Science.gov

Sample records for 3d speckle tracking

  1. 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.

  2. 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.

  3. The agreement between 3D, standard 2D and triplane 2D speckle tracking: effects of image quality and 3D volume rate.

    PubMed

    Trache, Tudor; Stöbe, Stephan; Tarr, Adrienn; Pfeiffer, Dietrich; Hagendorff, Andreas

    2014-12-01

    Comparison of 3D and 2D speckle tracking performed on standard 2D and triplane 2D datasets of normal and pathological left ventricular (LV) wall-motion patterns with a focus on the effect that 3D volume rate (3DVR), image quality and tracking artifacts have on the agreement between 2D and 3D speckle tracking. 37 patients with normal LV function and 18 patients with ischaemic wall-motion abnormalities underwent 2D and 3D echocardiography, followed by offline speckle tracking measurements. The values of 3D global, regional and segmental strain were compared with the standard 2D and triplane 2D strain values. Correlation analysis with the LV ejection fraction (LVEF) was also performed. The 3D and 2D global strain values correlated good in both normally and abnormally contracting hearts, though systematic differences between the two methods were observed. Of the 3D strain parameters, the area strain showed the best correlation with the LVEF. The numerical agreement of 3D and 2D analyses varied significantly with the volume rate and image quality of the 3D datasets. The highest correlation between 2D and 3D peak systolic strain values was found between 3D area and standard 2D longitudinal strain. Regional wall-motion abnormalities were similarly detected by 2D and 3D speckle tracking. 2DST of triplane datasets showed similar results to those of conventional 2D datasets. 2D and 3D speckle tracking similarly detect normal and pathological wall-motion patterns. Limited image quality has a significant impact on the agreement between 3D and 2D numerical strain values.

  4. Methods for using 3-D ultrasound speckle tracking in biaxial mechanical testing of biological tissue samples.

    PubMed

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

    2015-04-01

    Being multilayered and anisotropic, biological tissues such as cardiac and arterial walls are structurally complex, making the 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.

  5. The role of 3D and speckle tracking echocardiography in cardiac amyloidosis: a case report.

    PubMed

    Nucci, E M; Lisi, M; Cameli, M; Baldi, L; Puccetti, L; Mondillo, S; Favilli, R; Lunghetti, S

    2014-01-01

    Cardiac amyloidosis (CA) is a disorder characterized by amyloid fibrils deposition in cardiac interstitium; it results in a restrictive cardiomyopathy with heart failure (HF) and conduction abnormalities. The "gold standard" for diagnosis of CA is myocardial biopsy but possible sampling errors and procedural risks, limit it's use. Magnetic resonance (RMN) offers more information than traditional echocardiography and allows diagnosis of CA but often it's impossible to perform. We report the case of a man with HF and symptomatic bradyarrhythmia that required an urgent pacemaker implant. Echocardiography was strongly suggestive of CA but wasn't impossible to perform an RMN to confirm this hypothesis because the patient was implanted with a definitive pacemaker. So was performed a Speckle Tracking Echocardiography (STE) and a 3D echocardiography: STE allows to differentiate CA from others hypertrophic cardiomyopathy by longitudinal strain value < 12% and 3D echocardiography shows regional left ventricular dyssynchrony with a characteristic temporal pattern of dispersion of regional volume systolic change. On the basis of these results, finally was performed an endomyocardial biopsy that confirmed the diagnosis of CA. This case underlines the importance of news, noninvasive techniques such as eco 3D and STE for early diagnosis of CA, especially when RMN cannot be performed.

  6. 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

  7. 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.

  8. Quantification of Coupled Stiffness and Fiber Orientation Remodeling in Hypertensive Rat Right-Ventricular Myocardium Using 3D Ultrasound Speckle Tracking with Biaxial Testing

    PubMed Central

    Park, Dae Woo; Sebastiani, Andrea; Yap, Choon Hwai; Simon, Marc A.; Kim, Kang

    2016-01-01

    Mechanical and structural changes of right ventricular (RV) in response to pulmonary hypertension (PH) are inadequately understood. While current standard biaxial testing provides information on the mechanical behavior of RV tissues using surface markers, it is unable to fully assess structural and mechanical properties across the full tissue thickness. In this study, the mechanical and structural properties of normotensive and pulmonary hypertension right ventricular (PHRV) myocardium through its full thickness were examined using mechanical testing combined with 3D ultrasound speckle tracking (3D-UST). RV pressure overload was induced in Sprague–Dawley rats by pulmonary artery (PA) banding. The second Piola–Kirchhoff stress tensors and Green-Lagrangian strain tensors were computed in the RV myocardium using the biaxial testing combined with 3D-UST. A previously established non-linear curve-fitting algorithm was applied to fit experimental data to a Strain Energy Function (SEF) for computation of myofiber orientation. The fiber orientations obtained by the biaxial testing with 3D-UST compared well with the fiber orientations computed from the histology. In addition, the re-orientation of myofiber in the right ventricular free wall (RVFW) along longitudinal direction (apex-to-outflow-tract direction) was noticeable in response to PH. For normotensive RVFW samples, the average fiber orientation angles obtained by 3D-UST with biaxial test spiraled from 20° at the endo-cardium to -42° at the epi-cardium (Δ = 62°). For PHRV samples, the average fiber orientation angles obtained by 3D-UST with biaxial test had much less spiral across tissue thickness: 3° at endo-cardium to -7° at epi-cardium (Δ = 10°, P<0.005 compared to normotensive). PMID:27780271

  9. Accuracy of real-time single- and multi-beat 3-d speckle tracking echocardiography in vitro.

    PubMed

    Hjertaas, Johannes Just; Fosså, Henrik; Dybdahl, Grete Lunestad; Grüner, Renate; Lunde, Per; Matre, Knut

    2013-06-01

    With little data published on the accuracy of cardiac 3-D strain measurements, we investigated the agreement between 3-D echocardiography and sonomicrometry in an in vitro model with a polyvinyl alcohol phantom. A cardiac scanner with a 3-D probe was used to acquire recordings at 15 different stroke volumes at a heart rate of 60 beats/min, and eight different stroke volumes at a heart rate of 120 beats/min. Sonomicrometry was used as a reference, monitoring longitudinal, circumferential and radial lengths. Both single- and multi-beat acquisitions were recorded. Strain values were compared with sonomicrometer strain using linear correlation coefficients and Bland-Altman analysis. Multi-beat acquisition showed good agreement, whereas real-time images showed less agreement. The best correlation was obtained for a heart rate 60 of beats/min at a volume rate 36.6 volumes/s.

  10. 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

  11. Computer acquisition of 3D images utilizing dynamic speckles

    NASA Astrophysics Data System (ADS)

    Kamshilin, Alexei A.; Semenov, Dmitry V.; Nippolainen, Ervin; Raita, Erik

    2006-05-01

    We present novel technique for fast non-contact and continuous profile measurements of rough surfaces by use of dynamic speckles. The dynamic speckle pattern is generated when the laser beam scans the surface under study. The most impressive feature of the proposed technique is its ability to work at extremely high scanning speed of hundreds meters per second. The technique is based on the continuous frequency measurements of the light-power modulation after spatial filtering of the scattered light. The complete optical-electronic system was designed and fabricated for fast measurement of the speckles velocity, its recalculation into the distance, and further data acquisition into computer. The measured surface profile is displayed in a PC monitor in real time. The response time of the measuring system is below 1 μs. Important parameters of the system such as accuracy, range of measurements, and spatial resolution are analyzed. Limits of the spatial filtering technique used for continuous tracking of the speckle-pattern velocity are shown. Possible ways of further improvement of the measurements accuracy are demonstrated. Owing to its extremely fast operation, the proposed technique could be applied for online control of the 3D-shape of complex objects (e.g., electronic circuits) during their assembling.

  12. Left Atrial Deformation Analysis in Patients with Corrected Tetralogy of Fallot by 3D Speckle-Tracking Echocardiography (from the MAGYAR-Path Study)

    PubMed Central

    Havasi, Kálmán; Domsik, Péter; Kalapos, Anita; McGhie, Jackie S.; Roos-Hesselink, Jolien W.; Forster, Tamás; Nemes, Attila

    2017-01-01

    Background Three-dimensional (3D) echocardiography coupled with speckle-tracking echocardiographic (STE) capability is a novel methodology which has been demontrated to be useful for the assessment of left atrial (LA) volumes and functional properties. There is increased scientific interest on myocardial deformation analysis in adult patients with corrected tetralogy of Fallot (cTOF). Objectives To compare LA volumes, volume-based functional properties and strain parameters between cTOF patients and age- and gender-matched healthy controls. Methods The study population consisted of 19 consecutive adult patients with cTOF in sinus rhythm nursing at the University of Szeged, Hungary (mean age: 37.9 ± 11.3 years, 8 men, who had repair at the age of 4.1 ± 2.5 years). They all had undergone standard transthoracic two-dimensional Doppler echocardiographic study extended with 3DSTE. Their results were compared to 23 age- and gender-matched healthy controls (mean age: 39.2 ± 10.6 years, 14 men). Results Increased LA volumes and reduced LA emptying fractions respecting cardiac cycle could be demonstrated in cTOF patients compared to controls. LA stroke volumes featuring all LA functions showed no differences between the 2 groups examined. LA global and mean segmental uni- and multidirectional peak strains featuring LA reservoir function were found to be diminished in adult patients with cTOF as compared to controls. Similarly to peak strains reduced global and mean segmental LA strains at atrial contraction characterizing atrial booster pump function could be demonstrated in cTOF patients as compared to controls. Conclusions Significant deterioration of all LA functions could be demonstrated in adult patients with cTOF late after repair. PMID:28327874

  13. Detailed Measurement of Wall Strain with 3D Speckle Tracking in the Aortic Root: A Case of Bionic Support for Clinical Decision Making

    PubMed Central

    Vogt, Sebastian; Karatolios, Konstantinos; Wittek, Andreas; Blasé, Christopher; Ramaswamy, Anette; Mirow, Nikolas; Moosdorf, Rainer

    2016-01-01

    Three-dimensional (3D) wall motion tracking (WMT) based on ultrasound imaging enables estimation of aortic wall motion and deformation. It provides insights into changes in vascular compliance and vessel wall properties essential for understanding the pathogenesis and progression of aortic diseases. In this report, we employed the novel 3D WMT analysis on the ascending aorta aneurysm (AA) to estimate local aortic wall motion and strain in case of a patient scheduled for replacement of the aortic root. Although progression of the diameter indicates surgical therapy, at present we addressed the question for optimal surgical time point. According to the data, AA in our case has enlarged diameter and subsequent reduced circumferential wall strain, but area tracking data reveals almost normal elastic properties. Virtual remodeling of the aortic root opens a play list for different loading conditions to determine optimal surgical intervention in time. PMID:28018834

  14. Nonlocal means filter-based speckle tracking.

    PubMed

    Afsham, Narges; Rasoulian, Abtin; Najafi, Mohammad; Abolmaesumi, Purang; Rohling, Robert

    2015-08-01

    The objective of sensorless freehand 3-D ultrasound imaging is to eliminate the need for additional tracking hardware and reduce cost and complexity. However, the accuracy of current out-of-plane pose estimation is main obstacle for full 6-degree-of-freedom (DoF) tracking. We propose a new filter-based speckle tracking framework to increase the accuracy of out-of-plane displacement estimation. In this framework, we use the displacement estimation not only for the specific speckle pattern, but for the entire image. We develop a nonlocal means (NLM) filter based on a probabilistic normal variance mixture model of ultrasound, known as Rician-inverse Gaussian (RiIG). To aggregate the local displacement estimations, Stein's unbiased risk estimate (SURE) is used as a quality measure of the estimations. We derive an explicit analytical form of SURE for the RiIG model and use it as a weight factor. The proposed filter-based speckle tracking framework is formulated and evaluated for three commonly used noise models, including the RiIG model. The out-of-plane estimations are compared with our previously proposed model-based algorithm in a set of ex vivo experiments for different tissue types. We show that the proposed RiIG filter-based method is more accurate and less tissue-dependent than the other methods. The proposed method is also evaluated in vivo on the spines of five different subjects to assess the feasibility of a clinical application. The 6-DoF transform parameters are estimated and compared with the electromagnetic tracker measurements. The results show higher tracking accuracy for typical small lateral displacements and tilt rotations between image pairs.

  15. Speckle size of light scattered from 3D rough objects.

    PubMed

    Zhang, Geng; Wu, Zhensen; Li, Yanhui

    2012-02-13

    From scalar Helmholtz integral relation and by coordinate system transformation, this paper begins with a derivation of the far-zone speckle field in the observation plane perpendicular to the scattering direction from an arbitrarily shaped conducting rough object illuminated by a plane wave illumination, followed by the spatial correlation function of the speckle intensity to obtain the speckle size from the objects. Especially, the specific expressions for the speckle sizes of light backscattered from spheres, cylinders and cones are obtained in detail showing that the speckle size along one direction in the observation plane is proportional to the incident wavelength and the distance between the object and the observation plane, and is inverse proportional to the maximal illuminated dimension of the object parallel to the direction. In addition, the shapes of the speckle of the rough objects with different shapes are different. The investigation on the speckle size in this paper will be useful for the statistical properties of speckle from complicated rough objects and the speckle imaging to target detection and identification.

  16. Continuous ultrasound speckle tracking with Gaussian mixtures.

    PubMed

    Schretter, Colas; Sun, Jianyong; Bundervoet, Shaun; Dooms, Ann; Schelkens, Peter; de Brito Carvalho, Catarina; Slagmolen, Pieter; D'hooge, Jan

    2015-01-01

    Speckle tracking echocardiography (STE) is now widely used for measuring strain, deformations, and motion in cardiology. STE involves three successive steps: acquisition of individual frames, speckle detection, and image registration using speckles as landmarks. This work proposes to avoid explicit detection and registration by representing dynamic ultrasound images as sparse collections of moving Gaussian elements in the continuous joint space-time space. Individual speckles or local clusters of speckles are approximated by a single multivariate Gaussian kernel with associated linear trajectory over a short time span. A hierarchical tree-structured model is fitted to sampled input data such that predicted image estimates can be retrieved by regression after reconstruction, allowing a (bias-variance) trade-off between model complexity and image resolution. The inverse image reconstruction problem is solved with an online Bayesian statistical estimation algorithm. Experiments on clinical data could estimate subtle sub-pixel accurate motion that is difficult to capture with frame-to-frame elastic image registration techniques.

  17. 3-D model-based vehicle tracking.

    PubMed

    Lou, Jianguang; Tan, Tieniu; Hu, Weiming; Yang, Hao; Maybank, Steven J

    2005-10-01

    This paper aims at tracking vehicles from monocular intensity image sequences and presents an efficient and robust approach to three-dimensional (3-D) model-based vehicle tracking. Under the weak perspective assumption and the ground-plane constraint, the movements of model projection in the two-dimensional image plane can be decomposed into two motions: translation and rotation. They are the results of the corresponding movements of 3-D translation on the ground plane (GP) and rotation around the normal of the GP, which can be determined separately. A new metric based on point-to-line segment distance is proposed to evaluate the similarity between an image region and an instantiation of a 3-D vehicle model under a given pose. Based on this, we provide an efficient pose refinement method to refine the vehicle's pose parameters. An improved EKF is also proposed to track and to predict vehicle motion with a precise kinematics model. Experimental results with both indoor and outdoor data show that the algorithm obtains desirable performance even under severe occlusion and clutter.

  18. Speckle Tracking and Transthyretin Amyloid Cardiomyopathy

    PubMed Central

    Rocha, Alexandre Marins; Ferreira, Suzane Garcia; Nacif, Marcelo Souto; Ribeiro, Mario Luiz; de Freitas, Marcos Raimundo Gomes; Mesquita, Cláudio Tinoco

    2017-01-01

    Background Amyloidosis is a disease caused by deposits of insoluble fibrils in extracellular spaces. The most common type of familial amyloidosis is mediated by mutation of transthyretin, especially Val30Met. Symptoms and ejection fraction decrease may occur in cardiac amyloidosis only in case of poor prognosis. Myocardial strain detected by two-dimensional speckle tracking echocardiography can indicate changes in myocardial function at early stages of the disease. Objective To determine the accuracy of left ventricular longitudinal strain by two-dimensional speckle tracking echocardiography in patients with familial amyloidosis caused by Val30Met transthyretin mutation. Methods Eighteen consecutive patients, carriers of transthyretin mutation, were evaluated by two-dimensional speckle tracking echocardiography, by which myocardial strain curves were obtained, following the American Society of Echocardiography recommendations. Results Patients were divided into three groups: 1- Val30Met with cardiac amyloidosis; 2-Val30Met with extracardiac amyloidosis; 3 - Val30Met without evidence of disease. As the three groups were compared by the Mann-Whitney test, we found a statistically significant difference between groups 1 and 2 in the mean longitudinal tension (p=0.01), mean basal longitudinal strain (p=0.014); in mean longitudinal tension and mean longitudinal strain between groups 1 and 3 (p=0.005); and in the ratio of longitudinal strain of apical septum segment to longitudinal strain of basal septum (p=0.041) between groups 2 and 3. Conclusion Left ventricular longitudinal strain detected by two-dimensional speckle tracking echocardiography is able to diagnose left ventricular dysfunction in early stages of familial amyloidosis caused by transthyretin Val30Met mutation. PMID:27992035

  19. Tracking earthquake source evolution in 3-D

    NASA Astrophysics Data System (ADS)

    Kennett, B. L. N.; Gorbatov, A.; Spiliopoulos, S.

    2014-08-01

    Starting from the hypocentre, the point of initiation of seismic energy, we seek to estimate the subsequent trajectory of the points of emission of high-frequency energy in 3-D, which we term the `evocentres'. We track these evocentres as a function of time by energy stacking for putative points on a 3-D grid around the hypocentre that is expanded as time progresses, selecting the location of maximum energy release as a function of time. The spatial resolution in the neighbourhood of a target point can be simply estimated by spatial mapping using the properties of isochrons from the stations. The mapping of a seismogram segment to space is by inverse slowness, and thus more distant stations have a broader spatial contribution. As in hypocentral estimation, the inclusion of a wide azimuthal distribution of stations significantly enhances 3-D capability. We illustrate this approach to tracking source evolution in 3-D by considering two major earthquakes, the 2007 Mw 8.1 Solomons islands event that ruptured across a plate boundary and the 2013 Mw 8.3 event 610 km beneath the Sea of Okhotsk. In each case we are able to provide estimates of the evolution of high-frequency energy that tally well with alternative schemes, but also to provide information on the 3-D characteristics that is not available from backprojection from distant networks. We are able to demonstrate that the major characteristics of event rupture can be captured using just a few azimuthally distributed stations, which opens the opportunity for the approach to be used in a rapid mode immediately after a major event to provide guidance for, for example tsunami warning for megathrust events.

  20. Design and verification of diffractive optical elements for speckle generation of 3-D range sensors

    NASA Astrophysics Data System (ADS)

    Du, Pei-Qin; Shih, Hsi-Fu; Chen, Jenq-Shyong; Wang, Yi-Shiang

    2016-12-01

    The optical projection using speckles is one of the structured light methods that have been applied to three-dimensional (3-D) range sensors. This paper investigates the design and fabrication of diffractive optical elements (DOEs) for generating the light field with uniformly distributed speckles. Based on the principles of computer generated holograms, the iterative Fourier transform algorithm was adopted for the DOE design. It was used to calculate the phase map for diffracting the incident laser beam into a goal pattern with distributed speckles. Four patterns were designed in the study. Their phase maps were first examined by a spatial light modulator and then fabricated on glass substrates by microfabrication processes. Finally, the diffraction characteristics of the fabricated devices were verified. The experimental results show that the proposed methods are applicable to the DOE design of 3-D range sensors. Furthermore, any expected diffraction area and speckle density could be possibly achieved according to the relations presented in the paper.

  1. On feature motion decorrelation in ultrasound speckle tracking.

    PubMed

    Liang, Tianzhu; Yung, Lingsing; Yu, Weichuan

    2013-02-01

    Speckle tracking methods refer to motion tracking methods based on speckle patterns in ultrasound images. They are commonly used in ultrasound based elasticity imaging techniques to reveal mechanical properties of tissues for clinical diagnosis. In speckle tracking, feature motion decorrelation exists when speckle patterns are not identical before and after tissue motion and deformation. Feature motion decorrelation violates the underlying assumption of most speckle tracking methods. Consequently, the estimation accuracy of current methods is greatly limited. In this paper, two types of speckle pattern variations, the geometric transformation and the intensity change of speckle patterns, are studied. We show that a coupled filtering method is able to compensate for both types of variations. It provides accurate strain estimations even when tissue deformation or rotation is extremely large. We also show that in most cases, an affine warping method that only compensates for the geometric transformation is able to achieve a similar performance as the coupled filtering method. Feature motion decorrelation in B-mode images is also studied. Finally, we show that in typical elastography studies, speckle tracking methods without modeling local shearing or rotation will fail when tissue deformation is large.

  2. Emerging role of three-dimensional speckle tracking strain for accurate quantification of left ventricular dyssynchrony.

    PubMed

    Tanaka, Hidekazu; Tatsumi, Kazuhiro; Matsumoto, Kensuke; Kawai, Hiroya; Hirata, Ken-ichi

    2013-10-01

    A case was 53-year-old female with dilated-phase hypertrophic cardiomyopathy. She was classified as New York Heart Association functional class III heart failure despite receiving optimal medical therapy. The electrocardiogram taken showed intraventricular conduction delay with a QRS width of 194 msec. The left ventricular (LV) end-diastolic and systolic volumes, and ejection fraction (EF) were 101 mL, 68 mL, and 32%, respectively. The patient showed no significant mechanical LV dyssynchrony as evidenced by two-dimensional (2D) speckle tracking radial strain, which is defined as the time difference between anterior-septum and posterior wall, of 105 msec (<130 msec). Three-dimensional (3D) speckle tracking radial strain was performed for more detailed LV mechanical dyssynchrony analysis. An especially important finding for 3D speckle tracking radial strain analysis was that the average time-to-peak strain of 5 septum segments at 3 different LV levels (basal-anterior-septum, basal-septum, mid-anterior-septum, mid-septum, apical-septum) was significantly shorter than that of 5 posterolateral segments at 3 different LV levels (basal-posterior, basal-lateral, mid-posterior, mid-lateral, apical-lateral). This time difference between septum and posterolateral wall was 216 msec (204 msec vs. 420 msec), which was considered to indicate significant LV mechanical dyssynchrony (≥130 msec). 12 months after cardiac resynchronization therapy (CRT), EF had improved to 47%, while end-systolic and diastolic volumes had decreased to 88 mL and 47 mL, respectively, so that the patient was classified as a responder. In conclusions, a newly developed 3D speckle tracking strain can provide a comprehensive evaluation of "true" LV mechanical dyssynchrony from pyramidal 3D data sets acquired in the same beat, thus yielding more accurate information than previously possible with the 2D speckle tracking system.

  3. Full-color 3D display using binary phase modulation and speckle reduction

    NASA Astrophysics Data System (ADS)

    Matoba, Osamu; Masuda, Kazunobu; Harada, Syo; Nitta, Kouichi

    2016-06-01

    One of the 3D display systems for full-color reconstruction by using binary phase modulation is presented. The improvement of reconstructed objects is achieved by optimizing the binary phase modulation and accumulating the speckle patterns by changing the random phase distributions. The binary phase pattern is optimized by the modified Frenel ping-pong algorithm. Numerical and experimental demonstrations of full color reconstruction are presented.

  4. 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

  5. 3D Tracking via Shoe Sensing

    PubMed Central

    Li, Fangmin; Liu, Guo; Liu, Jian; Chen, Xiaochuang; Ma, Xiaolin

    2016-01-01

    Most location-based services are based on a global positioning system (GPS), which only works well in outdoor environments. Compared to outdoor environments, indoor localization has created more buzz in recent years as people spent most of their time indoors working at offices and shopping at malls, etc. Existing solutions mainly rely on inertial sensors (i.e., accelerometer and gyroscope) embedded in mobile devices, which are usually not accurate enough to be useful due to the mobile devices’ random movements while people are walking. In this paper, we propose the use of shoe sensing (i.e., sensors attached to shoes) to achieve 3D indoor positioning. Specifically, a short-time energy-based approach is used to extract the gait pattern. Moreover, in order to improve the accuracy of vertical distance estimation while the person is climbing upstairs, a state classification is designed to distinguish the walking status including plane motion (i.e., normal walking and jogging horizontally), walking upstairs, and walking downstairs. Furthermore, we also provide a mechanism to reduce the vertical distance accumulation error. Experimental results show that we can achieve nearly 100% accuracy when extracting gait patterns from walking/jogging with a low-cost shoe sensor, and can also achieve 3D indoor real-time positioning with high accuracy. PMID:27801839

  6. Speckle Tracking Echocardiography of the Right Atrium: The Neglected Chamber.

    PubMed

    Rai, Aitzaz Bin Sultan; Lima, Eduardo; Munir, Farrukh; Faisal Khan, Anum; Waqas, Ahmed; Bughio, Sara; ul Haq, Ehtesham; Attique, Hassan Bin; Rahman, Zia Ur

    2015-11-01

    The right atrium (RA) plays a pivotal role in electromechanical and endocrine regulation of the heart. Its peculiar anatomical features and phasic mechanical function make it distinct from ventricles. Various invasive and noninvasive techniques have been used to elucidate RA structure and function. Of these modalities, echocardiography has distinct advantages over others. Several conventional measures of RA function through echocardiography have been described in the literature, but they are load dependent. A relatively new technique is speckle tracking-derived strain, which is relatively less dependent on loading conditions. Speckle tracking echocardiography tracks acoustic scatters (speckles) of myocardium frame-by-frame to calculate strain or deformation of the myocardium. Speckle tracking echocardiography has been used extensively for strain assessment of the right and left ventricle to detect subtle disease pathology, to gain mechanistic insight, as a marker of ischemic metabolic memory, as an endpoint in clinical trials, and as a functional assessment tool. The RA is a relatively neglected chamber, as it is mostly studied for assessment of atrial mass lesions, for electrophysiological studies, and in animal models for physiological assessment. However, its role in the systolic and diastolic function of the right heart, pulmonary vascular pathology, congenital heart diseases, and combined electromechanical activation phenomena has been less explored or unexplored. Speckle tracking echocardiography is an ideal tool for the assessment of the RA because of its regional and global functional characterization, angle independence, and high temporal resolution.

  7. Is speckle tracking actually helpful for cardiac resynchronization therapy?

    PubMed

    Tanaka, Hidekazu; Hirata, Ken-Ichi

    2016-06-01

    What is the specific role of echocardiography in cardiac resynchronization therapy (CRT)? CRT has proven to be highly effective for improving symptoms and survival of patients with advanced heart failure (HF) and wide QRS. However, a significant minority of patients do not respond favorably to CRT on the basis of standard clinical selection criteria, including the electrocardiographic QRS width. Subsequently, echocardiographic assessment of left ventricular (LV) dyssynchrony has been considered useful for CRT for selected responders, but findings by multicenter studies suggest that its predictive value was not sufficiently robust to replace routine selection criteria for CRT. A more recent approach, however, using speckle-tracking echocardiography yields more accurate quantification of regional wall contraction. Speckle-tracking approaches have therefore generated a great deal of interest about their clinical applications for CRT. Although reports on speckle tracking have not been included in any recommendations as to whether patients should undergo CRT based on the current guidelines, speckle tracking can play an important supplementary part in CRT on the basis of a case-by-case clinical decision for challenging cases. Here, we review the strengths of speckle-tracking methods, and their current potential for clinical use in CRT.

  8. Reduction of the recorded speckle noise in holographic 3D printer.

    PubMed

    Utsugi, Takeru; Yamaguchi, Masahiro

    2013-01-14

    A holographic 3D printer produces a high-quality 3D image reproduced by a full-color, full-parallax holographic stereogram with high-density light-ray recording. In order to produce a high-resolution holographic stereogram, we have to solve the problem of speckle noise in this system. For equalizing an intensity distribution inside the elementary hologram, the object beam is modulated by a diffuser. However the diffuser typically generates speckles, which is recorded in the holographic stereogram. It is localized behind the reconstructed image as a granularity noise. First we show the problems of some conventional ways for suppressing the granularity noise using a band-limited diffuser, and then we analyze an approach using a moving diffuser for the reduction of this noise. In the result, it is found that recording with a moving diffuser is effective for reducing the granularity noise at infinity of reconstructed image, although an alternative noise occurs. Moreover we propose a new method introducing multiple exposures to suppress the noise effectively.

  9. 3D gaze tracking system for NVidia 3D Vision®.

    PubMed

    Wibirama, Sunu; Hamamoto, Kazuhiko

    2013-01-01

    Inappropriate parallax setting in stereoscopic content generally causes visual fatigue and visual discomfort. To optimize three dimensional (3D) effects in stereoscopic content by taking into account health issue, understanding how user gazes at 3D direction in virtual space is currently an important research topic. In this paper, we report the study of developing a novel 3D gaze tracking system for Nvidia 3D Vision(®) to be used in desktop stereoscopic display. We suggest an optimized geometric method to accurately measure the position of virtual 3D object. Our experimental result shows that the proposed system achieved better accuracy compared to conventional geometric method by average errors 0.83 cm, 0.87 cm, and 1.06 cm in X, Y, and Z dimensions, respectively.

  10. Clutter filtering influence on blood velocity estimation using speckle tracking.

    PubMed

    Fadnes, Solveig; Bjærum, Steinar; Torp, Hans; Lovstakken, Lasse

    2015-12-01

    Blood speckle tracking has shown potential for solving the angle-dependency limitation in color flow imaging. However, as clutter filtering is still Doppler-based, flow velocities at near-perpendicular beam-to-flow angles can be severely attenuated. It is shown that the clutter filter also alters the speckle appearance through a decrease in the lateral imaging bandwidth, leading to poorer lateral resolution and thus tracking performance. Interestingly, at perpendicular beam-to-flow angles lateral band-pass characteristics are inferred, and the resulting lateral amplitude modulation could help improve tracking estimates. Simulations and flow phantom experiments showed that substantially improved results could be achieved by utilizing time-variant clutter filters (e.g., polynomial regression filters) despite the inherent decorrelation inferred by these filters, but only for higher ensemble sizes (N > 36). We found that, compared with color flow imaging, speckle tracking could yield consistent estimates well below the clutter filter cutoff, but with a higher variance attributed to the low signalto- noise ratio inferred by filter attenuation. Overall, provided that a low f-number and high ensemble lengths (N approx. > 36) can be used, speckle tracking can consistently provide angle- independent flow velocity estimates, limited only by a lower bound on the flow velocity itself.

  11. Speckle tracking and speckle content based composite strain imaging for solid and fluid filled lesions.

    PubMed

    Rabbi, Md Shifat-E; Hasan, Md Kamrul

    2017-02-01

    Strain imaging though for solid lesions provides an effective way for determining their pathologic condition by displaying the tissue stiffness contrast, for fluid filled lesions such an imaging is yet an open problem. In this paper, we propose a novel speckle content based strain imaging technique for visualization and classification of fluid filled lesions in elastography after automatic identification of the presence of fluid filled lesions. Speckle content based strain, defined as a function of speckle density based on the relationship between strain and speckle density, gives an indirect strain value for fluid filled lesions. To measure the speckle density of the fluid filled lesions, two new criteria based on oscillation count of the windowed radio frequency signal and local variance of the normalized B-mode image are used. An improved speckle tracking technique is also proposed for strain imaging of the solid lesions and background. A wavelet-based integration technique is then proposed for combining the strain images from these two techniques for visualizing both the solid and fluid filled lesions from a common framework. The final output of our algorithm is a high quality composite strain image which can effectively visualize both solid and fluid filled breast lesions in addition to the speckle content of the fluid filled lesions for their discrimination. The performance of our algorithm is evaluated using the in vivo patient data and compared with recently reported techniques. The results show that both the solid and fluid filled lesions can be better visualized using our technique and the fluid filled lesions can be classified with good accuracy.

  12. 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

  13. X-ray Multimodal Tomography Using Speckle-Vector Tracking

    NASA Astrophysics Data System (ADS)

    Berujon, Sebastien; Ziegler, Eric

    2016-04-01

    We demonstrate computerized tomography (CT) reconstructions from absorption, phase, and dark-field signals obtained from scans acquired when the x-ray probe light is modulated with speckle. Two different interlaced schemes are proposed to reduce the number of sample exposures. First, the already demonstrated x-ray speckle-vector tracking (XSVT) concept for projection imaging allows the three signal CT reconstructions from multiple images per projection. Second, a modified XSVT approach is shown to provide absorption and phase reconstructions, this time from a single image per angular projection. Reconstructions from data obtained at a synchrotron facility emphasize the potential of the approaches for the imaging of complex samples.

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

    PubMed Central

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

    2015-01-01

    A metrology system combining three laser speckle measurement techniques for simultaneous determination of 3D shape and micro- and macroscopic deformations is presented. While microscopic deformations are determined by a combination of Digital Holographic Interferometry (DHI) and Digital Speckle Photography (DSP), macroscopic 3D shape, position and deformation are retrieved by photogrammetry based on digital image correlation of a projected laser speckle pattern. The photogrammetrically obtained data extend the measurement range of the DHI-DSP system and also increase the accuracy of the calculation of the sensitivity vector. Furthermore, a precise assignment of microscopic displacements to the object’s macroscopic shape for enhanced visualization is achieved. The approach allows for fast measurements with a simple setup. Key parameters of the system are optimized, and its precision and measurement range are demonstrated. As application examples, the deformation of a mandible model and the shrinkage of dental impression material are measured. PMID:26713197

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

    PubMed

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

    2015-12-01

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

  16. 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.

  17. Deployment of a 3D tag tracking method utilising RFID

    NASA Astrophysics Data System (ADS)

    Wasif Reza, Ahmed; Yun, Teoh Wei; Dimyati, Kaharudin; Geok Tan, Kim; Ariffin Noordin, Kamarul

    2012-04-01

    Recent trend shows that one of the crucial problems faced while using radio frequency to track the objects is the inconsistency of the signal strength reception, which can be mainly due to the environmental factors and the blockage, which always have the most impact on the tracking accuracy. Besides, three dimensions are more relevant to a warehouse scanning. Therefore, this study proposes a highly accurate and new three-dimensional (3D) radio frequency identification-based indoor tracking system with the consideration of different attenuation factors and obstacles. The obtained results show that the proposed system yields high-quality performance with an average error as low as 0.27 m (without obstacles and attenuation effects). The obtained results also show that the proposed tracking technique can achieve relatively lower errors (0.4 and 0.36 m, respectively) even in the presence of the highest attenuation effect, e = 3.3 or when the environment is largely affected by 50% of the obstacles. Furthermore, the superiority of the proposed 3D tracking system has been proved by comparing with other existing approaches. The 3D tracking system proposed in this study can be applicable to a warehouse scanning.

  18. 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.

  19. X-ray pulse wavefront metrology using speckle tracking.

    PubMed

    Berujon, Sebastien; Ziegler, Eric; Cloetens, Peter

    2015-07-01

    An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology.

  20. X-ray pulse wavefront metrology using speckle tracking

    PubMed Central

    Berujon, Sebastien; Ziegler, Eric; Cloetens, Peter

    2015-01-01

    An instrument allowing the quantitative analysis of X-ray pulsed wavefronts is presented and its processing method explained. The system relies on the X-ray speckle tracking principle to accurately measure the phase gradient of the X-ray beam from which beam optical aberrations can be deduced. The key component of this instrument, a semi-transparent scintillator emitting visible light while transmitting X-rays, allows simultaneous recording of two speckle images at two different propagation distances from the X-ray source. The speckle tracking procedure for a reference-less metrology mode is described with a detailed account on the advanced processing schemes used. A method to characterize and compensate for the imaging detector distortion, whose principle is also based on speckle, is included. The presented instrument is expected to find interest at synchrotrons and at the new X-ray free-electron laser sources under development worldwide where successful exploitation of beams relies on the availability of an accurate wavefront metrology. PMID:26134791

  1. Linear tracking for 3-D medical ultrasound imaging.

    PubMed

    Huang, Qing-Hua; Yang, Zhao; Hu, Wei; Jin, Lian-Wen; Wei, Gang; Li, Xuelong

    2013-12-01

    As the clinical application grows, there is a rapid technical development of 3-D ultrasound imaging. Compared with 2-D ultrasound imaging, 3-D ultrasound imaging can provide improved qualitative and quantitative information for various clinical applications. In this paper, we proposed a novel tracking method for a freehand 3-D ultrasound imaging system with improved portability, reduced degree of freedom, and cost. We designed a sliding track with a linear position sensor attached, and it transmitted positional data via a wireless communication module based on Bluetooth, resulting in a wireless spatial tracking modality. A traditional 2-D ultrasound probe fixed to the position sensor on the sliding track was used to obtain real-time B-scans, and the positions of the B-scans were simultaneously acquired when moving the probe along the track in a freehand manner. In the experiments, the proposed method was applied to ultrasound phantoms and real human tissues. The results demonstrated that the new system outperformed a previously developed freehand system based on a traditional six-degree-of-freedom spatial sensor in phantom and in vivo studies, indicating its merit in clinical applications for human tissues and organs.

  2. 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

  3. Motion-compensated speckle tracking via particle filtering

    NASA Astrophysics Data System (ADS)

    Liu, Lixin; Yagi, Shin-ichi; Bian, Hongyu

    2015-07-01

    Recently, an improved motion compensation method that uses the sum of absolute differences (SAD) has been applied to frame persistence utilized in conventional ultrasonic imaging because of its high accuracy and relative simplicity in implementation. However, high time consumption is still a significant drawback of this space-domain method. To seek for a more accelerated motion compensation method and verify if it is possible to eliminate conventional traversal correlation, motion-compensated speckle tracking between two temporally adjacent B-mode frames based on particle filtering is discussed. The optimal initial density of particles, the least number of iterations, and the optimal transition radius of the second iteration are analyzed from simulation results for the sake of evaluating the proposed method quantitatively. The speckle tracking results obtained using the optimized parameters indicate that the proposed method is capable of tracking the micromotion of speckle throughout the region of interest (ROI) that is superposed with global motion. The computational cost of the proposed method is reduced by 25% compared with that of the previous algorithm and further improvement is necessary.

  4. A 3D diamond detector for particle tracking

    NASA Astrophysics Data System (ADS)

    Bachmair, F.; Bäni, L.; Bergonzo, P.; Caylar, B.; Forcolin, G.; Haughton, I.; Hits, D.; Kagan, H.; Kass, R.; Li, L.; Oh, A.; Phan, S.; Pomorski, M.; Smith, D. S.; Tyzhnevyi, V.; Wallny, R.; Whitehead, D.

    2015-06-01

    A novel device using single-crystal chemical vapour deposited diamond and resistive electrodes in the bulk forming a 3D diamond detector is presented. The electrodes of the device were fabricated with laser assisted phase change of diamond into a combination of diamond-like carbon, amorphous carbon and graphite. The connections to the electrodes of the device were made using a photo-lithographic process. The electrical and particle detection properties of the device were investigated. A prototype detector system consisting of the 3D device connected to a multi-channel readout was successfully tested with 120 GeV protons proving the feasibility of the 3D diamond detector concept for particle tracking applications for the first time.

  5. 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.

  6. Combination of 3-D deformation and shape measurement by electronic speckle pattern interferometry for quantitative strain-stress analysis

    NASA Astrophysics Data System (ADS)

    Ettemeyer, Andreas

    2000-01-01

    Laser speckle interferometry as a full-field noncontact measuring technique offers interesting opportunities for strain-stress analysis on components. While its application in material testing and material research has already achieved some acceptance in research and industry, its application to complex industrial components like car bodies, gear boxes, engines, and suspensions has been limited. Basic difficulties have arisen from the relatively large rigid-body movements of components under test, harsh environmental conditions in the real test world, and the often complex shape of the analyzed component, especially in the most interesting areas. The commercial availability of a radically miniaturized 3D speckle interferometer has led to the new laser-optical measuring device, the MicroStarTM, which can be used for quantitative strain-stress measurement on nearly any industrial component. The device uses 3D speckle interferometry to measure the shape and the 3D deformation in the area of interest. The combination of shape and deformation provides all necessary data for quantitative 3D strain analysis. The principle stresses as well as the bending and tensile components of the strains can be easily determined. In this paper, the principle and applications of this new system are presented.

  7. Characterisation of walking loads by 3D inertial motion tracking

    NASA Astrophysics Data System (ADS)

    Van Nimmen, K.; Lombaert, G.; Jonkers, I.; De Roeck, G.; Van den Broeck, P.

    2014-09-01

    The present contribution analyses the walking behaviour of pedestrians in situ by 3D inertial motion tracking. The technique is first tested in laboratory experiments with simultaneous registration of the ground reaction forces. The registered motion of the pedestrian allows for the identification of stride-to-stride variations, which is usually disregarded in the simulation of walking forces. Subsequently, motion tracking is used to register the walking behaviour of (groups of) pedestrians during in situ measurements on a footbridge. The calibrated numerical model of the structure and the information gathered using the motion tracking system enables detailed simulation of the step-by-step pedestrian induced vibrations. Accounting for the in situ identified walking variability of the test-subjects leads to a significantly improved agreement between the measured and the simulated structural response.

  8. 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.

  9. 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.

  10. 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.

  11. Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography.

    PubMed

    Zaitsev, Vladimir Y; Matveyev, Alexandr L; Matveev, Lev A; Gelikonov, Grigory V; Gelikonov, Valentin M; Vitkin, Alex

    2015-07-01

    Feasibility of speckle tracking in optical coherence tomography (OCT) based on digital image correlation (DIC) is discussed in the context of elastography problems. Specifics of applying DIC methods to OCT, compared to processing of photographic images in mechanical engineering applications, are emphasized and main complications are pointed out. Analytical arguments are augmented by accurate numerical simulations of OCT speckle patterns. In contrast to DIC processing for displacement and strain estimation in photographic images, the accuracy of correlational speckle tracking in deformed OCT images is strongly affected by the coherent nature of speckles, for which strain-induced complications of speckle “blinking” and “boiling” are typical. The tracking accuracy is further compromised by the usually more pronounced pixelated structure of OCT scans compared with digital photographic images in classical DIC applications. Processing of complex-valued OCT data (comprising both amplitude and phase) compared to intensity-only scans mitigates these deleterious effects to some degree. Criteria of the attainable speckle tracking accuracy and its dependence on the key OCT system parameters are established.

  12. Deformation-induced speckle-pattern evolution and feasibility of correlational speckle tracking in optical coherence elastography

    NASA Astrophysics Data System (ADS)

    Zaitsev, Vladimir Y.; Matveyev, Alexandr L.; Matveev, Lev A.; Gelikonov, Grigory V.; Gelikonov, Valentin M.; Vitkin, Alex

    2015-07-01

    Feasibility of speckle tracking in optical coherence tomography (OCT) based on digital image correlation (DIC) is discussed in the context of elastography problems. Specifics of applying DIC methods to OCT, compared to processing of photographic images in mechanical engineering applications, are emphasized and main complications are pointed out. Analytical arguments are augmented by accurate numerical simulations of OCT speckle patterns. In contrast to DIC processing for displacement and strain estimation in photographic images, the accuracy of correlational speckle tracking in deformed OCT images is strongly affected by the coherent nature of speckles, for which strain-induced complications of speckle "blinking" and "boiling" are typical. The tracking accuracy is further compromised by the usually more pronounced pixelated structure of OCT scans compared with digital photographic images in classical DIC applications. Processing of complex-valued OCT data (comprising both amplitude and phase) compared to intensity-only scans mitigates these deleterious effects to some degree. Criteria of the attainable speckle tracking accuracy and its dependence on the key OCT system parameters are established.

  13. X-ray phase contrast tomography by tracking near field speckle

    PubMed Central

    Wang, Hongchang; Berujon, Sebastien; Herzen, Julia; Atwood, Robert; Laundy, David; Hipp, Alexander; Sawhney, Kawal

    2015-01-01

    X-ray imaging techniques that capture variations in the x-ray phase can yield higher contrast images with lower x-ray dose than is possible with conventional absorption radiography. However, the extraction of phase information is often more difficult than the extraction of absorption information and requires a more sophisticated experimental arrangement. We here report a method for three-dimensional (3D) X-ray phase contrast computed tomography (CT) which gives quantitative volumetric information on the real part of the refractive index. The method is based on the recently developed X-ray speckle tracking technique in which the displacement of near field speckle is tracked using a digital image correlation algorithm. In addition to differential phase contrast projection images, the method allows the dark-field images to be simultaneously extracted. After reconstruction, compared to conventional absorption CT images, the 3D phase CT images show greatly enhanced contrast. This new imaging method has advantages compared to other X-ray imaging methods in simplicity of experimental arrangement, speed of measurement and relative insensitivity to beam movements. These features make the technique an attractive candidate for material imaging such as in-vivo imaging of biological systems containing soft tissue. PMID:25735237

  14. X-ray phase contrast tomography by tracking near field speckle

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Berujon, Sebastien; Herzen, Julia; Atwood, Robert; Laundy, David; Hipp, Alexander; Sawhney, Kawal

    2015-03-01

    X-ray imaging techniques that capture variations in the x-ray phase can yield higher contrast images with lower x-ray dose than is possible with conventional absorption radiography. However, the extraction of phase information is often more difficult than the extraction of absorption information and requires a more sophisticated experimental arrangement. We here report a method for three-dimensional (3D) X-ray phase contrast computed tomography (CT) which gives quantitative volumetric information on the real part of the refractive index. The method is based on the recently developed X-ray speckle tracking technique in which the displacement of near field speckle is tracked using a digital image correlation algorithm. In addition to differential phase contrast projection images, the method allows the dark-field images to be simultaneously extracted. After reconstruction, compared to conventional absorption CT images, the 3D phase CT images show greatly enhanced contrast. This new imaging method has advantages compared to other X-ray imaging methods in simplicity of experimental arrangement, speed of measurement and relative insensitivity to beam movements. These features make the technique an attractive candidate for material imaging such as in-vivo imaging of biological systems containing soft tissue.

  15. Tracked 3D ultrasound in radio-frequency liver ablation

    NASA Astrophysics Data System (ADS)

    Boctor, Emad M.; Fichtinger, Gabor; Taylor, Russell H.; Choti, Michael A.

    2003-05-01

    Recent studies have shown that radio frequency (RF) ablation is a simple, safe and potentially effective treatment for selected patients with liver metastases. Despite all recent therapeutic advancements, however, intra-procedural target localization and precise and consistent placement of the tissue ablator device are still unsolved problems. Various imaging modalities, including ultrasound (US) and computed tomography (CT) have been tried as guidance modalities. Transcutaneous US imaging, due to its real-time nature, may be beneficial in many cases, but unfortunately, fails to adequately visualize the tumor in many cases. Intraoperative or laparoscopic US, on the other hand, provides improved visualization and target imaging. This paper describes a system for computer-assisted RF ablation of liver tumors, combining navigational tracking of a conventional imaging ultrasound probe to produce 3D ultrasound imaging with a tracked RF ablation device supported by a passive mechanical arm and spatially registered to the ultrasound volume.

  16. Strain measurement of a mouse bone by 3D-electronic speckle pattern interferometry (3D-ESPI)

    NASA Astrophysics Data System (ADS)

    Samala, Praveen R.; Su, Min; Liu, Sheng; Jiang, Hui H.; Yokota, Hiroki; Yang, Lianxiang

    2005-08-01

    Bone is a mechanosensitive tissue that adapts its mass, architecture and mechanical properties to mechanical loading. Appropriate mechanical loads provide an effective means to stimulate bone remodeling and prevent from bone loss. It is controversial whether in situ strain in bone is a critical determinant in enhancement of bone formation, and it is therefore important to evaluate load-driven strain in bone. Using electronic speckle pattern interferometry, we determined high-resolution three-dimensional strains on the mouse femur in response to two loading modalities: an axial loading modality (ALM) and a knee loading modality (KLM). We demonstrated that these two loading modalities induced a different pattern of strain distributions. ALM generated strain in the midshaft of cortical bone, while strains with KLM were concentrated on the distal epiphysis of the mouse femur. Since KLM is capable of enhancing bone formation in cortical bone distant from the knee, the current results indicate that in situ strain is not always necessary for load-driven bone formation.

  17. 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.

  18. The Combination of Speckle Correlation and Fringe Projection for the Measurement of Dynamic 3-D Deformations of Airbag Caps

    NASA Astrophysics Data System (ADS)

    Weber, Herbert; Lichtenberger, Ralf; Wolf, Thomas

    Highly dynamic 3-D deformations of airbag caps in the time interval from the ignition of the airbag to the fracture of the covers have been studied optically. The large out-of-plane displacement compared to the in-plane displacements afforded that the measurement problem was solved by combining white light speckle correlation with fringe projection. In order to record the speckle patterns and the fringe patterns simultaneously by two high speed CCD cameras they had to be separated spectrally. The in-plane displacements yield from the speckle patterns by pattern recognition methods. The out-of-plane displacements can be calculated from the contour of the caps. They yield from the phase maps which are calculated from the fringe patterns. For each time instant only one image is available so that phase shifting procedures to evaluate the fringe patterns could not be applied. In this paper we present a method which is based on the simulation of a phase locked loop (PLL). This results in continuous phase maps without phase unwrapping.

  19. 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.

  20. 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.

  1. Incremental value of resting three-dimensional speckle-tracking echocardiography in detecting coronary artery disease.

    PubMed

    Sun, You-Jing; Wang, Fang; Zhang, Rui-Sheng; Wang, Hai-Yan; Yang, Chen-Guang; Cai, Jie; Zang, Wei-Er; Li, Ming-Zhou; Qi, Xin; Li, Jing

    2015-06-01

    The aim of the present study was to investigate the incremental value of resting three-dimensional speckle-tracking echocardiography (3D-STE) in the detection of early-stage left ventricular dysfunction in patients with coronary artery disease (CAD). A total of 110 patients suspected of having CAD were recruited. All patients underwent 3D-STE and coronary artery angiography (CAG). They were divided to a CAD group and a normal group according to the results of CAG. Using 3D-STE software, the peak values of longitudinal strain (LS), circumferential strain (CS), radial strain (RS) and area strain (AS) and the time to peak value of these strains (T-LS, T-CS, T-RS and T-AS) were measured. A receiver operator characteristic curve (ROC) was used to analyze the sensitivity of these strains for the diagnosis of CAD. ROC analysis indicated that T-LS and composite indices combining the peak strain value and time to peak of LS, CS and AS have diagnostic value for the early detection of CAD; the area under the curve (AUC) values were 0.667, 0.692, 0.621 and 0.672 respectively (P<0.005). The composite index of longitudinal strain demonstrated the highest diagnostic value for CAD with 62% sensitivity and 76% specificity. These results indicate that 3D-STE has incremental value for the diagnosis of CAD in patients at rest.

  2. Tracking tissue section surfaces for automated 3D confocal cytometry

    NASA Astrophysics Data System (ADS)

    Agustin, Ramses; Price, Jeffrey H.

    2002-05-01

    Three-dimensional cytometry, whereby large volumes of tissue would be measured automatically, requires a computerized method for detecting the upper and lower tissue boundaries. In conventional confocal microscopy, the user interactively sets limits for axial scanning for each field-of-view. Biological specimens vary in section thickness, thereby driving the requirement for setting vertical scan limits. Limits could be set arbitrarily large to ensure the entire tissue is scanned, but automatic surface identification would eliminate storing undue numbers of empty optical sections and forms the basis for incorporating lateral microscope stage motion to collect unlimited numbers of stacks. This walk-away automation of 3D confocal scanning for biological imaging is the first sep towards practical, computerized statistical sampling from arbitrarily large tissue volumes. Preliminary results for automatic tissue surface tracking were obtained for phase-contrast microscopy by measuring focus sharpness (previously used for high-speed autofocus by our group). Measurements were taken from 5X5 fields-of-view from hamster liver sections, varying from five to twenty microns in thickness, then smoothed to lessen variations of in-focus information at each axial position. Because image sharpness (as the power of high spatial frequency components) drops across the axial boundaries of a tissue section, mathematical quantities including the full-width at half-maximum, extrema in the first derivative, and second derivative were used to locate the proximal and distal surfaces of a tissue. Results from these tests were evaluated against manual (i.e., visual) determination of section boundaries.

