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Sample records for 3d cartesian tracking

  1. The 3D Euler solutions using automated Cartesian grid generation

    NASA Technical Reports Server (NTRS)

    Melton, John E.; Enomoto, Francis Y.; Berger, Marsha J.

    1993-01-01

    Viewgraphs on 3-dimensional Euler solutions using automated Cartesian grid generation are presented. Topics covered include: computational fluid dynamics (CFD) and the design cycle; Cartesian grid strategy; structured body fit; grid generation; prolate spheroid; and ONERA M6 wing.

  2. Shared Memory Parallelism for 3D Cartesian Discrete Ordinates Solver

    NASA Astrophysics Data System (ADS)

    Moustafa, Salli; Dutka-Malen, Ivan; Plagne, Laurent; Ponçot, Angélique; Ramet, Pierre

    2014-06-01

    This paper describes the design and the performance of DOMINO, a 3D Cartesian SN solver that implements two nested levels of parallelism (multicore+SIMD) on shared memory computation nodes. DOMINO is written in C++, a multi-paradigm programming language that enables the use of powerful and generic parallel programming tools such as Intel TBB and Eigen. These two libraries allow us to combine multi-thread parallelism with vector operations in an efficient and yet portable way. As a result, DOMINO can exploit the full power of modern multi-core processors and is able to tackle very large simulations, that usually require large HPC clusters, using a single computing node. For example, DOMINO solves a 3D full core PWR eigenvalue problem involving 26 energy groups, 288 angular directions (S16), 46 × 106 spatial cells and 1 × 1012 DoFs within 11 hours on a single 32-core SMP node. This represents a sustained performance of 235 GFlops and 40:74% of the SMP node peak performance for the DOMINO sweep implementation. The very high Flops/Watt ratio of DOMINO makes it a very interesting building block for a future many-nodes nuclear simulation tool.

  3. Development and Applications of 3D Cartesian CFD Technology

    NASA Technical Reports Server (NTRS)

    Melton, John E.; Berger, Marsha J.; VanDalsem, William (Technical Monitor)

    1994-01-01

    The urgent need for dramatic reductions in aircraft design cycle time is focusing scrutiny upon all aspects of computational fluid dynamics (CFD). These reductions will most likely come not from increased reliance upon user-interactive (and therefore time-expensive) methods, but instead from methods that can be fully automated and incorporated into 'black box' solutions. In comparison with tetrahedral methods, three-dimensional Cartesian grid approaches are in relative infancy, but initial experiences with automated Cartesian techniques are quite promising. Our research is targeted at furthering the development of Cartesian methods so that they can become key elements of a completely automatic grid generation/flow solution procedure applicable to the Euler analysis of complex aircraft geometries.

  4. Development and application of a 3D Cartesian grid Euler method

    NASA Technical Reports Server (NTRS)

    Melton, John E.; Aftosmis, Michael J.; Berger, Marsha J.; Wong, Michael D.

    1995-01-01

    This report describes recent progress in the development and application of 3D Cartesian grid generation and Euler flow solution techniques. Improvements to flow field grid generation algorithms, geometry representations, and geometry refinement criteria are presented, including details of a procedure for correctly identifying and resolving extremely thin surface features. An initial implementation of automatic flow field refinement is also presented. Results for several 3D multi-component configurations are provided and discussed.

  5. DOMINO: A fast 3D cartesian discrete ordinates solver for reference PWR simulations and SPN validation

    SciTech Connect

    Courau, T.; Moustafa, S.; Plagne, L.; Poncot, A.

    2013-07-01

    As part of its activity, EDF R and D is developing a new nuclear core simulation code named COCAGNE. This code relies on DIABOLO, a Simplified PN (SPN) method to compute the neutron flux inside the core for eigenvalue calculations. In order to assess the accuracy of SPN calculations, we have developed DOMINO, a new 3D Cartesian SN solver. The parallel implementation of DOMINO is very efficient and allows to complete an eigenvalue calculation involving around 300 x 10{sup 9} degrees of freedom within a few hours on a single shared-memory supercomputing node. This computation corresponds to a 26-group S{sub 8} 3D PWR core model used to assess the SPN accuracy. At the pin level, the maximal error for the SP{sub 5} DIABOLO fission production rate is lower than 0.2% compared to the S{sub 8} DOMINO reference for this 3D PWR core model. (authors)

  6. 3D camera tracking from disparity images

    NASA Astrophysics Data System (ADS)

    Kim, Kiyoung; Woo, Woontack

    2005-07-01

    In this paper, we propose a robust camera tracking method that uses disparity images computed from known parameters of 3D camera and multiple epipolar constraints. We assume that baselines between lenses in 3D camera and intrinsic parameters are known. The proposed method reduces camera motion uncertainty encountered during camera tracking. Specifically, we first obtain corresponding feature points between initial lenses using normalized correlation method. In conjunction with matching features, we get disparity images. When the camera moves, the corresponding feature points, obtained from each lens of 3D camera, are robustly tracked via Kanade-Lukas-Tomasi (KLT) tracking algorithm. Secondly, relative pose parameters of each lens are calculated via Essential matrices. Essential matrices are computed from Fundamental matrix calculated using normalized 8-point algorithm with RANSAC scheme. Then, we determine scale factor of translation matrix by d-motion. This is required because the camera motion obtained from Essential matrix is up to scale. Finally, we optimize camera motion using multiple epipolar constraints between lenses and d-motion constraints computed from disparity images. The proposed method can be widely adopted in Augmented Reality (AR) applications, 3D reconstruction using 3D camera, and fine surveillance systems which not only need depth information, but also camera motion parameters in real-time.

  7. A hybrid Cartesian/immersed boundary method for simulating flows with 3D, geometrically complex, moving bodies

    NASA Astrophysics Data System (ADS)

    Gilmanov, Anvar; Sotiropoulos, Fotis

    2005-08-01

    A numerical method is developed for solving the 3D, unsteady, incompressible Navier-Stokes equations in Cartesian domains containing immersed boundaries of arbitrary geometrical complexity moving with prescribed kinematics. The governing equations are discretized on a hybrid staggered/non-staggered grid layout using second-order accurate finite-difference formulas. The discrete equations are integrated in time via a second-order accurate dual-time-stepping, artificial compressibility iteration scheme. Unstructured, triangular meshes are employed to discretize complex immersed boundaries. The nodes of the surface mesh constitute a set of Lagrangian control points used to track the motion of the flexible body. At every instant in time, the influence of the body on the flow is accounted for by applying boundary conditions at Cartesian grid nodes located in the exterior but in the immediate vicinity of the body by reconstructing the solution along the local normal to the body surface. Grid convergence tests are carried out for the flow induced by an oscillating sphere in a cubic cavity, which show that the method is second-order accurate. The method is validated by applying it to calculate flow in a Cartesian domain containing a rigid sphere rotating at constant angular velocity as well as flow induced by a flapping wing. The ability of the method to simulate flows in domains with arbitrarily complex moving bodies is demonstrated by applying to simulate flow past an undulating fish-like body and flow past an anatomically realistic planktonic copepod performing an escape-like maneuver.

  8. Tensor decomposition in electronic structure calculations on 3D Cartesian grids

    SciTech Connect

    Khoromskij, B.N. Khoromskaia, V.; Chinnamsetty, S.R.; Flad, H.-J.

    2009-09-01

    In this paper, we investigate a novel approach based on the combination of Tucker-type and canonical tensor decomposition techniques for the efficient numerical approximation of functions and operators in electronic structure calculations. In particular, we study applicability of tensor approximations for the numerical solution of Hartree-Fock and Kohn-Sham equations on 3D Cartesian grids. We show that the orthogonal Tucker-type tensor approximation of electron density and Hartree potential of simple molecules leads to low tensor rank representations. This enables an efficient tensor-product convolution scheme for the computation of the Hartree potential using a collocation-type approximation via piecewise constant basis functions on a uniform nxnxn grid. Combined with the Richardson extrapolation, our approach exhibits O(h{sup 3}) convergence in the grid-size h=O(n{sup -1}). Moreover, this requires O(3rn+r{sup 3}) storage, where r denotes the Tucker rank of the electron density with r=O(logn), almost uniformly in n. For example, calculations of the Coulomb matrix and the Hartree-Fock energy for the CH{sub 4} molecule, with a pseudopotential on the C atom, achieved accuracies of the order of 10{sup -6} hartree with a grid-size n of several hundreds. Since the tensor-product convolution in 3D is performed via 1D convolution transforms, our scheme markedly outperforms the 3D-FFT in both the computing time and storage requirements.

  9. 3D Euler flow solutions using unstructured Cartesian and prismatic grids

    NASA Technical Reports Server (NTRS)

    Melton, John E.; Pandya, Shishir A.; Steger, Joseph L.

    1993-01-01

    A hyperbolic prismatic grid generation technique is combined with a background Cartesian grid for the study of inviscid three-dimensional flows. The mathematics of the hyperbolic prismatic grid generation algorithm are described, and some simple inviscid demonstration cases are presented. By combining the simplicity of the Cartesian background grid with the geometric flexibility and computational efficiencies inherent to prismatic grids, this approach shows promise for improving computational aerodynamic simulations.

  10. A fast nested dissection solver for Cartesian 3D elliptic problems using hierarchical matrices

    NASA Astrophysics Data System (ADS)

    Schmitz, Phillip G.; Ying, Lexing

    2014-02-01

    We present a fast algorithm for solutions to linear systems arising from three dimensional elliptic problems on a regular Cartesian mesh. We follow the approach of Schmitz and Ying (2012) on combining the nested dissection matrix factorization method with hierarchical matrices in two dimensions and extend it to the three dimensional case. A theoretical linear time complexity is derived and a more practical variant with slightly worse scaling is demonstrated.

  11. Electrically tunable lens speeds up 3D orbital tracking

    PubMed Central

    Annibale, Paolo; Dvornikov, Alexander; Gratton, Enrico

    2015-01-01

    3D orbital particle tracking is a versatile and effective microscopy technique that allows following fast moving fluorescent objects within living cells and reconstructing complex 3D shapes using laser scanning microscopes. We demonstrated notable improvements in the range, speed and accuracy of 3D orbital particle tracking by replacing commonly used piezoelectric stages with Electrically Tunable Lens (ETL) that eliminates mechanical movement of objective lenses. This allowed tracking and reconstructing shape of structures extending 500 microns in the axial direction. Using the ETL, we tracked at high speed fluorescently labeled genomic loci within the nucleus of living cells with unprecedented temporal resolution of 8ms using a 1.42NA oil-immersion objective. The presented technology is cost effective and allows easy upgrade of scanning microscopes for fast 3D orbital tracking. PMID:26114037

  12. Implicit Approaches for Moving Boundaries in a 3-D Cartesian Method

    NASA Technical Reports Server (NTRS)

    Murman, Scott M.; Aftosmis, Michael J.; Berger, Marsha J.; Kwak, Dochan

    2003-01-01

    This work considers numerical simulation of three-dimensional flows with time-evolving boundaries. Such problems pose a variety of challenges for numerical schemes, and have received a substantial amount of attention in the recent literature. Since such simulations are unsteady, time-accurate solution of the governing equations is required. In special cases, the body motion can be treated by a uniform rigid motion of the computational domain. For the more general situation of relative-body motion, however, this simplification is unavailable and the simulations require a mechanism for ensuring that the mesh evolves with the moving boundaries. This involves a "remeshing" of the computational domain (either localized or global) at each physical timestep, and places a premium on both the speed and robustness of the remeshing algorithms. This work presents a method which includes unsteady flow simulation, rigid domain motion, and relative body motion using a time-evolving Cartesian grid system in three dimensions.

  13. 3-D rigid body tracking using vision and depth sensors.

    PubMed

    Gedik, O Serdar; Alatan, A Aydn

    2013-10-01

    In robotics and augmented reality applications, model-based 3-D tracking of rigid objects is generally required. With the help of accurate pose estimates, it is required to increase reliability and decrease jitter in total. Among many solutions of pose estimation in the literature, pure vision-based 3-D trackers require either manual initializations or offline training stages. On the other hand, trackers relying on pure depth sensors are not suitable for AR applications. An automated 3-D tracking algorithm, which is based on fusion of vision and depth sensors via extended Kalman filter, is proposed in this paper. A novel measurement-tracking scheme, which is based on estimation of optical flow using intensity and shape index map data of 3-D point cloud, increases 2-D, as well as 3-D, tracking performance significantly. The proposed method requires neither manual initialization of pose nor offline training, while enabling highly accurate 3-D tracking. The accuracy of the proposed method is tested against a number of conventional techniques, and a superior performance is clearly observed in terms of both objectively via error metrics and subjectively for the rendered scenes. PMID:23955795

  14. Automatic respiration tracking for radiotherapy using optical 3D camera

    NASA Astrophysics Data System (ADS)

    Li, Tuotuo; Geng, Jason; Li, Shidong

    2013-03-01

    Rapid optical three-dimensional (O3D) imaging systems provide accurate digitized 3D surface data in real-time, with no patient contact nor radiation. The accurate 3D surface images offer crucial information in image-guided radiation therapy (IGRT) treatments for accurate patient repositioning and respiration management. However, applications of O3D imaging techniques to image-guided radiotherapy have been clinically challenged by body deformation, pathological and anatomical variations among individual patients, extremely high dimensionality of the 3D surface data, and irregular respiration motion. In existing clinical radiation therapy (RT) procedures target displacements are caused by (1) inter-fractional anatomy changes due to weight, swell, food/water intake; (2) intra-fractional variations from anatomy changes within any treatment session due to voluntary/involuntary physiologic processes (e.g. respiration, muscle relaxation); (3) patient setup misalignment in daily reposition due to user errors; and (4) changes of marker or positioning device, etc. Presently, viable solution is lacking for in-vivo tracking of target motion and anatomy changes during the beam-on time without exposing patient with additional ionized radiation or high magnet field. Current O3D-guided radiotherapy systems relay on selected points or areas in the 3D surface to track surface motion. The configuration of the marks or areas may change with time that makes it inconsistent in quantifying and interpreting the respiration patterns. To meet the challenge of performing real-time respiration tracking using O3D imaging technology in IGRT, we propose a new approach to automatic respiration motion analysis based on linear dimensionality reduction technique based on PCA (principle component analysis). Optical 3D image sequence is decomposed with principle component analysis into a limited number of independent (orthogonal) motion patterns (a low dimension eigen-space span by eigen-vectors). New

  15. 3D hand tracking using Kalman filter in depth space

    NASA Astrophysics Data System (ADS)

    Park, Sangheon; Yu, Sunjin; Kim, Joongrock; Kim, Sungjin; Lee, Sangyoun

    2012-12-01

    Hand gestures are an important type of natural language used in many research areas such as human-computer interaction and computer vision. Hand gestures recognition requires the prior determination of the hand position through detection and tracking. One of the most efficient strategies for hand tracking is to use 2D visual information such as color and shape. However, visual-sensor-based hand tracking methods are very sensitive when tracking is performed under variable light conditions. Also, as hand movements are made in 3D space, the recognition performance of hand gestures using 2D information is inherently limited. In this article, we propose a novel real-time 3D hand tracking method in depth space using a 3D depth sensor and employing Kalman filter. We detect hand candidates using motion clusters and predefined wave motion, and track hand locations using Kalman filter. To verify the effectiveness of the proposed method, we compare the performance of the proposed method with the visual-based method. Experimental results show that the performance of the proposed method out performs visual-based method.

  16. Monocular 3-D gait tracking in surveillance scenes.

    PubMed

    Rogez, Grégory; Rihan, Jonathan; Guerrero, Jose J; Orrite, Carlos

    2014-06-01

    Gait recognition can potentially provide a noninvasive and effective biometric authentication from a distance. However, the performance of gait recognition systems will suffer in real surveillance scenarios with multiple interacting individuals and where the camera is usually placed at a significant angle and distance from the floor. We present a methodology for view-invariant monocular 3-D human pose tracking in man-made environments in which we assume that observed people move on a known ground plane. First, we model 3-D body poses and camera viewpoints with a low dimensional manifold and learn a generative model of the silhouette from this manifold to a reduced set of training views. During the online stage, 3-D body poses are tracked using recursive Bayesian sampling conducted jointly over the scene's ground plane and the pose-viewpoint manifold. For each sample, the homography that relates the corresponding training plane to the image points is calculated using the dominant 3-D directions of the scene, the sampled location on the ground plane and the sampled camera view. Each regressed silhouette shape is projected using this homographic transformation and is matched in the image to estimate its likelihood. Our framework is able to track 3-D human walking poses in a 3-D environment exploring only a 4-D state space with success. In our experimental evaluation, we demonstrate the significant improvements of the homographic alignment over a commonly used similarity transformation and provide quantitative pose tracking results for the monocular sequences with a high perspective effect from the CAVIAR dataset. PMID:23955796

  17. 3D imaging of neutron tracks using confocal microscopy

    NASA Astrophysics Data System (ADS)

    Gillmore, Gavin; Wertheim, David; Flowers, Alan

    2016-04-01

    Neutron detection and neutron flux assessment are important aspects in monitoring nuclear energy production. Neutron flux measurements can also provide information on potential biological damage from exposure. In addition to the applications for neutron measurement in nuclear energy, neutron detection has been proposed as a method of enhancing neutrino detectors and cosmic ray flux has also been assessed using ground-level neutron detectors. Solid State Nuclear Track Detectors (or SSNTDs) have been used extensively to examine cosmic rays, long-lived radioactive elements, radon concentrations in buildings and the age of geological samples. Passive SSNTDs consisting of a CR-39 plastic are commonly used to measure radon because they respond to incident charged particles such as alpha particles from radon gas in air. They have a large dynamic range and a linear flux response. We have previously applied confocal microscopy to obtain 3D images of alpha particle tracks in SSNTDs from radon track monitoring (1). As a charged particle traverses through the polymer it creates an ionisation trail along its path. The trail or track is normally enhanced by chemical etching to better expose radiation damage, as the damaged area is more sensitive to the etchant than the bulk material. Particle tracks in CR-39 are usually assessed using 2D optical microscopy. In this study 6 detectors were examined using an Olympus OLS4100 LEXT 3D laser scanning confocal microscope (Olympus Corporation, Japan). The detectors had been etched for 2 hours 50 minutes at 85 °C in 6.25M NaOH. Post etch the plastics had been treated with a 10 minute immersion in a 2% acetic acid stop bath, followed by rinsing in deionised water. The detectors examined had been irradiated with a 2mSv neutron dose from an Am(Be) neutron source (producing roughly 20 tracks per mm2). We were able to successfully acquire 3D images of neutron tracks in the detectors studied. The range of track diameter observed was between 4

  18. Light driven micro-robotics with holographic 3D tracking

    NASA Astrophysics Data System (ADS)

    Glückstad, Jesper

    2016-04-01

    We recently pioneered the concept of light-driven micro-robotics including the new and disruptive 3D-printed micro-tools coined Wave-guided Optical Waveguides that can be real-time optically trapped and "remote-controlled" in a volume with six-degrees-of-freedom. To be exploring the full potential of this new drone-like 3D light robotics approach in challenging microscopic geometries requires a versatile and real-time reconfigurable light coupling that can dynamically track a plurality of "light robots" in 3D to ensure continuous optimal light coupling on the fly. Our latest developments in this new and exciting area will be reviewed in this invited paper.

  19. Speeding up 3D speckle tracking using PatchMatch

    NASA Astrophysics Data System (ADS)

    Zontak, Maria; O'Donnell, Matthew

    2016-03-01

    Echocardiography provides valuable information to diagnose heart dysfunction. A typical exam records several minutes of real-time cardiac images. To enable complete analysis of 3D cardiac strains, 4-D (3-D+t) echocardiography is used. This results in a huge dataset and requires effective automated analysis. Ultrasound speckle tracking is an effective method for tissue motion analysis. It involves correlation of a 3D kernel (block) around a voxel with kernels in later frames. The search region is usually confined to a local neighborhood, due to biomechanical and computational constraints. For high strains and moderate frame-rates, however, this search region will remain large, leading to a considerable computational burden. Moreover, speckle decorrelation (due to high strains) leads to errors in tracking. To solve this, spatial motion coherency between adjacent voxels should be imposed, e.g., by averaging their correlation functions.1 This requires storing correlation functions for neighboring voxels, thus increasing memory demands. In this work, we propose an efficient search using PatchMatch, 2 a powerful method to find correspondences between images. Here we adopt PatchMatch for 3D volumes and radio-frequency signals. As opposed to an exact search, PatchMatch performs random sampling of the search region and propagates successive matches among neighboring voxels. We show that: 1) Inherently smooth offset propagation in PatchMatch contributes to spatial motion coherence without any additional processing or memory demand. 2) For typical scenarios, PatchMatch is at least 20 times faster than the exact search, while maintaining comparable tracking accuracy.

  20. Tracking people and cars using 3D modeling and CCTV.

    PubMed

    Edelman, Gerda; Bijhold, Jurrien

    2010-10-10

    The aim of this study was to find a method for the reconstruction of movements of people and cars using CCTV footage and a 3D model of the environment. A procedure is proposed, in which video streams are synchronized and displayed in a 3D model, by using virtual cameras. People and cars are represented by cylinders and boxes, which are moved in the 3D model, according to their movements as shown in the video streams. The procedure was developed and tested in an experimental setup with test persons who logged their GPS coordinates as a recording of the ground truth. Results showed that it is possible to implement this procedure and to reconstruct movements of people and cars from video recordings. The procedure was also applied to a forensic case. In this work we experienced that more situational awareness was created by the 3D model, which made it easier to track people on multiple video streams. Based on all experiences from the experimental set up and the case, recommendations are formulated for use in practice. PMID:20439141

  1. Inertial Motion-Tracking Technology for Virtual 3-D

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In the 1990s, NASA pioneered virtual reality research. The concept was present long before, but, prior to this, the technology did not exist to make a viable virtual reality system. Scientists had theories and ideas they knew that the concept had potential, but the computers of the 1970s and 1980s were not fast enough, sensors were heavy and cumbersome, and people had difficulty blending fluidly with the machines. Scientists at Ames Research Center built upon the research of previous decades and put the necessary technology behind them, making the theories of virtual reality a reality. Virtual reality systems depend on complex motion-tracking sensors to convey information between the user and the computer to give the user the feeling that he is operating in the real world. These motion-tracking sensors measure and report an object s position and orientation as it changes. A simple example of motion tracking would be the cursor on a computer screen moving in correspondence to the shifting of the mouse. Tracking in 3-D, necessary to create virtual reality, however, is much more complex. To be successful, the perspective of the virtual image seen on the computer must be an accurate representation of what is seen in the real world. As the user s head or camera moves, turns, or tilts, the computer-generated environment must change accordingly with no noticeable lag, jitter, or distortion. Historically, the lack of smooth and rapid tracking of the user s motion has thwarted the widespread use of immersive 3-D computer graphics. NASA uses virtual reality technology for a variety of purposes, mostly training of astronauts. The actual missions are costly and dangerous, so any opportunity the crews have to practice their maneuvering in accurate situations before the mission is valuable and instructive. For that purpose, NASA has funded a great deal of virtual reality research, and benefited from the results.

  2. 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

  3. 3-D model-based tracking for UAV indoor localization.

    PubMed

    Teulière, Céline; Marchand, Eric; Eck, Laurent

    2015-05-01

    This paper proposes a novel model-based tracking approach for 3-D localization. One main difficulty of standard model-based approach lies in the presence of low-level ambiguities between different edges. In this paper, given a 3-D model of the edges of the environment, we derive a multiple hypotheses tracker which retrieves the potential poses of the camera from the observations in the image. We also show how these candidate poses can be integrated into a particle filtering framework to guide the particle set toward the peaks of the distribution. Motivated by the UAV indoor localization problem where GPS signal is not available, we validate the algorithm on real image sequences from UAV flights. PMID:25099967

  4. Polar versus Cartesian velocity models for maneuvering target tracking with IMM

    NASA Astrophysics Data System (ADS)

    Laneuville, Dann

    This paper compares various model sets in different IMM filters for the maneuvering target tracking problem. The aim is to see whether we can improve the tracking performance of what is certainly the most widely used model set in the literature for the maneuvering target tracking problem: a Nearly Constant Velocity model and a Nearly Coordinated Turn model. Our new challenger set consists of a mixed Cartesian position and polar velocity state vector to describe the uniform motion segments and is augmented with the turn rate to obtain the second model for the maneuvering segments. This paper also gives a general procedure to discretize up to second order any non-linear continuous time model with linear diffusion. Comparative simulations on an air defence scenario with a 2D radar, show that this new approach improves significantly the tracking performance in this case.

  5. 3D harmonic phase tracking with anatomical regularization.

    PubMed

    Zhou, Yitian; Bernard, Olivier; Saloux, Eric; Manrique, Alain; Allain, Pascal; Makram-Ebeid, Sherif; De Craene, Mathieu

    2015-12-01

    This paper presents a novel algorithm that extends HARP to handle 3D tagged MRI images. HARP results were regularized by an original regularization framework defined in an anatomical space of coordinates. In the meantime, myocardium incompressibility was integrated in order to correct the radial strain which is reported to be more challenging to recover. Both the tracking and regularization of LV displacements were done on a volumetric mesh to be computationally efficient. Also, a window-weighted regression method was extended to cardiac motion tracking which helps maintain a low complexity even at finer scales. On healthy volunteers, the tracking accuracy was found to be as accurate as the best candidates of a recent benchmark. Strain accuracy was evaluated on synthetic data, showing low bias and strain errors under 5% (excluding outliers) for longitudinal and circumferential strains, while the second and third quartiles of the radial strain errors are in the (-5%,5%) range. In clinical data, strain dispersion was shown to correlate with the extent of transmural fibrosis. Also, reduced deformation values were found inside infarcted segments. PMID:26363844

  6. 3D visualisation and analysis of single and coalescing tracks in Solid state Nuclear Track Detectors

    NASA Astrophysics Data System (ADS)

    Wertheim, David; Gillmore, Gavin; Brown, Louise; Petford, Nick

    2010-05-01

    Exposure to radon gas (222Rn) and associated ionising decay products can cause lung cancer in humans (1). Solid state Nuclear Track Detectors (SSNTDs) can be used to monitor radon concentrations (2). Radon particles form tracks in the detectors and these tracks can be etched in order to enable 2D surface image analysis. We have previously shown that confocal microscopy can be used for 3D visualisation of etched SSNTDs (3). The aim of the study was to further investigate track angles and patterns in SSNTDs. A 'LEXT' confocal laser scanning microscope (Olympus Corporation, Japan) was used to acquire 3D image datasets of five CR-39 plastic SSNTD's. The resultant 3D visualisations were analysed by eye and inclination angles assessed on selected tracks. From visual assessment, single isolated tracks as well as coalescing tracks were observed on the etched detectors. In addition varying track inclination angles were observed. Several different patterns of track formation were seen such as single isolated and double coalescing tracks. The observed track angles of inclination may help to assess the angle at which alpha particles hit the detector. Darby, S et al. Radon in homes and risk of lung cancer : collaborative analysis of individual data from 13 European case-control studies. British Medical Journal 2005; 330, 223-226. Phillips, P.S., Denman, A.R., Crockett, R.G.M., Gillmore, G., Groves-Kirkby, C.J., Woolridge, A., Comparative Analysis of Weekly vs. Three monthly radon measurements in dwellings. DEFRA Report No., DEFRA/RAS/03.006. (2004). Wertheim D, Gillmore G, Brown L, and Petford N. A new method of imaging particle tracks in Solid State Nuclear Track Detectors. Journal of Microscopy 2010; 237: 1-6.

  7. Multisensor fusion for 3D target tracking using track-before-detect particle filter

    NASA Astrophysics Data System (ADS)

    Moshtagh, Nima; Romberg, Paul M.; Chan, Moses W.

    2015-05-01

    This work presents a novel fusion mechanism for estimating the three-dimensional trajectory of a moving target using images collected by multiple imaging sensors. The proposed projective particle filter avoids the explicit target detection prior to fusion. In projective particle filter, particles that represent the posterior density (of target state in a high-dimensional space) are projected onto the lower-dimensional observation space. Measurements are generated directly in the observation space (image plane) and a marginal (sensor) likelihood is computed. The particles states and their weights are updated using the joint likelihood computed from all the sensors. The 3D state estimate of target (system track) is then generated from the states of the particles. This approach is similar to track-before-detect particle filters that are known to perform well in tracking dim and stealthy targets in image collections. Our approach extends the track-before-detect approach to 3D tracking using the projective particle filter. The performance of this measurement-level fusion method is compared with that of a track-level fusion algorithm using the projective particle filter. In the track-level fusion algorithm, the 2D sensor tracks are generated separately and transmitted to a fusion center, where they are treated as measurements to the state estimator. The 2D sensor tracks are then fused to reconstruct the system track. A realistic synthetic scenario with a boosting target was generated, and used to study the performance of the fusion mechanisms.

  8. Holographic microscopy for 3D tracking of bacteria

    NASA Astrophysics Data System (ADS)

    Nadeau, Jay; Cho, Yong Bin; El-Kholy, Marwan; Bedrossian, Manuel; Rider, Stephanie; Lindensmith, Christian; Wallace, J. Kent

    2016-03-01

    Understanding when, how, and if bacteria swim is key to understanding critical ecological and biological processes, from carbon cycling to infection. Imaging motility by traditional light microscopy is limited by focus depth, requiring cells to be constrained in z. Holographic microscopy offers an instantaneous 3D snapshot of a large sample volume, and is therefore ideal in principle for quantifying unconstrained bacterial motility. However, resolving and tracking individual cells is difficult due to the low amplitude and phase contrast of the cells; the index of refraction of typical bacteria differs from that of water only at the second decimal place. In this work we present a combination of optical and sample-handling approaches to facilitating bacterial tracking by holographic phase imaging. The first is the design of the microscope, which is an off-axis design with the optics along a common path, which minimizes alignment issues while providing all of the advantages of off-axis holography. Second, we use anti-reflective coated etalon glass in the design of sample chambers, which reduce internal reflections. Improvement seen with the antireflective coating is seen primarily in phase imaging, and its quantification is presented here. Finally, dyes may be used to increase phase contrast according to the Kramers-Kronig relations. Results using three test strains are presented, illustrating the different types of bacterial motility characterized by an enteric organism (Escherichia coli), an environmental organism (Bacillus subtilis), and a marine organism (Vibrio alginolyticus). Data processing steps to increase the quality of the phase images and facilitate tracking are also discussed.

  9. 3D whiteboard: collaborative sketching with 3D-tracked smart phones

    NASA Astrophysics Data System (ADS)

    Lue, James; Schulze, Jürgen P.

    2014-02-01

    We present the results of our investigation of the feasibility of a new approach for collaborative drawing in 3D, based on Android smart phones. Our approach utilizes a number of fiduciary markers, placed in the working area where they can be seen by the smart phones' cameras, in order to estimate the pose of each phone in the room. Our prototype allows two users to draw 3D objects with their smart phones by moving their phones around in 3D space. For example, 3D lines are drawn by recording the path of the phone as it is moved around in 3D space, drawing line segments on the screen along the way. Each user can see the virtual drawing space on their smart phones' displays, as if the display was a window into this space. Besides lines, our prototype application also supports 3D geometry creation, geometry transformation operations, and it shows the location of the other user's phone.

  10. Solwnd: A 3D Compressible MHD Code for Solar Wind Studies. Version 1.0: Cartesian Coordinates

    NASA Technical Reports Server (NTRS)

    Deane, Anil E.

    1996-01-01

    Solwnd 1.0 is a three-dimensional compressible MHD code written in Fortran for studying the solar wind. Time-dependent boundary conditions are available. The computational algorithm is based on Flux Corrected Transport and the code is based on the existing code of Zalesak and Spicer. The flow considered is that of shear flow with incoming flow that perturbs this base flow. Several test cases corresponding to pressure balanced magnetic structures with velocity shear flow and various inflows including Alfven waves are presented. Version 1.0 of solwnd considers a rectangular Cartesian geometry. Future versions of solwnd will consider a spherical geometry. Some discussions of this issue is presented.

  11. 3D track initiation in clutter using 2D measurements

    NASA Astrophysics Data System (ADS)

    Lin, Lin; Kirubarajan, Thiagalingam; Bar-Shalom, Yaakov

    2001-11-01

    In this paper we present an algorithm for initiating 3-D tracks using range and azimuth (bearing) measurements from a 2-D radar on a moving platform. The work is motivated by the need to track possibly low-flying targets, e.g., cruise missiles, using reports from an aircraft-based surveillance radar. Previous work on this problem considered simple linear motion in a flat earth coordinate frame. Our research extends this to a more realistic scenario where the earth"s curvature is also considered. The target is assumed to be moving along a great circle at a constant altitude. After the necessary coordinate transformations, the measurements are nonlinear functions of the target state and the observability of target altitude is severely limited. The observability, quantified by the Cramer-Rao Lower Bound (CRLB), is very sensitive to the sensor-to-target geometry. The paper presents a Maximum Likelihood (ML) estimator for estimating the target motion parameters in the Earth Centered Earth Fixed coordinate frame from 2-D range and angle measurements. In order to handle the possibility of false measurements and missed detections, which was not considered in, we use the Probabilistic Data Association (PDA) algorithm to weight the detections in a frame. The PDA-based modified global likelihood is optimized using a numerical search. The accuracies obtained by the resulting ML-PDA estimator are quantified using the CRLB for different sensor-target configurations. It is shown that the proposed estimator is efficient, that is, it meets the CRLB. Of particular interest is the achievable accuracy for estimating the target altitude, which is not observed directly by the 2-D radar, but can be only inferred from the range and bearing observations.

  12. 3D imaging of particle tracks in Solid State Nuclear Track Detectors

    NASA Astrophysics Data System (ADS)

    Wertheim, D.; Gillmore, G.; Brown, L.; Petford, N.

    2009-04-01

    Inhalation of radon gas (222Rn) and associated ionizing decay products is known to cause lung cancer in human. In the U.K., it has been suggested that 3 to 5 % of total lung cancer deaths can be linked to elevated radon concentrations in the home and/or workplace. Radon monitoring in buildings is therefore routinely undertaken in areas of known risk. Indeed, some organisations such as the Radon Council in the UK and the Environmental Protection Agency in the USA, advocate a ‘to test is best' policy. Radon gas occurs naturally, emanating from the decay of 238U in rock and soils. Its concentration can be measured using CR?39 plastic detectors which conventionally are assessed by 2D image analysis of the surface; however there can be some variation in outcomes / readings even in closely spaced detectors. A number of radon measurement methods are currently in use (for examples, activated carbon and electrets) but the most widely used are CR?39 solid state nuclear track?etch detectors (SSNTDs). In this technique, heavily ionizing alpha particles leave tracks in the form of radiation damage (via interaction between alpha particles and the atoms making up the CR?39 polymer). 3D imaging of the tracks has the potential to provide information relating to angle and energy of alpha particles but this could be time consuming. Here we describe a new method for rapid high resolution 3D imaging of SSNTDs. A ‘LEXT' OLS3100 confocal laser scanning microscope was used in confocal mode to successfully obtain 3D image data on four CR?39 plastic detectors. 3D visualisation and image analysis enabled characterisation of track features. This method may provide a means of rapid and detailed 3D analysis of SSNTDs. Keywords: Radon; SSNTDs; confocal laser scanning microscope; 3D imaging; LEXT

  13. Ion track reconstruction in 3D using alumina-based fluorescent nuclear track detectors.

    PubMed

    Niklas, M; Bartz, J A; Akselrod, M S; Abollahi, A; Jäkel, O; Greilich, S

    2013-09-21

    Fluorescent nuclear track detectors (FNTDs) based on Al2O3: C, Mg single crystal combined with confocal microscopy provide 3D information on ion tracks with a resolution only limited by light diffraction. FNTDs are also ideal substrates to be coated with cells to engineer cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). This radiobiological tool enables a novel platform linking cell responses to physical dose deposition on a sub-cellular level in proton and heavy ion therapies. To achieve spatial correlation between single ion hits in the cell coating and its biological response the ion traversals have to be reconstructed in 3D using the depth information gained by the FNTD read-out. FNTDs were coated with a confluent human lung adenocarcinoma epithelial (A549) cell layer. Carbon ion irradiation of the hybrid detector was performed perpendicular and angular to the detector surface. In situ imaging of the fluorescently labeled cell layer and the FNTD was performed in a sequential read-out. Making use of the trajectory information provided by the FNTD the accuracy of 3D track reconstruction of single particles traversing the hybrid detector was studied. The accuracy is strongly influenced by the irradiation angle and therefore by complexity of the FNTD signal. Perpendicular irradiation results in highest accuracy with error of smaller than 0.10°. The ability of FNTD technology to provide accurate 3D ion track reconstruction makes it a powerful tool for radiobiological investigations in clinical ion beams, either being used as a substrate to be coated with living tissue or being implanted in vivo. PMID:23965401

  14. Ion track reconstruction in 3D using alumina-based fluorescent nuclear track detectors

    NASA Astrophysics Data System (ADS)

    Niklas, M.; Bartz, J. A.; Akselrod, M. S.; Abollahi, A.; Jäkel, O.; Greilich, S.

