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1

2D electron temperature diagnostic using soft x-ray imaging technique  

SciTech Connect

We have developed a two-dimensional (2D) electron temperature (T{sub e}) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D T{sub e} image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing T{sub e} image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

Nishimura, K., E-mail: nishim11@nuclear.es.kit.ac.jp; Sanpei, A., E-mail: sanpei@kit.ac.jp; Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S. [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan)] [Department of Electronics, Kyoto Institute of Technology, Kyoto 606-8585 (Japan); Ohdachi, S.; Mizuguchi, N. [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)] [National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292 (Japan)

2014-03-15

2

2D electron temperature diagnostic using soft x-ray imaging technique  

NASA Astrophysics Data System (ADS)

We have developed a two-dimensional (2D) electron temperature (Te) diagnostic system for thermal structure studies in a low-aspect-ratio reversed field pinch (RFP). The system consists of a soft x-ray (SXR) camera with two pin holes for two-kinds of absorber foils, combined with a high-speed camera. Two SXR images with almost the same viewing area are formed through different absorber foils on a single micro-channel plate (MCP). A 2D Te image can then be obtained by calculating the intensity ratio for each element of the images. We have succeeded in distinguishing Te image in quasi-single helicity (QSH) from that in multi-helicity (MH) RFP states, where the former is characterized by concentrated magnetic fluctuation spectrum and the latter, by broad spectrum of edge magnetic fluctuations.

Nishimura, K.; Sanpei, A.; Tanaka, H.; Ishii, G.; Kodera, R.; Ueba, R.; Himura, H.; Masamune, S.; Ohdachi, S.; Mizuguchi, N.

2014-03-01

3

Imaging 2D turbulence  

Microsoft Academic Search

Gravity-driven flow in a soap film tunnel is spatially almost two-dimensional. A modification of particle-image velocimetry\\u000a technique produces a comprehensive quantitative description of the flow. The technique allows simultaneous acquisition of\\u000a the velocity (two components) in the plane of the film and the film thickness. The latter behaves as a scalar advected by\\u000a the flow. The visualization method developed for

P. Vorobieff; M. Rivera; R. E. Ecke

2001-01-01

4

Staring 2-D hadamard transform spectral imager  

DOEpatents

A staring imaging system inputs a 2D spatial image containing multi-frequency spectral information. This image is encoded in one dimension of the image with a cyclic Hadamarid S-matrix. The resulting image is detecting with a spatial 2D detector; and a computer applies a Hadamard transform to recover the encoded image.

Gentry, Stephen M. (Albuquerque, NM); Wehlburg, Christine M. (Albuquerque, NM); Wehlburg, Joseph C. (Albuquerque, NM); Smith, Mark W. (Albuquerque, NM); Smith, Jody L. (Albuquerque, NM)

2006-02-07

5

2D microwave imaging reflectometer electronics.  

PubMed

A 2D microwave imaging reflectometer system has been developed to visualize electron density fluctuations on the DIII-D tokamak. Simultaneously illuminated at four probe frequencies, large aperture optics image reflections from four density-dependent cutoff surfaces in the plasma over an extended region of the DIII-D plasma. Localized density fluctuations in the vicinity of the plasma cutoff surfaces modulate the plasma reflections, yielding a 2D image of electron density fluctuations. Details are presented of the receiver down conversion electronics that generate the in-phase (I) and quadrature (Q) reflectometer signals from which 2D density fluctuation data are obtained. Also presented are details on the control system and backplane used to manage the electronics as well as an introduction to the computer based control program. PMID:25430247

Spear, A G; Domier, C W; Hu, X; Muscatello, C M; Ren, X; Tobias, B J; Luhmann, N C

2014-11-01

6

2-D phase contrast imaging of turbulence structure on LHD  

Microsoft Academic Search

CO2 laser-based phase contrast imaging (PCI) equipped with a 6 by 8 element two-dimensional (2-D) array of photoconductors is used on the large helical device (LHD) for studying plasma density microfluctuations. Observing 2-D structures of turbulence and strong magnetic shear along the viewing line on LHD permit conversion of a 2-D-PCI image to a 2-D picture of the radial distribution

Leonid N. Vyacheslavov; K. Tanaka; A. L. Sanin; K. Kawahata; C. Michael; T. Akiyama

2005-01-01

7

Image Representation Using 2D Gabor Wavelets  

Microsoft Academic Search

This paper extends to two dimensions the frame criterion developed by Daubechies for one-dimensional wavelets, and itcomputes the frame bounds for the particular case of 2D Gabor wavelets. Completeness criteria for 2D Gabor imagerepresentations are important because of their increasing role in many computer vision applications and also in modeling biologicalvision, since recent neurophysiological evidence from the visual cortex of

Tai Sing Lee

1996-01-01

8

Compression of 2-D Biomedical Images 7.1. Introduction  

E-print Network

Chapter 7 Compression of 2-D Biomedical Images 7.1. Introduction On a daily basis, large amounts and Marie BABEL. #12;156 Compression of Biomedical Images and Signals 7.2. Reversible compression of medical Tree Predictive Coding) [ROB 97], #12;Compression of 2-D Biomedical Images 157 - methods based on

Paris-Sud XI, Université de

9

Recovering 3D tumor locations from 2D bioluminescence images  

E-print Network

structure with detailed anatomical structure extracted from high-resolution microCT on a single platform. We imaging modality to BLI is the microCT imaging, which can be used in one session to provide the high extracted from microCT anatomical images. There is a need for 3D reconstruction because 2D BLI images do

Huang, Xiaolei

10

SAR imaging via modern 2-D spectral estimation methods  

Microsoft Academic Search

Discusses the use of modern 2D spectral estimation algorithms for synthetic aperture radar (SAR) imaging. The motivation for applying power spectrum estimation methods to SAR imaging is to improve resolution, remove sidelobe artifacts, and reduce speckle compared to what is possible with conventional Fourier transform SAR imaging techniques. This paper makes two principal contributions to the field of adaptive SAR

Stuart R. Degraaf

1998-01-01

11

Photorealistic image synthesis and camera validation from 2D images  

NASA Astrophysics Data System (ADS)

This paper presents a new 3D scene reconstruction technique using the Unity 3D game engine. The method presented here allow us to reconstruct the shape of simple objects and more complex ones from multiple 2D images, including infrared and digital images from indoor scenes and only digital images from outdoor scenes and then add the reconstructed object to the simulated scene created in Unity 3D, these scenes are then validated with real world scenes. The method used different cameras settings and explores different properties in the reconstructions of the scenes including light, color, texture, shapes and different views. To achieve the highest possible resolution, it was necessary the extraction of partial textures from visible surfaces. To recover the 3D shapes and the depth of simple objects that can be represented by the geometric bodies, there geometric characteristics were used. To estimate the depth of more complex objects the triangulation method was used, for this the intrinsic and extrinsic parameters were calculated using geometric camera calibration. To implement the methods mentioned above the Matlab tool was used. The technique presented here also let's us to simulate small simple videos, by reconstructing a sequence of multiple scenes of the video separated by small margins of time. To measure the quality of the reconstructed images and video scenes the Fast Low Band Model (FLBM) metric from the Video Quality Measurement (VQM) software was used. Low bandwidth perception based features include edges and motion.

Santos Ferrer, Juan C.; González Chévere, David; Manian, Vidya

2014-06-01

12

2D-To-3D Stereoscopic Conversion: Depth-Map Estimation in a 2D Single-View Image  

E-print Network

2D-To-3D Stereoscopic Conversion: Depth-Map Estimation in a 2D Single-View Image Jaeseung Koa to estimate the relative depth map in a single- view image for the 2D-To-3D conversion technique depth map with these two cues and then refine the depth map by post-processing. Finally, a stereoscopic

Kim, Yong Jung

13

Improving 2D mesh image segmentation with Markovian Random Fields  

Microsoft Academic Search

Traditional mesh segmentation methods normally oper- ate on geometrical models with no image information. On the other hand, 2D image-based mesh generation and seg- mentation counterparts, such as Imesh (6) perform the task by following a set of well defined rules derived from the ge- ometry of the triangles, but with no statistical information of the mesh elements. This paper

Alex Jesus Cuadros-vargas; Leandro C. Gerhardinger; Mario De Castro; João Batista Neto; Luis Gustavo Nonato

2006-01-01

14

2D and 3D Elasticity Imaging Using Freehand Ultrasound  

E-print Network

2D and 3D Elasticity Imaging Using Freehand Ultrasound Joel Edward Lindop Pembroke College March. #12;i Summary Medical imaging is vital to modern clinical practice, enabling clinicians to examine to mechanical properties (e.g., stiffness) to which conventional forms of ultrasound, X-ray and magnetic

Drummond, Tom

15

Sparse radar imaging using 2D compressed sensing  

NASA Astrophysics Data System (ADS)

Radar imaging is an ill-posed linear inverse problem and compressed sensing (CS) has been proved to have tremendous potential in this field. This paper surveys the theory of radar imaging and a conclusion is drawn that the processing of ISAR imaging can be denoted mathematically as a problem of 2D sparse decomposition. Based on CS, we propose a novel measuring strategy for ISAR imaging radar and utilize random sub-sampling in both range and azimuth dimensions, which will reduce the amount of sampling data tremendously. In order to handle 2D reconstructing problem, the ordinary solution is converting the 2D problem into 1D by Kronecker product, which will increase the size of dictionary and computational cost sharply. In this paper, we introduce the 2D-SL0 algorithm into the reconstruction of imaging. It is proved that 2D-SL0 can achieve equivalent result as other 1D reconstructing methods, but the computational complexity and memory usage is reduced significantly. Moreover, we will state the results of simulating experiments and prove the effectiveness and feasibility of our method.

Hou, Qingkai; Liu, Yang; Chen, Zengping; Su, Shaoying

2014-10-01

16

2D/3D Image Registration using Regression Learning  

PubMed Central

In computer vision and image analysis, image registration between 2D projections and a 3D image that achieves high accuracy and near real-time computation is challenging. In this paper, we propose a novel method that can rapidly detect an object’s 3D rigid motion or deformation from a 2D projection image or a small set thereof. The method is called CLARET (Correction via Limited-Angle Residues in External Beam Therapy) and consists of two stages: registration preceded by shape space and regression learning. In the registration stage, linear operators are used to iteratively estimate the motion/deformation parameters based on the current intensity residue between the target projec-tion(s) and the digitally reconstructed radiograph(s) (DRRs) of the estimated 3D image. The method determines the linear operators via a two-step learning process. First, it builds a low-order parametric model of the image region’s motion/deformation shape space from its prior 3D images. Second, using learning-time samples produced from the 3D images, it formulates the relationships between the model parameters and the co-varying 2D projection intensity residues by multi-scale linear regressions. The calculated multi-scale regression matrices yield the coarse-to-fine linear operators used in estimating the model parameters from the 2D projection intensity residues in the registration. The method’s application to Image-guided Radiation Therapy (IGRT) requires only a few seconds and yields good results in localizing a tumor under rigid motion in the head and neck and under respiratory deformation in the lung, using one treatment-time imaging 2D projection or a small set thereof. PMID:24058278

Chou, Chen-Rui; Frederick, Brandon; Mageras, Gig; Chang, Sha; Pizer, Stephen

2013-01-01

17

3D Face Reconstruction from 2D Images  

Microsoft Academic Search

This paper surveys the topic of 3D face reconstruction using 2D images from a computer science perspective. Various approaches have been proposed as solutions for this problem but most have their limitations and drawbacks. Shape from shading, shape from silhouettes, shape from motion and analysis by synthesis using morphable models are currently regarded as the main methods of attaining the

W. N. Widanagamaachchi; A. T. Dharmaratne

2008-01-01

18

Topology-preserving rigid transformation of 2D digital images  

E-print Network

1 Topology-preserving rigid transformation of 2D digital images Phuc Ngo, Nicolas Passat, Yukiko first give some conditions under which Phuc Ngo, Yukiko Kenmochi and Hugues Talbot are with the ESIEE- Paris and the Universit´e Paris-Est, LIGM UMR CNRS 8049, Paris, France ({h.ngo

Boyer, Edmond

19

Geometrical Correlation and Matching of 2d Image Shapes  

NASA Astrophysics Data System (ADS)

The problem of image correspondence measure selection for image comparison and matching is addressed. Many practical applications require image matching "just by shape" with no dependence on the concrete intensity or color values. Most popular technique for image shape comparison utilizes the mutual information measure based on probabilistic reasoning and information theory background. Another approach was proposed by Pytiev (so called "Pytiev morphology") based on geometrical and algebraic reasoning. In this framework images are considered as piecewise-constant 2D functions, tessellation of image frame by the set of non-intersected connected regions determines the "shape" of image and the projection of image onto the shape of other image is determined. Morphological image comparison is performed using the normalized morphological correlation coefficients. These coefficients estimate the closeness of one image to the shape of other image. Such image analysis technique can be characterized as an ""ntensity-to-geometry" matching. This paper generalizes the Pytiev morphological approach for obtaining the pure "geometry-to-geometry" matching techniques. The generalized intensity-geometrical correlation coefficient is proposed including the linear correlation coefficient and the square of Pytiev correlation coefficient as its partial cases. The morphological shape correlation coefficient is proposed based on the statistical averaging of images with the same shape. Centered morphological correlation coefficient is obtained under the condition of intensity centering of averaged images. Two types of symmetric geometrical normalized correlation coefficients are proposed for comparison of shape-tessellations. The technique for correlation and matching of shapes with ordered intensities is proposed with correlation measures invariant to monotonous intensity transformations. The quality of proposed geometrical correlation measures is experimentally estimated in the task of visual (TV) and infrared (IR) image matching. First experimental results demonstrate competitive quality and better computational performance relative to state-of-art mutual information measure.

Vizilter, Y. V.; Zheltov, S. Y.

2012-07-01

20

2D Genus Topology of 21-cm Differential Brightness Temperature During Cosmic Reionization  

NASA Astrophysics Data System (ADS)

A novel method to characterize the topology of the early-universe intergalactic medium during the epoch of cosmic reionization is presented. The 21-cm radiation background from high redshift is analyzed through calculation of the 2-dimensional (2D) genus. The radiative transfer of hydrogen-ionizing photons and ionization-rate equations are calculated in a suite of numerical simulations under various input parameters. The 2D genus is calculated from the mock 21-cm images of high-redshift universe. We construct the 2D genus curve by varying the threshold differential brightness temperature, and compare this to the 2D genus curve of the underlying density field. We find that (1) the 2D genus curve reflects the evolutionary track of cosmic reionization and (2) the 2D genus curve can discriminate between certain reionization scenarios and thus indirectly probe the properties of radiation-sources. Choosing the right beam shape of a radio antenna is found crucial for this analysis. Square Kilometre Array (SKA) is found to be a suitable apparatus for this analysis in terms of sensitivity, even though some deterioration of the data for this purpose is unavoidable under the planned size of the antenna core.

Hong, Sungwook E.; Ahn, Kyungjin; Park, Changbom; Kim, Juhan; Iliev, Ilian T.; Mellema, Garrelt

2014-04-01

21

2D Microwave Imaging Reflectometry (MIR) in KSTAR  

NASA Astrophysics Data System (ADS)

It is commonly believed that the small scale plasma turbulence is a key factor of enhancing the energy transport in magnetically confined plasmas. In order to verify the physical mechanism in KSTAR, turbulence measurement has been improved from a simple one-dimensional system to 2D-measurement to validate various theoretical models of the plasma turbulence. An advanced imaging diagnostic concept for electron density fluctuation measurement, microwave imaging reflectometry (MIR), overcomes the shortcomings of the conventional reflectometry. In this paper, a system description of the KSTAR MIR system, laboratory test results, and verification of the design specification with the known coherent oscillations in the core of the plasmas will be addressed. In addition, turbulence quantities such as cross phase analysis with the poloidal rotation velocity estimation will be presented as a preliminary analysis.

Leem, J.; Lee, W.; Kim, M.; Lee, J. A.; Nam, Y.; Yun, G. S.; Park, H. K.; Kim, Y. G.; Park, H.; Kim, K. W.; Domier, C. W.; Luhmann, N. C.

22

Mesophases in nearly 2D room-temperature ionic liquids.  

PubMed

Computer simulations of (i) a [C(12)mim][Tf(2)N] film of nanometric thickness squeezed at kbar pressure by a piecewise parabolic confining potential reveal a mesoscopic in-plane density and composition modulation reminiscent of mesophases seen in 3D samples of the same room-temperature ionic liquid (RTIL). Near 2D confinement, enforced by a high normal load, as well as relatively long aliphatic chains are strictly required for the mesophase formation, as confirmed by computations for two related systems made of (ii) the same [C(12)mim][Tf(2)N] adsorbed at a neutral solid surface and (iii) a shorter-chain RTIL ([C(4)mim][Tf(2)N]) trapped in the potential well of part i. No in-plane modulation is seen for ii and iii. In case ii, the optimal arrangement of charge and neutral tails is achieved by layering parallel to the surface, while, in case iii, weaker dispersion and packing interactions are unable to bring aliphatic tails together into mesoscopic islands, against overwhelming entropy and Coulomb forces. The onset of in-plane mesophases could greatly affect the properties of long-chain RTILs used as lubricants. PMID:19886615

Manini, N; Cesaratto, M; Del Pópolo, M G; Ballone, P

2009-11-26

23

Semi-Automatic 2D-to-3D Image Conversion Techniques for Touchscreen  

E-print Network

Input 3D Image Output Estimated Depth Map Left View Right View #12;What is Depth Map? The depth map an object is far away from the screen. 2D Color Image Depth Map or Depth image #12;De image based on the structure of the input 2D image, which involve two processes: (1) Depth Estimation

Po, Lai-Man

24

PZT-actuated, 2D optical scanning image acquisition  

NASA Astrophysics Data System (ADS)

An image acquisition utilizing a 2D piezoelectric actuated optical scanner is presented. Fabrication and testing of a micromachined optically transmissive cantilever waveguide that operates in the resonant mode is presented with its application as a micro-optical scanner. The optical waveguide has a smaller cross-sectional area (2 µm × 5 µm) than our previous study (62.5 to 420 mm). The scanner is consisted of a single mode optical fiber (SMF28e) mounted on a X-Y coupled piezoelectric bimorphs operating at the actuators' resonant frequencies of 50 Hz and 128 Hz. The scanner achieves a 3.14 mm vertical and 0.61 mm horizontal tip displacements with a ±10V input.

Gu, Kebin; Lin, Keng-Ren; Wang, Wei-Chih

2014-04-01

25

[Design of the 2D-FFT image reconstruction software based on Matlab].  

PubMed

This paper presents a Matlab's implementation for 2D-FFT image reconstruction algorithm of magnetic resonance imaging, with the universal COM component that Windows system can identify. This allows to segregate the 2D-FFT image reconstruction algorithm from the business magnetic resonance imaging closed system, providing the ability for initial data processing before reconstruction, which would be important for improving the image quality, diagnostic value and image post-processing. PMID:19119652

Xu, Hong-yu; Wang, Hong-zhi

2008-09-01

26

A 2-D imaging heat-flux gauge  

SciTech Connect

This report describes a new leadless two-dimensional imaging optical heat-flux gauge. The gauge is made by depositing arrays of thermorgraphic-phosphor (TP) spots onto the faces of a polymethylpentene is insulator. In the first section of the report, we describe several gauge configurations and their prototype realizations. A satisfactory configuration is an array of right triangles on each face that overlay to form squares when the gauge is viewed normal to the surface. The next section of the report treats the thermal conductivity of TPs. We set up an experiment using a comparative longitudinal heat-flow apparatus to measure the previously unknown thermal conductivity of these materials. The thermal conductivity of one TP, Y{sub 2}O{sub 3}:Eu, is 0.0137 W/cm{center dot}K over the temperature range from about 300 to 360 K. The theories underlying the time response of TP gauges and the imaging characteristics are discussed in the next section. Then we discuss several laboratory experiments to (1) demonstrate that the TP heat-flux gauge can be used in imaging applications; (2) obtain a quantum yield that enumerates what typical optical output signal amplitudes can be obtained from TP heat-flux gauges; and (3) determine whether LANL-designed intensified video cameras have sufficient sensitivity to acquire images from the heat-flux gauges. We obtained positive results from all the measurements. Throughout the text, we note limitations, areas where improvements are needed, and where further research is necessary. 12 refs., 25 figs., 4 tabs.

Noel, B.W.; Borella, H.M. (Los Alamos National Lab., NM (United States)); Beshears, D.L.; Sartory, W.K.; Tobin, K.W.; Williams, R.K. (Oak Ridge National Lab., TN (United States)); Turley, W.D. (EG and G Energy Measurements, Inc., Goleta, CA (United States). Santa Barbara Operations)

1991-07-01

27

A review of 3D/2D registration methods for image-guided interventions.  

PubMed

Registration of pre- and intra-interventional data is one of the key technologies for image-guided radiation therapy, radiosurgery, minimally invasive surgery, endoscopy, and interventional radiology. In this paper, we survey those 3D/2D data registration methods that utilize 3D computer tomography or magnetic resonance images as the pre-interventional data and 2D X-ray projection images as the intra-interventional data. The 3D/2D registration methods are reviewed with respect to image modality, image dimensionality, registration basis, geometric transformation, user interaction, optimization procedure, subject, and object of registration. PMID:20452269

Markelj, P; Tomaževi?, D; Likar, B; Pernuš, F

2012-04-01

28

Radiology Lab 0: Introduction to 2D and 3D Imaging  

NSDL National Science Digital Library

This is a self-directed learning module to introduce students to basic concepts of imaging technology as well as to give students practice going between 2D and 3D imaging using everyday objects.Annotated: true

Shaffer, Kitt

2008-10-02

29

2D label-free imaging of resonant grating biochips in ultraviolet  

E-print Network

2D label-free imaging of resonant grating biochips in ultraviolet K. Bougot-Robin, 1,* , J Polytechnique, 91127 Palaiseau, France *kristelle_robin@yahoo.fr Abstract: 2D images of label-free biochips on a biochip dedicated to UV specific absorption," Bios. Bioelec. 24(6), 1585­1591 (2009). 12. J. L. Reverchon

Paris-Sud XI, Université de

30

A Nonrigid Kernel-Based Framework for 2D-3D Pose Estimation and 2D Image Segmentation  

PubMed Central

In this work, we present a nonrigid approach to jointly solving the tasks of 2D-3D pose estimation and 2D image segmentation. In general, most frameworks that couple both pose estimation and segmentation assume that one has exact knowledge of the 3D object. However, under nonideal conditions, this assumption may be violated if only a general class to which a given shape belongs is given (e.g., cars, boats, or planes). Thus, we propose to solve the 2D-3D pose estimation and 2D image segmentation via nonlinear manifold learning of 3D embedded shapes for a general class of objects or deformations for which one may not be able to associate a skeleton model. Thus, the novelty of our method is threefold: First, we present and derive a gradient flow for the task of nonrigid pose estimation and segmentation. Second, due to the possible nonlinear structures of one’s training set, we evolve the preimage obtained through kernel PCA for the task of shape analysis. Third, we show that the derivation for shape weights is general. This allows us to use various kernels, as well as other statistical learning methodologies, with only minimal changes needing to be made to the overall shape evolution scheme. In contrast with other techniques, we approach the nonrigid problem, which is an infinite-dimensional task, with a finite-dimensional optimization scheme. More importantly, we do not explicitly need to know the interaction between various shapes such as that needed for skeleton models as this is done implicitly through shape learning. We provide experimental results on several challenging pose estimation and segmentation scenarios. PMID:20733218

Sandhu, Romeil; Dambreville, Samuel; Yezzi, Anthony; Tannenbaum, Allen

2013-01-01

31

Reconstructing 3D Human Pose from 2D Image Landmarks  

E-print Network

the configurations spanned in the corpus, ensuring anthropometric plausibility while discouraging impossible that violate anthropometric con- straints such as limb proportions, yet yield a projection in 2D that is plausible. The goal is therefore to develop an activity-independent model while ensuring anthropometric

Sheikh, Yaser Ajmal

32

Modified Watershed Algorithm for Segmentation of 2D Images  

Microsoft Academic Search

With the repaid advancement of computer technology, the use of computer-based technologies is increasing in different fields of life. Image segme ntation is an important problem in different fields of image processing and computer vision. Ima ge segmentation is the process of dividing images according to its characteristic e.g., color and objects present in the images. Different methods are presented

Malik Sikandar; Hayat Khiyal; Aihab Khan; Amna Bibi

33

Finite-temperature three-point function in 2D CFT  

NASA Astrophysics Data System (ADS)

We calculate the finite temperature three-point correlation function for primary fields in a 2D conformal field theory in momentum space. This result has applications to any strongly coupled field theory with a 2D CFT dual, as well as to Kerr/CFT.

Becker, Melanie; Cabrera, Yaniel; Su, Ning

2014-09-01

34

Hydrogen Bond Rearrangements in Water Probed with Temperature-Dependent 2D IR  

E-print Network

We use temperature-dependent two-dimensional infrared spectroscopy (2D IR) of dilute HOD in H2O to investigate hydrogen bond rearrangements in water. The OD stretching frequency is sensitive to its environment, and loss ...

Nicodemus, Rebecca A.

35

Temperature-jump 2D IR spectroscopy to study protein conformational dynamics  

E-print Network

Temperature-jump (T-jump) two-dimensional infrared spectroscopy (2D IR) is developed, characterized, and applied to the study of protein folding and association. In solution, protein conformational changes span a wide range ...

Jones, Kevin C. (Kevin Chapman)

2012-01-01

36

Antenna-coupled microbolometer based uncooled 2D array and camera for 2D real-time terahertz imaging  

NASA Astrophysics Data System (ADS)

CEA-Leti has developed a monolithic large focal plane array bolometric technology optimized for 2D real-time imaging in the terahertz range. Each pixel consists in a silicon microbolometer coupled to specific antennas and a resonant quarter-wavelength cavity. First prototypes of imaging arrays have been designed and manufactured for optimized sensing in the 1-3.5THz range where THz quantum cascade lasers are delivering high optical power. NEP in the order of 1 pW/sqrt(Hz) has been assessed at 2.5 THz. This paper reports the steps of this development, starting from the pixel level, to an array associated monolithically to its CMOS ROIC and finally a stand-alone camera. For each step, modeling, technological prototyping and experimental characterizations are presented.

Simoens, F.; Meilhan, J.; Gidon, S.; Lasfargues, G.; Lalanne Dera, J.; Ouvrier-Buffet, J. L.; Pocas, S.; Rabaud, W.; Guellec, F.; Dupont, B.; Martin, S.; Simon, A. C.

2013-09-01

37

Temperature Dependence of IP3-Mediated Local and Global Ca2D George D. Dickinson  

E-print Network

Temperature Dependence of IP3-Mediated Local and Global Ca2D Signals George D. Dickinson * and Ian of California, Irvine, California ABSTRACT We examined the effect of temperature (12­40 C) on local and global and latencies) were markedly accelerated by increasing temperature. In contrast, the amplitude of global Ca2þ

Parker, Ian

38

Hyperspectral image lossless compression using DSC and 2-D CALIC  

Microsoft Academic Search

In recent few years, DSC (Distributed Source Coding) technology is catched much attentions in remote sensing image compression field,due to its excellent performance and low encoding complexity. In this paper, we propose a DSC-based practical solution for hyperspectral image lossless compression system, which applies the DSC technique using the power channel codes of Low-Density-Parity-Check Accumulated(LDPCA) codes and incorporates an efficient

Xueping Yan; Jiaji Wu

2010-01-01

39

2D Imaging of a Helicon Discharge David D. Blackwell Francis F. Chen  

E-print Network

2D Imaging of a Helicon Discharge David D. Blackwell Francis F. Chen Electrical Engineering and Francis F. Chen Electrical Engineering Department, University of California, Los Angeles, California 90095

Chen, Francis F.

40

An image-based shading pipeline for 2D animation Hedlena Bezerra1  

E-print Network

An image-based shading pipeline for 2D animation Hedlena Bezerra1 Bruno Feij´o1 Luiz Velho2 1 PUC 110 22460-320 Rio de Janeiro, RJ, Brazil lvelho@impa.br Abstract Shading for cel animation based on images is a recent research topic in computer-assisted animation. This paper proposes an image

Paris-Sud XI, Université de

41

Hybrid color image segmentation using 2D histogram clustering and region Olivier Lezoray, Hubert Cardot  

E-print Network

Hybrid color image segmentation using 2D histogram clustering and region merging Olivier Lezoray.Lezoray@info.unicaen.fr, Hubert.Cardot@chgb.unicaen.fr Abstract An hybrid segmentation method for color images is presented space influence is studied. 1. Introduction Color image segmentation refers to the partitionning

Lezoray, Olivier

42

Segmentation of 3D CT Volume Images Using a Single 2D Atlas  

E-print Network

Segmentation of 3D CT Volume Images Using a Single 2D Atlas Feng Ding1 , Wee Kheng Leow1 on the segmentation of complex CT/MR images using the atlas-based approach. Most existing methods use 3D atlases which for the segmentation of brain images. This paper presents a method that can segment multiple slices of an abdominal CT

Leow, Wee Kheng

43

On detecting all saddle points in 2D images  

Microsoft Academic Search

Although spatial critical points (saddle points and extrema--minima and maxima) are mathematically well-defined, it is non-trivial to detect them on an arbitrary discrete grid. Discretising a continuous method as well as a straightfor- ward discrete neighbourhood based method do not guarantee to return all critical points. Although not all image anal- ysis tasks require the right amount ofcritical point in

Arjan Kuijper

2004-01-01

44

3-D Reconstruction From 2-D Radiographic Images and Its Application to Clinical Veterinary Medicine  

NASA Astrophysics Data System (ADS)

3D imaging technique is very important and indispensable in diagnosis. The main stream of the technique is one in which 3D image is reconstructed from a set of slice images, such as X-ray CT and MRI. However, these systems require large space and high costs. On the other hand, a low cost and small size 3D imaging system is needed in clinical veterinary medicine, for example, in the case of diagnosis in X-ray car or pasture area. We propose a novel 3D imaging technique using 2-D X-ray radiographic images. This system can be realized by cheaper system than X-ray CT and enables to get 3D image in X-ray car or portable X-ray equipment. In this paper, a 3D visualization technique from 2-D radiographic images is proposed and several reconstructions are shown. These reconstructions are evaluated by veterinarians.

Hamamoto, Kazuhiko; Sato, Motoyoshi

45

Accurate positioning for head and neck cancer patients using 2D and 3D image guidance.  

PubMed

Our goal is to determine an optimized image-guided setup by comparing setup errors determined by two-dimensional (2D) and three-dimensional (3D) image guidance for head and neck cancer (HNC) patients immobilized by customized thermoplastic masks. Nine patients received weekly imaging sessions, for a total of 54, throughout treatment. Patients were first set up by matching lasers to surface marks (initial) and then translationally corrected using manual registration of orthogonal kilovoltage (kV) radiographs with DRRs (2D-2D) on bony anatomy. A kV cone beam CT (kVCBCT) was acquired and manually registered to the simulation CT using only translations (3D-3D) on the same bony anatomy to determine further translational corrections. After treatment, a second set of kVCBCT was acquired to assess intrafractional motion. Averaged over all sessions, 2D-2D registration led to translational corrections from initial setup of 3.5 ± 2.2 (range 0-8) mm. The addition of 3D-3D registration resulted in only small incremental adjustment (0.8 ± 1.5 mm). We retrospectively calculated patient setup rotation errors using an automatic rigid-body algorithm with 6 degrees of freedom (DoF) on regions of interest (ROI) of in-field bony anatomy (mainly the C2 vertebral body). Small rotations were determined for most of the imaging sessions; however, occasionally rotations > 3° were observed. The calculated intrafractional motion with automatic registration was < 3.5 mm for eight patients, and < 2° for all patients. We conclude that daily manual 2D-2D registration on radiographs reduces positioning errors for mask-immobilized HNC patients in most cases, and is easily implemented. 3D-3D registration adds little improvement over 2D-2D registration without correcting rotational errors. We also conclude that thermoplastic masks are effective for patient immobilization. PMID:21330971

Kang, Hyejoo; Lovelock, Dale M; Yorke, Ellen D; Kriminski, Sergey; Lee, Nancy; Amols, Howard I

2011-01-01

46

Accurate positioning for head and neck cancer patients using 2D and 3D image guidance  

PubMed Central

Our goal is to determine an optimized image-guided setup by comparing setup errors determined by two-dimensional (2D) and three-dimensional (3D) image guidance for head and neck cancer (HNC) patients immobilized by customized thermoplastic masks. Nine patients received weekly imaging sessions, for a total of 54, throughout treatment. Patients were first set up by matching lasers to surface marks (initial) and then translationally corrected using manual registration of orthogonal kilovoltage (kV) radiographs with DRRs (2D-2D) on bony anatomy. A kV cone beam CT (kVCBCT) was acquired and manually registered to the simulation CT using only translations (3D-3D) on the same bony anatomy to determine further translational corrections. After treatment, a second set of kVCBCT was acquired to assess intrafractional motion. Averaged over all sessions, 2D-2D registration led to translational corrections from initial setup of 3.5 ± 2.2 (range 0–8) mm. The addition of 3D-3D registration resulted in only small incremental adjustment (0.8 ± 1.5 mm). We retrospectively calculated patient setup rotation errors using an automatic rigid-body algorithm with 6 degrees of freedom (DoF) on regions of interest (ROI) of in-field bony anatomy (mainly the C2 vertebral body). Small rotations were determined for most of the imaging sessions; however, occasionally rotations > 3° were observed. The calculated intrafractional motion with automatic registration was < 3.5 mm for eight patients, and < 2° for all patients. We conclude that daily manual 2D-2D registration on radiographs reduces positioning errors for mask-immobilized HNC patients in most cases, and is easily implemented. 3D-3D registration adds little improvement over 2D-2D registration without correcting rotational errors. We also conclude that thermoplastic masks are effective for patient immobilization. PMID:21330971

Kang, Hyejoo; Lovelock, Dale M.; Yorke, Ellen D.; Kriminiski, Sergey; Lee, Nancy; Amols, Howard I.

2011-01-01

47

Imaging Excited State Dynamics with 2d Electronic Spectroscopy  

NASA Astrophysics Data System (ADS)

Excited states in the condensed phase have extremely high chemical potentials making them highly reactive and difficult to control. Yet in biology, excited state dynamics operate with exquisite precision driving solar light harvesting in photosynthetic complexes though excitonic transport and photochemistry through non-radiative relaxation to photochemical products. Optimized by evolution, these biological systems display manifestly quantum mechanical behaviors including coherent energy transfer, steering wavepacket trajectories through conical intersections and protection of long-lived quantum coherence. To image the underlying excited state dynamics, we have developed a new spectroscopic method allowing us to capture excitonic structure in real time. Through this method and other ultrafast multidimensional spectroscopies, we have captured coherent dynamics within photosynthetic antenna complexes. The data not only reveal how biological systems operate, but these same spectral signatures can be exploited to create new spectroscopic tools to elucidate the underlying Hamiltonian. New data on the role of the protein in photosynthetic systems indicates that the chromophores mix strongly with some bath modes within the system. The implications of this mixing for excitonic transport will be discussed along with prospects for transferring underlying design principles to synthetic systems.

Engel, Gregory S.

2012-06-01

48

A global optimization strategy for 3D-2D registration of vascular images  

E-print Network

set of sample test points are systematically generated. The values of dissimilarity to the registered, for example, a radiologist relies on 2D projection images (e.g. Digital subtraction Angiogram) to visualize the operation. Often, a preoperative 3D image (e.g. 3DRA) of the vasculature is produced for the radiologist

Chung, Albert C. S.

49

Intensity-Based 2D-3D Spine Image Registration Incorporating One Fiducial Marker  

E-print Network

in the cervical spine where the vertebral structures are small and fragile. We are particularly interestedIntensity-Based 2D-3D Spine Image Registration Incorporating One Fiducial Marker Daniel B spine image data. The use of one fiducial marker substantially improves registration accuracy

Pratt, Vaughan

50

Volume estimation from multiplanar 2D ultrasound images using a remote electromagnetic position and orientation sensor  

Microsoft Academic Search

A system is described for calculating volume from a sequence of multiplanar 2D ultrasound images. Ultrasound images are captured using a video digitising card (Hauppauge Win\\/TV card) installed in a personal computer, and regions of interest transformed into 3D space using position and orientation data obtained from an electromagnetic device (Polhemus, Fastrak). The accuracy of the system was assessed by

S. W. Hughes; T. J. D'Arcy; D. J. Maxwell; W. Chiu; A. Milner; J. E. Saunders; R. J. Sheppard

1996-01-01

51

Multiview Geometry for Texture Mapping 2D Images Onto 3D Range Data  

Microsoft Academic Search

The photorealistic modeling of large-scale scenes, such as urban structures, requires a fusion of range sensing tech- nology and traditional digital photography. This paper presents a system that integrates multiview geometry and automated 3D registration techniques for texture mapping 2D images onto 3D range data. The 3D rangescans and the 2D photographs are respectively used to generate a pair of

Lingyun Liu; Gene Yu; George Wolberg; Siavash Zokai

2006-01-01

52

Information Theoretic Integrated Segmentation and Registration of Dual 2D Portal Images and 3D CT Images  

E-print Network

Abstract Information Theoretic Integrated Segmentation and Registration of Dual 2D Portal Images in order to segment the portal images (the max step) and to estimate the registration parameters (the min in the portal image, the segmented structure, in addition to the gray­scale pixel intensity information, can

Duncan, James S.

53

Problem of twin-image elimination in 2-D computer synthesized hologram  

NASA Astrophysics Data System (ADS)

It is well known that one of the basic functions of security holograms is the maximal complication of their nonauthorized reproduction, in other words - counterfeiting. To solve the problem, concealed images that can be observed only under special conditions are placed into a structure of the hologram. A popular way to place concealed image in Diffractive Optical Variable Device (DOVID) is integration into DOVID's structure of a Concealed Laser-Readable Image (CLRI). Traditionally CLRI is a 2-D Computer-Generated Hologram (2-D CGH), which is a digitized Interference Fringe Data (IFD) structure, computed under the scheme of Fourier-hologram synthesis. Such hologram provides inspection of second level with portable laser reading devices. While it is being read, two (+/- 1 order of diffraction) identical images are formed. In this work a special kind of CGH, which restores image only in one diffractive order or two different images in +1 and -1 orders of diffraction proposed.

Braginets, Eugene; Girnyk, Vladimir; Kostyukevych, Sergey; Soroka, Alexander; Androsyuk, Irina

2007-02-01

54

3D surface reconstruction from multiview photographic images using 2D edge contours  

NASA Astrophysics Data System (ADS)

Most techniques for reconstructing 3D shapes from multi-view 2D photographic images require a large number of images. In this paper, we present a new method for reconstructing 3D surfaces, represented by sets of polygons, using a small number, e.g. 10, of 2D photographic images with full prior knowledge of camera configurations. The method is automatic. Unlike most currently available silhouette-based multiview reconstruction methods, 3D surface points and surfaces are reconstructed directly from 2D edges without costly intermediate voxel reconstruction. The surfaces reconstructed by the proposed method are self-optimized. More surface points and polygons are automatically generated on highly curved parts of a surface. Experiments on computer generated objects and real physical objects were conducted to verify the method. [Figure not available: see fulltext.

Prakoonwit, Simant; Benjamin, Ralph

2012-12-01

55

Nanohole-array-based device for 2D snapshot multispectral imaging.  

PubMed

We present a two-dimensional (2D) snapshot multispectral imager that utilizes the optical transmission characteristics of nanohole arrays (NHAs) in a gold film to resolve a mixture of input colors into multiple spectral bands. The multispectral device consists of blocks of NHAs, wherein each NHA has a unique periodicity that results in transmission resonances and minima in the visible and near-infrared regions. The multispectral device was illuminated over a wide spectral range, and the transmission was spectrally unmixed using a least-squares estimation algorithm. A NHA-based multispectral imaging system was built and tested in both reflection and transmission modes. The NHA-based multispectral imager was capable of extracting 2D multispectral images representative of four independent bands within the spectral range of 662 nm to 832 nm for a variety of targets. The multispectral device can potentially be integrated into a variety of imaging sensor systems. PMID:24005065

Najiminaini, Mohamadreza; Vasefi, Fartash; Kaminska, Bozena; Carson, Jeffrey J L

2013-01-01

56

Flow dependence of 2-D temperature distributions induced in the perfused canine kidney by ultrasound.  

PubMed

The influence of perfusate flow rate on the two-dimensional (2-D) temperature distributions induced by hyperthermia in the canine kidney was evaluated. Localized hyperthermia was induced by ultrasound (frequency 2.040 MHz, transducer diameter 6.7 cm) in the ex-vivo perfused kidney. Temperatures were mapped using shielded copper/constantan thermocouple sensors. The 2-D temperature distribution of the kidney was obtained by pulling these sensors through a planar array of eight stainless-steel trocars inserted along its longitudinal axis. The perfusion system allowed for the control of internal/external organ temperature and type of perfusate, and it simulated vasodilation and vasoconstriction by changing the arterial volume flow rate. The temperature data obtained at flow rates ranging from 0 to 570 ml/min and power levels from 0 to 150 W showed that acoustic power densities in excess of 1.5 W/cm2 were required to maintain therapeutic temperatures in this system. Contour maps for characterizing the 2-D temperature distributions induced in this system were analysed with the introduction of a quantitative measure based on the area within a given isotherm. They show the effects of tissue heterogeneity, flow rate, and non-uniform power deposition. Time constants computed from the exponentially decaying temperatures measured following power off ranged from 5 to 555 s. These findings provide a basis for comparison with temperature measurements being acquired in the in-vivo kidney system. Information acquired from this system may facilitate the process of developing tissue-equivalent dynamic phantoms for ultrasound-induced hyperthermia. The ex-vivo model presented in this paper might be used to study the performance of alternative heating applicators, the effect of haematocrit, blood viscosity, and the use of vasoactive drugs. PMID:1880461

Prionas, S D; Raftery, K A; Edmonds, P D; Constantinou, C E

1991-01-01

57

Parameterising root system growth models using 2D neutron radiography images  

NASA Astrophysics Data System (ADS)

Root architecture is a key factor for plant acquisition of water and nutrients from soil. In particular in view of a second green revolution where the below ground parts of agricultural crops are important, it is essential to characterise and quantify root architecture and its effect on plant resource acquisition. Mathematical models can help to understand the processes occurring in the soil-plant system, they can be used to quantify the effect of root and rhizosphere traits on resource acquisition and the response to environmental conditions. In order to do so, root architectural models are coupled with a model of water and solute transport in soil. However, dynamic root architectural models are difficult to parameterise. Novel imaging techniques such as x-ray computed tomography, neutron radiography and magnetic resonance imaging enable the in situ visualisation of plant root systems. Therefore, these images facilitate the parameterisation of dynamic root architecture models. These imaging techniques are capable of producing 3D or 2D images. Moreover, 2D images are also available in the form of hand drawings or from images of standard cameras. While full 3D imaging tools are still limited in resolutions, 2D techniques are a more accurate and less expensive option for observing roots in their environment. However, analysis of 2D images has additional difficulties compared to the 3D case, because of overlapping roots. We present a novel algorithm for the parameterisation of root system growth models based on 2D images of root system. The algorithm analyses dynamic image data. These are a series of 2D images of the root system at different points in time. Image data has already been adjusted for missing links and artefacts and segmentation was performed by applying a matched filter response. From this time series of binary 2D images, we parameterise the dynamic root architecture model in the following way: First, a morphological skeleton is derived from the binary images by a closing and a thinning step. Then, a weighted graph is produced from this skeleton, where root tips and branch points are the nodes of the graph. For each connecting edge, the pixel coordinates are stored in a list. Finally, a root system growth model is used to determine individual roots within the graph. In this way, the sequential appearance of each sub-branch is maintained. We demonstrate the use of this algorithm to determine parameters for the root system growth model of Leitner et al. (2010). We use 2D radiography images of Lupine plants. Parameters that are gained from the images include the length of the apical and basal zones, the internodal distances, the number of branches per root, the branching angels, the root radii, and the root growth rate. Computed parameter values are means of four replicates, i.e. the means over four root systems grown under the same conditions. The root systems were classified according to their branching order, and average parameter values were determined for each root order. Based on these parameters, the dynamics of root system growth can be recaptured and analysed.

Schnepf, Andrea; Felderer, Bernd; Vontobel, Peter; Leitner, Daniel

2013-04-01

58

Automatic 2D-to-3D image conversion using 3D examples from the internet  

NASA Astrophysics Data System (ADS)

The availability of 3D hardware has so far outpaced the production of 3D content. Although to date many methods have been proposed to convert 2D images to 3D stereopairs, the most successful ones involve human operators and, therefore, are time-consuming and costly, while the fully-automatic ones have not yet achieved the same level of quality. This subpar performance is due to the fact that automatic methods usually rely on assumptions about the captured 3D scene that are often violated in practice. In this paper, we explore a radically different approach inspired by our work on saliency detection in images. Instead of relying on a deterministic scene model for the input 2D image, we propose to "learn" the model from a large dictionary of stereopairs, such as YouTube 3D. Our new approach is built upon a key observation and an assumption. The key observation is that among millions of stereopairs available on-line, there likely exist many stereopairs whose 3D content matches that of the 2D input (query). We assume that two stereopairs whose left images are photometrically similar are likely to have similar disparity fields. Our approach first finds a number of on-line stereopairs whose left image is a close photometric match to the 2D query and then extracts depth information from these stereopairs. Since disparities for the selected stereopairs differ due to differences in underlying image content, level of noise, distortions, etc., we combine them by using the median. We apply the resulting median disparity field to the 2D query to obtain the corresponding right image, while handling occlusions and newly-exposed areas in the usual way. We have applied our method in two scenarios. First, we used YouTube 3D videos in search of the most similar frames. Then, we repeated the experiments on a small, but carefully-selected, dictionary of stereopairs closely matching the query. This, to a degree, emulates the results one would expect from the use of an extremely large 3D repository. While far from perfect, the presented results demonstrate that on-line repositories of 3D content can be used for effective 2D-to-3D image conversion. With the continuously increasing amount of 3D data on-line and with the rapidly growing computing power in the cloud, the proposed framework seems a promising alternative to operator-assisted 2D-to-3D conversion.

Konrad, J.; Brown, G.; Wang, M.; Ishwar, P.; Wu, C.; Mukherjee, D.

2012-03-01

59

Registration of 2D x-ray images to 3D MRI by generating pseudo-CT data  

Microsoft Academic Search

Spatial and soft tissue information provided by magnetic resonance imaging can be very valuable during image-guided procedures, where usually only real-time two-dimensional (2D) x-ray images are available. Registration of 2D x-ray images to three-dimensional (3D) magnetic resonance imaging (MRI) data, acquired prior to the procedure, can provide optimal information to guide the procedure. However, registering x-ray images to MRI data

M. J. van der Bom; J. P. W. Pluim; M. J. Gounis; E. B. van de Kraats; S. M. Sprinkhuizen; J. Timmer; R. Homan; L. W. Bartels

2011-01-01

60

Digital breast tomosynthesis image reconstruction using 2D and 3D total variation minimization  

PubMed Central

Background Digital breast tomosynthesis (DBT) is an emerging imaging modality which produces three-dimensional radiographic images of breast. DBT reconstructs tomographic images from a limited view angle, thus data acquired from DBT is not sufficient enough to reconstruct an exact image. It was proven that a sparse image from a highly undersampled data can be reconstructed via compressed sensing (CS) techniques. This can be done by minimizing the l1 norm of the gradient of the image which can also be defined as total variation (TV) minimization. In tomosynthesis imaging problem, this idea was utilized by minimizing total variation of image reconstructed by algebraic reconstruction technique (ART). Previous studies have largely addressed 2-dimensional (2D) TV minimization and only few of them have mentioned 3-dimensional (3D) TV minimization. However, quantitative analysis of 2D and 3D TV minimization with ART in DBT imaging has not been studied. Methods In this paper two different DBT image reconstruction algorithms with total variation minimization have been developed and a comprehensive quantitative analysis of these two methods and ART has been carried out: The first method is ART?+?TV2D where TV is applied to each slice independently. The other method is ART?+?TV3D in which TV is applied by formulating the minimization problem 3D considering all slices. Results A 3D phantom which roughly simulates a breast tomosynthesis image was designed to evaluate the performance of the methods both quantitatively and qualitatively in the sense of visual assessment, structural similarity (SSIM), root means square error (RMSE) of a specific layer of interest (LOI) and total error values. Both methods show superior results in reducing out-of-focus slice blur compared to ART. Conclusions Computer simulations show that ART + TV3D method substantially enhances the reconstructed image with fewer artifacts and smaller error rates than the other two algorithms under the same configuration and parameters and it provides faster convergence rate. PMID:24172584

2013-01-01

61

Single particle 3D reconstruction for 2D crystal images of membrane proteins.  

PubMed

In cases where ultra-flat cryo-preparations of well-ordered two-dimensional (2D) crystals are available, electron crystallography is a powerful method for the determination of the high-resolution structures of membrane and soluble proteins. However, crystal unbending and Fourier-filtering methods in electron crystallography three-dimensional (3D) image processing are generally limited in their performance for 2D crystals that are badly ordered or non-flat. Here we present a single particle image processing approach, which is implemented as an extension of the 2D crystallographic pipeline realized in the 2dx software package, for the determination of high-resolution 3D structures of membrane proteins. The algorithm presented, addresses the low single-to-noise ratio (SNR) of 2D crystal images by exploiting neighborhood correlation between adjacent proteins in the 2D crystal. Compared with conventional single particle processing for randomly oriented particles, the computational costs are greatly reduced due to the crystal-induced limited search space, which allows a much finer search space compared to classical single particle processing. To reduce the considerable computational costs, our software features a hybrid parallelization scheme for multi-CPU clusters and computer with high-end graphic processing units (GPUs). We successfully apply the new refinement method to the structure of the potassium channel MloK1. The calculated 3D reconstruction shows more structural details and contains less noise than the map obtained by conventional Fourier-filtering based processing of the same 2D crystal images. PMID:24382495

Scherer, Sebastian; Arheit, Marcel; Kowal, Julia; Zeng, Xiangyan; Stahlberg, Henning

2014-03-01

62

Comparison of measured 2D ELMs with synthetic images from BOUT++ simulation in KSTAR  

NASA Astrophysics Data System (ADS)

A detailed study of edge-localized mode (ELM) dynamics in the KSTAR tokamak is performed using a two-dimensional (2D) electron cyclotron emission imaging (ECEI) diagnostic system. Highly coherent mode structures rotating in the poloidal view plane are routinely observed in the inter-ELM pedestal region where the optical thickness for ECE rapidly changes and the interpretation of emission intensity is complicated. To have confidence on the measurements, the observed images are compared with synthetic images of the ELM structure deduced from three-field BOUT++ simulations. The synthetic process considers instrumental effects of the ECEI diagnostic, intrinsic broadening of the ECE and background noise. The synthetic 2D images highly resemble the observed structure, providing confidence that the ELM dynamics can be visualized by ECEI.

Kim, M.; Choi, M. J.; Lee, J.; Yun, G. S.; Lee, W.; Park, H. K.; Domier, C. W.; Luhmann, N. C., Jr.; Xu, X. Q.; the KSTAR Team

2014-09-01

63

2D imaging and 3D sensing data acquisition and mutual registration for painting conservation  

NASA Astrophysics Data System (ADS)

We describe the application of 2D and 3D data acquisition and mutual registration to the conservation of paintings. RGB color image acquisition, IR and UV fluorescence imaging, together with the more recent hyperspectral imaging (32 bands) are among the most useful techniques in this field. They generally are meant to provide information on the painting materials, on the employed techniques and on the object state of conservation. However, only when the various images are perfectly registered on each other and on the 3D model, no ambiguity is possible and safe conclusions may be drawn. We present the integration of 2D and 3D measurements carried out on two different paintings: "Madonna of the Yarnwinder" by Leonardo da Vinci, and "Portrait of Lionello d'Este", by Pisanello, both painted in the XV century.

Fontana, Raffaella; Gambino, Maria Chiara; Greco, Marinella; Marras, Luciano; Pampaloni, Enrico M.; Pelagotti, Anna; Pezzati, Luca; Poggi, Pasquale

2004-12-01

64

2D imaging and 3D sensing data acquisition and mutual registration for painting conservation  

NASA Astrophysics Data System (ADS)

We describe the application of 2D and 3D data acquisition and mutual registration to the conservation of paintings. RGB color image acquisition, IR and UV fluorescence imaging, together with the more recent hyperspectral imaging (32 bands) are among the most useful techniques in this field. They generally are meant to provide information on the painting materials, on the employed techniques and on the object state of conservation. However, only when the various images are perfectly registered on each other and on the 3D model, no ambiguity is possible and safe conclusions may be drawn. We present the integration of 2D and 3D measurements carried out on two different paintings: "Madonna of the Yarnwinder" by Leonardo da Vinci, and "Portrait of Lionello d'Este", by Pisanello, both painted in the XV century.