  3. Single tracking location methods suppress speckle noise in shear wave velocity estimation.

    PubMed

    Elegbe, Etana C; McAleavey, Stephen A

    2013-04-01

    In ultrasound-based elastography methods, the estimation of shear wave velocity typically involves the tracking of speckle motion due to an applied force. The errors in the estimates of tissue displacement, and thus shear wave velocity, are generally attributed to electronic noise and decorrelation due to physical processes. We present our preliminary findings on another source of error, namely, speckle-induced bias in phase estimation. We find that methods that involve tracking in a single location, as opposed to multiple locations, are less sensitive to this source of error since the measurement is differential in nature and cancels out speckle-induced phase errors.

  4. 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.

  5. Studying Diastology with Speckle Tracking Echocardiography: The Essentials

    PubMed Central

    Choudhury, Arindam; Magoon, Rohan; Malik, Vishwas; Kapoor, Poonam Malhotra; Ramakrishnan, S

    2017-01-01

    Diastolic dysfunction is common in cardiac disease and an important finding independent of systolic function as it contributes to the signs and symptoms of heart failure. Tissue Doppler mitral early diastolic velocity (Ea) combined with peak transmitral early diastolic velocity (E) to obtain E/Ea ratio provides an estimate of the left ventricular (LV) filling pressure. However, E/Ea has a significant gray zone and less reliable in patients with preserved ejection fraction (>50%). Two-dimensional echocardiographic speckle tracking measure myocardial strain and strain rate (Sr) avoiding the Doppler-associated angulation errors and tethering artifacts. Global myocardial peak diastolic strain (Ds) and diastolic Sr (DSr) at the time of E and isovolumic relaxation combined with E (E/Ds and E/10 DSr) have been recently proposed as novel indices to determine LV filling pressure. The present article elucidates the methodology of studying diastology with strain echocardiography along with the advantages and limitations of the novel technique in light of the available literature. PMID:28074824

  6. 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.

  7. Left ventricular mechanics in isolated mild mitral stenosis: a three dimensional speckle tracking study.

    PubMed

    Poyraz, Esra; Öz, Tuğba Kemaloğlu; Zeren, Gönül; Güvenç, Tolga Sinan; Dönmez, Cevdet; Can, Fatma; Güvenç, Rengin Çetin; Dayı, Şennur Ünal

    2017-03-11

    In a fraction of patients with mild mitral stenosis, left ventricular systolic function deteriorates despite the lack of hemodynamic load imposed by the dysfunctioning valve. Neither the predisposing factors nor the earlier changes in left ventricular contractility were understood adequately. In the present study we aimed to evaluate left ventricular mechanics using three-dimensional (3D) speckle tracking echocardiography. A total of 31 patients with mild rheumatic mitral stenosis and 27 healthy controls were enrolled to the study. All subjects included to the study underwent echocardiographic examination to collect data for two- and three-dimensional speckle-tracking based stain, twist angle and torsion measurements. Data was analyzed offline with a echocardiographic data analysis software. Patients with rheumatic mild MS had lower global longitudinal (p < 0.001) circumferential (p = 0.02) and radial (p < 0.01) strain compared to controls, despite ejection fraction was similar for both groups [(p = 0.45) for three dimensional and (p = 0.37) for two dimensional measurement]. While the twist angle was not significantly different between groups (p = 0.11), left ventricular torsion was significantly higher in mitral stenosis group (p = 0.03). All strain values had a weak but significant positive correlation with mitral valve area measured with planimetry. Subclinical left ventricular systolic dysfunction develops at an early stage in rheumatic mitral stenosis. Further work is needed to elucidate patients at risk for developing overt systolic dysfunction.

  8. 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.

  9. Robust motion tracking based on adaptive speckle decorrelation analysis of OCT signal.

    PubMed

    Wang, Yuewen; Wang, Yahui; Akansu, Ali; Belfield, Kevin D; Hubbi, Basil; Liu, Xuan

    2015-11-01

    Speckle decorrelation analysis of optical coherence tomography (OCT) signal has been used in motion tracking. In our previous study, we demonstrated that cross-correlation coefficient (XCC) between Ascans had an explicit functional dependency on the magnitude of lateral displacement (δx). In this study, we evaluated the sensitivity of speckle motion tracking using the derivative of function XCC(δx) on variable δx. We demonstrated the magnitude of the derivative can be maximized. In other words, the sensitivity of OCT speckle tracking can be optimized by using signals with appropriate amount of decorrelation for XCC calculation. Based on this finding, we developed an adaptive speckle decorrelation analysis strategy to achieve motion tracking with optimized sensitivity. Briefly, we used subsequently acquired Ascans and Ascans obtained with larger time intervals to obtain multiple values of XCC and chose the XCC value that maximized motion tracking sensitivity for displacement calculation. Instantaneous motion speed can be calculated by dividing the obtained displacement with time interval between Ascans involved in XCC calculation. We implemented the above-described algorithm in real-time using graphic processing unit (GPU) and demonstrated its effectiveness in reconstructing distortion-free OCT images using data obtained from a manually scanned OCT probe. The adaptive speckle tracking method was validated in manually scanned OCT imaging, on phantom as well as in vivo skin tissue.

  10. Three-Dimensional Strains in Human Posterior Sclera Using Ultrasound Speckle Tracking

    PubMed Central

    Pavlatos, Elias; Perez, Benjamin Cruz; Morris, Hugh J.; Chen, Hong; Palko, Joel R.; Pan, Xueliang; Weber, Paul A.; Hart, Richard T.; Liu, Jun

    2016-01-01

    Intraocular pressure (IOP) induced strains in the peripapillary sclera may play a role in glaucoma progression. Using inflation testing and ultrasound speckle tracking, the 3D strains in the peripapillary sclera were measured in nine human donor globes. Our results showed that the peripapillary sclera experienced through-thickness compression and meridional stretch during inflation, while minimal circumferential dilation was observed when IOP was increased from 10 to 19 mmHg. The maximum shear was primarily oriented in the through-thickness, meridional cross sections and had a magnitude slightly larger than the first principal strain. The tissue volume had minimal overall change, confirming near-incompressibility of the sclera. Substantial strain heterogeneity was present in the peripapillary region, with local high strain areas likely corresponding to structural heterogeneity caused by traversing blood vessels. These 3D strain characteristics provide new insights into the biomechanical responses of the peripapillary sclera during physiological increases of IOP. Future studies are needed to confirm these findings and investigate the role of these biomechanical characteristics in ocular diseases. PMID:26632258

  11. 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.

  12. Influence of ultrasound speckle tracking strategies for motion and strain estimation.

    PubMed

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

    2016-08-01

    Speckle Tracking is one of the most prominent techniques used to estimate the regional movement of the heart based on ultrasound acquisitions. Many different approaches have been proposed, proving their suitability to obtain quantitative and qualitative information regarding myocardial deformation, motion and function assessment. New proposals to improve the basic algorithm usually focus on one of these three steps: (1) the similarity measure between images and the speckle model; (2) the transformation model, i.e. the type of motion considered between images; (3) the optimization strategies, such as the use of different optimization techniques in the transformation step or the inclusion of structural information. While many contributions have shown their good performance independently, it is not always clear how they perform when integrated in a whole pipeline. Every step will have a degree of influence over the following and hence over the final result. Thus, a Speckle Tracking pipeline must be analyzed as a whole when developing novel methods, since improvements in a particular step might be undermined by the choices taken in further steps. This work presents two main contributions: (1) We provide a complete analysis of the influence of the different steps in a Speckle Tracking pipeline over the motion and strain estimation accuracy. (2) The study proposes a methodology for the analysis of Speckle Tracking systems specifically designed to provide an easy and systematic way to include other strategies. We close the analysis with some conclusions and recommendations that can be used as an orientation of the degree of influence of the models for speckle, the transformation models, interpolation schemes and optimization strategies over the estimation of motion features. They can be further use to evaluate and design new strategy into a Speckle Tracking system.

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

    PubMed Central

    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

  14. A Test in Context: Myocardial Strain Measured by Speckle-Tracking Echocardiography.

    PubMed

    Collier, Patrick; Phelan, Dermot; Klein, Allan

    2017-02-28

    Strain-based imaging techniques (and specifically speckle-tracking echocardiography) have been shown to have clinical utility in a variety of settings. This technique is being embraced and increasingly adopted in many echocardiography laboratories worldwide. This review appraised speckle-tracking echocardiography in a clinical context by providing a critical evaluation of the prognostic and diagnostic insights that this technology can provide. In particular, we discuss the use of speckle-tracking strain in selected areas, such as undifferentiated left ventricular hypertrophy, cardio-oncology, aortic stenosis, and ischemic heart disease. The potential utility of regional and chamber strains (namely segmental left ventricular strain, left atrial strain, and right ventricular strain) are also discussed. Future directions for this technology are explored. Before its clinical application, it is particularly important that physicians be cognizant of the technical challenges and inherent limitations of strain data, which are also addressed here.

  15. High resolution 3D insider detection and tracking.

    SciTech Connect

    Nelson, Cynthia Lee

    2003-09-01

    Vulnerability analysis studies show that one of the worst threats against a facility is that of an active insider during an emergency evacuation. When a criticality or other emergency alarm occurs, employees immediately proceed along evacuation routes to designated areas. Procedures are then implemented to account for all material, classified parts, etc. The 3-Dimensional Video Motion Detection (3DVMD) technology could be used to detect and track possible insider activities during alarm situations, as just described, as well as during normal operating conditions. The 3DVMD technology uses multiple cameras to create 3-dimensional detection volumes or zones. Movement throughout detection zones is tracked and high-level information, such as the number of people and their direction of motion, is extracted. In the described alarm scenario, deviances of evacuation procedures taken by an individual could be immediately detected and relayed to a central alarm station. The insider could be tracked and any protected items removed from the area could be flagged. The 3DVMD technology could also be used to monitor such items as machines that are used to build classified parts. During an alarm, detections could be made if items were removed from the machine. Overall, the use of 3DVMD technology during emergency evacuations would help to prevent the loss of classified items and would speed recovery from emergency situations. Further security could also be added by analyzing tracked behavior (motion) as it corresponds to predicted behavior, e.g., behavior corresponding with the execution of required procedures. This information would be valuable for detecting a possible insider not only during emergency situations, but also during times of normal operation.

  16. 4D ultrasound speckle tracking of intra-fraction prostate motion: a phantom-based comparison with x-ray fiducial tracking using CyberKnife

    NASA Astrophysics Data System (ADS)

    O'Shea, Tuathan P.; Garcia, Leo J.; Rosser, Karen E.; Harris, Emma J.; Evans, Philip M.; Bamber, Jeffrey C.

    2014-04-01

    This study investigates the use of a mechanically-swept 3D ultrasound (3D-US) probe for soft-tissue displacement monitoring during prostate irradiation, with emphasis on quantifying the accuracy relative to CyberKnife® x-ray fiducial tracking. An US phantom, implanted with x-ray fiducial markers was placed on a motion platform and translated in 3D using five real prostate motion traces acquired using the Calypso system. Motion traces were representative of all types of motion as classified by studying Calypso data for 22 patients. The phantom was imaged using a 3D swept linear-array probe (to mimic trans-perineal imaging) and, subsequently, the kV x-ray imaging system on CyberKnife. A 3D cross-correlation block-matching algorithm was used to track speckle in the ultrasound data. Fiducial and US data were each compared with known phantom displacement. Trans-perineal 3D-US imaging could track superior-inferior (SI) and anterior-posterior (AP) motion to ≤0.81 mm root-mean-square error (RMSE) at a 1.7 Hz volume rate. The maximum kV x-ray tracking RMSE was 0.74 mm, however the prostate motion was sampled at a significantly lower imaging rate (mean: 0.04 Hz). Initial elevational (right-left RL) US displacement estimates showed reduced accuracy but could be improved (RMSE <2.0 mm) using a correlation threshold in the ultrasound tracking code to remove erroneous inter-volume displacement estimates. Mechanically-swept 3D-US can track the major components of intra-fraction prostate motion accurately but exhibits some limitations. The largest US RMSE was for elevational (RL) motion. For the AP and SI axes, accuracy was sub-millimetre. It may be feasible to track prostate motion in 2D only. 3D-US also has the potential to improve high tracking accuracy for all motion types. It would be advisable to use US in conjunction with a small (˜2.0 mm) centre-of-mass displacement threshold in which case it would be possible to take full advantage of the accuracy and high imaging

  17. 4D ultrasound speckle tracking of intra-fraction prostate motion: a phantom-based comparison with x-ray fiducial tracking using CyberKnife.

    PubMed

    O'Shea, Tuathan P; Garcia, Leo J; Rosser, Karen E; Harris, Emma J; Evans, Philip M; Bamber, Jeffrey C

    2014-04-07

    This study investigates the use of a mechanically-swept 3D ultrasound (3D-US) probe for soft-tissue displacement monitoring during prostate irradiation, with emphasis on quantifying the accuracy relative to CyberKnife® x-ray fiducial tracking. An US phantom, implanted with x-ray fiducial markers was placed on a motion platform and translated in 3D using five real prostate motion traces acquired using the Calypso system. Motion traces were representative of all types of motion as classified by studying Calypso data for 22 patients. The phantom was imaged using a 3D swept linear-array probe (to mimic trans-perineal imaging) and, subsequently, the kV x-ray imaging system on CyberKnife. A 3D cross-correlation block-matching algorithm was used to track speckle in the ultrasound data. Fiducial and US data were each compared with known phantom displacement. Trans-perineal 3D-US imaging could track superior-inferior (SI) and anterior-posterior (AP) motion to ≤0.81 mm root-mean-square error (RMSE) at a 1.7 Hz volume rate. The maximum kV x-ray tracking RMSE was 0.74 mm, however the prostate motion was sampled at a significantly lower imaging rate (mean: 0.04 Hz). Initial elevational (right-left; RL) US displacement estimates showed reduced accuracy but could be improved (RMSE <2.0 mm) using a correlation threshold in the ultrasound tracking code to remove erroneous inter-volume displacement estimates. Mechanically-swept 3D-US can track the major components of intra-fraction prostate motion accurately but exhibits some limitations. The largest US RMSE was for elevational (RL) motion. For the AP and SI axes, accuracy was sub-millimetre. It may be feasible to track prostate motion in 2D only. 3D-US also has the potential to improve high tracking accuracy for all motion types. It would be advisable to use US in conjunction with a small (∼2.0 mm) centre-of-mass displacement threshold in which case it would be possible to take full advantage of the accuracy and high

  18. 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.

  19. On the dynamics of jellyfish locomotion via 3D particle tracking velocimetry

    NASA Astrophysics Data System (ADS)

    Piper, Matthew; Kim, Jin-Tae; Chamorro, Leonardo P.

    2016-11-01

    The dynamics of jellyfish (Aurelia aurita) locomotion is experimentally studied via 3D particle tracking velocimetry. 3D locations of the bell tip are tracked over 1.5 cycles to describe the jellyfish path. Multiple positions of the jellyfish bell margin are initially tracked in 2D from four independent planes and individually projected in 3D based on the jellyfish path and geometrical properties of the setup. A cubic spline interpolation and the exponentially weighted moving average are used to estimate derived quantities, including velocity and acceleration of the jellyfish locomotion. We will discuss distinctive features of the jellyfish 3D motion at various swimming phases, and will provide insight on the 3D contraction and relaxation in terms of the locomotion, the steadiness of the bell margin eccentricity, and local Reynolds number based on the instantaneous mean diameter of the bell.

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

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  1. Defense Additive Manufacturing: DOD Needs to Systematically Track Department-wide 3D Printing Efforts

    DTIC Science & Technology

    2015-10-01

    Clip Additively Manufactured • The Navy installed a 3D printer aboard the USS Essex to demonstrate the ability to additively develop and produce...desired result and vision to have the capability on the fleet. These officials stated that the Navy plans to install 3D printers on two additional...DEFENSE ADDITIVE MANUFACTURING DOD Needs to Systematically Track Department-wide 3D Printing Efforts Report to

  2. Vision-Based 3D Motion Estimation for On-Orbit Proximity Satellite Tracking and Navigation

    DTIC Science & Technology

    2015-06-01

    printed using the Fortus 400mc 3D rapid- prototyping printer of the NPS Space Systems Academic Group, while the internal structure is made of aluminum...NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS Approved for public release; distribution is unlimited VISION-BASED 3D ...REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE VISION-BASED 3D MOTION ESTIMATION FOR ON-ORBIT PROXIMITY SATELLITE TRACKING

  3. Shunt flow evaluation in congenital heart disease based on two-dimensional speckle tracking.

    PubMed

    Fadnes, Solveig; Nyrnes, Siri Ann; Torp, Hans; Lovstakken, Lasse

    2014-10-01

    High-frame-rate ultrasound speckle tracking was used for quantification of peak velocity in shunt flows resulting from septal defects in congenital heart disease. In a duplex acquisition scheme implemented on a research scanner, unfocused transmit beams and full parallel receive beamforming were used to achieve a frame rate of 107 frames/s for full field-of-view flow images with high accuracy, while also ensuring high-quality focused B-mode tissue imaging. The setup was evaluated in vivo for neonates with atrial and ventricular septal defects. The shunt position was automatically tracked in B-mode images and further used in blood speckle tracking to obtain calibrated shunt flow velocities throughout the cardiac cycle. Validation toward color flow imaging and pulsed wave Doppler with manual angle correction indicated that blood speckle tracking could provide accurate estimates of shunt flow velocities. The approach was less biased by clutter filtering compared with color flow imaging and was able to provide velocity estimates beyond the Nyquist range. Possible placements of sample volumes (and angle corrections) for conventional Doppler resulted in a peak shunt velocity variations of 0.49-0.56 m/s for the ventricular septal defect of patient 1 and 0.38-0.58 m/s for the atrial septal defect of patient 2. In comparison, the peak velocities found from speckle tracking were 0.77 and 0.33 m/s for patients 1 and 2, respectively. Results indicated that complex intraventricular flow velocity patterns could be quantified using high-frame-rate speckle tracking of both blood and tissue movement. This could potentially help increase diagnostic accuracy and decrease inter-observer variability when measuring peak velocity in shunt flows.

  4. Compensation technique for the intrinsic error in ultrasound motion estimation using a speckle tracking method

    NASA Astrophysics Data System (ADS)

    Taki, Hirofumi; Yamakawa, Makoto; Shiina, Tsuyoshi; Sato, Toru

    2015-07-01

    High-accuracy ultrasound motion estimation has become an essential technique in blood flow imaging, elastography, and motion imaging of the heart wall. Speckle tracking has been one of the best motion estimators; however, conventional speckle-tracking methods neglect the effect of out-of-plane motion and deformation. Our proposed method assumes that the cross-correlation between a reference signal and a comparison signal depends on the spatio-temporal distance between the two signals. The proposed method uses the decrease in the cross-correlation value in a reference frame to compensate for the intrinsic error caused by out-of-plane motion and deformation without a priori information. The root-mean-square error of the estimated lateral tissue motion velocity calculated by the proposed method ranged from 6.4 to 34% of that using a conventional speckle-tracking method. This study demonstrates the high potential of the proposed method for improving the estimation of tissue motion using an ultrasound speckle-tracking method in medical diagnosis.

  5. Speckle-Tracking analysis of left ventricular systolic function in the intensive care unit.

    PubMed

    Cinotti, Raphaël; Delater, Adrien; Fortuit, Camille; Roquilly, Antoine; Mahé, Pierre-Joachim; Demeure-dit-Latte, Dominique; Asehnoune, Karim

    2015-01-01

    Speckle-tracking analysis is a new available tool in order to assess left ventricular function in cardiology. Its novelty relies on the technological ability to track natural acoustic markers (known as speckle) within the myocardium during the cardiac cycle. This technology allows the evaluation of myocardium strain during systole and diastole. To date, global longitudinal strain (GLS) has been extensively studied in cardiology. It is now well established that GLS is more sensitive than left ventricular ejection fraction with 2D echocardiography in detecting systolic function impairment. It is also superior to left ventricular ejection fraction in the prediction of major cardio-vascular events. In the intensive care unit (ICU) setting, data are scarce. In experimental model and human studies in septic shock, speckle-tracking analysis suggests that GSL is impaired along with preserved left ventricular ejection fraction. Recent data also suggest that GLS impairment could predict in-ICU mortality in septic shock. In severe subarachnoid haemorrhage patients, speckle-tracking analysis could be more sensitive in detecting stress cardiomyopathy. However, there are many gaps to fill in the critically ill patient. For instance, the influence of mechanical ventilation on GLS is not fully elucidated, and there are, to date, too few data to exactly assess potential GLS alterations on the patient's outcome. Nonetheless, this new tool provides objective and sensitive data with acceptable intra and inter-observer variability and may be of primary interest in the evaluation of left-ventricular systolic function in the ICU.

  6. Head Tracking for 3D Audio Using a GPS-Aided MEMS IMU

    DTIC Science & Technology

    2005-03-01

    Aircraft, Directional Signals, GPS/INS Fusion , GPS/INS Integration, Head Tracking Systems, IMU (Inertial Measurement Unit), Inertial Sensors, MEMS...HEAD TRACKING FOR 3D AUDIO USING A GPS-AIDED MEMS IMU THESIS Jacque M. Joffrion, Captain, USAF AFIT/GE/ENG/05-09 DEPARTMENT OF THE AIR FORCE AIR...the United States Government. AFIT/GE/ENG/05-09 HEAD TRACKING FOR 3D AUDIO USING A GPS-AIDED MEMS IMU THESIS Presented to the Faculty of the Department

  7. 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.

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

    DOE PAGES

    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

  9. 3D-printed concentrators for tracking-integrated CPV modules

    NASA Astrophysics Data System (ADS)

    Apostoleris, Harry; Leland, Julian; Chiesa, Matteo; Stefancich, Marco

    2016-09-01

    We demonstrate 3D-printed nonimaging concentrators and propose a tracking integration scheme to reduce the external tracking requirements of CPV modules. In the proposed system, internal sun tracking is achieved by rotation of the mini-concentrators inside the module by small motors. We discuss the design principles employed in the development of the system, experimentally evaluate the performance of the concentrator prototypes, and propose practical modifications that may be made to improve on-site performance of the devices.

  10. Are biventricular systolic functions impaired in patient with coronoray slow flow? A prospective study with three dimensional speckle tracking.

    PubMed

    Kemaloğlu Öz, Tuğba; Eren, Mehmet; Atasoy, Işıl; Gürol, Tayfun; Soylu, Özer; Dağdeviren, Bahadır

    2017-01-06

    The newly developed three dimensional speckle-tracking echocardiography (3D-STE) technology provides quick and comprehensive quantitative assessment of biventricular myocardial dynamics. The impact of coronary slow flow phenomenon (CSFP) on biventricular functions has not been comprehensively evaluated using this new technology. Therefore, the aim of this study was to evaluate the effects of CSFP on biventricular systolic functions using 3D-STE. Forty patients with CSFP and otherwise normal coronary arteries (NCAs) and 40 age- and sex-matched controls with normal coronary angiograms (CAGs) were prospectively enrolled. Biventricular systolic function was evaluated by 3D-STE. Left ventricular (LV) global longitudinal, circumferential and radial strains, ejection fraction (EF) were significantly lower and LV end-systolic volume (ESV) was significantly higher in the CSFP group compared to the control group. There were no significant differences in LV mass, LV end-diastolic volume (EDV) or LV stroke volume (SV). Additionally, Right ventricular (RV) free wall, septal wall and global longitudinal strains, and RV EF were significantly lower in the CSFP group, but there were no significant differences in RV EDV, ESV and RV SV. The present study demonstrated that CSFP has a notable negative effect on not only 3D strain parameters but also biventricular EF. There was a strong correlation between the strain parameters of the affected vessel's myocardial area and the TIMI frame count of same vessel.

  11. 3D tracking of mating events in wild swarms of the malaria mosquito Anopheles gambiae.

    PubMed

    Butail, Sachit; Manoukis, Nicholas; Diallo, Moussa; Yaro, Alpha S; Dao, Adama; Traoré, Sekou F; Ribeiro, José M; Lehmann, Tovi; Paley, Derek A

    2011-01-01

    We describe an automated tracking system that allows us to reconstruct the 3D kinematics of individual mosquitoes in swarms of Anopheles gambiae. The inputs to the tracking system are video streams recorded from a stereo camera system. The tracker uses a two-pass procedure to automatically localize and track mosquitoes within the swarm. A human-in-the-loop step verifies the estimates and connects broken tracks. The tracker performance is illustrated using footage of mating events filmed in Mali in August 2010.

  12. 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.

  13. Optimal Local Searching for Fast and Robust Textureless 3D Object Tracking in Highly Cluttered Backgrounds.

    PubMed

    Seo, Byung-Kuk; Park, Jong-Il; Hinterstoisser, Stefan; Ilic, Slobodan

    2013-06-13

    Edge-based tracking is a fast and plausible approach for textureless 3D object tracking, but its robustness is still very challenging in highly cluttered backgrounds due to numerous local minima. To overcome this problem, we propose a novel method for fast and robust textureless 3D object tracking in highly cluttered backgrounds. The proposed method is based on optimal local searching of 3D-2D correspondences between a known 3D object model and 2D scene edges in an image with heavy background clutter. In our searching scheme, searching regions are partitioned into three levels (interior, contour, and exterior) with respect to the previous object region, and confident searching directions are determined by evaluating candidates of correspondences on their region levels; thus, the correspondences are searched among likely candidates in only the confident directions instead of searching through all candidates. To ensure the confident searching direction, we also adopt the region appearance, which is efficiently modeled on a newly defined local space (called a searching bundle). Experimental results and performance evaluations demonstrate that our method fully supports fast and robust textureless 3D object tracking even in highly cluttered backgrounds.

  14. Optimal local searching for fast and robust textureless 3D object tracking in highly cluttered backgrounds.

    PubMed

    Seo, Byung-Kuk; Park, Hanhoon; Park, Jong-Il; Hinterstoisser, Stefan; Ilic, Slobodan

    2014-01-01

    Edge-based tracking is a fast and plausible approach for textureless 3D object tracking, but its robustness is still very challenging in highly cluttered backgrounds due to numerous local minima. To overcome this problem, we propose a novel method for fast and robust textureless 3D object tracking in highly cluttered backgrounds. The proposed method is based on optimal local searching of 3D-2D correspondences between a known 3D object model and 2D scene edges in an image with heavy background clutter. In our searching scheme, searching regions are partitioned into three levels (interior, contour, and exterior) with respect to the previous object region, and confident searching directions are determined by evaluating candidates of correspondences on their region levels; thus, the correspondences are searched among likely candidates in only the confident directions instead of searching through all candidates. To ensure the confident searching direction, we also adopt the region appearance, which is efficiently modeled on a newly defined local space (called a searching bundle). Experimental results and performance evaluations demonstrate that our method fully supports fast and robust textureless 3D object tracking even in highly cluttered backgrounds.

  15. Improving segmentation of 3D touching cell nuclei using flow tracking on surface meshes.

    PubMed

    Li, Gang; Guo, Lei

    2012-01-01

    Automatic segmentation of touching cell nuclei in 3D microscopy images is of great importance in bioimage informatics and computational biology. This paper presents a novel method for improving 3D touching cell nuclei segmentation. Given binary touching nuclei by the method in Li et al. (2007), our method herein consists of several steps: surface mesh reconstruction and curvature information estimation; direction field diffusion on surface meshes; flow tracking on surface meshes; and projection of surface mesh segmentation to volumetric images. The method is validated on both synthesised and real 3D touching cell nuclei images, demonstrating its validity and effectiveness.

  16. Laser speckle tracking for monitoring and analysis of retinal photocoagulation

    NASA Astrophysics Data System (ADS)

    Seifert, Eric; Bliedtner, Katharina; Brinkmann, Ralf

    2014-02-01

    Laser coagulation of the retina is an established treatment for several retinal diseases. The absorbed laser energy and thus the induced thermal damage varies with the transmittance and scattering properties of the anterior eye media and with the pigmentation of the fundus. The temperature plays the most important role in the coagulation process. An established approach to measure a mean retinal temperature rise is optoacoustics, however it provides limited information on the coagulation. Phase sensitive OCT potentially offers a three dimensional temporally resolved temperature distribution but is very sensitive to slightest movements which are clinically hard to avoid. We develop an optical technique able to monitor and quantify thermally and coagulation induced tissue movements (expansions and contractions) and changes in the tissue structure by dynamic laser speckle analysis (LSA) offering a 2D map of the affected area. A frequency doubled Nd:YAG laser (532nm) is used for photocoagulation. Enucleated porcine eyes are used as targets. The spot is 100μm. A Helium Neon laser (HeNe) is used for illumination. The backscattered light of a HeNe is captured with a camera and the speckle pattern is analyzed. A Q-switched Nd:YLF laser is used for simultaneous temperature measurements with the optoacoustic approach. Radial tissue movements in the micrometer regime have been observed. The signals evaluation by optical flow algorithms and generalized differences tuned out to be able to distinguish between regions with and without immediate cell damage. Both approaches have shown a sensitivity of 93% and a specificity above 99% at their optimal threshold.

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

    SciTech Connect

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

    2015-12-15

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

  18. Real-time target tracking of soft tissues in 3D ultrasound images based on robust visual information and mechanical simulation.

    PubMed

    Royer, Lucas; Krupa, Alexandre; Dardenne, Guillaume; Le Bras, Anthony; Marchand, Eric; Marchal, Maud

    2017-01-01

    In this paper, we present a real-time approach that allows tracking deformable structures in 3D ultrasound sequences. Our method consists in obtaining the target displacements by combining robust dense motion estimation and mechanical model simulation. We perform evaluation of our method through simulated data, phantom data, and real-data. Results demonstrate that this novel approach has the advantage of providing correct motion estimation regarding different ultrasound shortcomings including speckle noise, large shadows and ultrasound gain variation. Furthermore, we show the good performance of our method with respect to state-of-the-art techniques by testing on the 3D databases provided by MICCAI CLUST'14 and CLUST'15 challenges.

  19. 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".

  20. A Gaussian process guided particle filter for tracking 3D human pose in video.

    PubMed

    Sedai, Suman; Bennamoun, Mohammed; Huynh, Du Q

    2013-11-01

    In this paper, we propose a hybrid method that combines Gaussian process learning, a particle filter, and annealing to track the 3D pose of a human subject in video sequences. Our approach, which we refer to as annealed Gaussian process guided particle filter, comprises two steps. In the training step, we use a supervised learning method to train a Gaussian process regressor that takes the silhouette descriptor as an input and produces multiple output poses modeled by a mixture of Gaussian distributions. In the tracking step, the output pose distributions from the Gaussian process regression are combined with the annealed particle filter to track the 3D pose in each frame of the video sequence. Our experiments show that the proposed method does not require initialization and does not lose tracking of the pose. We compare our approach with a standard annealed particle filter using the HumanEva-I dataset and with other state of the art approaches using the HumanEva-II dataset. The evaluation results show that our approach can successfully track the 3D human pose over long video sequences and give more accurate pose tracking results than the annealed particle filter.

  1. Geometric-model-free tracking of extended targets using 3D lidar measurements

    NASA Astrophysics Data System (ADS)

    Steinemann, Philipp; Klappstein, Jens; Dickmann, Juergen; von Hundelshausen, Felix; Wünsche, Hans-Joachim

    2012-06-01

    Tracking of extended targets in high definition, 360-degree 3D-LIDAR (Light Detection and Ranging) measurements is a challenging task and a current research topic. It is a key component in robotic applications, and is relevant to path planning and collision avoidance. This paper proposes a new method without a geometric model to simultaneously track and accumulate 3D-LIDAR measurements of an object. The method itself is based on a particle filter and uses an object-related local 3D grid for each object. No geometric object hypothesis is needed. Accumulation allows coping with occlusions. The prediction step of the particle filter is governed by a motion model consisting of a deterministic and a probabilistic part. Since this paper is focused on tracking ground vehicles, a bicycle model is used for the deterministic part. The probabilistic part depends on the current state of each particle. A function for calculating the current probability density function for state transition is developed. It is derived in detail and based on a database consisting of vehicle dynamics measurements over several hundreds of kilometers. The adaptive probability density function narrows down the gating area for measurement data association. The second part of the proposed method addresses weighting the particles with a cost function. Different 3D-griddependent cost functions are presented and evaluated. Evaluations with real 3D-LIDAR measurements show the performance of the proposed method. The results are also compared to ground truth data.

  2. 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.

  3. Tracking of wet foam ageing by means of dynamic laser speckle and computer optical mouse

    NASA Astrophysics Data System (ADS)

    Guerrero, Jáder; Plata Planidina, Alexandra; Mejía-Ospino, Enrique; Cabanzo, Rafael

    2013-11-01

    Tracking of wet foam ageing by means of dynamic laser speckle and an optical flow sensor is presented. Using a computer optical mouse, like an optical flow sensor, a strong negative correlation between the average speed of the cursor and the coarsening of bubble was found. We used microscopic images to demonstrate that decreasing of speed is related with increasing of bubble size. The proposed setup allows sensitive measures, is not very expensive and highly portable.

  4. A Microscopic Optically Tracking Navigation System That Uses High-resolution 3D Computer Graphics.

    PubMed

    Yoshino, Masanori; Saito, Toki; Kin, Taichi; Nakagawa, Daichi; Nakatomi, Hirofumi; Oyama, Hiroshi; Saito, Nobuhito

    2015-01-01

    Three-dimensional (3D) computer graphics (CG) are useful for preoperative planning of neurosurgical operations. However, application of 3D CG to intraoperative navigation is not widespread because existing commercial operative navigation systems do not show 3D CG in sufficient detail. We have developed a microscopic optically tracking navigation system that uses high-resolution 3D CG. This article presents the technical details of our microscopic optically tracking navigation system. Our navigation system consists of three components: the operative microscope, registration, and the image display system. An optical tracker was attached to the microscope to monitor the position and attitude of the microscope in real time; point-pair registration was used to register the operation room coordinate system, and the image coordinate system; and the image display system showed the 3D CG image in the field-of-view of the microscope. Ten neurosurgeons (seven males, two females; mean age 32.9 years) participated in an experiment to assess the accuracy of this system using a phantom model. Accuracy of our system was compared with the commercial system. The 3D CG provided by the navigation system coincided well with the operative scene under the microscope. Target registration error for our system was 2.9 ± 1.9 mm. Our navigation system provides a clear image of the operation position and the surrounding structures. Systems like this may reduce intraoperative complications.

  5. 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.

  6. 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.

  7. Handling Motion-Blur in 3D Tracking and Rendering for Augmented Reality.

    PubMed

    Park, Youngmin; Lepetit, Vincent; Woo, Woontack

    2012-09-01

    The contribution of this paper is two-fold. First, we show how to extend the ESM algorithm to handle motion blur in 3D object tracking. ESM is a powerful algorithm for template matching-based tracking, but it can fail under motion blur. We introduce an image formation model that explicitly consider the possibility of blur, and shows its results in a generalization of the original ESM algorithm. This allows to converge faster, more accurately and more robustly even under large amount of blur. Our second contribution is an efficient method for rendering the virtual objects under the estimated motion blur. It renders two images of the object under 3D perspective, and warps them to create many intermediate images. By fusing these images we obtain a final image for the virtual objects blurred consistently with the captured image. Because warping is much faster than 3D rendering, we can create realistically blurred images at a very low computational cost.

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

    PubMed

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

    2015-04-01

    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.

  9. Surveillance, detection, and 3D infrared tracking of bullets, rockets, mortars, and artillery

    NASA Astrophysics Data System (ADS)

    Leslie, Daniel H.; Hyman, Howard; Moore, Fritz; Squire, Mark D.

    2001-09-01

    We describe test results using the FIRST (Fast InfraRed Sniper Tracker) to detect, track, and range to bullets in flight for determining the location of the bullet launch point. The technology developed for the FIRST system can be used to provide detection and accurate 3D track data for other small threat objects including rockets, mortars, and artillery in addition to bullets. We discuss the radiometry and detection range for these objects, and discuss the trade-offs involved in design of the very fast optical system for acquisition, tracking, and ranging of these targets.

  10. Early Cardiac Dysfunction in the Type 1 Diabetic Heart Using Speckle-Tracking Based Strain Imaging

    PubMed Central

    Shepherd, Danielle L.; Nichols, Cody E.; Croston, Tara L.; McLaughlin, Sarah L.; Petrone, Ashley B.; Lewis, Sara E.; Thapa, Dharendra; Long, Dustin M.; Dick, Gregory M.; Hollander, John M.

    2016-01-01

    Enhanced sensitivity in echocardiographic analyses may allow for early detection of changes in cardiac function beyond the detection limits of conventional echocardiographic analyses, particularly in a small animal model. The goal of this study was to compare conventional echocardiographic measurements and speckle-tracking based strain imaging analyses in a small animal model of type 1 diabetes mellitus. Conventional analyses revealed differences in ejection fraction, fractional shortening, cardiac output, and stroke volume in diabetic animals relative to controls at 6-weeks post-diabetic onset. In contrast, when assessing short- and long-axis speckle-tracking based strain analyses, diabetic mice showed changes in average systolic radial strain, radial strain rate, radial displacement, and radial velocity, as well as decreased circumferential and longitudinal strain rate, as early as 1-week post-diabetic onset and persisting throughout the diabetic study. Further, we performed regional analyses for the LV and found that the free wall region was affected in both the short- and long-axis when assessing radial dimension parameters. These changes began 1-week post-diabetic onset and remained throughout the progression of the disease. These findings demonstrate the use of speckle-tracking based strain as an approach to elucidate cardiac dysfunction from a global perspective, identifying left ventricular cardiac regions affected during the progression of type 1 diabetes mellitus earlier than contractile changes detected by conventional echocardiographic measurements. PMID:26654913

  11. Strain assessment in the carotid artery wall using ultrasound speckle tracking: validation in a sheep model

    NASA Astrophysics Data System (ADS)

    Larsson, Matilda; Verbrugghe, Peter; Smoljkić, Marija; Verhoeven, Jelle; Heyde, Brecht; Famaey, Nele; Herijgers, Paul; D'hooge, Jan

    2015-02-01

    The aim of this study was to validate carotid artery strain assessment in-vivo using ultrasound speckle tracking. The left carotid artery of five sheep was exposed and sonomicrometry crystals were sutured onto the artery wall to obtain reference strain. Ultrasound imaging was performed at baseline and stress, followed by strain estimation using an in-house speckle tracking algorithm tuned for vascular applications. The correlation between estimated and reference strain was r = 0.95 (p < 0.001) and r = 0.87 (p < 0.01) for longitudinal and circumferential strain, respectively. Moreover, acceptable limits of agreement were found in Bland-Altman analysis (longitudinally: -0.15 to 0.42%, circumferentially: -0.54 to 0.50%), which demonstrates the feasibility of estimating carotid artery strain using ultrasound speckle tracking. However, further studies are needed to test the algorithm on human in-vivo data and to investigate its potential to detect subclinical cardiovascular disease and characterize atherosclerotic plaques.

  12. Clinical utility of speckle-tracking echocardiography in cardiac resynchronisation therapy.

    PubMed

    Khan, Sitara G; Klettas, Dimitris; Kapetanakis, Stam; Monaghan, Mark J

    2016-03-01

    Cardiac resynchronisation therapy (CRT) can profoundly improve outcome in selected patients with heart failure; however, response is difficult to predict and can be absent in up to one in three patients. There has been a substantial amount of interest in the echocardiographic assessment of left ventricular dyssynchrony, with the ultimate aim of reliably identifying patients who will respond to CRT. The measurement of myocardial deformation (strain) has conventionally been assessed using tissue Doppler imaging (TDI), which is limited by its angle dependence and ability to measure in a single plane. Two-dimensional speckle-tracking echocardiography is a technique that provides measurements of strain in three planes, by tracking patterns of ultrasound interference ('speckles') in the myocardial wall throughout the cardiac cycle. Since its initial use over 15 years ago, it has emerged as a tool that provides more robust, reproducible and sensitive markers of dyssynchrony than TDI. This article reviews the use of two-dimensional and three-dimensional speckle-tracking echocardiography in the assessment of dyssynchrony, including the identification of echocardiographic parameters that may hold predictive potential for the response to CRT. It also reviews the application of these techniques in guiding optimal LV lead placement pre-implant, with promising results in clinical improvement post-CRT.

  13. Acute myocarditis with normal wall motion detected with 2D speckle tracking echocardiography

    PubMed Central

    Niel, Johannes; Aichinger, Josef; Ebner, Christian

    2016-01-01

    Summary We present the case of a 26-year-old male with acute tonsillitis who was referred for coronary angiography because of chest pain, elevated cardiac biomarkers, and biphasic T waves. The patient had no cardiovascular risk factors. Echocardiography showed no wall motion abnormalities and no pericardial effusion. 2D speckle tracking revealed distinct decreased regional peak longitudinal systolic strain in the lateral and posterior walls. Ischemic disease was extremely unlikely in view of his young age, negative family history regarding coronary artery disease, and lack of regional wall motion abnormalities on the conventional 2D echocardiogram. Coronary angiography was deferred as myocarditis was suspected. To confirm the diagnosis, cardiac magnetic resonance tomography (MRT) was performed, showing subepicardial delayed hyperenhancement in the lateral and posterior walls correlating closely with the strain pattern obtained by 2D speckle tracking echocardiography. With a working diagnosis of acute myocarditis associated with acute tonsillitis, we prescribed antibiotics and nonsteroidal anti-inflammatory drugs. The patient’s clinical signs resolved along with normalization of serum creatine kinase (CK) levels, and the patient was discharged on the third day after admission. Learning points Acute myocarditis can mimic acute coronary syndromes.Conventional 2D echocardiography lacks specific features for detection of subtle regional wall motion abnormalities.2D speckle tracking expands the scope of echocardiography in identifying myocardial dysfunction derived from edema in acute myocarditis. PMID:27249814

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

    PubMed Central

    Lee, Jehoon; Sandhu, Romeil; Tannenbaum, Allen

    2013-01-01

    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

  15. 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.

  16. Structured light 3D tracking system for measuring motions in PET brain imaging

    NASA Astrophysics Data System (ADS)

    Olesen, Oline V.; Jørgensen, Morten R.; Paulsen, Rasmus R.; Højgaard, Liselotte; Roed, Bjarne; Larsen, Rasmus

    2010-02-01

    Patient motion during scanning deteriorates image quality, especially for high resolution PET scanners. A new proposal for a 3D head tracking system for motion correction in high resolution PET brain imaging is set up and demonstrated. A prototype tracking system based on structured light with a DLP projector and a CCD camera is set up on a model of the High Resolution Research Tomograph (HRRT). Methods to reconstruct 3D point clouds of simple surfaces based on phase-shifting interferometry (PSI) are demonstrated. The projector and camera are calibrated using a simple stereo vision procedure where the projector is treated as a camera. Additionally, the surface reconstructions are corrected for the non-linear projector output prior to image capture. The results are convincing and a first step toward a fully automated tracking system for measuring head motions in PET imaging.

  17. 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.

  18. 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.

  19. Application of three-dimensional speckle tracking echocardiography to assess left ventricular regional work using wall tension-regional area loop.

    PubMed

    Hioki, Ayana; Masuda, Kasumi; Asanuma, Toshihiko; Goto, Yoichi; Nakatani, Satoshi

    2015-05-15

    Three-dimensional (3-D) speckle tracking echocardiography allows us to track a change in regional endocardial surface area. The change of regional area during a cardiac cycle should be useful for assessing left ventricular regional work. We investigated the feasibility of assessing regional work, calculated as the area within the wall tension-regional area (T-A) loop using 3-D echocardiography. Three-dimensional full-volume images were acquired using 3-D echocardiography (Artida, Toshiba) at baseline and during brief occlusion of the left circumflex coronary artery in eight dogs. Wall tension was calculated according to Laplace's law for a spherical model. Area change ratio (in %) determined by area tracking was transformed into a change of regional area (in cm(2)) by a custom software. We calculated the area within the T-A loop (TAA) in the area under transient ischemia (risk area) and the remote area as regional work and validated the T-A loop method by comparing the global integral of TAA with the total work assessed by the pressure-volume loop. During coronary occlusion, regional work for the risk area significantly decreased (baseline vs. occlusion, 26.8 ± 10.7 vs. 18.4 ± 7.8 mmHg·cm(3); P < 0.05), whereas that for the remote area did not change. The global integral of TAA closely correlated with the total work assessed by the pressure-volume loop (r = 0.91, P < 0.0001). The wall T-A loop reflected regional dysfunction caused by myocardial ischemia. This analysis using 3-D speckle tracking echocardiography might be useful to quantify left ventricular regional work.

  20. Fusing inertial sensor data in an extended Kalman filter for 3D camera tracking.

    PubMed

    Erdem, Arif Tanju; Ercan, Ali Özer

    2015-02-01

    In a setup where camera measurements are used to estimate 3D egomotion in an extended Kalman filter (EKF) framework, it is well-known that inertial sensors (i.e., accelerometers and gyroscopes) are especially useful when the camera undergoes fast motion. Inertial sensor data can be fused at the EKF with the camera measurements in either the correction stage (as measurement inputs) or the prediction stage (as control inputs). In general, only one type of inertial sensor is employed in the EKF in the literature, or when both are employed they are both fused in the same stage. In this paper, we provide an extensive performance comparison of every possible combination of fusing accelerometer and gyroscope data as control or measurement inputs using the same data set collected at different motion speeds. In particular, we compare the performances of different approaches based on 3D pose errors, in addition to camera reprojection errors commonly found in the literature, which provides further insight into the strengths and weaknesses of different approaches. We show using both simulated and real data that it is always better to fuse both sensors in the measurement stage and that in particular, accelerometer helps more with the 3D position tracking accuracy, whereas gyroscope helps more with the 3D orientation tracking accuracy. We also propose a simulated data generation method, which is beneficial for the design and validation of tracking algorithms involving both camera and inertial measurement unit measurements in general.

  1. 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.

  2. Physiological basis in the assessment of myocardial mechanics using speckle-tracking echocardiography 2D. Part II.

    PubMed

    Mądry, Wojciech; Karolczak, Maciej Aleksander

    2016-09-01

    In this paper, the authors attempt to concisely present the anatomical and pathophysiological bases as well as the principles for echocardiographic evaluation of mechanical aspects of cardiac function based on speckle tracking method. This technique uses a phenomenon involving the formation of characteristic image units, referred to as speckles or acoustic markers, which are stable during cardiac cycle, on a two-dimensional echocardiographic picture. Changes in the position of these speckles throughout the cardiac cycle, which are monitored and analyzed semi-automatically by a computer system, reflect deformation of both, cardiac ventricle as a whole as well as its individual anatomical segments. The values of strain and the strain rate, as well as the range and velocity of the movement of these markers, which are in close relationship with multiple hemodynamic parameters, can be visualized as various types of charts - linear, two- and three-dimensional - as well as numerical values, enabling deeper insight into the mechanical and hemodynamic aspects of cardiac function in health and disease. The use of information obtained based on speckle tracking echocardiography allows to understand previously unclear mechanisms of physiological and pathophysiological processes. The first part of the study discusses the formation of a two-dimensional ultrasound image and the speckles, as well as the technical aspects of tracking their movement. The second part presents in more detail the methodology of speckle-tracking echocardiography, the characteristic abnormalities of cardiac mechanics presenting in different clinical entities, and the limitations related to given clinical and technical issues.

  3. Physiological basis in the assessment of myocardial mechanics using speckle-tracking echocardiography 2D. Part I.

    PubMed

    Mądry, Wojciech; Karolczak, Maciej Aleksander

    2016-06-01

    In this paper, the authors attempt to concisely present the anatomical and pathophysiological bases as well as the principles for echocardiographic evaluation of mechanical aspects of cardiac function based on speckle tracking method. This technique uses a phenomenon involving the formation of characteristic image units, referred to as speckles or acoustic markers, which are stable during cardiac cycle, on a two-dimensional echocardiographic picture. Changes in the position of these speckles throughout the cardiac cycle, which are monitored and analyzed semi-automatically by a computer system, reflect deformation of both, cardiac ventricle as a whole as well as its individual anatomical segments. The values of strain and the strain rate, as well as the range and velocity of the movement of these markers, which are in close relationship with multiple hemodynamic parameters, can be visualized as various types of charts - linear, two- and three-dimensional - as well as numerical values, enabling deeper insight into the mechanical and hemodynamic aspects of cardiac function in health and disease. The use of information obtained based on speckle tracking echocardiography allows to understand previously unclear mechanisms of physiological and pathophysiological processes. The first part of the study discusses the formation of a two-dimensional ultrasound image and the speckles, as well as the technical aspects of tracking their movement. The second part presents in more detail the methodology of speckle-tracking echocardiography, the characteristic abnormalities of cardiac mechanics presenting in different clinical entities, and the limitations related to given clinical and technical issues.

  4. 3D Orbital Tracking in a Modified Two-photon Microscope: An Application to the Tracking of Intracellular Vesicles

    PubMed Central

    Gratton, Enrico

    2014-01-01

    The objective of this video protocol is to discuss how to perform and analyze a three-dimensional fluorescent orbital particle tracking experiment using a modified two-photon microscope1. As opposed to conventional approaches (raster scan or wide field based on a stack of frames), the 3D orbital tracking allows to localize and follow with a high spatial (10 nm accuracy) and temporal resolution (50 Hz frequency response) the 3D displacement of a moving fluorescent particle on length-scales of hundreds of microns2. The method is based on a feedback algorithm that controls the hardware of a two-photon laser scanning microscope in order to perform a circular orbit around the object to be tracked: the feedback mechanism will maintain the fluorescent object in the center by controlling the displacement of the scanning beam3-5. To demonstrate the advantages of this technique, we followed a fast moving organelle, the lysosome, within a living cell6,7. Cells were plated according to standard protocols, and stained using a commercially lysosome dye. We discuss briefly the hardware configuration and in more detail the control software, to perform a 3D orbital tracking experiment inside living cells. We discuss in detail the parameters required in order to control the scanning microscope and enable the motion of the beam in a closed orbit around the particle. We conclude by demonstrating how this method can be effectively used to track the fast motion of a labeled lysosome along microtubules in 3D within a live cell. Lysosomes can move with speeds in the range of 0.4-0.5 µm/sec, typically displaying a directed motion along the microtubule network8. PMID:25350070

  5. 3D orbital tracking in a modified two-photon microscope: an application to the tracking of intracellular vesicles.

    PubMed

    Anzalone, Andrea; Annibale, Paolo; Gratton, Enrico

    2014-10-01

    The objective of this video protocol is to discuss how to perform and analyze a three-dimensional fluorescent orbital particle tracking experiment using a modified two-photon microscope(1). As opposed to conventional approaches (raster scan or wide field based on a stack of frames), the 3D orbital tracking allows to localize and follow with a high spatial (10 nm accuracy) and temporal resolution (50 Hz frequency response) the 3D displacement of a moving fluorescent particle on length-scales of hundreds of microns(2). The method is based on a feedback algorithm that controls the hardware of a two-photon laser scanning microscope in order to perform a circular orbit around the object to be tracked: the feedback mechanism will maintain the fluorescent object in the center by controlling the displacement of the scanning beam(3-5). To demonstrate the advantages of this technique, we followed a fast moving organelle, the lysosome, within a living cell(6,7). Cells were plated according to standard protocols, and stained using a commercially lysosome dye. We discuss briefly the hardware configuration and in more detail the control software, to perform a 3D orbital tracking experiment inside living cells. We discuss in detail the parameters required in order to control the scanning microscope and enable the motion of the beam in a closed orbit around the particle. We conclude by demonstrating how this method can be effectively used to track the fast motion of a labeled lysosome along microtubules in 3D within a live cell. Lysosomes can move with speeds in the range of 0.4-0.5 µm/sec, typically displaying a directed motion along the microtubule network(8).