    2013-09-01

    Fluorescent nuclear track detectors (FNTDs) based on Al2O3: C, Mg single crystal combined with confocal microscopy provide 3D information on ion tracks with a resolution only limited by light diffraction. FNTDs are also ideal substrates to be coated with cells to engineer cell-fluorescent ion track hybrid detectors (Cell-Fit-HD). This radiobiological tool enables a novel platform linking cell responses to physical dose deposition on a sub-cellular level in proton and heavy ion therapies. To achieve spatial correlation between single ion hits in the cell coating and its biological response the ion traversals have to be reconstructed in 3D using the depth information gained by the FNTD read-out. FNTDs were coated with a confluent human lung adenocarcinoma epithelial (A549) cell layer. Carbon ion irradiation of the hybrid detector was performed perpendicular and angular to the detector surface. In situ imaging of the fluorescently labeled cell layer and the FNTD was performed in a sequential read-out. Making use of the trajectory information provided by the FNTD the accuracy of 3D track reconstruction of single particles traversing the hybrid detector was studied. The accuracy is strongly influenced by the irradiation angle and therefore by complexity of the FNTD signal. Perpendicular irradiation results in highest accuracy with error of smaller than 0.10°. The ability of FNTD technology to provide accurate 3D ion track reconstruction makes it a powerful tool for radiobiological investigations in clinical ion beams, either being used as a substrate to be coated with living tissue or being implanted in vivo.

  15. 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.

  16. Multiview 3-D Echocardiography Fusion with Breath-Hold Position Tracking Using an Optical Tracking System.

    PubMed

    Punithakumar, Kumaradevan; Hareendranathan, Abhilash R; McNulty, Alexander; Biamonte, Marina; He, Allen; Noga, Michelle; Boulanger, Pierre; Becher, Harald

    2016-08-01

    Recent advances in echocardiography allow real-time 3-D dynamic image acquisition of the heart. However, one of the major limitations of 3-D echocardiography is the limited field of view, which results in an acquisition insufficient to cover the whole geometry of the heart. This study proposes the novel approach of fusing multiple 3-D echocardiography images using an optical tracking system that incorporates breath-hold position tracking to infer that the heart remains at the same position during different acquisitions. In six healthy male volunteers, 18 pairs of apical/parasternal 3-D ultrasound data sets were acquired during a single breath-hold as well as in subsequent breath-holds. The proposed method yielded a field of view improvement of 35.4 ± 12.5%. To improve the quality of the fused image, a wavelet-based fusion algorithm was developed that computes pixelwise likelihood values for overlapping voxels from multiple image views. The proposed wavelet-based fusion approach yielded significant improvement in contrast (66.46 ± 21.68%), contrast-to-noise ratio (49.92 ± 28.71%), signal-to-noise ratio (57.59 ± 47.85%) and feature count (13.06 ± 7.44%) in comparison to individual views. PMID:27166019

  17. LayTracks3D: A new approach for meshing general solids using medial axis transform

    SciTech Connect

    Quadros, William Roshan

    2015-08-22

    This study presents an extension of the all-quad meshing algorithm called LayTracks to generate high quality hex-dominant meshes of general solids. LayTracks3D uses the mapping between the Medial Axis (MA) and the boundary of the 3D domain to decompose complex 3D domains into simpler domains called Tracks. Tracks in 3D have no branches and are symmetric, non-intersecting, orthogonal to the boundary, and the shortest path from the MA to the boundary. These properties of tracks result in desired meshes with near cube shape elements at the boundary, structured mesh along the boundary normal with any irregular nodes restricted to the MA, and sharp boundary feature preservation. The algorithm has been tested on a few industrial CAD models and hex-dominant meshes are shown in the Results section. Work is underway to extend LayTracks3D to generate all-hex meshes.

  18. A 3D feature point tracking method for ion radiation.

    PubMed

    Kouwenberg, Jasper J M; Ulrich, Leonie; Jäkel, Oliver; Greilich, Steffen

    2016-06-01

    A robust and computationally efficient algorithm for automated tracking of high densities of particles travelling in (semi-) straight lines is presented. It extends the implementation of (Sbalzarini and Koumoutsakos 2005) and is intended for use in the analysis of single ion track detectors. By including information of existing tracks in the exclusion criteria and a recursive cost minimization function, the algorithm is robust to variations on the measured particle tracks. A trajectory relinking algorithm was included to resolve the crossing of tracks in high particle density images. Validation of the algorithm was performed using fluorescent nuclear track detectors (FNTD) irradiated with high- and low (heavy) ion fluences and showed less than 1% faulty trajectories in the latter. PMID:27163162

  19. A 3D feature point tracking method for ion radiation

    NASA Astrophysics Data System (ADS)

    Kouwenberg, Jasper J. M.; Ulrich, Leonie; Jäkel, Oliver; Greilich, Steffen

    2016-06-01

    A robust and computationally efficient algorithm for automated tracking of high densities of particles travelling in (semi-) straight lines is presented. It extends the implementation of (Sbalzarini and Koumoutsakos 2005) and is intended for use in the analysis of single ion track detectors. By including information of existing tracks in the exclusion criteria and a recursive cost minimization function, the algorithm is robust to variations on the measured particle tracks. A trajectory relinking algorithm was included to resolve the crossing of tracks in high particle density images. Validation of the algorithm was performed using fluorescent nuclear track detectors (FNTD) irradiated with high- and low (heavy) ion fluences and showed less than 1% faulty trajectories in the latter.

  20. pySeismicFMM: Python based travel time calculation in regular 2D and 3D grids in Cartesian and geographic coordinates using Fast Marching Method

    NASA Astrophysics Data System (ADS)

    Polkowski, Marcin

    2016-04-01

    Seismic wave travel time calculation is the most common numerical operation in seismology. The most efficient is travel time calculation in 1D velocity model - for given source, receiver depths and angular distance time is calculated within fraction of a second. Unfortunately, in most cases 1D is not enough to encounter differentiating local and regional structures. Whenever possible travel time through 3D velocity model has to be calculated. It can be achieved using ray calculation or time propagation in space. While single ray path calculation is quick it is complicated to find the ray path that connects source with the receiver. Time propagation in space using Fast Marching Method seems more efficient in most cases, especially when there are multiple receivers. In this presentation a Python module pySeismicFMM is presented - simple and very efficient tool for calculating travel time from sources to receivers. Calculation requires regular 2D or 3D velocity grid either in Cartesian or geographic coordinates. On desktop class computer calculation speed is 200k grid cells per second. Calculation has to be performed once for every source location and provides travel time to all receivers. pySeismicFMM is free and open source. Development of this tool is a part of authors PhD thesis. National Science Centre Poland provided financial support for this work via NCN grant DEC-2011/02/A/ST10/00284.

  1. A 3D diamond detector for particle tracking

    NASA Astrophysics Data System (ADS)

    Artuso, M.; Bachmair, F.; Bäni, L.; Bartosik, M.; Beacham, J.; Bellini, V.; Belyaev, V.; Bentele, B.; Berdermann, E.; Bergonzo, P.; Bes, A.; Brom, J.-M.; Bruzzi, M.; Cerv, M.; Chau, C.; Chiodini, G.; Chren, D.; Cindro, V.; Claus, G.; Collot, J.; Costa, S.; Cumalat, J.; Dabrowski, A.; D`Alessandro, R.; de Boer, W.; Dehning, B.; Dobos, D.; Dünser, M.; Eremin, V.; Eusebi, R.; Forcolin, G.; Forneris, J.; Frais-Kölbl, H.; Gan, K. K.; Gastal, M.; Goffe, M.; Goldstein, J.; Golubev, A.; Gonella, L.; Gorišek, A.; Graber, L.; Grigoriev, E.; Grosse-Knetter, J.; Gui, B.; Guthoff, M.; Haughton, I.; Hidas, D.; Hits, D.; Hoeferkamp, M.; Hofmann, T.; Hosslet, J.; Hostachy, J.-Y.; Hügging, F.; Jansen, H.; Janssen, J.; Kagan, H.; Kanxheri, K.; Kasieczka, G.; Kass, R.; Kassel, F.; Kis, M.; Kramberger, G.; Kuleshov, S.; Lacoste, A.; Lagomarsino, S.; Lo Giudice, A.; Maazouzi, C.; Mandic, I.; Mathieu, C.; McFadden, N.; McGoldrick, G.; Menichelli, M.; Mikuž, M.; Morozzi, A.; Moss, J.; Mountain, R.; Murphy, S.; Oh, A.; Olivero, P.; Parrini, G.; Passeri, D.; Pauluzzi, M.; Pernegger, H.; Perrino, R.; Picollo, F.; Pomorski, M.; Potenza, R.; Quadt, A.; Re, A.; Riley, G.; Roe, S.; Sapinski, M.; Scaringella, M.; Schnetzer, S.; Schreiner, T.; Sciortino, S.; Scorzoni, A.; Seidel, S.; Servoli, L.; Sfyrla, A.; Shimchuk, G.; Smith, D. S.; Sopko, B.; Sopko, V.; Spagnolo, S.; Spanier, S.; Stenson, K.; Stone, R.; Sutera, C.; Taylor, A.; Traeger, M.; Tromson, D.; Trischuk, W.; Tuve, C.; Uplegger, L.; Velthuis, J.; Venturi, N.; Vittone, E.; Wagner, S.; Wallny, R.; Wang, J. C.; Weilhammer, P.; Weingarten, J.; Weiss, C.; Wengler, T.; Wermes, N.; Yamouni, M.; Zavrtanik, M.

    2016-07-01

    In the present study, results towards the development of a 3D diamond sensor are presented. Conductive channels are produced inside the sensor bulk using a femtosecond laser. This electrode geometry allows full charge collection even for low quality diamond sensors. Results from testbeam show that charge is collected by these electrodes. In order to understand the channel growth parameters, with the goal of producing low resistivity channels, the conductive channels produced with a different laser setup are evaluated by Raman spectroscopy.

  2. 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

  3. THE THOMSON SURFACE. III. TRACKING FEATURES IN 3D

    SciTech Connect

    Howard, T. A.; DeForest, C. E.; Tappin, S. J.; Odstrcil, D.

    2013-03-01

    In this, the final installment in a three-part series on the Thomson surface, we present simulated observations of coronal mass ejections (CMEs) observed by a hypothetical polarizing white light heliospheric imager. Thomson scattering yields a polarization signal that can be exploited to locate observed features in three dimensions relative to the Thomson surface. We consider how the appearance of the CME changes with the direction of trajectory, using simulations of a simple geometrical shape and also of a more realistic CME generated using the ENLIL model. We compare the appearance in both unpolarized B and polarized pB light, and show that there is a quantifiable difference in the measured brightness of a CME between unpolarized and polarized observations. We demonstrate a technique for using this difference to extract the three-dimensional (3D) trajectory of large objects such as CMEs. We conclude with a discussion on how a polarizing heliospheric imager could be used to extract 3D trajectory information about CMEs or other observed features.

  4. 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.

  5. Preparation and 3D Tracking of Catalytic Swimming Devices.

    PubMed

    Campbell, Andrew; Archer, Richard; Ebbens, Stephen

    2016-01-01

    We report a method to prepare catalytically active Janus colloids that "swim" in fluids and describe how to determine their 3D motion using fluorescence microscopy. One commonly deployed method for catalytically active colloids to produce enhanced motion is via an asymmetrical distribution of catalyst. Here this is achieved by spin coating a dispersed layer of fluorescent polymeric colloids onto a flat planar substrate, and then using directional platinum vapor deposition to half coat the exposed colloid surface, making a two faced "Janus" structure. The Janus colloids are then re-suspended from the planar substrate into an aqueous solution containing hydrogen peroxide. Hydrogen peroxide serves as a fuel for the platinum catalyst, which is decomposed into water and oxygen, but only on one side of the colloid. The asymmetry results in gradients that produce enhanced motion, or "swimming". A fluorescence microscope, together with a video camera is used to record the motion of individual colloids. The center of the fluorescent emission is found using image analysis to provide an x and y coordinate for each frame of the video. While keeping the microscope focal position fixed, the fluorescence emission from the colloid produces a characteristic concentric ring pattern which is subject to image analysis to determine the particles relative z position. In this way 3D trajectories for the swimming colloid are obtained, allowing swimming velocity to be accurately measured, and physical phenomena such as gravitaxis, which may bias the colloids motion to be detected. PMID:27404327

  6. A non-disruptive technology for robust 3D tool tracking for ultrasound-guided interventions.

    PubMed

    Mung, Jay; Vignon, Francois; Jain, Ameet

    2011-01-01

    In the past decade ultrasound (US) has become the preferred modality for a number of interventional procedures, offering excellent soft tissue visualization. The main limitation however is limited visualization of surgical tools. A new method is proposed for robust 3D tracking and US image enhancement of surgical tools under US guidance. Small US sensors are mounted on existing surgical tools. As the imager emits acoustic energy, the electrical signal from the sensor is analyzed to reconstruct its 3D coordinates. These coordinates can then be used for 3D surgical navigation, similar to current day tracking systems. A system with real-time 3D tool tracking and image enhancement was implemented on a commercial ultrasound scanner and 3D probe. Extensive water tank experiments with a tracked 0.2mm sensor show robust performance in a wide range of imaging conditions and tool position/orientations. The 3D tracking accuracy was 0.36 +/- 0.16mm throughout the imaging volume of 55 degrees x 27 degrees x 150mm. Additionally, the tool was successfully tracked inside a beating heart phantom. This paper proposes an image enhancement and tool tracking technology with sub-mm accuracy for US-guided interventions. The technology is non-disruptive, both in terms of existing clinical workflow and commercial considerations, showing promise for large scale clinical impact. PMID:22003612

  7. Modeling cell migration on filamentous tracks in 3D

    NASA Astrophysics Data System (ADS)

    Schwarz, J. M.

    2014-03-01

    Cell motility is integral to a number of physiological processes ranging from wound healing to immune response to cancer metastasis. Many studies of cell migration, both experimental and theoretical, have addressed various aspects of it in two dimensions, including protrusion and retraction at the level of single cells. However, the in vivo environment for a crawling cell is typically a three-dimensional environment, consisting of the extracellular matrix (ECM) and surrounding cells. Recent experiments demonstrate that some cells crawling along fibers of the ECM mimic the geometry of the fibers to become long and thin, as opposed to fan-like in two dimensions, and can remodel the ECM. Inspired by these experiments, a model cell consisting of beads and springs that moves along a tense semiflexible filamentous track is constructed and studied, paying particular attention to the mechanical feedback between the model cell and the track, as mediated by the active myosin-driven contractility and the catch/slip bond behavior of the focal adhesions, as the model cell crawls. This simple construction can then be scaled up to a model cell moving along a three-dimensional filamentous network, with a prescribed microenvironment, in order to make predictions for proposed experiments.

  8. Tracking 3-D body motion for docking and robot control

    NASA Technical Reports Server (NTRS)

    Donath, M.; Sorensen, B.; Yang, G. B.; Starr, R.

    1987-01-01

    An advanced method of tracking three-dimensional motion of bodies has been developed. This system has the potential to dynamically characterize machine and other structural motion, even in the presence of structural flexibility, thus facilitating closed loop structural motion control. The system's operation is based on the concept that the intersection of three planes defines a point. Three rotating planes of laser light, fixed and moving photovoltaic diode targets, and a pipe-lined architecture of analog and digital electronics are used to locate multiple targets whose number is only limited by available computer memory. Data collection rates are a function of the laser scan rotation speed and are currently selectable up to 480 Hz. The tested performance on a preliminary prototype designed for 0.1 in accuracy (for tracking human motion) at a 480 Hz data rate includes a worst case resolution of 0.8 mm (0.03 inches), a repeatability of plus or minus 0.635 mm (plus or minus 0.025 inches), and an absolute accuracy of plus or minus 2.0 mm (plus or minus 0.08 inches) within an eight cubic meter volume with all results applicable at the 95 percent level of confidence along each coordinate region. The full six degrees of freedom of a body can be computed by attaching three or more target detectors to the body of interest.

  9. Track of Right-Wheel Drag (3-D)

    NASA Technical Reports Server (NTRS)

    2004-01-01

    [figure removed for brevity, see original site] Figure 1

    [figure removed for brevity, see original site] Figure 2

    This 360-degree stereo panorama combines several frames taken by the navigation camera on NASA's Mars Exploration Rover Spirit during the rover's 313th martian day (Nov. 19, 2004). The site, labeled Spirit site 93, is in the 'Columbia Hills' inside Gusev Crater. The rover tracks point westward. Spirit had driven eastward, in reverse and dragging its right front wheel, for about 30 meters (100 feet) on the day the picture was taken. Driving backwards while dragging that wheel is a precautionary strategy to extend the usefulness of the wheel for when it is most needed, because it has developed more friction than the other wheels. The right-hand track in this look backwards shows how the dragging disturbed the soil. This view is presented in a cylindrical-perspective projection with geometric seam correction.

    Figure 1 is the left-eye view of a stereo pair and Figure 2 is the right-eye view of a stereo pair.

  10. 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.

  11. A new 3D tracking method exploiting the capabilities of digital holography in microscopy

    NASA Astrophysics Data System (ADS)

    Miccio, L.; Memmolo, P.; Merola, F.; Fusco, S.; Embrione, V.; Netti, P. A.; Ferraro, P.

    2013-04-01

    A method for 3D tracking has been developed exploiting Digital Holographic Microscopy (DHM) features. In the framework of self-consistent platform for manipulation and measurement of biological specimen we use DHM for quantitative and completely label free analysis of specimen with low amplitude contrast. Tracking capability extend the potentiality of DHM allowing to monitor the motion of appropriate probes and correlate it with sample properties. Complete 3D tracking has been obtained for the probes avoiding the issue of amplitude refocusing in traditional tracking processing. Our technique belongs to the video tracking methods that, conversely from Quadrant Photo-Diode method, opens the possibility to track multiples probes. All the common used video tracking algorithms are based on the numerical analysis of amplitude images in the focus plane and the shift of the maxima in the image plane are measured after the application of an appropriate threshold. Our approach for video tracking uses different theoretical basis. A set of interferograms is recorded and the complex wavefields are managed numerically to obtain three dimensional displacements of the probes. The procedure works properly on an higher number of probes and independently from their size. This method overcomes the traditional video tracking issues as the inability to measure the axial movement and the choice of suitable threshold mask. The novel configuration allows 3D tracking of micro-particles and simultaneously can furnish Quantitative Phase-contrast maps of tracked micro-objects by interference microscopy, without changing the configuration. In this paper, we show a new concept for a compact interferometric microscope that can ensure the multifunctionality, accomplishing accurate 3D tracking and quantitative phase-contrast analysis. Experimental results are presented and discussed for in vitro cells. Through a very simple and compact optical arrangement we show how two different functionalities

  12. LV motion tracking from 3D echocardiography using textural and structural information.

    PubMed

    Myronenko, Andriy; Song, Xubo; Sahn, David J

    2007-01-01

    Automated motion reconstruction of the left ventricle (LV) from 3D echocardiography provides insight into myocardium architecture and function. Low image quality and artifacts make 3D ultrasound image processing a challenging problem. We introduce a LV tracking method, which combines textural and structural information to overcome the image quality limitations. Our method automatically reconstructs the motion of the LV contour (endocardium and epicardium) from a sequence of 3D ultrasound images. PMID:18044597

  13. Fast and accurate global multiphase arrival tracking: the irregular shortest-path method in a 3-D spherical earth model

    NASA Astrophysics Data System (ADS)

    Huang, Guo-Jiao; Bai, Chao-Ying; Greenhalgh, Stewart

    2013-09-01

    The traditional grid/cell-based wavefront expansion algorithms, such as the shortest path algorithm, can only find the first arrivals or multiply reflected (or mode converted) waves transmitted from subsurface interfaces, but cannot calculate the other later reflections/conversions having a minimax time path. In order to overcome the above limitations, we introduce the concept of a stationary minimax time path of Fermat's Principle into the multistage irregular shortest path method. Here we extend it from Cartesian coordinates for a flat earth model to global ray tracing of multiple phases in a 3-D complex spherical earth model. The ray tracing results for 49 different kinds of crustal, mantle and core phases show that the maximum absolute traveltime error is less than 0.12 s and the average absolute traveltime error is within 0.09 s when compared with the AK135 theoretical traveltime tables for a 1-D reference model. Numerical tests in terms of computational accuracy and CPU time consumption indicate that the new scheme is an accurate, efficient and a practical way to perform 3-D multiphase arrival tracking in regional or global traveltime tomography.

  14. 3D deformable organ model based liver motion tracking in ultrasound videos

    NASA Astrophysics Data System (ADS)

    Kim, Jung-Bae; Hwang, Youngkyoo; Oh, Young-Taek; Bang, Won-Chul; Lee, Heesae; Kim, James D. K.; Kim, Chang Yeong

    2013-03-01

    This paper presents a novel method of using 2D ultrasound (US) cine images during image-guided therapy to accurately track the 3D position of a tumor even when the organ of interest is in motion due to patient respiration. Tracking is possible thanks to a 3D deformable organ model we have developed. The method consists of three processes in succession. The first process is organ modeling where we generate a personalized 3D organ model from high quality 3D CT or MR data sets captured during three different respiratory phases. The model includes the organ surface, vessel and tumor, which can all deform and move in accord with patient respiration. The second process is registration of the organ model to 3D US images. From 133 respiratory phase candidates generated from the deformable organ model, we resolve the candidate that best matches the 3D US images according to vessel centerline and surface. As a result, we can determine the position of the US probe. The final process is real-time tracking using 2D US cine images captured by the US probe. We determine the respiratory phase by tracking the diaphragm on the image. The 3D model is then deformed according to respiration phase and is fitted to the image by considering the positions of the vessels. The tumor's 3D positions are then inferred based on respiration phase. Testing our method on real patient data, we have found the accuracy of 3D position is within 3.79mm and processing time is 5.4ms during tracking.

  15. 3D model-based catheter tracking for motion compensation in EP procedures

    NASA Astrophysics Data System (ADS)

    Brost, Alexander; Liao, Rui; Hornegger, Joachim; Strobel, Norbert

    2010-02-01

    Atrial fibrillation is the most common sustained heart arrhythmia and a leading cause of stroke. Its treatment by radio-frequency catheter ablation, performed using fluoroscopic image guidance, is gaining increasingly more importance. Two-dimensional fluoroscopic navigation can take advantage of overlay images derived from pre-operative 3-D data to add anatomical details otherwise not visible under X-ray. Unfortunately, respiratory motion may impair the utility of these static overlay images for catheter navigation. We developed an approach for image-based 3-D motion compensation as a solution to this problem. A bi-plane C-arm system is used to take X-ray images of a special circumferential mapping catheter from two directions. In the first step of the method, a 3-D model of the device is reconstructed. Three-dimensional respiratory motion at the site of ablation is then estimated by tracking the reconstructed catheter model in 3-D. This step involves bi-plane fluoroscopy and 2-D/3-D registration. Phantom data and clinical data were used to assess our model-based catheter tracking method. Experiments involving a moving heart phantom yielded an average 2-D tracking error of 1.4 mm and an average 3-D tracking error of 1.1 mm. Our evaluation of clinical data sets comprised 469 bi-plane fluoroscopy frames (938 monoplane fluoroscopy frames). We observed an average 2-D tracking error of 1.0 mm +/- 0.4 mm and an average 3-D tracking error of 0.8 mm +/- 0.5 mm. These results demonstrate that model-based motion-compensation based on 2-D/3-D registration is both feasible and accurate.

  16. LayTracks3D: A new approach for meshing general solids using medial axis transform

    DOE PAGESBeta

    Quadros, William Roshan

    2015-08-22

    This study presents an extension of the all-quad meshing algorithm called LayTracks to generate high quality hex-dominant meshes of general solids. LayTracks3D uses the mapping between the Medial Axis (MA) and the boundary of the 3D domain to decompose complex 3D domains into simpler domains called Tracks. Tracks in 3D have no branches and are symmetric, non-intersecting, orthogonal to the boundary, and the shortest path from the MA to the boundary. These properties of tracks result in desired meshes with near cube shape elements at the boundary, structured mesh along the boundary normal with any irregular nodes restricted to themore » MA, and sharp boundary feature preservation. The algorithm has been tested on a few industrial CAD models and hex-dominant meshes are shown in the Results section. Work is underway to extend LayTracks3D to generate all-hex meshes.« less

  17. Sketch on dynamic gesture tracking and analysis exploiting vision-based 3D interface

    NASA Astrophysics Data System (ADS)

    Woo, Woontack; Kim, Namgyu; Wong, Karen; Tadenuma, Makoto

    2000-12-01

    In this paper, we propose a vision-based 3D interface exploiting invisible 3D boxes, arranged in the personal space (i.e. reachable space by the body without traveling), which allows robust yet simple dynamic gesture tracking and analysis, without exploiting complicated sensor-based motion tracking systems. Vision-based gesture tracking and analysis is still a challenging problem, even though we have witnessed rapid advances in computer vision over the last few decades. The proposed framework consists of three main parts, i.e. (1) object segmentation without bluescreen and 3D box initialization with depth information, (2) movement tracking by observing how the body passes through the 3D boxes in the personal space and (3) movement feature extraction based on Laban's Effort theory and movement analysis by mapping features to meaningful symbols using time-delay neural networks. Obviously, exploiting depth information using multiview images improves the performance of gesture analysis by reducing the errors introduced by simple 2D interfaces In addition, the proposed box-based 3D interface lessens the difficulties in both tracking movement in 3D space and in extracting low-level features of the movement. Furthermore, the time-delay neural networks lessens the difficulties in movement analysis by training. Due to its simplicity and robustness, the framework will provide interactive systems, such as ATR I-cubed Tangible Music System or ATR Interactive Dance system, with improved quality of the 3D interface. The proposed simple framework also can be extended to other applications requiring dynamic gesture tracking and analysis on the fly.

  18. Nearly automatic motion capture system for tracking octopus arm movements in 3D space.

    PubMed

    Zelman, Ido; Galun, Meirav; Akselrod-Ballin, Ayelet; Yekutieli, Yoram; Hochner, Binyamin; Flash, Tamar

    2009-08-30

    Tracking animal movements in 3D space is an essential part of many biomechanical studies. The most popular technique for human motion capture uses markers placed on the skin which are tracked by a dedicated system. However, this technique may be inadequate for tracking animal movements, especially when it is impossible to attach markers to the animal's body either because of its size or shape or because of the environment in which the animal performs its movements. Attaching markers to an animal's body may also alter its behavior. Here we present a nearly automatic markerless motion capture system that overcomes these problems and successfully tracks octopus arm movements in 3D space. The system is based on three successive tracking and processing stages. The first stage uses a recently presented segmentation algorithm to detect the movement in a pair of video sequences recorded by two calibrated cameras. In the second stage, the results of the first stage are processed to produce 2D skeletal representations of the moving arm. Finally, the 2D skeletons are used to reconstruct the octopus arm movement as a sequence of 3D curves varying in time. Motion tracking, segmentation and reconstruction are especially difficult problems in the case of octopus arm movements because of the deformable, non-rigid structure of the octopus arm and the underwater environment in which it moves. Our successful results suggest that the motion-tracking system presented here may be used for tracking other elongated objects. PMID:19505502

  19. Computational Graph Model for 3D Cells Tracking in Zebra Fish Datasets

    NASA Astrophysics Data System (ADS)

    Zhang, Lelin; Xiong, Hongkai; Zhao, Yang; Zhang, Kai; Zhou, Xiaobo

    2007-11-01

    This paper leads to a novel technique for tracking and identification of zebra-fish cells in 3D image sequences, extending graph-based multi-objects tracking algorithm to 3D applications. As raised in previous work of 2D graph-based method, separated cells are modeled as vertices that connected by edges. Then the tracking work is simplified to that of vertices matching between graphs generated from consecutive frames. Graph-based tracking is composed of three steps: graph generation, initial source vertices selection and graph saturation. To satisfy demands in this work separated cell records are segmented from original datasets using 3D level-set algorithms. Besides, advancements are achieved in each of the step including graph regulations, multi restrictions on source vertices and enhanced flow quantifications. Those strategies make a good compensation for graph-based multi-objects tracking method in 2D space. Experiments are carried out in 3D datasets sampled from zebra fish, results of which shows that this enhanced method could be potentially applied to tracking of objects with diverse features.

  20. High-throughput 3D tracking of bacteria on a standard phase contrast microscope

    NASA Astrophysics Data System (ADS)

    Taute, K. M.; Gude, S.; Tans, S. J.; Shimizu, T. S.

    2015-11-01

    Bacteria employ diverse motility patterns in traversing complex three-dimensional (3D) natural habitats. 2D microscopy misses crucial features of 3D behaviour, but the applicability of existing 3D tracking techniques is constrained by their performance or ease of use. Here we present a simple, broadly applicable, high-throughput 3D bacterial tracking method for use in standard phase contrast microscopy. Bacteria are localized at micron-scale resolution over a range of 350 × 300 × 200 μm by maximizing image cross-correlations between their observed diffraction patterns and a reference library. We demonstrate the applicability of our technique to a range of bacterial species and exploit its high throughput to expose hidden contributions of bacterial individuality to population-level variability in motile behaviour. The simplicity of this powerful new tool for bacterial motility research renders 3D tracking accessible to a wider community and paves the way for investigations of bacterial motility in complex 3D environments.

  1. High-throughput 3D tracking of bacteria on a standard phase contrast microscope

    PubMed Central

    Taute, K.M.; Gude, S.; Tans, S.J.; Shimizu, T.S.

    2015-01-01

    Bacteria employ diverse motility patterns in traversing complex three-dimensional (3D) natural habitats. 2D microscopy misses crucial features of 3D behaviour, but the applicability of existing 3D tracking techniques is constrained by their performance or ease of use. Here we present a simple, broadly applicable, high-throughput 3D bacterial tracking method for use in standard phase contrast microscopy. Bacteria are localized at micron-scale resolution over a range of 350 × 300 × 200 μm by maximizing image cross-correlations between their observed diffraction patterns and a reference library. We demonstrate the applicability of our technique to a range of bacterial species and exploit its high throughput to expose hidden contributions of bacterial individuality to population-level variability in motile behaviour. The simplicity of this powerful new tool for bacterial motility research renders 3D tracking accessible to a wider community and paves the way for investigations of bacterial motility in complex 3D environments. PMID:26522289

  2. Tracking 3D Picometer-Scale Motions of Single Nanoparticles with High-Energy Electron Probes

    PubMed Central

    Ogawa, Naoki; Hoshisashi, Kentaro; Sekiguchi, Hiroshi; Ichiyanagi, Kouhei; Matsushita, Yufuku; Hirohata, Yasuhisa; Suzuki, Seiichi; Ishikawa, Akira; Sasaki, Yuji C.

    2013-01-01

    We observed the high-speed anisotropic motion of an individual gold nanoparticle in 3D at the picometer scale using a high-energy electron probe. Diffracted electron tracking (DET) using the electron back-scattered diffraction (EBSD) patterns of labeled nanoparticles under wet-SEM allowed us to super-accurately measure the time-resolved 3D motion of individual nanoparticles in aqueous conditions. The highly precise DET data corresponded to the 3D anisotropic log-normal Gaussian distributions over time at the millisecond scale. PMID:23868465

  3. Detailed Evaluation of Five 3D Speckle Tracking Algorithms Using Synthetic Echocardiographic Recordings.

    PubMed

    Alessandrini, Martino; Heyde, Brecht; Queiros, Sandro; Cygan, Szymon; Zontak, Maria; Somphone, Oudom; Bernard, Olivier; Sermesant, Maxime; Delingette, Herve; Barbosa, Daniel; De Craene, Mathieu; ODonnell, Matthew; Dhooge, Jan

    2016-08-01

    A plethora of techniques for cardiac deformation imaging with 3D ultrasound, typically referred to as 3D speckle tracking techniques, are available from academia and industry. Although the benefits of single methods over alternative ones have been reported in separate publications, the intrinsic differences in the data and definitions used makes it hard to compare the relative performance of different solutions. To address this issue, we have recently proposed a framework to simulate realistic 3D echocardiographic recordings and used it to generate a common set of ground-truth data for 3D speckle tracking algorithms, which was made available online. The aim of this study was therefore to use the newly developed database to contrast non-commercial speckle tracking solutions from research groups with leading expertise in the field. The five techniques involved cover the most representative families of existing approaches, namely block-matching, radio-frequency tracking, optical flow and elastic image registration. The techniques were contrasted in terms of tracking and strain accuracy. The feasibility of the obtained strain measurements to diagnose pathology was also tested for ischemia and dyssynchrony. PMID:26960220

  4. Vision-Based Long-Range 3D Tracking, applied to Underground Surveying Tasks

    NASA Astrophysics Data System (ADS)

    Mossel, Annette; Gerstweiler, Georg; Vonach, Emanuel; Kaufmann, Hannes; Chmelina, Klaus

    2014-04-01

    To address the need of highly automated positioning systems in underground construction, we present a long-range 3D tracking system based on infrared optical markers. It provides continuous 3D position estimation of static or kinematic targets with low latency over a tracking volume of 12 m x 8 m x 70 m (width x height x depth). Over the entire volume, relative 3D point accuracy with a maximal deviation ≤ 22 mm is ensured with possible target rotations of yaw, pitch = 0 - 45° and roll = 0 - 360°. No preliminary sighting of target(s) is necessary since the system automatically locks onto a target without user intervention and autonomously starts tracking as soon as a target is within the view of the system. The proposed system needs a minimal hardware setup, consisting of two machine vision cameras and a standard workstation for data processing. This allows for quick installation with minimal disturbance of construction work. The data processing pipeline ensures camera calibration and tracking during on-going underground activities. Tests in real underground scenarios prove the system's capabilities to act as 3D position measurement platform for multiple underground tasks that require long range, low latency and high accuracy. Those tasks include simultaneously tracking of personnel, machines or robots.

  5. 3D target tracking in infrared imagery by SIFT-based distance histograms

    NASA Astrophysics Data System (ADS)

    Yan, Ruicheng; Cao, Zhiguo

    2011-11-01

    SIFT tracking algorithm is an excellent point-based tracking algorithm, which has high tracking performance and accuracy due to its robust capability against rotation, scale change and occlusion. However, when tracking a huge 3D target in complicated real scenarios in a forward-looking infrared (FLIR) image sequence taken from an airborne moving platform, the tracked point locating in the vertical surface usually shifts away from the correct position. In this paper, we propose a novel algorithm for 3D target tracking in FLIR image sequences. Our approach uses SIFT keypoints detected in consecutive frames for point correspondence. The candidate position of the tracked point is firstly estimated by computing the affine transformation using local corresponding SIFT keypoints. Then the correct position is located via an optimal method. Euclidean distances between a candidate point and SIFT keypoints nearby are calculated and formed into a SIFT-based distance histogram. The distance histogram is defined a cost of associating each candidate point to a correct tracked point using the constraint based on the topology of each candidate point with its surrounding SIFT keypoints. Minimization of the cost is formulated as a combinatorial optimization problem. Experiments demonstrate that the proposed algorithm efficiently improves the tracking performance and accuracy.