Fontana, Raffaella; Gambino, Maria Chiara; Greco, Marinella; Marras, Luciano; Pampaloni, Enrico M.; Pelagotti, Anna; Pezzati, Luca; Poggi, Pasquale

2005-01-01

65

3D Shape from Silhouette Points in Registered 2D Images Using Conjugate Gradient Method  

E-print Network

3D Shape from Silhouette Points in Registered 2D Images Using Conjugate Gradient Method Andrzej a number of silhouette points obtained from two or more viewpoints and a parametric model of the shape. Our the silhouette points to 3D to their closest silhouette points on the 3D shape. The solution is found using

Hoff, William A.

66

2D array design based on Fermat spiral for ultrasound imaging.  

PubMed

The main challenge faced by 3D ultrasonic imaging with 2D array transducers is the large number of elements required to achieve an acceptable level of quality in the images. Therefore, the optimisation of the array layout, in order to reduce the number of active elements in the aperture, has been a research topic in the last years. Nowadays, array technology has made viable the production of 2D arrays with larger flexibility on elements size, shape and position, allowing to study other configurations different to the classical matrix organisation, such as circular, archimedes spiral or polygonal layout between others. In this work, the problem of designing an imaging system array with large apertures and a very limited number of active elements (N(e)=128 and N(e)=256) using the Fermat spiral layout has been studied. As summary, a general discussion about the most interesting cases is presented. PMID:19819510

Martínez-Graullera, Oscar; Martín, Carlos J; Godoy, Gregorio; Ullate, Luis G

2010-02-01

67

A wavelet relational fuzzy C-means algorithm for 2D gel image segmentation.  

PubMed

One of the most famous algorithms that appeared in the area of image segmentation is the Fuzzy C-Means (FCM) algorithm. This algorithm has been used in many applications such as data analysis, pattern recognition, and image segmentation. It has the advantages of producing high quality segmentation compared to the other available algorithms. Many modifications have been made to the algorithm to improve its segmentation quality. The proposed segmentation algorithm in this paper is based on the Fuzzy C-Means algorithm adding the relational fuzzy notion and the wavelet transform to it so as to enhance its performance especially in the area of 2D gel images. Both proposed modifications aim to minimize the oversegmentation error incurred by previous algorithms. The experimental results of comparing both the Fuzzy C-Means (FCM) and the Wavelet Fuzzy C-Means (WFCM) to the proposed algorithm on real 2D gel images acquired from human leukemias, HL-60 cell lines, and fetal alcohol syndrome (FAS) demonstrate the improvement achieved by the proposed algorithm in overcoming the segmentation error. In addition, we investigate the effect of denoising on the three algorithms. This investigation proves that denoising the 2D gel image before segmentation can improve (in most of the cases) the quality of the segmentation. PMID:24174990

Rashwan, Shaheera; Faheem, Mohamed Talaat; Sarhan, Amany; Youssef, Bayumy A B

2013-01-01

68

A Wavelet Relational Fuzzy C-Means Algorithm for 2D Gel Image Segmentation  

PubMed Central

One of the most famous algorithms that appeared in the area of image segmentation is the Fuzzy C-Means (FCM) algorithm. This algorithm has been used in many applications such as data analysis, pattern recognition, and image segmentation. It has the advantages of producing high quality segmentation compared to the other available algorithms. Many modifications have been made to the algorithm to improve its segmentation quality. The proposed segmentation algorithm in this paper is based on the Fuzzy C-Means algorithm adding the relational fuzzy notion and the wavelet transform to it so as to enhance its performance especially in the area of 2D gel images. Both proposed modifications aim to minimize the oversegmentation error incurred by previous algorithms. The experimental results of comparing both the Fuzzy C-Means (FCM) and the Wavelet Fuzzy C-Means (WFCM) to the proposed algorithm on real 2D gel images acquired from human leukemias, HL-60 cell lines, and fetal alcohol syndrome (FAS) demonstrate the improvement achieved by the proposed algorithm in overcoming the segmentation error. In addition, we investigate the effect of denoising on the three algorithms. This investigation proves that denoising the 2D gel image before segmentation can improve (in most of the cases) the quality of the segmentation. PMID:24174990

Rashwan, Shaheera; Faheem, Mohamed Talaat; Sarhan, Amany; Youssef, Bayumy A. B.

2013-01-01

69

Comparison of spatiotemporal interpolators for 4D image reconstruction from 2D transesophageal ultrasound  

NASA Astrophysics Data System (ADS)

°For electrophysiology intervention monitoring, we intend to reconstruct 4D ultrasound (US) of structures in the beating heart from 2D transesophageal US by scanplane rotation. The image acquisition is continuous but unsynchronized to the heart rate, which results in a sparsely and irregularly sampled dataset and a spatiotemporal interpolation method is desired. Previously, we showed the potential of normalized convolution (NC) for interpolating such datasets. We explored 4D interpolation by 3 different methods: NC, nearest neighbor (NN), and temporal binning followed by linear interpolation (LTB). The test datasets were derived by slicing three 4D echocardiography datasets at random rotation angles (?, range: 0-180) and random normalized cardiac phase (?, range: 0-1). Four different distributions of rotated 2D images with 600, 900, 1350, and 1800 2D input images were created from all TEE sets. A 2D Gaussian kernel was used for NC and optimal kernel sizes (?? and ??) were found by performing an exhaustive search. The RMS gray value error (RMSE) of the reconstructed images was computed for all interpolation methods. The estimated optimal kernels were in the range of ?? = 3.24 - 3.69°/ ?? = 0.045 - 0.048, ?? = 2.79°/ ?? = 0.031 - 0.038, ?? = 2.34°/ ?? = 0.023 - 0.026, and ?? = 1.89°/ ?? = 0.021 - 0.023 for 600, 900, 1350, and 1800 input images respectively. We showed that NC outperforms NN and LTB. For a small number of input images the advantage of NC is more pronounced.

Haak, Alexander; van Stralen, Marijn; van Burken, Gerard; Klein, Stefan; Pluim, Josien P. W.; de Jong, Nico; van der Steen, Antonius F. W.; Bosch, Johan G.

2012-03-01

70

Fiber Bragg grating sensor interrogator based on 2D imaging system.  

PubMed

We propose and demonstrate a fiber Bragg grating sensor interrogator based on a 2D imaging system using a virtually imaged phased array (VIPA) and infrared camera. There are no moving parts, and the interrogator has good stability and reliability. The absolute wavelength accuracy of the interrogator is better than that of traditional diffraction grating and a 1D-imaging-system-based method, thanks to the VIPA's high spectral resolution and large angular dispersion. The wavelength resolution of the interrogator is about 7 pm, and the spectral range of this interrogator is more than 30 nm. The optimum setup for the best wavelength resolution is analyzed. PMID:25320937

Tan, Zhongwei; Ren, Wenhua; Liu, Zhibo; Feng, Suchun; Chen, Zhiwei

2014-08-10

71

Margin structure and destabilisation processes on the Ecuador margin by 2D quantitative seismic imaging  

NASA Astrophysics Data System (ADS)

We analyse multichannel seismic reflection (MCS) data collected during the SISTEUR cruise (2000) on the Nazca-north Andean convergent plate boundary in order to investigate the tectonic impact of gas hydrates and underthrusted asperities on the slope destabilization and the crustal thinning processes. We use preserved amplitude prestack depth migration method (PSDM) by considering four MCS lines, three perpendicular and one parallel to the margin. In order to get in depth, 2D quantitative image of seismic reflectors, the accuracy of the tomographic model is gradually improved by iterative corrections of the background velocity model. Close to the Carnegie ridge, the 9 km-thick oceanic crust has strong internal reflectors caused by the Galapagos hot spot activity. Through the margin, a seismic sequence composed of three acoustically strong reflectors images the top of the subducted oceanic crust, the inter-plate decollement, and the top of the upper margin. Common Image Gathers (CIG) panels are quite flat and semblance panels are around 1 on these layers. The plate interface is imaged acoustically strong, with discontinuous reflectors dipping landward from the trench, down to a maximum depth of 9-10 km below seafloor. The margin basement has been thinned seaward (less than 2km thick), broken up and uplifted. Seamounts of the Nazca oceanic crust are potential agents for basal erosion and deformation of the upper margin. On two crosscut profiles, the decollement dips seaward and strong deep reflectors beneath the upper margin indicate that a large seamount is in the process of being subducted. Shallower, the gas hydrate stability field, illustrated by bottom simulating reflectors (BSR) on seismic profiles, corresponds to a weakness zone. The triggering mechanisms of the slope failure depend on a combination of several parameters. The main one is probably an increase of the slope angle linked to the subduction of asperities like seamounts. A layer of decreased shear strength at the base of the gas hydrate stability field related to pressure or temperature change is another factor. In our study these two factors are joined.

D'Acremont, E.; Ribodetti, A.; Collot, J.; Sage, F.

2005-12-01

72

Radiometer uncertainty equation research of 2D planar scanning PMMW imaging system  

NASA Astrophysics Data System (ADS)

With advances in millimeter-wave technology, passive millimeter-wave (PMMW) imaging technology has received considerable concerns, and it has established itself in a wide range of military and civil practical applications, such as in the areas of remote sensing, blind landing, precision guidance and security inspection. Both the high transparency of clothing at millimeter wavelengths and the spatial resolution required to generate adequate images combine to make imaging at millimeter wavelengths a natural approach of screening people for concealed contraband detection. And at the same time, the passive operation mode does not present a safety hazard to the person who is under inspection. Based on the description to the design and engineering implementation of a W-band two-dimensional (2D) planar scanning imaging system, a series of scanning methods utilized in PMMW imaging are generally compared and analyzed, followed by a discussion on the operational principle of the mode of 2D planar scanning particularly. Furthermore, it is found that the traditional radiometer uncertainty equation, which is derived from a moving platform, does not hold under this 2D planar scanning mode due to the fact that there is no absolute connection between the scanning rates in horizontal direction and vertical direction. Consequently, an improved radiometer uncertainty equation is carried out in this paper, by means of taking the total time spent on scanning and imaging into consideration, with the purpose of solving the problem mentioned above. In addition, the related factors which affect the quality of radiometric images are further investigated under the improved radiometer uncertainty equation, and ultimately some original results are presented and analyzed to demonstrate the significance and validity of this new methodology.

Hu, Taiyang; Xu, Jianzhong; Xiao, Zelong

2009-07-01

73

High-accuracy 2D digital image correlation measurements using low-cost imaging lenses: implementation of a generalized compensation method  

NASA Astrophysics Data System (ADS)

The ideal pinhole imaging model commonly assumed for an ordinary two-dimensional digital image correlation (2D-DIC) system is neither perfect nor stable because of the existence of small out-of-plane motion of the test sample surface that occurred after loading, small out-of-plane motion of the sensor target due to temperature variation of a camera and unavoidable geometric distortion of an imaging lens. In certain cases, these disadvantages can lead to significant errors in the measured displacements and strains. Although a high-quality bilateral telecentric lens has been strongly recommended to be used in the 2D-DIC system as an essential optical component to achieve high-accuracy measurement, it is not generally applicable due to its fixed field of view, limited depth of focus and high cost. To minimize the errors associated with the imperfectness and instability of a common 2D-DIC system using a low-cost imaging lens, a generalized compensation method using a non-deformable reference sample is proposed in this work. With the proposed method, the displacement of the reference sample rigidly attached behind the test sample is first measured using 2D-DIC, and then it is fitted using a parametric model. The fitted parametric model is then used to correct the displacements of the deformed sample to remove the influences of these unfavorable factors. The validity of the proposed compensation method is first verified using out-of-plane translation, out-of-plane rotation, in-plane translation tests and their combinations. Uniaxial tensile tests of an aluminum specimen were also performed to quantitatively examine the strain accuracy of the proposed compensation method. Experiments show that the proposed compensation method is an easy-to-implement yet effective technique for achieving high-accuracy deformation measurement using an ordinary 2D-DIC system.

Pan, Bing; Yu, Liping; Wu, Dafang

2014-02-01

74

Night vision image fusion for target detection with improved 2D maximum entropy segmentation  

NASA Astrophysics Data System (ADS)

Infrared and LLL image are used for night vision target detection. In allusion to the characteristics of night vision imaging and lack of traditional detection algorithm for segmentation and extraction of targets, we propose a method of infrared and LLL image fusion for target detection with improved 2D maximum entropy segmentation. Firstly, two-dimensional histogram was improved by gray level and maximum gray level in weighted area, weights were selected to calculate the maximum entropy for infrared and LLL image segmentation by using the histogram. Compared with the traditional maximum entropy segmentation, the algorithm had significant effect in target detection, and the functions of background suppression and target extraction. And then, the validity of multi-dimensional characteristics AND operation on the infrared and LLL image feature level fusion for target detection is verified. Experimental results show that detection algorithm has a relatively good effect and application in target detection and multiple targets detection in complex background.

Bai, Lian-fa; Liu, Ying-bin; Yue, Jiang; Zhang, Yi

2013-08-01

75

Mathematical models used in segmentation and fractal methods of 2-D ultrasound images  

NASA Astrophysics Data System (ADS)

Mathematical models are widely used in biomedical computing. The extracted data from images using the mathematical techniques are the "pillar" achieving scientific progress in experimental, clinical, biomedical, and behavioural researches. This article deals with the representation of 2-D images and highlights the mathematical support for the segmentation operation and fractal analysis in ultrasound images. A large number of mathematical techniques are suitable to be applied during the image processing stage. The addressed topics cover the edge-based segmentation, more precisely the gradient-based edge detection and active contour model, and the region-based segmentation namely Otsu method. Another interesting mathematical approach consists of analyzing the images using the Box Counting Method (BCM) to compute the fractal dimension. The results of the paper provide explicit samples performed by various combination of methods.

Moldovanu, Simona; Moraru, Luminita; Bibicu, Dorin

2012-11-01

76

2-D Imaging of Edge Turbulence in NSTX and Alcator C-Mod  

Microsoft Academic Search

High-speed 2-D images of edge turbulence in NSTX and Alcator C-Mod have been made using an ultra-fast CCD camera from Princeton Scientific Instruments, Inc. (PSI-4 camera). This camera views fluctuations in the neutral line emission from He or D gas puffs near the outer midplane where roughly 5 eV < Te < 50 eV. The movies show a variety of

J. L. Lowrance; S. J. Zweben; J. L. Terry; R. J. Maqueda; D. P. Stotler; D. A. D'Ippolito; J. R. Myra; J. Boedo; C. E. Bush; R. Maingi; D. Swain; J. Wilgen; B. Labombard; O. Grulke; S. Kaye; B. Leblanc; H. E. Mynick; N. Pomphrey; V. J. Mastrocola; G. Renda; A. Keesee; N. Nishino

2003-01-01

77

A simple method for quantitative imaging of 2D acoustic fields using refracto-vibrometry  

NASA Astrophysics Data System (ADS)

This paper presents a simple 2D method for rapid time resolved quantitative imaging of acoustic waves using refracto-vibrometry. We present the theoretical background, the experimental method and reconstructions of acoustic reflection and interference. We investigate the applicability of the method, in particular the effect of sound radiator geometry. Finite element and experimental reconstructions of the sound fields are analysed. The spatial limitations and accuracy of the method are presented and discussed.

Malkin, Robert; Todd, Thomas; Robert, Daniel

2014-09-01

78

Mid-IR hyperspectral imaging of laminar flames for 2-D scalar values.  

PubMed

This work presents a new emission-based measurement which permits quantification of two-dimensional scalar distributions in laminar flames. A Michelson-based Fourier-transform spectrometer coupled to a mid-infrared camera (1.5 ?m to 5.5 ?m) obtained 256 × 128pixel hyperspectral flame images at high spectral (??? = 0.75cm(?1)) and spatial (0.52 mm) resolutions. The measurements revealed line and band emission from H2O, CO2, and CO. Measurements were collected from a well-characterized partially-premixed ethylene (C2H4) flame produced on a Hencken burner at equivalence ratios, ?, of 0.8, 0.9, 1.1, and 1.3. After describing the instrument and novel calibration methodology, analysis of the flames is presented. A single-layer, line-by-line radiative transfer model is used to retrieve path-averaged temperature, H2O, CO2 and CO column densities from emission spectra between 2.3 ?m to 5.1 ?m. The radiative transfer model uses line intensities from the latest HITEMP and CDSD-4000 spectroscopic databases. For the ? = 1.1 flame, the spectrally estimated temperature for a single pixel 10 mm above burner center was T = (2318 ± 19)K, and agrees favorably with recently reported laser absorption measurements, T = (2348 ± 115)K, and a NASA CEA equilibrium calculation, T = 2389K. Near the base of the flame, absolute concentrations can be estimated, and H2O, CO2, and CO concentrations of (12.5 ± 1.7) %, (10.1 ± 1.0) %, and (3.8 ± 0.3) %, respectively, compared favorably with the corresponding CEA values of 12.8%, 9.9% and 4.1%. Spectrally-estimated temperatures and concentrations at the other equivalence ratios were in similar agreement with measurements and equilibrium calculations. 2-D temperature and species column density maps underscore the ?-dependent chemical composition of the flames. The reported uncertainties are 95% confidence intervals and include both statistical fit errors and the propagation of systematic calibration errors using a Monte Carlo approach. Systematic errors could warrant a factor of two increase in reported uncertainties. This work helps to establish IFTS as a valuable combustion diagnostic tool. PMID:25321539

Rhoby, Michael R; Blunck, David L; Gross, Kevin C

2014-09-01

79

Utilization of 2D ECEI images for the study of the core instability structures under ECRH  

NASA Astrophysics Data System (ADS)

A wide variety of sawtooth patterns have been observed in the core of plasmas assisted by electron cyclotron resonance heating (ECRH) in a large number of tokamaks. In the KSTAR tokamak, the sawtoothing core under ECRH has been visualized in 2D using an electron cyclotron emission imaging (ECE-I) system. The 2D images revealed a variety of instability structures such as dual cores, triple cores, and crescent shaped structure, which are different from the internal kink mode of the normal sawteeth. For rapid identification of the core structure using 1D ECE signals, the characteristic patterns in the ECE time traces have been explained by the corresponding 2D ECEI images. The statistical analysis for more than 600 discharges using this identification method suggests that the current perturbation due to ECRH inside the q=1 surface may be responsible for the altered core instability structures. A simulation based on linearized two-field reduced MHD model is planned to study the role of localized current perturbations.

Choe, G. H.; Nam, Y.; Yun, G. S.; Lee, J. E.; Choi, M. J.; Park, H. K.; Bierwage, A.; Lee, K. D.

2012-10-01

80

Visualizing 2D Probability Distributions from Satellite Image-Derived Data  

NASA Technical Reports Server (NTRS)

Creating maps of biophysical and geophysical variables using Earth Observing System (EOS) satellite image data is an important component of Earth science. These 2D maps have a single value at every location and standard techniques are used to visualize them. Current tools fall short, however, when it is necessary to describe a distribution of values at each location. Distributions may represent a frequency of occurrence over time, frequency of occurrence from multiple runs of an ensemble forecast or possible values from an uncertainty model. 'Distribution data sets' are described, then a case study is presented to visualize such 2D distributions. Distribution data sets are different from multivariate data sets in the sense that the values are for a single variable instead of multiple variables. Our case study data consists of multiple realizations of percent forest cover, generated using a geostatistical technique that combines ground measurements and satellite imagery to model uncertainty about forest cover. We present several approaches for analyzing and visualizing such data sets. The first is a pixel-wise analysis of the probability density functions for the 2D image while the second is an analysis of features identified within the image. Such pixel-wise and feature-wise views will give Earth scientists a more complete understanding of distribution data sets.

Kao, David; Dungan, Jennifer; Pang, Alex; Biegel, Bryan (Technical Monitor)

2002-01-01

81

Image quality of up-converted 2D video from frame-compatible 3D video  

NASA Astrophysics Data System (ADS)

In the stereoscopic frame-compatible format, the separate high-definition left and high-definition right views are reduced in resolution and packed to fit within the same video frame as a conventional two-dimensional high-definition signal. This format has been suggested for 3DTV since it does not require additional transmission bandwidth and entails only small changes to the existing broadcasting infrastructure. In some instances, the frame-compatible format might be used to deliver both 2D and 3D services, e.g., for over-the-air television services. In those cases, the video quality of the 2D service is bound to decrease since the 2D signal will have to be generated by up-converting one of the two views. In this study, we investigated such loss by measuring the perceptual image quality of 1080i and 720p up-converted video as compared to that of full resolution original 2D video. The video was encoded with either a MPEG-2 or a H.264/AVC codec at different bit rates and presented for viewing with either no polarized glasses (2D viewing mode) or with polarized glasses (3D viewing mode). The results confirmed a loss of video quality of the 2D video up-converted material. The loss due to the sampling processes inherent to the frame-compatible format was rather small for both 1080i and 720p video formats; the loss became more substantial with encoding, particularly for MPEG-2 encoding. The 3D viewing mode provided higher quality ratings, possibly because the visibility of the degradations was reduced.

Speranza, Filippo; Tam, Wa James; Vázquez, Carlos; Renaud, Ronald; Blanchfield, Phil

2011-03-01

82

Image Denoising With 2D Scale-Mixing Complex Wavelet Transforms.  

PubMed

This paper introduces an image denoising procedure based on a 2D scale-mixing complex-valued wavelet transform. Both the minimal (unitary) and redundant (maximum overlap) versions of the transform are used. The covariance structure of white noise in wavelet domain is established. Estimation is performed via empirical Bayesian techniques, including versions that preserve the phase of the complex-valued wavelet coefficients and those that do not. The new procedure exhibits excellent quantitative and visual performance, which is demonstrated by simulation on standard test images. PMID:25312931

Remenyi, Norbert; Nicolis, Orietta; Nason, Guy; Vidakovic, Brani

2014-12-01

83

X-Ray Phase-Contrast Imaging with Three 2D Gratings  

PubMed Central

X-ray imaging is of paramount importance for clinical and preclinical imaging but it is fundamentally restricted by the attenuation-based contrast mechanism, which has remained essentially the same since Roentgen's discovery a century ago. Recently, based on the Talbot effect, groundbreaking work was reported using 1D gratings for X-ray phase-contrast imaging with a hospital-grade X-ray tube instead of a synchrotron or microfocused source. In this paper, we report an extension using 2D gratings that reduces the imaging time and increases the accuracy and robustness of phase retrieval compared to current grating-based phase-contrast techniques. Feasibility is demonstrated via numerical simulation. PMID:18401460

Jiang, Ming; Wyatt, Christopher Lee; Wang, Ge

2008-01-01

84

Translational and rotational temperatures of a 2D vibrated granular gas in microgravity  

E-print Network

We present an experimental study performed on a vibrated granular gas enclosed into a 2D rectangular cell. Experiments are realized in microgravity. High speed video recording and optical tracking allow to obtain the full kinematics (translation and rotation) of the particles. The inelastic parameters are retrieved from the experimental trajectories as well as the translational and rotational velocity distributions. We report that the experimental ratio of translational versus rotational temperature decreases to the density of the medium but increases with the driving velocity of the cell. These experimental results are compared with existing theories and we point out the differences observed. We also present a model which fairly predicts the equilibrium experimental temperatures along the direction of vibration.

Yan Grasselli; Georges Bossis; Romain Morini

2014-03-19

85

Calibration and simulation of ASM2d at different temperatures in a phosphorus removal pilot plant.  

PubMed

In this work, an organic and nutrient removal pilot plant was used to study the temperature influence on phosphorus accumulating organisms. Three experiments were carried out at 13, 20 and 24.5 degrees C, achieving a high phosphorus removal percentage in all cases. The ASM2d model was calibrated at 13 and 20 degrees C and the Arrhenius equation constant was obtained for phosphorus removal processes showing that the temperature influences on the biological phosphorus removal subprocesses in a different degree. The 24.5 degrees C experiment was simulated using the model parameters obtained by means of the Arrhenius equation. The simulation results for the three experiments showed good correspondence with the experimental data, demonstrating that the model and the calibrated parameters were able to predict the pilot plant behaviour. PMID:16889256

García-Usach, F; Ferrer, J; Bouzas, A; Seco, A

2006-01-01

86

Augmented depth perception visualization in 2D/3D image fusion.  

PubMed

2D/3D image fusion applications are widely used in endovascular interventions. Complaints from interventionists about existing state-of-art visualization software are usually related to the strong compromise between 2D and 3D visibility or the lack of depth perception. In this paper, we investigate several concepts enabling improvement of current image fusion visualization found in the operating room. First, a contour enhanced visualization is used to circumvent hidden information in the X-ray image. Second, an occlusion and depth color-coding scheme is considered to improve depth perception. To validate our visualization technique both phantom and clinical data are considered. An evaluation is performed in the form of a questionnaire which included 24 participants: ten clinicians and fourteen non-clinicians. Results indicate that the occlusion correction method provides 100% correctness when determining the true position of an aneurysm in X-ray. Further, when integrating an RGB or RB color-depth encoding in the image fusion both perception and intuitiveness are improved. PMID:25066009

Wang, Jian; Kreiser, Matthias; Wang, Lejing; Navab, Nassir; Fallavollita, Pascal

2014-12-01

87

Visualizing 3D Objects from 2D Cross Sectional Images Displayed "In-Situ" versus "Ex-Situ"  

ERIC Educational Resources Information Center

The present research investigates how mental visualization of a 3D object from 2D cross sectional images is influenced by displacing the images from the source object, as is customary in medical imaging. Three experiments were conducted to assess people's ability to integrate spatial information over a series of cross sectional images in order to…

Wu, Bing; Klatzky, Roberta L.; Stetten, George

2010-01-01

88

Large area selective emitters/absorbers based on 2D tantalum photonic crystals for high-temperature energy applications  

E-print Network

We report highly selective emitters based on high-aspect ratio 2D photonic crystals (PhCs) fabricated on large area (2 inch diameter) polycrystalline tantalum substrates, suitable for high-temperature operation. As an ...

Rinnerbauer, V.

89

2D ultrasound image segmentation using graph cuts and local image features  

Microsoft Academic Search

Ultrasound imaging is a popular imaging modality due to a number of favorable properties of this modality. However, the poor quality of ultrasound images makes them a bad choice for segmentation algorithms. In this paper, we present a semi-automatic algorithm for organ segmentation in ultrasound images, by posing it as an energy minimization problem via appropriate definition of energy terms.

Mehrnaz Zouqi; Jagath Samarabandu

2009-01-01

90

Clinical Assessment of 2D/3D Registration Accuracy in 4 Major Anatomic Sites Using On-Board 2D Kilovoltage Images for 6D Patient Setup.  

PubMed

To provide a comprehensive assessment of patient setup accuracy in 6 degrees of freedom (DOFs) using 2-dimensional/3-dimensional (2D/3D) image registration with on-board 2-dimensional kilovoltage (OB-2DkV) radiographic images, we evaluated cranial, head and neck (HN), and thoracic and abdominal sites under clinical conditions. A fast 2D/3D image registration method using graphics processing unit GPU was modified for registration between OB-2DkV and 3D simulation computed tomography (simCT) images, with 3D/3D registration as the gold standard for 6DOF alignment. In 2D/3D registration, body roll rotation was obtained solely by matching orthogonal OB-2DkV images with a series of digitally reconstructed radiographs (DRRs) from simCT with a small rotational increment along the gantry rotation axis. The window/level adjustments for optimal visualization of the bone in OB-2DkV and DRRs were performed prior to registration. Ideal patient alignment at the isocenter was calculated and used as an initial registration position. In 3D/3D registration, cone-beam CT (CBCT) was aligned to simCT on bony structures using a bone density filter in 6DOF. Included in this retrospective study were 37 patients treated in 55 fractions with frameless stereotactic radiosurgery or stereotactic body radiotherapy for cranial and paraspinal cancer. A cranial phantom was used to serve as a control. In all cases, CBCT images were acquired for patient setup with subsequent OB-2DkV verification. It was found that the accuracy of the 2D/3D registration was 0.0 ± 0.5 mm and 0.1° ± 0.4° in phantom. In patient, it is site dependent due to deformation of the anatomy: 0.2 ± 1.6 mm and -0.4° ± 1.2° on average for each dimension for the cranial site, 0.7 ± 1.6 mm and 0.3° ± 1.3° for HN, 0.7 ± 2.0 mm and -0.7° ± 1.1° for the thorax, and 1.1 ± 2.6 mm and -0.5° ± 1.9° for the abdomen. Anatomical deformation and presence of soft tissue in 2D/3D registration affect the consistency with 3D/3D registration in 6DOF: the discrepancy increases in superior to inferior direction. PMID:25223323

Li, Guang; Yang, T Jonathan; Furtado, Hugo; Birkfellner, Wolfgang; Ballangrud, Ase; Powell, Simon N; Mechalakos, James

2014-09-15

91

Database-guided breast tumor detection and segmentation in 2D ultrasound images  

NASA Astrophysics Data System (ADS)

Ultrasonography is a valuable technique for diagnosing breast cancer. Computer-aided tumor detection and segmentation in ultrasound images can reduce labor cost and streamline clinic workflows. In this paper, we propose a fully automatic system to detect and segment breast tumors in 2D ultrasound images. Our system, based on database-guided techniques, learns the knowledge of breast tumor appearance exemplified by expert annotations. For tumor detection, we train a classifier to discriminate between tumors and their background. For tumor segmentation, we propose a discriminative graph cut approach, where both the data fidelity and compatibility functions are learned discriminatively. The performance of the proposed algorithms is demonstrated on a large set of 347 images, achieving a mean contour-to-contour error of 3.75 pixels with about 4.33 seconds.

Zhang, Jingdan; Zhou, Shaohua K.; Brunke, Shelby; Lowery, Carol; Comaniciu, Dorin

2010-03-01

92

Cardiac cycle phase estimation in 2-D echocardiographic images using an artificial neural network.  

PubMed

This paper proposes a new hybrid approach to estimate the cardiac cycle phases in 2-D echocardiographic images as a first step in cardiac volume estimation. We focused on analyzing the atrial systole and diastole events by using the geometrical position of the mitral valve and a set of three image features. The proposed algorithm is based on a tandem of image processing methods and artificial neural networks as a classifier to robustly extract anatomical information. An original set of image features is proposed and derived to recognize the cardiac phases. The aforementioned approach is performed in two denoising scenarios. In the first scenario, the images are corrupted with Gaussian noise, and in the second one with Rayleigh noise distribution. Our hybrid algorithm does not involve any manual tracing of the boundaries for segmentation process. The algorithm is implemented as computer-aided diagnosis (CADi) software. A dataset of 150 images that include both normal and infarct cardiac pathologies was used. We reported an accuracy of 90 % and a 2 ± 0.3 s in terms of execution time of CADi application in a cardiac cycle estimation task. The main contribution of this paper is to propose this hybrid method and a set of image features that can be helpful for automatic detection applications without any user intervention. The results of the employed methods are qualitatively and quantitatively compared in terms of efficiency for both scenarios. PMID:23247838

Bibicu, Dorin; Moraru, Luminita

2013-05-01

93

Photoacoustic imaging for deep targets in the breast using a multichannel 2D array transducer  

NASA Astrophysics Data System (ADS)

A photoacoustic (PA) imaging system was developed to achieve high sensitivity for the detection and characterization of vascular anomalies in the breast in the mammographic geometry. Signal detection from deep in the breast was achieved by a broadband 2D PVDF planar array that has a round shape with one side trimmed straight to improve fit near the chest wall. This array has 572 active elements and a -6dB bandwidth of 0.6-1.7 MHz. The low frequency enhances imaging depth and increases the size of vascular collections displayed without edge enhancement. The PA signals from all the elements go through low noise preamplifiers in the probe that are very close to the array elements for optimized noise control. Driven by 20 independent on-probe signal processing channels, imaging with both high sensitivity and good speed was achieved. To evaluate the imaging depth and the spatial resolution of this system,2.38mm I.D. artificial vessels embedded deeply in ex vivo breasts harvested from fresh cadavers and a 3mm I.D. tube in breast mimicking phantoms made of pork loin and fat tissues were imaged. Using near-infrared laser light with incident energy density within the ANSI safety limit, imaging depths of up to 49 mm in human breasts and 52 mm in phantoms were achieved. With a high power tunable laser working on multiple wavelengths, this system might contribute to 3D noninvasive imaging of morphological and physiological tissue features throughout the breast.

Xie, Zhixing; Wang, Xueding; Morris, Richard F.; Padilla, Frederic R.; Lecarpentier, Gerald L.; Carson, Paul L.

2011-03-01

94

Determination of instantaneous interventricular septum wall thickness by processing sequential 2D echocardiographic images.  

PubMed

Non-invasive quantitative analysis of the heart walls thickness is a fundamental step in diagnosis and discrimination of heart disease. Thickness measurements in 2D echocardiographic images have many applications in research and clinic for assessing of wall stress, wall thickening and viability parameters. Regarding to interventricular septum wall thickness measurement by conventional manual method is more dependent on sonographer experiment; this encouraged these researchers to develop a semi-automatic computer algorithm in accessing to interventricular septum segments thickness. We proposed and carried out a computerized algorithm for wall thickness measurements in 2D echocardiographic image frames. In this program, wall thickness measurement is based of intensity profile function and adaptive bilateral thresholding operation. For validation, thicknesses of septum base and mid segments were estimated in constituent image frames with use of proposed method and then were compared with conventional manual results at same images of the cardiac cycle by statistical methods. In our sample image frames (240 corresponding segments; with different rang of image quality), a bias of 0.10 and 0.12 mm with SD differences of +/-0.81 and +/-0.72 mm and correlation coefficients of 0.87 and 0.89 were found in base and mid segments, respectively. Interobserver variability using the Computer-Assisted Method (CAM) and Conventional Manual Method (CMM) were 4.0 and 4.7% for the basal and 2.8 and 3.9% for the middle segments. The method introduced in the present study permits precise thickness assessment of base and mid segments of the interventricular septum wall and has high concordance with CMM. PMID:19069517

Moladoust, Hassan; Mokhtari-dizaji, Manijhe; Ojaghi-haghighi, Zahra

2007-02-01

95

Low-temperature studies of a 2D Quantum Heisenberg Antiferromagnet  

NASA Astrophysics Data System (ADS)

A recent inelastic neutron scattering experiment of a 2D Quantum Heisenberg Antiferromagnet (2DQHAF) in an applied field [1] revealed novel features in the energy spectrum but the field was limited to 0.3 HSAT due to the exchange strength (J = 17.5 K) of the material under study. (Quinolinium)2CuBr4.2H2O is known [2] to be a molecular-based version of a strongly 2D QHAF with a significantly smaller exchange strength of 6.2 K and a saturation field of 15 T. We report the low-temperature properties (T 1.8 K) of (Quinolinium)2CuBr4.2H2O and discuss its applicability for further investigations.[4pt] [1] N. Tsyrulin, T. Pardina, R. R. P. Singh et al, Phys. Rev. Lett. 102, 197201: 1-4 (2009).[0pt] [2] R. T. Butcher, M. M. Turnbull, C. P. Landee et al, Inorg. Chem. 49, 427-434 (2010).

Landee, Christopher; Xiao, Fan; Turnbull, Mark; Bartolomé, Juan

2013-03-01

96

2D surface temperature measurement of plasma facing components with modulated active pyrometry  

SciTech Connect

In nuclear fusion devices, such as Tore Supra, the plasma facing components (PFC) are in carbon. Such components are exposed to very high heat flux and the surface temperature measurement is mandatory for the safety of the device and also for efficient plasma scenario development. Besides this measurement is essential to evaluate these heat fluxes for a better knowledge of the physics of plasma-wall interaction, it is also required to monitor the fatigue of PFCs. Infrared system (IR) is used to manage to measure surface temperature in real time. For carbon PFCs, the emissivity is high and known (? ? 0.8), therefore the contribution of the reflected flux from environment and collected by the IR cameras can be neglected. However, the future tokamaks such as WEST and ITER will be equipped with PFCs in metal (W and Be/W, respectively) with low and variable emissivities (? ? 0.1–0.4). Consequently, the reflected flux will contribute significantly in the collected flux by IR camera. The modulated active pyrometry, using a bicolor camera, proposed in this paper allows a 2D surface temperature measurement independently of the reflected fluxes and the emissivity. Experimental results with Tungsten sample are reported and compared with simultaneous measurement performed with classical pyrometry (monochromatic and bichromatic) with and without reflective flux demonstrating the efficiency of this method for surface temperature measurement independently of the reflected flux and the emissivity.

Amiel, S.; Loarer, T.; Pocheau, C.; Roche, H.; Gauthier, E.; Aumeunier, M.-H.; Courtois, X.; Jouve, M.; Balorin, C.; Moncada, V. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Le Niliot, C.; Rigollet, F. [Aix-Marseille Univ, IUSTI, UMR CNRS 7343, F-13453 Marseille (France)

2014-10-15

97

Myocardial Infarct Segmentation and Reconstruction from 2D Late-Gadolinium Enhanced Magnetic Resonance Images  

PubMed Central

In this paper, we propose a convex optimization-based algorithm for segmenting myocardial infarct from clinical 2D late-gadolinium enhanced magnetic resonance (LGE-MR) images. Previously segmented left ventricular (LV) myocardium was used to define a region of interest for the infarct segmentation. The infarct segmentation problem was formulated as a continuous min-cut problem, which was solved using its dual formulation, the continuous max-flow (CMF). Bhattacharyya intensity distribution matching was used as the data term, where the prior intensity distributions were computed based on a training data set LGE-MR images from seven patients. The algorithm was parallelized and implemented in a graphics processing unit for reduced computation time. Three-dimensional (3D) volumes of the infarcts were then reconstructed using an interpolation technique we developed based on logarithm of odds. The algorithm was validated using LGE-MR images from 47 patients (309 slices) by comparing computed 2D segmentations and 3D reconstructions to manually generated ones. In addition, the developed algorithm was compared to several previously reported segmentation techniques. The CMF algorithm outperformed the previously reported methods in terms of Dice similarity coefficient. PMID:25485423

Ukwatta, Eranga; Yuan, Jing; Qiu, Wu; Wu, Katherine C.; Trayanova, Natalia; Vadakkumpadan, Fijoy

2015-01-01

98

Temperature dependence of the rate coefficient for charge exchange of metastable O/+//2D/ with N2. [in atmosphere  

NASA Technical Reports Server (NTRS)

Using a data base of aeronomical parameters measured on board the Atmosphere Explorer-C satellite, temperature dependence of the reaction rate coefficient is deduced for the charge exchange of O(+)(2D) with N2. The results indicate the Explorer values determined over the temperature range from 700 to 1900 K are not in conflict with laboratory measurements made at higher temperatures.

Torr, M. R.; Torr, D. G.

1980-01-01

99

First Ion Temperature Images From TWINS Data  

NASA Astrophysics Data System (ADS)

Ion heating has been correlated with several magnetospheric phenomena, including magnetic reconnection, instabilities, and convection of plasma through different regions of the magnetosphere. Thus, it important to be able to measure ion temperatures throughout the magnetosphere to better understand the physics of these phenomena. Effective ion temperatures based on the charge-exchange cross section-corrected energetic neutral atom (ENA) flux versus energy spectrum can be calculated from TWINS data. Effective ion temperatures calculated from the Medium Energy Neutral Atom (MENA) imager on the IMAGE spacecraft using this technique were shown to have excellent (within ~30%) agreement with in-situ measurements from MPA instruments on LANL geosynchronous spacecraft and GEOTAIL. In order to achieve adequate statistics for reliable ion temperature calculations, we can use either data with significant ENA flux rates, such as during geomagnetic storms, or superpositions of multiple data sets. We present ion temperature images from the few small storms that have occurred so far in the TWINS mission. We will present both 'skymap' images as well as 2-D maps created using an algorithm to project the data along each pixel's line-of-sight to the equatorial plane of the Geocentric Solar Magnetospheric (GSM) coordinate system. During intervals for which data is available from both TWINS I and II, we will compare the locations of interesting features as seen by the two satellites.

Keesee, A. M.; Scime, E.

2009-05-01

100

3D Tumor Shape Reconstruction from 2D Bioluminescence Images and Registration with CT Images  

E-print Network

with detailed anatomical structure extracted from high-resolution micro-CT on a single platform. A complementary imaging modality to BLI is the microCT imaging, which can be used in one session to provide

101

Temperature-Dependent Conformations of a Membrane Supported ‘Zinc Porphyrin Tweezer’ by 2D Fluorescence Spectroscopy  

PubMed Central

We studied the equilibrium conformations of a ‘zinc porphyrin tweezer’ composed of two carboxylphenyl-functionalized zinc tetraphenyl porphyrin subunits connected by a 1,4 butyndiol spacer, which was suspended inside the amphiphilic regions of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) liposomes. By combining phase-modulation two-dimensional fluorescence spectroscopy (2D FS) with linear absorbance and fluorimetry, we determined that the zinc porphyrin tweezer adopts a mixture of ‘folded’ and ‘extended’ conformations in the membrane. By fitting an exciton-coupling model to a series of data sets recorded over a range of temperatures (17 – 85 °C) and at different laser center wavelengths, we determined that the folded form of the tweezer is stabilized by a favorable change in the entropy of the local membrane environment. Our results provide insights toward understanding the balance of thermodynamic factors that govern molecular assembly in membranes. PMID:23480874

Widom, Julia R.; Lee, Wonbae; Perdomo-Ortiz, Alejandro; Rappoport, Dmitrij; Molinski, Tadeusz F.; Aspuru-Guzik, Alán; Marcus, Andrew H.

2013-01-01

102

2D aperture synthesis for Lamb wave imaging using co-arrays  

NASA Astrophysics Data System (ADS)

2D ultrasonic arrays in Lamb wave based SHM systems can operate in the phased array (PA) or synthetic focusing (SF) mode. In the real-time PA approach, multiple electronically delayed signals excite transmitting elements to form the desired wave-front, whereas receiving elements are used to sense scattered waves. Due to that, the PA mode requires multi channeled hardware and multiple excitations at numerous azimuths to scan the inspected region of interest. To the contrary, the SF mode, assumes a single element excitation of subsequent transmitters and off-line processing of the acquired data. In the simplest implementation of the SF technique, a single multiplexed input and output channels are required, which results in significant hardware simplification. Performance of a 2D imaging array depends on many parameters, such as, its topology, number of its transducers and their spacing in terms of wavelength as well as the type of weighting function (apodization). Moreover, it is possible to use sparse arrays, which means that not all array elements are used for transmitting and/ or receiving. In this paper the co-array concept is applied to facilitate the synthesis process of an array's aperture used in the multistatic synthetic focusing approach in Lamb waves-based imaging systems. In the coherent imaging, performed in the transmit/receive mode, the sum co-array is a morphological convolution of the transmit/receive sub-arrays. It can be calculated as the set of sums of the individual elements' locations in the sub-arrays used for imaging. The coarray framework will be presented here using two different array topologies, aID uniform linear array and a cross-shaped array that will result in a square coarray. The approach will be discussed in terms of array patterns and beam patterns of the resulting imaging systems. Both, theoretical and experimental results will be given.

Ambrozinski, Lukasz; Stepinski, Tadeusz; Uhl, Tadeusz

2014-03-01

103

Least Square NUFFT Methods Applied to 2D and 3D Radially Encoded MR Image Reconstruction  

PubMed Central

Radially encoded MR imaging (MRI) has gained increasing attention in applications such as hyperpolarized gas imaging, contrast-enhanced MR angiography, and dynamic imaging, due to its motion insensitivity and improved artifact properties. However, since the technique collects k-space samples nonuniformly, multidimensional (especially 3D) radially sampled MRI image reconstruction is challenging. The balance between reconstruction accuracy and speed becomes critical when a large data set is processed. Kaiser-Bessel gridding reconstruction has been widely used for non-Cartesian reconstruction. The objective of this work is to provide an alternative reconstruction option in high dimensions with on-the-fly kernels calculation. The work develops general multi-dimensional least square nonuniform fast Fourier transform (LS-NUFFT) algorithms and incorporates them into a k-space simulation and image reconstruction framework. The method is then applied to reconstruct the radially encoded k-space, although the method addresses general nonuniformity and is applicable to any non-Cartesian patterns. Performance assessments are made by comparing the LS-NUFFT based method with the conventional Kaiser-Bessel gridding method for 2D and 3D radially encoded computer simulated phantoms and physically scanned phantoms. The results show that the LS-NUFFT reconstruction method has better accuracy-speed efficiency than the Kaiser-Bessel gridding method when the kernel weights are calculated on the fly. The accuracy of the LS-NUFFT method depends on the choice of scaling factor, and it is found that for a particular conventional kernel function, using its corresponding deapodization function as scaling factor and utilizing it into the LS-NUFFT framework has the potential to improve accuracy. When a cosine scaling factor is used, in particular, the LS-NUFFT method is faster than Kaiser-Bessel gridding method because of a quasi closed-form solution. The method is successfully applied to 2D and 3D in vivo studies on small animals. PMID:19174334

Song, Jiayu; Liu, Qing H.; Gewalt, Sally L.; Cofer, Gary; Johnson, G. Allan

2009-01-01

104

2D Thermoluminescence imaging of dielectric surface long term charge memory of plasma surface interaction in DBD discharges  

NASA Astrophysics Data System (ADS)

The charge trapping effect due to the exposure of alumina surfaces to plasma has been studied in a volume dielectric barrier discharge (DBD) in Ar and He noble gases. The long lasting charge trapping of alumina dielectric plates, used as barriers in DBDs, is evidenced by an ex situ thermoluminescence (TL) experiment performed with a standard and a custom two-dimensional (2D)-TL apparatus. The spatial density of trapped surface charges is found to be strongly correlated to the plasma morphology, and the surface spatial memory lasted for several minutes to hours after plasma exposure. In the case of Ar, the plasma channel impact signature on the surface shows a higher equivalent radiation dose with respect to the surface plasma wave and the post-discharge species signature. As a consequence, for the development of discharges, inside the dielectric surface the availability of lower energy trapped electrons is larger in the first region of plasma impact. The reported spatial memory increases the likelihood of the occurrence of plasma filaments in the same position in different runs. In He plasmas, the dielectric barrier shows an almost uniform distribution of trapped charges, meaning that there is no preferred region for the development of the discharge. In all cases a slight asymmetry was shown in the direction of the gas flow. This can be interpreted as being due to the long-living species moving in the direction of the gas flow, corresponding with the TL side experiment on the sample exposed to the plasma afterglow. The maximum values and the integral of the 2D-TL images showed a linear relation with the total charge per ac cycle, corresponding with findings for the TL glow curve. In conclusion, 2D-TL images allow the retrieval of information regarding the plasma surface interaction such as the plasma morphology, trap sites and their activation temperature.

Ambrico, Paolo F.; Ambrico, Marianna; Schiavulli, Luigi; De Benedictis, Santolo

2014-07-01

105

DATA FUSION IN 2D AND 3D IMAGE PROCESSING: AN OVERVIEW Isabelle BLOCH, Henri MA^ITRE  

E-print Network

DATA FUSION IN 2D AND 3D IMAGE PROCESSING: AN OVERVIEW Isabelle BLOCH, Henri MA^ITRE Ecole of the art in image fusion, with an emphasis on the emergence of new techniques, often issued from other the aim of data fusion and its speci city when image informationhas to be combined, with emphasis

106

SNARK09 - a software package for reconstruction of 2D images from 1D projections.  

PubMed

The problem of reconstruction of slices and volumes from 1D and 2D projections has arisen in a large number of scientific fields (including computerized tomography, electron microscopy, X-ray microscopy, radiology, radio astronomy and holography). Many different methods (algorithms) have been suggested for its solution. In this paper we present a software package, SNARK09, for reconstruction of 2D images from their 1D projections. In the area of image reconstruction, researchers often desire to compare two or more reconstruction techniques and assess their relative merits. SNARK09 provides a uniform framework to implement algorithms and evaluate their performance. It has been designed to treat both parallel and divergent projection geometries and can either create test data (with or without noise) for use by reconstruction algorithms or use data collected by another software or a physical device. A number of frequently-used classical reconstruction algorithms are incorporated. The package provides a means for easy incorporation of new algorithms for their testing, comparison and evaluation. It comes with tools for statistical analysis of the results and ten worked examples. PMID:23414602

Klukowska, Joanna; Davidi, Ran; Herman, Gabor T

2013-06-01

107

Constructing a Database from Multiple 2D Images for Camera Pose Estimation and Robot Localization  

NASA Technical Reports Server (NTRS)

The LMDB (Landmark Database) Builder software identifies persistent image features (landmarks) in a scene viewed multiple times and precisely estimates the landmarks 3D world positions. The software receives as input multiple 2D images of approximately the same scene, along with an initial guess of the camera poses for each image, and a table of features matched pair-wise in each frame. LMDB Builder aggregates landmarks across an arbitrarily large collection of frames with matched features. Range data from stereo vision processing can also be passed to improve the initial guess of the 3D point estimates. The LMDB Builder aggregates feature lists across all frames, manages the process to promote selected features to landmarks, and iteratively calculates the 3D landmark positions using the current camera pose estimations (via an optimal ray projection method), and then improves the camera pose estimates using the 3D landmark positions. Finally, it extracts image patches for each landmark from auto-selected key frames and constructs the landmark database. The landmark database can then be used to estimate future camera poses (and therefore localize a robotic vehicle that may be carrying the cameras) by matching current imagery to landmark database image patches and using the known 3D landmark positions to estimate the current pose.

Wolf, Michael; Ansar, Adnan I.; Brennan, Shane; Clouse, Daniel S.; Padgett, Curtis W.

2012-01-01

108

Optimal interlayer hopping and high temperature Bose-Einstein condensation of local pairs in quasi 2D superconductors.  

PubMed

Both FeSe and cuprate superconductors are quasi 2D materials with high transition temperatures and local fermion pairs. Motivated by such systems, we investigate real space pairing of fermions in an anisotropic lattice model with intersite attraction, V, and strong local Coulomb repulsion, U, leading to a determination of the optimal conditions for superconductivity from Bose-Einstein condensation. Our aim is to gain insight as to why high temperature superconductors tend to be quasi 2D. We make both analytically and numerically exact solutions for two body local pairing applicable to intermediate and strong V. We find that the Bose-Einstein condensation temperature of such local pairs pairs is maximal when hopping between layers is intermediate relative to in-plane hopping, indicating that the quasi 2D nature of unconventional superconductors has an important contribution to their high transition temperatures. PMID:25629425

Kornilovitch, P E; Hague, J P

2015-02-25

109

Temperature and layer number dependence of the G and 2D phonon energy and damping in graphene.  

PubMed

We have studied the temperature and size dependence of the G and 2D phonon modes in graphene. It is shown that in a graphene monolayer the phonon energy decreases whereas the phonon damping increases with increasing temperature. The electron-phonon interaction leads to hardening whereas the fourth-order anharmonic phonon-phonon processes lead to softening of the phonon energy with increasing temperature. We have shown that the electron-phonon interaction plays an important role also by the dispersion dependence of the phonon G mode, by the observation of the Kohn anomaly. The G mode frequency decreases and damping increases, whereas the 2D phonon frequency and damping increase with increasing layer number. The temperature and size effects of the 2D mode are much stronger than those of the G mode. PMID:22569003

Apostolov, A T; Apostolova, I N; Wesselinowa, J M

2012-06-13

110

2D Seismic Imaging of Elastic Parameters by Frequency Domain Full Waveform Inversion  

NASA Astrophysics Data System (ADS)

Thanks to recent advances in parallel computing, full waveform inversion is today a tractable seismic imaging method to reconstruct physical parameters of the earth interior at different scales ranging from the near- surface to the deep crust. We present a massively parallel 2D frequency-domain full-waveform algorithm for imaging visco-elastic media from multi-component seismic data. The forward problem (i.e. the resolution of the frequency-domain 2D PSV elastodynamics equations) is based on low-order Discontinuous Galerkin (DG) method (P0 and/or P1 interpolations). Thanks to triangular unstructured meshes, the DG method allows accurate modeling of both body waves and surface waves in case of complex topography for a discretization of 10 to 15 cells per shear wavelength. The frequency-domain DG system is solved efficiently for multiple sources with the parallel direct solver MUMPS. The local inversion procedure (i.e. minimization of residuals between observed and computed data) is based on the adjoint-state method which allows to efficiently compute the gradient of the objective function. Applying the inversion hierarchically from the low frequencies to the higher ones defines a multiresolution imaging strategy which helps convergence towards the global minimum. In place of expensive Newton algorithm, the combined use of the diagonal terms of the approximate Hessian matrix and optimization algorithms based on quasi-Newton methods (Conjugate Gradient, LBFGS, ...) allows to improve the convergence of the iterative inversion. The distribution of forward problem solutions over processors driven by a mesh partitioning performed by METIS allows to apply most of the inversion in parallel. We shall present the main features of the parallel modeling/inversion algorithm, assess its scalability and illustrate its performances with realistic synthetic case studies.

Brossier, R.; Virieux, J.; Operto, S.

