the CT image reconstruction. In this paper the indigenous development of CT imaging based on the Realtime DR system for solid rocket motor is presented. Studies are also carried out to generate 3D-CT image from a set of adjacent CT images of the rocket motor. The capability of revealing the spatial location and characterisation of defect is demonstrated by the CT and 3D-CT images generated.

  5. Simultaneous real-time 3D photoacoustic tomography and EEG for neurovascular coupling study in an animal model of epilepsy

    NASA Astrophysics Data System (ADS)

    Wang, Bo; Xiao, Jiaying; Jiang, Huabei

    2014-08-01

    Objective. Neurovascular coupling in epilepsy is poorly understood; its study requires simultaneous monitoring of hemodynamic changes and neural activity in the brain. Approach. Here for the first time we present a combined real-time 3D photoacoustic tomography (PAT) and electrophysiology/electroencephalography (EEG) system for the study of neurovascular coupling in epilepsy, whose ability was demonstrated with a pentylenetetrazol (PTZ) induced generalized seizure model in rats. Two groups of experiments were carried out with different wavelengths to detect the changes of oxy-hemoglobin (HbO2) and deoxy-hemoglobin (HbR) signals in the rat brain. We extracted the average PAT signals of the superior sagittal sinus (SSS), and compared them with the EEG signal. Main results. Results showed that the seizure process can be divided into three stages. A ‘dip’ lasting for 1-2 min in the first stage and the following hyperfusion in the second stage were observed. The HbO2 signal and the HbR signal were generally negatively correlated. The change of blood flow was also estimated. All the acquired results here were in accordance with other published results. Significance. Compared to other existing functional neuroimaging tools, the method proposed here enables reliable tracking of hemodynamic signal with both high spatial and high temporal resolution in 3D, so it is more suitable for neurovascular coupling study of epilepsy.

  6. Fuzzy logic-based approach to wavelet denoising of 3D images produced by time-of-flight cameras.

    PubMed

    Jovanov, Ljubomir; Pižurica, Aleksandra; Philips, Wilfried

    2010-10-25

    In this paper we present a new denoising method for the depth images of a 3D imaging sensor, based on the time-of-flight principle. We propose novel ways to use luminance-like information produced by a time-of flight camera along with depth images. Firstly, we propose a wavelet-based method for estimating the noise level in depth images, using luminance information. The underlying idea is that luminance carries information about the power of the optical signal reflected from the scene and is hence related to the signal-to-noise ratio for every pixel within the depth image. In this way, we can efficiently solve the difficult problem of estimating the non-stationary noise within the depth images. Secondly, we use luminance information to better restore object boundaries masked with noise in the depth images. Information from luminance images is introduced into the estimation formula through the use of fuzzy membership functions. In particular, we take the correlation between the measured depth and luminance into account, and the fact that edges (object boundaries) present in the depth image are likely to occur in the luminance image as well. The results on real 3D images show a significant improvement over the state-of-the-art in the field. PMID:21164605

  7. Time-sequential autostereoscopic 3-D display with a novel directional backlight system based on volume-holographic optical elements.

    PubMed

    Hwang, Yong Seok; Bruder, Friedrich-Karl; Fäcke, Thomas; Kim, Seung-Cheol; Walze, Günther; Hagen, Rainer; Kim, Eun-Soo

    2014-04-21

    A novel directional backlight system based on volume-holographic optical elements (VHOEs) is demonstrated for time-sequential autostereoscopic three-dimensional (3-D) flat-panel displays. Here, VHOEs are employed to control the direction of light for a time-multiplexed display for each of the left and the right view. Those VHOEs are fabricated by recording interference patterns between collimated reference beams and diverging object beams for each of the left and right eyes on the volume holographic recording material. For this, self-developing photopolymer films (Bayfol® HX) were used, since those simplify the manufacturing process of VHOEs substantially. Here, the directional lights are similar to the collimated reference beams that were used to record the VHOEs and create two diffracted beams similar to the object beams used for recording the VHOEs. Then, those diffracted beams read the left and right images alternately shown on the LCD panel and form two converging viewing zones in front of the user's eyes. By this he can perceive the 3-D image. Theoretical predictions and experimental results are presented and the performance of the developed prototype is shown. PMID:24787867

  8. Time-domain robotic vision application

    NASA Technical Reports Server (NTRS)

    Tolliver, C. L.

    1987-01-01

    The quest for the highest resolution microwaves imaging and the principle of time-domain imaging is the primary motivation for recent developments in time-domain techniques. With the present technology fast time varying signals can now be measured and recorded both in magnitude and in phase. It has also enhanced the ability to extract relevant details concerning the scattering object. In the past, the inference of object geometry or shape from scattered signals has received substantial attention in radar technology. Various inverse scattering theories were proposed to develop analytical solutions to this problem. Furthermore, the random inversion, frequenty swept holography, and the synthetic radar imaging, all of which have two things in common: the physical optic far-field approximation and the utilization of the channels as an extra physical dimension, were also advanced significantly. Despite the inherent vectorial nature of electromagnetic waves, these scalar treatments have brought forth some promising results in practice with notable examples in subsurface and structure sounding. The use of time-domain imaging for space robotic vision applications was proposed. A multisensor approach to vision was shown to have several advantages over the video-only approach.

  9. Solitons for optical time-domain reflectometry

    NASA Astrophysics Data System (ADS)

    Levanon, Amikam; Friberg, Stephen R.; Fujii, Yoichi

    1996-06-01

    We describe the propagation of solitons in an optical time-domain reflectometry geometry. Intense nonsolitons usually broaden nonlinearly as they propagate out to a scatterer and broaden linearly as they return to their origin. In contrast, solitons propagate with a fixed pulse width or narrow on their way out to the scatterer. Returning, they broaden or narrow depending on their chirp at the scattering point. For a fixed return-pulse timing resolution we find 2.6 times or more energy can be launched when solitons are used than for normal dispersion pulses.

  10. Recovering Complex Conductivity from Frequency and Time Domain Geophysical Surveys

    NASA Astrophysics Data System (ADS)

    KANG, S.; Marchant, D.; Oldenburg, D.

    2013-12-01

    The electrical conductivity of earth materials can be frequency dependent. The bulk conductivity decreases with decreasing frequency because of the build-up of electric charges that occur under the application of an electric field. Effectively, the rock is electrically polarized. Finding the polarization response (often referred to as IP, Induced Polarization) can lead to economic benefits, as in the case of discovering sulphide minerals, but there is applicability in environmental problems, groundwater flow, and site characterization. We have the ability to model Maxwell's equations in 3D for complex conductivity in either the time or frequency domain. The challenge therefore is to invert the EM (electromagnetic) data to recover a four-dimensional conductivity (σ (ω, x, y, z)) using limited EM data generally acquired on, or above, the surface of the earth. At late times (or low frequencies) the static Maxwell's equation are valid and, if a background conductivity is known, then chargeability can be extracted. Unfortunately the static assumption is often violated and EM induction processes contaminate the sought signal. For example, signals in the time domain have three parts: a static on-time, an early-time inductive portion, and a late-time IP signal. Information about conductivity using the appropriate Maxwell's equations is available from each of these segments. The potential contamination of the IP from EM induction (often referred to as EM coupling) and the potential contamination of the EM signal from the IP data (IP coupling) can cause deleterious effects and must be addressed. The goal of this talk is to address such issues and outline a practical procedure for extracting IP information from existing time and frequency domain surveys.

  11. LHC RF System Time-Domain Simulation

    SciTech Connect

    Mastorides, T.; Rivetta, C.; /SLAC

    2010-09-14

    Non-linear time-domain simulations have been developed for the Positron-Electron Project (PEP-II) and the Large Hadron Collider (LHC). These simulations capture the dynamic behavior of the RF station-beam interaction and are structured to reproduce the technical characteristics of the system (noise contributions, non-linear elements, and more). As such, they provide useful results and insight for the development and design of future LLRF feedback systems. They are also a valuable tool for the study of diverse longitudinal beam dynamics effects such as coupled-bunch impedance driven instabilities and single bunch longitudinal emittance growth. Results from these studies and related measurements from PEP-II and LHC have been presented in multiple places. This report presents an example of the time-domain simulation implementation for the LHC.

  12. Time Domain Modelling of a Reciprocating Engine

    NASA Astrophysics Data System (ADS)

    Li, H.; Stone, B. J.

    1999-01-01

    This paper describes the application of a time domain systems approach to the modelling of a reciprocating engine. The engine model includes the varying inertia effects resulting from the motion of the piston and con-rod. The cylinder pressure measured under operating conditions is used to force the model and the resulting motion compared with the measured response. The results obtained indicate that the model is very good.

  13. [Measurement of left atrial and ventricular volumes in real-time 3D echocardiography. Validation by nuclear magnetic resonance

    NASA Technical Reports Server (NTRS)

    Bauer, F.; Shiota, T.; Qin, J. X.; White, R. D.; Thomas, J. D.

    2001-01-01

    The measurement of the left ventricular ejection fraction is important for the evaluation of cardiomyopathy and depends on the measurement of left ventricular volumes. There are no existing conventional echocardiographic means of measuring the true left atrial and ventricular volumes without mathematical approximations. The aim of this study was to test anew real time 3-dimensional echocardiographic system of calculating left atrial and ventricular volumes in 40 patients after in vitro validation. The volumes of the left atrium and ventricle acquired from real time 3-D echocardiography in the apical view, were calculated in 7 sections parallel to the surface of the probe and compared with atrial (10 patients) and ventricular (30 patients) volumes calculated by nuclear magnetic resonance with the simpson method and with volumes of water in balloons placed in a cistern. Linear regression analysis showed an excellent correlation between the real volume of water in the balloons and volumes given in real time 3-dimensional echocardiography (y = 0.94x + 5.5, r = 0.99, p < 0.001, D = -10 +/- 4.5 ml). A good correlation was observed between real time 3-dimensional echocardiography and nuclear magnetic resonance for the measurement of left atrial and ventricular volumes (y = 0.95x - 10, r = 0.91, p < 0.001, D = -14.8 +/- 19.5 ml and y = 0.87x + 10, r = 0.98, P < 0.001, D = -8.3 +/- 18.7 ml, respectively. The authors conclude that real time three-dimensional echocardiography allows accurate measurement of left heart volumes underlying the clinical potential of this new 3-D method.

  14. Time domain simulation and sound synthesis for the snare drum.

    PubMed

    Bilbao, Stefan

    2012-01-01

    The snare drum is a complex system, relying on the interaction of multiple components: the drumheads, or membranes, a set of snares, the surrounding acoustic field and an internal cavity. Because these components are multidimensional, and due to a strong distributed non-linearity (the snare interaction), many techniques used frequently in physical modeling synthesis applications, such as digital waveguides and modal methods are difficult to apply. In this article, finite difference time domain techniques are applied to a full 3D system, and various features of interest, such as the coupling between membranes, and the interaction between the membranes and the snares, are examined in detail. Also discussed are various numerical features, such as spurious splitting of degenerate modes and bandwidth limitation, and estimates of computational complexity are provided. Sound examples are presented. PMID:22280714

  15. Real-time processor for 3-D information extraction from image sequences by a moving area sensor

    NASA Astrophysics Data System (ADS)

    Hattori, Tetsuo; Nakada, Makoto; Kubo, Katsumi

    1990-11-01

    This paper presents a real time image processor for obtaining threedimensional( 3-D) distance information from image sequence caused by a moving area sensor. The processor has been developed for an automated visual inspection robot system (pilot system) with an autonomous vehicle which moves around avoiding obstacles in a power plant and checks whether there are defects or abnormal phenomena such as steam leakage from valves. The processor detects the distance between objects in the input image and the area sensor deciding corresponding points(pixels) between the first input image and the last one by tracing the loci of edges through the sequence of sixteen images. The hardware which plays an important role is two kinds of boards: mapping boards which can transform X-coordinate (horizontal direction) and Y-coordinate (vertical direction) for each horizontal row of images and a regional labelling board which extracts the connected loci of edges through image sequence. This paper also shows the whole processing flow of the distance detection algorithm. Since the processor can continuously process images ( 512x512x8 [pixels*bits per frame] ) at the NTSC video rate it takes about O. 7[sec] to measure the 3D distance by sixteen input images. The error rate of the measurement is maximum 10 percent when the area sensor laterally moves the range of 20 [centimeters] and when the measured scene including complicated background is at a distance of 4 [meters] from

  16. C-ME: A 3D Community-Based, Real-Time Collaboration Tool for Scientific Research and Training

    PubMed Central

    Kolatkar, Anand; Kennedy, Kevin; Halabuk, Dan; Kunken, Josh; Marrinucci, Dena; Bethel, Kelly; Guzman, Rodney; Huckaby, Tim; Kuhn, Peter

    2008-01-01

    The need for effective collaboration tools is growing as multidisciplinary proteome-wide projects and distributed research teams become more common. The resulting data is often quite disparate, stored in separate locations, and not contextually related. Collaborative Molecular Modeling Environment (C-ME) is an interactive community-based collaboration system that allows researchers to organize information, visualize data on a two-dimensional (2-D) or three-dimensional (3-D) basis, and share and manage that information with collaborators in real time. C-ME stores the information in industry-standard databases that are immediately accessible by appropriate permission within the computer network directory service or anonymously across the internet through the C-ME application or through a web browser. The system addresses two important aspects of collaboration: context and information management. C-ME allows a researcher to use a 3-D atomic structure model or a 2-D image as a contextual basis on which to attach and share annotations to specific atoms or molecules or to specific regions of a 2-D image. These annotations provide additional information about the atomic structure or image data that can then be evaluated, amended or added to by other project members. PMID:18286178

  17. SIMULTANEOUS BILATERAL REAL-TIME 3-D TRANSCRANIAL ULTRASOUND IMAGING AT 1 MHZ THROUGH POOR ACOUSTIC WINDOWS

    PubMed Central

    Lindsey, Brooks D.; Nicoletto, Heather A.; Bennett, Ellen R.; Laskowitz, Daniel T.; Smith, Stephen W.