  6. 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.

  7. Rapid 3D Track Reconstruction with the BaBar Trigger Upgrade

    SciTech Connect

    Bailey, S

    2004-05-24

    As the PEP-II luminosity increases the BaBar trigger and dataflow systems must accommodate the increasing data rate. A significant source of background events at the first trigger level comes from beam particle interactions with the beampipe and synchrotron masks, which are separated from the interaction region by more than 20 cm. The BaBar trigger upgrade will provide 3D tracking capabilities at the first trigger level in order to remove background events by distinguishing the origin of particle tracks. Each new z{sub 0} p{sub T} Discriminator (ZPD) board processes over 1 gigabyte of data per second in order to reconstruct the tracks and make trigger decisions based upon the 3D track parameters.

  8. 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.

  9. Towards 3D ultrasound image based soft tissue tracking: a transrectal ultrasound prostate image alignment system.

    PubMed

    Baumann, Michael; Mozer, Pierre; Daanen, Vincent; Troccaz, Jocelyne

    2007-01-01

    The emergence of real-time 3D ultrasound (US) makes it possible to consider image-based tracking of subcutaneous soft tissue targets for computer guided diagnosis and therapy. We propose a 3D transrectal US based tracking system for precise prostate biopsy sample localisation. The aim is to improve sample distribution, to enable targeting of unsampled regions for repeated biopsies, and to make post-interventional quality controls possible. Since the patient is not immobilized, since the prostate is mobile and due to the fact that probe movements are only constrained by the rectum during biopsy acquisition, the tracking system must be able to estimate rigid transformations that are beyond the capture range of common image similarity measures. We propose a fast and robust multi-resolution attribute-vector registration approach that combines global and local optimization methods to solve this problem. Global optimization is performed on a probe movement model that reduces the dimensionality of the search space and thus renders optimization efficient. The method was tested on 237 prostate volumes acquired from 14 different patients for 3D to 3D and 3D to orthogonal 2D slices registration. The 3D-3D version of the algorithm converged correctly in 96.7% of all cases in 6.5s with an accuracy of 1.41mm (r.m.s.) and 3.84mm (max). The 3D to slices method yielded a success rate of 88.9% in 2.3s with an accuracy of 1.37mm (r.m.s.) and 4.3mm (max). PMID:18044549

  10. 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".

  11. Moving Human Path Tracking Based on Video Surveillance in 3d Indoor Scenarios

    NASA Astrophysics Data System (ADS)

    Zhou, Yan; Zlatanova, Sisi; Wang, Zhe; Zhang, Yeting; Liu, Liu

    2016-06-01

    Video surveillance systems are increasingly used for a variety of 3D indoor applications. We can analyse human behaviour, discover and avoid crowded areas, monitor human traffic and so forth. In this paper we concentrate on use of surveillance cameras to track and reconstruct the path a person has followed. For the purpose we integrated video surveillance data with a 3D indoor model of the building and develop a single human moving path tracking method. We process the surveillance videos to detected single human moving traces; then we match the depth information of 3D scenes to the constructed 3D indoor network model and define the human traces in the 3D indoor space. Finally, the single human traces extracted from multiple cameras are connected with the help of the connectivity provided by the 3D network model. Using this approach, we can reconstruct the entire walking path. The provided experiments with a single person have verified the effectiveness and robustness of the method.

  12. A full-parallax 3D display with restricted viewing zone tracking viewer's eye

    NASA Astrophysics Data System (ADS)

    Beppu, Naoto; Yendo, Tomohiro

    2015-03-01

    The Three-Dimensional (3D) vision became widely known as familiar imaging technique now. The 3D display has been put into practical use in various fields, such as entertainment and medical fields. Development of 3D display technology will play an important role in a wide range of fields. There are various ways to the method of displaying 3D image. There is one of the methods that showing 3D image method to use the ray reproduction and we focused on it. This method needs many viewpoint images when achieve a full-parallax because this method display different viewpoint image depending on the viewpoint. We proposed to reduce wasteful rays by limiting projector's ray emitted to around only viewer using a spinning mirror, and to increase effectiveness of display device to achieve a full-parallax 3D display. We propose a method by using a tracking viewer's eye, a high-speed projector, a rotating mirror that tracking viewer (a spinning mirror), a concave mirror array having the different vertical slope arranged circumferentially (a concave mirror array), a cylindrical mirror. About proposed method in simulation, we confirmed the scanning range and the locus of the movement in the horizontal direction of the ray. In addition, we confirmed the switching of the viewpoints and convergence performance in the vertical direction of rays. Therefore, we confirmed that it is possible to realize a full-parallax.

  13. The BaBar Level 1 Drift-Chamber Trigger Upgrade With 3D Tracking

    SciTech Connect

    Chai, X.D.; /Iowa U.

    2005-11-29

    At BABAR, the Level 1 Drift Chamber trigger is being upgraded to reduce increasing background rates while the PEP-II luminosity keeps improving. This upgrade uses the drift time information and stereo wires in the drift chamber to perform a 3D track reconstruction that effectively rejects background events spread out along the beam line.

  14. 3D single molecule tracking in thick cellular specimens using multifocal plane microscopy

    NASA Astrophysics Data System (ADS)

    Ram, Sripad; Ward, E. Sally; Ober, Raimund J.

    2011-03-01

    One of the major challenges in single molecule microscopy concerns 3D tracking of single molecules in cellular specimens. This has been a major impediment to study many fundamental cellular processes, such as protein transport across thick cellular specimens (e.g. a cell-monolayer). Here we show that multifocal plane microscopy (MUM), an imaging modality developed by our group, provides the much needed solution to this longstanding problem. While MUM was previously used for 3D single molecule tracking at shallow depths (~ 1 micron) in live-cells, the question arises if MUM can also live up to the significant challenge of tracking single molecules in thick samples. Here by substantially expanding the capabilities of MUM, we demonstrate 3D tracking of quantum-dot labeled molecules in a ~ 10 micron thick cell monolayer. In this way we have reconstructed the complete 3D intracellular trafficking itinerary of single molecules at high spatial and temporal precision in a thick cell-sample. Funding support: NIH and the National MS Society.

  15. Mesoscopic in vivo 3-D tracking of sparse cell populations using angular multiplexed optical projection tomography

    PubMed Central

    Chen, Lingling; Alexandrov, Yuriy; Kumar, Sunil; Andrews, Natalie; Dallman, Margaret J.; French, Paul M. W.; McGinty, James

    2015-01-01

    We describe an angular multiplexed imaging technique for 3-D in vivo cell tracking of sparse cell distributions and optical projection tomography (OPT) with superior time-lapse resolution and a significantly reduced light dose compared to volumetric time-lapse techniques. We demonstrate that using dual axis OPT, where two images are acquired simultaneously at different projection angles, can enable localization and tracking of features in 3-D with a time resolution equal to the camera frame rate. This is achieved with a 200x reduction in light dose compared to an equivalent volumetric time-lapse single camera OPT acquisition with 200 projection angles. We demonstrate the application of this technique to mapping the 3-D neutrophil migration pattern observed over ~25.5 minutes in a live 2 day post-fertilisation transgenic LysC:GFP zebrafish embryo following a tail wound. PMID:25909009

  16. Particle Filters and Occlusion Handling for Rigid 2D-3D Pose Tracking.

    PubMed

    Lee, Jehoon; Sandhu, Romeil; Tannenbaum, Allen

    2013-08-01

    In this paper, we address the problem of 2D-3D pose estimation. Specifically, we propose an approach to jointly track a rigid object in a 2D image sequence and to estimate its pose (position and orientation) in 3D space. We revisit a joint 2D segmentation/3D pose estimation technique, and then extend the framework by incorporating a particle filter to robustly track the object in a challenging environment, and by developing an occlusion detection and handling scheme to continuously track the object in the presence of occlusions. In particular, we focus on partial occlusions that prevent the tracker from extracting an exact region properties of the object, which plays a pivotal role for region-based tracking methods in maintaining the track. To this end, a dynamical choice of how to invoke the objective functional is performed online based on the degree of dependencies between predictions and measurements of the system in accordance with the degree of occlusion and the variation of the object's pose. This scheme provides the robustness to deal with occlusions of an obstacle with different statistical properties from that of the object of interest. Experimental results demonstrate the practical applicability and robustness of the proposed method in several challenging scenarios. PMID:24058277

  17. 3D model-based detection and tracking for space autonomous and uncooperative rendezvous

    NASA Astrophysics Data System (ADS)

    Shang, Yang; Zhang, Yueqiang; Liu, Haibo

    2015-10-01

    In order to fully navigate using a vision sensor, a 3D edge model based detection and tracking technique was developed. Firstly, we proposed a target detection strategy over a sequence of several images from the 3D model to initialize the tracking. The overall purpose of such approach is to robustly match each image with the model views of the target. Thus we designed a line segment detection and matching method based on the multi-scale space technology. Experiments on real images showed that our method is highly robust under various image changes. Secondly, we proposed a method based on 3D particle filter (PF) coupled with M-estimation to track and estimate the pose of the target efficiently. In the proposed approach, a similarity observation model was designed according to a new distance function of line segments. Then, based on the tracking results of PF, the pose was optimized using M-estimation. Experiments indicated that the proposed method can effectively track and accurately estimate the pose of freely moving target in unconstrained environment.

  18. 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

  19. Extracting, Tracking, and Visualizing Magnetic Flux Vortices in 3D Complex-Valued Superconductor Simulation Data.

    PubMed

    Guo, Hanqi; Phillips, Carolyn L; Peterka, Tom; Karpeyev, Dmitry; Glatz, Andreas

    2016-01-01

    We propose a method for the vortex extraction and tracking of superconducting magnetic flux vortices for both structured and unstructured mesh data. In the Ginzburg-Landau theory, magnetic flux vortices are well-defined features in a complex-valued order parameter field, and their dynamics determine electromagnetic properties in type-II superconductors. Our method represents each vortex line (a 1D curve embedded in 3D space) as a connected graph extracted from the discretized field in both space and time. For a time-varying discrete dataset, our vortex extraction and tracking method is as accurate as the data discretization. We then apply 3D visualization and 2D event diagrams to the extraction and tracking results to help scientists understand vortex dynamics and macroscale superconductor behavior in greater detail than previously possible. PMID:26529730

  20. Label free cell tracking in 3D tissue engineering constructs with high resolution imaging

    NASA Astrophysics Data System (ADS)

    Smith, W. A.; Lam, K.-P.; Dempsey, K. P.; Mazzocchi-Jones, D.; Richardson, J. B.; Yang, Y.

    2014-02-01

    Within the field of tissue engineering there is an emphasis on studying 3-D live tissue structures. Consequently, to investigate and identify cellular activities and phenotypes in a 3-D environment for all in vitro experiments, including shape, migration/proliferation and axon projection, it is necessary to adopt an optical imaging system that enables monitoring 3-D cellular activities and morphology through the thickness of the construct for an extended culture period without cell labeling. This paper describes a new 3-D tracking algorithm developed for Cell-IQ®, an automated cell imaging platform, which has been equipped with an environmental chamber optimized to enable capturing time-lapse sequences of live cell images over a long-term period without cell labeling. As an integral part of the algorithm, a novel auto-focusing procedure was developed for phase contrast microscopy equipped with 20x and 40x objectives, to provide a more accurate estimation of cell growth/trajectories by allowing 3-D voxels to be computed at high spatiotemporal resolution and cell density. A pilot study was carried out in a phantom system consisting of horizontally aligned nanofiber layers (with precise spacing between them), to mimic features well exemplified in cellular activities of neuronal growth in a 3-D environment. This was followed by detailed investigations concerning axonal projections and dendritic circuitry formation in a 3-D tissue engineering construct. Preliminary work on primary animal neuronal cells in response to chemoattractant and topographic cue within the scaffolds has produced encouraging results.

  1. Eye Tracking to Explore the Impacts of Photorealistic 3d Representations in Pedstrian Navigation Performance

    NASA Astrophysics Data System (ADS)

    Dong, Weihua; Liao, Hua

    2016-06-01

    Despite the now-ubiquitous two-dimensional (2D) maps, photorealistic three-dimensional (3D) representations of cities (e.g., Google Earth) have gained much attention by scientists and public users as another option. However, there is no consistent evidence on the influences of 3D photorealism on pedestrian navigation. Whether 3D photorealism can communicate cartographic information for navigation with higher effectiveness and efficiency and lower cognitive workload compared to the traditional symbolic 2D maps remains unknown. This study aims to explore whether the photorealistic 3D representation can facilitate processes of map reading and navigation in digital environments using a lab-based eye tracking approach. Here we show the differences of symbolic 2D maps versus photorealistic 3D representations depending on users' eye-movement and navigation behaviour data. We found that the participants using the 3D representation were less effective, less efficient and were required higher cognitive workload than using the 2D map for map reading. However, participants using the 3D representation performed more efficiently in self-localization and orientation at the complex decision points. The empirical results can be helpful to improve the usability of pedestrian navigation maps in future designs.

  2. Towards robust 3D visual tracking for motion compensation in beating heart surgery.

    PubMed

    Richa, Rogério; Bó, Antônio P L; Poignet, Philippe

    2011-06-01

    In the context of minimally invasive cardiac surgery, active vision-based motion compensation schemes have been proposed for mitigating problems related to physiological motion. However, robust and accurate visual tracking remains a difficult task. The purpose of this paper is to present a robust visual tracking method that estimates the 3D temporal and spatial deformation of the heart surface using stereo endoscopic images. The novelty is the combination of a visual tracking method based on a Thin-Plate Spline (TPS) model for representing the heart surface deformations with a temporal heart motion model based on a time-varying dual Fourier series for overcoming tracking disturbances or failures. The considerable improvements in tracking robustness facing specular reflections and occlusions are demonstrated through experiments using images of in vivo porcine and human beating hearts. PMID:21277821

  3. Alignment of 3D Building Models and TIR Video Sequences with Line Tracking

    NASA Astrophysics Data System (ADS)

    Iwaszczuk, D.; Stilla, U.

    2014-11-01

    Thermal infrared imagery of urban areas became interesting for urban climate investigations and thermal building inspections. Using a flying platform such as UAV or a helicopter for the acquisition and combining the thermal data with the 3D building models via texturing delivers a valuable groundwork for large-area building inspections. However, such thermal textures are useful for further analysis if they are geometrically correctly extracted. This can be achieved with a good coregistrations between the 3D building models and thermal images, which cannot be achieved by direct georeferencing. Hence, this paper presents methodology for alignment of 3D building models and oblique TIR image sequences taken from a flying platform. In a single image line correspondences between model edges and image line segments are found using accumulator approach and based on these correspondences an optimal camera pose is calculated to ensure the best match between the projected model and the image structures. Among the sequence the linear features are tracked based on visibility prediction. The results of the proposed methodology are presented using a TIR image sequence taken from helicopter in a densely built-up urban area. The novelty of this work is given by employing the uncertainty of the 3D building models and by innovative tracking strategy based on a priori knowledge from the 3D building model and the visibility checking.

  4. 3D single-molecule tracking using one- and two-photon excitation microscopy

    NASA Astrophysics Data System (ADS)

    Liu, Cong; Perillo, Evan P.; Zhuang, Quincy; Huynh, Khang T.; Dunn, Andrew K.; Yeh, Hsin-Chih

    2014-03-01

    Three dimensional single-molecule tracking (3D-SMT) has revolutionized the way we study fundamental cellular processes. By analyzing the spatial trajectories of individual molecules (e.g. a receptor or a signaling molecule) in 3D space, one can discern the internalization or transport dynamics of these molecules, study the heterogeneity of subcellular structures, and elucidate the complex spatiotemporal regulation mechanisms. Sub-diffraction localization precision, sub-millisecond temporal resolution and tens-of-seconds observation period are the benchmarks of current 3D-SMT techniques. We have recently built two molecular tracking systems in our labs. The first system is a previously reported confocal tracking system, which we denote as the 1P-1E-4D (one-photon excitation, one excitation beam, and four fiber-coupled detectors) system. The second system is a whole new design that is based on two-photon excitation, which we denote as the 2P-4E-1D (two-photon excitation, four excitation beams, and only one detector) system. Here we compare these two systems based on Monte Carlo simulation of tracking a diffusing fluorescent molecule. Through our simulation, we have characterized the limitation of individual systems and optimized the system parameters such as magnification, z-plane separation, and feedback gains.

  5. Drogue tracking using 3D flash lidar for autonomous aerial refueling

    NASA Astrophysics Data System (ADS)

    Chen, Chao-I.; Stettner, Roger

    2011-06-01

    Autonomous aerial refueling (AAR) is an important capability for an unmanned aerial vehicle (UAV) to increase its flying range and endurance without increasing its size. This paper presents a novel tracking method that utilizes both 2D intensity and 3D point-cloud data acquired with a 3D Flash LIDAR sensor to establish relative position and orientation between the receiver vehicle and drogue during an aerial refueling process. Unlike classic, vision-based sensors, a 3D Flash LIDAR sensor can provide 3D point-cloud data in real time without motion blur, in the day or night, and is capable of imaging through fog and clouds. The proposed method segments out the drogue through 2D analysis and estimates the center of the drogue from 3D point-cloud data for flight trajectory determination. A level-set front propagation routine is first employed to identify the target of interest and establish its silhouette information. Sufficient domain knowledge, such as the size of the drogue and the expected operable distance, is integrated into our approach to quickly eliminate unlikely target candidates. A statistical analysis along with a random sample consensus (RANSAC) is performed on the target to reduce noise and estimate the center of the drogue after all 3D points on the drogue are identified. The estimated center and drogue silhouette serve as the seed points to efficiently locate the target in the next frame.

  6. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking.

    PubMed

    Dettmer, Simon L; Keyser, Ulrich F; Pagliara, Stefano

    2014-02-01

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces. PMID:24593372

  7. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking

    NASA Astrophysics Data System (ADS)

    Dettmer, Simon L.; Keyser, Ulrich F.; Pagliara, Stefano

    2014-02-01

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces.

  8. Fast parallel interferometric 3D tracking of numerous optically trapped particles and their hydrodynamic interaction.

    PubMed

    Ruh, Dominic; Tränkle, Benjamin; Rohrbach, Alexander

    2011-10-24

    Multi-dimensional, correlated particle tracking is a key technology to reveal dynamic processes in living and synthetic soft matter systems. In this paper we present a new method for tracking micron-sized beads in parallel and in all three dimensions - faster and more precise than existing techniques. Using an acousto-optic deflector and two quadrant-photo-diodes, we can track numerous optically trapped beads at up to tens of kHz with a precision of a few nanometers by back-focal plane interferometry. By time-multiplexing the laser focus, we can calibrate individually all traps and all tracking signals in a few seconds and in 3D. We show 3D histograms and calibration constants for nine beads in a quadratic arrangement, although trapping and tracking is easily possible for more beads also in arbitrary 2D arrangements. As an application, we investigate the hydrodynamic coupling and diffusion anomalies of spheres trapped in a 3 × 3 arrangement. PMID:22109012

  9. Measurement Matrix Optimization and Mismatch Problem Compensation for DLSLA 3-D SAR Cross-Track Reconstruction.

    PubMed

    Bao, Qian; Jiang, Chenglong; Lin, Yun; Tan, Weixian; Wang, Zhirui; Hong, Wen

    2016-01-01

    With a short linear array configured in the cross-track direction, downward looking sparse linear array three-dimensional synthetic aperture radar (DLSLA 3-D SAR) can obtain the 3-D image of an imaging scene. To improve the cross-track resolution, sparse recovery methods have been investigated in recent years. In the compressive sensing (CS) framework, the reconstruction performance depends on the property of measurement matrix. This paper concerns the technique to optimize the measurement matrix and deal with the mismatch problem of measurement matrix caused by the off-grid scatterers. In the model of cross-track reconstruction, the measurement matrix is mainly affected by the configuration of antenna phase centers (APC), thus, two mutual coherence based criteria are proposed to optimize the configuration of APCs. On the other hand, to compensate the mismatch problem of the measurement matrix, the sparse Bayesian inference based method is introduced into the cross-track reconstruction by jointly estimate the scatterers and the off-grid error. Experiments demonstrate the performance of the proposed APCs' configuration schemes and the proposed cross-track reconstruction method. PMID:27556471

  10. Local characterization of hindered Brownian motion by using digital video microscopy and 3D particle tracking

    SciTech Connect

    Dettmer, Simon L.; Keyser, Ulrich F.; Pagliara, Stefano

    2014-02-15

    In this article we present methods for measuring hindered Brownian motion in the confinement of complex 3D geometries using digital video microscopy. Here we discuss essential features of automated 3D particle tracking as well as diffusion data analysis. By introducing local mean squared displacement-vs-time curves, we are able to simultaneously measure the spatial dependence of diffusion coefficients, tracking accuracies and drift velocities. Such local measurements allow a more detailed and appropriate description of strongly heterogeneous systems as opposed to global measurements. Finite size effects of the tracking region on measuring mean squared displacements are also discussed. The use of these methods was crucial for the measurement of the diffusive behavior of spherical polystyrene particles (505 nm diameter) in a microfluidic chip. The particles explored an array of parallel channels with different cross sections as well as the bulk reservoirs. For this experiment we present the measurement of local tracking accuracies in all three axial directions as well as the diffusivity parallel to the channel axis while we observed no significant flow but purely Brownian motion. Finally, the presented algorithm is suitable also for tracking of fluorescently labeled particles and particles driven by an external force, e.g., electrokinetic or dielectrophoretic forces.

  11. Vision-based endoscope tracking for 3D ultrasound image-guided surgical navigation.

    PubMed

    Yang, L; Wang, J; Ando, T; Kubota, A; Yamashita, H; Sakuma, I; Chiba, T; Kobayashi, E

    2015-03-01

    This work introduces a self-contained framework for endoscopic camera tracking by combining 3D ultrasonography with endoscopy. The approach can be readily incorporated into surgical workflows without installing external tracking devices. By fusing the ultrasound-constructed scene geometry with endoscopic vision, this integrated approach addresses issues related to initialization, scale ambiguity, and interest point inadequacy that may be faced by conventional vision-based approaches when applied to fetoscopic procedures. Vision-based pose estimations were demonstrated by phantom and ex vivo monkey placenta imaging. The potential contribution of this method may extend beyond fetoscopic procedures to include general augmented reality applications in minimally invasive procedures. PMID:25263644

  12. A 3D front tracking method on a CPU/GPU system

    SciTech Connect

    Bo, Wurigen; Grove, John

    2011-01-21

    We describe the method to port a sequential 3D interface tracking code to a GPU with CUDA. The interface is represented as a triangular mesh. Interface geometry properties and point propagation are performed on a GPU. Interface mesh adaptation is performed on a CPU. The convergence of the method is assessed from the test problems with given velocity fields. Performance results show overall speedups from 11 to 14 for the test problems under mesh refinement. We also briefly describe our ongoing work to couple the interface tracking method with a hydro solver.

  13. Error control in the set-up of stereo camera systems for 3d animal tracking

    NASA Astrophysics Data System (ADS)

    Cavagna, A.; Creato, C.; Del Castello, L.; Giardina, I.; Melillo, S.; Parisi, L.; Viale, M.

    2015-12-01

    Three-dimensional tracking of animal systems is the key to the comprehension of collective behavior. Experimental data collected via a stereo camera system allow the reconstruction of the 3d trajectories of each individual in the group. Trajectories can then be used to compute some quantities of interest to better understand collective motion, such as velocities, distances between individuals and correlation functions. The reliability of the retrieved trajectories is strictly related to the accuracy of the 3d reconstruction. In this paper, we perform a careful analysis of the most significant errors affecting 3d reconstruction, showing how the accuracy depends on the camera system set-up and on the precision of the calibration parameters.

  14. 3D silicon sensors with variable electrode depth for radiation hard high resolution particle tracking

    NASA Astrophysics Data System (ADS)

    Da Vià, C.; Borri, M.; Dalla Betta, G.; Haughton, I.; Hasi, J.; Kenney, C.; Povoli, M.; Mendicino, R.

    2015-04-01

    3D sensors, with electrodes micro-processed inside the silicon bulk using Micro-Electro-Mechanical System (MEMS) technology, were industrialized in 2012 and were installed in the first detector upgrade at the LHC, the ATLAS IBL in 2014. They are the radiation hardest sensors ever made. A new idea is now being explored to enhance the three-dimensional nature of 3D sensors by processing collecting electrodes at different depths inside the silicon bulk. This technique uses the electric field strength to suppress the charge collection effectiveness of the regions outside the p-n electrodes' overlap. Evidence of this property is supported by test beam data of irradiated and non-irradiated devices bump-bonded with pixel readout electronics and simulations. Applications include High-Luminosity Tracking in the high multiplicity LHC forward regions. This paper will describe the technical advantages of this idea and the tracking application rationale.

  15. 3D Visualization of Monte-Carlo Simulation's of HZE Track Structure and Initial Chemical Species

    NASA Technical Reports Server (NTRS)

    Plante, Ianik; Cucinotta, Francis A.

    2009-01-01

    Heavy ions biophysics is important for space radiation risk assessment [1] and hadron-therapy [2]. The characteristic of heavy ions tracks include a very high energy deposition region close to the track (<20 nm) denoted as the track core, and an outer penumbra region consisting of individual secondary electrons (6-rays). A still open question is the radiobiological effects of 6- rays relative to the track core. Of importance is the induction of double-strand breaks (DSB) [3] and oxidative damage to the biomolecules and the tissue matrix, considered the most important lesions for acute and long term effects of radiation. In this work, we have simulated a 56Fe26+ ion track of 1 GeV/amu with our Monte-Carlo code RITRACKS [4]. The simulation results have been used to calculate the energy depiction and initial chemical species in a "voxelized" space, which is then visualized in 3D. Several voxels with dose >1000 Gy are found in the penumbra, some located 0.1 mm from the track core. In computational models, the DSB induction probability is calculated with radial dose [6], which may not take into account the higher RBE of electron track ends for DSB induction. Therefore, these simulations should help improve models of DSB induction and our understanding of heavy ions biophysics.

  16. Forward Modeling Method of Gravity and Magnetic Fields and Their Gradient Tensors Based on 3-D Delaunay Discretization in Cartesian and Spherical Coordinate Systems

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Chen, C.; Du, J.; Sun, S.; Liang, Q.

    2015-12-01

    In the study of the inversion of gravity and magnetic data, the discretization of underground space is usually achieved by the use of structured grids. For instance, using the regular block as the module unit to divide model space in Cartesian coordinate system and the tesseroid in spherical coordinate system. Structured grids show clear spatial structures and mathematical properties. However, the block can only provide a rough approximation to the given terrain and using the tesseroid to approximate the terrain even seems impracticable. These shape determining errors cause the reduction of forward modeling precision. Moreover, the precision decreases again while using the tesseroid as no analytical algorithm has been acquired. On the other hand, since most terrain data has a limited resolution, unstructured grids, based on the polyhedron or tetrahedron, could fill the space completely, which allows us to reduce errors in shape determination to the minima. In addition, the analytical algorithms for polyhedron have been proposed. In our study, we use the tetrahedron as the module unit to divide the underground space. Moreover, based on the former researches, we supplement new analytical algorithms for tetrahedron to forward modeling gravity and magnetic fields and their gradient tensors in both Cartesian and spherical coordinate systems. The algorithm is testified by comparing the forward gravity and magnetic data of a block with the data obtained using the existed algorithms. The absolute difference between these two data is under 10e-9 mGal. Our approach is suitable for the inversion of gravity and magnetic data in both Cartesian and spherical coordinate systems.This study is supported by Natural Science Fund of Hubei Province (Grant No.: 2015CFB361) and International Cooperation Project in Science and Technology of China (Grant No.: 2010DFA24580).

  17. 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.

  18. 3D motion tracking of the heart using Harmonic Phase (HARP) isosurfaces

    NASA Astrophysics Data System (ADS)

    Soliman, Abraam S.; Osman, Nael F.

    2010-03-01

    Tags are non-invasive features induced in the heart muscle that enable the tracking of heart motion. Each tag line, in fact, corresponds to a 3D tag surface that deforms with the heart muscle during the cardiac cycle. Tracking of tag surfaces deformation is useful for the analysis of left ventricular motion. Cardiac material markers (Kerwin et al, MIA, 1997) can be obtained from the intersections of orthogonal surfaces which can be reconstructed from short- and long-axis tagged images. The proposed method uses Harmonic Phase (HARP) method for tracking tag lines corresponding to a specific harmonic phase value and then the reconstruction of grid tag surfaces is achieved by a Delaunay triangulation-based interpolation for sparse tag points. Having three different tag orientations from short- and long-axis images, the proposed method showed the deformation of 3D tag surfaces during the cardiac cycle. Previous work on tag surface reconstruction was restricted for the "dark" tag lines; however, the use of HARP as proposed enables the reconstruction of isosurfaces based on their harmonic phase values. The use of HARP, also, provides a fast and accurate way for tag lines identification and tracking, and hence, generating the surfaces.

  19. High-throughput lensfree 3D tracking of human sperms reveals rare statistics of helical trajectories

    PubMed Central

    Su, Ting-Wei; Xue, Liang; Ozcan, Aydogan

    2012-01-01

    Dynamic tracking of human sperms across a large volume is a challenging task. To provide a high-throughput solution to this important need, here we describe a lensfree on-chip imaging technique that can track the three-dimensional (3D) trajectories of > 1,500 individual human sperms within an observation volume of approximately 8–17 mm3. This computational imaging platform relies on holographic lensfree shadows of sperms that are simultaneously acquired at two different wavelengths, emanating from two partially-coherent sources that are placed at 45° with respect to each other. This multiangle and multicolor illumination scheme permits us to dynamically track the 3D motion of human sperms across a field-of-view of > 17 mm2 and depth-of-field of approximately 0.5–1 mm with submicron positioning accuracy. The large statistics provided by this lensfree imaging platform revealed that only approximately 4–5% of the motile human sperms swim along well-defined helices and that this percentage can be significantly suppressed under seminal plasma. Furthermore, among these observed helical human sperms, a significant majority (approximately 90%) preferred right-handed helices over left-handed ones, with a helix radius of approximately 0.5–3 μm, a helical rotation speed of approximately 3–20 rotations/s and a linear speed of approximately 20–100 μm/s. This high-throughput 3D imaging platform could in general be quite valuable for observing the statistical swimming patterns of various other microorganisms, leading to new insights in their 3D motion and the underlying biophysics. PMID:22988076

  20. Meanie3D - a mean-shift based, multivariate, multi-scale clustering and tracking algorithm

    NASA Astrophysics Data System (ADS)

    Simon, Jürgen-Lorenz; Malte, Diederich; Silke, Troemel

    2014-05-01

    Project OASE is the one of 5 work groups at the HErZ (Hans Ertel Centre for Weather Research), an ongoing effort by the German weather service (DWD) to further research at Universities concerning weather prediction. The goal of project OASE is to gain an object-based perspective on convective events by identifying them early in the onset of convective initiation and follow then through the entire lifecycle. The ability to follow objects in this fashion requires new ways of object definition and tracking, which incorporate all the available data sets of interest, such as Satellite imagery, weather Radar or lightning counts. The Meanie3D algorithm provides the necessary tool for this purpose. Core features of this new approach to clustering (object identification) and tracking are the ability to identify objects using the mean-shift algorithm applied to a multitude of variables (multivariate), as well as the ability to detect objects on various scales (multi-scale) using elements of Scale-Space theory. The algorithm works in 2D as well as 3D without modifications. It is an extension of a method well known from the field of computer vision and image processing, which has been tailored to serve the needs of the meteorological community. In spite of the special application to be demonstrated here (like convective initiation), the algorithm is easily tailored to provide clustering and tracking for a wide class of data sets and problems. In this talk, the demonstration is carried out on two of the OASE group's own composite sets. One is a 2D nationwide composite of Germany including C-Band Radar (2D) and Satellite information, the other a 3D local composite of the Bonn/Jülich area containing a high-resolution 3D X-Band Radar composite.

  1. Automated 3-D tracking of centrosomes in sequences of confocal image stacks.

    PubMed

    Kerekes, Ryan A; Gleason, Shaun S; Trivedi, Niraj; Solecki, David J

    2009-01-01

    In order to facilitate the study of neuron migration, we propose a method for 3-D detection and tracking of centrosomes in time-lapse confocal image stacks of live neuron cells. We combine Laplacian-based blob detection, adaptive thresholding, and the extraction of scale and roundness features to find centrosome-like objects in each frame. We link these detections using the joint probabilistic data association filter (JPDAF) tracking algorithm with a Newtonian state-space model tailored to the motion characteristics of centrosomes in live neurons. We apply our algorithm to image sequences containing multiple cells, some of which had been treated with motion-inhibiting drugs. We provide qualitative results and quantitative comparisons to manual segmentation and tracking results showing that our average motion estimates agree to within 13% of those computed manually by neurobiologists. PMID:19964725

  2. Sensor Spatial Distortion, Visual Latency, and Update Rate Effects on 3D Tracking in Virtual Environments

    NASA Technical Reports Server (NTRS)

    Ellis, S. R.; Adelstein, B. D.; Baumeler, S.; Jense, G. J.; Jacoby, R. H.; Trejo, Leonard (Technical Monitor)

    1998-01-01

    Several common defects that we have sought to minimize in immersing virtual environments are: static sensor spatial distortion, visual latency, and low update rates. Human performance within our environments during large amplitude 3D tracking was assessed by objective and subjective methods in the presence and absence of these defects. Results show that 1) removal of our relatively small spatial sensor distortion had minor effects on the tracking activity, 2) an Adapted Cooper-Harper controllability scale proved the most sensitive subjective indicator of the degradation of dynamic fidelity caused by increasing latency and decreasing frame rates, and 3) performance, as measured by normalized RMS tracking error or subjective impressions, was more markedly influenced by changing visual latency than by update rate.

  3. A brain-computer interface method combined with eye tracking for 3D interaction.

    PubMed

    Lee, Eui Chul; Woo, Jin Cheol; Kim, Jong Hwa; Whang, Mincheol; Park, Kang Ryoung

    2010-07-15

    With the recent increase in the number of three-dimensional (3D) applications, the need for interfaces to these applications has increased. Although the eye tracking method has been widely used as an interaction interface for hand-disabled persons, this approach cannot be used for depth directional navigation. To solve this problem, we propose a new brain computer interface (BCI) method in which the BCI and eye tracking are combined to analyze depth navigation, including selection and two-dimensional (2D) gaze direction, respectively. The proposed method is novel in the following five ways compared to previous works. First, a device to measure both the gaze direction and an electroencephalogram (EEG) pattern is proposed with the sensors needed to measure the EEG attached to a head-mounted eye tracking device. Second, the reliability of the BCI interface is verified by demonstrating that there is no difference between the real and the imaginary movements for the same work in terms of the EEG power spectrum. Third, depth control for the 3D interaction interface is implemented by an imaginary arm reaching movement. Fourth, a selection method is implemented by an imaginary hand grabbing movement. Finally, for the independent operation of gazing and the BCI, a mode selection method is proposed that measures a user's concentration by analyzing the pupil accommodation speed, which is not affected by the operation of gazing and the BCI. According to experimental results, we confirmed the feasibility of the proposed 3D interaction method using eye tracking and a BCI. PMID:20580646

  4. Using natural versus artificial stimuli to perform calibration for 3D gaze tracking

    NASA Astrophysics Data System (ADS)

    Maggia, Christophe; Guyader, Nathalie; Guérin-Dugué, Anne

    2013-03-01

    The presented study tests which type of stereoscopic image, natural or artificial, is more adapted to perform efficient and reliable calibration in order to track the gaze of observers in 3D space using classical 2D eye tracker. We measured the horizontal disparities, i.e. the difference between the x coordinates of the two eyes obtained using a 2D eye tracker. This disparity was recorded for each observer and for several target positions he had to fixate. Target positions were equally distributed in the 3D space, some on the screen (with a null disparity), some behind the screen (uncrossed disparity) and others in front of the screen (crossed disparity). We tested different regression models (linear and non linear) to explain either the true disparity or the depth with the measured disparity. Models were tested and compared on their prediction error for new targets at new positions. First of all, we found that we obtained more reliable disparities measures when using natural stereoscopic images rather than artificial. Second, we found that overall a non-linear model was more efficient. Finally, we discuss the fact that our results were observer dependent, with variability's between the observer's behavior when looking at 3D stimuli. Because of this variability, we proposed to compute observer specific model to accurately predict their gaze position when exploring 3D stimuli.

