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Sample records for angular resolution imaging

  1. High angular resolution diffusion imaging with stimulated echoes

    DEFF Research Database (Denmark)

    Lundell, Henrik; Alexander, Daniel C; Dyrby, Tim B

    2014-01-01

    other than the diffusion gradients in the STEAM sequence contribute much greater diffusion weighting than in PGSE and lead to a disrupted experimental design. Here, we introduce a simple compensation to the STEAM acquisition that avoids the orientational bias and disrupted experiment design...... angular resolution diffusion imaging (HARDI) data were acquired with and without the proposed compensation. The data were processed to derive standard diffusion tensor imaging (DTI) maps, which highlight the need for the compensation. Ignoring the other gradient pulses, a bias in DTI parameters from STEAM...

  2. How does angular resolution affect diffusion imaging measures?

    Science.gov (United States)

    Zhan, Liang; Leow, Alex D; Jahanshad, Neda; Chiang, Ming-Chang; Barysheva, Marina; Lee, Agatha D; Toga, Arthur W; McMahon, Katie L; de Zubicaray, Greig I; Wright, Margaret J; Thompson, Paul M

    2010-01-15

    A key question in diffusion imaging is how many diffusion-weighted images suffice to provide adequate signal-to-noise ratio (SNR) for studies of fiber integrity. Motion, physiological effects, and scan duration all affect the achievable SNR in real brain images, making theoretical studies and simulations only partially useful. We therefore scanned 50 healthy adults with 105-gradient high-angular resolution diffusion imaging (HARDI) at 4T. From gradient image subsets of varying size (6spherical angular distribution energy, we created SNR plots (versus gradient numbers) for seven common diffusion anisotropy indices: fractional and relative anisotropy (FA, RA), mean diffusivity (MD), volume ratio (VR), geodesic anisotropy (GA), its hyperbolic tangent (tGA), and generalized fractional anisotropy (GFA). SNR, defined in a region of interest in the corpus callosum, was near-maximal with 58, 66, and 62 gradients for MD, FA, and RA, respectively, and with about 55 gradients for GA and tGA. For VR and GFA, SNR increased rapidly with more gradients. SNR was optimized when the ratio of diffusion-sensitized to non-sensitized images was 9.13 for GA and tGA, 10.57 for FA, 9.17 for RA, and 26 for MD and VR. In orientation density functions modeling the HARDI signal as a continuous mixture of tensors, the diffusion profile reconstruction accuracy rose rapidly with additional gradients. These plots may help in making trade-off decisions when designing diffusion imaging protocols. PMID:19819339

  3. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging.

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions.

  4. Converting Multi-Shell and Diffusion Spectrum Imaging to High Angular Resolution Diffusion Imaging

    Science.gov (United States)

    Yeh, Fang-Cheng; Verstynen, Timothy D.

    2016-01-01

    Multi-shell and diffusion spectrum imaging (DSI) are becoming increasingly popular methods of acquiring diffusion MRI data in a research context. However, single-shell acquisitions, such as diffusion tensor imaging (DTI) and high angular resolution diffusion imaging (HARDI), still remain the most common acquisition schemes in practice. Here we tested whether multi-shell and DSI data have conversion flexibility to be interpolated into corresponding HARDI data. We acquired multi-shell and DSI data on both a phantom and in vivo human tissue and converted them to HARDI. The correlation and difference between their diffusion signals, anisotropy values, diffusivity measurements, fiber orientations, connectivity matrices, and network measures were examined. Our analysis result showed that the diffusion signals, anisotropy, diffusivity, and connectivity matrix of the HARDI converted from multi-shell and DSI were highly correlated with those of the HARDI acquired on the MR scanner, with correlation coefficients around 0.8~0.9. The average angular error between converted and original HARDI was 20.7° at voxels with signal-to-noise ratios greater than 5. The network topology measures had less than 2% difference, whereas the average nodal measures had a percentage difference around 4~7%. In general, multi-shell and DSI acquisitions can be converted to their corresponding single-shell HARDI with high fidelity. This supports multi-shell and DSI acquisitions over HARDI acquisition as the scheme of choice for diffusion acquisitions. PMID:27683539

  5. Development of a high angular resolution diffusion imaging human brain template.

    Science.gov (United States)

    Varentsova, Anna; Zhang, Shengwei; Arfanakis, Konstantinos

    2014-05-01

    Brain diffusion templates contain rich information about the microstructure of the brain, and are used as references in spatial normalization or in the development of brain atlases. The accuracy of diffusion templates constructed based on the diffusion tensor (DT) model is limited in regions with complex neuronal micro-architecture. High angular resolution diffusion imaging (HARDI) overcomes limitations of the DT model and is capable of resolving intravoxel heterogeneity. However, when HARDI is combined with multiple-shot sequences to minimize image artifacts, the scan time becomes inappropriate for human brain imaging. In this work, an artifact-free HARDI template of the human brain was developed from low angular resolution multiple-shot diffusion data. The resulting HARDI template was produced in ICBM-152 space based on Turboprop diffusion data, was shown to resolve complex neuronal micro-architecture in regions with intravoxel heterogeneity, and contained fiber orientation information consistent with known human brain anatomy.

  6. Contrast and resolution analysis of angular domain imaging for iterative optical projection tomography reconstruction

    Science.gov (United States)

    Ng, Eldon; Vasefi, Fartash; Kaminska, Bozena; Chapman, Glenn H.; Carson, Jeffrey J. L.

    2010-02-01

    Angular domain imaging (ADI) generates a projection image of an attenuating target within a turbid medium by employing a silicon micro-tunnel array to reject photons that have deviated from the initial propagation direction. In this imaging method, image contrast and resolution are position dependent. The objective of this work was to first characterize the contrast and resolution of the ADI system at a multitude of locations within the imaging plane. The second objective was to compare the reconstructions of different targets using filtered back projection and iterative reconstruction algorithms. The ADI system consisted of a diode laser laser (808nm, CW, ThorLabs) with a beam expander for illumination of the sample cuvette. At the opposite side of the cuvette, an Angular Filter Array (AFA) of 80 μm x 80 μm square-shaped tunnels 1 cm in length was used to reject the transmitted scattered light. Image-forming light exiting the AFA was detected by a linear CCD (16-bit, Mightex). Our approach was to translate two point attenuators (0.5 mm graphite rod, 0.368 mm drill bit) submerged in a 0.6% IntralipidTM dilution using a SCARA robot (Epson E2S351S) to cover a 37x37 and 45x45 matrix of grid points in the imaging plane within the 1 cm path length sample cuvette. At each grid point, a one-dimensional point-spread distribution was collected and system contrast and resolution were measured. Then, the robot was used to rotate the target to collect projection images at several projection angles of various objects, and reconstructed with a filtered back projection and an iterative reconstruction algorithm.

  7. Non-Parametric Tests of Structure for High Angular Resolution Diffusion Imaging in Q-Space

    CERN Document Server

    Olhede, Sofia C

    2010-01-01

    High angular resolution diffusion imaging data is the observed characteristic function for the local diffusion of water molecules in tissue. This data is used to infer structural information in brain imaging. Non-parametric scalar measures are proposed to summarize such data, and to locally characterize spatial features of the diffusion probability density function (PDF), relying on the geometry of the characteristic function. Summary statistics are defined so that their distributions are, to first order, both independent of nuisance parameters and also analytically tractable. The dominant direction of the diffusion at a spatial location (voxel) is determined, and a new set of axes are introduced in Fourier space. Variation quantified in these axes determines the local spatial properties of the diffusion density. Non-parametric hypothesis tests for determining whether the diffusion is unimodal, isotropic or multi-modal are proposed. More subtle characteristics of white-matter microstructure, such as the degre...

  8. Generalized diffusion tensor imaging and analytical relationships between diffusion tensor imaging and high angular resolution diffusion imaging.

    Science.gov (United States)

    Ozarslan, Evren; Mareci, Thomas H

    2003-11-01

    A new method for mapping diffusivity profiles in tissue is presented. The Bloch-Torrey equation is modified to include a diffusion term with an arbitrary rank Cartesian tensor. This equation is solved to give the expression for the generalized Stejskal-Tanner formula quantifying diffusive attenuation in complicated geometries. This makes it possible to calculate the components of higher-rank tensors without using the computationally-difficult spherical harmonic transform. General theoretical relations between the diffusion tensor (DT) components measured by traditional (rank-2) DT imaging (DTI) and 3D distribution of diffusivities, as measured by high angular resolution diffusion imaging (HARDI) methods, are derived. Also, the spherical tensor components from HARDI are related to the rank-2 DT. The relationships between higher- and lower-rank Cartesian DTs are also presented. The inadequacy of the traditional rank-2 tensor model is demonstrated with simulations, and the method is applied to excised rat brain data collected in a spin-echo HARDI experiment. PMID:14587006

  9. Holographic imaging of crowded fields: high angular resolution imaging with excellent quality at very low cost

    Science.gov (United States)

    Schödel, R.; Yelda, S.; Ghez, A.; Girard, J. H.; Labadie, L.; Rebolo, R.; Pérez-Garrido, A.; Morris, M. R.

    2013-02-01

    We present a method for speckle holography that is optimized for crowded fields. Its two key features are an iterative improvement of the instantaneous point spread functions (PSFs) extracted from each speckle frame and the (optional) simultaneous use of multiple reference stars. In this way, high signal-to-noise ratio and accuracy can be achieved on the PSF for each short exposure, which results in sensitive, high-Strehl reconstructed images. We have tested our method with different instruments, on a range of targets, and from the N[10 μm] to the I[0.9 μm] band. In terms of PSF cosmetics, stability and Strehl ratio, holographic imaging can be equal, and even superior, to the capabilities of currently available adaptive optics (AO) systems, particularly at short near-infrared to optical wavelengths. It outperforms lucky imaging because it makes use of the entire PSF and reduces the need for frame selection, thus, leading to higher Strehl and improved sensitivity. Image reconstruction a posteriori, the possibility to use multiple reference stars and the fact that these reference stars can be rather faint means that holographic imaging offers a simple way to image large, dense stellar fields near the diffraction limit of large telescopes, similar to, but much less technologically demanding than, the capabilities of a multiconjugate AO system. The method can be used with a large range of already existing imaging instruments and can also be combined with AO imaging when the corrected PSF is unstable.

  10. High Angular Resolution Stellar Imaging with Occultations from the Cassini Spacecraft II: Kronocyclic Tomography

    CERN Document Server

    Stewart, Paul N; Nicholson, Philip D; Hedman, Matthew M; Lloyd, James P

    2015-01-01

    We present an advance in the use of Cassini observations of stellar occultations by the rings of Saturn for stellar studies. Stewart et al. (2013) demonstrated the potential use of such observations for measuring stellar angular diameters. Here, we use these same observations, and tomographic imaging reconstruction techniques, to produce two dimensional images of complex stellar systems. We detail the determination of the basic observational reference frame. A technique for recovering model-independent brightness profiles for data from each occulting edge is discussed, along with the tomographic combination of these profiles to build an image of the source star. Finally we demonstrate the technique with recovered images of the {\\alpha} Centauri binary system and the circumstellar environment of the evolved late-type giant star, Mira.

  11. Angular-resolution and material-characterization measurements for a dual-particle imaging system with mixed-oxide fuel

    Science.gov (United States)

    Poitrasson-Rivière, Alexis; Polack, J. Kyle; Hamel, Michael C.; Klemm, Dietrich D.; Ito, Kai; McSpaden, Alexander T.; Flaska, Marek; Clarke, Shaun D.; Pozzi, Sara A.; Tomanin, Alice; Peerani, Paolo

    2015-10-01

    A dual-particle imaging (DPI) system, capable of simultaneously imaging fast neutrons and gamma rays, has been operated in the presence of mixed-oxide (MOX) fuel to assess the system's angular resolution and material-characterization capabilities. The detection principle is based on the scattering physics of neutrons (elastic scattering) and gamma rays (Compton scattering) in organic and inorganic scintillators. The detection system is designed as a combination of a two-plane Compton camera and a neutron-scatter camera. The front plane consists of EJ-309 liquid scintillators and the back plane consists of interleaved EJ-309 and NaI(Tl) scintillators. MCNPX-PoliMi was used to optimize the geometry of the system and the resulting prototype was built and tested using a Cf-252 source as an SNM surrogate. A software package was developed to acquire and process data in real time. The software was used for a measurement campaign to assess the angular resolution of the imaging system with MOX samples. Measurements of two MOX canisters of similar isotopics and intensity were performed for 6 different canister separations (from 5° to 30°, corresponding to distances of 21 cm and 131 cm, respectively). The measurements yielded a minimum separation of 20° at 2.5 m (86-cm separation) required to see 2 separate hot spots. Additionally, the results displayed good agreement with MCNPX-PoliMi simulations. These results indicate an angular resolution between 15° and 20°, given the 5° step. Coupled with its large field of view, and its capability to differentiate between spontaneous fission and (α,n) sources, the DPI system shows its potential for nuclear-nonproliferation applications.

  12. New diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models.

    Science.gov (United States)

    Poupon, Cyril; Rieul, Bernard; Kezele, Irina; Perrin, Muriel; Poupon, Fabrice; Mangin, Jean-François

    2008-12-01

    We present new diffusion phantoms dedicated to the study and validation of high-angular-resolution diffusion imaging (HARDI) models. The phantom design permits the application of imaging parameters that are typically employed in studies of the human brain. The phantoms were made of small-diameter acrylic fibers, chosen for their high hydrophobicity and flexibility that ensured good control of the phantom geometry. The polyurethane medium was filled under vacuum with an aqueous solution that was previously degassed, doped with gadolinium-tetraazacyclododecanetetraacetic acid (Gd-DOTA), and treated by ultrasonic waves. Two versions of such phantoms were manufactured and tested. The phantom's applicability was demonstrated on an analytical Q-ball model. Numerical simulations were performed to assess the accuracy of the phantom. The phantom data will be made accessible to the community with the objective of analyzing various HARDI models. PMID:19030160

  13. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    Energy Technology Data Exchange (ETDEWEB)

    Caiazzo, Giuseppina; Trojsi, Francesca; Cirillo, Mario; Tedeschi, Gioacchino [MRI Research Center SUN-FISM-Neurological Institute for Diagnosis and Care ' ' Hermitage Capodimonte' ' , Naples (Italy); Second University of Naples, Department of Medical, Surgical, Neurological, Metabolic and Aging Sciences, Naples (Italy); Esposito, Fabrizio [University of Salerno, Department of Medicine and Surgery, Baronissi (Salerno) (Italy); Maastricht University, Department of Cognitive Neuroscience, Maastricht (Netherlands)

    2016-02-15

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm{sup 2}, 54 gradient directions) and low angular resolution (b = 1000 s/mm{sup 2}, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  14. Q-ball imaging models: comparison between high and low angular resolution diffusion-weighted MRI protocols for investigation of brain white matter integrity

    International Nuclear Information System (INIS)

    Q-ball imaging (QBI) is one of the typical data models for quantifying white matter (WM) anisotropy in diffusion-weighted MRI (DwMRI) studies. Brain and spinal investigation by high angular resolution DwMRI (high angular resolution imaging (HARDI)) protocols exhibits higher angular resolution in diffusion imaging compared to low angular resolution models, although with longer acquisition times. We aimed to assess the difference between QBI-derived anisotropy values from high and low angular resolution DwMRI protocols and their potential advantages or shortcomings in neuroradiology. Brain DwMRI data sets were acquired in seven healthy volunteers using both HARDI (b = 3000 s/mm2, 54 gradient directions) and low angular resolution (b = 1000 s/mm2, 32 gradient directions) acquisition schemes. For both sequences, tract of interest tractography and generalized fractional anisotropy (GFA) measures were extracted by using QBI model and were compared between the two data sets. QBI tractography and voxel-wise analyses showed that some WM tracts, such as corpus callosum, inferior longitudinal, and uncinate fasciculi, were reconstructed as one-dominant-direction fiber bundles with both acquisition schemes. In these WM tracts, mean percent different difference in GFA between the two data sets was less than 5 %. Contrariwise, multidirectional fiber bundles, such as corticospinal tract and superior longitudinal fasciculus, were more accurately depicted by HARDI acquisition scheme. Our results suggest that the design of optimal DwMRI acquisition protocols for clinical investigation of WM anisotropy by QBI models should consider the specific brain target regions to be explored, inducing researchers to a trade-off choice between angular resolution and acquisition time. (orig.)

  15. High angular resolution diffusion imaging in a child with autism spectrum disorder and comparison with his unaffected identical twin.

    Science.gov (United States)

    Conti, Eugenia; Pannek, Kerstin; Calderoni, Sara; Gaglianese, Anna; Fiori, Simona; Brovedani, Paola; Scelfo, Danilo; Rose, Stephen; Tosetti, Michela; Cioni, Giovanni; Guzzetta, Andrea

    2015-01-01

    In recent years, the use of brain diffusion MRI has led to the hypothesis that children with autism spectrum disorder (ASD) show abnormally connected brains. We used the model of disease-discordant identical twins to test the hypothesis that higher-order diffusion MRI protocols are able to detect abnormal connectivity in a single subject. We studied the structural connectivity of the brain of a child with ASD, and of that of his unaffected identical twin, using high angular resolution diffusion imaging (HARDI) probabilistic tractography. Cortical regions were automatically parcellated from high-resolution structural images, and HARDI-based connection matrices were produced for statistical comparison. Differences in diffusion indexes between subjects were tested by Wilcoxon signed rank test. Tracts were defined as discordant when they showed a between-subject difference of 10 percent or more. Around 11 percent of the discordant intra-hemispheric tracts showed lower fractional anisotropy (FA) values in the ASD twin, while only 1 percent showed higher values. This difference was significant. Our findings in a disease-discordant identical twin pair confirm previous literature consistently reporting lower FA values in children with ASD. PMID:26446271

  16. Towards optical intensity interferometry for high angular resolution stellar astrophysics

    CERN Document Server

    Nunez, Paul D

    2012-01-01

    Most neighboring stars are still detected as point sources and are beyond the angular resolution reach of current observatories. Methods to improve our understanding of stars at high angular resolution are investigated. Air Cherenkov telescopes (ACTs), primarily used for Gamma-ray astronomy, enable us to increase our understanding of the circumstellar environment of a particular system. When used as optical intensity interferometers, future ACT arrays will allow us to detect stars as extended objects and image their surfaces at high angular resolution. Optical stellar intensity interferometry (SII) with ACT arrays, composed of nearly 100 telescopes, will provide means to measure fundamental stellar parameters and also open the possibility of model-independent imaging. A data analysis algorithm is developed and permits the reconstruction of high angular resolution images from simulated SII data. The capabilities and limitations of future ACT arrays used for high angular resolution imaging are investigated via ...

  17. The Wide-Field Imaging Interferometry Testbed: Enabling Techniques for High Angular Resolution Astronomy

    Science.gov (United States)

    Rinehart, S. A.; Armstrong, T.; Frey, Bradley J.; Jung, J.; Kirk, J.; Leisawitz, David T.; Leviton, Douglas B.; Lyon, R.; Maher, Stephen; Martino, Anthony J.; Pauls, T.

    2007-01-01

    The Wide-Field Imaging Interferometry Testbed (WIIT) was designed to develop techniques for wide-field of view imaging interferometry, using "double-Fourier" methods. These techniques will be important for a wide range of future spacebased interferometry missions. We have provided simple demonstrations of the methodology already, and continuing development of the testbed will lead to higher data rates, improved data quality, and refined algorithms for image reconstruction. At present, the testbed effort includes five lines of development; automation of the testbed, operation in an improved environment, acquisition of large high-quality datasets, development of image reconstruction algorithms, and analytical modeling of the testbed. We discuss the progress made towards the first four of these goals; the analytical modeling is discussed in a separate paper within this conference.

  18. High-angular-resolution stellar imaging with occultations from the Cassini spacecraft - III. Mira

    Science.gov (United States)

    Stewart, Paul N.; Tuthill, Peter G.; Nicholson, Philip D.; Hedman, Matthew M.

    2016-04-01

    We present an analysis of spectral and spatial data of Mira obtained by the Cassini spacecraft, which not only observed the star's spectra over a broad range of near-infrared wavelengths, but was also able to obtain high-resolution spatial information by watching the star pass behind Saturn's rings. The observed spectral range of 1-5 microns reveals the stellar atmosphere in the crucial water-bands which are unavailable to terrestrial observers, and the simultaneous spatial sampling allows the origin of spectral features to be located in the stellar environment. Models are fitted to the data, revealing the spectral and spatial structure of molecular layers surrounding the star. High-resolution imagery is recovered revealing the layered and asymmetric nature of the stellar atmosphere. The observational data set is also used to confront the state-of-the-art cool opacity-sampling dynamic extended atmosphere models of Mira variables through a detailed spectral and spatial comparison, revealing in general a good agreement with some specific departures corresponding to particular spectral features.

  19. A super-high angular resolution principle for coded-mask X-ray imaging beyond the diffraction limit of a single pinhole

    Institute of Scientific and Technical Information of China (English)

    Chen Zhang; Shuang-Nan Zhang

    2009-01-01

    High angular resolution X-ray imaging is always useful in astrophysics and solar physics. In principle, it can be performed by using coded-mask imaging with a very long mask-detector distance. Previously, the diffraction-interference effect was thought to degrade coded-mask imaging performance dramatically at the low energy end with its very long mask-detector distance. The diffraction-interference effect is described with numerical calculations, and the difffraction-interference cross correlation reconstruction method (DICC) is developed in order to overcome the imaging performance degradation. Based on the DICC, a super-high angular resolution principle (SHARP) for coded-mask X-ray imaging is proposed. The feasibility of coded mask imaging beyond the diffraction limit of a single pinhole is demonstrated with simulations. With the specification that the mask element size is 50 × 50 μm2 and the mask-detector distance is 50 m, the achieved angular resolution is 0.32arcsec above about 10keV and 0.36arcsec at 1.24keV (λ = 1 nm), where diffraction cannot be neglected. The on-axis source location accuracy is better than 0.02 arcsec. Potential applications for solar observations and wide-field X-ray monitors are also briefly discussed.

  20. Angular resolution of a neutron scatter imaging system%中子散射成像探测角分辨研究∗

    Institute of Scientific and Technical Information of China (English)

    张美; 张显鹏; 李奎念; 盛亮; 袁媛; 宋朝晖; 李阳

    2015-01-01

    Using a combination of imaging and spectroscopic capabilities, neutron scatter imaging is a novel method of detecting neutrons in an energy range from 1 to 20 MeV. The technique can be applied to measurements in a variety of areas, including solar and atmospheric physics, radiation therapy, and nuclear materials monitoring. Angular resolution is an important parameter for a neutron scatter imaging system. There are some factors causing the uncertainty in the reconstructed image due to the imperfection of the detector system and natures of neutron scattering. These factors mainly are the uncertainties of the position and the energy. In this paper, the contributions of these factors to the angular resolution are discussed. The results show that the angular resolution varies with scatter angle; the position uncertainty not only directly affects the angular resolution, but also indirectly contributes to the angular uncertainty by influencing energy uncertainty; when the detector dimension is less than 5 cm, the energy uncertainty becomes a dominating factor for angular resolution. The prototype is designed based on the above analysis results. The angular resolution of the designed prototype is tested on Cf252 source. The experimental results are basically consistent with the simulation results.%中子散射成像技术是近年来国外正在发展的一项新型辐射成像技术,在深空宇宙探测、核材料监控等方面具有广阔的应用前景。角分辨是衡量该技术成像能力的一项重要参数。研究了位置不确定度和能量分辨对角分辨的影响。理论分析表明:以不同角度散射,成像的角分辨不同;位置不确定不仅直接影响角分辨,还通过影响能量不确定度对角分辨间接贡献;位置分辨主要来源于探测器的结构尺寸,当探测器尺寸小于5 cm,影响角分辨的主要来源是能量不确定度。利用所获得的理论结果指导设计了原理探测系统,并对设计的原

  1. Ghost Imaging Using Orbital Angular Momentum

    Institute of Scientific and Technical Information of China (English)

    赵生妹; 丁建; 董小亮; 郑宝玉

    2011-01-01

    We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum. In the signal arm, object spatial information is encoded as a phase matrix. For an N-grey-scale object, different phase matrices, varying from 0 to K with increment n/N, are used for different greyscales, and then they are modulated to a signal beam by a spatial light modulator. According to the conservation of the orbital angular momentum in the ghost imaging system, these changes will give different coincidence rates in measurement, and hence the object information can be extracted in the idler arm. By simulations and experiments, the results show that our scheme can improve the resolution of the image effectively. Compared with another encoding method using orbital angular momentum, our scheme has a better performance for both characters and the image object.%We present a novel encoding scheme in a ghost-imaging system using orbital angular momentum.In the signal arm,object spatial information is encoded as a phase matrix.For an N-grey-scale object,different phase matrices,varying from 0 to π with increment π/N,are used for different greyscales,and then they are modulated to a signal beam by a spatial light modulator.According to the conservation of the orbital angular momentum in the ghost imaging system,these changes will give different coincidence rates in measurement,and hence the object information can be extracted in the idler arm.By simulations and experiments,the results show that our scheme can improve the resolution of the image effectively.Compared with another encoding method using orbital angular momentum,our scheme has a better performance for both characters and the image object.

  2. Angular resolution of stacked resistive plate chambers

    CERN Document Server

    Samuel, Deepak; Murgod, Lakshmi P

    2016-01-01

    We present here detailed derivations of mathematical expressions for the angular resolution of a set of stacked resistive plate chambers (RPCs). The expressions are validated against experimental results using data collected from the prototype detectors (without magnet) of the upcoming India-based Neutrino Observatory (INO). In principle, these expressions can be used for any other detector with an architecture similar to that of RPCs.

  3. High-angular Resolution Laser Threat Warner

    Directory of Open Access Journals (Sweden)

    Sushil Kumar

    2007-07-01

    Full Text Available In this paper, the design and development aspects of a high-angular resolution laser-threat Warner developed at the Laser Science & Technology Centre (LASTEC, Delhi are presented. It describes a high-angular resolution laser-threat warner capable of giving warning with a resolution of i 3" when it is exposed to laser radiation from visible and near-IR pulsed solid-state laser source. It has a field of view of 90' in the azimuth direction, whereas the elevation coverage is between -5" and + 25". It is capable of handling multiple types of laser threats covering wavelength from 400 nm to 1100 nm and has an operational range of 4 km for a Q-switched laser source energy (10 ns of 10 mJ/pulse and output beam divergence of 1 mrad. The paper also describes its simulated evaluation process and field-testing which it has undergone. The result of field-testing confirms that it meets all its performance specifications mentioned above.

  4. The 2008 outburst in the Young Stellar System Z CMa. III - Multi-epoch high-angular resolution images and spectra of the components in near-infrared

    CERN Document Server

    Bonnefoy, M; Dougados, C; Kospal, A; Benisty, M; Duchene, G; Bouvier, J; Garcia, P J V; Whelan, E; Antoniucci, S; Podio, L

    2016-01-01

    Z CMa is a complex pre-main sequence binary with a current separation of 100 mas, known to consist of an FU Orionis star (SE component) and an embedded Herbig Be star (NW component). Immediately when the late-2008 outburst of Z CMa was announced to the community, we initiated a high angular resolution imaging campaign with VLT/NaCo, Keck/NIRC2, VLT/SINFONI, and Keck/OSIRIS which aimed at characterizing the outburst of both components of the system in the near-infrared. We confirm that the NW star dominates the system flux in the 1.1-3.8 microns range and is responsible for the photometric outburst. We extract the first medium-resolution (R=2000-4000) near-infrared (1.1-2.4 microns) spectra of the individual components during and after the outburst. The SE component has a spectrum typical of FU Orionis objects. The NW component spectrum is characteristic of embedded outbursting protostars and EX Or objects. It displays numerous emission lines during the outburst whose intensity correlates with the system activ...

  5. High Angular Resolution Imaging Spectroscopy of the Galactic Ultra-Compact HII Region K3-50A

    CERN Document Server

    Blum, Robert D

    2009-01-01

    Gemini North adaptive optics imaging spectroscopy is presented for the Galactic ultra-compact HII (UCHII) region K3-50A. Data were obtained in the K-band using the Near-infrared Integral Field Spectrograph (NIFS) behind the facility adaptive optics module ALTAIR in natural guide star mode. The NIFS data cube reveals a complex spatial morphology across the 0.1 pc scale of the 3'' UCHII region. Comparison of the nebular emission to Cloudy ionization models shows that the central source must have an effective temperature between about 37000 K and 45000 K with preferred values near 40000 K. Evidence is presented for sharp density variations in the nebula which are interpreted as a clearing of material nearest the central source. High excitation lines of FeIII and SeIV show that the ionization of the nebula clearly changes with distance from the central source. A double lobed kinematic signature (+/- 25 kms) is evident in the Br gamma line map which may be related to the larger scale ionized flow detailed in earli...

  6. B[e] stars at the highest angular resolution: the case of HD87643

    CERN Document Server

    Millour, Florentin; Borges-Fernandes, Marcelo; Meilland, Anthony

    2009-01-01

    New results on the B[e] star HD87643 are presented here. They were obtained with a wide range of di?erent instruments, from wide-?eld imaging with the WFI camera, high resolution spectroscopy with the FEROS instrument, high angular resolution imaging with the adaptive optics camera NACO, to the highest angular resolution available with AMBER on the VLTI. We report the detection of a companion to HD87643 with AMBER, subsequently con?rmed in the NACO data. Implications of that discovery to some of the previously di?cult-to-understand data-sets are then presented.

  7. Improving the H.E.S.S. angular resolution using the Disp method

    CERN Document Server

    Lu, C -C

    2013-01-01

    The angular resolution of imaging atmospheric Cherenkov telescopes depends on the employed event reconstruction methods. By taking the weighted average of intersections of shower axes, the H.E.S.S. experiment achieves a 0.08 degree angular resolution at 20 degree zenith angle with an image size cut of 160 p.e. for sources with a spectral index of 2. However, the angular resolution degrades to 0.14 degree at 60 degree zenith angle, due to the larger fraction of nearly parallel images. The Disp method reduces the impact of parallel images by including an estimation of the image displacement (disp), inferred from the Hillas parameters, in the reconstruction procedure. By using this technique, the angular resolution at large zenith angles can be improved by 50%. An additional cut on the estimated direction uncertainty can further improve the angular resolution to around 0.05 degrees at the expense of a loss of 50% of effective area. The performance of this reconstruction method on simulated gamma-ray events and r...

  8. High angular resolution SZ observations with NIKA and NIKA2

    CERN Document Server

    Comis, B; Ade, P; André, P; Arnaud, M; Bartalucci, I; Beelen, A; Benoît, A; Bideaud, A; Billot, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; Désert, F -X; Doyle, S; Goupy, J; Kramer, C; Lagache, G; Leclercq, S; Macías-Pérez, J F; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Pisano, G; Ponthieu, N; Pratt, G W; Revéret, V; Ritacco, A; Rodriguez, L; Romero, C; Ruppin, F; Savini, G; Schuster, K; Sievers, A; Triqueneaux, S; Tucker, C; Zilch, R

    2016-01-01

    NIKA2 (New IRAM KID Arrays) is a dual band (150 and 260 GHz) imaging camera based on Kinetic Inductance Detectors (KIDs) and designed to work at the IRAM 30 m telescope (Pico Veleta, Spain). Built on the experience of the NIKA prototype, NIKA2 has been installed at the 30 m focal plane in October 2015 and the commissioning phase is now ongoing. Through the thermal Sunyaev-Zeldovich (tSZ) effect, NIKA2 will image the ionized gas residing in clusters of galaxies with a resolution of 12 and 18 arcsec FWHM (at 150 and 260 GHz, respectively). We report on the recent tSZ measurements with the NIKA camera and discuss the future objectives for the NIKA2 SZ large Program, 300h of observation dedicated to SZ science. With this program we intend to perform a high angular resolution follow-up of a cosmologically-representative sample of clusters belonging to SZ catalogues, with redshift greater than 0.5. The main output of the program will be the study of the redshift evolution of the cluster pressure profile as well as ...

  9. PKS 1502+106: A high-redshift Fermi blazar at extreme angular resolution. Structural dynamics with VLBI imaging up to 86 GHz

    CERN Document Server

    Karamanavis, V; Krichbaum, T P; Angelakis, E; Hodgson, J; Nestoras, I; Myserlis, I; Zensus, J A; Sievers, A; Ciprini, S

    2016-01-01

    Context. Blazars are among the most energetic objects in the Universe. In 2008 August, Fermi/LAT detected the blazar PKS 1502+106 showing a rapid and strong gamma-ray outburst followed by high and variable flux over the next months. This activity at high energies triggered an intensive multi-wavelength campaign covering also the radio, optical, UV, and X-ray bands indicating that the flare was accompanied by a simultaneous outburst at optical/UV/X-rays and a delayed outburst at radio bands. Aims: In the current work we explore the phenomenology and physical conditions within the ultra-relativistic jet of the gamma-ray blazar PKS 1502+106. Additionally, we address the question of the spatial localization of the MeV/GeV-emitting region of the source. Methods: We utilize ultra-high angular resolution mm-VLBI observations at 43 and 86 GHz complemented by VLBI observations at 15 GHz. We also employ single-dish radio data from the F-GAMMA program at frequencies matching the VLBI monitoring. Results: PKS 1502+106 sh...

  10. 高分辨力面阵图像式光电编码器的测角技术%Angular measurement technology for high resolution area array image optical encoder

    Institute of Scientific and Technical Information of China (English)

    齐荔荔; 万秋华

    2013-01-01

    In order to realize the miniaturization and high resolution of area array image optical encoder, this paper studies the code disc encoding of the area array image optical encoder and the fine code subdivision algorithm based on image processing technology. Firstly, according to the specification of the optical encoder, corresponding dimension of code disc is designed. Secondly, an image sensor is used to capture the code disc pattern while the shaft rotates; a microprocessor is used to receive the image data; pattern recognition algorithm is used to obtain the coarse code; and the improved baseline centroid algorithm is used to calculate the fine code angular information in sub-pixel level. Finally , the coarse code and fine code are combined to compose the optical encoder angular output data. An area array image optical encoder with diameter of f 45 mm was designed, and experiment was carried out. Experiment result indicates that without any additional optical lens, adopting the proposed fine code subdivision technique, the encoder angular resolution reaches 5 arcseconds and the number of subdivision of 4 096 is achieved; the peak to peak value of the angular measurement error is 61 arcseconds. The area array image optical encoder and fine code subdivision technique could improve the encoder resolution, and reduce the volume and weight of the encoder, which meet the demand of miniaturized optical encoder in aeronautic and astronautic field.%为实现面阵图像式光电编码器的小型化及高分辨力,研究了面阵图像式光电编码器的码盘编码和基于图像处理技术的精码细分算法.首先根据光电编码器的性能指标要求设计相应的码盘尺寸;然后通过图像传感器采集随轴系转动的码盘图样;微处理器接收图像数据,通过图形识别算法得到粗码角度,并采用改进的基准线质心算法,计算亚像素级的精码角度信息.最后由粗码和精码组成光电编码器测角数据.实验

  11. Spatial Angular Compounding of Photoacoustic Images.

    Science.gov (United States)

    Kang, Hyun Jae; Bell, Muyinatu A Lediju; Guo, Xiaoyu; Boctor, Emad M

    2016-08-01

    Photoacoustic (PA) images utilize pulsed lasers and ultrasound transducers to visualize targets with higher optical absorption than the surrounding medium. However, they are susceptible to acoustic clutter and background noise artifacts that obfuscate biomedical structures of interest. We investigated three spatial-angular compounding methods to improve PA image quality for biomedical applications, implemented by combining multiple images acquired as an ultrasound probe was rotated about the elevational axis with the laser beam and target fixed. Compounding with conventional averaging was based on the pose information of each PA image, while compounding with weighted and selective averaging utilized both the pose and image content information. Weighted-average compounding enhanced PA images with the least distortion of signal size, particularly when there were large (i.e., 2.5 mm and 7 (°)) perturbations from the initial probe position. Selective-average compounding offered the best improvement in image quality with up 181, 1665, and 1568 times higher contrast, CNR, and SNR, respectively, compared to the mean values of individual PA images. The three presented spatial compounding methods have promising potential to enhance image quality in multiple photoacoustic applications. PMID:26890642

  12. Angular resolution of space-based gravitational wave detectors

    International Nuclear Information System (INIS)

    Proposed space-based gravitational wave antennas involve satellites arrayed either in an equilateral triangle around the Earth in the ecliptic plane (the ecliptic-plane option) or in an equilateral triangle orbiting the Sun in such a way that the plane of the triangle is tilted at 60 deg, relative to the ecliptic (the precessing-plane option). In this paper, we explore the angular resolution of these two classes of detectors for two kinds of sources (essentially monochromatic compact binaries and coalescing massive-black-hole binaries) using time-domain expressions for the gravitational waveform that are accurate to 4/2 PN order. Our results display an interesting effect not previously reported in the literature, and particularly underline the importance of including the higher-order PN terms in the waveform when predicting the angular resolution of ecliptic-plane detector arrays

  13. Statistical Angular Resolution Limit for Ultrawideband MIMO Noise Radar

    Directory of Open Access Journals (Sweden)

    Xiaoli Zhou

    2015-01-01

    Full Text Available The two-dimensional angular resolution limit (ARL of elevation and azimuth for MIMO radar with ultrawideband (UWB noise waveforms is investigated using statistical resolution theory. First, the signal model of monostatic UWB MIMO noise radar is established in a 3D reference frame. Then, the statistical angular resolution limits (SARLs of two closely spaced targets are derived using the detection-theoretic and estimation-theoretic approaches, respectively. The detection-theoretic approach is based on the generalized likelihood ratio test (GLRT with given probabilities of false alarm and detection, while the estimation-theoretic approach is based on Smith’s criterion which involves the Cramér-Rao lower bound (CRLB. Furthermore, the relationship between the two approaches is presented, and the factors affecting the SARL, that is, detection parameters, transmit waveforms, array geometry, signal-to-noise ratio (SNR, and parameters of target (i.e., radar cross section (RCS and direction, are analyzed. Compared with the conventional radar resolution theory defined by the ambiguity function, the SARL reflects the practical resolution ability of radar and can provide an optimization criterion for radar system design.