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

    PubMed Central

    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

  7. 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

    2016-08-22

    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.

  8. 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.

  9. 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.

  10. 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.

  11. Full-field tracking and measuring of particle motion in capillary vessels by using time-varying laser speckle

    NASA Astrophysics Data System (ADS)

    Zhang, Luying; Wang, Bo; Wang, Yi

    2016-03-01

    We propose a random perturbation model to describe the variation of laser speckle patterns caused by moving particles in capillary vessels. When passing through probing volume, moving particles encode random perturbations into observed laser speckle patterns. We extract the perturbation envelopes of time-varying laser speckles for tracking the motion of single particle. And, the full-field transverse velocities of flowing particles are obtained by using cross-correlation between the perturbation envelopes. The proposed method is experimentally verified by the use of polymer-microsphere suspension in a glass capillary.

  12. Cooperative Wall-climbing Robots in 3D Environments for Surveillance and Target Tracking

    DTIC Science & Technology

    2009-02-08

    distribution of impeller vanes, volume of the chamber, and sealing effect , etc. Fig. 5 and 6 show some exemplary simulation results. In paper [11], we...Environments for Surveillance and Target Tracking 11 multiple nonholonomic mobile robots using Cartesian coordinates. Based on the special feature...gamma-ray or x-ray cargo inspection system. Three-dimensional (3D) measurements of the objects inside a cargo can be obtained by effectively

  13. 3D imaging of semiconductor colloid nanocrystals: on the way to nanodiagnostics of track membranes

    NASA Astrophysics Data System (ADS)

    Kulyk, S. I.; Eremchev, I. Y.; Gorshelev, A. A.; Naumov, A. V.; Zagorsky, D. L.; Kotova, S. P.; Volostnikov, V. G.; Vorontsov, E. N.

    2016-12-01

    The work concerns the feasibility of 3D optical diagnostic of porous media with subdifraction spatial resolution via epi-luminescence microscopy of single semiconductor colloid nanocrystals (quantum dots, QD) CdSe/ZnS used as emitting labels/nanoprobes. The nanoprecise reconstruction of axial coordinate is provided by double helix technique of point spread function transformation (DH-PSF). The results of QD localization in polycarbonate track membrane (TM) is presented.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Speckle tracking echocardiography detects uremic cardiomyopathy early and predicts cardiovascular mortality in ESRD.

    PubMed

    Kramann, Rafael; Erpenbeck, Johanna; Schneider, Rebekka K; Röhl, Anna B; Hein, Marc; Brandenburg, Vincent M; van Diepen, Merel; Dekker, Friedo; Marx, Nicolaus; Floege, Jürgen; Becker, Michael; Schlieper, Georg

    2014-10-01

    Cardiovascular mortality is high in ESRD, partly driven by sudden cardiac death and recurrent heart failure due to uremic cardiomyopathy. We investigated whether speckle-tracking echocardiography is superior to routine echocardiography in early detection of uremic cardiomyopathy in animal models and whether it predicts cardiovascular mortality in patients undergoing dialysis. Using speckle-tracking echocardiography in two rat models of uremic cardiomyopathy soon (4-6 weeks) after induction of kidney disease, we observed that global radial and circumferential strain parameters decreased significantly in both models compared with controls, whereas standard echocardiographic readouts, including fractional shortening and cardiac output, remained unchanged. Furthermore, strain parameters showed better correlations with histologic hallmarks of uremic cardiomyopathy. We then assessed echocardiographic and clinical characteristics in 171 dialysis patients. During the 2.5-year follow-up period, ejection fraction and various strain parameters were significant risk factors for cardiovascular mortality (primary end point) in a multivariate Cox model (ejection fraction hazard ratio [HR], 0.97 [95% confidence interval (95% CI), 0.95 to 0.99; P=0.012]; peak global longitudinal strain HR, 1.17 [95% CI, 1.07 to 1.28; P<0.001]; peak systolic and late diastolic longitudinal strain rates HRs, 4.7 [95% CI, 1.23 to 17.64; P=0.023] and 0.25 [95% CI, 0.08 to 0.79; P=0.02], respectively). Multivariate Cox regression analysis revealed circumferential early diastolic strain rate, among others, as an independent risk factor for all-cause mortality (secondary end point; HR, 0.43; 95% CI, 0.25 to 0.74; P=0.002). Together, these data support speckle tracking as a postprocessing echocardiographic technique to detect uremic cardiomyopathy and predict cardiovascular mortality in ESRD.

  19. 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.

  20. Coordination of gaze and hand movements for tracking and tracing in 3D.

    PubMed

    Gielen, Constantinus C A M; Dijkstra, Tjeerd M H; Roozen, Irene J; Welten, Joke

    2009-03-01

    In this study we have investigated movements in three-dimensional space. Since most studies have investigated planar movements (like ellipses, cloverleaf shapes and "figure eights") we have compared two generalizations of the two-thirds power law to three dimensions. In particular we have tested whether the two-thirds power law could be best described by tangential velocity and curvature in a plane (compatible with the idea of planar segmentation) or whether tangential velocity and curvature should be calculated in three dimensions. We defined total curvature in three dimensions as the square root of the sum of curvature squared and torsion squared. The results demonstrate that most of the variance is explained by tangential velocity and total curvature. This indicates that all three orthogonal components of movements in 3D are equally important and that movements are truly 3D and do not reflect a concatenation of 2D planar movement segments. In addition, we have studied the coordination of eye and hand movements in 3D by measuring binocular eye movements while subjects move the finger along a curved path. The results show that the directional component and finger position almost superimpose when subjects track a target moving in 3D. However, the vergence component of gaze leads finger position by about 250msec. For drawing (tracing) the path of a visible 3D shape, the directional component of gaze leads finger position by about 225msec, and the vergence component leads finger position by about 400msec. These results are compatible with the idea that gaze leads hand position during drawing movement to assist prediction and planning of hand position in 3D space.

  1. Evaluation of myocardial infarction size with three-dimensional speckle tracking echocardiography: a comparison with single photon emission computed tomography.

    PubMed

    Wang, Qiushuang; Zhang, Chunhong; Huang, Dangsheng; Zhang, Liwei; Yang, Feifei; An, Xiuzhi; Ouyang, Qiaohong; Zhang, Meiqing; Wang, Shuhua; Guo, Jiarui; Ji, Dongdong

    2015-12-01

    To assess whether global and regional myocardial strains from three-dimensional speckle tracking echocardiography (3D-STE) correlate with myocardial infarction size (MIS) detected by single photon emission computed tomography (SPECT). Fifty-seven patients with a history of ST-segment elevation myocardial infarction (MI) within 3-6 months were enrolled, alongside 24 healthy volunteers. Left ventricular (LV) global area strain, global longitudinal strain (GLS), global radial strain, global circumferential strain, left ventricular ejection fraction (LVEF) and wall motion score index (WMSI) were measured and compared with the corresponding SPECT-detected MISs. Patients were sub-grouped into massive MIS group (MIS ≥ 12%) and small MIS group (MIS < 12%). Myocardial strains of all the LV segments were compared with the corresponding MIS. Global myocardial strain parameters, LVEF and WMSI of the patients were significantly different from the control group (all P < 0.05) and correlated well with MISs, most significantly for GLS (r = 0.728, P < 0.01). Significant differences in myocardial strain parameters were found between the massive and small MIS groups (all P < 0.05). Receiver operating characteristic curve analysis indicated that GLS had a highest diagnostic value and when the cutoff was -13.8%, the area under the curve was 0.84, with the 70.6% sensitivity and 87.5% specificity. Significant differences of myocardial strain parameters were observed between segments with and without transmural MIs (P < 0.01). 3D-STE myocardial strain parameters evaluated LV global MIS, 3D GLS had the highest diagnostic value. It also preliminarily gauged the degree of ischemia and necrosis of regional myocardial segments.

  2. Analysis of thoracic aorta hemodynamics using 3D particle tracking velocimetry and computational fluid dynamics.

    PubMed

    Gallo, Diego; Gülan, Utku; Di Stefano, Antonietta; Ponzini, Raffaele; Lüthi, Beat; Holzner, Markus; Morbiducci, Umberto

    2014-09-22

    Parallel to the massive use of image-based computational hemodynamics to study the complex flow establishing in the human aorta, the need for suitable experimental techniques and ad hoc cases for the validation and benchmarking of numerical codes has grown more and more. Here we present a study where the 3D pulsatile flow in an anatomically realistic phantom of human ascending aorta is investigated both experimentally and computationally. The experimental study uses 3D particle tracking velocimetry (PTV) to characterize the flow field in vitro, while finite volume method is applied to numerically solve the governing equations of motion in the same domain, under the same conditions. Our findings show that there is an excellent agreement between computational and measured flow fields during the forward flow phase, while the agreement is poorer during the reverse flow phase. In conclusion, here we demonstrate that 3D PTV is very suitable for a detailed study of complex unsteady flows as in aorta and for validating computational models of aortic hemodynamics. In a future step, it will be possible to take advantage from the ability of 3D PTV to evaluate velocity fluctuations and, for this reason, to gain further knowledge on the process of transition to turbulence occurring in the thoracic aorta.

  3. 3-D Flow Field Diagnostics and Validation Studies using Stereoscopic Tracking Velocimetry

    NASA Technical Reports Server (NTRS)

    Cha, Soyoung Stephen; Ramachandran, Narayanan; Whitaker, Ann F. (Technical Monitor)

    2002-01-01

    The measurement of 3-D three-component velocity fields is of great importance in both ground and space experiments for understanding materials processing and fluid physics. Here, we present the investigation results of stereoscopic tracking velocimetry (STV) for measuring 3-D velocity fields. The effort includes diagnostic technology development, experimental velocity measurement, and comparison with analytical and numerical computation. The advantages of STV stems from the system simplicity for building compact hardware and in software efficiency for continual near-real-time process monitoring. It also has illumination flexibility for observing volumetric flow fields from arbitrary directions. STV is based on stereoscopic CCD observations of particles seeded in a flow. Neural networks are used for data analysis. The developed diagnostic tool is tested with a simple directional solidification apparatus using Succinonitrile. The 3-D velocity field in the liquid phase is measured and compared with results from detailed numerical computations. Our theoretical, numerical, and experimental effort has shown STV to be a viable candidate for reliably quantifying the 3-D flow field in materials processing and fluids experiments.

  4. The CT-PPS tracking system with 3D pixel detectors

    NASA Astrophysics Data System (ADS)

    Ravera, F.

    2016-11-01

    The CMS-TOTEM Precision Proton Spectrometer (CT-PPS) detector will be installed in Roman pots (RP) positioned on either side of CMS, at about 210 m from the interaction point. This detector will measure leading protons, allowing detailed studies of diffractive physics and central exclusive production in standard LHC running conditions. An essential component of the CT-PPS apparatus is the tracking system, which consists of two detector stations per arm equipped with six 3D silicon pixel-sensor modules, each read out by six PSI46dig chips. The front-end electronics has been designed to fulfill the mechanical constraints of the RP and to be compatible as much as possible with the readout chain of the CMS pixel detector. The tracking system is currently under construction and will be installed by the end of 2016. In this contribution the final design and the expected performance of the CT-PPS tracking system is presented. A summary of the studies performed, before and after irradiation, on the 3D detectors produced for CT-PPS is given.

  5. Experimental analysis of mechanical response of stabilized occipitocervical junction by 3D mark tracking technique

    NASA Astrophysics Data System (ADS)

    Germaneau, A.; Doumalin, P.; Dupré, J. C.; Brèque, C.; Brémand, F.; D'Houtaud, S.; Rigoard, P.

    2010-06-01

    This study is about a biomechanical comparison of some stabilization solutions for the occipitocervical junction. Four kinds of occipito-cervical fixations are analysed in this work: lateral plates fixed by two kinds of screws, lateral plates fixed by hooks and median plate. To study mechanical rigidity of each one, tests have been performed on human skulls by applying loadings and by studying mechanical response of fixations and bone. For this experimental analysis, a specific setup has been developed to impose a load corresponding to the flexion-extension physiological movements. 3D mark tracking technique is employed to measure 3D displacement fields on the bone and on the fixations. Observations of displacement evolution on the bone according to the fixation show different rigidities given by each solution.

  6. Two-Dimensional Speckle Tracking of the Fetal Heart: A Practical Step-by-Step Approach for the Fetal Sonologist.

    PubMed

    DeVore, Greggory R; Polanco, Bardo; Satou, Gary; Sklansky, Mark

    2016-08-01

    Various approaches to 2-dimensional speckle tracking have been used to evaluate left ventricular function and deformation in the fetus, child, and adult. In 2015, because of differences in imaging devices and analytical programs, the cardiology community published a consensus document proposing standards for pediatric/adult deformation imaging using 2-dimensional speckle tracking. The understanding and application of deformation imaging in the fetus have been limited by a lack of uniform software, terminology, techniques, and display. This article provides a practical, step-by-step approach for deformation analysis of the fetal heart using offline software that is independent of specific ultrasound vendors.

  7. 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.

  8. Swimming Behavior of Pseudomonas aeruginosa Studied by Holographic 3D Tracking

    PubMed Central

    Vater, Svenja M.; Weiße, Sebastian; Maleschlijski, Stojan; Lotz, Carmen; Koschitzki, Florian; Schwartz, Thomas; Obst, Ursula; Rosenhahn, Axel

    2014-01-01

    Holographic 3D tracking was applied to record and analyze the swimming behavior of Pseudomonas aeruginosa. The obtained trajectories allow to qualitatively and quantitatively analyze the free swimming behavior of the bacterium. This can be classified into five distinct swimming patterns. In addition to the previously reported smooth and oscillatory swimming motions, three additional patterns are distinguished. We show that Pseudomonas aeruginosa performs helical movements which were so far only described for larger microorganisms. Occurrence of the swimming patterns was determined and transitions between the patterns were analyzed. PMID:24498187

  9. 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.

  10. A portable instrument for 3-D dynamic robot measurements using triangulation and laser tracking

    SciTech Connect

    Mayer, J.R.R. . Mechanical Engineering Dept.); Parker, G.A. . Dept. of Mechanical Engineering)

    1994-08-01

    The paper describes the development and validation of a 3-D measurement instrument capable of determining the static and dynamic performance of industrial robots to ISO standards. Using two laser beams to track an optical target attached to the robot end-effector, the target position coordinates may be estimated, relative to the instrument coordinate frame, to a high accuracy using triangulation principles. The effect of variations in the instrument geometry from the nominal model is evaluated through a kinematic model of the tracking head. Significant improvements of the measurement accuracy are then obtained by a simple adjustment of the main parameters. Extensive experimental test results are included to demonstrate the instrument performance. Finally typical static and dynamic measurement results for an industrial robot are presented to illustrate the effectiveness and usefulness of the instrument.

  11. Passive markers for tracking surgical instruments in real-time 3-D ultrasound imaging.

    PubMed

    Stoll, Jeffrey; Ren, Hongliang; Dupont, Pierre E

    2012-03-01

    A family of passive echogenic markers is presented by which the position and orientation of a surgical instrument can be determined in a 3-D ultrasound volume, using simple image processing. Markers are attached near the distal end of the instrument so that they appear in the ultrasound volume along with the instrument tip. They are detected and measured within the ultrasound image, thus requiring no external tracking device. This approach facilitates imaging instruments and tissue simultaneously in ultrasound-guided interventions. Marker-based estimates of instrument pose can be used in augmented reality displays or for image-based servoing. Design principles for marker shapes are presented that ensure imaging system and measurement uniqueness constraints are met. An error analysis is included that can be used to guide marker design and which also establishes a lower bound on measurement uncertainty. Finally, examples of marker measurement and tracking algorithms are presented along with experimental validation of the concepts.

  12. Adaptive Kalman snake for semi-autonomous 3D vessel tracking.

    PubMed

    Lee, Sang-Hoon; Lee, Sanghoon

    2015-10-01

    In this paper, we propose a robust semi-autonomous algorithm for 3D vessel segmentation and tracking based on an active contour model and a Kalman filter. For each computed tomography angiography (CTA) slice, we use the active contour model to segment the vessel boundary and the Kalman filter to track position and shape variations of the vessel boundary between slices. For successful segmentation via active contour, we select an adequate number of initial points from the contour of the first slice. The points are set manually by user input for the first slice. For the remaining slices, the initial contour position is estimated autonomously based on segmentation results of the previous slice. To obtain refined segmentation results, an adaptive control spacing algorithm is introduced into the active contour model. Moreover, a block search-based initial contour estimation procedure is proposed to ensure that the initial contour of each slice can be near the vessel boundary. Experiments were performed on synthetic and real chest CTA images. Compared with the well-known Chan-Vese (CV) model, the proposed algorithm exhibited better performance in segmentation and tracking. In particular, receiver operating characteristic analysis on the synthetic and real CTA images demonstrated the time efficiency and tracking robustness of the proposed model. In terms of computational time redundancy, processing time can be effectively reduced by approximately 20%.

  13. 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.

  14. 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.

  15. 3D tracking the Brownian motion of colloidal particles using digital holographic microscopy and joint reconstruction.

    PubMed

    Verrier, Nicolas; Fournier, Corinne; Fournel, Thierry

    2015-06-01

    In-line digital holography is a valuable tool for sizing, locating, and tracking micro- or nano-objects in a volume. When a parametric imaging model is available, inverse problem approaches provide a straightforward estimate of the object parameters by fitting data with the model, thereby allowing accurate reconstruction. As recently proposed and demonstrated, combining pixel super-resolution techniques with inverse problem approaches improves the estimation of particle size and 3D position. Here, we demonstrate the accurate tracking of colloidal particles in Brownian motion. Particle size and 3D position are jointly optimized from video holograms acquired with a digital holographic microscopy setup based on a low-end microscope objective (×20, NA 0.5). Exploiting information redundancy makes it possible to characterize particles with a standard deviation of 15 nm in size and a theoretical resolution of 2×2×5  nm3 for position under additive white Gaussian noise assumption.

  16. Designing a high accuracy 3D auto stereoscopic eye tracking display, using a common LCD monitor

    NASA Astrophysics Data System (ADS)

    Taherkhani, Reza; Kia, Mohammad

    2012-09-01

    This paper describes the design and building of a low cost and practical stereoscopic display that does not need to wear special glasses, and uses eye tracking to give a large degree of freedom to viewer (or viewer's) movement while displaying the minimum amount of information. The parallax barrier technique is employed to turn a LCD into an auto-stereoscopic display. The stereo image pair is screened on the usual liquid crystal display simultaneously but in different columns of pixels. Controlling of the display in red-green-blue sub pixels increases the accuracy of light projecting direction to less than 2 degrees without losing too much LCD's resolution and an eye-tracking system determines the correct angle to project the images along the viewer's eye pupils and an image processing system puts the 3D images data in correct R-G-B sub pixels. 1.6 degree of light direction controlling achieved in practice. The 3D monitor is just made by applying some simple optical materials on a usual LCD display with normal resolution. [Figure not available: see fulltext.

  17. Nonintrusive viewpoint tracking for 3D for perception in smart video conference

    NASA Astrophysics Data System (ADS)

    Desurmont, Xavier; Martinez-Ponte, Isabel; Meessen, Jerome; Delaigle, Jean-François

    2006-02-01

    Globalisation of people's interaction in the industrial world and ecological cost of transport make video-conference an interesting solution for collaborative work. However, the lack of immersive perception makes video-conference not appealing. TIFANIS tele-immersion system was conceived to let users interact as if they were physically together. In this paper, we focus on an important feature of the immersive system: the automatic tracking of the user's point of view in order to render correctly in his display the scene from the ther site. Viewpoint information has to be computed in a very short time and the detection system should be no intrusive, otherwise it would become cumbersome for the user, i.e. he would lose the feeling of "being there". The viewpoint detection system consists of several modules. First, an analysis module identifies and follows regions of interest (ROI) where faces are detected. We will show the cooperative approach between spatial detection and temporal tracking. Secondly, an eye detector finds the position of the eyes within faces. Then, the 3D positions of the eyes are deduced using stereoscopic images from a binocular camera. Finally, the 3D scene is rendered in real-time according to the new point of view.

  18. Comparison of 2D and 3D modeled tumor motion estimation/prediction for dynamic tumor tracking during arc radiotherapy.

    PubMed

    Liu, Wu; Ma, Xiangyu; Yan, Huagang; Chen, Zhe; Nath, Ravinder; Li, Haiyun

    2017-03-06

    Many real-time imaging techniques have been developed to localize the target in 3D space or in 2D beam's eye view (BEV) plane for intrafraction motion tracking in radiation therapy. With tracking system latency, 3D-modeled method is expected to be more accurate even in terms of 2D BEV tracking error. No quantitative analysis, however, has been reported. In this study, we simulated co-planar arc deliveries using respiratory motion data acquired from 42 patients to quantitatively compare the accuracy between 2D BEV and 3D-modeled tracking in arc therapy and determine whether 3D information is needed for motion tracking. We used our previously developed low kV dose adaptive MV-kV imaging and motion compensation framework as a representative of 3D-modeled methods. It optimizes the balance between additional kV imaging dose and 3D tracking accuracy and solves the MLC blockage issue. With simulated Gaussian marker detection errors (zero mean and 0.39 mm standard deviation) and ~155/310/460 ms tracking system latencies, the mean percentage of time that the target moved >2 mm from the predicted 2D BEV position are 1.1%/4.0%/7.8% and 1.3%/5.8%/11.6% for 3D-modeled and 2D-only tracking, respectively. The corresponding average BEV RMS errors are 0.67/0.90/1.13 mm and 0.79/1.10/1.37 mm. Compared to the 2D method, the 3D method reduced the average RMS unresolved motion along the beam direction from ~3 mm to ~1 mm, resulting on average only <1% dosimetric advantage in the depth direction. Only for a small fraction of the patients, when tracking latency is long, the 3D-modeled method showed significant improvement of BEV tracking accuracy, indicating potential dosimetric advantage. However, if the tracking latency is short (~150 ms or less), those improvements are limited. Therefore, 2D BEV tracking has sufficient targeting accuracy for most clinical cases. The 3D technique is, however, still important in solving the MLC blockage problem during 2D BEV tracking.

  19. Robust object tracking techniques for vision-based 3D motion analysis applications

    NASA Astrophysics Data System (ADS)

    Knyaz, Vladimir A.; Zheltov, Sergey Y.; Vishnyakov, Boris V.

    2016-04-01

    Automated and accurate spatial motion capturing of an object is necessary for a wide variety of applications including industry and science, virtual reality and movie, medicine and sports. For the most part of applications a reliability and an accuracy of the data obtained as well as convenience for a user are the main characteristics defining the quality of the motion capture system. Among the existing systems for 3D data acquisition, based on different physical principles (accelerometry, magnetometry, time-of-flight, vision-based), optical motion capture systems have a set of advantages such as high speed of acquisition, potential for high accuracy and automation based on advanced image processing algorithms. For vision-based motion capture accurate and robust object features detecting and tracking through the video sequence are the key elements along with a level of automation of capturing process. So for providing high accuracy of obtained spatial data the developed vision-based motion capture system "Mosca" is based on photogrammetric principles of 3D measurements and supports high speed image acquisition in synchronized mode. It includes from 2 to 4 technical vision cameras for capturing video sequences of object motion. The original camera calibration and external orientation procedures provide the basis for high accuracy of 3D measurements. A set of algorithms as for detecting, identifying and tracking of similar targets, so for marker-less object motion capture is developed and tested. The results of algorithms' evaluation show high robustness and high reliability for various motion analysis tasks in technical and biomechanics applications.

  20. A Hidden Markov Model for 3D Catheter Tip Tracking with 2D X-ray Catheterization Sequence and 3D Rotational Angiography.

    PubMed

    Ambrosini, Pierre; Smal, Ihor; Ruijters, Daniel; Niessen, Wiro; Moelker, Adriaan; van Walsum, Theo

    2016-11-07

    In minimal invasive image guided catheterization procedures, physicians require information of the catheter position with respect to the patient's vasculature. However, in fluoroscopic images, visualization of the vasculature requires toxic contrast agent. Static vasculature roadmapping, which can reduce the usage of iodine contrast, is hampered by the breathing motion in abdominal catheterization. In this paper, we propose a method to track the catheter tip inside the patient's 3D vessel tree using intra-operative single-plane 2D X-ray image sequences and a peri-operative 3D rotational angiography (3DRA). The method is based on a hidden Markov model (HMM) where states of the model are the possible positions of the catheter tip inside the 3D vessel tree. The transitions from state to state model the probabilities for the catheter tip to move from one position to another. The HMM is updated following the observation scores, based on the registration between the 2D catheter centerline extracted from the 2D X-ray image, and the 2D projection of 3D vessel tree centerline extracted from the 3DRA. The method is extensively evaluated on simulated and clinical datasets acquired during liver abdominal catheterization. The evaluations show a median 3D tip tracking error of 2.3 mm with optimal settings in simulated data. The registered vessels close to the tip have a median distance error of 4.7 mm with angiographic data and optimal settings. Such accuracy is sufficient to help the physicians with an up-to-date roadmapping. The method tracks in real-time the catheter tip and enables roadmapping during catheterization procedures.

  1. Physiological basis in the assessment of myocardial mechanics using speckle-tracking echocardiography 2D. Part I

    PubMed Central

    Karolczak, Maciej Aleksander

    2016-01-01

    In this paper, the authors attempt to concisely present the anatomical and pathophysiological bases as well as the principles for echocardiographic evaluation of mechanical aspects of cardiac function based on speckle tracking method. This technique uses a phenomenon involving the formation of characteristic image units, referred to as speckles or acoustic markers, which are stable during cardiac cycle, on a two-dimensional echocardiographic picture. Changes in the position of these speckles throughout the cardiac cycle, which are monitored and analyzed semi-automatically by a computer system, reflect deformation of both, cardiac ventricle as a whole as well as its individual anatomical segments. The values of strain and the strain rate, as well as the range and velocity of the movement of these markers, which are in close relationship with multiple hemodynamic parameters, can be visualized as various types of charts – linear, two- and three-dimensional – as well as numerical values, enabling deeper insight into the mechanical and hemodynamic aspects of cardiac function in health and disease. The use of information obtained based on speckle tracking echocardiography allows to understand previously unclear mechanisms of physiological and pathophysiological processes. The first part of the study discusses the formation of a two-dimensional ultrasound image and the speckles, as well as the technical aspects of tracking their movement. The second part presents in more detail the methodology of speckle-tracking echocardiography, the characteristic abnormalities of cardiac mechanics presenting in different clinical entities, and the limitations related to given clinical and technical issues. PMID:27446598

  2. Physiological basis in the assessment of myocardial mechanics using speckle-tracking echocardiography 2D. Part II

    PubMed Central

    Karolczak, Maciej Aleksander

    2016-01-01

    In this paper, the authors attempt to concisely present the anatomical and pathophysiological bases as well as the principles for echocardiographic evaluation of mechanical aspects of cardiac function based on speckle tracking method. This technique uses a phenomenon involving the formation of characteristic image units, referred to as speckles or acoustic markers, which are stable during cardiac cycle, on a two-dimensional echocardiographic picture. Changes in the position of these speckles throughout the cardiac cycle, which are monitored and analyzed semi-automatically by a computer system, reflect deformation of both, cardiac ventricle as a whole as well as its individual anatomical segments. The values of strain and the strain rate, as well as the range and velocity of the movement of these markers, which are in close relationship with multiple hemodynamic parameters, can be visualized as various types of charts – linear, two- and three-dimensional – as well as numerical values, enabling deeper insight into the mechanical and hemodynamic aspects of cardiac function in health and disease. The use of information obtained based on speckle tracking echocardiography allows to understand previously unclear mechanisms of physiological and pathophysiological processes. The first part of the study discusses the formation of a two-dimensional ultrasound image and the speckles, as well as the technical aspects of tracking their movement. The second part presents in more detail the methodology of speckle-tracking echocardiography, the characteristic abnormalities of cardiac mechanics presenting in different clinical entities, and the limitations related to given clinical and technical issues. PMID:27679734

  3. Three-dimensional speckle tracking longitudinal strain is related to myocardial fibrosis determined by late-gadolinium enhancement.

    PubMed

    Spartera, Marco; Damascelli, Anna; Mozes, Ferenc; De Cobelli, Francesco; La Canna, Giovanni

    2017-03-15

    Three-dimensional (3D) speckle tracking echocardiography (STE) is a reliable clinical tool for accurate measurements of left ventricular (LV) volumes and ejection fraction (EF). In this prospective study, we sought to identify an association between 3DSTE longitudinal strain abnormalities and areas of late gadolinium enhancement (LGE). In 50 patients (52 ± 18.5 years old) referred to our hospital for clinically indicated CMR, 3D full-volume trans-thoracic acquisitions on apical views were performed within 1 h of CMR, in order to obtain LV volumes and ejection fraction as well as global and segmental peak systolic longitudinal strain. Relative amount of fibrosis was defined based on LGE CMR with grey-scale threshold of 5 standard deviations above the mean signal intensity of the normal remote myocardium. We found a moderate positive correlation between global longitudinal strain (GLS) by 3DSTE and LGE proportion (r = 0.465, p = 0.001). The area under the receiver operating characteristic curve was 0.79. In addition, abnormal GLS could detect LGE-determined myocardial fibrosis with a sensitivity of 84.6%, a specificity of 84.8%, a positive predictive value of 69% and negative predictive value of 93%, considering an optimal GLS cut-off value of - 15.25%. Regarding 3DSTE capacity of localizing segmental LGE involvement, about 70% of LGE-positive segments presented a concomitant longitudinal strain reduction. This prospective study shows that 3DSTE longitudinal deformation is moderately associated with the extent of myocardial fibrosis, with a promising potential role in ruling out prognostically relevant fibrosis as detected by LGE.

  4. 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.

  5. Segmentation and tracking of adherens junctions in 3D for the analysis of epithelial tissue morphogenesis.

    PubMed

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

    2015-04-01

    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).

  6. 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

  7. Simulations of Coalescence and Breakup of Interfaces Using a 3D Front-tracking Method

    NASA Astrophysics Data System (ADS)

    Lu, Jiacai; Tryggvason, Gretar

    2015-11-01

    Direct Numerical Simulations (DNS) of complex multiphase flows with coalescing and breaking-up of interfaces are conducted using a 3D front-tracking method. Front-tracking method has been successfully used in DNS of turbulent channel bubbly flows and many other multiphase flows, but as the void fraction increases changes in the interface topology, though coalescence and breakup, become more common and have to be accounted for. Topology changes have often been identified as a challenge for front tracking, where the interface is represented using a triangular mesh, but here we present an efficient algorithm to change the topology of triangular elements of interfaces. In the current implementation we have not included any small-scale attractive forces so thin films coalesce either at prescribed times or when their thickness reaches a given value. Simulations of the collisions of two drops and comparisons with experimental results have been used to validate the algorithm but the main applications have been to flow regime transitions in gas-liquid flows in pressure driven channel flows. The evolution of flow, including flow rate, wall shear, projected interface areas, pseudo-turbulence, and the average size of the various flow structures, is examined as the topology of the interface changes through coalescence and breakup. Research supported by DOE (CASL).

  8. High-accuracy and real-time 3D positioning, tracking system for medical imaging applications based on 3D digital image correlation

    NASA Astrophysics Data System (ADS)

    Xue, Yuan; Cheng, Teng; Xu, Xiaohai; Gao, Zeren; Li, Qianqian; Liu, Xiaojing; Wang, Xing; Song, Rui; Ju, Xiangyang; Zhang, Qingchuan

    2017-01-01

    This paper presents a system for positioning markers and tracking the pose of a rigid object with 6 degrees of freedom in real-time using 3D digital image correlation, with two examples for medical imaging applications. Traditional DIC method was improved to meet the requirements of the real-time by simplifying the computations of integral pixel search. Experiments were carried out and the results indicated that the new method improved the computational efficiency by about 4-10 times in comparison with the traditional DIC method. The system was aimed for orthognathic surgery navigation in order to track the maxilla segment after LeFort I osteotomy. Experiments showed noise for the static point was at the level of 10-3 mm and the measurement accuracy was 0.009 mm. The system was demonstrated on skin surface shape evaluation of a hand for finger stretching exercises, which indicated a great potential on tracking muscle and skin movements.

  9. Application of 3d-ptv To Track Particle Moving Inside Heterogeneous Porous Media

    NASA Astrophysics Data System (ADS)

    Cenedese, A.; Cushman, J. H.; Moroni, M.

    There exist a number of imaging-based measurement techniques for determining 3D velocity fields in an observation volume. Among these are: a) scanning techniques (Guezennec et al. 1994, Moroni and Cushman, 2001); b) holographic techniques (Hin- sch and Hinrichs 1996); c) defocusing techniques (Willert and Gharib 1992); d) stereo- scopic techniques (Maas et al. 1993, Kasagi and Nishino 1990). We have focused our attention on 3D-PTV which is an experimental technique based on reconstructing 3D trajectories of reflecting tracer particles through a stereoscopic recording of image se- quences. Coordinates are determined first and then trajectories are defined. 3D-PTV requires the operator to light a volume of the test section as opposed to 2D techniques that require a light sheet. Stereoscopic methods share the following basic steps (Pa- pantoniou, 1990): a) stereoscopic calibrated imaging and recording of a suitably illu- minated particle flow; b) subsequent photogrammetric analysis of the resulting images to derive the instantaneous 3-D particle positions and c) tracking of the 3-D coordinate sets in time to derive the tracer trajectories. The ideal setup for obtaining highly accu- rate trajectories requires the cameras to be mounted with the distance between them equal to the distance to the center of the measurement volume (with three cameras this requires a hexagonal cell). But the camera arrangement is usually a compromise between ideal geometrical conditions for a homogeneous distribution of accuracies in the measuring volume and practical restrictions associated with the experiment. The position of the cameras in object space (exterior orientation) and the parameters of each camera (interior orientation) are needed to reconstruct the 3D objects. These pa- rameters can be calculated simultaneously in a so-called "bundle adjustment" or by pre-calibration. A matched index (of refraction) porous medium heterogeneous at the bench scale has been constructed by filling

  10. Two-dimensional speckle tracking cardiac mechanics and constrictive pericarditis: systematic review.

    PubMed

    Madeira, Marta; Teixeira, Rogério; Costa, Marco; Gonçalves, Lino; Klein, Allan L

    2016-10-01

    Transthoracic echocardiography has a pivotal role in the diagnosis of constrictive pericarditis (CP). In addition to the classic M-mode, two-dimensional and Doppler indices, newer methodologies designed to evaluate myocardial mechanics, such as two-dimensional speckle tracking echocardiography (2DSTE), provide additional diagnostic and clinical information in the context of CP. Research has demonstrated that cardiac mechanics can improve echocardiographic diagnostic accuracy of CP and aid in differentiating between constrictive and restrictive ventricular physiology. 2DSTE can also be used to assess the success of pericardiectomy and its impact on atrial and ventricular mechanics. In the course of this review, we describe cardiac mechanics in patients with CP and summarize the influence of pericardiectomy on atrial and ventricular mechanics assessed using 2DSTE.

  11. Left ventricular hypertrophy or storage disease? the incremental value of speckle tracking strain bull's-eye.

    PubMed

    D'Andrea, Antonello; Radmilovic, Juri; Ballo, Piercarlo; Mele, Donato; Agricola, Eustachio; Cameli, Matteo; Rossi, Andrea; Esposito, Roberta; Novo, Giuseppina; Mondillo, Sergio; Montisci, Roberta; Gallina, Sabina; Bossone, Eduardo; Galderisi, Maurizio

    2017-03-19

    Left ventricular hypertrophy (LVH) develops in response to a variety of physical, genetic, and biochemical stimuli and represents the early stage of ventricular remodeling. In patients with LVH, subclinical left ventricular (LV) dysfunction despite normal ejection fraction (EF) may be present before the onset of symptoms, which portends a dismal prognosis. Strain measurement with two-dimensional speckle tracking echocardiography (STE) represents a highly reproducible and accurate alternative to LVEF determination. The present review focuses on current available evidence that supports the incremental value of STE in the diagnostic and prognostic workup of LVH. When assessing the components of LV contraction, STE has an incremental value in differentiating between primary and secondary LVH and in the differential diagnosis with storage diseases. In addition, STE provides unique information for the stratification of patients with LVH, enabling to detect intrinsic myocardial dysfunction before LVEF reduction.

  12. 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

  13. 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.

  14. Defragmented image based autostereoscopic 3D displays with dynamic eye tracking

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Kyu; Yoon, Ki-Hyuk; Yoon, Seon Kyu; Ju, Heongkyu

    2015-12-01

    We studied defragmented image based autostereoscopic 3D displays with dynamic eye tracking. Specifically, we examined the impact of parallax barrier (PB) angular orientation on their image quality. The 3D display system required fine adjustment of PB angular orientation with respect to a display panel. This was critical for both image color balancing and minimizing image resolution mismatch between horizontal and vertical directions. For evaluating uniformity of image brightness, we applied optical ray tracing simulations. The simulations took effects of PB orientation misalignment into account. The simulation results were then compared with recorded experimental data. Our optimal simulated system produced significantly enhanced image uniformity at around sweet spots in viewing zones. However this was contradicted by real experimental results. We offer quantitative treatment of illuminance uniformity of view images to estimate misalignment of PB orientation, which could account for brightness non-uniformity observed experimentally. Our study also shows that slight imperfection in the adjustment of PB orientation due to practical restrictions of adjustment accuracy can induce substantial non-uniformity of view images' brightness. We find that image brightness non-uniformity critically depends on misalignment of PB angular orientation, for example, as slight as ≤ 0.01 ° in our system. This reveals that reducing misalignment of PB angular orientation from the order of 10-2 to 10-3 degrees can greatly improve the brightness uniformity.

  15. Using an automated 3D-tracking system to record individual and shoals of adult zebrafish.

    PubMed

    Maaswinkel, Hans; Zhu, Liqun; Weng, Wei

    2013-12-05

    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.

  16. 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.

  17. 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.

  18. 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.

  19. Real-time 3D motion tracking for small animal brain PET

    NASA Astrophysics Data System (ADS)

    Kyme, A. Z.; Zhou, V. W.; Meikle, S. R.; Fulton, R. R.

    2008-05-01

    High-resolution positron emission tomography (PET) imaging of conscious, unrestrained laboratory animals presents many challenges. Some form of motion correction will normally be necessary to avoid motion artefacts in the reconstruction. The aim of the current work was to develop and evaluate a motion tracking system potentially suitable for use in small animal PET. This system is based on the commercially available stereo-optical MicronTracker S60 which we have integrated with a Siemens Focus-220 microPET scanner. We present measured performance limits of the tracker and the technical details of our implementation, including calibration and synchronization of the system. A phantom study demonstrating motion tracking and correction was also performed. The system can be calibrated with sub-millimetre accuracy, and small lightweight markers can be constructed to provide accurate 3D motion data. A marked reduction in motion artefacts was demonstrated in the phantom study. The techniques and results described here represent a step towards a practical method for rigid-body motion correction in small animal PET. There is scope to achieve further improvements in the accuracy of synchronization and pose measurements in future work.

  20. Infrared tomographic PIV and 3D motion tracking system applied to aquatic predator-prey interaction

    NASA Astrophysics Data System (ADS)

    Adhikari, Deepak; Longmire, Ellen K.

    2013-02-01

    Infrared tomographic PIV and 3D motion tracking are combined to measure evolving volumetric velocity fields and organism trajectories during aquatic predator-prey interactions. The technique was used to study zebrafish foraging on both non-evasive and evasive prey species. Measurement volumes of 22.5 mm × 10.5 mm × 12 mm were reconstructed from images captured on a set of four high-speed cameras. To obtain accurate fluid velocity vectors within each volume, fish were first masked out using an automated visual hull method. Fish and prey locations were identified independently from the same image sets and tracked separately within the measurement volume. Experiments demonstrated that fish were not influenced by the infrared laser illumination or the tracer particles. Results showed that the zebrafish used different strategies, suction and ram feeding, for successful capture of non-evasive and evasive prey, respectively. The two strategies yielded different variations in fluid velocity between the fish mouth and the prey. In general, the results suggest that the local flow field, the direction of prey locomotion with respect to the predator and the relative accelerations and speeds of the predator and prey may all be significant in determining predation success.

  1. Evaluation and comparison of current biopsy needle localization and tracking methods using 3D ultrasound.

    PubMed

    Zhao, Yue; Shen, Yi; Bernard, Adeline; Cachard, Christian; Liebgott, Hervé

    2017-01-01

    This article compares four different biopsy needle localization algorithms in both 3D and 4D situations to evaluate their accuracy and execution time. The localization algorithms were: Principle component analysis (PCA), random Hough transform (RHT), parallel integral projection (PIP) and ROI-RK (ROI based RANSAC and Kalman filter). To enhance the contrast of the biopsy needle and background tissue, a line filtering pre-processing step was implemented. To make the PCA, RHT and PIP algorithms comparable with the ROI-RK method, a region of interest (ROI) strategy was added. Simulated and ex-vivo data were used to evaluate the performance of the different biopsy needle localization algorithms. The resolutions of the sectorial and cylindrical volumes were 0.3mm×0.4mm×0.6mmand0.1mm×0.1mm×0.2mm (axial×lateral×azimuthal) respectively. In so far as the simulation and experimental results show, the ROI-RK method successfully located and tracked the biopsy needle in both 3D and 4D situations. The tip localization error was within 1.5mm and the axis accuracy was within 1.6mm. To the best of our knowledge, considering both localization accuracy and execution time, the ROI-RK was the most stable and time-saving method. Normally, accuracy comes at the expense of time. However, the ROI-RK method was able to locate the biopsy needle with high accuracy in real time, which makes it a promising method for clinical applications.

  2. 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.

  3. Automated 3D motion tracking using Gabor filter bank, robust point matching, and deformable models.

    PubMed

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

    2010-01-01

    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

  4. Evaluation of myocardial deformation in patients with Kawasaki disease using speckle-tracking echocardiography during mid-term follow-up.

    PubMed

    Dedeoglu, Reyhan; Barut, Kenan; Oztunc, Funda; Atik, Sezen; Adrovic, Amra; Sahin, Sezgin; Cengiz, Dicle; Kasapcopur, Ozgur

    2017-04-05

    Speckle-tracking echocardiography is a recently developed technique for the evaluation of myocardial deformation or strain. Our objective was to examine strain through a mid-term follow-up of patients with Kawasaki disease.

  5. 3-D geometry calibration and markerless electromagnetic tracking with a mobile C-arm

    NASA Astrophysics Data System (ADS)

    Cheryauka, Arvi; Barrett, Johnny; Wang, Zhonghua; Litvin, Andrew; Hamadeh, Ali; Beaudet, Daniel

    2007-03-01

    The design of mobile X-ray C-arm equipment with image tomography and surgical guidance capabilities involves the retrieval of repeatable gantry positioning in three-dimensional space. Geometry misrepresentations can cause degradation of the reconstruction results with the appearance of blurred edges, image artifacts, and even false structures. It may also amplify surgical instrument tracking errors leading to improper implant placement. In our prior publications we have proposed a C-arm 3D positioner calibration method comprising separate intrinsic and extrinsic geometry calibration steps. Following this approach, in the present paper, we extend the intrinsic geometry calibration of C-gantry beyond angular positions in the orbital plane into angular positions on a unit sphere of isocentric rotation. Our method makes deployment of markerless interventional tool guidance with use of high-resolution fluoro images and electromagnetic tracking feasible at any angular position of the tube-detector assembly. Variations of the intrinsic parameters associated with C-arm motion are measured off-line as functions of orbital and lateral angles. The proposed calibration procedure provides better accuracy, and prevents unnecessary workflow steps for surgical navigation applications. With a slight modification, the Misalignment phantom, a tool for intrinsic geometry calibration, is also utilized to obtain an accurate 'image-to-sensor' mapping. We show simulation results, image quality and navigation accuracy estimates, and feasibility data acquired with the prototype system. The experimental results show the potential of high-resolution CT imaging (voxel size below 0.5 mm) and confident navigation in an interventional surgery setting with a mobile C-arm.

  6. Left atrial dysfunction detected by speckle tracking in patients with systemic sclerosis

    PubMed Central

    2014-01-01

    Background Cardiac involvement is a relevant clinical finding in systemic sclerosis (SSc) and is associated with poor prognosis. Left atrial (LA) remodeling and/or dysfunction can be an early sign of diastolic dysfunction. Two-dimensional speckle tracking echocardiography (STE) is a novel and promising tool for detecting very early changes in LA myocardial performance. Aim To assess whether STE strain parameters may detect early alterations in LA function in SSc patients. Methods Forty-two SSc patients (Group 1, age 50 ± 14 years, 95% females) without clinical evidence for cardiac involvement and 42 age- and gender-matched control subjects (Group 2, age 49 ± 13 years, 95% females) were evaluated with comprehensive 2D and Doppler echocardiography, including tissue Doppler imaging analysis. Positive peak left atrial longitudinal strain (ϵ pos peak), second positive left atrial longitudinal strain (sec ϵ pos peak), and negative left atrial longitudinal strain (ϵ neg peak) were measured using a 12-segment model for the LA, by commercially available semi-automated 2D speckle-tracking software (EchoPac PC version 108.1.4, GE Healthcare, Horten, Norway). Results All SSc patients had a normal left ventricular ejection fraction (63.1 ± 4%). SSc patients did not differ from controls in E/A (Group 1 = 1.1 ± 0.4 vs Group 2 = 1.3 ± 0.4, p = .14) or pulmonary arterial systolic pressure (Group 1 = 24.1 ± 8 mmHg vs Group 2 = 21 ± 7 mmHg, p = .17). SSc patients did not show significantly different indexed LA volumes (Group 1 = 24.9 ± 5.3 ml/m2 vs Group 2 = 24.7 ± 4.4 ml/m2, p = .8), whereas E/e’ ratio was significantly higher in SSc (Group 1 = 7.6 ± 2.4 vs Group 2 = 6.5 ± 1.7, p<0.05), although still within normal values. LA strain values were significantly different between the two groups (ϵ pos peak Group 1 = 31.3 ± 4.2% vs Group 2 = 35.0 ± 7.6%, p

  7. Assessment of Speckle-Tracking Echocardiography-Derived Global Deformation Parameters During Supine Exercise in Children.

    PubMed

    Liu, Michael Y; Tacy, Theresa; Chin, Clifford; Obayashi, Derek Y; Punn, Rajesh

    2016-03-01

    Exercise echocardiography is an underutilized tool in pediatrics with current applications including detecting segmental wall abnormalities, assessing the utility of global ventricular function, and measuring pulmonary hemodynamics. No prior study has applied speckle-tracking echocardiography (STE) during exercise echocardiography in children. The aim of this study was to determine the feasibility of measuring speckle-tracking-derived peak systolic velocities, global longitudinal and circumferential strain, and global strain rates at various phases of exercise. Ninety-seven healthy children underwent cardiopulmonary exercise testing using supine cycle ergometry. The exercise stress test consisted of baseline pulmonary function testing, monitoring of blood pressure and heart rate responses, electrocardiographic recordings, and oxygen saturations while subjects pedaled against a ramp protocol based on body weight. Echocardiographic measurements and specifically speckle-tracking analysis were performed during exercise at baseline, at a heart rate of 160 beats per minute and at 10 min after exercise. Peak systolic velocity, peak systolic strain, and peak systolic strain rate at these three phases were compared in the subjects in which all measurements were accurately obtained. We were able to complete peak velocity, strain, and strain rate measurements in all three exercise phases for 36 out of the 97 subjects tested. There was no significant difference between the feasibility of measuring circumferential versus longitudinal strain (p = 0.25, B-corrected = 0.75). In the 36 subjects studied, the magnitude of circumferential strain values decreased from -18.3 ± 4.8 to -13.7 ± 4.0 % from baseline to HR 160 (p < 0.0001, B-corrected < 0.0001), before returning to -19.6 ± 4.4 % at recovery (p = 0.19 when compared to baseline). Longitudinal strain did not vary significantly from baseline to HR 160 (from -17.7 ± 4.4 to -16.6 ± 4.4 %, p = 0.16); likewise the average

  8. Modeled and Measured Partially Coherent Illumination Speckle Effects from Sloped Surfaces for Tactical Tracking

    DTIC Science & Technology

    2015-03-26

    normalized by the mean pixel irradiance. Approximately 150 independent speckles are present. Keep in mind that a speckle can be bright, dark, or...relevant. With these goals in mind , a rapid simulation approach was developed which uses a weighted sum of fully speckled field amplitude and...Huamin Yang. “Temporal spectrum of beam wander for Gaussian Shell-model beams propagating in atmospheric turbulence with finite outer scale,” Opt

  9. Speckle tracking echocardiography in chronic obstructive pulmonary disease and overlapping obstructive sleep apnea

    PubMed Central

    Pizarro, Carmen; van Essen, Fabian; Linnhoff, Fabian; Schueler, Robert; Hammerstingl, Christoph; Nickenig, Georg; Skowasch, Dirk; Weber, Marcel

    2016-01-01

    Background COPD and congestive heart failure represent two disease entities of growing global burden that share common etiological features. Therefore, we aimed to identify the degree of left ventricular (LV) dysfunction in COPD as a function of COPD severity stages and concurrently placed particular emphasis on the presence of overlapping obstructive sleep apnea (OSA). Methods A total of 85 COPD outpatients (64.1±10.4 years, 54.1% males) and 20 controls, matched for age, sex, and smoking habits, underwent speckle tracking echocardiography for LV longitudinal strain imaging. Complementary 12-lead electrocardiography, laboratory testing, and overnight screening for sleep-disordered breathing using the SOMNOcheck micro® device were performed. Results Contrary to conventional echocardiographic parameters, speckle tracking echocardiography revealed significant impairment in global LV strain among COPD patients compared to control smokers (−13.3%±5.4% vs −17.1%±1.8%, P=0.04). On a regional level, the apical septal LV strain was reduced in COPD (P=0.003) and associated with the degree of COPD severity (P=0.02). With regard to electrocardiographic findings, COPD patients exhibited a significantly higher mean heart rate than controls (71.4±13.0 beats per minute vs 60.3±7.7 beats per minute, P=0.001) that additionally increased over Global Initiative for Chronic Obstructive Lung Disease stages (P=0.01). Albeit not statistically significant, COPD led to elevated N-terminal pro-brain natriuretic peptide levels (453.2±909.0 pg/mL vs 96.8±70.0 pg/mL, P=0.08). As to somnological testing, the portion of COPD patients exhibiting overlapping OSA accounted for 5.9% and did not significantly vary either in comparison to controls (P=0.07) or throughout the COPD Global Initiative for Chronic Obstructive Lung Disease stages (P=0.49). COPD-OSA overlap solely correlated with nocturnal hypoxemic events, whereas LV performance status was unrelated to coexisting OSA. Conclusion

  10. Early detection of cardiac dysfunction in the type 1 diabetic heart using speckle-tracking based strain imaging.

    PubMed

    Shepherd, Danielle L; Nichols, Cody E; Croston, Tara L; McLaughlin, Sarah L; Petrone, Ashley B; Lewis, Sara E; Thapa, Dharendra; Long, Dustin M; Dick, Gregory M; Hollander, John M

    2016-01-01

    Enhanced sensitivity in echocardiographic analyses may allow for early detection of changes in cardiac function beyond the detection limits of conventional echocardiographic analyses, particularly in a small animal model. The goal of this study was to compare conventional echocardiographic measurements and speckle-tracking based strain imaging analyses in a small animal model of type 1 diabetes mellitus. Conventional analyses revealed differences in ejection fraction, fractional shortening, cardiac output, and stroke volume in diabetic animals relative to controls at 6-weeks post-diabetic onset. In contrast, when assessing short- and long-axis speckle-tracking based strain analyses, diabetic mice showed changes in average systolic radial strain, radial strain rate, radial displacement, and radial velocity, as well as decreased circumferential and longitudinal strain rate, as early as 1-week post-diabetic onset and persisting throughout the diabetic study. Further, we performed regional analyses for the LV and found that the free wall region was affected in both the short- and long-axis when assessing radial dimension parameters. These changes began 1-week post-diabetic onset and remained throughout the progression of the disease. These findings demonstrate the use of speckle-tracking based strain as an approach to elucidate cardiac dysfunction from a global perspective, identifying left ventricular cardiac regions affected during the progression of type 1 diabetes mellitus earlier than contractile changes detected by conventional echocardiographic measurements.