    2013-01-01

    Ultrasound imaging has been proposed as a rapid, portable alternative imaging modality to examine stroke patients in pre-hospital or emergency room settings. However, in performing transcranial ultrasound examinations, 8%–29% of patients in a general population may present with window failure, in which case it is not possible to acquire clinically useful sonographic information through the temporal bone acoustic window. In this work, we describe the technical considerations, design and fabrication of low-frequency (1.2 MHz), large aperture (25.3 mm) sparse matrix array transducers for 3-D imaging in the event of window failure. These transducers are integrated into a system for real-time 3-D bilateral transcranial imaging—the ultrasound brain helmet—and color flow imaging capabilities at 1.2 MHz are directly compared with arrays operating at 1.8 MHz in a flow phantom with attenuation comparable to the in vivo case. Contrast-enhanced imaging allowed visualization of arteries of the Circle of Willis in 5 of 5 subjects and 8 of 10 sides of the head despite probe placement outside of the acoustic window. Results suggest that this type of transducer may allow acquisition of useful images either in individuals with poor windows or outside of the temporal acoustic window in the field. PMID:23415287

  18. Metrology for terahertz time-domain spectrometers

    NASA Astrophysics Data System (ADS)

    Molloy, John F.; Naftaly, Mira

    2015-12-01

    In recent years the terahertz time-domain spectrometer (THz TDS) [1] has emerged as a key measurement device for spectroscopic investigations in the frequency range of 0.1-5 THz. To date, almost every type of material has been studied using THz TDS, including semiconductors, ceramics, polymers, metal films, liquid crystals, glasses, pharmaceuticals, DNA molecules, proteins, gases, composites, foams, oils, and many others. Measurements with a TDS are made in the time domain; conversion from the time domain data to a frequency spectrum is achieved by applying the Fourier Transform, calculated numerically using the Fast Fourier Transform (FFT) algorithm. As in many other types of spectrometer, THz TDS requires that the sample data be referenced to similarly acquired data with no sample present. Unlike frequency-domain spectrometers which detect light intensity and measure absorption spectra, a TDS records both amplitude and phase information, and therefore yields both the absorption coefficient and the refractive index of the sample material. The analysis of the data from THz TDS relies on the assumptions that: a) the frequency scale is accurate; b) the measurement of THz field amplitude is linear; and c) that the presence of the sample does not affect the performance characteristics of the instrument. The frequency scale of a THz TDS is derived from the displacement of the delay line; via FFT, positioning errors may give rise to frequency errors that are difficult to quantify. The measurement of the field amplitude in a THz TDS is required to be linear with a dynamic range of the order of 10 000. And attention must be given to the sample positioning and handling in order to avoid sample-related errors.

  19. Longitudinal, 3D Imaging of Collagen Remodeling in Murine Hypertrophic Scars In Vivo Using Polarization-Sensitive Optical Frequency Domain Imaging.

    PubMed

    Lo, William C Y; Villiger, Martin; Golberg, Alexander; Broelsch, G Felix; Khan, Saiqa; Lian, Christine G; Austen, William G; Yarmush, Martin; Bouma, Brett E

    2016-01-01

    Hypertrophic scars (HTS), frequently seen after traumatic injuries and surgery, remain a major clinical challenge because of the limited success of existing therapies. A significant obstacle to understanding HTS etiology is the lack of tools to monitor scar remodeling longitudinally and noninvasively. We present an in vivo, label-free technique using polarization-sensitive optical frequency domain imaging for the 3D, longitudinal assessment of collagen remodeling in murine HTS. In this study, HTS was induced with a mechanical tension device for 4-10 days on incisional wounds and imaged up to 1 month after device removal; an excisional HTS model was also imaged at 6 months after injury to investigate deeper and more mature scars. We showed that local retardation and degree of polarization provide a robust signature for HTS. Compared with normal skin with heterogeneous local retardation and low degree of polarization, HTS was characterized by an initially low local retardation, which increased as collagen fibers remodeled, and a persistently high degree of polarization. This study demonstrates that polarization-sensitive optical frequency domain imaging offers a powerful tool to gain significant biological insights into HTS remodeling by enabling longitudinal assessment of collagen in vivo, which is critical to elucidating HTS etiology and developing more effective HTS therapies. PMID:26763427

  20. A 3D, fully Eulerian, VOF-based solver to study the interaction between two fluids and moving rigid bodies using the fictitious domain method

    NASA Astrophysics Data System (ADS)

    Pathak, Ashish; Raessi, Mehdi

    2016-04-01

    We present a three-dimensional (3D) and fully Eulerian approach to capturing the interaction between two fluids and moving rigid structures by using the fictitious domain and volume-of-fluid (VOF) methods. The solid bodies can have arbitrarily complex geometry and can pierce the fluid-fluid interface, forming contact lines. The three-phase interfaces are resolved and reconstructed by using a VOF-based methodology. Then, a consistent scheme is employed for transporting mass and momentum, allowing for simulations of three-phase flows of large density ratios. The Eulerian approach significantly simplifies numerical resolution of the kinematics of rigid bodies of complex geometry and with six degrees of freedom. The fluid-structure interaction (FSI) is computed using the fictitious domain method. The methodology was developed in a message passing interface (MPI) parallel framework accelerated with graphics processing units (GPUs). The computationally intensive solution of the pressure Poisson equation is ported to GPUs, while the remaining calculations are performed on CPUs. The performance and accuracy of the methodology are assessed using an array of test cases, focusing individually on the flow solver and the FSI in surface-piercing configurations. Finally, an application of the proposed methodology in simulations of the ocean wave energy converters is presented.

  1. Design and application of real-time visual attention model for the exploration of 3D virtual environments.

    PubMed

    Hillaire, Sébastien; Lécuyer, Anatole; Regia-Corte, Tony; Cozot, Rémi; Royan, Jérôme; Breton, Gaspard

    2012-03-01

    This paper studies the design and application of a novel visual attention model designed to compute user's gaze position automatically, i.e., without using a gaze-tracking system. The model we propose is specifically designed for real-time first-person exploration of 3D virtual environments. It is the first model adapted to this context which can compute in real time a continuous gaze point position instead of a set of 3D objects potentially observed by the user. To do so, contrary to previous models which use a mesh-based representation of visual objects, we introduce a representation based on surface-elements. Our model also simulates visual reflexes and the cognitive processes which take place in the brain such as the gaze behavior associated to first-person navigation in the virtual environment. Our visual attention model combines both bottom-up and top-down components to compute a continuous gaze point position on screen that hopefully matches the user's one. We conducted an experiment to study and compare the performance of our method with a state-of-the-art approach. Our results are found significantly better with sometimes more than 100 percent of accuracy gained. This suggests that computing a gaze point in a 3D virtual environment in real time is possible and is a valid approach, compared to object-based approaches. Finally, we expose different applications of our model when exploring virtual environments. We present different algorithms which can improve or adapt the visual feedback of virtual environments based on gaze information. We first propose a level-of-detail approach that heavily relies on multiple-texture sampling. We show that it is possible to use the gaze information of our visual attention model to increase visual quality where the user is looking, while maintaining a high-refresh rate. Second, we introduce the use of the visual attention model in three visual effects inspired by the human visual system namely: depth-of-field blur, camera

  2. Automated real-time search and analysis algorithms for a non-contact 3D profiling system

    NASA Astrophysics Data System (ADS)

    Haynes, Mark; Wu, Chih-Hang John; Beck, B. Terry; Peterman, Robert J.

    2013-04-01

    The purpose of this research is to develop a new means of identifying and extracting geometrical feature statistics from a non-contact precision-measurement 3D profilometer. Autonomous algorithms have been developed to search through large-scale Cartesian point clouds to identify and extract geometrical features. These algorithms are developed with the intent of providing real-time production quality control of cold-rolled steel wires. The steel wires in question are prestressing steel reinforcement wires for concrete members. The geometry of the wire is critical in the performance of the overall concrete structure. For this research a custom 3D non-contact profilometry system has been developed that utilizes laser displacement sensors for submicron resolution surface profiling. Optimizations in the control and sensory system allow for data points to be collected at up to an approximate 400,000 points per second. In order to achieve geometrical feature extraction and tolerancing with this large volume of data, the algorithms employed are optimized for parsing large data quantities. The methods used provide a unique means of maintaining high resolution data of the surface profiles while keeping algorithm running times within practical bounds for industrial application. By a combination of regional sampling, iterative search, spatial filtering, frequency filtering, spatial clustering, and template matching a robust feature identification method has been developed. These algorithms provide an autonomous means of verifying tolerances in geometrical features. The key method of identifying the features is through a combination of downhill simplex and geometrical feature templates. By performing downhill simplex through several procedural programming layers of different search and filtering techniques, very specific geometrical features can be identified within the point cloud and analyzed for proper tolerancing. Being able to perform this quality control in real time

  3. 3-D imaging of large scale buried structure by 1-D inversion of very early time electromagnetic (VETEM) data

    USGS Publications Warehouse

    Aydmer, A.A.; Chew, W.C.; Cui, T.J.; Wright, D.L.; Smith, D.V.; Abraham, J.D.

    2001-01-01

    A simple and efficient method for large scale three-dimensional (3-D) subsurface imaging of inhomogeneous background is presented. One-dimensional (1-D) multifrequency distorted Born iterative method (DBIM) is employed in the inversion. Simulation results utilizing synthetic scattering data are given. Calibration of the very early time electromagnetic (VETEM) experimental waveforms is detailed along with major problems encountered in practice and their solutions. This discussion is followed by the results of a large scale application of the method to the experimental data provided by the VETEM system of the U.S. Geological Survey. The method is shown to have a computational complexity that is promising for on-site inversion.

  4. Incorporation of 3-D Scanning Lidar Data into Google Earth for Real-time Air Pollution Observation

    NASA Astrophysics Data System (ADS)

    Chiang, C.; Nee, J.; Das, S.; Sun, S.; Hsu, Y.; Chiang, H.; Chen, S.; Lin, P.; Chu, J.; Su, C.; Lee, W.; Su, L.; Chen, C.

    2011-12-01

    3-D Differential Absorption Scanning Lidar (DIASL) system has been designed with small size, light weight, and suitable for installation in various vehicles and places for monitoring of air pollutants and displays a detailed real-time temporal and spatial variability of trace gases via the Google Earth. The fast scanning techniques and visual information can rapidly identify the locations and sources of the polluted gases and assess the most affected areas. It is helpful for Environmental Protection Agency (EPA) to protect the people's health and abate the air pollution as quickly as possible. The distributions of the atmospheric pollutants and their relationship with local metrological parameters measured with ground based instruments will also be discussed. Details will be presented in the upcoming symposium.

  5. Docking and 3D-QSAR (quantitative structure activity relationship) studies of flavones, the potent inhibitors of p-glycoprotein targeting the nucleotide binding domain.

    PubMed

    Kothandan, Gugan; Gadhe, Changdev G; Madhavan, Thirumurthy; Choi, Cheol Hee; Cho, Seung Joo

    2011-09-01

    In order to explore the interactions between flavones and P-gp, in silico methodologies such as docking and 3D-QSAR were performed. CoMFA and CoMSIA analyses were done using ligand based and receptor guided alignment schemes. Validation statistics include leave-one-out cross-validated R(2) (q(2)), internal prediction parameter by progressive scrambling (Q(*2)), external prediction with test set. They show that models derived from this study are quite robust. Ligand based CoMFA (q(2) = 0.747, Q(*2) = 0.639, r(pred)(2)=0.802) and CoMSIA model (q(2) = 0.810, Q(*2) = 0.676, r(pred)(2)=0.785) were developed using atom by atom matching. Receptor guided CoMFA (q(2) = 0.712, Q(*2) = 0.497, r(pred)(2) = 0.841) and for CoMSIA (q(2) = 0.805, Q(*2) = 0.589, r(pred)(2) = 0.937) models were developed by docking of highly active flavone into the proposed NBD (nucleotide binding domain) of P-gp. The 3D-QSAR models generated here predicted that hydrophobic and steric parameters are important for activity toward P-gp. Our studies indicate the important amino acid in NBD crucial for binding in accordance with the previous results. This site forms a hydrophobic site. Since flavonoids have potential without toxicity, we propose to inspect this hydrophobic site including Asn1043 and Asp1049 should be considered for future inhibitor design. PMID:21723648

  6. Helicopter Flight Test of a Compact, Real-Time 3-D Flash Lidar for Imaging Hazardous Terrain During Planetary Landing

    NASA Technical Reports Server (NTRS)

    Roback, VIncent E.; Amzajerdian, Farzin; Brewster, Paul F.; Barnes, Bruce W.; Kempton, Kevin S.; Reisse, Robert A.; Bulyshev, Alexander E.

    2013-01-01

    A second generation, compact, real-time, air-cooled 3-D imaging Flash Lidar sensor system, developed from a number of cutting-edge components from industry and NASA, is lab characterized and helicopter flight tested under the Autonomous Precision Landing and Hazard Detection and Avoidance Technology (ALHAT) project. The ALHAT project is seeking to develop a guidance, navigation, and control (GN&C) and sensing system based on lidar technology capable of enabling safe, precise crewed or robotic landings in challenging terrain on planetary bodies under any ambient lighting conditions. The Flash Lidar incorporates a 3-D imaging video camera based on Indium-Gallium-Arsenide Avalanche Photo Diode and novel micro-electronic technology for a 128 x 128 pixel array operating at a video rate of 20 Hz, a high pulse-energy 1.06 µm Neodymium-doped: Yttrium Aluminum Garnet (Nd:YAG) laser, a remote laser safety termination system, high performance transmitter and receiver optics with one and five degrees field-of-view (FOV), enhanced onboard thermal control, as well as a compact and self-contained suite of support electronics housed in a single box and built around a PC-104 architecture to enable autonomous operations. The Flash Lidar was developed and then characterized at two NASA-Langley Research Center (LaRC) outdoor laser test range facilities both statically and dynamically, integrated with other ALHAT GN&C subsystems from partner organizations, and installed onto a Bell UH-1H Iroquois "Huey" helicopter at LaRC. The integrated system was flight tested at the NASA-Kennedy Space Center (KSC) on simulated lunar approach to a custom hazard field consisting of rocks, craters, hazardous slopes, and safe-sites near the Shuttle Landing Facility runway starting at slant ranges of 750 m. In order to evaluate different methods of achieving hazard detection, the lidar, in conjunction with the ALHAT hazard detection and GN&C system, operates in both a narrow 1deg FOV raster

  7. Progress in the Simulation of Steady and Time-Dependent Flows with 3D Parallel Unstructured Cartesian Methods

    NASA Technical Reports Server (NTRS)

    Aftosmis, M. J.; Berger, M. J.; Murman, S. M.; Kwak, Dochan (Technical Monitor)

    2002-01-01

    The proposed paper will present recent extensions in the development of an efficient Euler solver for adaptively-refined Cartesian meshes with embedded boundaries. The paper will focus on extensions of the basic method to include solution adaptation, time-dependent flow simulation, and arbitrary rigid domain motion. The parallel multilevel method makes use of on-the-fly parallel domain decomposition to achieve extremely good scalability on large numbers of processors, and is coupled with an automatic coarse mesh generation algorithm for efficient processing by a multigrid smoother. Numerical results are presented demonstrating parallel speed-ups of up to 435 on 512 processors. Solution-based adaptation may be keyed off truncation error estimates using tau-extrapolation or a variety of feature detection based refinement parameters. The multigrid method is extended to for time-dependent flows through the use of a dual-time approach. The extension to rigid domain motion uses an Arbitrary Lagrangian-Eulerlarian (ALE) formulation, and results will be presented for a variety of two- and three-dimensional example problems with both simple and complex geometry.