  5. Microfabricated collagen tracks facilitate single cell metastatic invasion in 3D.

    PubMed

    Kraning-Rush, Casey M; Carey, Shawn P; Lampi, Marsha C; Reinhart-King, Cynthia A

    2013-03-01

    While the mechanisms employed by metastatic cancer cells to migrate remain poorly understood, it has been widely accepted that metastatic cancer cells can invade the tumor stroma by degrading the extracellular matrix (ECM) with matrix metalloproteinases (MMPs). Although MMP inhibitors showed early promise in preventing metastasis in animal models, they have largely failed clinically. Recently, studies have shown that some cancer cells can use proteolysis to mechanically rearrange their ECM to form tube-like "microtracks" which other cells can follow without using MMPs themselves. We speculate that this mode of migration in the secondary cells may be one example of migration which can occur without endogenous protease activity in the secondary cells. Here we present a technique to study this migration in a 3D, collagen-based environment which mimics the size and topography of the tracks produced by proteolytically active cancer cells. Using time-lapse phase-contrast microscopy, we find that these microtracks permit the rapid and persistent migration of noninvasive MCF10A mammary epithelial cells, which are unable to otherwise migrate in 3D collagen. Additionally, while highly metastatic MDAMB231 breast cancer cells are able to invade a 3D collagen matrix, seeding within the patterned microtracks induced significantly increased cell migration speed, which was not decreased by pharmacological MMP inhibition. Together, these data suggest that microtracks within a 3D ECM may facilitate the migration of cells in an MMP-independent fashion, and may reveal novel insight into the clinical challenges facing MMP inhibitors. PMID:23388698

  6. Detection, 3-D positioning, and sizing of small pore defects using digital radiography and tracking

    NASA Astrophysics Data System (ADS)

    Lindgren, Erik

    2014-12-01

    This article presents an algorithm that handles the detection, positioning, and sizing of submillimeter-sized pores in welds using radiographic inspection and tracking. The possibility to detect, position, and size pores which have a low contrast-to-noise ratio increases the value of the nondestructive evaluation of welds by facilitating fatigue life predictions with lower uncertainty. In this article, a multiple hypothesis tracker with an extended Kalman filter is used to track an unknown number of pore indications in a sequence of radiographs as an object is rotated. Each pore is not required to be detected in all radiographs. In addition, in the tracking step, three-dimensional (3-D) positions of pore defects are calculated. To optimize, set up, and pre-evaluate the algorithm, the article explores a design of experimental approach in combination with synthetic radiographs of titanium laser welds containing pore defects. The pre-evaluation on synthetic radiographs at industrially reasonable contrast-to-noise ratios indicate less than 1% false detection rates at high detection rates and less than 0.1 mm of positioning errors for more than 90% of the pores. A comparison between experimental results of the presented algorithm and a computerized tomography reference measurement shows qualitatively good agreement in the 3-D positions of approximately 0.1-mm diameter pores in 5-mm-thick Ti-6242.

  7. METHODS FOR USING 3-D ULTRASOUND SPECKLE TRACKING IN BIAXIAL MECHANICAL TESTING OF BIOLOGICAL TISSUE SAMPLES

    PubMed Central

    Yap, Choon Hwai; Park, Dae Woo; Dutta, Debaditya; Simon, Marc; Kim, Kang

    2014-01-01

    Being multilayered and anisotropic, biological tissues such as cardiac and arterial walls are structurally complex, making full assessment and understanding of their mechanical behavior challenging. Current standard mechanical testing uses surface markers to track tissue deformations and does not provide deformation data below the surface. In the study described here, we found that combining mechanical testing with 3-D ultrasound speckle tracking could overcome this limitation. Rat myocardium was tested with a biaxial tester and was concurrently scanned with high-frequency ultrasound in three dimensions. The strain energy function was computed from stresses and strains using an iterative non-linear curve-fitting algorithm. Because the strain energy function consists of terms for the base matrix and for embedded fibers, spatially varying fiber orientation was also computed by curve fitting. Using finite-element simulations, we first validated the accuracy of the non-linear curve-fitting algorithm. Next, we compared experimentally measured rat myocardium strain energy function values with those in the literature and found a matching order of magnitude. Finally, we retained samples after the experiments for fiber orientation quantification using histology and found that the results satisfactorily matched those computed in the experiments. We conclude that 3-D ultrasound speckle tracking can be a useful addition to traditional mechanical testing of biological tissues and may provide the benefit of enabling fiber orientation computation. PMID:25616585

  8. Ultrasonic diaphragm tracking for cardiac interventional navigation on 3D motion compensated static roadmaps

    NASA Astrophysics Data System (ADS)

    Timinger, Holger; Kruger, Sascha; Dietmayer, Klaus; Borgert, Joern

    2005-04-01

    In this paper, a novel approach to cardiac interventional navigation on 3D motion-compensated static roadmaps is presented. Current coronary interventions, e.g. percutaneous transluminal coronary angioplasties, are performed using 2D X-ray fluoroscopy. This comes along with well-known drawbacks like radiation exposure, use of contrast agent, and limited visualization, e.g. overlap and foreshortening, due to projection imaging. In the presented approach, the interventional device, i.e. the catheter, is tracked using an electromagnetic tracking system (MTS). Therefore, the catheters position is mapped into a static 3D image of the volume of interest (VOI) by means of an affine registration. In order to compensate for respiratory motion of the catheter with respect to the static image, a parameterized affine motion model is used which is driven by a respiratory sensor signal. This signal is derived from ultrasonic diaphragm tracking. The motion compensation for the heartbeat is done using ECG-gating. The methods are validated using a heart- and diaphragm-phantom. The mean displacement of the catheter due to the simulated organ motion decreases from approximately 9 mm to 1.3 mm. This result indicates that the proposed method is able to reconstruct the catheter position within the VOI accurately and that it can help to overcome drawbacks of current interventional procedures.

  9. 3D measurement of the position of gold particles via evanescent digital holographic particle tracking velocimetry

    NASA Astrophysics Data System (ADS)

    Satake, Shin-ichi; Unno, Noriyuki; Nakata, Shuichiro; Taniguchi, Jun

    2016-08-01

    A new technique based on digital holography and evanescent waves was developed for 3D measurements of the position of gold nanoparticles in water. In this technique, an intensity profile is taken from a holographic image of a gold particle. To detect the position of the gold particle with high accuracy, its holographic image is recorded on a nanosized step made of MEXFLON, which has a refractive index close to that of water, and the position of the particle is reconstructed by means of digital holography. The height of the nanosized step was measured by using a profilometer and the digitally reconstructed height of the glass substrate had good agreement with the measured value. Furthermore, this method can be used to accurately track the 3D position of a gold particle in water.

  10. Oblique needle segmentation and tracking for 3D TRUS guided prostate brachytherapy

    SciTech Connect

    Wei Zhouping; Gardi, Lori; Downey, Donal B.; Fenster, Aaron

    2005-09-15

    An algorithm was developed in order to segment and track brachytherapy needles inserted along oblique trajectories. Three-dimensional (3D) transrectal ultrasound (TRUS) images of the rigid rod simulating the needle inserted into the tissue-mimicking agar and chicken breast phantoms were obtained to test the accuracy of the algorithm under ideal conditions. Because the robot possesses high positioning and angulation accuracies, we used the robot as a ''gold standard,'' and compared the results of algorithm segmentation to the values measured by the robot. Our testing results showed that the accuracy of the needle segmentation algorithm depends on the needle insertion distance into the 3D TRUS image and the angulations with respect to the TRUS transducer, e.g., at a 10 deg. insertion anglulation in agar phantoms, the error of the algorithm in determining the needle tip position was less than 1 mm when the insertion distance was greater than 15 mm. Near real-time needle tracking was achieved by scanning a small volume containing the needle. Our tests also showed that, the segmentation time was less than 60 ms, and the scanning time was less than 1.2 s, when the insertion distance into the 3D TRUS image was less than 55 mm. In our needle tracking tests in chicken breast phantoms, the errors in determining the needle orientation were less than 2 deg. in robot yaw and 0.7 deg. in robot pitch orientations, for up to 20 deg. needle insertion angles with the TRUS transducer in the horizontal plane when the needle insertion distance was greater than 15 mm.

  11. An automated tool for 3D tracking of single molecules in living cells

    NASA Astrophysics Data System (ADS)

    Gardini, L.; Capitanio, M.; Pavone, F. S.

    2015-03-01

    Since the behaviour of proteins and biological molecules is tightly related to cell's environment, more and more microscopy techniques are moving from in vitro to in living cells experiments. Looking at both diffusion and active transportation processes inside a cell requires three-dimensional localization over a few microns range, high SNR images and high temporal resolution. Since protein dynamics inside a cell involve all three dimensions, we developed an automated routine for 3D tracking of single fluorescent molecules inside living cells with nanometer accuracy, by exploiting the properties of the point-spread-function of out-of-focus Quantum Dots bound to the protein of interest.

  12. Study of a viewer tracking system with multiview 3D display

    NASA Astrophysics Data System (ADS)

    Yang, Jinn-Cherng; Wu, Chang-Shuo; Hsiao, Chuan-Heng; Yang, Ming-Chieh; Liu, Wen-Chieh; Hung, Yi-Ping

    2008-02-01

    An autostereoscopic display provides users great enjoyment of stereo visualization without uncomfortable and inconvenient drawbacks of wearing stereo glasses. However, bandwidth constraints of current multi-view 3D display severely restrict the number of views that can be simultaneously displayed without degrading resolution or increasing display cost unacceptably. An alternative to multiple view presentation is that the position of observer can be measured by using viewer-tracking sensor. It is a very important module of the viewer-tracking component for fluently rendering and accurately projecting the stereo video. In order to render stereo content with respect to user's view points and to optically project the content onto the left and right eyes of the user accurately, the real-time viewer tracking technique that allows the user to move around freely when watching the autostereoscopic display is developed in this study. It comprises the face detection by using multiple eigenspaces of various lighting conditions, fast block matching for tracking four motion parameters of the user's face region. The Edge Orientation Histogram (EOH) on Real AdaBoost to improve the performance of original AdaBoost algorithm is also applied in this study. The AdaBoost algorithm using Haar feature in OpenCV library developed by Intel to detect human face and enhance the accuracy performance with rotating image. The frame rate of viewer tracking process can achieve up to 15 Hz. Since performance of the viewer tracking autostereoscopic display is still influenced under variant environmental conditions, the accuracy, robustness and efficiency of the viewer-tracking system are evaluated in this study.

  13. The effect of object speed and direction on the performance of 3D speckle tracking using a 3D swept-volume ultrasound probe

    NASA Astrophysics Data System (ADS)

    Harris, Emma J.; Miller, Naomi R.; Bamber, Jeffrey C.; Symonds-Tayler, J. Richard N.; Evans, Philip M.

    2011-11-01

    Three-dimensional (3D) soft tissue tracking using 3D ultrasound is of interest for monitoring organ motion during therapy. Previously we demonstrated feature tracking of respiration-induced liver motion in vivo using a 3D swept-volume ultrasound probe. The aim of this study was to investigate how object speed affects the accuracy of tracking ultrasonic speckle in the absence of any structural information, which mimics the situation in homogenous tissue for motion in the azimuthal and elevational directions. For object motion prograde and retrograde to the sweep direction of the transducer, the spatial sampling frequency increases or decreases with object speed, respectively. We examined the effect object motion direction of the transducer on tracking accuracy. We imaged a homogenous ultrasound speckle phantom whilst moving the probe with linear motion at a speed of 0-35 mm s-1. Tracking accuracy and precision were investigated as a function of speed, depth and direction of motion for fixed displacements of 2 and 4 mm. For the azimuthal direction, accuracy was better than 0.1 and 0.15 mm for displacements of 2 and 4 mm, respectively. For a 2 mm displacement in the elevational direction, accuracy was better than 0.5 mm for most speeds. For 4 mm elevational displacement with retrograde motion, accuracy and precision reduced with speed and tracking failure was observed at speeds of greater than 14 mm s-1. Tracking failure was attributed to speckle de-correlation as a result of decreasing spatial sampling frequency with increasing speed of retrograde motion. For prograde motion, tracking failure was not observed. For inter-volume displacements greater than 2 mm, only prograde motion should be tracked which will decrease temporal resolution by a factor of 2. Tracking errors of the order of 0.5 mm for prograde motion in the elevational direction indicates that using the swept probe technology speckle tracking accuracy is currently too poor to track homogenous tissue over

  14. Longitudinal Measurement of Extracellular Matrix Rigidity in 3D Tumor Models Using Particle-tracking Microrheology

    PubMed Central

    El-Hamidi, Hamid; Celli, Jonathan P.

    2014-01-01

    The mechanical microenvironment has been shown to act as a crucial regulator of tumor growth behavior and signaling, which is itself remodeled and modified as part of a set of complex, two-way mechanosensitive interactions. While the development of biologically-relevant 3D tumor models have facilitated mechanistic studies on the impact of matrix rheology on tumor growth, the inverse problem of mapping changes in the mechanical environment induced by tumors remains challenging. Here, we describe the implementation of particle-tracking microrheology (PTM) in conjunction with 3D models of pancreatic cancer as part of a robust and viable approach for longitudinally monitoring physical changes in the tumor microenvironment, in situ. The methodology described here integrates a system of preparing in vitro 3D models embedded in a model extracellular matrix (ECM) scaffold of Type I collagen with fluorescently labeled probes uniformly distributed for position- and time-dependent microrheology measurements throughout the specimen. In vitro tumors are plated and probed in parallel conditions using multiwell imaging plates. Drawing on established methods, videos of tracer probe movements are transformed via the Generalized Stokes Einstein Relation (GSER) to report the complex frequency-dependent viscoelastic shear modulus, G*(ω). Because this approach is imaging-based, mechanical characterization is also mapped onto large transmitted-light spatial fields to simultaneously report qualitative changes in 3D tumor size and phenotype. Representative results showing contrasting mechanical response in sub-regions associated with localized invasion-induced matrix degradation as well as system calibration, validation data are presented. Undesirable outcomes from common experimental errors and troubleshooting of these issues are also presented. The 96-well 3D culture plating format implemented in this protocol is conducive to correlation of microrheology measurements with therapeutic

  15. Forward-looking infrared 3D target tracking via combination of particle filter and SIFT

    NASA Astrophysics Data System (ADS)

    Li, Xing; Cao, Zhiguo; Yan, Ruicheng; Li, Tuo

    2013-10-01

    Aiming at the problem of tracking 3D target in forward-looking infrared (FLIR) image, this paper proposes a high-accuracy robust tracking algorithm based on SIFT and particle filter. The main contribution of this paper is the proposal of a new method of estimating the affine transformation matrix parameters based on Monte Carlo methods of particle filter. At first, we extract SIFT features on infrared image, and calculate the initial affine transformation matrix with optimal candidate key points. Then we take affine transformation parameters as particles, and use SIR (Sequential Importance Resampling) particle filter to estimate the best position, thus implementing our algorithm. The experiments demonstrate that our algorithm proves to be robust with high accuracy.

  16. An automated tool for 3D tracking of single molecules in living cells

    NASA Astrophysics Data System (ADS)

    Gardini, L.; Capitanio, M.; Pavone, F. S.

    2015-07-01

    Recently, tremendous improvements have been achieved in the precision of localization of single fluorescent molecules, allowing localization and tracking of biomolecules at the nm level. Since the behaviour of proteins and biological molecules is tightly influenced by the cell's environment, a growing number of microscopy techniques are moving from in vitro to live cell experiments. Looking at both diffusion and active transportation processes inside a cell requires three-dimensional localization over a few microns range, high SNR images and high temporal resolution (ms order of magnitude). To satisfy these requirements we developed an automated routine that allow 3D tracking of single fluorescent molecules in living cells with nanometer accuracy, by exploiting the properties of the point-spread-function of out-of-focus Quantum Dots bound to the protein of interest.

  17. 3D Fluorescent and Reflective Imaging of Whole Stardust Tracks in Aerogel

    SciTech Connect

    Greenberg, M.; Ebel, D.S.

    2011-11-07

    The NASA Stardust mission returned to earth in 2006 with the cometary collector having captured over 1,000 particles in an aerogel medium at a relative velocity of 6.1 km/s. Particles captured in aerogel were heated, disaggregated and dispersed along 'tracks' or cavities in aerogel, singular tracks representing a history of one capture event. It has been our focus to chemically and morphologically characterize whole tracks in 3-dimensions, utilizing solely non-destructive methods. To this end, we have used a variety of methods: 3D Laser Scanning Confocal Microscopy (LSCM), synchrotron X-ray fluorescence (SXRF), and synchrotron X-ray diffraction (SXRD). In the past months we have developed two new techniques to aid in data collection. (1) We have received a new confocal microscope which has enabled autofluorescent and spectral imaging of aerogel samples. (2) We have developed a stereo-SXRF technique to chemically identify large grains in SXRF maps in 3-space. The addition of both of these methods to our analytic abilities provides a greater understanding of the mechanisms and results of track formation.

  18. Quantifying the 3D Odorant Concentration Field Used by Actively Tracking Blue Crabs

    NASA Astrophysics Data System (ADS)

    Webster, D. R.; Dickman, B. D.; Jackson, J. L.; Weissburg, M. J.

    2007-11-01

    Blue crabs and other aquatic organisms locate food and mates by tracking turbulent odorant plumes. The odorant concentration fluctuates unpredictably due to turbulent transport, and many characteristics of the fluctuation pattern have been hypothesized as useful cues for orienting to the odorant source. To make a direct linkage between tracking behavior and the odorant concentration signal, we developed a measurement system based the laser induced fluorescence technique to quantify the instantaneous 3D concentration field surrounding actively tracking blue crabs. The data suggest a correlation between upstream walking speed and the concentration of the odorant signal arriving at the antennule chemosensors, which are located near the mouth region. More specifically, we note an increase in upstream walking speed when high concentration bursts arrive at the antennules location. We also test hypotheses regarding the ability of blue crabs to steer relative to the plume centerline based on the signal contrast between the chemosensors located on their leg appendages. These chemosensors are located much closer to the substrate compared to the antennules and are separated by the width of the blue crab. In this case, it appears that blue crabs use the bilateral signal comparison to track along the edge of the plume.

  19. Mapping dynamic mechanical remodeling in 3D tumor models via particle tracking microrheology

    NASA Astrophysics Data System (ADS)

    Jones, Dustin P.; Hanna, William; Celli, Jonathan P.

    2015-03-01

    Particle tracking microrheology (PTM) has recently been employed as a non-destructive way to longitudinally track physical changes in 3D pancreatic tumor co-culture models concomitant with tumor growth and invasion into the extracellular matrix (ECM). While the primary goal of PTM is to quantify local viscoelasticity via the Generalized Stokes-Einstein Relation (GSER), a more simplified way of describing local tissue mechanics lies in the tabulation and subsequent visualization of the spread of probe displacements in a given field of view. Proper analysis of this largely untapped byproduct of standard PTM has the potential to yield valuable insight into the structure and integrity of the ECM. Here, we use clustering algorithms in R to analyze the trajectories of probes in 3D pancreatic tumor/fibroblast co-culture models in an attempt to differentiate between probes that are effectively constrained by the ECM and/or contractile traction forces, and those that exhibit uninhibited mobility in local water-filled pores. We also discuss the potential pitfalls of this method. Accurately and reproducibly quantifying the boundary between these two categories of probe behavior could result in an effective method for measuring the average pore size in a given region of ECM. Such a tool could prove useful for studying stromal depletion, physical impedance to drug delivery, and degradation due to cellular invasion.

  20. 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.

  1. Nondestructive 3D confocal laser imaging with deconvolution of seven whole stardust tracks with complementary XRF and quantitative analysis

    SciTech Connect

    Greenberg, M.; Ebel, D.S.

    2009-03-19

    We present a nondestructive 3D system for analysis of whole Stardust tracks, using a combination of Laser Confocal Scanning Microscopy and synchrotron XRF. 3D deconvolution is used for optical corrections, and results of quantitative analyses of several tracks are presented. The Stardust mission to comet Wild 2 trapped many cometary and ISM particles in aerogel, leaving behind 'tracks' of melted silica aerogel on both sides of the collector. Collected particles and their tracks range in size from submicron to millimeter scale. Interstellar dust collected on the obverse of the aerogel collector is thought to have an average track length of {approx}15 {micro}m. It has been our goal to perform a total non-destructive 3D textural and XRF chemical analysis on both types of tracks. To that end, we use a combination of Laser Confocal Scanning Microscopy (LCSM) and X Ray Florescence (XRF) spectrometry. Utilized properly, the combination of 3D optical data and chemical data provides total nondestructive characterization of full tracks, prior to flattening or other destructive analysis methods. Our LCSM techniques allow imaging at 0.075 {micro}m/pixel, without the use of oil-based lenses. A full textural analysis on track No.82 is presented here as well as analysis of 6 additional tracks contained within 3 keystones (No.128, No.129 and No.140). We present a method of removing the axial distortion inherent in LCSM images, by means of a computational 3D Deconvolution algorithm, and present some preliminary experiments with computed point spread functions. The combination of 3D LCSM data and XRF data provides invaluable information, while preserving the integrity of the samples for further analysis. It is imperative that these samples, the first extraterrestrial solids returned since the Apollo era, be fully mapped nondestructively in 3D, to preserve the maximum amount of information prior to other, destructive analysis.

  2. Segmentation and Tracking of Adherens Junctions in 3D for the Analysis of Epithelial Tissue Morphogenesis

    PubMed Central

    Cilla, Rodrigo; Mechery, Vinodh; Hernandez de Madrid, Beatriz; Del Signore, Steven; Dotu, Ivan; Hatini, Victor

    2015-01-01

    Epithelial morphogenesis generates the shape of tissues, organs and embryos and is fundamental for their proper function. It is a dynamic process that occurs at multiple spatial scales from macromolecular dynamics, to cell deformations, mitosis and apoptosis, to coordinated cell rearrangements that lead to global changes of tissue shape. Using time lapse imaging, it is possible to observe these events at a system level. However, to investigate morphogenetic events it is necessary to develop computational tools to extract quantitative information from the time lapse data. Toward this goal, we developed an image-based computational pipeline to preprocess, segment and track epithelial cells in 4D confocal microscopy data. The computational pipeline we developed, for the first time, detects the adherens junctions of epithelial cells in 3D, without the need to first detect cell nuclei. We accentuate and detect cell outlines in a series of steps, symbolically describe the cells and their connectivity, and employ this information to track the cells. We validated the performance of the pipeline for its ability to detect vertices and cell-cell contacts, track cells, and identify mitosis and apoptosis in surface epithelia of Drosophila imaginal discs. We demonstrate the utility of the pipeline to extract key quantitative features of cell behavior with which to elucidate the dynamics and biomechanical control of epithelial tissue morphogenesis. We have made our methods and data available as an open-source multiplatform software tool called TTT (http://github.com/morganrcu/TTT) PMID:25884654

  3. A 3D Vector/Scalar Visualization and Particle Tracking Package

    Energy Science and Technology Software Center (ESTSC)

    1999-08-19

    BOILERMAKER is an interactive visualization system consisting of three components: a visualization component, a particle tracking component, and a communication layer. The software, to date, has been used primarily in the visualization of vector and scalar fields associated with computational fluid dynamics (CFD) models of flue gas flows in industrial boilers and incinerators. Users can interactively request and toggle static vector fields, dynamic streamlines, and flowing vector fields. In addition, the user can interactively placemore » injector nozzles on boiler walls and visualize massed, evaporating sprays emanating from them. Some characteristics of the spray can be adjusted from within the visualization environment including spray shape and particle size. Also included with this release is software that supports 3D menu capabilities, scrollbars, communication and navigation.« less

  4. Neural network techniques for invariant recognition and motion tracking of 3-D objects

    SciTech Connect

    Hwang, J.N.; Tseng, Y.H.

    1995-12-31

    Invariant recognition and motion tracking of 3-D objects under partial object viewing are difficult tasks. In this paper, we introduce a new neural network solution that is robust to noise corruption and partial viewing of objects. This method directly utilizes the acquired range data and requires no feature extraction. In the proposed approach, the object is first parametrically represented by a continuous distance transformation neural network (CDTNN) which is trained by the surface points of the exemplar object. When later presented with the surface points of an unknown object, this parametric representation allows the mismatch information to back-propagate through the CDTNN to gradually determine the best similarity transformation (translation and rotation) of the unknown object. The mismatch can be directly measured in the reconstructed representation domain between the model and the unknown object.

  5. A 3D Vector/Scalar Visualization and Particle Tracking Package

    SciTech Connect

    Freitag, Lori; Disz, Terry; Papka, Mike; Heath, Daniel; Diachin, Darin; Herzog, Jim; Ryan, and Bob

    1999-08-19

    BOILERMAKER is an interactive visualization system consisting of three components: a visualization component, a particle tracking component, and a communication layer. The software, to date, has been used primarily in the visualization of vector and scalar fields associated with computational fluid dynamics (CFD) models of flue gas flows in industrial boilers and incinerators. Users can interactively request and toggle static vector fields, dynamic streamlines, and flowing vector fields. In addition, the user can interactively place injector nozzles on boiler walls and visualize massed, evaporating sprays emanating from them. Some characteristics of the spray can be adjusted from within the visualization environment including spray shape and particle size. Also included with this release is software that supports 3D menu capabilities, scrollbars, communication and navigation.

  6. Imaging SPR combined with stereoscopic 3D tracking to study barnacle cyprid-surface interactions

    NASA Astrophysics Data System (ADS)

    Maleshlijski, S.; Sendra, G. H.; Aldred, N.; Clare, A. S.; Liedberg, B.; Grunze, M.; Ederth, T.; Rosenhahn, A.

    2016-01-01

    Barnacle larvae (cyprids) explore surfaces to identify suitable settlement sites. This process is selective, and cyprids respond to numerous surface cues. To better understand the settlement process, it is desirable to simultaneously monitor both the surface exploration behavior and any close interactions with the surface. Stereoscopic 3D tracking of the cyprids provides quantitative access to surface exploration and pre-settlement rituals. Imaging surface plasmon resonance (SPR) reveals any interactions with the surfaces, such as surface inspection during bipedal walking and deposition of temporary adhesives. We report on a combination of both techniques to bring together information on swimming behavior in the vicinity of the interface and physical interactions of the cyprid with the surface. The technical requirements are described, and we applied the setup to cyprids of Balanus amphitrite. Initial data shows the applicability of the combined instrument to correlate exploration and touchdown events on surfaces with different chemical termination.

  7. CISUS: an integrated 3D ultrasound system for IGT using a modular tracking API

    NASA Astrophysics Data System (ADS)

    Boctor, Emad M.; Viswanathan, Anand; Pieper, Steve; Choti, Michael A.; Taylor, Russell H.; Kikinis, Ron; Fichtinger, Gabor

    2004-05-01

    Ultrasound has become popular in clinical/surgical applications, both as the primary image guidance modality and also in conjunction with other modalities like CT or MRI. Three dimensional ultrasound (3DUS) systems have also demonstrated usefulness in image-guided therapy (IGT). At the same time, however, current lack of open-source and open-architecture multi-modal medical visualization systems prevents 3DUS from fulfilling its potential. Several stand-alone 3DUS systems, like Stradx or In-Vivo exist today. Although these systems have been found to be useful in real clinical setting, it is difficult to augment their functionality and integrate them in versatile IGT systems. To address these limitations, a robotic/freehand 3DUS open environment (CISUS) is being integrated into the 3D Slicer, an open-source research tool developed for medical image analysis and surgical planning. In addition, the system capitalizes on generic application programming interfaces (APIs) for tracking devices and robotic control. The resulting platform-independent open-source system may serve as a valuable tool to the image guided surgery community. Other researchers could straightforwardly integrate the generic CISUS system along with other functionalities (i.e. dual view visualization, registration, real-time tracking, segmentation, etc) to rapidly create their medical/surgical applications. Our current driving clinical application is robotically assisted and freehand 3DUS-guided liver ablation, which is fully being integrated under the CISUS-3D Slicer. Initial functionality and pre-clinical feasibility are demonstrated on phantom and ex-vivo animal models.

  8. Application of 3D hydrodynamic and particle tracking models for better environmental management of finfish culture

    NASA Astrophysics Data System (ADS)

    Moreno Navas, Juan; Telfer, Trevor C.; Ross, Lindsay G.

    2011-04-01

    Hydrographic conditions, and particularly current speeds, have a strong influence on the management of fish cage culture. These hydrodynamic conditions can be used to predict particle movement within the water column and the results used to optimise environmental conditions for effective site selection, setting of environmental quality standards, waste dispersion, and potential disease transfer. To this end, a 3D hydrodynamic model, MOHID, has been coupled to a particle tracking model to study the effects of mean current speed, quiescent water periods and bulk water circulation in Mulroy Bay, Co. Donegal Ireland, an Irish fjard (shallow fjordic system) important to the aquaculture industry. A Lagangrian method simulated the instantaneous release of "particles" emulating discharge from finfish cages to show the behaviour of waste in terms of water circulation and water exchange. The 3D spatial models were used to identify areas of mixed and stratified water using a version of the Simpson-Hunter criteria, and to use this in conjunction with models of current flow for appropriate site selection for salmon aquaculture. The modelled outcomes for stratification were in good agreement with the direct measurements of water column stratification based on observed density profiles. Calculations of the Simpson-Hunter tidal parameter indicated that most of Mulroy Bay was potentially stratified with a well mixed region over the shallow channels where the water is faster flowing. The fjard was characterised by areas of both very low and high mean current speeds, with some areas having long periods of quiescent water. The residual current and the particle tracking animations created through the models revealed an anticlockwise eddy that may influence waste dispersion and potential for disease transfer, among salmon cages and which ensures that the retention time of waste substances from cages is extended. The hydrodynamic model results were incorporated into the ArcView TM GIS

  9. Using an Automated 3D-tracking System to Record Individual and Shoals of Adult Zebrafish

    PubMed Central

    Maaswinkel, Hans; Zhu, Liqun; Weng, Wei

    2013-01-01

    Like many aquatic animals, zebrafish (Danio rerio) moves in a 3D space. It is thus preferable to use a 3D recording system to study its behavior. The presented automatic video tracking system accomplishes this by using a mirror system and a calibration procedure that corrects for the considerable error introduced by the transition of light from water to air. With this system it is possible to record both single and groups of adult zebrafish. Before use, the system has to be calibrated. The system consists of three modules: Recording, Path Reconstruction, and Data Processing. The step-by-step protocols for calibration and using the three modules are presented. Depending on the experimental setup, the system can be used for testing neophobia, white aversion, social cohesion, motor impairments, novel object exploration etc. It is especially promising as a first-step tool to study the effects of drugs or mutations on basic behavioral patterns. The system provides information about vertical and horizontal distribution of the zebrafish, about the xyz-components of kinematic parameters (such as locomotion, velocity, acceleration, and turning angle) and it provides the data necessary to calculate parameters for social cohesions when testing shoals. PMID:24336189

  10. A new method for automatic tracking of facial landmarks in 3D motion captured images (4D).

    PubMed

    Al-Anezi, T; Khambay, B; Peng, M J; O'Leary, E; Ju, X; Ayoub, A

    2013-01-01

    The aim of this study was to validate the automatic tracking of facial landmarks in 3D image sequences. 32 subjects (16 males and 16 females) aged 18-35 years were recruited. 23 anthropometric landmarks were marked on the face of each subject with non-permanent ink using a 0.5mm pen. The subjects were asked to perform three facial animations (maximal smile, lip purse and cheek puff) from rest position. Each animation was captured by the 3D imaging system. A single operator manually digitised the landmarks on the 3D facial models and their locations were compared with those of the automatically tracked ones. To investigate the accuracy of manual digitisation, the operator re-digitised the same set of 3D images of 10 subjects (5 male and 5 female) at 1 month interval. The discrepancies in x, y and z coordinates between the 3D position of the manual digitised landmarks and that of the automatic tracked facial landmarks were within 0.17mm. The mean distance between the manually digitised and the automatically tracked landmarks using the tracking software was within 0.55 mm. The automatic tracking of facial landmarks demonstrated satisfactory accuracy which would facilitate the analysis of the dynamic motion during facial animations. PMID:23218511

  11. More IMPATIENT: A Gridding-Accelerated Toeplitz-based Strategy for Non-Cartesian High-Resolution 3D MRI on GPUs

    PubMed Central

    Gai, Jiading; Obeid, Nady; Holtrop, Joseph L.; Wu, Xiao-Long; Lam, Fan; Fu, Maojing; Haldar, Justin P.; Hwu, Wen-mei W.; Liang, Zhi-Pei; Sutton, Bradley P.

    2013-01-01

    Several recent methods have been proposed to obtain significant speed-ups in MRI image reconstruction by leveraging the computational power of GPUs. Previously, we implemented a GPU-based image reconstruction technique called the Illinois Massively Parallel Acquisition Toolkit for Image reconstruction with ENhanced Throughput in MRI (IMPATIENT MRI) for reconstructing data collected along arbitrary 3D trajectories. In this paper, we improve IMPATIENT by removing computational bottlenecks by using a gridding approach to accelerate the computation of various data structures needed by the previous routine. Further, we enhance the routine with capabilities for off-resonance correction and multi-sensor parallel imaging reconstruction. Through implementation of optimized gridding into our iterative reconstruction scheme, speed-ups of more than a factor of 200 are provided in the improved GPU implementation compared to the previous accelerated GPU code. PMID:23682203

  12. 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.

  13. The systematic and random errors determination using realtime 3D surface tracking system in breast cancer

    NASA Astrophysics Data System (ADS)

    Kanphet, J.; Suriyapee, S.; Dumrongkijudom, N.; Sanghangthum, T.; Kumkhwao, J.; Wisetrintong, M.

    2016-03-01

    The purpose of this study to determine the patient setup uncertainties in deep inspiration breath-hold (DIBH) radiation therapy for left breast cancer patients using real-time 3D surface tracking system. The six breast cancer patients treated by 6 MV photon beams from TrueBeam linear accelerator were selected. The patient setup errors and motion during treatment were observed and calculated for interfraction and intrafraction motions. The systematic and random errors were calculated in vertical, longitudinal and lateral directions. From 180 images tracking before and during treatment, the maximum systematic error of interfraction and intrafraction motions were 0.56 mm and 0.23 mm, the maximum random error of interfraction and intrafraction motions were 1.18 mm and 0.53 mm, respectively. The interfraction was more pronounce than the intrafraction, while the systematic error was less impact than random error. In conclusion the intrafraction motion error from patient setup uncertainty is about half of interfraction motion error, which is less impact due to the stability in organ movement from DIBH. The systematic reproducibility is also half of random error because of the high efficiency of modern linac machine that can reduce the systematic uncertainty effectively, while the random errors is uncontrollable.