  14. Cepheids at high angular resolution: circumstellar envelope and pulsation

    Science.gov (United States)

    Gallenne, Alexandre

    2011-12-01

    In 2005, interferometric observations with VLTI/VINCI and CHARA/FLUOR revealed the existence of a circumstellar envelope (CSE) around some Cepheids. This surrounding material is particularly interesting for two reasons: it could have an impact on the distance estimates and could be linked to a past or on-going mass loss. The use of Baade-Wesselink methods for independent distance determinations could be significantly biased by the presence of these envelopes. Although their observations are difficult because of the high contrast between the photosphere of the star and the CSE, several observation techniques have the potential to improve our knowledge about their physical properties. In this thesis, I discuss in particular high angular resolution techniques that I applied to the study of several bright Galactic Cepheids. First, I used adaptive optic observations with NACO of the Cepheid RS Puppis, in order to deduce the flux ratio between the CSE and the photosphere of the star. In addition, I could carry out a statistical study of the speckle noise and inspect a possible asymmetry. Secondly, I analysed VISIR data to study the spectral energy distribution of a sample of Cepheids. These diffraction-limited images enabled me to carry out an accurate photometry in the N band and to detect an IR excess linked to the presence of a circumstellar component. On the other hand, applying a Fourier analysis I showed that some components are resolved. I then explored the K' band with the recombination instrument FLUOR for some bright Cepheids. Thanks to new set of data of Y Oph, I improved the study of its circumstellar envelope, using a ring-like model for the CSE. For two other Cepheids, U Vul and S Sge, I applied the interferometric Baade-Wesselink method in order to estimate their distance.

  15. Effects of angular range on image quality of chest digital tomosynthesis

    Science.gov (United States)

    Lee, Haenghwa; Kim, Ye-seul; Choi, Sunghoon; Lee, Dong-Hoon; Choi, Seungyeon; Kim, Hee-Joung

    2016-03-01

    Chest digital tomosynthesis (CDT) is a new 3D imaging technique that can be expected to improve clinical diagnosis over conventional chest radiography. We investigated the effect of the angular range of data acquisition on the image quality using newly developed CDT system. The four different acquisition sets were studied using +/-15°, +/-20°, +/-30°, and +/-35° angular ranges with 21 projection views (PVs). The point spread function (PSF), modulation transfer function (MTF), artifact spread function (ASF), and normalized contrast-to-noise ratio (CNR) were used to evaluate the image quality. We found that increasing angular ranges improved vertical resolution. The results indicated that there was the opposite relationship of the CNR with angular range for the two tissue types. While CNR for heart tissue increased with increasing angular range, CNR for spine bone decreased. The results showed that the angular range is an important parameter for the CDT exam.

  16. Astronomy at high angular resolution a compendium of techniques in the visible and near-infrared

    CERN Document Server

    Hussain, Gaitee; Berger, Jean-Philippe; Schmidtobreick, Linda

    2016-01-01

    This book offers an essential compendium of astronomical high-resolution techniques. Recent years have seen considerable developments in such techniques, which are critical to advances in many areas of astronomy. As reflected in the book, these techniques can be divided into direct methods, interferometry, and reconstruction methods, and can be applied to a huge variety of astrophysical systems, ranging from planets, single stars and binaries to active galactic nuclei, providing angular resolution in the micro- to tens of milliarcsecond scales. Written by experts in their fields, the chapters cover adaptive optics, aperture masking imaging, spectra disentangling, interferometry, lucky imaging, Roche tomography, imaging with interferometry, interferometry of AGN, AGN reverberation mapping, Doppler- and magnetic imaging of stellar surfaces, Doppler tomography, eclipse mapping, Stokes imaging, and stellar tomography. This book is intended to enable a next generation of astronomers to apply high-resolution techni...

  17. Systematics in Metallicity Gradient Measurements I : Angular Resolution, Signal-to-Noise and Annuli Binning

    CERN Document Server

    Yuan, T -T; Rich, J

    2013-01-01

    With the rapid progress in metallicity gradient studies at high-redshift, it is imperative that we thoroughly understand the systematics in these measurements. This work investigates how the [NII]/Halpha ratio based metallicity gradients change with angular resolution, signal-to-noise (S/N), and annular binning parameters. Two approaches are used: 1. We downgrade the high angular resolution integral-field data of a gravitationally lensed galaxy and re-derive the metallicity gradients at different angular resolution; 2. We simulate high-redshift integral field spectroscopy (IFS) observations under different angular resolution and S/N conditions using a local galaxy with a known gradient. We find that the measured metallicity gradient changes systematically with angular resolution and annular binning. Seeing-limited observations produce significantly flatter gradients than higher angular resolution observations. There is a critical angular resolution limit beyond which the measured metallicity gradient is subst...

  18. High Angular Resolution JHK Imaging of the Centers of the Metal-Poor Globular Clusters NGC5272 (M3), NGC6205 (M13), NGC6287, and NGC6341 (M92)

    CERN Document Server

    Davidge, T J

    1998-01-01

    The Canada-France-Hawaii Telescope (CFHT) Adaptive Optics Bonnette (AOB) has been used to obtain high angular resolution JHK images of the centers of the metal-poor globular clusters NGC5272 (M3), NGC6205 (M13), NGC6287, and NGC6341 (M92). The color-magnitude diagrams (CMDs) derived from these data include the upper main sequence and most of the red giant branch (RGB), and the cluster sequences agree with published photometric measurements of bright stars in these clusters. The photometric accuracy is limited by PSF variations, which introduce systematic errors of a few hundredths of a magnitude near the AO reference star. The clusters are paired according to metallicity, and the near-infrared CMDs and luminosity functions are used to investigate the relative ages within each pair. The near-infrared CMDs provide the tightest constraints on the relative ages of the classical second parameter pair NGC5272 and NGC6205, and indicate that these clusters have ages that differ by no more than +/- 1 Gyr. These result...

  19. MEASUREMENT OF ANGULAR VIBRATION AMPLITUDE BY ACTIVELY BLURRED IMAGES

    Institute of Scientific and Technical Information of China (English)

    GUAN Baiqing; WANG Shigang; LIU Chong; LI Qian

    2007-01-01

    A novel motion-blur-based method for measuring the angular amplitude of a high-frequency rotational vibration is schemed. The proposed approach combines the active vision concept and the mechanism of motion-from-blur, generates motion blur on the image plane actively by extending exposure time, and utilizes the motion blur information in polar images to estimate the angular amplitude of a high-frequency rotational vibration. This method obtains the analytical results of the angular vibration amplitude from the geometric moments of a motion blurred polar image and an unblurred image for reference. Experimental results are provided to validate the presented scheme.

  20. Method for improving the angular resolution of a neutron scatter camera

    Science.gov (United States)

    Mascarenhas, Nicholas; Marleau, Peter; Gerling, Mark; Cooper, Robert Lee; Mrowka, Stanley; Brennan, James S.

    2012-12-25

    An instrument that will directly image the fast fission neutrons from a special nuclear material source wherein the neutron detection efficiency is increased has been described. Instead of the previous technique that uses a time-of-flight (TOF) between 2 widely spaced fixed planes of neutron detectors to measure scatter neutron kinetic energy, we now use the recoil proton energy deposited in the second of the 2 scatter planes which can now be repositioned either much closer together or further apart. However, by doubling the separation distance between the 2 planes from 20 cm to a distance of 40 cm we improved the angular resolution of the detector from about 12.degree. to about 10.degree.. A further doubling of the separation distance to 80 cm provided an addition improvement in angular resolution of the detector to about 6.degree. without adding additional detectors or ancillary electronics. The distance between planes also may be dynamically changed using a suitable common technique such as a gear- or motor-drive to toggle between the various positions. The angular resolution of this new configuration, therefore, is increased at the expanse of detection sensitivity. However, the diminished sensitivity may be acceptable for those applications where the detector is able to interrogate a particular site for an extended period.

  1. High angular resolution SZ observations with NIKA and NIKA2

    OpenAIRE

    Comis, B.; Adam, R.; Ade, P.; André, P.; Arnaud, M; Bartalucci, I.; A. Beelen; Benoît, A.; Bideaud, A.; Billot, N.; Bourrion, O.; Calvo, M.; Catalano, A; Coiffard, G.; Désert, F. -X.

    2016-01-01

    NIKA2 (New IRAM KID Arrays) is a dual band (150 and 260 GHz) imaging camera based on Kinetic Inductance Detectors (KIDs) and designed to work at the IRAM 30 m telescope (Pico Veleta, Spain). Built on the experience of the NIKA prototype, NIKA2 has been installed at the 30 m focal plane in October 2015 and the commissioning phase is now ongoing. Through the thermal Sunyaev-Zeldovich (tSZ) effect, NIKA2 will image the ionized gas residing in clusters of galaxies with a resolution of 12 and 18 a...

  2. Cepheids at high angular resolution: circumstellar envelope and pulsation

    CERN Document Server

    Gallenne, Alexandre

    2011-01-01

    In 2005, interferometric observations with VLTI/VINCI and CHARA/FLUOR revealed the existence of a circumstellar envelope (CSE) around some Cepheids. This surrounding material is particularly interesting for two reasons: it could have an impact on the distance estimates and could be linked to a past or on-going mass loss. The use of Baade-Wesselink methods for independent distance determinations could be significantly biased by the presence of these envelopes. Although their observations are difficult because of the high contrast between the photosphere of the star and the CSE, several observation techniques have the potential to improve our knowledge about their physical properties. In this thesis, I discuss in particular high angular resolution techniques that I applied to the study of several bright Galactic Cepheids. First, I used adaptive optic observations with NACO of the Cepheid RS Puppis, in order to deduce the flux ratio between the CSE and the photosphere of the star. In addition, I could carry out ...

  3. Low Power Compact Radio Galaxies at High Angular Resolution

    Energy Technology Data Exchange (ETDEWEB)

    Giroletti, Marcello; Giovannini, G.; /Bologna U. /Bologna, Ist. Radioastronomia; Taylor, G.B.; /KIPAC, Menlo Park /NRAO, Socorro

    2005-06-30

    We present sub-arcsecond resolution multi-frequency (8 and 22 GHz) VLA images of five low power compact (LPC) radio sources, and phase referenced VLBA images at 1.6 GHz of their nuclear regions. At the VLA resolution we resolve the structure and identify component positions and flux densities. The phase referenced VLBA data at 1.6 GHz reveals flat-spectrum, compact cores (down to a few milliJansky) in four of the five sources. The absolute astrometry provided by the phase referencing allows us to identify the center of activity on the VLA images. Moreover, these data reveal rich structures, including two-sided jets and secondary components. On the basis of the arcsecond scale structures and of the nuclear properties, we rule out the presence of strong relativistic effects in our LPCs, which must be intrinsically small (deprojected linear sizes {approx}< 10 kpc). Fits of continuous injection models reveal break frequencies in the GHz domain, and ages in the range 10{sup 5}-10{sup 7} yrs. In LPCs, the outermost edge may be advancing more slowly than in more powerful sources or could even be stationary; some LPCs might also have ceased their activity. In general, the properties of LPCs can be related to a number of reasons, including, but not limited to: youth, frustration, low kinematic power jets, and short-lived activity in the radio.

  4. Microsphere Super-resolution Imaging

    OpenAIRE

    Wang, Zengbo

    2015-01-01

    Recently, it was discovered that microsphere can generate super-resolution focusing beyond diffraction limit. This has led to the development of an exciting super-resolution imaging technique -microsphere nanoscopy- that features a record resolution of 50 nm under white lights. Different samples have been directly imaged in high resolution and real time without labelling, including both non-biological (nano devices, structures and materials) and biological (subcellular details, viruses) sampl...

  5. Simple Fourier optics formalism for high angular resolution systems and nulling interferometry

    CERN Document Server

    Henault, Francois

    2009-01-01

    In this paper are reviewed various designs of advanced, multi-aperture optical systems dedicated to high angular resolution imaging or to the detection of exo-planets by nulling interferometry. A simple Fourier optics formalism is presented, allowing to derive their imaging and nulling basic relationships as convolution or cross correlation products suitable for fast and accurate computation. The most promising designs seem to be the free-flying, axially recombined interferometers showing an unsurpassed imaging capacity, and a conceptual "super-resolving telescope" utilizing a mosaicing observation procedure. The entire study is only valid in the frame of first-order geometrical optics and scalar diffraction theory. Furthermore, it is assumed that all entrance sub-apertures are optically conjugated with their associated exit pupils, a particularity inducing an instrumental behaviour comparable with those of diffraction gratings.

  6. Imaging the Earth's Interior: the Angular Distribution of Terrestrial Neutrinos

    CERN Document Server

    Fields, Brian D

    2004-01-01

    Decays of radionuclides throughout the Earth's interior produce geothermal heat, but also are a source of antineutrinos. The (angle-integrated) geoneutrino flux places an integral constraint on the terrestrial radionuclide distribution. In this paper, we calculate the angular distribution of geoneutrinos, which opens a window on the differential radionuclide distribution. We develop the general formalism for the neutrino angular distribution, and we present the inverse transformation which recovers the terrestrial radioisotope distribution given a measurement of the neutrino angular distribution. Thus, geoneutrinos not only allow a means to image the Earth's interior, but offering a direct measure of the radioactive Earth, both (1) revealing the Earth's inner structure as probed by radionuclides, and (2) allowing for a complete determination of the radioactive heat generation as a function of radius. We present the geoneutrino angular distribution for the favored Earth model which has been used to calculate g...

  7. X-ray Interferometry with Transmissive Beam Combiners for Ultra-High Angular Resolution Astronomy

    Science.gov (United States)

    Skinner, G. K.; Krismanic, John F.

    2009-01-01

    Abstract Interferometry provides one of the possible routes to ultra-high angular resolution for X-ray and gamma-ray astronomy. Sub-micro-arc-second angular resolution, necessary to achieve objectives such as imaging the regions around the event horizon of a super-massive black hole at the center of an active galaxy, can be achieved if beams from parts of the incoming wavefront separated by 100s of meters can be stably and accurately brought together at small angles. One way of achieving this is by using grazing incidence mirrors. We here investigate an alternative approach in which the beams are recombined by optical elements working in transmission. It is shown that the use of diffractive elements is a particularly attractive option. We report experimental results from a simple 2-beam interferometer using a low-cost commercially available profiled film as the diffractive elements. A rotationally symmetric filled (or mostly filled) aperture variant of such an interferometer, equivalent to an X-ray axicon, is shown to offer a much wider bandpass than either a Phase Fresnel Lens (PFL) or a PFL with a refractive lens in an achromatic pair. Simulations of an example system are presented.

  8. Geometrically necessary dislocation densities in olivine obtained using high-angular resolution electron backscatter diffraction.

    Science.gov (United States)

    Wallis, David; Hansen, Lars N; Ben Britton, T; Wilkinson, Angus J

    2016-09-01

    Dislocations in geological minerals are fundamental to the creep processes that control large-scale geodynamic phenomena. However, techniques to quantify their densities, distributions, and types over critical subgrain to polycrystal length scales are limited. The recent advent of high-angular resolution electron backscatter diffraction (HR-EBSD), based on diffraction pattern cross-correlation, offers a powerful new approach that has been utilised to analyse dislocation densities in the materials sciences. In particular, HR-EBSD yields significantly better angular resolution (densities to be analysed. We develop the application of HR-EBSD to olivine, the dominant mineral in Earth's upper mantle by testing (1) different inversion methods for estimating geometrically necessary dislocation (GND) densities, (2) the sensitivity of the method under a range of data acquisition settings, and (3) the ability of the technique to resolve a variety of olivine dislocation structures. The relatively low crystal symmetry (orthorhombic) and few slip systems in olivine result in well constrained GND density estimates. The GND density noise floor is inversely proportional to map step size, such that datasets can be optimised for analysing either short wavelength, high density structures (e.g. subgrain boundaries) or long wavelength, low amplitude orientation gradients. Comparison to conventional images of decorated dislocations demonstrates that HR-EBSD can characterise the dislocation distribution and reveal additional structure not captured by the decoration technique. HR-EBSD therefore provides a highly effective method for analysing dislocations in olivine and determining their role in accommodating macroscopic deformation. PMID:27337604

  9. Microsphere Super-resolution Imaging

    CERN Document Server

    Wang, Zengbo

    2015-01-01

    Recently, it was discovered that microsphere can generate super-resolution focusing beyond diffraction limit. This has led to the development of an exciting super-resolution imaging technique -microsphere nanoscopy- that features a record resolution of 50 nm under white lights. Different samples have been directly imaged in high resolution and real time without labelling, including both non-biological (nano devices, structures and materials) and biological (subcellular details, viruses) samples. This chapter reviews the technique, which covers its background, fundamentals, experiments, mechanisms as well as the future outlook.

  10. Radiation length imaging with high resolution telescopes

    CERN Document Server

    Stolzenberg, U; Schwenker, B; Wieduwilt, P; Marinas, C; Lütticke, F

    2016-01-01

    The construction of low mass vertex detectors with a high level of system integration is of great interest for next generation collider experiments. Radiation length images with a sufficient spatial resolution can be used to measure and disentangle complex radiation length $X$/$X_0$ profiles and contribute to the understanding of vertex detector systems. Test beam experiments with multi GeV particle beams and high-resolution tracking telescopes provide an opportunity to obtain precise 2D images of the radiation length of thin planar objects. At the heart of the $X$/$X_0$ imaging is a spatially resolved measurement of the scattering angles of particles traversing the object under study. The main challenges are the alignment of the reference telescope and the calibration of its angular resolution. In order to demonstrate the capabilities of $X$/$X_0$ imaging, a test beam experiment has been conducted. The devices under test were two mechanical prototype modules of the Belle II vertex detector. A data sample of ...

  11. Understanding Active Galactic Nuclei using near-infrared high angular resolution polarimetry II: Preliminary results

    CERN Document Server

    Marin, F; Goosmann, R; Gratadour, D; Rouan, D; Clénet, Y; Pelat, D; Lobos, P Andrea Rojas

    2016-01-01

    In this second research note of a series of two, we present the first near-infrared results we obtained when modeling Active Galactic Nuclei (AGN). Our first proceedings showed the comparison between the MontAGN and STOKES Monte Carlo codes. Now we use our radiative transfer codes to simulate the polarization maps of a prototypical, NGC 1068-like, type-2 radio-quiet AGN. We produced high angular resolution infrared (1 micron) polarization images to be compared with recent observations in this wavelength range. Our preliminary results already show a good agreement between the models and observations but cannot account for the peculiar linear polarization angle of the torus such as observed. Gratadour et al. 2015 found a polarization position angle being perpendicular to the bipolar outflows axis. Further work is needed to improve the models by adding physical phenomena such as dichroism and clumpiness.

  12. Non Local Spatial and Angular Matching: Enabling higher spatial resolution diffusion MRI datasets through adaptive denoising.

    Science.gov (United States)

    St-Jean, Samuel; Coupé, Pierrick; Descoteaux, Maxime

    2016-08-01

    Diffusion magnetic resonance imaging (MRI) datasets suffer from low Signal-to-Noise Ratio (SNR), especially at high b-values. Acquiring data at high b-values contains relevant information and is now of great interest for microstructural and connectomics studies. High noise levels bias the measurements due to the non-Gaussian nature of the noise, which in turn can lead to a false and biased estimation of the diffusion parameters. Additionally, the usage of in-plane acceleration techniques during the acquisition leads to a spatially varying noise distribution, which depends on the parallel acceleration method implemented on the scanner. This paper proposes a novel diffusion MRI denoising technique that can be used on all existing data, without adding to the scanning time. We first apply a statistical framework to convert both stationary and non stationary Rician and non central Chi distributed noise to Gaussian distributed noise, effectively removing the bias. We then introduce a spatially and angular adaptive denoising technique, the Non Local Spatial and Angular Matching (NLSAM) algorithm. Each volume is first decomposed in small 4D overlapping patches, thus capturing the spatial and angular structure of the diffusion data, and a dictionary of atoms is learned on those patches. A local sparse decomposition is then found by bounding the reconstruction error with the local noise variance. We compare against three other state-of-the-art denoising methods and show quantitative local and connectivity results on a synthetic phantom and on an in-vivo high resolution dataset. Overall, our method restores perceptual information, removes the noise bias in common diffusion metrics, restores the extracted peaks coherence and improves reproducibility of tractography on the synthetic dataset. On the 1.2 mm high resolution in-vivo dataset, our denoising improves the visual quality of the data and reduces the number of spurious tracts when compared to the noisy acquisition. Our

  13. High-angular resolution observations of the Pistol Star

    CERN Document Server

    Martayan, Christophe; Bouquin, Jean-Baptiste Le; Merand, Antoine; Montagnier, Guillaume; Selman, Fernando; Girard, Julien; Fox, Andrew; Baade, Dietrich; Fremat, Yves; Lobel, Alex; Martins, Fabrice; Patru, Fabien; Rivinius, Thomas; Sana, Hugues; Stefl, Stan; Zorec, Jean; Semaan, Thierry

    2010-01-01

    First results of near-IR adaptive optics (AO)-assisted imaging, interferometry, and spectroscopy of this Luminous Blue Variable (LBV) are presented. They suggest that the Pistol Star is at least double. If the association is physical, it would reinforce questions concerning the importance of multiplicity for the formation and evolution of extremely massive stars.

  14. Angular resolution in underground detectors and a status report of the Soudan II nucleon decay detector

    International Nuclear Information System (INIS)

    This paper is a status report of the Soudan II honeycomb drift chamber project. It reports on the physics goals, present progress and future schedule of our experiment. It also includes a discussion of the angular resolution of cosmic ray muons which can be achieved in underground detectors, and in particular how to calibrate the resolution using the moon's shadow in cosmic rays. This last point has relevance in trying to understand the angular distributions in the reported observations of underground muons from Cygnus X-3. 12 refs., 9 figs

  15. Resolution enhancement in medical ultrasound imaging

    OpenAIRE

    Ploquin, Marie; Basarab, Adrian; Kouamé, Denis

    2015-01-01

    Image resolution enhancement is a problem of considerable interest in all medical imaging modalities. Unlike general purpose imaging or video processing, for a very long time, medical image resolution enhancement has been based on optimization of the imaging devices. Although some recent works purport to deal with image postprocessing, much remains to be done regarding medical image enhancement via postprocessing, especially in ultrasound imaging. We face a resolution improvement issue in the...

  16. Optimal method for exoplanet detection by angular differential imaging.

    Science.gov (United States)

    Mugnier, Laurent M; Cornia, Alberto; Sauvage, Jean-François; Rousset, Gérard; Fusco, Thierry; Védrenne, Nicolas

    2009-06-01

    We propose a novel method for the efficient direct detection of exoplanets from the ground using angular differential imaging. The method combines images appropriately, then uses the combined images jointly in a maximum-likelihood framework to estimate the position and intensity of potential planets orbiting the observed star. It takes into account the mixture of photon and detector noises and a positivity constraint on the planet's intensity. A reasonable detection criterion is also proposed based on the computation of the noise propagation from the images to the estimated intensity of the potential planet. The implementation of this method is tested on simulated data that take into account static aberrations before and after the coronagraph, residual turbulence after adaptive optics correction, and noise.

  17. First Results from High Angular Resolution ALMA Observations Toward the HL Tau Region

    CERN Document Server

    Partnership, ALMA; Perez, L M; Hunter, T R; Dent, W R F; Hales, A S; Hills, R; Corder, S; Fomalont, E B; Vlahakis, C; Asaki, Y; Barkats, D; Hirota, A; Hodge, J A; Impellizzeri, C M V; Kneissl, R; Liuzzo, E; Lucas, R; Marcelino, N; Matsushita, S; Nakanishi, K; Phillips, N; Richards, A M S; Toledo, I; Aladro, R; Broguiere, D; Cortes, J R; Cortes, P C; Dhawan, V; Espada, D; Galarza, F; Garcia-Appadoo, D; Guzman-Ramirez, L; Humphreys, E M; Jung, T; Kameno, S; Laing, R A; Leon, S; Marconi, G; Nikolic, B; Nyman, L -A; Radiszcz, M; Remijan, A; Rodon, J A; Sawada, T; Takahashi, S; Tilanus, R P J; Vilaro, B Vila; Watson, L C; Wiklind, T; Akiyama, E; Chapillon, E; de Gregorio, I; Di Francesco, J; Gueth, F; Kawamura, A; Lee, C -F; Luong, Q Nguyen; Mangum, J; Pietu, V; Sanhueza, P; Saigo, K; Takakuwa, S; Ubach, C; van Kempen, T; Wootten, A; Castro-Carrizo, A; Francke, H; Gallardo, J; Garcia, J; Gonzalez, S; Hill, T; Kaminski, T; Kurono, Y; Liu, H -Y; Lopez, C; Morales, F; Plarre, K; Schieven, G; Testi, L; Videla, L; Villard, E; Andreani, P; Hibbard, J E; Tatematsu, K

    2015-01-01

    We present Atacama Large Millimeter/submillimeter Array (ALMA) observations from the 2014 Long Baseline Campaign in dust continuum and spectral line emission from the HL Tau region. The continuum images at wavelengths of 2.9, 1.3, and 0.87 mm have unprecedented angular resolutions of 0.075 arcseconds (10 AU) to 0.025 arcseconds (3.5 AU), revealing an astonishing level of detail in the circumstellar disk surrounding the young solar analogue HL Tau, with a pattern of bright and dark rings observed at all wavelengths. By fitting ellipses to the most distinct rings, we measure precise values for the disk inclination (46.72pm0.05 degrees) and position angle (+138.02pm0.07 degrees). We obtain a high-fidelity image of the 1.0 mm spectral index ($\\alpha$), which ranges from $\\alpha\\sim2.0$ in the optically-thick central peak and two brightest rings, increasing to 2.3-3.0 in the dark rings. The dark rings are not devoid of emission, we estimate a grain emissivity index of 0.8 for the innermost dark ring and lower for ...

  18. Ghost imaging with entangled photons and orbital angular momentum

    Science.gov (United States)

    Padgett, Miles

    We utilise the position and orbital angular momentum (OAM) correlations between the signal and idler photons generated in the down-conversion process to obtain ghost images of a phase object. By using an OAM phase filter, which is non-local with respect to the object, the ghost images exhibit isotropic edge-enhancement. The strong spatial correlations between the signal and idler photons generated by spontaneous parametric downconversion have been widely utilised in many different imaging systems. The use of a scanning single element detector to recover the spatial information in the signal and idler beams fundamentally limits the detection efficiency of the imaging system to a maximum of 1/N where N is the number of pixels in the image. Our approach overcomes this limitation by replacing the scanning detector by an intensified CCD camera, therefore detecting all photons irrespective of their position within the image. Using a camera in this way, coupled with the OAM edge-enhancement and image reconstruction techniques allows us to obtain images of phase objects with an average of fewer than one photon per image pixel.

  19. Chiral resolution of spin angular momentum in linearly polarized and unpolarized light.

    Science.gov (United States)

    Hernández, R J; Mazzulla, A; Provenzano, C; Pagliusi, P; Cipparrone, G

    2015-11-20

    Linearly polarized (LP) and unpolarized (UP) light are racemic entities since they can be described as superposition of opposite circularly polarized (CP) components of equal amplitude. As a consequence they do not carry spin angular momentum. Chiral resolution of a racemate, i.e. separation of their chiral components, is usually performed via asymmetric interaction with a chiral entity. In this paper we provide an experimental evidence of the chiral resolution of linearly polarized and unpolarized Gaussian beams through the transfer of spin angular momentum to chiral microparticles. Due to the interplay between linear and angular momentum exchange, basic manipulation tasks, as trapping, spinning or orbiting of micro-objects, can be performed by light with zero helicity. The results might broaden the perspectives for development of miniaturized and cost-effective devices.

  20. Section on High Resolution Optical Imaging (HROI)

    Data.gov (United States)

    Federal Laboratory Consortium — The Section on High Resolution Optical Imaging (HROI) develops novel technologies for studying biological processes at unprecedented speed and resolution. Research...

  1. GravityCam: Higher Resolution Visible Wide-Field Imaging

    CERN Document Server

    Mackay, Craig; Steele, Iain

    2016-01-01

    The limits to the angular resolution achievable with conventional ground-based telescopes are unchanged over 70 years. Atmospheric turbulence limits image quality to typically ~1 arcsec in practice. We have developed a new concept of ground-based imaging instrument called GravityCam capable of delivering significantly sharper images from the ground than is normally possible without adaptive optics. The acquisition of visible images at high speed without significant noise penalty has been made possible by advances in optical and near IR imaging technologies. Images are recorded at high speed and then aligned before combination and can yield a 3-5 fold improvement in image resolution. Very wide survey fields are possible with widefield telescope optics. We describe GravityCam and detail its application to accelerate greatly the rate of detection of Earth size planets by gravitational microlensing. GravityCam will also improve substantially the quality of weak shear studies of dark matter distribution in distant...

  2. High-Resolution Imaging Spectrometer

    Science.gov (United States)

    Dozier, Jeff; Goetz, Alexander F. H.

    1990-01-01

    Earth resources observed in greater detail. High-Resolution Imaging Spectrometer, undergoing development for use in NASA's Earth Observing System, measures reflectance of Earth's surface in visible and near-infrared wavelengths. From an orbit around Earth, instrument scans surface of Earth in 200 wavelength bands simultaneously. Produces images enabling identification of minerals in rocks and soils, important algal pigments in oceans and inland waters, changes in spectra associated with biochemistry of plant canopies, compositions of atmospheric aerosols, sizes of grains in snow, and contamination of snow by impurities that absorb visible light.

  3. European Extremely Large Telescope Site Characterization II: High angular resolution parameters

    CERN Document Server

    Ramió, Héctor Vázquez; Muñoz-Tuñón, Casiana; Sarazin, Marc; Varela, Antonia M; Trinquet, Hervé; Delgado, José Miguel; Fuensalida, Jesús J; Reyes, Marcos; Benhida, Abdelmajid; Benkhaldoun, Zouhair; Lambas, Diego García; Hach, Youssef; Lazrek, M; Lombardi, Gianluca; Navarrete, Julio; Recabarren, Pablo; Renzi, Victor; Sabil, Mohammed; Vrech, Rubén

    2012-01-01

    This is the second article of a series devoted to European Extremely Large Telescope (E-ELT) site characterization. In this article we present the main properties of the parameters involved in high angular resolution observations from the data collected in the site testing campaign of the E-ELT during the Design Study (DS) phase. Observations were made in 2008 and 2009, in the four sites selected to shelter the future E-ELT (characterized under the ELT-DS contract): Aklim mountain in Morocco, Observatorio del Roque de los Muchachos (ORM) in Spain, Mac\\'on range in Argentina, and Cerro Ventarrones in Chile. The same techniques, instruments and acquisition procedures were taken on each site. A Multiple Aperture Scintillation Sensor (MASS) and a Differential Image Motion Monitor (DIMM) were installed at each site. Global statistics of the integrated seeing, the free atmosphere seeing, the boundary layer seeing and the isoplanatic angle were studied for each site, and the results are presented here. In order to e...

  4. High-resolution ophthalmic imaging system

    Science.gov (United States)

    Olivier, Scot S.; Carrano, Carmen J.

    2007-12-04

    A system for providing an improved resolution retina image comprising an imaging camera for capturing a retina image and a computer system operatively connected to the imaging camera, the computer producing short exposures of the retina image and providing speckle processing of the short exposures to provide the improved resolution retina image. The system comprises the steps of capturing a retina image, producing short exposures of the retina image, and speckle processing the short exposures of the retina image to provide the improved resolution retina image.

  5. Single Image Super-Resolution via L0 Image Smoothing

    OpenAIRE

    Zhang Liu; Qi Huang; Jian Li; Qi Wang

    2014-01-01

    We propose a single image super-resolution method based on a L0 smoothing approach. We consider a low-resolution image as two parts: one is the smooth image generated by the L0 smoothing method and the other is the error image between the low-resolution image and the smoothing image. We get an intermediate high-resolution image via a classical interpolation and then generate a high-resolution smoothing image with sharp edges by the L0 smoothing method. For the error image, a...

  6. High-resolution image analysis.

    Science.gov (United States)

    Preston, K

    1986-01-01

    In many departments of cytology, cytogenetics, hematology, and pathology, research projects using high-resolution computerized microscopy are now being mounted for computation of morphometric measurements on various structural components, as well as for determination of cellular DNA content. The majority of these measurements are made in a partially automated, computer-assisted mode, wherein there is strong interaction between the user and the computerized microscope. At the same time, full automation has been accomplished for both sample preparation and sample examination for clinical determination of the white blood cell differential count. At the time of writing, approximately 1,000 robot differential counting microscopes are in the field, analyzing images of human white blood cells, red blood cells, and platelets at the overall rate of about 100,000 slides per day. This mammoth through-put represents a major accomplishment in the application of machine vision to automated microscopy for hematology. In other areas of automated high-resolution microscopy, such as cytology and cytogenetics, no commercial instruments are available (although a few metaphase-finding machines are available and other new machines have been announced during the past year). This is a disappointing product, considering the nearly half century of research effort in these areas. This paper provides examples of the state of the art in automation of cell analysis for blood smears, cervical smears, and chromosome preparations. Also treated are new developments in multi-resolution automated microscopy, where images are now being generated and analyzed by a single machine over a range of 64:1 magnification and from 10,000 X 20,000 to 500 X 500 in total picture elements (pixels). Examples of images of human lymph node and liver tissue are presented. Semi-automated systems are not treated, although there is mention of recent research in the automation of tissue analysis.

  7. Single Image Super Resolution via Sparse Reconstruction

    NARCIS (Netherlands)

    Kruithof, M.C.; Eekeren, A.W.M. van; Dijk, J.; Schutte, K.

    2012-01-01

    High resolution sensors are required for recognition purposes. Low resolution sensors, however, are still widely used. Software can be used to increase the resolution of such sensors. One way of increasing the resolution of the images produced is using multi-frame super resolution algorithms. Limita

  8. Quantifying and containing the curse of high resolution coronal imaging

    Directory of Open Access Journals (Sweden)

    V. Delouille

    2008-10-01

    Full Text Available Future missions such as Solar Orbiter (SO, InterHelioprobe, or Solar Probe aim at approaching the Sun closer than ever before, with on board some high resolution imagers (HRI having a subsecond cadence and a pixel area of about (80 km2 at the Sun during perihelion. In order to guarantee their scientific success, it is necessary to evaluate if the photon counts available at these resolution and cadence will provide a sufficient signal-to-noise ratio (SNR.

    For example, if the inhomogeneities in the Quiet Sun emission prevail at higher resolution, one may hope to locally have more photon counts than in the case of a uniform source. It is relevant to quantify how inhomogeneous the quiet corona will be for a pixel pitch that is about 20 times smaller than in the case of SoHO/EIT, and 5 times smaller than TRACE.

    We perform a first step in this direction by analyzing and characterizing the spatial intermittency of Quiet Sun images thanks to a multifractal analysis. We identify the parameters that specify the scale-invariance behavior. This identification allows next to select a family of multifractal processes, namely the Compound Poisson Cascades, that can synthesize artificial images having some of the scale-invariance properties observed on the recorded images.

    The prevalence of self-similarity in Quiet Sun coronal images makes it relevant to study the ratio between the SNR present at SoHO/EIT images and in coarsened images. SoHO/EIT images thus play the role of "high resolution" images, whereas the "low-resolution" coarsened images are rebinned so as to simulate a smaller angular resolution and/or a larger distance to the Sun. For a fixed difference in angular resolution and in Spacecraft-Sun distance, we determine the proportion of pixels having a SNR preserved at high resolution given a particular increase in effective area. If scale-invariance continues to prevail at smaller scales, the conclusion reached

  9. CHARRON: Code for High Angular Resolution of Rotating Objects in Nature

    Science.gov (United States)

    Domiciano de Souza, A.; Zorec, J.; Vakili, F.

    2012-12-01

    Rotation is one of the fundamental physical parameters governing stellar physics and evolution. At the same time, spectrally resolved optical/IR long-baseline interferometry has proven to be an important observing tool to measure many physical effects linked to rotation, in particular, stellar flattening, gravity darkening, differential rotation. In order to interpret the high angular resolution observations from modern spectro-interferometers, such as VLTI/AMBER and VEGA/CHARA, we have developed an interferometry-oriented numerical model: CHARRON (Code for High Angular Resolution of Rotating Objects in Nature). We present here the characteristics of CHARRON, which is faster (≃q10-30 s per model) and thus more adapted to model-fitting than the first version of the code presented by Domiciano de Souza et al. (2002).

  10. Identification of sub-grains and low angle boundaries beyond the angular resolution of EBSD maps

    Energy Technology Data Exchange (ETDEWEB)

    Germain, L., E-mail: Lionel.germain@univ-lorraine.fr [Laboratoire d' Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (‘LabEx DAMAS’), Université de Lorraine (France); Kratsch, D. [Laboratoire d' Informatique Théorique et Appliquée (LITA), EA3079, Université de Lorraine, 57045 Metz Cedex 1 (France); Salib, M. [Laboratoire d' Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (‘LabEx DAMAS’), Université de Lorraine (France); Institut Jean Lamour (IJL), SI2M Dept., CNRS UMR 7198, Université de Lorraine, Parc de Saurupt, CS 50840, F-54011 Nancy Cedex (France); Gey, N. [Laboratoire d' Etude des Microstructures et de Mécanique des Matériaux (LEM3), UMR 7239, CNRS/Université de Lorraine, F-57045 Metz (France); Laboratory of Excellence on Design of Alloy Metals for low-mAss Structures (‘LabEx DAMAS’), Université de Lorraine (France)

    2014-12-15

    A new method called ALGrId (Anti-Leak GRain IDentification) is proposed for the detection of sub-grains beyond the relative angular resolution of Electron Backscatter Diffraction maps. It does not use any additional information such as Kikuchi Pattern Quality map nor need data filtering. It uses a modified Dijkstra algorithm which seeks the continuous set of boundaries having the highest average disorientation angle. - Highlights: • ALGrId is a new method to identify sub-grains and low angle boundaries in EBSD maps. • Unlike classical methods, ALGrId works even beyond the relative angular resolution. • If the orientation noise peaks at 0.7°, ALGrid detects 0.4°-boundaries correctly. • In the same example, the classical algorithm identifies 1.1°-boundaries only.