  8. Soil-plant-atmosphere water balance via time-lapse 3D Electrical Resistivity Tomography and Eddy covariance measurements

    NASA Astrophysics Data System (ADS)

    Boaga, J.; Consoli, S.; Papa, R.; Cassiani, G.

    2013-12-01

    The understanding of mass and energy exchanges between soil, plants and atmosphere (SPA) is a key component for the characterization of the critical zone, housing a number of important mechanisms controlling hydrology, biota and climate. This understanding requires reliable methods for the quantification of these mass and energy exchanges encompassing possibly all three major components, i.e. soil, plants and atmosphere. In this work we present an attempt to characterize jointly the soil state changes and the energy and mass fluxes above a heterogeneous canopy, both mediated by the plant activity from roots to foliage. The experiments have been conducted within an orange orchard located in Eastern Sicily (Italy), characterized by the typical Mediterranean semi-arid climate. The subsoil dynamics, particularly influenced by irrigation and root uptake, has been characterized using a time-lapse non-invasive 3D micro-electrical tomography (ERT) setup. We designed, built and installed a 3D electrical tomography apparatus consisting of 48 buried electrodes on 4 instrumented micro boreholes plus 24 mini-electrodes on the surface spaced 0.1 m on a square grid. During the monitoring, we collected repeated ERT and TDR soil moisture measurements, as well as laboratory characterization of the soil electrical properties as a function of moisture content and pore water electrical conductivity. The results demonstrate that 3D micro-ERT is capable of characterizing subsoil conditions and monitoring root zone activities, especially in terms of root zone suction regions. In terms of energy and mass fluxes, we used the Eddy Covariance (EC) technique to directly measure both the sensible and latent heat fluxes exchanged between the plant-atmosphere continuum. The EC method was integrated with the surface energy balance of the SPA system. The joint availability of state changes and fluxes allows for a quantitative analysis of mass balance in the soil-plant-atmosphere system. The

  9. Time-domain multiple-quantum NMR

    SciTech Connect

    Weitekamp, D.P.

    1982-11-01

    The development of time-domain multiple-quantum nuclear magnetic resonance is reviewed through mid 1982 and some prospects for future development are indicated. Particular attention is given to the problem of obtaining resolved, interpretable, many-quantum spectra for anisotropic magnetically isolated systems of coupled spins. New results are presented on a number of topics including the optimization of multiple-quantum-line intensities, analysis of noise in two-dimensional spectroscopy, and the use of order-selective excitation for cross polarization between nuclear-spin species.

  10. Architectures for Time-domain Astronomy

    NASA Astrophysics Data System (ADS)

    Seaman, R.; Allan, A.; Pierfederici, F.; Williams, R.

    2009-09-01

    Wonder at the changing sky predates recorded history. Empirical studies of time-varying celestial phenomena date back to Galileo and Tycho. Telegrams conveying news of transient and recurrent events have been key astronomical infrastructure since the nineteenth century. Recent micro-lensing, supernova and gamma-ray burst studies have lead to a succession of exciting discoveries, but massive new time-domain surveys will soon overwhelm our nineteenth century transient response technologies. Meeting this challenge demands new autonomous architectures for astronomy. These Architectures should reach from proposing new research, through experimental design and the scheduling of telescope operations, to the archiving and pipeline-processing of data to discover new transients, to the publishing of these events, through automated follow-up via robotic and ToO assets, and to the display and analysis of observational results. All will lead to adaptive adjustment of time-domain investigations. The IVOA VOEvent protocol provides an engine for purpose-built astronomical architectures.

  11. An assessment of the 3D geometric surrogacy of shock timing diagnostic techniques for tuning experiments on the NIF

    NASA Astrophysics Data System (ADS)

    Robey, H. F.; Munro, D. H.; Spears, B. K.; Marinak, M. M.; Jones, O. S.; Patel, M. V.; Haan, S. W.; Salmonson, J. D.; Landen, O. L.; Boehly, T. R.; Nikroo, A.

    2008-05-01

    Ignition capsule implosions planned for the National Ignition Facility (NIF) require a pulse shape with a carefully designed series of four steps, which launch a corresponding series of shocks through the ablator and DT ice shell. The relative timing of these shocks is critical for maintaining the DT fuel on a low adiabat. The current NIF specification requires that the timing of all four shocks be tuned to an accuracy of <= +/- 100ps. To meet these stringent requirements, dedicated tuning experiments are being planned to measure and adjust the shock timing on NIF. These tuning experiments will be performed in a modified hohlraum geometry, where a re-entrant Au cone is added to the standard NIF hohlraum to provide optical diagnostic (VISAR and SOP) access to the shocks as they break out of the ablator. This modified geometry is referred to as the 'keyhole' hohlraum and introduces a geometric difference between these tuning-experiments and the full ignition geometry. In order to assess the surrogacy of this modified geometry, 3D simulations using HYDRA [1] have been performed. The results from simulations of a quarter of the target geometry are presented. Comparisons of the hohlraum drive conditions and the resulting effect on the shock timing in the keyhole hohlraum are compared with the corresponding results for the standard ignition hohlraum.

  12. High-performance parallel solver for 3D time-dependent Schrodinger equation for large-scale nanosystems

    NASA Astrophysics Data System (ADS)

    Gainullin, I. K.; Sonkin, M. A.

    2015-03-01

    A parallelized three-dimensional (3D) time-dependent Schrodinger equation (TDSE) solver for one-electron systems is presented in this paper. The TDSE Solver is based on the finite-difference method (FDM) in Cartesian coordinates and uses a simple and explicit leap-frog numerical scheme. The simplicity of the numerical method provides very efficient parallelization and high performance of calculations using Graphics Processing Units (GPUs). For example, calculation of 106 time-steps on the 1000ṡ1000ṡ1000 numerical grid (109 points) takes only 16 hours on 16 Tesla M2090 GPUs. The TDSE Solver demonstrates scalability (parallel efficiency) close to 100% with some limitations on the problem size. The TDSE Solver is validated by calculation of energy eigenstates of the hydrogen atom (13.55 eV) and affinity level of H- ion (0.75 eV). The comparison with other TDSE solvers shows that a GPU-based TDSE Solver is 3 times faster for the problems of the same size and with the same cost of computational resources. The usage of a non-regular Cartesian grid or problem-specific non-Cartesian coordinates increases this benefit up to 10 times. The TDSE Solver was applied to the calculation of the resonant charge transfer (RCT) in nanosystems, including several related physical problems, such as electron capture during H+-H0 collision and electron tunneling between H- ion and thin metallic island film.

  13. Modular 3-D Transport model

    EPA Science Inventory

    MT3D was first developed by Chunmiao Zheng in 1990 at S.S. Papadopulos & Associates, Inc. with partial support from the U.S. Environmental Protection Agency (USEPA). Starting in 1990, MT3D was released as a pubic domain code from the USEPA. Commercial versions with enhanced capab...

  14. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    NASA Astrophysics Data System (ADS)

    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).

  15. Time-stepping stability of continuous and discontinuous finite-element methods for 3-D wave propagation

    NASA Astrophysics Data System (ADS)

    Mulder, W. A.; Zhebel, E.; Minisini, S.

    2014-02-01

    We analyse the time-stepping stability for the 3-D acoustic wave equation, discretized on tetrahedral meshes. Two types of methods are considered: mass-lumped continuous finite elements and the symmetric interior-penalty discontinuous Galerkin method. Combining the spatial discretization with the leap-frog time-stepping scheme, which is second-order accurate and conditionally stable, leads to a fully explicit scheme. We provide estimates of its stability limit for simple cases, namely, the reference element with Neumann boundary conditions, its distorted version of arbitrary shape, the unit cube that can be partitioned into six tetrahedra with periodic boundary conditions and its distortions. The Courant-Friedrichs-Lewy stability limit contains an element diameter for which we considered different options. The one based on the sum of the eigenvalues of the spatial operator for the first-degree mass-lumped element gives the best results. It resembles the diameter of the inscribed sphere but is slightly easier to compute. The stability estimates show that the mass-lumped continuous and the discontinuous Galerkin finite elements of degree 2 have comparable stability conditions, whereas the mass-lumped elements of degree one and three allow for larger time steps.

  16. Medical applications of fast 3D cameras in real-time image-guided radiotherapy (IGRT) of cancer

    NASA Astrophysics Data System (ADS)

    Li, Shidong; Li, Tuotuo; Geng, Jason

    2013-03-01

    Dynamic volumetric medical imaging (4DMI) has reduced motion artifacts, increased early diagnosis of small mobile tumors, and improved target definition for treatment planning. High speed cameras for video, X-ray, or other forms of sequential imaging allow a live tracking of external or internal movement useful for real-time image-guided radiation therapy (IGRT). However, none of 4DMI can track real-time organ motion and no camera has correlated with 4DMI to show volumetric changes. With a brief review of various IGRT techniques, we propose a fast 3D camera for live-video stereovision, an automatic surface-motion identifier to classify body or respiratory motion, a mechanical model for synchronizing the external surface movement with the internal target displacement by combination use of the real-time stereovision and pre-treatment 4DMI, and dynamic multi-leaf collimation for adaptive aiming the moving target. Our preliminary results demonstrate that the technique is feasible and efficient in IGRT of mobile targets. A clinical trial has been initiated for validation of its spatial and temporal accuracies and dosimetric impact for intensity-modulated RT (IMRT), volumetric-modulated arc therapy (VMAT), and stereotactic body radiotherapy (SBRT) of any mobile tumors. The technique can be extended for surface-guided stereotactic needle insertion in biopsy of small lung nodules.

  17. A computational 3D model for reconstruction of neural stem cells in bright-field time-lapse microscopy

    NASA Astrophysics Data System (ADS)

    Degerman, J.; Winterfors, E.; Faijerson, J.; Gustavsson, T.

    2007-02-01

    This paper describes a computational model for image formation of in-vitro adult hippocampal progenitor (AHP) cells, in bright-field time-lapse microscopy. Although this microscopymodality barely generates sufficient contrast for imaging translucent cells, we show that by using a stack of defocused image slices it is possible to extract position and shape of spherically shaped specimens, such as the AHP cells. This inverse problem was solved by modeling the physical objects and image formation system, and using an iterative nonlinear optimization algorithm to minimize the difference between the reconstructed and measured image stack. By assuming that the position and shape of the cells do not change significantly between two time instances, we can optimize these parameters using the previous time instance in a Bayesian estimation approach. The 3D reconstruction algorithm settings, such as focal sampling distance, and PSF, were calibrated using latex spheres of known size and refractive index. By using the residual between reconstructed and measured image intensities, we computed a peak signal-to-noise ratio (PSNR) to 28 dB for the sphere stack. A biological specimen analysis was done using an AHP cell, where reconstruction PSNR was 28 dB as well. The cell was immuno-histochemically stained and scanned in a confocal microscope, in order to compare our cell model to a ground truth. After convergence the modelled cell volume had an error of less than one percent.

  18. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys

    PubMed Central

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    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). PMID:27302087

  19. Real-time microstructure imaging by Laue microdiffraction: A sample application in laser 3D printed Ni-based superalloys.

    PubMed

    Zhou, Guangni; Zhu, Wenxin; Shen, Hao; Li, Yao; Zhang, Anfeng; Tamura, Nobumichi; Chen, Kai

    2016-01-01

    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). PMID:27302087

  20. Design and implementation of an efficient finite-difference, time-domain computer code for large problems

    SciTech Connect

    White, W.T. III; Taflove, A.; Stringer, J.C.; Kluge, R.F.

    1986-12-01

    As computers get larger and faster, demands upon electromagnetics codes increase. Ever larger volumes of space must be represented with increasingly more accuracy and detail. This requires continually more efficient EM codes. To meet present and future needs in DOE and DOD, we are developing FDTD3D, a three-dimensional finite-difference, time-domain EM solver. When complete, the code will efficiently solve problems with tens of millions of unknowns. It already operates faster than any other 3D, time-domain EM code, and we are using it to model linear coupling to a generic missile section. At Lawrence Livermore National Laboratory (LLNL), we anticipate the ultimate need for such a code if we are to model EM threats to objects such as airplanes or missiles. This article describes the design and implementation of FDTD3D. The first section, ''Design of FDTD3D,'' contains a brief summary of other 3D time-domain EM codes at LLNL followed by a description of the efficiency of FDTD3D. The second section, ''Implementation of FDTD3D,'' discusses recent work and future plans.

  1. Radiosity diffusion model in 3D

    NASA Astrophysics Data System (ADS)

    Riley, Jason D.; Arridge, Simon R.; Chrysanthou, Yiorgos; Dehghani, Hamid; Hillman, Elizabeth M. C.; Schweiger, Martin

    2001-11-01

    We present the Radiosity-Diffusion model in three dimensions(3D), as an extension to previous work in 2D. It is a method for handling non-scattering spaces in optically participating media. We present the extension of the model to 3D including an extension to the model to cope with increased complexity of the 3D domain. We show that in 3D more careful consideration must be given to the issues of meshing and visibility to model the transport of light within reasonable computational bounds. We demonstrate the model to be comparable to Monte-Carlo simulations for selected geometries, and show preliminary results of comparisons to measured time-resolved data acquired on resin phantoms.

  2. Longitudinal, 3D Imaging of Collagen Remodeling in Murine Hypertrophic Scars In Vivo using Polarization-sensitive Optical Frequency Domain Imaging

    PubMed Central

    Lo, William C. Y.; Villiger, Martin; Golberg, Alexander; Broelsch, G. Felix; Khan, Saiqa; Lian, Christine G.; Austen, William G.; Yarmush, Martin; Bouma, Brett E.

    2016-01-01

    Hypertrophic scars (HTS), frequently seen after traumatic injuries and surgery, remain a major clinical challenge due to the limited success of existing therapies. A significant obstacle to understanding HTS etiology is the lack of tools to monitor scar remodeling longitudinally and non-invasively. We present an in vivo, label-free technique using polarization-sensitive optical frequency domain imaging (PS-OFDI) for the 3D, longitudinal assessment of collagen remodeling in murine HTS. In this study, HTS was induced with a mechanical tension device for 4 to 10 days on incisional wounds and imaged up to one month after device removal; an excisional HTS model was also imaged at 6 months after injury to investigate deeper and more mature scars. We showed that local retardation (LR) and degree of polarization (DOP) provide a robust signature for HTS. Compared to normal skin with heterogeneous LR and low DOP, HTS was characterized by an initially low LR, which increased as collagen fibers remodeled, and a persistently high DOP. This study demonstrates that PS-OFDI offers a powerful tool to gain significant biological insights into HTS remodeling by enabling longitudinal assessment of collagen in vivo, which is critical to elucidating HTS etiology and developing more effective HTS therapies. PMID:26763427

  3. Quantitative real-time detection of carcinoembryonic antigen (CEA) from pancreatic cyst fluid using 3-D surface molecular imprinting.