2008-12-01

111

The concept of 2D gated imaging for particle sizing in a laminar diffusion flame  

NASA Astrophysics Data System (ADS)

In this work, time-resolved laser-induced incandescence (TiRe LII) has been employed to measure primary particle diameters of soot in an atmospheric laminar ethylene diffusion flame. The generated data set complements existing data determined in one single location and takes advantage of the good spatial resolution of the ICCD detection. Time resolution is achieved by shifting the camera gate along the LII decay. One key input parameter for the analysis of time-resolved LII is the local flame temperature. This was determined on a grid throughout the flame by coherent anti-Stokes Raman scattering. The accurate temperature data, in combination with other published data from this flame, are well suited for soot model validation purposes while we showed feasibility of a shifted gate approach to deduce 2D particle sizes in the chosen standard flame.

Hadef, Redjem; Geigle, Klaus Peter; Zerbs, Jochen; Sawchuk, Robert A.; Snelling, David R.

2013-09-01

112

FluoRender: An Application of 2D Image Space Methods for 3D and 4D Confocal Microscopy Data Visualization in Neurobiology Research  

PubMed Central

2D image space methods are processing methods applied after the volumetric data are projected and rendered into the 2D image space, such as 2D filtering, tone mapping and compositing. In the application domain of volume visualization, most 2D image space methods can be carried out more efficiently than their 3D counterparts. Most importantly, 2D image space methods can be used to enhance volume visualization quality when applied together with volume rendering methods. In this paper, we present and discuss the applications of a series of 2D image space methods as enhancements to confocal microscopy visualizations, including 2D tone mapping, 2D compositing, and 2D color mapping. These methods are easily integrated with our existing confocal visualization tool, FluoRender, and the outcome is a full-featured visualization system that meets neurobiologists’ demands for qualitative analysis of confocal microscopy data. PMID:23584131

Wan, Yong; Otsuna, Hideo; Chien, Chi-Bin; Hansen, Charles

2013-01-01

113

Assessment of Prosthesis Alignment after Revision Total Knee Arthroplasty Using EOS 2D and 3D Imaging: A Reliability Study  

PubMed Central

Introduction A new low-dose X-ray device, called EOS, has been introduced for determining lower-limb alignment in 2D and 3D. Reliability has not yet been assessed when using EOS on lower limbs containing a knee prosthesis. Therefore purpose of this study was to determine intraobserver and interobserver reliability of EOS 2D and 3D knee prosthesis alignment measurements after revision total knee arthroplasty (rTKA). Methods Forty anteroposterior and lateral images of 37 rTKA patients were included. Two observers independently performed measurements on these images twice. Varus/valgus angles were measured in 2D (VV2D) and 3D (VV3D). Intraclass correlation coefficients and the Bland and Altman method were used to determine reliability. T-tests were used to test potential differences. Results Intraobserver and interobserver reliability were excellent for VV2D and VV3D. No significant difference or bias between the first and second measurements or the two observers was found. A significant mean and absolute difference of respectively 1.00° and 1.61° existed between 2D and 3D measurements. Conclusions EOS provides reliable varus/valgus measurements in 2D and 3D for the alignment of the knee joint with a knee prosthesis. However, significant differences exist between varus/valgus measurements in 2D and 3D. PMID:25247714

Meijer, Marrigje F.; Boerboom, Alexander L.; Stevens, Martin; Bulstra, Sjoerd K.; Reininga, Inge H. F.

2014-01-01

114

Elemental 2D imaging of paintings with a mobile EDXRF system.  

PubMed

Imaging techniques are now used commonly and intensively in cultural heritage object analysis. Nowadays, many different techniques in nature as well as many applications exist, where they can be applied. X-ray radiography and infrared reflectography as well as UV photography are some of the most applied techniques. The study of works of art usually requires these techniques to be non-invasive. Furthermore, they are frequently required to perform in situ analysis. A few years ago, our laboratory developed a mobile energy-dispersive X-ray fluorescence and UV-vis-NIR coupled spectrometer, especially designed for fieldwork studies, where all three techniques can be applied strictly at the same site of analysis. Recent developments on a new positioning system have now allowed us to perform 2D elemental mappings with our equipment, which is especially well adapted to painting analysis. The system control is carried out entirely through a laptop computer running a dedicated homemade software. The positioning is achieved by means of a CCD camera embedded in the system and controlled via a Wi-Fi connection through the computer. The data acquisition system, which is made through a homemade multichannel pulse height analyzer, being also managed via the software mentioned above, goes through an Ethernet connection. We will present here the new developments of the system and an example of in situ 2D elemental mapping applied on an anonymous oil painting on wood panel. The discovery of a hidden painting under this oil painting makes it a good choice for a first example of 2D large scan with a mobile instrument. PMID:20953768

Hocquet, François-Philippe; Calvo del Castillo, Helena; Cervera Xicotencatl, Ariadna; Bourgeois, Catherine; Oger, Cécile; Marchal, André; Clar, Mathieu; Rakkaa, Saïd; Micha, Edith; Strivay, David

2011-03-01

115

A 2D to 3D ultrasound image registration algorithm for robotically assisted laparoscopic radical prostatectomy  

NASA Astrophysics Data System (ADS)

Robotically assisted laparoscopic radical prostatectomy (RARP) is an effective approach to resect the diseased organ, with stereoscopic views of the targeted tissue improving the dexterity of the surgeons. However, since the laparoscopic view acquires only the surface image of the tissue, the underlying distribution of the cancer within the organ is not observed, making it difficult to make informed decisions on surgical margins and sparing of neurovascular bundles. One option to address this problem is to exploit registration to integrate the laparoscopic view with images of pre-operatively acquired dynamic contrast enhanced (DCE) MRI that can demonstrate the regions of malignant tissue within the prostate. Such a view potentially allows the surgeon to visualize the location of the malignancy with respect to the surrounding neurovascular structures, permitting a tissue-sparing strategy to be formulated directly based on the observed tumour distribution. If the tumour is close to the capsule, it may be determined that the adjacent neurovascular bundle (NVB) needs to be sacrificed within the surgical margin to ensure that any erupted tumour was resected. On the other hand, if the cancer is sufficiently far from the capsule, one or both NVBs may be spared. However, in order to realize such image integration, the pre-operative image needs to be fused with the laparoscopic view of the prostate. During the initial stages of the operation, the prostate must be tracked in real time so that the pre-operative MR image remains aligned with patient coordinate system. In this study, we propose and investigate a novel 2D to 3D ultrasound image registration algorithm to track the prostate motion with an accuracy of 2.68+/-1.31mm.

Esteghamatian, Mehdi; Pautler, Stephen E.; McKenzie, Charles A.; Peters, Terry M.

2011-03-01

116

Investigation of fast particle driven instabilities by 2D electron cyclotron emission imaging on ASDEX Upgrade  

NASA Astrophysics Data System (ADS)

Detailed measurements of the 2D mode structure of Alfvén instabilities in the current ramp-up phase of neutral beam heated discharges were performed on ASDEX Upgrade, using the electron cyclotron emission imaging (ECEI) diagnostic. This paper focuses on the observation of reversed shear Alfvén eigenmodes (RSAEs) and bursting modes that, with the use of the information from ECEI, have been identified as beta-induced Alfvén eigenmodes (BAEs). Both RSAEs with first and second radial harmonic mode structures were observed. Calculations with the linear gyro-kinetic code LIGKA revealed that the ratio of the damping rates and the frequency difference between the first and second harmonic modes strongly depended on the shape of the q-profile. The bursting character of the BAE type modes, which were radially localized to rational q surfaces, was observed to sensitively depend on the plasma parameters, ranging from strongly bursting to almost steady state.

Classen, I. G. J.; Lauber, Ph; Curran, D.; Boom, J. E.; Tobias, B. J.; Domier, C. W.; Luhmann, N. C., Jr.; Park, H. K.; Garcia Munoz, M.; Geiger, B.; Maraschek, M.; Van Zeeland, M. A.; da Graça, S.; ASDEX Upgrade Team

2011-12-01

117

Time-resolved diffusion tomographic 2D and 3D imaging in highly scattering turbid media  

NASA Technical Reports Server (NTRS)

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: ##EQU1## wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine: .LAMBDA..sub.ij =.lambda..sub.j .delta..sub.ij with .lambda..sub.j =/<.DELTA.Xj.DELTA.Xj> Y is the data collected at the detectors, and X.sup.k is the kth iterate toward the desired absoption information. An algorithm, which combines a two dimensional (2D) matrix inversion with a one-dimensional (1D) Fourier transform inversion is used to obtain images of three dimensional hidden objects in turbid scattering media.

Alfano, Robert R. (Inventor); Cai, Wei (Inventor); Liu, Feng (Inventor); Lax, Melvin (Inventor); Das, Bidyut B. (Inventor)

1999-01-01

118

Time-resolved diffusion tomographic 2D and 3D imaging in highly scattering turbid media  

NASA Technical Reports Server (NTRS)

A method for imaging objects in highly scattering turbid media. According to one embodiment of the invention, the method involves using a plurality of intersecting source/detectors sets and time-resolving equipment to generate a plurality of time-resolved intensity curves for the diffusive component of light emergent from the medium. For each of the curves, the intensities at a plurality of times are then inputted into the following inverse reconstruction algorithm to form an image of the medium: wherein W is a matrix relating output at source and detector positions r.sub.s and r.sub.d, at time t, to position r, .LAMBDA. is a regularization matrix, chosen for convenience to be diagonal, but selected in a way related to the ratio of the noise, to fluctuations in the absorption (or diffusion) X.sub.j that we are trying to determine: .LAMBDA..sub.ij =.lambda..sub.j .delta..sub.ij with .lambda..sub.j =/<.DELTA.Xj.DELTA.Xj> Y is the data collected at the detectors, and X.sup.k is the kth iterate toward the desired absorption information. An algorithm, which combines a two dimensional (2D) matrix inversion with a one-dimensional (1D) Fourier transform inversion is used to obtain images of three dimensional hidden objects in turbid scattering media.

Alfano, Robert R. (Inventor); Cai, Wei (Inventor); Gayen, Swapan K. (Inventor)

2000-01-01

119

Web-based interactive 2D/3D medical image processing and visualization software.  

PubMed

There are many medical image processing software tools available for research and diagnosis purposes. However, most of these tools are available only as local applications. This limits the accessibility of the software to a specific machine, and thus the data and processing power of that application are not available to other workstations. Further, there are operating system and processing power limitations which prevent such applications from running on every type of workstation. By developing web-based tools, it is possible for users to access the medical image processing functionalities wherever the internet is available. In this paper, we introduce a pure web-based, interactive, extendable, 2D and 3D medical image processing and visualization application that requires no client installation. Our software uses a four-layered design consisting of an algorithm layer, web-user-interface layer, server communication layer, and wrapper layer. To compete with extendibility of the current local medical image processing software, each layer is highly independent of other layers. A wide range of medical image preprocessing, registration, and segmentation methods are implemented using open source libraries. Desktop-like user interaction is provided by using AJAX technology in the web-user-interface. For the visualization functionality of the software, the VRML standard is used to provide 3D features over the web. Integration of these technologies has allowed implementation of our purely web-based software with high functionality without requiring powerful computational resources in the client side. The user-interface is designed such that the users can select appropriate parameters for practical research and clinical studies. PMID:20022133

Mahmoudi, Seyyed Ehsan; Akhondi-Asl, Alireza; Rahmani, Roohollah; Faghih-Roohi, Shahrooz; Taimouri, Vahid; Sabouri, Ahmad; Soltanian-Zadeh, Hamid

2010-05-01

120

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

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

121

Sparse matrix beamforming and image reconstruction for 2-D HIFU monitoring using harmonic motion imaging for focused ultrasound (HMIFU) with in vitro validation.  

PubMed

Harmonic motion imaging for focused ultrasound (HMIFU) utilizes an amplitude-modulated HIFU beam to induce a localized focal oscillatory motion simultaneously estimated. The objective of this study is to develop and show the feasibility of a novel fast beamforming algorithm for image reconstruction using GPU-based sparse-matrix operation with real-time feedback. In this study, the algorithm was implemented onto a fully integrated, clinically relevant HMIFU system. A single divergent transmit beam was used while fast beamforming was implemented using a GPU-based delay-and-sum method and a sparse-matrix operation. Axial HMI displacements were then estimated from the RF signals using a 1-D normalized cross-correlation method and streamed to a graphic user interface with frame rates up to 15 Hz, a 100-fold increase compared to conventional CPU-based processing. The real-time feedback rate does not require interrupting the HIFU treatment. Results in phantom experiments showed reproducible HMI images and monitoring of 22 in vitro HIFU treatments using the new 2-D system demonstrated reproducible displacement imaging, and monitoring of 22 in vitro HIFU treatments using the new 2-D system showed a consistent average focal displacement decrease of 46.7 ±14.6% during lesion formation. Complementary focal temperature monitoring also indicated an average rate of displacement increase and decrease with focal temperature at 0.84±1.15%/(°)C, and 2.03±0.93%/(°)C , respectively. These results reinforce the HMIFU capability of estimating and monitoring stiffness related changes in real time. Current ongoing studies include clinical translation of the presented system for monitoring of HIFU treatment for breast and pancreatic tumor applications. PMID:24960528

Hou, Gary Y; Provost, Jean; Grondin, Julien; Wang, Shutao; Marquet, Fabrice; Bunting, Ethan; Konofagou, Elisa E

2014-11-01

122

Comparative study of multi-2D, Full 3D and hybrid strategies for multi\\/hyperspectral image compression  

Microsoft Academic Search

In this paper, we investigate appropriate strategies for multi\\/hyperspectral image compression. In particular, we compare the classic multi-2D compression strategy and two different implementations of 3D strategies (Full 3D and hybrid). All strategies are combined with a PCA decorrelation stage to optimize performance. For multi-2D and hybrid strategies, we propose a weighted version of PCA. Finally, for consistent evaluation, we

Jonathan Delcourt; Alamin Mansouri; Tadeusz Sliwa; Yvon Voisin

2009-01-01

123

Temperature-dependent terahertz imaging of excised oral malignant melanoma.  

PubMed

We imaged a single case of oral malignant melanoma using terahertz (THz) reflection imaging at room temperature (20 °C) and below freezing (-20 °C). A malignant nodule beneath the oral tissue surface was visualized using 2-D and B-scan THz imaging techniques. The THz images were well correlated with the histological findings. The nodule was found to have lower water content than that of normal cells, and this water effect may have influenced the THz refractive index and absorption coefficient at 20 °C. The THz spectroscopic image of the frozen tissue at -20 °C showed better contrast because of the lack of liquid water; this implies that there are significant structural differences between malignant oral melanoma cells and normal mucosal cells. The better contrast in the frozen tissue images was due to the greater penetration of THz radiation into the sample. This temperature-dependent THz imaging approach demonstrated the feasibility of accurate imaging of the oral tumor tissue. PMID:25055305

Sim, Yookyeong Carolyn; Ahn, Kang-Min; Park, Jae Yeon; Park, Chan-Sik; Son, Joo-Hiuk

2013-07-01

124

Ultrasound 2D strain estimator based on image registration for ultrasound elastography  

NASA Astrophysics Data System (ADS)

In this paper, we present a new approach to calculate 2D strain through the registration of the pre- and post-compression (deformation) B-mode image sequences based on an intensity-based non-rigid registration algorithm (INRA). Compared with the most commonly used cross-correlation (CC) method, our approach is not constrained to any particular set of directions, and can overcome displacement estimation errors introduced by incoherent motion and variations in the signal under high compression. This INRA method was tested using phantom and in vivo data. The robustness of our approach was demonstrated in the axial direction as well as the lateral direction where the standard CC method frequently fails. In addition, our approach copes well under large compression (over 6%). In the phantom study, we computed the strain image under various compressions and calculated the signal-to-noise (SNR) and contrast-to-noise (CNS) ratios. The SNR and CNS values of the INRA method were much higher than those calculated from the CC-based method. Furthermore, the clinical feasibility of our approach was demonstrated with the in vivo data from patients with arm lymphedema.

Yang, Xiaofeng; Torres, Mylin; Kirkpatrick, Stephanie; Curran, Walter J.; Liu, Tian

2014-03-01

125

2D Iterative Image Reconstruction in Dual Head Micro PET with Lookup System Matrix  

NASA Astrophysics Data System (ADS)

The quality of the reconstructed images in small animal studies through micro PET depends largely on the complexity of the model to determine the system matrix. Each system matrix element corresponds to the probability of the detection of an annihilation event inside the field of view (FOV). Monte Carlo methods allow us to simulate physical process not included in the analytical model, such as non collinearity of gamma rays, positron range effect, interaction of incident gamma rays with the scintillator crystal (including attenuation and Compton scattering effect), etc. We have evaluated the elements of one of the quadrants of the transaxial central plane. The reflection and rotation symmetries have been use to reduce the system matrix calculation time. We use the 2D-Maximum Likelihood Expectation Maximization (MLEM) iterative method with Single Slice Rebinning (SSRB) technique to reconstruct a point source and Derenzo-like phantom images. To evaluate the performance of the Micro PET system, the merit curves and the MOBY mouse phantom reconstruction were obtained.

Ramos, J. M.; Moreno, E. B.; Salazar, H. I.; Martínez, O. B.

2010-12-01

126

Analysis of 2-d ultrasound cardiac strain imaging using joint probability density functions.  

PubMed

Ultrasound frame rates play a key role for accurate cardiac deformation tracking. Insufficient frame rates lead to an increase in signal de-correlation artifacts resulting in erroneous displacement and strain estimation. Joint probability density distributions generated from estimated axial strain and its associated signal-to-noise ratio provide a useful approach to assess the minimum frame rate requirements. Previous reports have demonstrated that bi-modal distributions in the joint probability density indicate inaccurate strain estimation over a cardiac cycle. In this study, we utilize similar analysis to evaluate a 2-D multi-level displacement tracking and strain estimation algorithm for cardiac strain imaging. The effect of different frame rates, final kernel dimensions and a comparison of radio frequency and envelope based processing are evaluated using echo signals derived from a 3-D finite element cardiac model and five healthy volunteers. Cardiac simulation model analysis demonstrates that the minimum frame rates required to obtain accurate joint probability distributions for the signal-to-noise ratio and strain, for a final kernel dimension of 1 ? by 3 A-lines, was around 42 Hz for radio frequency signals. On the other hand, even a frame rate of 250 Hz with envelope signals did not replicate the ideal joint probability distribution. For the volunteer study, clinical data was acquired only at a 34 Hz frame rate, which appears to be sufficient for radio frequency analysis. We also show that an increase in the final kernel dimensions significantly affect the strain probability distribution and joint probability density function generated, with a smaller effect on the variation in the accumulated mean strain estimated over a cardiac cycle. Our results demonstrate that radio frequency frame rates currently achievable on clinical cardiac ultrasound systems are sufficient for accurate analysis of the strain probability distribution, when a multi-level 2-D algorithm and kernel dimensions on the order of 1 ? by 3 A-lines or smaller are utilized. PMID:24613642

Ma, Chi; Varghese, Tomy

2014-06-01

127

Quantitative-phase-contrast imaging of a two-level surface described as a 2D linear filtering process.  

PubMed

The paper deals with quantitative phase imaging of two-height-level surface reliefs. The imaging is considered to be a linear system and, consequently, the Fourier transform of the image is the product of the Fourier transform of a 2D function characterizing the surface and a specific 2D coherent transfer function. The Fourier transform of functions specifying periodic surface reliefs is factorized into two functions similar to lattice and structure amplitudes in crystal structure analysis. The approach to the imaging process described in the paper enables us to examine the dependence of the phase image on the surface geometry. Theoretical results are verified experimentally by means of a digital holographic microscope. PMID:20940953

Lovicar, Lud?k; Komrska, Ji?í; Chmelík, Radim

2010-09-27

128

Application of conformal map theory for design of 2-D ultrasonic array structure for NDT imaging application: a feasibility study.  

PubMed

Two-dimensional ultrasonic phased arrays are becoming increasingly popular in nondestructive evaluation (NDE). Sparse array element configurations are required to fully exploit the potential benefits of 2-D phased arrays. This paper applies the conformal mapping technique as a means of designing sparse 2-D array layouts for NDE applications. Modeling using both Huygens' field prediction theory and 2-D fast Fourier transformation is employed to study the resulting new structure. A conformal power map was used that, for fixed beam width, was shown in simulations to have a greater contrast than rectangular or random arrays. A prototype aperiodic 2-D array configuration for direct contact operation in steel, with operational frequency ~3 MHz, was designed using the array design principle described in this paper. Experimental results demonstrate a working sparse-array transducer capable of performing volumetric imaging. PMID:24569253

Ramadas, Sivaram N; Jackson, Joseph C; Dziewierz, Jerzy; O'Leary, Richard; Gachagan, Anthony

2014-03-01

129

2D harmonic filtering of MR phase images in multicenter clinical setting: Toward a magnetic signature of cerebral microbleeds.  

PubMed

Cerebral microbleeds (CMBs) have emerged as a new imaging marker of small vessel disease. Composed of hemosiderin, CMBs are paramagnetic and can be detected with MRI sequences sensitive to magnetic susceptibility (typically, gradient recalled echo T2* weighted images). Nevertheless, their identification remains challenging on T2* magnitude images because of confounding structures and lesions. In this context, T2* phase image may play a key role in better characterizing CMBs because of its direct relationship with local magnetic field variations due to magnetic susceptibility difference. To address this issue, susceptibility-based imaging techniques were proposed, such as Susceptibility Weighted Imaging (SWI) and Quantitative Susceptibility Mapping (QSM). But these techniques have not yet been validated for 2D clinical data in multicenter settings. Here, we introduce 2DHF, a fast 2D phase processing technique embedding both unwrapping and harmonic filtering designed for data acquired in 2D, even with slice-to-slice inconsistencies. This method results in internal field maps which reveal local field details due to magnetic inhomogeneity within the region of interest only. This technique is based on the physical properties of the induced magnetic field and should yield consistent results. A synthetic phantom was created for numerical simulations. It simulates paramagnetic and diamagnetic lesions within a 'brain-like' tissue, within a background. The method was evaluated on both this synthetic phantom and multicenter 2D datasets acquired in standardized clinical setting, and compared with two state-of-the-art methods. It proved to yield consistent results on synthetic images and to be applicable and robust on patient data. As a proof-of-concept, we finally illustrate that it is possible to find a magnetic signature of CMBs and CMCs on internal field maps generated with 2DHF on 2D clinical datasets that give consistent results with CT-scans in a subsample of 10 subjects acquired with both modalities. PMID:25149849

Kaaouana, Takoua; de Rochefort, Ludovic; Samaille, Thomas; Thiery, Nathalie; Dufouil, Carole; Delmaire, Christine; Dormont, Didier; Chupin, Marie

2015-01-01

130

Measurements of Thermal Conductivity of Superfluid Helium Near its Transition Temperature T(sub lambda) in a 2D Confinement  

NASA Technical Reports Server (NTRS)

We report our recent experiments on thermal conductivity measurements of superfluid He-4 near its phase transition in a two-dimensional (2D) confinement under saturated vapor pressure. A 2D confinement is created by 2-mm- and 1-mm-thick glass capillary plates, consisting of densely populated parallel microchannels with cross-sections of 5 x 50 and 1 x 10 microns, correspondingly. A heat current (2 < Q < 400 nW/sq cm) was applied along the channels long direction. High-resolution measurements were provided by DC SQUID-based high-resolution paramagnetic salt thermometers (HRTs) with a nanokelvin resolution. We might find that thermal conductivity of confined helium is finite at the bulk superfluid transition temperature. Our 2D results will be compared with those in a bulk and 1D confinement.

Jerebets, Sergei

2004-01-01

131

Time resolved 2-D optical imaging of a pulsed unbalanced magnetron plasma  

NASA Astrophysics Data System (ADS)

Using wavelength filtered two dimensional (2-D) optical imaging, the temporal and spatial evolution of selected excited species in a pulsed magnetron discharge has been studied. A titanium target was sputtered at a pulse frequency of 100 kHz, in an argon atmosphere, at an operating pressure of 0.27 Pa. The radial information of the emissivity was determined using the Abel inversion technique. The results show strong excitation of the observed species above the racetrack in the on-time, and the possible development of an ion-acoustic wave, initiated after the off-on transition. The on-off transition is accompanied by a burst of light from the plasma bulk consistent with the transient plasma potential reaching about +200 V. During this phase, we argue that there is a release of secondary electrons from the grounded substrate and walls due to ion bombardment, as well as an increased confinement of energetic plasma electrons. The characteristic decay times of the selected transitions at 750.4, 751.5, 810.4 and 811.5 nm (ArI), present within the bandpass width of our filters, is briefly discussed in terms of the production of fast electrons in the system.

Bradley, J. W.; Clarke, G. C. B.; Braithwaite, N. St. J.; Bryant, P. M.; Kelly, P. J.

2006-05-01

132

Process to generate a synthetic diagnostic for microwave imaging reflectometry with the full-wave code FWR2D.  

PubMed

A synthetic microwave imaging reflectometer (MIR) diagnostic employing the full-wave reflectometer code (FWR2D) has been developed and is currently being used to guide the design of real systems, such as the one recently installed on DIII-D. The FWR2D code utilizes real plasma profiles as input, and it is combined with optical simulation tools for synthetic diagnostic signal generation. A detailed discussion of FWR2D and the process to generate the synthetic signal are presented in this paper. The synthetic signal is also compared to a prescribed density fluctuation spectrum to quantify the imaging quality. An example is presented with H-mode-like plasma profiles derived from a DIII-D discharge, where the MIR focal is located in the pedestal region. It is shown that MIR is suitable for diagnosing fluctuations with poloidal wavenumber up to 2.0 cm(-1) and fluctuation amplitudes less than 5%. PMID:25430276

Ren, X; Domier, C W; Kramer, G; Luhmann, N C; Muscatello, C M; Shi, L; Tobias, B J; Valeo, E

2014-11-01

133

2D/4D marker-free tumor tracking using 4D CBCT as the reference image  

NASA Astrophysics Data System (ADS)

Tumor motion caused by respiration is an important issue in image-guided radiotherapy. A 2D/4D matching method between 4D volumes derived from cone beam computed tomography (CBCT) and 2D fluoroscopic images was implemented to track the tumor motion without the use of implanted markers. In this method, firstly, 3DCBCT and phase-rebinned 4DCBCT are reconstructed from cone beam acquisition. Secondly, 4DCBCT volumes and a streak-free 3DCBCT volume are combined to improve the image quality of the digitally reconstructed radiographs (DRRs). Finally, the 2D/4D matching problem is converted into a 2D/2D matching between incoming projections and DRR images from each phase of the 4DCBCT. The diaphragm is used as a target surrogate for matching instead of using the tumor position directly. This relies on the assumption that if a patient has the same breathing phase and diaphragm position as the reference 4DCBCT, then the tumor position is the same. From the matching results, the phase information, diaphragm position and tumor position at the time of each incoming projection acquisition can be derived. The accuracy of this method was verified using 16 candidate datasets, representing lung and liver applications and one-minute and two-minute acquisitions. The criteria for the eligibility of datasets were described: 11 eligible datasets were selected to verify the accuracy of diaphragm tracking, and one eligible dataset was chosen to verify the accuracy of tumor tracking. The diaphragm matching accuracy was 1.88 ± 1.35 mm in the isocenter plane and the 2D tumor tracking accuracy was 2.13 ± 1.26 mm in the isocenter plane. These features make this method feasible for real-time marker-free tumor motion tracking purposes.

Wang, Mengjiao; Sharp, Gregory C.; Rit, Simon; Delmon, Vivien; Wang, Guangzhi

2014-05-01

134

Robustness and accuracy of feature-based single image 2-D-3-D registration without correspondences for image-guided intervention.  

PubMed

2-D-to-3-D registration is critical and fundamental in image-guided interventions. It could be achieved from single image using paired point correspondences between the object and the image. The common assumption that such correspondences can readily be established does not necessarily hold for image guided interventions. Intraoperative image clutter and an imperfect feature extraction method may introduce false detection and, due to the physics of X-ray imaging, the 2-D image point features may be indistinguishable from each other and/or obscured by anatomy causing false detection of the point features. These create difficulties in establishing correspondences between image features and 3-D data points. In this paper, we propose an accurate, robust, and fast method to accomplish 2-D-3-D registration using a single image without the need for establishing paired correspondences in the presence of false detection. We formulate 2-D-3-D registration as a maximum likelihood estimation problem, which is then solved by coupling expectation maximization with particle swarm optimization. The proposed method was evaluated in a phantom and a cadaver study. In the phantom study, it achieved subdegree rotation errors and submillimeter in-plane ( X- Y plane) translation errors. In both studies, it outperformed the state-of-the-art methods that do not use paired correspondences and achieved the same accuracy as a state-of-the-art global optimal method that uses correct paired correspondences. PMID:23955696

Xin Kang; Armand, Mehran; Otake, Yoshito; Wai-Pan Yau; Cheung, Paul Y S; Yong Hu; Taylor, Russell H

2014-01-01

135

Development and validation of a modelling framework for simulating 2D-mammography and breast tomosynthesis images  

NASA Astrophysics Data System (ADS)

Planar 2D x-ray mammography is generally accepted as the preferred screening technique used for breast cancer detection. Recently, digital breast tomosynthesis (DBT) has been introduced to overcome some of the inherent limitations of conventional planar imaging, and future technological enhancements are expected to result in the introduction of further innovative modalities. However, it is crucial to understand the impact of any new imaging technology or methodology on cancer detection rates and patient recall. Any such assessment conventionally requires large scale clinical trials demanding significant investment in time and resources. The concept of virtual clinical trials and virtual performance assessment may offer a viable alternative to this approach. However, virtual approaches require a collection of specialized modelling tools which can be used to emulate the image acquisition process and simulate images of a quality indistinguishable from their real clinical counterparts. In this paper, we present two image simulation chains constructed using modelling tools that can be used for the evaluation of 2D-mammography and DBT systems. We validate both approaches by comparing simulated images with real images acquired using the system being simulated. A comparison of the contrast-to-noise ratios and image blurring for real and simulated images of test objects shows good agreement ( < 9% error). This suggests that our simulation approach is a promising alternative to conventional physical performance assessment followed by large scale clinical trials.

Elangovan, Premkumar; Warren, Lucy M.; Mackenzie, Alistair; Rashidnasab, Alaleh; Diaz, Oliver; Dance, David R.; Young, Kenneth C.; Bosmans, Hilde; Strudley, Celia J.; Wells, Kevin

2014-08-01

136

Imaging of THz waves in 2D photonic crystal structures embedded in a slab waveguide  

E-print Network

We present space- and time-resolved simulations and measurements of single-cycle terahertz (THz) waves propagating through two-dimensional (2D) photonic crystal structures embedded in a slab waveguide. Specifically, we use ...

Peier, P.

137

Assessment of some problematic factors in facial image identification using a 2D/3D superimposition technique.  

PubMed

The number of criminal cases requiring facial image identification of a suspect has been increasing because a surveillance camera is installed everywhere in the city and furthermore, the intercom with the recording function is installed in the home. In this study, we aimed to analyze the usefulness of a 2D/3D facial image superimposition system for image identification when facial aging, facial expression, and twins are under consideration. As a result, the mean values of the average distances calculated from the 16 anatomical landmarks between the 3D facial images of the 50s groups and the 2D facial images of the 20s, 30s, and 40s groups were 2.6, 2.3, and 2.2mm, respectively (facial aging). The mean values of the average distances calculated from 12 anatomical landmarks between the 3D normal facial images and four emotional expressions were 4.9 (laughter), 2.9 (anger), 2.9 (sadness), and 3.6mm (surprised), respectively (facial expressions). The average distance obtained from 11 anatomical landmarks between the same person in twins was 1.1mm, while the average distance between different person in twins was 2.0mm (twins). Facial image identification using the 2D/3D facial image superimposition system demonstrated adequate statistical power and identified an individual with high accuracy, suggesting its usefulness. However, computer technology concerning video image processing and superimpose progress, there is a need to keep familiar with the morphology and anatomy as its base. PMID:23886899

Atsuchi, Masaru; Tsuji, Akiko; Usumoto, Yosuke; Yoshino, Mineo; Ikeda, Noriaki

2013-09-01

138

Numerical correction of anti-symmetric aberrations in single HRTEM images of weakly scattering 2D-objects.  

PubMed

Here, we present a numerical post-processing method for removing the effect of anti-symmetric residual aberrations in high-resolution transmission electron microscopy (HRTEM) images of weakly scattering 2D-objects. The method is based on applying the same aberrations with the opposite phase to the Fourier transform of the recorded image intensity and subsequently inverting the Fourier transform. We present the theoretical justification of the method, and its verification based on simulated images in the case of low-order anti-symmetric aberrations. Ultimately the method is applied to experimental hardware aberration-corrected HRTEM images of single-layer graphene and MoSe2 resulting in images with strongly reduced residual low-order aberrations, and consequently improved interpretability. Alternatively, this method can be used to estimate by trial and error the residual anti-symmetric aberrations in HRTEM images of weakly scattering objects. PMID:25458188

Lehtinen, Ossi; Geiger, Dorin; Lee, Zhongbo; Whitwick, Michael Brian; Chen, Ming-Wei; Kis, Andras; Kaiser, Ute

2014-10-27

139

Evaluation of an efficient GPU implementation of digitally reconstructed radiographs in 3D/2D image registration  

NASA Astrophysics Data System (ADS)

Intensity-based three-dimensional to two-dimensional (3D/2D) X-ray image registration algorithms usually require generating digitally reconstructed radiographs (DRRs) in every iteration during their optimization phase. Thus a large part of the computation time of such registration algorithms is spent in computing these DRRs. In a 3D-to-multiple-2D image registration framework where a sequence of DRRs is calculated, not only the computation but also the memory cost is high. We present an efficient DRR generation method to reduce both costs on a graphical processing units (GPU) implementation. The method relies on integrating a precomputation stage and a narrow-band region-of-interest calculation into the DRR generation. We have demonstrated its benefits on a previously proposed non-rigid 4D-to-multiple-2D image registration framework to estimate cerebral aneurysm wall motion. The two tested algorithms initially required several hours of highly intensive computation that involves generating a large number of DRRs in every iteration. In this paper, results on datasets of digital and physical pulsating cerebral aneurysm phantoms showed a speedup factor of around 50x in the generation of DRRs. In further image registration based wall motion estimation experiments using our implementation, we could obtain estimation results through the whole cardiac cycle within 5 minutes without degrading the overall performance.

Zhang, Chong; Villa-Uriol, Maria-Cruz; Frangi, Alejandro F.

2010-03-01

140

Paper by Our Team Jiang M, Wyatt CL, Wang G: X-ray phase-contrast imaging with three 2D gratings. To appear in Inter-  

E-print Network

. To appear in Inter- national Journal of Biomedical Imaging, 2007 (First paper on 2D grating-based xPaper by Our Team Jiang M, Wyatt CL, Wang G: X-ray phase-contrast imaging with three 2D gratings-ray imaging theory) Copyright by BID, VT-WFU SBSE, June 17, 2008; www.imaging.sbes.vt.edu X-ray Grating

Wang, Ge

141

Initial Images of the Synthetic Aperture Radiometer 2D-STAR  

Technology Transfer Automated Retrieval System (TEKTRAN)

Initial results obtained using a new synthetic aperture radiometer, 2D-STAR, a dual polarized, L-band radiometer that employs aperture synthesis in two dimensions are presented and analyzed. This airborne instrument is the natural evolution of a previous design that employed employs aperture synthes...

142

UNSUPERVISED 2D MULTIBAND HISTOGRAM CLUSTERING AND REGION MERGING FOR COLOR IMAGE SEGMENTATION  

E-print Network

regions are refined by a color watershed. The whole method requires the definition of only one single], edge-based methods [2], region growing methods [3], morphological watershed based region growing meth merging and watershed segmentation. In the first stage, 2D histograms are used to obtain a rapid

Lezoray, Olivier

143

2D BUILDING CHANGE DETECTION FROM HIGH RESOLUTION AERIAL IMAGES AND CORRELATION DIGITAL SURFACE MODELS  

Microsoft Academic Search

Updating 2D databases has become a crucial issue in most mapping agencies. Such a work traditionally starts out with a change detection phase. A subsequent update phase is then carried out to register changes in the up-to-date database. The first phase is by far the most costly and plodding, as it has until now required field or visual ins pection

Nicolas Champion

144

Comparing 2D matched filter response and Gabor filter methods for vessel segmentation in retinal images  

Microsoft Academic Search

Analysis of retinal blood vessels is extremely important for diagnosis and treatment of many diseases such as diabetic retinopathy, hypertension, glukoma, arteriosclerosis etc. Therefore, especially vessel segmentation is one of the most critical steps for detection and treatment of these diseases. In this paper, Gabor filter and 2D matched filter response methods, which are used to enhance blood vessels, were

Zafer Yavuz; Cemal Köse

2010-01-01

145

Application of Kohonen network for automatic point correspondence in 2D medical images  

Microsoft Academic Search

In this paper, a generalized application of Kohonen Network for automatic point correspondence of unimodal medical images is presented. Given a pair of two-dimensional medical images of the same anatomical region and a set of interest points in one of the images, the algorithm detects effectively the set of corresponding points in the second image, by exploiting the properties of

Vasiliki E. Markaki; Pantelis A. Asvestas; George K. Matsopoulos

2009-01-01

146

Beyond 2D-grids: a dependence maximization view on image browsing  

Microsoft Academic Search

Ideally, one would like to perform image search using an intuitive and friendly approach. Many existing image search engines, however, present users with sets of images arranged in some default order on the screen, typically the relevance to a query, only. While this certainly has its advantages, arguably, a more flexible and intuitive way would be to sort images into

Novi Quadrianto; Kristian Kersting; Tinne Tuytelaars; Wray L. Buntine

2010-01-01

147

Beyond 2D-Grids: A Dependence Maximization View on Image Browsing  

E-print Network

Ideally, one would like to perform image search using an in- tuitive and friendly approach. Many existing image search engines, however, present users with sets of images arranged in some default order interaction between a user and a web image search engine. A user executes a query and consid- ers hundreds

Ghahramani, Zoubin

148

Enhanced Understanding of MHD Dynamics & ELM Control Physics via 2D/3D ECE Imaging in KSTAR  

NASA Astrophysics Data System (ADS)

Enhanced physical understanding of the nature of the Edge Localized Mode (ELM) instability in the H-mode regime of toroidal plasmas requires advanced diagnostic tools to visualize their dynamics. A high spatial and temporal resolution 2-D Electron Cyclotron Emission Imaging (ECEI) system [1] was utilized successfully characterize the real time dynamics of ELMs [2] including the growth, saturation and bursting process of this instability during two campaigns (2010 and 2011) of the Korean Superconducting Tokamak Advanced Research (KSTAR) device. The measured ELMs are validated with the synthetic images based on numerical simulations.

Park, H. K.; Lee, J.; Yun, G. S.; Kim, M.; Choi, M. J.; Lee, W.; Domier, C. W.; Luhmann, N. C.; Jeon, Y. M.; Lee, S. G.; Xu, X. Q.

149

Direct observation of ground-state lactam–lactim tautomerization using temperature-jump transient 2D IR spectroscopy  

PubMed Central

We provide a systematic characterization of the nanosecond ground-state lactam–lactim tautomerization of pyridone derivatives in aqueous solution under ambient conditions using temperature-jump transient 2D IR spectroscopy. Although electronic excited-state tautomerization has been widely studied, experimental work on the ground electronic state, most relevant to chemistry and biology, is lacking. Using 2D IR spectroscopy, lactam and lactim tautomers of 6-chloro-2-pyridone and 2-chloro-4-pyridone are unambiguously identified by their unique cross-peak patterns. Monitoring the correlated exponential relaxation of these signals in response to a laser temperature jump provides a direct measurement of the nanosecond tautomerization kinetics. By studying the temperature, concentration, solvent, and pH dependence, we extract a thermodynamic and kinetic characterization and conclude that the tautomerization proceeds through a two-state concerted mechanism. We find that the intramolecular proton transfer is mediated by bridging water molecules and the reaction barrier is dictated by the release of a proton from pyridone, as would be expected for an efficient Grothuss-type proton transfer mechanism. PMID:23690588

Peng, Chunte Sam; Baiz, Carlos R.; Tokmakoff, Andrei

2013-01-01

150

Preoperative 3D to intraoperative low-resolution 3D and 2D sequences of MR images.  

PubMed

We have developed an automatic model-based deformable registration method applicable to MR soft-tissue imaging. The registration algorithm uses a dynamic finite element (FE) continuum mechanics model of the tissue deformation to register its 3D preoperative images with intraoperative 1) 3D low-resolution or 2) 2D MR images. The registration is achieved through a filtering process that combines information from the deformation model and observation errors based on correlation ratio, mutual information or sum of square differences between images. Experimental results with a breast phantom show that the proposed method converges in few iterations in the presence of very large deformations, similar to those typically observed in breast biopsy applications. PMID:22003650

Marami, Bahram; Sirouspour, Shahin; Capson, David W

2011-01-01

151

2D and 3D imaging resolution trade-offs in quantifying pore throats for prediction of permeability  

NASA Astrophysics Data System (ADS)

Although the impact of subsurface geochemical reactions on porosity is relatively well understood, changes in permeability remain difficult to estimate. In this work, pore-network modeling was used to predict permeability based on pore- and pore-throat size distributions determined from analysis of 2D scanning electron microscopy (SEM) images of thin sections and 3D X-ray computed microtomography (CMT) data. The analyzed specimens were a Viking sandstone sample from the Alberta sedimentary basin and an experimental column of reacted Hanford sediments. For the column, a decrease in permeability due to mineral precipitation was estimated, but the permeability estimates were dependent on imaging technique and resolution. X-ray CT imaging has the advantage of reconstructing a 3D pore network while 2D SEM imaging can easily analyze sub-grain and intragranular variations in mineralogy. Pore network models informed by analyses of 2D and 3D images at comparable resolutions produced permeability estimates with relatively good agreement. Large discrepancies in predicted permeabilities resulted from small variations in image resolution. Images with resolutions 0.4 to 4 ?m predicted permeabilities differing by orders of magnitude. While lower-resolution scans can analyze larger specimens, small pore throats may be missed due to resolution limitations, which in turn overestimates permeability in a pore-network model in which pore-to-pore conductances are statistically assigned. Conversely, high-resolution scans are capable of capturing small pore throats, but if they are not actually flow-conducting predicted permeabilities will be below expected values. In addition, permeability is underestimated due to misinterpreting surface-roughness features as small pore throats. Comparison of permeability predictions with expected and measured permeability values showed that the largest discrepancies resulted from the highest resolution images and the best predictions of permeability will result from images between 2 and 4 ?m resolution. To reduce permeability underestimation from analyses of high-resolution images, a resolution threshold between 3 and 15 ?m was found to be effective, but it is not known whether this range is applicable beyond the samples studied here.

Beckingham, L. E.; Peters, C. A.; Um, W.; Jones, K. W.; Lindquist, W. B.

2013-12-01

152

2D and 3D imaging resolution trade-offs in quantifying pore throats for prediction of permeability  

SciTech Connect

Although the impact of subsurface geochemical reactions on porosity is relatively well understood, changes in permeability remain difficult to estimate. In this work, pore-network modeling was used to predict permeability based on pore- and pore-throat size distributions determined from analysis of 2D scanning electron microscopy (SEM) images of thin sections and 3D X-ray computed microtomography (CMT) data. The analyzed specimens were a Viking sandstone sample from the Alberta sedimentary basin and an experimental column of reacted Hanford sediments. For the column, a decrease in permeability due to mineral precipitation was estimated, but the permeability estimates were dependent on imaging technique and resolution. X-ray CT imaging has the advantage of reconstructing a 3D pore network while 2D SEM imaging can easily analyze sub-grain and intragranular variations in mineralogy. Pore network models informed by analyses of 2D and 3D images at comparable resolutions produced permeability esti- mates with relatively good agreement. Large discrepancies in predicted permeabilities resulted from small variations in image resolution. Images with resolutions 0.4 to 4 lm predicted permeabilities differ- ing by orders of magnitude. While lower-resolution scans can analyze larger specimens, small pore throats may be missed due to resolution limitations, which in turn overestimates permeability in a pore-network model in which pore-to-pore conductances are statistically assigned. Conversely, high-res- olution scans are capable of capturing small pore throats, but if they are not actually flow-conducting predicted permeabilities will be below expected values. In addition, permeability is underestimated due to misinterpreting surface-roughness features as small pore throats. Comparison of permeability pre- dictions with expected and measured permeability values showed that the largest discrepancies resulted from the highest resolution images and the best predictions of permeability will result from images between 2 and 4 lm resolution. To reduce permeability underestimation from analyses of high-resolu- tion images, a resolution threshold between 3 and 15 lm was found to be effective, but it is not known whether this range is applicable beyond the samples studied here.

Beckingham, Lauren E.; Peters, Catherine A.; Um, Wooyong; Jones, Keith W.; Lindquist, W.Brent

2013-09-03

153

An image of Mt. Vesuvius obtained by 2D seismic tomography  

Microsoft Academic Search

A high-resolution seismic tomography of Mt.Vesuvius was started in May 1994, with the aim of reconstructing the detailed shallow crustal structure underneath the volcano and define its feeding system. The first phase of the experiment was to perform a 2D profile, using three underground explosions as active sources. Data from controlled sources and microearthquakes were jointly used to determine the

A. Zollo; P. Gasparini; J. Virieux; G. Biella; E. Boschi; P. Capuano; R. de Franco; R. de Matteis; G. De Natale; G. Iannaccone; I. Guerra; H. Le Meur; L. Mirabile

1998-01-01

154

Rate-Distortion Efficient Piecewise Planar 3-D Scene Representation From 2-D Images  

Microsoft Academic Search

In any practical application of the 2-D-to-3-D conversion that involves storage and transmission, representation efficiency has an undisputable importance that is not reflected in the attention the topic received. In order to address this problem, a novel algorithm, which yields efficient 3-D representations in the rate distortion sense, is proposed. The algorithm utilizes two views of a scene to build

Evren Imre; A. Aydin Alatan; Ugur Güdükbay

2009-01-01

155

GREIT: a unified approach to 2D linear EIT reconstruction of lung images  

E-print Network

reconstruction algorithm consists of: 1) detailed finite element models of a representative adult and neonatal Impedance Tomography, Lung Function Imaging, Image Reconstruction, 1. Introduction Electrical Impedance, Minneapolis, MN, USA 16 Institute of Child Health, University College London, UK Abstract. Electrical

Adler, Andy

156

Microphysical Analysis using Airborne 2-D Cloud and Precipitation Imaging Probe Data  

NASA Astrophysics Data System (ADS)

The NOAA P-3 instrumented aircraft provided in-situ cloud and precipitation microphysical observations during the DYNAMO (Dynamics of the Madden-Julian Oscillation) field experiment. The Particle Measuring System 2D cloud (2D-C) and precipitation (2D-P) probes collected data for particles between 12.5 ?m - 1.55 mm (25 ?m resolution) and 100 ?m - 6.2 mm (100 ?m resolution), respectively. Spectra from each instrument were combined to provide a broad distribution of precipitation particle sizes. The 'method of moments' technique was used to analyze drop size distribution (DSD) spectra, which were modeled by fitting a three-parameter (slope, shape, and intercept) gamma distribution to the spectra. The characteristic shape of the mean spectrum compares to previous maritime measurements. DSD variability will be presented with respect to the temporal evolution of cloud populations during a Madden-Julian Oscillation (MJO) event, as well as in-situ aircraft vertical wind velocity measurements. Using the third and sixth moments, rainfall rate (R) and equivalent radar reflectivity factor (Z), respectively, were computed for each DSD. Linear regression was applied to establish a Z-R relationship for the data for the estimation of precipitation. The study indicated unique characteristics of microphysical processes for this region. These results are important to continue to define the cloud population characteristics in the climatological MJO region. Improved representation of the cloud characteristics on the microphysical scale will serve as a check to model parameterizations, helping to improve numerical simulations.

Guy, N.; Jorgensen, D.; Witte, M.; Chuang, P. Y.; Black, R. A.

2013-12-01

157

Singleshot T1 Mapping using Simultaneous Acquisitions of Spin- and STimulated-Echo Planar Imaging (2D ss-SESTEPI)  

PubMed Central

The conventional stimulated-echo NMR sequence only measures the longitudinal component, while discarding the transverse component, after tipping up the prepared magnetization. This transverse magnetization can be used to measure a spin-echo, in addition to the stimulated-echo. 2D ss-SESTEPI is an EPI-based singleshot imaging technique that simultaneously acquires a spin-echo-planar image (SEPI) and a stimulated-echo-planar image (STEPI) after a single RF excitation. The magnitudes of SEPI and STEPI differ by T1 decay and diffusion weighting for perfect 90° RF, and thus can be used to rapidly measure T1. However, the spatial variation of B1 amplitude induces un-even splitting of the transverse magnetization for SEPI and STEPI within the imaging FOV. Correction for B1 inhomogeneity is therefore critical for 2D ss-SESTEPI to be used for T1 measurement. We developed a method for B1 inhomogeneity correction by acquiring an additional STEPI with minimal mixing time, calculating the difference between the spin-echo and the stimulated-echo and multiplying the STEPI by the inverse functional map. Diffusion-induced decay is corrected by measuring the average diffusivity during the prescanning. Rapid singleshot T1 mapping may be useful for various applications, such as dynamic T1 mapping for real-time estimation of the concentration of contrast agent in DCE-MRI. PMID:20564579

Shi, Xianfeng; Kim, Seong-Eun; Jeong, Eun-Kee

2011-01-01

158

State-of-the-art of 3D facial reconstruction methods for face recognition based on a single 2D training image per person  

Microsoft Academic Search

3D facial reconstruction systems attempt to reconstruct 3D facial models of individuals from their 2D photographic images or video sequences. Currently published face recognition systems, which exhibit well-known deficiencies, are largely based on 2D facial images, although 3D image capture systems can better encapsulate the 3D geometry of the human face. Accordingly, face recognition research is gradually shifting from the

Martin D. Levine; Yingfeng

2009-01-01

159

Iterative Stable Alignment and Clustering of 2D Transmission Electron Microscope Images  

PubMed Central

SUMMARY Identification of homogeneous subsets of images in a macromolecular electron microscopy (EM) image data set is a critical step in single-particle analysis. The task is handled by iterative algorithms, whose performance is compromised by the compounded limitations of image alignment and K-means clustering. Here we describe an approach, iterative stable alignment and clustering (ISAC) that, relying on a new clustering method and on the concepts of stability and reproducibility, can extract validated, homogeneous subsets of images. ISAC requires only a small number of simple parameters and, with minimal human intervention, can eliminate bias from two-dimensional image clustering and maximize the quality of group averages that can be used for ab initio three-dimensional structural determination and analysis of macromolecular conformational variability. Repeated testing of the stability and reproducibility of a solution within ISAC eliminates heterogeneous or incorrect classes and introduces critical validation to the process of EM image clustering. PMID:22325773

Yang, Zhengfan; Fang, Jia; Chittuluru, Johnathan; Asturias, Francisco J.; Penczek, Pawel A.

2012-01-01

160

2D discrete wavelet-transform implementation in FPGA device for real-time image processing  

NASA Astrophysics Data System (ADS)

A new approach to FPGA implementation of 2D discrete wavelet transform is presented. This architecture allow high accurate and sampling rate DWT realization based on FIR filters of substantial length to be implemented on current generation FPGAs. The scheme is based on two parallel pipelined linear phase 17-tap FIR filters with common shift register, partial adders and look-up tables as coefficient multipliers with 4-stage pipelined architecture. The transform is realized in three stages controlled by the state machine, where temporary (L and H) and final subimages (LL, LH, HL, and HH) are created. High throughput (1050 MIPS) and external memory controller allow efficiency concurrent cooperation with external processors.

Wasilewski, Piotr

1997-10-01

161

Soft-tissues Image Processing: Comparison of Traditional Segmentation Methods with 2D active Contour Methods  

NASA Astrophysics Data System (ADS)

The paper deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It focuses primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR). It is easy to describe edges of the sought objects using segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown. Research in the area of image segmentation focuses on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. In the paper, results of the segmentation of medical images by the active contour method are compared with results of the segmentation by other existing methods. Experimental applications which demonstrate the very good properties of the active contour method are given.

Mikulka, J.; Gescheidtova, E.; Bartusek, K.

2012-01-01

162

Magnetic resonance image reconstruction using trained geometric directions in 2D redundant wavelets domain and non-convex optimization.  