  11. Next Generation X-ray Optics: High Angular Resolution, Light Weight, and Low Production Cost

    Science.gov (United States)

    Zhang, William

    2014-08-01

    Every conceivable future x-ray astronomical mission would require x-ray optics. These optics must meet the three-fold requirements of angular resolution, effective area, and cost.In this poster we will present the rationale, technical approach, and status of an x-ray optics technology development program that has been underway at Goddard Space Flight Center and Marshall Space Flight Center.

  12. Angular Resolution of a Photoelectric Polarimeter in the Focus of an Optical System

    OpenAIRE

    Lazzarotto, Francesco; Fabiani, Sergio; Costa, Enrico; Muleri, Fabio; Soffitta, Paolo; Di Cosimo, Sergio; Di Persio, Giuseppe; Rubini, Alda; Bellazzini, Ronaldo; Brez, Alessandro; Spandre, Gloria; Cotroneo, Vincenzo; Moretti, Alberto; Pareschi, Giovanni; Tagliaferri, Giampiero

    2009-01-01

    The INFN and INAF Italian research institutes developed a space-borne X-Ray polarimetry experiment based on a X-Ray telescope, focussing the radiation on a Gas Pixel Detector (GPD). The instrument obtains the polarization angle of the absorbed photons from the direction of emission of the photoelectrons as visualized in the GPD. Here we will show how we compute the angular resolution of such an instrument.

  13. Frequency and Angular Resolution for Measuring, Presenting and Predicting Loudspeaker Polar Data

    DEFF Research Database (Denmark)

    Staffeldt, Henrik; Seidel, Felicity

    1996-01-01

    The spherical polar loudspeaker data available today are usually measured with such a coarse resolution that only rough estimates of the performance of sound systems can be predicted by applying these data. Complex, spherical polar data with higher angular and frequency resolutions than used today...... measurement principles and systems, in terms of specific levels of accuracy, are also discussed. The presented material consists of research the authors have done for the AES Standards Committee SC-04-03, working group on loudspeaker modeling and measurement, toward a goal set by that working group...

  14. Thin fused silica optics for a high angular resolution and large collecting area X Ray telescope after Chandra

    Science.gov (United States)

    Pareschi, Giovanni; Citterio, Oberto; Civitani, Marta M; Basso, Stefano; Campana, Sergio; Conconi, Paolo; Ghigo, Mauro; Mattaini, Enrico; Moretti, Alberto; Parodi, Giancarlo; Tagliaferri, Gianpiero

    2014-08-01

    The implementation of an X-ray mission with high imaging capabilities, similar to those achieved with Chandra (SMART-X project, led by CfA together with other US institutes. This project is based on adjustable segments of thin foil mirrors with piezo-electric actuators, aiming to achieve an effective area >2 m2 at 1 keV and an angular resolution better than 1 arcsec HEW. Another attractive technology to realize an X-ray telescope with similar characteristics is being developed at NASA/Goddard. In this case the mirrors are based on Si substrates that are super-polished and figured starting from a bulky Si ingot, from which they are properly cut. Here we propose an alternative method based on precise direct grinding, figuring and polishing of thin (a few mm) glass shells with innovative deterministic polishing methods. This is followed by a final correction via ion figuring to obtain the desired accuracy. For this purpose, a temporary stiffening structure is used to support the shell from the polishing operations up to its integration in the telescope supporting structure. This paper deals with the technological process under development, the results achieved so far and some mission scenarios based on this kind of optics, aiming to achieve an effective area more than 10 times larger than Chandra and an angular resolution of 1 arcsec HEW on axis and of a few arcsec off-axis across a large field of view (1o in diameter).

  15. Ultrahigh Resolution 3-Dimensional Imaging Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Southwest Sciences proposes to develop innovative instrumentation for the rapid, 3-dimensional imaging of biological tissues with cellular resolution. Our approach...

  16. Moderate Resolution Imaging Spectroradiometer (MODIS) - Aqua

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset represents multiple products archived at the multiple archive centers for the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard...

  17. Moderate Resolution Imaging Spectroradiometer (MODIS) - Terra

    Data.gov (United States)

    National Aeronautics and Space Administration — This dataset represents multiple products archived at the multiple archive centers for the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard...

  18. SMA Observations of Class 0 Protostars: A High-Angular Resolution Survey of Protostellar Binary Systems

    CERN Document Server

    Chen, Xuepeng; Zhang, Qizhou; Bourke, Tyler L; Launhardt, Ralf; Jorgensen, Jes K; Lee, Chin-Fee; Foster, Jonathan B; Dunham, Michael M; Pineda, Jaime E; Henning, Thomas

    2013-01-01

    We present high angular resolution 1.3 mm and 850 um dust continuum data obtained with the Submillimeter Array toward 33 Class 0 protostars in nearby clouds (distance < 500 pc), which represents so far the largest survey toward protostellar binary/multiple systems. The median angular resolution in the survey is 2.5 arcsec, while the median linear resolution is approximately 600 AU. Compact dust continuum emission is observed from all sources in the sample. Twenty-one sources in the sample show signatures of binarity/multiplicity, with separations ranging from 50 to 5000 AU. The numbers of singles, binaries, triples, and quadruples in the sample are 12, 14, 5, and 2, respectively. The derived multiplicity frequency (MF) and companion star fraction (CSF) for Class 0 protostars are 0.64+/-0.08 and 0.91+/-0.05, respectively, with no correction for completeness. The derived MF and CSF in this survey are approximately two times higher than the values found in the binary surveys toward Class I YSOs, and approxima...

  19. Vibration-dependent angular anisotropy in the photodetachment of O{sub 2}{sup -}, viewed with velocity-map imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, S T; Cavanagh, S J; Lewis, B R [Research School of Physics and Engineering, Australian National University, Canberra ACT 0200 (Australia); Gascooke, J R [School of Chemistry, Physics and Earth Sciences, Flinders University, SA 5001 (Australia); Mabbs, R [Department of Chemistry, Washington University, St Louis MO 63930-4899 (United States); Sanov, A, E-mail: Stephen.Gibson@anu.edu.a, E-mail: Steven.Cavanagh@anu.edu.a [Department of Chemistry, University of Arizona, Tucson AZ 85721-0041 (United States)

    2009-11-01

    The photodetachment spectrum of O{sub 2}{sup -} has been measured at a number of wavelengths using velocity-map imaging. The electron kinetic-energy resolution (< 5 meV) is sufficient to resolve the anion fine-structure splitting, vibrational and electronic structure. The electron angular distribution varies with the electron kinetic-energy, with a different behaviour for each vibronic band.

  20. High Resolution Image Reconstruction from Projection of Low Resolution Images DIffering in Subpixel Shifts

    Science.gov (United States)

    Mareboyana, Manohar; Le Moigne-Stewart, Jacqueline; Bennett, Jerome

    2016-01-01

    In this paper, we demonstrate a simple algorithm that projects low resolution (LR) images differing in subpixel shifts on a high resolution (HR) also called super resolution (SR) grid. The algorithm is very effective in accuracy as well as time efficiency. A number of spatial interpolation techniques using nearest neighbor, inverse-distance weighted averages, Radial Basis Functions (RBF) etc. used in projection yield comparable results. For best accuracy of reconstructing SR image by a factor of two requires four LR images differing in four independent subpixel shifts. The algorithm has two steps: i) registration of low resolution images and (ii) shifting the low resolution images to align with reference image and projecting them on high resolution grid based on the shifts of each low resolution image using different interpolation techniques. Experiments are conducted by simulating low resolution images by subpixel shifts and subsampling of original high resolution image and the reconstructing the high resolution images from the simulated low resolution images. The results of accuracy of reconstruction are compared by using mean squared error measure between original high resolution image and reconstructed image. The algorithm was tested on remote sensing images and found to outperform previously proposed techniques such as Iterative Back Projection algorithm (IBP), Maximum Likelihood (ML), and Maximum a posterior (MAP) algorithms. The algorithm is robust and is not overly sensitive to the registration inaccuracies.

  1. VizieR Online Data Catalog: High angular resolution spectroscopy of NGC 1277 (Walsh+, 2016)

    Science.gov (United States)

    Walsh, J. L.; van den Bosch, R. C. E.; Gebhardt, K.; Yildirim, A.; Richstone, D. O.; Gultekin, K.; Husemann, B.

    2016-03-01

    We obtained high angular resolution spectroscopy of NGC 1277 using the Near-infrared Integral Field Spectrometer (NIFS) with the ALTtitude conjugate Adaptive optics for the InfraRed system on the Gemini North telescope. The observations were taken as part of program GN-2011B-Q-27 over the course of four nights, spanning from 2012 October 30 to 2012 December 27. We observed NGC 1277 using 600s object-sky-object exposures with the H+K filter and K grating centered on 2.2μm. (1 data file).

  2. Effects of spatial resolution on image registration

    Science.gov (United States)

    Zhao, Can; Carass, Aaron; Jog, Amod; Prince, Jerry L.

    2016-03-01

    This paper presents a theoretical analysis of the effect of spatial resolution on image registration. Based on the assumption of additive Gaussian noise on the images, the mean and variance of the distribution of the sum of squared differences (SSD) were estimated. Using these estimates, we evaluate a distance between the SSD distributions of aligned images and non-aligned images. The experimental results show that by matching the resolutions of the moving and fixed images one can get a better image registration result. The results agree with our theoretical analysis of SSD, but also suggest that it may be valid for mutual information as well.

  3. Discrete time interval measurement system: fundamentals, resolution and errors in the measurement of angular vibrations

    International Nuclear Information System (INIS)

    The traditional method for measuring the velocity and the angular vibration in the shaft of rotating machines using incremental encoders is based on counting the pulses at given time intervals. This method is generically called the time interval measurement system (TIMS). A variant of this method that we have developed in this work consists of measuring the corresponding time of each pulse from the encoder and sampling the signal by means of an A/D converter as if it were an analog signal, that is to say, in discrete time. For this reason, we have denominated this method as the discrete time interval measurement system (DTIMS). This measurement system provides a substantial improvement in the precision and frequency resolution compared with the traditional method of counting pulses. In addition, this method permits modification of the width of some pulses in order to obtain a mark-phase on every lap. This paper explains the theoretical fundamentals of the DTIMS and its application for measuring the angular vibrations of rotating machines. It also displays the required relationship between the sampling rate of the signal, the number of pulses of the encoder and the rotating velocity in order to obtain the required resolution and to delimit the methodological errors in the measurement

  4. Atomic resolution images of graphite in air

    Energy Technology Data Exchange (ETDEWEB)

    Grigg, D.A.; Shedd, G.M.; Griffis, D.; Russell, P.E.

    1988-12-01

    One sample used for proof of operation for atomic resolution in STM is highly oriented pyrolytic graphite (HOPG). This sample has been imaged with many different STM`s obtaining similar results. Atomic resolution images of HOPG have now been obtained using an STM designed and built at the Precision Engineering Center. This paper discusses the theoretical predictions and experimental results obtained in imaging of HOPG.

  5. The role of dislocations in varied olivine deformation mechanisms investigated using high-angular resolution electron backscatter diffraction

    Science.gov (United States)

    Wallis, David; Hansen, Lars; Britton, Ben; Wilkinson, Angus

    2016-04-01

    Experimentally-derived flow laws can be used to predict the rheology of rocks deformed under natural conditions only if the same microphysical processes can be demonstrated to control the rate-limiting deformation mechanism in both cases. Olivine rheology may exert a principle control on the strength of the lithosphere, and therefore considerable research effort has been applied to assessing its rheology through experimental, geological, and geophysical approaches. Nonetheless, considerable uncertainty remains regarding the dominant deformation mechanisms in the upper mantle. This uncertainty arises in large part due to our limited understanding of the fundamental deformation processes associated with each mechanism. Future improvements to microphysical models of distinct deformation mechanisms require new insight into the contributions those fundamental processes to the macroscopic behaviour. The dynamics of dislocations is central to modelling viscous deformation of olivine, but characterisation techniques capable of constraining dislocation types, densities, and distributions over the critical grain to polycrystal length-scales have been lacking. High angular resolution electron backscatter diffraction (HR-EBSD), developed and increasingly applied in the material sciences, offers an approach capable of such analyses. HR-EBSD utilises diffraction pattern image cross-correlation to achieve dramatically improved angular resolution (~0.01°) of lattice orientation gradients compared to conventional Hough-based EBSD (~0.5°). This angular resolution allows very low densities (≥ 10^11 m^-2) of geometrically necessary dislocations (GND) to be resolved, facilitating analysis of a wide range of dislocation microstructures. We have developed the application of HR-EBSD to olivine and applied it to samples deformed both experimentally and naturally in grain-size sensitive and grain-size insensitive regimes. The results quantitatively highlight variations in the types and

  6. Polarization imaging with enhanced spatial resolution

    Science.gov (United States)

    Peinado, A.; Lizana, A.; Iemmi, C.; Campos, J.

    2015-03-01

    We present the design and the experimental implementation of a new imaging set-up, based on Liquid Crystal technology, able to obtain super-resolved polarimetric images of polarimetric samples when the resolution is detector limited. The proposed set-up is a combination of two modules. One of them is an imaging Stokes polarimeter, based on Ferroelectric Liquid Crystal cells, which is used to analyze the polarization spatial distribution of an incident beam. The other module is used to obtain high resolved intensity images of the sample in an optical system whose resolution is mainly limited by the CCD pixel geometry. It contains a calibrated Parallel Aligned Liquid Crystal on Silicon display employed to introduce controlled linear phases. As a result, a set of different low resolved intensity images with sub-pixel displacements are captured by the CCD. By properly combining these images and after applying a deconvolution process, a super-resolved intensity image of the object is obtained. Finally, the combination of the two different optical modules permits to employ super-resolved images during the polarimetric data reduction calculation, leading to a final polarization image with enhanced spatial resolution. The proposed optical set-up performance is implemented and experimentally validated by providing super-resolved images of an amplitude resolution test and a birefringent resolution test. A significant improvement in the spatial resolution (by a factor of 1.4) of the obtained polarimetric images, in comparison with the images obtained with the regular imaging system, is clearly observed when applying our proposed technique.

  7. Direction and movement angular velocity determining of cloudiness with panoramic images of the sky

    Science.gov (United States)

    Galileiskii, Viktor P.; Elizarov, Alexey I.; Kokarev, Dmitrii V.; Morozov, Aleksandr M.

    2014-11-01

    This article gives a short overview to method of direction determining and visible angular velocity of movement determining of cloudiness based on set of panoramic images of cloudy sky, obtained by "Fisheye" wide-angle lens.

  8. Large Quantum imaging of nonlocal spatial correlations induced by orbital angular momentum

    CERN Document Server

    Altman, A; Corndorf, E; Kumar, P; Barbosa, G A; Altman, Adam R.; K\\"{o}pr\\"{u}l\\"{u}, Kahraman G.; Corndorf, Eric; Kumar, Prem; Barbosa, Geraldo A.

    2004-01-01

    Through scanned coincidence counting, we probe the quantum image produced by parametric down conversion with a pump beam carrying orbital angular momentum. Nonlocal spatial correlations are manifested through splitting of the coincidence spot into two.

  9. Satellite Angular Velocity Estimation Based on Star Images and Optical Flow Techniques

    OpenAIRE

    Giancarmine Fasano; Giancarlo Rufino; Domenico Accardo; Michele Grassi

    2013-01-01

    An optical flow-based technique is proposed to estimate spacecraft angular velocity based on sequences of star-field images. It does not require star identification and can be thus used to also deliver angular rate information when attitude determination is not possible, as during platform de tumbling or slewing. Region-based optical flow calculation is carried out on successive star images preprocessed to remove background. Sensor calibration parameters, Poisson equation, and a least-squares...

  10. The Evershed effect observed with 0.2 arsec angular resolution

    CERN Document Server

    Almeida, J S; Bonet, J A; Cerdena, I D

    2006-01-01

    We present an analysis of the Evershed effect observed with a resolution of 0.2 arcsec. Using the new Swedish 1-m Solar Telescope and its Littrow spectrograph, we scan a significant part of a sunspot penumbra. Spectra of the non-magnetic line Fe I 7090.4 A allows us to measure Doppler shifts without magnetic contamination. The observed line profiles are asymmetric. The Doppler shift depends on the part of the line used for measuring, indicating that the velocity structure of penumbrae remains unresolved even with our angular resolution. The observed line profiles are properly reproduced if two components with velocities between zero and several km/s co-exist in the resolution elements. Using Doppler shifts at fixed line depths, we find a local correlation between upflows and bright structures, and downflows and dark structures. This association is not specific of the outer penumbra but it also occurs in the inner penumbra. The existence of such correlation was originally reported by Beckers & Schroter (19...

  11. Translation, rotation, and scale invariant image registration technique using angular and radial difference functions

    Institute of Scientific and Technical Information of China (English)

    Li Li; Qingshuang Zeng; Fanfeng Meng

    2008-01-01

    An algorithm is proposed for registering images related by translation, rotation, and scale based on angular and radial difference fimctions. In frequency domain, the spatial translation parameters are computed via phase correlation method. The magnitudes of images are represented in log-polar grid, and the angular and radial difference functions are given and applied to measure shifts in both angular and radial dimensions for rotation and scale estimation. Experimental results show that this method achieves the same accurate level as classic fast Fourier transform (FFT) based method with invariance to illumination change and lower computation costs.

  12. High-Angular-Resolution and High-Sensitivity Science Enabled by Beamformed ALMA

    CERN Document Server

    Fish, Vincent; Anderson, James; Asada, Keiichi; Baudry, Alain; Broderick, Avery; Carilli, Chris; Colomer, Francisco; Conway, John; Dexter, Jason; Doeleman, Sheperd; Eatough, Ralph; Falcke, Heino; Frey, Sándor; Gabányi, Krisztina; Gálvan-Madrid, Roberto; Gammie, Charles; Giroletti, Marcello; Goddi, Ciriaco; Gómez, Jose L; Hada, Kazuhiro; Hecht, Michael; Honma, Mareki; Humphreys, Elizabeth; Impellizzeri, Violette; Johannsen, Tim; Jorstad, Svetlana; Kino, Motoki; Körding, Elmar; Kramer, Michael; Krichbaum, Thomas; Kudryavtseva, Nadia; Laing, Robert; Lazio, Joseph; Loeb, Abraham; Lu, Ru-Sen; Maccarone, Thomas; Marscher, Alan; Mart'ı-Vidal, Iván; Martins, Carlos; Matthews, Lynn; Menten, Karl; Miller, Jon; Miller-Jones, James; Mirabel, Félix; Muller, Sebastien; Nagai, Hiroshi; Nagar, Neil; Nakamura, Masanori; Paragi, Zsolt; Pradel, Nicolas; Psaltis, Dimitrios; Ransom, Scott; Rodr'\\iguez, Luis; Rottmann, Helge; Rushton, Anthony; Shen, Zhi-Qiang; Smith, David; Stappers, Benjamin; Takahashi, Rohta; Tarchi, Andrea; Tilanus, Remo; Verbiest, Joris; Vlemmings, Wouter; Walker, R Craig; Wardle, John; Wiik, Kaj; Zackrisson, Erik; Zensus, J Anton

    2013-01-01

    An international consortium is presently constructing a beamformer for the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile that will be available as a facility instrument. The beamformer will aggregate the entire collecting area of the array into a single, very large aperture. The extraordinary sensitivity of phased ALMA, combined with the extremely fine angular resolution available on baselines to the Northern Hemisphere, will enable transformational new very long baseline interferometry (VLBI) observations in Bands 6 and 7 (1.3 and 0.8 mm) and provide substantial improvements to existing VLBI arrays in Bands 1 and 3 (7 and 3 mm). The ALMA beamformer will have impact on a variety of scientific topics, including accretion and outflow processes around black holes in active galactic nuclei (AGN), tests of general relativity near black holes, jet launch and collimation from AGN and microquasars, pulsar and magnetar emission processes, the chemical history of the universe and the evolution of fundame...

  13. High Angular Resolution Observations of Four Candidate BLAST High-Mass Starless Cores

    CERN Document Server

    Olmi, Luca; Chapin, Edward L; Gibb, Andrew; Hofner, Peter; Martin, Peter G; Poventud, Carlos M

    2010-01-01

    We discuss high-angular resolution observations of ammonia toward four candidate high-mass starless cores (HMSCs). The cores were identified by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) during its 2005 survey of the Vulpecula region where 60 compact sources were detected simultaneously at 250, 350, and 500 micron. Four of these cores, with no IRAS-PSC or MSX counterparts, were observed with the NRAO Very Large Array (VLA) in the NH3(1,1) and (2,2) spectral lines. Our observations indicate that the four cores are cold (Tk <~ 14K) and show a filamentary and/or clumpy structure. They also show a significant velocity substructure within ~1km/s. The four BLAST cores appear to be colder and more quiescent than other previously observed HMSC candidates, suggesting an earlier stage of evolution.

  14. Analysis of angular reading distortions of photographic images Análise das distorções em leituras angulares de imagens fotográficas

    Directory of Open Access Journals (Sweden)

    Gabriela F. Codarin

    2012-08-01

    Full Text Available BACKGROUND: Although photogrammetry is a widespread technique in the health field, despite of the methodological efforts distortions in the angular readings of the images are common. OBJECTIVE: To measure the error of angular measurements in photo images with different digital resolutions in an object with pre-determined angles. METHODS: We used a rubber ball with 52 cm in circumference. The object was previously marked with angles of 10°, 30°, 60° and 90° degrees. The photographic records were performed with the focal axis of the camera perpendicular and three meters away from the object, without the use of optical zoom and a resolution of 3, 5 and 10 Megapixels (Mp. All photographic records were stored and a previously trained experimenter using the computer program ImageJ analyzed the angular values of each photo. The measurements were performed twice within a fifteen-days interval. Subsequently, we calculated the accuracy, relative error and error in degrees values, precision and the Intraclass Correlation Coefficient (ICC. RESULTS: When analyzing the angle of 10°, the average accuracy of measurements was higher for those records of 3 Mp resolution compared to 5 and 10 Mp resolutions. The ICC was considered excellent for all resolutions. With regards to the analyzed angles in photographic records, it was possible to verify that the 90-degree angle photographs were more accurate, had lower relative error and error in degrees, and were more precise, regardless of image resolution. CONCLUSION: The photographs records that were taken with a 3 Mp resolution provided great accuracy and precision measurements and lower errors values, suggesting to be the proper resolution to generate image of angles of 10º and 30º.CONTEXTUALIZAÇÃO: A biofotogrametria é uma técnica difundida na área da saúde e, apesar dos cuidados metodológicos, há distorções nas leituras angulares das imagens fotográficas. OBJETIVO: Mensurar o erro das medidas

  15. Semiconductor crystal high resolution imager

    Science.gov (United States)

    Levin, Craig S. (Inventor); Matteson, James (Inventor)

    2011-01-01

    A radiation imaging device (10). The radiation image device (10) comprises a subject radiation station (12) producing photon emissions (14), and at least one semiconductor crystal detector (16) arranged in an edge-on orientation with respect to the emitted photons (14) to directly receive the emitted photons (14) and produce a signal. The semiconductor crystal detector (16) comprises at least one anode and at least one cathode that produces the signal in response to the emitted photons (14).

  16. ONE-DIMENSIONAL LIGHT BEAM WIDENING USING PRISMS FOR INCREASE OF SPECTROMETER SPECTRAL RESOLUTION AND ANGULAR DISPERSION

    Directory of Open Access Journals (Sweden)

    I. M. Gulis

    2016-01-01

    Full Text Available The increase of angular dispersion and slit resolution limit of grating spectrometers by means of variation of grating parameters is limited by its period and allowable order of diffraction. The special solutions (echelle, holographic, immersion gratings are acceptable in a limited parameter range and are technologically complex in fabrication, thus hardly applicable to instruments of mass production. We propose to decrease slit resolution limit by one-dimensional beam widening in dispersion plane by means of passing it through oblique prism before incidence onto diffraction grating. The increase of angular dispersion can be achieved by narrowing of dispersed beams after grating while passing through other oblique prism. We prove that slit resolution limit in such a system changes approximately as multiplied by angular magnification of the first prism (that is less than 1 times. Also angular dispersion changed approximately as multiplied by angular magnification of the second prism. The Fresnel reflection from the faces of prisms is analyzed. Accounting for that factor gives the increase of resolution about 1,4–1,6 times without loss of light (and can be 2 and more times while using anti-reflective coating. The proposed method is different from the similar ones first of all by its simplicity because it uses simple optical elements – plane reflective grating and thin prisms. It can be applied to amend the analytical characteristics of dispersive spectrometers, first of all the small-sized ones. 

  17. SMA OBSERVATIONS OF CLASS 0 PROTOSTARS: A HIGH ANGULAR RESOLUTION SURVEY OF PROTOSTELLAR BINARY SYSTEMS

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xuepeng [Purple Mountain Observatory, Chinese Academy of Sciences, 2 West Beijing Road, Nanjing 210008 (China); Arce, Hector G.; Dunham, Michael M. [Department of Astronomy, Yale University, Box 208101, New Haven, CT 06520-8101 (United States); Zhang Qizhou; Bourke, Tyler L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Launhardt, Ralf; Henning, Thomas [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Jorgensen, Jes K. [Niels Bohr Institute and Centre for Star and Planet Formation, Copenhagen University, Juliane Maries Vej 30, DK-2100 Copenhagen O (Denmark); Lee, Chin-Fei [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 106, Taiwan (China); Foster, Jonathan B. [Institute for Astrophysical Research, Boston University, Boston, MA 02215 (United States); Pineda, Jaime E., E-mail: xpchen@pmo.ac.cn, E-mail: xuepeng.chen@yale.edu [ESO, Karl Schwarzschild Str. 2, D-85748 Garching bei Munchen (Germany)

    2013-05-10

    We present high angular resolution 1.3 mm and 850 {mu}m dust continuum data obtained with the Submillimeter Array toward 33 Class 0 protostars in nearby clouds (distance < 500 pc), which represents so far the largest survey toward protostellar binary/multiple systems. The median angular resolution in the survey is 2.''5, while the median linear resolution is approximately 600 AU. Compact dust continuum emission is observed from all sources in the sample. Twenty-one sources in the sample show signatures of binarity/multiplicity, with separations ranging from 50 AU to 5000 AU. The numbers of singles, binaries, triples, and quadruples in the sample are 12, 14, 5, and 2, respectively. The derived multiplicity frequency (MF) and companion star fraction (CSF) for Class 0 protostars are 0.64 {+-} 0.08 and 0.91 {+-} 0.05, respectively, with no correction for completeness. The derived MF and CSF in this survey are approximately two times higher than the values found in the binary surveys toward Class I young stellar objects, and approximately three (for MF) and four (for CSF) times larger than the values found among main-sequence stars, with a similar range of separations. Furthermore, the observed fraction of high-order multiple systems to binary systems in Class 0 protostars (0.50 {+-} 0.09) is also larger than the fractions found in Class I young stellar objects (0.31 {+-} 0.07) and main-sequence stars ({<=}0.2). These results suggest that binary properties evolve as protostars evolve, as predicted by numerical simulations. The distribution of separations for Class 0 protostellar binary/multiple systems shows a general trend in which CSF increases with decreasing companion separation. We find that 67% {+-} 8% of the protobinary systems have circumstellar mass ratios below 0.5, implying that unequal-mass systems are preferred in the process of binary star formation. We suggest an empirical sequential fragmentation picture for binary star formation, based on this

  18. Hard X-ray photoemission with angular resolution and standing-wave excitation

    Energy Technology Data Exchange (ETDEWEB)

    Fadley, Charles S., E-mail: fadley@physics.ucdavis.edu [Department of Physics, University of California Davis, Davis, CA 95616 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2013-10-15

    Highlights: •Hard X-ray photoemission with angle resolution and standing-waves is discussed. •Hard X-ray angle-resolved photoemission yields k{sup →}-resolved bulk electronic structure. •Hard X-ray photoelectron diffraction provides element-specific atomic structure. •Multilayer standing-wave measurements add depth-resolved composition. •Standing-wave excitation also yields element-specific densities of states. -- Abstract: Several aspects of hard X-ray photoemission that make use of angular resolution and/or standing-wave excitation are discussed. These include hard X-ray angle-resolved photoemission (HARPES) from valence levels, which has the capability of determining bulk electronic structure in a momentum-resolved way; hard X-ray photoelectron diffraction (HXPD), which shows promise for studying element-specific bulk atomic structure, including dopant site occupations; and standing wave studies of the composition and chemical states of buried layers and interfaces. Beyond this, standing wave photoemission can be used to derive element-specific densities of states. Some recent examples relevant to all of these aspects are discussed.

  19. The GAMMA-400 gamma-ray telescope characteristics. Angular resolution and electrons/protons separation

    CERN Document Server

    Leonov, A A; Bonvicini, V; Topchiev, N P; Adriani, O; Aptekar, R L; Arkhangelskaja, I V; Arkhangelskiy, A I; Bergstrom, L; Berti, E; Bigongiari, G; Bobkov, S G; Boezio, M; Bogomolov, E A; Bonechi, S; Bongi, M; Bottai, S; Boyarchuk, K A; Castellini, G; Cattaneo, P W; Cumani, P; Dedenko, G L; De Donato, C; Dogiel, V A; Gorbunov, M S; Gusakov, Yu V; Hnatyk, B I; Kadilin, V V; Kaplin, V A; Kaplun, A A; Kheymits, M D; Korepanov, V E; Larsson, J; Loginov, V A; Longo, F; Maestro, P; Marrocchesi, P S; Mikhailov, V V; Mocchiutti, E; Moiseev, A A; Mori, N; Moskalenko, I V; Naumov, P Yu; Papini, P; Pearce, M; Picozza, P; Popov, A V; Rappoldi, A; Ricciarini, S; Runtso, M F; Ryde, F; Serdin, O V; Sparvoli, R; Spillantini, P; Suchkov, S I; Tavani, M; Taraskin, A A; Tiberio, A; Tyurin, E M; Ulanov, M V; Vacchi, A; Vannuccini, E; Vasilyev, G I; Yurkin, Yu T; Zampa, N; Zirakashvili, V N; Zverev, V G

    2014-01-01

    The measurements of gamma-ray fluxes and cosmic-ray electrons and positrons in the energy range from 100 MeV to several TeV, which will be implemented by the specially designed GAMMA-400 gamma-ray telescope, concern with the following broad range of science topics. Searching for signatures of dark matter, surveying the celestial sphere in order to study gamma-ray point and extended sources, measuring the energy spectra of Galactic and extragalactic diffuse gamma-ray emission, studying gamma-ray bursts and gamma-ray emission from the Sun, as well as high precision measuring spectra of high-energy electrons and positrons, protons and nuclei up to the knee. To clarify these scientific problems with the new experimental data the GAMMA-400 gamma-ray telescope possesses unique physical characteristics comparing with previous and present experiments. For gamma-ray energies more than 100 GeV GAMMA-400 provides the energy resolution of ~1% and angular resolution better than 0.02 deg. The methods developed to reconstru...

  20. Coexistence of Near-Field and Far-Field Sources: the Angular Resolution Limit

    International Nuclear Information System (INIS)

    Passive source localization is a well known inverse problem in which we convert the observed measurements into information about the direction of arrivals. In this paper we focus on the optimal resolution of such problem. More precisely, we propose in this contribution to derive and analyze the Angular Resolution Limit (ARL) for the scenario of mixed Near-Field (NF) and Far-Field (FF) Sources. This scenario is relevant to some realistic situations. We base our analysis on the Smith's equation which involves the Cramér-Rao Bound (CRB). This equation provides the theoretical ARL which is independent of a specific estimator. Our methodology is the following: first, we derive a closed-form expression of the CRB for the considered problem. Using these expressions, we can rewrite the Smith's equation as a 4-th order polynomial by assuming a small separation of the sources. Finally, we derive in closed-form the analytic ARL under or not the assumption of low noise variance. The obtained expression is compact and can provide useful qualitative informations on the behavior of the ARL

  1. Overview of techniques used for image resolution enhancement

    Directory of Open Access Journals (Sweden)

    Mayuri D Patil

    2012-07-01

    Full Text Available Image resolution enhancement is one of the first steps in image processing. Image resolution enhancement is the process of manipulating an image so that resultant image is more suitable than the original one for specific application. Image enhancement can be done in various domains. For image resolution enhancement there are many methods, out of which image interpolation scheme is one of themost effective method. However, resolution is vital aspect of any image. Good quality image i.e. high resolution image produces better result in image processing applications. An interpolation is thetechnique to increase the resolution of the image by selecting new pixel from surrounding one. Image interpolation in complex wavelet transform is produces better results for any imaging application.DTCWT technique is used to improve the resolution of any satellite image. The paper focuses on the different techniques that are used to increase resolution of the images and their comparative results.

  2. Does resolution really increase image quality?

    Science.gov (United States)

    Tisse, Christel-Loïc; Guichard, Frédéric; Cao, Frédéric

    2008-02-01

    A general trend in the CMOS image sensor market is for increasing resolution (by having a larger number of pixels) while keeping a small form factor by shrinking photosite size. This article discusses the impact of this trend on some of the main attributes of image quality. The first example is image sharpness. A smaller pitch theoretically allows a larger limiting resolution which is derived from the Modulation Transfer Function (MTF). But recent sensor technologies (1.75μm, and soon 1.45μm) with typical aperture f/2.8 are clearly reaching the size of the diffraction blur spot. A second example is the impact on pixel light sensitivity and image sensor noise. For photonic noise, the Signal-to-Noise-Ratio (SNR) is typically a decreasing function of the resolution. To evaluate whether shrinking pixel size could be beneficial to the image quality, the tradeoff between spatial resolution and light sensitivity is examined by comparing the image information capacity of sensors with varying pixel size. A theoretical analysis that takes into consideration measured and predictive models of pixel performance degradation and improvement associated with CMOS imager technology scaling, is presented. This analysis is completed by a benchmarking of recent commercial sensors with different pixel technologies.

  3. SPI: A high resolution imaging spectrometer for INTEGRAL

    International Nuclear Information System (INIS)

    SPI (Spectrometer for INTEGRAL) is a high spectral resolution gamma-ray telescope using cooled germanium detectors that will be flown on board the INTEGRAL mission in 2001. It consists of an array of 19 closely-packed germanium detectors surrounded by an active bismuth germanate (BGO) anti-coincidence shield. The instrument operates over the energy range 20 keV to 8 MeV with an energy resolution of 1-5 keV. A tungsten coded-aperture mask located 1.7 m from the detector array provides imaging over a 15 deg. fully-coded field-of-view with an angular resolution of ∼3 deg. The point source narrow-line sensitivity is estimated to be 3-7x10-6 ph cm-2 s-1 over most of the range of the instrument (E>200 keV) for a 106 s observation. With its combination of high sensitivity, high spectral resolution and imaging, SPI will improve significantly over the performance of previous instruments such as HEAO-3, OSSE, and Comptel. It can be expected to take a major step forward in experimental studies in nuclear astrophysics. The SPI instrument is being developed under the auspices of the European Space Agency by a large international team of scientists and engineers in both Europe and the United States

  4. Importance of energy and angular resolutions in top-hat electrostatic analysers for solar wind proton measurements

    Science.gov (United States)

    De Marco, R.; Marcucci, M. F.; Bruno, R.; D'Amicis, R.; Servidio, S.; Valentini, F.; Lavraud, B.; Louarn, P.; Salatti, M.

    2016-08-01

    We use a numerical code which reproduces the angular/energy response of a typical top-hat electrostatic analyser starting from solar wind proton velocity distribution functions (VDFs) generated by numerical simulations. The simulations are based on the Hybrid Vlasov-Maxwell numerical algorithm which integrates the Vlasov equation for the ion distribution function, while the electrons are treated as a fluid. A virtual satellite launched through the simulation box measures the particle VDFs. Such VDFs are moved from the simulation Cartesian grid to energy-angular coordinates to mimic the response of a real sensor in the solar wind. Different energy-angular resolutions of the analyser are investigated in order to understand the influence of the phase-space resolution in existing and upcoming space missions, with regards to determining the key parameters of plasma dynamics.

  5. Stability of dislocation structures in copper towards stress relaxation investigated by high angular resolution 3D X-ray diffraction

    DEFF Research Database (Denmark)

    Jakobsen, Bo; Poulsen, Henning Friis; Lienert, Ulrich;

    2009-01-01

    A 300 µm thick tensile specimen of OFHC copper is subjected to a tensile loading sequence and deformed to a maximal strain of 3.11%. Using the novel three-dimensional X-ray diffraction method High angular resolution 3DXRD', the evolution of the microstructure within a deeply embedded grain is cha...

  6. Resolution of electro-holographic image

    Science.gov (United States)

    Son, Jung-Young; Chernyshov, Oleksii; Lee, Hyoung; Lee, Beom-Ryeol; Park, Min-Chul

    2016-06-01

    The resolution of the reconstructed image from a hologram displayed on a DMD is measured with the light field images along the propagation direction of the reconstructed image. The light field images reveal that a point and line image suffers a strong astigmatism but the line focusing distance differences for lines with different directions. This will be astigmatism too. The focusing distance of the reconstructed image is shorter than that of the object. The two lines in transverse direction are resolved when the gap between them is around 16 pixels of the DMD's in use. However, the depth direction is difficult to estimate due to the depth of focus of each line. Due to the astigmatism, the reconstructed image of a square appears as a rectangle or a rhombus.