    PubMed

    Yu, Yingjie; Zhang, Qi; Buscaglia, Jonathan; Chang, Chung-Chueh; Liu, Ying; Yang, Zhenhua; Guo, Yichen; Wang, Yantian; Levon, Kalle; Rafailovich, Miriam

    2016-07-21

    In this study, a sensitive, yet robust, biosensing system with real-time electrochemical readout was developed. The biosensor system was applied to the detection of carcinoembryonic antigen (CEA), which is a common marker for many cancers such as pancreatic, breast, and colon cancer. Real time detection of CEA during a medical procedure can be used to make critical decisions regarding further surgical intervention. CEA was templated on gold surface (RMS roughness ∼3-4 nm) coated with a hydrophilic self-assembled monolayer (SAM) on the working electrode of an open circuit potentiometric network. The subsequent removal of template CEA makes the biosensor capable of CEA detection based on its specific structure and conformation. The molecular imprinting (MI) biosensor was further calibrated using the potentiometric responses in solutions with known CEA concentrations and a detection limit of 0.5 ng ml(-1) was achieved. Potentiometric sensing was then applied to pancreatic cyst fluid samples obtained from 18 patients when the cyst fluid was also evaluated using ELISA in a certified pathology laboratory. Excellent agreement was obtained between the quantitation of CEA obtained by both the ELISA and MI biosensor detection for CEA. A 3-D MI model, using the natural rms roughness of PVD gold layers, is presented to explain the high degree of sensitivity and linearity observed in those experiments. PMID:27193921

  4. GE simplified boiling water reactor stability analysis in time domain

    NASA Astrophysics Data System (ADS)

    Lu, Shanlai

    1997-12-01

    General Electric Simplified Boiling Water Reactor (SBWR) was designed as a next generation light water reactor. It uses natural circulation to remove the heat from the reactor core. Because of this unique in-vessel circulation feature, SBWR is expected to exhibit different stability behaviors. The main emphasis of this thesis is to study the SBWR stability behavior in the time domain. The best-estimate BWR accident/transient analysis computer code, TRAC-BF1, is employed to analyze the SBWR stability behavior. A detailed TRAC-BF1 SBWR model has been developed, which has the capability to model the in-vessel natural circulation and the reactor core kinetics. The model is used to simulate three slow depressurization processes. The simulation results show that the reactor is stable under low pressure and nominal downcomer water level conditions. However, when the downcomer water level is raised to about 19.2 m above the bottom of the reactor vessel, an unstable power oscillation is observed. The identified power oscillation is further analyzed using TRAC-BF1 1-D kinetics and the new TRAC-BF1 3-D kinetics code developed in this thesis. The effects of different time step sizes and vessel model nodalizations are examined. It is found that the power oscillation is in-phase and has a frequency of 0.3 HZ. In order to further explore the physical instabilty initiation mechanisms, a simplified dynamic model consisting of six simple differential equations is developed. The simplified model is able to predict the dominant physical phenomenon identified by the TRAC-BF1 analysis. The results indicate that the system instability is possibly caused by the steam separator hydro-static head oscillation under the high water level condition. In order to explore the higher order spacial effect of power oscillation, a 3-D reactor core kinetics code is coupled with the TRAC-BF1 computer code in the PVM parallel processing environment. A new coupling scheme and a multiple time step marching

  5. Papyrus imaging with terahertz time domain spectroscopy

    NASA Astrophysics Data System (ADS)

    Labaune, J.; Jackson, J. B.; Pagès-Camagna, S.; Duling, I. N.; Menu, M.; Mourou, G. A.

    2010-09-01

    Terahertz time domain spectroscopic imaging (THz-TDSI) is a non-ionizing, non-contact and non-destructive measurement technique that has been recently utilized to study cultural heritage artifacts. We will present this technique and the results of non-contact measurements of papyrus texts, including images of hidden papyri. Inks for modern papyrus specimens were prepared using the historical binder, Arabic gum, and two common pigments used to write ancient texts, carbon black and red ochre. The samples were scanned in reflection at normal incidence with a pulse with a spectral range between 0.1 and 1.5 THz. Temporal analysis of the signals provides the depths of the layers, and their frequency spectra give information about the inks.

  6. Gravitational Waves and Time Domain Astronomy

    NASA Technical Reports Server (NTRS)

    Centrella, Joan; Nissanke, Samaya; Williams, Roy

    2012-01-01

    The gravitational wave window onto the universe will open in roughly five years, when Advanced LIGO and Virgo achieve the first detections of high frequency gravitational waves, most likely coming from compact binary mergers. Electromagnetic follow-up of these triggers, using radio, optical, and high energy telescopes, promises exciting opportunities in multi-messenger time domain astronomy. In the decade, space-based observations of low frequency gravitational waves from massive black hole mergers, and their electromagnetic counterparts, will open up further vistas for discovery. This two-part workshop featured brief presentations and stimulating discussions on the challenges and opportunities presented by gravitational wave astronomy. Highlights from the workshop, with the emphasis on strategies for electromagnetic follow-up, are presented in this report.

  7. Architecture of web services in the enhancement of real-time 3D video virtualization in cloud environment

    NASA Astrophysics Data System (ADS)

    Bada, Adedayo; Wang, Qi; Alcaraz-Calero, Jose M.; Grecos, Christos

    2016-04-01

    This paper proposes a new approach to improving the application of 3D video rendering and streaming by jointly exploring and optimizing both cloud-based virtualization and web-based delivery. The proposed web service architecture firstly establishes a software virtualization layer based on QEMU (Quick Emulator), an open-source virtualization software that has been able to virtualize system components except for 3D rendering, which is still in its infancy. The architecture then explores the cloud environment to boost the speed of the rendering at the QEMU software virtualization layer. The capabilities and inherent limitations of Virgil 3D, which is one of the most advanced 3D virtual Graphics Processing Unit (GPU) available, are analyzed through benchmarking experiments and integrated into the architecture to further speed up the rendering. Experimental results are reported and analyzed to demonstrate the benefits of the proposed approach.

  8. 3D imaging of cone photoreceptors over extended time periods using optical coherence tomography with adaptive optics

    NASA Astrophysics Data System (ADS)

    Kocaoglu, Omer P.; Lee, Sangyeol; Jonnal, Ravi S.; Wang, Qiang; Herde, Ashley E.; Besecker, Jason; Gao, Weihua; Miller, Donald T.

    2011-03-01

    Optical coherence tomography with adaptive optics (AO-OCT) is a highly sensitive, noninvasive method for 3D imaging of the microscopic retina. The purpose of this study is to advance AO-OCT technology by enabling repeated imaging of cone photoreceptors over extended periods of time (days). This sort of longitudinal imaging permits monitoring of 3D cone dynamics in both normal and diseased eyes, in particular the physiological processes of disc renewal and phagocytosis, which are disrupted by retinal diseases such as age related macular degeneration and retinitis pigmentosa. For this study, the existing AO-OCT system at Indiana underwent several major hardware and software improvements to optimize system performance for 4D cone imaging. First, ultrahigh speed imaging was realized using a Basler Sprint camera. Second, a light source with adjustable spectrum was realized by integration of an Integral laser (Femto Lasers, λc=800nm, ▵λ=160nm) and spectral filters in the source arm. For cone imaging, we used a bandpass filter with λc=809nm and ▵λ=81nm (2.6 μm nominal axial resolution in tissue, and 167 KHz A-line rate using 1,408 px), which reduced the impact of eye motion compared to previous AO-OCT implementations. Third, eye motion artifacts were further reduced by custom ImageJ plugins that registered (axially and laterally) the volume videos. In two subjects, cone photoreceptors were imaged and tracked over a ten day period and their reflectance and outer segment (OS) lengths measured. High-speed imaging and image registration/dewarping were found to reduce eye motion to a fraction of a cone width (1 μm root mean square). The pattern of reflections in the cones was found to change dramatically and occurred on a spatial scale well below the resolution of clinical instruments. Normalized reflectance of connecting cilia (CC) and OS posterior tip (PT) of an exemplary cone was 54+/-4, 47+/-4, 48+/-6, 50+/-5, 56+/-1% and 46+/-4, 53+/-4, 52+/-6, 50+/-5, 44

  9. A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage

    PubMed Central

    Faure, Emmanuel; Savy, Thierry; Rizzi, Barbara; Melani, Camilo; Stašová, Olga; Fabrèges, Dimitri; Špir, Róbert; Hammons, Mark; Čúnderlík, Róbert; Recher, Gaëlle; Lombardot, Benoît; Duloquin, Louise; Colin, Ingrid; Kollár, Jozef; Desnoulez, Sophie; Affaticati, Pierre; Maury, Benoît; Boyreau, Adeline; Nief, Jean-Yves; Calvat, Pascal; Vernier, Philippe; Frain, Monique; Lutfalla, Georges; Kergosien, Yannick; Suret, Pierre; Remešíková, Mariana; Doursat, René; Sarti, Alessandro; Mikula, Karol; Peyriéras, Nadine; Bourgine, Paul

    2016-01-01

    The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology. PMID:26912388

  10. A workflow to process 3D+time microscopy images of developing organisms and reconstruct their cell lineage.

    PubMed

    Faure, Emmanuel; Savy, Thierry; Rizzi, Barbara; Melani, Camilo; Stašová, Olga; Fabrèges, Dimitri; Špir, Róbert; Hammons, Mark; Čúnderlík, Róbert; Recher, Gaëlle; Lombardot, Benoît; Duloquin, Louise; Colin, Ingrid; Kollár, Jozef; Desnoulez, Sophie; Affaticati, Pierre; Maury, Benoît; Boyreau, Adeline; Nief, Jean-Yves; Calvat, Pascal; Vernier, Philippe; Frain, Monique; Lutfalla, Georges; Kergosien, Yannick; Suret, Pierre; Remešíková, Mariana; Doursat, René; Sarti, Alessandro; Mikula, Karol; Peyriéras, Nadine; Bourgine, Paul

    2016-01-01

    The quantitative and systematic analysis of embryonic cell dynamics from in vivo 3D+time image data sets is a major challenge at the forefront of developmental biology. Despite recent breakthroughs in the microscopy imaging of living systems, producing an accurate cell lineage tree for any developing organism remains a difficult task. We present here the BioEmergences workflow integrating all reconstruction steps from image acquisition and processing to the interactive visualization of reconstructed data. Original mathematical methods and algorithms underlie image filtering, nucleus centre detection, nucleus and membrane segmentation, and cell tracking. They are demonstrated on zebrafish, ascidian and sea urchin embryos with stained nuclei and membranes. Subsequent validation and annotations are carried out using Mov-IT, a custom-made graphical interface. Compared with eight other software tools, our workflow achieved the best lineage score. Delivered in standalone or web service mode, BioEmergences and Mov-IT offer a unique set of tools for in silico experimental embryology. PMID:26912388

  11. Computational hologram synthesis and representation on spatial light modulators for real-time 3D holographic imaging

    NASA Astrophysics Data System (ADS)

    Reichelt, Stephan; Leister, Norbert

    2013-02-01

    In dynamic computer-generated holography that utilizes spatial light modulators, both hologram synthesis and hologram representation are essential in terms of fast computation and high reconstruction quality. For hologram synthesis, i.e. the computation step, Fresnel transform based or point-source based raytracing methods can be applied. In the encoding step, the complex wave-field has to be optimally represented by the SLM with its given modulation capability. For proper hologram reconstruction that implies a simultaneous and independent amplitude and phase modulation of the input wave-field by the SLM. In this paper, we discuss full complex hologram representation methods on SLMs by considering inherent SLM parameter such as modulation type and bit depth on their reconstruction performance such as diffraction efficiency and SNR. We review the three implementation schemes of Burckhardt amplitude-only representation, phase-only macro-pixel representation, and two-phase interference representation. Besides the optical performance we address their hardware complexity and required computational load. Finally, we experimentally demonstrate holographic reconstructions of different representation schemes as obtained by functional prototypes utilizing SeeReal's viewing-window holographic display technology. The proposed hardware implementations enable a fast encoding of complex-valued hologram data and thus will pave the way for commercial real-time holographic 3D imaging in the near future.

  12. Real-time 3D curved needle segmentation using combined B-mode and power Doppler ultrasound.

    PubMed

    Greer, Joseph D; Adebar, Troy K; Hwang, Gloria L; Okamura, Allison M

    2014-01-01

    This paper presents a real-time segmentation method for curved needles in biological tissue based on analysis of B-mode and power Doppler images from a tracked 2D ultrasound transducer. Mechanical vibration induced by an external voice coil results in a Doppler response along the needle shaft, which is centered around the needle section in the ultrasound image. First, B-mode image analysis is performed within regions of interest indicated by the Doppler response to create a segmentation of the needle section in the ultrasound image. Next, each needle section is decomposed into a sequence of points and transformed into a global coordinate system using the tracked transducer pose. Finally, the 3D shape is reconstructed from these points. The results of this method differ from manual segmentation by 0.71 ± 0.55 mm in needle tip location and 0.38 ± 0.27 mm along the needle shaft. This method is also fast, taking 5-10 ms to run on a standard PC, and is particularly advantageous in robotic needle steering, which involves thin, curved needles with poor echogenicity. PMID:25485402

  13. Short and long time effects of low temperature Plasma Activated Media on 3D multicellular tumor spheroids

    PubMed Central

    Judée, Florian; Fongia, Céline; Ducommun, Bernard; Yousfi, Mohammed; Lobjois, Valérie; Merbahi, Nofel

    2016-01-01

    This work investigates the regionalized antiproliferative effects of plasma-activated medium (PAM) on colon adenocarcinoma multicellular tumor spheroid (MCTS), a model that mimics 3D organization and regionalization of a microtumor region. PAM was generated by dielectric barrier plasma jet setup crossed by helium carrier gas. MCTS were transferred in PAM at various times after plasma exposure up to 48 hours and effect on MCTS growth and DNA damage were evaluated. We report the impact of plasma exposure duration and delay before transfer on MCTS growth and DNA damage. Local accumulation of DNA damage revealed by histone H2AX phosphorylation is observed on outermost layers and is dependent on plasma exposure. DNA damage is completely reverted by catalase addition indicating that H2O2 plays major role in observed genotoxic effect while growth inhibitory effect is maintained suggesting that it is due to others reactive species. SOD and D-mannitol scavengers also reduced DNA damage by 30% indicating that and OH* are involved in H2O2 formation. Finally, PAM is able to retain its cytotoxic and genotoxic activity upon storage at +4 °C or −80 °C. These results suggest that plasma activated media may be a promising new antitumor strategy for colorectal cancer tumors. PMID:26898904

  14. Short and long time effects of low temperature Plasma Activated Media on 3D multicellular tumor spheroids

    NASA Astrophysics Data System (ADS)

    Judée, Florian; Fongia, Céline; Ducommun, Bernard; Yousfi, Mohammed; Lobjois, Valérie; Merbahi, Nofel

    2016-02-01

    This work investigates the regionalized antiproliferative effects of plasma-activated medium (PAM) on colon adenocarcinoma multicellular tumor spheroid (MCTS), a model that mimics 3D organization and regionalization of a microtumor region. PAM was generated by dielectric barrier plasma jet setup crossed by helium carrier gas. MCTS were transferred in PAM at various times after plasma exposure up to 48 hours and effect on MCTS growth and DNA damage were evaluated. We report the impact of plasma exposure duration and delay before transfer on MCTS growth and DNA damage. Local accumulation of DNA damage revealed by histone H2AX phosphorylation is observed on outermost layers and is dependent on plasma exposure. DNA damage is completely reverted by catalase addition indicating that H2O2 plays major role in observed genotoxic effect while growth inhibitory effect is maintained suggesting that it is due to others reactive species. SOD and D-mannitol scavengers also reduced DNA damage by 30% indicating that and OH* are involved in H2O2 formation. Finally, PAM is able to retain its cytotoxic and genotoxic activity upon storage at +4 °C or -80 °C. These results suggest that plasma activated media may be a promising new antitumor strategy for colorectal cancer tumors.