  11. 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.

  12. Reversible Changes of Left Atrial Function during Pregnancy Assessed by Two-Dimensional Speckle Tracking Echocardiography

    PubMed Central

    Song, Guang; Liu, Jing; Ren, Weidong; Qiao, Wei; Zhang, Jing; Zhan, Ying; Bi, Wenjing

    2015-01-01

    Background Left ventricular diastolic function is impaired during pregnancy. However, changes in left atrial (LA) function remain unclear. We aimed to evaluate changes in LA function during pregnancy using two-dimensional speckle tracking echocardiography (2DSTE). Methods and Results 50 pregnant and 50 healthy nulliparous (control group) women were enrolled in this study. All pregnant women were followed up postpartum in sixth-month. The LA maximum volume, LA minimal volume and LA preatrial contraction volume were obtained using biplane modified Simpson’s method. LA filling volume, LA expansion index, LA ejection fraction, passive volume, passive emptying index, active volume, and active emptying index were calculated. LA longitudinal systolic strain (SS), systolic strain rate (s-SR), early diastolic strain rate (e-SR), and late diastolic strain rate (a-SR) were obtained by 2DSTE. Compared to the control group, the reservoir function was increased in pregnant patients (P<0.05); conduit function was decreased in pregnant patients (P<0.05); booster pump function was increased in pregnant patients (P<0.05). There was no statistically significant difference between the control group and postpartum group. Conclusions LA reservoir and booster pump function were increased, while conduit function was decreased during pregnancy using 2DSTE. The changes were reversible. 2DSTE can easily assess LA function during pregnancy with good repeatability. PMID:25933100

  13. Feasibility of radial and circumferential strain analysis using 2D speckle tracking echocardiography in cats

    PubMed Central

    TAKANO, Hiroshi; ISOGAI, Tomomi; AOKI, Takuma; WAKAO, Yoshito; FUJII, Yoko

    2014-01-01

    The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM were performed. Segmental assessments of left ventricle (LV) wall for strain and strain rate variables in cats with HCM were also performed. As a result, technically adequate images were obtained in 97.6% of the segments for STE analysis. Sedation using buprenorphine and acepromazine did not affect any global strain nor strain rate variable. In LV segments of cats with HCM, reduced segmental radial strain and strain rate variables had significantly related with segmental LV hypertrophy. It is concluded that STE analysis using short axis images of LV appeared to be clinically feasible in cats, having the possibility to be useful for detecting myocardial dysfunctions in cats with diseased heart. PMID:25373881

  14. Feasibility of radial and circumferential strain analysis using 2D speckle tracking echocardiography in cats.

    PubMed

    Takano, Hiroshi; Isogai, Tomomi; Aoki, Takuma; Wakao, Yoshito; Fujii, Yoko

    2015-02-01

    The purpose of the present study is to investigate the feasibility of strain analysis using speckle tracking echocardiography (STE) in cats and to evaluate STE variables in cats with hypertrophic cardiomyopathy (HCM). Sixteen clinically healthy cats and 17 cats with HCM were used. Radial and circumferential strain and strain rate variables in healthy cats were measured using STE to assess the feasibility. Comparisons of global strain and strain variables between healthy cats and cats with HCM were performed. Segmental assessments of left ventricle (LV) wall for strain and strain rate variables in cats with HCM were also performed. As a result, technically adequate images were obtained in 97.6% of the segments for STE analysis. Sedation using buprenorphine and acepromazine did not affect any global strain nor strain rate variable. In LV segments of cats with HCM, reduced segmental radial strain and strain rate variables had significantly related with segmental LV hypertrophy. It is concluded that STE analysis using short axis images of LV appeared to be clinically feasible in cats, having the possibility to be useful for detecting myocardial dysfunctions in cats with diseased heart.

  15. Integrating eye tracking and motion sensor on mobile phone for interactive 3D display

    NASA Astrophysics Data System (ADS)

    Sun, Yu-Wei; Chiang, Chen-Kuo; Lai, Shang-Hong

    2013-09-01

    In this paper, we propose an eye tracking and gaze estimation system for mobile phone. We integrate an eye detector, cornereye center and iso-center to improve pupil detection. The optical flow information is used for eye tracking. We develop a robust eye tracking system that integrates eye detection and optical-flow based image tracking. In addition, we further incorporate the orientation sensor information from the mobile phone to improve the eye tracking for accurate gaze estimation. We demonstrate the accuracy of the proposed eye tracking and gaze estimation system through experiments on some public video sequences as well as videos acquired directly from mobile phone.

  16. 3D polarisation speckle as a demonstration of tensor version of the van Cittert-Zernike theorem for stochastic electromagnetic beams

    NASA Astrophysics Data System (ADS)

    Ma, Ning; Zhao, Juan; Hanson, Steen G.; Takeda, Mitsuo; Wang, Wei

    2016-10-01

    Laser speckle has received extensive studies of its basic properties and associated applications. In the majority of research on speckle phenomena, the random optical field has been treated as a scalar optical field, and the main interest has been concentrated on their statistical properties and applications of its intensity distribution. Recently, statistical properties of random electric vector fields referred to as Polarization Speckle have come to attract new interest because of their importance in a variety of areas with practical applications such as biomedical optics and optical metrology. Statistical phenomena of random electric vector fields have close relevance to the theories of speckles, polarization and coherence theory. In this paper, we investigate the correlation tensor for stochastic electromagnetic fields modulated by a depolarizer consisting of a rough-surfaced retardation plate. Under the assumption that the microstructure of the scattering surface on the depolarizer is as fine as to be unresolvable in our observation region, we have derived a relationship between the polarization matrix/coherency matrix for the modulated electric fields behind the rough-surfaced retardation plate and the coherence matrix under the free space geometry. This relation is regarded as entirely analogous to the van Cittert-Zernike theorem of classical coherence theory. Within the paraxial approximation as represented by the ABCD-matrix formalism, the three-dimensional structure of the generated polarization speckle is investigated based on the correlation tensor, indicating a typical carrot structure with a much longer axial dimension than the extent in its transverse dimension.

  17. Speckle tracking in a phantom and feature-based tracking in liver in the presence of respiratory motion using 4D ultrasound.

    PubMed

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

    2010-06-21

    We have evaluated a 4D ultrasound-based motion tracking system developed for tracking of abdominal organs during therapy. Tracking accuracy and precision were determined using a tissue-mimicking phantom, by comparing tracked motion with known 3D sinusoidal motion. The feasibility of tracking 3D liver motion in vivo was evaluated by acquiring 4D ultrasound data from four healthy volunteers. For two of these volunteers, data were also acquired whilst simultaneously measuring breath flow using a spirometer. Hepatic blood vessels, tracked off-line using manual tracking, were used as a reference to assess, in vivo, two types of automated tracking algorithm: incremental (from one volume to the next) and non-incremental (from the first volume to each subsequent volume). For phantom-based experiments, accuracy and precision (RMS error and SD) were found to be 0.78 mm and 0.54 mm, respectively. For in vivo measurements, mean absolute distance and standard deviation of the difference between automatically and manually tracked displacements were less than 1.7 mm and 1 mm respectively in all directions (left-right, anterior-posterior and superior-inferior). In vivo non-incremental tracking gave the best agreement. In both phantom and in vivo experiments, tracking performance was poorest for the elevational component of 3D motion. Good agreement between automatically and manually tracked displacements indicates that 4D ultrasound-based motion tracking has potential for image guidance applications in therapy.

  18. Speckle tracking in a phantom and feature-based tracking in liver in the presence of respiratory motion using 4D ultrasound

    NASA Astrophysics Data System (ADS)

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

    2010-06-01

    We have evaluated a 4D ultrasound-based motion tracking system developed for tracking of abdominal organs during therapy. Tracking accuracy and precision were determined using a tissue-mimicking phantom, by comparing tracked motion with known 3D sinusoidal motion. The feasibility of tracking 3D liver motion in vivo was evaluated by acquiring 4D ultrasound data from four healthy volunteers. For two of these volunteers, data were also acquired whilst simultaneously measuring breath flow using a spirometer. Hepatic blood vessels, tracked off-line using manual tracking, were used as a reference to assess, in vivo, two types of automated tracking algorithm: incremental (from one volume to the next) and non-incremental (from the first volume to each subsequent volume). For phantom-based experiments, accuracy and precision (RMS error and SD) were found to be 0.78 mm and 0.54 mm, respectively. For in vivo measurements, mean absolute distance and standard deviation of the difference between automatically and manually tracked displacements were less than 1.7 mm and 1 mm respectively in all directions (left-right, anterior-posterior and superior-inferior). In vivo non-incremental tracking gave the best agreement. In both phantom and in vivo experiments, tracking performance was poorest for the elevational component of 3D motion. Good agreement between automatically and manually tracked displacements indicates that 4D ultrasound-based motion tracking has potential for image guidance applications in therapy.

  19. 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.

  20. 3D Ultrasonic Needle Tracking with a 1.5D Transducer Array for Guidance of Fetal Interventions

    PubMed Central

    West, Simeon J.; Mari, Jean-Martial; Ourselin, Sebastien; David, Anna L.; Desjardins, Adrien E.

    2016-01-01

    Ultrasound image guidance is widely used in minimally invasive procedures, including fetal surgery. In this context, maintaining visibility of medical devices is a significant challenge. Needles and catheters can readily deviate from the ultrasound imaging plane as they are inserted. When the medical device tips are not visible, they can damage critical structures, with potentially profound consequences including loss of pregnancy. In this study, we performed 3D ultrasonic tracking of a needle using a novel probe with a 1.5D array of transducer elements that was driven by a commercial ultrasound system. A fiber-optic hydrophone integrated into the needle received transmissions from the probe, and data from this sensor was processed to estimate the position of the hydrophone tip in the coordinate space of the probe. Golay coding was used to increase the signal-to-noise (SNR). The relative tracking accuracy was better than 0.4 mm in all dimensions, as evaluated using a water phantom. To obtain a preliminary indication of the clinical potential of 3D ultrasonic needle tracking, an intravascular needle insertion was performed in an in vivo pregnant sheep model. The SNR values ranged from 12 to 16 at depths of 20 to 31 mm and at an insertion angle of 49° relative to the probe surface normal. The results of this study demonstrate that 3D ultrasonic needle tracking with a fiber-optic hydrophone sensor and a 1.5D array is feasible in clinically realistic environments. PMID:28111644

  1. 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.

  2. The 3D Tele Motion Tracking for the Orthodontic Facial Analysis

    PubMed Central

    Nota, Alessandro; Marchetti, Enrico; Padricelli, Giuseppe; Marzo, Giuseppe

    2016-01-01

    Aim. This study aimed to evaluate the reliability of 3D-TMT, previously used only for dynamic testing, in a static cephalometric evaluation. Material and Method. A group of 40 patients (20 males and 20 females; mean age 14.2 ± 1.2 years; 12–18 years old) was included in the study. The measurements obtained by the 3D-TMT cephalometric analysis with a conventional frontal cephalometric analysis were compared for each subject. Nine passive markers reflectors were positioned on the face skin for the detection of the profile of the patient. Through the acquisition of these points, corresponding plans for three-dimensional posterior-anterior cephalometric analysis were found. Results. The cephalometric results carried out with 3D-TMT and with traditional posterior-anterior cephalometric analysis showed the 3D-TMT system values are slightly higher than the values measured on radiographs but statistically significant; nevertheless their correlation is very high. Conclusion. The recorded values obtained using the 3D-TMT analysis were correlated to cephalometric analysis, with small but statistically significant differences. The Dahlberg errors resulted to be always lower than the mean difference between the 2D and 3D measurements. A clinician should use, during the clinical monitoring of a patient, always the same method, to avoid comparing different millimeter magnitudes. PMID:28044130

  3. Accurate and high-performance 3D position measurement of fiducial marks by stereoscopic system for railway track inspection

    NASA Astrophysics Data System (ADS)

    Gorbachev, Alexey A.; Serikova, Mariya G.; Pantyushina, Ekaterina N.; Volkova, Daria A.

    2016-04-01

    Modern demands for railway track measurements require high accuracy (about 2-5 mm) of rails placement along the track to ensure smooth, safe and fast transportation. As a mean for railways geometry measurements we suggest a stereoscopic system which measures 3D position of fiducial marks arranged along the track by image processing algorithms. The system accuracy was verified during laboratory tests by comparison with precise laser tracker indications. The accuracy of +/-1.5 mm within a measurement volume 150×400×5000 mm was achieved during the tests. This confirmed that the stereoscopic system demonstrates good measurement accuracy and can be potentially used as fully automated mean for railway track inspection.

  4. Echocardiographic analysis of the left ventricular function in young athletes: a focus on speckle tracking imaging

    PubMed Central

    Charfeddine, Salma; Mallek, Souad; Triki, Faten; Hammami, Rania; Abid, Dorra; Abid, Leila; Kammoun, Samir

    2016-01-01

    Introduction The objectives were to assess the left ventricular (LV) structure and function in regularly trained young athletes, using 2 D conventional echocardiographic (echo) methods and speckle tracking echocardiography (STE). An observational cross-sectional study. Methods Thirty-three footballers and 20 healthy untrained subjects were included in the study. The systolic and diastolic LV functions were evaluated by 2D conventional echo parameters, Doppler method and STE. Results All the found values were within the normal range. The LV End Diastolic Diameter (LVED 37.24±2.08 mm/m2) and the LV Mass index (LVMi 97.93±15.58 g/m2) were significantly higher in young athletes as compared with controls. There was no difference regarding the LV systolic function assessed by conventional echo parameters in the 2 study groups. Regarding the diastolic function, the transmitral inflow velocities ratio was significantly higher in athletes (E/A = 2.10±0.49 versus 1.64±0.26, p< 0.001) but there was no difference in the filling pressure in the 2 groups. The STE demonstrated a different pattern of LV deformation in the different groups. A significant lower LV global longitudinal strain (GLS -20.68±2.05 versus -22.99±2.32 %, p<0.001) and higher radial and circumferential strains have been found in the young athletes as compared with controls. A significant relationship between the GLS values and LVED (r= 0.299, p = 0.03) and LVMi was also reported in athletes. Conclusion While conventional morphological and functional echocardiographic parameters failed to distinguish the adaptations in the athlete’s heart, deformation parameters showed a different pattern of LV mechanics in young footballers versus controls. PMID:28292133

  5. Outcome prediction in sepsis: Speckle tracking echocardiography based assessment of myocardial function

    PubMed Central

    2014-01-01

    Introduction Speckle tracking echocardiography (STE) is a relatively novel and sensitive method for assessing ventricular function and may unmask myocardial dysfunction not appreciated with conventional echocardiography. The association of ventricular dysfunction and prognosis in sepsis is unclear. We sought to evaluate frequency and prognostic value of biventricular function, assessed by STE in patients with severe sepsis or septic shock. Methods Over an eighteen-month period, sixty patients were prospectively imaged by transthoracic echocardiography within 24 hours of meeting severe sepsis criteria. Myocardial function assessment included conventional measures and STE. Association with mortality was assessed over 12 months. Results Mortality was 33% at 30 days (n = 20) and 48% at 6 months (n = 29). 32% of patients had right ventricle (RV) dysfunction based on conventional assessment compared to 72% assessed with STE. 33% of patients had left ventricle (LV) dysfunction based on ejection fraction compared to 69% assessed with STE. RV free wall longitudinal strain was moderately associated with six-month mortality (OR 1.1, 95% confidence interval, CI, 1.02-1.26, p = 0.02, area under the curve, AUC, 0.68). No other conventional echocardiography or STE method was associated with survival. After adjustment (for example, for mechanical ventilation) severe RV free wall longitudinal strain impairment remained associated with six-month mortality. Conclusion STE may unmask systolic dysfunction not seen with conventional echocardiography. RV dysfunction unmasked by STE, especially when severe, was associated with high mortality in patients with severe sepsis or septic shock. LV dysfunction was not associated with survival outcomes. PMID:25015102

  6. Application of 3D digital image correlation to track displacements and strains of canvas paintings exposed to relative humidity changes.

    PubMed

    Malowany, Krzysztof; Tymińska-Widmer, Ludmiła; Malesa, Marcin; Kujawińska, Małgorzata; Targowski, Piotr; Rouba, Bogumiła J

    2014-03-20

    This paper introduces a methodology for tracking displacements in canvas paintings exposed to relative humidity changes. Displacements are measured by means of the 3D digital image correlation method that is followed by a postprocessing of displacement data, which allows the separation of local displacements from global displacement maps. The applicability of this methodology is tested on measurements of a model painting on canvas with introduced defects causing local inhomogeneity. The method allows the evaluation of conservation methods used for repairing canvas supports.

  7. 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.

  8. The influence of acute unloading on left ventricular strain and strain rate by speckle tracking echocardiography in a porcine model.

    PubMed

    Dahle, Geir Olav; Stangeland, Lodve; Moen, Christian Arvei; Salminen, Pirjo-Riitta; Haaverstad, Rune; Matre, Knut; Grong, Ketil

    2016-05-15

    Noninvasive measurements of myocardial strain and strain rate by speckle tracking echocardiography correlate to cardiac contractile state but also to load, which may weaken their value as indices of inotropy. In a porcine model, we investigated the influence of acute dynamic preload reductions on left ventricular strain and strain rate and their relation to the pressure-conductance catheter-derived preload recruitable stroke work (PRSW) and peak positive first derivative of left ventricular pressure (LV-dP/dtmax). Speckle tracking strain and strain rate in the longitudinal, circumferential, and radial directions were measured during acute dynamic reductions of end-diastolic volume during three different myocardial inotropic states. Both strain and strain rate were sensitive to unloading of the left ventricle (P < 0.001), but the load dependency for strain rate was modest compared with strain. Changes in longitudinal and circumferential strain correlated more strongly to changes in end-diastolic volume (r = -0.86 and r = -0.72) than did radial strain (r = 0.35). Longitudinal, circumferential, and radial strain significantly correlated with LV-dP/dtmax (r = -0.53, r = -0.46, and r = 0.86), whereas only radial strain correlated with PRSW (r = 0.55). Strain rate in the longitudinal, circumferential and radial direction significantly correlated with both PRSW (r = -0.64, r = -0.58, and r = 0.74) and LV-dP/dtmax (r = -0.95, r = -0.70, and r = 0.85). In conclusion, the speckle tracking echocardiography-derived strain rate is more robust to dynamic ventricular unloading than strain. Longitudinal and circumferential strain could not predict load-independent contractility. Strain rates, and especially in the radial direction, are good predictors of preload-independent inotropic markers derived from conductance catheter.

  9. 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

  10. Maximum likelihood estimate of target angles for a conical scan tracking system in the presence of speckle.

    PubMed

    Lubnau, D G

    1977-01-01

    The equation for the maximum likelihood estimate of target angle is derived for a conical scan tracking system when the target produces speckle and Gaussian noise is present. Operation with a direct detection receiver is assumed with the average photon flux large enough so that the discrete nature of photoelectric events may be ignored. For large average SNRs, the estimate is shown to be unbiased and the variance of the estimate limited by both the average SNR and the number of degrees of freedom of the detected field.

  11. X-ray microscopy using two phase contrast imaging techniques: two dimensional grating interferometry and speckle tracking

    NASA Astrophysics Data System (ADS)

    Wang, Hongchang; Berujon, Sebastien; Pape, Ian; Sawhney, Kawal

    2013-10-01

    Two phase contrast imaging techniques, namely two dimensional grating interferometry and X-ray speckle tracking (XST), have been combined with the use of a Fresnel Zone Plate (FZP) for application to X-ray microscopy. Both techniques allows the phase shift introduced by a sample on a hard X-ray beam in two dimensions, to be recovered with a high sensitivity and low requirements on transverse and longitudinal coherence. Sub-micron phase imaging of carbon fibres was achieved using the two methods thanks to the high magnification ratio of the FZP. Advantages, drawbacks and differences between these two techniques for X-ray microscopy are discussed.

  12. Computer Vision Tracking Using Particle Filters for 3D Position Estimation

    DTIC Science & Technology

    2014-03-27

    5 2.2 Photogrammetry ...focus on particle filters. 2.2 Photogrammetry Photogrammetry is the process of determining 3-D coordinates through images. The mathematical underpinnings...of photogrammetry are rooted in the 1480s with Leonardo da Vinci’s study of perspectives [8, p. 1]. However, digital photogrammetry did not emerge

  13. 3D Visual Tracking of an Articulated Robot in Precision Automated Tasks

    PubMed Central

    Alzarok, Hamza; Fletcher, Simon; Longstaff, Andrew P.

    2017-01-01

    The most compelling requirements for visual tracking systems are a high detection accuracy and an adequate processing speed. However, the combination between the two requirements in real world applications is very challenging due to the fact that more accurate tracking tasks often require longer processing times, while quicker responses for the tracking system are more prone to errors, therefore a trade-off between accuracy and speed, and vice versa is required. This paper aims to achieve the two requirements together by implementing an accurate and time efficient tracking system. In this paper, an eye-to-hand visual system that has the ability to automatically track a moving target is introduced. An enhanced Circular Hough Transform (CHT) is employed for estimating the trajectory of a spherical target in three dimensions, the colour feature of the target was carefully selected by using a new colour selection process, the process relies on the use of a colour segmentation method (Delta E) with the CHT algorithm for finding the proper colour of the tracked target, the target was attached to the six degree of freedom (DOF) robot end-effector that performs a pick-and-place task. A cooperation of two Eye-to Hand cameras with their image Averaging filters are used for obtaining clear and steady images. This paper also examines a new technique for generating and controlling the observation search window in order to increase the computational speed of the tracking system, the techniques is named Controllable Region of interest based on Circular Hough Transform (CRCHT). Moreover, a new mathematical formula is introduced for updating the depth information of the vision system during the object tracking process. For more reliable and accurate tracking, a simplex optimization technique was employed for the calculation of the parameters for camera to robotic transformation matrix. The results obtained show the applicability of the proposed approach to track the moving robot

  14. 3D Visual Tracking of an Articulated Robot in Precision Automated Tasks.

    PubMed

    Alzarok, Hamza; Fletcher, Simon; Longstaff, Andrew P

    2017-01-07

    The most compelling requirements for visual tracking systems are a high detection accuracy and an adequate processing speed. However, the combination between the two requirements in real world applications is very challenging due to the fact that more accurate tracking tasks often require longer processing times, while quicker responses for the tracking system are more prone to errors, therefore a trade-off between accuracy and speed, and vice versa is required. This paper aims to achieve the two requirements together by implementing an accurate and time efficient tracking system. In this paper, an eye-to-hand visual system that has the ability to automatically track a moving target is introduced. An enhanced Circular Hough Transform (CHT) is employed for estimating the trajectory of a spherical target in three dimensions, the colour feature of the target was carefully selected by using a new colour selection process, the process relies on the use of a colour segmentation method (Delta E) with the CHT algorithm for finding the proper colour of the tracked target, the target was attached to the six degree of freedom (DOF) robot end-effector that performs a pick-and-place task. A cooperation of two Eye-to Hand cameras with their image Averaging filters are used for obtaining clear and steady images. This paper also examines a new technique for generating and controlling the observation search window in order to increase the computational speed of the tracking system, the techniques is named Controllable Region of interest based on Circular Hough Transform (CRCHT). Moreover, a new mathematical formula is introduced for updating the depth information of the vision system during the object tracking process. For more reliable and accurate tracking, a simplex optimization technique was employed for the calculation of the parameters for camera to robotic transformation matrix. The results obtained show the applicability of the proposed approach to track the moving robot

  15. Endurance and Strength Athlete's Heart: Analysis of Myocardial Deformation by Speckle Tracking Echocardiography

    PubMed Central

    Santoro, Amato; Antonelli, Giovanni; Caputo, Maria; Padeletti, Margherita; Lisi, Matteo; Mondillo, Sergio

    2014-01-01

    Background Intensive training induces two morphological myocardial typologies of athlete's heart. Endurance training (ET) induces eccentric remodeling, bradycardia and better diastolic filling. Strength training (ST) determines concentric chamber remodelling maintaining a normal heart rate (HR). Aim of the study was to compare ET and ST athletes' heart using speckle tracking echocardiography (STE). Methods 33 professional ET, 36 ST athletes, and 17 healthy controls (CT) were enrolled. All subjects underwent standard transthoracic echocardiography at rest and STE. Results In ET group, HR was lower than ST group and CT group (p < 0.001; p < 0.01). ET group had higher E/A ratio than ST group and CT group (p < 0.01; p < 0.001). The left ventricular apical circumferential strain in ET group was lower than ST group and CT group (-21.6 ± 4.1% vs. -26.8 ± 7.7%, p < 0.05; vs. -27.8 ± 5.6%, p < 0.01). ET group had lower left ventricular twist (LVT) and untwisting (UTW) than ST group (6.2 ± 0.1° vs. 12.0 ± 0.1°, p < 0.01; -67.3 ± 22.9°/s vs. -122.5 ± 52.8°/s, p < 0.01) and CT group (10.0 ± 0.1°, p < 0.01; -103.3 ± 29.3°/s, p < 0.01). The univariate analysis showed significant correlation between E/A ratio and HR (r = -0.54; p < 0.001), LVT (r = -0.45; p < 0.01), UTW (r = 0.24; p < 0.05). At the multivariate analysis only HR was confirmed as independent predictor of diastolic function in all groups (Beta -0.52; p < 0.001). Conclusion In ET there was a better global systolic and diastolic functional reserve at rest observed with strain analysis and it maybe depended on autonomic modulation. PMID:25580194

  16. Echocardiographic assessment of right ventricle adaptation to endurance training in young rowers – speckle tracking echocardiography

    PubMed Central

    Krol, W; Burkhard-Jagodzinska, K; Jakubiak, A; Klusiewicz, A; Chwalbinska, J; Pokrywka, A; Sitkowski, D; Dluzniewski, M; Braksator, W

    2016-01-01

    The aim of this study was to determine the relationship between the degree of cardiorespiratory fitness and the function of the right ventricle (RV). 117 rowers, age 17.5±1.5 years. All subjects underwent cardiopulmonary exercise. Standard echocardiography and 2D speckle tracking echocardiography with evaluation of longitudinal strain in each segment of the RV (basal – RVLS-B; mid – RVLS-M, apical – RVLS-A) and global RV free-wall strain (RVLS-G) were performed. RVLS-B values were lower compared to the RVLS-M (-25.8±4.4 vs -29.3±3.5; p<0.001) and RVLS-A values (-25.8±4.4 vs -26.2±3.4; p=0.85). Correlations between VO2max and RVLS were observed in men: RVLS-G strain (r = 0.43; p <0.001); RVLS-B (r = 0.30; p = 0.02); RVLS-M (r = 0.38; p = 0.02). A similar relationship was not observed in the group of women. The strongest predictors corresponding to a change in global and basal strain were VO2max and training time: RVLS-G (VO2max: β = 0.18, p = 0.003; training time: β = -0.39; p = 0.02) and RVLS-B (VO2max: β = 0.23; p = 0.0001 training time: β = -1.16; p = 0.0001). The global and regional reduction of RV systolic function positively correlates with the level of fitness, and this relationship is observed already in young athletes. The character of the relationship between RV deformation parameters and the variables that determine the physical performance depend on gender. The dependencies apply to the proximal fragment of the RV inflow tract, which may be a response to the type of flow during exercise in endurance athletes. PMID:28090137

  17. Subclinical Ventricular Dysfunction Detected by Speckle Tracking Two Years after Use of Anthracycline

    PubMed Central

    de Almeida, André Luiz Cerqueira; Silva, Viviane Almeida; de Souza Filho, Alberto Teófilo; Rios, Vinicius Guedes; Lopes, João Ricardo Pinto; de Afonseca, Samuel Oliveira; Cunha, Daniel de Castro Araújo; Mendes, Murilo Oliveira da Cunha; Miranda, Danilo Leal; dos Santos Júnior, Edval Gomes

    2015-01-01

    Background Heart failure is a severe complication associated with doxorubicin (DOX) use. Strain, assessed by two-dimensional speckle tracking (2D-STE), has been shown to be useful in identifying subclinical ventricular dysfunction. Objectives a) To investigate the role of strain in the identification of subclinical ventricular dysfunction in patients who used DOX; b) to investigate determinants of strain response in these patients. Methods Cross-sectional study with 81 participants: 40 patients who used DOX ±2 years before the study and 41 controls. All participants had left ventricular ejection fraction (LVEF) ≥55%. Total dose of DOX was 396mg (242mg/ms2). The systolic function of the LV was evaluated by LVEF (Simpson), as well as by longitudinal (εLL), circumferential (εCC), and radial (εRR) strains. Multivariate linear regression (MLR) analysis was performed using εLL (model 1) and εCC (model 2) as dependent variables. Results Systolic and diastolic blood pressure values were higher in the control group (p < 0.05). εLL was lower in the DOX group (-12.4 ±2.6%) versus controls (-13.4 ± 1.7%; p = 0.044). The same occurred with εCC: -12.1 ± 2.7% (DOX) versus -16.7 ± 3.6% (controls; p < 0.001). The S’ wave was shorter in the DOX group (p = 0.035). On MLR, DOX was an independent predictor of reduced εCC (B = -4.429, p < 0.001). DOX (B = -1.289, p = 0.012) and age (B = -0.057, p = 0.029) were independent markers of reduced εLL. Conclusion a) εLL, εCC and the S’ wave are reduced in patients who used DOX ±2 years prior to the study despite normal LVEF, suggesting the presence of subclinical ventricular dysfunction; b) DOX was an independent predictor of reduced εCC; c) prior use of DOX and age were independent markers of reduced εLL. PMID:25993590

  18. Evaluation of cardiac functions in juvenile systemic lupus erythematosus with two-dimensional speckle tracking echocardiography.

    PubMed

    Dedeoglu, Reyhan; Şahin, Sezgin; Koka, Aida; Öztunç, Funda; Adroviç, Amra; Barut, Kenan; Cengiz, Dicle; Kasapçopur, Özgür

    2016-08-01

    The aim of this study was to investigate subclinical systolic and diastolic dysfunction in juvenile-onset systemic lupus erythematosus (j-SLE) patients with speckle tracking echocardiography (STE) and the effects of disease activity on left ventricular (LV) regional functions. Thirty-five patients with j-SLE and 30 healthy children (control group) were evaluated between January and August 2015. STE was performed on all patients and controls. Medical records, including diagnosis criteria, age at diagnosis, and duration of disease, were evaluated. SLE disease activity was assessed using the SLE Disease Activity Index (SLEDAI). j-SLE patients had lower ejection fraction than did control subjects but still within normal range. LV end-diastolic and end-systolic dimensions were significantly larger in j-SLE patients (32.43 ± 3.2 vs 28.3 ± 3.1 and 21.1 ± 1.9 vs 18.9.0 ± 2.2, respectively; p = 0.001). There was a significant reduction in longitudinal strain of LV segments in the j-SLE patients compared with controls. J-SLE patients were further divided into subgroups. Group 1 comprised patients having SLEDAI scores >8 at the onset of disease but who improved with therapy during follow-up. Group 2 included j-SLE patients with SLEDAI scores >8 at diagnosis and persistently >4 at the end of follow-up. In the LV mid-inferior and mid-inferolateral segments, STE strain measurements of group 2 were significantly lower than those of group 1 (15.9 ± 6.4 vs 20.0 ± 4.4, 17.9 ± 7.2 vs 23.2 ± 3.8; p = 0.075, p = 0.055, respectively). Simple and non-invasive STE would be helpful in predicting cardiovascular prognosis with new therapeutic medications/interventions or in objectively comparing the effects of immunosuppressive drugs in comparison with preceding STE evaluation.

  19. 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.

  20. Determination of multidirectional myocardial deformations in cats with hypertrophic cardiomyopathy by using two-dimensional speckle-tracking echocardiography.

    PubMed

    Suzuki, Ryohei; Mochizuki, Yohei; Yoshimatsu, Hiroki; Teshima, Takahiro; Matsumoto, Hirotaka; Koyama, Hidekazu

    2017-02-01

    Objectives Hypertrophic cardiomyopathy, a primary disorder of the myocardium, is the most common cardiac disease in cats. However, determination of myocardial deformation with two-dimensional speckle-tracking echocardiography in cats with various stages of hypertrophic cardiomyopathy has not yet been reported. This study was designed to measure quantitatively multidirectional myocardial deformations of cats with hypertrophic cardiomyopathy. Methods Thirty-two client-owned cats with hypertrophic cardiomyopathy and 14 healthy cats serving as controls were enrolled and underwent assessment of myocardial deformation (peak systolic strain and strain rate) in the longitudinal, radial and circumferential directions. Results Longitudinal and radial deformations were reduced in cats with hypertrophic cardiomyopathy, despite normal systolic function determined by conventional echocardiography. Cats with severely symptomatic hypertrophic cardiomyopathy also had lower peak systolic circumferential strain, in addition to longitudinal and radial strain. Conclusions and relevance Longitudinal and radial deformation may be helpful in the diagnosis of hypertrophic cardiomyopathy. Additionally, the lower circumferential deformation in cats with severe hypertrophic cardiomyopathy may contribute to clinical findings of decompensation, and seems to be related to severe cardiac clinical signs. Indices of multidirectional myocardial deformations by two-dimensional speckle-tracking echocardiography may be useful markers and help to distinguish between cats with hypertrophic cardiomyopathy and healthy cats. Additionally, they may provide more detailed assessment of contractile function in cats with hypertrophic cardiomyopathy.

  1. Different patterns of left ventricular rotational mechanics in cardiac amyloidosis—results from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study

    PubMed Central

    Földeák, Dóra; Domsik, Péter; Kalapos, Anita; Sepp, Róbert; Borbényi, Zita; Forster, Tamás

    2015-01-01

    Cardiac amyloidosis (CA) is an infiltrative disease primarily caused by extracellular tissue deposition of amyloid fibrils in the myocardial interstitium. The aim of the present study was to examine left ventricular (LV) rotational mechanics in biopsy-proven CA by three-dimensional (3D) speckle-tracking echocardiography (STE). Ten patients (65.3±11.5 years, 6 males) with CA entered the study. The mean basal LV rotations were 0.3±3.8°, while mean apical LV rotations proved to be 7.0±3.3°. LV basal and apical rotations were in the same counterclockwise direction in 6 out of 10 CA patients demonstrating near absence of LV twist [LV rigid body rotation (RBR)]. Apico-basal difference was near 3 or less degrees in three patients with LV-RBR, and 6−10 degrees in the other three subjects with LV-RBR. One another patient showed normal rotational mechanics, while two patients had significant hyporotations and one had significant hyperrotations in normal directions. To conclude with, different patterns of LV rotational mechanics could be demonstrated in CA. LV RBR, the near absence of LV twist seems to be a frequent phenomenon in CA. PMID:26807368

  2. 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.

  3. 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

  4. 3D cloud detection and tracking system for solar forecast using multiple sky imagers

    DOE PAGES

    Peng, Zhenzhou; Yu, Dantong; Huang, Dong; ...

    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

  5. 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.

  6. Tracking immune-related cell responses to drug delivery microparticles in 3D dense collagen matrix.

    PubMed

    Obarzanek-Fojt, Magdalena; Curdy, Catherine; Loggia, Nicoletta; Di Lena, Fabio; Grieder, Kathrin; Bitar, Malak; Wick, Peter

    2016-10-01

    Beyond the therapeutic purpose, the impact of drug delivery microparticles on the local tissue and inflammatory responses remains to be further elucidated specifically for reactions mediated by the host immune cells. Such immediate and prolonged reactions may adversely influence the release efficacy and intended therapeutic pathway. The lack of suitable in vitro platforms limits our ability to gain insight into the nature of immune responses at a single cell level. In order to establish an in vitro 3D system mimicking the connective host tissue counterpart, we utilized reproducible, compressed, rat-tail collagen polymerized matrices. THP1 cells (human acute monocytic leukaemia cells) differentiated into macrophage-like cells were chosen as cell model and their functionality was retained in the dense rat-tail collagen matrix. Placebo microparticles were later combined in the immune cell seeded system during collagen polymerization and secreted pro-inflammatory factors: TNFα and IL-8 were used as immune response readout (ELISA). Our data showed an elevated TNFα and IL-8 secretion by macrophage THP1 cells indicating that Placebo microparticles trigger certain immune cell responses under 3D in vivo like conditions. Furthermore, we have shown that the system is sensitive to measure the differences in THP1 macrophage pro-inflammatory responses to Active Pharmaceutical Ingredient (API) microparticles with different API release kinetics. We have successfully developed a tissue-like, advanced, in vitro system enabling selective "readouts" of specific responses of immune-related cells. Such system may provide the basis of an advanced toolbox enabling systemic evaluation and prediction of in vivo microparticle reactions on human immune-related cells.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. Noninvasive model including right ventricular speckle tracking for the evaluation of pulmonary hypertension

    PubMed Central

    Mahran, Yossra; Schueler, Robert; Weber, Marcel; Pizarro, Carmen; Nickenig, Georg; Skowasch, Dirk; Hammerstingl, Christoph

    2016-01-01

    AIM To find parameters from transthorathic echocardiography (TTE) including speckle-tracking (ST) analysis of the right ventricle (RV) to identify precapillary pulmonary hypertension (PH). METHODS Forty-four patients with suspected PH undergoing right heart catheterization (RHC) were consecutively included (mean age 63.1 ± 14 years, 61% male gender). All patients underwent standardized TTE including ST analysis of the RV. Based on the subsequent TTE-derived measurements, the presence of PH was assessed: Left ventricular ejection fraction (LVEF) was calculated by Simpsons rule from 4Ch. Systolic pulmonary artery pressure (sPAP) was assessed with continuous wave Doppler of systolic tricuspid regurgitant velocity and regarded raised with values ≥ 30 mmHg as a surrogate parameter for RA pressure. A concomitantly elevated PCWP was considered a means to discriminate between the precapillary and postcapillary form of PH. PCWP was considered elevated when the E/e’ ratio was > 12 as a surrogate for LV diastolic pressure. E/e’ ratio was measured by gauging systolic and diastolic velocities of the lateral and septal mitral valve annulus using TDI mode. The results were then averaged with conventional measurement of mitral valve inflow. Furthermore, functional testing with six minutes walking distance (6MWD), ECG-RV stress signs, NT pro-BNP and other laboratory values were assessed. RESULTS PH was confirmed in 34 patients (precapillary PH, n = 15, postcapillary PH, n = 19). TTE showed significant differences in E/e’ ratio (precapillary PH: 12.3 ± 4.4, postcapillary PH: 17.3 ± 10.3, no PH: 12.1 ± 4.5, P = 0.02), LV volumes (ESV: 25.0 ± 15.0 mL, 49.9 ± 29.5 mL, 32.2 ± 13.6 mL, P = 0.027; EDV: 73.6 ± 24.0 mL, 110.6 ± 31.8 mL, 87.8 ± 33.0 mL, P = 0.021) and systolic pulmonary arterial pressure (sPAP: 61.2 ± 22.3 mmHg, 53.6 ± 20.1 mmHg, 31.2 ± 24.6 mmHg, P = 0.001). STRV analysis showed significant differences for apical RV longitudinal strain (RVAS: -7.5% ± 5

  13. Descending aortic mechanics and atrial fibrillation: a two-dimensional speckle tracking transesophageal echocardiography study.

    PubMed

    Teixeira, Rogério; Monteiro, Ricardo; Dinis, Paulo; Santos, Maria José; Botelho, Ana; Quintal, Nuno; Cardim, Nuno; Gonçalves, Lino

    2017-04-01

    Vascular mechanics assessed with two-dimensional speckle tracking echocardiography (2D-STE) could be used as a new imaging surrogate of vascular stiffening. The CHA2DS2-VASc score is considered accurate as an estimate of stroke risk in non-valvular AF, although many potential stroke risk factors have not been included in this scoring method. The purpose of this research is to study the feasibility of evaluating vascular mechanics at the descending aorta in non-valvular AF patients using transesophageal 2D-STE and to analyze the association between descending aortic mechanics and stroke. We prospectively recruited a group of 44 patients referred for a transesophageal echocardiogram (TEE) in the context of cardioversion for non-valvular AF. A short-axis view of the descending aorta, one to two centimeters after the aortic arch was selected for the vascular mechanics assessment with the 2D-STE methodology. The vascular mechanics parameters analyzed were circumferential aortic strain (CAS) and early circumferential aortic strain rate (CASR). A clinical assessment was performed with focus on the past stroke history and the CHA2DS2-VASc score. The mean age of our cohort was 65 ± 13 years and 75% were men; AF was known for 2.8 ± 2.5 years and it was considered paroxystic in 41% of cases. Waveforms adequate for measuring 2D-STE were present in 85% of the 264 descending aortic wall segments. The mean CAS was 3.5 ± 1.2% and the mean CASR was 0.7 ± 0.3 s(-1). The inter- and intra-observer variability for aortic mechanics was considered adequate. The median CHA2DS2VASc score was 2 (2-3). As the score increased we noted that both the CAS (r = -0.38, P = 0.01) and the CASR (r = -0.42, P < 0.01) decreased. Over 16% of the AF patients had a past history of stroke. These patients had lower values of both descending aortic strain [2.2 (1.8-2.6) vs. 3.9 (3.3-4.9)%, P < 0.01] and strain rate [0.4 (0.3-0.4) vs. 0.7 (0.6-1.1) s(-1), P < 0

  14. Sources of variation in assessing left atrial functions by 2D speckle-tracking echocardiography.

    PubMed

    Rimbaş, Roxana Cristina; Mihăilă, Sorina; Vinereanu, Dragoş

    2016-03-01

    Left atrial (LA) strain and strain rate, determined by speckle-tracking echocardiography (STE), are reproducible indices to assess LA function. Different normal ranges for LA phasic functions have been reported. We investigated the role of the reference point (P- and R-wave), gain, and region of interest (ROI), as the major sources of variation when assessing LA function. 52 subjects were evaluated for LA conventional and STE analysis. 45 of them (46 ± 14 years, 26 men) were feasible for concomitant LA deformation, and LA phasic volumes and ejection fractions (LAEF) evaluation. First, we compared the P- and R-wave methods, for the evaluation of the LA functions. We used diastolic mitral profile to clearly delineate the time intervals for each LA function. For the P-wave method, active function was assessed from negative global strain as a difference between the strain at pre-atrial contraction and strain just before mitral valve closure (GSA-), and late diastolic strain rate (GSRL); passive function from positive strain at MVO (GSA+), and from early negative diastolic strain rate (GSRE); reservoir function from the sum of GSA- and GSA+ (TGSA), and positive strain rate at the beginning of LV systole (GSR+). For the R-wave method we used the same SR parameters. The active function was evaluated by late positive global strain (GSAC), the reservoir by positive peak before the opening of the mitral valve (TGSA), and conduit function by the difference between TGSA and GSAC (GSA+). Then, by using P-wave method, we measured all previously described parameters for different gains-minimum (G0), medium (G12), and maximum (G24), and for different ROIs-minimum (ROI0), step 1 (ROI1), and 2 (ROI2). Feasibility of the LA strain measurements was 87 %. Active LA function was similar in the absolute value (GSAC and GSA-), whereas passive and reservoir functions were significantly higher (GSA+, TGSA) with the R-wave method. Active LAEF correlated with GSA- measured by the P-wave (r

  15. 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.

  16. 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.

  17. Dynamic tracking of a deformable tissue based on 3D-2D MR-US image registration

    NASA Astrophysics Data System (ADS)

    Marami, Bahram; Sirouspour, Shahin; Fenster, Aaron; Capson, David W.

    2014-03-01

    Real-time registration of pre-operative magnetic resonance (MR) or computed tomography (CT) images with intra-operative Ultrasound (US) images can be a valuable tool in image-guided therapies and interventions. This paper presents an automatic method for dynamically tracking the deformation of a soft tissue based on registering pre-operative three-dimensional (3D) MR images to intra-operative two-dimensional (2D) US images. The registration algorithm is based on concepts in state estimation where a dynamic finite element (FE)- based linear elastic deformation model correlates the imaging data in the spatial and temporal domains. A Kalman-like filtering process estimates the unknown deformation states of the soft tissue using the deformation model and a measure of error between the predicted and the observed intra-operative imaging data. The error is computed based on an intensity-based distance metric, namely, modality independent neighborhood descriptor (MIND), and no segmentation or feature extraction from images is required. The performance of the proposed method is evaluated by dynamically deforming 3D pre-operative MR images of a breast phantom tissue based on real-time 2D images obtained from an US probe. Experimental results on different registration scenarios showed that deformation tracking converges in a few iterations. The average target registration error on the plane of 2D US images for manually selected fiducial points was between 0.3 and 1.5 mm depending on the size of deformation.

  18. 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.

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

    DOE PAGES

    Makedonska, Nataliia; Painter, Scott L.; Bui, Quan M.; ...

    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

  20. 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.

  1. 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.

  2. Automatic Tracking Of Markers From 3D-Measurement Of Human Body Movements During Walking

    NASA Astrophysics Data System (ADS)

    Elsner, Thomas; Meier, G.; Baumann, Juerg U.

    1989-04-01

    For human motion analysis, the spatio-temporal resolution of cinematographic registrations of body marker positions is still higher than the results of the best opto electronic systems available for this purpose today. So far, the need for manual digitization of several thousand marker positions per tested person has made this method unpractical for regular applications. An interactive and largely automated system for marker recognition and tracking from 16 mm film images based on progress in digital image processing has been developed and tested. Projected pictures are digitized with a high-resolution CCD-camera (1320x1035 pixel), processed, analyzed and serially evaluated with an interactive image analysis system SIGNUM IS200.

  3. 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.

  4. Ultrasound speckle tracking for radial, longitudinal and circumferential strain estimation of the carotid artery--an in vitro validation via sonomicrometry using clinical and high-frequency ultrasound.

    PubMed

    Larsson, Matilda; Heyde, Brecht; Kremer, Florence; Brodin, Lars-Åke; D'hooge, Jan

    2015-02-01

    Ultrasound speckle tracking for carotid strain assessment has in the past decade gained interest in studies of arterial stiffness and cardiovascular diseases. The aim of this study was to validate and directly contrast carotid strain assessment by speckle tracking applied on clinical and high-frequency ultrasound images in vitro. Four polyvinyl alcohol phantoms mimicking the carotid artery were constructed with different mechanical properties and connected to a pump generating carotid flow profiles. Gray-scale ultrasound long- and short-axis images of the phantoms were obtained using a standard clinical ultrasound system, Vivid 7 (GE Healthcare, Horten, Norway) and a high-frequency ultrasound system, Vevo 2100 (FUJIFILM, VisualSonics, Toronto, Canada) with linear-array transducers (12L/MS250). Radial, longitudinal and circumferential strains were estimated using an in-house speckle tracking algorithm and compared with reference strain acquired by sonomicrometry. Overall, the estimated strain corresponded well with the reference strain. The correlation between estimated peak strain in clinical ultrasound images and reference strain was 0.91 (p<0.001) for radial strain, 0.73 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain and for high-frequency ultrasound images 0.95 (p<0.001) for radial strain, 0.93 (p<0.001) for longitudinal strain and 0.90 (p<0.001) for circumferential strain. A significant larger bias and root mean square error was found for circumferential strain estimation on clinical ultrasound images compared to high frequency ultrasound images, but no significant difference in bias and root mean square error was found for radial and longitudinal strain when comparing estimation on clinical and high-frequency ultrasound images. The agreement between sonomicrometry and speckle tracking demonstrates that carotid strain assessment by ultrasound speckle tracking is feasible.

  5. Speckle-tracking strain echocardiography for detecting cardiac dyssynchrony in a canine model of dyssynchrony and heart failure.

    PubMed

    Arita, Takeshi; Sorescu, George P; Schuler, Brian T; Schmarkey, Laura S; Merlino, John D; Vinten-Johansen, Jakob; Leon, Angel R; Martin, Randolph P; Sorescu, Dan

    2007-07-01

    Multiple echocardiographic criteria have been proposed to diagnose mechanical dyssynchrony in patients with heart failure without being validated against a model of cardiac dyssynchrony with heart failure. This study examines which of these methods can detect dyssynchrony in a canine model. Adult mongrel dogs underwent His-bundle ablation and right-ventricular pacing for 4 wk at either 110 bpm to induce dyssynchrony without heart failure (D group, n = 12) or 170 bpm to induce dyssynchrony with heart failure (DHF group, n = 9). To induce heart failure with narrow QRS, atria were paced at 190 bpm for 4 wk (HF group, n = 8). Tissue Doppler imaging (TDI) and two-dimensional echocardiography were performed at baseline and at end of study. Standard deviation of time to peak systolic velocity (color-coded TDI), time to peak S wave on pulse-wave TDI, time to peak radial and circumferential strain by speckle-tracking analysis (E(rr) and E(cc), respectively), and septal-to-posterior wall motion delay on M mode were obtained. In D group, only E(rr) and E(cc) were increased by dyssynchrony. In contrast, all the echocardiographic parameters of dyssynchrony appeared significantly augmented in the DHF group. Receiver-operator curve analysis showed good sensitivity of E(rr) (90%) and E(cc) (100%) to detected dyssynchrony without heart failure and excellent sensitivity and specificity of E(rr) and E(cc) to detect dyssynchrony with heart failure. Radial strain by speckle tracking is more accurate than TDI velocity to detect cardiac dyssynchrony in a canine model of dyssynchrony with or without heart failure.

  6. Assessment of myocardial function in elite athlete's heart at rest - 2D speckle tracking echocardiography in Korean elite soccer players.

    PubMed

    Eun, Lucy Youngmin; Chae, Hyun Wook

    2016-12-22

    The purpose of this study was to investigate Korean elite soccer players' myocardial function using the conventional and advanced speckle tracking imaging to compare the difference with the normal controls. We used 2D echocardiography speckle tracking echocardiography (STE) to evaluate LV regional strain in 29 elite soccer players compared to 29 age-matched healthy controls. Conventional, tissue Doppler, and STI echocardiography was performed, for strain at base and apex, rotation and torsion. There is no difference in longitudinal strain (-17.6 ± 1.8 vs -17.3 ± 2.9, p = ns), and basal radial strain. However, the significant increases were noticed in basal circumferential strain (-17.5 ± 2.6 vs -15.5 ± 8.9, p = 0.05), apical radial strain (33.1 ± 20.5 vs 22.5 ± 19.4, p = 0.02), and apical circumferential strain in soccer players (-21.4 ± 4.8 vs -16.8 ± 7.6, p = 0.005). Soccer players showed the higher rotation at base (-3.9 ± 1.9 vs -2.6 ± 3.2, p = 0.03), and apex (6.98 ± 2.62 vs 6.21 ± 3.81, p = 0.05), higher torsion (10.9 ± 3.7 vs 8.8 ± 6.3, p = 0.05). In conclusion, the elite soccer players' heart demonstrated the unique ventricular adaptation. These alterations could benefit the cardiovascular adjustment to exercise without much loss of myocardial energy expenditure.