PubMed

Reducing scanning time is significantly important for MRI. Compressed sensing has shown promising results by undersampling the k-space data to speed up imaging. Sparsity of an image plays an important role in compressed sensing MRI to reduce the image artifacts. Recently, the method of patch-based directional wavelets (PBDW) which trains geometric directions from undersampled data has been proposed. It has better performance in preserving image edges than conventional sparsifying transforms. However, obvious artifacts are presented in the smooth region when the data are highly undersampled. In addition, the original PBDW-based method does not hold obvious improvement for radial and fully 2D random sampling patterns. In this paper, the PBDW-based MRI reconstruction is improved from two aspects: 1) An efficient non-convex minimization algorithm is modified to enhance image quality; 2) PBDW are extended into shift-invariant discrete wavelet domain to enhance the ability of transform on sparsifying piecewise smooth image features. Numerical simulation results on vivo magnetic resonance images demonstrate that the proposed method outperforms the original PBDW in terms of removing artifacts and preserving edges. PMID:23992629

Ning, Bende; Qu, Xiaobo; Guo, Di; Hu, Changwei; Chen, Zhong

2013-11-01

163

2D and 3D Refraction Based X-ray Imaging Suitable for Clinical and Pathological Diagnosis  

SciTech Connect

The first observation of micro papillary (MP) breast cancer by x-ray dark-field imaging (XDFI) and the first observation of the 3D x-ray internal structure of another breast cancer, ductal carcinoma in-situ (DCIS), are reported. The specimen size for the sheet-shaped MP was 26 mm x 22 mm x 2.8 mm, and that for the rod-shaped DCIS was 3.6 mm in diameter and 4.7 mm in height. The experiment was performed at the Photon Factory, KEK: High Energy Accelerator Research Organization. We achieved a high-contrast x-ray image by adopting a thickness-controlled transmission-type angular analyzer that allows only refraction components from the object for 2D imaging. This provides a high-contrast image of cancer-cell nests, cancer cells and stroma. For x-ray 3D imaging, a new algorithm due to the refraction for x-ray CT was created. The angular information was acquired by x-ray optics diffraction-enhanced imaging (DEI). The number of data was 900 for each reconstruction. A reconstructed CT image may include ductus lactiferi, micro calcification and the breast gland. This modality has the possibility to open up a new clinical and pathological diagnosis using x-ray, offering more precise inspection and detection of early signs of breast cancer.

Ando, Masami [Institute of Science and Technology, Tokyo Univ. of Science, Yamasaki 2641, Noda, Chiba 278-8510 (Japan); Photon Factory, IMSS, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Dept. of Photo-Science, GUAS, Shonan, Hayama, Kanagawa 240-0193 (Japan); Bando, Hiroko; Ueno, Ei [Dept. of Breast-Thyroid-Endocrine Surgery, Univ. of Tsukuba, Ibaraki 305-8573 (Japan)] (and others)

2007-01-19

164

Application of Kohonen network for automatic point correspondence in 2D medical images.  

PubMed

In this paper, a generalized application of Kohonen Network for automatic point correspondence of unimodal medical images is presented. Given a pair of two-dimensional medical images of the same anatomical region and a set of interest points in one of the images, the algorithm detects effectively the set of corresponding points in the second image, by exploiting the properties of the Kohonen self organizing maps (SOMs) and embedding them in a stochastic optimization framework. The correspondences are established by determining the parameters of local transformations that map the interest points of the first image to their corresponding points in the second image. The parameters of each transformation are computed in an iterative way, using a modification of the competitive learning, as implemented by SOMs. The proposed algorithm was tested on medical imaging data from three different modalities (CT, MR and red-free retinal images) subject to known and unknown transformations. The quantitative results in all cases exhibited sub-pixel accuracy. The algorithm also proved to work efficiently in the case of noise corrupted data. Finally, in comparison to a previously published algorithm that was also based on SOMs, as well as two widely used techniques for detection of point correspondences (template matching and iterative closest point), the proposed algorithm exhibits an improved performance in terms of accuracy and robustness. PMID:19481734

Markaki, Vasiliki E; Asvestas, Pantelis A; Matsopoulos, George K

2009-07-01

165

A 2-D gel electrophoresis DNA image analysis algorithm with automatic thresholding  

NASA Astrophysics Data System (ADS)

Polymerase chain reaction (PCR) and gel electrophoresis are two widely used techniques for genetic studies that require the bench scientist to perform many tedious manual steps. Advances in automation are making these techniques more accessible, but detection and image analysis still remain labor-intensive. Although several commercial software packages are now available, DNA image analysis still requires some intervention by the user, and thus a certain level of image processing expertise. To allow researchers to speed up their analyses and obtain more repeatable results, we present a fully automated image analysis system for DNA or protein studies with high accuracy. The proposed system is based mainly on four steps: automatic thresholding, shifting, filtering, and processing. The automatic thresholding that is used to equalize the gray values of the gel electrophoreses image background is one of the key and novel operations in this algorithm. An enhancement is also used to improve poor quality images that have faint DNA bands. Experimental results show that the proposed method eliminates defects due to noise for good and average quality gel electrophoresis images, while it also improves the appearance of poor quality images.

Kaabouch, Naima; Schultz, Richard R.

2007-01-01

166

Indirect multi-static 2D imaging within wireless sensor networks  

Microsoft Academic Search

A method for imaging within wireless sensor networks is described. It utilises signals that propagate along line of sight (LOS) paths between the objects. From mapping of the regions with LOS signal propagation the shape of objects is estimated. This information can be used for migration imaging of the whole scenario with improved quality.

Ole Hirsch; Rudolf Zetik; R. S. Thoma

2009-01-01

167

Contour segmentation in 2D ultrasound medical images with particle filtering  

Microsoft Academic Search

Object segmentation in medical images is an actively investigated research area. Segmentation techniques are a valuable tool in medical diagnostics for cancer tumors and cysts, for planning surgery op- erations and other medical treatment. In this paper a Monte Carlo algorithm for extracting lesion contours in ultrasound medical images is proposed. An e-cient multiple model particle fllter for progressive contour

Donka S. Angelova; Lyudmila Mihaylova

2011-01-01

168

Conformally mapped 2D ultrasonic array structure for NDT imaging application  

Microsoft Academic Search

Recent years have seen rapid increase in 2- Dimensional arrays for NDE imaging applications. This paper applies conformal mapping techniques as a means of designing non-periodic, sparse array transducers. Extensive field modeling using Huygens' principle is employed to study merits of the new array layout. Finally, an image processing methodology to conveniently compare various aperiodic designs is presented.

S. N. Ramadas; J. C. Jackson; A. Tweedie; R. L. O'Leary; A. Gachagan

2010-01-01

169

Using specularities in comparing 3D models and 2D images  

Microsoft Academic Search

We aim to create systems that identify and locate objects by comparing known, 3D shapes to intensity images that they have produced. To do this we focus on verification methods that determine whether a known model in a specific pose is consistent with an image. We build on prior work that has done this successfully for Lambertian objects, to handle

Margarita Osadchy; David Jacobs; Ravi Ramamoorthi; David Tucker

2008-01-01

170

Implementation of a new multiple monochromatic x-ray 2D imager at NIF  

NASA Astrophysics Data System (ADS)

We will describe the installation and wavelength calibration of a multiple monochromatic imager [MMI]1 to be used on mix experiments at National Ignition Facility [NIF]2. The imager works between 8 and 13 keV, has a spatial resolution of 16 micrometers and generates many images each with an energy bandwidth of ~80 eV. The images are recorded either on image plates or on gated x-ray detectors. We will describe: how we aligned the instrument on the bench using visible light, how we checked the alignment and determined the energy range using a k-alpha x-ray source, and how we installed and aligned the instrument to the NIF target chamber.

Kyrala, G. A.; Martinson, D.; Polk, P. J.; Gravlin, T.; Schmitt, M. J.; Johnson, R.; Murphy, T. J.; Lopez, F. E.; Oertel, J. A.; House, A.; Wood, R.; Lee, J.; Haugh, M.

2013-09-01

171

Spontaneous symmetry breaking in 2D: Kibble-Zurek mechanism in temperature quenched colloidal monolayers  

E-print Network

The Kibble-Zurek mechanism describes the formation of topological defects during spontaneous symmetry breaking for quite different systems. Shortly after the big bang, the isotropy of the Higgs-field is broken during the expansion and cooling of the universe. Kibble proposed the formation of monopoles, strings, and membranes in the Higgs field since the phase of the symmetry broken field can not switch globally to gain the same value everywhere in space. Zurek pointed out that the same mechanism is relevant for second order phase transitions in condensed matter systems. Every finite cooling rate induces the system to fall out of equilibrium which is due to the critical slowing down of order parameter fluctuations: the correlation time diverges and the symmetry of the system can not change globally but incorporates defects between different domains. Depending on the cooling rate the heterogeneous order parameter pattern are a fingerprint of critical fluctuations. In the present manuscript we show that a monolayer of superparamagnetic colloidal particles is ideally suited to investigate such phenomena. In thermal equilibrium the system undergos continuous phase transitions according KTHNY-theory. If cooled rapidly across the melting temperature the final state is a polycrystal. We show, that the observations can not be explained with nucleation of a supercooled fluid but is compatible with the Kibble-Zurek mechanism.

Patrick Dillmann; Georg Maret; Peter Keim

2014-09-16

172

2D and 3D PIC-MCC simulations of a low temperature magnetized plasma on CPU and GPU  

NASA Astrophysics Data System (ADS)

A Particle-In-Cell Monte Carlo Collisions model is used to described plasma transport in a low temperature magnetized plasma under conditions similar to those of the negative ion source for the neutral beam injector of ITER. A large diamagnetic electron current is present in the plasma because of the electron pressure gradient between the ICP driver of the source and the entrance of the magnetic filter, and is directed toward the chamber walls. The plasma potential adjusts to limit the diamagnetic electron current to the wall, leading to large electron current flow through the filter, and to a non uniform plasma density in the region between magnetic filter and extracting grids. On the basis of the PIC-MCC simulation results, we describe the plasma properties and electron current density distributions through the filter in 2D and 3D situations and use these models to better understand plasma transport across the filter in these conditions. We also present comparisons between computation times of two PIC-MCC simulation codes that have been developed for operations on standard CPU (Central Processing Units, code in Fortran) and on GPU (Graphics Processing Units, code in CUDA). The results show that the GPU simulation is about 25 times faster than the CPU one for a 2D domain with 512x512 grid points. The computation time ratio increases with the number of grid points.

Claustre, Jonathan; Chaudhury, Bhaskar; Fubiani, Gwenael; Boeuf, Jean-Pierre

2012-10-01

173

Improving object detection in 2D images using a 3D world model  

NASA Astrophysics Data System (ADS)

A mobile robot operating in a netcentric environment can utilize offboard resources on the network to improve its local perception. One such offboard resource is a world model built and maintained by other sensor systems. In this paper we present results from research into improving the performance of Deformable Parts Model object detection algorithms by using an offboard 3D world model. Experiments were run for detecting both people and cars in 2D photographs taken in an urban environment. After generating candidate object detections, a 3D world model built from airborne Light Detection and Ranging (LIDAR) and aerial photographs was used to filter out false alarm using several types of geometric reasoning. Comparison of the baseline detection performance to the performance after false alarm filtering showed a significant decrease in false alarms for a given probability of detection.

Viggh, Herbert E. M.; Cho, Peter L.; Armstrong-Crews, Nicholas; Nam, Myra; Shah, Danelle C.; Brown, Geoffrey E.

2014-05-01

174

2D-3D Rigid-Body Registration of X-Ray Fluoroscopy and CT Images  

E-print Network

The registration of pre-operative volumetric datasets to intra- operative two-dimensional images provides an improved way of verifying patient position and medical instrument loca- tion. In applications from orthopedics ...

Zollei, Lilla

2001-08-01

175

Magnetic resonance spectroscopic imaging with 2D spectroscopy for the detection of brain metabolites  

E-print Network

While magnetic resonance imaging (MRI) derives its signal from protons in water, additional biochemical compounds are detectable in vivo within the proton spectrum. The detection and mapping of these much weaker signals ...

Kok, Trina

2012-01-01

176

An active microwave imaging system for reconstruction of 2-D electrical property distributions.  

PubMed

The goal of this work is to develop a microwave-based imaging system for hyperthermia treatment monitoring and assessment. Toward this end, a four transmit channel and four receive channel hardware device and concomitant image reconstruction algorithm have been realized. The hardware is designed to measure electric fields (i.e., amplitude and phase) at various locations in a phantom tank with and without the presence of various heterogeneities using standard heterodyning principles. Particular attention has been paid to designing a receiver with better than 115 dB of linear dynamic range which is necessary for imaging biological tissue which often has very high conductivity, especially for tissues with high water content. A calibration procedure has been developed to compensate for signal loss due to three-dimensional radiation in the measured data, since the reconstruction process is only two-dimensional at the present time. Results are shown which demonstrate the stability and accuracy of the measurement system, the extent to which the forward computational model agrees with the measured field distribution when the electrical properties are known, and image reconstructions of electrically unknown targets of varying diameter. In the latter case, images of both the reactive and resistive component of the electrical property distribution have been recoverable. Quantitative information on object location, size, and electrical properties results when the target is approximately one-half wavelength in size. Images of smaller objects lack the same level of quantitative information, but remain qualitatively correct. PMID:8582719

Meaney, P M; Paulsen, K D; Hartov, A; Crane, R K

1995-10-01

177

Characterization of broadband MHD fluctuations during type-II edge localized modes as measured in 2D with ECE-imaging at ASDEX Upgrade  

NASA Astrophysics Data System (ADS)

The characterization of a broadband fluctuation that is typical for the type-II ELM regime at ASDEX Upgrade has been improved using the 2D capabilities of ECE-imaging. During the transition from the type-I to type-II ELMy phase, it has been found that electron temperature fluctuations form a broadband peak in the 19-65 kHz range. In the type-II phase, this broadband fluctuation reaches a maximum relative amplitude of almost 20% just inside the top of the pedestal. Simultaneously, the electron temperature profile is completely flattened at this location. The 2D distribution of the amplitude of this broadband fluctuation is such that, when averaged over time, a minimum occurs around the mid-plane. From the measurements of the nearby magnetic pickup coils, a similar broadband fluctuation seems visible in the same frequency range. However, this is peaked at a slightly lower frequency and does not show a similar minimum. From the analysis of the fluctuations on small timescales, the poloidal and toroidal mode numbers are estimated to be m ˜ 100 and n ˜ 21. Furthermore, activity reminiscent of beat waves has been observed, which might partially account for the fluctuation's broadband nature and the seeming velocity variation of single fluctuation passages. Overall, similarities between the characteristics of this broadband fluctuation and various precursors to type-I ELMs suggest that this fluctuation can play an important role in regulating the ELM cycle.

Boom, J. E.; Wolfrum, E.; Classen, I. G. J.; de Vries, P. C.; Maraschek, M.; Suttrop, W.; Pérez von Thun, C. P.; Donné, A. J. H.; Tobias, B. J.; Domier, C. W.; Luhmann, N. C., Jr.; Park, H. K.; the ASDEX Upgrade Team

2012-11-01

178

Photothermal converters for quantitative 2D and 3D real-time TeraHertz imaging  

Microsoft Academic Search

Recent advances for the measurement of TeraHertz (THz) radiation by using original IR temperature flux sensors are presented. The bolometer principle is used for designing simple thermal converters for THz radiations (measurement of the temperature increase of a sensitive absorber). Most of these sensors are efficient, sensitive and fast enough for quantitative measurement of THz source power as well as

Christophe Pradere; Jean-Pascal Caumes; Daniel Balageas; Simon Salort; Emmanuel Abraham; Bruno Chassagne; Jean-Christophe Batsale

2010-01-01

179

Tracking contrast agents using real-time 2D photoacoustic imaging system for cardiac applications  

NASA Astrophysics Data System (ADS)

Photoacoustic (PA) imaging is a rapidly developing imaging modality that can detect optical contrast agents with high sensitivity. While detectors in PA imaging have traditionally been single element ultrasound transducers, use of array systems is desirable because they potentially provide high frame rates to capture dynamic events, such as injection and distribution of contrast in clinical applications. We present preliminary data consisting of 40 second sequences of coregistered pulse-echo (PE) and PA images acquired simultaneously in real time using a clinical ultrasonic machine. Using a 7 MHz linear array, the scanner allowed simultaneous acquisition of inphase-quadrature (IQ) data on 64 elements at a rate limited by the illumination source (Q-switched laser at 20 Hz) with spatial resolution determined to be 0.6 mm (axial) and 0.4 mm (lateral). PA images had a signal-to-noise ratio of approximately 35 dB without averaging. The sequences captured the injection and distribution of an infrared-absorbing contrast agent into a cadaver rat heart. From these data, a perfusion time constant of 0.23 s-1 was estimated. After further refinement, the system will be tested in live animals. Ultimately, an integrated system in the clinic could facilitate inexpensive molecular screening for coronary artery disease.

Olafsson, Ragnar; Montilla, Leonardo; Ingram, Pier; Witte, Russell S.

2009-02-01

180

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative  

NASA Astrophysics Data System (ADS)

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications.

Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; MacDonald, J. E.

2013-11-01

181

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative.  

PubMed

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications. PMID:24284731

Lilliu, S; Maragliano, C; Hampton, M; Elliott, M; Stefancich, M; Chiesa, M; Dahlem, M S; Macdonald, J E

2013-01-01

182

EFM data mapped into 2D images of tip-sample contact potential difference and capacitance second derivative  

PubMed Central

We report a simple technique for mapping Electrostatic Force Microscopy (EFM) bias sweep data into 2D images. The method allows simultaneous probing, in the same scanning area, of the contact potential difference and the second derivative of the capacitance between tip and sample, along with the height information. The only required equipment consists of a microscope with lift-mode EFM capable of phase shift detection. We designate this approach as Scanning Probe Potential Electrostatic Force Microscopy (SPP-EFM). An open-source MATLAB Graphical User Interface (GUI) for images acquisition, processing and analysis has been developed. The technique is tested with Indium Tin Oxide (ITO) and with poly(3-hexylthiophene) (P3HT) nanowires for organic transistor applications. PMID:24284731

Lilliu, S.; Maragliano, C.; Hampton, M.; Elliott, M.; Stefancich, M.; Chiesa, M.; Dahlem, M. S.; Macdonald, J. E.

2013-01-01

183

Least-square NUFFT methods applied to 2-D and 3-D radially encoded MR image reconstruction.  

PubMed

Radially encoded MRI has gained increasing attention due to its motion insensitivity and reduced artifacts. However, because its samples are collected nonuniformly in the k-space, multidimensional (especially 3-D) radially sampled MRI image reconstruction is challenging. The objective of this paper is to develop a reconstruction technique in high dimensions with on-the-fly kernel calculation. It implements general multidimensional nonuniform fast Fourier transform (NUFFT) algorithms and incorporates them into a k-space image reconstruction framework. The method is then applied to reconstruct from the radially encoded k-space data, although the method is applicable to any non-Cartesian patterns. Performance comparisons are made against the conventional Kaiser-Bessel (KB) gridding method for 2-D and 3-D radially encoded computer-simulated phantoms and physically scanned phantoms. The results show that the NUFFT reconstruction method has better accuracy-efficiency tradeoff than the KB gridding method when the kernel weights are calculated on the fly. It is found that for a particular conventional kernel function, using its corresponding deapodization function as a scaling factor in the NUFFT framework has the potential to improve accuracy. In particular, when a cosine scaling factor is used, the NUFFT method is faster than KB gridding method since a closed-form solution is available and is less computationally expensive than the KB kernel (KB griding requires computation of Bessel functions). The NUFFT method has been successfully applied to 2-D and 3-D in vivo studies on small animals. PMID:19174334

Song, Jiayu; Liu, Yanhui; Gewalt, Sally L; Cofer, Gary; Johnson, G Allan; Liu, Qing Huo

2009-04-01

184

Nonrigid Point Registration for 2D Curves and 3D Surfaces and its Applications in Small Animal Imaging  

PubMed Central

A nonrigid B-spline based point-matching method (BPM) is proposed to match dense surface points. The method solves both the point correspondence and nonrigid transformation without features extraction. The registration method integrates a motion model, which combines a global transformation and a B-spline based local deformation, into a robust point-matching framework. The point correspondence and deformable transformation are estimated simultaneously by fuzzy correspondence and by a deterministic annealing technique. Prior information about global translation, rotation and scaling is incorporated into the optimization. A local B-spline motion model decreases the degrees of freedom for optimization and thus enables the registration of a larger number of feature points. The performance of the BPM method has been demonstrated and validated using synthesized 2D and 3D data, mouse MRI, and micro-CT images. The proposed B-spline point-matching method can be used to register feature point sets, 2D curves, 3D surfaces, and various image data. PMID:23732538

Wang, Hesheng; Fei, Baowei

2013-01-01

185

Temperature-tuning of transmission spectra of 2D photonic crystals made of a semiconductor with free electrons.  

NASA Astrophysics Data System (ADS)

We have studied theoretically the electromagnetic transmittance in finite samples of InSb-based 2D photonic crystals. Due to the temperature dependence of the intrinsic carrier concentration in this semiconductor, the triangular and square arrays of parallel InSb cylinders in air - or vice versa, parallel hole cylinders in InSb - give rise to tunable transmission spectra. As the temperature increases from 200 to 300 K the mid-gap frequencies move up in frequency while the widths of the gaps diminish in agreement with the bulk band structure.[1] The wave transmittance was calculated taking into account the dispersion due to phonons, as well as free charge carriers; absorptive mechanisms due to phonons, holes and electrons were also considered. We also studied tuning of localized modes due to linear defects. The corresponding transmittance peaks reveal considerable dependence on the temperature. This work was financially supported by CONACyT, Mexico, Grant No. 41195-F. [1] P. Halevi and F. Ramos-Mendieta, Phys. Rev. Lett. 85, 1875 (2000)

Manzanares-Martinez, Jesus; Ramos-Mendieta, Felipe; Halevi, Peter

2004-03-01

186

Characterization of saturated MHD instabilities through 2D electron temperature profile reconstruction from 1D ECE measurements  

NASA Astrophysics Data System (ADS)

A new method for the reconstruction of two-dimensional (2D) electron temperature profiles in the presence of saturated magneto-hydro-dynamic (MHD) modes from the one-dimensional (1D) electron cyclotron emission (ECE) diagnostic is presented. The analysis relies on harmonic decomposition of the electron temperature oscillations through short time Fourier transforms and requires rigid poloidal mode rotation as the only assumption. The method is applicable to any magnetic perturbation as long as the poloidal and toroidal mode numbers m and n are known. Its application to the case of a (m, n) = (1, 1) internal kink mode on ASDEX Upgrade is presented and a new way to estimate the mode displacement is explained. For such modes, it is shown that the higher order harmonics usually visible in the ECE spectrogram arise also for the pure m = n = 1 mode and that they cannot be directly associated with m = n > 1 magnetic perturbations. This method opens up new possibilities for electron heat transport studies in the presence of saturated MHD modes and a way to disentangle the impurity density contributions from electron temperature effects in the analysis of the soft x-ray data.

Sertoli, M.; Horváth, L.; Pokol, G. I.; Igochine, V.; Barrera, L.

2013-05-01

187

REAL-TIME TEXTURE ANALYSIS FOR IDENTIFYING OPTIMUM MICROBUBBLE CONCENTRATION IN 2-D ULTRASONIC PARTICLE IMAGE VELOCIMETRY  

PubMed Central

Many recent studies on ultrasonic particle image velocimetry (Echo PIV) showed that the accuracy of two-dimensional (2-D) flow velocity measured depends largely on the concentration of ultrasound contrast agents (UCAs) during imaging. This article presents a texture-based method for identifying the optimum microbubble concentration for Echo PIV measurements in real-time. The texture features, standard deviation of gray level, and contrast, energy and homogeneity of gray level co-occurrence matrix were extracted from ultrasound contrast images of rotational and pulsatile flow (10 MHz) in vitro and in vivo mouse common carotid arterial flow (40 MHz) with UCAs at various concentrations. The results showed that, at concentration of 0.8~2 × 103 bubbles/mL in vitro and 1~5 × 105 bubbles/mL in vivo, image texture features had a peak value or trough value, and velocity vectors with high accuracy can be obtained. Otherwise, poor quality velocity vectors were obtained. When the texture features were used as a feature set, the accuracy of K-nearest neighbor classifier can reach 86.4% in vitro and 87.5% in vivo, respectively. The texture-based method is shown to be able to quickly identify the optimum microbubble concentration and improve the accuracy for Echo PIV imaging. PMID:21684062

Niu, Lili; Qian, Ming; Yan, Liang; Yu, Wentao; Jiang, Bo; Jin, Qiaofeng; Wang, Yanping; Shandas, Robin; Liu, Xin; Zheng, Hairong

2013-01-01

188

Implementation of the 2-D Wavelet Transform into FPGA for Image  

NASA Astrophysics Data System (ADS)

This paper presents a hardware system implementation of the of discrete wavelet transform algoritm in two dimensions for FPGA, using the Daubechies filter family of order 2 (db2). The decomposition algorithm of this transform is designed and simulated with the Hardware Description Language VHDL and is implemented in a programmable logic device (FPGA) XC3S1200E reference, Spartan IIIE family, by Xilinx, take advantage the parallels properties of these gives us and speeds processing that can reach them. The architecture is evaluated using images input of different sizes. This implementation is done with the aim of developing a future images encryption hardware system using wavelet transform for security information.

León, M.; Barba, L.; Vargas, L.; Torres, C. O.

2011-01-01

189

IEEE Visualization 2005 -Tutorial (Image Processing 2D) Point Lattices in Computer Graphics  

E-print Network

de Lausanne Biomedical Imaging Group dimitri.vandeville@epfl.ch #12;2 Overview B-splines: the right one-sided Fourier transform Z-transform #12;4 B-spline of degree n Symmetric B-spline Key properties · compact support · piecewise polynomial · positivity · smoothness (continuity) Polynomial B-splines

Zhang, Richard "Hao"

190

Single-snapshot 2D color measurement by plenoptic imaging system  

NASA Astrophysics Data System (ADS)

Plenoptic cameras enable capture of directional light ray information, thus allowing applications such as digital refocusing, depth estimation, or multiband imaging. One of the most common plenoptic camera architectures contains a microlens array at the conventional image plane and a sensor at the back focal plane of the microlens array. We leverage the multiband imaging (MBI) function of this camera and develop a single-snapshot, single-sensor high color fidelity camera. Our camera is based on a plenoptic system with XYZ filters inserted in the pupil plane of the main lens. To achieve high color measurement precision of this system, we perform an end-to-end optimization of the system model that includes light source information, object information, optical system information, plenoptic image processing and color estimation processing. Optimized system characteristics are exploited to build an XYZ plenoptic colorimetric camera prototype that achieves high color measurement precision. We describe an application of our colorimetric camera to color shading evaluation of display and show that it achieves color accuracy of ?E<0.01.

Masuda, Kensuke; Yamanaka, Yuji; Maruyama, Go; Nagai, Sho; Hirai, Hideaki; Meng, Lingfei; Tosic, Ivana

2014-03-01

191

Class-specific grasping of 3D objects from a single 2D image  

E-print Network

Our goal is to grasp 3D objects given a single image, by using prior 3D shape models of object classes. The shape models, defined as a collection of oriented primitive shapes centered at fixed 3D positions, can be learned ...

Chiu, Han-Pang

192

Finite Element Methods for Active Contour Models and Balloons for 2D and 3D Images  

Microsoft Academic Search

The use of energy-minimizing curves, known as "snakes" to extract features of interest in images has been introduced by Kass, Witkin and Terzopoulos [23]. A balloon model was introduced in [12] as a way to generalize and solve some of the problems encountered with the original method. We present a 3D generalization of the balloon model as a 3D deformable

Laurent D. Cohen; Isaac Cohen

1991-01-01

193

Flow around Helicopter Blade Tip Sections Using a 2d Particle Image Velocimeter - Part I  

Microsoft Academic Search

The current study is an effort to better understand the viscous flow physics existing near helicopter blade tips at various angle of attack positions. A planar particle image velocimeter (PIV) was successfully integrated into the helicopter blade tip flow measurement system in a model hover stand The current study utilizes a 1200 mm (47.24 in) diameter scaled helicopter rotor blade

Harika S. Kahveci; Cengiz Camci

194

Similarity metrics based on nonadditive entropies for 2D-3D multimodal biomedical image registration  

Microsoft Academic Search

Information theoretic similarity metrics, including mutual information, have been widely and successfully employed in multimodal biomedical image registration. These metrics are generally based on the Shannon-Boltzmann-Gibbs definition of entropy. However, other entropy definitions exist, including generalized entropies, which are parameterized by a real number. New similarity metrics can be derived by exploiting the additivity and pseudoadditivity properties of these entropies.

Mark P. Wachowiak; Renata Smolíková; Georgia D. Tourassi; Adel S. Elmaghraby

195

Ignition and early soot formation in a DI diesel engine using multiple 2-D imaging diagnostics  

NASA Astrophysics Data System (ADS)

Combined optical imaging diagnostics in the fuel jet of a direct-injection diesel engine to study the ignition and early soot formation processes. A diesel engine of the 'heavy-duty' size class was operated at a representative medium speed (1200 rpm) operating condition. Two fuels were used, a 42.5 cetane number mixture of the diesel reference fuels and a new low-sooting fuel. Combustion and soot formation are almost identical for both fuels. Ignition and early combustion were studied by imaging the natural chemiluminescence using a calibrated intensified video camera. Early soot development was investigated via luminosity imaging and simultaneous planar imaging of laser-induced incandescence (LII) and elastic scattering. The latter provide relative soot concentrations and particle size distributions. Data show that ignition occurs at multiple points across the downstream region of all the fuel jets prior to first apparent heat release well before any soot luminosity occurs. Quantitative vapor-fuel/air mixture images in the leading portion of the jet are also presented and discussed with respect to the early combustion data. The first soot occurs at random locations, and shortly thereafter, small soot particles develop throughout the cross section of the leading portion of the jet. Data indicate that this soot arises from the fuel-rich premixed burn. Then, significantly larger soot particles appear around the periphery of the jet, presumably from the initial diffusion combustion. By the end of the premixed burn, the soot has developed a distribution pattern of a higher concentration toward the front of the jet and a lower concentration upstream, with the larger-sized soot particles being generally confined to the periphery of the jet.

Dec, John E.; Espey, Christoph

196

Automatic Characterization of the Physiological Condition of the Carotid Artery in 2D Ultrasound Image Sequences Using Spatiotemporal and Spatiospectral 2D Maps  

PubMed Central

A novel method for characterizing and visualizing the progression of waves along the walls of the carotid artery is presented. The new approach is noninvasive and able to simultaneously capture the spatial and the temporal propagation of wavy patterns along the walls of the carotid artery in a completely automated manner. Spatiotemporal and spatiospectral 2D maps describing these patterns (in both the spatial and the frequency domains, resp.) were generated and analyzed by visual inspection as well as automatic feature extraction and classification. Three categories of cases were considered: pathological elderly, healthy elderly, and healthy young cases. Automatic differentiation, between cases of these three categories, was achieved with a sensitivity of 97.1% and a specificity of 74.5%. Two features were proposed and computed to measure the homogeneity of the spatiospectral 2D map which presents the spectral characteristics of the carotid artery wall's wavy motion pattern which are related to the physical, mechanical (e.g., elasticity), and physiological properties and conditions along the artery. These results are promising and confirm the potential of the proposed method in providing useful information which can help in revealing the physiological condition of the cardiovascular system. PMID:24971088

Hamid Muhammed, Hamed; Azar, Jimmy C.

2014-01-01

197

Performance evaluation of 2-D adaptive prediction filters for detection of small objects in image data  

Microsoft Academic Search

This paper studies the performance of two dimensional least mean square(TDLMS)adaptive filters as prewhitening filters for the detection of small objects in image data.The object of interest is assumed to have a very small spatial spread and is obscured bycorrelated clutter of much larger spatial extent. The correlated clutter is predicted andsubtracted from the input signal, leaving components of the

Tarun Soni; James R. Zeidler; Walter H. Ku

1993-01-01

198

Instantaneous 2D velocity and temperature measurements in high speed flows based on spectrally resolved molecular Rayleigh scattering  

NASA Astrophysics Data System (ADS)

A Rayleigh scattering diagnostic for high speed flows is described for the simultaneous, instantaneous measurement of gas temperature and velocity at a number (up to about one hundred) of locations in a plane illuminated by an injection-seeded, frequency doubled Nd:YAG laser. Molecular Rayleigh scattered light is collected and passed through a planar mirror Fabry-Perot interferometer. The resulting image is analyzed to determine the gas temperature and bulk velocity at each of the regions. The Cramer Rao lower bound for measurement uncertainty is calculated. Experimental data is presented for a free jet and for preliminary measurements in the Lewis 4 inch by 10 inch supersonic wind tunnel.

Seasholtz, Richard G.

1995-03-01

199

Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility study ex vivo  

Microsoft Academic Search

Magnetic resonance imaging (MRI) and ultrasonography have been used simultaneously in this ex vivo study for the image-guidance of high intensity focused ultrasound (HIFU) treatment in moving tissue. A ventilator-driven balloon produced periodic and non-rigid (i.e. breathing-like) motion patterns in phantoms. MR-compatible ultrasound (US) imaging enabled near real-time 2D motion tracking based on optical flow detection, while near-harmonic reference-free proton

Vincent Auboiroux; Lorena Petrusca; Magalie Viallon; Thomas Goget; Christoph D Becker; Rares Salomir

2012-01-01

200

Distributed Computing Architecture for Image-Based Wavefront Sensing and 2 D FFTs  

NASA Technical Reports Server (NTRS)

Image-based wavefront sensing (WFS) provides significant advantages over interferometric-based wavefi-ont sensors such as optical design simplicity and stability. However, the image-based approach is computational intensive, and therefore, specialized high-performance computing architectures are required in applications utilizing the image-based approach. The development and testing of these high-performance computing architectures are essential to such missions as James Webb Space Telescope (JWST), Terrestial Planet Finder-Coronagraph (TPF-C and CorSpec), and Spherical Primary Optical Telescope (SPOT). The development of these specialized computing architectures require numerous two-dimensional Fourier Transforms, which necessitate an all-to-all communication when applied on a distributed computational architecture. Several solutions for distributed computing are presented with an emphasis on a 64 Node cluster of DSPs, multiple DSP FPGAs, and an application of low-diameter graph theory. Timing results and performance analysis will be presented. The solutions offered could be applied to other all-to-all communication and scientifically computationally complex problems.

Smith, Jeffrey S.; Dean, Bruce H.; Haghani, Shadan

2006-01-01

201

Diffraction Analysis of 2-D Pupil Mapping for High-Contrast Imaging  

E-print Network

Pupil-mapping is a technique whereby a uniformly-illuminated input pupil, such as from starlight, can be mapped into a non-uniformly illuminated exit pupil, such that the image formed from this pupil will have suppressed sidelobes, many orders of magnitude weaker than classical Airy ring intensities. Pupil mapping is therefore a candidate technique for coronagraphic imaging of extrasolar planets around nearby stars. Unlike most other high-contrast imaging techniques, pupil mapping is lossless and preserves the full angular resolution of the collecting telescope. So, it could possibly give the highest signal-to-noise ratio of any proposed single-telescope system for detecting extrasolar planets. Prior analyses based on pupil-to-pupil ray-tracing indicate that a planet fainter than 10^{-10} times its parent star, and as close as about 2 lambda/D, should be detectable. In this paper, we describe the results of careful diffraction analysis of pupil mapping systems. These results reveal a serious unresolved issue. Namely, high-contrast pupil mappings distribute light from very near the edge of the first pupil to a broad area of the second pupil and this dramatically amplifies diffraction-based edge effects resulting in a limiting attainable contrast of about 10^{-5}. We hope that by identifying this problem others will provide a solution.

R. J. Vanderbei

2005-06-22

202

Push-broom hyperspectral image calibration and enhancement by 2D deconvolution with a variant response function estimate.  

PubMed

In this paper, we propose a novel method for spectral and spatial calibration and resolution enhancement of hyperspectral images by a two-step procedure. The spectral and spatial variability of the hyperspectral imaging system response function is characterized by a global parametric model, which is derived from a pair of calibration images corresponding to an exactly defined calibration target and a set of gas-discharge lamps. A 2D Richardson-Lucy deconvolution-based algorithm is used to remove the distortions and enhance the resolution of subsequently acquired hyperspectral images. The results of the characterization and deconvolution process obtained by the proposed method are thoroughly evaluated by an independent set of exactly defined calibration and spectral targets, and compared to the existing state-of-the-art characterization method. The proposed method significantly improves the spectral and spatial coregistration and provides more than five-fold resolution enhancement in the spatial and two-fold resolution enhancement in the spectral domain. PMID:25401909

Jemec, Jurij; Pernuš, Franjo; Likar, Boštjan; Bürmen, Miran

2014-11-01

203

2-D tomographic imaging of continental crust and relic slab beneath Baja California  

NASA Astrophysics Data System (ADS)

Rifting of Baja California from the margin of North America began as, or sometime before, subduction of the Farallon plate ceased (~12 Ma). Many have speculated that increased coupling between the subducted Farallon slab and overriding plate caused the young upper part of the subducted plate to detach from the older, colder, sinking slab. Then as the fragments of the Farallon plate took on Pacific plate motion, traction forces between the relic slab and Baja influenced rift localization in the Gulf of California. To better understand the processes that led to rifting of the Baja peninsula a 350 km seismic refraction/reflection profile was collected in 2002 in an effort to constrain the crustal thickness, the extent of relic slab beneath Baja California and the upper mantle P-wave velocities. The line spans the Baja Peninsula from the paleo-trench to the central Gulf of California, between the Farallon and Pescadero basins. 13 Ocean-Bottom Seismometers and 8 onshore Ref-Tek portable seismometers recorded 35,504 airgun shots from the R/V Ewing. Multichannel seismic (MCS) reflection profiles were collected on either side of the peninsula, providing information on the upper crustal structure and style of post-subduction deformation, particularly along the Tosco-Abreojos and Santa Margarita-San Lazaro fault systems. Here we present the integrated results of the MCS profiles and 2-D travel time tomography. Ray tracing was performed on 13,388 arrival picks, including Pg, Pn and PmP arrivals. Initial tomographic inversions reveal a crustal root beneath Baja California with an average velocity of 6.0 km/s. Continental crust thins to the east into the Gulf of California and has a velocity structure consistent with that of the Alarcon segment of the PESCADOR experiment. Perhaps the most significant observation is an ~6 km thick, 8° east-dipping high velocity zone (mean of 6.7 km/s) that underplates the western Baja margin and extends at least 60 km from the former trench (~40 km west of the shoreline). We interpret this to be relic oceanic crust. We are investigating the extent of the relic slab beneath Baja and its relationship with high-Mg adakitic volcanics exposed on Isla Margarita, ~20 km north of the seismic transect. The existence of a stalled slab beneath the Baja margin suggests frictional and/or viscous coupling along the paleo-subduction interface is an important process in for the geodynamical development of the Gulf of California rift system.

Brothers, D. S.; Harding, A. J.; Kent, G.; Driscoll, N.

2009-12-01

204

2D and 3D GPR imaging of structural ceilings in historic and existing constructions  

NASA Astrophysics Data System (ADS)

GPR applications in civil engineering are to date quite diversified. With respect to civil constructions and monumental buildings, detection of voids, cavities, layering in structural elements, variation of geometry, of moisture content, of materials, areas of decay, defects, cracks have been reported in timber, concrete and masonry elements. Nonetheless, many more fields of investigation remain unexplored. This contribution gives an account of a variety of examples of structural ceilings investigation by GPR radar in reflection mode, either as 2D or 3D data acquisition and visualisation. Ceilings have a pre-eminent role in buildings as they contribute to a good structural behaviour of the construction. Primarily, the following functions can be listed for ceilings: a) they carry vertical dead and live loads on floors and distribute such loads to the vertical walls; b) they oppose to external horizontal forces such as wind loads and earthquakes helping to transfer such forces from the loaded element to the other walls; c) they contribute to create the box skeleton and behaviour of a building, connecting the different load bearing walls and reducing the slenderness and flexural instability of such walls. Therefore, knowing how ceilings are made in specific buildings is of paramount importance for architects and structural engineers. According to the type of building and age of construction, ceilings may present very different solutions and materials. Moreover, in existing constructions, ceilings may have been substituted, modified or strengthened due to material decay or to change of use of the building. These alterations may often go unrecorded in technical documentation or technical drawings may be unavailable. In many cases, the position, orientation and number of the load carrying elements in ceilings may be hidden or not be in sight, due for example to the presence of false ceilings or to technical plants. GPR radar can constitute a very useful tool for investigating with rapidity and high resolution, thin as well as very thick ceilings, in a non-destructive manner. Ceilings may be made up as masonry vaults or timber/metal/concrete beams and elements laid down in one or two directions or, again, can be made as a combination of the above. A number of cases are here presented reporting on typical features to be recognised in radargrams in order to distinguish the material and possible shape of the relevant objects with the aim of providing a first small catalogue useful to the radar user and to professionals. This abstract is of interest for COST Action TU1208.

Colla, Camilla

2014-05-01

205

Tangential 2-D Edge Imaging for GPI and Edge/Impurity Modeling  

SciTech Connect

Nova Photonics, Inc. has a collaborative effort at the National Spherical Torus Experiment (NSTX). This collaboration, based on fast imaging of visible phenomena, has provided key insights on edge turbulence, intermittency, and edge phenomena such as edge localized modes (ELMs) and multi-faceted axisymmetric radiation from the edge (MARFE). Studies have been performed in all these areas. The edge turbulence/intermittency studies make use of the Gas Puff Imaging diagnostic developed by the Principal Investigator (Ricardo Maqueda) together with colleagues from PPPL. This effort is part of the International Tokamak Physics Activity (ITPA) edge, scrape-off layer and divertor group joint activity (DSOL-15: Inter-machine comparison of blob characteristics). The edge turbulence/blob study has been extended from the current location near the midplane of the device to the lower divertor region of NSTX. The goal of this effort was to study turbulence born blobs in the vicinity of the X-point region and their circuit closure on divertor sheaths or high density regions in the divertor. In the area of ELMs and MARFEs we have studied and characterized the mode structure and evolution of the ELM types observed in NSTX, as well as the study of the observed interaction between MARFEs and ELMs. This interaction could have substantial implications for future devices where radiative divertor regions are required to maintain detachment from the divertor plasma facing components.

Dr. Ricardo Maqueda; Dr. Fred M. Levinton

2011-12-23

206

SIMS of organics—Advances in 2D and 3D imaging and future outlook  

SciTech Connect

Secondary ion mass spectrometry (SIMS) has become a powerful technique for the label-free analysis of organics from cells to electronic devices. The development of cluster ion sources has revolutionized the field, increasing the sensitivity for organics by two or three orders of magnitude and for large clusters, such as C{sub 60} and argon clusters, allowing depth profiling of organics. The latter has provided the capability to generate stunning three dimensional images with depth resolutions of around 5 nm, simply unavailable by other techniques. Current state-of-the-art allows molecular images with a spatial resolution of around 500 nm to be achieved and future developments are likely to progress into the sub-100 nm regime. This review is intended to bring those with some familiarity with SIMS up-to-date with the latest developments for organics, the fundamental principles that underpin this and define the future progress. State-of-the-art examples are showcased and signposts to more in-depth reviews about specific topics given for the specialist.

Gilmore, Ian S. [National Physical Laboratory, Teddington, Middlesex TW11 0LW (United Kingdom)] [National Physical Laboratory, Teddington, Middlesex TW11 0LW (United Kingdom)

2013-09-15

207

MIA-QSAR: a simple 2D image-based approach for quantitative structure activity relationship analysis  

NASA Astrophysics Data System (ADS)

An accessible and quite simple QSAR method, based on 2D image analysis, is reported. A case study is carried out in order to compare this model with a previously reported sophisticated methodology. A well known set of ( S)- N-[(1-ethyl-2-pyrrolidinyl)methyl]-6-methoxybenzamides, compounds with affinity to the dopamine D 2 receptor subtype, was divided in 40 calibration compounds and 18 test compounds and the descriptors were generated from pixels of 2D structures of each compound, which can be drawn with aid of any appropriate program. Bilinear (conventional) PLS was utilized as the regression method and leave-one-out cross-validation was performed using the NIPALS algorithm. The good predicted Q2 value obtained for the series of test compounds (0.58), together with the similar prediction quality obtained to other data sets (nAChR ligands, HIV protease inhibitors, COX-2 inhibitors and anxiolytic agents), suggests that the model is robust and seems to be as applicable as more complex methods.

Freitas, Matheus P.; Brown, Steven D.; Martins, José A.

2005-03-01

208

New generation CMOS 2D imager evaluation and qualification for semiconductor inspection applications  

NASA Astrophysics Data System (ADS)

Semiconductor fabrication process defect inspection industry is always driven by inspection resolution and through-put. With fabrication technology node advances to 2X ~1Xnm range, critical macro defect size approaches to typical CMOS camera pixel size range, therefore single pixel defect detection technology becomes more and more essential, which is fundamentally constrained by camera performance. A new evaluation model is presented here to specifically describe the camera performance for semiconductor machine vision applications, especially targeting at low image contrast high speed applications. Current mainline cameras and high-end OEM cameras are evaluated with this model. Camera performances are clearly differentiated among CMOS technology generations and vendors, which will facilitate application driven camera selection and operation optimization. The new challenges for CMOS detectors are discussed for semiconductor inspection applications.

Zhou, Wei; Hart, Darcy

2013-09-01

209

Use of 2D images of depth and integrated reflectivity to represent the severity of demineralization in cross-polarization optical coherence tomography.  

PubMed

Several studies have demonstrated the potential of cross-polarization optical coherence tomography (CP-OCT) to quantify the severity of early caries lesions (tooth decay) on tooth surfaces. The purpose of this study is to show that 2D images of the lesion depth and the integrated reflectivity can be used to accurately represent the severity of early lesions. Simulated early lesions of varying severity were produced on tooth samples using simulated lesion models. Methods were developed to convert the 3D CP-OCT images of the samples to 2D images of the lesion depth and lesion integrated reflectivity. Calculated lesion depths from OCT were compared with lesion depths measured from histological sections examined using polarized light microscopy. The 2D images of the lesion depth and integrated reflectivity are well suited for visualization of early demineralization. (© 2013 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim). PMID:24307350

Chan, Kenneth H; Chan, Andrew C; Fried, William A; Simon, Jacob C; Darling, Cynthia L; Fried, Daniel

2015-01-01

210

Enhancing LTW image encoder with perceptual coding and GPU-optimized 2D-DWT transform  

NASA Astrophysics Data System (ADS)

When optimizing a wavelet image coder, the two main targets are to (1) improve its rate-distortion (R/D) performance and (2) reduce the coding times. In general, the encoding engine is mainly responsible for achieving R/D performance. It is usually more complex than the decoding part. A large number of works about R/D or complexity optimizations can be found, but only a few tackle the problem of increasing R/D performance while reducing the computational cost at the same time, like Kakadu, an optimized version of JPEG2000. In this work we propose an optimization of the E_LTW encoder with the aim to increase its R/D performance through perceptual encoding techniques and reduce the encoding time by means of a graphics processing unit-optimized version of the two-dimensional discrete wavelet transform. The results show that in both performance dimensions, our enhanced encoder achieves good results compared with Kakadu and SPIHT encoders, achieving speedups of 6 times with respect to the original E_LTW encoder.

Martínez-Rach, Miguel O.; López-Granado, Otoniel; Galiano, Vicente; Migallón, Hector; Llor, Jesús; Malumbres, Manuel P.

2013-12-01

211

2D imaging in a 3D world: Observing sub-grain scale variations and secondary mineral precipitates in reacted pore networks  

NASA Astrophysics Data System (ADS)

Advancements in 3D imaging techniques and analysis methods, and easier access to benchtop 3D X-ray microscopes, have led to a proliferation of 3D imaging studies of chemical alterations within porous media. However, 2D imaging methods continue to offer complementary insights into processes controlling sub-grain scale variations in mineralogy and intragranular porosity that are often difficult to observe with 3D methods. For example, 2D imaging studies of mineral precipitation-induced changes in the pore network structure including detailed observations of distributions of secondary mineral precipitates can be coupled with 3D image analysis of a pore network to determine the pore properties required to infer permeability. In this work, the combined advantages of 2D and 3D imaging methods are highlighted through 3D X-ray Computed Microtomography (X-ray CT) and 2D Scanning Electron Microscopy (SEM) imaging of a reacted column experiment in the context of the Hanford, WA site and a sedimentary rock sample from the Alberta basin. Both samples were imaged using 3D X-ray CT imaging at a voxel resolution of 4 ?m and analyzed using 3DMA Rock to determine pore and throat size distributions as well as pore coordination numbers. Polished sections were then created from each sample and imaged using 2D SEM imaging with resolutions of 0.4 ?m for the reacted column and an order of magnitude larger for the sedimentary rock. 2D images were analyzed using an erosion dilation method to determine pore and throat size distributions that were then corrected using sample-specific bias correction factors. The permeability of each sample was predicted from pore network models informed with the 2D or 3D pore and throat size distributions and the coordination numbers determined from the 3D analysis. Differences in 2D and 3D image resolutions resulted in over- or under- estimating small pore throats and led to predicted permeabilities that differed by orders of magnitude. For both samples, higher resolution images resulted in over-estimating small pore throats and under-estimating expected permeability. While higher resolution images are generally favored, they may not improve predictions of permeability as they require additional processing to distinguish small flow-conducting pore throats from surface roughness features. While 3D imaging is required to determine the network coordination, 2D imaging is necessary to understand where secondary minerals precipitate within the pore network and to quantify sub-grain scale variations. These advantages are demonstrated through SEM imaging of polished sections from the reacted column experiment. 2D images revealed that secondary mineral precipitates occurred as a relatively uniform coating on grain surfaces, unrelated to mineralogy, pore size, or other factors. SEM images also revealed new observations of sub-grain scale variations that showed that Hanford sand grains have a high amount of intragranular porosity and mineral precipitates formed in intragranular regions. These observations, which are important to understanding the reactive system, could not have been made if 3D imaging was used exclusively.

Crandell, L. E.; Peters, C. A.; Um, W.; Jones, K. W.; Lindquist, W. B.

2012-12-01

212

Large area selective emitters/absorbers based on 2D tantalum photonic crystals for high-temperature energy applications  

NASA Astrophysics Data System (ADS)

We report highly selective emitters based on high-aspect ratio 2D photonic crystals (PhCs) fabricated on large area (2 inch diameter) polycrystalline tantalum substrates, suitable for high-temperature operation. As an example we present an optimized design for a selective emitter with a cut-off wavelength of 2?m, matched to the bandgap of an InGaAs PV cell, achieving a predicted spectral selectivity of 56.6% at 1200K. We present a fabrication route for these tantalum PhCs, based on standard microfabrication processes including deep reactive ion etch of tantalum by an SF6 based Bosch process, achieving high-aspect ratio cavities (< 8:1). Interference lithography was used to facilitate large area fabrication, maintaining both fabrication precision and uniformity, with a cavity diameter variation of less than 2% across the substrate. The fabricated tantalum PhCs exhibit strong enhancement of the emittance at wavelengths below cut-off wavelength, approaching that of blackbody, and a steep cut-off between high and low emittance spectral regions. Moreover, detailed simulations and numerical modeling show excellent agreement with experimental results. In addition, we propose a surface protective coating, which acts as a thermal barrier coating and diffusion inhibitor, and its conformal fabrication by atomic layer deposition.

Rinnerbauer, V.; Yeng, Y. X.; Senkevich, J. J.; Joannopoulos, J. D.; Solja?i?, M.; Celanovic, I.

2013-02-01

213

A Novel Assessment of Various Bio-Imaging Methods for Lung Tumor Detection and Treatment by using 4-D and 2-D CT Images  

PubMed Central

Lung Cancer is known as one of the most difficult cancer to cure, and the number of deaths that it causes generally increasing. A detection of the Lung Cancer in its early stage can be helpful for Medical treatment to limit the danger, but it is a challenging problem due to Cancer cell structure. Interpretation of Medical image is often difficult and time consuming, even for the experienced Physicians. The aid of image analysis Based on machine learning can make this process easier. This paper describes fully Automatic Decision Support system for Lung Cancer diagnostic from CT Lung images. Most traditional medical diagnosis systems are founded on huge quantity of training data and takes long processing time. However, on the occasion that very little volume of data is available, the traditional diagnosis systems derive defects such as larger error, Time complexity. Focused on the solution to this problem, a Medical Diagnosis System based on Hidden Markov Model (HMM) is presented. In this paper we describe a pre-processing stage involving some Noise removal techniques help to solve this problem, we preprocess an images (by Mean Error Square Filtering and Histogram analysis)obtained after scanning the Lung CT images. Secondly separate the lung areas from an image by a segmentation process (by Thresholding and region growing techniques). Finally we developed HMM for the classification of Cancer Nodule. Results are checked for 2D and 4D CT images. This automation process reduces the time complexity and increases the diagnosis confidence. PMID:23847454

Judice A., Antony; Geetha, Dr. K. Parimala

2013-01-01

214

A Novel Assessment of Various Bio-Imaging Methods for Lung Tumor Detection and Treatment by using 4-D and 2-D CT Images.  