  15. Single Molecule 3D Orientation in Time and Space: A 6D Dynamic Study on Fluorescently Labeled Lipid Membranes.

    PubMed

    Börner, Richard; Ehrlich, Nicky; Hohlbein, Johannes; Hübner, Christian G

    2016-05-01

    Interactions between single molecules profoundly depend on their mutual three-dimensional orientation. Recently, we demonstrated a technique that allows for orientation determination of single dipole emitters using a polarization-resolved distribution of fluorescence into several detection channels. As the method is based on the detection of single photons, it additionally allows for performing fluorescence correlation spectroscopy (FCS) as well as dynamical anisotropy measurements thereby providing access to fast orientational dynamics down to the nanosecond time scale. The 3D orientation is particularly interesting in non-isotropic environments such as lipid membranes, which are of great importance in biology. We used giant unilamellar vesicles (GUVs) labeled with fluorescent dyes down to a single molecule concentration as a model system for both, assessing the robustness of the orientation determination at different timescales and quantifying the associated errors. The vesicles provide a well-defined spherical surface, such that the use of fluorescent lipid dyes (DiO) allows to establish a a wide range of dipole orientations experimentally. To complement our experimental data, we performed Monte Carlo simulations of the rotational dynamics of dipoles incorporated into lipid membranes. Our study offers a comprehensive view on the dye orientation behavior in a lipid membrane with high spatiotemporal resolution representing a six-dimensional fluorescence detection approach. PMID:26972111

  16. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem

    PubMed Central

    McClay, Wilbert A.; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T.; Nagarajan, Srikantan S.

    2015-01-01

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user’s intent for specific keyboard strikes or mouse button presses. The BCI’s data analytics of a subject’s MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432

  17. Exploration of the potential of liquid scintillators for real-time 3D dosimetry of intensity modulated proton beams

    PubMed Central

    Beddar, Sam; Archambault, Louis; Sahoo, Narayan; Poenisch, Falk; Chen, George T.; Gillin, Michael T.; Mohan, Radhe

    2009-01-01

    In this study, the authors investigated the feasibility of using a 3D liquid scintillator (LS) detector system for the verification and characterization of proton beams in real time for intensity and energy-modulated proton therapy. A plastic tank filled with liquid scintillator was irradiated with pristine proton Bragg peaks. Scintillation light produced during the irradiation was measured with a CCD camera. Acquisition rates of 20 and 10 frames per second (fps) were used to image consecutive frame sequences. These measurements were then compared to ion chamber measurements and Monte Carlo simulations. The light distribution measured from the images acquired at rates of 20 and 10 fps have standard deviations of 1.1% and 0.7%, respectively, in the plateau region of the Bragg curve. Differences were seen between the raw LS signal and the ion chamber due to the quenching effects of the LS and due to the optical properties of the imaging system. The authors showed that this effect can be accounted for and corrected by Monte Carlo simulations. The liquid scintillator detector system has a good potential for performing fast proton beam verification and characterization. PMID:19544791

  18. Progress in Ring Array Transducers for Real-Time 3D Ultrasound Guidance of Cardiac Interventional Devices

    PubMed Central

    Light, Edward D.; Lieu, Victor; Suhocki, Paul; Wolf, Patrick D.; Smith, Stephen W.

    2012-01-01

    As a treatment for aortic stenosis, several companies have recently introduced prosthetic heart valves designed to be deployed through a catheter using an intravenous or trans-apical approach. This procedure can either take the place of open heart surgery with some of the devices, or delay it with others. Real-time 3D ultrasound could enable continuous monitoring of these structures before, during and after deployment. We have developed a 2D ring array integrated with a 30 French catheter that is used for trans-apical prosthetic heart valve implantation. The transducer array was built using three 46 cm long flex circuits from MicroConnex (Snoqualmie, WA) which terminate in an interconnect that plugs directly into our system cable, thus no cable soldering is required. This transducer consists of 210 elements at .157 mm inter-element spacing and operates at 5 MHz. Average measured element bandwidth was 26% and average round-trip 50 Ohm insertion loss was -81.1 dB. The transducer were wrapped around the 1 cm diameter lumen of a heart valve deployment catheter. Prosthetic heart valve images were obtained in water tank studies. PMID:21842583

  19. VR-Planets : a 3D immersive application for real-time flythrough images of planetary surfaces

    NASA Astrophysics Data System (ADS)

    Civet, François; Le Mouélic, Stéphane

    2015-04-01

    During the last two decades, a fleet of planetary probes has acquired several hundred gigabytes of images of planetary surfaces. Mars has been particularly well covered thanks to the Mars Global Surveyor, Mars Express and Mars Reconnaissance Orbiter spacecrafts. HRSC, CTX, HiRISE instruments allowed the computation of Digital Elevation Models with a resolution from hundreds of meters up to 1 meter per pixel, and corresponding orthoimages with a resolution from few hundred of meters up to 25 centimeters per pixel. The integration of such huge data sets into a system allowing user-friendly manipulation either for scientific investigation or for public outreach can represent a real challenge. We are investigating how innovative tools can be used to freely fly over reconstructed landscapes in real time, using technologies derived from the game industry and virtual reality. We have developed an application based on a game engine, using planetary data, to immerse users in real martian landscapes. The user can freely navigate in each scene at full spatial resolution using a game controller. The actual rendering is compatible with several visualization devices such as 3D active screen, virtual reality headsets (Oculus Rift), and android devices.

  20. Short and long time effects of low temperature Plasma Activated Media on 3D multicellular tumor spheroids.

    PubMed

    Judée, Florian; Fongia, Céline; Ducommun, Bernard; Yousfi, Mohammed; Lobjois, Valérie; Merbahi, Nofel

    2016-01-01

    This work investigates the regionalized antiproliferative effects of plasma-activated medium (PAM) on colon adenocarcinoma multicellular tumor spheroid (MCTS), a model that mimics 3D organization and regionalization of a microtumor region. PAM was generated by dielectric barrier plasma jet setup crossed by helium carrier gas. MCTS were transferred in PAM at various times after plasma exposure up to 48 hours and effect on MCTS growth and DNA damage were evaluated. We report the impact of plasma exposure duration and delay before transfer on MCTS growth and DNA damage. Local accumulation of DNA damage revealed by histone H2AX phosphorylation is observed on outermost layers and is dependent on plasma exposure. DNA damage is completely reverted by catalase addition indicating that H2O2 plays major role in observed genotoxic effect while growth inhibitory effect is maintained suggesting that it is due to others reactive species. SOD and D-mannitol scavengers also reduced DNA damage by 30% indicating that O(2)(-)* and OH* are involved in H2O2 formation. Finally, PAM is able to retain its cytotoxic and genotoxic activity upon storage at +4 °C or -80 °C. These results suggest that plasma activated media may be a promising new antitumor strategy for colorectal cancer tumors. PMID:26898904

  1. Accuracy of a Mitral Valve Segmentation Method Using J-Splines for Real-Time 3D Echocardiography Data

    PubMed Central

    Siefert, Andrew W.; Icenogle, David A.; Rabbah, Jean-Pierre; Saikrishnan, Neelakantan; Rossignac, Jarek; Lerakis, Stamatios; Yoganathan, Ajit P.

    2013-01-01

    Patient-specific models of the heart’s mitral valve (MV) exhibit potential for surgical planning. While advances in 3D echocardiography (3DE) have provided adequate resolution to extract MV leaflet geometry, no study has quantitatively assessed the accuracy of their modeled leaflets versus a ground-truth standard for temporal frames beyond systolic closure or for differing valvular dysfunctions. The accuracy of a 3DE-based segmentation methodology based on J-splines was assessed for porcine MVs with known 4D leaflet coordinates within a pulsatile simulator during closure, peak closure, and opening for a control, prolapsed, and billowing MV model. For all time points, the mean distance error between the segmented models and ground-truth data were 0.40±0.32 mm, 0.52±0.51 mm, and 0.74±0.69 mm for the control, flail, and billowing models. For all models and temporal frames, 95% of the distance errors were below 1.64 mm. When applied to a patient data set, segmentation was able to confirm a regurgitant orifice and post-operative improvements in coaptation. This study provides an experimental platform for assessing the accuracy of an MV segmentation methodology at phases beyond systolic closure and for differing MV dysfunctions. Results demonstrate the accuracy of a MV segmentation methodology for the development of future surgical planning tools. PMID:23460042

  2. A Real-Time Magnetoencephalography Brain-Computer Interface Using Interactive 3D Visualization and the Hadoop Ecosystem.

    PubMed

    McClay, Wilbert A; Yadav, Nancy; Ozbek, Yusuf; Haas, Andy; Attias, Hagaii T; Nagarajan, Srikantan S

    2015-01-01

    Ecumenically, the fastest growing segment of Big Data is human biology-related data and the annual data creation is on the order of zetabytes. The implications are global across industries, of which the treatment of brain related illnesses and trauma could see the most significant and immediate effects. The next generation of health care IT and sensory devices are acquiring and storing massive amounts of patient related data. An innovative Brain-Computer Interface (BCI) for interactive 3D visualization is presented utilizing the Hadoop Ecosystem for data analysis and storage. The BCI is an implementation of Bayesian factor analysis algorithms that can distinguish distinct thought actions using magneto encephalographic (MEG) brain signals. We have collected data on five subjects yielding 90% positive performance in MEG mid- and post-movement activity. We describe a driver that substitutes the actions of the BCI as mouse button presses for real-time use in visual simulations. This process has been added into a flight visualization demonstration. By thinking left or right, the user experiences the aircraft turning in the chosen direction. The driver components of the BCI can be compiled into any software and substitute a user's intent for specific keyboard strikes or mouse button presses. The BCI's data analytics OPEN ACCESS Brain. Sci. 2015, 5 420 of a subject's MEG brainwaves and flight visualization performance are stored and analyzed using the Hadoop Ecosystem as a quick retrieval data warehouse. PMID:26437432

  3. Imaging Nuclear Waste Plumes at the Hanford Site using Large Domain 3D High Resolution Resistivity Methods and the New Parallel-Processing EarthImager3DCL Program

    NASA Astrophysics Data System (ADS)

    Greenwood, J.; Rucker, D.; Levitt, M.; Yang, X.; Lagmanson, M.

    2007-12-01

    High Resolution Resistivity data is currently used by hydroGEOPHYSICS, Inc to detect and characterize the distribution of suspected contaminant plumes beneath leaking tanks and disposal sites within the U.S. Department of Energy Hanford Site, in Eastern Washington State. The success of the characterization effort has led to resistivity data acquisition in extremely large survey areas exceeding 0.6 km2 and containing over 6,000 electrodes. Optimal data processing results are achieved by utilizing 105 data points within a single finite difference or finite element model domain. The large number of measurements and electrodes and high resolution of the modeling domain requires a model mesh of over 106 nodes. Existing commercially available resistivity inversion software could not support the domain size due to software and hardware limitations. hydroGEOPHYSICS, Inc teamed with Advanced Geosciences, Inc to advance the existing EarthImager3D inversion software to allow for parallel-processing and large memory support under a 64 bit operating system. The basis for the selection of EarthImager3D is demonstrated with a series of verification tests and benchmark comparisons using synthetic test models, field scale experiments and 6 months of intensive modeling using an array of multi-processor servers. The results of benchmark testing show equivalence to other industry standard inversion codes that perform the same function on significantly smaller domain models. hydroGEOPHYSICS, Inc included the use of 214 steel-cased monitoring wells as "long electrodes", 6000 surface electrodes and 8 buried point source electrodes. Advanced Geosciences, Inc. implemented a long electrode modeling function to support the Hanford Site well casing data. This utility is unique to commercial resistivity inversion software, and was evaluated through a series of laboratory and field scale tests using engineered subsurface plumes. The Hanford site is an ideal proving ground for these methods due

  4. Time-Domain Terahertz Computed Axial Tomography NDE System

    NASA Technical Reports Server (NTRS)

    Zimdars, David

    2012-01-01

    NASA has identified the need for advanced non-destructive evaluation (NDE) methods to characterize aging and durability in aircraft materials to improve the safety of the nation's airline fleet. 3D THz tomography can play a major role in detection and characterization of flaws and degradation in aircraft materials, including Kevlar-based composites and Kevlar and Zylon fabric covers for soft-shell fan containment where aging and durability issues are critical. A prototype computed tomography (CT) time-domain (TD) THz imaging system has been used to generate 3D images of several test objects including a TUFI tile (a thermal protection system tile used on the Space Shuttle and possibly the Orion or similar capsules). This TUFI tile had simulated impact damage that was located and the depth of damage determined. The CT motion control gan try was designed and constructed, and then integrated with a T-Ray 4000 control unit and motion controller to create a complete CT TD-THz imaging system prototype. A data collection software script was developed that takes multiple z-axis slices in sequence and saves the data for batch processing. The data collection software was integrated with the ability to batch process the slice data with the CT TD-THz image reconstruction software. The time required to take a single CT slice was decreased from six minutes to approximately one minute by replacing the 320 ps, 100-Hz waveform acquisition system with an 80 ps, 1,000-Hz waveform acquisition system. The TD-THZ computed tomography system was built from pre-existing commercial off-the-shelf subsystems. A CT motion control gantry was constructed from COTS components that can handle larger samples. The motion control gantry allows inspection of sample sizes of up to approximately one cubic foot (.0.03 cubic meters). The system reduced to practice a CT-TDTHz system incorporating a COTS 80- ps/l-kHz waveform scanner. The incorporation of this scanner in the system allows acquisition of 3D

  5. 3-D ion distribution and evolution in storm-time RC Retrieved from TWINS ENA by differential voxel CT technique

    NASA Astrophysics Data System (ADS)

    Ma, S.; Yan, W.; Xu, L.