  7. Southern Massive Stars at High Angular Resolution: Observational Campaign and Companion Detection

    CERN Document Server

    Sana, H; Lacour, S; Berger, J -P; Duvert, G; Gauchet, L; Norris, B; Olofsson, J; Pickel, D; Zins, G; Absil, O; de Koter, A; Kratter, K; Schnurr, O; Zinnecker, H

    2014-01-01

    Multiplicity is one of the most fundamental observable properties of massive O-type stars and offers a promising way to discriminate between massive star formation theories. Nevertheless, companions at separations between 1 and 100 mas remain mostly unknown due to intrinsic observational limitations. [...] The Southern MAssive Stars at High angular resolution survey (SMASH+) was designed to fill this gap by providing the first systematic interferometric survey of Galactic massive stars. We observed 117 O-type stars with VLTI/PIONIER and 162 O-type stars with NACO/SAM, respectively probing the separation ranges 1-45 and 30-250mas and brightness contrasts of Delta H < 4 and Delta H < 5. Taking advantage of NACO's field-of-view, we further uniformly searched for visual companions in an 8''-radius down to Delta H = 8. This paper describes the observations and data analysis, reports the discovery of almost 200 new companions in the separation range from 1mas to 8'' and presents the catalog of detections, inc...

  8. Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center

    CERN Document Server

    Richichi, A; Mason, E; Stegmaier, J; Chandrasekhar, T

    2008-01-01

    For the first time, the lunar occultation technique has been employed on a very large telescope in the near-IR with the aim of achieving systematically milliarcsecond resolution on stellar sources. We have demonstrated the burst mode of the ISAAC instrument, using a fast read-out on a small area of the detector to record many tens of seconds of data at a time on fields of few squared arcsec. We have used the opportunity to record a large number of LO events during a passage of the Moon close to the Galactic Center in March 2006. We have developed a data pipeline for the treatment of LO data, including the automated estimation of the main data analysis parameters using a wavelet-based method, and the preliminary fitting and plotting of all light curves. We recorded 51 LO events over about four hours. Of these, 30 resulted of sufficient quality to enable a detailed fitting. We detected two binaries with subarcsec projected separation and three stars with a marginally resolved angular diameter of about 2 mas. Tw...

  9. On solving the orientation gradient dependency of high angular resolution EBSD

    Energy Technology Data Exchange (ETDEWEB)

    Maurice, Claire, E-mail: maurice@emse.fr [Ecole des Mines de Saint-Etienne, UMR CNRS 5146 LCG, 158 cours Fauriel, F-42023 Saint-Etienne (France); Driver, Julian H. [Ecole des Mines de Saint-Etienne, UMR CNRS 5146 LCG, 158 cours Fauriel, F-42023 Saint-Etienne (France); Fortunier, Roland [Universite de Lyon, ENISE, UMR CNRS 5513 LTDS, 58 rue Jean Parot, F-42100 Saint-Etienne (France)

    2012-02-15

    Current high angular resolution electron backscatter diffraction (HR-EBSD) methods are successful at measuring pure elastic strains but have difficulties with plastically deformed metals containing orientation gradients. The strong influences of these rotations have been systematically studied using simulated patterns based on the many-beam dynamic theory of EBSP formation; a rotation of only 1 Degree-Sign can lead to apparent elastic strains of several hundred microstrains. A new method is proposed to correct for orientation gradient effects using a two-step procedure integrating finite strain theory: (i) reference pattern rotation and (ii) cross-correlation; it reduces the strain errors on the simulated patterns to tens of microstrains. An application to plastically deformed ferritic steel to generates elastic strain maps with significantly reduced values of both strains and residual errors in regions of rotations exceeding 1 Degree-Sign . -- Highlights: Black-Right-Pointing-Pointer Many-beam theory simulations show that HR-EBSD is sensitive to orientation gradients. Black-Right-Pointing-Pointer Finite strain theory and rotation processing the reference EBSP solves the problem. Black-Right-Pointing-Pointer New method succesfully applied to plastically strained IF steel.

  10. Sub-Airy disk angular resolution with high dynamic range in the near-infrared

    Directory of Open Access Journals (Sweden)

    Richichi A.

    2011-07-01

    Full Text Available Lunar occultations (LO are a simple and effective high angular resolution method, with minimum requirements in instrumentation and telescope time. They rely on the analysis of the diffraction fringes created by the lunar limb. The diffraction phenomen occurs in space, and as a result LO are highly insensitive to most of the degrading effects that limit the performance of traditional single telescope and long-baseline interferometric techniques used for direct detection of faint, close companions to bright stars. We present very recent results obtained with the technique of lunar occultations in the near-IR, showing the detection of companions with very high dynamic range as close as few milliarcseconds to the primary star. We discuss the potential improvements that could be made, to increase further the current performance. Of course, LO are fixed-time events applicable only to sources which happen to lie on the Moon’s apparent orbit. However, with the continuously increasing numbers of potential exoplanets and brown dwarfs beign discovered, the frequency of such events is not negligible. I will list some of the most favorable potential LO in the near future, to be observed from major observatories.

  11. Nuclear magnetic resonance imaging at microscopic resolution

    Science.gov (United States)

    Johnson, G. Allan; Thompson, Morrow B.; Gewalt, Sally L.; Hayes, Cecil E.

    Resolution limits in NMR imaging are imposed by bandwidth considerations, available magnetic gradients for spatial encoding, and signal to noise. This work reports modification of a clinical NMR imaging device with picture elements of 500 × 500 × 5000 μm to yield picture elements of 50 × 50 × 1000 μm. Resolution has been increased by using smaller gradient coils permitting gradient fields >0.4 mT/cm. Significant improvements in signal to noise are achieved with smaller rf coils, close attention to choice of bandwidth, and signal averaging. These improvements permit visualization of anatomical structures in the rat brain with an effective diameter of 1 cm with the same definition as is seen in human imaging. The techniques and instrumentation should open a number of basic sciences such as embryology, plant sciences, and teratology to the potentials of NMR imaging.

  12. Pyramidal fractal dimension for high resolution images

    Science.gov (United States)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024 ×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images.

  13. Pyramidal fractal dimension for high resolution images.

    Science.gov (United States)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

    Fractal analysis (FA) should be able to yield reliable and fast results for high-resolution digital images to be applicable in fields that require immediate outcomes. Triggered by an efficient implementation of FA for binary images, we present three new approaches for fractal dimension (D) estimation of images that utilize image pyramids, namely, the pyramid triangular prism, the pyramid gradient, and the pyramid differences method (PTPM, PGM, PDM). We evaluated the performance of the three new and five standard techniques when applied to images with sizes up to 8192 × 8192 pixels. By using artificial fractal images created by three different generator models as ground truth, we determined the scale ranges with minimum deviations between estimation and theory. All pyramidal methods (PM) resulted in reasonable D values for images of all generator models. Especially, for images with sizes ≥1024×1024 pixels, the PMs are superior to the investigated standard approaches in terms of accuracy and computation time. A measure for the possibility to differentiate images with different intrinsic D values did show not only that the PMs are well suited for all investigated image sizes, and preferable to standard methods especially for larger images, but also that results of standard D estimation techniques are strongly influenced by the image size. Fastest results were obtained with the PDM and PGM, followed by the PTPM. In terms of absolute D values best performing standard methods were magnitudes slower than the PMs. Concluding, the new PMs yield high quality results in short computation times and are therefore eligible methods for fast FA of high-resolution images. PMID:27475069

  14. MULTI-RESOLUTION SEAMLESS IMAGE DATABASE

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper presents the basic concepts and principles,data structure and high efficient spatial index for multi-resolution image database.The database is characterized by arrangement of multi-resource image data and seamless mosaic,distribution-based storage and management,integration with other spatial database software such as GeoStar and GeoGrid developed by Wuhan Technical University of Surveying and Mapping.

  15. Thin fused silica optics for a few arcsec angular resolution and large collecting area x-ray telescope

    Science.gov (United States)

    Citterio, O.; Civitani, M. M.; Pareschi, G.; Basso, S.; Campana, S.; Conconi, P.; Ghigo, M.; Mattaini, E.; Moretti, A.; Parodi, G.; Tagliaferri, G.

    2013-09-01

    The implementation of a X-ray mission with high imaging capabilities, similar to those achieved with Chandra (SMART-X project, led by CfA and involving several other US Institutes. This project is based on adjustable segments of thin foil mirrors with piezo-electric actuators, aiming to achieve an effective area mirrors are based on Si substrates that are super-polished and figured starting from a bulky Si ingot, from which they are properly cut. Here we propose an alternative method based on precise direct grinding, figuring and polishing of thin (a few mm) glass shells with innovative deterministic polishing methods. This is followed by a final correction via ion figuring to obtain the desired accuracy in order to achieve the 1 arc sec HEW requirement. For this purpose, a temporary stiffening structure is used to support the shell from the polishing operations up to its integration in the telescope supporting structure. We will present the technological process under development, the results achieved so far and some mission scenarios based on this kind of optics, aiming to achieve an effective area more than 10 times larger than Chandra and an angular resolution of 1 arcsec HEW on axis and of a few arcsec off-axis across a large field of view (1 deg in diameter).

  16. Satellite angular velocity estimation based on star images and optical flow techniques.

    Science.gov (United States)

    Fasano, Giancarmine; Rufino, Giancarlo; Accardo, Domenico; Grassi, Michele

    2013-01-01

    An optical flow-based technique is proposed to estimate spacecraft angular velocity based on sequences of star-field images. It does not require star identification and can be thus used to also deliver angular rate information when attitude determination is not possible, as during platform de tumbling or slewing. Region-based optical flow calculation is carried out on successive star images preprocessed to remove background. Sensor calibration parameters, Poisson equation, and a least-squares method are then used to estimate the angular velocity vector components in the sensor rotating frame. A theoretical error budget is developed to estimate the expected angular rate accuracy as a function of camera parameters and star distribution in the field of view. The effectiveness of the proposed technique is tested by using star field scenes generated by a hardware-in-the-loop testing facility and acquired by a commercial-off-the shelf camera sensor. Simulated cases comprise rotations at different rates. Experimental results are presented which are consistent with theoretical estimates. In particular, very accurate angular velocity estimates are generated at lower slew rates, while in all cases the achievable accuracy in the estimation of the angular velocity component along boresight is about one order of magnitude worse than the other two components. PMID:24072023

  17. Satellite Angular Velocity Estimation Based on Star Images and Optical Flow Techniques

    Directory of Open Access Journals (Sweden)

    Giancarmine Fasano

    2013-09-01

    Full Text Available An optical flow-based technique is proposed to estimate spacecraft angular velocity based on sequences of star-field images. It does not require star identification and can be thus used to also deliver angular rate information when attitude determination is not possible, as during platform de tumbling or slewing. Region-based optical flow calculation is carried out on successive star images preprocessed to remove background. Sensor calibration parameters, Poisson equation, and a least-squares method are then used to estimate the angular velocity vector components in the sensor rotating frame. A theoretical error budget is developed to estimate the expected angular rate accuracy as a function of camera parameters and star distribution in the field of view. The effectiveness of the proposed technique is tested by using star field scenes generated by a hardware-in-the-loop testing facility and acquired by a commercial-off-the shelf camera sensor. Simulated cases comprise rotations at different rates. Experimental results are presented which are consistent with theoretical estimates. In particular, very accurate angular velocity estimates are generated at lower slew rates, while in all cases the achievable accuracy in the estimation of the angular velocity component along boresight is about one order of magnitude worse than the other two components.

  18. Heralded phase-contrast imaging using an orbital angular momentum phase-filter

    Science.gov (United States)

    Aspden, Reuben S.; Morris, Peter A.; He, Ruiqing; Chen, Qian; Padgett, Miles J.

    2016-05-01

    We utilise the position and orbital angular momentum (OAM) correlations between the signal and idler photons generated in the down-conversion process to obtain ghost images of a phase object. By using an OAM phase filter, which is non-local with respect to the object, the images exhibit isotropic edge-enhancement. This imaging technique is the first demonstration of a full-field, phase-contrast imaging system with non-local edge enhancement, and enables imaging of phase objects using significantly fewer photons than standard phase-contrast imaging techniques.

  19. Fast Single Image Super Resolution Reconstruction via Image Separation

    Directory of Open Access Journals (Sweden)

    Yichao Zhou

    2014-07-01

    Full Text Available In this work, a fast single image super resolution reconstruction (SRR approach via image separation has been proposed. Based on the assumption that the edges, corners, and textures in the image have different mathematical models, we apply different image SRR algorithms to process them individually. Thus, our approach is divided into three steps: 1 separating the given image into cartoon and texture subcomponent by nonlinear filter based image decomposition technique; 2 using improved local-self similarity model based algorithm to interpolate the cartoon subcomponent and the wavelet domain Hidden Markovian Tree (HMT model based algorithm to zoom the texture subcomponent; and 3 fusing the interpolated cartoon and texture subcomponents together to derive the recovered high-resolution images. Since the decomposition and super resolution algorithms in the proposed approach are mainly based on simple convolution and linear algebra computations, its efficiency can be guaranteed. Also, the simulated and real-life images experiments can validate the performance of our proposed algorithm when compared with some other state-of-the-art super-resolution approaches.

  20. Compressive sensing for high resolution radar imaging

    NARCIS (Netherlands)

    Anitori, L.; Otten, M.P.G.; Hoogeboom, P.

    2010-01-01

    In this paper we present some preliminary results on the application of Compressive Sensing (CS) to high resolution radar imaging. CS is a recently developed theory which allows reconstruction of sparse signals with a number of measurements much lower than what is required by the Shannon sampling th

  1. Smartphone microendoscopy for high resolution fluorescence imaging

    CERN Document Server

    Hong, Xiangqian; Mugler, Dale H; Yu, Bing

    2016-01-01

    High resolution optical endoscopes are increasingly used in diagnosis of various medical conditions of internal organs, such as the gastrointestinal tracts, but they are too expensive for use in resource-poor settings. On the other hand, smartphones with high resolution cameras and Internet access have become more affordable, enabling them to diffuse into most rural areas and developing countries in the past decade. In this letter we describe a smartphone microendoscope that can take fluorescence images with a spatial resolution of 3.1 {\\mu}m. Images collected from ex vivo, in vitro and in vivo samples using the device are also presented. The compact and cost-effective smartphone microendoscope may be envisaged as a powerful tool for detecting pre-cancerous lesions of internal organs in low and middle income countries.

  2. Resolution enhancement in nonlinear photoacoustic imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goy, Alexandre S.; Fleischer, Jason W. [Department of Electrical Engineering, Princeton University, Olden St., Princeton, New Jersey 08544 (United States)

    2015-11-23

    Nonlinear processes can be exploited to gain access to more information than is possible in the linear regime. Nonlinearity modifies the spectra of the excitation signals through harmonic generation, frequency mixing, and spectral shifting, so that features originally outside the detector range can be detected. Here, we present an experimental study of resolution enhancement for photoacoustic imaging of thin metal layers immersed in water. In this case, there is a threshold in the excitation below which no acoustic signal is detected. Above threshold, the nonlinearity reduces the width of the active area of the excitation beam, resulting in a narrower absorption region and thus improved spatial resolution. This gain is limited only by noise, as the active area of the excitation can be arbitrarily reduced when the fluence becomes closer to the threshold. Here, we demonstrate a two-fold improvement in resolution and quantify the image quality as the excitation fluence goes through threshold.

  3. Super-resolution of facial images in forensics scenarios

    DEFF Research Database (Denmark)

    Satiro, Joao; Nasrollahi, Kamal; Correia, Paulo;

    2015-01-01

    Forensics facial images are usually provided by surveillance cameras and are therefore of poor quality and resolution. Simple upsampling algorithms can not produce artifact-free higher resolution images from such low-resolution (LR) images. To deal with that, reconstruction-based super-resolution......Forensics facial images are usually provided by surveillance cameras and are therefore of poor quality and resolution. Simple upsampling algorithms can not produce artifact-free higher resolution images from such low-resolution (LR) images. To deal with that, reconstruction-based super...

  4. Comparison of super-resolution benefits for downsampled images and real low-resolution data

    NARCIS (Netherlands)

    Peng, Yuxi; Spreeuwers, Luuk; Gökberk, Berk; Veldhuis, Raymond

    2013-01-01

    Recently, more and more researchers are exploring the benefits of super-resolution methods on low-resolution face recognition. However, often results presented are obtained on downsampled high-resolution face images. Because downsampled images are different from real images taken at low resolution,

  5. Wavelet Domain Multidictionary Learning for Single Image Super-Resolution

    OpenAIRE

    Xiaomin Wu; Jiulun Fan; Jian Xu; Yanzi Wang

    2015-01-01

    Image super-resolution (SR) aims at recovering the high-frequency (HF) details of a high-resolution (HR) image according to the given low-resolution (LR) image and some priors about natural images. Learning the relationship of the LR image and its corresponding HF details to guide the reconstruction of the HR image is needed. In order to alleviate the uncertainty in HF detail prediction, the HR and LR images are usually decomposed into 4 subbands after 1-level discrete...

  6. All sky mapping of the Cosmic Microwave Background at 8' angular resolution with a 0.1 K bolometer: simulations

    OpenAIRE

    Giard, M.; Hivon, E.; Nguyen, C.; Gispert, R.; Górski, K. M.; Lange, A; Ristorcelli, I.

    1999-01-01

    We present simulations of observations with the 143 GHz channel of the Planck High Frequency Instrument (HFI). These simulations are performed over the entire sky, using the true angular resolution of this channel: 8 arcmin FWHM, 3.5 arcmin per pixel. We show that with measured 0.1 K bolometer performances, the sensitivity needed on the Cosmic Microwave Background (CMB) survey is obtained using simple and robust data processing techniques, including a destriping algorithm.

  7. Imaging Genetic Molecules At Atomic Resolution

    Science.gov (United States)

    Coles, L. Stephen

    1993-01-01

    Proposed method of imaging informational polymeric biological molecules at atomic resolution enables determination of sequences of component monomers about 10 to the 3rd power to 10 to the 4th power times as fast as conventional methods do. Accelerates research on genetic structures of animals and plants. Also contributes significantly to imaging processes like scanning electron microscopy (SEM), atomic-force microscopy (AFM), and scanning tunneling microscopy (STM) in cases in which necessary to locate or identify small specimens on relatively large backgrounds and subtract background images to obtain images of specimens in isolation. V-grooves on silicon wafer laid out in square pattern, intersections of which marked to identify coordinates. Specimen molecules held in grooves for reproducible positioning and scanning by AFM or STM.

  8. Computed tomography with selectable image resolution

    International Nuclear Information System (INIS)

    A computed tomography system x-ray detector has a central group of half-width detector elements and groups of full-width elements on each side of the central group. To obtain x-ray attenuation data for whole body layers, the half-width elements are switched effectively into paralleled pairs so all elements act like full-width elements and an image of normal resolution is obtained. For narrower head layers, the elements in the central group are used as half-width elements so resolution which is twice as great as normal is obtained. The central group is also used in the half-width mode and the outside groups are used in the full-width mode to obtain a high resolution image of a body zone within a full body layer. In one embodiment data signals from the detector are switched by electronic multiplexing and in another embodiment a processor chooses the signals for the various kinds of images that are to be reconstructed. (author)

  9. SINGLE IMAGE SUPER RESOLUTION IN SPATIAL AND WAVELET DOMAIN

    Directory of Open Access Journals (Sweden)

    Sapan Naik

    2013-08-01

    Full Text Available Recently single image super resolution is very important research area to generate high-resolution image from given low-resolution image. Algorithms of single image resolution are mainly based on wavelet domain and spatial domain. Filter’s support to model the regularity of natural images is exploited in wavelet domain while edges of images get sharp during up sampling in spatial domain. Here single image super resolution algorithm is presented which based on both spatial and wavelet domain and take the advantage of both. Algorithm is iterative and use back projection to minimize reconstruction error. Wavelet based denoising method is also introduced to remove noise.

  10. Resolution limits for wave equation imaging

    KAUST Repository

    Huang, Yunsong

    2014-08-01

    Formulas are derived for the resolution limits of migration-data kernels associated with diving waves, primary reflections, diffractions, and multiple reflections. They are applicable to images formed by reverse time migration (RTM), least squares migration (LSM), and full waveform inversion (FWI), and suggest a multiscale approach to iterative FWI based on multiscale physics. That is, at the early stages of the inversion, events that only generate low-wavenumber resolution should be emphasized relative to the high-wavenumber resolution events. As the iterations proceed, the higher-resolution events should be emphasized. The formulas also suggest that inverting multiples can provide some low- and intermediate-wavenumber components of the velocity model not available in the primaries. Finally, diffractions can provide twice or better the resolution than specular reflections for comparable depths of the reflector and diffractor. The width of the diffraction-transmission wavepath is approximately λ at the diffractor location for the diffraction-transmission wavepath. © 2014 Elsevier B.V.

  11. Isotope specific resolution recovery image reconstruction in high resolution PET imaging

    Energy Technology Data Exchange (ETDEWEB)

    Kotasidis, Fotis A. [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva, Switzerland and Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, M20 3LJ, Manchester (United Kingdom); Angelis, Georgios I. [Faculty of Health Sciences, Brain and Mind Research Institute, University of Sydney, NSW 2006, Sydney (Australia); Anton-Rodriguez, Jose; Matthews, Julian C. [Wolfson Molecular Imaging Centre, MAHSC, University of Manchester, Manchester M20 3LJ (United Kingdom); Reader, Andrew J. [Montreal Neurological Institute, McGill University, Montreal QC H3A 2B4, Canada and Department of Biomedical Engineering, Division of Imaging Sciences and Biomedical Engineering, King' s College London, St. Thomas’ Hospital, London SE1 7EH (United Kingdom); Zaidi, Habib [Division of Nuclear Medicine and Molecular Imaging, Geneva University Hospital, CH-1211 Geneva (Switzerland); Geneva Neuroscience Centre, Geneva University, CH-1205 Geneva (Switzerland); Department of Nuclear Medicine and Molecular Imaging, University of Groningen, University Medical Center Groningen, PO Box 30 001, Groningen 9700 RB (Netherlands)

    2014-05-15

    Purpose: Measuring and incorporating a scanner-specific point spread function (PSF) within image reconstruction has been shown to improve spatial resolution in PET. However, due to the short half-life of clinically used isotopes, other long-lived isotopes not used in clinical practice are used to perform the PSF measurements. As such, non-optimal PSF models that do not correspond to those needed for the data to be reconstructed are used within resolution modeling (RM) image reconstruction, usually underestimating the true PSF owing to the difference in positron range. In high resolution brain and preclinical imaging, this effect is of particular importance since the PSFs become more positron range limited and isotope-specific PSFs can help maximize the performance benefit from using resolution recovery image reconstruction algorithms. Methods: In this work, the authors used a printing technique to simultaneously measure multiple point sources on the High Resolution Research Tomograph (HRRT), and the authors demonstrated the feasibility of deriving isotope-dependent system matrices from fluorine-18 and carbon-11 point sources. Furthermore, the authors evaluated the impact of incorporating them within RM image reconstruction, using carbon-11 phantom and clinical datasets on the HRRT. Results: The results obtained using these two isotopes illustrate that even small differences in positron range can result in different PSF maps, leading to further improvements in contrast recovery when used in image reconstruction. The difference is more pronounced in the centre of the field-of-view where the full width at half maximum (FWHM) from the positron range has a larger contribution to the overall FWHM compared to the edge where the parallax error dominates the overall FWHM. Conclusions: Based on the proposed methodology, measured isotope-specific and spatially variant PSFs can be reliably derived and used for improved spatial resolution and variance performance in resolution

  12. GRANULOMETRIC MAPS FROM HIGH RESOLUTION SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    Catherine Mering

    2011-05-01

    Full Text Available A new method of land cover mapping from satellite images using granulometric analysis is presented here. Discontinuous landscapes such as steppian bushes of semi arid regions and recently growing urban settlements are especially concerned by this study. Spatial organisations of the land cover are quantified by means of the size distribution analysis of the land cover units extracted from high resolution remotely sensed images. A granulometric map is built by automatic classification of every pixel of the image according to the granulometric density inside a sliding neighbourhood. Granulometric mapping brings some advantages over traditional thematic mapping by remote sensing by focusing on fine spatial events and small changes in one peculiar category of the landscape.

  13. Dual Resolution Images from Paired Fingerprint Cards

    Science.gov (United States)

    NIST Dual Resolution Images from Paired Fingerprint Cards (PC database for purchase)   NIST Special Database 30 is being distributed for use in development and testing of fingerprint compression and fingerprint matching systems. The database allows the user to develop and evaluate data compression algorithms for fingerprint images scanned at both 19.7 ppmm (500 dpi) and 39.4 ppmm (1000 dpi). The data consist of 36 ten-print paired cards with both the rolled and plain images scanned at 19.7 and 39.4 pixels per mm. A newer version of the compression/decompression software on the CDROM can be found at the website http://www.nist.gov/itl/iad/ig/nigos.cfm as part of the NBIS package.

  14. Effects of spatial resolution ratio in image fusion

    Science.gov (United States)

    Ling, Y.; Ehlers, M.; Usery, E.L.; Madden, M.

    2008-01-01

    In image fusion, the spatial resolution ratio can be defined as the ratio between the spatial resolution of the high-resolution panchromatic image and that of the low-resolution multispectral image. This paper attempts to assess the effects of the spatial resolution ratio of the input images on the quality of the fused image. Experimental results indicate that a spatial resolution ratio of 1:10 or higher is desired for optimal multisensor image fusion provided the input panchromatic image is not downsampled to a coarser resolution. Due to the synthetic pixels generated from resampling, the quality of the fused image decreases as the spatial resolution ratio decreases (e.g. from 1:10 to 1:30). However, even with a spatial resolution ratio as small as 1:30, the quality of the fused image is still better than the original multispectral image alone for feature interpretation. In cases where the spatial resolution ratio is too small (e.g. 1:30), to obtain better spectral integrity of the fused image, one may downsample the input high-resolution panchromatic image to a slightly lower resolution before fusing it with the multispectral image.

  15. Associations of water and methanol masers at milli-arcsec angular resolution in two high-mass young stellar objects

    CERN Document Server

    Goddi, C; Sanna, A; Cesaroni, R; Minier, V

    2006-01-01

    Most previous high-angular (<0.1 arcsec) resolution studies of molecular masers in high-mass star forming regions (SFRs) have concentrated mainly on either water or methanol masers. While high-angular resolution observations have clarified that water masers originate from shocks associated with protostellar jets, different environments have been proposed in several sources to explain the origin of methanol masers. Tha aim of the paper is to investigate the nature of the methanol maser birthplace in SFRs and the association between the water and methanol maser emission in the same young stellar object. We have conducted phase-reference Very Long Baseline Interferometry (VLBI) observations of water and methanol masers toward two high-mass SFRs, Sh 2-255 IR and AFGL 5142. In Sh 2-255 IR water masers are aligned along a direction close to the orientation of the molecular outflow observed on angular scales of 1-10 arcsec, tracing possibly the disk-wind emerging from the disk atmosphere. In AFGL 5142 water maser...

  16. Limiting liability via high resolution image processing

    Energy Technology Data Exchange (ETDEWEB)

    Greenwade, L.E.; Overlin, T.K.

    1996-12-31

    The utilization of high resolution image processing allows forensic analysts and visualization scientists to assist detectives by enhancing field photographs, and by providing the tools and training to increase the quality and usability of field photos. Through the use of digitized photographs and computerized enhancement software, field evidence can be obtained and processed as `evidence ready`, even in poor lighting and shadowed conditions or darkened rooms. These images, which are most often unusable when taken with standard camera equipment, can be shot in the worst of photographic condition and be processed as usable evidence. Visualization scientists have taken the use of digital photographic image processing and moved the process of crime scene photos into the technology age. The use of high resolution technology will assist law enforcement in making better use of crime scene photography and positive identification of prints. Valuable court room and investigation time can be saved and better served by this accurate, performance based process. Inconclusive evidence does not lead to convictions. Enhancement of the photographic capability helps solve one major problem with crime scene photos, that if taken with standard equipment and without the benefit of enhancement software would be inconclusive, thus allowing guilty parties to be set free due to lack of evidence.

  17. Rapid hologram generation utilizing layer-based approach and graphic rendering for realistic three-dimensional image reconstruction by angular tiling

    Science.gov (United States)

    Chen, Jhen-Si; Chu, Daping; Smithwick, Quinn

    2014-03-01

    An approach of rapid hologram generation for the realistic three-dimensional (3-D) image reconstruction based on the angular tiling concept is proposed, using a new graphic rendering approach integrated with a previously developed layer-based method for hologram calculation. A 3-D object is simplified as layered cross-sectional images perpendicular to a chosen viewing direction, and our graphics rendering approach allows the incorporation of clear depth cues, occlusion, and shading in the generated holograms for angular tiling. The combination of these techniques together with parallel computing reduces the computation time of a single-view hologram for a 3-D image of extended graphics array resolution to 176 ms using a single consumer graphics processing unit card.

  18. Ultra-high resolution computed tomography imaging

    Energy Technology Data Exchange (ETDEWEB)

    Paulus, Michael J. (Knoxville, TN); Sari-Sarraf, Hamed (Knoxville, TN); Tobin, Jr., Kenneth William (Harriman, TN); Gleason, Shaun S. (Knoxville, TN); Thomas, Jr., Clarence E. (Knoxville, TN)

    2002-01-01

    A method for ultra-high resolution computed tomography imaging, comprising the steps of: focusing a high energy particle beam, for example x-rays or gamma-rays, onto a target object; acquiring a 2-dimensional projection data set representative of the target object; generating a corrected projection data set by applying a deconvolution algorithm, having an experimentally determined a transfer function, to the 2-dimensional data set; storing the corrected projection data set; incrementally rotating the target object through an angle of approximately 180.degree., and after each the incremental rotation, repeating the radiating, acquiring, generating and storing steps; and, after the rotating step, applying a cone-beam algorithm, for example a modified tomographic reconstruction algorithm, to the corrected projection data sets to generate a 3-dimensional image. The size of the spot focus of the beam is reduced to not greater than approximately 1 micron, and even to not greater than approximately 0.5 microns.

  19. The Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII): High Angular Resolution Astronomy at Far-Infrared Wavelengths

    Science.gov (United States)

    Rinehart, Stephen A.

    2008-01-01

    Astronomical studies at infrared wavelengths have dramatically improved our understanding of the universe, and observations with Spitzer, the upcoming Herschel mission. and SOFIA will continue to provide exciting new discoveries. The comparatively low spatial resolution of these missions, however. is insufficient to resolve the physical scales on which mid- to far-infrared emission arises, resulting in source and structure ambiguities that limit our ability to answer key science questions. Interferometry enables high angular resolution at these wavelengths. We have proposed a new high altitude balloon experiment, the Balloon Experimental Twin Telescope for Infrared Interferometry (BETTII). High altitude operation makes far-infrared (30- 300micron) observations possible, and BETTII's 8-meter baseline provides unprecedented angular resolution (-0.5 arcsec) in this band. BETTII will use a double- Fourier instrument to simultaneously obtain both spatial and spectral informatioT. he spatially resolved spectroscopy provided by BETTII will address key questions about the nature of disks in young cluster stars and active galactic nuclei and the envelopes of evolved stars. BETTII will also lay the groundwork for future space interferometers.

  20. A Survey of the Polarized Emission from the Galactic Plane at 1420 MHz with Arcminute Angular Resolution

    CERN Document Server

    Landecker, T L; Reid, R I; Reich, P; Wolleben, M; Kothes, R; Uyaniker, B; Gray, A D; Del Rizzo, D; Furst, E; Taylor, A R; Wielebinski, R

    2010-01-01

    Context: Observations of polarized emission are a significant source of information on the magnetic field that pervades the Interstellar Medium of the Galaxy. Despite the acknowledged importance of the magnetic field in interstellar processes, our knowledge of field configurations on all scales is seriously limited. Aims: This paper describes an extensive survey of polarized Galactic emission at 1.4 GHz that provides data with arcminute resolution and complete coverage of all structures from the broadest angular scales to the resolution limit, giving information on the magneto-ionic medium over a wide range of interstellar environments. Methods: Data from the DRAO Synthesis Telescope, the Effelsberg 100-m Telescope, and the DRAO 26-m Telescope have been combined. Angular resolution is ~1' and the survey extends from l = 66 deg to l = 175 deg over a range -3 deg < b < 5 deg along the northern Galactic plane, with a high-latitude extension from l = 101 deg to l = 116 deg up to b = 17.5 deg. This is the fi...

  1. Super-resolution photoacoustic fluctuation imaging with multiple speckle illumination

    CERN Document Server

    Chaigne, Thomas; Allain, Marc; Katz, Ori; Gigan, Sylvain; Sentenac, Anne; Bossy, Emmanuel

    2015-01-01

    In deep tissue photoacoustic imaging, the spatial resolution is inherently limited by acoustic diffraction. Moreover, as the ultrasound attenuation increases with frequency, resolution is often traded-off for penetration depth. Here we report on super-resolution photoacoustic imaging by use of multiple speckle illumination. Specifically, we show that the analysis of second-order fluctuations of the photoacoustic images combined with image deconvolution enables resolving optically absorbing structures beyond the acoustic diffraction limit. A resolution increase of almost a factor 2 is demonstrated experimentally. Our method introduces a new framework that could potentially lead to deep tissue photoacoustic imaging with sub-acoustic resolution.

  2. Reproducible high-resolution multispectral image acquisition in dermatology

    Science.gov (United States)

    Duliu, Alexandru; Gardiazabal, José; Lasser, Tobias; Navab, Nassir

    2015-07-01

    Multispectral image acquisitions are increasingly popular in dermatology, due to their improved spectral resolution which enables better tissue discrimination. Most applications however focus on restricted regions of interest, imaging only small lesions. In this work we present and discuss an imaging framework for high-resolution multispectral imaging on large regions of interest.

  3. High-resolution colorimetric imaging of paintings

    Science.gov (United States)

    Martinez, Kirk; Cupitt, John; Saunders, David R.

    1993-05-01

    With the aim of providing a digital electronic replacement for conventional photography of paintings, a scanner has been constructed based on a 3000 X 2300 pel resolution camera which is moved precisely over a 1 meter square area. Successive patches are assembled to form a mosaic which covers the whole area at c. 20 pels/mm resolution, which is sufficient to resolve the surface textures, particularly craquelure. To provide high color accuracy, a set of seven broad-band interference filters are used to cover the visible spectrum. A calibration procedure based upon a least-mean-squares fit to the color of patches from a Macbeth Colorchecker chart yields an average color accuracy of better than 3 units in the CMC uniform color space. This work was mainly carried out as part of the VASARI project funded by the European Commission's ESPRIT program, involving companies and galleries from around Europe. The system is being used to record images for conservation research, for archival purposes and to assist in computer-aided learning in the field of art history. The paper will describe the overall system design, including the selection of the various hardware components and the design of controlling software. The theoretical basis for the color calibration methodology is described as well as the software for its practical implementation. The mosaic assembly procedure and some of the associated image processing routines developed are described. Preliminary results from the research will be presented.

  4. Molecular outflows and hot molecular core in G24.78+0.08 at sub-arcsecond angular resolution

    OpenAIRE

    Beltran, M. T.; Cesaroni, R.; Zhang, Q; Galvan-Madrid, R.; Beuther, H.; Fallscheer, C.; Neri, R.; Codella, C.

    2011-01-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims. We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods. We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 m...

  5. Gibbs artifact reduction for POCS super-resolution image reconstruction

    Institute of Scientific and Technical Information of China (English)

    Chuangbai XIAO; Jing YU; Kaina SU

    2008-01-01

    The topic of super-resolution image reconstruc-tion has recently received considerable attention among the research community. Super-resolution image reconstruc-tion methods attempt to create a single high-resolution image from a number of low-resolution images (or a video sequence). The method of projections onto convex sets (POCS) for super-resolution image reconstruction attracts many researchers' attention. In this paper, we propose an improvement to reduce the amount of Gibbs artifacts pre-senting on the edges of the high-resolution image recon-structed by the POCS method. The proposed method weights the blur PSF centered at an edge pixel with an exponential function, and consequently decreases the coef-ficients of the PSF in the direction orthogonal to the edge. Experiment results show that the modification reduces effectively the visibility of Gibbs artifacts on edges and improves obviously the quality of the reconstructed high-resolution image.

  6. Angular Cheilitis

    Science.gov (United States)

    ... A This image displays a frequent location for candida infection (angular cheilitis), the corners of the mouth. Overview ... infection, those affected may also have thrush (oral candidiasis). The areas are generally slightly painful. The condition ...

  7. Noise reduction methods in analysis of near infrared lunar occultation light curves for high angular resolution measurements

    CERN Document Server

    Baug, Tapas

    2013-01-01

    Lunar occultation (LO) technique in the near-infrared provides angular resolution down to milliarcseconds on the occulted source even with ground-based 1m class telescopes. LO observations are limited to brighter objects because they require high signal to noise ratio (S/N ~ 40) for proper extraction of angular diameter values. Hence, methods to improve the S/N ratio by reducing noise using Fourier and Wavelet transforms have been explored in this study. A sample of 54 near-infrared LO light curves observed with IR Camera at Mt Abu observatory has been used. It is seen that both Fourier and Wavelet methods have shown improvement in S/N, compared to the original data. However, the application of wavelet transforms results in slight smoothening of the fringes resulting in a higher angular diameter value. Fourier transforms which reduce discrete noise frequencies do not distort the fringe. Fourier transform method seems to be effective in S/N improvement, as well as improved model fit particularly in the fainter...