PubMed

Lung Cancer is known as one of the most difficult cancer to cure, and the number of deaths that it causes generally increasing. A detection of the Lung Cancer in its early stage can be helpful for Medical treatment to limit the danger, but it is a challenging problem due to Cancer cell structure. Interpretation of Medical image is often difficult and time consuming, even for the experienced Physicians. The aid of image analysis Based on machine learning can make this process easier. This paper describes fully Automatic Decision Support system for Lung Cancer diagnostic from CT Lung images. Most traditional medical diagnosis systems are founded on huge quantity of training data and takes long processing time. However, on the occasion that very little volume of data is available, the traditional diagnosis systems derive defects such as larger error, Time complexity. Focused on the solution to this problem, a Medical Diagnosis System based on Hidden Markov Model (HMM) is presented. In this paper we describe a pre-processing stage involving some Noise removal techniques help to solve this problem, we preprocess an images (by Mean Error Square Filtering and Histogram analysis)obtained after scanning the Lung CT images. Secondly separate the lung areas from an image by a segmentation process (by Thresholding and region growing techniques). Finally we developed HMM for the classification of Cancer Nodule. Results are checked for 2D and 4D CT images. This automation process reduces the time complexity and increases the diagnosis confidence. PMID:23847454

Judice A, Antony; Geetha, Dr K Parimala

2013-06-01

215

A novel approach of computer-aided detection of focal ground-glass opacity in 2D lung CT images  

NASA Astrophysics Data System (ADS)

Focal Ground-Glass Opacity (fGGO) plays an important role in diagnose of lung cancers. This paper proposes a novel approach for detecting fGGOs in 2D lung CT images. The approach consists of two stages: extracting regions of interests (ROIs) and labeling each ROI as fGGO or non-fGGO. In the first stage, we use the techniques of Otsu thresholding and mathematical morphology to segment lung parenchyma from lung CT images and extract ROIs in lung parenchyma. In the second stage, a Bayesian classifier is constructed based on the Gaussian mixture Modeling (GMM) of the distribution of visual features of fGGOs to fulfill ROI identification. The parameters in the classifier are estimated from training data by the discriminative learning method of Max-Min posterior Pseudo-probabilities (MMP). A genetic algorithm is further developed to select compact and discriminative features for the classifier. We evaluated the proposed fGGO detection approach through 5-fold cross-validation experiments on a set of 69 lung CT scans that contain 70 fGGOs. The proposed approach achieves the detection sensitivity of 85.7% at the false positive rate of 2.5 per scan, which proves its effectiveness. We also demonstrate the usefulness of our genetic algorithm based feature selection method and MMP discriminative learning method through comparing them with without-selection strategy and Support Vector Machines (SVMs), respectively, in the experiments.

Li, Song; Liu, Xiabi; Yang, Ali; Pang, Kunpeng; Zhou, Chunwu; Zhao, Xinming; Zhao, Yanfeng

2013-02-01

216

WASI-2D: A software tool for regionally optimized analysis of imaging spectrometer data from deep and shallow waters  

NASA Astrophysics Data System (ADS)

An image processing software has been developed which allows quantitative analysis of multi- and hyperspectral data from oceanic, coastal and inland waters. It has been implemented into the Water Colour Simulator WASI, which is a tool for the simulation and analysis of optical properties and light field parameters of deep and shallow waters. The new module WASI-2D can import atmospherically corrected images from airborne sensors and satellite instruments in various data formats and units like remote sensing reflectance or radiance. It can be easily adapted by the user to different sensors and to optical properties of the studied area. Data analysis is done by inverse modelling using established analytical models. The bio-optical model of the water column accounts for gelbstoff (coloured dissolved organic matter, CDOM), detritus, and mixtures of up to 6 phytoplankton classes and 2 spectrally different types of suspended matter. The reflectance of the sea floor is treated as sum of up to 6 substrate types. An analytic model of downwelling irradiance allows wavelength dependent modelling of sun glint and sky glint at the water surface. The provided database covers the spectral range from 350 to 1000 nm in 1 nm intervals. It can be exchanged easily to represent the optical properties of water constituents, bottom types and the atmosphere of the studied area.

Gege, Peter

2014-01-01

217

Imaging 2D structures by the CSAMT method: application to the Pantano di S. Gregorio Magno faulted basin (Southern Italy)  

NASA Astrophysics Data System (ADS)

A controlled source audiofrequency magnetotelluric (CSAMT) survey has been undertaken in the Pantano di San Gregorio Magno faulted basin, an earthquake prone area of Southern Apennines in Italy. A dataset from 11 soundings, distributed along a nearly N-S 780 m long profile, was acquired in the basin's easternmost area, where the fewest data are available as to the faulting shallow features. A preliminary skew analysis allowed a prevailing 2D nature of the dataset to be ascertained. Then, using a single-site multi-frequency approach, Dantzig's simplex algorithm was introduced for the first time to estimate the CSAMT decomposition parameters. The simplex algorithm, freely available online, proved to be fast and efficient. By this approach, the TM and TE mode field diagrams were obtained and a N35°W ± 10° 2D strike mean direction was estimated along the profile, in substantial agreement with the fault traces within the basin. A 2D inversion of the apparent resistivity and phase curves at seven almost noise-free sites distributed along the central portion of the profile was finally elaborated, reinforced by a sensitivity analysis, which allowed the best resolved portion of the model to be imaged from the first few meters of depth down to a mean depth of 300 m b.g.l. From the inverted section, the following features have been outlined: (i) a cover layer with resistivity in the range 3-30 ? m ascribed to the Quaternary lacustrine clayey deposits filling the basin, down to an average depth of about 35 m b.g.l., underlain by a structure with resistivity over 50 ? m up to about 600 ? m, ascribed to the Mesozoic carbonate bedrock; (ii) a system of two normal faults within the carbonate basement, extending down to the maximum best resolved depth of the order of 300 m b.g.l.; (iii) two wedge-shaped domains separating the opposite blocks of the faults with resistivity ranging between 30 ? m and 50 ? m and horizontal extent of the order of some tens of metres, likely filled with lacustrine sediments and embedded fine gravels.

Troiano, Antonio; Di Giuseppe, Maria Giulia; Petrillo, Zaccaria; Patella, Domenico

2009-06-01

218

Robust initialization of 2D-3D image registration using the projection-slice theorem and phase correlation  

SciTech Connect

Purpose: The image registration literature comprises many methods for 2D-3D registration for which accuracy has been established in a variety of applications. However, clinical application is limited by a small capture range. Initial offsets outside the capture range of a registration method will not converge to a successful registration. Previously reported capture ranges, defined as the 95% success range, are in the order of 4-11 mm mean target registration error. In this article, a relatively computationally inexpensive and robust estimation method is proposed with the objective to enlarge the capture range. Methods: The method uses the projection-slice theorem in combination with phase correlation in order to estimate the transform parameters, which provides an initialization of the subsequent registration procedure. Results: The feasibility of the method was evaluated by experiments using digitally reconstructed radiographs generated from in vivo 3D-RX data. With these experiments it was shown that the projection-slice theorem provides successful estimates of the rotational transform parameters for perspective projections and in case of translational offsets. The method was further tested on ex vivo ovine x-ray data. In 95% of the cases, the method yielded successful estimates for initial mean target registration errors up to 19.5 mm. Finally, the method was evaluated as an initialization method for an intensity-based 2D-3D registration method. The uninitialized and initialized registration experiments had success rates of 28.8% and 68.6%, respectively. Conclusions: The authors have shown that the initialization method based on the projection-slice theorem and phase correlation yields adequate initializations for existing registration methods, thereby substantially enlarging the capture range of these methods.

Bom, M. J. van der; Bartels, L. W.; Gounis, M. J.; Homan, R.; Timmer, J.; Viergever, M. A.; Pluim, J. P. W. [Image Sciences Institute, University Medical Center Utrecht, Q0S.459, P.O. Box 85500, 3508 GA Utrecht (Netherlands); Department of Radiology, University of Massachusetts Medical School, 55 Lake Avenue North, H2-573, Worcester, Massachusetts 01655 (United States); Philips Healthcare, X-Ray Predevelopment, P.O. Box 10000, 5680 DA Best (Netherlands); Image Sciences Institute, University Medical Center Utrecht, Q0S.459, P.O. Box 85500, 3508 GA Utrecht (Netherlands)

2010-04-15

219

Robust 3D-2D image registration: application to spine interventions and vertebral labeling in the presence of anatomical deformation  

NASA Astrophysics Data System (ADS)

We present a framework for robustly estimating registration between a 3D volume image and a 2D projection image and evaluate its precision and robustness in spine interventions for vertebral localization in the presence of anatomical deformation. The framework employs a normalized gradient information similarity metric and multi-start covariance matrix adaptation evolution strategy optimization with local-restarts, which provided improved robustness against deformation and content mismatch. The parallelized implementation allowed orders-of-magnitude acceleration in computation time and improved the robustness of registration via multi-start global optimization. Experiments involved a cadaver specimen and two CT datasets (supine and prone) and 36 C-arm fluoroscopy images acquired with the specimen in four positions (supine, prone, supine with lordosis, prone with kyphosis), three regions (thoracic, abdominal, and lumbar), and three levels of geometric magnification (1.7, 2.0, 2.4). Registration accuracy was evaluated in terms of projection distance error (PDE) between the estimated and true target points in the projection image, including 14?400 random trials (200 trials on the 72 registration scenarios) with initialization error up to ±200 mm and ±10°. The resulting median PDE was better than 0.1 mm in all cases, depending somewhat on the resolution of input CT and fluoroscopy images. The cadaver experiments illustrated the tradeoff between robustness and computation time, yielding a success rate of 99.993% in vertebral labeling (with ‘success’ defined as PDE <5 mm) using 1,718?664 ± 96?582 function evaluations computed in 54.0 ± 3.5 s on a mid-range GPU (nVidia, GeForce GTX690). Parameters yielding a faster search (e.g., fewer multi-starts) reduced robustness under conditions of large deformation and poor initialization (99.535% success for the same data registered in 13.1 s), but given good initialization (e.g., ±5 mm, assuming a robust initial run) the same registration could be solved with 99.993% success in 6.3 s. The ability to register CT to fluoroscopy in a manner robust to patient deformation could be valuable in applications such as radiation therapy, interventional radiology, and an assistant to target localization (e.g., vertebral labeling) in image-guided spine surgery.

Otake, Yoshito; Wang, Adam S.; Webster Stayman, J.; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Khanna, A. Jay; Gokaslan, Ziya L.; Siewerdsen, Jeffrey H.

2013-12-01

220

Robust 3D-2D image registration: application to spine interventions and vertebral labeling in the presence of anatomical deformation.  

PubMed

We present a framework for robustly estimating registration between a 3D volume image and a 2D projection image and evaluate its precision and robustness in spine interventions for vertebral localization in the presence of anatomical deformation. The framework employs a normalized gradient information similarity metric and multi-start covariance matrix adaptation evolution strategy optimization with local-restarts, which provided improved robustness against deformation and content mismatch. The parallelized implementation allowed orders-of-magnitude acceleration in computation time and improved the robustness of registration via multi-start global optimization. Experiments involved a cadaver specimen and two CT datasets (supine and prone) and 36 C-arm fluoroscopy images acquired with the specimen in four positions (supine, prone, supine with lordosis, prone with kyphosis), three regions (thoracic, abdominal, and lumbar), and three levels of geometric magnification (1.7, 2.0, 2.4). Registration accuracy was evaluated in terms of projection distance error (PDE) between the estimated and true target points in the projection image, including 14 400 random trials (200 trials on the 72 registration scenarios) with initialization error up to ±200 mm and ±10°. The resulting median PDE was better than 0.1 mm in all cases, depending somewhat on the resolution of input CT and fluoroscopy images. The cadaver experiments illustrated the tradeoff between robustness and computation time, yielding a success rate of 99.993% in vertebral labeling (with 'success' defined as PDE <5 mm) using 1,718 664 ± 96 582 function evaluations computed in 54.0 ± 3.5 s on a mid-range GPU (nVidia, GeForce GTX690). Parameters yielding a faster search (e.g., fewer multi-starts) reduced robustness under conditions of large deformation and poor initialization (99.535% success for the same data registered in 13.1 s), but given good initialization (e.g., ±5 mm, assuming a robust initial run) the same registration could be solved with 99.993% success in 6.3 s. The ability to register CT to fluoroscopy in a manner robust to patient deformation could be valuable in applications such as radiation therapy, interventional radiology, and an assistant to target localization (e.g., vertebral labeling) in image-guided spine surgery. PMID:24246386

Otake, Yoshito; Wang, Adam S; Webster Stayman, J; Uneri, Ali; Kleinszig, Gerhard; Vogt, Sebastian; Khanna, A Jay; Gokaslan, Ziya L; Siewerdsen, Jeffrey H

2013-12-01

221

A Rapid and Efficient 2D/3D Nuclear Segmentation Method for Analysis of Early Mouse Embryo and Stem Cell Image Data  

PubMed Central

Summary Segmentation is a fundamental problem that dominates the success of microscopic image analysis. In almost 25 years of cell detection software development, there is still no single piece of commercial software that works well in practice when applied to early mouse embryo or stem cell image data. To address this need, we developed MINS (modular interactive nuclear segmentation) as a MATLAB/C++-based segmentation tool tailored for counting cells and fluorescent intensity measurements of 2D and 3D image data. Our aim was to develop a tool that is accurate and efficient yet straightforward and user friendly. The MINS pipeline comprises three major cascaded modules: detection, segmentation, and cell position classification. An extensive evaluation of MINS on both 2D and 3D images, and comparison to related tools, reveals improvements in segmentation accuracy and usability. Thus, its accuracy and ease of use will allow MINS to be implemented for routine single-cell-level image analyses. PMID:24672759

Lou, Xinghua; Kang, Minjung; Xenopoulos, Panagiotis; Muñoz-Descalzo, Silvia; Hadjantonakis, Anna-Katerina

2014-01-01

222

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

223

Efficient Decoding of 2D Structured Illumination with Linear Phase Stepping in X-Ray Phase Contrast and Dark-Field Imaging  

PubMed Central

The ability to map the phase distribution and lateral coherence of an x-ray wavefront offers the potential for imaging the human body through phase contrast, without the need to deposit significant radiation energy. The classic means to achieve this goal is structured illumination, in which a periodic intensity modulation is introduced into the image, and changes in the phase distribution of the wavefront are detected as distortions of the modulation pattern. Two-dimensional periodic patterns are needed to fully characterize a transverse wavefront. Traditionally, the information in a 2D pattern is retrieved at high resolution by acquiring multiple images while shifting the pattern over a 2D matrix of positions. Here we describe a method to decode 2D periodic patterns with single-axis phase stepping, without either a loss of information or increasing the number of sampling steps. The method is created to reduce the instrumentation complexity of high-resolution 2D wavefront sensing in general. It is demonstrated with motionless electromagnetic phase stepping and a flexible processing algorithm in x-ray dark-field and phase contrast imaging. PMID:24489853

Harmon, Katherine J.; Bennett, Eric E.; Gomella, Andrew A.; Wen, Han

2014-01-01

224

A Novel Method to Improve Image Quality for 2-D Small Animal PET Reconstruction by Correcting a Monte Carlo-Simulated System Matrix Using an Artificial Neural Network  

Microsoft Academic Search

The aim of this study was to improve image quality of statistical reconstruction by using the 2-D system matrix (SM) trained with an artificial neural network (ANN). For training the ANN SM (SMANN), the inputs of ANN, the digital images, were generated by scanning the mini-deluxe cold spot phantom at ten different orientations using an optical scanner (resolution: 0.01 mm\\/pixel).

Kuan-Hao Su; Liang-Chih Wu; Jih-Shian Lee; Ren-Shyan Liu; Jyh-Cheng Chen

2009-01-01

225

Automatic localization of target vertebrae in spine surgery using fast CT-to-fluoroscopy (3D-2D) image registration  

NASA Astrophysics Data System (ADS)

Localization of target vertebrae is an essential step in minimally invasive spine surgery, with conventional methods relying on "level counting" - i.e., manual counting of vertebrae under fluoroscopy starting from readily identifiable anatomy (e.g., the sacrum). The approach requires an undesirable level of radiation, time, and is prone to counting errors due to the similar appearance of vertebrae in projection images; wrong-level surgery occurs in 1 of every ~3000 cases. This paper proposes a method to automatically localize target vertebrae in x-ray projections using 3D-2D registration between preoperative CT (in which vertebrae are preoperatively labeled) and intraoperative fluoroscopy. The registration uses an intensity-based approach with a gradient-based similarity metric and the CMA-ES algorithm for optimization. Digitally reconstructed radiographs (DRRs) and a robust similarity metric are computed on GPU to accelerate the process. Evaluation in clinical CT data included 5,000 PA and LAT projections randomly perturbed to simulate human variability in setup of mobile intraoperative C-arm. The method demonstrated 100% success for PA view (projection error: 0.42mm) and 99.8% success for LAT view (projection error: 0.37mm). Initial implementation on GPU provided automatic target localization within about 3 sec, with further improvement underway via multi-GPU. The ability to automatically label vertebrae in fluoroscopy promises to streamline surgical workflow, improve patient safety, and reduce wrong-site surgeries, especially in large patients for whom manual methods are time consuming and error prone.

Otake, Y.; Schafer, S.; Stayman, J. W.; Zbijewski, W.; Kleinszig, G.; Graumann, R.; Khanna, A. J.; Siewerdsen, J. H.

2012-02-01

226

2D segmentation of intervertebral discs and its degree of degeneration from T2-weighted magnetic resonance images  

NASA Astrophysics Data System (ADS)

Low back pain (LBP) is a disorder suffered by a large population around the world. A key factor causing this illness is Intervertebral Disc (IVD) degeneration, whose early diagnosis could help in preventing this widespread condition. Clinicians base their diagnosis on visual inspection of 2D slices of Magnetic Resonance (MR) images, which is subject to large interobserver variability. In this work, an automatic classification method is presented, which provides the Pfirrmann degree of degeneration from a mid-sagittal MR slice. The proposed method utilizes Active Contour Models, with a new geometrical energy, to achieve an initial segmentation, which is further improved using fuzzy C-means. Then, IVDs are classified according to their degree of degeneration. This classification is attained by employing Adaboost on five specific features: the mean and the variance of the probability map of the nucleus using two different approaches and the eccentricity of the fitting ellipse to the contour of the IVD. The classification method was evaluated using a cohort of 150 intervertebral discs assessed by three experts, resulting in a mean specificity (93%) and sensitivity (83%) similar to the one provided by every expert with respect to the most voted value. The segmentation accuracy was evaluated using the Dice Similarity Index (DSI) and Root Mean Square Error (RMSE) of the point-to-contour distance. The mean DSI ± 2 standard deviation was 91:7% ±5:6%, the mean RMSE was 0:82mm and the 95 percentile was 1:36mm. These results were found accurate when compared to the state-of-the-art.

Castro-Mateos, Isaac; Pozo, José Maria; Lazary, Aron; Frangi, Alejandro F.

2014-03-01

227

Joint Probability of Shape and Image Similarities to Retrieve 2D TRUS-MR Slice Correspondence for Prostate Biopsy  

E-print Network

for Prostate Biopsy J. Mitra1,2, S. Ghose1,2, D. Sidib´e1, R. Mart´i2, A. Oliver2, X. Llad´o2, J. C. Vilanova3 Magnetic Resonance (MR) slice from a pre-acquired MR prostate volume that closely corresponds to the 2D axial Transrectal Ultrasound (TRUS) slice obtained during prostate biopsy. The method combines both

Paris-Sud XI, Université de

228

Significant acceleration of 2D-3D registration-based fusion of ultrasound and x-ray images by mesh-based DRR rendering  

NASA Astrophysics Data System (ADS)

For transcatheter-based minimally invasive procedures in structural heart disease ultrasound and X-ray are the two enabling imaging modalities. A live fusion of both real-time modalities can potentially improve the workflow and the catheter navigation by combining the excellent instrument imaging of X-ray with the high-quality soft tissue imaging of ultrasound. A recently published approach to fuse X-ray fluoroscopy with trans-esophageal echo (TEE) registers the ultrasound probe to X-ray images by a 2D-3D registration method which inherently provides a registration of ultrasound images to X-ray images. In this paper, we significantly accelerate the 2D-3D registration method in this context. The main novelty is to generate the projection images (DRR) of the 3D object not via volume ray-casting but instead via a fast rendering of triangular meshes. This is possible, because in the setting for TEE/X-ray fusion the 3D geometry of the ultrasound probe is known in advance and their main components can be described by triangular meshes. We show that the new approach can achieve a speedup factor up to 65 and does not affect the registration accuracy when used in conjunction with the gradient correlation similarity measure. The improvement is independent of the underlying registration optimizer. Based on the results, a TEE/X-ray fusion could be performed with a higher frame rate and a shorter time lag towards real-time registration performance. The approach could potentially accelerate other applications of 2D-3D registrations, e.g. the registration of implant models with X-ray images.

Kaiser, Markus; John, Matthias; Borsdorf, Anja; Mountney, Peter; Ionasec, Razvan; Nöttling, Alois; Kiefer, Philipp; Seeburger, Jörg; Neumuth, Thomas

2013-03-01

229

Textural analyses of carbon fiber materials by 2D-FFT of complex images obtained by high frequency eddy current imaging (HF-ECI)  

NASA Astrophysics Data System (ADS)

Carbon fiber based materials are used in many lightweight applications in aeronautical, automotive, machine and civil engineering application. By the increasing automation in the production process of CFRP laminates a manual optical inspection of each resin transfer molding (RTM) layer is not practicable. Due to the limitation to surface inspection, the quality parameters of multilayer 3 dimensional materials cannot be observed by optical systems. The Imaging Eddy- Current (EC) NDT is the only suitable inspection method for non-resin materials in the textile state that allows an inspection of surface and hidden layers in parallel. The HF-ECI method has the capability to measure layer displacements (misaligned angle orientations) and gap sizes in a multilayer carbon fiber structure. EC technique uses the variation of the electrical conductivity of carbon based materials to obtain material properties. Beside the determination of textural parameters like layer orientation and gap sizes between rovings, the detection of foreign polymer particles, fuzzy balls or visualization of undulations can be done by the method. For all of these typical parameters an imaging classification process chain based on a high resolving directional ECimaging device named EddyCus® MPECS and a 2D-FFT with adapted preprocessing algorithms are developed.

Schulze, Martin H.; Heuer, Henning

2012-04-01

230

Effects of Temperature on First-Excited-State Energy of the Strong Coupling Magnetopolaron in 2D RbCl Parabolic Quantum Dots  

NASA Astrophysics Data System (ADS)

We study the effects of external fields that are present in nanostructures and can trap particles and manipulate their quantum states. To obtain the effects of temperature on the strong coupling magnetopolaron's first-excited-state energy (FESE) and transition frequency (TF), we use the Lee-Low-Pines unitary transformation (LLPUT) and linear combination operation (LCO) methods. Numerical results, performed in the 2D RbCl parabolic quantum dot (QD), show that the magnetopolaron's FESE and TF (MFESETF) increase with increasing the effective confinement strength and cyclotron frequency (CF) of the magnetic field and temperature.

Cai, Chun-Yu; Zhao, Cui-Lan; Xiao, Jing-Lin

2015-02-01

231

The 2D versus 3D imaging trade-off: The impact of over- or under-estimating small throats for simulating permeability in porous media  

NASA Astrophysics Data System (ADS)

Geochemical reactions in the subsurface can alter the porosity and permeability of a porous medium through mineral precipitation and dissolution. While effects on porosity are relatively well understood, changes in permeability are more difficult to estimate. In this work, pore-network modeling is used to estimate the permeability of a porous medium using pore and throat size distributions. These distributions can be determined from 2D Scanning Electron Microscopy (SEM) images of thin sections or from 3D X-ray Computed Tomography (CT) images of small cores. Each method has unique advantages as well as unique sources of error. 3D CT imaging has the advantage of reconstructing a 3D pore network without the inherent geometry-based biases of 2D images but is limited by resolutions around 1 ?m. 2D SEM imaging has the advantage of higher resolution, and the ability to examine sub-grain scale variations in porosity and mineralogy, but is limited by the small size of the sample of pores that are quantified. A pore network model was created to estimate flow permeability in a sand-packed experimental column investigating reaction of sediments with caustic radioactive tank wastes in the context of the Hanford, WA site. Before, periodically during, and after reaction, 3D images of the porous medium in the column were produced using the X2B beam line facility at the National Synchrotron Light Source (NSLS) at Brookhaven National Lab. These images were interpreted using 3DMA-Rock to characterize the pore and throat size distributions. After completion of the experiment, the column was sectioned and imaged using 2D SEM in backscattered electron mode. The 2D images were interpreted using erosion-dilation to estimate the pore and throat size distributions. A bias correction was determined by comparison with the 3D image data. A special image processing method was developed to infer the pore space before reaction by digitally removing the precipitate. The different sets of pore property distributions were used to generate different network flow models, to examine permeability alterations due to reaction-induced changes in throat sizes. 3D CT images, limited to a resolution of approximately 4 microns, miss small throats present at grain-to-grain contacts. The higher resolution of SEM images captures small throats between grains, however grain surface roughness and other small scale features may be misinterpreted. Precise determination of throat distributions requires careful thresholding to distinguish flow-conducting throats from throats leading to pores that are really just surface roughness. Using the pore network model, the sensitivity of permeability to the throat size roughness threshold was evaluated. Permeabilities calculated from the 2D and 3D pore and throat size distributions are compared to determine the impact of the lower resolution 3D images missing small throats.

Peters, C. A.; Crandell, L. E.; Um, W.; Jones, K. W.; Lindquist, W. B.

2011-12-01

232

Analysis of high resolution 2-D images of the m/n=2/1 tearing mode in KSTAR RMP experiments  

NASA Astrophysics Data System (ADS)

In the 2011 KSTAR campaign, the m/n=2/1 tearing mode has often been observed in plasmas with externally applied static n=1 Resonant Magnetic Perturbation (RMP) fields. It is generally believed that the RMP can induce tearing of flux surfaces via the so-called mode penetration mechanism [1]: (1) the RMP slows the plasma rotation down to the resonance condition, (2) the plasma shielding current is minimized, and (3) the RMP fields penetrate into the plasma, tearing the flux surfaces. This scenario of tearing mode generation induced by RMP is consistent with the observed changes of the toroidal velocity profile and the appearance of tearing mode structures as reconstructed from 2-D electron cyclotron emission (ECE) images. In addition, the detailed 2-D ECE images of the tearing mode enabled a straightforward estimation of the delta prime, which is a critical parameter for understanding the tearing physics.[4pt] [1] F.L. Waelbroeck, Nucl. Fusion 49 (2009).

Choi, Minjun; Yun, G. S.; Lee, W.; Park, H. K.; Domier, C. W.; Luhmann, N. C., Jr.; Donné, A. J. H.; Lee, S. G.

2012-10-01

233

Primitive-based 3D structure inference from a single 2D image for insect modeling: Towards an electronic field guide for insect identification  

Microsoft Academic Search

3D insect models are useful to overcome viewing angle variations and self-occlusions in computer-assisted insect taxonomy for electronic field guides. The acquisition of 3D information is, however, unreliable due to the flexibility and small size of the insect bodies. This paper explores how to infer 3D insect models from a single 2D insect image, which will assist both insect description

Xiaozheng Zhang; Yongsheng Gao; Terry Caelli

2010-01-01

234

Bayesian estimation of 2-D P-velocity models from active seismic arrival time data: imaging of the shallow structure of Mt Vesuvius (Southern Italy)  

Microsoft Academic Search

A multi-2-D non linear traveltime tomography of the shallow (3-4 km deep) structure of Mt Vesuvius volcano was performed. Data have been collected during two recent active seismic experiments using a total of 17 on-land shots and about 140 three-component digital seismographs. A newly developed technique for imaging the volcano velocity structure has been applied, based on an adaptive model

A. Zollo; L. D'Auria; R. De Matteis; A. Herrero; J. Virieux; P. Gasparini

2002-01-01

235

Characteristics of Spondylotic Myelopathy on 3D Driven-Equilibrium Fast Spin Echo and 2D Fast Spin Echo Magnetic Resonance Imaging: A Retrospective Cross-Sectional Study  

PubMed Central

In patients with spinal stenosis, magnetic resonance imaging of the cervical spine can be improved by using 3D driven-equilibrium fast spin echo sequences to provide a high-resolution assessment of osseous and ligamentous structures. However, it is not yet clear whether 3D driven-equilibrium fast spin echo sequences adequately evaluate the spinal cord itself. As a result, they are generally supplemented by additional 2D fast spin echo sequences, adding time to the examination and potential discomfort to the patient. Here we investigate the hypothesis that in patients with spinal stenosis and spondylotic myelopathy, 3D driven-equilibrium fast spin echo sequences can characterize cord lesions equally well as 2D fast spin echo sequences. We performed a retrospective analysis of 30 adult patients with spondylotic myelopathy who had been examined with both 3D driven-equilibrium fast spin echo sequences and 2D fast spin echo sequences at the same scanning session. The two sequences were inspected separately for each patient, and visible cord lesions were manually traced. We found no significant differences between 3D driven-equilibrium fast spin echo and 2D fast spin echo sequences in the mean number, mean area, or mean transverse dimensions of spondylotic cord lesions. Nevertheless, the mean contrast-to-noise ratio of cord lesions was decreased on 3D driven-equilibrium fast spin echo sequences compared to 2D fast spin echo sequences. These findings suggest that 3D driven-equilibrium fast spin echo sequences do not need supplemental 2D fast spin echo sequences for the diagnosis of spondylotic myelopathy, but they may be less well suited for quantitative signal measurements in the spinal cord. PMID:25025170

Abdulhadi, Mike A.; Perno, Joseph R.; Melhem, Elias R.; Nucifora, Paolo G. P.

2014-01-01

236

2D multi-parameter elastic seismic imaging by frequency-domain L1-norm full waveform inversion  

NASA Astrophysics Data System (ADS)

Full waveform inversion (FWI) is becoming a powerful and efficient tool to derive high-resolution quantitative models of the subsurface. In the frequency-domain, computationally efficient FWI algorithms can be designed for wide-aperture acquisition geometries by limiting inversion to few discrete frequencies. However, FWI remains an ill-posed and highly non-linear data-fitting procedure that is sensitive to noise, inaccuracies of the starting model and definition of multiparameter classes. The footprint of the noise in seismic imaging is conventionally mitigated by stacking highly redundant multifold data. However, when the data redundancy is decimated in the framework of efficient frequency-domain FWI, it is essential to assess the sensitivity of the inversion to noise. The impact of the noise in FWI, when applied to decimated data sets, has been marginally illustrated in the past and least-squares minimisation has remained the most popular approach. We investigate in this study the sensitivity of frequency-domain elastic FWI to noise for realistic onshore and offshore synthetic data sets contaminated by ambient random white noise. Four minimisation functionals are assessed in the framework of frequency domain FWI of decimated data: the classical least-square norm (L2), the least-absolute-values norm (L1), and some combinations of both (the Huber and the so-called Hybrid criteria). These functionals are implemented in a massively-parallel, 2D elastic frequency-domain FWI algorithm. A two-level hierarchical algorithm is implemented to mitigate the non-linearity of the inversion in complex environments. The first outer level consists of successive inversions of frequency groups of increasing high-frequency content. This level defines a multi-scale approach while preserving some data redundancy by means of simultaneous inversion of multiple frequencies. The second inner level used complex-valued frequencies for data preconditioning. This preconditioning controls the amount of the data involved in the inversion from the first-arrival time and allows us to mitigate the weight of the complex late arrivals during the first iterations of the inversion. We applied our FWI approach to the SEG/EAGE overthrust model and the shallow-water Valhall model which is representative of oil and gas fields in North Sea. Results show that the L1 norm provides the most reliable models for both applications, even when only few discrete frequencies are used in the inversion and outliers pollute the data. The L2 norm can provide reliable results in the presence of uniform white noise only if the data redundancy is increased by refining the frequency sampling interval in the inversion, at the expense of the computational efficiency. The Huber and the Hybrid criteria are shown to be sensitive to a threshold, which controls the transition between the L1 and L2 behaviours, and which requires tedious trial-and-error investigations for reliable estimation. We show that the L1 norm provides a robust alternative to the classical approach based on the L2 norm for the inversion of decimated data sets in the framework of efficient frequency-domain FWI.

Brossier, Romain; Operto, Stéphane; Virieux, Jean

2010-05-01

237

A robust cell counting approach based on a normalized 2D cross-correlation scheme for in-line holographic images.  

PubMed

To achieve the important aims of identifying and marking disease progression, cell counting is crucial for various biological and medical procedures, especially in a Point-Of-Care (POC) setting. In contrast to the conventional manual method of counting cells, a software-based approach provides improved reliability, faster speeds, and greater ease of use. We present a novel software-based approach to count in-line holographic cell images using the calculation of a normalized 2D cross-correlation. This enables fast, computationally-efficient pattern matching between a set of cell library images and the test image. Our evaluation results show that the proposed system is capable of quickly counting cells whilst reliably and accurately following human counting capability. Our novel approach is 5760 times faster than manual counting and provides at least 68% improved accuracy compared to other image processing algorithms. PMID:23839256

Ra, Ho-Kyeong; Kim, Hyungseok; Yoon, Hee Jung; Son, Sang Hyuk; Park, Taejoon; Moon, Sangjun

2013-09-01

238

Efficient Training of Convolutional Deep Belief Networks in the Frequency Domain for Application to High-Resolution 2D and 3D Images.  

PubMed

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

Brosch, Tom; Tam, Roger

2015-01-01

239

2D Perovskite Nanosheets with Thermally-Stable High-? Response: A New Platform for High-Temperature Capacitors.  

PubMed

We investigated high-temperature dielectric responses of high-? perovskite nanosheet (Ca2Nb3O10), an important material platform for postgraphene technology and ultrascale electronic devices. Through in situ characterizations using conducting atomic force microscopy, we found a robust high-temperature property of Ca2Nb3O10 nanosheet even in a monolayer form (?2 nm). Furthermore, layer-by-layer assembled nanocapacitors retained both size-free high-?r characteristic (?200) and high insulation resistance (?1 × 10(-7) A/cm(2)) at high temperatures up to 250 °C. The simultaneous improvement of ?r and thermal stability in high-? nanodielectrics is of critical technological importance, and perovskite nanosheet has great potential for a rational design and construction of high-temperature capacitors. PMID:25372940

Kim, Yoon-Hyun; Kim, Hyung-Jun; Osada, Minoru; Li, Bao-Wen; Ebina, Yasuo; Sasaki, Takayoshi

2014-11-26

240

Stream Temperature Estimation From Thermal Infrared Images  

NASA Astrophysics Data System (ADS)

Stream temperature is an important water quality indicator in the Pacific Northwest where endangered fish populations are sensitive to elevated water temperature. Cold water refugia are essential for the survival of threatened salmon when events such as the removal of riparian vegetation result in elevated stream temperatures. Regional assessment of stream temperatures is limited by sparse sampling of temperatures in both space and time. If critical watersheds are to be properly managed it is necessary to have spatially extensive temperature measurements of known accuracy. Remotely sensed thermal infrared (TIR) imagery can be used to derive spatially distributed estimates of the skin temperature (top 100 nm) of streams. TIR imagery has long been used to estimate skin temperatures of the ocean, where split-window techniques have been used to compensate for atmospheric affects. Streams are a more complex environment because 1) most are unresolved in typical TIR images, and 2) the near-bank environment of stream corridors may consist of tall trees or hot rocks and soils that irradiate the stream surface. As well as compensating for atmospheric effects, key problems to solve in estimating stream temperatures include both subpixel unmixing and multiple scattering. Additionally, fine resolution characteristics of the stream surface such as evaporative cooling due to wind, and water surface roughness, will effect measurements of radiant skin temperatures with TIR devices. We apply these corrections across the Green River and Yakima River watersheds in Washington State to assess the accuracy of remotely sensed stream surface temperature estimates made using fine resolution TIR imagery from a ground-based sensor (FLIR), medium resolution data from the airborne MASTER sensor, and coarse-resolution data from the Terra-ASTER satellite. We use linear spectral mixture analysis to isolate the fraction of land-leaving radiance originating from unresolved streams. To compensate the data for atmospheric effects we combine radiosonde profiles with a physically based radiative transfer model (MODTRAN) and an in-scene relative correction adapted from the ISAC algorithm. Laboratory values for water emissivities are used as a baseline estimate of stream emissivities. Emitted radiance reflected by trees in the stream near-bank environment is estimated from the height and canopy temperature, using a radiosity model.

Handcock, R. N.; Kay, J. E.; Gillespie, A.; Naveh, N.; Cherkauer, K. A.; Burges, S. J.; Booth, D. B.

2001-12-01

241

Effects of Precipitation on Ocean Mixed-Layer Temperature and Salinity as Simulated in a 2-D Coupled Ocean-Cloud Resolving Atmosphere Model  

NASA Technical Reports Server (NTRS)

A two-dimensional coupled ocean-cloud resolving atmosphere model is used to investigate possible roles of convective scale ocean disturbances induced by atmospheric precipitation on ocean mixed-layer heat and salt budgets. The model couples a cloud resolving model with an embedded mixed layer-ocean circulation model. Five experiment are performed under imposed large-scale atmospheric forcing in terms of vertical velocity derived from the TOGA COARE observations during a selected seven-day period. The dominant variability of mixed-layer temperature and salinity are simulated by the coupled model with imposed large-scale forcing. The mixed-layer temperatures in the coupled experiments with 1-D and 2-D ocean models show similar variations when salinity effects are not included. When salinity effects are included, however, differences in the domain-mean mixed-layer salinity and temperature between coupled experiments with 1-D and 2-D ocean models could be as large as 0.3 PSU and 0.4 C respectively. Without fresh water effects, the nocturnal heat loss over ocean surface causes deep mixed layers and weak cooling rates so that the nocturnal mixed-layer temperatures tend to be horizontally-uniform. The fresh water flux, however, causes shallow mixed layers over convective areas while the nocturnal heat loss causes deep mixed layer over convection-free areas so that the mixed-layer temperatures have large horizontal fluctuations. Furthermore, fresh water flux exhibits larger spatial fluctuations than surface heat flux because heavy rainfall occurs over convective areas embedded in broad non-convective or clear areas, whereas diurnal signals over whole model areas yield high spatial correlation of surface heat flux. As a result, mixed-layer salinities contribute more to the density differences than do mixed-layer temperatures.

Li, Xiaofan; Sui, C.-H.; Lau, K-M.; Adamec, D.

1999-01-01

242

A Data Acquisition and 2-D Flow Measuring Technology in Agricultural Spray Field Based on High Speed Image Processing  

Microsoft Academic Search

In order to solve the faults in usual measurements of droplet distribution and motion in agricultural spraying field, a new method is given for the analysis of droplets characteristics and motion with PDIA (particle \\/ droplet image analysis) and digital image processing technique. During the analysis of the size of droplet and the velocity, images of droplets in spray field

Lu Jun; Li Pingping

2009-01-01

243

a Circleless "2D/3D Total STATION": a Low Cost Instrument for Surveying, Recording Point Clouds, Documentation, Image Acquisition and Visualisation  

NASA Astrophysics Data System (ADS)

Hardware and software of the universally applicable instrument - referred to as a 2D/3D total station - are described here, as well as its practical use. At its core it consists of a 3D camera - often also called a ToF camera, a pmd camera or a RIM-camera - combined with a common industrial 2D camera. The cameras are rigidly coupled with their optical axes in parallel. A new type of instrument was created mounting this 2D/3D system on a tripod in a specific way. Because of it sharing certain characteristics with a total station and a tacheometer, respectively, the new device was called a 2D/3D total station. It may effectively replace a common total station or a laser scanner in some respects. After a brief overview of the prototype's features this paper then focuses on the methodological characteristics for practical application. Its usability as a universally applicable stand-alone instrument is demonstrated for surveying, recording RGB-coloured point clouds as well as delivering images for documentation and visualisation. Because of its limited range (10m without reflector and 150 m to reflector prisms) and low range accuracy (ca. 2 cm to 3 cm) compared to present-day total stations and laser scanners, the practical usage of the 2D/3D total station is currently limited to acquisition of accidents, forensic purpuses, speleology or facility management, as well as architectural recordings with low requirements regarding accuracy. However, the author is convinced that in the near future advancements in 3D camera technology will allow this type of comparatively low cost instrument to replace the total station as well as the laser scanner in an increasing number of areas.

Scherer, M.

2013-07-01

244

Magnetic resonance tomography using elongated transmitter and in-loop receiver arrays for time-efficient 2-D imaging of subsurface aquifer structures  

NASA Astrophysics Data System (ADS)

Surface nuclear magnetic resonance (surface-NMR) is a promising technique for exploring shallow subsurface aquifer structures. Surface-NMR can be applied in environments that are characterized as a 1-D layered Earth. The technique utilizes a single loop and is referred to as magnetic resonance sounding. The technique referred to as magnetic resonance tomography (MRT) allows complex 2-D aquifer structures to be explored. Currently, MRT requires multiple loops and a roll along measurement scheme, which causes long survey time. We propose a loop layout using an elongated transmitter and an in-loop receiver arrays (ETRA) to conduct a 2-D survey with just one measurement. We present a comprehensive comparison between the new layout and the common approaches based on sensitivity and resolution analyses and show synthetic and field data. The results show that ETRA generates subsurface images at sufficient resolution with significantly lower survey times than other loop layouts.

Jiang, C.; Müller-Petke, M.; Lin, J.; Yaramanci, U.

2015-02-01

245

Modeling ECM fiber formation: structure information extracted by analysis of 2D and 3D image sets  

Microsoft Academic Search

Recent evidence supports the notion that biological functions of extracellular matrix (ECM) are highly correlated to its structure. Understanding this fibrous structure is very crucial in tissue engineering to develop the next generation of biomaterials for restoration of tissues and organs. In this paper, we integrate confocal microscopy imaging and image-processing techniques to analyze the structural properties of ECM. We

Jun Wu; Sherry L. Voytik-Harbin; David L. Filmer; Christoph M. Hoffman; Bo Yuan; Ching-Shoei Chiang; Jennis Sturgis; Joseph P. Robinson

2002-01-01

246

Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility study ex vivo  

NASA Astrophysics Data System (ADS)

Magnetic resonance imaging (MRI) and ultrasonography have been used simultaneously in this ex vivo study for the image-guidance of high intensity focused ultrasound (HIFU) treatment in moving tissue. A ventilator-driven balloon produced periodic and non-rigid (i.e. breathing-like) motion patterns in phantoms. MR-compatible ultrasound (US) imaging enabled near real-time 2D motion tracking based on optical flow detection, while near-harmonic reference-free proton resonance frequency shift (PRFS) MR thermometry (MRT) was used to monitor the thermal buildup on line. Reference-free MRT was applied to gradient-echo echo-planar imaging phase maps acquired at the frame rate of 250 to 300 ms/slice with voxel size 1.25×1.25×5 mm3. The MR-US simultaneous imaging was completely free of mutual interferences while minor RF interferences from the HIFU device were detected in the far field of the US images. The effective duty-cycle of the HIFU sonication was close to 100 % and no off-interval was required to temporally decouple it from the ultrasonography. The motion compensation of the HIFU sonication was achieved with an 8 Hz frame rate and sub-millimeter spatial accuracy, both for single-focus mode and for an iterated multi-foci line scan. Near harmonic reference-less PRFS MRT delivered motion-robust thermal maps perpendicular or parallel to the HIFU beam (0.7 °C precision, 0.5 °C absolute accuracy). Out-of-plane motion compensation was not addressed in this study.

Auboiroux, Vincent; Petrusca, Lorena; Viallon, Magalie; Goget, Thomas; Becker, Christoph D.; Salomir, Rares

2012-05-01

247

Ultrasonography-based 2D motion-compensated HIFU sonication integrated with reference-free MR temperature monitoring: a feasibility study ex vivo.  

PubMed

Magnetic resonance imaging (MRI) and ultrasonography have been used simultaneously in this ex vivo study for the image-guidance of high intensity focused ultrasound (HIFU) treatment in moving tissue. A ventilator-driven balloon produced periodic and non-rigid (i.e. breathing-like) motion patterns in phantoms. MR-compatible ultrasound (US) imaging enabled near real-time 2D motion tracking based on optical flow detection, while near-harmonic reference-free proton resonance frequency shift (PRFS) MR thermometry (MRT) was used to monitor the thermal buildup on line. Reference-free MRT was applied to gradient-echo echo-planar imaging phase maps acquired at the frame rate of 250 to 300 ms/slice with voxel size 1.25×1.25×5 mm(3). The MR-US simultaneous imaging was completely free of mutual interferences while minor RF interferences from the HIFU device were detected in the far field of the US images. The effective duty-cycle of the HIFU sonication was close to 100 % and no off-interval was required to temporally decouple it from the ultrasonography. The motion compensation of the HIFU sonication was achieved with an 8 Hz frame rate and sub-millimeter spatial accuracy, both for single-focus mode and for an iterated multi-foci line scan. Near harmonic reference-less PRFS MRT delivered motion-robust thermal maps perpendicular or parallel to the HIFU beam (0.7 °C precision, 0.5 °C absolute accuracy). Out-of-plane motion compensation was not addressed in this study. PMID:22517112

Auboiroux, Vincent; Petrusca, Lorena; Viallon, Magalie; Goget, Thomas; Becker, Christoph D; Salomir, Rares

2012-05-21

248

2D numerical modelling of the gas temperature in a high-temperature high-power strontium atom laser excited by nanosecond pulsed longitudinal discharge in a He-SrBr2 mixture  

NASA Astrophysics Data System (ADS)

Assuming axial symmetry and a uniform power input, a 2D model (r, z) is developed numerically for determination of the gas temperature in the case of a nanosecond pulsed longitudinal discharge in He-SrBr2 formed in a newly-designed large-volume high-temperature discharge tube with additional incompact ZrO2 insulation in the discharge-free zone, in order to find the optimal thermal mode for achievement of maximal output laser parameters. The model determines the gas temperature of a nanosecond pulsed longitudinal discharge in helium with small additives of strontium and bromine.

Chernogorova, T. P.; Temelkov, K. A.; Koleva, N. K.; Vuchkov, N. K.

2014-05-01

249

Communication: Two-dimensional gas-phase coherent anti-Stokes Raman spectroscopy (2D-CARS): Simultaneous planar imaging and multiplex spectroscopy in a single laser shot  

NASA Astrophysics Data System (ADS)

Coherent anti-Stokes Raman spectroscopy (CARS) has been widely used as a powerful tool for chemical sensing, molecular dynamics measurements, and rovibrational spectroscopy since its development over 30 years ago, finding use in fields of study as diverse as combustion diagnostics, cell biology, plasma physics, and the standoff detection of explosives. The capability for acquiring resolved CARS spectra in multiple spatial dimensions within a single laser shot has been a long-standing goal for the study of dynamical processes, but has proven elusive because of both phase-matching and detection considerations. Here, by combining new phase matching and detection schemes with the high efficiency of femtosecond excitation of Raman coherences, we introduce a technique for single-shot two-dimensional (2D) spatial measurements of gas phase CARS spectra. We demonstrate a spectrometer enabling both 2D plane imaging and spectroscopy simultaneously, and present the instantaneous measurement of 15 000 spatially correlated rotational CARS spectra in N2 and air over a 2D field of 40 mm2.

Bohlin, Alexis; Kliewer, Christopher J.

2013-06-01

250

Left atrial deformation parameters in patients with non-alcoholic fatty liver disease: a 2D speckle tracking imaging study.  

PubMed

The presence of the metabolic syndrome is a strong predictor for the presence of NASH (non-alcoholic steatohepatitis) in patients with NAFLD (non-alcoholic fatty liver disease). In the present study, we assessed LA (left atrial) deformation parameters in patients with NAFLD using 2D-STE (speckle tracking echocardiography) and to investigate if any changes exist between subgroups of the NAFLD. A total of 55 NAFLD patients and 21 healthy controls were included in the study. The diagnosis of NAFLD was based on liver biopsy. After patients were categorized into groups according to histopathological analysis (simple steatosis, borderline NASH, definitive NASH), all patients underwent echocardiography with Doppler examination. In the 2D-STE analysis of the left atrium, LA-Res (peak LA strain during ventricular systole), LA-Pump (peak LA strain during atrial systole), LA-SR(S) (peak LA strain rate during ventricular systole), LA-SR(E) (peak LA strain rate during early diastole) and LA-SR(A) (peak LA strain rate during atrial systole) were obtained. LA-Res, LA-Pump and LA-SR(A) were lower in the NAFLD group than in the control group. LA-Res was found to be significantly lower in NAFLD subgroups compared with healthy subjects (43.9±14.2 in healthy controls compared with 31.4±8.3 with simple steatosis, 32.8±12.8 with borderline NASH and 33.8±9.0 with definitive NASH). LA-Pump was significantly lower in the NAFLD group (18.2±3.1 in healthy controls compared with 13.3±4.7 with borderline NASH and 14.4±4.7 with definitive NASH). There were significant differences in LA-SR(A) between healthy controls compared with simple steatosis and borderline NASH (-1.56±0.36 compared with 1.14±0.38 and 1.24±0.32 respectively). Correlation analysis showed significant correlation of LA-Res values with E (early diastolic peak velocity)/E(m) (early diastolic mitral annular velocity) ratio (r=-0.50, P?0.001), with LAVI (LA volume index; r=-0.45, P?0.001) and with V(p) (propagation velocity; r=0.39, P?0.001). 2D-STE-based LA deformation parameters are impaired in patients with NAFLD with normal systolic function. Although LA-Res and pump function parameters might be useful in estimating LV (left ventricular) filling pressure in the NAFLD patient group, it could not be used for differentiating the subgroups. PMID:23947743

Kocabay, Gonenc; Karabay, Can Yucel; Colak, Yasar; Oduncu, Vecih; Kalayci, Arzu; Akgun, Taylan; Guler, Ahmet; Kirma, Cevat

2014-02-01

251

Model-based measurement of food portion size for image-based dietary assessment using 3D/2D registration  

NASA Astrophysics Data System (ADS)

Dietary assessment is important in health maintenance and intervention in many chronic conditions, such as obesity, diabetes and cardiovascular disease. However, there is currently a lack of convenient methods for measuring the volume of food (portion size) in real-life settings. We present a computational method to estimate food volume from a single photographic image of food contained on a typical dining plate. First, we calculate the food location with respect to a 3D camera coordinate system using the plate as a scale reference. Then, the food is segmented automatically from the background in the image. Adaptive thresholding and snake modeling are implemented based on several image features, such as color contrast, regional color homogeneity and curve bending degree. Next, a 3D model representing the general shape of the food (e.g., a cylinder, a sphere, etc) is selected from a pre-constructed shape model library. The position, orientation and scale of the selected shape model are determined by registering the projected 3D model and the food contour in the image, where the properties of the reference are used as constraints. Experimental results using various realistically shaped foods with known volumes demonstrated satisfactory performance of our image-based food volume measurement method even if the 3D geometric surface of the food is not completely represented in the input image.

Chen, Hsin-Chen; Jia, Wenyan; Yue, Yaofeng; Li, Zhaoxin; Sun, Yung-Nien; Fernstrom, John D.; Sun, Mingui

2013-10-01

252

Preliminary 3D Depth Migration of a Network of 2D Seismic Lines for Fault Imaging at a Pyramid Lake, Nevada Geothermal Prospect  

NASA Astrophysics Data System (ADS)

Many of the current geothermal power plants in western Nevada are found in extensional regimes that are associated with dilational faults and fault intersections. Most of these systems are blind and require advanced seismic imaging techniques to map target faults and reduce drilling risk. Surface features including fumaroles, hot springs, or hydrothermal deposits, like travertine and tufa, are indicators of a potential geothermal resource at depth, which still require advanced seismic imaging techniques for efficient development. One of the most notable locations of tufa deposits in western Nevada is in and around Pyramid Lake. With the abundant hydrothermal venting in the area, the tufa deposits indicate a prime locations for geothermal exploration. In 2010 and previous years, we collected about 38 km of vibroseis reflection data in a network of sixteen 2D lines of various orientations off the northwest side of Pyramid Lake. Most of these lines are within an area of only 10 square km. The 2010 survey used three heavy vibrators, and recorded 6-sec records of 8-sec, 10-100 Hz linear sweeps. Source and receiver spacing varied from 17-67 m, with up to 240 channels live for maximum offsets varying from 1000-5000 m, depending on line length. Preliminary 2D processing with first-arrival velocity optimization shows strong fault-plane reflections and several sets of stratigraphic terminations against faults. We interpret three sets of faults, which appear to intersect at about 1.25 km depth. Despite the three fault sets each appearing on several lines, only the lines trending perpendicular to fault strike show direct imaging of fault-plane reflections. We hypothesize that a 3D depth migration will reveal additional direct images of the faults. We are testing this hypothesis with a 3D Kirchhoff prestack migration of the data from this dense network of 2D lines. The 3D depth migration will take full account of lateral velocity changes. This migration should directly image additional steeply dipping fault planes at this prospect. The Pyramid Lake Paiute Tribe will use this information to build 3D geologic and hydrologic models for geothermal power development.