  7. Archeological Echocardiography: Digitization and Speckle-Tracking Analysis of Archival Echocardiograms in the HyperGEN Study

    PubMed Central

    Aguilar, Frank G.; Selvaraj, Senthil; Martinez, Eva E.; Katz, Daniel H.; Beussink, Lauren; Kim, Kwang-Youn A.; Ping, Jie; Rasmussen-Torvik, Laura; Goyal, Amita; Sha, Jin; Irvin, Marguerite R.; Arnett, Donna K.; Shah, Sanjiv J.

    2015-01-01

    Background Several large epidemiologic studies and clinical trials have included echocardiography, but images were stored in analog format and these studies predated tissue Doppler imaging (TDI) and speckle-tracking echocardiography (STE). We hypothesized that digitization of analog echocardiograms, with subsequent quantification of cardiac mechanics using STE, is feasible, reproducible, accurate, and produces clinically valid results. Methods In the NHLBI HyperGEN study (N=2234), archived analog echocardiograms were digitized and subsequently analyzed using STE to obtain tissue velocities/strain. Echocardiograms were assigned quality scores and inter/intraobserver agreement was calculated. Accuracy was evaluated in (1) a separate second study (N=50) comparing prospective digital strain vs. post-hoc analog-to-digital strain; and (2) in a third study (N=95) comparing prospectively-obtained TDI e′ velocities with post-hoc STE e′ velocities. Finally, we replicated previously known associations between tissue velocities/strain, conventional echocardiographic measurements, and clinical data. Results Of the 2234 HyperGEN echocardiograms, 2150 (96.2%) underwent successful digitization and STE analysis. Inter/intraobserver agreement was high for all STE parameters, especially longitudinal strain (LS). In accuracy studies, LS performed best when comparing post-hoc STE to prospective digital STE for strain analysis. STE-derived e′ velocities correlated with, but systematically underestimated, TDI e′ velocity. Several known associations between clinical variables and cardiac mechanics were replicated in HyperGEN. We also found a novel independent inverse association between fasting glucose and LS (adjusted β =−2.4 [95% CI −3.6,−1.2]% per 1-SD increase in fasting glucose; P<0.001). Conclusions Archeological echocardiography, the digitization and speckle-tracking analysis of archival echocardiograms, is feasible and generates parameters of cardiac mechanics

  8. A GPU-accelerated 3D Coupled Sub-sample Estimation Algorithm for Volumetric Breast Strain Elastography.

    PubMed

    Peng, Bo; Wang, Yuqi; Hall, Timothy J; Jiang, Jingfeng

    2017-01-31

    Our primary objective of this work was to extend a previously published 2D coupled sub-sample tracking algorithm for 3D speckle tracking in the framework of ultrasound breast strain elastography. In order to overcome heavy computational cost, we investigated the use of a graphic processing unit (GPU) to accelerate the 3D coupled sub-sample speckle tracking method. The performance of the proposed GPU implementation was tested using a tissue-mimicking (TM) phantom and in vivo breast ultrasound data. The performance of this 3D sub-sample tracking algorithm was compared with the conventional 3D quadratic subsample estimation algorithm. On the basis of these evaluations, we concluded that the GPU implementation of this 3D sub-sample estimation algorithm can provide high-quality strain data (i.e. high correlation between the pre- and the motion-compensated post-deformation RF echo data and high contrast-to-noise ratio strain images), as compared to the conventional 3D quadratic sub-sample algorithm. Using the GPU implementation of the 3D speckle tracking algorithm, volumetric strain data can be achieved relatively fast (approximately 20 seconds per volume [2.5 cm 2.5 cm 2.5 cm]).

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

    PubMed Central

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

    2016-01-01

    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 region-of-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. PMID:27375314

  10. Reversal of left ventricular “rigid body rotation” during dipyridamole-induced stress in a patient with stable angina: a case from the three-dimensional speckle tracking echocardiographic MAGYAR-Stress Study

    PubMed Central

    Szántó, Gyula; Kalapos, Anita; Domsik, Péter; Forster, Tamás

    2016-01-01

    The left ventricular (LV) twist is defined as the wringing motion of the heart around its long-axis in systole caused by oppositely directed counterclockwise apical and clockwise basal rotations resulted from the movement of two orthogonally oriented muscular bands. In some clinical circumstances, rotation at both basal and apical levels of the LV occurred in the same clockwise or counterclockwise direction during systole resulting the near absence of LV twist as called left ventricular “rigid body rotation” (LV-RBR). Hereby we present that LV-RBR normalization of LV rotational mechanics could be demonstrated at maximum hyperaemia during dipyridamole-induced stress by three-dimensional (3D) speckle tracking echocardiography in a patient with stable angina. PMID:27429914

  11. A 3D-printed polymer micro-gripper with self-defined electrical tracks and thermal actuator

    NASA Astrophysics Data System (ADS)

    Alblalaihid, Khalid; Overton, James; Lawes, Simon; Kinnell, Peter

    2017-04-01

    This paper presents a simple fabrication process that allows for isolated metal tracks to be easily defined on the surface of 3D printed micro-scale polymer components. The process makes use of a standard low cost conformal sputter coating system to quickly deposit thin film metal layers on to the surface of 3D printed polymer micro parts. The key novelty lies in the inclusion of inbuilt masking features, on the surface of the polymer parts, to ensure that the conformal metal layer can be effectively broken to create electrically isolated metal features. The presented process is extremely flexible, and it is envisaged that it may be applied to a wide range of sensor and actuator applications. To demonstrate the process a polymer micro-scale gripper with an inbuilt thermal actuator is designed and fabricated. In this work the design methodology for creating the micro-gripper is presented, illustrating how the rapid and flexible manufacturing process allows for fast cycle time design iterations to be performed. In addition the compatibility of this approach with traditional design and analysis techniques such as basic finite element simulation is also demonstrated with simulation results in reasonable agreement with experimental performance data for the micro-gripper.

  12. 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

  13. 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.

  14. 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

  15. Left ventricular rigid body rotation in a diffuse large B-cell lymphoma patient with cardiac involvement: A case from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.

    PubMed

    Földeák, Dóra; Kalapos, Anita; Domsik, Péter; Sinkó, Mária; Szeleczki, Nóra; Bagdi, Enikő; Krenács, László; Forster, Tamás; Borbényi, Zita; Nemes, Attila

    2017-02-01

    Secondary myocardial involvement by diffuse large B-cell lymphoma is a rare occurrence. Left ventricular (LV) twist is considered an essential part of LV function. In normal circumstances LV twist results from the movement of two orthogonally oriented muscular bands of a helical myocardial structure with consequent clockwise rotation of the base and counterclockwise rotation of the apex. Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) has been found to be feasible for non-invasive 3D quantification of LV wall motion and rotational mechanics. The present report aimed to assess LV twisting motion in a patient with diffuse large B-cell lymphoma with positron emission tomography/computer tomography-proven cardiac involvement by 3DSTE. During 3DSTE, reduction in some segmental radial, longitudinal, circumferential, area and 3D LV strains were found. Apical and basal LV rotations were found to be in the same counterclockwise direction, confirming near absence of LV twist - so-called rigid body rotation.

  16. 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.

  17. 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.

  18. Intraobserver reproducibility of parameters of standard and 2D speckle tracking echocardiography, dynamics of global longitudinal strain I in patients with acute primary anterior STEMI

    NASA Astrophysics Data System (ADS)

    Kercheva, M.; Ryabova, T.; Ryabov, V.; Karpov, R.

    2015-11-01

    The aim of this study was to assess the intraobserver reproducibility of parameters of standard and 2 dimensional speckle tracking echocardiography, dynamics of global longitudinal strain in patients with acute primary anterior STEMI. The study included 24 patients, mean age 58.46±10.2. Echocardiography with 2D speckle tracking imaging was performed on the 1st (T1), 7th (T2), 14th days (T3) after STEMI («Vivid E9»). Analysis of echocardiographic images was performed offline at the different periods by the two independent observers (EchoPac) - experienced and inexperienced. In order to assess the agreement between standard and 2D speckle tracking echocardiography, a correlation analysis (Pearson correlation, Spearman's rank correlation coefficient) and Bland-Altman analysis were undertaken. The 23 patients had urgent reperfusion therapy, 6 patients underwent primary PCI, 16 patients - PCI after successful fibrinolysis (68%). GLS and WMSI had the best intraobsever reproducibility. Dynamics of EDV LV, ESV LV, EF LV was without significant differences. Nevertheless, it was found positive dynamic of GLS: - 12.65±3.53 (T1), -13.61±3.81 (T2), -14.27±4.1 (T3), p<0.05. GLS reduced 11.35% (p=0.0048) from T1 to T3. The best intraobserver reproducibility of parameters of 2 D speckle-tracking and standard echocardiography was revealed in GLS and WMSI. The modern management of STEMI patients limits adverse postinfarction remodeling and preserves of global left ventricular contractility detected by the EF LV. However, GLS had the positive dynamics and improved to the 14th day.

  19. Quantifying longitudinal right ventricular dysfunction in patients with old myocardial infarction by using speckle-tracking strain echocardiography

    PubMed Central

    2013-01-01

    Background We investigated longitudinal right ventricular (RV) function assessed using speckle-tracking strain echocardiography in patient with myocardial infarction (MI), and identified the contributing factors for RV dysfunction. Methods We retrospectively studied 71 patients with old MI (the OMI group) and 45 normal subjects (the Control group) who underwent a transthoracic echocardiography. Global and free wall RV peak systolic strains (PSSs) in the longitudinal direction were measured by using speckle-tracking strain echocardiography. Left ventricular (LV) PSSs were measured in the longitudinal, radial and circumferential directions. Cardiac hemodynamics including peak systolic pulmonary artery pressure was also assessed non-invasively. Plasma brain natriuretic peptide (BNP) levels were measured in all patients. Results In the OMI group, 73% of the patients had a normal estimated peak systolic pulmonary artery pressure of less than 35 mmHg. Global and free wall RV PSS were impaired in the OMI group compared with the Control group, and these RV systolic indices were significantly associated with heart rate, logarithmic transformed plasma BNP, greater than 1 year after onset of MI, Doppler-derived estimated pulmonary vascular resistance, LV systolic indices, LV mass index, infarcted segments within a territory of the left circumflex artery and residual total occlusion in the culprit right coronary artery. Multivariable linear regression analysis indicated that reduced longitudinal LV PSS in the 4-chamber view and BNP levels ≥500 pg/ml were independently associated with reduced global and free wall RV PSS. Moreover, when patients were divided into 3 groups according to plasma BNP levels (BNP <100 pg/ml; n = 31, 100 ≤BNP <500 pg/ml; n = 24, and BNP ≥500 pg/ml; n = 16), only patients with BNP ≥500 pg/ml had a strong correlation between RV PSS and longitudinal LV PSS in the 4-chamber view (r = 0.78 for global RV PSS and r = 0.71 for free wall RV PSS, p <0

  20. 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} .

  1. High-resolution ultrasound speckle tracking may detect vascular mechanical wall changes in peripheral artery bypass vein grafts.

    PubMed

    Weitzel, William F; Kim, Kang; Henke, Peter K; Rubin, Jonathan M

    2009-03-01

    We report the use of high-resolution, phase-sensitive ultrasound speckle tracking to measure the local vessel-wall strain in two subjects with artery-vein bypass grafts. In addition, we combined this technique with a free-hand pressure equalization procedure to elucidate the nonlinear effects of blood pressure on vessel wall compliance. While conventional ultrasound imaging can be used to elucidate the mechanical properties of tissues within the body, it is constrained by comparatively lower resolution and inferential, rather than direct, measurements of strain and by the small strain normally produced under physiological pressure in highly nonlinear structures such as arteries. One of our subjects was examined both before and after developing stenosis 3 months postsurgery. The strain values for this individual were found to be significantly lower, indicating a stiffer vessel wall at the stenotic region than at a nonstenotic region under both physiological and equalized pressure. These results suggest the possibility of noninvasive detection of neointimal hyperplasia preceding anastomotic stenosis.

  2. Longitudinal strain and strain rate by two-dimensional speckle tracking in non-sedated healthy cats.

    PubMed

    Silva, A C; Muzzi, R A L; Oberlender, G; Nogueira, R B; Muzzi, L A L; Reis, G F M; Mantovani, M M

    2013-12-01

    Two dimensional speckle tracking (2D-ST) is a relatively new tool that has been used in veterinary medicine to quantify myocardial function. However, there is little information about the use of this tool in healthy cats. Thus, the aim of this study was to evaluate left ventricular longitudinal strain and strain rate in non-sedated healthy cats, as well as longitudinal velocity and displacement, by means of 2D-ST echocardiography. Thirty non-sedated healthy cats were examined and 2D images were obtained for 2D-ST analyzes. The global mean strain and strain rate was -15.65 ± 5.46% and -1.80 ± 0.59 s(-1), respectively. Velocity and displacement were 1.41 ± 0.87 cm/s and 1.27 ± 0.80 mm, respectively. Thus, 2D-ST demonstrated to be feasible for measuring left ventricular longitudinal strain, strain rate, velocity and displacement in cats and preliminary reference values for non-sedated healthy cats can be established from the results of this study.

  3. Assessment of left ventricular longitudinal function in cats with subclinical hypertrophic cardiomyopathy using tissue Doppler imaging and speckle tracking echocardiography

    PubMed Central

    SUGIMOTO, Keisuke; FUJII, Yoko; SUNAHARA, Hiroshi; AOKI, Takuma

    2015-01-01

    Hypertrophic cardiomyopathy (HCM) in cats is characterized by concentric left ventricular (LV) hypertrophy and both diastolic and systolic dysfunction. Although impaired cardiac function detected by tissue Doppler imaging (TDI) in cats with HCM was previously reported, reference ranges of TDI in normal cats and cats with HCM have been reported as widely variable. Two-dimensional speckle tracking echocardiography (STE) was useful for assessment of cardiac function in human patients with HCM, but clinical utility was not known in cats. The aim of this study was to assess global and segmental LV myocardial function using STE in cats with HCM whose TDI variables were within the reference range. A total of 35 cats of different breeds were enrolled in this study. The HCM group (n=22) was cats diagnosed as HCM without left atrial enlargement and with normal TDI measurements. HCM cats were further divided into a segmental hypertrophy (S-HCM) group and a diffuse hypertrophy (D-HCM) group. The control group consisted of 13 clinically healthy cats. No cats in any group showed any clinical symptoms. Conventional echocardiography, TDI, and global and segmental STE indices were evaluated and compared between groups. Only the longitudinal strain rate during early diastole was significantly decreased in both HCM groups, even in all segments including those without hypertrophy in S-HCM group. This study suggests that STE parameters are the more sensitive variables compared with conventional TDI parameters to detect early myocardial diastolic dysfunction in cats with HCM. PMID:25877405

  4. Assessment of left ventricular longitudinal function in cats with subclinical hypertrophic cardiomyopathy using tissue Doppler imaging and speckle tracking echocardiography.

    PubMed

    Sugimoto, Keisuke; Fujii, Yoko; Sunahara, Hiroshi; Aoki, Takuma

    2015-09-01

    Hypertrophic cardiomyopathy (HCM) in cats is characterized by concentric left ventricular (LV) hypertrophy and both diastolic and systolic dysfunction. Although impaired cardiac function detected by tissue Doppler imaging (TDI) in cats with HCM was previously reported, reference ranges of TDI in normal cats and cats with HCM have been reported as widely variable. Two-dimensional speckle tracking echocardiography (STE) was useful for assessment of cardiac function in human patients with HCM, but clinical utility was not known in cats. The aim of this study was to assess global and segmental LV myocardial function using STE in cats with HCM whose TDI variables were within the reference range. A total of 35 cats of different breeds were enrolled in this study. The HCM group (n=22) was cats diagnosed as HCM without left atrial enlargement and with normal TDI measurements. HCM cats were further divided into a segmental hypertrophy (S-HCM) group and a diffuse hypertrophy (D-HCM) group. The control group consisted of 13 clinically healthy cats. No cats in any group showed any clinical symptoms. Conventional echocardiography, TDI, and global and segmental STE indices were evaluated and compared between groups. Only the longitudinal strain rate during early diastole was significantly decreased in both HCM groups, even in all segments including those without hypertrophy in S-HCM group. This study suggests that STE parameters are the more sensitive variables compared with conventional TDI parameters to detect early myocardial diastolic dysfunction in cats with HCM.

  5. Evaluation of right atrial function by two-dimensional speckle-tracking echocardiography in patients with right ventricular myocardial infarction.

    PubMed

    Nourian, Saeed; Hosseinsabet, Ali; Jalali, Arash; Mohseni-Badalabadi, Reza

    2017-01-01

    Right ventricular myocardial infarction (RVMI) damages the systolic and diastolic functions of the RV, so the right atrium interacts with the RV with an acutely altered function. The aim of our study was to compare right atrial function as evaluated by 2D speckle-tracking echocardiography (2DSTE) between patients with inferior wall myocardial infarction (INFMI) and patients affected by both inferior myocardial infarction and right ventricular myocardial infarction (INFMI + RVMI). Our study recruited 70 consecutive patients with INFMI (43 patients without RVMI and 27 patients with RVMI). Right atrial function was evaluated by 2DSTE. Early diastolic strain, systolic strain rate, absolute value of early diastolic strain rate, expansion index, and diastolic emptying index of the right atrium were reduced in the patients with INFMI + RVMI compared to the patients with INFMI. The area under the curve for early diastolic strain for INFMI diagnosis was 0.682 (p value = 0.011, 95 % CI 0.550-0.815). Right atrial early diastolic longitudinal strain <27.5 % had 59.3 % sensitivity and 79.1 % specificity for the discrimination of INFMI + RVMI from INFMI. Our results demonstrated that right atrial reservoir and conduit functions were impaired in the patients with INFMI + RVMI compared with the patients with INFMI.

  6. Towards pointwise motion tracking in echocardiographic image sequences--comparing the reliability of different features for speckle tracking.

    PubMed

    Yu, Weichuan; Yan, Ping; Sinusas, Albert J; Thiele, Karl; Duncan, James S

    2006-08-01

    In this paper, we studied the problem of feature-based motion tracking in echocardiographic image sequences. We described the relation between possible feature variations and different kinds of tissue motion using a linear convolution model. We also showed that motion-feature decorrelation (which means that the motion parameters estimated using feature tracking fail to represent the underlying tissue motion) compensation is an ill-posed inverse problem. Instead of finding a method that may provide better compensation results than previous approaches, we used an quantitative measure to compare the reliability of tracking features. Experiment results showed that the use of the reliability measure improved the robustness of displacement estimation. With the help of the reliability measure, we compared the performance of different features using simulations and phantom examples. While we noticed that the radio frequency (RF) signal outperforms the B-mode (BM) signal in the analysis of small deformation (e.g., less than 0.1% compression), we also found out that the BM signal works better than the RF signal in the analysis of large deformation (e.g., larger than 2% compression). The use of a band-passed filtered feature does not result in significant improvement in tracking.

  7. SU-D-210-05: The Accuracy of Raw and B-Mode Image Data for Ultrasound Speckle Tracking in Radiation Therapy

    SciTech Connect

    O’Shea, T; Bamber, J; Harris, E

    2015-06-15

    Purpose: For ultrasound speckle tracking there is some evidence that the envelope-detected signal (the main step in B-mode image formation) may be more accurate than raw ultrasound data for tracking larger inter-frame tissue motion. This study investigates the accuracy of raw radio-frequency (RF) versus non-logarithmic compressed envelope-detected (B-mode) data for ultrasound speckle tracking in the context of image-guided radiation therapy. Methods: Transperineal ultrasound RF data was acquired (with a 7.5 MHz linear transducer operating at a 12 Hz frame rate) from a speckle phantom moving with realistic intra-fraction prostate motion derived from a commercial tracking system. A normalised cross-correlation template matching algorithm was used to track speckle motion at the focus using (i) the RF signal and (ii) the B-mode signal. A range of imaging rates (0.5 to 12 Hz) were simulated by decimating the imaging sequences, therefore simulating larger to smaller inter-frame displacements. Motion estimation accuracy was quantified by comparison with known phantom motion. Results: The differences between RF and B-mode motion estimation accuracy (2D mean and 95% errors relative to ground truth displacements) were less than 0.01 mm for stable and persistent motion types and 0.2 mm for transient motion for imaging rates of 0.5 to 12 Hz. The mean correlation for all motion types and imaging rates was 0.851 and 0.845 for RF and B-mode data, respectively. Data type is expected to have most impact on axial (Superior-Inferior) motion estimation. Axial differences were <0.004 mm for stable and persistent motion and <0.3 mm for transient motion (axial mean errors were lowest for B-mode in all cases). Conclusions: Using the RF or B-mode signal for speckle motion estimation is comparable for translational prostate motion. B-mode image formation may involve other signal-processing steps which also influence motion estimation accuracy. A similar study for respiratory-induced motion

  8. Spatial and temporal properties of speckle interferograms

    NASA Astrophysics Data System (ADS)

    Weigelt, G. P.

    1980-12-01

    In order to investigate the spatial structure of a three-dimensional speckle intensity distribution, we have studied the intensity correlation function of two arbitrary points in a 3-D-speckle field. The result is an extension of the lateral autocorrelation function of speckle interferograms first derived by L. I. Goldfischer. Speckle interferograms will fluctuate temporally if the random object (rough surface or air turbulence) varies in time. The temporal properties of speckle interferograms are important for various applications. Therefore we have developed a method for measuring the ''life time'' of speckles. We record the temporal behaviour of the speckles with a 16mm-movie camera. The life time is determining by measuring the average crosscorrelation of adjacent frames on the 16mm-motion picture films. We used this method to measure the life time of stellar speckle interferograms. Based on these studies it was possible to perform speckle interferometry measurements of rather faint astronomical objects.

  9. Surface profile acquisition using dynamic speckles

    NASA Astrophysics Data System (ADS)

    Semenov, Dmitry V.; Nippolainen, Ervin; Raita, Erik; Kamshilin, Alexei A.

    2006-01-01

    In this work we present the novel technique for z-distance measurement to an optically rough surface using dynamic speckles. The technique is based on the continuous frequency measurements of the power modulation of the spatially filtered scattered light. The dynamic speckle pattern is created when the laser beam scans the surface under study. The complete optical-electronic system was designed and fabricated for fast measurement of the speckles velocity, its recalculation into the distance, and further data acquisition into computer. The measured surface profile is displayed in a PC monitor in real time. Main advantage of the proposed technique is high scanning speed providing an extremely short response time below 1 μs. Important parameters of the system such as accuracy, range of measurements, and spatial resolution are analyzed. Limits of the spatial filtering technique used for continuous tracking of the speckle-pattern velocity are shown. Possible ways of further improvement of the measurements accuracy are demonstrated. Due to its extremely fast operation the proposed technique could find applications in such areas as online quality control of materials (paper thickness, rolled metal roughness, etc.) moving on production lines with high velocities (up to 20 m/s) or online control of the 3D-shape of complex objects (e.g., electronic circuits) during their assembling.

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

    PubMed

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

    2012-12-21

    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

  11. 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

  12. Crosstalk minimization in autostereoscopic multiveiw 3D display by eye tracking and fusion (overlapping) of viewing zones

    NASA Astrophysics Data System (ADS)

    Kim, Sung-Kyu; Yoon, Seon-Kyu; Yoon, Ki-Hyuk

    2012-06-01

    An autostereoscopic 3D display provides the binocular perception without eye glasses, but induces the low 3D effect and dizziness due to the crosstalk effect. The crosstalk related problems give the deterioration of 3D effect, clearness, and reality of 3D image. A novel method of reducing the crosstalk is designed and tested; the method is based on the fusion of viewing zones and the real time eye position. It is shown experimentally that the crosstalk is effectively reduced at any position around the optimal viewing distance.

  13. Two-dimensional speckle-tracking echocardiography assessment of left ventricular remodeling in patients after myocardial infarction and primary reperfusion

    PubMed Central

    Haberka, Maciej; Tabor, Zbigniew; Finik, Maciej; Gąsior, Zbigniew

    2014-01-01

    Introduction Left ventricular remodeling (LVR) is the most prognostically important consequence of acute myocardial infarction (AMI). The aim of the study was to assess the value of speckle tracking echocardiography in the prediction of left ventricular remodeling in patients after AMI and primary coronary angioplasty (PCI). Material and methods Eighty-eight patients (F/M = 31/57 patients; 63.6 ±11 years old) with coronary artery disease (CAD) and successful PCI were enrolled and divided into group I with ST-elevation myocardial infarction or non-ST elevation myocardial infarction and group II with stable angina pectoris. Conventional and speckle tracking echocardiography was performed 3 days (baseline), 30 days and 90 days after PCI. Patients were divided into 2 groups based on the presence of LVR (increase of LV end-diastolic and/or end-systolic volume > 20%) at 3 months follow-up. Results At initial presentation, 2-chamber longitudinal strain (9.4 ±3.5% vs. –11.6 ±3.6%, p < 0.04) and 4-chamber transverse strain (10.4 ±8.2% vs. 15.6 ±8%, p < 0.003) were lower in the LVR+ group compared to the LVR– group. LV wall motion score index did not differ between the two groups. After 30 days, circumferential apical and basal strain (–15.58 ±8.9% vs. –25.53 ±8.8%, p < 0.001; –15.02 ±5.6 vs. –19.78 ±6.3, p < 0.008), radial apical strain (9.96 ±8.4% vs. 14.15 ±5.5%, p < 0.03), 4-chamber longitudinal strain (–8.7 ±5.8% vs. –13.47 ±3.9%, p < 0.005), 4-chamber transverse strain (10.5 ±8.1% vs. 16.7 ±8.3%, p < 0.03), apical rotation (3.84 ±2.5° vs, 5.66 ±3.2°, p < 0.04) and torsion (6.15 ±4.1° vs. 8.98 ±4.6°, p < 0.03) were significantly decreased in the LVR+ group compared to the LVR– group. According to ROC analysis, circumferential apical strain > –15.92% (sensitivity 93%, specificity 59%, positive predictive value 90%) was the most powerful predictor of remodeling after primary PCI in AMI. Conclusions Our results suggest that

  14. 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.

  15. Effects of anesthesia on conventional and speckle tracking echocardiographic parameters in a mouse model of pressure overload

    PubMed Central

    WANG, GUAN; ZHANG, LE; MANYANDE, ANNE; CAO, MING; HE, WEI; WU, XIAOFEN; WANG, JINLI; ZHANG, CUNTAI

    2015-01-01

    Genetically-modified mice are widely applied in cardiovascular studies as model organisms. Echocardiography is a key tool for evaluating cardiac and hemodynamic functions in mice. The present study aimed to examine the effects of isoflurane (ISF) on conventional and speckle tracking echocardiography (STE) parameters under healthy and pathological conditions using a murine model of pressure overload. In addition, the optimal dose of ISF in the process of echocardiographic measurement, with minimum cardiac contraction depression, was investigated. Conventional echocardiographic and STE examinations were performed on 38 adult C57BL/6 male mice. The mice were divided into the following three groups: The sham (n=15); mild thoracic aortic banding (TAB; n=15); and severe TAB (n=8) groups. ISF was administered under deep anesthesia (DA; 1–2% ISF), light anesthesia (LA; 0.5–1% ISF) and immediately prior to the mice waking up (awake; 0–0.5% ISF). Conventional echocardiographic parameters were preserved within the sham and mild TAB groups (P>0.05 for each parameter) under LA and awake conditions. However, under DA conditions, the majority of these parameters were reduced compared with the LA and awake conditions (P<0.05). In the severe TAB group, conventional echocardiographic parameters remained constant under LA, DA and awake conditions. STE parameters in the groups remained similar between the LA and awake conditions, but were significantly reduced under DA conditions. Therefore, conventional echocardiography and STE may be performed using LA induced with low doses of ISF, under various pathological conditions without affecting cardiac function. PMID:26136877

  16. Evaluation of right ventricle by speckle tracking and conventional echocardiography in rats with right ventricular heart failure.

    PubMed

    Kimura, Koichi; Daimon, Masao; Morita, Hiroyuki; Kawata, Takayuki; Nakao, Tomoko; Okano, Tomoko; Lee, Seitetsu L; Takenaka, Katsu; Nagai, Ryozo; Yatomi, Yutaka; Komuro, Issei

    2015-05-13

    Speckle tracking echocardiography (STE) has been reported to be a promising technique for evaluating right ventricular (RV) function in the clinical setting. On the other hand, the usefulness of STE for RV evaluation in small animal models has not been clarified, although the rat model is among the most commonly used animal models to develop novel effective treatments against pulmonary hypertension and RV heart failure (HF).We validated the use of STE and conventional echocardiographic variables for evaluating RV functions in a rat model by comparing the echocardiographic values of RVHF rats (n = 12) induced by monocrotaline injection with those of control rats (n = 12).Most conventional echocardiographic variables demonstrated that RVHF rats have significant RV dysfunction. The area under the curve (AUC) values to distinguish RV dysfunction in RVHF rats from normal RV function in control rats using fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), RV myocardial performance index (MPI), peak tissue Doppler tricuspid annular velocities at systole (Sa), and at early diastole (Ea) were 0.71, 0.98, 0.79, 0.92, and 0.91, respectively. However, using STE analysis for RV evaluation, limited reproducibility was observed (variability 19-37 %, ICC 0.74-0.88) and the only circumferential strain showed significantly lower absolute values (P = 0.039, AUC = 0.76).To evaluate RV function in rat models, circumferential strain may be useful, however, the reproducibility and diagnostic utility were limited. Conventional echocardiographic variables such as TAPSE, tissue Doppler Sa, and Ea have superior diagnostic utility.

  17. Layer-specific strain analysis by speckle tracking echocardiography reveals differences in left ventricular function between rats and humans.

    PubMed

    Bachner-Hinenzon, Noa; Ertracht, Offir; Leitman, Marina; Vered, Zvi; Shimoni, Sara; Beeri, Ronen; Binah, Ofer; Adam, Dan

    2010-09-01

    The rat heart is commonly used as an experimental model of the human heart in both health and disease states, assuming that heart function of rats and humans is alike. When studying a rat model, echocardiography is usually performed on sedated rats, whereas standard echocardiography on adult humans does not require any sedation. Since echocardiography results of sedated rats are usually inferred to alert humans, in the present study, we tested the hypothesis that differences in left ventricular (LV) function may be present between rats sedated by a low dose of ketamine-xylazine and alert humans. Echocardiography was applied to 110 healthy sedated rats and 120 healthy alert humans. Strain parameters were calculated from the scans using a layer-specific speckle tracking echocardiography program. The results showed that layer longitudinal strain is equal in rats and humans, whereas segmental strain is heterogeneous (P < 0.05) in a different way in rats and humans (P < 0.05). Furthermore, layer circumferential strain is larger in humans (P < 0.001), and the segmental results showed different segmental heterogeneity in rats and humans (P < 0.05). Radial strain was found to be homogeneous at the apex and papillary muscle levels in humans and heterogeneous in rats (P < 0.001). Additionally, whereas LV twist was equal in rats and humans, in rats the rotation was larger at the apex (P < 0.01) and smaller at the base (P < 0.001). The torsion-to-shortening ratio parameter, which indicates the transmural distribution of contractile myofibers, was found to be equal in rats and humans. Thus, when evaluating LV function of sedated rats under ketamine-xylazine, it is recommended to measure the global longitudinal strain, LV twist, and torsion-to-shortening ratio, since no scaling is required when converting these parameters and inferring them to humans.

  18. Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

    PubMed Central

    2010-01-01

    Background The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions. Methods This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization) to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus. Results Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values. Conclusions Since pressure equalization may increase the dynamic range of strain imaging, the effect of the surrounding tissue on strain should

  19. Evaluation of Myocardial Function in Patients with Rheumatoid Arthritis Using Strain Imaging by Speckle-Tracking Echocardiography

    PubMed Central

    Fine, Nowell M.; Crowson, Cynthia S.; Lin, Grace; Oh, Jae K.; Villarraga, Hector R.; Gabriel, Sherine E.

    2014-01-01

    Objectives Patients with rheumatoid arthritis (RA) are at increased risk for cardiovascular disease (CVD), although strategies to detect sub-clinical CVD are poorly characterized. The purpose of this study was to assess myocardial function by speckle-tracking echocardiography strain imaging in RA patients without known CVD. Methods Eighty-seven RA patients selected from a population-based sample underwent echocardiography. Left (LV) and right ventricular (RV) longitudinal peak systolic strain were measured. A subset of 59 RA patients was compared with 59 age, gender and race-matched subjects with normal echocardiography and no CVD or risk factors. Results The mean age of matched RA and normal patients was 55.7±12.1 and 54.5±12.2 years (p=0.42), respectively, and 45 (76%) were female in each group. Global LV (−15.7 ±3.2% versus −18.1 ±2.4%, p<0.001) and RV strain (−17.9 ± 4.7% versus −20.7±2.4%, p<0.001) were reduced in RA patients compared to normal patients. Among all 87 RA patients, the mean disease duration and C-reactive protein at echocardiography were 10.0±6.1 years and 3.5±3.7 mg/L, and 74% were seropositive. Adjusted univariate regression analysis demonstrated a significant correlation between global LV strain and RA health assessment questionnaire disability index (p=0.032), and borderline associations with prior use of oral corticosteroids (p=0.062) and methotrexate (p=0.054) after adjustment for age, gender, blood pressure, body mass index, heart rate and LV mass index. Conclusions Global longitudinal LV and RV strain were reduced in RA patients compared with healthy patients. Strain abnormalities correlated with RA disease severity. Strain imaging by echocardiography may detect early myocardial dysfunction in RA. PMID:23873875

  20. Regional left atrial function differentiation in patients with constrictive pericarditis and restrictive cardiomyopathy: a study using speckle tracking echocardiography.

    PubMed

    Liu, Shuang; Ma, Chunyan; Ren, Weidong; Zhang, Jing; Li, Nan; Yang, Jun; Zhang, Yan; Qiao, Wei

    2015-12-01

    Left atrial (LA) function plays an important role in the maintenance of cardiac output. However, whether assessment of regional LA myocardial dysfunction is useful for differentiating between CP and restrictive cardiomyopathy (RCM) remains unclear. Thirty-five patients with CP, 30 patients with RCM, and 30 healthy volunteers (controls) were enrolled in this study. The LA maximum volume (Vmax), LA minimal volume (Vmin), and LA volume before atrial contraction (Vpre-a) were measured using the biplane modified Simpson's rule. All patients underwent two-dimensional speckle tracking echocardiography (STE). The peak systolic strain rate (SrS), early diastolic strain rate (SrE), and late diastolic strain rate (SrA) of the LA septum, LA lateral wall and superior walls were measured. The LA diastolic and systolic function was found to be reduced in patients with CP and RCM. The SrE in the LA superior wall and lateral wall were significantly decreased in patients with CP and RCM compared with controls (P < 0.001). The SrE of the LA septum in patients with CP was preserved compared to normal controls. Althouth the LA septal SrE in patients with CP was significantly reduced (P < 0.001). For the diagnosis of RCM, a cutoff value 1.40 for SrE of the LA septum showed a sensitivity of 94.7 % and a specificity of 89.7 %. The SrE in the LA superior wall and lateral wall were decreased while the LA septal SrE was preserved in patients with CP, indicating that the rigid pericardium might restrict myocardial motion and deformation in the lateral wall. The measurement of STE to determine the LA septal SrE can be helpful for differentiating between CP and RCM.

  1. Left ventricular adaptation to high altitude: speckle tracking echocardiography in lowlanders, healthy highlanders and highlanders with chronic mountain sickness.

    PubMed

    Dedobbeleer, Chantal; Hadefi, Alia; Pichon, Aurelien; Villafuerte, Francisco; Naeije, Robert; Unger, Philippe

    2015-04-01

    Hypoxic exposure depresses myocardial contractility in vitro, but has been associated with indices of increased cardiac performance in intact animals and in humans, possibly related to sympathetic nervous system activation. We explored left ventricular (LV) function using speckle tracking echocardiography and sympathetic tone by spectral analysis of heart rate variability (HRV) in recently acclimatized lowlanders versus adapted or maladapted highlanders at high altitude. Twenty-six recently acclimatized lowlanders, 14 healthy highlanders and 12 highlanders with chronic mountain sickness (CMS) were studied. Control measurements at sea level were also obtained in the lowlanders. Altitude exposure in the lowlanders was associated with slightly increased blood pressure, decreased LV volumes and decreased longitudinal strain with a trend to increased prevalence of post-systolic shortening (p = 0.06), whereas the low frequency/high frequency (LF/HF) ratio increased (1.62 ± 0.81 vs. 5.08 ± 4.13, p < 0.05) indicating sympathetic activation. Highlanders had a similarly raised LF/HF ratio, but no alteration in LV deformation. Highlanders with CMS had no change in LV deformation, no significant increase in LF/HF, but decreased global HRV still suggestive of increased sympathetic tone, and lower mitral E/A ratio compared to healthy highlanders. Short-term altitude exposure in lowlanders alters indices of LV systolic function and increases sympathetic nervous system tone. Life-long altitude exposure in highlanders is associated with similar sympathetic hyperactivity, but preserved parameters of LV function, whereas diastolic function may be altered in those with CMS. Altered LV systolic function in recently acclimatized lowlanders may be explained by combined effects of hypoxia and changes in loading conditions.

  2. The prognostic value of standardized reference values for speckle-tracking global longitudinal strain in hypertrophic cardiomyopathy.

    PubMed

    Hartlage, Gregory R; Kim, Jonathan H; Strickland, Patrick T; Cheng, Alan C; Ghasemzadeh, Nima; Pernetz, Maria A; Clements, Stephen D; Williams, B Robinson

    2015-03-01

    Speckle-tracking left ventricular global longitudinal strain (GLS) assessment may provide substantial prognostic information for hypertrophic cardiomyopathy (HCM) patients. Reference values for GLS have been recently published. We aimed to evaluate the prognostic value of standardized reference values for GLS in HCM patients. An analysis of HCM clinic patients who underwent GLS was performed. GLS was defined as normal (more negative or equal to -16%) and abnormal (less negative than -16%) based on recently published reference values. Patients were followed for a composite of events including heart failure hospitalization, sustained ventricular arrhythmia, and all-cause death. The power of GLS to predict outcomes was assessed relative to traditional clinical and echocardiographic variables present in HCM. 79 HCM patients were followed for a median of 22 months (interquartile range 9-30 months) after imaging. During follow-up, 15 patients (19%) met the primary outcome. Abnormal GLS was the only echocardiographic variable independently predictive of the primary outcome [multivariate Hazard ratio 5.05 (95% confidence interval 1.09-23.4, p = 0.038)]. When combined with traditional clinical variables, abnormal GLS remained independently predictive of the primary outcome [multivariate Hazard ratio 5.31 (95 % confidence interval 1.18-24, p = 0.030)]. In a model including the strongest clinical and echocardiographic predictors of the primary outcome, abnormal GLS demonstrated significant incremental benefit for risk stratification [net reclassification improvement 0.75 (95 % confidence interval 0.21-1.23, p < 0.0001)]. Abnormal GLS is an independent predictor of adverse outcomes in HCM patients. Standardized use of GLS may provide significant incremental value over traditional variables for risk stratification.

  3. Utility of comprehensive assessment of strain dyssynchrony index by speckle tracking imaging for predicting response to cardiac resynchronization therapy.

    PubMed

    Tatsumi, Kazuhiro; Tanaka, Hidekazu; Yamawaki, Kouhei; Ryo, Keiko; Omar, Alaa Mabrouk Salem; Fukuda, Yuko; Norisada, Kazuko; Matsumoto, Kensuke; Onishi, Tetsuari; Gorcsan, John; Yoshida, Akihiro; Kawai, Hiroya; Hirata, Ken-ichi

    2011-02-01

    The strain delay index is reportedly a marker of dyssynchrony and residual myocardial contractility. The aim of this study was to test the hypothesis that a relatively simple version of the strain dyssynchrony index (SDI) can predict response to cardiac resynchronization therapy (CRT) and that combining assessment of radial, circumferential, and longitudinal SDI can further improve the prediction of responders. A total of 52 patients who underwent CRT were studied. The SDI was calculated as the average difference between peak and end-systolic strain from 6 segments for radial and circumferential SDI and 18 segments for longitudinal SDI. Conventional dyssynchrony measures were assessed by interventricular mechanical delay, the Yu index, and radial dyssynchrony by speckle tracking strain. Response was defined as a ≥15% decrease in end-systolic volume after 3 months. Of the individual parameters, radial SDI ≥6.5% was the best predictor of response to CRT, with sensitivity of 81%, specificity of 81%, and an area under the curve of 0.87 (p <0.001). Circumferential SDI ≥3.2% and longitudinal SDI ≥3.6% were also found to be predictive of response to CRT, with areas under the curve of 0.81 and 0.80, respectively (p <0.001). Moreover, radial, circumferential, and longitudinal SDI at baseline were correlated with reduction of end-systolic volume with CRT. In addition, the response rate in patients with 3 positive SDIs was 100%. In contrast, rates in patients with either 1 or no positive SDIs were 42% and 22%, respectively (p <0.005 and p <0.001 vs 3 positive SDIs). In conclusion, the SDI can successfully predict response to CRT, and the combined approach leads to more accurate prediction than using individual parameters.

  4. Three-dimensional motion measurements using feature tracking.

    PubMed

    Kuo, Johnny; von Ramm, Olaf T

    2008-04-01

    Feature tracking was developed to efficiently compute motion measurements from volumetric ultrasound images. Prior studies have demonstrated the motion magnitude accuracy and computation speed of feature tracking. However, the previous feature tracking implementations were limited by performance of their calculations in rectilinear coordinates. Also, the previous feature tracking approaches did not fully explore the three dimensional (3- D) nature of volumetric image analysis or utilize the 3-D directional information from the tracking calculations. This study presents an improved feature tracking method which achieves further computation speed gains by performing all calculations in the native spherical coordinates of the 3-D ultrasound image. The novel method utilizes a statistical analysis of tracked directions of motion to achieve better rejection of false tracking matches. Results from in vitro tracking of a speckle target show that the new feature tracking method is significantly faster than correlation search and can accurately determine target motion magnitude and 3-D direction.

  5. Speckle tracking echocardiography in the critically ill: enticing research with minimal clinical practicality or the answer to non-invasive cardiac assessment?

    PubMed

    Orde, S; Huang, S J; McLean, A S

    2016-09-01

    Echocardiography is developing rapidly. Speckle tracking echocardiography is the latest semi-automatic tool that has potential to quantitatively describe cardiac dysfunction that may be unrecognised by conventional echocardiography. It is a non-Doppler, angle-independent, feasible and reproducible method to evaluate myocardial function in both non-critically ill and critically ill populations. Increasingly it has become a standard measure of both left and right ventricle function in specific patient groups, e.g. chemotherapy-induced cardiomyopathy or pulmonary hypertension. To date there are few studies in the critically ill, predominantly in sepsis, yet all describe dysfunction beyond standard measures. Other areas of interest include heart-lung interactions, right ventricle function and twist and torsion of the heart. A word of caution is required, however, in that speckle tracking echocardiography is far from perfect and is more challenging, particularly in the critically ill, than implied by many published studies. It takes time to learn and perform and most values are not validated, particularly in the critically ill. We should be cautious in accepting that the latest software used in cardiology cohorts will automatically be the answer in the critically ill. Even with these limitations the technology is enticing and results fascinating. We are uncovering previously undescribed dysfunction and although it currently is essentially a research-based activity, there is great promise as a clinical tool as echocardiography analysis becomes more automated, and potentially speckle tracking echocardiography could help describe cardiac function in critical illness more accurately than is possible with current techniques.

  6. 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.

  7. Real-Time, Multiple, Pan/Tilt/Zoom, Computer Vision Tracking, and 3D Position Estimating System for Unmanned Aerial System Metrology

    DTIC Science & Technology

    2013-10-18

    area of 3D point estimation of flapping- wing UASs. The benefits of designing and developing such a system is instrumental in researching various...are many benefits to us- ing SIFT in tracking. It detects features that are invariant to image scale and rotation, and are shown to provide robust...provided to estimate background motion for optical flow background subtraction. The experiments with the static background showed minute benefit in

  8. Two-Dimensional Speckle Tracking Echocardiography Predict Left Ventricular Remodeling after Acute Myocardial Infarction in Patients with Preserved Ejection Fraction

    PubMed Central

    Hsiao, Ju-Feng; Chung, Chang-Min; Chu, Chi-Ming; Lin, Yu-Shen; Pan, Kuo-Li; Chang, Shih-Tai

    2016-01-01

    Objectives Left ventricular remodeling after acute myocardial infarction increases cardiovascular events and mortality. But few study was done in patients with preserved ejection fraction (EF > 40%). We investigate whether the strain and strain rate by 2D speckle tracking echocardiography could predict left ventricular remodeling after acute myocardial infarction in this cohort. Methods The 83 patients (average age 60.7 ± 12.3 y, 75 [90.4%] male) with new-onset acute myocardial infarction receiving echocardiography immediately, and 6 months after admission were grouped by the presence or absence of left ventricular remodeling. Strain and strain rate including longitudinal, circumferential, and radial direction were calculated. The average of strain and strain rate of which segmental longitudinal strains > – 15% were defined as the injury longitudinal strain (InjLS). Results Left ventricular remodeling occurred in 24 of 83 patients (28.9%). In univariate logistic regression analyses, gender, peak CK-MB, log BNP, use of statin before discharge, wall motion score index, and InjLS were significantly associated with left ventricular remodeling (p < 0.05). In multivariate analysis using the forward stepwise method, gender, CK-MB, and InjLS were independent predictors. The hazard ratio for InjLS was 1.48 (p = 0.04). Receiver operating characteristic curve (ROC) analyses showed the area under the curve (AUC) of InjLS was largest (AUC = 0.75, cut-off value = –11.7%, sensitivity = 81%, specificity = 71%, p < 0.01). In ST-segment elevation myocardial infarction subgroup, InjLS was the only predictor according to ROC analysis (AUC = 0.79, p < 0.01, cut-off value = –11.4%, sensitivity = 88%, specificity = 77%) and multivariate logistic regression analysis (hazard ratio = 1.88, 95% CI: 1.22–2.88, p < 0.01). Conclusions InjLS was an excellent predictor for left ventricular remodeling after acute myocardial infarction in patient with preserved ejection fraction. PMID

  9. [Assessment right atrial function in patients with systemic lupus erythematosus by speckle tracking and three-dimensional echocardiography].

    PubMed

    Ge, X Y; Shao, L; Zheng, Z L

    2016-12-20

    Objective: To evaluate right atrial function in systemic lupus erythematosus (SLE) with normal pulmonary pressure by using two dimensional-speckle tracking imaging (2D-STI) and real-time three-dimensional echocardiography(RT-3DE). Methods: A totoal of 40 patients with SLE and 40 control subjects were collected between December 2011 and May 2014 from Ningbo Medical Treatment Center Lihuili Hospital. Right atrial global longitudinal strain (RAGLS) and all kinds of right atrium volume index (RAVI) were detected. Relationship between tricuspid annular plane systolic excursion(TAPSE), tricuspid annulus systolic peak velocity (S'), right ventricular myocardial performance index (RVMPI), ETV/e'TV and the right atrium parameters were analyzed. Results: SLE group's right atrium maximal volume index(RAVImax)(33.5±11.1) ml/m(2,) right atrium minimal volume index (RAVImin)(13.2±4.5) ml/m(2,) right atrium presystolic volume index (RAVIpre) (2.57±10.2) ml/m(2,) right atrium total emptying volume index(RAVIt)(20.2±8.1)ml/m(2,) right atrium active emptying volume index (RAVIa)(12.5±7.5) ml/m(2)) were increased .But right atrium passive emptying volume index(RAVIp)( 7.8±2.7) ml/m(2) and right atrial global longitudinal strain (RAGLS) (38.2%±7.7% ) were decreased (both P<0.05). RAGLS was positive correlated with S' and TAPSE, the r value were 0.565 and 0.445 respectively (both P<0.01). ETV/e'TV was positive correlated with RAVIpre, RAVIa, the r value were 0.469 and 0.481 respectively (both P<0.05). Conclusion: Detecting right atrial function by 2D-STI and RT-3DE could diagnose right atrial dysfunction in early stage of SLE patients with normal pulmonary pressure. The method is simple, has significant clinical value.

  10. Normal and shear strains of the left ventricle in healthy human subjects measured by two-dimensional speckle tracking echocardiography

    PubMed Central

    2014-01-01

    Background Animal studies have shown that shear deformation of myocardial sheets in transmural planes of left ventricular (LV) wall is an important mechanism for systolic wall thickening, and normal and shear strains of the LV free wall differ from those of the interventricular septum (IVS). We sought to test whether these also hold for human hearts. Methods Thirty healthy volunteers (male 23 and female 7, aged 34 ± 6 years) from Outpatient Department of the University of Tokyo Hospital were included. Echocardiographic images were obtained in the left decubitus position using a commercially available system (Aloka SSD-6500, Japan) equipped with a 3.5-MHz transducer. The ECG was recorded simultaneously. The peak systolic radial normal strain (length change), shear strain (angle change) and time to peak systolic radial normal strain were obtained non-invasively by two-dimensional speckle tracking echocardiography. Results The peak systolic radial normal strain in both IVS and LV posterior wall (LVPW) showed a trend to increase progressively from the apical level to the basal level, especially at short axis views, and the peak systolic radial normal strain of LVPW was significantly greater than that of IVS at all three levels. The time to peak systolic radial normal strain was the shortest at the basal IVS, and increased progressively from the base to the apical IVS. It gradually increased from the apical to the basal LVPW in sequence, especially at short axis views. The peak of radial normal strain of LVPW occurred much later than the peak of IVS at all three levels. For IVS, the shear deformation was clockwise at basal level, and counterclockwise at mid and apical levels in LV long-axis view. For LVPW, the shear deformations were all counterclockwise in LV long-axis view and increased slightly from base to the apex. LVPW showed larger shear strains than IVS at all three levels. Bland-Altman analysis shows very good agreement between measurements taken by the

  11. 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

  12. 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.

  13. 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

  14. Evaluation of Performance of a Maximum Likelihood Estimator for Tracking Purposes in the Presence of Speckle Noise

    DTIC Science & Technology

    2009-03-01

    as the detector moves away from the source. However, we can rarely neglect diffraction effects and the mea- sured intensity takes the form of Iθ = Iθ(0...earlier (although not known as speckle at the time), by Verdet (1865) and Lord Rayleigh (1880) in their work on Fraunhofer rings. Von Laue [14–16] derived

  15. 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.

  16. 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

  17. 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.

  18. 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

  19. Progress in high temperature speckle-shift strain measurement system

    NASA Technical Reports Server (NTRS)

    Lant, Christian T.; Barranger, John P.

    1990-01-01

    A fast, easy to use speckle tracking system is under development for the speckle-shift strain measurement technique. Preliminary correlation tests on wire specimens show strong correlations of well-developed speckle patterns. Stable cross-correlations were obtained from a tungsten filament at 2480 C. An analysis of the optical system determines the minimum required sampling frequency of the speckle pattern to be 2.55 pixels per speckle.

  20. 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

  1. 3D visualisation of the stochastic patterns of the radial dose in nano-volumes by a Monte Carlo simulation of HZE ion track structure.