  14. Eulerian and Lagrangian methods for vortex tracking in 2D and 3D flows

    NASA Astrophysics Data System (ADS)

    Huang, Yangzi; Green, Melissa

    2014-11-01

    Coherent structures are a key component of unsteady flows in shear layers. Improvement of experimental techniques has led to larger amounts of data and requires of automated procedures for vortex tracking. Many vortex criteria are Eulerian, and identify the structures by an instantaneous local swirling motion in the field, which are indicated by closed or spiral streamlines or pathlines in a reference frame. Alternatively, a Lagrangian Coherent Structures (LCS) analysis is a Lagrangian method based on the quantities calculated along fluid particle trajectories. In the current work, vortex detection is demonstrated on data from the simulation of two cases: a 2D flow with a flat plate undergoing a 45 ° pitch-up maneuver and a 3D wall-bounded turbulence channel flow. Vortices are visualized and tracked by their centers and boundaries using Γ1, the Q criterion, and LCS saddle points. In the cases of 2D flow, saddle points trace showed a rapid acceleration of the structure which indicates the shedding from the plate. For channel flow, saddle points trace shows that average structure convection speed exhibits a similar trend as a function of wall-normal distance as the mean velocity profile, and leads to statistical quantities of vortex dynamics. Dr. Jeff Eldredge and his research group at UCLA are gratefully acknowledged for sharing the database of simulation for the current research. This work was supported by the Air Force Office of Scientific Research under AFOSR Award No. FA9550-14-1-0210.

  15. 3-D Particle Tracking Velocimetry: Development and Applications in Small Scale Flows

    NASA Astrophysics Data System (ADS)

    Tien, Wei-Hsin

    The thesis contains two parts of studies. In part I, a novel volumetric velocimetry technique is developed to measure the 3-D flow field of small-scale flows. The technique utilizes a color-coded pinhole plate with multiple light sources aligned to each pinhole to achieve high particle image density and large measurable depth on a single lens microscope system. A color separation algorithm and an improved particle identification algorithm are developed to identify individual particle images from each pinhole view. Furthermore, a calibration-based technique based on epi-polar line search method is developed to reconstruct the spatial coordinates of the particle, and a new two-frame tracking particle-tracking algorithm is developed to calculate the velocity field. The system was setup to achieve a magnification of 2.69, resulting in an imaging volume of 3.35 x 2.5 x 1.5 mm3 and showed satisfactory measurement accuracy. The technique was then further miniaturized to achieve a magnification of 10, resulting in a imaging volume of 600 x 600 x 600 microm3. The system was applied to a backward-facing step flow to test its ability to reconstruct the unsteady flow field with two-frame tracking. Finally, this technique was applied to a steady streaming flow field in a microfluidic device used to trap particles. The results revealed the three-dimensional flow structure that has not been observed in previous studies, and provided insights to the design of a more efficient trapping device. In part II, an in-vitro study was carried out to investigate the flow around a prosthetic venous valve. Using 2-D PIV, the dynamics of the valve motion was captured and the velocity fields were measured to investigate the effect of the sinus pocket and the coupling effect of a pair of valves. The PIV and hemodynamic results showed that the sinus pocket around the valve functioned as a flow regulator to smooth the entrained velocity profile and suppress the jet width. For current prosthetic

  16. Confocal fluorometer for diffusion tracking in 3D engineered tissue constructs

    NASA Astrophysics Data System (ADS)

    Daly, D.; Zilioli, A.; Tan, N.; Buttenschoen, K.; Chikkanna, B.; Reynolds, J.; Marsden, B.; Hughes, C.

    2016-03-01

    We present results of the development of a non-contacting instrument, called fScan, based on scanning confocal fluorometry for assessing the diffusion of materials through a tissue matrix. There are many areas in healthcare diagnostics and screening where it is now widely accepted that the need for new quantitative monitoring technologies is a major pinch point in patient diagnostics and in vitro testing. With the increasing need to interpret 3D responses this commonly involves the need to track the diffusion of compounds, pharma-active species and cells through a 3D matrix of tissue. Methods are available but to support the advances that are currently only promised, this monitoring needs to be real-time, non-invasive, and economical. At the moment commercial meters tend to be invasive and usually require a sample of the medium to be removed and processed prior to testing. This methodology clearly has a number of significant disadvantages. fScan combines a fiber based optical arrangement with a compact, free space optical front end that has been integrated so that the sample's diffusion can be measured without interference. This architecture is particularly important due to the "wet" nature of the samples. fScan is designed to measure constructs located within standard well plates and a 2-D motion stage locates the required sample with respect to the measurement system. Results are presented that show how the meter has been used to evaluate movements of samples through collagen constructs in situ without disturbing their kinetic characteristics. These kinetics were little understood prior to these measurements.

  17. Performance of ultrasound based measurement of 3D displacement using a curvilinear probe for organ motion tracking

    NASA Astrophysics Data System (ADS)

    Harris, Emma J.; Miller, Naomi R.; Bamber, Jeffrey C.; Evans, Phillip M.; Symonds-Tayler, J. Richard N.

    2007-09-01

    Three-dimensional (3D) soft tissue tracking is of interest for monitoring organ motion during therapy. Our goal is to assess the tracking performance of a curvilinear 3D ultrasound probe in terms of the accuracy and precision of measured displacements. The first aim was to examine the depth dependence of the tracking performance. This is of interest because the spatial resolution varies with distance from the elevational focus and because the curvilinear geometry of the transducer causes the spatial sampling frequency to decrease with depth. Our second aim was to assess tracking performance as a function of the spatial sampling setting (low, medium or high sampling). These settings are incorporated onto 3D ultrasound machines to allow the user to control the trade-off between spatial sampling and temporal resolution. Volume images of a speckle-producing phantom were acquired before and after the probe had been moved by a known displacement (1, 2 or 8 mm). This allowed us to assess the optimum performance of the tracking algorithm, in the absence of motion. 3D speckle tracking was performed using 3D cross-correlation and sub-voxel displacements were estimated. The tracking performance was found to be best for axial displacements and poorest for elevational displacements. In general, the performance decreased with depth, although the nature of the depth dependence was complex. Under certain conditions, the tracking performance was sufficient to be useful for monitoring organ motion. For example, at the highest sampling setting, for a 2 mm displacement, good accuracy and precision (an error and standard deviation of <0.4 mm) were observed at all depths and for all directions of displacement. The trade-off between spatial sampling, temporal resolution and size of the field of view (FOV) is discussed.

  18. Automated 3D Motion Tracking using Gabor Filter Bank, Robust Point Matching, and Deformable Models

    PubMed Central

    Wang, Xiaoxu; Chung, Sohae; Metaxas, Dimitris; Axel, Leon

    2013-01-01

    Tagged Magnetic Resonance Imaging (tagged MRI or tMRI) provides a means of directly and noninvasively displaying the internal motion of the myocardium. Reconstruction of the motion field is needed to quantify important clinical information, e.g., the myocardial strain, and detect regional heart functional loss. In this paper, we present a three-step method for this task. First, we use a Gabor filter bank to detect and locate tag intersections in the image frames, based on local phase analysis. Next, we use an improved version of the Robust Point Matching (RPM) method to sparsely track the motion of the myocardium, by establishing a transformation function and a one-to-one correspondence between grid tag intersections in different image frames. In particular, the RPM helps to minimize the impact on the motion tracking result of: 1) through-plane motion, and 2) relatively large deformation and/or relatively small tag spacing. In the final step, a meshless deformable model is initialized using the transformation function computed by RPM. The model refines the motion tracking and generates a dense displacement map, by deforming under the influence of image information, and is constrained by the displacement magnitude to retain its geometric structure. The 2D displacement maps in short and long axis image planes can be combined to drive a 3D deformable model, using the Moving Least Square method, constrained by the minimization of the residual error at tag intersections. The method has been tested on a numerical phantom, as well as on in vivo heart data from normal volunteers and heart disease patients. The experimental results show that the new method has a good performance on both synthetic and real data. Furthermore, the method has been used in an initial clinical study to assess the differences in myocardial strain distributions between heart disease (left ventricular hypertrophy) patients and the normal control group. The final results show that the proposed method

  19. Towards intraoperative monitoring of ablation using tracked 3D ultrasound elastography and internal palpation

    NASA Astrophysics Data System (ADS)

    Foroughi, Pezhman; Burgner, Jessica; Choti, Michael A.; Webster, Robert J., III; Hager, Gregory D.; Boctor, Emad M.

    2012-03-01

    B-mode ultrasound is widely used in liver ablation. However, the necrosis zone is typically not visible under b-mode ultrasound, since ablation does not necessarily change the acoustic properties of the tissue. In contrast, the change in tissue stiffness makes elastography ideal for monitoring ablation. Tissue palpation for elastography is typically applied at the imaging probe, by indenting it slightly into the tissue surface. However, in this paper we propose an alternate approach, where palpation is applied by a surgical instrument located inside the tissue. In our approach, the ablation needle is placed inside a steerable device called an active cannula and inserted into the tissue. A controlled motion is applied to the center of the ablation zone via the active cannula. Since the type and direction of motion is known, displacement can then be computed from two frames with the desired motion. The elastography results show the ablated region around the needle. While internal palpation provides excellent local contrast, freehand palpation from outside of the tissue via the transducer can provide a more global view of the region of the interest. For this purpose, we used a tracked 3D transducer to generate volumetric elastography images covering the ablated region. The tracking information is employed to improve the elastography results by selecting volume pairs suitable for elastography. This is an extension of our 2D frame selection technique which can cope with uncertainties associated with intra-operative elastography. In our experiments with phantom and ex-vivo tissue, we were able to generate high-quality images depicting the boundaries of the hard lesions.

  20. 3D Joint Speaker Position and Orientation Tracking with Particle Filters

    PubMed Central

    Segura, Carlos; Hernando, Javier

    2014-01-01

    This paper addresses the problem of three-dimensional speaker orientation estimation in a smart-room environment equipped with microphone arrays. A Bayesian approach is proposed to jointly track the location and orientation of an active speaker. The main motivation is that the knowledge of the speaker orientation may yield an increased localization performance and vice versa. Assuming that the sound produced by the speaker is originated from his mouth, the center of the head is deduced based on the estimated head orientation. Moreover, the elevation angle of the head of the speaker can be partly inferred from the fast vertical movements of the computed mouth location. In order to test the performance of the proposed algorithm, a new multimodal dataset has been recorded for this purpose, where the corresponding 3D orientation angles are acquired by an inertial measurement unit (IMU) provided by accelerometers, magnetometers and gyroscopes in the three-axes. The proposed joint algorithm outperforms a two-step approach in terms of localization and orientation angle precision assessing the superiority of the joint approach. PMID:24481230

  1. 3D joint speaker position and orientation tracking with particle filters.

    PubMed

    Segura, Carlos; Hernando, Javier

    2014-01-01

    This paper addresses the problem of three-dimensional speaker orientation estimation in a smart-room environment equipped with microphone arrays. A Bayesian approach is proposed to jointly track the location and orientation of an active speaker. The main motivation is that the knowledge of the speaker orientation may yield an increased localization performance and vice versa. Assuming that the sound produced by the speaker is originated from his mouth, the center of the head is deduced based on the estimated head orientation. Moreover, the elevation angle of the head of the speaker can be partly inferred from the fast vertical movements of the computed mouth location. In order to test the performance of the proposed algorithm, a new multimodal dataset has been recorded for this purpose, where the corresponding 3D orientation angles are acquired by an inertial measurement unit (IMU) provided by accelerometers, magnetometers and gyroscopes in the three-axes. The proposed joint algorithm outperforms a two-step approach in terms of localization and orientation angle precision assessing the superiority of the joint approach. PMID:24481230

  2. Fast, automatic, and accurate catheter reconstruction in HDR brachytherapy using an electromagnetic 3D tracking system

    SciTech Connect

    Poulin, Eric; Racine, Emmanuel; Beaulieu, Luc; Binnekamp, Dirk

    2015-03-15

    Purpose: In high dose rate brachytherapy (HDR-B), current catheter reconstruction protocols are relatively slow and error prone. The purpose of this technical note is to evaluate the accuracy and the robustness of an electromagnetic (EM) tracking system for automated and real-time catheter reconstruction. Methods: For this preclinical study, a total of ten catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a 18G biopsy needle, used as an EM stylet and equipped with a miniaturized sensor, and the second generation Aurora{sup ®} Planar Field Generator from Northern Digital Inc. The Aurora EM system provides position and orientation value with precisions of 0.7 mm and 0.2°, respectively. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical computed tomography (CT) system with a spatial resolution of 89 μm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, five catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 s, leading to a total reconstruction time inferior to 3 min for a typical 17-catheter implant. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.66 ± 0.33 mm and 1.08 ± 0.72 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be more accurate. A maximum difference of less than 0.6 mm was found between successive EM reconstructions. Conclusions: The EM reconstruction was found to be more accurate and precise than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators.

  3. Mapping 3D Strains with Ultrasound Speckle Tracking: Method Validation and Initial Results in Porcine Scleral Inflation.

    PubMed

    Cruz Perez, Benjamin; Pavlatos, Elias; Morris, Hugh J; Chen, Hong; Pan, Xueliang; Hart, Richard T; Liu, Jun

    2016-07-01

    This study aimed to develop and validate a high frequency ultrasound method for measuring distributive, 3D strains in the sclera during elevations of intraocular pressure. A 3D cross-correlation based speckle-tracking algorithm was implemented to compute the 3D displacement vector and strain tensor at each tracking point. Simulated ultrasound radiofrequency data from a sclera-like structure at undeformed and deformed states with known strains were used to evaluate the accuracy and signal-to-noise ratio (SNR) of strain estimation. An experimental high frequency ultrasound (55 MHz) system was built to acquire 3D scans of porcine eyes inflated from 15 to 17 and then 19 mmHg. Simulations confirmed good strain estimation accuracy and SNR (e.g., the axial strains had less than 4.5% error with SNRs greater than 16.5 for strains from 0.005 to 0.05). Experimental data in porcine eyes showed increasing tensile, compressive, and shear strains in the posterior sclera during inflation, with a volume ratio close to one suggesting near-incompressibility. This study established the feasibility of using high frequency ultrasound speckle tracking for measuring 3D tissue strains and its potential to characterize physiological deformations in the posterior eye. PMID:26563101

  4. A novel 3D micron-scale DPTV (Defocused Particle Tracking Velocimetry) and its applications in microfluidic devices

    NASA Astrophysics Data System (ADS)

    Roberts, John

    2005-11-01

    The rapid advancements in micro/nano biotechnology demand quantitative tools for characterizing microfluidic flows in lab-on-a-chip applications, validation of computational results for fully 3D flows in complex micro-devices, and efficient observation of cellular dynamics in 3D. We present a novel 3D micron-scale DPTV (defocused particle tracking velocimetry) that is capable of mapping out 3D Lagrangian, as well as 3D Eulerian velocity flow fields at sub-micron resolution and with one camera. The main part of the imaging system is an epi-fluorescent microscope (Olympus IX 51), and the seeding particles are fluorescent particles with diameter range 300nm - 10um. A software package has been developed for identifying (x,y,z,t) coordinates of the particles using the defocused images. Using the imaging system, we successfully mapped the pressure driven flow fields in microfluidic channels. In particular, we measured the Laglangian flow fields in a microfluidic channel with a herring bone pattern at the bottom, the later is used to enhance fluid mixing in lateral directions. The 3D particle tracks revealed the flow structure that has only been seen in numerical computation. This work is supported by the National Science Foundation (CTS - 0514443), the Nanobiotechnology Center at Cornell, and The New York State Center for Life Science Enterprise.

  5. Tracking of cracks in bridges using GPR: a 3D approach

    NASA Astrophysics Data System (ADS)

    Benedetto, A.

    2012-04-01

    Corrosion associated with reinforcing bars is the most significant contributor to bridge deficiencies. The corrosion is usually caused by moisture and chloride ion exposure. In particular, corrosion products FeO, Fe2O3, Fe3O4 and other oxides along reinforcement bars. The reinforcing bars are attacked by corrosion and yield expansive corrosion products. These oxidation products occupy a larger volume than the original intact steel and internal expansive stresses lead to cracking and debonding. There are some conventional inspection methods for detection of reinforcing bar corrosion but they can be invasive and destructive, often laborious, lane closures is required and it is difficult or unreliable any quantification of corrosion. For these reasons, bridge engineers are always more preferring to use the Ground Penetrating Radar (GPR) technique. In this work a novel numerical approach for three dimensional tracking and mapping of cracks in the bridge is proposed. The work starts from some interesting results based on the use of the 3D imaging technique in order to improve the potentiality of GPR to detect voids, cracks or buried object. The numerical approach has been tested on data acquired on some bridges using a pulse GPR system specifically designed for bridge deck and pavement inspection that is called RIS Hi Bright. The equipment integrates two arrays of Ultra Wide Band ground coupled antennas, having a main working frequency of 2 GHz. The two arrays within the RIS Hi Bright are using antennas arranged with different polarization. One array includes sensors with parallel polarization with respect to the scanning direction (VV array), the other has sensors in orthogonal polarization (HH array). Overall the system collects 16 profiles within a single scan (8 HH + 8 VV). The cracks, associated often to moisture increasing and higher values of the dielectric constant, produce a not negligible increasing of the signal amplitude. Following this, the algorithm

  6. Rapid, High-Throughput Tracking of Bacterial Motility in 3D via Phase-Contrast Holographic Video Microscopy

    PubMed Central

    Cheong, Fook Chiong; Wong, Chui Ching; Gao, YunFeng; Nai, Mui Hoon; Cui, Yidan; Park, Sungsu; Kenney, Linda J.; Lim, Chwee Teck

    2015-01-01

    Tracking fast-swimming bacteria in three dimensions can be extremely challenging with current optical techniques and a microscopic approach that can rapidly acquire volumetric information is required. Here, we introduce phase-contrast holographic video microscopy as a solution for the simultaneous tracking of multiple fast moving cells in three dimensions. This technique uses interference patterns formed between the scattered and the incident field to infer the three-dimensional (3D) position and size of bacteria. Using this optical approach, motility dynamics of multiple bacteria in three dimensions, such as speed and turn angles, can be obtained within minutes. We demonstrated the feasibility of this method by effectively tracking multiple bacteria species, including Escherichia coli, Agrobacterium tumefaciens, and Pseudomonas aeruginosa. In addition, we combined our fast 3D imaging technique with a microfluidic device to present an example of a drug/chemical assay to study effects on bacterial motility. PMID:25762336

  7. A Framework for 3D Model-Based Visual Tracking Using a GPU-Accelerated Particle Filter.

    PubMed

    Brown, J A; Capson, D W

    2012-01-01

    A novel framework for acceleration of particle filtering approaches to 3D model-based, markerless visual tracking in monocular video is described. Specifically, we present a methodology for partitioning and mapping the computationally expensive weight-update stage of a particle filter to a graphics processing unit (GPU) to achieve particle- and pixel-level parallelism. Nvidia CUDA and Direct3D are employed to harness the massively parallel computational power of modern GPUs for simulation (3D model rendering) and evaluation (segmentation, feature extraction, and weight calculation) of hundreds of particles at high speeds. The proposed framework addresses the computational intensity that is intrinsic to all particle filter approaches, including those that have been modified to minimize the number of particles required for a particular task. Performance and tracking quality results for rigid object and articulated hand tracking experiments demonstrate markerless, model-based visual tracking on consumer-grade graphics hardware with pixel-level accuracy up to 95 percent at 60+ frames per second. The framework accelerates particle evaluation up to 49 times over a comparable CPU-only implementation, providing an increased particle count while maintaining real-time frame rates. PMID:21301027

  8. Model-based lasso catheter tracking in monoplane fluoroscopy for 3D breathing motion compensation during EP procedures

    NASA Astrophysics Data System (ADS)

    Liao, Rui

    2010-02-01

    Radio-frequency catheter ablation (RFCA) of the pulmonary veins (PVs) attached to the left atrium (LA) is usually carried out under fluoroscopy guidance. Overlay of detailed anatomical structures via 3-D CT and/or MR volumes onto the fluoroscopy helps visualization and navigation in electrophysiology procedures (EP). Unfortunately, respiratory motion may impair the utility of static overlay of the volume with fluoroscopy for catheter navigation. In this paper, we propose a B-spline based method for tracking the circumferential catheter (lasso catheter) in monoplane fluoroscopy. The tracked motion can be used for the estimation of the 3-D trajectory of breathing motion and for subsequent motion compensation. A lasso catheter is typically used during EP procedures and is pushed against the ostia of the PVs to be ablated. Hence this method does not require additional instruments, and achieves motion estimation right at the site of ablation. The performance of the proposed tracking algorithm was evaluated on 340 monoplane frames with an average error of 0.68 +/- 0.36 mms. Our contributions in this work are twofold. First and foremost, we show how to design an effective, practical, and workflow-friendly 3-D motion compensation scheme for EP procedures in a monoplane setup. In addition, we develop an efficient and accurate method for model-based tracking of the circumferential lasso catheter in the low-dose EP fluoroscopy.

  9. 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

  10. MetaTracker: integration and abstraction of 3D motion tracking data from multiple hardware systems

    NASA Astrophysics Data System (ADS)

    Kopecky, Ken; Winer, Eliot

    2014-06-01

    Motion tracking has long been one of the primary challenges in mixed reality (MR), augmented reality (AR), and virtual reality (VR). Military and defense training can provide particularly difficult challenges for motion tracking, such as in the case of Military Operations in Urban Terrain (MOUT) and other dismounted, close quarters simulations. These simulations can take place across multiple rooms, with many fast-moving objects that need to be tracked with a high degree of accuracy and low latency. Many tracking technologies exist, such as optical, inertial, ultrasonic, and magnetic. Some tracking systems even combine these technologies to complement each other. However, there are no systems that provide a high-resolution, flexible, wide-area solution that is resistant to occlusion. While frameworks exist that simplify the use of tracking systems and other input devices, none allow data from multiple tracking systems to be combined, as if from a single system. In this paper, we introduce a method for compensating for the weaknesses of individual tracking systems by combining data from multiple sources and presenting it as a single tracking system. Individual tracked objects are identified by name, and their data is provided to simulation applications through a server program. This allows tracked objects to transition seamlessly from the area of one tracking system to another. Furthermore, it abstracts away the individual drivers, APIs, and data formats for each system, providing a simplified API that can be used to receive data from any of the available tracking systems. Finally, when single-piece tracking systems are used, those systems can themselves be tracked, allowing for real-time adjustment of the trackable area. This allows simulation operators to leverage limited resources in more effective ways, improving the quality of training.

  11. Atmospheric Motion Vectors from INSAT-3D: Initial quality assessment and its impact on track forecast of cyclonic storm NANAUK

    NASA Astrophysics Data System (ADS)

    Deb, S. K.; Kishtawal, C. M.; Kumar, Prashant; Kiran Kumar, A. S.; Pal, P. K.; Kaushik, Nitesh; Sangar, Ghansham

    2016-03-01

    The advanced Indian meteorological geostationary satellite INSAT-3D was launched on 26 July 2013 with an improved imager and an infrared sounder and is placed at 82°E over the Indian Ocean region. With the advancement in retrieval techniques of different atmospheric parameters and with improved imager data have enhanced the scope for better understanding of the different tropical atmospheric processes over this region. The retrieval techniques and accuracy of one such parameter, Atmospheric Motion Vectors (AMV) has improved significantly with the availability of improved spatial resolution data along with more options of spectral channels in the INSAT-3D imager. The present work is mainly focused on providing brief descriptions of INSAT-3D data and AMV derivation processes using these data. It also discussed the initial quality assessment of INSAT-3D AMVs for a period of six months starting from 01 February 2014 to 31 July 2014 with other independent observations: i) Meteosat-7 AMVs available over this region, ii) in-situ radiosonde wind measurements, iii) cloud tracked winds from Multi-angle Imaging Spectro-Radiometer (MISR) and iv) numerical model analysis. It is observed from this study that the qualities of newly derived INSAT-3D AMVs are comparable with existing two versions of Meteosat-7 AMVs over this region. To demonstrate its initial application, INSAT-3D AMVs are assimilated in the Weather Research and Forecasting (WRF) model and it is found that the assimilation of newly derived AMVs has helped in reduction of track forecast errors of the recent cyclonic storm NANAUK over the Arabian Sea. Though, the present study is limited to its application to one case study, however, it will provide some guidance to the operational agencies for implementation of this new AMV dataset for future applications in the Numerical Weather Prediction (NWP) over the south Asia region.

  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. Multi-modality fusion of CT, 3D ultrasound, and tracked strain images for breast irradiation planning

    NASA Astrophysics Data System (ADS)

    Foroughi, Pezhman; Csoma, Csaba; Rivaz, Hassan; Fichtinger, Gabor; Zellars, Richard; Hager, Gregory; Boctor, Emad

    2009-02-01

    Breast irradiation significantly reduces the risk of recurrence of cancer. There is growing evidence suggesting that irradiation of only the involved area of the breast, partial breast irradiation (PBI), is as effective as whole breast irradiation. Benefits of PBI include shortened treatment time, and perhaps fewer side effects as less tissue is treated. However, these benefits cannot be realized without precise and accurate localization of the lumpectomy cavity. Several studies have shown that accurate delineation of the cavity in CT scans is very challenging and the delineated volumes differ dramatically over time and among users. In this paper, we propose utilizing 3D ultrasound (3D-US) and tracked strain images as complementary modalities to reduce uncertainties associated with current CT planning workflow. We present the early version of an integrated system that fuses 3D-US and real-time strain images. For the first time, we employ tracking information to reduce the noise in calculation of strain image by choosing the properly compressed frames and to position the strain image within the ultrasound volume. Using this system, we provide the tools to retrieve additional information from 3D-US and strain image alongside the CT scan. We have preliminarily evaluated our proposed system in a step-by-step fashion using a breast phantom and clinical experiments.

  14. Shape measurement by a multi-view methodology based on the remote tracking of a 3D optical scanner

    NASA Astrophysics Data System (ADS)

    Barone, Sandro; Paoli, Alessandro; Viviano Razionale, Armando

    2012-03-01

    Full field optical techniques can be reliably used for 3D measurements of complex shapes by multi-view processes, which require the computation of transformation parameters relating different views into a common reference system. Although, several multi-view approaches have been proposed, the alignment process is still the crucial step of a shape reconstruction. In this paper, a methodology to automatically align 3D views has been developed by integrating a stereo vision system and a full field optical scanner. In particular, the stereo vision system is used to remotely track the optical scanner within a working volume. The tracking system uses stereo images to detect the 3D coordinates of retro-reflective infrared markers rigidly connected to the scanner. Stereo correspondences are established by a robust methodology based on combining the epipolar geometry with an image spatial transformation constraint. The proposed methodology has been validated by experimental tests regarding both the evaluation of the measurement accuracy and the 3D reconstruction of an industrial shape.

  15. A new 3D tracking method for cell mechanics investigation exploiting the capabilities of digital holography in microscopy

    NASA Astrophysics Data System (ADS)

    Miccio, L.; Memmolo, P.; Merola, F.; Fusco, S.; Netti, P. A.; Ferraro, P.

    2014-03-01

    A method for 3D tracking has been developed exploiting Digital Holography features in Microscopy (DHM). In the framework of self-consistent platform for manipulation and measurement of biological specimen we use DHM for quantitative and completely label free analysis of samples with low amplitude contrast. Tracking capability extend the potentiality of DHM allowing to monitor the motion of appropriate probes and correlate it with sample properties. Complete 3D tracking has been obtained for the probes avoiding the amplitude refocusing in traditional tracking processes. Moreover, in biology and biomedical research fields one of the main topic is the understanding of morphology and mechanics of cells and microorganisms. Biological samples present low amplitude contrast that limits the information that can be retrieved through optical bright-field microscope measurements. The main effect on light propagating in such objects is in phase. This is known as phase-retardation or phase-shift. DHM is an innovative and alternative approach in microscopy, it's a good candidate for no-invasive and complete specimen analysis because its main characteristic is the possibility to discern between intensity and phase information performing quantitative mapping of the Optical Path Length. In this paper, the flexibility of DH is employed to analyze cell mechanics of unstained cells subjected to appropriate stimuli. DHM is used to measure all the parameters useful to understand the deformations induced by external and controlled stresses on in-vitro cells. Our configuration allows 3D tracking of micro-particles and, simultaneously, furnish quantitative phase-contrast maps. Experimental results are presented and discussed for in vitro cells.

  16. 3D tracking and phase-contrast imaging by twin-beams digital holographic microscope in microfluidics

    NASA Astrophysics Data System (ADS)

    Miccio, L.; Memmolo, P.; Finizio, A.; Paturzo, M.; Merola, F.; Grilli, S.; Ferraro, P.

    2012-06-01

    A compact twin-beam interferometer that can be adopted as a flexible diagnostic tool in microfluidic platforms is presented. The devise has two functionalities, as explained in the follow, and can be easily integrated in microfluidic chip. The configuration allows 3D tracking of micro-particles and, at same time, furnishes Quantitative Phase-Contrast maps of tracked micro-objects by interference microscopy. Experimental demonstration of its effectiveness and compatibility with biological field is given on for in vitro cells in microfluidic environment. Nowadays, several microfluidic configuration exist and many of them are commercially available, their development is due to the possibility for manipulating droplets, handling micro and nano-objects, visualize and quantify processes occurring in small volumes and, clearly, for direct applications on lab-on-a chip devices. In microfluidic research field, optical/photonics approaches are the more suitable ones because they have various advantages as to be non-contact, full-field, non-invasive and can be packaged thanks to the development of integrable optics. Moreover, phase contrast approaches, adapted to a lab-on-a-chip configurations, give the possibility to get quantitative information with remarkable lateral and vertical resolution directly in situ without the need to dye and/or kill cells. Furthermore, numerical techniques for tracking of micro-objects needs to be developed for measuring velocity fields, trajectories patterns, motility of cancer cell and so on. Here, we present a compact holographic microscope that can ensure, by the same configuration and simultaneously, accurate 3D tracking and quantitative phase-contrast analysis. The system, simple and solid, is based on twin laser beams coming from a single laser source. Through a easy conceptual design, we show how these two different functionalities can be accomplished by the same optical setup. The working principle, the optical setup and the mathematical

  17. Digital In-Line Holography System for 3D-3C Particle Tracking Velocimetry

    NASA Astrophysics Data System (ADS)

    Malek, Mokrane; Lebrun, Denis; Allano, Daniel

    Digital in-line holography is a suitable method for measuring three dimensional (3D) velocity fields. Such a system records directly on a charge-coupled device (CCD) camera a couple of diffraction patterns produced by small particles illuminated by a modulated laser diode. The numerical reconstruction is based on the wavelet transformation method. A 3D particle field is reconstructed by computing the wavelet components for different scale parameters. The scale parameter is directly related to the axial distance between a given particle and the CCD camera. The particle images are identified and localized by analyzing the maximum of the wavelet transform modulus (WTMM) and the equivalent diameter of the particle image (Deq). Afterwards, a 3D point-matching (PM) algorithm is applied to the pair of sets containing the 3D particle locations. In the PM algorithm, the displacement of the particles is modeled by an affine transformation. This affine transformation is based on the use of the dual number quaternions. Afterwards, the velocity-field extraction is performed. This system is tested with simulated particle field displacements and the feasibility is checked with an experimental displacement.

  18. 3D positional tracking of ellipsoidal particles in a microtube flow using holographic microscopy

    NASA Astrophysics Data System (ADS)

    Byeon, Hyeok Jun; Seo, Kyung Won; Lee, Sang Joon

    2014-11-01

    Understanding of micro-scale flow phenomena is getting large attention under advances in micro-scale measurement technologies. Especially, the dynamics of particles suspended in a fluid is essential in both scientific and industrial fields. Moreover, most particles handled in research and industrial fields have non-spherical shapes rather than a simple spherical shape. Under various flow conditions, these non-spherical particles exhibit unique dynamic behaviors. To analyze these dynamic behaviors in a fluid flow, 3D positional information of the particles should be measured accurately. In this study, digital holographic microscopy (DHM) is employed to measure the 3D positional information of non-spherical particles, which are fabricated by stretching spherical polystyrene particles. 3D motions of those particles are obtained by interpreting the holograms captured from particles. Ellipsoidal particles with known size and shape are observed to verify the performance of the DHM technique. In addition, 3D positions of particles in a microtube flow are traced. This DHM technique exhibits promising potential in the analysis of dynamic behaviors of non-spherical particles suspended in micro-scale fluid flows.

  19. Rapid 3D Track Reconstruction with the BaBar Trigger Upgrade

    SciTech Connect

    Bailey, S

    2004-05-24

    A new hardware trigger system based on tracks detected by a stereo drift chamber has been developed for the BABAR experiment at the Stanford Linear Accelerator Center. The z{sub 0} p{sub T} Discriminator (ZPD) is capable of fast, 3-dimensional reconstruction of charged particle tracks and provides rejection of background events due to beam particles interacting with the beam pipe at the first-level trigger. Over 1 gigabyte of data is processed per second by each ZPD module. Rapid track reconstruction has been realized using Xilinx Virtex-II FPGAs.

  20. The Complete (3-D) Co-Seismic Displacements Using Point-Like Targets Tracking With Ascending And Descending SAR Data

    NASA Astrophysics Data System (ADS)

    Hu, Xie; Wang, Teng; Liao, Mingsheng

    2013-12-01

    SAR Interferometry (InSAR) has its unique advantages, e.g., all weather/time accessibility, cm-level accuracy and large spatial coverage, however, it can only obtain one dimensional measurement along line-of-sight (LOS) direction. Offset tracking is an important complement to measure large and rapid displacements in both azimuth and range directions. Here we perform offset tracking on detected point-like targets (PT) by calculating the cross-correlation with a sinc-like template. And a complete 3-D displacement field can be derived using PT offset tracking from a pair of ascending and descending data. The presented case study on 2010 M7.2 El Mayor-Cucapah earthquake helps us better understand the rupture details.

  1. Feasibility of low-dose single-view 3D fiducial tracking concurrent with external beam delivery

    SciTech Connect

    Speidel, Michael A.; Wilfley, Brian P.; Hsu, Annie; Hristov, Dimitre

    2012-04-15

    Purpose: In external-beam radiation therapy, existing on-board x-ray imaging chains orthogonal to the delivery beam cannot recover 3D target trajectories from a single view in real-time. This limits their utility for real-time motion management concurrent with beam delivery. To address this limitation, the authors propose a novel concept for on-board imaging based on the inverse-geometry Scanning-Beam Digital X-ray (SBDX) system and evaluate its feasibility for single-view 3D intradelivery fiducial tracking. Methods: A chest phantom comprising a posterior wall, a central lung volume, and an anterior wall was constructed. Two fiducials were placed along the mediastinal ridge between the lung cavities: a 1.5 mm diameter steel sphere superiorly and a gold cylinder (2.6 mm length x 0.9 mm diameter) inferiorly. The phantom was placed on a linear motion stage that moved sinusoidally. Fiducial motion was along the source-detector (z) axis of the SBDX system with {+-}10 mm amplitude and a programmed period of either 3.5 s or 5 s. The SBDX system was operated at 15 frames per second, 100 kVp, providing good apparent conspicuity of the fiducials. With the stage moving, detector data were acquired and subsequently reconstructed into 15 planes with a 12 mm plane-to-plane spacing using digital tomosynthesis. A tracking algorithm was applied to the image planes for each temporal frame to determine the position of each fiducial in (x,y,z)-space versus time. A 3D time-sinusoidal motion model was fit to the measured 3D coordinates and root mean square (RMS) deviations about the fitted trajectory were calculated. Results: Tracked motion was sinusoidal and primarily along the source-detector (z) axis. The RMS deviation of the tracked z-coordinate ranged from 0.53 to 0.71 mm. The motion amplitude derived from the model fit agreed with the programmed amplitude to within 0.28 mm for the steel sphere and within -0.77 mm for the gold seed. The model fit periods agreed with the programmed

  2. 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.