Frary, R.; Louie, J. N.; Pullammanappallil, S.; Eisses, A.

2011-12-01

253

Electrostatic layer correction with image charges: a linear scaling method to treat slab 2D+h systems with dielectric interfaces.  

PubMed

A fast algorithm for dealing with electrostatic interactions in partially periodic systems that are confined along the nonperiodic direction by two planar dielectric interfaces is presented. The method is a generalization of the electrostatic layer correction (ELC) method of Arnold et al. [J. Chem. Phys. 117, 2496 (2002)], and employs an exact relation between the 2D+h system and a three-dimensional (3D) periodic system. The terms connecting the two systems can be evaluated linearly in the number of charges. Thus, the method shows overall the scaling of the underlying method employed to handle the Coulombic 3D case. Moreover, our algorithm can accurately handle multiple polarization image charges due to the dielectric interfaces as well as all the periodic images due to the periodic boundary conditions and has full control over the errors depending on the underlying method used for the 3D periodic case. PMID:19045847

Tyagi, Sandeep; Arnold, Axel; Holm, Christian

2008-11-28

254

A novel technique for single-shot energy-resolved 2D x-ray imaging of plasmas relevant for the inertial confinement fusion  

SciTech Connect

A novel x-ray diagnostic of laser-fusion plasmas is described, allowing 2D monochromatic images of hot, dense plasmas to be obtained in any x-ray photon energy range, over a large domain, on a single-shot basis. The device (named energy-encoded pinhole camera) is based upon the use of an array of many pinholes coupled to a large area CCD camera operating in the single-photon mode. The available x-ray spectral domain is only limited by the quantum efficiency of scientific-grade x-ray CCD cameras, thus extending from a few keV up to a few tens of keV. Spectral 2D images of the emitting plasma can be obtained at any x-ray photon energy provided that a sufficient number of photons had been collected at the desired energy. Results from recent inertial confinement fusion related experiments will be reported in order to detail the new diagnostic.

Labate, L.; Koester, P.; Levato, T.; Gizzi, L. A. [Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Consiglio Nazionale delle Ricerche, Pisa (Italy)

2012-10-15

255

Crystal structure and temperature-dependent fluorescent property of a 2D cadmium (II) complex based on 3,6-dibromobenzene-1,2,4,5-tetracarboxylic acid  

NASA Astrophysics Data System (ADS)

A new cadmium (II) organic coordination polymers [Cd(dbtec)0.5(H2O)3]·H2O (1), has been constructed based on 3,6-dibromobenzene-1,2,4,5-tetracarboxylic acid (H4dbtec), and characterized by elemental analysis (EA), infrared spectroscopy (IR), powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. In 1, ?2-?1:?1 and ?4-?2:?2 dbtec ligands link four hepta-coordinated CdII ions to form a 2D 44 topological layer structure, which is further connected into an interesting 3D network by hydrogen bond and Br⋯O halogen bond. Moreover, the thermal stabilities, solid ultraviolet spectroscopy and temperature-dependent fluorescent properties of 1 were investigated.

Zhang, Liang-Liang; Guo, Yu; Wei, Yan-Hui; Guo, Jie; Wang, Xing-Po; Sun, Dao-Feng

2013-04-01

256

A novel method to acquire 3D data from serial 2D images of a dental cast  

NASA Astrophysics Data System (ADS)

This paper introduced a newly developed method to acquire three-dimensional data from serial two-dimensional images of a dental cast. The system consists of a computer and a set of data acquiring device. The data acquiring device is used to take serial pictures of the a dental cast; an artificial neural network works to translate two-dimensional pictures to three-dimensional data; then three-dimensional image can reconstruct by the computer. The three-dimensional data acquiring of dental casts is the foundation of computer-aided diagnosis and treatment planning in orthodontics.

Yi, Yaxing; Li, Zhongke; Chen, Qi; Shao, Jun; Li, Xinshe; Liu, Zhiqin

2007-05-01

257

High spatiotemporal resolution measurement of regional lung air volumes from 2D phase contrast x-ray images  

SciTech Connect

Purpose: Described herein is a new technique for measuring regional lung air volumes from two-dimensional propagation-based phase contrast x-ray (PBI) images at very high spatial and temporal resolution. Phase contrast dramatically increases lung visibility and the outlined volumetric reconstruction technique quantifies dynamic changes in respiratory function. These methods can be used for assessing pulmonary disease and injury and for optimizing mechanical ventilation techniques for preterm infants using animal models. Methods: The volumetric reconstruction combines the algorithms of temporal subtraction and single image phase retrieval (SIPR) to isolate the image of the lungs from the thoracic cage in order to measure regional lung air volumes. The SIPR algorithm was used to recover the change in projected thickness of the lungs on a pixel-by-pixel basis (pixel dimensions {approx}16.2 {mu}m). The technique has been validated using numerical simulation and compared results of measuring regional lung air volumes with and without the use of temporal subtraction for removing the thoracic cage. To test this approach, a series of PBI images of newborn rabbit pups mechanically ventilated at different frequencies was employed. Results: Regional lung air volumes measured from PBI images of newborn rabbit pups showed on average an improvement of at least 20% in 16% of pixels within the lungs in comparison to that measured without the use of temporal subtraction. The majority of pixels that showed an improvement was found to be in regions occupied by bone. Applying the volumetric technique to sequences of PBI images of newborn rabbit pups, it is shown that lung aeration at birth can be highly heterogeneous. Conclusions: This paper presents an image segmentation technique based on temporal subtraction that has successfully been used to isolate the lungs from PBI chest images, allowing the change in lung air volume to be measured over regions as small as the pixel size. Using this technique, it is possible to measure changes in regional lung volume at high spatial and temporal resolution during breathing at much lower x-ray dose than would be required using computed tomography.

Leong, Andrew F. T.; Islam, M. Sirajul; Kitchen, Marcus J. [School of Physics, Monash University, Victoria 3800 (Australia); Fouras, Andreas [Division of Biological Engineering, Monash University, Victoria 3800 (Australia); Wallace, Megan J.; Hooper, Stuart B. [Ritchie Centre and Department of Obstetrics and Gynaecology, Monash Institute of Medical Research, Monash University, Victoria 3168 (Australia)

2013-04-15

258

Watershed and Random Walks based Depth Estimation for Semi-Automatic 2D to 3D Image Conversion  

E-print Network

College of Higher Education, Hong Kong SAR, China ABSTRACT Depth map estimation from a single image or semi-automatic, are proposed before. Quality of the depth map from automatic methods is low can generate a better quality of depth map based on the user-defined labels, which indicate a rough

Po, Lai-Man

259

A 2D/3D image analysis system to track fluorescently labeled structures in rod-shaped cells: application to measure spindle pole asymmetry during mitosis  

PubMed Central

Background The yeast Schizosaccharomyces pombe is frequently used as a model for studying the cell cycle. The cells are rod-shaped and divide by medial fission. The process of cell division, or cytokinesis, is controlled by a network of signaling proteins called the Septation Initiation Network (SIN); SIN proteins associate with the SPBs during nuclear division (mitosis). Some SIN proteins associate with both SPBs early in mitosis, and then display strongly asymmetric signal intensity at the SPBs in late mitosis, just before cytokinesis. This asymmetry is thought to be important for correct regulation of SIN signaling, and coordination of cytokinesis and mitosis. In order to study the dynamics of organelles or large protein complexes such as the spindle pole body (SPB), which have been labeled with a fluorescent protein tag in living cells, a number of the image analysis problems must be solved; the cell outline must be detected automatically, and the position and signal intensity associated with the structures of interest within the cell must be determined. Results We present a new 2D and 3D image analysis system that permits versatile and robust analysis of motile, fluorescently labeled structures in rod-shaped cells. We have designed an image analysis system that we have implemented as a user-friendly software package allowing the fast and robust image-analysis of large numbers of rod-shaped cells. We have developed new robust algorithms, which we combined with existing methodologies to facilitate fast and accurate analysis. Our software permits the detection and segmentation of rod-shaped cells in either static or dynamic (i.e. time lapse) multi-channel images. It enables tracking of two structures (for example SPBs) in two different image channels. For 2D or 3D static images, the locations of the structures are identified, and then intensity values are extracted together with several quantitative parameters, such as length, width, cell orientation, background fluorescence and the distance between the structures of interest. Furthermore, two kinds of kymographs of the tracked structures can be established, one representing the migration with respect to their relative position, the other representing their individual trajectories inside the cell. This software package, called “RodCellJ”, allowed us to analyze a large number of S. pombe cells to understand the rules that govern SIN protein asymmetry. (Continued on next page) (Continued from previous page) Conclusions “RodCellJ” is freely available to the community as a package of several ImageJ plugins to simultaneously analyze the behavior of a large number of rod-shaped cells in an extensive manner. The integration of different image-processing techniques in a single package, as well as the development of novel algorithms does not only allow to speed up the analysis with respect to the usage of existing tools, but also accounts for higher accuracy. Its utility was demonstrated on both 2D and 3D static and dynamic images to study the septation initiation network of the yeast Schizosaccharomyces pombe. More generally, it can be used in any kind of biological context where fluorescent-protein labeled structures need to be analyzed in rod-shaped cells. Availability RodCellJ is freely available under http://bigwww.epfl.ch/algorithms.html. PMID:23622681

2013-01-01

260

2D/3D Image fusion for accurate target localization and evaluation of a mask based stereotactic system in fractionated stereotactic radiotherapy of cranial lesions  

SciTech Connect

The purpose of this study was to evaluate the accuracy of a two-dimensional (2D) to three-dimensional (3D) image-fusion-guided target localization system and a mask based stereotactic system for fractionated stereotactic radiotherapy (FSRT) of cranial lesions. A commercial x-ray image guidance system originally developed for extracranial radiosurgery was used for FSRT of cranial lesions. The localization accuracy was quantitatively evaluated with an anthropomorphic head phantom implanted with eight small radiopaque markers (BBs) in different locations. The accuracy and its clinical reliability were also qualitatively evaluated for a total of 127 fractions in 12 patients with both kV x-ray images and MV portal films. The image-guided system was then used as a standard to evaluate the overall uncertainty and reproducibility of the head mask based stereotactic system in these patients. The phantom study demonstrated that the maximal random error of the image-guided target localization was {+-}0.6 mm in each direction in terms of the 95% confidence interval (CI). The systematic error varied with measurement methods. It was approximately 0.4 mm, mainly in the longitudinal direction, for the kV x-ray method. There was a 0.5 mm systematic difference, primarily in the lateral direction, between the kV x-ray and the MV portal methods. The patient study suggested that the accuracy of the image-guided system in patients was comparable to that in the phantom. The overall uncertainty of the mask system was {+-}4 mm, and the reproducibility was {+-}2.9 mm in terms of 95% CI. The study demonstrated that the image guidance system provides accurate and precise target positioning.

Jin, J.-Y.; Ryu, Samuel; Faber, Kathleen; Mikkelsen, Tom; Chen Qing; Li Shidong; Movsas, Benjamin [Department of Radiation Oncology, Henry Ford Hospital, 2799 W. Grand Boulevard, Detroit, Michigan 48202 (United States)

2006-12-15

261

Proteome signatures for stress and starvation in Bacillus subtilis as revealed by a 2-D gel image color coding approach.  

PubMed

In this paper we have defined proteome signatures of Bacillus subtilis in response to heat, salt, peroxide, and superoxide stress as well as after starvation for ammonium, tryptophan, glucose, and phosphate using the 2-D gel-based approach. In total, 79 stress-induced and 155 starvation-induced marker proteins were identified including 50% that are not expressed in the vegetative proteome. Fused proteome maps and a color coding approach have been used to define stress-specific regulons that are involved in specific adaptative functions (HrcA for heat, PerR and Fur for oxidative stress, RecA for peroxide, CymR and S-box for superoxide stress). In addition, starvation-specific regulons are defined that are involved in the uptake or utilization of alternative nutrient sources (TnrA, sigmaL/BkdR for ammonium; tryptophan-activated RNA-binding attenuation protein for tryptophan; CcpA, CcpN, sigmaL/AcoR for glucose; PhoPR for phosphate starvation). The general stress or starvation proteome signatures include the CtsR, Spx, sigmaL/RocR, sigmaB, sigmaH, CodY, sigmaF, and sigmaE regulons. Among these, the Spx-dependent oxidase NfrA was induced by all stress conditions indicating stress-induced protein damages. Finally, a subset of sigmaH-dependent proteins (sporulation response regulator, YvyD, YtxH, YisK, YuxI, YpiB) and the CodY-dependent aspartyl phosphatase RapA were defined as general starvation proteins that indicate the transition to stationary phase caused by starvation. PMID:16847875

Tam, Le Thi; Antelmann, Haike; Eymann, Christine; Albrecht, Dirk; Bernhardt, Jörg; Hecker, Michael

2006-08-01

262

2D imaging of intracapillary Hb-concentration and oxygenation in the skin of the human forehead in different ages  

NASA Astrophysics Data System (ADS)

On the capillary level of intact organs of humans and mammals, fields of gradients of all measurable parameters are found exclusively. Therefore, a precise monitoring e.g. of hemoglobin concentration (Hb) and oxygenation (HbO2) in the microcosm of blood capillaries is only possible when the heterogeneity of tissue data is recorded at a representative number of measuring points. For the collecting of the required data both stochastic or imaging techniques can be applied.

Kessler, Manfred D.; Cristea, Paul D.; Knaelmann, Rainer; Wittwer, Philipp

2002-06-01

263

2D and 3D Refraction Based X-ray Imaging Suitable for Clinical and Pathological Diagnosis  

Microsoft Academic Search

The first observation of micro papillary (MP) breast cancer by x-ray dark-field imaging (XDFI) and the first observation of the 3D x-ray internal structure of another breast cancer, ductal carcinoma in-situ (DCIS), are reported. The specimen size for the sheet-shaped MP was 26 mm × 22 mm × 2.8 mm, and that for the rod-shaped DCIS was 3.6 mm in

Masami Ando; Hiroko Bando; Zhihua Chen; Yoshinori Chikaura; Chang-Hyuk Choi; Tokiko Endo; Hiroyasu Esumi; Li Gang; Eiko Hashimoto; Keiichi Hirano; Kazuyuki Hyodo; Shu Ichihara; Sanghoon Jheon; Hongtae Kim; Jongki Kim; Tatsuro Kimura; Changhyun Lee; Anton Maksimenko; Chiho Ohbayashi; Sunghwan Park; Daisuke Shimao; Hiroshi Sugiyama; Jintian Tang; Ei Ueno; Katsuhito Yamasaki; Tetsuya Yuasa

2007-01-01

264

Infrared absorption imaging of 2D supersonic jet expansions: Free expansion, cluster formation, and shock wave patterns  

NASA Astrophysics Data System (ADS)

N2O/He gas mixtures are expanded through a 10 × 0.5 mm2 slit nozzle and imaged by direct absorption vibrational spectroscopy, employing a HgCdTe focal plane array detector after interferometric modulation. N2O cluster formation in the free supersonic expansion is visualized. The expansion structure behind the frontal shock is investigated as a function of background pressure. At high pressures, a sequence of stationary density peaks along a narrow directed flow channel is characterized. The potential of the technique for the elucidation of aggregation mechanisms is emphasized.

Zischang, Julia; Suhm, Martin A.

2013-07-01

265

2-D PSTD Simulation of the time-reversed ultrasound-encoded deep-tissue imaging technique  

PubMed Central

We present a robust simulation technique to model the time-reversed ultrasonically encoded (TRUE) technique for deep-tissue imaging. The pseudospectral time-domain (PSTD) algorithm is employed to rigorously model the electromagnetic wave interaction of light propagating through a macroscopic scattering medium. Based upon numerical solutions of Maxwell’s equations, the amplitude and phase are accurately accounted for to analyze factors that affect the TRUE propagation of light through scattering media. More generally, we demonstrate the feasibility of modeling light propagation through a virtual tissue model of macroscopic dimensions with numerical solutions of Maxwell’s equations. PMID:24688821

Tseng, Snow H.; Ting, Wei-Lun; Wang, Shiang-Jiu

2014-01-01

266

Reconstruction of 3D lung models from 2D planning data sets for Hodgkin's lymphoma patients using combined deformable image registration and navigator channels  

SciTech Connect

Purpose: Late complications (cardiac toxicities, secondary lung, and breast cancer) remain a significant concern in the radiation treatment of Hodgkin's lymphoma (HL). To address this issue, predictive dose-risk models could potentially be used to estimate radiotherapy-related late toxicities. This study investigates the use of deformable image registration (DIR) and navigator channels (NCs) to reconstruct 3D lung models from 2D radiographic planning images, in order to retrospectively calculate the treatment dose exposure to HL patients treated with 2D planning, which are now experiencing late effects. Methods: Three-dimensional planning CT images of 52 current HL patients were acquired. 12 image sets were used to construct a male and a female population lung model. 23 ''Reference'' images were used to generate lung deformation adaptation templates, constructed by deforming the population model into each patient-specific lung geometry using a biomechanical-based DIR algorithm, MORFEUS. 17 ''Test'' patients were used to test the accuracy of the reconstruction technique by adapting existing templates using 2D digitally reconstructed radiographs. The adaptation process included three steps. First, a Reference patient was matched to a Test patient by thorax measurements. Second, four NCs (small regions of interest) were placed on the lung boundary to calculate 1D differences in lung edges. Third, the Reference lung model was adapted to the Test patient's lung using the 1D edge differences. The Reference-adapted Test model was then compared to the 3D lung contours of the actual Test patient by computing their percentage volume overlap (POL) and Dice coefficient. Results: The average percentage overlapping volumes and Dice coefficient expressed as a percentage between the adapted and actual Test models were found to be 89.2{+-}3.9% (Right lung=88.8%; Left lung=89.6%) and 89.3{+-}2.7% (Right=88.5%; Left=90.2%), respectively. Paired T-tests demonstrated that the volumetric reconstruction method made a statistically significant improvement to the population lung model shape (p<0.05). The error in the results were also comparable to the volume overlap difference observed between inhale and exhale lung volumes during free-breathing respiratory motion (POL:p=0.43; Dice:p=0.20), which implies that the accuracies of the reconstruction method are within breathing constraints and would not be the confining factor in estimating normal tissue dose exposure. Conclusions: The result findings show that the DIR-NC technique can achieve a high degree of reconstruction accuracy, and could be useful in approximating 3D dosimetric representations of historical 2D treatment. In turn, this could provide a better understanding of the biophysical relationship between dose-volume exposure and late term radiotherapy effects.

Ng, Angela; Nguyen, Thao-Nguyen; Moseley, Joanne L.; Hodgson, David C.; Sharpe, Michael B.; Brock, Kristy K. [Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9, Canada and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada); Radiation Medicine Program, Princess Margaret Hospital, University Health Network, Toronto, Ontario M5G 2M9 (Canada); Department of Medical Biophysics, University of Toronto, Toronto, Ontario M5G 2M9 (Canada) and Department of Radiation Oncology, University of Toronto, Toronto, Ontario M5G 2M9 (Canada)

2010-03-15

267

Cobalt60 and proton radiation effects on large format, 2-D, CCD arrays for an Earth imaging application  

Microsoft Academic Search

Cobalt60 and 10-MeV proton irradiations have been carried out on n-buried channel frame transfer CCDs (charge coupled devices) in order to study changes in charge transfer efficiency (CTE) and dark current for room temperature, 1 ?s\\/pixel, readout conditions. Bias dependence and post-annealing effects were observed for ionization damage. CTE effects are explained in terms of capture and emission from deep

G. R. Hopkinson

1992-01-01

268

2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region  

SciTech Connect

A new tangential two-dimensional soft x-ray imaging system (SXRIS) is being designed to examine the edge island structure in the lower X-point region of DIII-D. Plasma shielding and/or amplification of the calculated vacuum islands may play a role in the suppression of edge-localized modes via resonant magnetic perturbations (RMPs). The SXRIS is intended to improve the understanding of three-dimensional (3D) phenomena associated with RMPs. This system utilizes a tangential view with a pinhole imaging system and spectral filtering with beryllium foils. SXR emission is chosen to avoid line radiation and allows suitable signal at the top of a H-mode pedestal where T{sub e}{approx}1-2 keV. A synthetic diagnostic calculation based on 3D SXR emissivity estimates is used to help assess signal levels and resolution of the design. A signal-to-noise ratio of 10 at 1 cm resolution is expected for the perturbed signals, which are sufficient to resolve most of the predicted vacuum island sizes.

Shafer, M. W.; Battaglia, D. J.; Unterberg, E. A.; Hillis, D. L.; Maingi, R. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Evans, T. E. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)

2010-10-15

269

2D soft x-ray system on DIII-D for imaging the magnetic topology in the pedestal region  

SciTech Connect

A new tangential two-dimensional soft x-ray imaging system (SXRIS) is being designed to examine the edge island structure in the lower X-point region of DIII-D. Plasma shielding and/or amplification of the calculated vacuum islands may play a role in the suppression of edge-localized modes via resonant magnetic perturbations (RMPs). The SXRIS is intended to improve the understanding of three-dimensional (3D) phenomena associated with RMPs. This system utilizes a tangential view with a pinhole imaging system and spectral filtering with beryllium foils. SXR emission is chosen to avoid line radiation and allows suitable signal at the top of a H-mode pedestal where T(e) similar to 1-2 keV. A synthetic diagnostic calculation based on 3D SXR emissivity estimates is used to help assess signal levels and resolution of the design. A signal-to-noise ratio of 10 at 1 cm resolution is expected for the perturbed signals, which are sufficient to resolve most of the predicted vacuum island sizes.

Shafer, M.W. [Oak Ridge National Laboratory (ORNL); Battaglia, D. J. [Oak Ridge National Laboratory (ORNL); Unterberg, Ezekial A [ORNL; Evans, T. E. [General Atomics, San Diego; Hillis, Donald Lee [ORNL; Maingi, R. [Oak Ridge National Laboratory (ORNL)

2010-01-01

270

Near-infrared (NIR) imaging analysis of polylactic acid (PLA) nanocomposite by multiple-perturbation two-dimensional (2D) correlation spectroscopy  

NASA Astrophysics Data System (ADS)

Multiple-perturbation two-dimensional (2D) correlation spectroscopy was applied to sets of near-infrared (NIR) imaging data of polylactic acid (PLA) nanocomposite samples undergoing UV degradation. Incorporation of clay nanoparticles substantially lowers the surface free energy barrier for the nucleation of PLA and eventually increases the frequency of the spontaneous nucleation of PLA crystals. Thus, when exposed to external stimuli such as UV light, PLA nanocomposite may show different structure alternation depending on the clay dispersion. Multiple-perturbation 2D correlation analysis of the PLA nanocomposite samples revealed different spatial variation between crystalline and amorphous structure of PLA, and the phenomenon especially becomes acute in the region where the clay particles are coagulated. The incorporation of the clay leads to the cleavage-induced crystallization of PLA when the sample is subjected to the UV light. The additional development of the ordered crystalline structure then works favorably to restrict the initial degradation of the polymer, providing the delay in the weight loss of the PLA.

Shinzawa, Hideyuki; Murakami, Takurou N.; Nishida, Masakazu; Kanematsu, Wataru; Noda, Isao

2014-07-01

271

Modeling and Measurement of 3D Deformation of Scoliotic Spine Using 2D X-ray Images  

NASA Astrophysics Data System (ADS)

Scoliosis causes deformations such as twisting and lateral bending of the spine. To correct scoliotic deformation, the extents of 3D spinal deformation need to be measured. This paper studies the modeling and measurement of scoliotic spine based on 3D curve model. Through modeling the spine as a 3D Cosserat rod, the 3D structure of a scoliotic spine can be recovered by obtaining the minimum potential energy registration of the rod to the scoliotic spine in the x-ray image. Test results show that it is possible to obtain accurate 3D reconstruction using only the landmarks in a single view, provided that appropriate boundary conditions and elastic properties are included as constraints.

Li, Hao; Leow, Wee Kheng; Huang, Chao-Hui; Howe, Tet Sen

272

Temperature sensitivity of Cu K(alpha) imaging efficiency using a spherical Bragg reflecting crystal  

SciTech Connect

The Vulcan laser facility at the Rutherford Appleton Laboratory was used to study the interaction of a 75 J 10 ps, high intensity laser beam with low-mass solid, Cu targets. Two instruments were fielded as diagnostics of the Cu K-shell emission from the targets: A single photon counting CCD spectrometer provided the absolute K{sub {alpha}} yield and a spherically bent Bragg crystal recorded 2D monochromatic images with a spatial resolution of 10 {micro}m. Due to the shifting and broadening of the K{sub {alpha}} spectral lines with increasing temperature, there is a temperature dependence of the crystal collection efficiency. This provides a temperature diagnostic when cross calibrated against a single hit CCD spectrometer, and it affects measurements of the spatial pattern of electron transport. The experimental data showing changing collection efficiency are presented. The results are discussed in light of modeling of the temperature-dependent spectrum of Cu K-shell emission.

Akli, K U; Key, M H; Chung, H K; Hansen, S B; Freeman, R R; Chen, M H; Gregori, G; Hatchett, S; Hey, D; Izumi, N; King, J A; Kuba, J; Norreys, P; Mackinnon, A J; Murphy, C D; Snavely, R; Stepehens, R; Stoeckel, C; Theobald, W; Zhang, B

2006-08-07

273

Kinematic Analysis of Healthy Hips during Weight-Bearing Activities by 3D-to-2D Model-to-Image Registration Technique.  

PubMed

Dynamic hip kinematics during weight-bearing activities were analyzed for six healthy subjects. Continuous X-ray images of gait, chair-rising, squatting, and twisting were taken using a flat panel X-ray detector. Digitally reconstructed radiographic images were used for 3D-to-2D model-to-image registration technique. The root-mean-square errors associated with tracking the pelvis and femur were less than 0.3?mm and 0.3° for translations and rotations. For gait, chair-rising, and squatting, the maximum hip flexion angles averaged 29.6°, 81.3°, and 102.4°, respectively. The pelvis was tilted anteriorly around 4.4° on average during full gait cycle. For chair-rising and squatting, the maximum absolute value of anterior/posterior pelvic tilt averaged 12.4°/11.7° and 10.7°/10.8°, respectively. Hip flexion peaked on the way of movement due to further anterior pelvic tilt during both chair-rising and squatting. For twisting, the maximum absolute value of hip internal/external rotation averaged 29.2°/30.7°. This study revealed activity dependent kinematics of healthy hip joints with coordinated pelvic and femoral dynamic movements. Kinematics' data during activities of daily living may provide important insight as to the evaluating kinematics of pathological and reconstructed hips. PMID:25506056

Hara, Daisuke; Nakashima, Yasuharu; Hamai, Satoshi; Higaki, Hidehiko; Ikebe, Satoru; Shimoto, Takeshi; Hirata, Masanobu; Kanazawa, Masayuki; Kohno, Yusuke; Iwamoto, Yukihide

2014-01-01

274

In vivo estimation of flexor digitorum superficialis tendon displacement with speckle tracking on 2-D ultrasound images using Laplacian, Gaussian and Rayleigh techniques.  

PubMed

This study applies 2-D speckle tracking using B-scan ultrasound imaging to estimate the instantaneous and total displacement of the middle flexor digitorum superficialis (FDS) tendon proximal to the wrist. This is achieved by performing the study with human patients, during regular carpal tunnel surgeries. B-Scan images were collected with a 12-MHz transducer placed proximal to the wrist, while a video microscope simultaneously imaged the exposed flexor tendons in the palm as a reference for validation. The accuracy of the proposed speckle-based tracking method is compared using log-compressed Rayleigh (Fisher-Tippet)-, Gaussian (sum of squared differences)- and Laplacian (sum of absolute differences)-based statistics as similarity measures. Overall, tracking was successful and the Rayleigh technique performed better than the Laplacian or Gaussian technique. One goal of this research was to non-invasively monitor FDS tendon displacement in the wrist for the purposes of controlling a prosthetic device. An additional goal was to obtain pre- and post-operative clinical information. PMID:24342915

Stegman, Kelly J; Djurickovic, Slobodan; Dechev, Nikolai

2014-03-01

275

Development of an integrated approach for evaluation of 2-D gel image analysis: Impact of multiple proteins in single spots on comparative proteomics in conventional 2-D gel/MALDI workflow  

Technology Transfer Automated Retrieval System (TEKTRAN)

With 2-D gel mapping, it is often observed that essentially identical proteins migrate to different positions in the gel, while some seemingly well-resolved protein spots consist of multiple proteins. These observations can undermine the validity of gel-based comparative proteomic studies. Through...

276

The 2009-11 SAHKE Experiment: 2D velocity imaging across the interseismically locked southern Hikurangi margin, Wellington, New Zealand  

NASA Astrophysics Data System (ADS)

The passive and controlled source Seismic Array HiKurangi Experiment (SAHKE) project is designed to investigate the structure of the forearc and the physical parameters controlling locking at the Australian-Pacific subduction plate boundary beneath the southern North Island. SAHKE seismic data were acquired between November 2009 and April 2010 and again in May 2011, encompassing the full extent of the locked portion of the plate interface beneath Wellington along a central transect. 400 km of marine multichannel seismic data were acquired on two SAHKE profiles across the convergent margin and recorded by 38 IRIS/PASSCAL short period sensors along the main onshore-offshore transect. The onshore component of the survey comprised 12 in-line borehole explosive sources (500 kg) distributed approximately 8 km apart along the central transect. The energy was recorded on 835 seismic stations (277 3-component and 558 vertical sensors) deployed at 100 m spacing, except for a denser section of 50 m spacing in the centre of the spread. The 3C stations were spaced at 300 m spacing. We used a tomographic inversion of 18000 first arrivals, from the combined onshore-offshore and onshore components, to construct a Vp image of the crust that is well resolved to 20-25 km depth. The resulting velocity models shows top of Pacific plate subducting as a strong velocity gradient offshore to the east but this gradient decreases beneath the land and also coincides with a low velocity lower crust. A stacked section of the land shots also reveals the low velocity zone to be highly imbricated and consistent with subducted sedimentary channel material being underplated in the region of strongest geodetically determined plate coupling. The Wairarapa fault, a prominent upper crustal splay fault, appears to dip westward and merge with the underplated reflectivity beneath the Tararua Ranges.

Henrys, S. A.; Wech, A.; Sato, H.; Okaya, D. A.; Iwasaki, T.; Stern, T. A.; Savage, M. K.; Mochizuki, K.; Kurashimo, E.; Sutherland, R.

2012-12-01

277

Adsorption and thermal decomposition of C{sub 2}D{sub 5}I on the (110) and (111) planes of NiAl: A temperature programmed deposition and x-ray photoelectron spectroscopy study  

SciTech Connect

This study investigates the adsorption and the subsequent thermal decompoistion of d{sub 5}-iodoethane (C{sub 2}D{sub 5}I) on the (110) and (111) planes of NiAl using temperature programmed desorption (TPD) and x-ray photoelectron spectroscopy (XPS). Both I 3d{sub 5/2} and C 1s XPS data show that C{sub 2}D{sub 5}I adsorbs molecularly on both NiAl surfaces at 120 K. Upon heating the sample, the C{endash}I bond starts to cleave and the scission of this bond is complete on NiAl(110) and NiAl(111) by 150 and 300 K, respectively. It is suspected that this cleavage results in the formation of C{sub 2}D{sub 5(ad)} and I{sub (ad)}. TPD results show that the thermal decomposition of C{sub 2}D{sub 5(ad)} yields C{sub 2}D{sub 4} and D{sub 2} as the main products on both the surfaces. The main difference in the decomposition products of C{sub 2}D{sub 5(ad)} species on the two surfaces is that desorption of C{sub 2}D{sub 4} occurs on NiAl(111) at {approximately}315 K, {approximately}50 K higher than the corresponding value for NiAl(110). {copyright} {ital 1999 American Vacuum Society.}

Chaturvedi, S. [Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 (United States)] [Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973 (United States); Strongin, D.R. [Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States)] [Department of Chemistry, Temple University, Philadelphia, Pennsylvania 19122 (United States)

1999-05-01

278

Imaging the Ferron Member of the Mancos Shale formation using reprocessed high-resolution 2-D seismic reflection data: Emery County, Utah  

USGS Publications Warehouse

Late in 1982 and early in 1983, Arco Exploration contracted with Rocky Mountain Geophysical to acquired four high-resolution 2-D multichannel seismic reflection lines in Emery County, Utah. The primary goal in acquiring this data was an attempt to image the Ferron Member of the Upper Cretaceous Mancos Shale. Design of the high-resolution 2-D seismic reflection data acquisition used both a short geophone group interval and a short sample interval. An explosive energy source was used which provided an input pulse with broad frequency content and higher frequencies than typical non-explosive Vibroseis?? sources. Reflections produced by using this high-frequency energy source when sampled at a short interval are usually able to resolve shallow horizons that are relatively thin compared to those that can be resolved using more typical oil and gas exploration seismic reflection methods.The U.S. Geological Survey-Energy Resources Program, Geophysical Processing Group used the processing sequence originally applied by Arco in 1984 as a guide and experimented with processing steps applied in a different order using slightly different parameters in an effort to improve imaging the Ferron Member horizon. As with the Arco processed data there are sections along all four seismic lines where the data quality cannot be improved upon, and in fact the data quality is so poor that the Ferron horizon cannot be imaged at all.Interpretation of the seismic and core hole data indicates that the Ferron Member in the study area represent a deltaic sequence including delta front, lower delta plain, and upper delta plain environments. Correlating the depositional environments for the Ferron Member as indicated in the core holes with the thickness of Ferron Member suggests the presence of a delta lobe running from the northwest to the southeast through the study area. The presence of a deltaic channel system within the delta lobe complex might prove to be an interesting conventional exploration target along with the coal-bed methane production already proven in the area. ?? 2003 Elsevier B.V. All rights reserved.

Taylor, D.J.

2003-01-01

279

Strategies of statistical image analysis of 2D immunoblots: the case of IgG response in experimental Taenia crassiceps cysticercosis.  

PubMed

A procedure is described to measure the diversity and enrich the meaning and usefulness of the information contained in 2D immunoblot images of the reaction between a complex mixture of parasite antigens and the complex set of antibodies usually present in the sera of infected individual hosts. The procedure and results are illustrated by the experimental infection of 30 mice (three strains, both sexes, 5 mice in each strain x sex combination) with Taenia crassiceps cysticerci, thirty days after the challenge. The exercise revealed a significant positive correlation of parasite loads with the hosts' IgG response, in association with their genetic background and less clearly with their sex, all in the midst of a remarkable diversity of both response variables among individual mice. After superimposing a 10 x 10 grid upon the 2D immunoblots some 10% of the positive grid-cells (those who had at least one spot) were positively correlated, suggesting shared epitopes between different antigen spots and/or similar factors controlling different antibody-producing cell clones. Also, a significant correlation was found between many of the positive grid-cells with high values of [Sigma]parasites, but none with low. Thus, the procedure provided many clues for the selection of antigen spots useful to improve immunodiagnosis of cysticercosis and weakened the inclusion of any as vaccine candidate(s). However, some 16 antigen spots were shared almost exclusively by the resistant strains and could relate to protection. The procedure here illustrated may be used in other infections to assess and identify the relevance of antibodies in diagnosis and prevention, as well as provides a measurement of the expected diversity in the hosts' antibody response to the pathogen and of the possible relations between the individual responses towards different antigens contained in the mixture. PMID:19800348

Ostoa-Saloma, Pedro; Esquivel-Velázquez, Marcela; Ostoa-Jacobo, Pedro; Larralde, Carlos

2009-12-31

280

STP Ising 2D Program  

NSDL National Science Digital Library

The STP Ising2D program is a Monte Carlo simulation of a two-dimensional Ising model in equilibrium with a heat bath at temperature T using the Metropolis or Wolff algorithms. The default is a lattice of linear dimension L=32 (for a total of N=L^2 spins) with no external field and heat bath temperature T=0. STP Ising2D is part of a suite of Open Source Physics programs that model aspects of Statistical and Thermal Physics (STP). The program is distributed as a ready-to-run (compiled) Java archive. Double clicking the stp_Ising2D.jar file will run the program if Java is installed on your computer. Additional programs can be found by searching ComPADRE for Open Source Physics, STP, or Statistical and Thermal Physics.

Gould, Harvey; Tobochnik, Jan; Christian, Wolfgang; Cox, Anne

2008-05-28

281

JPEG2000 3D compression vs. 2D compression: an assessment of artifact amount and computing time in compressing thin-section abdomen CT images.  

PubMed

To assess the advantages of the Joint Photographic Experts Group (JPEG)2000 3D (part 2) over JPEG2000 in compressing thin-section abdomen CT data sets, 60 thin-section (0.67 mm) scans from 35 males and 25 females, ranging from 23 to 95 years of age (mean, 58 years), were compressed reversibly (as a negative control) and irreversibly to 4:1, 6:1, 8:1, 10:1, and 12:1 using JPEG2000 3D and JPEG2000 algorithms. Encoding and decoding times and peak signal-to-noise ratios (PSNRs) were measured. For 60 (one image per scan) representative sections containing abnormalities, three radiologists independently compared original and compressed images and graded compression artifacts as 0 (none, indistinguishable), 1 (barely perceptible), 2 (subtle), or 3 (significant). According to pooled radiologists' responses, the range of visually lossless threshold (VLT, the highest compression ratio at which a compressed image is indistinguishable from its original) was determined as one of <4:1, 4:1-6:1, 6:1-8:1, 8:1-10:1, 10:1-12:1, and >12:1. Wilcoxon signed rank tests and exact tests for paired proportions were used for the comparisons between the two compressions. At each irreversible compression ratio, compared to JPEG2000, JPEG2000 3D required two- or threefold greater computing times (p < 0.001) and introduced less artifacts in terms of PSNR (p <0.001) and the grade (p < 0.02 at 6:1 or higher) and the presence of perceived artifacts (p <0.008, at 6:1 for all readers and at 8:1 for two readers). According to PSNR and readers' responses, 6:1 and 8:1 JPEG2000 3D compressions showed more artifacts than 4:1 and 6:1 JPEG2000 compressions, respectively, and 10:1 and 12:1 JPEG2000 3D compressions showed similar artifacts to those of 8:1 and 10:1 JPEG2000 compressions, respectively. The determined VLT range was higher for JPEG2000 3D than for JPEG2000 (p < 0.001): the 3D compression showed the VLT ranges of 4:1-6:1, 6:1-8:1, and 8:1-10:1 for 24 (40%), 30 (50%), and 6 (10%) of the 60 original images, respectively, while the 2D compression showed the VLT ranges of <4:1, 4:1-6:1, and 6:1-8:1 for 1 (1.7%), 40 (66.7%), and 19 (31.6%) images, respectively. Compared to JPEG2000, JPEG2000 3D increased the VLT range in 23 of the 60 original images by one (n=22) or two ranges (n=1), while the remaining 37 images had the same VLT range between the two compressions. In conclusion, compared to JPEG2000 compression, JPEG2000 3D compression yields less artifacts in compressing thin-section abdomen CT images but requires significantly greater computing times. For the tested data set compressed to the range from 4:1 to 12:1, JPEG2000 3D could increase compression level reasonably (by 2 or less in terms of compression ratio) compared to JPEG2000 for the same amount of artifacts. PMID:19378744

Kim, Bohyoung; Lee, Kyoung Ho; Kim, Kil Joong; Richter, Thomas; Kang, Heung-Sik; Kim, So Yeon; Kim, Young Hoon; Seo, Jinwook

2009-03-01

282

Photoacoustic imaging and temperature measurement for photothermal cancer therapy  

PubMed Central

Photothermal therapy is a noninvasive, targeted, laser-based technique for cancer treatment. During photothermal therapy, light energy is converted to heat by tumor-specific photoabsorbers. The corresponding temperature rise causes localized cancer destruction. For effective treatment, however, the presence of photoabsorbers in the tumor must be ascertained before therapy and thermal imaging must be performed during therapy. This study investigates the feasibility of guiding photothermal therapy by using photoacoustic imaging to detect photoabsorbers and to monitor temperature elevation. Photothermal therapy is carried out by utilizing a continuous wave laser and metal nanocomposites broadly absorbing in the near-infrared optical range. A linear array-based ultrasound imaging system is interfaced with a nanosecond pulsed laser to image tissue-mimicking phantoms and ex-vivo animal tissue before and during photothermal therapy. Before commencing therapy, photoacoustic imaging identifies the presence and spatial location of nanoparticles. Thermal maps are computed by monitoring temperature-induced changes in the photoacoustic signal during the therapeutic procedure and are compared with temperature estimates obtained from ultrasound imaging. The results of our study suggest that photoacoustic imaging, augmented by ultrasound imaging, is a viable candidate to guide photoabsorber-enhanced photothermal therapy. PMID:18601569

Shah, Jignesh; Park, Suhyun; Aglyamov, Salavat; Larson, Timothy; Ma, Li; Sokolov, Konstantin; Johnston, Keith; Milner, Thomas; Emelianov, Stanislav Y.

2009-01-01

283

2D and 3D Electrical Resistivity Tomography imaging of earthquake related ground deformations at the Ancient Roman Forum and Isis Temple of Baelo Claudia (Cádiz, South Spain).  

NASA Astrophysics Data System (ADS)

The ancient roman city of Baelo Claudia has been subject of several papers on earthquake environmental effects (EEE) and well as earthquake archaeological effects (EAE). During the field training course on archaeoseismology and palaeoseismology conducted in September 2009 (INQUA-IGCP567 Workshop) held at Baelo Claudia, four Electric Resistivity Tomography (ERT) profiles were carried out, by the teams of the Salamanca University (Spain), RWTH Aachen University (Germany) and the Geological Survey of Spain (IGME). ERT surveys were developed in the eastern side of the ancient roman Forum across the unexcavated sector of the archaeological site heading on the 1st Century AD Isis Temple. Each ERT profile was constituted by a 48 multielectrode array with spacing of 2 m resulting in a total length of investigation of around 384 m. ERT lines were separated 10 m each other resulting in a total research area of 3840 m2 to a mean investigation depth of 16 m. The selected survey configurations were Pole-Dipole and Wenner in order to get detailed information about lateral resistivity contrasts, but with a reasonable depth of investigation. The resulting 2D resistivity pseudosections clearly display deformations of the buried roman pavements which propagated in depth within the pre-roman clayey substratum of the Bolonia Bay area.. 3D modelling of the 2D pseudosections indicates that the observed deformations are related to near-surface landsliding, being possible to calculate the minimum volume of mobilized material. ERT 3D imaging allow to refine previous GPR surveys conducted at this same area and to get a subsurface picture of ground deformations caused by repeated earthquakes during the 1st and 3rd Centuries AD. Preliminary calculated volume for the mobilized materials affecting the foundations of the Isis Temple and Forum clearly points to a minimum ESI-07 VIII Intensity validating previous research in the zone. This study has been supported by the Spanish Research Projects ACI2008-0276 (USAL), CGL08-03998BTE (USAL), CGL08-04000BTE (MNCN, CSIC)

Silva, Pablo G.

2010-05-01

284

Multimodal evaluation of 2-D and 3-D ultrasound, computed tomography and magnetic resonance imaging in measurements of the thyroid volume using universally applicable cross-sectional imaging software: a phantom study.  

PubMed

A precise estimate of thyroid volume is necessary for making adequate therapeutic decisions and planning, as well as for monitoring therapy response. The goal of this study was to compare the precision of different volumetry methods. Thyroid-shaped phantoms were subjected to volumetry via 2-D and 3-D ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI). The 3-D US scans were performed using sensor navigation and mechanical sweeping methods. Volumetry calculation ensued with the conventional ellipsoid model and the manual tracing method. The study confirmed the superiority of manual tracing with CT and MRI volumetry of the thyroid, but extended this knowledge also to the superiority of the 3-D US method, regardless of whether sensor navigation or mechanical sweeping is used. A novel aspect was successful use of the same universally applicable cross-imaging software for all modalities. PMID:24768486

Freesmeyer, Martin; Wiegand, Steffen; Schierz, Jan-Henning; Winkens, Thomas; Licht, Katharina

2014-07-01

285

Imaging the earth's magnetosphere - Effects of plasma flow and temperature  

NASA Technical Reports Server (NTRS)

The effects of Doppler shifting on the line centers of the magnetospheric O(+) cross section are investigated, and the resulting structure of the scattering rate as a function of bulk density is explained. Whereas the Doppler shifting frequently results in a decrease of the scattering rate, it is demonstrated that for certain drift speeds the overlap of the cross section and the solar intensity profile can lead to an increased rate, thus enhancing the relative brightness of the image above that obtained when v(p) is zero. Simulated images of the magnetosphere are obtained which are used to show quantitively how the magnetospheric image responds to variations in plasma drift speed and temperature. Changes in the brightness of the magnetospheric images also depend on the variability of the solar flux at 83.4 nm. In regions where there are plasma drifts, the brightness in the image is governed by the structure of the scattering rate, assuming a fixed temperature.

Garrido, D. E.; Smith, R. W.; Swift, D. S.; Akasofu, S.-I.

1991-01-01

286

Imaging transverse isotropic properties of muscle by monitoring acoustic radiation force induced shear waves using a 2-D matrix ultrasound array.  

PubMed

A 2-D matrix ultrasound array is used to monitor acoustic radiation force impulse (ARFI) induced shear wave propagation in 3-D in excised canine muscle. From a single acquisition, both the shear wave phase and group velocity can be calculated to estimate the shear wave speed (SWS) along and across the fibers, as well as the fiber orientation in 3-D. The true fiber orientation found using the 3-D radon transform on B-mode volumes of the muscle was used to verify the fiber direction estimated from shear wave data. For the simplified imaging case when the ARFI push can be oriented perpendicular to the fibers, the error in estimating the fiber orientation using phase and group velocity measurements was 3.5 ± 2.6° and 3.4 ± 1.4° (mean ± standard deviation), respectively, over six acquisitions in different muscle samples. For the more general case when the push is oblique to the fibers, the angle between the push and the fibers is found using the dominant orientation of the shear wave displacement magnitude. In 30 acquisitions on six different muscle samples with oblique push angles up to 40°, the error in the estimated fiber orientation using phase and group velocity measurements was 5.4 ± 2.9° and 5.3 ± 3.2°, respectively, after estimating and accounting for the additional unknown push angle. Either the phase or group velocity measurements can be used to estimate fiber orientation and SWS along and across the fibers. Although it is possible to perform these measurements when the push is not perpendicular to the fibers, highly oblique push angles induce lower shear wave amplitudes which can cause inaccurate SWS measurements. PMID:23686942

Wang, Michael; Byram, Brett; Palmeri, Mark; Rouze, Ned; Nightingale, Kathryn

2013-09-01

287

Imaging Transverse Isotropic Properties of Muscle by Monitoring Acoustic Radiation Force Induced Shear Waves using a 2D Matrix Ultrasound Array  

PubMed Central

A 2D matrix ultrasound array is used to monitor acoustic radiation force impulse (ARFI) induced shear wave propagation in 3D in excised canine muscle. From a single acquisition, both the shear wave phase and group velocity can be calculated to estimate the shear wave speed (SWS) along and across the fibers, as well as the fiber orientation in 3D. The true fiber orientation found using the 3D Radon Transform on B-mode volumes of the muscle was used to verify the fiber direction estimated from shear wave data. For the simplified imaging case when the ARFI push can be oriented perpendicular to the fibers, the error in estimating the fiber orientation using phase and group velocity measurements was 3.5 ±2.6° and 3.4 ±1.4° (mean ± standard deviation), respectively, over six acquisitions in different muscle samples. For the more general case when the push is oblique to the fibers, the angle between the push and the fibers is found using the dominant orientation of the shear wave displacement magnitude. In 30 acquisitions on six different muscle samples with oblique push angles up to 40°, the error in the estimated fiber orientation using phase and group velocity measurements was 5.4±2.9° and 5.3±3.2°, respectively, after estimating and accounting for the additional unknown push angle. Either the phase or group velocity measurements can be used to estimate fiber orientation and SWS along and across the fibers. Although it is possible to perform these measurements when the push is not perpendicular to the fibers, highly oblique push angles induce lower shear wave amplitudes which can cause inaccurate SWS measurements. PMID:23686942

Wang, Michael; Byram, Brett; Palmeri, Mark; Rouze, Ned; Nightingale, Kathryn

2013-01-01

288

A COMPARISON OF 2D IMAGE ANALYSIS AND DESIGN-BASED STEREOLOGY FOR EVALUATING MORPHOLOGICAL AND ANATOMICAL CHANGES IN THE DOPAMINERGIC SYSTEM OF THE RODENT MIDBRAIN  

E-print Network

Background. 2D analyses produce systematic errors in quantifying anatomical and morphological features in the brain. Design-based stereology overcomes this limitation by applying probability theory, yet many neuroscience ...

Park, Ji-Hyuk

2010-06-13

289

A Method to Convert MRI Images of Temperature Change Into Images of Absolute Temperature in Solid Tumors  

PubMed Central

Purpose During hyperthermia (HT), the therapeutic response of tumors varies substantially within the target temperature range (39–43°C). Current thermometry methods are either invasive or measure only temperature change, which limits the ability to study tissue responses to HT. This study combines manganese-containing low-temperature sensitive liposomes (Mn-LTSL) with proton resonance frequency shift (PRFS) thermometry to measure absolute temperature in tumors with high spatial and temporal resolution using MRI. Methods Liposomes were loaded with 300mM MnSO4. The phase transition temperature (Tm) of Mn-LTSL samples was measured by differential scanning calorimetry (DSC). The release of manganese from Mn-LTSL in saline was characterized with inductively-coupled plasma atomic emission spectroscopy. A 2T GE small animal scanner was used to acquire dynamic T1-weighted images and temperature change images of Mn-LTSL in saline phantoms and fibrosarcoma-bearing Fisher 344 rats receiving hyperthermia after Mn-LTSL injection. Results The Tm of Mn-LTSL in rat blood was 42.9 ± 0.2 °C (DSC). For Mn-LTSL samples (0.06mM – 0.5mM Mn2+ in saline) heated monotonically from 30°C to 50°C, a peak in the rate of MRI signal enhancement occurred at 43.1 ± 0.3 °C. The same peak in signal enhancement rate was observed during heating of fibrosarcoma tumors (N=3) after injection of Mn-LTSL, and the peak was used to convert temperature change images into absolute temperature. Accuracies of calibrated temperature measurements were in the range 0.9 – 1.8°C. Conclusion The release of Mn2+ from Mn-LTSL affects the rate of MR signal enhancement which enables conversion of MRI-based temperature change images to absolute temperature. PMID:23957326

Davis, Ryan M.; Viglianti, Benjamin L.; Yarmolenko, Pavel; Park, Ji-Young; Stauffer, Paul; Needham, David; Dewhirst, Mark W.

2013-01-01

290

Interactive Transformation of 2D Vector Data Eduard Grller  

E-print Network

shape. The presented program enables the investigation of 2D cross­sections of, e.g., insect bodies restricts himself to 2D transformations. The manipulation, distortion and transformation of 2D raster image data has become quite popular in computer graphics in recent years. [2] deals with image warping which

291

USE OF THE ELASTOPLASTIC 1D BEAM ELEMENT TO EVALUATE THE LIMIT BEHAVIOUR OF 2D STEEL FRAMES UNDER ELEVATED TEMPERATURES  

Microsoft Academic Search

Summary. A general procedure is presented to evaluate the limit behaviour in the 2D elastoplastic beam element under static forces and thermal loading. We assume the Navier hypothesis for beams and sudden and concentrated plasticity in the beam-ends attending the yield function Y based on the von Mises criterion. Results illustrate that in a beam with plastic behaviour the fixed-end

Antolín L. Ibán; José M. García-Terán

292

Please cite this article in press as: C. Zohios, et al., Geometrical methods for level set based abdominal aortic aneurysm thrombus and outer wall 2D image segmentation, Comput. Methods Programs Biomed. (2011), doi:10.1016/j.cmpb.2011.06.009  

E-print Network

abdominal aortic aneurysm thrombus and outer wall 2D image segmentation, Comput. Methods Programs Biomed.intl.elsevierhealth.com/journals/cmpb Geometrical methods for level set based abdominal aortic aneurysm thrombus and outer wall 2D image form 9 December 2010 Accepted 28 June 2011 Keywords: Abdominal aortic aneurysm Level Set Methods

Papaharilaou, Yannis

293

Imaging of the surface resistance of an SRF cavity by low-temperature laser scanning microscopy  

SciTech Connect

Temperature mapping of the outer surface of a superconducting radio-frequency cavity is a technique that is often used to identify lossy areas on the cavity surface. In this contribution, we present 2-D images of the superconducting state surface resistance R{sub s} of the inner surface of a superconducting radio-frequency (SRF) cavity obtained by low-temperature laser scanning microscopy. This technique, which is applied for the first time to study lossy regions in an operating SRF cavity, allows identifying 'hotspots' with about one order of magnitude better spatial resolution ( ~2 mm) than by thermometry. The R{sub s}-resolution is of the order of 1 {micro}{Ohm} at 3.3 GHz. Surface resistance maps with different laser power and optical images of the cavity surface are discussed in this contribution. It is also shown that the thermal gradient on the niobium surface created by the laser beam can move some of the hotspots, which are identified as locations of trapped bundle of fluxoids. The prospects for this microscope to identify defects that limit the performance of SRF cavities will also be discussed.