  8. High resolution neutron imaging for inertial confinement fusion experiments

    International Nuclear Information System (INIS)

    A high resolution neutron imaging system (NIS) is developed and tested on the OMEGA laser facility for inertial confinement fusion (ICF) experiments. This diagnostic uses a coded imaging technique with a high resolution neutron camera. Over the past few years, this detector was improved and neutron images can now be acquired on OMEGA with a 20 μm spatial resolution in the source plane and good signal to noise ratio with both a penumbral and an annular imaging technique. (authors)

  9. Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center. II. Additional observations

    CERN Document Server

    Richichi, A; Mason, E

    2008-01-01

    We present lunar occultation observations obtained in August 2006 with the recently demonstrated burst mode of the ISAAC instrument at the ESO VLT. The results presented here follow the previously reported observations carried out in March 2006 on a similar but unrelated set of sources. Interstellar extinction in the inner regions of the galactic bulge amounts to tens of magnitudes at visual wavelengths. As a consequence, the majority of sources in that area are poorly studied and large numbers of potentially interesting sources such as late-type giants with circumstellar shells, stellar masers, infrared stars, remain excluded from the typical investigations which are carried out in less problematic regions. Also undetected are a large numbers of binaries. By observing LO events in this region, we gain the means to investigate at least a selected number of sources with an unprecedented combination of sensitivity and angular resolution. The LO technique permits to achieve mas resolution with a sensitivity of K...

  10. Far-field super-resolution imaging of resonant multiples.

    Science.gov (United States)

    Guo, Bowen; Huang, Yunsong; Røstad, Anders; Schuster, Gerard

    2016-05-01

    We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images. PMID:27386521

  11. Far-field super-resolution imaging of resonant multiples

    KAUST Repository

    Guo, B.

    2016-05-20

    We demonstrate for the first time that seismic resonant multiples, usually considered as noise, can be used for super-resolution imaging in the far-field region of sources and receivers. Tests with both synthetic data and field data show that resonant multiples can image reflector boundaries with resolutions more than twice the classical resolution limit. Resolution increases with the order of the resonant multiples. This procedure has important applications in earthquake and exploration seismology, radar, sonar, LIDAR (light detection and ranging), and ultrasound imaging, where the multiples can be used to make high-resolution images.

  12. Resolution enhancement phase-contrast imaging by microsphere digital holography

    Science.gov (United States)

    Wang, Yunxin; Guo, Sha; Wang, Dayong; Lin, Qiaowen; Rong, Lu; Zhao, Jie

    2016-05-01

    Microsphere has shown the superiority of super-resolution imaging in the traditional 2D intensity microscope. Here a microsphere digital holography approach is presented to realize the resolution enhancement phase-contrast imaging. The system is designed by combining the microsphere with the image-plane digital holography. A microsphere very close to the object can increase the resolution by transforming the object wave from the higher frequency to the lower one. The resolution enhancement amplitude and phase images can be retrieved from a single hologram. The experiments are carried on the 1D and 2D gratings, and the results demonstrate that the observed resolution has been improved, meanwhile, the phase-contrast image is obtained. The proposed method can improve the transverse resolution in all directions based on a single exposure. Furthermore, this system has extended the application of the microsphere from the conventional 2D microscopic imaging to 3D phase-contrast microscopic imaging.

  13. High resolution imaging detectors and applications

    CERN Document Server

    Saha, Swapan K

    2015-01-01

    Interferometric observations need snapshots of very high time resolution of the order of (i) frame integration of about 100 Hz or (ii) photon-recording rates of several megahertz (MHz). Detectors play a key role in astronomical observations, and since the explanation of the photoelectric effect by Albert Einstein, the technology has evolved rather fast. The present-day technology has made it possible to develop large-format complementary metal oxide–semiconductor (CMOS) and charge-coupled device (CCD) array mosaics, orthogonal transfer CCDs, electron-multiplication CCDs, electron-avalanche photodiode arrays, and quantum-well infrared (IR) photon detectors. The requirements to develop artifact-free photon shot noise-limited images are higher sensitivity and quantum efficiency, reduced noise that includes dark current, read-out and amplifier noise, smaller point-spread functions, and higher spectral bandwidth. This book aims to address such systems, technologies and design, evaluation and calibration, control...

  14. Moderate Resolution Imaging Spectroradiometer (MODIS) Overview

    Science.gov (United States)

    U.S. Geological Survey

    2008-01-01

    The Moderate Resolution Imaging Spectroradiometer (MODIS) is an instrument that collects remotely sensed data used by scientists for monitoring, modeling, and assessing the effects of natural processes and human actions on the Earth's surface. The continual calibration of the MODIS instruments, the refinement of algorithms used to create higher-level products, and the ongoing product validation make MODIS images a valuable time series (2000-present) of geophysical and biophysical land-surface measurements. Carried on two National Aeronautics and Space Administration (NASA) Earth Observing System (EOS) satellites, MODIS acquires morning (EOS-Terra) and afternoon (EOS-Aqua) views almost daily. Terra data acquisitions began in February 2000 and Aqua data acquisitions began in July 2002. Land data are generated only as higher-level products, removing the burden of common types of data processing from the user community. MODIS-based products describing ecological dynamics, radiation budget, and land cover are projected onto a sinusoidal mapping grid and distributed as 10- by 10-degree tiles at 250-, 500-, or 1,000-meter spatial resolution. Some products are also created on a 0.05-degree geographic grid to support climate modeling studies. All MODIS products are distributed in the Hierarchical Data Format-Earth Observing System (HDF-EOS) file format and are available through file transfer protocol (FTP) or on digital video disc (DVD) media. Versions 4 and 5 of MODIS land data products are currently available and represent 'validated' collections defined in stages of accuracy that are based on the number of field sites and time periods for which the products have been validated. Version 5 collections incorporate the longest time series of both Terra and Aqua MODIS data products.

  15. The multiplicity of massive stars: A high angular resolution survey with the HST fine guidance sensor

    Energy Technology Data Exchange (ETDEWEB)

    Aldoretta, E. J.; Gies, D. R.; Henry, T. J.; Jao, W.-C.; Norris, R. P., E-mail: emily@astro.umontreal.ca, E-mail: gies@chara.gsu.edu, E-mail: thenry@chara.gsu.edu, E-mail: jao@chara.gsu.edu, E-mail: norris@chara.gsu.edu [Center for High Angular Resolution Astronomy, Department of Physics and Astronomy, Georgia State University, P. O. Box 5060, Atlanta, GA 30302-5060 (United States); and others

    2015-01-01

    We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars. The sample of 224 stars is comprised mainly of Galactic O- and B-type stars and luminous blue variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to the detection of companions with an angular separation between 0.″01 and 1.″0 and brighter than △m=5. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations, field stars, and runaway stars. These results confirm the high multiplicity fraction, especially among massive stars in clusters and associations. We show that the period distribution is approximately flat in increments of logP. We identify a number of systems of potential interest for long-term orbital determinations, and we note the importance of some of these companions for the interpretation of the radial velocities and light curves of close binaries that have third companions.

  16. The multiplicity of massive stars: A high angular resolution survey with the HST fine guidance sensor

    International Nuclear Information System (INIS)

    We present the results of an all-sky survey made with the Fine Guidance Sensor on the Hubble Space Telescope to search for angularly resolved binary systems among massive stars. The sample of 224 stars is comprised mainly of Galactic O- and B-type stars and luminous blue variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to the detection of companions with an angular separation between 0.″01 and 1.″0 and brighter than △m=5. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations, field stars, and runaway stars. These results confirm the high multiplicity fraction, especially among massive stars in clusters and associations. We show that the period distribution is approximately flat in increments of logP. We identify a number of systems of potential interest for long-term orbital determinations, and we note the importance of some of these companions for the interpretation of the radial velocities and light curves of close binaries that have third companions.

  17. The Multiplicity of Massive Stars: A High Angular Resolution Survey with the HST Fine Guidance Sensor

    CERN Document Server

    Aldoretta, E J; Gies, D R; Nelan, E P; Wallace, D J; Hartkopf, W I; Henry, T J; Jao, W -C; Apellániz, J Maíz; Mason, B D; Moffat, A F J; Norris, R P; Richardson, N D; Williams, S J

    2014-01-01

    We present the results of an all-sky survey made with the Fine Guidance Sensor on Hubble Space Telescope to search for angularly resolved binary systems among the massive stars. The sample of 224 stars is comprised mainly of Galactic O- and B-type stars and Luminous Blue Variables, plus a few luminous stars in the Large Magellanic Cloud. The FGS TRANS mode observations are sensitive to detection of companions with an angular separation between 0."01 and 1."0 and brighter than $\\triangle m = 5$. The FGS observations resolved 52 binary and 6 triple star systems and detected partially resolved binaries in 7 additional targets (43 of these are new detections). These numbers yield a companion detection frequency of 29% for the FGS survey. We also gathered literature results on the numbers of close spectroscopic binaries and wider astrometric binaries among the sample, and we present estimates of the frequency of multiple systems and the companion frequency for subsets of stars residing in clusters and associations...

  18. From Exoplanets to Quasars: Detection of Potential Damped Lyman Alpha Absorbing Galaxies Using Angular Differential Imaging

    CERN Document Server

    Johnson-Groh, Mara; Ellison, Sara L

    2016-01-01

    The advantages of angular differential imaging (ADI) has been previously untested in imaging the host galaxies of damped Lyman alpha (DLA) systems. In this pilot study, we present the first application of ADI to directly imaging the host galaxy of the DLA seen towards the quasar J1431+3952. K-band imaging of the field surrounding J1431+3952 was obtained on the Gemini North telescope with the adaptive optics system and a laser guide star. We computed a sensitivity curve that demonstrates the sensitivity of our observations as a function of K-band magnitude, impact parameter and DLA angular size. For an impact parameter of 0.5" (3.4 kpc at the redshift of the absorber) our mass sensitivity is log (M_star/M_sun) ~ 9.2 and drops to ~ 9.0 at separations beyond ~ 6 kpc for the smallest size model galaxy. Three candidate galaxies are identified within 5". Stellar masses were computed from the K-band photometry yielding values of log (M_star/M_sun) ~ 9.9, 9.7 and 11.1 respectively. The likely identification of the ab...

  19. Perceived Image Quality on Mobile Phones with Different Screen Resolution

    OpenAIRE

    Wenjie Zou; Jiarun Song; Fuzheng Yang

    2016-01-01

    The diverse display screen imposes significant challenges for assessing the perceptual media quality across different mobile devices. In this paper, the perceived image quality on different mobile phones is investigated. Firstly, subjective experiments for image quality evaluation are implemented on 9 popular mobile phones and a broadcast-quality monitor to evaluate the impact on perceived image quality regarding the screen resolution, screen size, image resolution, and image coding quality. ...

  20. A three-channel miniaturized optical system for multi-resolution imaging

    Science.gov (United States)

    Belay, Gebirie Y.; Ottevaere, Heidi; Meuret, Youri; Thienpont, Hugo

    2013-09-01

    Inspired by the natural compound eyes of insects, multichannel imaging systems embrace many channels that scramble their entire Field-Of-View (FOV). Our aim in this work was to attain multi-resolution capability into a multi-channel imaging system by manipulating the available channels to possess different imaging properties (focal length, angular resolution). We have designed a three-channel imaging system where the first and third channels have highest and lowest angular resolution of 0.0096° and 0.078° and narrowest and widest FOVs of 7° and 80°, respectively. The design of the channels has been done for a single wavelength of 587.6 nm using CODE V. The three channels each consist of 4 aspherical lens surfaces and an absorbing baffle that avoids crosstalk among the neighbouring channels. The aspherical lens surfaces have been fabricated in PMMA by ultra-precision diamond tooling and the baffles by metal additive manufacturing. The profiles of the fabricated lens surfaces have been measured with an accurate multi-sensor coordinate measuring machine and compared with the corresponding profiles of the designed lens surfaces. The fabricated lens profiles are then incorporated into CODE V to realistically model the three channels and also compare their performances with those of the nominal design. We can conclude that the performances of the two latter models are in a good agreement.

  1. Reproducing kernel hilbert space based single infrared image super resolution

    Science.gov (United States)

    Chen, Liangliang; Deng, Liangjian; Shen, Wei; Xi, Ning; Zhou, Zhanxin; Song, Bo; Yang, Yongliang; Cheng, Yu; Dong, Lixin

    2016-07-01

    The spatial resolution of Infrared (IR) images is limited by lens optical diffraction, sensor array pitch size and pixel dimension. In this work, a robust model is proposed to reconstruct high resolution infrared image via a single low resolution sampling, where the image features are discussed and classified as reflective, cooled emissive and uncooled emissive based on infrared irradiation source. A spline based reproducing kernel hilbert space and approximative heaviside function are deployed to model smooth part and edge component of image respectively. By adjusting the parameters of heaviside function, the proposed model can enhance distinct part of images. The experimental results show that the model is applicable on both reflective and emissive low resolution infrared images to improve thermal contrast. The overall outcome produces a high resolution IR image, which makes IR camera better measurement accuracy and observes more details at long distance.

  2. Spectral methods for spatial resolution improvement of digital images

    Institute of Scientific and Technical Information of China (English)

    郝鹏威; 徐冠华; 朱重光

    1999-01-01

    A general matrix formula is proposed for signal spectral aliasing of various or mutual resolution, the concept of spectral aliasing matrix is introduced, and some general spectral methods for spatial resolution improvement from multiframes of undersampled digital images are discussed. A simplified iterative method of parallel row-action projection for spectral de-aliasing is also given. The method can be applied to multiframe images with various spatial resolution,relative displacement, dissimilar point spread function, different image radiance, and additive random noise. Some experiments with a resolution test pattern and an image of vertical fin performed the convergence and the effectiveness of the algorithms.

  3. Active-Pixel Image Sensors With Programmable Resolution

    Science.gov (United States)

    Kemeny, Sabrina E.; Fossum, Eric R.; Pain, Bedabrata; Nakamura, Junichi; Matthies, Larry H.

    1996-01-01

    Active-pixel image sensors with programmable resolution proposed for use in applications in which speed and efficiency of processing of image data enhanced by providing those data at varying resolutions. Such applications include modeling of biological vision, stereoscopic range-finding, recognition of patterns, tracking targets, and progressive transmission of compressed images. In target-tracking application, sensor initially forms low-resolution image from which area of interest identified, then sensor set at high resolution for examination of identified area. Outputs of contiguous pixels combined. Sensor of this type made to act as though it comprised fewer and larger pixels.

  4. Tomographic imaging of the angular-dependent coherent-scatter cross section.

    Science.gov (United States)

    Westmore, M S; Fenster, A; Cunningham, I A

    1997-01-01

    A new special-purpose computed tomographic (CT) imaging system is described which produces images based on measurements of the low-angle (0-10 degrees) x-ray diffraction properties of an object. Low-angle scatter in the diagnostic x-ray energy range is dominated by coherent scatter, and the system uses first-generation CT geometry to acquire a diffraction pattern for each pencil beam. The patterns are used to reconstruct a series of images which represent the coherent-scatter intensity at a series of scatter angles. To demonstrate the potential of coherent-scatter CT (CSCT), the scanner has been built and used to image a phantom consisting of a water-filled Lucite cylinder containing rods of polyethylene, Lucite, polycarbonate, and nylon. In this paper, the system is described and a sequence of CSCT images of this phantom is shown. Coherent-scatter cross sections of these materials are generated for each pixel from this sequence of images and compared with cross sections measured separately. The resulting excellent agreement shows that the angular-dependent coherent-scatter cross section can be accurately imaged in a tomographic slice through an object. These cross sections give material-specific information about the object. The long-term goal of this research is to make measurements of bone-mineral content for every pixel in a tomographic slice. PMID:9029536

  5. Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes

    OpenAIRE

    Fernique, P.; Allen, M. G.; Boch, T.; Oberto, A.; Pineau, F-X.; Durand, D.; Bot, C.; Cambresy, L.; Derriere, S.; Genova, F; Bonnarel, F

    2015-01-01

    Scientific exploitation of the ever increasing volumes of astronomical data requires efficient and practical methods for data access, visualisation, and analysis. Hierarchical sky tessellation techniques enable a multi-resolution approach to organising data on angular scales from the full sky down to the individual image pixels. Aims. We aim to show that the Hierarchical progressive survey (HiPS) scheme for describing astronomical images, source catalogues, and three-dimensional data cubes is...

  6. A deep look at the nuclear region of UGC 5101 through high angular resolution mid-IR data with GTC/CanariCam

    CERN Document Server

    Martínez-Paredes, M; Aretxaga, I; Almeida, C Ramos; Hernán-Caballero, A; González-Martín, O; Pereira-Santaella, M; Packham, C; Ramos, A Asensio; Díaz-Santos, T; Elitzur, M; Esquej, P; García-Bernete, I; Imanishi, M; Levenson, N A; Espinosa, J M Rodríguez

    2015-01-01

    We present an analysis of the nuclear infrared (IR, 1.6 to 18 $\\mu$m) emission of the ultraluminous IR galaxy UGC 5101 to derive the properties of its active galactic nucleus (AGN) and its obscuring material. We use new mid-IR high angular resolution ($0.3-0.5$ arcsec) imaging using the Si-2 filter ($\\lambda_{C}=8.7\\, \\mu$m) and $7.5-13$ $\\mu$m spectroscopy taken with CanariCam (CC) on the 10.4m Gran Telescopio CANARIAS. We also use archival HST/NICMOS and Subaru/COMICS imaging and Spitzer/IRS spectroscopy. We estimate the near- and mid-IR unresolved nuclear emission by modelling the imaging data with GALFIT. We decompose the Spitzer/IRS and CC spectra using a power-law component, which represents the emission due to dust heated by the AGN, and a starburst component, both affected by foreground extinction. We model the resulting unresolved near- and mid-IR, and the starburst subtracted CC spectrum with the CLUMPY torus models of Nenkova et al. The derived geometrical properties of the torus, including the lar...

  7. Resolution and noise in ghost imaging with classical thermal light

    Institute of Scientific and Technical Information of China (English)

    Cheng Jing; Han Shen-Sheng; Yan Yi-Jing

    2006-01-01

    The resolution and classical noise in ghost imaging with a classical thermal light are investigated theoretically. For ghost imaging with a Gaussian Schell model source, the dependences of the resolution and noise on the spatial coherence of the source and the aperture in the imaging system are discussed and demonstrated by using numerical simulations.The results show that an incoherent source and a large aperture will lead to a good image quality and small noise.

  8. High-resolution imaging using endoscopic holography

    Science.gov (United States)

    Bjelkhagen, Hans I.

    1990-08-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help to their control. 1.

  9. Holographic high-resolution endoscopic image recording

    Science.gov (United States)

    Bjelkhagen, Hans I.

    1991-03-01

    Endoscopic holography or endoholography combines the features of endoscopy and holography. The purpose of endoholographic imaging is to provide the physician with a unique means of extending diagnosis by providing a life-like record of tissue. Endoholographic recording will provide means for microscopic examination of tissue and in some cases may obviate the need to excise specimens for biopsy. In this method holograms which have the unique properties of three-dimensionality large focal depth and high resolution are made with a newly designed endoscope. The endoscope uses a single-mode optical fiber for illumination and single-beam reflection holograms are recorded in close contact with the tissue at the distal end of the endoscope. The holograms are viewed under a microscope. By using the proper combinations of dyes for staining specific tissue types with various wavelengths of laser illumination increased contrast on the cellular level can be obtained. Using dyes such as rose bengal in combination with the 514. 5 nm line of an argon ion laser and trypan blue or methylene blue with the 647. 1 nm line of a krypton ion laser holograms of the stained colon of a dog showed the architecture of the colon''s columnar epithelial cells. It is hoped through chronological study using this method in-vivo an increased understanding of the etiology and pathology of diseases such as Crohn''s diseases colitis proctitis and several different forms of cancer will help

  10. Remote Sensing Image Resolution Enlargement Algorithm Based on Wavelet Transformation

    Directory of Open Access Journals (Sweden)

    Samiul Azam

    2014-05-01

    Full Text Available In this paper, we present a new image resolution enhancement algorithm based on cycle spinning and stationary wavelet subband padding. The proposed technique or algorithm uses stationary wavelet transformation (SWT to decompose the low resolution (LR image into frequency subbands. All these frequency subbands are interpolated using either bicubic or lanczos interpolation, and these interpolated subbands are put into inverse SWT process for generating intermediate high resolution (HR image. Finally, cycle spinning (CS is applied on this intermediate high resolution image for reducing blocking artifacts, followed by, traditional Laplacian sharpening filter is used to make the generated high resolution image sharper. This new technique has been tested on several satellite images. Experimental result shows that the proposed technique outperforms the conventional and the state-of-the-art techniques in terms of peak signal to noise ratio, root mean square error, entropy, as well as, visual perspective.

  11. Photo-magnetic Imaging: Resolving Optical Contrast at MRI resolution

    OpenAIRE

    Lin, Yuting; Gao, Hao; Thayer, David; Luk, Alex L.; Gulsen, Gultekin

    2013-01-01

    In this paper, we establish the mathematical framework of a novel imaging technique, namely Photo-magnetic Imaging (PMI). PMI uses laser to illuminate biological tissues and measure the induced temperature variations using magnetic resonance imaging (MRI). PMI overcomes the limitation of conventional optical imaging and allows imaging of optical contrast at MRI spatial resolution. The image reconstruction for PMI, using a finite element-based algorithm with iterative approach, is presented in...

  12. Milliarcsecond angular resolution of reddened stellar sources in the vicinity of the Galactic Center

    OpenAIRE

    Richichi, A.; Fors, O.; Mason, E.; Stegmaier, J; T.Chandrasekhar

    2008-01-01

    For the first time, the lunar occultation technique has been employed on a very large telescope in the near-IR with the aim of achieving systematically milliarcsecond resolution on stellar sources. We have demonstrated the burst mode of the ISAAC instrument, using a fast read-out on a small area of the detector to record many tens of seconds of data at a time on fields of few squared arcsec. We have used the opportunity to record a large number of LO events during a passage of the Moon close ...

  13. Resolution criteria in double-slit microscopic imaging experiments

    Science.gov (United States)

    You, Shangting; Kuang, Cuifang; Zhang, Baile

    2016-09-01

    Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit.

  14. Improving spatial resolution of confocal Raman microscopy by super-resolution image restoration.

    Science.gov (United States)

    Cui, Han; Zhao, Weiqian; Wang, Yun; Fan, Ying; Qiu, Lirong; Zhu, Ke

    2016-05-16

    A new super-resolution image restoration confocal Raman microscopy method (SRIR-RAMAN) is proposed for improving the spatial resolution of confocal Raman microscopy. This method can recover the lost high spatial frequency of the confocal Raman microscopy by using Poisson-MAP super-resolution imaging restoration, thereby improving the spatial resolution of confocal Raman microscopy and realizing its super-resolution imaging. Simulation analyses and experimental results indicate that the spatial resolution of SRIR-RAMAN can be improved by 65% to achieve 200 nm with the same confocal Raman microscopy system. This method can provide a new tool for high spatial resolution micro-probe structure detection in physical chemistry, materials science, biomedical science and other areas.

  15. Light energy matching method in high-resolution image reconstruction

    Institute of Scientific and Technical Information of China (English)

    Ling Wang(王凌); Zhihai Xu(徐之海); Huajun Feng(冯华君); Ping Zhang(张平)

    2003-01-01

    Many approaches for high-resolution image reconstruction have been proposed in some literatures. One ofthe most commonly ways is to reconstruct a high-resolution image from a number of rotated and translatedimages with low resolution. In this process, the exposure difference among original images will decreasethe quality of the reconstructed image. In order to remove the influence of the exposure difference, alight energy matching method is proposed in this paper. The theoretical analysis is illustrated in details.Experimental results show that the theoretical analysis is correct and the proposed method is valid.

  16. Infrared chemical imaging: Spatial resolution evaluation and super-resolution concept

    Energy Technology Data Exchange (ETDEWEB)

    Offroy, Marc [Laboratoire de Spectrochimie Infrarouge et Raman, LASIR, CNRS UMR 8516, Bat. C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France); Roggo, Yves [F. Hoffmann-La Roche A.G., Basel (Switzerland); Milanfar, Peyman [Multi-Dimensional Signal Processing Laboratory, Electrical Engineering Department, Baskin School of Engineering, University of California, 1156 High Street, Mailcode SOE2, Santa Cruz, CA 95064 (United States); Duponchel, Ludovic, E-mail: ludovic.duponchel@univ-lille1.fr [Laboratoire de Spectrochimie Infrarouge et Raman, LASIR, CNRS UMR 8516, Bat. C5, Universite des Sciences et Technologies de Lille, 59655 Villeneuve d' Ascq Cedex (France)

    2010-08-03

    Chemical imaging systems help to solve many challenges in various scientific fields. Able to deliver rapid spatial and chemical information, modern infrared spectrometers using Focal Plane Array detectors (FPA) are of great interest. Considering conventional infrared spectrometers with a single element detector, we can consider that the diffraction-limited spatial resolution is more or less equal to the wavelength of the light (i.e. 2.5-25 {mu}m). Unfortunately, the spatial resolution of FPA spectroscopic setup is even lower due to the detector pixel size. This becomes a real constraint when micron-sized samples are analysed. New chemometrics methods are thus of great interest to overcome such resolution drawback, while keeping our far-field infrared imaging spectrometers. The aim of the present work is to evaluate the super-resolution concept in order to increase the spatial resolution of infrared imaging spectrometers using FPA detectors. The main idea of super-resolution is the fusion of several low-resolution images of the same sample to obtain a higher-resolution image. Applying the super-resolution concept on a relatively low number of FPA acquisitions, it was possible to observe a 30% decrease in spatial resolution.

  17. Molecular outflows and hot molecular core in G24.78+0.08 at sub-arcsecond angular resolution

    CERN Document Server

    Beltran, M T; Zhang, Q; Galvan-Madrid, R; Beuther, H; Fallscheer, C; Neri, R; Codella, C

    2011-01-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims. We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods. We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 mm, respectively, of dust and of typical high-density and molecular outflow tracers with resolutions of <1". Complementary IRAM 30-m 12CO and 13CO observations were carried out to recover the short spacing information of the molecular outflows. Results. The millimeter continuum emission towards cores G24 A1 and A2 has been resolved into 3 and 2 cores, respectively, and named A1, A1b, A1c, A2, and A2b. All these cores are aligned in a southeast-northwest direction coincident with that of the molecular outflows detected i...

  18. Whole-animal imaging with high spatio-temporal resolution

    Science.gov (United States)

    Chhetri, Raghav; Amat, Fernando; Wan, Yinan; Höckendorf, Burkhard; Lemon, William C.; Keller, Philipp J.

    2016-03-01

    We developed isotropic multiview (IsoView) light-sheet microscopy in order to image fast cellular dynamics, such as cell movements in an entire developing embryo or neuronal activity throughput an entire brain or nervous system, with high resolution in all dimensions, high imaging speeds, good physical coverage and low photo-damage. To achieve high temporal resolution and high spatial resolution at the same time, IsoView microscopy rapidly images large specimens via simultaneous light-sheet illumination and fluorescence detection along four orthogonal directions. In a post-processing step, these four views are then combined by means of high-throughput multiview deconvolution to yield images with a system resolution of ≤ 450 nm in all three dimensions. Using IsoView microscopy, we performed whole-animal functional imaging of Drosophila embryos and larvae at a spatial resolution of 1.1-2.5 μm and at a temporal resolution of 2 Hz for up to 9 hours. We also performed whole-brain functional imaging in larval zebrafish and multicolor imaging of fast cellular dynamics across entire, gastrulating Drosophila embryos with isotropic, sub-cellular resolution. Compared with conventional (spatially anisotropic) light-sheet microscopy, IsoView microscopy improves spatial resolution at least sevenfold and decreases resolution anisotropy at least threefold. Compared with existing high-resolution light-sheet techniques, such as lattice lightsheet microscopy or diSPIM, IsoView microscopy effectively doubles the penetration depth and provides subsecond temporal resolution for specimens 400-fold larger than could previously be imaged.

  19. Time-resolved imaging of latent fingerprints with nanosecond resolution

    Science.gov (United States)

    Seah, L. K.; Dinish, U. S.; Ong, S. K.; Chao, Z. X.; Murukeshan, V. M.

    2004-07-01

    Imaging of latent fingerprints using time-resolved (TR) method offers a broader platform to eliminate the unwanted background emission. In this paper, a novel TR imaging technique is demonstrated and implemented, which facilitates the detection of latent fingerprints with nanosecond resolution. Simulated experiments were carried out with two overlapping fingerprints treated with two fluorescent powders having different lifetimes in nanosecond range. The dependence of the fluorescence emission intensity in nanosecond resolution of TR imaging is also revealed.

  20. HIGH-RESOLUTION IMAGING OF THE ATLBS REGIONS: THE RADIO SOURCE COUNTS

    International Nuclear Information System (INIS)

    The Australia Telescope Low-brightness Survey (ATLBS) regions have been mosaic imaged at a radio frequency of 1.4 GHz with 6'' angular resolution and 72 μJy beam–1 rms noise. The images (centered at R.A. 00h35m00s, decl. –67°00'00'' and R.A. 00h59m17s, decl. –67°00'00'', J2000 epoch) cover 8.42 deg2 sky area and have no artifacts or imaging errors above the image thermal noise. Multi-resolution radio and optical r-band images (made using the 4 m CTIO Blanco telescope) were used to recognize multi-component sources and prepare a source list; the detection threshold was 0.38 mJy in a low-resolution radio image made with beam FWHM of 50''. Radio source counts in the flux density range 0.4-8.7 mJy are estimated, with corrections applied for noise bias, effective area correction, and resolution bias. The resolution bias is mitigated using low-resolution radio images, while effects of source confusion are removed by using high-resolution images for identifying blended sources. Below 1 mJy the ATLBS counts are systematically lower than the previous estimates. Showing no evidence for an upturn down to 0.4 mJy, they do not require any changes in the radio source population down to the limit of the survey. The work suggests that automated image analysis for counts may be dependent on the ability of the imaging to reproduce connecting emission with low surface brightness and on the ability of the algorithm to recognize sources, which may require that source finding algorithms effectively work with multi-resolution and multi-wavelength data. The work underscores the importance of using source lists—as opposed to component lists—and correcting for the noise bias in order to precisely estimate counts close to the image noise and determine the upturn at sub-mJy flux density.

  1. Nanoprobes for super-resolution fluorescence imaging at the nanoscale

    Institute of Scientific and Technical Information of China (English)

    HOU ShangGuo; LIANG Le; DENG SuHui; CHEN JianFang; HUANG Qing; CHENG Ya; FAN ChunHai

    2014-01-01

    Compared with other imaging techniques,fluorescence microscopy has become an essential tool to study cell biology due to its high compatibility with living cells.Owing to the resolution limit set by the diffraction of light,fluorescence microscopy could not resolve the nanostructures in the range of〈200 nm.Recently,many techniques have been emerged to overcome the diffraction barrier,providing nanometer spatial resolution.In the course of development,the progress in fluorescent probes has helped to promote the development of the high-resolution fluorescence nanoscopy.Here,we describe the contributions of the fluorescent probes to far-field super resolution imaging,focusing on concepts of the existing super-resolution nanoscopy based on the photophysics of fluorescent nanoprobes,like photoswitching,bleaching and blinking.Fluorescent probe technology is crucial in the design and implementation of super-resolution imaging methods.

  2. Multiframe Blind Super Resolution Imaging Based on Blind Deconvolution

    Institute of Scientific and Technical Information of China (English)

    元伟; 张立毅

    2016-01-01

    As an ill-posed problem, multiframe blind super resolution imaging recovers a high resolution image from a group of low resolution images with some degradations when the information of blur kernel is limited. Note that the quality of the recovered image is influenced more by the accuracy of blur estimation than an advanced regularization. We study the traditional model of the multiframe super resolution and modify it for blind deblurring. Based on the analysis, we proposed two algorithms. The first one is based on the total variation blind deconvolution algorithm and formulated as a functional for optimization with the regularization of blur. Based on the alternating minimization and the gradient descent algorithm, the high resolution image and the unknown blur kernel are esti-mated iteratively. By using the median shift and add operator, the second algorithm is more robust to the outlier influence. The MSAA initialization simplifies the interpolation process to reconstruct the blurred high resolution image for blind deblurring and improves the accuracy of blind super resolution imaging. The experimental results demonstrate the superiority and accuracy of our novel algorithms.

  3. Super-resolution Restoration of Remote-sensing Images

    Institute of Scientific and Technical Information of China (English)

    LIU Yang-yang; JIN Wei-qi; SU Bing-hua; CHEN Hua; ZHANG Nan

    2006-01-01

    A novel image restoration scheme, which is super-resolution image restoration algorithm Poisson-maximum-afterword-probability based on Markvo constraint (MPMAP) combined with evaluating image detail parameter D, has been proposed. The advantage of super-resolution algorithm MPMAP incorporated with parameter D lies in the fact that super-resolution algorithm MPMAP model is discrete, which is in accordance with remote-sensing imaging model, and the algorithm MPMAP is proved applicable to linear and non-linear imaging models with a unique solution when noise is not severe. According to simulation experiments for practical images, super-resolution algorithm MPMAP can retain image details better than most of traditional restoration methods; at the same time, the proposed parameter D can help to identify real point spread function (PSF) value of degradation process. Processing result of practical remote-sensing images by MPMAP combined with parameter D are given, it illustrates that MPMAP restoration scheme combined PSF estimation has a better restoration result than that of Photoshop processing, based on the same original images. It is proved that the proposed scheme is helpful to offset the lack of resolution of the original remote-sensing images and has its extensive application foreground.

  4. Super-resolution Image Created from a Sequence of Images with Application of Character Recognition

    Directory of Open Access Journals (Sweden)

    Leandro Luiz de Almeida

    2013-12-01

    Full Text Available Super-resolution techniques allow combine multiple images of the same scene to obtain an image with increased geometric and radiometric resolution, called super-resolution image. In this image are enhanced features allowing to recover important details and information. The objective of this work is to develop efficient algorithm, robust and automated fusion image frames to obtain a super-resolution image. Image registration is a fundamental step in combining several images that make up the scene. Our research is based on the determination and extraction of characteristics defined by the SIFT and RANSAC algorithms for automatic image registration. We use images containing characters and perform recognition of these characters to validate and show the effectiveness of our proposed method. The distinction of this work is the way to get the matching and merging of images because it occurs dynamically between elements common images that are stored in a dynamic matrix.

  5. HIGH ANGULAR RESOLUTION MULTI-LINE STUDY OF HH 1 AND 2

    Energy Technology Data Exchange (ETDEWEB)

    Raga, A. C.; Castellanos-Ramírez, A. [Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Ap. 70-543, 04510 D.F., México (Mexico); Reipurth, Bo; Chiang, Hsin-Fang [Institute for Astronomy, University of Hawaii at Manoa, Hilo, HI 96720 (United States); Bally, J., E-mail: raga@nucleares.unam.mx [Center for Astrophysics and Space Astronomy, University of Colorado, UCB 389, Boulder, CO 80309 (United States)

    2015-10-15

    We present new Hubble Space Telescope (HST) narrow band images of the bright Herbig–Haro (HH) objects HH 1 and 2 in the light of the Hα, Hβ, [O i] 6300, [O ii] 3726+28, [O iii] 5007 and [S ii] 6716+30 emission lines. The resulting emission and line ratio maps give an improved picture of the physical structure of these HH objects, showing the presence of spatially limited, high excitation/ionization ridges. We find that HH 1 has a morphology that could be interpreted in terms of a single, asymmetric bow shock, and that many of the clumps of HH 2 fall in two bow-shaped structures of different excitations. We also construct two-line ratio plots showing clear trends, which are much simpler than the highly complex spatial distributions of the emission, and are therefore interesting for testing shock models of HH objects (we only present a comparison with previously published, steady plane-parallel shock models). We have also used the temperature-sensitive [O i]/[S ii] line ratio to evaluate the temperature range and to obtain temperature maps of HH 1 and 2. We find that this line ratio picks out emitting regions with temperatures ≈10{sup 4} K, except along the leading edges of the HH 1 and 2 bow shocks (in which temperatures of ∼3 → 5 × 10{sup 4} K are obtained)

  6. Image Resolution and Contrast Enhancement of Satellite Geographical Images with Removal of Noise using Wavelet Transforms

    OpenAIRE

    Khairnar, Prajakta P.; Manjare, C. A.

    2014-01-01

    In this paper the technique for resolution and contrast enhancement of satellite geographical images based on discrete wavelet transform (DWT), stationary wavelet transform (SWT) and singular value decomposition (SVD) has been proposed. In this, the noise is added in the input low resolution and low contrast image. The median filter is used remove noise from the input image. This low resolution, low contrast image without noise is decomposed into four sub-bands by using DWT and SWT. The resol...

  7. Super-resolution photoacoustic imaging of single gold nanoparticles

    Science.gov (United States)

    Lee, Seunghyun; Kwon, Owoong; Jeon, Mansik; Song, Jaejung; Jo, Minguk; Kim, Sungjee; Son, Junwoo; Kim, Yunseok; Kim, Chulhong

    2016-03-01

    Photoacoustic imaging (PAI) is an emerging hybrid imaging modality that can provide a strong optical absorption contrast using the photoacoustic (PA) effect, and breaks through the fundamental imaging depth limit of existing optical microscopy such as optical coherence tomography (OCT), confocal or two-photon microscopy. In PAI, a short-pulsed laser is illuminated to the tissue, and the PA waves are generated by thermoelastic expansion. Despite the high lateral resolution of optical-resolution photoacoustic microscopy (OR-PAM) thanks to the tight optical focus, the lateral resolution of OR-PAM is limited to the optical diffraction limit, which is approximately a half of the excitation wavelength. Here, we demonstrate a new super-resolution photoacoustic microscopy (SR-PAM) system by breaking the optical diffraction limit. The conventional microscopes with nanoscale resolutions such as a scanning electron microscope (SEM) and transmission electron microscope (TEM) are typically used to image the structures of nanomaterials, but these systems should work in a high vacuum environment and cannot provide the optical properties of the materials. Our newly developed SR-PAM system provides the optical properties with a nanoscale resolution in a normal atmosphere. We have photoacoustically imaged single gold nanoparticles with an average size of 80 nm in diameter and shown their PA expansion properties individually. The lateral resolution of this system was approximately 20 nm. Therefore, this tool will provide an unprecedented optical absorption property with an accurate nanoscale resolution and greatly impact on materials science and nanotechnology field.