    PubMed

    Plante, Ianik; Ponomarev, Artem; Cucinotta, Francis A

    2011-02-01

    The description of energy deposition by high charge and energy (HZE) nuclei is of importance for space radiation risk assessment and due to their use in hadrontherapy. Such ions deposit a large fraction of their energy within the so-called core of the track and a smaller proportion in the penumbra (or track periphery). We study the stochastic patterns of the radial dependence of energy deposition using Monte Carlo track structure codes RITRACKS and RETRACKS, that were used to simulate HZE tracks and calculate energy deposition in voxels of 40 nm. The simulation of a (56)Fe(26+) ion of 1 GeV u(-1) revealed zones of high-energy deposition which maybe found as far as a few millimetres away from the track core in some simulations. The calculation also showed that ∼43 % of the energy was deposited in the penumbra. These 3D stochastic simulations combined with a visualisation interface are a powerful tool for biophysicists which may be used to study radiation-induced biological effects such as double strand breaks and oxidative damage and the subsequent cellular and tissue damage processing and signalling.

  2. 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.

  3. 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.

  4. Are changes in the extent of left ventricular dyssynchrony as assessed by speckle tracking associated with response to cardiac resynchronization therapy?

    PubMed

    Ghani, Abdul; Delnoy, Peter Paul H M; Ottervanger, Jan Paul; Ramdat Misier, Anand R; Smit, Jaap Jan J; Adiyaman, Ahmet; Elvan, Arif

    2016-04-01

    Echocardiographic assessment of left ventricular (LV) dyssynchrony is used to predict response to cardiac resynchronization therapy (CRT). However, the association between reduction in the extent of speckle tracking based LV-dyssynchrony and echocardiographic response to CRT has not been explored yet. The aim of this study was to assess the changes in the extent of LV dyssynchrony as a result of CRT and its association with echocardiographic response to CRT in a large consecutive series of patients. We studied 138 patients with standard CRT indication. Time-based speckle tracking longitudinal strain (maximal delay between 6-segments in 4-chamber view) was performed to assess LV-dyssynchrony at baseline and after a mean follow-up of 22 ± 8 months. Echocardiographic CRT response was defined as a reduction in LV end-systolic volume ≥15 %. Mean age was 68 ± 8 years (30 % female). Mean LV ejection fraction (LVEF) was 26 ± 7 %. Ninety six patients (70 %) were classified as echocardiographic responders. In the total study group, LV-dyssynchrony decreased from 196 ± 89 ms at baseline to 180 ± 105 ms during follow-up, P = 0.01. Of note, in responders there was a pronounced reduction in LV dyssynchrony (198 ± 88 ms at baseline vs 154 ± 50 ms after CRT, P < 0.001), whereas in non-responders there was a significant increase (191 ± 92 ms at baseline vs 243 ± 160 ms after CRT, P = 0.04). After multivariate analysis, decreased in LV-dyssynchrony, wider QRS duration and non-ischemic etiology were independently and significantly associated with CRT response. Changes in the extent of LV dyssynchrony as measured by speckle tracking after CRT are independently associated with response to CRT.

  5. 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

    2015-11-03

    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.

  6. 3-D diffusion tensor axonal tracking shows distinct SMA and pre-SMA projections to the human striatum.

    PubMed

    Lehéricy, Stéphane; Ducros, Mathieu; Krainik, Alexandre; Francois, Chantal; Van de Moortele, Pierre-François; Ugurbil, Kamil; Kim, Dae-Shik

    2004-12-01

    Studies in non-human primates have shown that medial premotor projections to the striatum are characterized as a set of distinct circuits conveying different type of information. This study assesses the anatomical projections from the supplementary motor area (SMA), pre-SMA and motor cortex (MC) to the human striatum using diffusion tensor imaging (DTI) axonal tracking. Eight right-handed volunteers were studied at 1.5 T using DTI axonal tracking. A connectivity matrix was computed, which tested for connections between cortical areas (MC, SMA and pre-SMA) and subcortical areas (posterior, middle and anterior putamen and the head of the caudate nucleus) in each hemisphere. Pre-SMA projections to the striatum were located rostral to SMA projections to the striatum. The SMA and the MC were similarly connected to the posterior and middle putamen and not to the anterior striatum. These data show that the MC and SMA have connections with similar parts of the sensorimotor compartment of the human striatum, whereas the pre-SMA sends connections to more rostral parts of the striatum, including the associative compartment.

  7. 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

  8. Assessment of training-dependent changes in the left ventricle torsion dynamics of professional soccer players using speckle-tracking echocardiography.

    PubMed

    Zócalo, Yanina; Bia, Daniel; Armentano, Ricardo L; Arias, Laura; López, Claudio; Etchart, Carolina; Guevara, Eduardo

    2007-01-01

    Recently, it has been proposed the use of speckle-tracking echography (STE) to study the left ventricle (LV) torsion dynamics, which would make LV torsion assessment more available in clinical and research cardiology. LV torsion has been described during exercise and in some sportsmen, but so far, its dynamics has not been studied in soccer players. The aims were to characterize and to compare LV apical and basal rotation, and to analyze LV torsion in professional soccer players using STE, and to determine the main differences in torsion between soccer players and age-matched non-trained individuals. The STE allowed characterizing LV rotation and torsion in both groups. LV torsion level and velocities were lesser in soccer players than in non-trained individuals. Changes in torsion in soccer players could represent physiological adaptations to training.

  9. The Value of Elastic Modulus Index as a Novel Surrogate Marker for Cardiovascular Risk Stratification by Dimensional Speckle-Tracking Carotid Ultrasonography

    PubMed Central

    Yoon, Ji Hyun; Cho, In-Jeong; Sung, Ji Min; Lee, Jinyong; Ryoo, Hojin; Shim, Chi Young; Hong, Geu-Ru; Chung, Namsik

    2016-01-01

    Background Carotid intima media thickness (CIMT) and the presence of carotid plaque have been used for risk stratification of cardiovascular disease (CVD). To date, however, the association between multi-directional functional properties of carotid artery and CVD has not been fully elucidated. We sought to explore the multi-directional mechanics of the carotid artery in relation to cardiovascular risk. Methods Four hundred one patients who underwent carotid ultrasound were enrolled between January 2010 and April 2013. A high risk of CVD was defined as more than 20% of 10-year risk based on the Framingham risk score. Using a speckle-tracking technique, the longitudinal and radial movements were analyzed in the B-mode images. Peak longitudinal and radial displacements, strain and strain rate were also measured. Beta stiffness and elastic modulus index were calculated from the radial measurements. Results Of the overall sample, 13% (52) of patients comprised the high-risk group. In multivariate logistic regression, CIMT and elastic modulus index were independently associated with a high-risk of CVD {odds ratio (OR): 1.810 [95% confidence interval (CI) 1.249–2.622] and OR: 1.767 (95% CI: 1.177–2.652); p = 0.002, 0.006, respectively}. The combination of CIMT and elastic modulus index correlated with a high-risk of CVD more so than CIMT alone. Conclusion The elastic modulus index of the carotid artery might serve as a novel surrogate marker of high-risk CVD. Measurement of the multi-directional mechanics of the carotid artery using the speckle tracking technique has potential for providing further information over conventional B-mode ultrasound for stratification of CVD risk. PMID:27721952

  10. Evaluation of right and left ventricular function using speckle tracking echocardiography in patients with arrhythmogenic right ventricular cardiomyopathy and their first degree relatives

    PubMed Central

    2012-01-01

    Introduction and aim The identification of right ventricular abnormalities in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) in early stages is still difficult. The aim of this study was to investigate if longitudinal strain based on speckle tracking can detect subtle right (RV) or left ventricular (LV) dysfunction as an early sign of ARVC. Methods and results Seventeen male patients, fulfilling Task force criteria for ARVC, 49 (32–70) years old, nineteen male first degree relatives 29 (19–73) y.o. and twenty-two healthy male volunteers 36 (24–66) y.o participated in the study. Twelve-lead and signal-averaged electrocardiograms were recorded. All subjects underwent echocardiography. LV and RV diameters, peak systolic velocity from tissue Doppler and longitudinal strain based on speckle tracking were measured from the basal and mid segments in both ventricles. RV longitudinal strain measurement was successful in first degree relatives and controls (95 resp. 86%) but less feasible in patients (59%). Results were not systematically different between first degree relatives and controls. Using discriminant analysis, we then developed an index based on echocardiographic parameters. All normal controls had an index < l while patients with abnormal ventricles had an index between 1–4. Some of the first degree relatives deviated from the normal pattern. Conclusion Longitudinal strain of LV and RV segments was significantly lower in patients than in relatives and controls. An index was developed incorporating dimensional and functional echocardiographic parameters. In combination with genetic testing this index might help to detect early phenotype expression in mutation carriers. PMID:22992412

  11. 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.

  12. FFT integration of instantaneous 3D pressure gradient fields measured by Lagrangian particle tracking in turbulent flows

    NASA Astrophysics Data System (ADS)

    Huhn, F.; Schanz, D.; Gesemann, S.; Schröder, A.

    2016-09-01

    Pressure gradient fields in unsteady flows can be estimated through flow measurements of the material acceleration in the fluid and the assumption of the governing momentum equation. In order to derive pressure from its gradient, almost exclusively two numerical methods have been used to spatially integrate the pressure gradient until now: first, direct path integration in the spatial domain, and second, the solution of the Poisson equation for pressure. Instead, we propose an alternative third method that integrates the pressure gradient field in Fourier space. Using a FFT function, the method is fast and easy to implement in programming languages for scientific computing. We demonstrate the accuracy of the integration scheme on a synthetic pressure field and apply it to an experimental example based on time-resolved material acceleration data from high-resolution Lagrangian particle tracking with the Shake-The-Box method.

  13. A comprehensive method for magnetic sensor calibration: a precise system for 3-D tracking of the tongue movements.

    PubMed

    Farajidavar, Aydin; Block, Jacob M; Ghovanloo, Maysam

    2012-01-01

    Magnetic localization has been used in a variety of applications, including the medical field. Small magnetic tracers are often modeled as dipoles and localization has been achieved by solving well-defined dipole equations. However, in practice, the precise calculation of the tracer location not only depends on solving the highly nonlinear dipole equations through numerical algorithms but also on the precision of the magnetic sensor, accuracy of the tracer magnetization, and the earth magnetic field (EMF) measurements. We have developed and implemented a comprehensive calibration method that addresses all of the aforementioned factors. We evaluated this method in a bench-top setting by moving the tracer along controlled trajectories. We also conducted several experiments to track the tongue movement in a human subject.

  14. Nuclear Speckles

    PubMed Central

    Spector, David L.; Lamond, Angus I.

    2011-01-01

    Nuclear speckles, also known as interchromatin granule clusters, are nuclear domains enriched in pre-mRNA splicing factors, located in the interchromatin regions of the nucleoplasm of mammalian cells. When observed by immunofluorescence microscopy, they usually appear as 20–50 irregularly shaped structures that vary in size. Speckles are dynamic structures, and their constituents can exchange continuously with the nucleoplasm and other nuclear locations, including active transcription sites. Studies on the composition, structure, and dynamics of speckles have provided an important paradigm for understanding the functional organization of the nucleus and the dynamics of the gene expression machinery. PMID:20926517

  15. Spatiotemporal laser speckle contrast analysis for blood flow imaging with maximized speckle contrast.

    PubMed

    Qiu, Jianjun; Li, Pengcheng; Luo, Weihua; Wang, Jia; Zhang, Hongyan; Luo, Qingming

    2010-01-01

    Laser speckle contrast imaging is a technique used for imaging blood flow without scanning. Though several studies have attempted to combine spatial and temporal statistics of laser speckle images for reducing image noise as well as preserving acceptable spatiotemporal resolution, the statistical accuracy of these spatiotemporal methods has not been thoroughly compared. Through numerical simulation and animal experiments, this study investigates the changes in the mean speckle contrast values and the relative noise of the speckle contrast images computed by these methods with various numbers of frames and spatial windows. The simulation results show that the maximum relative error of the mean speckle contrast computed by the spatiotemporal laser speckle contrast analysis (STLASCA) method, in which the speckle contrast images are computed by analyzing the 3-D spatiotemporal speckle image cube, is approximately 5%, while it is higher than 13% for other methods. Changes in the mean speckle contrast values and the relative noise computed by these methods for animal experiment data are consistent with the simulation results. Our results demonstrate that STLASCA achieves more accurate speckle contrast, and suggest that STLASCA most effectively utilizes the number of pixels, thus achieving maximized speckle contrast, and thereby maximizing the variation of the laser speckle contrast image.

  16. Spatiotemporal laser speckle contrast analysis for blood flow imaging with maximized speckle contrast

    NASA Astrophysics Data System (ADS)

    Qiu, Jianjun; Li, Pengcheng; Luo, Weihua; Wang, Jia; Zhang, Hongyan; Luo, Qingming

    2010-01-01

    Laser speckle contrast imaging is a technique used for imaging blood flow without scanning. Though several studies have attempted to combine spatial and temporal statistics of laser speckle images for reducing image noise as well as preserving acceptable spatiotemporal resolution, the statistical accuracy of these spatiotemporal methods has not been thoroughly compared. Through numerical simulation and animal experiments, this study investigates the changes in the mean speckle contrast values and the relative noise of the speckle contrast images computed by these methods with various numbers of frames and spatial windows. The simulation results show that the maximum relative error of the mean speckle contrast computed by the spatiotemporal laser speckle contrast analysis (STLASCA) method, in which the speckle contrast images are computed by analyzing the 3-D spatiotemporal speckle image cube, is approximately 5%, while it is higher than 13% for other methods. Changes in the mean speckle contrast values and the relative noise computed by these methods for animal experiment data are consistent with the simulation results. Our results demonstrate that STLASCA achieves more accurate speckle contrast, and suggest that STLASCA most effectively utilizes the number of pixels, thus achieving maximized speckle contrast, and thereby maximizing the variation of the laser speckle contrast image.

  17. 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.

  18. Combining 3D tracking and surgical instrumentation to determine the stiffness of spinal motion segments: a validation study.

    PubMed

    Reutlinger, C; Gédet, P; Büchler, P; Kowal, J; Rudolph, T; Burger, J; Scheffler, K; Hasler, C

    2011-04-01

    The spine is a complex structure that provides motion in three directions: flexion and extension, lateral bending and axial rotation. So far, the investigation of the mechanical and kinematic behavior of the basic unit of the spine, a motion segment, is predominantly a domain of in vitro experiments on spinal loading simulators. Most existing approaches to measure spinal stiffness intraoperatively in an in vivo environment use a distractor. However, these concepts usually assume a planar loading and motion. The objective of our study was to develop and validate an apparatus, that allows to perform intraoperative in vivo measurements to determine both the applied force and the resulting motion in three dimensional space. The proposed setup combines force measurement with an instrumented distractor and motion tracking with an optoelectronic system. As the orientation of the applied force and the three dimensional motion is known, not only force-displacement, but also moment-angle relations could be determined. The validation was performed using three cadaveric lumbar ovine spines. The lateral bending stiffness of two motion segments per specimen was determined with the proposed concept and compared with the stiffness acquired on a spinal loading simulator which was considered to be gold standard. The mean values of the stiffness computed with the proposed concept were within a range of ±15% compared to data obtained with the spinal loading simulator under applied loads of less than 5 Nm.

  19. A 3D front-tracking approach for simulation of a two-phase fluid with insoluble surfactant

    NASA Astrophysics Data System (ADS)

    de Jesus, Wellington C.; Roma, Alexandre M.; Pivello, Márcio R.; Villar, Millena M.; da Silveira-Neto, Aristeu

    2015-01-01

    Surface active agents play a significant role in interfacial dynamics of multiphase systems.While the understanding of their behavior is crucial to many important practical applications, realistic mathematical modeling and computer simulation represent an extraordinary task. By employing a front-tracking method with Eulerian adaptive mesh refinement capabilities in concert with a finite volume scheme for solving an advection-diffusion equation constrained to a moving and deforming interface, the numerical challenges posed by the full three-dimensional computer simulation of transient, incompressible two-phase flows with an insoluble surfactant are efficiently and accurately tackled in the present work. The individual numerical components forming the resulting methodology are here combined and applied for the first time. Verification tests to check the accuracy and the simulation of the deformation of a droplet in simple shear flow in the presence of an insoluble surfactant are performed, the results being compared to laboratory experiments as well as to other numerical data. In all the cases considered, the methodology presents excellent conservation properties for the total surfactant mass (even to machine precision under certain circumstances).

  20. Tracking Down the Causes of Recent Induced and Natural Intraplate Earthquakes with 3D Seismological Analyses in Northwest Germany

    NASA Astrophysics Data System (ADS)

    Uta, P.; Brandes, C.; Boennemann, C.; Plenefisch, T.; Winsemann, J.

    2015-12-01

    Northwest Germany is a typical low strain intraplate region with a low seismic activity. Nevertheless, 58 well documented earthquakes with magnitudes of 0.5 - 4.3 affected the area in the last 40 years. Most of the epicenters were located in the vicinity of active natural gas fields and some inside. Accordingly, the earthquakes were interpreted as a consequence of hydrocarbon recovery (e.g. Dahm et al. 2007, Bischoff et al. 2013) and classified as induced events in the bulletins of the Federal Institute for Geosciences and Natural Resources (BGR). The two major ones have magnitudes of 4.3 and 4.0. They are the strongest earthquakes ever recorded in Northern Germany. Consequently, these events raise the question whether the ongoing extraction itself can cause them or if other natural tectonic processes like glacial isostatic adjustment may considerably contribute to their initiation. Recent studies of Brandes et al. (2012) imply that lithospheric stress changes due to post glacial isostatic adjustment might be also a potential natural cause for earthquakes in Central Europe. In order to better analyse the earthquakes and to test this latter hypothesis we performed a relocalization of the events with the NonLinLoc (Lomax et al. 2000) program package and two differently scaled 3D P-wave velocity models. Depending on the station coverage for a distinct event, either a fine gridded local model (88 x 73 x 15 km, WEG-model, made available by the industry) or a coarse regional model (1600 x 1600 x 45 km, data from CRUST1.0, Laske et al. 2013) and for some cases a combination of both models was used for the relocalization. The results confirm the trend of the older routine analysis: The majority of the events are located at the margins of the natural gas fields, some of them are now located closer to them. Focal depths mostly vary between 3.5 km and 10 km. However, for some of the events, especially for the older events with relatively bad station coverage, the error bars

  1. Echoes in x-ray speckles track nanometer-scale plastic events in colloidal gels under shear

    SciTech Connect

    Rogers, Michael C.; Chen, Kui; Andrzejewski, Lukasz; Narayanan, Suresh; Ramakrishnan, Subramanian; Leheny, Robert L.; Harden, James L.

    2014-12-22

    We report x-ray photon correlation spectroscopy experiments on a concentrated nanocolloidal gel subject to in situ oscillatory shear strain. The strain causes periodic echoes in the speckle pattern that lead to peaks in the intensity autocorrelation function. Above a threshold strain that is near the first yield point of the gel, the peak amplitude decays exponentially with the number of shear cycles, signaling irreversible particle rearrangements. The wave-vector dependence of the decay rate reveals a power-law distribution in the size of regions undergoing shear-induced rearrangement. The gel also displays strain softening well below the threshold, indicating a range of strains at which the rheology is nonlinear but the microscopic deformations are reversible.

  2. Echoes in x-ray speckles track nanometer-scale plastic events in colloidal gels under shear

    NASA Astrophysics Data System (ADS)

    Rogers, Michael C.; Chen, Kui; Andrzejewski, Lukasz; Narayanan, Suresh; Ramakrishnan, Subramanian; Leheny, Robert L.; Harden, James L.

    2014-12-01

    We report x-ray photon correlation spectroscopy experiments on a concentrated nanocolloidal gel subject to in situ oscillatory shear strain. The strain causes periodic echoes in the speckle pattern that lead to peaks in the intensity autocorrelation function. Above a threshold strain that is near the first yield point of the gel, the peak amplitude decays exponentially with the number of shear cycles, signaling irreversible particle rearrangements. The wave-vector dependence of the decay rate reveals a power-law distribution in the size of regions undergoing shear-induced rearrangement. The gel also displays strain softening well below the threshold, indicating a range of strains at which the rheology is nonlinear but the microscopic deformations are reversible.

  3. Assessment of myocardial function in elite athlete’s heart at rest - 2D speckle tracking echocardiography in Korean elite soccer players

    PubMed Central

    Eun, Lucy Youngmin; Chae, Hyun Wook

    2016-01-01

    The purpose of this study was to investigate Korean elite soccer players’ myocardial function using the conventional and advanced speckle tracking imaging to compare the difference with the normal controls. We used 2D echocardiography speckle tracking echocardiography (STE) to evaluate LV regional strain in 29 elite soccer players compared to 29 age-matched healthy controls. Conventional, tissue Doppler, and STI echocardiography was performed, for strain at base and apex, rotation and torsion. There is no difference in longitudinal strain (−17.6 ± 1.8 vs −17.3 ± 2.9, p = ns), and basal radial strain. However, the significant increases were noticed in basal circumferential strain (−17.5 ± 2.6 vs −15.5 ± 8.9, p = 0.05), apical radial strain (33.1 ± 20.5 vs 22.5 ± 19.4, p = 0.02), and apical circumferential strain in soccer players (−21.4 ± 4.8 vs −16.8 ± 7.6, p = 0.005). Soccer players showed the higher rotation at base (−3.9 ± 1.9 vs −2.6 ± 3.2, p = 0.03), and apex (6.98 ± 2.62 vs 6.21 ± 3.81, p = 0.05), higher torsion (10.9 ± 3.7 vs 8.8 ± 6.3, p = 0.05). In conclusion, the elite soccer players’ heart demonstrated the unique ventricular adaptation. These alterations could benefit the cardiovascular adjustment to exercise without much loss of myocardial energy expenditure. PMID:28004817

  4. SU-E-J-135: An Investigation of Ultrasound Imaging for 3D Intra-Fraction Prostate Motion Estimation

    SciTech Connect

    O'Shea, T; Harris, E; Bamber, J; Evans, P

    2014-06-01

    Purpose: This study investigates the use of a mechanically swept 3D ultrasound (US) probe to estimate intra-fraction motion of the prostate during radiation therapy using an US phantom and simulated transperineal imaging. Methods: A 3D motion platform was used to translate an US speckle phantom while simulating transperineal US imaging. Motion patterns for five representative types of prostate motion, generated from patient data previously acquired with a Calypso system, were using to move the phantom in 3D. The phantom was also implanted with fiducial markers and subsequently tracked using the CyberKnife kV x-ray system for comparison. A normalised cross correlation block matching algorithm was used to track speckle patterns in 3D and 2D US data. Motion estimation results were compared with known phantom translations. Results: Transperineal 3D US could track superior-inferior (axial) and anterior-posterior (lateral) motion to better than 0.8 mm root-mean-square error (RMSE) at a volume rate of 1.7 Hz (comparable with kV x-ray tracking RMSE). Motion estimation accuracy was poorest along the US probe's swept axis (right-left; RL; RMSE < 4.2 mm) but simple regularisation methods could be used to improve RMSE (< 2 mm). 2D US was found to be feasible for slowly varying motion (RMSE < 0.5 mm). 3D US could also allow accurate radiation beam gating with displacement thresholds of 2 mm and 5 mm exhibiting a RMSE of less than 0.5 mm. Conclusion: 2D and 3D US speckle tracking is feasible for prostate motion estimation during radiation delivery. Since RL prostate motion is small in magnitude and frequency, 2D or a hybrid (2D/3D) US imaging approach which also accounts for potential prostate rotations could be used. Regularisation methods could be used to ensure the accuracy of tracking data, making US a feasible approach for gating or tracking in standard or hypo-fractionated prostate treatments.

  5. Echoes in x-ray speckles track nanometer-scale plastic events in colloidal gels under shear

    NASA Astrophysics Data System (ADS)

    Leheny, Robert; Rogers, Michael; Chen, Kui; Andrzejewski, Lukasz; Narayanan, Suresh; Ramakrishnan, Subramanian; Harden, James

    2015-03-01

    Any solid under applied stress possesses an elastic limit above which it yields. The microscopic signatures of yield are irreversible changes to the material's structure. We describe x-ray photon correlation spectroscopy experiments on a concentrated nanocolloidal gel subject to in situ oscillatory shear strain that provide information about the spatial character of rearrangements above yielding at the nanometer scale. The oscillatory strain causes periodic echoes in the x-ray speckle pattern, creating peaks in the intensity autocorrelation function. The peak amplitudes are attenuated above a threshold strain, signaling the onset of irreversible particle rearrangements. The gel displays strain softening well below the threshold, indicating a range of strains at which deformations are nonlinear but reversible. Above the threshold strain, the peak amplitudes decay exponentially with the number of shear cycles, demonstrating that all regions in the sample are equally susceptible to yielding and that the probability of a region yielding is independent of previous shear history. The wave-vector dependence of the decay rate reveals a power-law distribution in the size of rearranging regions, suggesting a nonequilibrium critical transition at yielding.

  6. 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

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

    PubMed

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

    2008-12-21

    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 approximately 0.5 mm for the normal adult breathing pattern to approximately 1.5 mm for more extreme cases with a low imaging frame rate of 3.4 Hz. In general

  8. 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.

  9. An Automated Pipeline for Dendrite Spine Detection and Tracking of 3D Optical Microscopy Neuron Images of In Vivo Mouse Models

    PubMed Central

    Fan, Jing; Zhou, Xiaobo; Dy, Jennifer G.; Zhang, Yong; Wong, Stephen T. C.

    2009-01-01

    The variations in dendritic branch morphology and spine density provide insightful information about the brain function and possible treatment to neurodegenerative disease, for example investigating structural plasticity during the course of Alzheimer's disease. Most automated image processing methods aiming at analyzing these problems are developed for in vitro data. However, in vivo neuron images provide real time information and direct observation of the dynamics of a disease process in a live animal model. This paper presents an automated approach for detecting spines and tracking spine evolution over time with in vivo image data in an animal model of Alzheimer's disease. We propose an automated pipeline starting with curvilinear structure detection to determine the medial axis of the dendritic backbone and spines connected to the backbone. We, then, propose the adaptive local binary fitting (aLBF) energy level set model to accurately locate the boundary of dendritic structures using the central line of curvilinear structure as initialization. To track the growth or loss of spines, we present a maximum likelihood based technique to find the graph homomorphism between two image graph structures at different time points. We employ dynamic programming to search for the optimum solution. The pipeline enables us to extract dynamically changing information from real time in vivo data. We validate our proposed approach by comparing with manual results generated by neurologists. In addition, we discuss the performance of 3D based segmentation and conclude that our method is more accurate in identifying weak spines. Experiments show that our approach can quickly and accurately detect and quantify spines of in vivo neuron images and is able to identify spine elimination and formation. PMID:19434521

  10. Evaluation of myocardial viability in old myocardial infarcted patients with CHF: delayed enhancement MRI vs. low-dose dobutamine stress speckle tracking echocardiography

    PubMed Central

    Wang, Chaofan; Han, Shuguang; Xu, Tongda; Wang, Fengli; Wang, Xiaoping; Chen, Jing; Hu, Chunfeng; Li, Dongye

    2016-01-01

    The aim of this study was to explore the significance of delayed enhancement magnetic resonance imaging (DE-MRI) combined with two-dimensional speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) to assess viable myocardium (VM) in the patients with old myocardial infarction (OMI) associated with congestive heart failure (CHF). Thirty five hospitalized OMI patients with regional wall motion abnormalities and left ventricular ejection fraction (LVEF) < 50% were recruited based on routine echocardiography. The results showed that DE-MRI facilitated the detection of VM, with a sensitivity, specificity and accuracy of 92.41%, 89.19% and 91.32%, respectively. In a parallel test of the two main parameters in STE, the sensitivity, specificity, and accuracy were improved from baseline to LDDSE (71.72% vs. 91.72%, 70.27% vs. 85.14%, and 71.23% vs. 89.50%, P < 0.05). A parallel test involving STE with LDDSE showed high sensitivity for VM. However its specificity and accuracy were lower than DE-MRI, even when combined with LDDSE. Therefore, combining these two methods, improves the sensitivity, specificity and accuracy for assessment of VM. The combination approach is the best option for the evaluation of VM using serial test. It provides further treatment options and prognosis of patients with OMI. LVEF is improved significantly after PCI in OMI patients with VM and CHF. PMID:27725854

  11. Predictors of Exercise-Induced Pulmonary Hypertension in Patients with Asymptomatic Degenerative Mitral Regurgitation: Mechanistic Insights from 2D Speckle-Tracking Echocardiography

    PubMed Central

    Kamijima, Ryo; Suzuki, Kengo; Izumo, Masaki; Kuwata, Shingo; Mizukoshi, Kei; Takai, Manabu; Kou, Seisyou; Hayashi, Akio; Kida, Keisuke; Harada, Tomoo; Akashi, Yoshihiro J.

    2017-01-01

    Presence of exercise-induced pulmonary hypertension (EIPH) in asymptomatic degenerative mitral regurgitation (DMR) determines prognosis. This study aimed to elucidate the mechanism and predictors of EIPH in asymptomatic DMR. Ninety-one consecutive asymptomatic patients with DMR who underwent exercise stress echocardiography were prospectively included. We obtained various conventional echocardiographic parameters at rest and during peak exercise, as well as left atrial (LA) function at rest using 2-dimensional speckle-tracking analysis. The 25 patients (33.3%) with EIPH were significantly older and had a greater ratio of mitral peak velocity of early filling to early diastolic mitral annular velocity during peak exercise than those without EIPH. LA strain (LAS)-s and LAS-e, indices of LA reservoir and conduit function, respectively, were significantly lower in those with EIPH than in those without EIPH. Multivariate analysis indicated that LAS-s was the only resting echocardiographic parameter that independently predicted EIPH, with a cut-off value of 26.9%. Furthermore, Kaplan-Meier curve analysis showed that symptom-free survival was markedly lower among those with reduced LAS-s. In conclusion, decreased LA reservoir function contributes to EIPH, and LAS-s at rest is a useful indicator for predicting EIPH in asymptomatic patients with DMR. PMID:28071674

  12. Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study.

    PubMed

    Hensel, Kai O; Grimmer, Franziska; Roskopf, Markus; Jenke, Andreas C; Wirth, Stefan; Heusch, Andreas

    2016-01-01

    Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV) myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM). 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5 ± 3.1 years and mean disease duration 4.3 ± 3.5 years) and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate) during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p = 0.019) and circumferential (p = 0.016) strain rate both at rest and during exercise (p = 0.021). This was more pronounced in T1DM patients with a longer disease duration (p = 0.038). T1DM patients with serum HbA1c > 9% showed impaired longitudinal (p = 0.008) and circumferential strain (p = 0.005) and a reduced E/A-ratio (p = 0.018). In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment.

  13. Subclinical Alterations of Cardiac Mechanics Present Early in the Course of Pediatric Type 1 Diabetes Mellitus: A Prospective Blinded Speckle Tracking Stress Echocardiography Study

    PubMed Central

    Hensel, Kai O.; Grimmer, Franziska; Roskopf, Markus; Jenke, Andreas C.; Wirth, Stefan; Heusch, Andreas

    2016-01-01

    Diabetic cardiomyopathy substantially accounts for mortality in diabetes mellitus. The pathophysiological mechanism underlying diabetes-associated nonischemic heart failure is poorly understood and clinical data on myocardial mechanics in early stages of diabetes are lacking. In this study we utilize speckle tracking echocardiography combined with physical stress testing in order to evaluate whether left ventricular (LV) myocardial performance is altered early in the course of uncomplicated type 1 diabetes mellitus (T1DM). 40 consecutive asymptomatic normotensive children and adolescents with T1DM (mean age 11.5 ± 3.1 years and mean disease duration 4.3 ± 3.5 years) and 44 age- and gender-matched healthy controls were assessed using conventional and quantitative echocardiography (strain and strain rate) during bicycle ergometer stress testing. Strikingly, T1DM patients had increased LV longitudinal (p = 0.019) and circumferential (p = 0.016) strain rate both at rest and during exercise (p = 0.021). This was more pronounced in T1DM patients with a longer disease duration (p = 0.038). T1DM patients with serum HbA1c > 9% showed impaired longitudinal (p = 0.008) and circumferential strain (p = 0.005) and a reduced E/A-ratio (p = 0.018). In conclusion, asymptomatic T1DM patients have signs of hyperdynamic LV contractility early in the course of the disease. Moreover, poor glycemic control is associated with early subclinical LV systolic and diastolic impairment. PMID:26839891

  14. Echocardiographic Predictors for Left Ventricular Remodeling after Acute ST Elevation Myocardial Infarction with Low Risk Group: Speckle Tracking Analysis

    PubMed Central

    Na, Hyun-Min; Lee, Joo Myung; Cha, Myung-Jin; Yoon, Yeonyee E.; Lee, Seung-Pyo; Kim, Hyung-Kwan; Kim, Yong-Jin; Sohn, Dae-Won

    2016-01-01

    Background We sought to assess echocardiographic predictors of left ventricular (LV) adverse remodeling after successfully reperfused acute ST elevation myocardial infarction (STEMI). LV remodeling is commonly found in STEMI patients and it may suggest adverse outcome in acute myocardial infarction. We sought to identify whether 2D strain and torsion be independent parameters for prediction of LV adverse remodeling. Methods We investigated 208 patients with low-risk STEMI patients who had follow up echocardiography at 6 or more months. After clinical assessments, all patients received revascularization according to current guideline. LV remodeling was defined as > 20% increase in end-diastolic volume (EDV) at follow up. Results During the follow-up (11.9 ± 5.3 months), 53 patients (25.5%) showed LV remodeling. In univariate analysis, EDV, end-systolic volume, deceleration time (DT), CK-MB, and global longitudinal strain (GLS) were associated with LV remodeling. In multivariate analysis, EDV [hazard ratio (HR): 0.922, 95% confidence interval (CI): 0.897–0.948, p< 0.001], GLS (HR: 0.842, 95% CI: 0.728–0.974, p = 0.020), DT (HR: 0.989, 95% CI: 0.980–0.998, p = 0.023) and CK-MB (HR: 1.003, 95% CI: 1.000–1.005, p = 0.033) independently predicted LV remodeling. However, global circumferential strain, net twist, and twist or untwist rate were not associated with remodeling. Conclusion Of various parameters of speckle strain, only GLS predicted adverse remodeling in STEMI patients. PMID:27358705

  15. Relation between strain dyssynchrony index determined by comprehensive assessment using speckle-tracking imaging and long-term outcome after cardiac resynchronization therapy for patients with heart failure.

    PubMed

    Tatsumi, Kazuhiro; Tanaka, Hidekazu; Matsumoto, Kensuke; Kaneko, Akihiro; Tsuji, Takayuki; Ryo, Keiko; Fukuda, Yuko; Norisada, Kazuko; Onishi, Tetsuari; Yoshida, Akihiro; Kawai, Hiroya; Hirata, Ken-Ichi

    2012-04-15

    Strain dyssynchrony index (SDI), which was a marker of dyssynchrony and residual myocardial contractility, can predict left ventricular reverse remodeling short-term after cardiac resynchronization therapy (CRT). We investigated SDI-predicted long-term outcome after CRT in patients with heart failure (HF). We studied 74 patients with HF who underwent CRT. SDI was calculated as the average difference between peak and end-systolic strain from 6 segments for radial and circumferential SDIs and 18 segments for longitudinal SDI using 2-dimensional speckle-tracking strain. Based on our previous findings, the predefined cutoff for significant dyssynchrony and residual myocardial contractility was a radial SDI ≥6.5%, a circumferential SDI ≥3.2%, and a longitudinal SDI ≥3.6%. The predefined principal outcome variable was the combined end point of death or hospitalization owing to deteriorating HF. Long-term follow-up after CRT was tracked over 4 years. The primary end point of prespecified events occurred in 14 patients (19%). An association with a favorable long-term outcome after CRT was observed in patients with significant radial, circumferential, and longitudinal SDIs (p <0.001, <0.005, and 0.010 vs patients without significant SDIs, respectively). Furthermore, cardiovascular event-free rate after CRT in patients with positivity of 3 for the 3 SDIs was 100% better than that in patients with positivity of 1 (52%, p <0.005) or 0 (31%, p <0.001) for the 3 SDIs. In conclusion, SDIs can successfully predict long-term outcome after CRT in patients with HF. Moreover, the approach combining the 3 types of SDI leads to a more accurate prediction than the use of individual parameters. These findings may have clinical implications in patients with CRT.

  16. On the local acceleration and flow trajectory of jet flows from circular and semi-circular pipes via 3D particle tracking velocimetry

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Tae; Liberzon, Alex; Chamorro, Leonardo P.

    2015-11-01

    The distinctive differences between two jet flows that share the same hydraulic diameter dh = 0.01 m and Re ~ 6000, but different (nozzle) shape are explored via 3D Particle Tracking Velocimetry using OpenPTV (http://www.openptv.net). The two jets are formed from circular and semicircular pipes and released in a quiescent water tank of 40 dh height, 40 dh wide, and 200 dh long. The recirculating system is seeded with 100 μm particles, where flow measurements are performed in the intermediate flow field (14.5 < x /dh <18.5) at 550Hz for a total of ~ 30,000 frames. Analysis is focused on the spatial distribution of the local flow acceleration and curvature of the Lagrangian trajectories. The velocity and acceleration of particles are estimated by low-pass filtering their position with a moving cubic spline fitting, while the curvature is obtained from the Frenet-Serret equations. Probability density functions (p.d.f.) of these quantities are obtained at various sub-volumes containing a given streamwise velocity range, and compared between the two cases to evaluate the memory effects in the intermediate flow field.

  17. 3D motion and strain estimation of the heart: initial clinical findings

    NASA Astrophysics Data System (ADS)

    Barbosa, Daniel; Hristova, Krassimira; Loeckx, Dirk; Rademakers, Frank; Claus, Piet; D'hooge, Jan

    2010-03-01

    The quantitative assessment of regional myocardial function remains an important goal in clinical cardiology. As such, tissue Doppler imaging and speckle tracking based methods have been introduced to estimate local myocardial strain. Recently, volumetric ultrasound has become more readily available, allowing therefore the 3D estimation of motion and myocardial deformation. Our lab has previously presented a method based on spatio-temporal elastic registration of ultrasound volumes to estimate myocardial motion and deformation in 3D, overcoming the spatial limitations of the existing methods. This method was optimized on simulated data sets in previous work and is currently tested in a clinical setting. In this manuscript, 10 healthy volunteers, 10 patient with myocardial infarction and 10 patients with arterial hypertension were included. The cardiac strain values extracted with the proposed method were compared with the ones estimated with 1D tissue Doppler imaging and 2D speckle tracking in all patient groups. Although the absolute values of the 3D strain components assessed by this new methodology were not identical to the reference methods, the relationship between the different patient groups was similar.

  18. Three-dimensional speckle-noise reduction by using coherent integral imaging.

    PubMed

    Moon, Inkyu; Javidi, Bahram

    2009-04-15

    We present a 3D imaging method to reduce speckle noise that exists in coherent imaging systems. This approach is based on integral imaging (II). The elemental images set having speckle-noise patterns of a 3D object is obtained by II technique under coherent illumination. The computational geometrical ray-propagation algorithm is applied to the elemental images in order to reconstruct the original 3D object. A uniform probability-density function is assumed for modeling the phase distribution of the speckle patterns. The statistical point estimator is used for 3D speckle removal. Speckle index is calculated to compare the computational reconstruction using the proposed method with that of conventional coherent image degraded by speckle patterns for 3D object reconstruction and by object recognition. Experimental results are presented. The speckle index, mean square error, and signal-to-noise ratio are used as performance metrics and are shown to have been significantly improved by the proposed method to reduce speckle noise in the 3D object reconstruction. 3D reconstruction experiments of objects with reduced speckle noise are presented. To the best of our knowledge, this is the first report on 3D speckle removal using II and statistical estimation algorithms.

  19. Reference Ranges of Left Ventricular Strain Measures by Two-Dimensional Speckle Tracking Echocardiography in Children: A Systematic Review and Meta-Analysis

    PubMed Central

    Levy, Philip T.; Machefsky, Aliza; Sanchez, Aura A.; Patel, Meghna D.; Rogal, Sarah; Fowler, Susan; Yaeger, Lauren; Hardi, Angela; Holland, Mark R.; Hamvas, Aaron; Singh, Gautam K.

    2015-01-01

    Background The establishment of the range of reference values and associated variations of two-dimensional speckle-tracking echocardiography (2DSTE) derived left ventricular (LV) strain is a prerequisite for its routine clinical adoption in pediatrics. The aims were to perform a meta-analysis of normal ranges of LV global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS) measurements derived by 2DSTE in children and identify confounding factors that may contribute to variances in reported measures. Methods A systematic review was launched in Medline, Embase, Scopus, CINAHL, and Cochrane. Search hedges were created to cover the concepts of pediatrics, speckle-tracking echocardiography, and left heart ventricle. Two investigators independently identified and included studies if they reported the 2DSTE derived LV GLS, GCS or GRS. The weighted mean was estimated by using random-effects with 95% confidence interval (CI), heterogeneity was assessed by the Cochran's Q statistic and the inconsistency index (I2) and publication was evaluated using the Egger test. Effects of demographic (age), clinical, and vendor variables were assessed in a meta-regression. Results The search identified 2325 children from 43 data sets. The reported normal mean values of GLS among the studies varied from -16.7% to -23.6% (mean -20.2%, 95% CI -19.5% to -20.8%), GCS varied from -12.9% to -31.4% (mean -22.3%, 95% CI -19.9% to -24.6%) and GRS, varied from 33.9% to 54.5 % (mean 45.2 95% CI 38.3 to 51.7). 26 studies reported LS only from the apical 4-chamber view with a mean of -20.4%, (95% CI -19.8% to -21.7%). 23 studies reported CS (mean, -20.3%, 95% CI -19.4% to -21.2%) and RS (mean, 46.7%, 95% CI 42.3% to 51.1%) from the short axis view at the mid-ventricular level. A significant apex-to-base segmental longitudinal strain (SLS) gradient (P < .01) was observed in the LV free wall. There was significant between- study heterogeneity and inconsistency (I2 > 94% and P < .001

  20. SRBF: Speckle reducing bilateral filtering.

    PubMed

    Balocco, Simone; Gatta, Carlo; Pujol, Oriol; Mauri, Josepa; Radeva, Petia

    2010-08-01

    Speckle noise negatively affects medical ultrasound image shape interpretation and boundary detection. Speckle removal filters are widely used to selectively remove speckle noise without destroying important image features to enhance object boundaries. In this article, a fully automatic bilateral filter tailored to ultrasound images is proposed. The edge preservation property is obtained by embedding noise statistics in the filter framework. Consequently, the filter is able to tackle the multiplicative behavior modulating the smoothing strength with respect to local statistics. The in silico experiments clearly showed that the speckle reducing bilateral filter (SRBF) has superior performances to most of the state of the art filtering methods. The filter is tested on 50 in vivo US images and its influence on a segmentation task is quantified. The results using SRBF filtered data sets show a superior performance to using oriented anisotropic diffusion filtered images. This improvement is due to the adaptive support of SRBF and the embedded noise statistics, yielding a more homogeneous smoothing. SRBF results in a fully automatic, fast and flexible algorithm potentially suitable in wide ranges of speckle noise sizes, for different medical applications (IVUS, B-mode, 3-D matrix array US).

  1. Streak speckle velocimetry

    NASA Astrophysics Data System (ADS)

    Re Calegari, Gabriele; Ferri, Fabio

    2014-01-01

    We present a method for fluid velocimetry based on a single-exposure analysis of the streak speckle pattern generated by sub-micron tracking particles illuminated with coherent light. It works in real-time and provides two dimensional velocity mappings in the direction orthogonal to the optical axis, independently of particle concentration and size. It is immune of any spurious light acting as undesired heterodyne signal and can probe velocities much higher (˜three orders of magnitude) than methods based on double-exposure analysis. The method has been tested by using rigid diffusers of different heterodyne strength and applied to map the flow of a confined fluid.

  2. Heterodyne speckle velocimetry

    SciTech Connect

    Alaimo, M. D.; Magatti, D.; Ferri, F.; Potenza, M.A.C.

    2006-05-08

    We present a simple method for fluid velocimetry based on the velocity of the heterodyne speckles generated by tracking particles illuminated with coherent light. It works in real time and provides instantaneous two-dimensional velocity mappings in the direction orthogonal to the optical axis, independently of the particle concentration and size, also for subwavelength particles. It also provides the velocity distribution of the fluid over the entire sample thickness. The method has been quantitatively tested by using the motions of rigid diffusers and applied for mapping the flow of a confined fluid.

  3. 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

  4. 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

  5. A PDE-based Regularization Algorithm toward Reducing Speckle Tracking Noise: A Feasibility Study for Ultrasound Breast Elastography

    PubMed Central

    Guo, Li; Xu, Yan; Xu, Zhengfu; Jiang, Jingfeng

    2015-01-01

    Obtaining accurate ultrasonically-estimated displacements along both axial (parallel to the acoustic beam) and lateral (perpendicular to the beam) directions is an important task for various clinical elastography applications (e.g. modulus reconstruction and temperature imaging). In this study, a partial differential equation (PDE)-based regularization algorithm was proposed to enhance motion tracking accuracy. More specifically, the proposed PDE-based algorithm, utilizing two-dimensional displacement estimates from a conventional elastography system, attempted to iteratively reduce noise contained in the original displacement estimates by mathematical regularization. In this study, the physical constraint used by the above-mentioned mathematical regularization was tissue incompressibility. This proposed algorithm was tested using computer-simulated data, a tissue-mimicking phantom and in vivo breast lesion data. Computer simulation results showed that the method significantly improved the accuracy of lateral tracking (e.g. 17X at 0.5% compression). From in vivo breast lesion data investigated, we have found that, as compared to the conventional method, higher quality axial and lateral strain images (e.g. at least 78% improvements among the estimated contrast-to-noise ratios of lateral strain images) were obtained. Our initial results demonstrated that this conceptually and computationally simple method could be useful to improve the image quality for ultrasound elastography with current clinical equipment as a post-processing tool. PMID:25452434

  6. Radial left ventricular dyssynchrony by speckle tracking in apical versus non apical right ventricular pacing- evidence of dyssynchrony on medium term follow up

    PubMed Central

    Choudhary, Dinesh; Chaurasia, Amit Kumar; Kumar, S Mahesh; Arulkumar, Ajeet; Thajudeen, Anees; Namboodiri, Narayanan; Sanjay, G; Abhilash, SP; Ajitkumar, VK; JA, Tharakan

    2016-01-01

    Introduction: To study effects of various sites of right ventricular pacing lead implantation on left ventricular function by 2-dimensional (2D) speckle tracking for radial strain and LV dyssynchrony. Methods: This was retrospective prospective study. Fifteen patients each with right ventricular (RV) apical (RV apex and apical septum) and non-apical (mid septal and low right ventricular outflow tract [RVOT]) were programmed to obtain 100% ventricular pacing for evaluation by echo. Location and orientation of lead tip was noted and archived by fluoroscopy. Electrocardiography (ECG) was archived and 2D echo radial dyssynchrony was calculated. Results: The baseline data was similar between two groups. Intraventricular dyssynchrony was significantly more in apical location as compared to non-apical location (radial dyssynchrony: 108.2 ± 50.2 vs. 50.5 ± 24, P < 0.001; septal to posterior wall delay [SLWD] 63.5 ± 27.5 vs. 34 ± 10.7, P < 0.001, SPWD 112.5 ± 58.1 vs. 62.7 ± 12.1, P = 0.003). The left ventricular ejection fraction was decreased more in apical location than non apical location. Interventricular dyssynchrony was more in apical group but was not statistically significant. The QRS duration, QTc and lead thresholds were higher in apical group but not statistically significant. Conclusion: Pacing in non apical location (RV mid septum or low RVOT) is associated with less dyssynchrony by specific measures like 2D radial strain and correlates with better ventricular function in long term. PMID:27069563

  7. Impact of surgical correction of tetralogy of fallot on short-term right and left ventricular function as determined by 2-dimensional speckle tracking echocardiography.

    PubMed

    Li, Yuman; Wang, Xinfang; Lv, Qing; Wang, Jing; Yang, YaLi; He, Lin; Yuan, Li; Zhang, Li; Xie, Mingxing

    2016-08-01

    Right ventricular (RV) and left ventricular (LV) dysfunction is an important determinant of poor clinical status in repaired patients with tetralogy of Fallot (TOF). The purpose of our study is to assess the impact of surgical repair on short-term RV and LV function by 2-dimensional speckle tracking echocardiography (STE).Sixty-seven patients (median age 12 months) with TOF before and 6 months after repair and 35 healthy subjects were studied. The patients were divided into the younger (age at surgery ≤12 months) and older (age at surgery >12 months) subgroups. RV and LV global longitudinal systolic strain and strain rate (SR), and LV global circumferential and radial systolic strain and SR were measured by STE. After repair, RV longitudinal strain and SR increased in the younger patients, whereas RV longitudinal SR was decreased in the older patients. LV deformation parameters were unchanged in all patients. In the multivariate analysis, patients with better RV and LV deformation parameters preoperatively were identified to have better RV and LV strain and SR postoperatively (P < 0.05 for all). The surgical approach of the pulmonary valve ring was predictive of RV and LV systolic function postoperatively (P < 0.05 for all).After TOF repair, short-term RV function improvement is identified in the younger but not in the older patients, whereas LV function is unchanged in all patients. The preoperative RV and LV deformational indices are the determinant of postoperative biventricular function improvement. STE appears to be a valuable tool for assessment of biventricular function after congenital heart disease surgery.

  8. Assessment of myocardial viability in patients with acute myocardial infarction by two-dimensional speckle tracking echocardiography combined with low-dose dobutamine stress echocardiography.

    PubMed

    Gong, Lei; Li, Dongye; Chen, Junhong; Wang, Xiaoping; Xu, Tongda; Li, Wenhua; Ren, Shaoyang; Wang, Cheng

    2013-06-01

    It is clinically important to determine the myocardial viability of regional wall motion abnormality segments in patients with acute myocardial infarction (AMI). The purpose of this study was to ascertain the ability and value of a combination of speckle tracking echocardiography (STE) and low dose dobutamine stress echocardiography (LDDSE) for the evaluation of viable myocardium in patients with AMI. Forty-two hospitalized patients with AMI and left ventricular systolic dysfunction (left ventricular ejection fraction <50%) were underwent STE in conjunction with LDDSE and dual isotope simultaneous acquisition single photon emission computed tomography (DISA-SPECT). Percutaneous coronary intervention (PCI) was performed subsequently in all patients. STE was used to measure radial, circumferential, and longitudinal end-systolic strain and peak systolic strain rate. The movement of each segment was observed by routine echocardiography 1, 3, and 6 months after PCI, and its improvement over time was the criterion of viable myocardium. The sensitivity, specificity and accuracy of DISA-SPECT for the assessment of viable myocardium were 83.6, 74.4, and 80.7%, respectively. Among the radial, circumferential, and longitudinal strain and strain rate parameters, only longitudinal strain (LS) and longitudinal strain rate (LSr) at rest and LDDSE emerged as independent predictors of viable myocardium, When combining LS and LSr at LDDSE, the sensitivity, specificity and accuracy for the assessment of viable myocardium rose to 89.8, 90.2 and 89.9%, respectively. The sensitivity of STE in conjunction with LDDSE was similar to DISA-SPECT for detecting viable myocardium in patients with AMI, but the specificity and accuracy of STE performed with LDDSE were higher than DISA-SPECT.

  9. Speckle tracking determination of mitral tissue annular displacement: comparison with strain and ejection fraction, and association with outcomes in haemodialysis patients.