  3. Targets For Three-Dimensional (3-D) Tracking Of Human Impact Test Subjects

    NASA Astrophysics Data System (ADS)

    Muzzy, William H.; Prell, Arthur M.

    1982-02-01

    Lightweight targets mounted on the head and neck of human volunteers are photographed by high-speed cameras during impact acceleration tests. The targets must be capable of being tracked through a wide angular motion by at least two cameras to obtain three-dimens-ional displacement and orientation. Because the targets are tracked and digitized by a computerized photodigitizer, their pattern must be selected to maximize recognition and minimize crossover confusion. This pater discusses the target construction, orientation on the accelerometer mount, pattern selection, and paint scheme.

  4. Prediction of 3D internal organ position from skin surface motion: results from electromagnetic tracking studies

    NASA Astrophysics Data System (ADS)

    Wong, Kenneth H.; Tang, Jonathan; Zhang, Hui J.; Varghese, Emmanuel; Cleary, Kevin R.

    2005-04-01

    An effective treatment method for organs that move with respiration (such as the lungs, pancreas, and liver) is a major goal of radiation medicine. In order to treat such tumors, we need (1) real-time knowledge of the current location of the tumor, and (2) the ability to adapt the radiation delivery system to follow this constantly changing location. In this study, we used electromagnetic tracking in a swine model to address the first challenge, and to determine if movement of a marker attached to the skin could accurately predict movement of an internal marker embedded in an organ. Under approved animal research protocols, an electromagnetically tracked needle was inserted into a swine liver and an electromagnetically tracked guidewire was taped to the abdominal skin of the animal. The Aurora (Northern Digital Inc., Waterloo, Canada) electromagnetic tracking system was then used to monitor the position of both of these sensors every 40 msec. Position readouts from the sensors were then tested to see if any of the movements showed correlation. The strongest correlations were observed between external anterior-posterior motion and internal inferior-superior motion, with many other axes exhibiting only weak correlation. We also used these data to build a predictive model of internal motion by taking segments from the data and using them to derive a general functional relationship between the internal needle and the external guidewire. For the axis with the strongest correlation, this model enabled us to predict internal organ motion to within 1 mm.

  5. A maximum likelihood approach to diffeomorphic speckle tracking for 3D strain estimation in echocardiography.

    PubMed

    Curiale, Ariel H; Vegas-Sánchez-Ferrero, Gonzalo; Bosch, Johan G; Aja-Fernández, Santiago

    2015-08-01

    The strain and strain-rate measures are commonly used for the analysis and assessment of regional myocardial function. In echocardiography (EC), the strain analysis became possible using Tissue Doppler Imaging (TDI). Unfortunately, this modality shows an important limitation: the angle between the myocardial movement and the ultrasound beam should be small to provide reliable measures. This constraint makes it difficult to provide strain measures of the entire myocardium. Alternative non-Doppler techniques such as Speckle Tracking (ST) can provide strain measures without angle constraints. However, the spatial resolution and the noisy appearance of speckle still make the strain estimation a challenging task in EC. Several maximum likelihood approaches have been proposed to statistically characterize the behavior of speckle, which results in a better performance of speckle tracking. However, those models do not consider common transformations to achieve the final B-mode image (e.g. interpolation). This paper proposes a new maximum likelihood approach for speckle tracking which effectively characterizes speckle of the final B-mode image. Its formulation provides a diffeomorphic scheme than can be efficiently optimized with a second-order method. The novelty of the method is threefold: First, the statistical characterization of speckle generalizes conventional speckle models (Rayleigh, Nakagami and Gamma) to a more versatile model for real data. Second, the formulation includes local correlation to increase the efficiency of frame-to-frame speckle tracking. Third, a probabilistic myocardial tissue characterization is used to automatically identify more reliable myocardial motions. The accuracy and agreement assessment was evaluated on a set of 16 synthetic image sequences for three different scenarios: normal, acute ischemia and acute dyssynchrony. The proposed method was compared to six speckle tracking methods. Results revealed that the proposed method is the most

  6. Laetoli's lost tracks: 3D generated mean shape and missing footprints.

    PubMed

    Bennett, M R; Reynolds, S C; Morse, S A; Budka, M

    2016-01-01

    The Laetoli site (Tanzania) contains the oldest known hominin footprints, and their interpretation remains open to debate, despite over 35 years of research. The two hominin trackways present are parallel to one another, one of which is a composite formed by at least two individuals walking in single file. Most researchers have focused on the single, clearly discernible G1 trackway while the G2/3 trackway has been largely dismissed due to its composite nature. Here we report the use of a new technique that allows us to decouple the G2 and G3 tracks for the first time. In so doing we are able to quantify the mean footprint topology of the G3 trackway and render it useable for subsequent data analyses. By restoring the effectively 'lost' G3 track, we have doubled the available data on some of the rarest traces directly associated with our Pliocene ancestors. PMID:26902912

  7. Laetoli’s lost tracks: 3D generated mean shape and missing footprints

    PubMed Central

    Bennett, M. R.; Reynolds, S. C.; Morse, S. A.; Budka, M.

    2016-01-01

    The Laetoli site (Tanzania) contains the oldest known hominin footprints, and their interpretation remains open to debate, despite over 35 years of research. The two hominin trackways present are parallel to one another, one of which is a composite formed by at least two individuals walking in single file. Most researchers have focused on the single, clearly discernible G1 trackway while the G2/3 trackway has been largely dismissed due to its composite nature. Here we report the use of a new technique that allows us to decouple the G2 and G3 tracks for the first time. In so doing we are able to quantify the mean footprint topology of the G3 trackway and render it useable for subsequent data analyses. By restoring the effectively ‘lost’ G3 track, we have doubled the available data on some of the rarest traces directly associated with our Pliocene ancestors. PMID:26902912

  8. 3D environment modeling and location tracking using off-the-shelf components

    NASA Astrophysics Data System (ADS)

    Luke, Robert H.

    2016-05-01

    The remarkable popularity of smartphones over the past decade has led to a technological race for dominance in market share. This has resulted in a flood of new processors and sensors that are inexpensive, low power and high performance. These sensors include accelerometers, gyroscope, barometers and most importantly cameras. This sensor suite, coupled with multicore processors, allows a new community of researchers to build small, high performance platforms for low cost. This paper describes a system using off-the-shelf components to perform position tracking as well as environment modeling. The system relies on tracking using stereo vision and inertial navigation to determine movement of the system as well as create a model of the environment sensed by the system.

  9. 3D cloud detection and tracking system for solar forecast using multiple sky imagers

    SciTech Connect

    Peng, Zhenzhou; Yu, Dantong; Huang, Dong; Heiser, John; Yoo, Shinjae; Kalb, Paul

    2015-06-23

    We propose a system for forecasting short-term solar irradiance based on multiple total sky imagers (TSIs). The system utilizes a novel method of identifying and tracking clouds in three-dimensional space and an innovative pipeline for forecasting surface solar irradiance based on the image features of clouds. First, we develop a supervised classifier to detect clouds at the pixel level and output cloud mask. In the next step, we design intelligent algorithms to estimate the block-wise base height and motion of each cloud layer based on images from multiple TSIs. Thus, this information is then applied to stitch images together into larger views, which are then used for solar forecasting. We examine the system’s ability to track clouds under various cloud conditions and investigate different irradiance forecast models at various sites. We confirm that this system can 1) robustly detect clouds and track layers, and 2) extract the significant global and local features for obtaining stable irradiance forecasts with short forecast horizons from the obtained images. Finally, we vet our forecasting system at the 32-megawatt Long Island Solar Farm (LISF). Compared with the persistent model, our system achieves at least a 26% improvement for all irradiance forecasts between one and fifteen minutes.

  10. 3D cloud detection and tracking system for solar forecast using multiple sky imagers

    DOE PAGESBeta

    Peng, Zhenzhou; Yu, Dantong; Huang, Dong; Heiser, John; Yoo, Shinjae; Kalb, Paul

    2015-06-23

    We propose a system for forecasting short-term solar irradiance based on multiple total sky imagers (TSIs). The system utilizes a novel method of identifying and tracking clouds in three-dimensional space and an innovative pipeline for forecasting surface solar irradiance based on the image features of clouds. First, we develop a supervised classifier to detect clouds at the pixel level and output cloud mask. In the next step, we design intelligent algorithms to estimate the block-wise base height and motion of each cloud layer based on images from multiple TSIs. Thus, this information is then applied to stitch images together intomore » larger views, which are then used for solar forecasting. We examine the system’s ability to track clouds under various cloud conditions and investigate different irradiance forecast models at various sites. We confirm that this system can 1) robustly detect clouds and track layers, and 2) extract the significant global and local features for obtaining stable irradiance forecasts with short forecast horizons from the obtained images. Finally, we vet our forecasting system at the 32-megawatt Long Island Solar Farm (LISF). Compared with the persistent model, our system achieves at least a 26% improvement for all irradiance forecasts between one and fifteen minutes.« less

  11. 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.

  12. Pulmonary CT image registration and warping for tracking tissue deformation during the respiratory cycle through 3D consistent image registration

    PubMed Central

    Li, Baojun; Christensen, Gary E.; Hoffman, Eric A.; McLennan, Geoffrey; Reinhardt, Joseph M.

    2008-01-01

    Tracking lung tissues during the respiratory cycle has been a challenging task for diagnostic CT and CT-guided radiotherapy. We propose an intensity- and landmark-based image registration algorithm to perform image registration and warping of 3D pulmonary CT image data sets, based on consistency constraints and matching corresponding airway branchpoints. In this paper, we demonstrate the effectivenss and accuracy of this algorithm in tracking lung tissues by both animal and human data sets. In the animal study, the result showed a tracking accuracy of 1.9 mm between 50% functional residual capacity (FRC) and 85% total lung capacity (TLC) for 12 metal seeds implanted in the lungs of a breathing sheep under precise volume control using a pulmonary ventilator. Visual inspection of the human subject results revealed the algorithm’s potential not only in matching the global shapes, but also in registering the internal structures (e.g., oblique lobe fissures, pulmonary artery branches, etc.). These results suggest that our algorithm has significant potential for warping and tracking lung tissue deformation with applications in diagnostic CT, CT-guided radiotherapy treatment planning, and therapeutic effect evaluation. PMID:19175115

  13. Visualizing and Tracking Evolving Features in 3D Unstructured and Adaptive Datasets

    SciTech Connect

    Silver, D.; Zabusky, N.

    2002-08-01

    The massive amounts of time-varying datasets being generated demand new visualization and quantification techniques. Visualization alone is not sufficient. Without proper measurement information/computations real science cannot be done. Our focus is this work was to combine visualization with quantification of the data to allow for advanced querying and searching. As part of this proposal, we have developed a feature extraction adn tracking methodology which allows researcher to identify features of interest and follow their evolution over time. The implementation is distributed and operates over data In-situ: where it is stored and when it was computed.

  14. The birth of a dinosaur footprint: Subsurface 3D motion reconstruction and discrete element simulation reveal track ontogeny

    PubMed Central

    2014-01-01

    Locomotion over deformable substrates is a common occurrence in nature. Footprints represent sedimentary distortions that provide anatomical, functional, and behavioral insights into trackmaker biology. The interpretation of such evidence can be challenging, however, particularly for fossil tracks recovered at bedding planes below the originally exposed surface. Even in living animals, the complex dynamics that give rise to footprint morphology are obscured by both foot and sediment opacity, which conceals animal–substrate and substrate–substrate interactions. We used X-ray reconstruction of moving morphology (XROMM) to image and animate the hind limb skeleton of a chicken-like bird traversing a dry, granular material. Foot movement differed significantly from walking on solid ground; the longest toe penetrated to a depth of ∼5 cm, reaching an angle of 30° below horizontal before slipping backward on withdrawal. The 3D kinematic data were integrated into a validated substrate simulation using the discrete element method (DEM) to create a quantitative model of limb-induced substrate deformation. Simulation revealed that despite sediment collapse yielding poor quality tracks at the air–substrate interface, subsurface displacements maintain a high level of organization owing to grain–grain support. Splitting the substrate volume along “virtual bedding planes” exposed prints that more closely resembled the foot and could easily be mistaken for shallow tracks. DEM data elucidate how highly localized deformations associated with foot entry and exit generate specific features in the final tracks, a temporal sequence that we term “track ontogeny.” This combination of methodologies fosters a synthesis between the surface/layer-based perspective prevalent in paleontology and the particle/volume-based perspective essential for a mechanistic understanding of sediment redistribution during track formation. PMID:25489092

  15. Lagrangian 3D particle tracking in high-speed flows: Shake-The-Box for multi-pulse systems

    NASA Astrophysics Data System (ADS)

    Novara, Matteo; Schanz, Daniel; Reuther, Nico; Kähler, Christian J.; Schröder, Andreas

    2016-08-01

    The Shake-The-Box (STB) particle tracking technique, recently introduced for time-resolved 3D particle image velocimetry (PIV) images, is applied here to data from a multi-pulse investigation of a turbulent boundary layer flow with adverse pressure gradient in air at 36 m/s ( Re τ = 10,650). The multi-pulse acquisition strategy allows for the recording of four-pulse long time-resolved sequences with a time separation of a few microseconds. The experimental setup consists of a dual-imaging system and a dual-double-cavity laser emitting orthogonal polarization directions to separate the four pulses. The STB particle triangulation and tracking strategy is adapted here to cope with the limited amount of realizations available along the time sequence and to take advantage of the ghost track reduction offered by the use of two independent imaging systems. Furthermore, a correction scheme to compensate for camera vibrations is discussed, together with a method to accurately identify the position of the wall within the measurement domain. Results show that approximately 80,000 tracks can be instantaneously reconstructed within the measurement volume, enabling the evaluation of both dense velocity fields, suitable for spatial gradients evaluation, and highly spatially resolved boundary layer profiles. Turbulent boundary layer profiles obtained from ensemble averaging of the STB tracks are compared to results from 2D-PIV and long-range micro particle tracking velocimetry; the comparison shows the capability of the STB approach in delivering accurate results across a wide range of scales.

  16. 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.

  17. A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks

    SciTech Connect

    Nishimura, K.; Dey, B.; Aston, D.; Leith, D.W.G.S.; Ratcliff, B.; Roberts, D.; Ruckman, L.; Shtol, D.; Varner, G.S.; Va'vra, J.; Vavra, Jerry; /SLAC

    2012-07-30

    We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from {approx}450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of {approx}2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with {approx}1.5 mrad angular resolution and muon energy of E{sub muon} > 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

  18. A Detailed Study of FDIRC Prototype with Waveform Digitizing Electronics in Cosmic Ray Telescope Using 3D Tracks.

    SciTech Connect

    Nishimura, K

    2012-07-01

    We present a detailed study of a novel Cherenkov imaging detector called the Focusing DIRC (FDIRC) with waveform digitizing electronics. In this test study, the FDIRC prototype has been instrumented with seven Hamamatsu H-8500 MaPMTs. Waveforms from ~450 pixels are digitized with waveform sampling electronics based on the BLAB2 ASIC, operating at a sampling speed of ~2.5 GSa/s. The FDIRC prototype was tested in a large cosmic ray telescope (CRT) providing 3D muon tracks with ~1.5 mrad angular resolution and muon energy of Emuon greater than 1.6 GeV. In this study we provide a detailed analysis of the tails in the Cherenkov angle distribution as a function of various variables, compare experimental results with simulation, and identify the major contributions to the tails. We demonstrate that to see the full impact of these tails on the Cherenkov angle resolution, it is crucial to use 3D tracks, and have a full understanding of the role of ambiguities. These issues could not be fully explored in previous FDIRC studies where the beam was perpendicular to the quartz radiator bars. This work is relevant for the final FDIRC prototype of the PID detector at SuperB, which will be tested this year in the CRT setup.

  19. Towards a magnetic localization system for 3-D tracking of tongue movements in speech-language therapy.

    PubMed

    Cheng, Chihwen; Huo, Xueliang; Ghovanloo, Maysam

    2009-01-01

    This paper presents a new magnetic localization system based on a compact triangular sensor setup and three different optimization algorithms, intended for tracking tongue motion in the 3-D oral space. A small permanent magnet, secured on the tongue by tissue adhesives, will be used as a tracer. The magnetic field variations due to tongue motion are detected by a 3-D magneto-inductive sensor array outside the mouth and wirelessly transmitted to a computer. The position and rotation angles of the tracer are reconstructed based on sensor outputs and magnetic dipole equation using DIRECT, Powell, and Nelder-Mead optimization algorithms. Localization accuracy and processing time of the three algorithms are compared using one data set collected in which source-sensor distance was changed from 40 to 150 mm. Powell algorithm showed the best performance with 0.92 mm accuracy in position and 0.7(o) in orientation. The average processing time was 43.9 ms/sample, which can satisfy real time tracking up to approximately 20 Hz. PMID:19964478

  20. A smart homecage system with 3D tracking for long-term behavioral experiments.

    PubMed

    Byunghun Lee; Kiani, Mehdi; Ghovanloo, Maysam

    2014-01-01

    A wirelessly-powered homecage system, called the EnerCage-HC, that is equipped with multi-coil wireless power transfer, closed-loop power control, optical behavioral tracking, and a graphic user interface (GUI) is presented for long-term electrophysiology experiments. The EnerCage-HC system can wirelessly power a mobile unit attached to a small animal subject and also track its behavior in real-time as it is housed inside a standard homecage. The EnerCage-HC system is equipped with one central and four overlapping slanted wire-wound coils (WWCs) with optimal geometries to form 3-and 4-coil power transmission links while operating at 13.56 MHz. Utilizing multi-coil links increases the power transfer efficiency (PTE) compared to conventional 2-coil links and also reduces the number of power amplifiers (PAs) to only one, which significantly reduces the system complexity, cost, and dissipated heat. A Microsoft Kinect installed 90 cm above the homecage localizes the animal position and orientation with 1.6 cm accuracy. An in vivo experiment was conducted on a freely behaving rat by continuously delivering 24 mW to the mobile unit for > 7 hours inside a standard homecage. PMID:25570379

  1. A Smart Homecage System with 3D Tracking for Long-Term Behavioral Experiments

    PubMed Central

    Lee, Byunghun; Kiani, Mehdi; Ghovanloo, Maysam

    2015-01-01

    A wirelessly-powered homecage system, called the EnerCage-HC, that is equipped with multi-coil wireless power transfer, closed-loop power control, optical behavioral tracking, and a graphic user interface (GUI) is presented for long-term electrophysiology experiments. The EnerCage-HC system can wirelessly power a mobile unit attached to a small animal subject and also track its behavior in real-time as it is housed inside a standard homecage. The EnerCage-HC system is equipped with one central and four overlapping slanted wire-wound coils (WWCs) with optimal geometries to form 3- and 4-coil power transmission links while operating at 13.56 MHz. Utilizing multi-coil links increases the power transfer efficiency (PTE) compared to conventional 2-coil links and also reduces the number of power amplifiers (PAs) to only one, which significantly reduces the system complexity, cost, and dissipated heat. A Microsoft Kinect installed 90 cm above the homecage localizes the animal position and orientation with 1.6 cm accuracy. An in vivo experiment was conducted on a freely behaving rat by continuously delivering 24 mW to the mobile unit for > 7 hours inside a standard homecage. PMID:25570379

  2. Multisensor 3D tracking for counter small unmanned air vehicles (CSUAV)

    NASA Astrophysics Data System (ADS)

    Vasquez, Juan R.; Tarplee, Kyle M.; Case, Ellen E.; Zelnio, Anne M.; Rigling, Brian D.

    2008-04-01

    A variety of unmanned air vehicles (UAVs) have been developed for both military and civilian use. The typical large UAV is typically state owned, whereas small UAVs (SUAVs) may be in the form of remote controlled aircraft that are widely available. The potential threat of these SUAVs to both the military and civilian populace has led to research efforts to counter these assets via track, ID, and attack. Difficulties arise from the small size and low radar cross section when attempting to detect and track these targets with a single sensor such as radar or video cameras. In addition, clutter objects make accurate ID difficult without very high resolution data, leading to the use of an acoustic array to support this function. This paper presents a multi-sensor architecture that exploits sensor modes including EO/IR cameras, an acoustic array, and future inclusion of a radar. A sensor resource management concept is presented along with preliminary results from three of the sensors.

  3. Ultra-high-speed 3D astigmatic particle tracking velocimetry: application to particle-laden supersonic impinging jets

    NASA Astrophysics Data System (ADS)

    Buchmann, N. A.; Cierpka, C.; Kähler, C. J.; Soria, J.

    2014-11-01

    The paper demonstrates ultra-high-speed three-component, three-dimensional (3C3D) velocity measurements of micron-sized particles suspended in a supersonic impinging jet flow. Understanding the dynamics of individual particles in such flows is important for the design of particle impactors for drug delivery or cold gas dynamic spray processing. The underexpanded jet flow is produced via a converging nozzle, and micron-sized particles ( d p = 110 μm) are introduced into the gas flow. The supersonic jet impinges onto a flat surface, and the particle impact velocity and particle impact angle are studied for a range of flow conditions and impingement distances. The imaging system consists of an ultra-high-speed digital camera (Shimadzu HPV-1) capable of recording rates of up to 1 Mfps. Astigmatism particle tracking velocimetry (APTV) is used to measure the 3D particle position (Cierpka et al., Meas Sci Technol 21(045401):13, 2010) by coding the particle depth location in the 2D images by adding a cylindrical lens to the high-speed imaging system. Based on the reconstructed 3D particle positions, the particle trajectories are obtained via a higher-order tracking scheme that takes advantage of the high temporal resolution to increase robustness and accuracy of the measurement. It is shown that the particle velocity and impingement angle are affected by the gas flow in a manner depending on the nozzle pressure ratio and stand-off distance where higher pressure ratios and stand-off distances lead to higher impact velocities and larger impact angles.

  4. Aref's chaotic orbits tracked by a general ellipsoid using 3D numerical simulations

    NASA Astrophysics Data System (ADS)

    Shui, Pei; Popinet, Stéphane; Govindarajan, Rama; Valluri, Prashant

    2015-11-01

    The motion of an ellipsoidal solid in an ideal fluid has been shown to be chaotic (Aref, 1993) under the limit of non-integrability of Kirchhoff's equations (Kozlov & Oniscenko, 1982). On the other hand, the particle could stop moving when the damping viscous force is strong enough. We present numerical evidence using our in-house immersed solid solver for 3D chaotic motion of a general ellipsoidal solid and suggest criteria for triggering such motion. Our immersed solid solver functions under the framework of the Gerris flow package of Popinet et al. (2003). This solver, the Gerris Immersed Solid Solver (GISS), resolves 6 degree-of-freedom motion of immersed solids with arbitrary geometry and number. We validate our results against the solution of Kirchhoff's equations. The study also shows that the translational/ rotational energy ratio plays the key role on the motion pattern, while the particle geometry and density ratio between the solid and fluid also have some influence on the chaotic behaviour. Along with several other benchmark cases for viscous flows, we propose prediction of chaotic Aref's orbits as a key benchmark test case for immersed boundary/solid solvers.

  5. Readily Accessible Multiplane Microscopy: 3D Tracking the HIV-1 Genome in Living Cells.

    PubMed

    Itano, Michelle S; Bleck, Marina; Johnson, Daniel S; Simon, Sanford M

    2016-02-01

    Human immunodeficiency virus (HIV)-1 infection and the associated disease AIDS are a major cause of human death worldwide with no vaccine or cure available. The trafficking of HIV-1 RNAs from sites of synthesis in the nucleus, through the cytoplasm, to sites of assembly at the plasma membrane are critical steps in HIV-1 viral replication, but are not well characterized. Here we present a broadly accessible microscopy method that captures multiple focal planes simultaneously, which allows us to image the trafficking of HIV-1 genomic RNAs with high precision. This method utilizes a customization of a commercial multichannel emission splitter that enables high-resolution 3D imaging with single-macromolecule sensitivity. We show with high temporal and spatial resolution that HIV-1 genomic RNAs are most mobile in the cytosol, and undergo confined mobility at sites along the nuclear envelope and in the nucleus and nucleolus. These provide important insights regarding the mechanism by which the HIV-1 RNA genome is transported to the sites of assembly of nascent virions. PMID:26567131

  6. Particle tracking approach for transport in three-dimensional discrete fracture networks: Particle tracking in 3-D DFNs

    SciTech Connect

    Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; Gable, Carl W.; Karra, Satish

    2015-09-16

    The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates mass balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.

  7. Particle tracking approach for transport in three-dimensional discrete fracture networks: Particle tracking in 3-D DFNs

    DOE PAGESBeta

    Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; Gable, Carl W.; Karra, Satish

    2015-09-16

    The discrete fracture network (DFN) model is a method to mimic discrete pathways for fluid flow through a fractured low-permeable rock mass, and may be combined with particle tracking simulations to address solute transport. However, experience has shown that it is challenging to obtain accurate transport results in three-dimensional DFNs because of the high computational burden and difficulty in constructing a high-quality unstructured computational mesh on simulated fractures. We present a new particle tracking capability, which is adapted to control volume (Voronoi polygons) flow solutions on unstructured grids (Delaunay triangulations) on three-dimensional DFNs. The locally mass-conserving finite-volume approach eliminates massmore » balance-related problems during particle tracking. The scalar fluxes calculated for each control volume face by the flow solver are used to reconstruct a Darcy velocity at each control volume centroid. The groundwater velocities can then be continuously interpolated to any point in the domain of interest. The control volumes at fracture intersections are split into four pieces, and the velocity is reconstructed independently on each piece, which results in multiple groundwater velocities at the intersection, one for each fracture on each side of the intersection line. This technique enables detailed particle transport representation through a complex DFN structure. Verified for small DFNs, the new simulation capability enables numerical experiments on advective transport in large DFNs to be performed. As a result, we demonstrate this particle transport approach on a DFN model using parameters similar to those of crystalline rock at a proposed geologic repository for spent nuclear fuel in Forsmark, Sweden.« less

  8. 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

  9. DLP technology application: 3D head tracking and motion correction in medical brain imaging

    NASA Astrophysics Data System (ADS)

    Olesen, Oline V.; Wilm, Jakob; Paulsen, Rasmus R.; Højgaard, Liselotte; Larsen, Rasmus

    2014-03-01

    In this paper we present a novel sensing system, robust Near-infrared Structured Light Scanning (NIRSL) for three-dimensional human model scanning application. Human model scanning due to its nature of various hair and dress appearance and body motion has long been a challenging task. Previous structured light scanning methods typically emitted visible coded light patterns onto static and opaque objects to establish correspondence between a projector and a camera for triangulation. In the success of these methods rely on scanning objects with proper reflective surface for visible light, such as plaster, light colored cloth. Whereas for human model scanning application, conventional methods suffer from low signal to noise ratio caused by low contrast of visible light over the human body. The proposed robust NIRSL, as implemented with the near infrared light, is capable of recovering those dark surfaces, such as hair, dark jeans and black shoes under visible illumination. Moreover, successful structured light scan relies on the assumption that the subject is static during scanning. Due to the nature of body motion, it is very time sensitive to keep this assumption in the case of human model scan. The proposed sensing system, by utilizing the new near-infrared capable high speed LightCrafter DLP projector, is robust to motion, provides accurate and high resolution three-dimensional point cloud, making our system more efficient and robust for human model reconstruction. Experimental results demonstrate that our system is effective and efficient to scan real human models with various dark hair, jeans and shoes, robust to human body motion and produces accurate and high resolution 3D point cloud.

  10. Method for dose-reduced 3D catheter tracking on a scanning-beam digital x-ray system using dynamic electronic collimation

    NASA Astrophysics Data System (ADS)

    Dunkerley, David A. P.; Funk, Tobias; Speidel, Michael A.

    2016-03-01

    Scanning-beam digital x-ray (SBDX) is an inverse geometry x-ray fluoroscopy system capable of tomosynthesis-based 3D catheter tracking. This work proposes a method of dose-reduced 3D tracking using dynamic electronic collimation (DEC) of the SBDX scanning x-ray tube. Positions in the 2D focal spot array are selectively activated to create a regionof- interest (ROI) x-ray field around the tracked catheter. The ROI position is updated for each frame based on a motion vector calculated from the two most recent 3D tracking results. The technique was evaluated with SBDX data acquired as a catheter tip inside a chest phantom was pulled along a 3D trajectory. DEC scans were retrospectively generated from the detector images stored for each focal spot position. DEC imaging of a catheter tip in a volume measuring 11.4 cm across at isocenter required 340 active focal spots per frame, versus 4473 spots in full-FOV mode. The dose-area-product (DAP) and peak skin dose (PSD) for DEC versus full field-of-view (FOV) scanning were calculated using an SBDX Monte Carlo simulation code. DAP was reduced to 7.4% to 8.4% of the full-FOV value, consistent with the relative number of active focal spots (7.6%). For image sequences with a moving catheter, PSD was 33.6% to 34.8% of the full-FOV value. The root-mean-squared-deviation between DEC-based 3D tracking coordinates and full-FOV 3D tracking coordinates was less than 0.1 mm. The 3D distance between the tracked tip and the sheath centerline averaged 0.75 mm. Dynamic electronic collimation can reduce dose with minimal change in tracking performance.

  11. A quantitative study of 3D-scanning frequency and Δd of tracking points on the tooth surface

    PubMed Central

    Li, Hong; Lyu, Peijun; Sun, Yuchun; Wang, Yong; Liang, Xiaoyue

    2015-01-01

    Micro-movement of human jaws in the resting state might influence the accuracy of direct three-dimensional (3D) measurement. Providing a reference for sampling frequency settings of intraoral scanning systems to overcome this influence is important. In this study, we measured micro-movement, or change in distance (∆d), as the change in position of a single tracking point from one sampling time point to another in five human subjects. ∆d of tracking points on incisors at 7 sampling frequencies was judged against the clinical accuracy requirement to select proper sampling frequency settings. The curve equation was then fit quantitatively between ∆d median and the sampling frequency to predict the trend of ∆d with increasing f. The difference of ∆d among the subjects and the difference between upper and lower incisor feature points of the same subject were analyzed by a non-parametric test (α = 0.05). Significant differences of incisor feature points were noted among different subjects and between upper and lower jaws of the same subject (P < 0.01). Overall, ∆d decreased with increasing frequency. When the frequency was 60 Hz, ∆d nearly reached the clinical accuracy requirement. Frequencies higher than 60 Hz did not significantly decrease Δd further. PMID:26400112

  12. Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging.

    PubMed

    Afik, Eldad

    2015-01-01

    Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, fluid dynamics in microfluidic devices, bacteria taxis, cellular trafficking. The 3d position can be determined using 2d imaging alone by measuring the diffraction rings generated by an out-of-focus fluorescent particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from ring occlusion, inclusions and overlaps, and allows resolving particles even when near to each other. It is capable of real time analysis thanks to its high performance and low memory footprint. The proposed algorithm, an offspring of the circle Hough transform, addresses the need to efficiently trace the trajectories of many particles concurrently, when their number in not necessarily fixed, by solving a classification problem, and overcomes the challenges of finding local maxima in the complex parameter space which results from ring clusters and noise. Several algorithmic concepts introduced here can be advantageous in other cases, particularly when dealing with noisy and sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. It is implemented in a microfluidic experiment allowing real-time multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94% and only 1% false-detection. PMID:26329642

  13. Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging

    PubMed Central

    Afik, Eldad

    2015-01-01

    Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, fluid dynamics in microfluidic devices, bacteria taxis, cellular trafficking. The 3d position can be determined using 2d imaging alone by measuring the diffraction rings generated by an out-of-focus fluorescent particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from ring occlusion, inclusions and overlaps, and allows resolving particles even when near to each other. It is capable of real time analysis thanks to its high performance and low memory footprint. The proposed algorithm, an offspring of the circle Hough transform, addresses the need to efficiently trace the trajectories of many particles concurrently, when their number in not necessarily fixed, by solving a classification problem, and overcomes the challenges of finding local maxima in the complex parameter space which results from ring clusters and noise. Several algorithmic concepts introduced here can be advantageous in other cases, particularly when dealing with noisy and sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. It is implemented in a microfluidic experiment allowing real-time multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94% and only 1% false-detection. PMID:26329642

  14. Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging

    NASA Astrophysics Data System (ADS)

    Afik, Eldad

    2015-09-01

    Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, fluid dynamics in microfluidic devices, bacteria taxis, cellular trafficking. The 3d position can be determined using 2d imaging alone by measuring the diffraction rings generated by an out-of-focus fluorescent particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from ring occlusion, inclusions and overlaps, and allows resolving particles even when near to each other. It is capable of real time analysis thanks to its high performance and low memory footprint. The proposed algorithm, an offspring of the circle Hough transform, addresses the need to efficiently trace the trajectories of many particles concurrently, when their number in not necessarily fixed, by solving a classification problem, and overcomes the challenges of finding local maxima in the complex parameter space which results from ring clusters and noise. Several algorithmic concepts introduced here can be advantageous in other cases, particularly when dealing with noisy and sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. It is implemented in a microfluidic experiment allowing real-time multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94% and only 1% false-detection.

  15. Exploring single-molecule interactions through 3D optical trapping and tracking: From thermal noise to protein refolding

    NASA Astrophysics Data System (ADS)

    Wong, Wesley Philip

    The focus of this thesis is the development and application of a novel technique for investigating the structure and dynamics of weak interactions between and within single-molecules. This approach is designed to explore unusual features in bi-directional transitions near equilibrium. The basic idea is to infer molecular events by observing changes in the three-dimensional Brownian fluctuations of a functionalized microsphere held weakly near a reactive substrate. Experimentally, I have developed a unique optical tweezers system that combines an interference technique for accurate 3D tracking (˜1 nm vertically, and ˜2-3 nm laterally) with a continuous autofocus system which stabilizes the trap height to within 1-2 mn over hours. A number of different physical and biological systems were investigated with this instrument. Data interpretation was assisted by a multi-scale Brownian Dynamics simulation that I have developed. I have explored the 3D signatures of different molecular tethers, distinguishing between single and multiple attachments, as well as between stiff and soft linkages. As well, I have developed a technique for measuring the force-dependent compliance of molecular tethers from thermal noise fluctuations and demonstrated this with a short ssDNA oligomer. Another practical approach that I have developed for extracting information from fluctuation measurements is Inverse Brownian Dynamics, which yields the underlying potential of mean force and position dependent diffusion coefficient from the Brownian motion of a particle. I have also developed a new force calibration method that takes into account video motion blur, and that uses this information to measure bead dynamics. Perhaps most significantly, I have trade the first direct observations of the refolding of spectrin repeats under mechanical force, and investigated the force-dependent kinetics of this transition.

  16. Breakup of Finite-Size Colloidal Aggregates in Turbulent Flow Investigated by Three-Dimensional (3D) Particle Tracking Velocimetry.