  8. High resolution multiplexed functional imaging in live embyros (Conference Presentation)

    Science.gov (United States)

    Xu, Dongli; Peng, Leilei

    2016-03-01

    Optical projection tomography (OPT) creates isotropic 3D imaging of tissue. Two approaches exist today: Wide-field OPT illuminates the entire sample and acquires projection images with a camera; Scanning-laser optical tomography (SLOT) generates the projection with a moving laser beam and point detector. SLOT has superior light collecting efficiency than wide-field optical tomography, making it ideal for tissue fluorescence imaging. Regardless the approach, traditional OPT has to compromise between the resolution and the depth of view. In traditional SLOT, the focused Gaussian beam diverges quickly from the focused plane, making it impossible to achieve high resolution imaging through a large volume specimen. We report using Bessel beam instead of Gaussian beam to perform SLOT. By illuminating samples with a narrow Bessel beam throughout an extended depth, high-resolution projection images can be measured in large volume. Under Bessel illumination, the projection image contains signal from annular-rings of the Bessel beam. Traditional inverse Radon transform of these projections will result in ringing artifacts in reconstructed imaging. Thus a modified 3D filtered back projection algorithm is developed to perform tomography reconstructing of Bessel-illuminated projection images. The resulting 3D imaging is free of artifact and achieved cellular resolution in extended sample volume. The system is applied to in-vivo imaging of transgenic Zebrafish embryos. Results prove Bessel SLOT a promising imaging method in development biology research.

  9. SUPER RESOLUTION FOR EGYPTSAT-1 IMAGES WITH ERRATIC SHIFT

    Directory of Open Access Journals (Sweden)

    A. H. Nasr

    2014-01-01

    Full Text Available The key point of the Super-Resolution (SR process is the accurate registration of the low resolution images, i.e., accurate measuring of the fixed shift between them, to obtain high resolution image. Due to certain malfunction, some Egyptsat-1 images have inconsistent sub-pixel shift. Therefore, in this study we propose a methodology to use this kind of shift for reconstructing a SR image of Egyptsat-1 from its low resolution bands. It is a trade-off between the capability of catching spatial details and the sensitivity to the erratic shift existed along the image. Firstly, this inconsistent shift between the bands is transformed into reliable shift. Then a SR method based on image fusion scheme with multi-resolution decomposition is performed. The fusion process is conducted in steerable wavelet domain using normalized convolution technique. It allows the recognition of objects with size approaching its limiting spatial resolution. Results show that the proposed methods make significant spatial resolution improvements from 7.8 to 4 m. Different quantitative measures of the proposed methodology were assessed and tested with some implemented commonly used SR methods. These methods are; nonparametric bayesian, POCS, iterative-interpolation, robust and iterated back projection. The visual and quantitative evaluations verify the usefulness and effectiveness of the proposed methodology.

  10. Influence of imaging resolution on color fidelity in digital archiving.

    Science.gov (United States)

    Zhang, Pengchang; Toque, Jay Arre; Ide-Ektessabi, Ari

    2015-11-01

    Color fidelity is of paramount importance in digital archiving. In this paper, the relationship between color fidelity and imaging resolution was explored by calculating the color difference of an IT8.7/2 color chart with a CIELAB color difference formula for scanning and simulation images. Microscopic spatial sampling was used in selecting the image pixels for the calculations to highlight the loss of color information. A ratio, called the relative imaging definition (RID), was defined to express the correlation between image resolution and color fidelity. The results show that in order for color differences to remain unrecognizable, the imaging resolution should be at least 10 times higher than the physical dimension of the smallest feature in the object being studied.

  11. Heisenberg scaling of imaging resolution by coherent enhancement

    CERN Document Server

    McConnell, Robert; Yoder, Theodore J; Bruzewicz, Colin D; Chuang, Isaac L; Chiaverini, John; Sage, Jeremy M

    2016-01-01

    Classical imaging works by scattering photons from an object to be imaged, and achieves resolution scaling as $1/\\sqrt{t}$, with $t$ the imaging time. By contrast, the laws of quantum mechanics allow one to utilize quantum coherence to obtain imaging resolution that can scale as quickly as $1/t$ -- the so-called "Heisenberg limit." However, ambiguities in the obtained signal often preclude taking full advantage of this quantum enhancement, while imaging techniques designed to be unambiguous often lose this optimal Heisenberg scaling. Here, we demonstrate an imaging technique which combines unambiguous detection of the target with Heisenberg scaling of the resolution. We also demonstrate a binary search algorithm which can efficiently locate a coherent target using the technique, resolving a target trapped ion to within 3% of the $1/e^2$ diameter of the excitation beam.

  12. Bendable X-ray Optics for High Resolution Imaging

    Science.gov (United States)

    Gubarev, M.; Ramsey, B.; Kilaru, K.; Atkins, C.; Broadway, D.

    2014-01-01

    Current state-of the-art for x-ray optics fabrication calls for either the polishing of massive substrates into high-angular-resolution mirrors or the replication of thin, lower-resolution, mirrors from perfectly figured mandrels. Future X-ray Missions will require a change in this optics fabrication paradigm in order to achieve sub-arcsecond resolution in light-weight optics. One possible approach to this is to start with perfectly flat, light-weight surface, bend it into a perfect cone, form the desired mirror figure by material deposition, and insert the resulting mirror into a telescope structure. Such an approach is currently being investigated at MSFC, and a status report will be presented detailing the results of finite element analyses, bending tests and differential deposition experiments.

  13. Application of Super-Resolution Image Reconstruction to Digital Holography

    Directory of Open Access Journals (Sweden)

    Zhang Shuqun

    2006-01-01

    Full Text Available We describe a new application of super-resolution image reconstruction to digital holography which is a technique for three-dimensional information recording and reconstruction. Digital holography has suffered from the low resolution of CCD sensors, which significantly limits the size of objects that can be recorded. The existing solution to this problem is to use optics to bandlimit the object to be recorded, which can cause the loss of details. Here super-resolution image reconstruction is proposed to be applied in enhancing the spatial resolution of digital holograms. By introducing a global camera translation before sampling, a high-resolution hologram can be reconstructed from a set of undersampled hologram images. This permits the recording of larger objects and reduces the distance between the object and the hologram. Practical results from real and simulated holograms are presented to demonstrate the feasibility of the proposed technique.

  14. Super-resolved imaging with ultimate time resolution

    CERN Document Server

    Ashida, Yuto

    2015-01-01

    Precisely and accurately locating point objects is a long-standing common thread in science. Super-resolved imaging of single molecules has revolutionized our view of quasi-static nanostructures $\\it{in-vivo}$. A wide-field approach based on localizing individual fluorophores has emerged as a versatile method to surpass the standard resolution limit. In those techniques, the super-resolution is realized by sparse photoactivation and localization together with the statistical analysis based on point spread functions. Nevertheless, the slow temporal resolution of super-resolved imaging severely restricts the utility to the study of live-cell phenomena. Clearly, a major breakthrough to observe fast, nanoscale dynamics needs to be made. Here we present a super-resolved imaging method that achieves the theoretical-limit time resolution. By invoking information theory, we can achieve the robust localization of overlapped light emitters at an order of magnitude faster speed than the conventional super-resolution mic...

  15. The complex evolutionary paths of local infrared bright galaxies: a high angular resolution mid-infrared view

    CERN Document Server

    Alonso-Herrero, A; Roche, P F; Hernan-Caballero, A; Aretxaga, I; Martinez-Paredes, M; Almeida, C Ramos; Pereira-Santaella, M; Diaz-Santos, T; Levenson, N A; Packham, C; Colina, L; Esquej, P; Gonzalez-Martin, O; Ichikawa, K; Imanishi, M; Espinosa, J M Rodriguez; Telesco, C

    2016-01-01

    We investigate the evolutionary connection between local IR-bright galaxies ($\\log L_{\\rm IR}\\ge 11.4\\,L_\\odot$) and quasars. We use high angular resolution ($\\sim$ 0.3-0.4 arcsec $\\sim$ few hundred parsecs) $8-13\\,\\mu$m ground-based spectroscopy to disentangle the AGN mid-IR properties from those of star formation. The comparison between the nuclear $11.3\\,\\mu$m PAH feature emission and that measured with Spitzer/IRS indicates that the star formation is extended over a few kpc in the IR-bright galaxies. The AGN contribution to the total IR luminosity of IR-bright galaxies is lower than in quasars. Although the dust distribution is predicted to change as IR-bright galaxies evolve to IR-bright quasars and then to optical quasars, we show that the AGN mid-IR emission of all the quasars in our sample is not significantly different. In contrast, the nuclear emission of IR-bright galaxies with low AGN contributions appears more heavily embedded in dust although there is no clear trend with the interaction stage or...

  16. Virtual microscope interface to high resolution histological images

    OpenAIRE

    Feit, Josef; Matyska, Luděk; Ulman, Vladimír; HEJTMÁNEK, Lukáš; Jedličková, Hana; Ježová, Marta; Moulis, Mojmír; Feitová, Věra

    2008-01-01

    The Hypertext atlas of Dermatopathology, the Atlas of Fetal and Neonatal Pathology and Hypertext atlas of Pathology (this one in Czech only) are available at . These atlases offer many clinical, macroscopic and microscopic images, together with short introductory texts. Most of the images are annotated and arrows pointing to the important parts of the image can be activated. The Virtual Microscope interface is used for the access to the histological images obtained in high resolution using au...

  17. High Resolution, Range/Range-Rate Imager Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Visidyne proposes to develop a design for a small, lightweight, high resolution, in x, y, and z Doppler imager to assist in the guidance, navigation and control...

  18. Left-handed metamaterial coatings for subwavelength-resolution imaging.

    Science.gov (United States)

    Zapata-Rodríguez, Carlos J; Pastor, David; Martínez, Luis E; Miret, Juan J

    2012-09-01

    We report on a procedure to improve the resolution of far-field imaging by using a neighboring high-index medium that is coated with a left-handed metamaterial. The resulting plot can also exhibit an enhanced transmission by considering proper conditions to retract backscattering. Based on negative refraction, geometrical aberrations are considered in detail since they may cause a great impact in this sort of diffraction-unlimited imaging by reducing its resolution power. We employ a standard aberration analysis to refine the asymmetric configuration of metamaterial superlenses. We demonstrate that low-order centrosymmetric aberrations can be fully corrected for a given object plane. For subwavelength-resolution imaging, however, high-order aberrations become of relevance, which may be balanced with defocus. Not only the point spread function but also numerical simulations based on the finite-element method support our theoretical analysis, and subwavelength resolution is verified in the image plane.

  19. Land Cover Semantic Annotation Derived from High Resolution SAR Images

    OpenAIRE

    Dumitru, Corneliu Octavian; Schwarz, Gottfried; Datcu, Mihai

    2016-01-01

    Users of remote sensing images analyzing land cover characteristics are very much interested in classification schemes that define a consistent set of target categories. Up to now, a number of established classification schemes are mainly being used by interpreters of medium-resolution optical satellite image focusing on large-scale land cover. In contrast, we concentrate in this publication on the definition of a new classification scheme for high-resolution synthetic aperture radar (S...

  20. Image Resolution in the Digital Era: Notion and Clinical Implications

    OpenAIRE

    Vahid Rakhshan

    2014-01-01

    Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs.

  1. Angular resolution measurements at SPring-8 of a hard X-ray optic for the New Hard X-ray Mission

    CERN Document Server

    Spiga, D; Furuzawa, A; Basso, S; Binda, R; Borghi, G; Cotroneo, V; Grisoni, G; Kunieda, H; Marioni, F; Matsumoto, H; Mori, H; Miyazawa, T; Negri, B; Orlandi, A; Pareschi, G; Salmaso, B; Tagliaferri, G; Uesugi, K; Valsecchi, G; Vernani, D

    2015-01-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with on- ground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aime...

  2. Analyzing angular distributions for two-step dissociation mechanisms in velocity map imaging.

    Science.gov (United States)

    Straus, Daniel B; Butler, Lynne M; Alligood, Bridget W; Butler, Laurie J

    2013-08-15

    Increasingly, velocity map imaging is becoming the method of choice to study photoinduced molecular dissociation processes. This paper introduces an algorithm to analyze the measured net speed, P(vnet), and angular, β(vnet), distributions of the products from a two-step dissociation mechanism, where the first step but not the second is induced by absorption of linearly polarized laser light. Typically, this might be the photodissociation of a C-X bond (X = halogen or other atom) to produce an atom and a momentum-matched radical that has enough internal energy to subsequently dissociate (without the absorption of an additional photon). It is this second step, the dissociation of the unstable radicals, that one wishes to study, but the measured net velocity of the final products is the vector sum of the velocity imparted to the radical in the primary photodissociation (which is determined by taking data on the momentum-matched atomic cophotofragment) and the additional velocity vector imparted in the subsequent dissociation of the unstable radical. The algorithm allows one to determine, from the forward-convolution fitting of the net velocity distribution, the distribution of velocity vectors imparted in the second step of the mechanism. One can thus deduce the secondary velocity distribution, characterized by a speed distribution P(v1,2°) and an angular distribution I(θ2°), where θ2° is the angle between the dissociating radical's velocity vector and the additional velocity vector imparted to the product detected from the subsequent dissociation of the radical. PMID:23464815

  3. High resolution multimodal clinical ophthalmic imaging system

    OpenAIRE

    Mujat, Mircea; Ferguson, R. Daniel; Patel, Ankit H.; Iftimia, Nicusor; Lue, Niyom; Hammer, Daniel X.

    2010-01-01

    We developed a multimodal adaptive optics (AO) retinal imager which is the first to combine high performance AO-corrected scanning laser ophthalmoscopy (SLO) and swept source Fourier domain optical coherence tomography (SSOCT) imaging modes in a single compact clinical prototype platform. Such systems are becoming ever more essential to vision research and are expected to prove their clinical value for diagnosis of retinal diseases, including glaucoma, diabetic retinopathy (DR), age-related m...

  4. Reference-free method for forming a three-dimensional image and determining the angular velocity of a remote object

    NARCIS (Netherlands)

    Mandrosov, V. I.

    2012-01-01

    We propose a reference-free method for forming a three-dimensional image and for determining the angular velocity of a remote nonplanar object. The method is based on probing an object by laser radiation with a coherence length that is smaller or larger than the size of the object and on the use of

  5. High spatial resolution diffusion tensor imaging and its applications

    CERN Document Server

    Wang, J J

    2002-01-01

    Introduction Magnetic Resonance Imaging is at present the only imaging technique available to measure diffusion of water and metabolites in humans. It provides vital insights to brain connectivity and has proved to be an important tool in diagnosis and therapy planning in many neurological diseases such as brain tumour, ischaemia and multiple sclerosis. This project focuses on the development of a high resolution diffusion tensor imaging technique. In this thesis, the basic theory of diffusion tensor MR Imaging is presented. The technical challenges encountered during development of these techniques will be discussed, with proposed solutions. New sequences with high spatial resolution have been developed and the results are compared with the standard technique more commonly used. Overview The project aims at the development of diffusion tensor imaging techniques with a high spatial resolution. Chapter 2 will describe the basic physics of MRI, the phenomenon of diffusion and the measurement of diffusion by MRI...

  6. Facial Image Super Resolution Using Weighted Patch Pairs

    Directory of Open Access Journals (Sweden)

    Payman Moallem

    2013-03-01

    Full Text Available A challenging field in image processing and computer graphics is to have higher frequency details by super resolving facial images. Unlike similar papers in this field, this paper introduces a practical face hallucinating approach with higher quality output images. The image reconstruction was based on a set of high and low resolution image pairs. Each image is divided into defined patches with overlapped regions. A patch from a defined location is removed from the low resolution (LR input image and is compared with the LR patches of the training images with the same location. Each defined LR patch has a defined high resolution (HR patch. Based on the Euclidean distance comparison, each patch of every single image in the training images database receives a specific weight. This weight is transferred to its relevant HR patch identically. The sum of the gained weights for one specific location of a patch is equal to unity. The HR output image is constructed by integrating the HR hallucinated patches.

  7. High-resolution multi-band imaging for validation and characterization of small Kepler planets

    Energy Technology Data Exchange (ETDEWEB)

    Everett, Mark E.; Silva, David R. [National Optical Astronomy Observatory, 950 North Cherry Avenue Tucson, AZ 85719 (United States); Barclay, Thomas; Howell, Steve B. [NASA Ames Research Center, Moffett Field, CA 94035 (United States); Ciardi, David R. [NASA Exoplanet Science Institute, 770 South Wilson Avenue, Pasadena, CA 91125 (United States); Horch, Elliott P. [Department of Physics, Southern Connecticut State University, 501 Crescent Street, New Haven, CT 06515 (United States); Crepp, Justin R. [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States)

    2015-02-01

    High-resolution ground-based optical speckle and near-infrared adaptive optics images are taken to search for stars in close angular proximity to host stars of candidate planets identified by the NASA Kepler Mission. Neighboring stars are a potential source of false positive signals. These stars also blend into Kepler light curves, affecting estimated planet properties, and are important for an understanding of planets in multiple star systems. Deep images with high angular resolution help to validate candidate planets by excluding potential background eclipsing binaries as the source of the transit signals. A study of 18 Kepler Object of Interest stars hosting a total of 28 candidate and validated planets is presented. Validation levels are determined for 18 planets against the likelihood of a false positive from a background eclipsing binary. Most of these are validated at the 99% level or higher, including five newly validated planets in two systems: Kepler-430 and Kepler-431. The stellar properties of the candidate host stars are determined by supplementing existing literature values with new spectroscopic characterizations. Close neighbors of seven of these stars are examined using multi-wavelength photometry to determine their nature and influence on the candidate planet properties. Most of the close neighbors appear to be gravitationally bound secondaries, while a few are best explained as closely co-aligned field stars. Revised planet properties are derived for each candidate and validated planet, including cases where the close neighbors are the potential host stars.

  8. Synthetic aperture radar images with composite azimuth resolution

    Energy Technology Data Exchange (ETDEWEB)

    Bielek, Timothy P; Bickel, Douglas L

    2015-03-31

    A synthetic aperture radar (SAR) image is produced by using all phase histories of a set of phase histories to produce a first pixel array having a first azimuth resolution, and using less than all phase histories of the set to produce a second pixel array having a second azimuth resolution that is coarser than the first azimuth resolution. The first and second pixel arrays are combined to produce a third pixel array defining a desired SAR image that shows distinct shadows of moving objects while preserving detail in stationary background clutter.

  9. Spatial Resolution Characterization for AWiFS Multispectral Images

    Science.gov (United States)

    Blonski, Slawomir; Ryan, Robert E.; Pagnutti, Mary; Stanley, Thomas

    2007-01-01

    This viewgraph presentation describes the spatial resolution of the AWiFS multispectral images characterized by an estimation of the Modulation Transfer Function (MTF) at Nyquist frequency. The contents include: 1) MTF Analysis; 2) Target Analysis; 3) "Pulse Target"; 4) "Pulse" Method; 5) Target Images; 6) Bridge Profiles; 7) MTF Calculation; 8) MTF Results; and 9) Results Summary.

  10. Image Super-Resolution Using Deep Convolutional Networks.

    Science.gov (United States)

    Dong, Chao; Loy, Chen Change; He, Kaiming; Tang, Xiaoou

    2016-02-01

    We propose a deep learning method for single image super-resolution (SR). Our method directly learns an end-to-end mapping between the low/high-resolution images. The mapping is represented as a deep convolutional neural network (CNN) that takes the low-resolution image as the input and outputs the high-resolution one. We further show that traditional sparse-coding-based SR methods can also be viewed as a deep convolutional network. But unlike traditional methods that handle each component separately, our method jointly optimizes all layers. Our deep CNN has a lightweight structure, yet demonstrates state-of-the-art restoration quality, and achieves fast speed for practical on-line usage. We explore different network structures and parameter settings to achieve trade-offs between performance and speed. Moreover, we extend our network to cope with three color channels simultaneously, and show better overall reconstruction quality. PMID:26761735

  11. Image Super-Resolution Using Deep Convolutional Networks.

    Science.gov (United States)

    Dong, Chao; Loy, Chen Change; He, Kaiming; Tang, Xiaoou

    2016-02-01

    We propose a deep learning method for single image super-resolution (SR). Our method directly learns an end-to-end mapping between the low/high-resolution images. The mapping is represented as a deep convolutional neural network (CNN) that takes the low-resolution image as the input and outputs the high-resolution one. We further show that traditional sparse-coding-based SR methods can also be viewed as a deep convolutional network. But unlike traditional methods that handle each component separately, our method jointly optimizes all layers. Our deep CNN has a lightweight structure, yet demonstrates state-of-the-art restoration quality, and achieves fast speed for practical on-line usage. We explore different network structures and parameter settings to achieve trade-offs between performance and speed. Moreover, we extend our network to cope with three color channels simultaneously, and show better overall reconstruction quality.

  12. Resolution criteria in double-slit microscopic imaging experiments

    Science.gov (United States)

    You, Shangting; Kuang, Cuifang; Zhang, Baile

    2016-01-01

    Double-slit imaging is widely used for verifying the resolution of high-resolution and super-resolution microscopies. However, due to the fabrication limits, the slit width is generally non-negligible, which can affect the claimed resolution. In this paper we theoretically calculate the electromagnetic field distribution inside and near the metallic double slit using waveguide mode expansion method, and acquire the far-field image by vectorial Fourier optics. We find that the slit width has minimal influence when the illuminating light is polarized parallel to the slits. In this case, the claimed resolution should be based on the center-to-center distance of the double-slit. PMID:27640808

  13. Neutron radiography and its image resolutions

    International Nuclear Information System (INIS)

    Neutron radiography (NR) is widely applied especially for non-destructive inspection of industrial products. An outline of NR technique is given in this report with few examples of industrial applications. The quality of a NR image depends on many factors. The values of L, D, and L/D are main factors to define a geometrical unsharpness of NR images. A device for accurate measurements of those parameters is proposed and fabricated. Degree of confidence is estimated for measurements of those parameters in detail. Values of L, D, and L/D are measured for our NR facilities with different geometrical conditions by use of the device and the values are compared to the designed values. The quality of the NR image also depends on an inherent unsharpness of its imaging device. The inherent unsharpness is measured as an edge spread function (ESF) and a modulation transfer function (MTF) is derived from the ESF with a technique of the discrete fast Fourier transform (DFFT). Results are compared to theoretically calculated MTF. (author)

  14. Compact and mobile high resolution PET brain imager

    Science.gov (United States)

    Majewski, Stanislaw; Proffitt, James

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  15. Automatic Matching of High Resolution Satellite Images Based on RFM

    Directory of Open Access Journals (Sweden)

    JI Shunping

    2016-02-01

    Full Text Available A matching method for high resolution satellite images based on RFM is presented.Firstly,the RFM parameters are used to predict the initial parallax of corresponding points and the prediction accuracy is analyzed.Secondly,the approximate epipolar equation is constructed based on projection tracking and its accuracy is analyzed.Thirdly,approximate 1D image matching is executed on pyramid images and least square matching on base images.At last RANSAC is imbedded to eliminate mis-matching points and matching results are obtained.Test results verified the method more robust and with higher matching rate,compared to 2D gray correlation method and the popular SIFT matching method,and the method preferably solved the question of high resolution satellite image matching with different stereo model,different time and large rotation images.

  16. High spectral resolution airborne short wave infrared hyperspectral imager

    Science.gov (United States)

    Wei, Liqing; Yuan, Liyin; Wang, Yueming; Zhuang, Xiaoqiong

    2016-05-01

    Short Wave InfraRed(SWIR) spectral imager is good at detecting difference between materials and penetrating fog and mist. High spectral resolution SWIR hyperspectral imager plays a key role in developing earth observing technology. Hyperspectral data cube can help band selections that is very important for multispectral imager design. Up to now, the spectral resolution of many SWIR hyperspectral imagers is about 10nm. A high sensitivity airborne SWIR hyperspectral imager with narrower spectral band will be presented. The system consists of TMA telescope, slit, spectrometer with planar blazed grating and high sensitivity MCT FPA. The spectral sampling interval is about 3nm. The IFOV is 0.5mrad. To eliminate the influence of the thermal background, a cold shield is designed in the dewar. The pixel number of spatial dimension is 640. Performance measurement in laboratory and image analysis for flight test will also be presented.

  17. Angular resolution measurements at SPring-8 of a hard x-ray optic for the New Hard X-ray Mission

    Science.gov (United States)

    Spiga, D.; Raimondi, L.; Furuzawa, A.; Basso, S.; Binda, R.; Borghi, G.; Cotroneo, V.; Grisoni, G.; Kunieda, H.; Marioni, F.; Matsumoto, H.; Mori, H.; Miyazawa, T.; Negri, B.; Orlandi, A.; Pareschi, G.; Salmaso, B.; Tagliaferri, G.; Uesugi, K.; Valsecchi, G.; Vernani, D.

    2011-09-01

    The realization of X-ray telescopes with imaging capabilities in the hard (> 10 keV) X-ray band requires the adoption of optics with shallow (=10 m shall be produced and tested. Full-illumination tests of such mirrors are usually performed with onground X-ray facilities, aimed at measuring their effective area and the angular resolution; however, they in general suffer from effects of the finite distance of the X-ray source, e.g. a loss of effective area for double reflection. These effects increase with the focal length of the mirror under test; hence a "partial" full-illumination measurement might not be fully representative of the in-flight performances. Indeed, a pencil beam test can be adopted to overcome this shortcoming, because a sector at a time is exposed to the X-ray flux, and the compensation of the beam divergence is achieved by tilting the optic. In this work we present the result of a hard X-ray test campaign performed at the BL20B2 beamline of the SPring-8 synchrotron radiation facility, aimed at characterizing the Point Spread Function (PSF) of a multilayer-coated Wolter-I mirror shell manufactured by Nickel electroforming. The mirror shell is a demonstrator for the NHXM hard X-ray imaging telescope (0.3 - 80 keV), with a predicted HEW (Half Energy Width) close to 20 arcsec. We show some reconstructed PSFs at monochromatic X-ray energies of 15 to 63 keV, and compare them with the PSFs computed from post-campaign metrology data, self-consistently treating profile and roughness data by means of a method based on the Fresnel diffraction theory. The modeling matches the measured PSFs accurately.

  18. Thin monolithic glass shells for future high angular resolution and large collecting area x-ray telescope

    Science.gov (United States)

    Civitani, M. M.; Citterio, O.; Ghigo, M.; Mattaini, E.; Pareschi, G.; Parodi, G.

    2013-09-01

    One of the most difficult requests to be accomplished from the technological point of view for next generation x-ray telescopes is to combine high angular resolution and effective area. A significant increase of effective area can be reached with high precision but at the same time thin (2-3 mm thickness for mirror diameters of 30-110 cm) glass mirror shells. In the last few years the Brera Observatory has lead a development program for realizing this kind of monolithic thin glass shell. The fused silica has been chosen as shell substrate due to its thermal and mechanical properties. To bring the mirror shells to the needed accuracy, we have adopted a deterministic direct polishing method (already used for past missions as Einstein, Rosat, Chandra) to ten time thinner shells. The technological challenge has been solved using a temporary stiffening structure that allows the handling and the machining of so thin glass shells. The results obtained with a prototype shell at an intermediate stage of its development (17'' HEW measured in full illumination mode with x-ray) indicate that the working concept is feasible and can be further exploited using the very large Ion Beam Facility available in our labs for the final high accuracy figuring of the thin shells. In this paper we present the required tolerances for the shell realization, the shells production chain flow and the ion beam facility up grading. Forecast on figuring time and expected performances of the figuring will also be given on the basis on the metrological data collected during past shell development.

  19. An Effective Multi-Frame Super Resolution of Image from Blurry and Noisy Images Using PCA

    Directory of Open Access Journals (Sweden)

    Swati A. Patil

    2014-01-01

    Full Text Available Image super-resolution are techniques aiming restoration of a high-resolution image from one or several low-resolution observation images, which offer the advantages overcoming some of the inherent resolution limitations of low-cost imaging sensors (e.g., satellite image, cell phone, camera’s or surveillance camera’s, and allow better utilization of the growing capability and noise free image of HR displays. Conventional image super-resolution approaches normally require multiple LR inputs of the same scene with sub-pixel motions. This paper attempts to undertake the study of the super-resolution restoration problem and improved resolution image is restored from several geometrically warped, blurred, noisy images. The super-resolution restoration problem is modeled and analyzed from the filters such as Median Filter, Adaptive Wiener Filter, Gaussian Filter these different noise densities have been removed between 10% to 65%. The Principal Component analysis (PCA is the technique which is useful for improving the image sharpness after the process of de-blurring

  20. High resolution field imaging with atomic vapor cells

    OpenAIRE

    Horsley, Andrew

    2015-01-01

    In this thesis, I report on the development of imaging techniques in atomic vapor cells. This is a relatively unexplored area, despite the ubiquitous use of imaging in experiments with ultracold atoms. Our main focus is in high resolution imaging of microwave near fields, for which there is currently no satisfactory established technique. We detect microwave fields through Rabi oscillations driven by the microwave on atomic hyperfine transitions. The technique can be easily modified to also i...

  1. Molecular outflows and hot molecular cores in G24.78+0.08 at sub-arcsecond angular resolution

    Science.gov (United States)

    Beltrán, M. T.; Cesaroni, R.; Zhang, Q.; Galván-Madrid, R.; Beuther, H.; Fallscheer, C.; Neri, R.; Codella, C.

    2011-08-01

    Context. This study is part of a large project to study the physics of accretion and molecular outflows towards a selected sample of high-mass star-forming regions that show evidence of infall and rotation from previous studies. Aims: We wish to make a thorough study at high-angular resolution of the structure and kinematics of the HMCs and corresponding molecular outflows in the high-mass star-forming region G24.78+0.08. Methods: We carried out SMA and IRAM PdBI observations at 1.3 and 1.4 mm, respectively, of dust and of typical high-density and molecular outflow tracers with resolutions of < 1″. Complementary IRAM 30-m 12CO and 13CO observations were carried out to recover the short spacing information of the molecular outflows. Results: The millimeter continuum emission towards cores G24 A1 and A2 has been resolved into three and two cores, respectively, and named A1, A1b, A1c, A2, and A2b. All these cores are aligned in a southeast-northwest direction coincident with that of the molecular outflows detected in the region, which suggests a preferential direction for star formation in this region. The masses of the cores range from 7 to 22 M⊙, and the rotational temperatures from 128 to 180 K. The high-density tracers have revealed the existence of two velocity components towards A1. One of them peaks close to the position of the millimeter continuum peak and of the HC Hii region and is associated with the velocity gradient seen in CH3CN towards this core, while the other one peaks southwest of core A1 and is not associated with any millimeter continuum emission peak. The position-velocity plots along outflow A and the 13CO (2-1) averaged blueshifted and redshifted emission indicate that this outflow is driven by core A2. Core A1 apparently does not drive any outflow. The knotty appearance of the highly collimated outflow C and the 12CO position-velocity plot suggest an episodic outflow, where the knots are made of swept-up ambient gas.

  2. Texture analysis of high-resolution FLAIR images for TLE

    Science.gov (United States)

    Jafari-Khouzani, Kourosh; Soltanian-Zadeh, Hamid; Elisevich, Kost

    2005-04-01

    This paper presents a study of the texture information of high-resolution FLAIR images of the brain with the aim of determining the abnormality and consequently the candidacy of the hippocampus for temporal lobe epilepsy (TLE) surgery. Intensity and volume features of the hippocampus from FLAIR images of the brain have been previously shown to be useful in detecting the abnormal hippocampus in TLE. However, the small size of the hippocampus may limit the texture information. High-resolution FLAIR images show more details of the abnormal intensity variations of the hippocampi and therefore are more suitable for texture analysis. We study and compare the low and high-resolution FLAIR images of six epileptic patients. The hippocampi are segmented manually by an expert from T1-weighted MR images. Then the segmented regions are mapped on the corresponding FLAIR images for texture analysis. The 2-D wavelet transforms of the hippocampi are employed for feature extraction. We compare the ability of the texture features from regular and high-resolution FLAIR images to distinguish normal and abnormal hippocampi. Intracranial EEG results as well as surgery outcome are used as gold standard. The results show that the intensity variations of the hippocampus are related to the abnormalities in the TLE.

  3. Reference-free method for forming a three-dimensional image and determining the angular velocity of a remote object

    Science.gov (United States)

    Mandrosov, V. I.

    2012-07-01

    We propose a reference-free method for forming a threedimensional image and for determining the angular velocity of a remote nonplanar object. The method is based on probing an object by laser radiation with a coherence length that is smaller or larger than the size of the object and on the use of a screen with radial holes in the centres of which photodetectors are located, the screen being mounted in the region of the flat image of the object. A threedimensional image of the object is constructed using the visibility of the interference fringes formed behind the screen due to radiation beams scattered by the object which pass through various pairs of holes (one of the holes is fixed). The three components of the angular velocity vector of the object are determined by the power spectrum of the electric signal produced during the movement of interference fringes on a photodetector mounted behind the screen.

  4. A True Multi-modality Approach for High Resolution Optical Imaging: Photo-Magnetic Imaging

    OpenAIRE

    Luk, Alex T.; Ha, Seunghoon; Nouizi, Farouk; Thayer, David; Lin, Yuting; Gulsen, Gultekin

    2014-01-01

    Multi-modality imaging leverages the competitive advantage of different imaging systems to improve the overall resolution and quantitative accuracy. Our new technique, Photo-Magnetic Imaging (PMI) is one of these true multi-modality imaging approaches, which can provide quantitative optical absorption map at MRI spatial resolution. PMI uses laser light to illuminate tissue and elevate its temperature while utilizing MR thermometry to measure the laser-induced temperature variation with high s...

  5. Resolution-recovery-embedded image reconstruction for a high-resolution animal SPECT system.

    Science.gov (United States)

    Zeraatkar, Navid; Sajedi, Salar; Farahani, Mohammad Hossein; Arabi, Hossein; Sarkar, Saeed; Ghafarian, Pardis; Rahmim, Arman; Ay, Mohammad Reza

    2014-11-01

    The small-animal High-Resolution SPECT (HiReSPECT) is a dedicated dual-head gamma camera recently designed and developed in our laboratory for imaging of murine models. Each detector is composed of an array of 1.2 × 1.2 mm(2) (pitch) pixelated CsI(Na) crystals. Two position-sensitive photomultiplier tubes (H8500) are coupled to each head's crystal. In this paper, we report on a resolution-recovery-embedded image reconstruction code applicable to the system and present the experimental results achieved using different phantoms and mouse scans. Collimator-detector response functions (CDRFs) were measured via a pixel-driven method using capillary sources at finite distances from the head within the field of view (FOV). CDRFs were then fitted by independent Gaussian functions. Thereafter, linear interpolations were applied to the standard deviation (σ) values of the fitted Gaussians, yielding a continuous map of CDRF at varying distances from the head. A rotation-based maximum-likelihood expectation maximization (MLEM) method was used for reconstruction. A fast rotation algorithm was developed to rotate the image matrix according to the desired angle by means of pre-generated rotation maps. The experiments demonstrated improved resolution utilizing our resolution-recovery-embedded image reconstruction. While the full-width at half-maximum (FWHM) radial and tangential resolution measurements of the system were over 2 mm in nearly all positions within the FOV without resolution recovery, reaching around 2.5 mm in some locations, they fell below 1.8 mm everywhere within the FOV using the resolution-recovery algorithm. The noise performance of the system was also acceptable; the standard deviation of the average counts per voxel in the reconstructed images was 6.6% and 8.3% without and with resolution recovery, respectively.

  6. High resolution surface plasmon microscopy for cell imaging

    Science.gov (United States)

    Argoul, F.; Monier, K.; Roland, T.; Elezgaray, J.; Berguiga, L.

    2010-04-01

    We introduce a new non-labeling high resolution microscopy method for cellular imaging. This method called SSPM (Scanning Surface Plasmon Microscopy) pushes down the resolution limit of surface plasmon resonance imaging (SPRi) to sub-micronic scales. High resolution SPRi is obtained by the surface plasmon lauching with a high numerical aperture objective lens. The advantages of SPPM compared to other high resolution SPRi's rely on three aspects; (i) the interferometric detection of the back reflected light after plasmon excitation, (ii) the twodimensional scanning of the sample for image reconstruction, (iii) the radial polarization of light, enhancing both resolution and sensitivity. This microscope can afford a lateral resolution of - 150 nm in liquid environment and - 200 nm in air. We present in this paper images of IMR90 fibroblasts obtained with SSPM in dried environment. Internal compartments such as nucleus, nucleolus, mitochondria, cellular and nuclear membrane can be recognized without labelling. We propose an interpretation of the ability of SSPM to reveal high index contrast zones by a local decomposition of the V (Z) function describing the response of the SSPM.