    PubMed

    Chiu, Diana Y Y; Abidin, Nik; Hughes, John; Sinha, Smeeta; Kalra, Philip A; Green, Darren

    2016-10-01

    Abnormal Global longitudinal strain (GLS) and reduced left ventricular ejection fraction (LVEF) are established poor prognostic risk factors in haemodialysis patients. Tissue motion annular displacement of mitral valve annulus (TMAD), determined by speckle tracking echocardiography (STE), can be performed rapidly and is an indicator of systolic dysfunction, but has been less well explored. This study aims to compare TMAD with GLS and LVEF and its association with outcomes in haemodialysis patients. 198 haemodialysis patients (median age 64.2 years, 69 % men) had 2D echocardiography, with STE determined GLS and TMAD. Bland-Altman analysis and linear regression assessed relationship between GLS, LVEF and TMAD. Cox regression analysis investigated association of TMAD with mortality and cardiac events. TMAD had low inter- and intra-observer variability with small biases and narrow limits of agreement (LOA) (bias of -0.01 ± 1.32 (95 % LOA was -2.60 to 2.58) and -0.07 ± 1.27 (95 % LOA -2.55 to 2.41) respectively). There was a moderate negative correlation between GLS and LVEF (r = -0.383, p < 0.001) and a weak positive correlation between TMAD and LVEF (r = 0.248, p < 0.001). There was strong negative correlation of TMAD with GLS (r = -0.614, p < 0.001). In a multivariable Cox regression analysis, TMAD was not associated with mortality (HR 1.04, 95 % CI 0.91-1.19), cardiac death (HR 1.03, 95 % CI 0.80-1.32) or cardiac events (HR 0.91, 95 % CI 0.80-1.02). TMAD is a quick and reproducible alternative to GLS which may be very useful in cardiovascular risk assessment, but does not have the same prognostic value in HD patients as GLS.

  10. ST-segment elevation in the recovery phase of nuclear exercise stress test with ⁹⁹mTc-sestamibi in a patient with critical RCA stenosis and subtle systolic dysfunction in speckle tracking imaging.

    PubMed

    Piszczek, Stanislaw; Dziuk, Miroslaw; Mazurek, Andrzej; Krzesiński, Paweł; Jaguś-Jamiola, Agnieszka; Ryczek, Robert; Tkaczewski, Konrad; Skrobowski, Andrzej; Cwetsch, Andrzej

    2012-04-24

    An asymptomatic Caucasian male patient underwent coronary artery disease diagnostics. Standard exercise treadmill test was inconclusive, and Holter ECG study didn't show any significant abnormalities. Considering the high risk of ischemic heart disease nuclear exercise stress test was performed,which revealed ST-segment elevation in the recovery phase of the treadmill exercise test. Single photon emission computed tomography (SPECT/CT) showed myocardial perfusion abnormalities in the inferior and lateral walls of the left ventricle. Furthermore,speckle tracking imaging showed subtle left ventricle dysfunction. Finally critical stenosis in the second segment of right coronary artery was diagnosed in coronary angiography.

  11. Strain and strain rate by speckle-tracking echocardiography correlate with pressure-volume loop-derived contractility indices in a rat model of athlete's heart.

    PubMed

    Kovács, Attila; Oláh, Attila; Lux, Árpád; Mátyás, Csaba; Németh, Balázs Tamás; Kellermayer, Dalma; Ruppert, Mihály; Török, Marianna; Szabó, Lilla; Meltzer, Anna; Assabiny, Alexandra; Birtalan, Ede; Merkely, Béla; Radovits, Tamás

    2015-04-01

    Contractile function is considered to be precisely measurable only by invasive hemodynamics. We aimed to correlate strain values measured by speckle-tracking echocardiography (STE) with sensitive contractility parameters of pressure-volume (P-V) analysis in a rat model of exercise-induced left ventricular (LV) hypertrophy. LV hypertrophy was induced in rats by swim training and was compared with untrained controls. Echocardiography was performed using a 13-MHz linear transducer to obtain LV long- and short-axis recordings for STE analysis (GE EchoPAC). Global longitudinal (GLS) and circumferential strain (GCS) and longitudinal (LSr) and circumferential systolic strain rate (CSr) were measured. LV P-V analysis was performed using a pressure-conductance microcatheter, and load-independent contractility indices [slope of the end-systolic P-V relationship (ESPVR), preload recruitable stroke work (PRSW), and maximal dP/dt-end-diastolic volume relationship (dP/dtmax-EDV)] were calculated. Trained rats had increased LV mass index (trained vs. control; 2.76 ± 0.07 vs. 2.14 ± 0.05 g/kg, P < 0.001). P-V loop-derived contractility parameters were significantly improved in the trained group (ESPVR: 3.58 ± 0.22 vs. 2.51 ± 0.11 mmHg/μl; PRSW: 131 ± 4 vs. 104 ± 2 mmHg, P < 0.01). Strain and strain rate parameters were also supernormal in trained rats (GLS: -18.8 ± 0.3 vs. -15.8 ± 0.4%; LSr: -5.0 ± 0.2 vs. -4.1 ± 0.1 Hz; GCS: -18.9 ± 0.8 vs. -14.9 ± 0.6%; CSr: -4.9 ± 0.2 vs. -3.8 ± 0.2 Hz, P < 0.01). ESPVR correlated with GLS (r = -0.71) and LSr (r = -0.53) and robustly with GCS (r = -0.83) and CSr (r = -0.75, all P < 0.05). PRSW was strongly related to GLS (r = -0.64) and LSr (r = -0.71, both P < 0.01). STE can be a feasible and useful method for animal experiments. In our rat model, strain and strain rate parameters closely reflected the improvement in intrinsic contractile function induced by exercise training.

  12. Two-dimensional speckle-tracking-derived segmental peak systolic longitudinal strain identifies regional myocardial involvement in patients with myocarditis and normal global left ventricular systolic function.

    PubMed

    Uppu, Santosh C; Shah, Amee; Weigand, Justin; Nielsen, James C; Ko, H Helen; Parness, Ira A; Srivastava, Shubhika

    2015-06-01

    The presence of myocardial late gadolinium enhancement (LGE) by cardiac magnetic resonance (CMR) imaging in concert with electrocardiography and elevated biomarkers helps support the diagnosis of acute myocarditis. Two-dimensional echocardiography is limited to global and qualitative regional function assessment and may not contribute to the diagnosis, especially in the presence of normal LV systolic function. Two-dimensional speckle-tracking (2D-STE)-derived segmental peak systolic (pkS) longitudinal strain (LS) may identify segmental myocardial involvement in myocarditis. We sought to identify an association between segmental pkS, LGE, and troponin levels in patients with myocarditis. Retrospective analysis of myocardial segmental function by 2D-STE segmental strain was compared to the presence of LGE and admission peak troponin levels in patients with acute myocarditis and preserved global LV systolic function. American Heart Association 17-segment model was used for comparison between imaging modalities. Global function was assessed by m-mode-derived shortening fraction (SF). Descriptive statistics and regression analysis were utilized. Forty-four CMRs performed to evaluate for myocarditis were identified. Of the 44, 10 patients, median age 17.5 years (14-18.5 years) and median SF 35 % (28-44 %), had paired CMR and 2D-STE data for analysis, and 161/170 segments could be analyzed by both methods for comparison. PkS LS was decreased in 51 % of segments that were positive for LGE with average pkS of -14.7 %. Segmental pkS LS abnormalities were present in all but one patient who had abnormal pkS circumferential strain. Global pkS LS was decreased in patients with myocarditis. There is a moderate correlation between decreased pkS LS and the presence of LGE by CMR, 2D-STE for myocardial involvement in acute myocarditis can serve as an useful noninvasive adjunct to the existing tests used for the diagnosis of acute myocarditis and might have a role in prognostication.

  13. Global cardiac alterations detected by speckle-tracking echocardiography in Fabry disease: left ventricular, right ventricular, and left atrial dysfunction are common and linked to worse symptomatic status.

    PubMed

    Morris, Daniel A; Blaschke, Daniela; Canaan-Kühl, Sima; Krebs, Alice; Knobloch, Gesine; Walter, Thula C; Haverkamp, Wilhelm

    2015-02-01

    The aim of this study was to test the hypothesis that in patients with Fabry disease, 2D speckle-tracking echocardiography (2DSTE) could detect functional myocardial alterations such as left ventricular (LV), right ventricular (RV), and left atrial (LA) dysfunction, even when conventional cardiac measurements are normal. In addition, we hypothesized that these global cardiac alterations could be linked to worse symptomatic status in these patients. Fifty patients with Fabry disease and a control group of 118 healthy subjects of similar age and gender were included. The myocardial function and structural changes of the LV, RV, and LA were analyzed by 2DSTE and cardiac magnetic resonance imaging. Patients with Fabry disease had significantly lower functional myocardial values of the LV, RV, and LA than healthy subjects (LV, RV, and LA strain -18.1 ± 4.0, -21.4 ± 4.9, and 29.7 ± 9.9 % vs. -21.6 ± 2.2, -25.2 ± 4.0, and 44.8 ± 11.1 %, respectively, P < 0.001) and elevated rates of LV, RV, and LA myocardial dysfunction (24, 20, and 26 %, respectively), even when conventional cardiac measurements such as LVEF, TAPSE, and LAVI were normal. LV septal wall thickness ≥15 mm, RV free wall thickness ≥7 mm, and LV longitudinal dysfunction were the principal factors linked to reduced LV, RV, and LA strain, respectively. In addition, but to a lesser extent, LV and RV fibrosis were linked to reduced LV and RV strain. Patients with reduced LV, RV, and LA strain had worse functional class (dyspnea-NYHA classification) than those with normal cardiac function. In conclusion, in patients with Fabry disease, 2DSTE analyses detect LV, RV, and LA functional myocardial alterations, even when conventional cardiac measurements are normal. These functional myocardial alterations are common and significantly associated with worse symptomatic status in Fabry patients. Therefore, these findings provide important evidence to introduce global myocardial analyses using 2DSTE in the early

  14. Dual-color multiple-particle tracking at 50-nm localization and over 100-µm range in 3D with temporal focusing two-photon microscopy

    PubMed Central

    Ding, Yu; Li, Chunqiang

    2016-01-01

    Nanoscale particle tracking in three dimensions is crucial to directly observe dynamics of molecules and nanoparticles in living cells. Here we present a three-dimensional particle tracking method based on temporally focused two-photon excitation. Multiple particles are imaged at 30 frames/s in volume up to 180 × 180 × 100 µm3. The spatial localization precision can reach 50 nm. We demonstrate its capability of tracking fast swimming microbes at speed of ~200 µm/s. Two-photon dual-color tracking is achieved by simultaneously exciting two kinds of fluorescent beads at 800 nm to demonstrate its potential in molecular interaction studies. Our method provides a simple wide-field fluorescence imaging approach for deep multiple-particle tracking. PMID:27867724

  15. Optical vortex behavior in dynamic speckle fields.

    PubMed

    Kirkpatrick, Sean J; Khaksari, Kosar; Thomas, Dennis; Duncan, Donald D

    2012-05-01

    The dynamic behavior of phase singularities, or optical vortices, in the pseudo-phase representation of dynamic speckle patterns is investigated. Sequences of band-limited, dynamic speckle patterns with predetermined Gaussian decorrelation behavior were generated, and the pseudo-phase realizations of the individual speckle patterns were calculated via a two-dimensional Hilbert transform algorithm. Singular points in the pseudo-phase representation are identified by calculating the local topological charge as determined by convolution of the pseudo-phase representations with a series of 2×2 nabla filters. The spatial locations of the phase singularities are tracked over all frames of the speckle sequences, and recorded in three-dimensional space (x,y,f), where f is frame number in the sequence. The behavior of the phase singularities traces 'vortex trails' which are representative of the speckle dynamics. Slowly decorrelating speckle patterns results in long, relatively straight vortex trails, while rapidly decorrelating speckle patterns results in tortuous, relatively short vortex trails. Optical vortex analysis such as described herein can be used as a descriptor of biological activity, flow, and motion.

  16. 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.

  17. 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.

  18. Determining asteroid spin states using radar speckles

    NASA Astrophysics Data System (ADS)

    Busch, Michael W.; Kulkarni, Shrinivas R.; Brisken, Walter; Ostro, Steven J.; Benner, Lance A. M.; Giorgini, Jon D.; Nolan, Michael C.

    2010-10-01

    Knowing the shapes and spin states of near-Earth asteroids is essential to understanding their dynamical evolution because of the Yarkovsky and YORP effects. Delay-Doppler radar imaging is the most powerful ground-based technique for imaging near-Earth asteroids and can obtain spatial resolution of <10 m, but frequently produces ambiguous pole direction solutions. A radar echo from an asteroid consists of a pattern of speckles caused by the interference of reflections from different parts of the surface. It is possible to determine an asteroid's pole direction by tracking the motion of the radar speckle pattern. Speckle tracking can potentially measure the poles of at least several radar targets each year, rapidly increasing the available sample of NEA pole directions. We observed the near-Earth asteroid 2008 EV5 with the Arecibo planetary radar and the Very Long Baseline Array in December 2008. By tracking the speckles moving from the Pie Town to Los Alamos VLBA stations, we have shown that EV5 rotates retrograde. This is the first speckle detection of a near-Earth asteroid.

  19. 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

  20. 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…

  1. [Comparative evaluation of left ventricular function by two-dimensional echocardiography and three-dimensional speckle-tracking echocardiography in noncompaction cardiomyopathy. Results from the MAGYAR-Path Study].

    PubMed

    Kalapos, Anita; Domsik, Péter; Forster, Tamás; Nemes, Attila

    2013-08-25

    Bevezetés: A noncompaction cardiomyopathia a myocardium kompaktálódásának hiányában kialakuló kórkép, amely a bal kamra diszfunkciójával jár együtt. Célkitűzés: Jelen tanulmány célja a balkamra-diszfunkció összehasonlító vizsgálata volt kétdimenziós echokardiográfia és háromdimenziós speckle-tracking echokardiográfia során noncompaction cardiomyopathiában. Módszer: Jelen tanulmányban hét, noncompaction cardiomyopathiában szenvedő beteget (62,9±8,5 év, három férfi) és 10, korban és nemben egyeztetett kontrollesetet (60,7±7,7 év, két férfi) vizsgáltak kétdimenziós echokardiográfia és háromdimenziós speckle-tracking echokardiográfia során a bal kamra funkciójának vizsgálata céljából. Eredmények: Emelkedett bal kamrai végdiasztolés és végszisztolés térfogatértékek, valamint csökkent bal kamrai ejekciós frakció volt igazolható noncompaction cardiomyopathia fennállása esetén. Valamennyi háromdimenziós speckle-tracking echokardiográfia során számított strainparaméter csökkentnek bizonyult noncompaction cardiomyopathia esetén a kontrollokhoz képest. A háromdimenziós speckle-tracking echokardiográfia során mért rotációs paraméterek a bal kamra apicalis és basalis szegmentumainak egyirányú mozgását („rigid body rotation”) igazolták noncompaction cardiomyopathiában. Következtetések: A bal kamra funkciója és szegmentumainak kontraktilitása lényegesen beszűkült noncompaction cardiomyopathiában. A bal kamrai csavarodás (twist) noncompaction cardiomyopathia fennállása esetén hiányzik. Orv. Hetil., 2013, 154, 1352–1359.

  2. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITHOUT TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    Apollo's 3-dimensional graphics hardware, but does not take advantage of the shading and hidden line/surface removal capabilities of the Apollo DN10000. Although this implementation does not offer a capability for putting text on plots, it does support the use of a mouse to translate, rotate, or zoom in on views. The version 3.6b+ Apollo implementations of PLOT3D (ARC-12789) and PLOT3D/TURB3D (ARC-12785) were developed for use on Apollo computers running UNIX System V with BSD 4.3 extensions and the graphics library GMR3D Version 2.0. The standard distribution media for each of these programs is a 9-track, 6250 bpi magnetic tape in TAR format. Customers purchasing one implementation version of PLOT3D or PLOT3D/TURB3D will be given a $200 discount on each additional implementation version ordered at the same time. Version 3.6b+ of PLOT3D and PLOT3D/TURB3D are also supported for the following computers and graphics libraries: 1) generic UNIX Supercomputer and IRIS, suitable for CRAY 2/UNICOS, CONVEX, and Alliant with remote IRIS 2xxx/3xxx or IRIS 4D (ARC-12779, ARC-12784); 2) VAX computers running VMS Version 5.0 and DISSPLA Version 11.0 (ARC-12777, ARC-12781); 3) generic UNIX and DISSPLA Version 11.0 (ARC-12788, ARC-12778); and (4) Silicon Graphics IRIS 2xxx/3xxx or IRIS 4D workstations (ARC-12783, ARC-12782). Silicon Graphics Iris, IRIS 4D, and IRIS 2xxx/3xxx are trademarks of Silicon Graphics Incorporated. VAX and VMS are trademarks of Digital Electronics Corporation. DISSPLA is a trademark of Computer Associates. CRAY 2 and UNICOS are trademarks of CRAY Research, Incorporated. CONVEX is a trademark of Convex Computer Corporation. Alliant is a trademark of Alliant. Apollo and GMR3D are trademarks of Hewlett-Packard, Incorporated. UNIX is a registered trademark of AT&T.

  3. PLOT3D/AMES, APOLLO UNIX VERSION USING GMR3D (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01

    Apollo's 3-dimensional graphics hardware, but does not take advantage of the shading and hidden line/surface removal capabilities of the Apollo DN10000. Although this implementation does not offer a capability for putting text on plots, it does support the use of a mouse to translate, rotate, or zoom in on views. The version 3.6b+ Apollo implementations of PLOT3D (ARC-12789) and PLOT3D/TURB3D (ARC-12785) were developed for use on Apollo computers running UNIX System V with BSD 4.3 extensions and the graphics library GMR3D Version 2.0. The standard distribution media for each of these programs is a 9-track, 6250 bpi magnetic tape in TAR format. Customers purchasing one implementation version of PLOT3D or PLOT3D/TURB3D will be given a $200 discount on each additional implementation version ordered at the same time. Version 3.6b+ of PLOT3D and PLOT3D/TURB3D are also supported for the following computers and graphics libraries: 1) generic UNIX Supercomputer and IRIS, suitable for CRAY 2/UNICOS, CONVEX, and Alliant with remote IRIS 2xxx/3xxx or IRIS 4D (ARC-12779, ARC-12784); 2) VAX computers running VMS Version 5.0 and DISSPLA Version 11.0 (ARC-12777, ARC-12781); 3) generic UNIX and DISSPLA Version 11.0 (ARC-12788, ARC-12778); and (4) Silicon Graphics IRIS 2xxx/3xxx or IRIS 4D workstations (ARC-12783, ARC-12782). Silicon Graphics Iris, IRIS 4D, and IRIS 2xxx/3xxx are trademarks of Silicon Graphics Incorporated. VAX and VMS are trademarks of Digital Electronics Corporation. DISSPLA is a trademark of Computer Associates. CRAY 2 and UNICOS are trademarks of CRAY Research, Incorporated. CONVEX is a trademark of Convex Computer Corporation. Alliant is a trademark of Alliant. Apollo and GMR3D are trademarks of Hewlett-Packard, Incorporated. UNIX is a registered trademark of AT&T.

  4. Robust patella motion tracking using intensity-based 2D-3D registration on dynamic bi-plane fluoroscopy: towards quantitative assessment in MPFL reconstruction surgery

    NASA Astrophysics Data System (ADS)

    Otake, Yoshito; Esnault, Matthieu; Grupp, Robert; Kosugi, Shinichi; Sato, Yoshinobu

    2016-03-01

    The determination of in vivo motion of multiple-bones using dynamic fluoroscopic images and computed tomography (CT) is useful for post-operative assessment of orthopaedic surgeries such as medial patellofemoral ligament reconstruction. We propose a robust method to measure the 3D motion of multiple rigid objects with high accuracy using a series of bi-plane fluoroscopic images and a multi-resolution, intensity-based, 2D-3D registration. A Covariance Matrix Adaptation Evolution Strategy (CMA-ES) optimizer was used with a gradient correlation similarity metric. Four approaches to register three rigid objects (femur, tibia-fibula and patella) were implemented: 1) an individual bone approach registering one bone at a time, each with optimization of a six degrees of freedom (6DOF) parameter, 2) a sequential approach registering one bone at a time but using the previous bone results as the background in DRR generation, 3) a simultaneous approach registering all the bones together (18DOF) and 4) a combination of the sequential and the simultaneous approaches. These approaches were compared in experiments using simulated images generated from the CT of a healthy volunteer and measured fluoroscopic images. Over the 120 simulated frames of motion, the simultaneous approach showed improved registration accuracy compared to the individual approach: with less than 0.68mm root-mean-square error (RMSE) for translation and less than 1.12° RMSE for rotation. A robustness evaluation was conducted with 45 trials of a randomly perturbed initialization showed that the sequential approach improved robustness significantly (74% success rate) compared to the individual bone approach (34% success) for patella registration (femur and tibia-fibula registration had a 100% success rate with each approach).

  5. Europeana and 3D

    NASA Astrophysics Data System (ADS)

    Pletinckx, D.

    2011-09-01

    The current 3D hype creates a lot of interest in 3D. People go to 3D movies, but are we ready to use 3D in our homes, in our offices, in our communication? Are we ready to deliver real 3D to a general public and use interactive 3D in a meaningful way to enjoy, learn, communicate? The CARARE project is realising this for the moment in the domain of monuments and archaeology, so that real 3D of archaeological sites and European monuments will be available to the general public by 2012. There are several aspects to this endeavour. First of all is the technical aspect of flawlessly delivering 3D content over all platforms and operating systems, without installing software. We have currently a working solution in PDF, but HTML5 will probably be the future. Secondly, there is still little knowledge on how to create 3D learning objects, 3D tourist information or 3D scholarly communication. We are still in a prototype phase when it comes to integrate 3D objects in physical or virtual museums. Nevertheless, Europeana has a tremendous potential as a multi-facetted virtual museum. Finally, 3D has a large potential to act as a hub of information, linking to related 2D imagery, texts, video, sound. We describe how to create such rich, explorable 3D objects that can be used intuitively by the generic Europeana user and what metadata is needed to support the semantic linking.

  6. 3-D adaptive nonlinear complex-diffusion despeckling filter.

    PubMed

    Rodrigues, Pedro; Bernardes, Rui

    2012-12-01

    This work aims to improve the process of speckle noise reduction while preserving edges and other relevant features through filter expansion from 2-D to 3-D. Despeckling is very important for data visual inspection and as a preprocessing step for other algorithms, as they are usually notably influenced by speckle noise. To that intent, a 3-D approach is proposed for the adaptive complex-diffusion filter. This 3-D iterative filter was applied to spectral-domain optical coherence tomography medical imaging volumes of the human retina and a quantitative evaluation of the results was performed to allow a demonstration of the better performance of the 3-D over the 2-D filtering and to choose the best total diffusion time. In addition, we propose a fast graphical processing unit parallel implementation so that the filter can be used in a clinical setting.

  7. 3-D Animation of Typhoon Bopha

    NASA Video Gallery

    This 3-D animation of NASA's TRMM satellite data showed Typhoon Bopha tracking over the Philippines on Dec. 3 and moving into the Sulu Sea on Dec. 4, 2012. TRMM saw heavy rain (red) was falling at ...

  8. Monte-Carlo Simulation of Heavy Ion Track Structure Calculation of Local Dose and 3D Time Evolution of Radiolytic Species

    NASA Technical Reports Server (NTRS)

    Plante, Ianik; Cucinotta, Francis A.

    2010-01-01

    Heavy ions have gained considerable importance in radiotherapy due to their advantageous dose distribution profile and high Relative Biological Effectiveness (RBE). Heavy ions are difficult to produce on Earth, but they are present in space and it is impossible at this moment to completely shield astronauts from them. The risk of these radiations is poorly understood, which is a concern for a 3-years Mars mission. The effects of radiation are mainly due to DNA damage such as DNA double-strand breaks (DSBs), although non-targeted effects are also very important. DNA can be damaged by the direct interaction of radiation and by reactions with chemical species produced by the radiolysis of water. The energy deposition is of crucial importance to understand biological effects of radiation. Therefore, much effort has been done recently to improve models of radiation tracks.

  9. 3d-3d correspondence revisited

    DOE PAGES

    Chung, Hee -Joong; Dimofte, Tudor; Gukov, Sergei; ...

    2016-04-21

    In fivebrane compactifications on 3-manifolds, we point out the importance of all flat connections in the proper definition of the effective 3d N = 2 theory. The Lagrangians of some theories with the desired properties can be constructed with the help of homological knot invariants that categorify colored Jones polynomials. Higgsing the full 3d theories constructed this way recovers theories found previously by Dimofte-Gaiotto-Gukov. As a result, we also consider the cutting and gluing of 3-manifolds along smooth boundaries and the role played by all flat connections in this operation.

  10. Recent Radar Speckle Observations of Near-Earth Asteroids

    NASA Astrophysics Data System (ADS)

    Busch, Michael W.; Benner, Lance; Brozovic, Marina; Nolan, Michael C.; Springmann, Alessondra; Taylor, Patrick A.

    2014-11-01

    Radar speckle tracking is an observational technique to constrain the spin state of a target object. When illuminated by a monochromatic radar beam, the target scatters light into regions of constructive and destructive interference - a speckle pattern. This pattern moves as the target rotates, with a speed and direction determined by the object’s rotation rate and spin vector. By tracking the motion of a radar speckle pattern between two or more receiving stations, we can constrain the spin state of the target.First applied to measure the spin state of Mercury, since 2008 radar speckle tracking has become one of the standard techniques for radar observations of near-Earth asteroids. We transmit with either of the Arecibo and Goldstone planetary radars, receive with elements of the Very Long Baseline Array or of the Very Large Array, and measure the time lags between the speckle pattern as seen by each station. Starting with the first asteroid observed with speckle observations, 2008 EV5, this technique has allowed us to resolve ambiguities in asteroids’ spin states that delay-Doppler radar imaging and lightcurve observations did not.Recent radar speckle targets have included the near-Earth asteroids 1998 ML14, 2005 WK4, and 2014 HQ124. ML14 was observed with radar shortly after its discovery in 1998, but the earlier radar observations did not yield a unique pole direction constraint. HQ124 is a contact-binary object and was one of the best radar targets of 2014.

  11. Description of an evaluation system for knee kinematics in ligament lesions, by means of optical tracking and 3D tomography☆☆☆

    PubMed Central

    Fernandes, Tiago Lazzaretti; Ribeiro, Douglas Badillo; da Rocha, Diogo Cristo; Albuquerque, Cyro; Pereira, César Augusto Martins; Pedrinelli, André; Hernandez, Arnaldo José

    2014-01-01

    Objective To describe and demonstrate the viability of a method for evaluating knee kinematics, by means of a continuous passive motion (CPM) machine, before and after anterior cruciate ligament (ACL) injury. Methods This study was conducted on a knee from a cadaver, in a mechanical pivot-shift simulator, with evaluations using optical tracking, and also using computed tomography. Results This study demonstrated the viability of a protocol for measuring the rotation and translation of the knee, using reproducible and objective tools (error < 0.2 mm). The mechanized provocation system of the pivot-shift test was independent of the examiner and always allowed the same angular velocity and traction of 20 N throughout the movement. Conclusion The clinical relevance of this method lies in making inferences about the in vivo behavior of a knee with an ACL injury and providing greater methodological quality in future studies for measuring surgical techniques with grafts in relatively close positions. PMID:26229854

  12. Speckle-field digital holographic microscopy

    PubMed Central

    Park, YongKeun; Choi, Wonshik; Yaqoob, Zahid; Dasari, Ramachandra; Badizadegan, Kamran; Feld, Michael S.

    2010-01-01

    The use of coherent light in conventional holographic phase microscopy (HPM) poses three major drawbacks: poor spatial resolution, weak depth sectioning, and fixed pattern noise due to unwanted diffraction. Here, we report a technique which can overcome these drawbacks, but maintains the advantage of phase microscopy - high contrast live cell imaging and 3D imaging. A speckle beam of a complex spatial pattern is used for illumination to reduce fixed pattern noise and to improve optical sectioning capability. By recording of the electric field of speckle, we demonstrate high contrast 3D live cell imaging without the need for axial scanning - neither objective lens nor sample stage. This technique has great potential in studying biological samples with improved sensitivity, resolution and optical sectioning capability. PMID:19654630

  13. Stochastic speckle noise compensation in optical coherence tomography using non-stationary spline-based speckle noise modelling.

    PubMed

    Cameron, Andrew; Lui, Dorothy; Boroomand, Ameneh; Glaister, Jeffrey; Wong, Alexander; Bizheva, Kostadinka

    2013-01-01

    Optical coherence tomography (OCT) allows for non-invasive 3D visualization of biological tissue at cellular level resolution. Often hindered by speckle noise, the visualization of important biological tissue details in OCT that can aid disease diagnosis can be improved by speckle noise compensation. A challenge with handling speckle noise is its inherent non-stationary nature, where the underlying noise characteristics vary with the spatial location. In this study, an innovative speckle noise compensation method is presented for handling the non-stationary traits of speckle noise in OCT imagery. The proposed approach centers on a non-stationary spline-based speckle noise modeling strategy to characterize the speckle noise. The novel method was applied to ultra high-resolution OCT (UHROCT) images of the human retina and corneo-scleral limbus acquired in-vivo that vary in tissue structure and optical properties. Test results showed improved performance of the proposed novel algorithm compared to a number of previously published speckle noise compensation approaches in terms of higher signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR) and better overall visual assessment.

  14. Extracting full-field dynamic strain on a wind turbine rotor subjected to arbitrary excitations using 3D point tracking and a modal expansion technique

    NASA Astrophysics Data System (ADS)

    Baqersad, Javad; Niezrecki, Christopher; Avitabile, Peter

    2015-09-01

    Health monitoring of rotating structures such as wind turbines and helicopter rotors is generally performed using conventional sensors that provide a limited set of data at discrete locations near or on the hub. These sensors usually provide no data on the blades or inside them where failures might occur. Within this paper, an approach was used to extract the full-field dynamic strain on a wind turbine assembly subject to arbitrary loading conditions. A three-bladed wind turbine having 2.3-m long blades was placed in a semi-built-in boundary condition using a hub, a machining chuck, and a steel block. For three different test cases, the turbine was excited using (1) pluck testing, (2) random impacts on blades with three impact hammers, and (3) random excitation by a mechanical shaker. The response of the structure to the excitations was measured using three-dimensional point tracking. A pair of high-speed cameras was used to measure displacement of optical targets on the structure when the blades were vibrating. The measured displacements at discrete locations were expanded and applied to the finite element model of the structure to extract the full-field dynamic strain. The results of the paper show an excellent correlation between the strain predicted using the proposed approach and the strain measured with strain-gages for each of the three loading conditions. The approach used in this paper to predict the strain showed higher accuracy than the digital image correlation technique. The new expansion approach is able to extract dynamic strain all over the entire structure, even inside the structure beyond the line of sight of the measurement system. Because the method is based on a non-contacting measurement approach, it can be readily applied to a variety of structures having different boundary and operating conditions, including rotating blades.

  15. 3D and Education

    NASA Astrophysics Data System (ADS)

    Meulien Ohlmann, Odile

    2013-02-01

    Today the industry offers a chain of 3D products. Learning to "read" and to "create in 3D" becomes an issue of education of primary importance. 25 years professional experience in France, the United States and Germany, Odile Meulien set up a personal method of initiation to 3D creation that entails the spatial/temporal experience of the holographic visual. She will present some different tools and techniques used for this learning, their advantages and disadvantages, programs and issues of educational policies, constraints and expectations related to the development of new techniques for 3D imaging. Although the creation of display holograms is very much reduced compared to the creation of the 90ies, the holographic concept is spreading in all scientific, social, and artistic activities of our present time. She will also raise many questions: What means 3D? Is it communication? Is it perception? How the seeing and none seeing is interferes? What else has to be taken in consideration to communicate in 3D? How to handle the non visible relations of moving objects with subjects? Does this transform our model of exchange with others? What kind of interaction this has with our everyday life? Then come more practical questions: How to learn creating 3D visualization, to learn 3D grammar, 3D language, 3D thinking? What for? At what level? In which matter? for whom?

  16. Studies of Grounding Line Migration Over Rutofrd Ice Stream Using 3D Short Repeat-Time Series From Multi-Track InSAR Acquisitions.

    NASA Astrophysics Data System (ADS)

    Milillo, P.; Minchew, B. M.; Riel, B. V.; Simons, M.; Gardner, A. S.; Agram, P. S.

    2015-12-01

    It has long been known that basal mechanics of ice streams are sensitive to short- timescale hourly to seasonal forcings, such as water pressure fluctuations and tidal loading as well as long-timescale (yearly to decadal) thinning. Designing SAR short repeat time observations to cover nearly an entire test-site in Antarctica from ascending and descending orbital directions, using every available SAR satellite is fundamental for understanding a new class of phenomena, underlying the physics of glaciers and ice streams. Understanding grounding-line dynamics is necessary for predictions of long-term ice-sheet stability. However, despite growing observations of the tidal influence on grounding-line migration, this short-timescale migration is poorly understood, with most modeling attempts assuming beam theory to calculate displacements. Knowing the position of the grounding line with accuracy is important for the global mass balance of ice sheets or for quantitatively modeling the mechanical interaction between ice shelves and ice sheets. Here we present a general method for retrieving three dimensional displacement vector given a set of multiple tracks, multiple geometry SAR acquisitions. The algorithm extends the single line of sight mathematical framework to the four spatial and temporal dimensions including both range and azimuth measurements. We designed COSMO-SkyMed (CSK) observations of Rutford Ice Stream to cover nearly the grounding zone from ascending and descending orbital directions using every available CSK satellite This spatially comprehensive observational scheme allowed us to derive time series of the 3-dimensional surface displacement for the grounding zone, facilitating studies of ice stream mechanics and tidally induced grounding line migrations with unprecedented spatial extent and temporal resolution. Having a constellation with occasional 1- day repeat time and an average 4-days repeat time is beneficial when looking at displacements of more than

  17. High speed 3D surface inspection with digital holography

    NASA Astrophysics Data System (ADS)

    Brunn, Andreas; Aspert, Nicolas; Cuche, Etienne; Emery, Yves; Ettemeyer, Andreas

    2013-01-01

    Digital holography has proven its ability to acquire high accuracy full field 3D data with one single image acquisition. This means that in principle this technique offers the chance to perform 3D serial inspection processes, as well. However, one limitation in digital holography is its limited ability to measure rough surfaces. In the presence of rough surfaces, the magnification of the image has to be increased to capture the required phase information on each camera pixel. However, this leads to significant reduction of inspection speed. If low magnification is selected, the rough surface produces speckles which cannot be treated properly by digital holography algorithms. In this paper, we describe the extension of digital holography to rough surface applications using speckle interferometry technique. This technique is capable of fast inspection of rough surfaces with sub-micrometer accuracy. The principle of this approach is shown and a practical application for 3D surface inspection of wafer cutting processes is given.

  18. Multifractals and dynamic speckle

    NASA Astrophysics Data System (ADS)

    Federico, Alejandro; Kaufmann, Guillermo H.

    2006-09-01

    In recent years, the fractal theory has been applied to a wide variety of scientific problems. However, this approach has not been used to study dynamic processes through the analysis of temporal sequences of speckle patterns. In this work we present a study of the dynamic speckle phenomenon based on the multifractal theory. This study is carried out by calculating the Hausdorff dimension of the set of singularities of the Holder exponent. These parameters are determined from the maxima of the wavelet transform modulus of the scattered light intensity along the time axis, for each pixel of the sequence of speckle images. Calculations conducted on experimental data evidence a multifractal structure in the case of a fast drying paint and a bruised fruit. We extend this result by using a synthetic model, which reproduces quite well the first and second spatial statistics of the speckle intensity as well as the correlation coefficient evaluated from a temporal sequence of speckle patterns.

  19. Suppression of Speckles at High Adaptive Correction Using Speckle Symmetry

    NASA Technical Reports Server (NTRS)

    Bloemhof, Eric E.

    2006-01-01

    Focal-plane speckles set important sensitivity limits on ground- or space-based imagers and coronagraphs that may be used to search for faint companions, perhaps ultimately including exoplanets, around stars. As speckles vary with atmospheric fluctuations or with drifting beamtrain aberrations, they contribute speckle noise proportional to their full amplitude. Schemes to suppress speckles are thus of great interest. At high adaptive correction, speckles organize into species, represented by algebraic terms in the expansion of the phase exponential, that have distinct spatial symmetry, even or odd, under spatial inversion. Filtering speckle patterns by symmetry may eliminate a disproportionate fraction of the speckle noise while blocking (only) half of the image signal from the off-axis companion being sought. The fraction of speckle power and hence of speckle noise in each term will vary with degree of correction, and so also will the net symmetry in the speckle pattern.

  20. Intraoperative image-based multiview 2D/3D registration for image-guided orthopaedic surgery: incorporation of fiducial-based C-arm tracking and GPU-acceleration.

    PubMed

    Otake, Yoshito; Armand, Mehran; Armiger, Robert S; Kutzer, Michael D; Basafa, Ehsan; Kazanzides, Peter; Taylor, Russell H

    2012-04-01

    Intraoperative patient registration may significantly affect the outcome of image-guided surgery (IGS). Image-based registration approaches have several advantages over the currently dominant point-based direct contact methods and are used in some industry solutions in image-guided radiation therapy with fixed X-ray gantries. However, technical challenges including geometric calibration and computational cost have precluded their use with mobile C-arms for IGS. We propose a 2D/3D registration framework for intraoperative patient registration using a conventional mobile X-ray imager combining fiducial-based C-arm tracking and graphics processing unit (GPU)-acceleration. The two-stage framework 1) acquires X-ray images and estimates relative pose between the images using a custom-made in-image fiducial, and 2) estimates the patient pose using intensity-based 2D/3D registration. Experimental validations using a publicly available gold standard dataset, a plastic bone phantom and cadaveric specimens have been conducted. The mean target registration error (mTRE) was 0.34 ± 0.04 mm (success rate: 100%, registration time: 14.2 s) for the phantom with two images 90° apart, and 0.99 ± 0.41 mm (81%, 16.3 s) for the cadaveric specimen with images 58.5° apart. The experimental results showed the feasibility of the proposed registration framework as a practical alternative for IGS routines.

  1. Intraoperative Image-based Multiview 2D/3D Registration for Image-Guided Orthopaedic Surgery: Incorporation of Fiducial-Based C-Arm Tracking and GPU-Acceleration

    PubMed Central

    Armand, Mehran; Armiger, Robert S.; Kutzer, Michael D.; Basafa, Ehsan; Kazanzides, Peter; Taylor, Russell H.

    2012-01-01

    Intraoperative patient registration may significantly affect the outcome of image-guided surgery (IGS). Image-based registration approaches have several advantages over the currently dominant point-based direct contact methods and are used in some industry solutions in image-guided radiation therapy with fixed X-ray gantries. However, technical challenges including geometric calibration and computational cost have precluded their use with mobile C-arms for IGS. We propose a 2D/3D registration framework for intraoperative patient registration using a conventional mobile X-ray imager combining fiducial-based C-arm tracking and graphics processing unit (GPU)-acceleration. The two-stage framework 1) acquires X-ray images and estimates relative pose between the images using a custom-made in-image fiducial, and 2) estimates the patient pose using intensity-based 2D/3D registration. Experimental validations using a publicly available gold standard dataset, a plastic bone phantom and cadaveric specimens have been conducted. The mean target registration error (mTRE) was 0.34 ± 0.04 mm (success rate: 100%, registration time: 14.2 s) for the phantom with two images 90° apart, and 0.99 ± 0.41 mm (81%, 16.3 s) for the cadaveric specimen with images 58.5° apart. The experimental results showed the feasibility of the proposed registration framework as a practical alternative for IGS routines. PMID:22113773

  2. Flux or speed? Examining speckle contrast imaging of vascular flows

    PubMed Central

    Kazmi, S. M. Shams; Faraji, Ehssan; Davis, Mitchell A.; Huang, Yu-Yen; Zhang, Xiaojing J.; Dunn, Andrew K.

    2015-01-01

    Speckle contrast imaging enables rapid mapping of relative blood flow distributions using camera detection of back-scattered laser light. However, speckle derived flow measures deviate from direct measurements of erythrocyte speeds by 47 ± 15% (n = 13 mice) in vessels of various calibers. Alternatively, deviations with estimates of volumetric flux are on average 91 ± 43%. We highlight and attempt to alleviate this discrepancy by accounting for the effects of multiple dynamic scattering with speckle imaging of microfluidic channels of varying sizes and then with red blood cell (RBC) tracking correlated speckle imaging of vascular flows in the cerebral cortex. By revisiting the governing dynamic light scattering models, we test the ability to predict the degree of multiple dynamic scattering across vessels in order to correct for the observed discrepancies between relative RBC speeds and multi-exposure speckle imaging estimates of inverse correlation times. The analysis reveals that traditional speckle contrast imagery of vascular flows is neither a measure of volumetric flux nor particle speed, but rather the product of speed and vessel diameter. The corrected speckle estimates of the relative RBC speeds have an average 10 ± 3% deviation in vivo with those obtained from RBC tracking. PMID:26203384

  3. 3D Imaging.

    ERIC Educational Resources Information Center

    Hastings, S. K.

    2002-01-01

    Discusses 3 D imaging as it relates to digital representations in virtual library collections. Highlights include X-ray computed tomography (X-ray CT); the National Science Foundation (NSF) Digital Library Initiatives; output peripherals; image retrieval systems, including metadata; and applications of 3 D imaging for libraries and museums. (LRW)

  4. Active illuminated space object imaging and tracking simulation

    NASA Astrophysics Data System (ADS)

    Yue, Yufang; Xie, Xiaogang; Luo, Wen; Zhang, Feizhou; An, Jianzhu

    2016-10-01

    Optical earth imaging simulation of a space target in orbit and it's extraction in laser illumination condition were discussed. Based on the orbit and corresponding attitude of a satellite, its 3D imaging rendering was built. General simulation platform was researched, which was adaptive to variable 3D satellite models and relative position relationships between satellite and earth detector system. Unified parallel projection technology was proposed in this paper. Furthermore, we denoted that random optical distribution in laser-illuminated condition was a challenge for object discrimination. Great randomicity of laser active illuminating speckles was the primary factor. The conjunction effects of multi-frame accumulation process and some tracking methods such as Meanshift tracking, contour poid, and filter deconvolution were simulated. Comparison of results illustrates that the union of multi-frame accumulation and contour poid was recommendable for laser active illuminated images, which had capacities of high tracking precise and stability for multiple object attitudes.

  5. Kitt Peak speckle camera

    NASA Technical Reports Server (NTRS)

    Breckinridge, J. B.; Mcalister, H. A.; Robinson, W. G.

    1979-01-01

    The speckle camera in regular use at Kitt Peak National Observatory since 1974 is described in detail. The design of the atmospheric dispersion compensation prisms, the use of film as a recording medium, the accuracy of double star measurements, and the next generation speckle camera are discussed. Photographs of double star speckle patterns with separations from 1.4 sec of arc to 4.7 sec of arc are shown to illustrate the quality of image formation with this camera, the effects of seeing on the patterns, and to illustrate the isoplanatic patch of the atmosphere.

  6. Fish body surface data measurement based on 3D digital image correlation

    NASA Astrophysics Data System (ADS)

    Jiang, Ming; Qian, Chen; Yang, Wenkai

    2016-01-01

    To film the moving fish in the glass tank, light will be bent at the interface of air and glass, glass and water. Based on binocular stereo vision and refraction principle, we establish a mathematical model of 3D image correlation to reconstruct the 3D coordinates of samples in the water. Marking speckle in fish surface, a series of real-time speckle images of swimming fish will be obtained by two high-speed cameras, and instantaneous 3D shape, strain, displacement etc. of fish will be reconstructed.

  7. Modeling of multi-view 3D freehand radio frequency ultrasound.

    PubMed

    Klein, T; Hansson, M; Navab, Nassir

    2012-01-01

    Nowadays ultrasound (US) examinations are typically performed with conventional machines providing two dimensional imagery. However, there exist a multitude of applications where doctors could benefit from three dimensional ultrasound providing better judgment, due to the extended spatial view. 3D freehand US allows acquisition of images by means of a tracking device attached to the ultrasound transducer. Unfortunately, view dependency makes the 3D representation of ultrasound a non-trivial task. To address this we model speckle statistics, in envelope-detected radio frequency (RF) data, using a finite mixture model (FMM), assuming a parametric representation of data, in which the multiple views are treated as components of the FMM. The proposed model is show-cased with registration, using an ultrasound specific distribution based pseudo-distance, and reconstruction tasks, performed on the manifold of Gamma model parameters. Example field of application is neurology using transcranial US, as this domain requires high accuracy and data systematically features low SNR, making intensity based registration difficult. In particular, 3D US can be specifically used to improve differential diagnosis of Parkinson's disease (PD) compared to conventional approaches and is therefore of high relevance for future application.

  8. AE3D

    SciTech Connect

    Spong, Donald A

    2016-06-20

    AE3D solves for the shear Alfven eigenmodes and eigenfrequencies in a torodal magnetic fusion confinement device. The configuration can be either 2D (e.g. tokamak, reversed field pinch) or 3D (e.g. stellarator, helical reversed field pinch, tokamak with ripple). The equations solved are based on a reduced MHD model and sound wave coupling effects are not currently included.

  9. 3D ultrafast ultrasound imaging in vivo.

    PubMed

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-07

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra--and inter-observer variability.

  10. 3D ultrafast ultrasound imaging in vivo

    NASA Astrophysics Data System (ADS)

    Provost, Jean; Papadacci, Clement; Esteban Arango, Juan; Imbault, Marion; Fink, Mathias; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-10-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in 3D based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32  ×  32 matrix-array probe. Its ability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3D Shear-Wave Imaging, 3D Ultrafast Doppler Imaging, and, finally, 3D Ultrafast combined Tissue and Flow Doppler Imaging. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3D Ultrafast Doppler was used to obtain 3D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, at thousands of volumes per second, the complex 3D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, as well as the 3D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3D Ultrafast Ultrasound Imaging for the 3D mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra—and inter-observer variability.

  11. Speckle interferometry of asteroids

    NASA Technical Reports Server (NTRS)

    Drummond, Jack

    1988-01-01

    This final report for NASA Contract NAGw-867 consists of abstracts of the first three papers in a series of four appearing in Icarus that were funded by the preceding contract NAGw-224: (1) Speckle Interferometry of Asteroids I. 433 Eros; (2) Speckle Interferometry of Asteroids II. 532 Herculina; (3) Speckle Interferometry of Asteroids III. 511 Davida and its Photometry; and the fourth abstract attributed to NAGw-867, (4) Speckle Interferometry of Asteroids IV. Reconstructed images of 4 Vesta; and a review of the results from the asteroid interferometry program at Steward Observatory prepared for the Asteroids II book, (5) Speckle Interferometry of Asteroids. Two papers on asteroids, indirectly related to speckle interferometry, were written in part under NAGw-867. One is in press and its abstract is included here: Photometric Geodesy of Main-Belt Asteroids. II. Analysis of Lightcurves for Poles, Periods and Shapes; and the other paper, Triaxial Ellipsoid Dimensions and Rotational Pole of 2 Pallas from Two Stellar Occultations, is included in full.

  12. Stellar speckle interferometry and speckle holography at low light levels

    NASA Astrophysics Data System (ADS)

    Weigelt, G. P.

    1980-01-01

    A brief review of speckle interferometry and speckle holography techniques is presented, along with examples of each. The application of speckle interferometry to the observation of objects near a point source, i.e., the reconstruction of direct images from speckle interferograms, is discussed, as is the application of the technique for observing faint astronomical objects, such as galactic nuclei and quasars, by measuring the single photon events in speckle interferograms. The two types of measurements were performed using the ESO 3.6 m telescope and other telescopes. The techniques have been used to overcome atmospheric image degradation completely, making the resolution of the speckle measurements about 30 times higher than that of ordinary astrophotography. Speckle interferometry up to 14th magnitude has been achieved, and the measurements yielded high resolution autocorrelations of the objects. Direct images were deconvolved using the speckle holography technique.

  13. Study Of Ho Lo-Speckle Interferometry

    NASA Astrophysics Data System (ADS)

    Chen, Jiabi

    1987-10-01

    Holo-speckle interferometry (HSI), as a 3-D displacement measuring method is studied in this paper. Three types of HSI are given. The average intensity distributions of its holographic and speckle interference fringes on the output planes are derived. The range of mea-surement and the problem of repositioning holograms for two-reference-beam HSI are disscussed. The results show that the upper limit of out-of-plane displacement is related to the parameters of the optical system and the in-plane displacement of specimen but the upper limit of in-plane displacement is determined by the paremeters only. The rigid body rotation of hologram in reconstruction process of two-reference-beam HSI influences the formation of interference fringes but the rigid body traslation does not have the influence.

  14. 3-D Seismic Interpretation

    NASA Astrophysics Data System (ADS)

    Moore, Gregory F.

    2009-05-01

    This volume is a brief introduction aimed at those who wish to gain a basic and relatively quick understanding of the interpretation of three-dimensional (3-D) seismic reflection data. The book is well written, clearly illustrated, and easy to follow. Enough elementary mathematics are presented for a basic understanding of seismic methods, but more complex mathematical derivations are avoided. References are listed for readers interested in more advanced explanations. After a brief introduction, the book logically begins with a succinct chapter on modern 3-D seismic data acquisition and processing. Standard 3-D acquisition methods are presented, and an appendix expands on more recent acquisition techniques, such as multiple-azimuth and wide-azimuth acquisition. Although this chapter covers the basics of standard time processing quite well, there is only a single sentence about prestack depth imaging, and anisotropic processing is not mentioned at all, even though both techniques are now becoming standard.

  15. Radiochromic 3D Detectors

    NASA Astrophysics Data System (ADS)

    Oldham, Mark

    2015-01-01

    Radiochromic materials exhibit a colour change when exposed to ionising radiation. Radiochromic film has been used for clinical dosimetry for many years and increasingly so recently, as films of higher sensitivities have become available. The two principle advantages of radiochromic dosimetry include greater tissue equivalence (radiologically) and the lack of requirement for development of the colour change. In a radiochromic material, the colour change arises direct from ionising interactions affecting dye molecules, without requiring any latent chemical, optical or thermal development, with important implications for increased accuracy and convenience. It is only relatively recently however, that 3D radiochromic dosimetry has become possible. In this article we review recent developments and the current state-of-the-art of 3D radiochromic dosimetry, and the potential for a more comprehensive solution for the verification of complex radiation therapy treatments, and 3D dose measurement in general.

  16. 3D Ultrafast Ultrasound Imaging In Vivo

    PubMed Central

    Provost, Jean; Papadacci, Clement; Arango, Juan Esteban; Imbault, Marion; Gennisson, Jean-Luc; Tanter, Mickael; Pernot, Mathieu

    2014-01-01

    Very high frame rate ultrasound imaging has recently allowed for the extension of the applications of echography to new fields of study such as the functional imaging of the brain, cardiac electrophysiology, and the quantitative real-time imaging of the intrinsic mechanical properties of tumors, to name a few, non-invasively and in real time. In this study, we present the first implementation of Ultrafast Ultrasound Imaging in three dimensions based on the use of either diverging or plane waves emanating from a sparse virtual array located behind the probe. It achieves high contrast and resolution while maintaining imaging rates of thousands of volumes per second. A customized portable ultrasound system was developed to sample 1024 independent channels and to drive a 32×32 matrix-array probe. Its capability to track in 3D transient phenomena occurring in the millisecond range within a single ultrafast acquisition was demonstrated for 3-D Shear-Wave Imaging, 3-D Ultrafast Doppler Imaging and finally 3D Ultrafast combined Tissue and Flow Doppler. The propagation of shear waves was tracked in a phantom and used to characterize its stiffness. 3-D Ultrafast Doppler was used to obtain 3-D maps of Pulsed Doppler, Color Doppler, and Power Doppler quantities in a single acquisition and revealed, for the first time, the complex 3-D flow patterns occurring in the ventricles of the human heart during an entire cardiac cycle, and the 3-D in vivo interaction of blood flow and wall motion during the pulse wave in the carotid at the bifurcation. This study demonstrates the potential of 3-D Ultrafast Ultrasound Imaging for the 3-D real-time mapping of stiffness, tissue motion, and flow in humans in vivo and promises new clinical applications of ultrasound with reduced intra- and inter-observer variability. PMID:25207828

  17. Bootstrapping 3D fermions

    DOE PAGES

    Iliesiu, Luca; Kos, Filip; Poland, David; ...