    2013-12-01

    The quantitative retrieval of the 3-D spatial distribution of the parent energetic ions of ENA from a 2-D ENA image is a quite challenge task. The Two Wide-angle Imaging Neutral-atom Spectrometers (TWINS) mission of NASA is the first constellation to perform stereoscopic magnetospheric imaging of energetic neutral atoms (ENA) from a pair of spacecraft flying on two widely-separated Molniya orbits. TWINS provides a unique opportunity to retrieve the 3-D distribution of ions in the ring current (RC) by using a volumetric pixel (voxel) CT inversion method. In this study the voxel CT method is implemented for a series of differential ENA fluxes averaged over about 6 to 7 sweeps (corresponding to a time period of about 9 min.) at different energy levels ranging from 5 to 100 keV, obtained simultaneously by the two satellites during the main phase of a great magnetic storm with minimum Sym-H of -156 nT on 24-25 October 2011. The data were selected to span a period about 50 minutes during which a large substorm was undergoing its expansion phase first and then recovery. The ENA species of O and H are distinguished for some time-segments by analyzing the signals of pulse heights of second electrons emitted from the carbon foil and impacted on the MCP detector in the TWINS sensors. In order to eliminate the possible influence on retrieval induced by instrument bias error, a differential voxel CT technique is applied. The flux intensity of the ENAs' parent ions in the RC has been obtained as a function of energy, L value, MLT sector and latitude, along with their time evolution during the storm-time substorm expansion phase. Forward calculations proved the reliability of the retrieved results. It shows that the RC is highly asymmetric, with a major concentration in the midnight to dawn sector for equatorial latitudes. Halfway through the substorm expansion there occurred a large enhancement of equatorial ion flux at lower energy (5 keV) in the dusk sector, with narrow extent

  6. Quantification of Shunt Volume Through Ventricular Septal Defect by Real-Time 3-D Color Doppler Echocardiography: An in Vitro Study.

    PubMed

    Zhu, Meihua; Ashraf, Muhammad; Tam, Lydia; Streiff, Cole; Kimura, Sumito; Shimada, Eriko; Sahn, David J

    2016-05-01

    Quantification of shunt volume is important for ventricular septal defects (VSDs). The aim of the in vitro study described here was to test the feasibility of using real-time 3-D color Doppler echocardiography (RT3-D-CDE) to quantify shunt volume through a modeled VSD. Eight porcine heart phantoms with VSDs ranging in diameter from 3 to 25 mm were studied. Each phantom was passively driven at five different stroke volumes from 30 to 70 mL and two stroke rates, 60 and 120 strokes/min. RT3-D-CDE full volumes were obtained at color Doppler volume rates of 15, 20 and 27 volumes/s. Shunt flow derived from RT3-D-CDE was linearly correlated with pump-driven stroke volume (R = 0.982). RT3-D-CDE-derived shunt volumes from three color Doppler flow rate settings and two stroke rate acquisitions did not differ (p > 0.05). The use of RT3-D-CDE to determine shunt volume though VSDs is feasible. Different color volume rates/heart rates under clinically/physiologically relevant range have no effect on VSD 3-D shunt volume determination. PMID:26850842

  7. 3D full-waveform inversion of time-lapse horizontal borehole GPR data to map soil water content variability

    NASA Astrophysics Data System (ADS)

    Klotzsche, A.; Van Der Kruk, J.; Oberroehrmann, M.; Vanderborght, J.; Vereecken, H.

    2015-12-01

    Soil moisture is a key state variable that controls water and mass fluxes in soil-plant systems and is variable in space and time. Over the last year's, hydrogeophysical methods such as ground penetrating radar (GPR) have been used to determine electromagnetic properties as proxies for soil water content (SWC). Here, we combined zero-offset-profiles (ZOP) GPR measurements within multiple horizontal minirhizotubes at different depths to determine the spatial and temporal variability of SWC under a winter wheat stand at the Selhausen test site (Germany). We studied spatio-temporal variations of SWC under three different treatments: rainfed, irrigated and sheltered. We acquired 15 time-lapse ZOP GPR dataset during the growing season of the wheat in the rhizotron facility using horizontal boreholes with a separation of 0.75m and a length of 6m at six depths between 0.1-1.2m. The obtained radar velocities were converted to SWC using the 4-phase volumetric complex refractive index model. SWC values obtained using standard ray-based processing methods were not reliable close to the surface (0.1-0.2m depth) because of the inference of the critically refracted air wave and the direct wave through the subsurface. Therefore, we implemented a full-waveform inversion that uses accurate 3D forward modeling of GPRMax that incorporates the air and soil interactions. The shuffled complex evolution (SCE) method allowed us to retrieve quantitative medium properties that explained the measured data with a R² of at least 0.95, and improved SWC estimates at all depths. The final SWC distributions for wet and dry conditions showed that the vertical variability is significantly larger than the lateral variability caused by strong influence of precipitation and irrigation events.

  8. Miniature terahertz time-domain spectrometry

    NASA Astrophysics Data System (ADS)

    Schulkin, Brian

    This thesis focuses on the design, development and evaluation of novel concepts which enable the miniaturization of terahertz (THz) time-domain spectrometry. Portable THz spectrometry is applied to research and industrial domains for immediate, short and long term applications in nondestructive evaluation, homeland security, and biomedicine respectively. Due to the previous limitation of THz devices for public uses, in particular, the lack of access to a THz spectrometer, applications of THz science and technology have only recently expanded beyond the laboratory. There is an urgent need for compact, even handheld THz time-domain spectrometry (THz-TDS) platforms which can carry out proven-to-be-useful applications developed and tested in laboratory conditions. There are three major challenges restricting THz-TDS to laboratories. Atmospheric absorption severely limits the propagation distance of the THz beam and confines systems to low-moisture environments. The sample's surface roughness, grain size and geometry severely limit the bandwidth of the measurement. Physical size and weight of THz systems are generally limited by large laser sources and optomechanics. The sensitivity and selectivity of THz-TDS systems are the two most significant parameters used to describe the quality of the system. Sensitivity is directly related to the Signal-to-Noise Ratio (SNR) and dynamic range, which may be improved by either lowering the noise floor or increasing the THz signal. On the other hand, selectivity is far more complex as it is related to the sensitivity, sample preparation, baseline correction, and selection method. Sensitivity is gauged using industrial statistical methods, such as Gauge Repeatability and Reproducibility (GR&R), and can transform a not-so-useful SNR value to an extremely useful measure of the minimum detectable amount of a certain material. It is shown that the GR&R value is inversely proportional to the square root of the number of averaged waveforms

  9. Efficient 3-D frequency-domain mono-parameter full-waveform inversion of ocean-bottom cable data: application to Valhall in the visco-acoustic vertical transverse isotropic approximation

    NASA Astrophysics Data System (ADS)

    Operto, S.; Miniussi, A.; Brossier, R.; Combe, L.; Métivier, L.; Monteiller, V.; Ribodetti, A.; Virieux, J.

    2015-08-01

    Computationally efficient 3-D frequency-domain full waveform inversion (FWI) is applied to ocean-bottom cable data from the Valhall oil field in the visco-acoustic vertical transverse isotropic (VTI) approximation. Frequency-domain seismic modelling is performed with a parallel sparse direct solver on a limited number of computer nodes. A multiscale imaging is performed by successive inversions of single frequencies in the 3.5-10 Hz frequency band. The vertical wave speed is updated during FWI while density, quality factor QP and anisotropic Thomsen's parameters δ and ɛ are kept fixed to their initial values. The final FWI model shows the resolution improvement that was achieved compared to the initial model that was built by reflection traveltime tomography. This FWI model shows a glacial channel system at 175 m depth, the footprint of drifting icebergs on the palaeo-seafloor at 500 m depth, a detailed view of a gas cloud at 1 km depth and the base cretaceous reflector at 3.5 km depth. The relevance of the FWI model is assessed by frequency-domain and time-domain seismic modelling and source wavelet estimation. The agreement between the modelled and recorded data in the frequency domain is excellent up to 10 Hz although amplitudes of modelled wavefields propagating across the gas cloud are overestimated. This might highlight the footprint of attenuation, whose absorption effects are underestimated by the homogeneous background QP model (QP = 200). The match between recorded and modelled time-domain seismograms suggests that the inversion was not significantly hampered by cycle skipping. However, late arrivals in the synthetic seismograms, computed without attenuation and with a source wavelet estimated from short-offset early arrivals, arrive 40 ms earlier than the recorded seismograms. This might result from dispersion effects related to attenuation. The repeatability of the source wavelets inferred from data that are weighted by a linear gain with offset is

  10. Domain structure of black hole space-times

    SciTech Connect

    Harmark, Troels

    2009-07-15

    We introduce the domain structure for stationary black hole space-times. The domain structure lives on the submanifold of fixed points of the Killing vector fields. Depending on which Killing vector field has fixed points the submanifold is naturally divided into domains. The domain structure provides invariants of the space-time, both topological and continuous. It is defined for any space-time dimension and any number of Killing vector fields. We examine the domain structure for asymptotically flat space-times and find a canonical form for the metric of such space-times. The domain structure generalizes the rod structure introduced for space-times with D-2 commuting Killing vector fields. We analyze in detail the domain structure for Minkowski space, the Schwarzschild-Tangherlini black hole and the Myers-Perry black hole in six and seven dimensions. Finally, we consider the possible domain structures for asymptotically flat black holes in six and seven dimensio0008.

  11. Surgery for ruptured sinus of valsalva aneurysm into right ventricular outflow tract: role of intraoperative 2D and real time 3D transesophageal echocardiography.

    PubMed

    Gadhinglajkar, Shrinivas; Sreedhar, Rupa

    2010-08-01

    A major limitation of the 2D echocardiography during surgery for a complex cardiac lesion is its inability to provide an accurate spatial orientation of the structure. The real time 3D transesophageal echocardiography (RT-3D-TEE) technology available in Philips IE 33 ultrasound machine is relatively new to an operation suite. We evaluated its intraoperative utility in a patient, who was operated for repair of a ruptured sinus of Valsalva aneurysm (RSOVA) and closure of a supracristal ventricular septal defect. The VSD and RSOVA were visualized through different virtual windows in a more promising way on intraoperative RT-3D-TEE than on the 2D echocardiography. The acquired images could be virtually cropped and displayed in anatomical views to the operating surgeon for a clear orientation to the anatomy of the lesion. RT-3D-TEE is a potential intraoperative monitoring tool in surgeries for complex cardiac lesions. PMID:21050263

  12. Real-time 3D shape measurement with digital stripe projection by Texas Instruments Micro Mirror Devices DMD

    NASA Astrophysics Data System (ADS)

    Frankowski, Gottfried; Chen, Mai; Huth, Torsten

    2000-03-01

    The fast, contact-free and highly precise shape measurement of technical objects is of key importance in the scientific- technological area as well as the area of practical measurement technology. The application areas of contact- free surface measurement extend across widely different areas, e.g., the automation of production processes, the measurement and inspection of components in microsystem technology or the fast 3D in-vivo measurement of human skin surfaces in cosmetics and medical technology. This paper describes methodological and technological possibilities as well as measurement technology applications for fast optical 3D shape measurements using micromirror-based high-velocity stripe projection. Depending on the available projector and camera facilities, it will be possible to shoot and evaluate compete 3D surface profiles within only a few milliseconds.

  13. On the Analysis Methods for the Time Domain and Frequency Domain Response of a Buried Objects*

    NASA Astrophysics Data System (ADS)

    Poljak, Dragan; Šesnić, Silvestar; Cvetković, Mario

    2014-05-01

    There has been a continuous interest in the analysis of ground-penetrating radar systems and related applications in civil engineering [1]. Consequently, a deeper insight of scattering phenomena occurring in a lossy half-space, as well as the development of sophisticated numerical methods based on Finite Difference Time Domain (FDTD) method, Finite Element Method (FEM), Boundary Element Method (BEM), Method of Moments (MoM) and various hybrid methods, is required, e.g. [2], [3]. The present paper deals with certain techniques for time and frequency domain analysis, respectively, of buried conducting and dielectric objects. Time domain analysis is related to the assessment of a transient response of a horizontal straight thin wire buried in a lossy half-space using a rigorous antenna theory (AT) approach. The AT approach is based on the space-time integral equation of the Pocklington type (time domain electric field integral equation for thin wires). The influence of the earth-air interface is taken into account via the simplified reflection coefficient arising from the Modified Image Theory (MIT). The obtained results for the transient current induced along the electrode due to the transmitted plane wave excitation are compared to the numerical results calculated via an approximate transmission line (TL) approach and the AT approach based on the space-frequency variant of the Pocklington integro-differential approach, respectively. It is worth noting that the space-frequency Pocklington equation is numerically solved via the Galerkin-Bubnov variant of the Indirect Boundary Element Method (GB-IBEM) and the corresponding transient response is obtained by the aid of inverse fast Fourier transform (IFFT). The results calculated by means of different approaches agree satisfactorily. Frequency domain analysis is related to the assessment of frequency domain response of dielectric sphere using the full wave model based on the set of coupled electric field integral

  14. Three-dimensional finite difference time domain modeling of the Earth-ionosphere cavity resonances

    NASA Astrophysics Data System (ADS)

    Yang, Heng; Pasko, Victor P.

    2005-02-01

    Comparison of results from a three-dimensional (3-D) finite difference time domain (FDTD) model of Schumann resonances (SR) with a set of classical eigenfrequency and quality factor solutions for laterally uniform spherically symmetric Earth-ionosphere cavity and recent SR observations during solar proton events (SPEs) and X-ray bursts demonstrate the potential and applicability of the FDTD technique for studies of realistic SR problems.

  15. Casimir forces in the time domain: Applications

    SciTech Connect

    McCauley, Alexander P.; Rodriguez, Alejandro W.; Joannopoulos, John D.; Johnson, Steven G.