  7. GNSS Carrier Phase Integer Ambiguity Resolution with Camera and Satellite images

    Science.gov (United States)

    Henkel, Patrick

    2015-04-01

    Ambiguity Resolution is the key to high precision position and attitude determination with GNSS. However, ambiguity resolution of kinematic receivers becomes challenging in environments with substantial multipath, limited satellite availability and erroneous cycle slip corrections. There is a need for other sensors, e.g. inertial sensors that allow an independent prediction of the position. The change of the predicted position over time can then be used for cycle slip detection and correction. In this paper, we provide a method to improve the initial ambiguity resolution for RTK and PPP with vision-based position information. Camera images are correlated with geo-referenced aerial/ satellite images to obtain an independent absolute position information. This absolute position information is then coupled with the GNSS and INS measurements in an extended Kalman filter to estimate the position, velocity, acceleration, attitude, angular rates, code multipath and biases of the accelerometers and gyroscopes. The camera and satellite images are matched based on some characteristic image points (e.g. corners of street markers). We extract these characteristic image points from the camera images by performing the following steps: An inverse mapping (homogenous projection) is applied to transform the camera images from the driver's perspective to bird view. Subsequently, we detect the street markers by performing (a) a color transformation and reduction with adaptive brightness correction to focus on relevant features, (b) a subsequent morphological operation to enhance the structure recognition, (c) an edge and corner detection to extract feature points, and (d) a point matching of the corner points with a template to recognize the street markers. We verified the proposed method with two low-cost u-blox LEA 6T GPS receivers, the MPU9150 from Invensense, the ASCOS RTK corrections and a PointGrey camera. The results show very precise and seamless position and attitude

  8. Subsurface Super-resolution Imaging of Unstained Polymer Nanostructures

    Science.gov (United States)

    Urban, Ben E.; Dong, Biqin; Nguyen, The-Quyen; Backman, Vadim; Sun, Cheng; Zhang, Hao F.

    2016-01-01

    Optical imaging has offered unique advantages in material researches, such as spectroscopy and lifetime measurements of deeply embedded materials, which cannot be matched using electron or scanning-probe microscopy. Unfortunately, conventional optical imaging cannot provide the spatial resolutions necessary for many nanoscopic studies. Despite recent rapid progress, super-resolution optical imaging has yet to be widely applied to non-biological materials. Herein we describe a method for nanoscopic optical imaging of buried polymer nanostructures without the need for extrinsic staining. We observed intrinsic stochastic fluorescence emission or blinking from unstained polymers and performed spatial-temporal spectral analysis to investigate its origin. We further applied photon localization super-resolution imaging reconstruction to the detected stochastic blinking, and achieved a spatial resolution of at least 100 nm, which corresponds to a six-fold increase over the optical diffraction limit. This work demonstrates the potential for studying the static heterogeneities of intrinsic polymer molecular-specific properties at sub-diffraction-limited optical resolutions. PMID:27354178

  9. Precision cosmology with time delay lenses: high resolution imaging requirements

    CERN Document Server

    Meng, Xiao-Lei; Agnello, Adriano; Auger, Matthew W; Liao, Kai; Marshall, Philip J

    2015-01-01

    Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host galaxies of lensed quasars, which appear as "Einstein Rings" in high resolution images. We carry out a systematic exploration of the high resolution imaging required to exploit the thousands of lensed quasars that will be discovered by current and upcoming surveys with the next decade. Specifically, we simulate realistic lens systems as imaged by the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and ground based adaptive optics images taken with Keck or the Thirty Meter Telescope (TMT). We compare the performance of these pointed observations with that of images taken by the Euclid (VIS), Wide-Field Infrared Survey Telescope (WFIRST) and Large Synoptic Survey Telescope (LSST) surveys. We use as our metric the precision with which the slope $\\gamma'$ of the...

  10. Super Resolution from Hyperview Image Stack by Spatial Multiplexing

    Science.gov (United States)

    Grasnick, Armin

    2016-09-01

    An image stack for a hyperview representation could contain millions of different perspective views with extreme image similarity. The recording of all views from a computational 3d model implicates a lateral displacement of the virtual camera. Because of the huge number of views, the offset in between two adjoining camera positions can be very minor. If such a virtual setup reproduces a real hyperview screen setup, the offset can be below the wavelength of the visible light. But even with such small changes, there is an intrinsic probability for a measurable difference in between two neighbour images. Such image dissimilarity can be proofed successfully also in very basic 3d scenes. By using a quantity of juxtapositional images from the hyperview image stack, the resolution of the rendered images can be considerably improved, which is commonly known as super resolution. The utilisation of super resolution images in hyperview could cut the necessity of full frame computing and will reduce the effective render time.

  11. High-resolution Imaging Techniques for the Assessment of Osteoporosis

    Science.gov (United States)

    Krug, Roland; Burghardt, Andrew J.; Majumdar, Sharmila; Link, Thomas M.

    2010-01-01

    Synopsis The importance of assessing the bone’s microarchitectural make-up in addition to its mineral density in the context of osteoporosis has been emphasized in a number of publications. The high spatial resolution required to resolve the bone’s microstructure in a clinically feasible scan time is challenging. Currently, the best suited modalities meeting these requirements in vivo are high-resolution peripheral quantitative imaging (HR-pQCT) and magnetic resonance imaging (MRI). Whereas HR-pQCT is limited to peripheral skeleton regions like the wrist and ankle, MRI can also image other sites like the proximal femur but usually with lower spatial resolution. In addition Multidetector-CT has been used for high-resolution imaging of trabecular bone structure, however, the radiation dose is a limiting factor. This article provides an overview of the different modalities, technical requirements and recent developments in this emerging field. Details regarding imaging protocols as well as image post-processing methods for bone structure quantification are discussed. PMID:20609895

  12. Angular Variation of Solar Feature Contrast in Full-Disk G-Band Images

    Science.gov (United States)

    Blunt, Sarah Caroline; Criscuoli, Serena; Ermolli, Ilaria; Giorgi, Fabrizio

    2015-01-01

    We investigate the center-to-limb variation (CLV) of the contrasts of four types of solar surface features observed in the G-Band (430.6 nm, FWHM 1.2 nm) by analyzing 12 high quality full-disk images obtained from the Rome Precision Solar Photometric Telescope. The studied features, specifically network, enhanced network, plage, and bright plage, were singled out based on their brightness signatures in mean simultaneous Ca II K images using an intensity threshold technique. We compared our results with those obtained from high-resolution (HR) observations, and with the outputs of the spectral synthesis performed on semi-empirical models and magneto hydrodynamic (MHD) simulations. We find that the measured contrasts are systematically lower than those of HR observational results, as was expected due to the lower resolution of the analyzed observations. We also find that our observations best reflect the CLV derived from the recent one-dimensional atmospheric models described in Fontenla et al 2011 with respect to results obtained from earlier similar models. The measured CLV also agrees with those derived from the syntheses of MHD simulations and HR observations, if spatial resolution effects are properly taken into account. This work was carried out through the National Solar Observatory Summer Research Assistantship (SRA) Program. The National Solar Observatory is operated by the Association of Universities for Research in Astronomy, Inc. (AURA) under cooperative agreement with the National Science Foundation. This work was also partially supported by the European Union's Seventh Programme for Research, Technological Development and Demonstration under the grant agreements in 312495 (SOLARNET) and 313188 (SOLID).

  13. High-resolution SPECT for small-animal imaging

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This article presents a brief overview of the development of high-resolution SPECT for small-animal imaging. A pinhole collimator has been used for high-resolution animal SPECT to provide better spatial resolution and detection efficiency in comparison with a parallel-hole collimator. The theory of imaging characteristics of the pinhole collimator is presented and the designs of the pinhole aperture are discussed. The detector technologies used for the development of small-animal SPECT and the recent advances are presented. The evolving trend of small-animal SPECT is toward a multi-pinhole and a multi-detector system to obtain a high resolution and also a high detection efficiency.

  14. Image Resolution in the Digital Era: Notion and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Vahid Rakhshan

    2014-05-01

    Full Text Available Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs.

  15. Image Resolution in the Digital Era: Notion and Clinical Implications

    Directory of Open Access Journals (Sweden)

    Vahid Rakhshan

    2014-12-01

    Full Text Available Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs.

  16. Image Resolution in the Digital Era: Notion and Clinical Implications

    Science.gov (United States)

    Rakhshan, Vahid

    2014-01-01

    Digital radiographs need additional metadata in order to be accurate when being converted to analog media. Resolution is a major reason of failures in proper printing or digitizing the images. This letter shortly explains the overlooked pitfalls of digital radiography and photography in dental practice, and briefly instructs the reader how to avoid or rectify common problems associated with resolution calibration of digital radiographs. PMID:25469352

  17. Super-resolution imaging based on virtual Airy spot

    Science.gov (United States)

    Liu, Zhengjun; Guo, Cheng; Cui, Junning; Wu, Qun

    2015-02-01

    Based on the theoretical model of Airy spot, a method is proposed for improving the imaging speed from confocal microscopy. The virtual Airy spot is designed for obtaining the pattern on CCD at detecting plane. Here the size of the spot is determined by the parameters of imaging system and intensity data from point detector, which can receive data quicker than CCD. The treatment can improve the speed of imaging comparing with CCD at receiving end. The virtual structured detection is also utilized for generating high-resolution image. Some numerical simulation results are provided for demonstrating the validity of the proposed method.

  18. High Resolution Linear Polarimetric Imaging for the Event Horizon Telescope

    CERN Document Server

    Chael, Andrew A; Narayan, Ramesh; Doeleman, Sheperd S; Wardle, John F C; Bouman, Katherine L

    2016-01-01

    Images of the linear polarization of synchrotron radiation around Active Galactic Nuclei (AGN) identify their projected magnetic field lines and provide key data for understanding the physics of accretion and outflow from supermassive black holes. The highest resolution polarimetric images of AGN are produced with Very Long Baseline Interferometry (VLBI). Because VLBI incompletely samples the Fourier transform of the source image, any image reconstruction that fills in unmeasured spatial frequencies will not be unique and reconstruction algorithms are required. In this paper, we explore extensions of the Maximum Entropy Method (MEM) to linear polarimetric VLBI imaging. In contrast to previous work, our polarimetric MEM algorithm combines a Stokes I imager that uses only bispectrum measurements that are immune to atmospheric phase corruption with a joint Stokes Q and U imager that operates on robust polarimetric ratios. We demonstrate the effectiveness of our technique on 7- and 3-mm wavelength quasar observat...

  19. High Speed and High Resolution Table-Top Nanoscale Imaging

    CERN Document Server

    Tadesse, G K; Demmler, S; HÄdrich, S; Wahyutama, I; Steinert, M; Spielmann, C; ZÜrch, M; TÜnnermann, A; Limpert, J; Rothhardt, J

    2016-01-01

    We present a table-top coherent diffraction imaging (CDI) experiment based on high-order harmonics generated at 18 nm by a high average power femtosecond fiber laser system. The high photon flux, narrow spectral bandwidth and high degree of spatial coherence allow for ultra-high sub-wavelength resolution imaging at a high numerical aperture. Our experiments demonstrate a half-pitch resolution of 13.6 nm, very close to the actual Abbe-limit of 12.4 nm, which is the highest resolution achieved from any table-top XUV or X-ray microscope. In addition, 20.5 nm resolution was achieved with only 3 sec of integration time bringing live diffraction imaging and 3D tomography on the nanoscale one step closer to reality. The current resolution is solely limited by the wavelength and the detector size. Thus, table-top nanoscopes with only a few-nm resolutions are in reach and will find applications in many areas of science and technology.

  20. Demosaiced pixel super-resolution for multiplexed holographic color imaging.

    Science.gov (United States)

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-01-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired. PMID:27353242

  1. Demosaiced pixel super-resolution for multiplexed holographic color imaging

    Science.gov (United States)

    Wu, Yichen; Zhang, Yibo; Luo, Wei; Ozcan, Aydogan

    2016-06-01

    To synthesize a holographic color image, one can sequentially take three holograms at different wavelengths, e.g., at red (R), green (G) and blue (B) parts of the spectrum, and digitally merge them. To speed up the imaging process by a factor of three, a Bayer color sensor-chip can also be used to demultiplex three wavelengths that simultaneously illuminate the sample and digitally retrieve individual set of holograms using the known transmission spectra of the Bayer color filters. However, because the pixels of different channels (R, G, B) on a Bayer color sensor are not at the same physical location, conventional demosaicing techniques generate color artifacts in holographic imaging using simultaneous multi-wavelength illumination. Here we demonstrate that pixel super-resolution can be merged into the color de-multiplexing process to significantly suppress the artifacts in wavelength-multiplexed holographic color imaging. This new approach, termed Demosaiced Pixel Super-Resolution (D-PSR), generates color images that are similar in performance to sequential illumination at three wavelengths, and therefore improves the speed of holographic color imaging by 3-fold. D-PSR method is broadly applicable to holographic microscopy applications, where high-resolution imaging and multi-wavelength illumination are desired.

  2. Towards an automatic tool for resolution evaluation of mammographic images

    Energy Technology Data Exchange (ETDEWEB)

    De Oliveira, J. E. E. [FUMEC, Av. Alfonso Pena 3880, CEP 30130-009 Belo Horizonte - MG (Brazil); Nogueira, M. S., E-mail: juliae@fumec.br [Centro de Desenvolvimento da Tecnologia Nuclear / CNEN, Pte. Antonio Carlos 6627, 31270-901, Belo Horizonte - MG (Brazil)

    2014-08-15

    Quality of Mammographies from the Public and Private Services of the State. With an essentially educational character, an evaluation of the image quality is monthly held from a breast phantom in each mammographic equipment. In face of this, this work proposes to develop a protocol for automatic evaluation of image quality of mammograms so that the radiological protection and image quality requirements are met in the early detection of breast cancer. Specifically, image resolution will be addressed and evaluated, as a part of the program of image quality evaluation. Results show that for the fourth resolution and using 28 phantom images with the ground truth settled, the computer analysis of the resolution is promising and may be used as a tool for the assessment of the image quality. (Author)

  3. Towards an automatic tool for resolution evaluation of mammographic images

    International Nuclear Information System (INIS)

    Quality of Mammographies from the Public and Private Services of the State. With an essentially educational character, an evaluation of the image quality is monthly held from a breast phantom in each mammographic equipment. In face of this, this work proposes to develop a protocol for automatic evaluation of image quality of mammograms so that the radiological protection and image quality requirements are met in the early detection of breast cancer. Specifically, image resolution will be addressed and evaluated, as a part of the program of image quality evaluation. Results show that for the fourth resolution and using 28 phantom images with the ground truth settled, the computer analysis of the resolution is promising and may be used as a tool for the assessment of the image quality. (Author)

  4. High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: Multiwavelength analysis

    Science.gov (United States)

    Adam, R.; Comis, B.; Bartalucci, I.; Adane, A.; Ade, P.; André, P.; Arnaud, M.; Beelen, A.; Belier, B.; Benoît, A.; Bideaud, A.; Billot, N.; Bourrion, O.; Calvo, M.; Catalano, A.; Coiffard, G.; D'Addabbo, A.; Désert, F.-X.; Doyle, S.; Goupy, J.; Hasnoun, B.; Hermelo, I.; Kramer, C.; Lagache, G.; Leclercq, S.; Macías-Pérez, J.-F.; Martino, J.; Mauskopf, P.; Mayet, F.; Monfardini, A.; Pajot, F.; Pascale, E.; Perotto, L.; Pointecouteau, E.; Ponthieu, N.; Pratt, G. W.; Revéret, V.; Ritacco, A.; Rodriguez, L.; Savini, G.; Schuster, K.; Sievers, A.; Triqueneaux, S.; Tucker, C.; Zylka, R.

    2016-02-01

    The prototype of the NIKA2 camera, NIKA, is a dual-band instrument operating at the IRAM 30-m telescope, which can observe the sky simultaneously at 150 and 260 GHz. One of the main goals of NIKA (and NIKA2) is to measure the pressure distribution in galaxy clusters at high angular resolution using the thermal Sunyaev-Zel'dovich (tSZ) effect. Such observations have already proved to be an excellent probe of cluster pressure distributions even at intermediate and high redshifts. However, an important fraction of clusters host sub-millimeter and/or radio point sources, which can significantly affect the reconstructed signal. Here we report on sub-millimeter point sources. We examine the morphological distribution of the tSZ signal and compare it to other datasets. The NIKA data are combined with Herschel satellite data to study the spectral energy distribution (SED) of the sub-millimeter point source contaminants. We then perform a joint reconstruction of the intracluster medium (ICM) electronic pressure and density by combining NIKA, Planck, XMM-Newton, and Chandra data, focusing on the impact of the radio and sub-millimeter sources on the reconstructed pressureprofile. We find that large-scale pressure distribution is unaffected by the point sources because of the resolved nature of the NIKA observations. The reconstructed pressure in the inner region is slightly higher when the contribution of point sources are removed. We show that it is not possible to set strong constraints on the central pressure distribution without accurately removing these contaminants. The comparison with X-ray only data shows good agreement for the pressure, temperature, and entropy profiles, which all indicate that MACS J1423.8+2404 is a dynamically relaxed cool core system. The present observations illustrate the possibility of measuring these quantities with a relatively small integration time, even at high redshift and without X-ray spectroscopy. This work is part of a pilot study

  5. High resolution imaging with impulse based thermoacoustic tomography

    Science.gov (United States)

    Kellnberger, Stephan; Hajiaboli, Amir; Sergiadis, George; Razansky, Daniel; Ntziachristos, Vasilis

    2011-07-01

    Existing imaging modalities like microwave- or radiofrequency (RF) induced thermoacoustic tomography systems show the potential for resolving structures deep inside tissue due to the high penetration properties of RF. However, one of the major drawbacks of existing thermoacoustic tomography systems with pulse modulated carrier frequency excitation is the compromise between efficient signal generation and attainable spatial resolution. In order to overcome limitations of conventional thermoacoustic imaging methods, we herein present and experimentally validate our novel approach towards high resolution thermoacoustic tomography. Instead of carrier-frequency amplification, we utilize ultrahigh-energy electromagnetic impulses at nanosecond duration with near-field energy coupling, thus maintaining thermoacoustic signal strength without compromising spatial resolution. Preliminary experiments on highly absorbing objects, consisting of copper wires with characteristic sizes of ~100 μm, reveal the resolution performance which yields 160 μm. Furthermore, benefits like its cost effectiveness, simplicity and compactness with the potential application in small animal imaging as well as human body imaging show that thermoacoustic tomography with impulse excitation is a promising imaging modality which has a broad range of applications.

  6. HIGH RESOLUTION REAL-TIME MEDICAL IMAGING BASED ON PARALLEL BEAMFORMING TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Wang Lutao; Jin Gang; Xu Hongbing

    2011-01-01

    Improvement of frame-rate is very important for high quality ultrasound imaging of fast-moving structures.It is also one of the key technologies of Three-Dimension (3-D) real-time medical imaging.In this paper,we have demonstrated a beamforming method which gives imaging frame-rate increment without sacrificing the quality of medical images.By using wider and fewer transmit beams in combination with four narrower parallel receive beams,potentially increasing the imaging frame-rate by a factor four.Through employing full transmit aperture,controlling the mainlobe width,and suppressing sidelobes of angular responses,the inherent gain loss of normal parallel beamfomer can be compensated in the maximal degree.The noise and interference signals also can be suppressed effectively.Finally,we show comparable lateral resolution and contrast of ultrasound images to normal single widow weighting beamformer on simulated phantoms of point targets,cyst and fetus of 12th week.As the computational cost is linear with the number of array elements and the same with Delay And Sum (DAS) beamformers,this method has great advantages of possibility for high frame-rate real-time applications.

  7. Fractal image compression: A resolution independent representation for imagery

    Science.gov (United States)

    Sloan, Alan D.

    1993-01-01

    A deterministic fractal is an image which has low information content and no inherent scale. Because of their low information content, deterministic fractals can be described with small data sets. They can be displayed at high resolution since they are not bound by an inherent scale. A remarkable consequence follows. Fractal images can be encoded at very high compression ratios. This fern, for example is encoded in less than 50 bytes and yet can be displayed at resolutions with increasing levels of detail appearing. The Fractal Transform was discovered in 1988 by Michael F. Barnsley. It is the basis for a new image compression scheme which was initially developed by myself and Michael Barnsley at Iterated Systems. The Fractal Transform effectively solves the problem of finding a fractal which approximates a digital 'real world image'.

  8. High resolution ultrasound and photoacoustic imaging of single cells.

    Science.gov (United States)

    Strohm, Eric M; Moore, Michael J; Kolios, Michael C

    2016-03-01

    High resolution ultrasound and photoacoustic images of stained neutrophils, lymphocytes and monocytes from a blood smear were acquired using a combined acoustic/photoacoustic microscope. Photoacoustic images were created using a pulsed 532 nm laser that was coupled to a single mode fiber to produce output wavelengths from 532 nm to 620 nm via stimulated Raman scattering. The excitation wavelength was selected using optical filters and focused onto the sample using a 20× objective. A 1000 MHz transducer was co-aligned with the laser spot and used for ultrasound and photoacoustic images, enabling micrometer resolution with both modalities. The different cell types could be easily identified due to variations in contrast within the acoustic and photoacoustic images. This technique provides a new way of probing leukocyte structure with potential applications towards detecting cellular abnormalities and diseased cells at the single cell level.

  9. High resolution ultrasound and photoacoustic imaging of single cells

    Directory of Open Access Journals (Sweden)

    Eric M. Strohm

    2016-03-01

    Full Text Available High resolution ultrasound and photoacoustic images of stained neutrophils, lymphocytes and monocytes from a blood smear were acquired using a combined acoustic/photoacoustic microscope. Photoacoustic images were created using a pulsed 532 nm laser that was coupled to a single mode fiber to produce output wavelengths from 532 nm to 620 nm via stimulated Raman scattering. The excitation wavelength was selected using optical filters and focused onto the sample using a 20× objective. A 1000 MHz transducer was co-aligned with the laser spot and used for ultrasound and photoacoustic images, enabling micrometer resolution with both modalities. The different cell types could be easily identified due to variations in contrast within the acoustic and photoacoustic images. This technique provides a new way of probing leukocyte structure with potential applications towards detecting cellular abnormalities and diseased cells at the single cell level.

  10. High Spectral Resolution, High Cadence, Imaging X-Ray Microcalorimeters for Solar Physics

    Science.gov (United States)

    Bandler, Simon R.; Bailey, Catherine N.; Bookbinder, Jay A.; DeLuca, Edward E.; Chervenak, Jay A.; Eckart, Megan E.; Finkbeiner, Fred M.; Kelley, Daniel P.; Kelley, Richard L.; Kilbourne, Caroline A.; Porter, Frederick S.; Sadleir, Jack E.; Smith, Stephen J.; Smith, Randall K.

    2010-01-01

    High spectral resolution, high cadence, imaging x-ray spectroscopy has the potential to revolutionize the study of the solar corona. To that end we have been developing transition-edge-sensor (TES) based x-ray micro calorimeter arrays for future solar physics missions where imaging and high energy resolution spectroscopy will enable previously impossible studies of the dynamics and energetics of the solar corona. The characteristics of these x-ray microcalorimeters are significantly different from conventional micro calorimeters developed for astrophysics because they need to accommodate much higher count rates (300-1000 cps) while maintaining high energy resolution of less than 4 eV FWHM in the X-ray energy band of 0.2-10 keV. The other main difference is a smaller pixel size (less than 75 x 75 square microns) than is typical for x-ray micro calorimeters in order to provide angular resolution less than 1 arcsecond. We have achieved at energy resolution of 2.15 eV at 6 keV in a pixel with a 12 x 12 square micron TES sensor and 34 x 34 x 9.1 micron gold absorber, and a resolution of 2.30 eV at 6 keV in a pixel with a 35 x 35 micron TES and a 57 x 57 x 9.1 micron gold absorber. This performance has been achieved in pixels that are fabricated directly onto solid substrates, ie. they are not supported by silicon nitride membranes. We present the results from these detectors, the expected performance at high count-rates, and prospects for the use of this technology for future Solar missions.

  11. Locomotion of microspheres for super-resolution imaging

    OpenAIRE

    Krivitsky, Leonid A.; Jia Jun Wang; Zengbo Wang; Boris Luk'yanchuk

    2013-01-01

    Super-resolution imaging using sub-diffraction field localization by micron sized transparent beads (microspheres) was recently demonstrated [1]. Practical applications in microscopy require control over the positioning of the microspheres. We present a simple method of positioning and controllable movement of a microsphere by using a glass micropipette. This allows sub-diffraction imaging at arbitrary points in three dimensions, as well as the ability to track moving objects. The results are...

  12. Direct Imaging of Transient Fano Resonances in N2 Using Time-, Energy-, and Angular-Resolved Photoelectron Spectroscopy

    Science.gov (United States)

    Eckstein, Martin; Yang, Chung-Hsin; Frassetto, Fabio; Poletto, Luca; Sansone, Giuseppe; Vrakking, Marc J. J.; Kornilov, Oleg

    2016-04-01

    Autoionizing Rydberg states of molecular N2 are studied using time-, energy-, and angular-resolved photoelectron spectroscopy. A femtosecond extreme ultraviolet pulse with a photon energy of 17.5 eV excites the resonance and a subsequent IR pulse ionizes the molecule before the autoionization takes place. The angular-resolved photoelectron spectra depend on pump-probe time delay and allow for the distinguishing of two electronic states contributing to the resonance. The lifetime of one of the contributions is determined to be 14 ±1 fs , while the lifetime of the other appears to be significantly shorter than the time resolution of the experiment. These observations suggest that the Rydberg states in this energy region are influenced by the effect of interference stabilization and merge into a complex resonance.

  13. Direct Imaging of Transient Fano Resonances in N_{2} Using Time-, Energy-, and Angular-Resolved Photoelectron Spectroscopy.

    Science.gov (United States)

    Eckstein, Martin; Yang, Chung-Hsin; Frassetto, Fabio; Poletto, Luca; Sansone, Giuseppe; Vrakking, Marc J J; Kornilov, Oleg

    2016-04-22

    Autoionizing Rydberg states of molecular N_{2} are studied using time-, energy-, and angular-resolved photoelectron spectroscopy. A femtosecond extreme ultraviolet pulse with a photon energy of 17.5 eV excites the resonance and a subsequent IR pulse ionizes the molecule before the autoionization takes place. The angular-resolved photoelectron spectra depend on pump-probe time delay and allow for the distinguishing of two electronic states contributing to the resonance. The lifetime of one of the contributions is determined to be 14±1  fs, while the lifetime of the other appears to be significantly shorter than the time resolution of the experiment. These observations suggest that the Rydberg states in this energy region are influenced by the effect of interference stabilization and merge into a complex resonance. PMID:27152799

  14. High spatial resolution X-UV Fresnel zone plates imaging

    International Nuclear Information System (INIS)

    The goal of this work is to study the capabilities of imaging of Fresnel zone plates in the 1.5. and 2 keV X-ray range for the imaging of laser-produced plasmas. The diagnostic is composed of a Fresnel zone plate with good imaging capabilities and a multilayer mirror to select the spectral emission bandwidth of the plasma we want to study. This diagnostic was evaluated at the Centre d'Etudes de Limeil-Valenton experiments to study spatial resolution with this kind of X-ray source. The images we obtained showed that there is no geometric aberrations over an object field of several millimetre. Fresnen zone plates are often used for monochromatic biological objects imaging in the water window around 400 eV but they offer large prospects for laser produced plasma imaging. (author)

  15. High resolution image reconstruction with constrained, total-variation minimization

    CERN Document Server

    Sidky, Emil Y; Duchin, Yuval; Ullberg, Christer; Pan, Xiaochuan

    2011-01-01

    This work is concerned with applying iterative image reconstruction, based on constrained total-variation minimization, to low-intensity X-ray CT systems that have a high sampling rate. Such systems pose a challenge for iterative image reconstruction, because a very fine image grid is needed to realize the resolution inherent in such scanners. These image arrays lead to under-determined imaging models whose inversion is unstable and can result in undesirable artifacts and noise patterns. There are many possibilities to stabilize the imaging model, and this work proposes a method which may have an advantage in terms of algorithm efficiency. The proposed method introduces additional constraints in the optimization problem; these constraints set to zero high spatial frequency components which are beyond the sensing capability of the detector. The method is demonstrated with an actual CT data set and compared with another method based on projection up-sampling.

  16. Using Progressive Resolution to Visualize large Satellite Image dataset

    Science.gov (United States)

    ho, yuan; ramanmurthy, mohan

    2014-05-01

    Unidata's Integrated Data Viewer (IDV) is a Java-based software application that provides new and innovative ways of displaying satellite imagery, gridded data, and surface, upper air, and radar data within a unified interface. Progressive Resolution (PR) is a advanced feature newly developed in the IDV. When loading a large satellite dataset with PR turned on, the IDV calculates the resolution of the view window, sets the magnification factors dynamically, and loads a sufficient amount of the data to generate an image at the correct resolution. A rubber band box (RBB) interface allows the user to zoom in/out or change the projection, forcing the IDV to recalculate the magnification factors and get higher/lower resolution data. This new feature improves the IDV memory usage significantly. In the preliminary test, loading 100 time steps of GOES-East 1 km 0.65 visible image data (100 X 10904 X 6928) with PR, both memory and CPU usage are comparable to generating a single time-step display at full resolution (10904 X 6928), and the quality of the resulting image is not compromised. The PR feature is currently available for both satellite imagery and gridded datasets, and will be expanded to other datasets. In this presentation we will present examples of PR usage with large satellite datasets for academic investigations and scientific discovery.

  17. Coregistration of high-resolution Mars orbital images

    Science.gov (United States)

    Sidiropoulos, Panagiotis; Muller, Jan-Peter

    2015-04-01

    The systematic orbital imaging of the Martian surface started 4 decades ago from NASA's Viking Orbiter 1 & 2 missions, which were launched in August 1975, and acquired orbital images of the planet between 1976 and 1980. The result of this reconnaissance was the first medium-resolution (i.e. ≤ 300m/pixel) global map of Mars, as well as a variety of high-resolution images (reaching up to 8m/pixel) of special regions of interest. Over the last two decades NASA has sent 3 more spacecraft with onboard instruments for high-resolution orbital imaging: Mars Global Surveyor (MGS) having onboard the Mars Orbital Camera - Narrow Angle (MOC-NA), Mars Odyssey having onboard the Thermal Emission Imaging System - Visual (THEMIS-VIS) and the Mars Reconnaissance Orbiter (MRO) having on board two distinct high-resolution cameras, Context Camera (CTX) and High-Resolution Imaging Science Experiment (HiRISE). Moreover, ESA has the multispectral High resolution Stereo Camera (HRSC) onboard ESA's Mars Express with resolution up to 12.5m since 2004. Overall, this set of cameras have acquired more than 400,000 high-resolution images, i.e. with resolution better than 100m and as fine as 25 cm/pixel. Notwithstanding the high spatial resolution of the available NASA orbital products, their accuracy of areo-referencing is often very poor. As a matter of fact, due to pointing inconsistencies, usually form errors in roll attitude, the acquired products may actually image areas tens of kilometers far away from the point that they are supposed to be looking at. On the other hand, since 2004, the ESA Mars Express has been acquiring stereo images through the High Resolution Stereo Camera (HRSC), with resolution that is usually 12.5-25 metres per pixel. The achieved coverage is more than 64% for images with resolution finer than 20 m/pixel, while for ~40% of Mars, Digital Terrain Models (DTMs) have been produced with are co-registered with MOLA [Gwinner et al., 2010]. The HRSC images and DTMs

  18. Towards Adaptive High-Resolution Images Retrieval Schemes

    Science.gov (United States)

    Kourgli, A.; Sebai, H.; Bouteldja, S.; Oukil, Y.

    2016-06-01

    Nowadays, content-based image-retrieval techniques constitute powerful tools for archiving and mining of large remote sensing image databases. High spatial resolution images are complex and differ widely in their content, even in the same category. All images are more or less textured and structured. During the last decade, different approaches for the retrieval of this type of images have been proposed. They differ mainly in the type of features extracted. As these features are supposed to efficiently represent the query image, they should be adapted to all kind of images contained in the database. However, if the image to recognize is somewhat or very structured, a shape feature will be somewhat or very effective. While if the image is composed of a single texture, a parameter reflecting the texture of the image will reveal more efficient. This yields to use adaptive schemes. For this purpose, we propose to investigate this idea to adapt the retrieval scheme to image nature. This is achieved by making some preliminary analysis so that indexing stage becomes supervised. First results obtained show that by this way, simple methods can give equal performances to those obtained using complex methods such as the ones based on the creation of bag of visual word using SIFT (Scale Invariant Feature Transform) descriptors and those based on multi scale features extraction using wavelets and steerable pyramids.

  19. 3D spatial resolution and spectral resolution of interferometric 3D imaging spectrometry.

    Science.gov (United States)

    Obara, Masaki; Yoshimori, Kyu

    2016-04-01

    Recently developed interferometric 3D imaging spectrometry (J. Opt. Soc. Am A18, 765 [2001]1084-7529JOAOD610.1364/JOSAA.18.000765) enables obtainment of the spectral information and 3D spatial information for incoherently illuminated or self-luminous object simultaneously. Using this method, we can obtain multispectral components of complex holograms, which correspond directly to the phase distribution of the wavefronts propagated from the polychromatic object. This paper focuses on the analysis of spectral resolution and 3D spatial resolution in interferometric 3D imaging spectrometry. Our analysis is based on a novel analytical impulse response function defined over four-dimensional space. We found that the experimental results agree well with the theoretical prediction. This work also suggests a new criterion and estimate method regarding 3D spatial resolution of digital holography. PMID:27139648

  20. Super-resolution Microscopy in Plant Cell Imaging.

    Science.gov (United States)

    Komis, George; Šamajová, Olga; Ovečka, Miroslav; Šamaj, Jozef

    2015-12-01

    Although the development of super-resolution microscopy methods dates back to 1994, relevant applications in plant cell imaging only started to emerge in 2010. Since then, the principal super-resolution methods, including structured-illumination microscopy (SIM), photoactivation localization microscopy (PALM), stochastic optical reconstruction microscopy (STORM), and stimulated emission depletion microscopy (STED), have been implemented in plant cell research. However, progress has been limited due to the challenging properties of plant material. Here we summarize the basic principles of existing super-resolution methods and provide examples of applications in plant science. The limitations imposed by the nature of plant material are reviewed and the potential for future applications in plant cell imaging is highlighted.

  1. Multispectral high-resolution hologram generation using orthographic projection images

    Science.gov (United States)

    Muniraj, I.; Guo, C.; Sheridan, J. T.

    2016-08-01

    We present a new method of synthesizing a digital hologram of three-dimensional (3D) real-world objects from multiple orthographic projection images (OPI). A high-resolution multiple perspectives of 3D objects (i.e., two dimensional elemental image array) are captured under incoherent white light using synthetic aperture integral imaging (SAII) technique and their OPIs are obtained respectively. The reference beam is then multiplied with the corresponding OPI and integrated to form a Fourier hologram. Eventually, a modified phase retrieval algorithm (GS/HIO) is applied to reconstruct the hologram. The principle is validated experimentally and the results support the feasibility of the proposed method.

  2. Locomotion of microspheres for super-resolution imaging

    Science.gov (United States)

    Krivitsky, Leonid A.; Wang, Jia Jun; Wang, Zengbo; Luk'yanchuk, Boris

    2013-12-01

    Super-resolution virtual imaging by micron sized transparent beads (microspheres) was recently demonstrated by Wang et al. Practical applications in microscopy require control over the positioning of the microspheres. Here we present a method of positioning and controllable movement of a microsphere by using a fine glass micropipette. This allows sub-diffraction imaging at arbitrary points in three dimensions, as well as the ability to track moving objects. The results are relevant to a broad scope of applications, including sample inspection, microfabrication, and bio-imaging.

  3. High-resolution Image Reconstruction by Neural Network and Its Application in Infrared Imaging

    Institute of Scientific and Technical Information of China (English)

    ZHANG Nan; JIN Wei-qi; SU Bing-hua

    2005-01-01

    As digital image techniques have been widely used, the requirements for high-resolution images become increasingly stringent. Traditional single-frame interpolation techniques cannot add new high frequency information to the expanded images, and cannot improve resolution in deed. Multiframe-based techniques are effective ways for high-resolution image reconstruction, but their computation complexities and the difficulties in achieving image sequences limit their applications. An original method using an artificial neural network is proposed in this paper. Using the inherent merits in neural network, we can establish the mapping between high frequency components in low-resolution images and high-resolution images. Example applications and their results demonstrated the images reconstructed by our method are aesthetically and quantitatively (using the criteria of MSE and MAE) superior to the images acquired by common methods. Even for infrared images this method can give satisfactory results with high definition. In addition, a single-layer linear neural network is used in this paper, the computational complexity is very low, and this method can be realized in real time.

  4. A 2D eye gaze estimation system with low-resolution webcam images

    Directory of Open Access Journals (Sweden)

    Kim Jin

    2011-01-01

    Full Text Available Abstract In this article, a low-cost system for 2D eye gaze estimation with low-resolution webcam images is presented. Two algorithms are proposed for this purpose, one for the eye-ball detection with stable approximate pupil-center and the other one for the eye movements' direction detection. Eyeball is detected using deformable angular integral search by minimum intensity (DAISMI algorithm. Deformable template-based 2D gaze estimation (DTBGE algorithm is employed as a noise filter for deciding the stable movement decisions. While DTBGE employs binary images, DAISMI employs gray-scale images. Right and left eye estimates are evaluated separately. DAISMI finds the stable approximate pupil-center location by calculating the mass-center of eyeball border vertices to be employed for initial deformable template alignment. DTBGE starts running with initial alignment and updates the template alignment with resulting eye movements and eyeball size frame by frame. The horizontal and vertical deviation of eye movements through eyeball size is considered as if it is directly proportional with the deviation of cursor movements in a certain screen size and resolution. The core advantage of the system is that it does not employ the real pupil-center as a reference point for gaze estimation which is more reliable against corneal reflection. Visual angle accuracy is used for the evaluation and benchmarking of the system. Effectiveness of the proposed system is presented and experimental results are shown.