G. Ciovati, S.M. Anlage, A.V. Gurevich

2013-06-01

294

2D Face Recognition  

Microsoft Academic Search

\\u000a An overview of selected topics in face recognition is first presented in this chapter. The BioSecure 2D-face Benchmarking\\u000a Framework is also described, composed of open-source software, publicly available databases and protocols. Three methods for\\u000a 2D-face recognition, exploiting multiscale analysis, are presented. The first method exploits anisotropic smoothing, combined\\u000a Gabor features and Linear Discriminant Analysis (LDA). The second approach is based

Massimo Tistarelli; Manuele Bicego; José L. Alba-Castro; Daniel Gonzàlez-Jiménez; Mohamed-Anouar Mellakh; Albert Ali Salah; Dijana Petrovska-Delacrétaz; Bernadette Dorizzi; G. Chollet

2008-01-01

295

Global surface temperature/heat transfer measurements using infrared imaging  

NASA Technical Reports Server (NTRS)

A series of studies were conducted to evaluate the use of scanning radiometric infrared imaging systems for providing global surface temperature/heat transfer measurements in support of hypersonic wind tunnel testing. The in situ precision of the technique with narrow temperature span setting over the temperature range of 20 to 200 C was investigated. The precision of the technique over wider temperature span settings was also determined. The accuracy of technique for providing aerodynamic heating rates was investigated by performing measurements on a 10.2-centimeter hemisphere model in the Langley 31-inch Mach 10 tunnel, and comparing the results with theoretical predictions. Data from tests conducted on a generic orbiter model in this tunnel are also presented.

Daryabeigi, Kamran

1992-01-01

296

Rapid 2D-to-3D conversion  

Microsoft Academic Search

The conversion of existing 2D images to 3D is proving commercially viable and fulfills the growing need for high quality stereoscopic images. This approach is particularly effective when creating content for the new generation of autostereoscopic displays that require multiple stereo images. The dominant technique for such content conversion is to develop a depth map for each frame of 2D

Philip V. Harman; Julien Flack; Simon Fox; Mark Dowley

2002-01-01

297

Microwave Imager Measures Sea Surface Temperature Through Clouds  

NASA Technical Reports Server (NTRS)

This image was acquired over Tropical Atlantic and U.S. East Coast regions on Aug. 22 - Sept. 23, 1998. Cloud data were collected by the Geostationary Operational Environmental Satellite (GOES). Sea Surface Temperature (SST) data were collected aboard the NASA/NASDA Tropical Rainfall Measuring Mission (TRMM) satellite by The TRMM Microwave Imager (TMI). TMI is the first satellite microwave sensor capable of accurately measuring sea surface temperature through clouds, as shown in this scene. For years scientists have known there is a strong correlation between sea surface temperature and the intensity of hurricanes. But one of the major stumbling blocks for forecasters has been the precise measurement of those temperatures when a storm begins to form. In this scene, clouds have been made translucent to allow an unobstructed view of the surface. Notice Hurricane Bonnie approaching the Carolina Coast (upper left) and Hurricane Danielle following roughly in its path (lower right). The ocean surface has been falsely colored to show a map of water temperature--dark blues are around 75oF, light blues are about 80oF, greens are about 85oF, and yellows are roughly 90oF. A hurricane gathers energy from warm waters found at tropical latitudes. In this image we see Hurricane Bonnie cross the Atlantic, leaving a cooler trail of water in its wake. As Hurricane Danielle followed in Bonnie's path, the wind speed of the second storm dropped markedly, as available energy to fuel the storm dropped off. But when Danielle left Bonnie's wake, wind speeds increased due to temperature increases in surface water around the storm. As a hurricane churns up the ocean, it's central vortex draws surface heat and water into the storm. That suction at the surface causes an upwelling of deep water. At depth, tropical ocean waters are significantly colder than water found near the surface. As they're pulled up to meet the storm, those colder waters essentially leave a footprint in the storm's wake which might last as long as two weeks. Forecasters can quantify the difference in surface temperatures between this footprint and the surrounding temperatures and use that information to better predict storm intensity. If another storm intersects with this cold water trail, it is likely to lose significant strength due to the fact that the colder water does not contain as much potential energy as warm water. TRMM Fact Sheet Predicting Hurricane Intensity Far from Land Remote Sensing Systems Image courtesy TRMM Project, Remote Sensing Systems, and Scientific Visualization Studio, NASA Goddard Space Flight Center

2002-01-01

298

2D OSCILLATING HYDROFOIL  

Microsoft Academic Search

This paper presents a validation of numerical simulations in case of a forced oscillating hydrofoil. As a representative case study for vibrating blade in hydraulics machines, a 2D NACA 0009 oscillating hydrofoil is considered. Pressure coefficients from experiments and numerical simulations are presented. The fluid torque is then investigated in the frequency domain. A good agreement between experiments and numerical

Cecile MÜNCH; Philippe AUSONI; Mohamed FARHAT; François AVELLAN

299

Luminescence imaging for aerodynamic temperature and pressure measurements  

SciTech Connect

A luminescent temperature sensitive paint containing the molecule rhodamine B base (rhBb) is described whose emission intensity can be monitored by video camera to produce qualitative and quantitative two dimensional surface temperature maps. This paint was designed for use with the pressure sensitive paint containing platinum octaethylporphyrin (PtOEP), but is also a useful tool when used alone in the measurement of heat flow, boundary layer transition, and quantitative surface temperature during wind tunnel studies. The ability of the rhBb paint to produce a continuous temperature map makes it possible to locate structures in the temperature field on an airfoil that are otherwise undetected by surface mounted thermocouples spaced a finite distance apart. A dual temperature/pressure sensitive paint was investigated with both the rhBb and PtOEP dyes incorporated into the silicone polymer paint base of the pressure sensor. Photodegradation and batch variations in the polymer were found to compromise the calibration parameters of the PtOEP paint and therefore the accuracy of pressure predictions. Suggestions are made for improving the prediction ability of the paint. The molecule europium(III) thenoyltrifluoroacetonate (EuTTA) is also discussed as a temperature sensor for a two layer temperature/pressure paint. EuTTA can not be directly incorporated into the silicone paint base of the PtOEP paint (as the rhBp paint can), but performs well in non-oxygenpermeable coatings. Benefits of the EuTTA temperature paint include: (1) decreased photodegradation, (2) very bright luminescence intensity, and (3) long luminescent lifetime (several hundred microseconds). The long lifetime facilitates lifetime imaging, a technique currently under development as an alternative detection method where luminescent lifetimes rather than emission intensity are related to temperature and pressure.

Gallery, J.M.

1993-01-01

300

Meniscal Calcifications: Morphologic and Quantitative Evaluation by using 2D Inversion-Recovery Ultrashort Echo Time and 3D Ultrashort Echo Time 3.0-T MR Imaging Techniques—Feasibility Study  

PubMed Central

Purpose: To assess the ability of ultrashort echo time (UTE) magnetic resonance (MR) imaging techniques to enable morphologic assessment of different types of meniscal calcifications, to compare these sequences with standard clinical sequences, and to perform T2* measurements of meniscal calcifications. Materials and Methods: This study was exempted by the institutional review board, and informed consent was not required. Ten human cadaveric menisci were imaged with high-spatial-resolution radiography and 3.0-T MR imaging by using morphologic (T1-weighted fast spin-echo [FSE], T2-weighted FSE, proton density [PD]-weighted FSE, two-dimensional [2D] fast spoiled gradient-echo [FSPGR], three-dimensional [3D] FSPGR, and 3D UTE) and quantitative (2D inversion-recovery [IR] UTE and 3D UTE) sequences. The menisci were divided into thirds for regional analysis. Morphologic assessment was performed with MR imaging; MR imaging findings were correlated with radiographs. Calcifications were classified as punctate, linear, or globular. T2* measurements were performed by manual placement of regions of interest (ROIs) in calcifications and by automatically creating ROIs in the surrounding tissues. Mixed-effects linear regression was used to determine variations in T2* as a function of region, morphology, and tissue type. Results: The two globular calcifications were visualized with all sequences. For punctate (n = 21) and linear (n = 21) calcifications, respectively, visibility rates were as follows: 9.5% for both with the T1-weighted FSE sequence, 0% for both with the T2-weighted FSE sequence, 19.0% and 23.8% with the PD-weighted FSE sequence, 0% for both with the 2D IR UTE sequence, 100% for both with the 3D UTE sequence, and 100% for both with the 3D FSPGR sequence. T2* values were significantly lower for calcifications than for the surrounding meniscal tissue (P < .001). There was a trend of globular calcifications having lower T2* values than other morphologies (P = .08). With the 2D IR UTE technique, the T2* of the globular calcifications tended to be lower than with the 3D UTE technique (0.13–0.16 vs 1.32–3.03 msec) (P = .14, analysis of variance). Conclusion: UTE MR imaging sequences may allow morphologic as well as quantitative evaluation of meniscal calcifications. © RSNA, 2012 PMID:22723564

Omoumi, Patrick; Bae, Won C.; Du, Jiang; Diaz, Eric; Statum, Sheronda; Bydder, Graeme M.

2012-01-01

301

Kalman Filtered MR Temperature Imaging for Laser Induced Thermal Therapies  

PubMed Central

The feasibility of using a stochastic form of Pennes bioheat model within a 3D finite element based Kalman filter (KF) algorithm is critically evaluated for the ability to provide temperature field estimates in the event of magnetic resonance temperature imaging (MRTI) data loss during laser induced thermal therapy (LITT). The ability to recover missing MRTI data was analyzed by systematically removing spatiotemporal information from a clinical MR-guided LITT procedure in human brain and comparing predictions in these regions to the original measurements. Performance was quantitatively evaluated in terms of a dimensionless L2 (RMS) norm of the temperature error weighted by acquisition uncertainty. During periods of no data corruption, observed error histories demonstrate that the Kalman algorithm does not alter the high quality temperature measurement provided by MR thermal imaging. The KF-MRTI implementation considered is seen to predict the bioheat transfer with RMS error < 4 for a short period of time, ?t < 10sec, until the data corruption subsides. In its present form, the KF-MRTI method currently fails to compensate for consecutive for consecutive time periods of data loss ?t > 10sec. PMID:22203706

Fuentes, D.; Yung, J.; Hazle, J. D.; Weinberg, J. S.; Stafford, R. J.

2013-01-01

302

Temperature rise and safety considerations for radiation force ultrasound imaging  

NASA Astrophysics Data System (ADS)

Current models for estimating temperature increase during ultrasound exposure calculate the steady-state rise, using time-averaged acoustic output, as the worst case for safety consideration. While valid for the typically very short (microsecond) pulses used by conventional diagnostic techniques, this analysis does not necessarily correspond to a worst case scenario for the longer pulses or pulse bursts used by a new method, radiation force imaging. Radiation force imaging, employing ultrasound pulse durations up to hundreds of milliseconds, produces and detects motion in solid tissue or acoustic streaming in fluids via a high intensity beam. Models that calculate the transient temperature rise from these pulses are developed for both the bone at focus and soft tissue cases. Based on accepted time-temperature dose criteria, it is shown that for pulse lengths and intensities utilized by this technique, temperature may increase to levels that raise safety concerns for bone at the focus of the ultrasound beam. Also, the impact on this modality of the current U.S. Food and Drug Administration output limits for diagnostic ultrasound devices is discussed.

Herman, Bruce A.; Harris, Gerald R.

2002-11-01

303

GCA in 2d  

NASA Astrophysics Data System (ADS)

We make a detailed study of the infinite dimensional Galilean Conformal Algebra (GCA) in the case of two spacetime dimensions. Classically, this algebra is precisely obtained from a contraction of the generators of the relativistic conformal symmetry in 2 d. Here we find quantum mechanical realisations of the (centrally extended) GCA by considering scaling limits of certain 2d CFTs. These parent CFTs are non-unitary and have their left and right central charges become large in magnitude and opposite in sign. We therefore develop, in parallel to the usual machinery for 2 d CFT, many of the tools for the analysis of the quantum mechanical GCA. These include the representation theory based on GCA primaries, Ward identities for their correlation functions and a nonrelativistic Kac table. In particular, the null vectors of the GCA lead to differential equations for the four point function. The solution to these equations in the simplest case is explicitly obtained and checked to be consistent with various requirements.

Bagchi, Arjun; Gopakumar, Rajesh; Mandal, Ipsita; Miwa, Akitsugu

2010-08-01

304

Finite Heat conduction in 2D Lattices  

E-print Network

This paper gives a 2D hamonic lattices model with missing bond defects, when the capacity ratio of defects is enough large, the temperature gradient can be formed and the finite heat conduction is found in the model. The defects in the 2D harmonic lattices impede the energy carriers free propagation, by another words, the mean free paths of the energy carrier are relatively short. The microscopic dynamics leads to the finite conduction in the model.

Lei Yang; Yang Kongqing

2001-07-30

305

Flip Angle Profile Correction for T1 and T2 Quantification with Look-Locker Inversion Recovery 2D SSFP Imaging  

PubMed Central

Fast methods using balanced steady-state free precession (SSFP) have been developed to reduce the scan time of T1 and T2 mapping. However, flip angle (FA) profiles created by the short RF pulses used in SSFP deviate substantially from the ideal rectangular profile, causing T1 and T2 mapping errors. The purpose of this study was to develop a FA profile correction for T1 and T2 mapping with Look-Locker 2D inversion recovery SSFP and to validate this method using 2D spin echo as a reference standard. Phantom studies showed consistent improvement in T1 and T2 accuracy using profile correction at multiple FAs. Over six human calves, profile correction provided muscle T1 estimates with mean error ranging from excellent (?0.6%) at TR/FA = 18 ms/60° to acceptable (6.8%) at TR/FA = 4.9 ms/30°, while muscle T2 estimates were less accurate with mean errors of 31.2% and 47.9%, respectively. PMID:22294428

Cooper, Mitchell A.; Nguyen, Thanh D.; Spincemaille, Pascal; Prince, Martin R.; Weinsaft, Jonathan W.; Wang, Yi

2011-01-01

306

Resonant tunneling modulation in quasi-2D Cu(2)O/SnO(2) p-n horizontal-multi-layer heterostructure for room temperature H(2)S sensor application.  

PubMed

Heterostructure material that acts as resonant tunneling system is a major scientific challenge in applied physics. Herein, we report a resonant tunneling system, quasi-2D Cu(2)O/SnO(2) p-n heterostructure multi-layer film, prepared by electrochemical deposition in a quasi-2D ultra-thin liquid layer. By applying a special half-sine deposition potential across the electrodes, Cu(2)O and SnO(2) selectively and periodically deposited according to their reduction potentials. The as-prepared heterostructure film displays excellent sensitivity to H(2)S at room temperature due to the resonant tunneling modulation. Furthermore, it is found that the laser illumination could enhance the gas response, and the mechanism with laser illumination is discussed. It is the first report on gas sensing application of resonant tunneling modulation. Hence, heterostructure material act as resonant tunneling system is believed to be an ideal candidate for further improvement of room temperature gas sensing. PMID:23409241

Cui, Guangliang; Zhang, Mingzhe; Zou, Guangtian

2013-01-01

307

Resonant tunneling modulation in quasi-2D Cu2O/SnO2 p-n horizontal-multi-layer heterostructure for room temperature H2S sensor application  

PubMed Central

Heterostructure material that acts as resonant tunneling system is a major scientific challenge in applied physics. Herein, we report a resonant tunneling system, quasi-2D Cu2O/SnO2 p-n heterostructure multi-layer film, prepared by electrochemical deposition in a quasi-2D ultra-thin liquid layer. By applying a special half-sine deposition potential across the electrodes, Cu2O and SnO2 selectively and periodically deposited according to their reduction potentials. The as-prepared heterostructure film displays excellent sensitivity to H2S at room temperature due to the resonant tunneling modulation. Furthermore, it is found that the laser illumination could enhance the gas response, and the mechanism with laser illumination is discussed. It is the first report on gas sensing application of resonant tunneling modulation. Hence, heterostructure material act as resonant tunneling system is believed to be an ideal candidate for further improvement of room temperature gas sensing. PMID:23409241

Cui, Guangliang; Zhang, Mingzhe; Zou, Guangtian

2013-01-01

308

Spacecraft design project: High temperature superconducting infrared imaging satellite  

NASA Technical Reports Server (NTRS)

The High Temperature Superconductor Infrared Imaging Satellite (HTSCIRIS) is designed to perform the space based infrared imaging and surveillance mission. The design of the satellite follows the black box approach. The payload is a stand alone unit, with the spacecraft bus designed to meet the requirements of the payload as listed in the statement of work. Specifications influencing the design of the spacecraft bus were originated by the Naval Research Lab. A description of the following systems is included: spacecraft configuration, orbital dynamics, radio frequency communication subsystem, electrical power system, propulsion, attitude control system, thermal control, and structural design. The issues of testing and cost analysis are also addressed. This design project was part of the course Advanced Spacecraft Design taught at the Naval Postgraduate School.

1991-01-01

309

Comparison of 2D and 3D Imaging and Treatment Planning for Postoperative Vaginal Apex High-Dose Rate Brachytherapy for Endometrial Cancer  

SciTech Connect

Purpose: To evaluate bladder and rectal doses using two-dimensional (2D) and 3D treatment planning for vaginal cuff high-dose rate (HDR) in endometrial cancer. Methods and Materials: Ninety-one consecutive patients treated between 2000 and 2007 were evaluated. Seventy-one and 20 patients underwent 2D and 3D planning, respectively. Each patient received six fractions prescribed at 0.5 cm to the superior 3 cm of the vagina. International Commission on Radiation Units and Measurements (ICRU) doses were calculated for 2D patients. Maximum and 2-cc doses were calculated for 3D patients. Organ doses were normalized to prescription dose. Results: Bladder maximum doses were 178% of ICRU doses (p < 0.0001). Two-cubic centimeter doses were no different than ICRU doses (p = 0.22). Two-cubic centimeter doses were 59% of maximum doses (p < 0.0001). Rectal maximum doses were 137% of ICRU doses (p < 0.0001). Two-cubic centimeter doses were 87% of ICRU doses (p < 0.0001). Two-cubic centimeter doses were 64% of maximum doses (p < 0.0001). Using the first 1, 2, 3, 4 or 5 fractions, we predicted the final bladder dose to within 10% for 44%, 59%, 83%, 82%, and 89% of patients by using the ICRU dose, and for 45%, 55%, 80%, 85%, and 85% of patients by using the maximum dose, and for 37%, 68%, 79%, 79%, and 84% of patients by using the 2-cc dose. Using the first 1, 2, 3, 4 or 5 fractions, we predicted the final rectal dose to within 10% for 100%, 100%, 100%, 100%, and 100% of patients by using the ICRU dose, and for 60%, 65%, 70%, 75%, and 75% of patients by using the maximum dose, and for 68%, 95%, 84%, 84%, and 84% of patients by using the 2-cc dose. Conclusions: Doses to organs at risk vary depending on the calculation method. In some cases, final dose accuracy appears to plateau after the third fraction, indicating that simulation and planning may not be necessary in all fractions. A clinically relevant level of accuracy should be determined and further research conducted to address this issue.

Russo, James K. [Department of Radiation Oncology, Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina (United States); Armeson, Kent E. [Division of Biostatistics and Epidemiology, Hollings Cancer Center, Medical University of South Carolina, Charleston, South Carolina (United States); Richardson, Susan, E-mail: srichardson@radonc.wustl.edu [Department of Radiation Oncology, Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri (United States)

2012-05-01

310

Temperature-driven disorder–order transitions in 2D copper-intercalated MoO3 revealed using dynamic transmission electron microscopy  

NASA Astrophysics Data System (ADS)

We demonstrate two different classes of disorder–order phase transitions in two-dimensional layered nanomaterial MoO3 intercalated with ?9–15 atomic percent zero-valent copper using conventional in situ electron diffraction and dynamic transmission electron microscopy. Heating to ?325 °C on a time scale of minutes produces a superlattice consistent with the formation of a charge density wave stabilized by nanometer-scale ordering of the copper intercalant. Unlike conventional purely electronic charge-density-wave states which form, reform, and disappear on picosecond scales as the temperature is changed, once it forms the observed structure in Cu–MoO3 is stable indefinitely over a very large temperature range (30 °C to the decomposition temperature of 450 °C). Nanosecond-scale heating to ?380–400 °C produced a completely different structure, replacing the disordered as-fabricated Cu–MoO3 with a much more crystallographically ordered metastable state that, according to a precession electron diffraction reconstruction, resembles the original MoO3 lattice apart from an asymmetric distortion that appears to expand parts of the van der Waals gaps to accommodate the copper intercalant. Control experiments in Cu-free material exhibited neither transformation, thus it appears the copper is a necessary part of the phase dynamics. This work shows how the combination of high-density metal atom intercalation and heat treatment over a wide range of time scales can produce nanomaterials of high crystalline quality in unique structural states that cannot be accessed through other methods.

Reed, Bryan W.; Chung, Frank R.; Wang, Mengjing; LaGrange, Thomas; Koski, Kristie J.

2014-12-01

311

Definitions for a Common Standard for 2D Speckle Tracking Echocardiography: Consensus Document of the EACVI/ASE/Industry Task Force to Standardize Deformation Imaging.  

PubMed

Recognizing the critical need for standardization in strain imaging, in 2010, the European Association of Echocardiography (now the European Association of Cardiovascular Imaging, EACVI) and the American Society of Echocardiography (ASE) invited technical representatives from all interested vendors to participate in a concerted effort to reduce intervendor variability of strain measurement. As an initial product of the work of the EACVI/ASE/Industry initiative to standardize deformation imaging, we prepared this technical document which is intended to provide definitions, names, abbreviations, formulas, and procedures for calculation of physical quantities derived from speckle tracking echocardiography and thus create a common standard. PMID:25623220

Voigt, Jens-Uwe; Pedrizzetti, Gianni; Lysyansky, Peter; Marwick, Tom H; Houle, Hélène; Baumann, Rolf; Pedri, Stefano; Ito, Yasuhiro; Abe, Yasuhiko; Metz, Stephen; Song, Joo Hyun; Hamilton, Jamie; Sengupta, Partho P; Kolias, Theodore J; d'Hooge, Jan; Aurigemma, Gerard P; Thomas, James D; Badano, Luigi Paolo

2015-02-01

312

Development and Implementation of a Web-Enabled 3D Consultation Tool for Breast Augmentation Surgery Based on 3D-Image Reconstruction of 2D Pictures  

PubMed Central

Background Producing a rich, personalized Web-based consultation tool for plastic surgeons and patients is challenging. Objective (1) To develop a computer tool that allows individual reconstruction and simulation of 3-dimensional (3D) soft tissue from ordinary digital photos of breasts, (2) to implement a Web-based, worldwide-accessible preoperative surgical planning platform for plastic surgeons, and (3) to validate this tool through a quality control analysis by comparing 3D laser scans of the patients with the 3D reconstructions with this tool from original 2-dimensional (2D) pictures of the same patients. Methods The proposed system uses well-established 2D digital photos for reconstruction into a 3D torso, which is then available to the user for interactive planning. The simulation is performed on dedicated servers, accessible via Internet. It allows the surgeon, together with the patient, to previsualize the impact of the proposed breast augmentation directly during the consultation before a surgery is decided upon. We retrospectively conduced a quality control assessment of available anonymized pre- and postoperative 2D digital photographs of patients undergoing breast augmentation procedures. The method presented above was used to reconstruct 3D pictures from 2D digital pictures. We used a laser scanner capable of generating a highly accurate surface model of the patient’s anatomy to acquire ground truth data. The quality of the computed 3D reconstructions was compared with the ground truth data used to perform both qualitative and quantitative evaluations. Results We evaluated the system on 11 clinical cases for surface reconstructions and 4 clinical cases of postoperative simulations, using laser surface scan technologies showing a mean reconstruction error between 2 and 4 mm and a maximum outlier error of 16 mm. Qualitative and quantitative analyses from plastic surgeons demonstrate the potential of these new emerging technologies. Conclusions We tested our tool for 3D, Web-based, patient-specific consultation in the clinical scenario of breast augmentation. This example shows that the current state of development allows for creation of responsive and effective Web-based, 3D medical tools, even with highly complex and time-consuming computation, by off-loading them to a dedicated high-performance data center. The efficient combination of advanced technologies, based on analysis and understanding of human anatomy and physiology, will allow the development of further Web-based reconstruction and predictive interfaces at different scales of the human body. The consultation tool presented herein exemplifies the potential of combining advancements in the core areas of computer science and biomedical engineering with the evolving areas of Web technologies. We are confident that future developments based on a multidisciplinary approach will further pave the way toward personalized Web-enabled medicine. PMID:22306688

Garcia, Jaime; Olariu, Radu; Dindoyal, Irving; Le Huu, Serge

2012-01-01

313

Computed tomography imaging spectrometer (CTIS) with 2D reflective grating for ultraviolet to long-wave infrared detection especially useful for surveying transient events  

NASA Technical Reports Server (NTRS)

The optical system of this invention is an unique type of imaging spectrometer, i.e. an instrument that can determine the spectra of all points in a two-dimensional scene. The general type of imaging spectrometer under which this invention falls has been termed a computed-tomography imaging spectrometer (CTIS). CTIS's have the ability to perform spectral imaging of scenes containing rapidly moving objects or evolving features, hereafter referred to as transient scenes. This invention, a reflective CTIS with an unique two-dimensional reflective grating, can operate in any wavelength band from the ultraviolet through long-wave infrared. Although this spectrometer is especially useful for rapidly occurring events it is also useful for investigation of some slow moving phenomena as in the life sciences.

Wilson, Daniel W. (Inventor); Maker, Paul D. (Inventor); Muller, Richard E. (Inventor); Mouroulis, Pantazis Z. (Inventor)

2003-01-01

314

A 2D Human Body Model Dressed in Eigen Clothing  

E-print Network

A 2D Human Body Model Dressed in Eigen Clothing Peng Guan Oren Freifeld Michael J. Black estimation of people in monocular images are widely studied. Two-dimensional mod- els of the human body. The resulting generative model captures realistic human forms in monocular images and is used to infer 2D body

Black, Michael J.

315

Improving the image discontinuous problem by using color temperature mapping method  

NASA Astrophysics Data System (ADS)

This article mainly focuses on image processing of radial imaging capsule endoscope (RICE). First, it used the radial imaging capsule endoscope (RICE) to take the images, the experimental used a piggy to get the intestines and captured the images, but the images captured by RICE were blurred due to the RICE has aberration problems in the image center and lower light uniformity affect the image quality. To solve the problems, image processing can use to improve it. Therefore, the images captured by different time can use Person correlation coefficient algorithm to connect all the images, and using the color temperature mapping way to improve the discontinuous problem in the connection region.

Jeng, Wei-De; Mang, Ou-Yang; Lai, Chien-Cheng; Wu, Hsien-Ming

2011-09-01

316

Calibration of water proton chemical shift with temperature for noninvasive temperature imaging during focused ultrasound surgery.  

PubMed

The present work was performed to calibrate water proton chemical shift change with tissue temperature in vivo to establish a method of quantitative temperature imaging during focused ultrasound surgery. The chemical shift change measured with a phase-mapping method using spoiled gradient-recalled acquisition in steady state (SPGR) (TR = 26 msec, TE = 12.8 msec, matrix = 256 x 128) was calibrated with the corresponding temperature elevation (0-50 degrees C, 32-84 degrees C in absolute temperature) measured with a copper-constantan thermocouple (.05-mm-diameter bare wires) in rabbit skeletal muscle (16 animals) under focused ultrasound exposures (10-100 W radiofrequency [RF] power, 20-second sonication). A linear calibration with a regression coefficient of (-8.76+/-.69) x 10(-3) ppm/degrees C (P < .01 [P, significance level]) was obtained. Temperature distributions during a 20-second sonication were visualized every 3.3 seconds with a 2.3-mm3 spatial resolution and 4 degrees C temperature uncertainty. PMID:9500277

Kuroda, K; Chung, A H; Hynynen, K; Jolesz, F A

1998-01-01

317

Low-Temperature Scanning Capacitance Probe for Imaging Electron Motion  

NASA Astrophysics Data System (ADS)

Novel techniques to probe electronic properties at the nanoscale can shed light on the physics of nanoscale devices. In particular, studying the scattering of electrons from edges and apertures at the nanoscale and imaging the electron profile in a quantum dot, have been of interest [1]. In this paper, we present the design and implementation of a cooled scanning capacitance probe that operates at liquid He temperatures to image electron waves in nanodevices. The conducting tip of a scanned probe microscope is held above the nanoscale structure, and an applied sample-to-tip voltage creates an image charge that is measured by a cooled charge amplifier [2] adjacent to the tip. The circuit is based on a low-capacitance, high- electron-mobility transistor (Fujitsu FHX35X). The input is a capacitance bridge formed by a low capacitance pinched-off HEMT transistor and tip-sample capacitance. We have achieved low noise level (0.13 e/VHz) and high spatial resolution (100 nm) for this technique, which promises to be a useful tool to study electronic behavior in nanoscale devices.

Bhandari, S.; Westervelt, R. M.

2014-12-01

318

2D Discrete Fourier Transform on Sliding Windows.  

PubMed

Discrete Fourier transform (DFT) is the most widely used method for determining the frequency spectra of digital signals. In this paper, a 2D sliding DFT (2D SDFT) algorithm is proposed for fast implementation of the DFT on 2D sliding windows. The proposed 2D SDFT algorithm directly computes the DFT bins of the current window using the precalculated bins of the previous window. Since the proposed algorithm is designed to accelerate the sliding transform process of a 2D input signal, it can be directly applied to computer vision and image processing applications. The theoretical analysis shows that the computational requirement of the proposed 2D SDFT algorithm is the lowest among existing 2D DFT algorithms. Moreover, the output of the 2D SDFT is mathematically equivalent to that of the traditional DFT at all pixel positions. PMID:25585421

Park, Chun-Su

2015-03-01

319

A comparative study of optical and radiative characteristics of X-ray-induced luminescent defects in Ag-doped glass and LiF thin films and their applications in 2-D imaging  

NASA Astrophysics Data System (ADS)

We report novel disk-type X-ray two-dimensional (2-D) imaging detectors utilising Ag-doped phosphate glass and lithium fluoride (LiF) thin films based on the radiophotoluminescence (RPL) and photoluminescence (PL) phenomena, respectively. The accumulated X-ray doses written in the form of atomic-scale Ag-related luminescent centres in Ag-doped glass and F-aggregated centres in LiF thin films were rapidly reconstructed as a dose distribution using a homemade readout system. The 2-D images reconstructed from the RPL and PL detectors are compared with that from the optically stimulated luminescence (OSL) detector. In addition, the optical and dosimetric characteristics of LiF thin films are investigated and evaluated. The possibilities of dose distributions with a high spatial resolution on the order of microns over large areas, a wide dynamic range covering 11 orders of magnitude and a non-destructive readout are successfully demonstrated by combining the Ag-doped glass with LiF thin films.

Kurobori, T.; Miyamoto, Y.; Maruyama, Y.; Yamamoto, T.; Sasaki, T.

2014-05-01

320

Lectures on 2D gravity and 2D string theory  

Microsoft Academic Search

This report discusses the following topics: loops and states in conformal field theory; brief review of the Liouville theory; 2D Euclidean quantum gravity 1 -- path integral approach; 2D Euclidean quantum gravity 2 -- canonical approach; states in 2D string theory; matrix model technology 1 -- method of orthogonal polynomials; matrix model technology 2 -- loops on the lattice; matrix

P. Ginsparg; Gregory Moore

1992-01-01

321

2D Prony-Huang transform: a new tool for 2D spectral analysis.  

PubMed

This paper provides an extension of the 1D Hilbert Huang transform for the analysis of images using recent optimization techniques. The proposed method consists of: 1) adaptively decomposing an image into oscillating parts called intrinsic mode functions (IMFs) using a mode decomposition procedure and 2) providing a local spectral analysis of the obtained IMFs in order to get the local amplitudes, frequencies, and orientations. For the decomposition step, we propose two robust 2D mode decompositions based on nonsmooth convex optimization: 1) a genuine 2D approach, which constrains the local extrema of the IMFs and 2) a pseudo-2D approach, which separately constrains the extrema of lines, columns, and diagonals. The spectral analysis step is an optimization strategy based on Prony annihilation property and applied on small square patches of the IMFs. The resulting 2D Prony–Huang transform is validated on simulated and real data. PMID:25330485

Schmitt, Jérémy; Pustelnik, Nelly; Borgnat, Pierre; Flandrin, Patrick; Condat, Laurent

2014-12-01

322

18 8 2007 8 2007-18-8-19 Performance Improvement for 2-D Scattering Center Extraction and  

E-print Network

Transform) . . . 2 ISAR 2-D MEMP 2-D ESPRIT . F-18 2 and F-18 aircraft to estimate 2-D scattering center and abtain 2-D ISAR image. Key words : Scattering 2-D MEMP, 2-D ESPRIT . 2 ISAR 2 , . 2 , F-18 2

Myung, Noh-Hoon

323

Multi-resolution level sets with shape priors: a validation report for 2D segmentation of prostate gland in T2W MR images.  

PubMed

The level set approach to segmentation of medical images has received considerable attention in recent years. Evolving an initial contour to converge to anatomical boundaries of an organ or tumor is a very appealing method, especially when it is based on a well-defined mathematical foundation. However, one drawback of such evolving method is its high computation time. It is desirable to design and implement algorithms that are not only accurate and robust but also fast in execution. Bresson et al. have proposed a variational model using both boundary and region information as well as shape priors. The latter can be a significant factor in medical image analysis. In this work, we combine the variational model of level set with a multi-resolution approach to accelerate the processing. The question is whether a multi-resolution context can make the segmentation faster without affecting the accuracy. As well, we investigate the question whether a premature convergence, which happens in a much shorter time, would reduce accuracy. We examine multiple semiautomated configurations to segment the prostate gland in T2W MR images. Comprehensive experimentation is conducted using a data set of a 100 patients (1,235 images) to verify the effectiveness of the multi-resolution level set with shape priors. The results show that the convergence speed can be increased by a factor of ??2.5 without affecting the segmentation accuracy. Furthermore, a premature convergence approach drastically increases the segmentation speed by a factor of ??17.9. PMID:24865859

Al-Qunaieer, Fares S; Tizhoosh, Hamid R; Rahnamayan, Shahryar

2014-12-01

324

Computer Vision for Fundamental Studies in Porous Media: Part I -- 2-D Image Acquisition and Processing for Microscopic Distribution of Oil, Water, and Pore Space Networks  

Microsoft Academic Search

Microscopic studies of the distributions of oil and water and of their networks in the pore space, at various relative saturations, are of fundamental importance in understanding migration, distribution, entrainment and mobilization of oil in the context of a particular (enhanced) oil recovery method. There has been an upsurge of interest in quantitative image analysis of pore morphology from two-dimensional

G. D. Yadav; I. F. Macdonald; I. Chatzis; F. A. L. Dullien

1986-01-01

325

Comparison of 3D and 2D breast density estimation from synthetic ultrasound tomography images and digital mammograms of anthropomorphic software breast phantoms  

NASA Astrophysics Data System (ADS)

Breast density descriptors were estimated from ultrasound tomography (UST) and digital mammogram (DM) images of 46 anthropomorphic software breast phantoms. Each phantom simulated a 450 ml or 700 ml breast with volumetric percent density (PD) values between 10% and 50%. The UST based volumetric breast density (VBD) estimates were calculated by thresholding the reconstructed UST images. Percent density (PD) values from DM images were estimated interactively by a clinical breast radiologist using Cumulus software. Such obtained UST VBD and Cumulus PD estimates were compared with the ground truth VBD values available from phantoms. The UST VBD values showed a high correlation with the ground truth, as evidenced by the Pearson correlation coefficient of r=0.93. The Cumulus PD values also showed a high correlation with the ground truth (r=0.84), as well as with the UST VBD values (r=0.78). The consistency in measuring the UST VBD and Cumulus PD values was analyzed using the standard error of the estimation by linear regression (?E). The ?E value for Cumulus PD was 1.5 times higher compared to the UST VBD (6.54 vs. 4.21). The ?E calculated from two repeated Cumulus estimation sessions (?E=4.66) was comparable with the UST. Potential sources of the observed errors in density measurement are the use of global thresholding and (for Cumulus) the human observer variability. This preliminary study of simulated phantom UST images showed promise for non-invasive estimation of breast density.

Bakic, Predrag R.; Li, Cuiping; West, Erik; Sak, Mark; Gavenonis, Sara C.; Duric, Nebojsa; Maidment, Andrew D. A.

2011-03-01

326

PCaAnalyser: A 2D-Image Analysis Based Module for Effective Determination of Prostate Cancer Progression in 3D Culture  

PubMed Central

Three-dimensional (3D) in vitro cell based assays for Prostate Cancer (PCa) research are rapidly becoming the preferred alternative to that of conventional 2D monolayer cultures. 3D assays more precisely mimic the microenvironment found in vivo, and thus are ideally suited to evaluate compounds and their suitability for progression in the drug discovery pipeline. To achieve the desired high throughput needed for most screening programs, automated quantification of 3D cultures is required. Towards this end, this paper reports on the development of a prototype analysis module for an automated high-content-analysis (HCA) system, which allows for accurate and fast investigation of in vitro 3D cell culture models for PCa. The Java based program, which we have named PCaAnalyser, uses novel algorithms that allow accurate and rapid quantitation of protein expression in 3D cell culture. As currently configured, the PCaAnalyser can quantify a range of biological parameters including: nuclei-count, nuclei-spheroid membership prediction, various function based classification of peripheral and non-peripheral areas to measure expression of biomarkers and protein constituents known to be associated with PCa progression, as well as defining segregate cellular-objects effectively for a range of signal-to-noise ratios. In addition, PCaAnalyser architecture is highly flexible, operating as a single independent analysis, as well as in batch mode; essential for High-Throughput-Screening (HTS). Utilising the PCaAnalyser, accurate and rapid analysis in an automated high throughput manner is provided, and reproducible analysis of the distribution and intensity of well-established markers associated with PCa progression in a range of metastatic PCa cell-lines (DU145 and PC3) in a 3D model demonstrated. PMID:24278197

Lovitt, Carrie J.; Avery, Vicky M.

2013-01-01

327

Design procedures for Strain Hardening Cement Composites (SHCC) and measurement of their shear properties by mechanical and 2-D Digital Image Correlation (DIC) method  

NASA Astrophysics Data System (ADS)

The main objective of this study is to investigate the behaviour and applications of strain hardening cement composites (SHCC). Application of SHCC for use in slabs of common configurations was studied and design procedures are prepared by employing yield line theory and integrating it with simplified tri-linear model developed in Arizona State University by Dr. Barzin Mobasher and Dr. Chote Soranakom. Intrinsic material property of moment-curvature response for SHCC was used to derive the relationship between applied load and deflection in a two-step process involving the limit state analysis and kinematically admissible displacements. For application of SHCC in structures such as shear walls, tensile and shear properties are necessary for design. Lot of research has already been done to study the tensile properties and therefore shear property study was undertaken to prepare a design guide. Shear response of textile reinforced concrete was investigated based on picture frame shear test method. The effects of orientation, volume of cement paste per layer, planar cross-section and volume fraction of textiles were investigated. Pultrusion was used for the production of textile reinforced concrete. It is an automated set-up with low equipment cost which provides uniform production and smooth final surface of the TRC. A 3-D optical non-contacting deformation measurement technique of digital image correlation (DIC) was used to conduct the image analysis on the shear samples by means of tracking the displacement field through comparison between the reference image and deformed images. DIC successfully obtained full-field strain distribution, displacement and strain versus time responses, demonstrated the bonding mechanism from perspective of strain field, and gave a relation between shear angle and shear strain.

Aswani, Karan

328

Infrared imaging of the surface temperature field of water during film spreading  

E-print Network

. These images were converted to surface temperature fields. The amount of turbulent structure present to being relevant to free surface turbulence, these results demonstrate the utility of infrared imagingInfrared imaging of the surface temperature field of water during film spreading J. R. Saylor and G

Saylor, John R.

329

Measurements and Modeling of Acetone Laser-Induced Fluorescence with Implications for Temperature-Imaging Diagnostics  

Microsoft Academic Search

Recent determinations of the temperature dependence of acetone fluorescence have permitted the ap- plication of acetone planar laser-induced fluorescence imaging, which was already popular for mapping concentration, to the measurement of temperature. With a view toward developing temperature- imaging diagnostics, we present atmospheric-pressure fluorescence and absorption results acquired with excitation at eight wavelengths across the absorption feature of acetone and

Mark C. Thurber; Brian J. Kirby; Martin Votsmeier; Ronald K. Hanson

1998-01-01

330

ECE Imaging of Temperature Fluctuations and Drift Waves in DIII-D Plasmas  

NASA Astrophysics Data System (ADS)

Recent observations of 2-D turbulent structures have been performed with the ECEI instrument on DIII-D. The experiments were performed in NBI and ECH-heated plasmas, over a range of external heating power. Correlation techniques similar to those used in Correlation Electron Cyclotron Emission (CECE) systems are employed, with the advantage that the ECEI system detects a full 2-D array of plasma locations: vertical separation is provided by an optical system and horizontal separation is provided by frequency discrimination in the detection electronics. Among the results are 2-D images of poloidally-propagating drift-waves, and correlation properties of fluctuations (<200 kHz) in both the radial and poloidal directions. Scaling and parameter dependencies on plasma and heating conditions will be presented. In addition to the physics results, the data demonstrates the viability of the ECEI system in the presence of ECH heating, which will also be discussed.

Zemedkun, Samuel; Munsat, Tobin; Tobias, Benjamin; Luhmann, Neville; Domier, Calvin

2012-10-01

331

Optimizing the Precision for Localizing Fluorescent Proteins in Living Cells by 2D Gaussian Fitting of Digital Images: Application to COPII-Coated Endoplasmic Reticulum Exit Sites  

PubMed Central

An insight into the operation of molecular motors has already been obtained under in vitro conditions from single-molecule tracking of proteins. It remains to analyze the effects of these motors on the position and secretion of specific organelles in the environment of the cell. For this purpose, we have investigated the accuracy of a standard algorithm to enable the tracking of particles in live-cell microscopy. The results have been applied to an example study into the role of the microtubule-motor kinesin on the function of COPII-coated secretory-cargo exit sites forming part of the mammalian endoplasmic reticulum. These exit sites are marked with multiple EYFP-tagged proteins to produce bright fluorescent particles, and a demonstration of the motility of vesicles, under different conditions in the cell, is described here. It is essential to use a low-level expression of fluorescent protein-tagged cellular components to ensure faithful replication for the behaviour of endogenous protein. However, this leads to a lower ratio for the signal-to-noise than is desired for the sub-pixel tracking of objects in digital images. This has driven the present effort to develop a computational model of the experiment in order to estimate the precision for localization of a fluorescent particle. Our work gives a greater insight, than has been managed in the past, into the accuracy and precision of particle tracking from live-cell imaging under a variety of different conditions, and it takes into consideration the current standards in digital technology for optical microscopy. PMID:18504570

Spence, Peter; Gupta, Vijay; Stephens, David J.; Hudson, Andrew J.

2008-01-01

332

Lennard-Jones 2D Metropolis Model  

NSDL National Science Digital Library

The Lennard-Jones 2D Metropolis Model is a Monte Carlo simulation of Lennard-Jones particles in two dimensions in contact with a heat bath. The default initial condition is a rectangular configuration of N=64 particles in a box of length L = 18 and a temperature T= 1. The Lennard-Jones 2D Metropolis Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5 modeling tool. It is distributed as a ready-to-run (compiled) Java archive.

Christian, Wolfgang

2014-07-27

333

Estimation of radiative properties and temperature distributions in coal-fired boiler furnaces by a portable image processing system  

SciTech Connect

This paper presented an experimental investigation on the estimation of radiative properties and temperature distributions in a 670 t/h coal-fired boiler furnace by a portable imaging processing system. The portable system has been calibrated by a blackbody furnace. Flame temperatures and emissivities were measured by the portable system and equivalent blackbody temperatures were deduced. Comparing the equivalent blackbody temperatures measured by the portable system and the infrared pyrometer, the relative difference is less than 4%. The reconstructed pseudo-instantaneous 2-D temperature distributions in two cross-sections can disclose the combustion status inside the furnace. The measured radiative properties of particles in the furnace proved there is significant scattering in coal-fired boiler furnaces and it can provide useful information for the calculation of radiative heat transfer and numerical simulation of combustion in coal-fired boiler furnaces. The preliminary experimental results show this technology will be helpful for the combustion diagnosis in coal-fired boiler furnaces. (author)

Li, Wenhao; Lou, Chun; Sun, Yipeng; Zhou, Huaichun [State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, 430074 Hubei (China)

2011-02-15

334

Update on 2-D array transducers for medical ultrasound  

Microsoft Academic Search

l½-D and 2-D arrays offer a myriad of new imaging modalities and benefits when compared to the linear array. However, with added benefits come many problems and challenges and l½-D and 2-D arrays are no exception. The authors give possible solutions to a number of these challenges. The increase in transducer channels needed in a 1½-D and 2-D array can

Stephen W. Smith; Richard E. Davidsen; Charles D. Emery; Richard L. Goldberg; Edward D. Light

1995-01-01

335

2-D Shape Representation and Recognition by Lattice Computing Techniques  

NASA Astrophysics Data System (ADS)

We consider binary images such that an image includes a single 2-D shape, from which we extract three populations of three different (shape) descriptors, respectively. Each population is represented by an Intervals' Number, or IN for short, in the mathematical lattice (F, ≼ ) of INs. In conclusion, a 2-D shape is represented in the Cartesian product lattice (F 3, ≼ ). We present a 2-D shape classification scheme based on fuzzy lattice reasoning (FLR). Preliminary experimental results have been encouraging. We discuss the potential of Lattice Computing (LC) techniques in image representation and recognition applications.

Kaburlasos, V. G.; Amanatiadis, A.; Papadakis, S. E.

336

Synchrotron X-ray 2D and 3D Elemental Imaging of CdSe/ZnS Quantum dot Nanoparticles in Daphnia Magna  

SciTech Connect

The potential toxicity of nanoparticles to aquatic organisms is of interest given that increased commercialization will inevitably lead to some instances of inadvertent environmental exposures. Cadmium selenide quantum dots (QDs) capped with zinc sulfide are used in the semiconductor industry and in cellular imaging. Their small size (<10 nm) suggests that they may be readily assimilated by exposed organisms. We exposed Daphnia magna to both red and green QDs and used synchrotron X-ray fluorescence to study the distribution of Zn and Se in the organism over a time period of 36 h. The QDs appeared to be confined to the gut, and there was no evidence of further assimilation into the organism. Zinc and Se fluorescence signals were highly correlated, suggesting that the QDs had not dissolved to any extent. There was no apparent difference between red or green QDs, i.e., there was no effect of QD size. 3D tomography confirmed that the QDs were exclusively in the gut area of the organism. It is possible that the QDs aggregated and were therefore too large to cross the gut wall.

Jackson, B.; Pace, H; Lanzirotti, A; Smith, R; Ranville, J

2009-01-01

337

Computation of three-phase capillary entry pressures and arc menisci configurations in pore geometries from 2D rock images: A combinatorial approach  

NASA Astrophysics Data System (ADS)

We present a semi-analytical, combinatorial approach to compute three-phase capillary entry pressures for gas invasion into pore throats with constant cross-sections of arbitrary shapes that are occupied by oil and/or water. For a specific set of three-phase capillary pressures, geometrically allowed gas/oil, oil/water and gas/water arc menisci are determined by moving two circles in opposite directions along the pore/solid boundary for each fluid pair such that the contact angle is defined at the front circular arcs. Intersections of the two circles determine the geometrically allowed arc menisci for each fluid pair. The resulting interfaces are combined systematically to allow for all geometrically possible three-phase configuration changes. The three-phase extension of the Mayer and Stowe - Princen method is adopted to calculate capillary entry pressures for all determined configuration candidates, from which the most favorable gas invasion configuration is determined. The model is validated by comparing computed three-phase capillary entry pressures and corresponding fluid configurations with analytical solutions in idealized triangular star-shaped pores. It is demonstrated that the model accounts for all scenarios that have been analyzed previously in these shapes. Finally, three-phase capillary entry pressures and associated fluid configurations are computed in throat cross-sections extracted from segmented SEM images of Bentheim sandstone. The computed gas/oil capillary entry pressures account for the expected dependence of oil/water capillary pressure in spreading and non-spreading fluid systems at the considered wetting conditions. Because these geometries are irregular and include constrictions, we introduce three-phase displacements that have not been identified previously in pore-network models that are based on idealized pore shapes. However, in the limited number of pore geometries considered in this work, we find that the favorable displacements are not generically different from those already encountered in network models previously, except that the size and shape of oil layers that are surrounded by gas and water are described more realistically. The significance of the results for describing oil connectivity in porous media accurately can only be evaluated by including throats with more complex cross-sections in three-phase pore-network models.

Zhou, Yingfang; Helland, Johan Olav; Hatzignatiou, Dimitrios G.

2014-07-01

338

Ultrasonic temperature imaging for guiding focused ultrasound surgery: effect of angle between imaging beam and therapy beam.  

PubMed

Ultrasonic temperature imaging is a promising technique for guiding focused ultrasound surgery (FUS). The FUS system is run at an initial, nonablative intensity and a diagnostic transducer images the heat-induced echo strain, which is proportional to the temperature rise. The echo strain image portrays an elliptical "hot spot" corresponding to the focal region of the therapy transducer. It is anticipated that such images will be used to predict the location of the thermal lesion that would be produced at an ablative intensity. We demonstrated in vitro that heat-induced echo strain images can visualize a spatial peak temperature rise of <2 degrees C (starting at room temperature). However, the imaging beam was perpendicular to the treatment beam in these experiments, whereas the most convenient approach in vivo would be to mount the imaging probe within the housing of the therapy transducer such that the two beams are coaxial. A previous simulation experiment predicted that echo strain images would be noisier for the coaxial configuration because sharp lateral gradients in axial displacement cause increased RF signal decorrelation within the beam width. The aim of the current study was to verify this prediction in vitro. We found, that for a temperature rise of approximately 4 degrees C, the mean contrast-to-noise ratio for coaxial and perpendicular echo strain images was 0.37 (+/-0.24) and 2.00 (+/-0.72) respectively. Furthermore, the decorrelation noise seen in the coaxial images obscured the posterior axial border of the hot spot. We conclude that the coaxial configuration will be useful for localizing the hot spot in the lateral direction. However, it may not be able to depict the axial extent of the hot spot or to portray a parameter that is directly related to temperature rise. PMID:15749564

Miller, Naomi R; Bograchev, Konstantin M; Bamber, Jeffrey C

2005-03-01

339

Implementation of 2D\\/3D Transformation for Clothing Panel  

Microsoft Academic Search

2D\\/3D transformation for clothing panel is one of most important steps for virtual clothing. And vector mesh generation is one of the basic tasks that complete 2D\\/3D transformation of clothing panel images and virtual clothing designs. Based on the classical methods of generating meshes, an algorithm for generating vector meshes which is suitable for garment panel images was presented. The

Xinrong Hu; Yan Bai; Shuqin Cui; Zhongmin Deng

2009-01-01

340

Enhanced detectability of small objects in correlated clutter using an improved 2-D adaptive lattice algorithm  

Microsoft Academic Search

Two-dimensional (2-D) adaptive filtering is a tech- nique that can be applied to many image processing applications. This paper will focus on the development of an improved 2- D adaptive lattice algorithm (2-D AL) and its application to the removal of correlated clutter to enhance the detectability of small objects in images. The two improvements proposed here are increased flexibility

Pearse A. Ffrench; James R. Zeidler; Walter H. Ku

1997-01-01

341

Determination of mean temperatures of normal whole breast and breast quadrants by infrared imaging and image analysis  

Microsoft Academic Search

In clinical testing it is standard to determine the normal ranged and then to determine if a test can differentiate normal from diseased patients. Now with the advent of uncooled staring array digital infrared imaging systems (Prism 2000; Bioyear Group, Houston, TX) and image analysis, numerical results (mean temperatures of the whole breast and quadrants of the breast) can be

J. F. Head; C. A. Lipari; R. L. Elliott

2001-01-01

342

The conceptual design of an electron cyclotron emission imaging system for studying ITER-like high temperature plasmas  

NASA Astrophysics Data System (ADS)

The design of an electron cyclotron emission imaging (ECEI) system for two-dimensional (2D) observation of the magnetohydrodynamical modes in high temperature ITER (from ‘International Thermonuclear Experimental Reactor’) H-mode-like plasmas (5.3 T and 25 keV) based on fundamental ordinary mode (O1-mode) and second-harmonic extraordinary mode (X2-mode) measurements is explored conceptually. For studying the spatial resolution in high temperature plasmas, the relativistic broadening and inward shift of the emission layer in the mid-plane are calculated. The radial spatial resolution is significantly degraded in the range R < 5.1 m for the O1-mode and in the range R < 6.9 m for the X2-mode. The region with R < 6.5 m is inaccessible for X2-mode study. The emission layer width is enlarged in a narrow region of the pedestal due to the magnetic field being modified by the large pressure gradient. The broadening and shift in the poloidal plane are also calculated, to investigate their effects on 2D measurements. The frequency range of electron cyclotron emission measurements is selected to protect the system from stray radiations of the 170 GHz electron cyclotron resonance heating source and to avoid harmonic overlap. The frequency ranges of 115–160 GHz for the O1-mode and 230–320 GHz for the X2-mode provide radial coverage of 5.9 < R < 8.2 m or ?0.15 < r/a < 1.The ECEI system utilizes a dual-array detection technique which provides a simultaneous measurement at two radial positions, and each array has 8 by 16 (radial by vertical) channels. The radial image size with 8 channels is ?41–76 cm for the O1-mode and ?19–36 cm for the X2-mode, with sufficient resolution. The front-end optics, which focuses the electron cyclotron emission to the low loss corrugated transmission waveguides, is designed with two flat mirrors and two focusing mini-lens arrays. The vertical image size with 16 channels is ?150 cm and the spot size of each channel is 8–15 cm in the plasma region, taking into account the sensitivity pattern of the waveguide. The refraction effect due to inhomogeneous plasma enlarges the vertical image size up to 20% and 5% for the O1-mode and X2-mode cases, respectively. The horizontal distortion due to the relativistic inwards shift is reduced by the increased toroidal field in the core region.