    2010-01-15

    Our previous article [Phys. Rev. A 80, 012115 (2009)] introduced a method to compute Casimir forces in arbitrary geometries and for arbitrary materials that was based on a finite-difference time-domain (FDTD) scheme. In this article, we focus on the efficient implementation of our method for geometries of practical interest and extend our previous proof-of-concept algorithm in one dimension to problems in two and three dimensions, introducing a number of new optimizations. We consider Casimir pistonlike problems with nonmonotonic and monotonic force dependence on sidewall separation, both for previously solved geometries to validate our method and also for new geometries involving magnetic sidewalls and/or cylindrical pistons. We include realistic dielectric materials to calculate the force between suspended silicon waveguides or on a suspended membrane with periodic grooves, also demonstrating the application of perfectly matched layer (PML) absorbing boundaries and/or periodic boundaries. In addition, we apply this method to a realizable three-dimensional system in which a silica sphere is stably suspended in a fluid above an indented metallic substrate. More generally, the method allows off-the-shelf FDTD software, already supporting a wide variety of materials (including dielectric, magnetic, and even anisotropic materials) and boundary conditions, to be exploited for the Casimir problem.

  16. How Swift is redefining time domain astronomy

    NASA Astrophysics Data System (ADS)

    Gehrels, N.; Cannizzo, J. K.

    2015-09-01

    NASA's Swift satellite has completed ten years of amazing discoveries in time domain astronomy. Its primary mission is to chase gamma-ray bursts (GRBs), but due to its scheduling flexibility it has subsequently become a prime discovery machine for new types of behavior. The list of major discoveries in GRBs and other transients includes the long-lived X-ray afterglows and flares from GRBs, the first accurate localization of short GRBs, the discovery of GRBs at high redshift (z > 8), supernova shock break-out from SN Ib, a jetted tidal disruption event, an ultra-long class of GRBs, high energy emission from flare stars, novae and supernovae with unusual characteristics, magnetars with glitches in their spin periods, and a short GRB with evidence of an accompanying kilonova. Swift has developed a dynamic synergism with ground based observatories. In a few years gravitational wave observatories will come on-line and provide exciting new transient sources for Swift to study.

  17. Reengineering observatory operations for the time domain

    NASA Astrophysics Data System (ADS)

    Seaman, Robert L.; Vestrand, W. T.; Hessman, Frederic V.

    2014-07-01

    Observatories are complex scientific and technical institutions serving diverse users and purposes. Their telescopes, instruments, software, and human resources engage in interwoven workflows over a broad range of timescales. These workflows have been tuned to be responsive to concepts of observatory operations that were applicable when various assets were commissioned, years or decades in the past. The astronomical community is entering an era of rapid change increasingly characterized by large time domain surveys, robotic telescopes and automated infrastructures, and - most significantly - of operating modes and scientific consortia that span our individual facilities, joining them into complex network entities. Observatories must adapt and numerous initiatives are in progress that focus on redesigning individual components out of the astronomical toolkit. New instrumentation is both more capable and more complex than ever, and even simple instruments may have powerful observation scripting capabilities. Remote and queue observing modes are now widespread. Data archives are becoming ubiquitous. Virtual observatory standards and protocols and astroinformatics data-mining techniques layered on these are areas of active development. Indeed, new large-aperture ground-based telescopes may be as expensive as space missions and have similarly formal project management processes and large data management requirements. This piecewise approach is not enough. Whatever challenges of funding or politics facing the national and international astronomical communities it will be more efficient - scientifically as well as in the usual figures of merit of cost, schedule, performance, and risks - to explicitly address the systems engineering of the astronomical community as a whole.

  18. Two-dimensional and 3-D images of thick tissue using time-constrained times-of-flight and absorbance spectrophotometry

    NASA Astrophysics Data System (ADS)

    Benaron, David A.; Lennox, M.; Stevenson, David K.

    1992-05-01

    Reconstructing deep-tissue images in real time using spectrophotometric data from optically diffusing thick tissues has been problematic. Continuous wave applications (e.g., pulse oximetry, regional cerebral saturation) ignore both the multiple paths traveled by the photons through the tissue and the effects of scattering, allowing scalar measurements but only under limited conditions; interferometry works poorly in thick, highly-scattering media; frequency- modulated approaches may not allow full deconvolution of scattering and absorbance; and pulsed-light techniques allow for preservation of information regarding the multiple paths taken by light through the tissue, but reconstruction is both computation intensive and limited by the relative surface area available for detection of photons. We have developed a picosecond times-of-flight and absorbance (TOFA) optical system, time-constrained to measure only photons with a narrow range of path lengths and arriving within a narrow angel of the emitter-detector axis. The delay until arrival of the earliest arriving photons is a function of both the scattering and absorbance of the tissues in a direct line between the emitter and detector, reducing the influence of surrounding tissues. Measurement using a variety of emitter and detector locations produces spatial information which can be analyzed in a standard 2-D grid, or subject to computer reconstruction to produce tomographic images representing 3-D structure. Using such a technique, we have been able to demonstrate the principles of tc-TOFA, detect and localize diffusive and/or absorptive objects suspended in highly scattering media (such as blood admixed with yeast), and perform simple 3-D reconstructions using phantom objects. We are now attempting to obtain images in vivo. Potential future applications include use as a research tool, and as a continuous, noninvasive, nondestructive monitor in diagnostic imaging, fetal monitoring, neurologic and cardiac

  19. Flying triangulation - A motion-robust optical 3D sensor for the real-time shape acquisition of complex objects

    NASA Astrophysics Data System (ADS)

    Willomitzer, Florian; Ettl, Svenja; Arold, Oliver; Häusler, Gerd

    2013-05-01

    The three-dimensional shape acquisition of objects has become more and more important in the last years. Up to now, there are several well-established methods which already yield impressive results. However, even under quite common conditions like object movement or a complex shaping, most methods become unsatisfying. Thus, the 3D shape acquisition is still a difficult and non-trivial task. We present our measurement principle "Flying Triangulation" which enables a motion-robust 3D acquisition of complex-shaped object surfaces by a freely movable handheld sensor. Since "Flying Triangulation" is scalable, a whole sensor-zoo for different object sizes is presented. Concluding, an overview of current and future fields of investigation is given.

  20. Four-directional stereo-microscopy for 3D particle tracking with real-time error evaluation.

    PubMed

    Hay, R F; Gibson, G M; Lee, M P; Padgett, M J; Phillips, D B

    2014-07-28

    High-speed video stereo-microscopy relies on illumination from two distinct angles to create two views of a sample from different directions. The 3D trajectory of a microscopic object can then be reconstructed using parallax to combine 2D measurements of its position in each image. In this work, we evaluate the accuracy of 3D particle tracking using this technique, by extending the number of views from two to four directions. This allows us to record two independent sets of measurements of the 3D coordinates of tracked objects, and comparison of these enables measurement and minimisation of the tracking error in all dimensions. We demonstrate the method by tracking the motion of an optically trapped microsphere of 5 μm in diameter, and find an accuracy of 2-5 nm laterally, and 5-10 nm axially, representing a relative error of less than 2.5% of its range of motion in each dimension. PMID:25089484

  1. Real-time 3D image reconstruction of a 24×24 row-column addressing array: from raw data to image

    NASA Astrophysics Data System (ADS)

    Li, Chunyu; Yang, Jiali; Li, Xu; Zhong, Xiaoli; Song, Junjie; Ding, Mingyue; Yuchi, Ming

    2016-04-01

    This paper presents a work of real-time 3-D image reconstruction for a 7.5-MHz, 24×24 row-column addressing array transducer. The transducer works with a predesigned transmit/receive module. After the raw data are captured by the NI PXIe data acquisition (DAQ) module, the following processing procedures are performed: delay and sum (DAS), base-line calibration, envelope detection, logarithm compression, down-sampling, gray scale mapping and 3-D display. These procedures are optimized for obtaining real-time 3-D images. Fixed-point focusing scheme is applied in delay and sum (DAS) to obtain line data from channel data. Zero-phase high-pass filter is used to calibrate the base-line shift of echo. The classical Hilbert transformation is adopted to detect the envelopes of echo. Logarithm compression is implemented to enlarge the weak signals and narrow the gap from the strong ones. Down-sampling reduces the amount of data to improve the processing speed. Linear gray scale mapping is introduced that the weakest signal is mapped to 0 and the strongest signal 255. The real-time 3-D images are displayed with multi-planar mode, which shows three orthogonal sections (vertical section, coronal section, transverse section). A trigger signal is sent from the transmit/receive module to the DAQ module at the start of each volume data generation to ensure synchronization between these two modules. All procedures, include data acquisition (DAQ), signal processing and image display, are programmed on the platform of LabVIEW. 675MB raw echo data are acquired in one minute to generate 24×24×48, 27fps 3-D images. The experiment on the strong reflection object (aluminum slice) shows the feasibility of the whole process from raw data to real-time 3-D images.

  2. Joint inversion of seismic travel times and gravity data on 3D unstructured grids with application to mineral exploration

    NASA Astrophysics Data System (ADS)

    Lelievre, Peter; Farquharson, Colin; Hurich, Charles

    2010-05-01

    methods for use when such a relationship is not available or can not be prescribed. In our joint inversion approach, we discretise the subsurface on an unstructured tetrahedral 3D grid, which, compared to rectilinear discretisation, allows 1) efficient generation of complicated subsurface geometries when such information is known a priori, and 2) can significantly reduce the problem size. The Fast Marching Method is used for the first arrival travel time forward solution and the gravity solution can be calculated using an analytic response for tetrahedra or via a finite element solution to Poisson's equation. When an empirical relationship between physical properties can be developed, our inversion approach can enforce that relationship to some degree commensurate with our confidence in the relationship. In the absence of an empirical relationship, we employ a correlation measure to encourage the properties to maintain a general linear or log-linear relationship. Again, the strength of this correlation constraint can be adjusted based on our confidence in the underlying assumption. In a further extension, we apply an additional fuzzy c-mean measure to encourage the recovered physical property distributions to cluster following the characteristics of the joint physical property distributions determined a priori. If such a priori information is not available, suitable cluster locations can be estimated through an iterative strategy. Rather than moving to a computationally intensive statistical sampling methodology, we work in a deterministic framework, where well-behaved functions are minimized via a descent search. After some instructional mathematical preliminaries, we present our methods on synthetic and real data scenarios from the Voisey's Bay massive sulphide deposit in Labrador, Canada.

  3. An efficient method of 3-D elastic full waveform inversion using a finite-difference injection method for time-lapse imaging

    NASA Astrophysics Data System (ADS)

    Borisov, Dmitry; Singh, Satish C.; Fuji, Nobuaki

    2015-09-01

    Seismic full waveform inversion is an objective method to estimate elastic properties of the subsurface and is an important area of research, particularly in seismic exploration community. It is a data-fitting approach, where the difference between observed and synthetic data is minimized iteratively. Due to a very high computational cost, the practical implementation of waveform inversion has so far been restricted to a 2-D geometry with different levels of physics incorporated in it (e.g. elasticity/viscoelasticity) or to a 3-D geometry but using an acoustic approximation. However, the earth is three-dimensional, elastic and heterogeneous and therefore a full 3-D elastic inversion is required in order to obtain more accurate and valuable models of the subsurface. Despite the recent increase in computing power, the application of 3-D elastic full waveform inversion to real-scale problems remains quite challenging on the current computer architecture. Here, we present an efficient method to perform 3-D elastic full waveform inversion for time-lapse seismic data using a finite-difference injection method. In this method, the wavefield is computed in the whole model and is stored on a surface above a finite volume where the model is perturbed and localized inversion is performed. Comparison of the final results using the 3-D finite-difference injection method and conventional 3-D inversion performed within the whole volume shows that our new method provides significant reductions in computational time and memory requirements without any notable loss in accuracy. Our approach shows a big potential for efficient reservoir monitoring in real time-lapse experiments.

  4. 3D microscope

    NASA Astrophysics Data System (ADS)

    Iizuka, Keigo

    2008-02-01

    In order to circumvent the fact that only one observer can view the image from a stereoscopic microscope, an attachment was devised for displaying the 3D microscopic image on a large LCD monitor for viewing by multiple observers in real time. The principle of operation, design, fabrication, and performance are presented, along with tolerance measurements relating to the properties of the cellophane half-wave plate used in the design.

  5. Improving Three-Dimensional (3D) Range Gated Reconstruction Through Time-of-Flight (TOF) Imaging Analysis

    NASA Astrophysics Data System (ADS)

    Chua, S. Y.; Wang, X.; Guo, N.; Tan, C. S.; Chai, T. Y.; Seet, G. L.

    2016-04-01

    This paper performs an experimental investigation on the TOF imaging profile which strongly influences the quality of reconstruction to accomplish accurate range sensing. From our analysis, the reflected intensity profile recorded appears to deviate from Gaussian model which is commonly assumed and can be perceived as a mixture of noises and actual reflected signal. Noise-weighted Average range calculation is therefore proposed to alleviate noise influence based on the signal detection threshold and system noises. From our experimental result, this alternative range solution demonstrates better accuracy as compared to the conventional weighted average method and proven as a para-axial correction to improve range reconstruction in 3D gated imaging system.

  6. Real-time motion- and B0-correction for LASER-localized spiral-accelerated 3D-MRSI of the brain at 3T

    PubMed Central

    Bogner, Wolfgang; Hess, Aaron T; Gagoski, Borjan; Tisdall, M. Dylan; van der Kouwe, Andre J.W.; Trattnig, Siegfried; Rosen, Bruce; Andronesi, Ovidiu C

    2013-01-01

    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. PMID:24201013

  7. A parallel domain decomposition-based implicit method for the Cahn-Hilliard-Cook phase-field equation in 3D

    NASA Astrophysics Data System (ADS)

    Zheng, Xiang; Yang, Chao; Cai, Xiao-Chuan; Keyes, David

    2015-03-01

    We present a numerical algorithm for simulating the spinodal decomposition described by the three dimensional Cahn-Hilliard-Cook (CHC) equation, which is a fourth-order stochastic partial differential equation with a noise term. The equation is discretized in space and time based on a fully implicit, cell-centered finite difference scheme, with an adaptive time-stepping strategy designed to accelerate the progress to equilibrium. At each time step, a parallel Newton-Krylov-Schwarz algorithm is used to solve the nonlinear system. We discuss various numerical and computational challenges associated with the method. The numerical scheme is validated by a comparison with an explicit scheme of high accuracy (and unreasonably high cost). We present steady state solutions of the CHC equation in two and three dimensions. The effect of the thermal fluctuation on the spinodal decomposition process is studied. We show that the existence of the thermal fluctuation accelerates the spinodal decomposition process and that the final steady morphology is sensitive to the stochastic noise. We also show the evolution of the energies and statistical moments. In terms of the parallel performance, it is found that the implicit domain decomposition approach scales well on supercomputers with a large number of processors.