    PubMed

    Saha, Debashish; Babler, Matthaus U; Holzner, Markus; Soos, Miroslav; Lüthi, Beat; Liberzon, Alex; Kinzelbach, Wolfgang

    2016-01-12

    Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence, where their motion and intermittent breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). The aggregates have an open structure with a fractal dimension of ∼2.2, and their size is 1.4 ± 0.4 mm, which is large, compared to the Kolmogorov length scale (η = 0.15 mm). 3D-PTV of flow tracers allows for the simultaneous measurement of aggregate trajectories and the full velocity gradient tensor along their pathlines, which enables us to access the Lagrangian stress history of individual breakup events. From this data, we found no consistent pattern that relates breakup to the local flow properties at the point of breakup. Also, the correlation between the aggregate size and both shear stress and normal stress at the location of breakage is found to be weaker, when compared with the correlation between size and drag stress. The analysis suggests that the aggregates are mostly broken due to the accumulation of the drag stress over a time lag on the order of the Kolmogorov time scale. This finding is explained by the fact that the aggregates are large, which gives their motion inertia and increases the time for stress propagation inside the aggregate. Furthermore, it is found that the scaling of the largest fragment and the accumulated stress at breakup follows an earlier established power law, i.e., dfrag ∼ σ(-0.6) obtained from laminar nozzle experiments. This indicates that, despite the large size and the different type of hydrodynamic stress, the microscopic mechanism causing breakup is consistent over a wide range of aggregate size and stress magnitude. PMID:26646289

  17. Prospective motion correction of 3D echo-planar imaging data for functional MRI using optical tracking

    PubMed Central

    Todd, Nick; Josephs, Oliver; Callaghan, Martina F.; Lutti, Antoine; Weiskopf, Nikolaus

    2015-01-01

    We evaluated the performance of an optical camera based prospective motion correction (PMC) system in improving the quality of 3D echo-planar imaging functional MRI data. An optical camera and external marker were used to dynamically track the head movement of subjects during fMRI scanning. PMC was performed by using the motion information to dynamically update the sequence's RF excitation and gradient waveforms such that the field-of-view was realigned to match the subject's head movement. Task-free fMRI experiments on five healthy volunteers followed a 2 × 2 × 3 factorial design with the following factors: PMC on or off; 3.0 mm or 1.5 mm isotropic resolution; and no, slow, or fast head movements. Visual and motor fMRI experiments were additionally performed on one of the volunteers at 1.5 mm resolution comparing PMC on vs PMC off for no and slow head movements. Metrics were developed to quantify the amount of motion as it occurred relative to k-space data acquisition. The motion quantification metric collapsed the very rich camera tracking data into one scalar value for each image volume that was strongly predictive of motion-induced artifacts. The PMC system did not introduce extraneous artifacts for the no motion conditions and improved the time series temporal signal-to-noise by 30% to 40% for all combinations of low/high resolution and slow/fast head movement relative to the standard acquisition with no prospective correction. The numbers of activated voxels (p < 0.001, uncorrected) in both task-based experiments were comparable for the no motion cases and increased by 78% and 330%, respectively, for PMC on versus PMC off in the slow motion cases. The PMC system is a robust solution to decrease the motion sensitivity of multi-shot 3D EPI sequences and thereby overcome one of the main roadblocks to their widespread use in fMRI studies. PMID:25783205

  18. Simultaneous tracking of 3D actin and microtubule strains in individual MLO-Y4 osteocytes under oscillatory flow.

    PubMed

    Baik, Andrew D; Qiu, Jun; Hillman, Elizabeth M C; Dong, Cheng; Guo, X Edward

    2013-02-22

    Osteocytes in vivo experience complex fluid shear flow patterns to activate mechanotransduction pathways. The actin and microtubule (MT) cytoskeletons have been shown to play an important role in the osteocyte's biochemical response to fluid shear loading. The dynamic nature of physiologically relevant fluid flow profiles (i.e., 1Hz oscillatory flow) impedes the ability to image and study both actin and MT cytoskeletons simultaneously in the same cell with high spatiotemporal resolution. To overcome these limitations, a multi-channel quasi-3D microscopy technique was developed to track the actin and MT networks simultaneously under steady and oscillatory flow. Cells displayed high intercellular variability and intracellular cytoskeletal variability in strain profiles. Shear Exz was the predominant strain in both steady and oscillatory flows in the form of viscoelastic creep and elastic oscillations, respectively. Dramatic differences were seen in oscillatory flow, however. The actin strains displayed an oscillatory strain profile more often than the MT networks in all the strains tested and had a higher peak-to-trough strain magnitude. Taken together, the actin networks are the more responsive cytoskeletal networks in osteocytes under oscillatory flow and may play a bigger role in mechanotransduction pathway activation and regulation. PMID:23352617

  19. Improvement of the size estimation of 3D tracked droplets using digital in-line holography with joint estimation reconstruction

    NASA Astrophysics Data System (ADS)

    Verrier, N.; Grosjean, N.; Dib, E.; Méès, L.; Fournier, C.; Marié, J.-L.

    2016-04-01

    Digital holography is a valuable tool for three-dimensional information extraction. Among existing configurations, the originally proposed set-up (i.e. Gabor, or in-line holography), is reasonably immune to variations in the experimental environment making it a method of choice for studies of fluid dynamics. Nevertheless, standard hologram reconstruction techniques, based on numerical light back-propagation are prone to artifacts such as twin images or aliases that limit both the quality and quantity of information extracted from the acquired holograms. To get round this issue, the hologram reconstruction as a parametric inverse problem has been shown to accurately estimate 3D positions and the size of seeding particles directly from the hologram. To push the bounds of accuracy on size estimation still further, we propose to fully exploit the information redundancy of a hologram video sequence using joint estimation reconstruction. Applying this approach in a bench-top experiment, we show that it led to a relative precision of 0.13% (for a 60 μm diameter droplet) for droplet size estimation, and a tracking precision of {σx}× {σy}× {σz}=0.15× 0.15× 1~\\text{pixels} .

  20. Cartesian control of redundant robots

    NASA Technical Reports Server (NTRS)

    Colbaugh, R.; Glass, K.

    1989-01-01

    A Cartesian-space position/force controller is presented for redundant robots. The proposed control structure partitions the control problem into a nonredundant position/force trajectory tracking problem and a redundant mapping problem between Cartesian control input F is a set member of the set R(sup m) and robot actuator torque T is a set member of the set R(sup n) (for redundant robots, m is less than n). The underdetermined nature of the F yields T map is exploited so that the robot redundancy is utilized to improve the dynamic response of the robot. This dynamically optimal F yields T map is implemented locally (in time) so that it is computationally efficient for on-line control; however, it is shown that the map possesses globally optimal characteristics. Additionally, it is demonstrated that the dynamically optimal F yields T map can be modified so that the robot redundancy is used to simultaneously improve the dynamic response and realize any specified kinematic performance objective (e.g., manipulability maximization or obstacle avoidance). Computer simulation results are given for a four degree of freedom planar redundant robot under Cartesian control, and demonstrate that position/force trajectory tracking and effective redundancy utilization can be achieved simultaneously with the proposed controller.

  1. Hybrid MV-kV 3D respiratory motion tracking during radiation therapy with low imaging dose

    NASA Astrophysics Data System (ADS)

    Yan, Huagang; Li, Haiyun; Liu, Zhixiang; Nath, Ravinder; Liu, Wu

    2012-12-01

    A novel real-time adaptive MV-kV imaging framework for image-guided radiation therapy is developed to reduce the thoracic and abdominal tumor targeting uncertainty caused by respiration-induced intrafraction motion with ultra-low patient imaging dose. In our method, continuous stereoscopic MV-kV imaging is used at the beginning of a radiation therapy delivery for several seconds to measure the implanted marker positions. After this stereoscopic imaging period, the kV imager is switched off except for the times when no fiducial marker is detected in the cine-MV images. The 3D time-varying marker positions are estimated by combining the MV 2D projection data and the motion correlations between directional components of marker motion established from the stereoscopic imaging period and updated afterwards; in particular, the most likely position is assumed to be the position on the projection line that has the shortest distance to the first principal component line segment constructed from previous trajectory points. An adaptive windowed auto-regressive prediction is utilized to predict the marker position a short time later (310 ms and 460 ms in this study) to allow for tracking system latency. To demonstrate the feasibility and evaluate the accuracy of the proposed method, computer simulations were performed for both arc and fixed-gantry deliveries using 66 h of retrospective tumor motion data from 42 patients treated for thoracic or abdominal cancers. The simulations reveal that using our hybrid approach, a smaller than 1.2 mm or 1.5 mm root-mean-square tracking error can be achieved at a system latency of 310 ms or 460 ms, respectively. Because the kV imaging is only used for a short period of time in our method, extra patient imaging dose can be reduced by an order of magnitude compared to continuous MV-kV imaging, while the clinical tumor targeting accuracy for thoracic or abdominal cancers is maintained. Furthermore, no additional hardware is required with the

  2. Direct measurement of particle size and 3D velocity of a gas-solid pipe flow with digital holographic particle tracking velocimetry.

    PubMed

    Wu, Yingchun; Wu, Xuecheng; Yao, Longchao; Gréhan, Gérard; Cen, Kefa

    2015-03-20

    The 3D measurement of the particles in a gas-solid pipe flow is of great interest, but remains challenging due to curved pipe walls in various engineering applications. Because of the astigmatism induced by the pipe, concentric ellipse fringes in the hologram of spherical particles are observed in the experiments. With a theoretical analysis of the particle holography by an ABCD matrix, the in-focus particle image can be reconstructed by the modified convolution method and fractional Fourier transform. Thereafter, the particle size, 3D position, and velocity are simultaneously measured by digital holographic particle tracking velocimetry (DHPTV). The successful application of DHPTV to the particle size and 3D velocity measurement in a glass pipe's flow can facilitate its 3D diagnostics. PMID:25968543

  3. On the comparison of visual discomfort generated by S3D and 2D content based on eye-tracking features

    NASA Astrophysics Data System (ADS)

    Iatsun, Iana; Larabi, Mohamed-Chaker; Fernandez-Maloigne, Christine

    2014-03-01

    The changing of TV systems from 2D to 3D mode is the next expected step in the telecommunication world. Some works have already been done to perform this progress technically, but interaction of the third dimension with humans is not yet clear. Previously, it was found that any increased load of visual system can create visual fatigue, like prolonged TV watching, computer work or video gaming. But watching S3D can cause another nature of visual fatigue, since all S3D technologies creates illusion of the third dimension based on characteristics of binocular vision. In this work we propose to evaluate and compare the visual fatigue from watching 2D and S3D content. This work shows the difference in accumulation of visual fatigue and its assessment for two types of content. In order to perform this comparison eye-tracking experiments using six commercially available movies were conducted. Healthy naive participants took part into the test and gave their answers feeling the subjective evaluation. It was found that watching stereo 3D content induce stronger feeling of visual fatigue than conventional 2D, and the nature of video has an important effect on its increase. Visual characteristics obtained by using eye-tracking were investigated regarding their relation with visual fatigue.

  4. HSA: integrating multi-track Hi-C data for genome-scale reconstruction of 3D chromatin structure.

    PubMed

    Zou, Chenchen; Zhang, Yuping; Ouyang, Zhengqing

    2016-01-01

    Genome-wide 3C technologies (Hi-C) are being increasingly employed to study three-dimensional (3D) genome conformations. Existing computational approaches are unable to integrate accumulating data to facilitate studying 3D chromatin structure and function. We present HSA ( http://ouyanglab.jax.org/hsa/ ), a flexible tool that jointly analyzes multiple contact maps to infer 3D chromatin structure at the genome scale. HSA globally searches the latent structure underlying different cleavage footprints. Its robustness and accuracy outperform or rival existing tools on extensive simulations and orthogonal experiment validations. Applying HSA to recent in situ Hi-C data, we found the 3D chromatin structures are highly conserved across various human cell types. PMID:26936376

  5. Unstructured grids in 3D and 4D for a time-dependent interface in front tracking with improved accuracy

    SciTech Connect

    Glimm, J.; Grove, J. W.; Li, X. L.; Li, Y.; Xu, Z.

    2002-01-01

    Front tracking traces the dynamic evolution of an interface separating differnt materials or fluid components. In this paper, they describe three types of the grid generation methods used in the front tracking method. One is the unstructured surface grid. The second is a structured grid-based reconstruction method. The third is a time-space grid, also grid based, for a conservative tracking algorithm with improved accuracy.

  6. Validation of 3D motion tracking of pulmonary lesions using CT fluoroscopy images for robotically assisted lung biopsy

    NASA Astrophysics Data System (ADS)

    Xu, Sheng; Fichtinger, Gabor; Taylor, Russell H.; Cleary, Kevin R.

    2005-04-01

    As recently proposed in our previous work, the two-dimensional CT fluoroscopy image series can be used to track the three-dimensional motion of a pulmonary lesion. The assumption is that the lung tissue is locally rigid, so that the real-time CT fluoroscopy image can be combined with a preoperative CT volume to infer the position of the lesion when the lesion is not in the CT fluoroscopy imaging plane. In this paper, we validate the basic properties of our tracking algorithm using a synthetic four-dimensional lung dataset. The motion tracking result is compared to the ground truth of the four-dimensional dataset. The optimal parameter configurations of the algorithm are discussed. The robustness and accuracy of the tracking algorithm are presented. The error analysis shows that the local rigidity error is the principle component of the tracking error. The error increases as the lesion moves away from the image region being registered. Using the synthetic four-dimensional lung data, the average tracking error over a complete respiratory cycle is 0.8 mm for target lesions inside the lung. As a result, the motion tracking algorithm can potentially alleviate the effect of respiratory motion in CT fluoroscopy-guided lung biopsy.

  7. Accuracy and precision of a custom camera-based system for 2-d and 3-d motion tracking during speech and nonspeech motor tasks.

    PubMed

    Feng, Yongqiang; Max, Ludo

    2014-04-01

    PURPOSE Studying normal or disordered motor control requires accurate motion tracking of the effectors (e.g., orofacial structures). The cost of electromagnetic, optoelectronic, and ultrasound systems is prohibitive for many laboratories and limits clinical applications. For external movements (lips, jaw), video-based systems may be a viable alternative, provided that they offer high temporal resolution and submillimeter accuracy. METHOD The authors examined the accuracy and precision of 2-D and 3-D data recorded with a system that combines consumer-grade digital cameras capturing 60, 120, or 240 frames per second (fps), retro-reflective markers, commercially available computer software (APAS, Ariel Dynamics), and a custom calibration device. RESULTS Overall root-mean-square error (RMSE) across tests was 0.15 mm for static tracking and 0.26 mm for dynamic tracking, with corresponding precision (SD) values of 0.11 and 0.19 mm, respectively. The effect of frame rate varied across conditions, but, generally, accuracy was reduced at 240 fps. The effect of marker size (3- vs. 6-mm diameter) was negligible at all frame rates for both 2-D and 3-D data. CONCLUSION Motion tracking with consumer-grade digital cameras and the APAS software can achieve submillimeter accuracy at frame rates that are appropriate for kinematic analyses of lip/jaw movements for both research and clinical purposes. PMID:24686484

  8. Accuracy and precision of a custom camera-based system for 2D and 3D motion tracking during speech and nonspeech motor tasks

    PubMed Central

    Feng, Yongqiang; Max, Ludo

    2014-01-01

    Purpose Studying normal or disordered motor control requires accurate motion tracking of the effectors (e.g., orofacial structures). The cost of electromagnetic, optoelectronic, and ultrasound systems is prohibitive for many laboratories, and limits clinical applications. For external movements (lips, jaw), video-based systems may be a viable alternative, provided that they offer high temporal resolution and sub-millimeter accuracy. Method We examined the accuracy and precision of 2D and 3D data recorded with a system that combines consumer-grade digital cameras capturing 60, 120, or 240 frames per second (fps), retro-reflective markers, commercially-available computer software (APAS, Ariel Dynamics), and a custom calibration device. Results Overall mean error (RMSE) across tests was 0.15 mm for static tracking and 0.26 mm for dynamic tracking, with corresponding precision (SD) values of 0.11 and 0.19 mm, respectively. The effect of frame rate varied across conditions, but, generally, accuracy was reduced at 240 fps. The effect of marker size (3 vs. 6 mm diameter) was negligible at all frame rates for both 2D and 3D data. Conclusion Motion tracking with consumer-grade digital cameras and the APAS software can achieve sub-millimeter accuracy at frame rates that are appropriate for kinematic analyses of lip/jaw movements for both research and clinical purposes. PMID:24686484

  9. Position tracking of moving liver lesion based on real-time registration between 2D ultrasound and 3D preoperative images

    SciTech Connect

    Weon, Chijun; Hyun Nam, Woo; Lee, Duhgoon; Ra, Jong Beom; Lee, Jae Young

    2015-01-15

    Purpose: Registration between 2D ultrasound (US) and 3D preoperative magnetic resonance (MR) (or computed tomography, CT) images has been studied recently for US-guided intervention. However, the existing techniques have some limits, either in the registration speed or the performance. The purpose of this work is to develop a real-time and fully automatic registration system between two intermodal images of the liver, and subsequently an indirect lesion positioning/tracking algorithm based on the registration result, for image-guided interventions. Methods: The proposed position tracking system consists of three stages. In the preoperative stage, the authors acquire several 3D preoperative MR (or CT) images at different respiratory phases. Based on the transformations obtained from nonrigid registration of the acquired 3D images, they then generate a 4D preoperative image along the respiratory phase. In the intraoperative preparatory stage, they properly attach a 3D US transducer to the patient’s body and fix its pose using a holding mechanism. They then acquire a couple of respiratory-controlled 3D US images. Via the rigid registration of these US images to the 3D preoperative images in the 4D image, the pose information of the fixed-pose 3D US transducer is determined with respect to the preoperative image coordinates. As feature(s) to use for the rigid registration, they may choose either internal liver vessels or the inferior vena cava. Since the latter is especially useful in patients with a diffuse liver disease, the authors newly propose using it. In the intraoperative real-time stage, they acquire 2D US images in real-time from the fixed-pose transducer. For each US image, they select candidates for its corresponding 2D preoperative slice from the 4D preoperative MR (or CT) image, based on the predetermined pose information of the transducer. The correct corresponding image is then found among those candidates via real-time 2D registration based on a

  10. Creation of 3D digital anthropomorphic phantoms which model actual patient non-rigid body motion as determined from MRI and position tracking studies of volunteers

    NASA Astrophysics Data System (ADS)

    Connolly, C. M.; Konik, A.; Dasari, P. K. R.; Segars, P.; Zheng, S.; Johnson, K. L.; Dey, J.; King, M. A.

    2011-03-01

    Patient motion can cause artifacts, which can lead to difficulty in interpretation. The purpose of this study is to create 3D digital anthropomorphic phantoms which model the location of the structures of the chest and upper abdomen of human volunteers undergoing a series of clinically relevant motions. The 3D anatomy is modeled using the XCAT phantom and based on MRI studies. The NURBS surfaces of the XCAT are interactively adapted to fit the MRI studies. A detailed XCAT phantom is first developed from an EKG triggered Navigator acquisition composed of sagittal slices with a 3 x 3 x 3 mm voxel dimension. Rigid body motion states are then acquired at breath-hold as sagittal slices partially covering the thorax, centered on the heart, with 9 mm gaps between them. For non-rigid body motion requiring greater sampling, modified Navigator sequences covering the entire thorax with 3 mm gaps between slices are obtained. The structures of the initial XCAT are then adapted to fit these different motion states. Simultaneous to MRI imaging the positions of multiple reflective markers on stretchy bands about the volunteer's chest and abdomen are optically tracked in 3D via stereo imaging. These phantoms with combined position tracking will be used to investigate both imaging-data-driven and motion-tracking strategies to estimate and correct for patient motion. Our initial application will be to cardiacperfusion SPECT imaging where the XCAT phantoms will be used to create patient activity and attenuation distributions for each volunteer with corresponding motion tracking data from the markers on the body-surface. Monte Carlo methods will then be used to simulate SPECT acquisitions, which will be used to evaluate various motion estimation and correction strategies.

  11. Experimental evaluations of the accuracy of 3D and 4D planning in robotic tracking stereotactic body radiotherapy for lung cancers

    SciTech Connect

    Chan, Mark K. H.; Kwong, Dora L. W.; Ng, Sherry C. Y.; Tong, Anthony S. M.; Tam, Eric K. W.

    2013-04-15

    Purpose: Due to the complexity of 4D target tracking radiotherapy, the accuracy of this treatment strategy should be experimentally validated against established standard 3D technique. This work compared the accuracy of 3D and 4D dose calculations in respiration tracking stereotactic body radiotherapy (SBRT). Methods: Using the 4D planning module of the CyberKnife treatment planning system, treatment plans for a moving target and a static off-target cord structure were created on different four-dimensional computed tomography (4D-CT) datasets of a thorax phantom moving in different ranges. The 4D planning system used B-splines deformable image registrations (DIR) to accumulate dose distributions calculated on different breathing geometries, each corresponding to a static 3D-CT image of the 4D-CT dataset, onto a reference image to compose a 4D dose distribution. For each motion, 4D optimization was performed to generate a 4D treatment plan of the moving target. For comparison with standard 3D planning, each 4D plan was copied to the reference end-exhale images and a standard 3D dose calculation was followed. Treatment plans of the off-target structure were first obtained by standard 3D optimization on the end-exhale images. Subsequently, they were applied to recalculate the 4D dose distributions using DIRs. All dose distributions that were initially obtained using the ray-tracing algorithm with equivalent path-length heterogeneity correction (3D{sub EPL} and 4D{sub EPL}) were recalculated by a Monte Carlo algorithm (3D{sub MC} and 4D{sub MC}) to further investigate the effects of dose calculation algorithms. The calculated 3D{sub EPL}, 3D{sub MC}, 4D{sub EPL}, and 4D{sub MC} dose distributions were compared to measurements by Gafchromic EBT2 films in the axial and coronal planes of the moving target object, and the coronal plane for the static off-target object based on the {gamma} metric at 5%/3mm criteria ({gamma}{sub 5%/3mm}). Treatment plans were considered

  12. Using virtual reality technology and hand tracking technology to create software for training surgical skills in 3D game

    NASA Astrophysics Data System (ADS)

    Zakirova, A. A.; Ganiev, B. A.; Mullin, R. I.

    2015-11-01

    The lack of visible and approachable ways of training surgical skills is one of the main problems in medical education. Existing simulation training devices are not designed to teach students, and are not available due to the high cost of the equipment. Using modern technologies such as virtual reality and hands movements fixation technology we want to create innovative method of learning the technics of conducting operations in 3D game format, which can make education process interesting and effective. Creating of 3D format virtual simulator will allow to solve several conceptual problems at once: opportunity of practical skills improvement unlimited by the time without the risk for patient, high realism of environment in operational and anatomic body structures, using of game mechanics for information perception relief and memorization of methods acceleration, accessibility of this program.

  13. Longitudinal, label-free, quantitative tracking of cell death and viability in a 3D tumor model with OCT

    NASA Astrophysics Data System (ADS)

    Jung, Yookyung; Klein, Oliver J.; Wang, Hequn; Evans, Conor L.

    2016-06-01

    Three-dimensional in vitro tumor models are highly useful tools for studying tumor growth and treatment response of malignancies such as ovarian cancer. Existing viability and treatment assessment assays, however, face shortcomings when applied to these large, complex, and heterogeneous culture systems. Optical coherence tomography (OCT) is a noninvasive, label-free, optical imaging technique that can visualize live cells and tissues over time with subcellular resolution and millimeters of optical penetration depth. Here, we show that OCT is capable of carrying out high-content, longitudinal assays of 3D culture treatment response. We demonstrate the usage and capability of OCT for the dynamic monitoring of individual and combination therapeutic regimens in vitro, including both chemotherapy drugs and photodynamic therapy (PDT) for ovarian cancer. OCT was validated against the standard LIVE/DEAD Viability/Cytotoxicity Assay in small tumor spheroid cultures, showing excellent correlation with existing standards. Importantly, OCT was shown to be capable of evaluating 3D spheroid treatment response even when traditional viability assays failed. OCT 3D viability imaging revealed synergy between PDT and the standard-of-care chemotherapeutic carboplatin that evolved over time. We believe the efficacy and accuracy of OCT in vitro drug screening will greatly contribute to the field of cancer treatment and therapy evaluation.

  14. Longitudinal, label-free, quantitative tracking of cell death and viability in a 3D tumor model with OCT.

    PubMed

    Jung, Yookyung; Klein, Oliver J; Wang, Hequn; Evans, Conor L

    2016-01-01

    Three-dimensional in vitro tumor models are highly useful tools for studying tumor growth and treatment response of malignancies such as ovarian cancer. Existing viability and treatment assessment assays, however, face shortcomings when applied to these large, complex, and heterogeneous culture systems. Optical coherence tomography (OCT) is a noninvasive, label-free, optical imaging technique that can visualize live cells and tissues over time with subcellular resolution and millimeters of optical penetration depth. Here, we show that OCT is capable of carrying out high-content, longitudinal assays of 3D culture treatment response. We demonstrate the usage and capability of OCT for the dynamic monitoring of individual and combination therapeutic regimens in vitro, including both chemotherapy drugs and photodynamic therapy (PDT) for ovarian cancer. OCT was validated against the standard LIVE/DEAD Viability/Cytotoxicity Assay in small tumor spheroid cultures, showing excellent correlation with existing standards. Importantly, OCT was shown to be capable of evaluating 3D spheroid treatment response even when traditional viability assays failed. OCT 3D viability imaging revealed synergy between PDT and the standard-of-care chemotherapeutic carboplatin that evolved over time. We believe the efficacy and accuracy of OCT in vitro drug screening will greatly contribute to the field of cancer treatment and therapy evaluation. PMID:27248849

  15. Longitudinal, label-free, quantitative tracking of cell death and viability in a 3D tumor model with OCT

    PubMed Central

    Jung, Yookyung; Klein, Oliver J.; Wang, Hequn; Evans, Conor L.

    2016-01-01

    Three-dimensional in vitro tumor models are highly useful tools for studying tumor growth and treatment response of malignancies such as ovarian cancer. Existing viability and treatment assessment assays, however, face shortcomings when applied to these large, complex, and heterogeneous culture systems. Optical coherence tomography (OCT) is a noninvasive, label-free, optical imaging technique that can visualize live cells and tissues over time with subcellular resolution and millimeters of optical penetration depth. Here, we show that OCT is capable of carrying out high-content, longitudinal assays of 3D culture treatment response. We demonstrate the usage and capability of OCT for the dynamic monitoring of individual and combination therapeutic regimens in vitro, including both chemotherapy drugs and photodynamic therapy (PDT) for ovarian cancer. OCT was validated against the standard LIVE/DEAD Viability/Cytotoxicity Assay in small tumor spheroid cultures, showing excellent correlation with existing standards. Importantly, OCT was shown to be capable of evaluating 3D spheroid treatment response even when traditional viability assays failed. OCT 3D viability imaging revealed synergy between PDT and the standard-of-care chemotherapeutic carboplatin that evolved over time. We believe the efficacy and accuracy of OCT in vitro drug screening will greatly contribute to the field of cancer treatment and therapy evaluation. PMID:27248849

  16. Use of MV and kV imager correlation for maintaining continuous real-time 3D internal marker tracking during beam interruptions

    NASA Astrophysics Data System (ADS)

    Wiersma, R. D.; Riaz, N.; Dieterich, Sonja; Suh, Yelin; Xing, L.

    2009-01-01

    The integration of onboard kV imaging together with a MV electronic portal imaging device (EPID) on linear accelerators (LINAC) can provide an easy to implement real-time 3D organ position monitoring solution for treatment delivery. Currently, real-time MV-kV tracking has only been demonstrated by simultaneous imagining by both MV and kV imaging devices. However, modalities such as step-and-shoot IMRT (SS-IMRT), which inherently contain MV beam interruptions, can lead to loss of target information necessary for 3D localization. Additionally, continuous kV imaging throughout the treatment delivery can lead to high levels of imaging dose to the patient. This work demonstrates for the first time how full 3D target tracking can be maintained even in the presence of such beam interruption, or MV/kV beam interleave, by use of a relatively simple correlation model together with MV-kV tracking. A moving correlation model was constructed using both present and prior positions of the marker in the available MV or kV image to compute the position of the marker on the interrupted imager. A commercially available radiotherapy system, equipped with both MV and kV imaging devices, was used to deliver typical SS-IMRT lung treatment plans to a 4D phantom containing internally embedded metallic markers. To simulate actual lung tumor motion, previous recorded 4D lung patient motion data were used. Lung tumor motion data of five separate patients were inputted into the 4D phantom, and typical SS-IMRT lung plans were delivered to simulate actual clinical deliveries. Application of the correlation model to SS-IMRT lung treatment deliveries was found to be an effective solution for maintaining continuous 3D tracking during 'step' beam interruptions. For deliveries involving five or more gantry angles with 50 or more fields per plan, the positional errors were found to have <=1 mm root mean squared error (RMSE) in all three spatial directions. In addition to increasing the robustness of

  17. Performance and suitability assessment of a real-time 3D electromagnetic needle tracking system for interstitial brachytherapy

    PubMed Central

    Boutaleb, Samir; Fillion, Olivier; Bonillas, Antonio; Hautvast, Gilion; Binnekamp, Dirk; Beaulieu, Luc

    2015-01-01

    Purpose Accurate insertion and overall needle positioning are key requirements for effective brachytherapy treatments. This work aims at demonstrating the accuracy performance and the suitability of the Aurora® V1 Planar Field Generator (PFG) electromagnetic tracking system (EMTS) for real-time treatment assistance in interstitial brachytherapy procedures. Material and methods The system's performance was characterized in two distinct studies. First, in an environment free of EM disturbance, the boundaries of the detection volume of the EMTS were characterized and a tracking error analysis was performed. Secondly, a distortion analysis was conducted as a means of assessing the tracking accuracy performance of the system in the presence of potential EM disturbance generated by the proximity of standard brachytherapy components. Results The tracking accuracy experiments showed that positional errors were typically 2 ± 1 mm in a zone restricted to the first 30 cm of the detection volume. However, at the edges of the detection volume, sensor position errors of up to 16 mm were recorded. On the other hand, orientation errors remained low at ± 2° for most of the measurements. The EM distortion analysis showed that the presence of typical brachytherapy components in vicinity of the EMTS had little influence on tracking accuracy. Position errors of less than 1 mm were recorded with all components except with a metallic arm support, which induced a mean absolute error of approximately 1.4 mm when located 10 cm away from the needle sensor. Conclusions The Aurora® V1 PFG EMTS possesses a great potential for real-time treatment assistance in general interstitial brachytherapy. In view of our experimental results, we however recommend that the needle axis remains as parallel as possible to the generator surface during treatment and that the tracking zone be restricted to the first 30 cm from the generator surface. PMID:26622231

  18. Tracking time interval changes of pulmonary nodules on follow-up 3D CT images via image-based risk score of lung cancer

    NASA Astrophysics Data System (ADS)

    Kawata, Y.; Niki, N.; Ohmatsu, H.; Kusumoto, M.; Tsuchida, T.; Eguchi, K.; Kaneko, M.; Moriyama, N.

    2013-03-01

    In this paper, we present a computer-aided follow-up (CAF) scheme to support physicians to track interval changes of pulmonary nodules on three dimensional (3D) CT images and to decide the treatment strategies without making any under or over treatment. Our scheme involves analyzing CT histograms to evaluate the volumetric distribution of CT values within pulmonary nodules. A variational Bayesian mixture modeling framework translates the image-derived features into an image-based risk score for predicting the patient recurrence-free survival. Through applying our scheme to follow-up 3D CT images of pulmonary nodules, we demonstrate the potential usefulness of the CAF scheme which can provide the trajectories that can characterize time interval changes of pulmonary nodules.

  19. Tracking naturally occurring indoor features in 2-D and 3-D with lidar range/amplitude data

    SciTech Connect

    Adams, M.D.; Kerstens, A.

    1998-09-01

    Sensor-data processing for the interpretation of a mobile robot`s indoor environment, and the manipulation of this data for reliable localization, are still some of the most important issues in robotics. This article presents algorithms that determine the true position of a mobile robot, based on real 2-D and 3-D optical range and intensity data. The authors start with the physics of the particular type of sensor used, so that the extraction of reliable and repeatable information (namely, edge coordinates) can be determined, taking into account the noise associated with each range sample and the possibility of optical multiple-path effects. Again, applying the physical model of the sensor, the estimated positions of the mobile robot and the uncertainty in these positions are determined. They demonstrate real experiments using 2-D and 3-D scan data taken in indoor environments. To update the robot`s position reliably, the authors address the problem of matching the information recorded in a scan to, first, an a priori map, and second, to information recorded in previous scans, eliminating the need for an a priori map.

  20. Applications of 3D hydrodynamic and particle tracking models in the San Francisco bay-delta estuary

    USGS Publications Warehouse

    Smith, P.E.; Donovan, J.M.; Wong, H.F.N.

    2005-01-01

    Three applications of three-dimensional hydrodynamic and particle-tracking models are currently underway by the United States Geological Survey in the San Francisco Bay-Delta Estuary. The first application is to the San Francisco Bay and a portion of the coastal ocean. The second application is to an important, gated control channel called the Delta Cross Channel, located within the northern portion of the Sacramento-San Joaquin River Delta. The third application is to a reach of the San Joaquin River near Stockton, California where a significant dissolved oxygen problem exists due, in part, to conditions associated with the deep-water ship channel for the Port of Stockton, California. This paper briefly discusses the hydrodynamic and particle tracking models being used and the three applications. Copyright ASCE 2005.

  1. A Cartesian scheme for compressible multimaterial models in 3D

    NASA Astrophysics Data System (ADS)

    de Brauer, Alexia; Iollo, Angelo; Milcent, Thomas

    2016-05-01

    We model the three-dimensional interaction of compressible materials separated by sharp interfaces. We simulate fluid and hyperelastic solid flows in a fully Eulerian framework. The scheme is the same for all materials and can handle large deformations and frictionless contacts. Necessary conditions for hyperbolicity of the hyperelastic neohookean model in three dimensions are proved thanks to an explicit computation of the characteristic speeds. We present stiff multimaterial interactions including air-helium and water-air shock interactions, projectile-shield impacts in air and rebounds.

  2. 3D tracking of single nanoparticles and quantum dots in living cells by out-of-focus imaging with diffraction pattern recognition

    NASA Astrophysics Data System (ADS)

    Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S.

    2015-11-01

    Live cells are three-dimensional environments where biological molecules move to find their targets and accomplish their functions. However, up to now, most single molecule investigations have been limited to bi-dimensional studies owing to the complexity of 3d-tracking techniques. Here, we present a novel method for three-dimensional localization of single nano-emitters based on automatic recognition of out-of-focus diffraction patterns. Our technique can be applied to track the movements of single molecules in living cells using a conventional epifluorescence microscope. We first demonstrate three-dimensional localization of fluorescent nanobeads over 4 microns depth with accuracy below 2 nm in vitro. Remarkably, we also establish three-dimensional tracking of Quantum Dots, overcoming their anisotropic emission, by adopting a ligation strategy that allows rotational freedom of the emitter combined with proper pattern recognition. We localize commercially available Quantum Dots in living cells with accuracy better than 7 nm over 2 microns depth. We validate our technique by tracking the three-dimensional movements of single protein-conjugated Quantum Dots in living cell. Moreover, we find that important localization errors can occur in off-focus imaging when improperly calibrated and we give indications to avoid them. Finally, we share a Matlab script that allows readily application of our technique by other laboratories.

  3. 3D tracking of single nanoparticles and quantum dots in living cells by out-of-focus imaging with diffraction pattern recognition

    PubMed Central

    Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S.

    2015-01-01

    Live cells are three-dimensional environments where biological molecules move to find their targets and accomplish their functions. However, up to now, most single molecule investigations have been limited to bi-dimensional studies owing to the complexity of 3d-tracking techniques. Here, we present a novel method for three-dimensional localization of single nano-emitters based on automatic recognition of out-of-focus diffraction patterns. Our technique can be applied to track the movements of single molecules in living cells using a conventional epifluorescence microscope. We first demonstrate three-dimensional localization of fluorescent nanobeads over 4 microns depth with accuracy below 2 nm in vitro. Remarkably, we also establish three-dimensional tracking of Quantum Dots, overcoming their anisotropic emission, by adopting a ligation strategy that allows rotational freedom of the emitter combined with proper pattern recognition. We localize commercially available Quantum Dots in living cells with accuracy better than 7 nm over 2 microns depth. We validate our technique by tracking the three-dimensional movements of single protein-conjugated Quantum Dots in living cell. Moreover, we find that important localization errors can occur in off-focus imaging when improperly calibrated and we give indications to avoid them. Finally, we share a Matlab script that allows readily application of our technique by other laboratories. PMID:26526410

  4. 3D tracking of single nanoparticles and quantum dots in living cells by out-of-focus imaging with diffraction pattern recognition.