Lee, W.; Yun, G. S.; Park, H. K.; Nam, Y. B.; Seon, C. R.

2014-09-01

343

Gas-phase toluene LIF temperature imaging near surfaces at 10 kHz  

Microsoft Academic Search

Information on transient temperature distributions is important for the study of heat transfer and reacting flows, including\\u000a combustion. Laser diagnostic methods have been developed for temperature imaging purposes but so far have largely been constrained\\u000a to low temporal resolution measurements. Diode-pumped solid-state lasers and high frame rate CMOS cameras have enabled the\\u000a development of a gas-phase temperature imaging method based

Michael Cundy; Philipp Trunk; Andreas Dreizler; Volker Sick

344

Random Walk 2D Model  

NSDL National Science Digital Library

The EJS Random Walk 2D Model simulates a 2-D random walk. You can change the number of walkers and probability of going a given direction. You can modify this simulation if you have Ejs installed by right-clicking within the plot and selecting âOpen Ejs Modelâ from the pop-up menu item. The Random Walk 2D Model was created using the Easy Java Simulations (Ejs) modeling tool. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the ejs_stp_RandomWalk2D.jar file will run the program if Java is installed. Ejs is a part of the Open Source Physics Project and is designed to make it easier to access, modify, and generate computer models. Additional Ejs models are available. They can be found by searching ComPADRE for Open Source Physics, OSP, or Ejs.

Christian, Wolfgang

2009-04-27

345

Estimating an image sensor's temperature for darksignal-correction  

NASA Astrophysics Data System (ADS)

An approach for darksignal-correction is presented that uses a model of each pixel's darksignal, which depends on the sensor's settings (integration time and gain) and its temperature. It is shown how one can improve the outcome of such a darksignal-correction strategy by using the darksignal of some pixels in order to compute an estimate of the sensor's temperature. Experimental results indicate that the darksignals' dependency on temperature and gain is more complex than considered in up-to-date darksignal models. In this paper it is shown how one can cope with this complex behaviour when estimating the temperature out of the darksignal. Experimental results indicate, that our method yields better results than using temperature measurements of dedicated temperature sensors.

Achatzi, Julian; Fischer, Gregor; Zimmer, Volker; Paulus, Dietrich

2014-03-01

346

Three-dimensional temperature imaging around a gold microwire  

NASA Astrophysics Data System (ADS)

We report on the temperature mapping around a resistively heated gold microwire. The temperature is determined by measuring the thermal-induced distortion of an incident optical wavefront crossing the system. The optical technique we introduce herein allows, in addition to 3-dimensional temperature measurements, a retrieval of the heat source density at optical resolution. Experimental results are supported by finite element simulations and electric measurements. Applications are envisioned in microelectronics, microfluidics, or nanochemistry.

Bon, Pierre; Belaid, Nadia; Lagrange, Denis; Bergaud, Christian; Rigneault, Hervé; Monneret, Serge; Baffou, Guillaume

2013-06-01

347

MAGNUM-2D computer code: user's guide  

SciTech Connect

Information relevant to the general use of the MAGNUM-2D computer code is presented. This computer code was developed for the purpose of modeling (i.e., simulating) the thermal and hydraulic conditions in the vicinity of a waste package emplaced in a deep geologic repository. The MAGNUM-2D computer computes (1) the temperature field surrounding the waste package as a function of the heat generation rate of the nuclear waste and thermal properties of the basalt and (2) the hydraulic head distribution and associated groundwater flow fields as a function of the temperature gradients and hydraulic properties of the basalt. MAGNUM-2D is a two-dimensional numerical model for transient or steady-state analysis of coupled heat transfer and groundwater flow in a fractured porous medium. The governing equations consist of a set of coupled, quasi-linear partial differential equations that are solved using a Galerkin finite-element technique. A Newton-Raphson algorithm is embedded in the Galerkin functional to formulate the problem in terms of the incremental changes in the dependent variables. Both triangular and quadrilateral finite elements are used to represent the continuum portions of the spatial domain. Line elements may be used to represent discrete conduits. 18 refs., 4 figs., 1 tab.

England, R.L.; Kline, N.W.; Ekblad, K.J.; Baca, R.G.

1985-01-01

348

MAGNETIC RESONANCE IMAGING OF TEMPERATURE STRESSED COTTON ROOTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil temperature is a major factor impacting the growth and function of plant root systems. Changes in root development in response to changes in soil temperature are difficult to assess on a dynamic basis since destructive sampling and disturbance of roots is necessary for any evaluation. This stud...

349

2D unitary ESPRIT for efficient 2D parameter estimation  

Microsoft Academic Search

Considers multiple narrowband signals that are incident upon a planar sensor array. 2D unitary ESPRIT is a new closed-form high resolution algorithm to provide automatically paired source azimuth and elevation angle estimates along with an efficient way to reconstruct the impinging signals. In the final stage of the algorithm, the real and imaginary parts of the ith eigenvalue of a

Martin Haardt; Michael D. Zoltowski; C. P. Mathews; J. A. Nossek

1995-01-01

350

QM Probability 2D Program  

NSDL National Science Digital Library

The QM Probability 2D program displays the time evolution of the two-dimensional probability density using color to represent its magnitude. The default wave function is a two-state superposition in the x (nx = 1,2) and y dimension (ny = 3,4) state in an infinite square well. Additional states and other potential energy functions can be specified using the Display | Switch GUI menu item. QM Probability 2D is one of 18 Open Source Physics programs that model time-dependent quantum mechanics using an energy eigenstate expansion. It is distributed as a ready-to-run (compiled) Java archive. Double clicking the qm_probability_2d.jar file will run the program if Java is installed. Other programs provide additional visualizations. They can be found by searching ComPADRE for Open Source Physics, OSP, or Superposition.

Christian, Wolfgang

2008-05-20

351

Contour and pattern recognition of temperature fields with image analysis  

NASA Astrophysics Data System (ADS)

BMW Rolls-Royce is developing the civil turbofan engine family BR700 with a thrust range from 12.000 to 23.000 pounds. To improve the efficiency, life time and cycles of an engine it is necessary to know the wall temperature on its components. The distribution of turbine wall temperature is measured with so-called Thermal Paints, which change their color irreversibly according to the local maximum temperature. A CCD color line scan camera system to record and analyze these data is being developed. To understand the thermal distribution across the surface of a component, the paint color change boundary is identified and transformed into calibrated temperature data. This thermal distribution can be used to validate the engineering thermal model.

Gier, Stefan; Scheuerpflug, Wolfgang

1998-03-01

352

GRAPHICS PROGRAMMING Section B Java 2D  

E-print Network

GRAPHICS PROGRAMMING Section B ­ Java 2D 20 - Graphics2D: Introduction 21 - Graphics2D: Shapes 22 2D: General Path Curves 29 - Graphics 2D: Constructive Area Geometry Gary Hill December 2003 Java 2 Java initially through the Abstract Window Toolkit, which was extended to include swing, shortly

Hill, Gary

353

2D Gaussian distributions. Equal height.  

E-print Network

2D Gaussian distributions. Equal height. Noise-free. Well separated. #12;2D Gaussian distributions. Equal height. Noise-free. Well separated. #12;2D Gaussian distributions. Equal height. Noise-free. Somewhat separated. #12;2D Gaussian distributions. Equal height. Noise-free. Overlapping. #12;2D Gaussian

Oakes, Terry

354

2D 3D * iklee)@yonsei.ac.kr  

E-print Network

, Vol. 99, No. 4, pp. 590~606 (2011) [7] R. Fabbri, L. D. F. Costa, J. C. Torelli, and O. M. Bruno, 2D] L. Zhang and W. J. Tam, Stereoscopic Image Generation Based on Depth Images for 3D TV, IEEE, Stereoscopic 3D Copy & Paste, ACM Transactions on Graphics, 29(6), p. 147 (2010) [5] V. D. Silva, A. Fernando

Lee, In-Kwon

355

Automatic 2D-to-3D Video Conversion Techniques for 3DTV  

E-print Network

2D video to 3D: Depth Map Estimation Depth Image Based Rendering (DIBR) Demo Conclusions #12 Video Input 3D Video Output Estimated Depth Map Left View Right View #12;What is Depth Map or Depth the furthest value and the grey level 255 specifying the closest value. 2D Image Depth Image (Map) #12;Depth

Po, Lai-Man

356

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction  

NASA Astrophysics Data System (ADS)

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min-1 on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively.

Huber, S.; Mooslechner, M.; Mitterlechner, B.; Weichenberger, H.; Serpa, M.; Sedlmayer, F.; Deutschmann, H.

2013-09-01

357

Image quality improvements of electronic portal imaging devices by multi-level gain calibration and temperature correction.  

PubMed

Amorphous silicon (aSi:H) flat panel detectors are prevalent in radiotherapy for megavoltage imaging tasks. Any clinical and dosimetrical application requires a well-defined dose response of the system to achieve meaningful results. Due to radiation damages, panels deteriorate and the linearity of pixel response to dose as well as the stability with regard to changing operating temperatures get worse with time. Using a single level gain correction can lead to an error of about 23% when irradiating a flood field image with 100 MU min(-1) on an old detector. A multi-level gain (MLG) correction is introduced, emending the nonlinearities and subpanel-related artifacts caused by insufficient radiation hardness of amplifiers in the read-out electronics. With rising temperature, offset values typically increase (up to 300 gray values) while the response at higher dose values per frame remain constant for a majority of pixels. To account for temperature-related image artifacts, two additional temperature correction methods have been developed. MLG in combination with temperature corrections can re-establish the aSi:H image quality to the performance required by reliable medical verification tools. Furthermore, the life span and recalibration intervals of these costly devices can be prolonged decisively. PMID:23999060

Huber, S; Mooslechner, M; Mitterlechner, B; Weichenberger, H; Serpa, M; Sedlmayer, F; Deutschmann, H

2013-09-21

358

Tree visualization with Tree-maps: A 2-d space-filling approach  

Microsoft Academic Search

this paper deals with a two-dimensional (2-d) space-fillingapproach in which each node is a rectangle whose area is proportional to some attribute suchas node size.Research on relationships between 2-d images and their representation in tree structures hasfocussed on node and link representations of 2-d images. This work includes quad-trees(Samet, 1989) and their variants which are important in image processing. The

Ben Shneiderman

1991-01-01

359

The 2D ?-Dirac oscillator  

NASA Astrophysics Data System (ADS)

In this Letter, 2D Dirac oscillator in the quantum deformed framework generated by the ?-Poincaré-Hopf algebra is considered. The problem is formulated using the ?-deformed Dirac equation. The resulting theory reveals that the energies and wave functions of the oscillator are modified by the deformation parameter.

Andrade, Fabiano M.; Silva, Edilberto O.

2014-11-01

360

Intracellular temperature mapping with a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy  

PubMed Central

Cellular functions are fundamentally regulated by intracellular temperature, which influences biochemical reactions inside a cell. Despite the important contributions to biological and medical applications that it would offer, intracellular temperature mapping has not been achieved. Here we demonstrate the first intracellular temperature mapping based on a fluorescent polymeric thermometer and fluorescence lifetime imaging microscopy. The spatial and temperature resolutions of our thermometry were at the diffraction limited level (200 nm) and 0.18–0.58 °C. The intracellular temperature distribution we observed indicated that the nucleus and centrosome of a COS7 cell, both showed a significantly higher temperature than the cytoplasm and that the temperature gap between the nucleus and the cytoplasm differed depending on the cell cycle. The heat production from mitochondria was also observed as a proximal local temperature increase. These results showed that our new intracellular thermometry could determine an intrinsic relationship between the temperature and organelle function. PMID:22426226

Okabe, Kohki; Inada, Noriko; Gota, Chie; Harada, Yoshie; Funatsu, Takashi; Uchiyama, Seiichi

2012-01-01

361

Temperature dependent operation of PSAPD-based compact gamma camera for SPECT imaging  

PubMed Central

We investigated the dependence of image quality on the temperature of a position sensitive avalanche photodiode (PSAPD)-based small animal single photon emission computed tomography (SPECT) gamma camera with a CsI:Tl scintillator. Currently, nitrogen gas cooling is preferred to operate PSAPDs in order to minimize the dark current shot noise. Being able to operate a PSAPD at a relatively high temperature (e.g., 5 °C) would allow a more compact and simple cooling system for the PSAPD. In our investigation, the temperature of the PSAPD was controlled by varying the flow of cold nitrogen gas through the PSAPD module and varied from ?40 °C to 20 °C. Three experiments were performed to demonstrate the performance variation over this temperature range. The point spread function (PSF) of the gamma camera was measured at various temperatures, showing variation of full-width-half-maximum (FWHM) of the PSF. In addition, a 99mTc-pertechnetate (140 keV) flood source was imaged and the visibility of the scintillator segmentation (16×16 array, 8 mm × 8 mm area, 400 ?m pixel size) at different temperatures was evaluated. Comparison of image quality was made at ?25 °C and 5 °C using a mouse heart phantom filled with an aqueous solution of 99mTc-pertechnetate and imaged using a 0.5 mm pinhole collimator made of tungsten. The reconstructed image quality of the mouse heart phantom at 5 °C degraded in comparision to the reconstructed image quality at ?25 °C. However, the defect and structure of the mouse heart phantom were clearly observed, showing the feasibility of operating PSAPDs for SPECT imaging at 5 °C, a temperature that would not need the nitrogen cooling. All PSAPD evaluations were conducted with an applied bias voltage that allowed the highest gain at a given temperature. PMID:24465051

Kim, Sangtaek; McClish, Mickel; Alhassen, Fares; Seo, Youngho; Shah, Kanai S.; Gould, Robert G.

2011-01-01

362

Earth Observatory Data and Images - Sea Surface Temperature  

NSDL National Science Digital Library

Visitors can use sea surface temperature data to build animations that show seasonal and yearly fluctuations, and compare them to data from other selected months and years. The animations can be constructed in map or globe formats and may be viewed on the website or downloaded.

363

Motion Compensation for Temperature Imaging using the Change in Ultrasonic Backscattered Energy  

E-print Network

Motion Compensation for Temperature Imaging using the Change in Ultrasonic Backscattered Energy and in-vitro experiments [2] verified that the change in backscattered ultrasonic energy (CBE) is monotonic (approximately 0.2~0.3dB/oC) with temperature in the hyperthermia range, motivating the usage

Arthur, R. Martin

364

Imaging of local temperature distributions in mesas of high-Tc superconducting terahertz sources  

NASA Astrophysics Data System (ADS)

Stacks of intrinsic Josephson junctions in high-Tc superconductors are a promising source of intense, continuous, and monochromatic terahertz waves. In this paer, we establish a fluorescence-based temperature imaging system to directly image the surface temperature on a Bi2Sr2CaCu2O8+? mesa sample. Intense terahertz emissions are observed in both high- and low-bias regimes, where the mesa voltage satisfies the cavity resonance condition. In the high- bias regime, the temperature distributions are shown to be inhomogeneous with a considerable temperature rise. In contrast, in the low-bias regime, the distributions are rather uniform and the local temperature is close to the bath temperature over the entire sample.

Tsujimoto, M.; Kambara, H.; Maeda, Y.; Yoshioka, Y.; Nakagawa, Y.; Kakeya, I.

2014-12-01

365

Noise temperature improvement for magnetic fusion plasma millimeter wave imaging systems  

SciTech Connect

Significant progress has been made in the imaging and visualization of magnetohydrodynamic and microturbulence phenomena in magnetic fusion plasmas [B. Tobias et al., Plasma Fusion Res. 6, 2106042 (2011)]. Of particular importance have been microwave electron cyclotron emission imaging and microwave imaging reflectometry systems for imaging T{sub e} and n{sub e} fluctuations. These instruments have employed heterodyne receiver arrays with Schottky diode mixer elements directly connected to individual antennas. Consequently, the noise temperature has been strongly determined by the conversion loss with typical noise temperatures of ?60?000 K. However, this can be significantly improved by making use of recent advances in Monolithic Microwave Integrated Circuit chip low noise amplifiers to insert a pre-amplifier in front of the Schottky diode mixer element. In a proof-of-principle design at V-Band (50–75 GHz), significant improvement of noise temperature from the current 60?000 K to measured 4000 K has been obtained.

Lai, J.; Domier, C. W.; Luhmann, N. C. [Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616 (United States)] [Department of Electrical and Computer Engineering, University of California at Davis, Davis, California 95616 (United States)

2014-03-15

366

Temperature and Emissivity Measurements with the Multispectral Thermal Imager Satellite at Ivanpah Playa  

SciTech Connect

The Multispectral Thermal Imager (MTI) is a research and development satellite sponsored by the Department of Energy (DOE) for accurate water surface temperature retrieval. MTI uses five thermal spectral bands to retrieve ground temperatures. The application of MTI for land-based temperature and emissivity retrieval has been limited. Savannah River Technology Center conducted several ground truth campaigns at Ivanpah Playa to measure reflectance, temperature and emissivity. The results of MTI temperature and emissivity retrievals and material identification will be discussed in context with the ground truth data.

Villa-Aleman, E.

2003-01-06

367

Two-Dimensional Thin Layer Chromatography (2D-TLC) 1. Resuspend RNA pellet in 5 l ddH2O. Place at room temperature for 5-15 minutes. Use pipette tip  

E-print Network

119 Two-Dimensional Thin Layer Chromatography (2D-TLC) 1. Resuspend RNA pellet in 5 µl ddH2O. Place: AMP, A9272; CMP, C1133; GMP, G3628; UMP, U1126. 4. Mark origin on chromatography plate using a pencil, no indicator (from VWR). 5. Spot sample on chromatography plate at origin. Do 0.1 - 0.2 µl at a time. Dry

Aris, John P.

368

Thermal Imaging in the Chemistry Laboratory Thermal imaging devices take advantage of the fact that all objects with a temperature above absolute  

E-print Network

Thermal Imaging in the Chemistry Laboratory Thermal imaging devices take advantage of the fact in temperature. This process uses the fact that the amount of radiation emitted by an object is proportional

Short, Daniel

369

Design of temperature measurement system based on two-color imaging in adaptive optics of CCD  

NASA Astrophysics Data System (ADS)

Optical temperature measurement technique has been widely researched in current temperature detection field. Because the three-color thermometry based on color CCD has many disadvantages affecting temperature measurement precision, such as the non-ideal spectral responsive bandwidth of RGB three-channel, the emissivity variance and the nonlinear output channel, as well as the few visible light share of all the radiant energy. So a new design of temperature measurement system based on two-color imaging in adaptive optics of CCD has been proposed in this paper. This system was designed according to the principle of self-adaption imaging based on the feedback error signal. Especially, the optical passive athermalisation was applied to eliminate the impact of temperature change on system image quality, and the substrate-mask was also placed in optical path to resolve the problem of external stray light interference. Furthermore, a new temperature measurement algorithm of two-color radiation imaging based on grayscale inversion was deduced, which can avoid the influence of gray body assumption and non-ideal spectral response bandwidth, and correct the interference of CCD hardware noise as well. Another fast registration algorithm of two-color image based on wavelet transformation and mutual variance was also introduced, which has a high translation and rotation registration precision. Eventually, the field experiment has been carried out based on this temperature measurement system. And the result has shown that this system can calculate and display the temperature distribution of boiler flame, and have the characteristics of high accuracy, good real-time and strong practicality.

Wu, Yong-hua; Hu, Yi-hua; Jiang, Fei; Zhang, Lin-hu

2010-10-01

370

Using optoacoustic imaging for measuring the temperature dependence of Grüneisen parameter in optically absorbing solutions  

PubMed Central

Grüneisen parameter is a key temperature-dependent physical characteristic responsible for thermoelastic efficiency of materials. We propose a new methodology for accurate measurements of temperature dependence of Grüneisen parameter in optically absorbing solutions. We use two-dimensional optoacoustic (OA) imaging to improve accuracy of measurements. Our approach eliminates contribution of local optical fluence and absorbance. To validate the proposed methodology, we studied temperature dependence of aqueous cupric sulfate solutions in the range from 22 to 4°C. Our results for the most diluted salt perfectly matched known temperature dependence for the Grüneisen parameter of water. We also found that Grüneisen-temperature relationship for cupric sulfate exhibits linear trend with respect to the concentration. In addition to accurate measurements of Grüneisen changes with temperature, the developed technique provides a basis for future high precision OA temperature monitoring in live tissues. PMID:24150350

Petrova, Elena; Ermilov, Sergey; Su, Richard; Nadvoretskiy, Vyacheslav; Conjusteau, André; Oraevsky, Alexander

2013-01-01

371

Spectroscopic diagnostics of temperatures for a non-axisymmetric coupling arc by monochromatic imaging  

NASA Astrophysics Data System (ADS)

The twin-electrode TIG coupling arc is a newly developed non-axisymmetric welding arc. The imaging method that consists of a high-speed camera with a narrow-band filter has been used to obtain monochromatic images of a coupling arc at atmospheric pressure. The spatial emission coefficients of the non-axisymmetric coupling arc are reconstructed by means of the Maldonado method. Under the assumption of local thermodynamic equilibrium, the temperature distribution of the coupling arc has been determined. The temperature distribution is similar to an ellipse, and the short axis of the ellipse is in the direction that the two electrodes are arranged along. The highest temperature area is in the middle of both electrodes. It indicates that there is a strong interaction within the coupling arc. The results show that the imaging method is an efficient way of characterizing the non-axisymmetric coupling arc.

Zhang, Guangjun; Xiong, Jun; Hu, Yutang

2010-10-01

372

Development of a two-color laser-induced fluorescence based temperature imaging device with micro-scale resolution  

E-print Network

dyes was used to obtain a two-dimensional temperature map of the fluid. The final system is capable of generating images with 5 micron resolution and has a sensitivity to temperature of about 0.8% per degree Kelvin. The temperature field images were...

Gallina, Mark J.

2012-06-07

373

Two-wavelength Raman imaging for non-intrusive monitoring of transient temperature in microfluidic devices  

NASA Astrophysics Data System (ADS)

The present study proposes a non-intrusive visualization technique based on two-wavelength Raman imaging for in-situ monitoring of the unsteady temperature field in microfluidic systems. The measurement principle relies on the contrasting temperature dependencies of hydrogen-bonded and non-hydrogen-bonded OH stretching modes of the water Raman band, whose intensities were simultaneously captured by two cameras equipped with corresponding bandpass filters. The temperature distributions were then determined from the intensity ratio of the simultaneously-obtained Raman images, which enables compensation for temporal fluctuation and spatial inhomogeneity of the excitation laser intensity. A calibration experiment exhibited a linear relationship between the temperature and the intensity ratio in the range 293-343?K and least-regression analysis gave an uncertainty of 1.43?K at 95% confidence level. By applying the calibration data, time series temperature distributions were quantitatively visualized in a Y-shaped milli-channel at a spatial resolution of 6.0? × ?6.0?µm2 with an acquisition time of 16.5?s. The measurement result clearly exhibited the temporal evolution of the temperature field and was compared with the values obtained by thermocouples. This paper therefore demonstrates the viability of employing the two-wavelength Raman imaging technique for temperature measurements in microfluidic devices.

Kuriyama, Reiko; Sato, Yohei

2014-09-01

374

Jamming of 2D foams  

NASA Astrophysics Data System (ADS)

We probe the jamming of 2D wet foams by lateral compression of a bidisperse foam monolayer sandwiched between a glass plate and a fluid surface. Boundaries and residual gravitational effects prevent the foam to be truly unjammed, obstructing the observation of a jammed/unjammed transition. Instead, we find a clear transition from a ``gravity jammed'' to a ``boundary jammed'' state, where the bulk modulus jumps from essentially zero to a finite value, in agreement with theory. In addition, we probe the nonaffine bubble motion, which becomes large near this transition.

Siemens, Alexander; van Hecke, Martin

2013-03-01

375

IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS Visualization Task Performance with 2D, 3D,  

E-print Network

.3 Picture/Image Generation - Display Algorithms, J. Computer Applications (e.g., CAD, Medical Imaging medical scans. To see details without occlu- sion, radiologists typically view such data in 2D slices

Tory, Melanie

376

Preliminary Analysis of Images from the Thermospheric Temperature Image on Fast, Affordable, Science and Technology Satellite (FASTSAT)  

NASA Technical Reports Server (NTRS)

The Thermospheric Temperature Imager (TTI) on Fast, Affordable, Science and Technology SATellite (FASTSAT) measures the upper atmospheric atomic oxygen emission at 135.6 nm and the molecular nitrogen LBH emission at 135.4 nm to determine the atmospheric O/N2 density ratio. Observations of variations in this thermospheric ratio correspond to electron density variations in the ionosphere. The TTI design makes use of a Fabry-Perot interferometer to measure Doppler widened atmospheric emissions to determine neutral atmospheric temperature from low Earth orbit. FASTSAT launched November 10, 2010 and TTI is currently observing geomagnetic signatures in the aurora and airglow. This work is supported by NASA.

Rodriquez, Marcello; Jones, Sarah; Mentzell, Eric; Gill, Nathaniel

2011-01-01

377

Preliminary Analysis of Images from the Thermospheric Temperature Imager on Fast, Affordable, Science and Technology SATellite (FASTSAT)  

NASA Astrophysics Data System (ADS)

The Thermospheric Temperature Imager (TTI) on Fast, Affordable, Science and Technology SATellite (FASTSAT) measures the upper atmospheric atomic oxygen emission at 135.6 nm and the molecular nitrogen LBH emission at 135.4 nm to determine the atmospheric O/N2 density ratio. Observations of variations in this thermosheric ratio correspond to electron density variations in the ionosphere. The TTI design makes use of a Fabry-Perot interferometer to measure Doppler widened atmospheric emissions to determine neutral atmospheric temperature from low Earth orbit. FASTSAT launched November 10, 2010 and TTI is currently observing geomagnetic signatures in the aurora and airglow. This work is supported by NASA.

Rodriguez, M.; Jones, S.; Mentzell, E.; Gill, N.

2011-12-01

378

Relationships between brain and body temperature, clinical and imaging outcomes after ischemic stroke  

PubMed Central

Pyrexia soon after stroke is associated with severe stroke and poor functional outcome. Few studies have assessed brain temperature after stroke in patients, so little is known of its associations with body temperature, stroke severity, or outcome. We measured temperatures in ischemic and normal-appearing brain using 1H-magnetic resonance spectroscopy and its correlations with body (tympanic) temperature measured four-hourly, infarct growth by 5 days, early neurologic (National Institute of Health Stroke Scale, NIHSS) and late functional outcome (death or dependency). Among 40 patients (mean age 73 years, median NIHSS 7, imaged at median 17?hours), temperature in ischemic brain was higher than in normal-appearing brain on admission (38.6°C-core, 37.9°C-contralateral hemisphere, P=0.03) but both were equally elevated by 5 days; both were higher than tympanic temperature. Ischemic lesion temperature was not associated with NIHSS or 3-month functional outcome; in contrast, higher contralateral normal-appearing brain temperature was associated with worse NIHSS, infarct expansion and poor functional outcome, similar to associations for tympanic temperature. We conclude that brain temperature is higher than body temperature; that elevated temperature in ischemic brain reflects a local tissue response to ischemia, whereas pyrexia reflects the systemic response to stroke, occurs later, and is associated with adverse outcomes. PMID:23571281

Karaszewski, Bartosz; Carpenter, Trevor K; Thomas, Ralph G R; Armitage, Paul A; Lymer, Georgina Katherine S; Marshall, Ian; Dennis, Martin S; Wardlaw, Joanna M

2013-01-01

379

Application of CCD images and colorimetry temperature measure for combustion monitoring and control  

NASA Astrophysics Data System (ADS)

In power stations, a CCD set is used to observe furnace flame images directly to distinguish the current combustion status of a boiler. Actually, more combustion information can be gained from flame images: the temperature distribution can be reconstructed inversely, and the furnace radiation can be described quantificationally. Colorimetry temperature measure and greyscale normalization is included in this technology. Moreover, many important run-states such as flameout and flame center excursion can be caught by automation systems using the pattern recognition. Methods of combustion characteristic pattern recognition are discussed. And some applications for improving combustion control system are described.

Huang, Yongli; Qu, Tan; Zhou, HuaiChun; Yuan, Ping; Han, Shudong

2000-05-01

380

A 2D autoregressive method for deformation evaluation in registration of remote sensing data  

Microsoft Academic Search

A registration method is developed based on an A* algorithm in conjunction with a 2D autoregressive model used for image representation. The A* algorithm serves for obtaining the initial pixels which used further for determining the innovation process. Prior to this step the 2D autoregressive parameters are calculated using an initial set of pixels from the original image. The error

Ko Bong Fung; D. Ionescu

1993-01-01

381

Multi-scale and multi-spectral shape analysis: from 2d to 3d  

Microsoft Academic Search

Shape analysis is a fundamental aspect of many problems in computer graphics and computer vision, including shape matching, shape registration, object recognition and classification. Since the SIFT achieves excellent matching results in 2D image domain, it inspires us to convert the 3D shape analysis to 2D image analysis using geometric maps. However, the major disadvantage of geometric maps is that

Zhaoqiang Lai

2011-01-01

382

Thermoreflectance temperature imaging of integrated circuits: calibration technique and quantitative comparison with integrated sensors and simulations  

Microsoft Academic Search

Camera-based thermoreflectance microscopy is a unique tool for high spatial resolution thermal imaging of working integrated circuits. However, a calibration is necessary to obtain quantitative temperatures on the complex surface of integrated circuits. The spatial and temperature resolutions reached by thermoreflectance are excellent (360 nm and 2.5 × 10-2 K in 1 min here), but the precision is more difficult

G. Tessier; M.-L. Polignano; S. Pavageau; C. Filloy; D. Fournier; F. Cerutti; I. Mica

2006-01-01

383

Qualitative gas temperature distribution in positive DC glow corona using spectral image processing in atmospheric air  

NASA Astrophysics Data System (ADS)

An experimental method of determining a qualitative two-dimensional image of the gas temperature in stationary atmospheric nonthermal plasma by spectral image processing was presented. In the experiment, a steady-state glow corona discharge was generated by applying a positive DC voltage to a rod-plane electrode in synthetic air. The changes in the gas temperature distribution due to the amplitude of applied voltage and the ambient gas pressure were investigated. Spectral images of a positive DC glow corona were taken using a gated ICCD camera with ultranarrow band-pass filters, corresponding to the head and tail of a N2 second positive system band (0–2). The qualitative gas temperature was obtained from the emission intensity ratio between the head and tail of the N2 second positive system band (0–2). From the results, we confirmed that the gas temperature and its distribution of a positive DC glow corona increased with increasing applied voltage. In particular, just before the sparkover voltage, a distinctly high temperature region was formed in the positive DC glow at the tip of the rod electrode. In addition, the gas temperature decreased and its distribution spread diffusely with decreasing ambient gas pressure.

Matsumoto, Takao; Inada, Yoichi; Shimizu, Daisuke; Izawa, Yasuji; Nishijima, Kiyoto

2015-01-01

384

In situ X-ray ptychography imaging of high-temperature CO{sub 2} acceptor particle agglomerates  

SciTech Connect

Imaging nanoparticles under relevant reaction conditions of high temperature and gas pressure is difficult because conventional imaging techniques, like transmission electron microscopy, cannot be used. Here we demonstrate that the coherent diffractive imaging technique of X-ray ptychography can be used for in situ phase contrast imaging in structure studies at atmospheric pressure and elevated temperatures. Lithium zirconate, a candidate CO{sub 2} capture material, was studied at a pressure of one atmosphere in air and in CO{sub 2}, at temperatures exceeding 600?°C. Images with a spatial resolution better than 200?nm were retrieved, and possibilities for improving the experiment are described.

Høydalsvik, Kristin; Bø Fløystad, Jostein; Esmaeili, Morteza; Mathiesen, Ragnvald H.; Breiby, Dag W., E-mail: dag.breiby@ntnu.no [Department of Physics, Norwegian University of Science and Technology (NTNU), Høgskoleringen 5, 7491 Trondheim (Norway); Zhao, Tiejun; Rønning, Magnus [Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), Sem Sælands vei 4, 7491 Trondheim (Norway); Diaz, Ana [Paul Scherrer Institut, 5232 Villigen (Switzerland); Andreasen, Jens W. [Department of Energy Conversion and Storage, Technical University of Denmark, Frederiksborgvej 399, 4000 Roskilde (Denmark)

2014-06-16

385

Lennard-Jones 2D Demon Model  

NSDL National Science Digital Library

The Lennard-Jones 2D Demon Model is a Monte Carlo simulation of Lennard-Jones particles in two dimensions interacting with a Monte Carlo demon. A Monte Carlo demon is an extra degree of freedom that is allowed to transfer energy as it attempts to change the state of the system. The demon keeps track of its own energy and can take or give energy to a particle as it interacts with a randomly chosen particle. Because the demon cannot have negative energy, the total energy of the system remains constant -- as it should in the microcanonical ensemble. The demon is, in effect, a thermometer. Its extra degree of freedom perturbs the system very little and the average demon energy is proportional to the temperature of the system. (See Statistical and Thermal Physics notes by H. Gould and J. Tobochnik.) The Lennard-Jones 2D Demon Model was developed using the Easy Java/JavaScript Simulations (EjsS) version 5 modeling tool. It is distributed as a ready-to-run (compiled) Java archive.

Christian, Wolfgang

2014-08-01

386

Face Recognition Using 2D and 3D Facial Data  

Microsoft Academic Search

Results are presented for the largest experimental study to date that investigates the comparison and combination of 2D and 3D face recognition. To our knowledge, this is also the only such study to incorporate signicant time lapse be- tween gallery and probe image acquisition, and to look at the effect of depth resolution. Recognition results are ob- tained in (1)

Kyong I. Chang; Kevin W. Bowyer; Patrick J. Flynn

2003-01-01

387

Evaluation of a vat wall-mounted image capture system using image processing techniques to monitor curd moisture during syneresis with temperature treatments  

Microsoft Academic Search

The objective of this study was to evaluate a vat wall-mounted image capture system with a range of image processing techniques (threshold, first order and second order grey level statistics and fractal dimension) to monitor curd moisture content during syneresis with a range of temperature treatments. Milk was renneted using three temperature treatments (32°C throughout, a cooking step from 32

María José Mateo; Donal J. O’Callaghan; Aoife A. Gowen; Colm P. O’Donnell

2010-01-01

388

Foveated active tracking with redundant 2D motion parameters  

Microsoft Academic Search

This work presents a real-time active vision tracking system based on log-polar image motion estimation with 2D geometric deformation models. We present a very efficient parametric motion estimation method, where most computation can be done offline. We propose a redundant parameterization for the geometric deformations, which improve the convergence range of the algorithm. A foveated image representation provides extra computational

Alexandre Bernardino; José Santos-victor; Giulio Sandini

2002-01-01

389

From 2D towards 3D cartography of hollow organs  

Microsoft Academic Search

Endoscopy is a standard imaging modality commonly used in different medical fields like lesion diagnosis in hollow organs or mini-invasive surgery. Meanwhile, endoscopic data suffer from the fact that each image of a video-sequence only corresponds to a small 2D field of view. This paper presents a mosaicing algorithm leading to visually coherent large field of view maps. The ability

Christian Daul; Walter Blondel; Achraf Ben-Hamadou; Rosebet Miranda-Luna; Charles Soussen; Didier Wolf; François Guillemin

2010-01-01

390

Real-time microwave imaging of differential temperature for thermal therapy monitoring.  

PubMed

A microwave imaging system for real-time 3-D imaging of differential temperature has been developed for the monitoring and feedback of thermal therapy systems. Design parameters are constrained by features of a prototype-focused microwave thermal therapy system for the breast, operating at 915 MHz. Real-time imaging is accomplished with a precomputed linear inverse scattering solution combined with continuous vector network analyzer (VNA) measurements of a 36-antenna, HFSS-modeled, cylindrical cavity. Volumetric images of differential change of dielectric constant due to temperature are formed with a refresh rate as fast as 1 frame/s and 1 (°)C resolution. Procedures for data segmentation and postprocessed S-parameter error-correction are developed. Antenna pair VNA calibration is accelerated by using the cavity as the unknown thru standard. The device is tested on water targets and a simple breast phantom. Differentially heated targets are successfully imaged in cluttered environments. The rate of change of scattering contrast magnitude correlates 1:1 with target temperature. PMID:24845289

Haynes, Mark; Stang, John; Moghaddam, Mahta

2014-06-01

391

Real-time Microwave Imaging of Differential Temperature for Thermal Therapy Monitoring  

PubMed Central

A microwave imaging system for real-time 3D imaging of differential temperature has been developed for the monitoring and feedback of thermal therapy systems. Design parameters are constrained by features of a prototype focused microwave thermal therapy system for the breast, operating at 915 MHz. Real-time imaging is accomplished with a precomputed linear inverse scattering solution combined with continuous Vector Network Analyzer (VNA) measurements of a 36-antenna, HFSS modeled, cylindrical cavity. Volumetric images of differential change of dielectric constant due to temperature are formed with a refresh rate as fast as 1 frame per second and 1°C resolution. Procedures for data segmentation and post-processed S-parameter error-correction are developed. Antenna pair VNA calibration is accelerated by using the cavity as the unknown thru standard. The device is tested on water targets and a simple breast phantom. Differentially heated targets are successfully imaged in cluttered environments. The rate of change of scattering contrast magnitude correlates 1:1 with target temperature. PMID:24845289

Haynes, Mark; Stang, John; Moghaddam, Mahta

2014-01-01

392

Toluene laser-induced fluorescence for in-cylinder temperature imaging in internal combustion engines  

Microsoft Academic Search

A single-laser single-camera imaging technique was demonstrated for in-cylinder temperature distribution measurements in a\\u000a direct-injection internal combustion engine. The single excitation wavelength two-color detection technique is based on toluene\\u000a laser-induced fluorescence (LIF). Toluene-LIF emission spectra show a red-shift with increasing temperature. Temperature can\\u000a thus be determined from the ratio of the signal measured in two separate wavelength ranges independent of

M. Luong; R. Zhang; C. Schulz; V. Sick

2008-01-01

393

A potential nuclear magnetic resonance imaging approach for noncontact temperature measurement  

NASA Astrophysics Data System (ADS)

It is proposed that in a nuclear magnetic resonance (NMR) imaging experiment that it should be possible to measure temperature through an extended volume. The basis for such a measurement would depend upon sensing a temperature dependent on NMR parameter in an inert, volatile molecule (or fluid) filling the volume of interest. Exploratory work suggest that one suitable candidate for such a purpose might be CH3Cl. Possible parameters, other inert gases and feasible measurement schemes that might provide such temperature measurement are discussed.

Manatt, Stanley L.

1989-06-01

394

A potential nuclear magnetic resonance imaging approach for noncontact temperature measurement  

NASA Technical Reports Server (NTRS)

It is proposed that in a nuclear magnetic resonance (NMR) imaging experiment that it should be possible to measure temperature through an extended volume. The basis for such a measurement would depend upon sensing a temperature dependent on NMR parameter in an inert, volatile molecule (or fluid) filling the volume of interest. Exploratory work suggest that one suitable candidate for such a purpose might be CH3Cl. Possible parameters, other inert gases and feasible measurement schemes that might provide such temperature measurement are discussed.

Manatt, Stanley L.

1989-01-01

395

2D quasiperiodic plasmonic crystals  

PubMed Central

Nanophotonic structures with irregular symmetry, such as quasiperiodic plasmonic crystals, have gained an increasing amount of attention, in particular as potential candidates to enhance the absorption of solar cells in an angular insensitive fashion. To examine the photonic bandstructure of such systems that determines their optical properties, it is necessary to measure and model normal and oblique light interaction with plasmonic crystals. We determine the different propagation vectors and consider the interaction of all possible waveguide modes and particle plasmons in a 2D metallic photonic quasicrystal, in conjunction with the dispersion relations of a slab waveguide. Using a Fano model, we calculate the optical properties for normal and inclined light incidence. Comparing measurements of a quasiperiodic lattice to the modelled spectra for angle of incidence variation in both azimuthal and polar direction of the sample gives excellent agreement and confirms the predictive power of our model. PMID:23209871

Bauer, Christina; Kobiela, Georg; Giessen, Harald

2012-01-01

396

Temperature resolution enhancing of commercially available THz passive cameras due to computer processing of images  

NASA Astrophysics Data System (ADS)

As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. Efficiency of using the passive THz camera depends on its temperature resolution. This characteristic specifies possibilities of the detection of concealed object: minimal size of the object, maximal distance of the detection, image detail. One of probable ways for a quality image enhancing consists in computer processing of image. Using computer processing of the THz image of objects concealed on the human body, one may improve it many times. Consequently, the instrumental resolution of such device may be increased without any additional engineering efforts. We demonstrate new possibilities for seeing the clothes details, which raw images, produced by the THz cameras, do not allow to see. We achieve good quality of the image due to applying various spatial filters with the aim to demonstrate independence of processed images on math operations. This result demonstrates a feasibility of objects seeing. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp., and Capital Normal University (Beijing, China).

Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

2014-06-01

397

Ultrafast 2D IR Vibrational Echo Spectroscopy  

E-print Network

Ultrafast 2D IR Vibrational Echo Spectroscopy JUNRONG ZHENG, KYUNGWON KWAK, AND M. D. FAYER The experimental technique and applications of ultrafast two- dimensional infrared (2D IR) vibrational echo spectrum of a mixture of species. I. Introduction Ultrafast 2D IR vibrational echo spectroscopy1

Fayer, Michael D.

398

Retrieval and validation of mesospheric temperatures from Wind Imaging Interferometer observations  

NASA Astrophysics Data System (ADS)

A method has been developed for the retrieval of mesospheric temperatures in the 65-90 km altitude range from satellite observations made by the Wind Imaging Interferometer (WINDII) aboard the Upper Atmosphere Research Satellite (UARS). Retrieved temperatures are derived from Rayleigh scattered sunlight observed in a wavelength band centered at 553 nm. Integrated line-of-sight radiance observations are inverted to tangent height volume scattering profiles, which are proportional to atmospheric density. From these, absolute temperature profiles are calculated using a technique derived from established Rayleigh lidar retrieval methods assuming that the atmosphere is in hydrostatic equilibrium and that it obeys the ideal gas law. Sources of error have been identified and typical temperature uncertainty values for individual profiles are determined to be <2.5%, 5.5%, and 13% for altitudes of 70 km, 80 km, and 90 km, respectively. A thorough comparison of the derived WINDII temperatures is performed against a number of ground-based and satellite measurements, including ground-based lidar, falling spheres, the High Resolution Doppler Imager observations aboard UARS, and against common atmospheric models. The data consist of spring equinox observations in March and April 1992/1993, summer solstice data in July/August 1992/1993, fall equinox data in September/October 1992, and winter solstice data in December 1992/1993 and January 1993/1994. The results of the comparisons show that WINDII temperatures are in reasonable to excellent agreement with a number of established temperature studies. In particular, July Northern Hemisphere monthly averaged temperatures show that characteristics of the mesopause obtained by WINDII are in very good agreement with other measurements. This good agreement with other established data sets and a determination of the error bounds of our recovered temperatures have shown that WINDII data can be used to confidently derive near-global temperatures of the upper mesosphere between 65 and 90 km. Above 90 km the errors increase, and systematic differences may arise with other measurements.

Shepherd, Marianna G.; Reid, Boedijanti; Zhang, Shengpan; Solheim, Brian H.; Shepherd, Gordon G.; Wickwar, Vincent B.; Herron, Joshua P.

2001-11-01

399

BOREAS Level-2 MAS Surface Reflectance and Temperature Images in BSQ Format  

NASA Technical Reports Server (NTRS)

The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science Aircraft Data Acquisition Program focused on providing the research teams with the remotely sensed aircraft data products they needed to compare and spatially extend point results. The MODIS Airborne Simulator (MAS) images, along with other remotely sensed data, were collected to provide spatially extensive information over the primary study areas. This information includes biophysical parameter maps such as surface reflectance and temperature. Collection of the MAS images occurred over the study areas during the 1994 field campaigns. The level-2 MAS data cover the dates of 21-Jul-1994, 24-Jul-1994, 04-Aug-1994, and 08-Aug-1994. The data are not geographically/geometrically corrected; however, files of relative X and Y coordinates for each image pixel were derived by using the C130 navigation data in a MAS scan model. The data are provided in binary image format files.

Hall, Forrest G. (Editor); Newcomer, Jeffrey (Editor); Lobitz, Brad; Spanner, Michael; Strub, Richard; Lobitz, Brad

2000-01-01

400

2-D chromatography applied to the study of block copolymers synthesized by nitroxide-mediated controlled free-radical seeded emulsion polymerization.  

PubMed

2-D chromatography with gradient polymer elution chromatography in the first dimension was used to characterize a series of block copolymers prepared by nitroxide-mediated controlled free-radical seeded emulsion polymerization. The data provide a detailed picture of the different populations generated during the successive stages of the reaction. In particular, deviations from ideal conditions, such as an exothermic temperature spike, are obvious from the 2-D chromatogram, and its interpretation provides unique insight into the reaction mechanisms. Finally, atomic force microscopy images obtained on films cast from copolymer solutions evidence the relationship between polymer microstructure and film morphology. PMID:20972974

Moyses, Stephan; Ness, Jason; Papakonstantopoulos, George

2010-11-01

401

2D/3D facial feature extraction  

NASA Astrophysics Data System (ADS)

We propose and compare three different automatic landmarking methods for near-frontal faces. The face information is provided as 480x640 gray-level images in addition to the corresponding 3D scene depth information. All three methods follow a coarse-to-fine suite and use the 3D information in an assist role. The first method employs a combination of principal component analysis (PCA) and independent component analysis (ICA) features to analyze the Gabor feature set. The second method uses a subset of DCT coefficients for template-based matching. These two methods employ SVM classifiers with polynomial kernel functions. The third method uses a mixture of factor analyzers to learn Gabor filter outputs. We contrast the localization performance separately with 2D texture and 3D depth information. Although the 3D depth information per se does not perform as well as texture images in landmark localization, the 3D information has still a beneficial role in eliminating the background and the false alarms.

Çinar Akakin, Hatice; Ali Salah, Albert; Akarun, Lale; Sankur, Bülent

2006-02-01

402

Exact computation of scalar 2D aerial imagery  

NASA Astrophysics Data System (ADS)

An exact formulation of the problem of imaging a 2D object through a Koehler illumination system is presented; the accurate simulation of a real layout is then not time- limited but memory-limited. The main idea behind the algorithm is that the boundary of the region that comprise a typical TCC Is made up of circular arcs, and therefore the area - which determines the value of the TCC - should be exactly computable in terms of elementary analytical functions. A change to integration around the boundary leads to an expression with minimal dependence on expensive functions such as arctangents and square roots. Numerical comparisons are made for a simple 2D structure.

Gordon, Ronald L.

2002-07-01

403

2-D wavelet packet spectrum for texture analysis.  

PubMed

This brief derives a 2-D spectrum estimator from some recent results on the statistical properties of wavelet packet coefficients of random processes. It provides an analysis of the bias of this estimator with respect to the wavelet order. This brief also discusses the performance of this wavelet-based estimator, in comparison with the conventional 2-D Fourier-based spectrum estimator on texture analysis and content-based image retrieval. It highlights the effectiveness of the wavelet-based spectrum estimation. PMID:23412622

Atto, Abdourrahmane M; Berthoumieu, Yannick; Bolon, Philippe

2013-06-01

404

Implementation of 2-D DCT based on FPGA  

NASA Astrophysics Data System (ADS)

Discrete Cosine Transform (DCT) plays an important role in the image and video compression, and it has been widely used in JPEG, MPEG, H.26x. DCT being implemented by hardware is crucial to improve the speed of image compression. This paper presents a method that 2-D DCT is implemented by FPGA, which is based on the algorithm of row-column decomposition, and the parallel structure is used to achieve high throughput. The design is achieved by top-down design methodology and described with Verilog HDL in RTL level. The hardware of 2-D DCT is implemented by the FPGA EP2C35F672C8 made by ALTERA. The experiment results show that the delay time is as low as 15 ns, and the clock frequency as high as 138.35 MHz, which can satisfy the requirements of the real-time video image compression.

Guo, Bao-Zeng; Niu, Li; Liu, Zhi-Ming

2010-08-01

405

Ultrasound elastographic imaging of thermal lesions and temperature profiles during radiofrequency ablation  

NASA Astrophysics Data System (ADS)

Manual palpation to sense variations in tissue stiffness for disease diagnosis has been regularly performed by clinicians for centuries. However, it is generally limited to large and superficial structures and the ability of the physician performing the palpation. Imaging of tissue stiffness or elastic properties via the aid of modern imaging such as ultrasound and magnetic resonance imaging, referred to as elastography, enhances the capability for disease diagnosis. In addition, elastography could be used for monitoring tissue response to minimally invasive ablative therapies, which are performed percutaneously to destruct tumors with minimum damage to surrounding tissue. Monitoring tissue temperature during ablation is another approach to estimate tissue damage. The ultimate goal of this dissertation is to improve the image quality of elastograms and temperature profiles for visualizing thermal lesions during and after ablative therapies. Elastographic imaging of thermal lesions is evaluated by comparison of sizes, shapes, and volumes with the results obtained using gross pathology. Semiautomated segmentation of lesion boundaries on elastograms is also developed. It provides comparable results to those with manual segmentation. Elastograms imaged during radiofrequency ablation in vitro show that the impact of gas bubbles during ablation on the ability to delineate the thermal lesion is small. Two novel methods to reduce noise artifacts in elastograms, and an accurate estimation of displacement vectors are proposed. The first method applies wavelet-denoising algorithms to the displacement estimates. The second method utilizes angular compounding of the elastograms generated using ultrasound signal frames acquired from different insonification angles. These angular frames are also utilized to estimate all tissue displacement vector components in response to a deformation. These enable the generation of normal and shear strain elastograms and Poisson's ratio elastograms, which provide additional valuable information for disease diagnosis. Finally, measurements of temperature dependent variables, including sound speed, attenuation coefficient, and thermal expansion in canine liver tissue, are performed. This information is necessary for the estimation of the temperature profile during ablation. A mapping function between the gradient of timeshifts and tissue temperature is calculated using this information and subsequently applied to estimate temperature profiles.

Techavipoo, Udomchai

406

USING HINODE/EXTREME-ULTRAVIOLET IMAGING SPECTROMETER TO CONFIRM A SEISMOLOGICALLY INFERRED CORONAL TEMPERATURE  

SciTech Connect

The Extreme-Ultraviolet Imaging Spectrometer on board the HINODE satellite is used to examine the loop system described in Marsh et al. by applying spectroscopic diagnostic methods. A simple isothermal mapping algorithm is applied to determine where the assumption of isothermal plasma may be valid, and the emission measure locii technique is used to determine the temperature profile along the base of the loop system. It is found that, along the base, the loop has a uniform temperature profile with a mean temperature of 0.89 +- 0.09 MK which is in agreement with the temperature determined seismologically in Marsh et al., using observations interpreted as the slow magnetoacoustic mode. The results further strengthen the slow mode interpretation, propagation at a uniform sound speed, and the analysis method applied in Marsh et al. It is found that it is not possible to discriminate between the slow mode phase speed and the sound speed within the precision of the present observations.

Marsh, M. S.; Walsh, R. W., E-mail: mike.s.marsh@gmail.co [Jeremiah Horrocks Institute for Astrophysics and Supercomputing, University of Central Lancashire, Preston, PR1 2HE (United Kingdom)

2009-11-20