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  18. Bootstrapping 3D fermions

    SciTech Connect

    Iliesiu, Luca; Kos, Filip; Poland, David; Pufu, Silviu S.; Simmons-Duffin, David; Yacoby, Ran

    2016-03-17

    We study the conformal bootstrap for a 4-point function of fermions <ψψψψ> in 3D. We first introduce an embedding formalism for 3D spinors and compute the conformal blocks appearing in fermion 4-point functions. Using these results, we find general bounds on the dimensions of operators appearing in the ψ × ψ OPE, and also on the central charge CT. We observe features in our bounds that coincide with scaling dimensions in the GrossNeveu models at large N. Finally, we also speculate that other features could coincide with a fermionic CFT containing no relevant scalar operators.

  19. Venus in 3D

    NASA Technical Reports Server (NTRS)

    Plaut, Jeffrey J.

    1993-01-01

    Stereographic images of the surface of Venus which enable geologists to reconstruct the details of the planet's evolution are discussed. The 120-meter resolution of these 3D images make it possible to construct digital topographic maps from which precise measurements can be made of the heights, depths, slopes, and volumes of geologic structures.

  20. 3D photoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Carson, Jeffrey J. L.; Roumeliotis, Michael; Chaudhary, Govind; Stodilka, Robert Z.; Anastasio, Mark A.

    2010-06-01

    Our group has concentrated on development of a 3D photoacoustic imaging system for biomedical imaging research. The technology employs a sparse parallel detection scheme and specialized reconstruction software to obtain 3D optical images using a single laser pulse. With the technology we have been able to capture 3D movies of translating point targets and rotating line targets. The current limitation of our 3D photoacoustic imaging approach is its inability ability to reconstruct complex objects in the field of view. This is primarily due to the relatively small number of projections used to reconstruct objects. However, in many photoacoustic imaging situations, only a few objects may be present in the field of view and these objects may have very high contrast compared to background. That is, the objects have sparse properties. Therefore, our work had two objectives: (i) to utilize mathematical tools to evaluate 3D photoacoustic imaging performance, and (ii) to test image reconstruction algorithms that prefer sparseness in the reconstructed images. Our approach was to utilize singular value decomposition techniques to study the imaging operator of the system and evaluate the complexity of objects that could potentially be reconstructed. We also compared the performance of two image reconstruction algorithms (algebraic reconstruction and l1-norm techniques) at reconstructing objects of increasing sparseness. We observed that for a 15-element detection scheme, the number of measureable singular vectors representative of the imaging operator was consistent with the demonstrated ability to reconstruct point and line targets in the field of view. We also observed that the l1-norm reconstruction technique, which is known to prefer sparseness in reconstructed images, was superior to the algebraic reconstruction technique. Based on these findings, we concluded (i) that singular value decomposition of the imaging operator provides valuable insight into the capabilities of

  1. Subjective speckle suppression in laser-based stereo photogrammetry

    NASA Astrophysics Data System (ADS)

    Stark, Andreas Walter; Wong, Eugene; Weigel, Daniel; Babovsky, Holger; Schott, Thomas; Kowarschik, Richard

    2016-12-01

    The use of objective speckles as patterns is of high interest for the ongoing development of stereo photogrammetry. The depth of focus of the projected speckle patterns, which can be found to be several meters, can hardly be matched by other projection principles. On the downside, the use of coherent light leads to subjective speckles generated by the rough surface of the object under test. This effect decreases the accuracy under which objects can be reconstructed. We show how laser-based stereo photogrammetry can be adjusted to increase the measurement accuracy of three-dimensional (3-D)-surface measurements while preserving the advantages of speckles projection. Therefore, we present a method to decrease the contrast of subjective speckles in the images by pixel-wise shifting the cameras orthogonally to their viewing direction and back shifting the taken images numerically, accordingly. This leads to an increase in 3-D-reconstruction quality, as seen in a decrease in standard deviation, peak-to-valley value and in an increase in the number of reconstructed points for measured test objects.

  2. Changes in mitral annular morphology and function in young patients with type 1 diabetes mellitus—results from the three-dimensional speckle tracking echocardiographic MAGYAR-Path Study

    PubMed Central

    Piros, Györgyike Ágnes; Domsik, Péter; Kalapos, Anita; Lengyel, Csaba; Várkonyi, Tamás T.; Orosz, Andrea; Forster, Tamás

    2015-01-01

    Background Alterations in mitral annular size and function could be demonstrated in cardiomyopathies and ischaemic heart disease. The present study was designed to evaluate mitral annulus (MA) morphology and function in young type 1 diabetes mellitus (T1DM) patients by three-dimensional speckle tracking echocardiography (3DSTE) and to compare their results to matched healthy controls. Methods The study comprised 18 patients with T1DM (mean age: 33.0±8.0 years). Their results were compared to that of 20 age- and gender-matched healthy controls (mean age: 37.8±10.9 years). Complete two-dimensional (2D) Doppler echocardiography and 3DSTE have been performed in all cases. Results No significant differences could be demonstrated in demographic and standard echocardiographic parameters between the groups. Significantly enlarged diastolic MA diameter (2.87±0.27 mm vs. 2.58±0.32 mm, P=0.01), MA diameter index 1.61±0.20 cm/m2 vs. 1.30±0.39 cm/m2, P=0.008, and MA area index (4.81±0.88 cm2/m2 vs. 3.91±1.35 cm2/m2, P=0.03) could be demonstrated in T1DM together with augmented MA fractional shortening (28.64±9.63% vs. 20.35±12.50%, P=0.05). Conclusions Early alterations in MA size and function could be demonstrated in young patients with T1DM by 3DSTE. PMID:26807363

  3. Association of left atrial reservoir function with left atrial structural remodeling related to left ventricular dysfunction in asymptomatic patients with hypertension: evaluation by two-dimensional speckle-tracking echocardiography.

    PubMed

    Miyoshi, Hirokazu; Oishi, Yoshifumi; Mizuguchi, Yukio; Iuchi, Arata; Nagase, Norio; Ara, Nusrat; Oki, Takashi

    2015-01-01

    Left atrial (LA) structural and functional abnormalities are vital steps on the pathway toward heart failure with preserved ejection fraction in asymptomatic patients. The purpose of this study was to assess the relationship of LA function, particularly reservoir function, with LA structural remodeling related to the left ventricular (LV) dysfunction in asymptomatic patients with hypertension (HT) using conventional, tissue Doppler, and 2-D speckle-tracking echocardiography. Fifty age-matched healthy individuals and 140 patients with HT, including 75 with LA volume index (LAVI)<29 ml/m2 (normal LA group) and 65 with LAVI≥29 ml/m2 (large LA group), were enrolled. We defined peak early diastolic transmitral flow velocity/peak early diastolic mitral annular motion velocity (E/e')/peak systolic LA strain (S-LAs) as LA diastolic stiffness. The LV mass index, relative LV wall thickness, peak atrial systolic transmitral flow velocity, LA total, active, and passive emptying volume indexes, and E/e'/S-LAs were greatest, and S-LAs, peak early diastolic LA strain, peak systolic LV longitudinal strain and circumferential strain rate, and peak early diastolic LV radial strain rate were lower in the large LA group compared with control and/or normal LA group. Multivariate linear regression analysis revealed that aging, LA remodeling, and LV systolic and diastolic dysfunction are defined as strong predictors related to increased LA diastolic stiffness in the large LA group. HT alters LA dynamics significantly, with resultant increased LA volume and diastolic stiffness related to LV diastolic and systolic dysfunction, even in asymptomatic patients. Earlier treatment with renin–angiotensin system inhibitors may improve abnormal LA-LV interaction in this patient population.

  4. Counter-sniper 3D laser radar

    NASA Astrophysics Data System (ADS)

    Shepherd, Orr; LePage, Andrew J.; Wijntjes, Geert J.; Zehnpfennig, Theodore F.; Sackos, John T.; Nellums, Robert O.

    1999-01-01

    Visidyne, Inc., teaming with Sandia National Laboratories, has developed the preliminary design for an innovative scannerless 3-D laser radar capable of acquiring, tracking, and determining the coordinates of small caliber projectiles in flight with sufficient precision, so their origin can be established by back projecting their tracks to their source. The design takes advantage of the relatively large effective cross-section of a bullet at optical wavelengths. Kay to its implementation is the use of efficient, high- power laser diode arrays for illuminators and an imaging laser receiver using a unique CCD imager design, that acquires the information to establish x, y (angle-angle) and range coordinates for each bullet at very high frame rates. The detection process achieves a high degree of discrimination by using the optical signature of the bullet, solar background mitigation, and track detection. Field measurements and computer simulations have been used to provide the basis for a preliminary design of a robust bullet tracker, the Counter Sniper 3-D Laser Radar. Experimental data showing 3-D test imagery acquired by a lidar with architecture similar to that of the proposed Counter Sniper 3-D Lidar are presented. A proposed Phase II development would yield an innovative, compact, and highly efficient bullet-tracking laser radar. Such a device would meet the needs of not only the military, but also federal, state, and local law enforcement organizations.

  5. Double-pulse digital speckle pattern interferometry for vibration analysis

    NASA Astrophysics Data System (ADS)

    Zhang, Dazhi; Xue, Jingfeng; Chen, Lu; Wen, Juying; Wang, Jingjing

    2014-12-01

    The double-pulse Digital Speckle Pattern Interferometry (DSPI) in the laboratory is established. Two good performances have been achieved at the same time, which is uniform distribution of laser beam energy by space filter and recording two successive pictures by a CCD camera successfully. Then two-dimensional discrete orthogonal wavelet transform method is used for the process of filtering method. By using the DSPI, speckle pattern of a vibrated object is obtained with interval of (2~800)μs, and 3D plot of the transient vibration is achieved. Moreover, good agreements of the mode shapes and displacement are obtained by comparing with Laser Doppler Vibrometer (LDV) .

  6. Extending temporal coherence in speckle interferometry

    NASA Astrophysics Data System (ADS)

    Crespo Contiñas, J. M.; Moreno de las Cuevas, V.; Gallas Torreira, M.; Calizaya Calizaya, M.

    2013-11-01

    Electronic Speckle Pattern Interferometry (ESPI) and Shearography (ESPSI) techniques have been used in the field of non-destructive testing for a long time, providing accuracy, and allowing whole field analysis of pure deformation (ESPI) or the gradient of deformation (ESPSI). One of the major weaknesses of this two techniques is linked to speckle de-correlation. When the deformation process produces a displacement greater than a certain proportion of the speckle size, there is a severe loss of coherence which limits the application of these techniques to processes with strong or fast deformations. In order to avoid this limitation, the use of a dynamically updated reference frame is tested in this work. First, in ESPI and ESPSI setups, a metacrylathe bar is used as specimen for testing procedures, and finally a human jaw bone will be used in an ESPSI setup. One basic and regular-shaped object, the bar, and a structurally 3D complex structure, the human jaw bone, with complex elastic properties are the samples to test.

  7. Twin Peaks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The two hills in the distance, approximately one to two kilometers away, have been dubbed the 'Twin Peaks' and are of great interest to Pathfinder scientists as objects of future study. 3D glasses are necessary to identify surface detail. The white areas on the left hill, called the 'Ski Run' by scientists, may have been formed by hydrologic processes.

    The IMP is a stereo imaging system with color capability provided by 24 selectable filters -- twelve filters per 'eye.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  8. 3D and beyond

    NASA Astrophysics Data System (ADS)

    Fung, Y. C.

    1995-05-01

    This conference on physiology and function covers a wide range of subjects, including the vasculature and blood flow, the flow of gas, water, and blood in the lung, the neurological structure and function, the modeling, and the motion and mechanics of organs. Many technologies are discussed. I believe that the list would include a robotic photographer, to hold the optical equipment in a precisely controlled way to obtain the images for the user. Why are 3D images needed? They are to achieve certain objectives through measurements of some objects. For example, in order to improve performance in sports or beauty of a person, we measure the form, dimensions, appearance, and movements.

  9. 3D Audio System

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Ames Research Center research into virtual reality led to the development of the Convolvotron, a high speed digital audio processing system that delivers three-dimensional sound over headphones. It consists of a two-card set designed for use with a personal computer. The Convolvotron's primary application is presentation of 3D audio signals over headphones. Four independent sound sources are filtered with large time-varying filters that compensate for motion. The perceived location of the sound remains constant. Possible applications are in air traffic control towers or airplane cockpits, hearing and perception research and virtual reality development.

  10. Three Dimensional Speckle Imaging Employing a Frequency-Locked Tunable Diode Laser

    SciTech Connect

    Cannon, Bret D.; Bernacki, Bruce E.; Schiffern, John T.; Mendoza, Albert

    2015-09-01

    We describe a high accuracy frequency stepping method for a tunable diode laser to improve a three dimensional (3D) imaging approach based upon interferometric speckle imaging. The approach, modeled after Takeda, exploits tuning an illumination laser in frequency as speckle interferograms of the object (specklegrams) are acquired at each frequency in a Michelson interferometer. The resulting 3D hypercube of specklegrams encode spatial information in the x-y plane of each image with laser tuning arrayed along its z-axis. We present laboratory data of before and after results showing enhanced 3D imaging resulting from precise laser frequency control.

  11. Modeled and measured image-plane polychromatic speckle contrast

    NASA Astrophysics Data System (ADS)

    Van Zandt, Noah R.; McCrae, Jack E.; Fiorino, Steven T.

    2016-02-01

    The statistical properties of speckle relevant to short- to medium-range (tactical) active tracking involving polychromatic illumination are investigated. A numerical model is developed to allow rapid simulation of speckled images including the speckle contrast reduction effects of illuminator bandwidth, surface slope, and roughness, and the polarization properties of both the source and the reflection. Regarding surface slope (relative orientation of the surface normal and illumination/observation directions), Huntley's theory for speckle contrast, which employs geometrical approximations to decrease computation time, is modified to increase accuracy by incorporation of a geometrical correction factor and better treatment of roughness and polarization. The resulting model shows excellent agreement with more exact theory over a wide range. An experiment is conducted to validate both the numerical model developed here and existing theory. A diode laser source with coherence length of 259±7 μm is reflected off of a silver-coated diffuse surface. Speckle data are gathered for 16 surface slope angles corresponding to speckle contrast between about 0.55 and 1. Taking the measured data as truth, both equations show error mean and standard deviation of less than 3%. Thus, the theory is validated over the range of this experiment.

  12. 3D Surgical Simulation

    PubMed Central

    Cevidanes, Lucia; Tucker, Scott; Styner, Martin; Kim, Hyungmin; Chapuis, Jonas; Reyes, Mauricio; Proffit, William; Turvey, Timothy; Jaskolka, Michael

    2009-01-01

    This paper discusses the development of methods for computer-aided jaw surgery. Computer-aided jaw surgery allows us to incorporate the high level of precision necessary for transferring virtual plans into the operating room. We also present a complete computer-aided surgery (CAS) system developed in close collaboration with surgeons. Surgery planning and simulation include construction of 3D surface models from Cone-beam CT (CBCT), dynamic cephalometry, semi-automatic mirroring, interactive cutting of bone and bony segment repositioning. A virtual setup can be used to manufacture positioning splints for intra-operative guidance. The system provides further intra-operative assistance with the help of a computer display showing jaw positions and 3D positioning guides updated in real-time during the surgical procedure. The CAS system aids in dealing with complex cases with benefits for the patient, with surgical practice, and for orthodontic finishing. Advanced software tools for diagnosis and treatment planning allow preparation of detailed operative plans, osteotomy repositioning, bone reconstructions, surgical resident training and assessing the difficulties of the surgical procedures prior to the surgery. CAS has the potential to make the elaboration of the surgical plan a more flexible process, increase the level of detail and accuracy of the plan, yield higher operative precision and control, and enhance documentation of cases. Supported by NIDCR DE017727, and DE018962 PMID:20816308

  13. Martian terrain - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    An area of rocky terrain near the landing site of the Sagan Memorial Station can be seen in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. This image is part of a 3D 'monster' panorama of the area surrounding the landing site.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  14. 3D Spray Droplet Distributions in Sneezes

    NASA Astrophysics Data System (ADS)

    Techet, Alexandra; Scharfman, Barry; Bourouiba, Lydia

    2015-11-01

    3D spray droplet clouds generated during human sneezing are investigated using the Synthetic Aperture Feature Extraction (SAFE) method, which relies on light field imaging (LFI) and synthetic aperture (SA) refocusing computational photographic techniques. An array of nine high-speed cameras are used to image sneeze droplets and tracked the droplets in 3D space and time (3D + T). An additional high-speed camera is utilized to track the motion of the head during sneezing. In the SAFE method, the raw images recorded by each camera in the array are preprocessed and binarized, simplifying post processing after image refocusing and enabling the extraction of feature sizes and positions in 3D + T. These binary images are refocused using either additive or multiplicative methods, combined with thresholding. Sneeze droplet centroids, radii, distributions and trajectories are determined and compared with existing data. The reconstructed 3D droplet centroids and radii enable a more complete understanding of the physical extent and fluid dynamics of sneeze ejecta. These measurements are important for understanding the infectious disease transmission potential of sneezes in various indoor environments.

  15. Speckles and Shadow Bands

    NASA Astrophysics Data System (ADS)

    Mason, Brian D.

    1995-03-01

    Speckle interferometry has for the past two decades provided a means to measure very accurate relative positions of binary stars, data crucial to the fundamental determination of basic stellar parameters. As a technique for observing small angular separations speckle interferometry is exceeded only by long baseline interferometry (a technique still in infancy) and the observation of lunar occultation phenomena. As the moon passes in front of stars the light coming from those stars is occulted. Occultations of binary stars can determine relative intensities and can measure separations which are comparable to those measured by long-baseline interferometers. The data are difficult to interpret since the measured separation is a projection of the true angular separation and non-standard filters are often used. No complete listing of all occultation measures has been published since the compilation of David Evans (IAU Colloquium No. 62, Current Techniques in Double and Multiple Star Research, Lowell Observatory Bulletin No. 167, 1981, eds. Harrington, R.A. \\& Franz, O.G., Lowell Observatory, Flagstaff). The dissertation presents 772 measures of 357 systems, an increase of 60\\% over the Evans catalog. The methodology of speckle interferometry is presented, followed by 362 re-reduction measures and 253 new measures. The re-reduction measures were cases where prior analysis showed no companion. With improved reduction algorithms, detection frequency significantly increased. One observation in eight previously showing no companion produced a measurable result. Results were obtained with the 1.8-m Perkins telescope of Lowell Observatory, the 2.5-m Hooker telescope of Mt. Wilson Observatory, the 3.8-m Mayall telescope of Kitt Peak National Observatory and the 4.0-m telescope at Cerro Tololo InterAmerican Observatory. All but 130 of the occultation objects have speckle observations. The likelihood of future detection by speckle is considered. An analysis of 131 negative

  16. Superplot3d: an open source GUI tool for 3d trajectory visualisation and elementary processing.

    PubMed

    Whitehorn, Luke J; Hawkes, Frances M; Dublon, Ian An

    2013-09-30

    When acquiring simple three-dimensional (3d) trajectory data it is common to accumulate large coordinate data sets. In order to examine integrity and consistency of object tracking, it is often necessary to rapidly visualise these data. Ordinarily, to achieve this the user must either execute 3d plotting functions in a numerical computing environment or manually inspect data in two dimensions, plotting each individual axis.Superplot3d is an open source MATLAB script which takes tab delineated Cartesian data points in the form x, y, z and time and generates an instant visualization of the object's trajectory in free-rotational three dimensions. Whole trajectories may be instantly presented, allowing for rapid inspection. Executable from the MATLAB command line (or deployable as a compiled standalone application) superplot3d also provides simple GUI controls to obtain rudimentary trajectory information, allow specific visualization of trajectory sections and perform elementary processing.Superplot3d thus provides a framework for non-programmers and programmers alike, to recreate recently acquired 3d object trajectories in rotatable 3d space. It is intended, via the use of a preference driven menu to be flexible and work with output from multiple tracking software systems. Source code and accompanying GUIDE .fig files are provided for deployment and further development.

  17. 3D dynamic holographic display by modulating complex amplitude experimentally.

    PubMed

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

    2013-09-09

    Complex amplitude modulation method is presented theoretically and performed experimentally for three-dimensional (3D) dynamic holographic display with reduced speckle using a single phase-only spatial light modulator. The determination of essential factors is discussed based on the basic principle and theory. The numerical simulations and optical experiments are performed, where the static and animated objects without refinement on the surfaces and without random initial phases are reconstructed successfully. The results indicate that this method can reduce the speckle in reconstructed images effectively; furthermore, it will not cause the internal structure in the reconstructed pixels. Since the complex amplitude modulation is based on the principle of phase-only hologram, it does not need the stringent alignment of pixels. This method can be used for high resolution imaging or measurement in various optical areas.

  18. Laser speckle reduction based on compressive sensing and edge detection

    NASA Astrophysics Data System (ADS)

    Wen, Dong-hai; Jiang, Yue-song; Hua, Hou-qiang; Yu, Rong; Gao, Qian; Zhang, Yan-zhong

    2013-09-01

    Polarization active imager technology obtains images encoded by parameters different than just the reflectivity and therefore provides new information on the image. So polarization active imager systems represent a very powerful observation tool. However, automatic interpretation of the information contained in the reflected intensity of the polarization active image data is extremely difficult because of the speckle phenomenon. An approach for speckle reduction of polarization active image based on the concepts of compressive sensing (CS) theory and edge detection. First, A Canny operator is first utilized to detect and remove edges from the polarization active image. Then, a dictionary learning algorithm which is applied to sparse image representation. The dictionary learning problem is expressed as a box-constrained quadratic program and a fast projected gradient method is introduced to solve it. The Gradient Projection for Square Reconstruction (GPSR) algorithm for solving bound constrained quadratic programming to reduce the speckle noise in the polarization active images. The block-matching 3-D (BM3D) algorithm is used to reduce speckle nosie, it works in two steps: The first one uses hard thresholding to build a relatively clean image for estimating statistics, while the second one performs the actual denoising through empirical Wiener filtering in the transform domain. Finally, the removed edges are added to the reconstructed image. Experimental results show that the visual quality and evaluation indexes outperform the other methods with no edge preservation. The proposed algorithm effectively realizes both despeckling and edge preservation and reaches the state-of-the-art performance.

  19. Light scattering properties of random media with a structure of laser speckle

    NASA Astrophysics Data System (ADS)

    Okamoto, Takashi; Miyamoto, Masaki; Tanaka, Sou

    2008-11-01

    We study the light scattering properties of random media which have the refractive index distribution of threedimensional (3D) clipped laser speckle structures. To evaluate the performance of the speckle media as random laser cavities, we calculated the energy density and the local quality factor inside the media by means of the 3D finite difference time domain (FDTD) method. It is shown that the random media fabricated with the use of three speckle waves superposed without interference have the scattering strength as large as that of particulate media used conventionally for random laser media. To realize the speckle random media, we employed a technique of holographic lithography and fabricated polymer random media by illuminating photopolymer with one or two speckle waves. The far field scattering pattern of the sample media was measured to estimate the refractive index distribution of the samples. The experimental results suggest that a fibrous index structure, which is characteristic of 3D speckle patterns, is formed inside the sample media.

  20. Intraoral 3D scanner

    NASA Astrophysics Data System (ADS)

    Kühmstedt, Peter; Bräuer-Burchardt, Christian; Munkelt, Christoph; Heinze, Matthias; Palme, Martin; Schmidt, Ingo; Hintersehr, Josef; Notni, Gunther

    2007-09-01

    Here a new set-up of a 3D-scanning system for CAD/CAM in dental industry is proposed. The system is designed for direct scanning of the dental preparations within the mouth. The measuring process is based on phase correlation technique in combination with fast fringe projection in a stereo arrangement. The novelty in the approach is characterized by the following features: A phase correlation between the phase values of the images of two cameras is used for the co-ordinate calculation. This works contrary to the usage of only phase values (phasogrammetry) or classical triangulation (phase values and camera image co-ordinate values) for the determination of the co-ordinates. The main advantage of the method is that the absolute value of the phase at each point does not directly determine the coordinate. Thus errors in the determination of the co-ordinates are prevented. Furthermore, using the epipolar geometry of the stereo-like arrangement the phase unwrapping problem of fringe analysis can be solved. The endoscope like measurement system contains one projection and two camera channels for illumination and observation of the object, respectively. The new system has a measurement field of nearly 25mm × 15mm. The user can measure two or three teeth at one time. So the system can by used for scanning of single tooth up to bridges preparations. In the paper the first realization of the intraoral scanner is described.

  1. 'Diamond' in 3-D

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This 3-D, microscopic imager mosaic of a target area on a rock called 'Diamond Jenness' was taken after NASA's Mars Exploration Rover Opportunity ground into the surface with its rock abrasion tool for a second time.

    Opportunity has bored nearly a dozen holes into the inner walls of 'Endurance Crater.' On sols 177 and 178 (July 23 and July 24, 2004), the rover worked double-duty on Diamond Jenness. Surface debris and the bumpy shape of the rock resulted in a shallow and irregular hole, only about 2 millimeters (0.08 inch) deep. The final depth was not enough to remove all the bumps and leave a neat hole with a smooth floor. This extremely shallow depression was then examined by the rover's alpha particle X-ray spectrometer.

    On Sol 178, Opportunity's 'robotic rodent' dined on Diamond Jenness once again, grinding almost an additional 5 millimeters (about 0.2 inch). The rover then applied its Moessbauer spectrometer to the deepened hole. This double dose of Diamond Jenness enabled the science team to examine the rock at varying layers. Results from those grindings are currently being analyzed.

    The image mosaic is about 6 centimeters (2.4 inches) across.

  2. Prominent rocks - 3D

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Many prominent rocks near the Sagan Memorial Station are featured in this image, taken in stereo by the Imager for Mars Pathfinder (IMP) on Sol 3. 3D glasses are necessary to identify surface detail. Wedge is at lower left; Shark, Half-Dome, and Pumpkin are at center. Flat Top, about four inches high, is at lower right. The horizon in the distance is one to two kilometers away.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is an operating division of the California Institute of Technology (Caltech). The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator.

    Click below to see the left and right views individually. [figure removed for brevity, see original site] Left [figure removed for brevity, see original site] Right

  3. Simulations of 3D LPI's relevant to IFE using the PIC code OSIRIS

    NASA Astrophysics Data System (ADS)

    Tsung, F. S.; Mori, W. B.; Winjum, B. J.

    2014-10-01

    We will study three dimensional effects of laser plasma instabilities, including backward raman scattering, the high frequency hybrid instability, and the two plasmon instability using OSIRIS in 3D Cartesian geometry and cylindrical 2D OSIRIS with azimuthal mode decompositions. With our new capabilities we hope to demonstrate that we are capable of studying single speckle physics relevant to IFE in an efficent manner.

  4. Speckle-Based X-Ray Phase-Contrast and Dark-Field Imaging with a Laboratory Source

    NASA Astrophysics Data System (ADS)

    Zanette, I.; Zhou, T.; Burvall, A.; Lundström, U.; Larsson, D. H.; Zdora, M.; Thibault, P.; Pfeiffer, F.; Hertz, H. M.

    2014-06-01

    We report on the observation and application of near-field speckles with a laboratory x-ray source. The detection of speckles is possible thanks to the enhanced brilliance properties of the used liquid-metal-jet source, and opens the way to a range of new applications in laboratory-based coherent x-ray imaging. Here, we use the speckle pattern for multimodal imaging of demonstrator objects. Moreover, we introduce algorithms for phase and dark-field imaging using speckle tracking, and we show that they yield superior results with respect to existing methods.

  5. Video surveillance with speckle imaging

    DOEpatents

    Carrano, Carmen J.; Brase, James M.

    2007-07-17

    A surveillance system looks through the atmosphere along a horizontal or slant path. Turbulence along the path causes blurring. The blurring is corrected by speckle processing short exposure images recorded with a camera. The exposures are short enough to effectively freeze the atmospheric turbulence. Speckle processing is used to recover a better quality image of the scene.

  6. Vibration Analysis by Speckle Interferometry,

    DTIC Science & Technology

    The vibrational modes of complex systems can be visualized with high sensitivity by laser light speckle interferometry. Electronic speckle pattern...interferometry (ESPI), in contrast to holography, does not use photo-chemical storage media but shows a live image of the vibrational modes created by

  7. 3D Spectroscopy in Astronomy

    NASA Astrophysics Data System (ADS)

    Mediavilla, Evencio; Arribas, Santiago; Roth, Martin; Cepa-Nogué, Jordi; Sánchez, Francisco

    2011-09-01

    Preface; Acknowledgements; 1. Introductory review and technical approaches Martin M. Roth; 2. Observational procedures and data reduction James E. H. Turner; 3. 3D Spectroscopy instrumentation M. A. Bershady; 4. Analysis of 3D data Pierre Ferruit; 5. Science motivation for IFS and galactic studies F. Eisenhauer; 6. Extragalactic studies and future IFS science Luis Colina; 7. Tutorials: how to handle 3D spectroscopy data Sebastian F. Sánchez, Begona García-Lorenzo and Arlette Pécontal-Rousset.

  8. Spherical 3D isotropic wavelets

    NASA Astrophysics Data System (ADS)

    Lanusse, F.; Rassat, A.; Starck, J.-L.

    2012-04-01

    Context. Future cosmological surveys will provide 3D large scale structure maps with large sky coverage, for which a 3D spherical Fourier-Bessel (SFB) analysis in spherical coordinates is natural. Wavelets are particularly well-suited to the analysis and denoising of cosmological data, but a spherical 3D isotropic wavelet transform does not currently exist to analyse spherical 3D data. Aims: The aim of this paper is to present a new formalism for a spherical 3D isotropic wavelet, i.e. one based on the SFB decomposition of a 3D field and accompany the formalism with a public code to perform wavelet transforms. Methods: We describe a new 3D isotropic spherical wavelet decomposition based on the undecimated wavelet transform (UWT) described in Starck et al. (2006). We also present a new fast discrete spherical Fourier-Bessel transform (DSFBT) based on both a discrete Bessel transform and the HEALPIX angular pixelisation scheme. We test the 3D wavelet transform and as a toy-application, apply a denoising algorithm in wavelet space to the Virgo large box cosmological simulations and find we can successfully remove noise without much loss to the large scale structure. Results: We have described a new spherical 3D isotropic wavelet transform, ideally suited to analyse and denoise future 3D spherical cosmological surveys, which uses a novel DSFBT. We illustrate its potential use for denoising using a toy model. All the algorithms presented in this paper are available for download as a public code called MRS3D at http://jstarck.free.fr/mrs3d.html

  9. 3D Elevation Program—Virtual USA in 3D

    USGS Publications Warehouse

    Lukas, Vicki; Stoker, J.M.

    2016-04-14

    The U.S. Geological Survey (USGS) 3D Elevation Program (3DEP) uses a laser system called ‘lidar’ (light detection and ranging) to create a virtual reality map of the Nation that is very accurate. 3D maps have many uses with new uses being discovered all the time.  

  10. Methods For Electronic 3-D Moving Pictures Without Glasses

    NASA Astrophysics Data System (ADS)

    Collender, Robert B.

    1987-06-01

    This paper describes implementation approaches in image acquisition and playback for 3-D computer graphics, 3-D television and 3-D theatre movies without special glasses. Projection lamps, spatial light modulators, CRT's and dynamic scanning are all eliminated by the application of an active image array, all static components and a semi-specular screen. The resulting picture shows horizontal parallax with a wide horizontal view field (up to 360 de-grees) giving a holographic appearance in full color with smooth continuous viewing without speckle. Static component systems are compared with dynamic component systems using both linear and circular arrays. Implementation of computer graphic systems are shown that allow complex shaded color images to extend from the viewer's eyes to infinity. Large screen systems visible by hundreds of people are feasible by the use of low f-stops and high gain screens in projection. Screen geometries and special screen properties are shown. Viewing characteristics offer no restrictions in view-position over the entire view-field and have a "look-around" feature for all the categories of computer graphics, television and movies. Standard video cassettes and optical discs can also interface the system to generate a 3-D window viewable without glasses. A prognosis is given for technology application to 3-D pictures without glasses that replicate the daily viewing experience. Super-position of computer graphics on real-world pictures is shown feasible.

  11. Speckle contrast diffuse correlation tomography of complex turbid medium flow

    SciTech Connect

    Huang, Chong; Irwin, Daniel; Lin, Yu; Shang, Yu; He, Lian; Kong, Weikai; Yu, Guoqiang; Luo, Jia

    2015-07-15

    Purpose: Developed herein is a three-dimensional (3D) flow contrast imaging system leveraging advancements in the extension of laser speckle contrast imaging theories to deep tissues along with our recently developed finite-element diffuse correlation tomography (DCT) reconstruction scheme. This technique, termed speckle contrast diffuse correlation tomography (scDCT), enables incorporation of complex optical property heterogeneities and sample boundaries. When combined with a reflectance-based design, this system facilitates a rapid segue into flow contrast imaging of larger, in vivo applications such as humans. Methods: A highly sensitive CCD camera was integrated into a reflectance-based optical system. Four long-coherence laser source positions were coupled to an optical switch for sequencing of tomographic data acquisition providing multiple projections through the sample. This system was investigated through incorporation of liquid and solid tissue-like phantoms exhibiting optical properties and flow characteristics typical of human tissues. Computer simulations were also performed for comparisons. A uniquely encountered smear correction algorithm was employed to correct point-source illumination contributions during image capture with the frame-transfer CCD and reflectance setup. Results: Measurements with scDCT on a homogeneous liquid phantom showed that speckle contrast-based deep flow indices were within 12% of those from standard DCT. Inclusion of a solid phantom submerged below the liquid phantom surface allowed for heterogeneity detection and validation. The heterogeneity was identified successfully by reconstructed 3D flow contrast tomography with scDCT. The heterogeneity center and dimensions and averaged relative flow (within 3%) and localization were in agreement with actuality and computer simulations, respectively. Conclusions: A custom cost-effective CCD-based reflectance 3D flow imaging system demonstrated rapid acquisition of dense boundary

  12. Spacecraft 3D Augmented Reality Mobile App

    NASA Technical Reports Server (NTRS)

    Hussey, Kevin J.; Doronila, Paul R.; Kumanchik, Brian E.; Chan, Evan G.; Ellison, Douglas J.; Boeck, Andrea; Moore, Justin M.

    2013-01-01

    The Spacecraft 3D application allows users to learn about and interact with iconic NASA missions in a new and immersive way using common mobile devices. Using Augmented Reality (AR) techniques to project 3D renditions of the mission spacecraft into real-world surroundings, users can interact with and learn about Curiosity, GRAIL, Cassini, and Voyager. Additional updates on future missions, animations, and information will be ongoing. Using a printed AR Target and camera on a mobile device, users can get up close with these robotic explorers, see how some move, and learn about these engineering feats, which are used to expand knowledge and understanding about space. The software receives input from the mobile device's camera to recognize the presence of an AR marker in the camera's field of view. It then displays a 3D rendition of the selected spacecraft in the user's physical surroundings, on the mobile device's screen, while it tracks the device's movement in relation to the physical position of the spacecraft's 3D image on the AR marker.

  13. What is 3D good for? A review of human performance on stereoscopic 3D displays

    NASA Astrophysics Data System (ADS)

    McIntire, John P.; Havig, Paul R.; Geiselman, Eric E.

    2012-06-01

    This work reviews the human factors-related literature on the task performance implications of stereoscopic 3D displays, in order to point out the specific performance benefits (or lack thereof) one might reasonably expect to observe when utilizing these displays. What exactly is 3D good for? Relative to traditional 2D displays, stereoscopic displays have been shown to enhance performance on a variety of depth-related tasks. These tasks include judging absolute and relative distances, finding and identifying objects (by breaking camouflage and eliciting perceptual "pop-out"), performing spatial manipulations of objects (object positioning, orienting, and tracking), and navigating. More cognitively, stereoscopic displays can improve the spatial understanding of 3D scenes or objects, improve memory/recall of scenes or objects, and improve learning of spatial relationships and environments. However, for tasks that are relatively simple, that do not strictly require depth information for good performance, where other strong cues to depth can be utilized, or for depth tasks that lie outside the effective viewing volume of the display, the purported performance benefits of 3D may be small or altogether absent. Stereoscopic 3D displays come with a host of unique human factors problems including the simulator-sickness-type symptoms of eyestrain, headache, fatigue, disorientation, nausea, and malaise, which appear to effect large numbers of viewers (perhaps as many as 25% to 50% of the general population). Thus, 3D technology should be wielded delicately and applied carefully; and perhaps used only as is necessary to ensure good performance.

  14. Speckle variance OCT imaging of the vasculature in live mammalian embryos

    NASA Astrophysics Data System (ADS)

    Sudheendran, N.; Syed, S. H.; Dickinson, M. E.; Larina, I. V.; Larin, K. V.

    2011-03-01

    Live imaging of normal and abnormal vascular development in mammalian embryos is important tool in embryonic research, which can potentially contribute to understanding, prevention and treatment of cardiovascular birth defects. Here, we used speckle variance analysis of swept source optical coherence tomography (OCT) data sets acquired from live mouse embryos to reconstruct the 3-D structure of the embryonic vasculature. Both Doppler OCT and speckle variance algorithms were used to reconstruct the vascular structure. The results demonstrates that speckle variance imaging provides more accurate representation of the vascular structure, as it is not sensitive to the blood flow direction, while the Doppler OCT imaging misses blood flow component perpendicular to the beam direction. These studies suggest that speckle variance imaging is a promising tool to study vascular development in cultured mouse embryos.

  15. Debris Dispersion Model Using Java 3D

    NASA Technical Reports Server (NTRS)

    Thirumalainambi, Rajkumar; Bardina, Jorge

    2004-01-01

    This paper describes web based simulation of Shuttle launch operations and debris dispersion. Java 3D graphics provides geometric and visual content with suitable mathematical model and behaviors of Shuttle launch. Because the model is so heterogeneous and interrelated with various factors, 3D graphics combined with physical models provides mechanisms to understand the complexity of launch and range operations. The main focus in the modeling and simulation covers orbital dynamics and range safety. Range safety areas include destruct limit lines, telemetry and tracking and population risk near range. If there is an explosion of Shuttle during launch, debris dispersion is explained. The shuttle launch and range operations in this paper are discussed based on the operations from Kennedy Space Center, Florida, USA.

  16. 3D World Building System

    ScienceCinema

    None

    2016-07-12

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  17. 3D Buckligami: Digital Matter

    NASA Astrophysics Data System (ADS)

    van Hecke, Martin; de Reus, Koen; Florijn, Bastiaan; Coulais, Corentin

    2014-03-01

    We present a class of elastic structures which exhibit collective buckling in 3D, and create these by a 3D printing/moulding technique. Our structures consist of cubic lattice of anisotropic unit cells, and we show that their mechanical properties are programmable via the orientation of these unit cells.

  18. 3D World Building System

    SciTech Connect

    2013-10-30

    This video provides an overview of the Sandia National Laboratories developed 3-D World Model Building capability that provides users with an immersive, texture rich 3-D model of their environment in minutes using a laptop and color and depth camera.

  19. LLNL-Earth3D

    SciTech Connect

    2013-10-01

    Earth3D is a computer code designed to allow fast calculation of seismic rays and travel times through a 3D model of the Earth. LLNL is using this for earthquake location and global tomography efforts and such codes are of great interest to the Earth Science community.

  20. Market study: 3-D eyetracker

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A market study of a proposed version of a 3-D eyetracker for initial use at NASA's Ames Research Center was made. The commercialization potential of a simplified, less expensive 3-D eyetracker was ascertained. Primary focus on present and potential users of eyetrackers, as well as present and potential manufacturers has provided an effective means of analyzing the prospects for commercialization.

  1. Euro3D Science Conference

    NASA Astrophysics Data System (ADS)

    Walsh, J. R.

    2004-02-01

    The Euro3D RTN is an EU funded Research Training Network to foster the exploitation of 3D spectroscopy in Europe. 3D spectroscopy is a general term for spectroscopy of an area of the sky and derives its name from its two spatial + one spectral dimensions. There are an increasing number of instruments which use integral field devices to achieve spectroscopy of an area of the sky, either using lens arrays, optical fibres or image slicers, to pack spectra of multiple pixels on the sky (``spaxels'') onto a 2D detector. On account of the large volume of data and the special methods required to reduce and analyse 3D data, there are only a few centres of expertise and these are mostly involved with instrument developments. There is a perceived lack of expertise in 3D spectroscopy spread though the astronomical community and its use in the armoury of the observational astronomer is viewed as being highly specialised. For precisely this reason the Euro3D RTN was proposed to train young researchers in this area and develop user tools to widen the experience with this particular type of data in Europe. The Euro3D RTN is coordinated by Martin M. Roth (Astrophysikalisches Institut Potsdam) and has been running since July 2002. The first Euro3D science conference was held in Cambridge, UK from 22 to 23 May 2003. The main emphasis of the conference was, in keeping with the RTN, to expose the work of the young post-docs who are funded by the RTN. In addition the team members from the eleven European institutes involved in Euro3D also presented instrumental and observational developments. The conference was organized by Andy Bunker and held at the Institute of Astronomy. There were over thirty participants and 26 talks covered the whole range of application of 3D techniques. The science ranged from Galactic planetary nebulae and globular clusters to kinematics of nearby galaxies out to objects at high redshift. Several talks were devoted to reporting recent observations with newly

  2. 3D vision system assessment

    NASA Astrophysics Data System (ADS)

    Pezzaniti, J. Larry; Edmondson, Richard; Vaden, Justin; Hyatt, Bryan; Chenault, David B.; Kingston, David; Geulen, Vanilynmae; Newell, Scott; Pettijohn, Brad

    2009-02-01

    In this paper, we report on the development of a 3D vision system consisting of a flat panel stereoscopic display and auto-converging stereo camera and an assessment of the system's use for robotic driving, manipulation, and surveillance operations. The 3D vision system was integrated onto a Talon Robot and Operator Control Unit (OCU) such that direct comparisons of the performance of a number of test subjects using 2D and 3D vision systems were possible. A number of representative scenarios were developed to determine which tasks benefited most from the added depth perception and to understand when the 3D vision system hindered understanding of the scene. Two tests were conducted at Fort Leonard Wood, MO with noncommissioned officers ranked Staff Sergeant and Sergeant First Class. The scenarios; the test planning, approach and protocols; the data analysis; and the resulting performance assessment of the 3D vision system are reported.

  3. 3D printing in dentistry.

    PubMed

    Dawood, A; Marti Marti, B; Sauret-Jackson, V; Darwood, A

    2015-12-01

    3D printing has been hailed as a disruptive technology which will change manufacturing. Used in aerospace, defence, art and design, 3D printing is becoming a subject of great interest in surgery. The technology has a particular resonance with dentistry, and with advances in 3D imaging and modelling technologies such as cone beam computed tomography and intraoral scanning, and with the relatively long history of the use of CAD CAM technologies in dentistry, it will become of increasing importance. Uses of 3D printing include the production of drill guides for dental implants, the production of physical models for prosthodontics, orthodontics and surgery, the manufacture of dental, craniomaxillofacial and orthopaedic implants, and the fabrication of copings and frameworks for implant and dental restorations. This paper reviews the types of 3D printing technologies available and their various applications in dentistry and in maxillofacial surgery.

  4. PLOT3D user's manual

    NASA Technical Reports Server (NTRS)

    Walatka, Pamela P.; Buning, Pieter G.; Pierce, Larry; Elson, Patricia A.

    1990-01-01

    PLOT3D is a computer graphics program designed to visualize the grids and solutions of computational fluid dynamics. Seventy-four functions are available. Versions are available for many systems. PLOT3D can handle multiple grids with a million or more grid points, and can produce varieties of model renderings, such as wireframe or flat shaded. Output from PLOT3D can be used in animation programs. The first part of this manual is a tutorial that takes the reader, keystroke by keystroke, through a PLOT3D session. The second part of the manual contains reference chapters, including the helpfile, data file formats, advice on changing PLOT3D, and sample command files.

  5. Color speckle in laser displays

    NASA Astrophysics Data System (ADS)

    Kuroda, Kazuo

    2015-07-01

    At the beginning of this century, lighting technology has been shifted from discharge lamps, fluorescent lamps and electric bulbs to solid-state lighting. Current solid-state lighting is based on the light emitting diodes (LED) technology, but the laser lighting technology is developing rapidly, such as, laser cinema projectors, laser TVs, laser head-up displays, laser head mounted displays, and laser headlamps for motor vehicles. One of the main issues of laser displays is the reduction of speckle noise1). For the monochromatic laser light, speckle is random interference pattern on the image plane (retina for human observer). For laser displays, RGB (red-green-blue) lasers form speckle patterns independently, which results in random distribution of chromaticity, called color speckle2).

  6. Astronomical Observations by Speckle Interferometry.

    DTIC Science & Technology

    1986-06-12

    FIELD GROUP IUB-GROUP Speckle Interferometry; Extrasolar Planets; Brown Dwarfs; ,, IAsteroids; Diffraction Limited Imaging; Image Processing...the astrophysi- of T. It is likely that careful visual inspection should cal parameters of r Per which are summarized in Table have detected the...SPECTROSCOPIC BINARIES y Per AND . Cyg 566 TAME V. Residuals to the speckle observations of y Per. TABLE VI. Preliminaq astrophysical parameters for y Per

  7. Walker Ranch 3D seismic images

    SciTech Connect

    Robert J. Mellors

    2016-03-01

    Amplitude images (both vertical and depth slices) extracted from 3D seismic reflection survey over area of Walker Ranch area (adjacent to Raft River). Crossline spacing of 660 feet and inline of 165 feet using a Vibroseis source. Processing included depth migration. Micro-earthquake hypocenters on images. Stratigraphic information and nearby well tracks added to images. Images are embedded in a Microsoft Word document with additional information. Exact location and depth restricted for proprietary reasons. Data collection and processing funded by Agua Caliente. Original data remains property of Agua Caliente.

  8. 3-D Perspective Pasadena, California

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This perspective view shows the western part of the city of Pasadena, California, looking north towards the San Gabriel Mountains. Portions of the cities of Altadena and La Canada, Flintridge are also shown. The image was created from three datasets: the Shuttle Radar Topography Mission (SRTM) supplied the elevation data; Landsat data from November 11, 1986 provided the land surface color (not the sky) and U.S. Geological Survey digital aerial photography provides the image detail. The Rose Bowl, surrounded by a golf course, is the circular feature at the bottom center of the image. The Jet Propulsion Laboratory is the cluster of large buildings north of the Rose Bowl at the base of the mountains. A large landfill, Scholl Canyon, is the smooth area in the lower left corner of the scene. This image shows the power of combining data from different sources to create planning tools to study problems that affect large urban areas. In addition to the well-known earthquake hazards, Southern California is affected by a natural cycle of fire and mudflows. Wildfires strip the mountains of vegetation, increasing the hazards from flooding and mudflows for several years afterwards. Data such as shown on this image can be used to predict both how wildfires will spread over the terrain and also how mudflows will be channeled down the canyons. The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission was designed to collect three dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency

  9. Adaptive-neighborhood speckle removal in multitemporal synthetic aperture radar images.

    PubMed

    Ciuc, M; Bolon, P; Trouve, E; Buzuloiu, V; Rudant, J P

    2001-11-10

    We present a new method for multitemporal synthetic aperture radar image filtering using three-dimensional (3D) adaptive neighborhoods. The method takes both spatial and temporal information into account to derive the speckle-free value of a pixel. For each pixel individually, a 3D adaptive neighborhood is determined that contains only pixels belonging to the same distribution as the current pixel. Then statistics computed inside the established neighborhood are used to derive the filter output. It is shown that the method provides good results by drastically reducing speckle over homogeneous areas while retaining edges and thin structures. The performances of the proposed method are compared in terms of subjective and objective measures with those given by several classical speckle-filtering methods.

  10. Unassisted 3D camera calibration

    NASA Astrophysics Data System (ADS)

    Atanassov, Kalin; Ramachandra, Vikas; Nash, James; Goma, Sergio R.

    2012-03-01

    With the rapid growth of 3D technology, 3D image capture has become a critical part of the 3D feature set on mobile phones. 3D image quality is affected by the scene geometry as well as on-the-device processing. An automatic 3D system usually assumes known camera poses accomplished by factory calibration using a special chart. In real life settings, pose parameters estimated by factory calibration can be negatively impacted by movements of the lens barrel due to shaking, focusing, or camera drop. If any of these factors displaces the optical axes of either or both cameras, vertical disparity might exceed the maximum tolerable margin and the 3D user may experience eye strain or headaches. To make 3D capture more practical, one needs to consider unassisted (on arbitrary scenes) calibration. In this paper, we propose an algorithm that relies on detection and matching of keypoints between left and right images. Frames containing erroneous matches, along with frames with insufficiently rich keypoint constellations, are detected and discarded. Roll, pitch yaw , and scale differences between left and right frames are then estimated. The algorithm performance is evaluated in terms of the remaining vertical disparity as compared to the maximum tolerable vertical disparity.

  11. Ex-vessel neutron dosimetry analysis for westinghouse 4-loop XL pressurized water reactor plant using the RadTrack{sup TM} Code System with the 3D parallel discrete ordinates code RAPTOR-M3G

    SciTech Connect

    Chen, J.; Alpan, F. A.; Fischer, G.A.; Fero, A.H.

    2011-07-01

    Traditional two-dimensional (2D)/one-dimensional (1D) SYNTHESIS methodology has been widely used to calculate fast neutron (>1.0 MeV) fluence exposure to reactor pressure vessel in the belt-line region. However, it is expected that this methodology cannot provide accurate fast neutron fluence calculation at elevations far above or below the active core region. A three-dimensional (3D) parallel discrete ordinates calculation for ex-vessel neutron dosimetry on a Westinghouse 4-Loop XL Pressurized Water Reactor has been done. It shows good agreement between the calculated results and measured results. Furthermore, the results show very different fast neutron flux values at some of the former plate locations and elevations above and below an active core than those calculated by a 2D/1D SYNTHESIS method. This indicates that for certain irregular reactor internal structures, where the fast neutron flux has a very strong local effect, it is required to use a 3D transport method to calculate accurate fast neutron exposure. (authors)

  12. 3D Scan Systems Integration

    DTIC Science & Technology

    2007-11-02

    AGENCY USE ONLY (Leave Blank) 2. REPORT DATE 5 Feb 98 4. TITLE AND SUBTITLE 3D Scan Systems Integration REPORT TYPE AND DATES COVERED...2-89) Prescribed by ANSI Std. Z39-1 298-102 [ EDO QUALITY W3PECTEDI DLA-ARN Final Report for US Defense Logistics Agency on DDFG-T2/P3: 3D...SCAN SYSTEMS INTEGRATION Contract Number SPO100-95-D-1014 Contractor Ohio University Delivery Order # 0001 Delivery Order Title 3D Scan Systems

  13. PLOT3D/AMES, DEC VAX VMS VERSION USING DISSPLA (WITH TURB3D)

    NASA Technical Reports Server (NTRS)

    Buning, P.

    1994-01-01