  8. A parallel domain decomposition-based implicit method for the Cahn–Hilliard–Cook phase-field equation in 3D

    SciTech Connect

    Zheng, Xiang; Yang, Chao; Cai, Xiao-Chuan; Keyes, David

    2015-03-15

    We present a numerical algorithm for simulating the spinodal decomposition described by the three dimensional Cahn–Hilliard–Cook (CHC) equation, which is a fourth-order stochastic partial differential equation with a noise term. The equation is discretized in space and time based on a fully implicit, cell-centered finite difference scheme, with an adaptive time-stepping strategy designed to accelerate the progress to equilibrium. At each time step, a parallel Newton–Krylov–Schwarz algorithm is used to solve the nonlinear system. We discuss various numerical and computational challenges associated with the method. The numerical scheme is validated by a comparison with an explicit scheme of high accuracy (and unreasonably high cost). We present steady state solutions of the CHC equation in two and three dimensions. The effect of the thermal fluctuation on the spinodal decomposition process is studied. We show that the existence of the thermal fluctuation accelerates the spinodal decomposition process and that the final steady morphology is sensitive to the stochastic noise. We also show the evolution of the energies and statistical moments. In terms of the parallel performance, it is found that the implicit domain decomposition approach scales well on supercomputers with a large number of processors.

  9. 3D Elastic Wavefield Tomography

    NASA Astrophysics Data System (ADS)

    Guasch, L.; Warner, M.; Stekl, I.; Umpleby, A.; Shah, N.

    2010-12-01

    Wavefield tomography, or waveform inversion, aims to extract the maximum information from seismic data by matching trace by trace the response of the solid earth to seismic waves using numerical modelling tools. Its first formulation dates from the early 80's, when Albert Tarantola developed a solid theoretical basis that is still used today with little change. Due to computational limitations, the application of the method to 3D problems has been unaffordable until a few years ago, and then only under the acoustic approximation. Although acoustic wavefield tomography is widely used, a complete solution of the seismic inversion problem requires that we account properly for the physics of wave propagation, and so must include elastic effects. We have developed a 3D tomographic wavefield inversion code that incorporates the full elastic wave equation. The bottle neck of the different implementations is the forward modelling algorithm that generates the synthetic data to be compared with the field seismograms as well as the backpropagation of the residuals needed to form the direction update of the model parameters. Furthermore, one or two extra modelling runs are needed in order to calculate the step-length. Our approach uses a FD scheme explicit time-stepping by finite differences that are 4th order in space and 2nd order in time, which is a 3D version of the one developed by Jean Virieux in 1986. We chose the time domain because an explicit time scheme is much less demanding in terms of memory than its frequency domain analogue, although the discussion of wich domain is more efficient still remains open. We calculate the parameter gradients for Vp and Vs by correlating the normal and shear stress wavefields respectively. A straightforward application would lead to the storage of the wavefield at all grid points at each time-step. We tackled this problem using two different approaches. The first one makes better use of resources for small models of dimension equal

  10. Real-time 3D millimeter wave imaging based FMCW using GGD focal plane array as detectors

    NASA Astrophysics Data System (ADS)

    Levanon, Assaf; Rozban, Daniel; Kopeika, Natan S.; Yitzhaky, Yitzhak; Abramovich, Amir

    2014-03-01

    Millimeter wave (MMW) imaging systems are required for applications in medicine, communications, homeland security, and space technology. This is because there is no known ionization hazard for biological tissue, and atmospheric attenuation in this range of the spectrum is relatively low. The lack of inexpensive room temperature imaging systems makes it difficult to give a suitable MMW system for many of the above applications. 3D MMW imaging system based on chirp radar was studied previously using a scanning imaging system of a single detector. The system presented here proposes to employ a chirp radar method with a Glow Discharge Detector (GDD) Focal Plane Array (FPA) of plasma based detectors. Each point on the object corresponds to a point in the image and includes the distance information. This will enable 3D MMW imaging. The radar system requires that the millimeter wave detector (GDD) will be able to operate as a heterodyne detector. Since the source of radiation is a frequency modulated continuous wave (FMCW), the detected signal as a result of heterodyne detection gives the object's depth information according to value of difference frequency, in addition to the reflectance of the image. In this work we experimentally demonstrate the feasibility of implementing an imaging system based on radar principles and FPA of GDD devices. This imaging system is shown to be capable of imaging objects from distances of at least 10 meters.

  11. Real-Time 3D Fluoroscopy-Guided Large Core Needle Biopsy of Renal Masses: A Critical Early Evaluation According to the IDEAL Recommendations

    SciTech Connect

    Kroeze, Stephanie G. C.; Huisman, Merel; Verkooijen, Helena M.; Diest, Paul J. van; Ruud Bosch, J. L. H.; Bosch, Maurice A. A. J. van den

    2012-06-15

    Introduction: Three-dimensional (3D) real-time fluoroscopy cone beam CT is a promising new technique for image-guided biopsy of solid tumors. We evaluated the technical feasibility, diagnostic accuracy, and complications of this technique for guidance of large-core needle biopsy in patients with suspicious renal masses. Methods: Thirteen patients with 13 suspicious renal masses underwent large-core needle biopsy under 3D real-time fluoroscopy cone beam CT guidance. Imaging acquisition and subsequent 3D reconstruction was done by a mobile flat-panel detector (FD) C-arm system to plan the needle path. Large-core needle biopsies were taken by the interventional radiologist. Technical success, accuracy, and safety were evaluated according to the Innovation, Development, Exploration, Assessment, Long-term study (IDEAL) recommendations. Results: Median tumor size was 2.6 (range, 1.0-14.0) cm. In ten (77%) patients, the histological diagnosis corresponded to the imaging findings: five were malignancies, five benign lesions. Technical feasibility was 77% (10/13); in three patients biopsy results were inconclusive. The lesion size of these three patients was <2.5 cm. One patient developed a minor complication. Median follow-up was 16.0 (range, 6.4-19.8) months. Conclusions: 3D real-time fluoroscopy cone beam CT-guided biopsy of renal masses is feasible and safe. However, these first results suggest that diagnostic accuracy may be limited in patients with renal masses <2.5 cm.

  12. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-01-01

    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.  

  13. Estimating the Temporal Domain when the Discount of the Net Evaporation Term Affects the Resulting Net Precipitation Pattern in the Moisture Budget Using a 3-D Lagrangian Approach

    PubMed Central

    Castillo, Rodrigo; Nieto, Raquel; Drumond, Anita; Gimeno, Luis

    2014-01-01

    The Lagrangian FLEXPART model has been used during the last decade to detect moisture sources that affect the climate in different regions of the world. While most of these studies provided a climatological perspective on the atmospheric branch of the hydrological cycle in terms of precipitation, none assessed the minimum temporal domain for which the climatological approach is valid. The methodology identifies the contribution of humidity to the moisture budget in a region by computing the changes in specific humidity along backward (or forward) trajectories of air masses over a period of ten days beforehand (afterwards), thereby allowing the calculation of monthly, seasonal and annual averages. The current study calculates as an example the climatological seasonal mean and variance of the net precipitation for regions in which precipitation exceeds evaporation (E-P<0) for the North Atlantic moisture source region using different time periods, for winter and summer from 1980 to 2000. The results show that net evaporation (E-P>0) can be discounted after when the integration of E-P is done without affecting the general net precipitation patterns when it is discounted in a monthly or longer time scale. PMID:24893002

  14. Time-Domain Impedance Boundary Conditions for Computational Aeroacoustics

    NASA Technical Reports Server (NTRS)

    Tam, Christopher K. W.; Auriault, Laurent

    1996-01-01

    It is an accepted practice in aeroacoustics to characterize the properties of an acoustically treated surface by a quantity known as impedance. Impedance is a complex quantity. As such, it is designed primarily for frequency-domain analysis. Time-domain boundary conditions that are the equivalent of the frequency-domain impedance boundary condition are proposed. Both single frequency and model broadband time-domain impedance boundary conditions are provided. It is shown that the proposed boundary conditions, together with the linearized Euler equations, form well-posed initial boundary value problems. Unlike ill-posed problems, they are free from spurious instabilities that would render time-marching computational solutions impossible.

  15. Frequency and time domain modeling of high speed amplifier

    NASA Astrophysics Data System (ADS)

    Opalska, Katarzyna

    2015-09-01

    The paper presents the lumped model of high speed amplifier useful for frequency and time domain (also large signal) simulation. Model is constructed on the basis of two-domain device measurements, namely small signal frequency parameters and time response to the input step of varying amplitude. Rational approximation of frequency domain data leads to small signal model composed of RLC subcircuits and controlled sources. Next, the model is complimented with the nonlinearities identified from time-domain measurements, including those taken for large input signals. Final amplifier model implemented in SPICE simulator is shown to correctly render the behavior of the device over the wide variety of operating conditions.

  16. A statistical package for computing time and frequency domain analysis

    NASA Technical Reports Server (NTRS)

    Brownlow, J.

    1978-01-01

    The spectrum analysis (SPA) program is a general purpose digital computer program designed to aid in data analysis. The program does time and frequency domain statistical analyses as well as some preanalysis data preparation. The capabilities of the SPA program include linear trend removal and/or digital filtering of data, plotting and/or listing of both filtered and unfiltered data, time domain statistical characterization of data, and frequency domain statistical characterization of data.

  17. Monitoring time course of human whole blood coagulation using a microfluidic dielectric sensor with a 3D capacitive structure.

    PubMed

    Maji, Debnath; Suster, Michael A; Stavrou, Evi; Gurkan, Umut A; Mohseni, Pedram

    2015-08-01

    This paper reports on the design, fabrication, and testing of a microfluidic sensor for dielectric spectroscopy (DS) of human whole blood during coagulation. The sensor employs a three-dimensional (3D), parallel-plate, capacitive sensing structure with a floating electrode integrated into a microfluidic channel. Using an impedance analyzer and after a 5-point calibration, the sensor is shown to measure the real part of complex relative dielectric permittivity of human whole blood in a frequency range of 10kHz to 100MHz. The temporal variation of dielectric permittivity at 1MHz for human whole blood from three different healthy donors shows a peak in permittivity at ~ 4 to 5 minutes, which also corresponds to the onset of CaCl2-initiated coagulation of the blood sample verified visually. PMID:26737635

  18. Bedside assistance in freehand ultrasonic diagnosis by real-time visual feedback of 3D scatter diagram of pulsatile tissue-motion

    NASA Astrophysics Data System (ADS)

    Fukuzawa, M.; Kawata, K.; Nakamori, N.; Kitsunezuka, Y.

    2011-03-01

    By real-time visual feedback of 3D scatter diagram of pulsatile tissue-motion, freehand ultrasonic diagnosis of neonatal ischemic diseases has been assisted at the bedside. The 2D ultrasonic movie was taken with a conventional ultrasonic apparatus (ATL HDI5000) and ultrasonic probes of 5-7 MHz with the compact tilt-sensor to measure the probe orientation. The real-time 3D visualization was realized by developing an extended version of the PC-based visualization system. The software was originally developed on the DirectX platform and optimized with the streaming SIMD extensions. The 3D scatter diagram of the latest pulsatile tissues has been continuously generated and visualized as projection image with the ultrasonic movie in the current section more than 15 fps. It revealed the 3D structure of pulsatile tissues such as middle and posterior cerebral arteries, Willis ring and cerebellar arteries, in which pediatricians have great interests in the blood flow because asphyxiated and/or low-birth-weight neonates have a high risk of ischemic diseases such as hypoxic-ischemic encephalopathy and periventricular leukomalacia. Since the pulsatile tissue-motion is due to local blood flow, it can be concluded that the system developed in this work is very useful to assist freehand ultrasonic diagnosis of ischemic diseases in the neonatal cranium.

  19. Three-dimensional time and Fourier domain endoscopic OCT using 2-axis scanning MEMS mirror

    NASA Astrophysics Data System (ADS)

    Jung, Woonggyu; McCormick, Daniel T.; Ahn, Yeh-Chan; Zhang, Jun; Tien, Norman C.; Chen, Zhongping

    2006-02-01

    We present a three-dimensional (3-D) endoscopic optical coherence tomography (OCT) system based on a dual axis microelectromechanical system (MEMS) mirror. The diameter of MEMS mirror was 1.2 mm and both axes were capable of scanning up to 20° (optical) at greater than 1 kHz with excellent linearity. The MEMS mirror was packaged in a machined acrylic endoscopic housing which provided mechanical protection and electrical interconnects as well as optical alignment of the MEMS device to a focusing GRIN lens. The endoscopic MEMS probe was integrated and tested with both a fiber-based time domain (TD) OCT system and Fourier domain (FD) OCT system. Combining the 2-axis lateral scanning of the MEMS device with an axial scan allowed 3-D volume images to be obtained at a rate of 3 frames/s for the TD system and 7 frames/s for the FD system. In the initial investigations, in vivo 3-D OCT images of a human finger as well as images of animal tissue such as healthy rabbit trachea, normal and cancerous regions of hamster cheek pouch tissue were obtained. These images allowed real-time diagnosis of diseased tissue and also clearly delineated important features and tissue structures.

  20. LLNL-Earth3D

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  1. Insights and questions raised from a multi-tracer plot-scale sprinkler experiment with time-lapse 3D GPR in a structured forested soil.

    NASA Astrophysics Data System (ADS)

    Jackisch, Conrad; Sprenger, Matthias; Allroggen, Niklas; van Schaik, Loes; Weiler, Markus; Zehe, Erwin

    2014-05-01

    Stable isotopes appear as ideal tracer commonly applied in preferential flow analyses. At the same time, central assumptions about signature mixing and propagation are founded on effective parameters merging advective and diffusive flow domains. However, in structured soils conditions are often far from well-mixed and some established assumptions may need to be reconsidered. We conducted a multi-tracer sprinkler experiment at a forested hillslope in the Attert Basin in Luxembourg with prevailing geogenic and biogenic preferential flow structures. At plot scale of 1x1 m2 we sprinkled two plots with 50 mm and one plot with 30 mm Brilliant Blue and Bromide enriched water for 1 hour. The experiments were accompanied by a high resolution 3D time-lapse GPR (Ground-Penetrating Radar) survey scanning 3x3 m2 before, directly after sprinkling and before excavation one day after sprinkling. Soil moisture was monitored with a TDR tube probe. Soil profiles were excavated and recorded for dye flow paths and for one medium resolution Bromide profile. In addition one core for pore water stable isotope analysis was taken before the sprinkling as reference and at each plot after sprinkling. We present the results with focus on the found evidence of preferential flow and the signals of the different tracers - especially the stable isotopes. While all other methods clearly show that only minor proportions of the soil took part in the infiltration process and that the sprinkler water has largely advectively propagated to the saprolite layer at about 80-100 cm depth, the stable isotopes signals from the cores indicate more intense interaction between the soil matrix and macropores, especially in the top 50 cm. This leads to the q