    PubMed

    Gardini, Lucia; Capitanio, Marco; Pavone, Francesco S

    2015-01-01

    Live cells are three-dimensional environments where biological molecules move to find their targets and accomplish their functions. However, up to now, most single molecule investigations have been limited to bi-dimensional studies owing to the complexity of 3d-tracking techniques. Here, we present a novel method for three-dimensional localization of single nano-emitters based on automatic recognition of out-of-focus diffraction patterns. Our technique can be applied to track the movements of single molecules in living cells using a conventional epifluorescence microscope. We first demonstrate three-dimensional localization of fluorescent nanobeads over 4 microns depth with accuracy below 2 nm in vitro. Remarkably, we also establish three-dimensional tracking of Quantum Dots, overcoming their anisotropic emission, by adopting a ligation strategy that allows rotational freedom of the emitter combined with proper pattern recognition. We localize commercially available Quantum Dots in living cells with accuracy better than 7 nm over 2 microns depth. We validate our technique by tracking the three-dimensional movements of single protein-conjugated Quantum Dots in living cell. Moreover, we find that important localization errors can occur in off-focus imaging when improperly calibrated and we give indications to avoid them. Finally, we share a Matlab script that allows readily application of our technique by other laboratories. PMID:26526410

  5. Live imaging and quantitative analysis of gastrulation in mouse embryos using light-sheet microscopy and 3D tracking tools.

    PubMed

    Ichikawa, Takehiko; Nakazato, Kenichi; Keller, Philipp J; Kajiura-Kobayashi, Hiroko; Stelzer, Ernst H K; Mochizuki, Atsushi; Nonaka, Shigenori

    2014-03-01

    This protocol describes how to observe gastrulation in living mouse embryos by using light-sheet microscopy and computational tools to analyze the resulting image data at the single-cell level. We describe a series of techniques needed to image the embryos under physiological conditions, including how to hold mouse embryos without agarose embedding, how to transfer embryos without air exposure and how to construct environmental chambers for live imaging by digital scanned light-sheet microscopy (DSLM). Computational tools include manual and semiautomatic tracking programs that are developed for analyzing the large 4D data sets acquired with this system. Note that this protocol does not include details of how to build the light-sheet microscope itself. Time-lapse imaging ends within 12 h, with subsequent tracking analysis requiring 3-6 d. Other than some mouse-handling skills, this protocol requires no advanced skills or knowledge. Light-sheet microscopes are becoming more widely available, and thus the techniques outlined in this paper should be helpful for investigating mouse embryogenesis. PMID:24525751

  6. Terrestrial laser scanning point clouds time series for the monitoring of slope movements: displacement measurement using image correlation and 3D feature tracking

    NASA Astrophysics Data System (ADS)

    Bornemann, Pierrick; Jean-Philippe, Malet; André, Stumpf; Anne, Puissant; Julien, Travelletti

    2016-04-01

    Dense multi-temporal point clouds acquired with terrestrial laser scanning (TLS) have proved useful for the study of structure and kinematics of slope movements. Most of the existing deformation analysis methods rely on the use of interpolated data. Approaches that use multiscale image correlation provide a precise and robust estimation of the observed movements; however, for non-rigid motion patterns, these methods tend to underestimate all the components of the movement. Further, for rugged surface topography, interpolated data introduce a bias and a loss of information in some local places where the point cloud information is not sufficiently dense. Those limits can be overcome by using deformation analysis exploiting directly the original 3D point clouds assuming some hypotheses on the deformation (e.g. the classic ICP algorithm requires an initial guess by the user of the expected displacement patterns). The objective of this work is therefore to propose a deformation analysis method applied to a series of 20 3D point clouds covering the period October 2007 - October 2015 at the Super-Sauze landslide (South East French Alps). The dense point clouds have been acquired with a terrestrial long-range Optech ILRIS-3D laser scanning device from the same base station. The time series are analyzed using two approaches: 1) a method of correlation of gradient images, and 2) a method of feature tracking in the raw 3D point clouds. The estimated surface displacements are then compared with GNSS surveys on reference targets. Preliminary results tend to show that the image correlation method provides a good estimation of the displacement fields at first order, but shows limitations such as the inability to track some deformation patterns, and the use of a perspective projection that does not maintain original angles and distances in the correlated images. Results obtained with 3D point clouds comparison algorithms (C2C, ICP, M3C2) bring additional information on the

  7. Development of the 3-D Track Imager for Medium and High-Energy Gamma-Ray Telescopes

    NASA Technical Reports Server (NTRS)

    Hunter, Stanley D.

    2006-01-01

    The Advanced Compton Telescope (ACT) and Advanced Pair Telescope (APT) are envisioned as the next medium (0.3 ^ 50 MeV) and high-energy (30 MeV - greater than 100 GeV) gamma-ray missions. These missions will address many research focus areas of the Structure and Evolution of the Universe Roadmap. These areas include: element formation, matter, energy, & magnetic field interactions in galaxies, AGN & GRB emission, and behavior of matter in extreme environments of black holes & pulsars. Achieving these science goals requires a substantial increases in telescope sensitivity and angular resolution. This talk will discuss how these goals can be met with the three-dimensional track imager (3-DTI), a large volume, low density, time projection chamber with two-dimensional micro-well detector readout and report on our development of a 10 cm x 10 cm x 30 prototype instrument.

  8. 3D-localization microscopy and tracking of FoF1-ATP synthases in living bacteria

    NASA Astrophysics Data System (ADS)

    Renz, Anja; Renz, Marc; Klütsch, Diana; Deckers-Hebestreit, Gabriele; Börsch, Michael

    2015-03-01

    FoF1-ATP synthases are membrane-embedded protein machines that catalyze the synthesis of adenosine triphosphate. Using photoactivation-based localization microscopy (PALM) in TIR-illumination as well as structured illumination microscopy (SIM), we explore the spatial distribution and track single FoF1-ATP synthases in living E. coli cells under physiological conditions at different temperatures. For quantitative diffusion analysis by mean-squared-displacement measurements, the limited size of the observation area in the membrane with its significant membrane curvature has to be considered. Therefore, we applied a 'sliding observation window' approach (M. Renz et al., Proc. SPIE 8225, 2012) and obtained the one-dimensional diffusion coefficient of FoF1-ATP synthase diffusing on the long axis in living E. coli cells.

  9. Improved image guidance technique for minimally invasive mitral valve repair using real-time tracked 3D ultrasound

    NASA Astrophysics Data System (ADS)

    Rankin, Adam; Moore, John; Bainbridge, Daniel; Peters, Terry

    2016-03-01

    In the past ten years, numerous new surgical and interventional techniques have been developed for treating heart valve disease without the need for cardiopulmonary bypass. Heart valve repair is now being performed in a blood-filled environment, reinforcing the need for accurate and intuitive imaging techniques. Previous work has demonstrated how augmenting ultrasound with virtual representations of specific anatomical landmarks can greatly simplify interventional navigation challenges and increase patient safety. These techniques often complicate interventions by requiring additional steps taken to manually define and initialize virtual models. Furthermore, overlaying virtual elements into real-time image data can also obstruct the view of salient image information. To address these limitations, a system was developed that uses real-time volumetric ultrasound alongside magnetically tracked tools presented in an augmented virtuality environment to provide a streamlined navigation guidance platform. In phantom studies simulating a beating-heart navigation task, procedure duration and tool path metrics have achieved comparable performance to previous work in augmented virtuality techniques, and considerable improvement over standard of care ultrasound guidance.

  10. Splitting the Cartesian point

    SciTech Connect

    Blodwell, J.F.

    1987-10-01

    It is argued that the point structure of space and time must be constructed from the primitive extensional character of space and time. A procedure for doing this is laid down and applied to one-dimensional and two-dimensional systems of abstract extensions. Topological and metrical properties of the constructed point systems, which differ nontrivially from the usual R and R/sup 2/ models, are examined. Briefly, constructed points are associated with directions and the Cartesian point is split. In one-dimension each point splits into a point pair compatible with the linear ordering. An application to one-dimensional particle motion is given, with the result that natural topological assumptions force the number of left point, right point transitions to remain locally finite in a continuous motion. In general, Cartesian points are seen to correspond to certain filters on a suitable Boolean algebra. Constructed points correspond to ultrafilters. Thus, point construction gives a natural refinement of the Cartesian systems.

  11. Software for Automated Generation of Cartesian Meshes

    NASA Technical Reports Server (NTRS)

    Aftosmis, Michael J.; Melton, John E.; Berger, Marshal J.

    2006-01-01

    Cart3D is a collection of computer programs for generating Cartesian meshes [for computational fluid dynamics (CFD) and other applications] in volumes bounded by solid objects. Aspects of Cart3D at earlier stages of development were reported in "Robust and Efficient Generation of Cartesian Meshes for CFD" (ARC-14275), NASA Tech Briefs, Vol. 23, No. 8 (August 1999), page 30. The geometric input to Cart3D comprises surface triangulations like those commonly generated by computer-aided-design programs. Complexly shaped objects can be represented as assemblies of simpler ones. Cart3D deletes all portions of such an assembled object that are not on the exterior surface. Intersections between components are preserved in the resulting triangulation. A tie-breaking routine unambiguously resolves geometric degeneracies. Then taking the intersected surface triangulation as input, the volume mesh is generated through division of cells of an initially coarse hexahedral grid. Cells are subdivided to refine the grid in regions of increased surface curvature and/or increased flow gradients. Cells that become split into multiple unconnected regions by thin pieces of surface are identified.

  12. Three‐Dimensional Echocardiography and 2D‐3D Speckle‐Tracking Imaging in Chronic Pulmonary Hypertension: Diagnostic Accuracy in Detecting Hemodynamic Signs of Right Ventricular (RV) Failure

    PubMed Central

    Vitarelli, Antonio; Mangieri, Enrico; Terzano, Claudio; Gaudio, Carlo; Salsano, Felice; Rosato, Edoardo; Capotosto, Lidia; D'Orazio, Simona; Azzano, Alessia; Truscelli, Giovanni; Cocco, Nino; Ashurov, Rasul

    2015-01-01

    Background Our aim was to compare three‐dimensional (3D) and 2D and 3D speckle‐tracking (2D‐STE, 3D‐STE) echocardiographic parameters with conventional right ventricular (RV) indexes in patients with chronic pulmonary hypertension (PH), and investigate whether these techniques could result in better correlation with hemodynamic variables indicative of heart failure. Methods and Results Seventy‐three adult patients (mean age, 53±13 years; 44% male) with chronic PH of different etiologies were studied by echocardiography and cardiac catheterization (25 precapillary PH from pulmonary arterial hypertension, 23 obstructive pulmonary heart disease, and 23 postcapillary PH from mitral regurgitation). Thirty healthy subjects (mean age, 54±15 years; 43% male) served as controls. Standard 2D measurements (RV–fractional area change–tricuspid annular plane systolic excursion) and mitral and tricuspid tissue Doppler annular velocities were obtained. RV 3D volumes and global and regional ejection fraction (3D‐RVEF) were determined. RV strains were calculated by 2D‐STE and 3D‐STE. RV 3D global‐free‐wall longitudinal strain (3DGFW‐RVLS), 2D global‐free‐wall longitudinal strain (GFW‐RVLS), apical‐free‐wall longitudinal strain, basal‐free‐wall longitudinal strain, and 3D‐RVEF were lower in patients with precapillary PH (P<0.0001) and postcapillary PH (P<0.01) compared to controls. 3DGFW‐RVLS (hazard ratio 4.6, 95% CI 2.79 to 8.38, P=0.004) and 3D‐RVEF (hazard ratio 5.3, 95% CI 2.85 to 9.89, P=0.002) were independent predictors of mortality. Receiver operating characteristic curves showed that the thresholds offering an adequate compromise between sensitivity and specificity for detecting hemodynamic signs of RV failure were 39% for 3D‐RVEF (AUC 0.89), −17% for 3DGFW‐RVLS (AUC 0.88), −18% for GFW‐RVLS (AUC 0.88), −16% for apical‐free‐wall longitudinal strain (AUC 0.85), 16 mm for tricuspid annular plane systolic

  13. Three-Dimensional Rotation, Twist and Torsion Analyses Using Real-Time 3D Speckle Tracking Imaging: Feasibility, Reproducibility, and Normal Ranges in Pediatric Population

    PubMed Central

    Han, Wei; Gao, Jun; He, Lin; Yang, Yali; Yin, Ping; Xie, Mingxing; Ge, Shuping

    2016-01-01

    Background and Objective The specific aim of this study was to evaluate the feasibility, reproducibility and maturational changes of LV rotation, twist and torsion variables by real-time 3D speckle-tracking echocardiography (RT3DSTE) in children. Methods A prospective study was conducted in 347 consecutive healthy subjects (181 males/156 females, mean age 7.12 ± 5.3 years, and range from birth to 18-years) using RT 3D echocardiography (3DE). The LV rotation, twist and torsion measurements were made off-line using TomTec software. Manual landmark selection and endocardial border editing were performed in 3 planes (apical “2”-, “4”-, and “3”- chamber views) and semi-automated tracking yielded LV rotation, twist and torsion measurements. LV rotation, twist and torsion analysis by RT 3DSTE were feasible in 307 out of 347 subjects (88.5%). Results There was no correlation between rotation or twist and age, height, weight, BSA or heart rate, respectively. However, there was statistically significant, but very modest correlation between LV torsion and age (R2 = 0.036, P< 0.001). The normal ranges were defined for rotation and twist in this cohort, and for torsion for each age group. The intra-observer and inter-observer variabilities for apical and basal rotation, twist and torsion ranged from 7.3% ± 3.8% to 12.3% ± 8.8% and from 8.8% ± 4.6% to 15.7% ± 10.1%, respectively. Conclusions We conclude that analysis of LV rotation, twist and torsion by this new RT3D STE is feasible and reproducible in pediatric population. There is no maturational change in rotation and twist, but torsion decreases with age in this cohort. Further refinement is warranted to validate the utility of this new methodology in more sensitive and quantitative evaluation of congenital and acquired heart diseases in children. PMID:27427968

  14. MRI - 3D Ultrasound - X-ray Image Fusion with Electromagnetic Tracking for Transendocardial Therapeutic Injections: In-vitro Validation and In-vivo Feasibility

    PubMed Central

    Hatt, Charles R.; Jain, Ameet K.; Parthasarathy, Vijay; Lang, Andrew; Raval, Amish N.

    2014-01-01

    Myocardial infarction (MI) is one of the leading causes of death in the world. Small animal studies have shown that stem-cell therapy offers dramatic functional improvement post-MI. An endomyocardial catheter injection approach to therapeutic agent delivery has been proposed to improve efficacy through increased cell retention. Accurate targeting is critical for reaching areas of greatest therapeutic potential while avoiding a life-threatening myocardial perforation. Multimodal image fusion has been proposed as a way to improve these procedures by augmenting traditional intra-operative imaging modalities with high resolution pre-procedural images. Previous approaches have suffered from a lack of real-time tissue imaging and dependence on X-ray imaging to track devices, leading to increased ionizing radiation dose. In this paper, we present a new image fusion system for catheter-based targeted delivery of therapeutic agents. The system registers real-time 3D echocardiography, magnetic resonance, X-ray, and electromagnetic sensor tracking within a single flexible framework. All system calibrations and registrations were validated and found to have target registration errors less than 5 mm in the worst case. Injection accuracy was validated in a motion enabled cardiac injection phantom, where targeting accuracy ranged from 0.57 to 3.81 mm. Clinical feasibility was demonstrated with in-vivo swine experiments, where injections were successfully made into targeted regions of the heart. PMID:23561056

  15. Real-time intensity based 2D/3D registration using kV-MV image pairs for tumor motion tracking in image guided radiotherapy

    NASA Astrophysics Data System (ADS)

    Furtado, H.; Steiner, E.; Stock, M.; Georg, D.; Birkfellner, W.

    2014-03-01

    Intra-fractional respiratorymotion during radiotherapy is one of themain sources of uncertainty in dose application creating the need to extend themargins of the planning target volume (PTV). Real-time tumormotion tracking by 2D/3D registration using on-board kilo-voltage (kV) imaging can lead to a reduction of the PTV. One limitation of this technique when using one projection image, is the inability to resolve motion along the imaging beam axis. We present a retrospective patient study to investigate the impact of paired portal mega-voltage (MV) and kV images, on registration accuracy. We used data from eighteen patients suffering from non small cell lung cancer undergoing regular treatment at our center. For each patient we acquired a planning CT and sequences of kV and MV images during treatment. Our evaluation consisted of comparing the accuracy of motion tracking in 6 degrees-of-freedom(DOF) using the anterior-posterior (AP) kV sequence or the sequence of kV-MV image pairs. We use graphics processing unit rendering for real-time performance. Motion along cranial-caudal direction could accurately be extracted when using only the kV sequence but in AP direction we obtained large errors. When using kV-MV pairs, the average error was reduced from 3.3 mm to 1.8 mm and the motion along AP was successfully extracted. The mean registration time was of 190+/-35ms. Our evaluation shows that using kVMV image pairs leads to improved motion extraction in 6 DOF. Therefore, this approach is suitable for accurate, real-time tumor motion tracking with a conventional LINAC.

  16. Real-time 3D internal marker tracking during arc radiotherapy by the use of combined MV kV imaging

    NASA Astrophysics Data System (ADS)

    Liu, W.; Wiersma, R. D.; Mao, W.; Luxton, G.; Xing, L.

    2008-12-01

    To minimize the adverse dosimetric effect caused by tumor motion, it is desirable to have real-time knowledge of the tumor position throughout the beam delivery process. A promising technique to realize the real-time image guided scheme in external beam radiation therapy is through the combined use of MV and onboard kV beam imaging. The success of this MV-kV triangulation approach for fixed-gantry radiation therapy has been demonstrated. With the increasing acceptance of modern arc radiotherapy in the clinics, a timely and clinically important question is whether the image guidance strategy can be extended to arc therapy to provide the urgently needed real-time tumor motion information. While conceptually feasible, there are a number of theoretical and practical issues specific to the arc delivery that need to be resolved before clinical implementation. The purpose of this work is to establish a robust procedure of system calibration for combined MV and kV imaging for internal marker tracking during arc delivery and to demonstrate the feasibility and accuracy of the technique. A commercially available LINAC equipped with an onboard kV imager and electronic portal imaging device (EPID) was used for the study. A custom built phantom with multiple ball bearings was used to calibrate the stereoscopic MV-kV imaging system to provide the transformation parameters from imaging pixels to 3D world coordinates. The accuracy of the fiducial tracking system was examined using a 4D motion phantom capable of moving in accordance with a pre-programmed trajectory. Overall, spatial accuracy of MV-kV fiducial tracking during the arc delivery process for normal adult breathing amplitude and period was found to be better than 1 mm. For fast motion, the results depended on the imaging frame rates. The RMS error ranged from ~0.5 mm for the normal adult breathing pattern to ~1.5 mm for more extreme cases with a low imaging frame rate of 3.4 Hz. In general, highly accurate real

  17. Electronic Absolute Cartesian Autocollimator

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.

    2006-01-01

    An electronic absolute Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term absolute in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based absolutely on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic absolute Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the

  18. WE-A-17A-10: Fast, Automatic and Accurate Catheter Reconstruction in HDR Brachytherapy Using An Electromagnetic 3D Tracking System

    SciTech Connect

    Poulin, E; Racine, E; Beaulieu, L; Binnekamp, D

    2014-06-15

    Purpose: In high dose rate brachytherapy (HDR-B), actual catheter reconstruction protocols are slow and errors prompt. The purpose of this study was to evaluate the accuracy and robustness of an electromagnetic (EM) tracking system for improved catheter reconstruction in HDR-B protocols. Methods: For this proof-of-principle, a total of 10 catheters were inserted in gelatin phantoms with different trajectories. Catheters were reconstructed using a Philips-design 18G biopsy needle (used as an EM stylet) and the second generation Aurora Planar Field Generator from Northern Digital Inc. The Aurora EM system exploits alternating current technology and generates 3D points at 40 Hz. Phantoms were also scanned using a μCT (GE Healthcare) and Philips Big Bore clinical CT system with a resolution of 0.089 mm and 2 mm, respectively. Reconstructions using the EM stylet were compared to μCT and CT. To assess the robustness of the EM reconstruction, 5 catheters were reconstructed twice and compared. Results: Reconstruction time for one catheter was 10 seconds or less. This would imply that for a typical clinical implant of 17 catheters, the total reconstruction time would be less than 3 minutes. When compared to the μCT, the mean EM tip identification error was 0.69 ± 0.29 mm while the CT error was 1.08 ± 0.67 mm. The mean 3D distance error was found to be 0.92 ± 0.37 mm and 1.74 ± 1.39 mm for the EM and CT, respectively. EM 3D catheter trajectories were found to be significantly more accurate (unpaired t-test, p < 0.05). A mean difference of less than 0.5 mm was found between successive EM reconstructions. Conclusion: The EM reconstruction was found to be faster, more accurate and more robust than the conventional methods used for catheter reconstruction in HDR-B. This approach can be applied to any type of catheters and applicators. We would like to disclose that the equipments, used in this study, is coming from a collaboration with Philips Medical.

  19. Tracking the dynamic seroma cavity using fiducial markers in patients treated with accelerated partial breast irradiation using 3D conformal radiotherapy

    SciTech Connect

    Yue, Ning J.; Haffty, Bruce G.; Goyal, Sharad

    2013-02-15

    Purpose: The purpose of the present study was to perform an analysis of the changes in the dynamic seroma cavity based on fiducial markers in early stage breast cancer patients treated with accelerated partial breast irradiation (APBI) using three-dimensional conformal external beam radiotherapy (3D-CRT). Methods: A prospective, single arm trial was designed to investigate the utility of gold fiducial markers in image guided APBI using 3D-CRT. At the time of lumpectomy, four to six suture-type gold fiducial markers were sutured to the walls of the cavity. Patients were treated with a fractionation scheme consisting of 15 fractions with a fractional dose of 333 cGy. Treatment design and planning followed NSABP/RTOG B-39 guidelines. During radiation treatment, daily kV imaging was performed and the markers were localized and tracked. The change in distance between fiducial markers was analyzed based on the planning CT and daily kV images. Results: Thirty-four patients were simulated at an average of 28 days after surgery, and started the treatment on an average of 39 days after surgery. The average intermarker distance (AiMD) between fiducial markers was strongly correlated to seroma volume. The average reduction in AiMD was 19.1% (range 0.0%-41.4%) and 10.8% (range 0.0%-35.6%) for all the patients between simulation and completion of radiotherapy, and between simulation and beginning of radiotherapy, respectively. The change of AiMD fits an exponential function with a half-life of seroma shrinkage. The average half-life for seroma shrinkage was 15 days. After accounting for the reduction which started to occur after surgery through CT simulation and treatment, radiation was found to have minimal impact on the distance change over the treatment course. Conclusions: Using the marker distance change as a surrogate for seroma volume, it appears that the seroma cavity experiences an exponential reduction in size. The change in seroma size has implications in the size of

  20. Tracking Efficiency And Charge Sharing of 3D Silicon Sensors at Different Angles in a 1.4T Magnetic Field

    SciTech Connect

    Gjersdal, H.; Bolle, E.; Borri, M.; Da Via, C.; Dorholt, O.; Fazio, S.; Grenier, P.; Grinstein, S. Hansson, P.; Hasi, J.; Hugging, F.; Jackson, P.; Kenney, C.; Kocian, M.; La Rosa, A.; Mastroberardino, A.; Nordahl, P.; Rivero, F.; Rohne, O.; Sandaker, H.; Sjobaek, K.; /Oslo U. /Prague, Tech. U. /SLAC /Bonn U. /SUNY, Stony Brook /Bonn U. /SLAC

    2012-05-07

    A 3D silicon sensor fabricated at Stanford with electrodes penetrating throughout the entire silicon wafer and with active edges was tested in a 1.4 T magnetic field with a 180 GeV/c pion beam at the CERN SPS in May 2009. The device under test was bump-bonded to the ATLAS pixel FE-I3 readout electronics chip. Three readout electrodes were used to cover the 400 {micro}m long pixel side, this resulting in a p-n inter-electrode distance of {approx} 71 {micro}m. Its behavior was confronted with a planar sensor of the type presently installed in the ATLAS inner tracker. Time over threshold, charge sharing and tracking efficiency data were collected at zero and 15{sup o} angles with and without magnetic field. The latest is the angular configuration expected for the modules of the Insertable B-Layer (IBL) currently under study for the LHC phase 1 upgrade expected in 2014.

  1. Quantitative Evaluation of 3D Mouse Behaviors and Motor Function in the Open-Field after Spinal Cord Injury Using Markerless Motion Tracking

    PubMed Central

    Sheets, Alison L.; Lai, Po-Lun; Fisher, Lesley C.; Basso, D. Michele

    2013-01-01

    Thousands of scientists strive to identify cellular mechanisms that could lead to breakthroughs in developing ameliorative treatments for debilitating neural and muscular conditions such as spinal cord injury (SCI). Most studies use rodent models to test hypotheses, and these are all limited by the methods available to evaluate animal motor function. This study’s goal was to develop a behavioral and locomotor assessment system in a murine model of SCI that enables quantitative kinematic measurements to be made automatically in the open-field by applying markerless motion tracking approaches. Three-dimensional movements of eight naïve, five mild, five moderate, and four severe SCI mice were recorded using 10 cameras (100 Hz). Background subtraction was used in each video frame to identify the animal’s silhouette, and the 3D shape at each time was reconstructed using shape-from-silhouette. The reconstructed volume was divided into front and back halves using k-means clustering. The animal’s front Center of Volume (CoV) height and whole-body CoV speed were calculated and used to automatically classify animal behaviors including directed locomotion, exploratory locomotion, meandering, standing, and rearing. More detailed analyses of CoV height, speed, and lateral deviation during directed locomotion revealed behavioral differences and functional impairments in animals with mild, moderate, and severe SCI when compared with naïve animals. Naïve animals displayed the widest variety of behaviors including rearing and crossing the center of the open-field, the fastest speeds, and tallest rear CoV heights. SCI reduced the range of behaviors, and decreased speed (r = .70 p<.005) and rear CoV height (r = .65 p<.01) were significantly correlated with greater lesion size. This markerless tracking approach is a first step toward fundamentally changing how rodent movement studies are conducted. By providing scientists with sensitive, quantitative measurement

  2. Self consistent particles dynamics in/out of the cusp region by using back tracking technics; a global 3D PIC simulation approach

    NASA Astrophysics Data System (ADS)

    Esmaeili, A.; Cai, D.; Lembege, B.; Nishikawa, K.

    2013-12-01

    Large scale three dimensionbal PIC (particle in cell) simulations are presently used in order to analyze the global solar wind-terrestrial magnetosphere intreraction within a full self-consistent approach, and where both electrons and ions are treated as an assembly of individual particles. This 3D kinetic approach allows us to analyze in particular the dynamics and the fine structures of the cusp region when including self consistently not only its whole neighborhood (in the terrestrial magnetosphere) but also the impact of the solar wind and the interplanetary field (IMF) features. Herein, we focuss our attention on the cusp region and in particular on the acceleration and precipitation of particles (both ions and electrons) within the cusp. In present simulations, the IMF is chosen northward, (i.e. where the X -reconnection region is just above the cusp, in the meridian plane). Back-trackings of self-consistent particles are analyzed in details in order to determine (i) which particles (just above the cusp) are precipitated deeply into the cusp, (ii) which populations are injected from the cusp into the nearby tail, (iii) where the particles suffer the largest energisation along their self-consistent trajectories, (iv) where these populations accumulate, and (v) where the most energetic particles are originally coming from. This approach allows to make a traking of particles within the scenario "solar wind-magnetosheath- cusp -nearbytail"; moreover it strongly differs from the standard test particles technics and allows to provide informations not accessible when using full MHD approach. Keywords: Tracing Particles, Particle In Cell (PIC) simulation, double cusp, test particles method, IMF, Solar wind, Magnetosphere

  3. GSRP/David Marshall: Fully Automated Cartesian Grid CFD Application for MDO in High Speed Flows

    NASA Technical Reports Server (NTRS)

    2003-01-01

    With the renewed interest in Cartesian gridding methodologies for the ease and speed of gridding complex geometries in addition to the simplicity of the control volumes used in the computations, it has become important to investigate ways of extending the existing Cartesian grid solver functionalities. This includes developing methods of modeling the viscous effects in order to utilize Cartesian grids solvers for accurate drag predictions and addressing the issues related to the distributed memory parallelization of Cartesian solvers. This research presents advances in two areas of interest in Cartesian grid solvers, viscous effects modeling and MPI parallelization. The development of viscous effects modeling using solely Cartesian grids has been hampered by the widely varying control volume sizes associated with the mesh refinement and the cut cells associated with the solid surface. This problem is being addressed by using physically based modeling techniques to update the state vectors of the cut cells and removing them from the finite volume integration scheme. This work is performed on a new Cartesian grid solver, NASCART-GT, with modifications to its cut cell functionality. The development of MPI parallelization addresses issues associated with utilizing Cartesian solvers on distributed memory parallel environments. This work is performed on an existing Cartesian grid solver, CART3D, with modifications to its parallelization methodology.

  4. FARGO3D: Hydrodynamics/magnetohydrodynamics code

    NASA Astrophysics Data System (ADS)

    Benítez Llambay, Pablo; Masset, Frédéric

    2015-09-01

    A successor of FARGO (ascl:1102.017), FARGO3D is a versatile HD/MHD code that runs on clusters of CPUs or GPUs, with special emphasis on protoplanetary disks. FARGO3D offers Cartesian, cylindrical or spherical geometry; 1-, 2- or 3-dimensional calculations; and orbital advection (aka FARGO) for HD and MHD calculations. As in FARGO, a simple Runge-Kutta N-body solver may be used to describe the orbital evolution of embedded point-like objects. There is no need to know CUDA; users can develop new functions in C and have them translated to CUDA automatically to run on GPUs.

  5. Two-Liquid Cartesian Diver

    ERIC Educational Resources Information Center

    Planinsic, G.; Kos, M.; Jerman, R.

    2004-01-01

    It is quite easy to make a version of the well known Cartesian diver experiment that uses two immiscible liquids. This allows students to test their knowledge of density and pressure in explaining the diver's behaviour. Construction details are presented here together with a mathematical model to explain the observations.

  6. Image based cardiac acceleration map using statistical shape and 3D+t myocardial tracking models; in-vitro study on heart phantom

    NASA Astrophysics Data System (ADS)

    Pashaei, Ali; Piella, Gemma; Planes, Xavier; Duchateau, Nicolas; de Caralt, Teresa M.; Sitges, Marta; Frangi, Alejandro F.

    2013-03-01

    It has been demonstrated that the acceleration signal has potential to monitor heart function and adaptively optimize Cardiac Resynchronization Therapy (CRT) systems. In this paper, we propose a non-invasive method for computing myocardial acceleration from 3D echocardiographic sequences. Displacement of the myocardium was estimated using a two-step approach: (1) 3D automatic segmentation of the myocardium at end-diastole using 3D Active Shape Models (ASM); (2) propagation of this segmentation along the sequence using non-rigid 3D+t image registration (temporal di eomorphic free-form-deformation, TDFFD). Acceleration was obtained locally at each point of the myocardium from local displacement. The framework has been tested on images from a realistic physical heart phantom (DHP-01, Shelley Medical Imaging Technologies, London, ON, CA) in which the displacement of some control regions was known. Good correlation has been demonstrated between the estimated displacement function from the algorithms and the phantom setup. Due to the limited temporal resolution, the acceleration signals are sparse and highly noisy. The study suggests a non-invasive technique to measure the cardiac acceleration that may be used to improve the monitoring of cardiac mechanics and optimization of CRT.

  7. 3D field harmonics

    SciTech Connect

    Caspi, S.; Helm, M.; Laslett, L.J.

    1991-03-30

    We have developed an harmonic representation for the three dimensional field components within the windings of accelerator magnets. The form by which the field is presented is suitable for interfacing with other codes that make use of the 3D field components (particle tracking and stability). The field components can be calculated with high precision and reduced cup time at any location (r,{theta},z) inside the magnet bore. The same conductor geometry which is used to simulate line currents is also used in CAD with modifications more readily available. It is our hope that the format used here for magnetic fields can be used not only as a means of delivering fields but also as a way by which beam dynamics can suggest correction to the conductor geometry. 5 refs., 70 figs.

  8. An adaptive Cartesian control scheme for manipulators

    NASA Technical Reports Server (NTRS)

    Seraji, H.

    1987-01-01

    A adaptive control scheme for direct control of manipulator end-effectors to achieve trajectory tracking in Cartesian space is developed. The control structure is obtained from linear multivariable theory and is composed of simple feedforward and feedback controllers and an auxiliary input. The direct adaptation laws are derived from model reference adaptive control theory and are not based on parameter estimation of the robot model. The utilization of feedforward control and the inclusion of auxiliary input are novel features of the present scheme and result in improved dynamic performance over existing adaptive control schemes. The adaptive controller does not require the complex mathematical model of the robot dynamics or any knowledge of the robot parameters or the payload, and is computationally fast for online implementation with high sampling rates.

  9. Real-time catheter tracking for high-dose-rate prostate brachytherapy using an electromagnetic 3D-guidance device: A preliminary performance study

    SciTech Connect

    Zhou Jun; Sebastian, Evelyn; Mangona, Victor; Yan Di

    2013-02-15

    Purpose: In order to increase the accuracy and speed of catheter reconstruction in a high-dose-rate (HDR) prostate implant procedure, an automatic tracking system has been developed using an electromagnetic (EM) device (trakSTAR, Ascension Technology, VT). The performance of the system, including the accuracy and noise level with various tracking parameters and conditions, were investigated. Methods: A direct current (dc) EM transmitter (midrange model) and a sensor with diameter of 1.3 mm (Model 130) were used in the trakSTAR system for tracking catheter position during HDR prostate brachytherapy. Localization accuracy was assessed under both static and dynamic analyses conditions. For the static analysis, a calibration phantom was used to investigate error dependency on operating room (OR) table height (bottom vs midposition vs top), sensor position (distal tip of catheter vs connector end of catheter), direction [left-right (LR) vs anterior-posterior (AP) vs superior-inferior (SI)], sampling frequency (40 vs 80 vs 120 Hz), and interference from OR equipment (present vs absent). The mean and standard deviation of the localization offset in each direction and the corresponding error vectors were calculated. For dynamic analysis, the paths of five straight catheters were tracked to study the effects of directions, sampling frequency, and interference of EM field. Statistical analysis was conducted to compare the results in different configurations. Results: When interference was present in the static analysis, the error vectors were significantly higher at the top table position (3.3 {+-} 1.3 vs 1.8 {+-} 0.9 mm at bottom and 1.7 {+-} 1.0 mm at middle, p < 0.001), at catheter end position (3.1 {+-} 1.1 vs 1.4 {+-} 0.7 mm at the tip position, p < 0.001), and at 40 Hz sampling frequency (2.6 {+-} 1.1 vs 2.4 {+-} 1.5 mm at 80 Hz and 1.8 {+-} 1.1 at 160 Hz, p < 0.001). So did the mean offset errors in the LR direction (-1.7 {+-} 1.4 vs 0.4 {+-} 0.5 mm in AP and 0

  10. Accuracy and Precision of a Custom Camera-Based System for 2-D and 3-D Motion Tracking during Speech and Nonspeech Motor Tasks

    ERIC Educational Resources Information Center

    Feng, Yongqiang; Max, Ludo

    2014-01-01

    Purpose: Studying normal or disordered motor control requires accurate motion tracking of the effectors (e.g., orofacial structures). The cost of electromagnetic, optoelectronic, and ultrasound systems is prohibitive for many laboratories and limits clinical applications. For external movements (lips, jaw), video-based systems may be a viable…