  5. Simulated Photoelectron-Based Imaging of Localized Surface Plasmons with Attosecond Resolution

    Science.gov (United States)

    Prell, James; Borja, Lauren; Gandman, Andrey; Whitmore, Desire; Neumark, Daniel; Leone, Stephen

    2013-03-01

    Simulations of proposed photoelectron streaking experiments in the presence of an oscillating plasmon field are presented. The results indicate that localized surface plasmon dephasing can be imaged with attosecond resolution using electron time-of-flight (TOF) or velocity map imaging (VMI) techniques. In the simulation, localized surface plasmons are excited in metal nanoparticles by a few-cycle infrared or visible laser pulse. Using time-delayed single, isolated attosecond x-ray pulses, electrons are photoemitted from the metallic nanoparticles and streaked by both the plasmon and laser electric fields. The effects of these two fields in the streaking spectra and images can be separated so that the temporal evolution of the plasmon electric field can be directly extracted. The plasmon electric field induces a broadening of the photoelectron speed distribution with an envelope directly proportional to that of the plasmon dipole moment. Plasmon-induced oscillation of the angular distribution in VMI is predicted to report the spatial distribution of the plasmon electric field for nanoparticles with high aspect ratios. The simulations indicate that these techniques can be used to map plasmon dynamics with unprecedented temporal resolution.

  6. Special issue on high-resolution optical imaging

    Science.gov (United States)

    Smith, Peter J. S.; Davis, Ilan; Galbraith, Catherine G.; Stemmer, Andreas

    2013-09-01

    The pace of development in the field of advanced microscopy is truly breath-taking, and is leading to major breakthroughs in our understanding of molecular machines and cell function. This special issue of Journal of Optics draws attention to a number of interesting approaches, ranging from fluorescence and imaging of unlabelled cells, to computational methods, all of which are describing the ever increasing detail of the dynamic behaviour of molecules in the living cell. This is a field which traditionally, and currently, demonstrates a marvellous interplay between the disciplines of physics, chemistry and biology, where apparent boundaries to resolution dissolve and living cells are viewed in ever more clarity. It is fertile ground for those interested in optics and non-conventional imaging to contribute high-impact outputs in the fields of cell biology and biomedicine. The series of articles presented here has been selected to demonstrate this interdisciplinarity and to encourage all those with a background in the physical sciences to 'dip their toes' into the exciting and dynamic discoveries surrounding cell function. Although single molecule super-resolution microscopy is commercially available, specimen preparation and interpretation of single molecule data remain a major challenge for scientists wanting to adopt the techniques. The paper by Allen and Davidson [1] provides a much needed detailed introduction to the practical aspects of stochastic optical reconstruction microscopy, including sample preparation, image acquisition and image analysis, as well as a brief description of the different variants of single molecule localization microscopy. Since super-resolution microscopy is no longer restricted to three-dimensional imaging of fixed samples, the review by Fiolka [2] is a timely introduction to techniques that have been successfully applied to four-dimensional live cell super-resolution microscopy. The combination of multiple high-resolution techniques

  7. Learning-based compressed sensing for infrared image super resolution

    Science.gov (United States)

    Zhao, Yao; Sui, Xiubao; Chen, Qian; Wu, Shaochi

    2016-05-01

    This paper presents an infrared image super-resolution method based on compressed sensing (CS). First, the reconstruction model under the CS framework is established and a Toeplitz matrix is selected as the sensing matrix. Compared with traditional learning-based methods, the proposed method uses a set of sub-dictionaries instead of two coupled dictionaries to recover high resolution (HR) images. And Toeplitz sensing matrix allows the proposed method time-efficient. Second, all training samples are divided into several feature spaces by using the proposed adaptive k-means classification method, which is more accurate than the standard k-means method. On the basis of this approach, a complex nonlinear mapping from the HR space to low resolution (LR) space can be converted into several compact linear mappings. Finally, the relationships between HR and LR image patches can be obtained by multi-sub-dictionaries and HR infrared images are reconstructed by the input LR images and multi-sub-dictionaries. The experimental results show that the proposed method is quantitatively and qualitatively more effective than other state-of-the-art methods.

  8. Adaptive optics with pupil tracking for high resolution retinal imaging.

    Science.gov (United States)

    Sahin, Betul; Lamory, Barbara; Levecq, Xavier; Harms, Fabrice; Dainty, Chris

    2012-02-01

    Adaptive optics, when integrated into retinal imaging systems, compensates for rapidly changing ocular aberrations in real time and results in improved high resolution images that reveal the photoreceptor mosaic. Imaging the retina at high resolution has numerous potential medical applications, and yet for the development of commercial products that can be used in the clinic, the complexity and high cost of the present research systems have to be addressed. We present a new method to control the deformable mirror in real time based on pupil tracking measurements which uses the default camera for the alignment of the eye in the retinal imaging system and requires no extra cost or hardware. We also present the first experiments done with a compact adaptive optics flood illumination fundus camera where it was possible to compensate for the higher order aberrations of a moving model eye and in vivo in real time based on pupil tracking measurements, without the real time contribution of a wavefront sensor. As an outcome of this research, we showed that pupil tracking can be effectively used as a low cost and practical adaptive optics tool for high resolution retinal imaging because eye movements constitute an important part of the ocular wavefront dynamics.

  9. Ultrasound-aided high-resolution biophotonic imaging

    Science.gov (United States)

    Wang, Lihong V.

    2003-10-01

    We develop novel biophotonic imaging for early-cancer detection, a grand challenge in cancer research, using nonionizing electromagnetic and ultrasonic waves. Unlike ionizing x-ray radiation, nonionizing electromagnetic waves such as optical waves are safe for biomedical applications and reveal new contrast mechanisms and functional information. For example, our spectroscopic oblique-incidence reflectometry can detect skin cancers based on functional hemoglobin parameters and cell nuclear size with 95% accuracy. Unfortunately, electromagnetic waves in the nonionizing spectral region do not penetrate biological tissue in straight paths as do x-rays. Consequently, high-resolution tomography based on nonionizing electromagnetic waves alone, as demonstrated by our Mueller optical coherence tomography, is limited to superficial tissue imaging. Ultrasonic imaging, on the contrary, furnishes good imaging resolution but has poor contrast in early-stage tumors and has strong speckle artifacts as well. We developed ultrasound-mediated imaging modalities by combining electromagnetic and ultrasonic waves synergistically. The hybrid modalities yield speckle-free electromagnetic-contrast at ultrasonic resolution in relatively large biological tissue. In ultrasound-modulated (acousto)-optical tomography, a focused ultrasonic wave encodes diffuse laser light in scattering biological tissue. In photo-acoustic (thermo-acoustic) tomography, a low-energy laser (RF) pulse induces ultrasonic waves in biological tissue due to thermoelastic expansion.

  10. Natural-pose hand detection in low-resolution images

    Directory of Open Access Journals (Sweden)

    Nyan Bo Bo1

    2009-07-01

    Full Text Available Robust real-time hand detection and tracking in video sequences would enable many applications in areas as diverse ashuman-computer interaction, robotics, security and surveillance, and sign language-based systems. In this paper, we introducea new approach for detecting human hands that works on single, cluttered, low-resolution images. Our prototype system, whichis primarily intended for security applications in which the images are noisy and low-resolution, is able to detect hands as smallas 2424 pixels in cluttered scenes. The system uses grayscale appearance information to classify image sub-windows as eithercontaining or not containing a human hand very rapidly at the cost of a high false positive rate. To improve on the false positiverate of the main classifier without affecting its detection rate, we introduce a post-processor system that utilizes the geometricproperties of skin color blobs. When we test our detector on a test image set containing 106 hands, 92 of those hands aredetected (86.8% detection rate, with an average false positive rate of 1.19 false positive detections per image. The rapiddetection speed, the high detection rate of 86.8%, and the low false positive rate together ensure that our system is useable asthe main detector in a diverse variety of applications requiring robust hand detection and tracking in low-resolution, clutteredscenes.

  11. Enhancement of the low resolution image quality using randomly sampled data for multi-slice MR imaging

    OpenAIRE

    Pang, Yong; Yu, Baiying; Zhang, Xiaoliang

    2014-01-01

    Low resolution images are often acquired in in vivo MR applications involving in large field-of-view (FOV) and high speed imaging, such as, whole-body MRI screening and functional MRI applications. In this work, we investigate a multi-slice imaging strategy for acquiring low resolution images by using compressed sensing (CS) MRI to enhance the image quality without increasing the acquisition time. In this strategy, low resolution images of all the slices are acquired using multiple-slice imag...

  12. Providing Internet Access to High-Resolution Lunar Images

    Science.gov (United States)

    Plesea, Lucian

    2008-01-01

    The OnMoon server is a computer program that provides Internet access to high-resolution Lunar images, maps, and elevation data, all suitable for use in geographical information system (GIS) software for generating images, maps, and computational models of the Moon. The OnMoon server implements the Open Geospatial Consortium (OGC) Web Map Service (WMS) server protocol and supports Moon-specific extensions. Unlike other Internet map servers that provide Lunar data using an Earth coordinate system, the OnMoon server supports encoding of data in Moon-specific coordinate systems. The OnMoon server offers access to most of the available high-resolution Lunar image and elevation data. This server can generate image and map files in the tagged image file format (TIFF) or the Joint Photographic Experts Group (JPEG), 8- or 16-bit Portable Network Graphics (PNG), or Keyhole Markup Language (KML) format. Image control is provided by use of the OGC Style Layer Descriptor (SLD) protocol. Full-precision spectral arithmetic processing is also available, by use of a custom SLD extension. This server can dynamically add shaded relief based on the Lunar elevation to any image layer. This server also implements tiled WMS protocol and super-overlay KML for high-performance client application programs.

  13. Providing Internet Access to High-Resolution Mars Images

    Science.gov (United States)

    Plesea, Lucian

    2008-01-01

    The OnMars server is a computer program that provides Internet access to high-resolution Mars images, maps, and elevation data, all suitable for use in geographical information system (GIS) software for generating images, maps, and computational models of Mars. The OnMars server is an implementation of the Open Geospatial Consortium (OGC) Web Map Service (WMS) server. Unlike other Mars Internet map servers that provide Martian data using an Earth coordinate system, the OnMars WMS server supports encoding of data in Mars-specific coordinate systems. The OnMars server offers access to most of the available high-resolution Martian image and elevation data, including an 8-meter-per-pixel uncontrolled mosaic of most of the Mars Global Surveyor (MGS) Mars Observer Camera Narrow Angle (MOCNA) image collection, which is not available elsewhere. This server can generate image and map files in the tagged image file format (TIFF), Joint Photographic Experts Group (JPEG), 8- or 16-bit Portable Network Graphics (PNG), or Keyhole Markup Language (KML) format. Image control is provided by use of the OGC Style Layer Descriptor (SLD) protocol. The OnMars server also implements tiled WMS protocol and super-overlay KML for high-performance client application programs.

  14. High-resolution three-dimensional imaging radar

    Science.gov (United States)

    Cooper, Ken B. (Inventor); Chattopadhyay, Goutam (Inventor); Siegel, Peter H. (Inventor); Dengler, Robert J. (Inventor); Schlecht, Erich T. (Inventor); Mehdi, Imran (Inventor); Skalare, Anders J. (Inventor)

    2010-01-01

    A three-dimensional imaging radar operating at high frequency e.g., 670 GHz, is disclosed. The active target illumination inherent in radar solves the problem of low signal power and narrow-band detection by using submillimeter heterodyne mixer receivers. A submillimeter imaging radar may use low phase-noise synthesizers and a fast chirper to generate a frequency-modulated continuous-wave (FMCW) waveform. Three-dimensional images are generated through range information derived for each pixel scanned over a target. A peak finding algorithm may be used in processing for each pixel to differentiate material layers of the target. Improved focusing is achieved through a compensation signal sampled from a point source calibration target and applied to received signals from active targets prior to FFT-based range compression to extract and display high-resolution target images. Such an imaging radar has particular application in detecting concealed weapons or contraband.

  15. Developing terahertz imaging equation and enhancement of the resolution of terahertz images using deconvolution

    Science.gov (United States)

    Ahi, Kiarash; Anwar, Mehdi

    2016-04-01

    This paper introduces a novel reconstruction approach for enhancing the resolution of the terahertz (THz) images. For this purpose the THz imaging equation is derived. According to our best knowledge we are reporting the first THz imaging equation by this paper. This imaging equation is universal for THz far-field imaging systems and can be used for analyzing, describing and modeling of these systems. The geometry and behavior of Gaussian beams in far-field region imply that the FWHM of the THz beams diverge as the frequencies of the beams decrease. Thus, the resolution of the measurement decreases in lower frequencies. On the other hand, the depth of penetration of THz beams decreases as frequency increases. Roughly speaking beams in sub 1.5 THz, are transmitted into integrated circuit (IC) packages and the similar packaged objects. Thus, it is not possible to use the THz pulse with higher frequencies in order to achieve higher resolution inspection of packaged items. In this paper, after developing the 3-D THz point spread function (PSF) of the scanning THz beam and then the THz imaging equation, THz images are enhanced through deconvolution of the THz PSF and THz images. As a result, the resolution has been improved several times beyond the physical limitations of the THz measurement setup in the far-field region and sub-Nyquist images have been achieved. Particularly, MSE and SSIḾ have been increased by 27% and 50% respectively. Details as small as 0.2 mm were made visible in the THz images which originally reveals no details smaller than 2.2 mm. In other words the resolution of the images has been increased by 10 times. The accuracy of the reconstructed images was proved by high resolution X-ray images.

  16. Improved delineation of short cortical association fibers and gray/white matter boundary using whole-brain three-dimensional diffusion tensor imaging at submillimeter spatial resolution.

    Science.gov (United States)

    Song, Allen W; Chang, Hing-Chiu; Petty, Christopher; Guidon, Arnaud; Chen, Nan-Kuei

    2014-11-01

    Recent emergence of human connectome imaging has led to a high demand on angular and spatial resolutions for diffusion magnetic resonance imaging (MRI). While there have been significant growths in high angular resolution diffusion imaging, the improvement in spatial resolution is still limited due to a number of technical challenges, such as the low signal-to-noise ratio and high motion artifacts. As a result, the benefit of a high spatial resolution in the whole-brain connectome imaging has not been fully evaluated in vivo. In this brief report, the impact of spatial resolution was assessed in a newly acquired whole-brain three-dimensional diffusion tensor imaging data set with an isotropic spatial resolution of 0.85 mm. It was found that the delineation of short cortical association fibers is drastically improved as well as the definition of fiber pathway endings into the gray/white matter boundary-both of which will help construct a more accurate structural map of the human brain connectome.

  17. A Novel and Efficient Lifting Scheme based Super Resolution Reconstruction for Early Detection of Cancer in Low Resolution Mammogram Images

    Directory of Open Access Journals (Sweden)

    Liyakathunisa

    2011-05-01

    Full Text Available Mammography is the most effective method for early detection of breast diseases. However, thetypical diagnostic signs, such as masses and microcalcifications, are difficult to be detectedbecause mammograms are low contrast and noisy images. We concentrate on a special case ofsuper resolution reconstruction for early detection of cancer from low resolution mammogramimages. Super resolution reconstruction is the process of combining several low resolutionimages into a single higher resolution image. This paper describes a novel approach forenhancing the resolution of mammographic images. We are proposing an efficient lifting waveletbased denoising with adaptive interpolation for super resolution reconstruction. Under this framework, the digitized low resolution mammographic images are decomposed into many levels toobtain different frequency bands. We use Daubechies (D4 lifting schemes to decompose lowresolution mammogram images into multilevel scale and wavelet coefficients. Then our proposednovel soft thresholding technique is used to remove the noisy coefficients, by fixing optimumthreshold value. In order to obtain an image of higher resolution adaptive interpolation is applied.Our proposed lifting wavelet transform based restoration and adaptive interpolation preserves theedges as well as smoothens the image without introducing artifacts. The proposed algorithmavoids the application of iterative method, reduces the complexity of calculation and applies tolarge dimension low-resolution images. Experimental results show that the proposed approachhas succeeded in obtaining a high-resolution mammogram image with a high PSNR, ISNR ratioand a good visual quality.

  18. Noise and physical limits to maximum resolution of PET images

    Energy Technology Data Exchange (ETDEWEB)

    Herraiz, J.L.; Espana, S. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain); Vicente, E.; Vaquero, J.J.; Desco, M. [Unidad de Medicina y Cirugia Experimental, Hospital GU ' Gregorio Maranon' , E-28007 Madrid (Spain); Udias, J.M. [Dpto. Fisica Atomica, Molecular y Nuclear, Facultad de Ciencias Fisicas, Universidad Complutense de Madrid, Avda. Complutense s/n, E-28040 Madrid (Spain)], E-mail: jose@nuc2.fis.ucm.es

    2007-10-01

    In this work we show that there is a limit for the maximum resolution achievable with a high resolution PET scanner, as well as for the best signal-to-noise ratio, which are ultimately related to the physical effects involved in the emission and detection of the radiation and thus they cannot be overcome with any particular reconstruction method. These effects prevent the spatial high frequency components of the imaged structures to be recorded by the scanner. Therefore, the information encoded in these high frequencies cannot be recovered by any reconstruction technique. Within this framework, we have determined the maximum resolution achievable for a given acquisition as a function of data statistics and scanner parameters, like the size of the crystals or the inter-crystal scatter. In particular, the noise level in the data as a limitation factor to yield high-resolution images in tomographs with small crystal sizes is outlined. These results have implications regarding how to decide the optimal number of voxels of the reconstructed image or how to design better PET scanners.

  19. Photoacoustic lymphatic imaging with high spatial-temporal resolution

    Science.gov (United States)

    Martel, Catherine; Yao, Junjie; Huang, Chih-Hsien; Zou, Jun; Randolph, Gwendalyn J.; Wang, Lihong V.

    2014-11-01

    Despite its critical function in coordinating the egress of inflammatory and immune cells out of tissues and maintaining fluid balance, the causative role of lymphatic network dysfunction in pathological settings is still understudied. Engineered-animal models and better noninvasive high spatial-temporal resolution imaging techniques in both preclinical and clinical studies will help to improve our understanding of different lymphatic-related pathologic disorders. Our aim was to take advantage of our newly optimized noninvasive wide-field fast-scanning photoacoustic (PA) microcopy system to coordinately image the lymphatic vasculature and its flow dynamics, while maintaining high resolution and detection sensitivity. Here, by combining the optical-resolution PA microscopy with a fast-scanning water-immersible microelectromechanical system scanning mirror, we have imaged the lymph dynamics over a large field-of-view, with high spatial resolution and advanced detection sensitivity. Depending on the application, lymphatic vessels (LV) were spectrally or temporally differentiated from blood vessels. Validation experiments were performed on phantoms and in vivo to identify the LV. Lymphatic flow dynamics in nonpathological and pathological conditions were also visualized. These results indicate that our newly developed PA microscopy is a promising tool for lymphatic-related biological research.

  20. High resolution hyperspectral imaging with a high throughput virtual slit

    Science.gov (United States)

    Gooding, Edward A.; Gunn, Thomas; Cenko, Andrew T.; Hajian, Arsen R.

    2016-05-01

    Hyperspectral imaging (HSI) device users often require both high spectral resolution, on the order of 1 nm, and high light-gathering power. A wide entrance slit assures reasonable étendue but degrades spectral resolution. Spectrometers built using High Throughput Virtual Slit™ (HTVS) technology optimize both parameters simultaneously. Two remote sensing use cases that require high spectral resolution are discussed. First, detection of atmospheric gases with intrinsically narrow absorption lines, such as hydrocarbon vapors or combustion exhaust gases such as NOx and CO2. Detecting exhaust gas species with high precision has become increasingly important in the light of recent events in the automobile industry. Second, distinguishing reflected daylight from emission spectra in the visible and NIR (VNIR) regions is most easily accomplished using the Fraunhofer absorption lines in solar spectra. While ground reflectance spectral features in the VNIR are generally quite broad, the Fraunhofer lines are narrow and provide a signature of intrinsic vs. extrinsic illumination. The High Throughput Virtual Slit enables higher spectral resolution than is achievable with conventional spectrometers by manipulating the beam profile in pupil space. By reshaping the instrument pupil with reflective optics, HTVS-equipped instruments create a tall, narrow image profile at the exit focal plane, typically delivering 5X or better the spectral resolution achievable with a conventional design.

  1. Spatial scales of pollution from variable resolution satellite imaging

    International Nuclear Information System (INIS)

    The Moderate Resolution Imaging Spectroradiometer (MODIS) provides daily global coverage, but the 10 km resolution of its aerosol optical depth (AOD) product is not adequate for studying spatial variability of aerosols in urban areas. Recently, a new Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for MODIS which provides AOD at 1 km resolution. Using MAIAC data, the relationship between MAIAC AOD and PM2.5 as measured by the EPA ground monitoring stations was investigated at varying spatial scales. Our analysis suggested that the correlation between PM2.5 and AOD decreased significantly as AOD resolution was degraded. This is so despite the intrinsic mismatch between PM2.5 ground level measurements and AOD vertically integrated measurements. Furthermore, the fine resolution results indicated spatial variability in particle concentration at a sub-10 km scale. Finally, this spatial variability of AOD within the urban domain was shown to depend on PM2.5 levels and wind speed. - Highlights: ► The correlation between PM2.5 and AOD decreases as AOD resolution is degraded. ► High resolution MAIAC AOD 1 km retrieval can be used to investigate within-city PM2.5 variability. ► Low pollution days exhibit higher spatial variability of AOD and PM2.5 then moderate pollution days. ► AOD spatial variability within urban area is higher during the lower wind speed conditions. - The correlation between PM2.5 and AOD decreases as AOD resolution is degraded. The new high-resolution MAIAC AOD retrieval has the potential to capture PM2.5 variability at the intra-urban scale.

  2. Image Super-Resolution via Adaptive Regularization and Sparse Representation.

    Science.gov (United States)

    Cao, Feilong; Cai, Miaomiao; Tan, Yuanpeng; Zhao, Jianwei

    2016-07-01

    Previous studies have shown that image patches can be well represented as a sparse linear combination of elements from an appropriately selected over-complete dictionary. Recently, single-image super-resolution (SISR) via sparse representation using blurred and downsampled low-resolution images has attracted increasing interest, where the aim is to obtain the coefficients for sparse representation by solving an l0 or l1 norm optimization problem. The l0 optimization is a nonconvex and NP-hard problem, while the l1 optimization usually requires many more measurements and presents new challenges even when the image is the usual size, so we propose a new approach for SISR recovery based on regularization nonconvex optimization. The proposed approach is potentially a powerful method for recovering SISR via sparse representations, and it can yield a sparser solution than the l1 regularization method. We also consider the best choice for lp regularization with all p in (0, 1), where we propose a scheme that adaptively selects the norm value for each image patch. In addition, we provide a method for estimating the best value of the regularization parameter λ adaptively, and we discuss an alternate iteration method for selecting p and λ . We perform experiments, which demonstrates that the proposed regularization nonconvex optimization method can outperform the convex optimization method and generate higher quality images.

  3. Detection of engineering vehicles in high-resolution monitoring images

    Institute of Scientific and Technical Information of China (English)

    Xun LIU; Yin ZHANG; San-yuan ZHANG; Ying WANG; Zhong-yan LIANG; Xiu-zi YE

    2015-01-01

    This paper presents a novel formulation for detecting objects with articulated rigid bodies from high-resolution monitoring images, particularly engineering vehicles. There are many pixels in high-resolution monitoring images, and most of them represent the background. Our method fi rst detects object patches from monitoring images using a coarse detection process. In this phase, we build a descriptor based on histograms of oriented gradient, which contain color frequency information. Then we use a linear support vector machine to rapidly detect many image patches that may contain object parts, with a low false negative rate and a high false positive rate. In the second phase, we apply a refi nement classifi cation to determine the patches that actually contain objects. In this stage, we increase the size of the image patches so that they include the complete object using models of the object parts. Then an accelerated and improved salient mask is used to improve the performance of the dense scale-invariant feature transform descriptor. The detection process returns the absolute position of positive objects in the original images. We have applied our methods to three datasets to demonstrate their effectiveness.

  4. Super-Resolution Image Reconstruction Applied to Medical Ultrasound

    Science.gov (United States)

    Ellis, Michael

    Ultrasound is the preferred imaging modality for many diagnostic applications due to its real-time image reconstruction and low cost. Nonetheless, conventional ultrasound is not used in many applications because of limited spatial resolution and soft tissue contrast. Most commercial ultrasound systems reconstruct images using a simple delay-and-sum architecture on receive, which is fast and robust but does not utilize all information available in the raw data. Recently, more sophisticated image reconstruction methods have been developed that make use of far more information in the raw data to improve resolution and contrast. One such method is the Time-Domain Optimized Near-Field Estimator (TONE), which employs a maximum a priori estimation to solve a highly underdetermined problem, given a well-defined system model. TONE has been shown to significantly improve both the contrast and resolution of ultrasound images when compared to conventional methods. However, TONE's lack of robustness to variations from the system model and extremely high computational cost hinder it from being readily adopted in clinical scanners. This dissertation aims to reduce the impact of TONE's shortcomings, transforming it from an academic construct to a clinically viable image reconstruction algorithm. By altering the system model from a collection of individual hypothetical scatterers to a collection of weighted, diffuse regions, dTONE is able to achieve much greater robustness to modeling errors. A method for efficient parallelization of dTONE is presented that reduces reconstruction time by more than an order of magnitude with little loss in image fidelity. An alternative reconstruction algorithm, called qTONE, is also developed and is able to reduce reconstruction times by another two orders of magnitude while simultaneously improving image contrast. Each of these methods for improving TONE are presented, their limitations are explored, and all are used in concert to reconstruct in

  5. [Assessment of chlorophyll content using a new vegetation index based on multi-angular hyperspectral image data].

    Science.gov (United States)

    Liao, Qin-hong; Zhang, Dong-yan; Wang, Ji-hua; Yang, Gui-jun; Yang, Hao; Coburn, Craig; Wong, Zhijie; Wang, Da-cheng

    2014-06-01

    The fast estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. This study gets the hyperspectral imagery data by using a self-developed multi-angular acquisition system during the different maize growth period, the reflectance of maize canopy was extracted accurately from the hyperspectral images under different view angles in the principal plane. The hot-dark-spot index (HDS) of red waveband was calculated through the analysis of simulated values by ACRM model and measured values, then this index was used to modify the vegetation index (TCARI), thus a new vegetation index (HD-TCARI) based on the multi-angular observation was proposed. Finally, the multi-angular hyperspectral imagery data was used to validate the vegetation indexes. The result showed that HD-TCARI could effectively reduce the LAI effects on the assessment of chlorophyll content. When the chlorophyll content was greater than 30 μg x cm(-2), the correlation (R2) between HD-TCARI and LAI was only 26.88%-28.72%. In addition, the HD-TCARI could resist the saturation of vegetation index during the assessment of high chlorophyll content. When the LAI varled from 1 to 6, the linear relation between HD-TCARI and chlorophyll content could be improved by 9% compared with TCARI. The ground validation of HD-TCARI by multi-angular hyperspectral image showed that the linear relation between HD-TCARI and chlorophyll content (R2 = 66.74%) was better than the TCARI (R2 = 39.92%), which indicated that HD-TCARI has good potentials for estimating the chlorophyll content.

  6. Broadband line imaging with subwavelength resolution using plasmonic waveguides

    OpenAIRE

    Podoliak, N.; Horak, P.; Prangsma, J.C.; Pinkse, P.W.H.

    2015-01-01

    In this paper we design a high-resolution line imaging device allowing for broadband operation at near-infrared wavelengths ranging from 1 ?m to 2 ?m utilizing the advantage of subwavelength light confinement in plasmonic waveguides. The device consists of an array of air-guided plasmonic waveguides in gold with fanned-out geometry. In the main part of the device the separation between waveguides increases gradually from the input towards the output. High resolution is achieved on the input s...

  7. Scaling-up Transformation of Multisensor Images with Multiple Resolutions.

    Science.gov (United States)

    Chen, Shaohui; Zhang, Renhua; Su, Hongbo; Tian, Jing; Xia, Jun

    2009-01-01

    For scaling up low resolution multispectral images (LRMIs) with high resolution panchromatic image (HRPI), intensity-hue-saturation (IHS) can produce satisfactory spatial enhancement but usually introduces spectral distortion in the fused high resolution multispectral images (HRMIs). In this paper, to minimize this problem, we present a generalized intensity modulation (GIM) by extending the IHS transform to an arbitrary number of LRMIs, which uses the information of the spectral response functions (SRFs) of the multispectral and panchromatic sensors. Before modulation, the generalized intensity is enhanced by injecting details extracted from the HRPI by means of empirical mode decomposition. After the enhanced generalized intensity is substituted for the old one, the HRMIs are obtained through the GIM. Quickbird images are used to illustrate the superiority of this proposed method. Extensive comparison results based on visual analysis and Wald's protocol demonstrate that the proposed method is more encouraging for scaling up the LRMIs with the HRPI spectrally and spatially than the tested fusion methods. PMID:22573959

  8. Scaling-up Transformation of Multisensor Images with Multiple Resolutions

    Directory of Open Access Journals (Sweden)

    2009-02-01

    Full Text Available For scaling up low resolution multispectral images (LRMIs with high resolution panchromatic image (HRPI, intensity-hue-saturation (IHS can produce satisfactory spatial enhancement but usually introduces spectral distortion in the fused high resolution multispectral images (HRMIs. In this paper, to minimize this problem, we present a generalized intensity modulation (GIM by extending the IHS transform to an arbitrary number of LRMIs, which uses the information of the spectral response functions (SRFs of the multispectral and panchromatic sensors. Before modulation, the generalized intensity is enhanced by injecting details extracted from the HRPI by means of empirical mode decomposition. After the enhanced generalized intensity is substituted for the old one, the HRMIs are obtained through the GIM. Quickbird images are used to illustrate the superiority of this proposed method. Extensive comparison results based on visual analysis and Wald’s protocol demonstrate that the proposed method is more encouraging for scaling up the LRMIs with the HRPI spectrally and spatially than the tested fusion methods.

  9. Application of multi-resolution analysis in sonar image denoising

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Sonar images have complex background, low contrast, and deteriorative edges; these characteristics make it difficult for researchers to dispose the sonar objects. The multi-resolution analysis represents the signals in different scales efficiently, which is widely used in image processing. Wavelets are successful in disposing point discontinuities in one dimension, but not in two dimensions. The finite Ridgelet transform (FRIT) deals efficiently with the singularity in high dimension. It presents three improved denoising approaches, which are based on FRIT and used in the sonar image disposal technique. By experiment and comparison with traditional methods, these approaches not only suppress the artifacts, but also obtain good effect in edge keeping and SNR of the sonar image denoising.

  10. Multi-resolution image segmentation based on Gaussian mixture model

    Institute of Scientific and Technical Information of China (English)

    Tang Yinggan; Liu Dong; Guan Xinping

    2006-01-01

    Mixture model based image segmentation method, which assumes that image pixels are independent and do not consider the position relationship between pixels, is not robust to noise and usually leads to misclassification. A new segmentation method, called multi-resolution Gaussian mixture model method, is proposed. First, an image pyramid is constructed and son-father link relationship is built between each level of pyramid. Then the mixture model segmentation method is applied to the top level. The segmentation result on the top level is passed top-down to the bottom level according to the son-father link relationship between levels. The proposed method considers not only local but also global information of image, it overcomes the effect of noise and can obtain better segmentation result. Experimental result demonstrates its effectiveness.

  11. Super-Resolution Real Imaging in Microsphere-Assisted Microscopy

    Science.gov (United States)

    Wang, Feifei; Li, Yi; Jia, Boliang; Liu, Lianqing; Li, Wen Jung

    2016-01-01

    Microsphere-assisted microscopy has received a lot of attention recently due to its simplicity and its capability to surpass the diffraction limit. However, to date, sub-diffraction-limit features have only been observed in virtual images formed through the microspheres. We show that it is possible to form real, super-resolution images using high-refractive index microspheres. Also, we report on how changes to a microsphere’s refractive index and size affect image formation and planes. The relationship between the focus position and the additional magnification factor is also investigated using experimental and theoretical methods. We demonstrate that such a real imaging mode, combined with the use of larger microspheres, can enlarge sub-diffraction-limit features up to 10 times that of wide-field microscopy’s magnification with a field-of-view diameter of up to 9 μm. PMID:27768774

  12. Fast full resolution saliency detection based on incoherent imaging system

    Science.gov (United States)

    Lin, Guang; Zhao, Jufeng; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

    2016-08-01

    Image saliency detection is widely applied in many tasks in the field of the computer vision. In this paper, we combine the saliency detection with the Fourier optics to achieve acceleration of saliency detection algorithm. An actual optical saliency detection system is constructed within the framework of incoherent imaging system. Additionally, the application of our system to implement the bottom-up rapid pre-saliency process of primate visual saliency is discussed with dual-resolution camera. A set of experiments over our system are conducted and discussed. We also demonstrate the comparisons between our method and pure computer methods. The results show our system can produce full resolution saliency maps faster and more effective.

  13. Super-Resolution for Traditional and Omnidirectional Image Sequences

    Directory of Open Access Journals (Sweden)

    Attila Nagy

    2009-03-01

    Full Text Available This article presents a simple method on how to implement a super-resolutionbased video enhancement technique in .NET using the functions of the OpenCV library.First, we outline the goal of this project and after that, a short review of the steps of superresolutiontechnique is given. As a part of the discussion about the implementation itself,the general design aspects are detailed in short. Then, the different optical flow algorithmsare analyzed and the super-resolution calculation of omnidirectional image sequences isdiscussed. After all that, the achieved results can be seen and finally, a short generalconclusion can be read. This paper is a revision of our previous work [1]. In this edition,we focus on the super-resolution of omnidirectional image sequences rather than thetechnological issues that were discussed in our previous article. Further information aboutthe implementation and wrapper development can be found in [1 and 12].

  14. Fast full resolution saliency detection based on incoherent imaging system

    Science.gov (United States)

    Lin, Guang; Zhao, Jufeng; Feng, Huajun; Xu, Zhihai; Li, Qi; Chen, Yueting

    2016-05-01

    Image saliency detection is widely applied in many tasks in the field of the computer vision. In this paper, we combine the saliency detection with the Fourier optics to achieve acceleration of saliency detection algorithm. An actual optical saliency detection system is constructed within the framework of incoherent imaging system. Additionally, the application of our system to implement the bottom-up rapid pre-saliency process of primate visual saliency is discussed with dual-resolution camera. A set of experiments over our system are conducted and discussed. We also demonstrate the comparisons between our method and pure computer methods. The results show our system can produce full resolution saliency maps faster and more effective.

  15. The convergence of object dependent resolution in maximum likelihood based tomographic image reconstruction

    International Nuclear Information System (INIS)

    Study of the maximum likelihood by EM algorithm (ML) with a reconstruction kernel equal to the intrinsic detector resolution and sieve regularization has demonstrated that any image improvements over filtered backprojection (FBP) are a function of image resolution. Comparing different reconstruction algorithms potentially requires measuring and matching the image resolution. Since there are no standard methods for describing the resolution of images from a nonlinear algorithm such as ML, the authors have defined measures of effective local Gaussian resolution (ELGR) and effective global Gaussian resolution (EGGR) and examined their behaviour in FBP images and in ML images using two different measurement techniques. (Author)

  16. Low-Resolution Vehicle Image Recognition Technology by Frame-Composition of Moving Images

    Science.gov (United States)

    Kanzawa, Yusuke; Kobayashi, Hiroki; Ohkawa, Takenao; Ito, Toshio

    Developing on-board automotive driver assistance systems aiming to alert drivers about driving environments, and possible collision with other vehicles has attracted a lot of attention lately. Especially, many researchers have suggested the forward vehicle recognition technology by a camera on vehicle. In the forward vehicle recognition, however, it is difficult to detect the features of vehicle from a distant vehicle image by conventional methods because the image is too low-resolution (LR). This paper presents vehicle image recognition technology for detecting of the features of a distant vehicle by frame-composition of moving images. To detect the vehicle features of a distant LR vehicle image, we use the moving images obtained from the camera on the vehicle, and utilize super-resolution (SR) image reconstruction. SR image reconstruction is to use signal processing techniques to obtain a high-resolution (or sequence) image from observed multiple LR images. Use of this technique on real road image, we show the effectiveness of the proposed techniques.

  17. Convex Super-Resolution Detection of Lines in Images

    OpenAIRE

    Polisano, Kévin; Condat, Laurent; Clausel, Marianne; Perrier, Valérie

    2016-01-01

    International audience In this paper, we present a new convex formulation for the problem of recovering lines in degraded images. Following the recent paradigm of super-resolution, we formulate a dedicated atomic norm penalty and we solve this optimization problem by means of a primal–dual algorithm. This parsimonious model enables the reconstruction of lines from lowpass measurements, even in presence of a large amount of noise or blur. Furthermore, a Prony method performed on rows and co...

  18. Correction of Migration Through Resolution Cell in ISAR Imaging

    Institute of Scientific and Technical Information of China (English)

    JIANGZhenglin; XINGMengdao; BAOZheng

    2004-01-01

    For ISAR imaging-radar, after the translation motion compensated, the target can be changed to turntable and the R-D (Range-Doppler) algorithm usually adopted is based on small target flying steadily, with the assumption that all of the scatterers are not migrated through their range cells. But for maneuvering target this assumption is not satisfied, as the Doppler frequency is time varying. Actually, to obtain the cross-range resolution of dozens of centimeters for the large-scale or medium targets, especially for S or L wave band, with wave length so short, MTRC (the Migration through resolution cell)would occur on both fringes of the ISAR imaging. The Doppler migration is basically caused by nonuniform rotation of several parts of the target, so that the Doppler frequency of each scatterer is time varying, which can be accumulated coherently by the method of time-frequency analysis in order to get instant range-Doppler image. In this paper, the reason that causes migration through resolution cell is discussed, and a compensating algorithm is proposed. The method of time-frequency analysis to every range cell of scattererer is applied to estimate its instant frequency after range compressing and MTRC correcting,so that the quadratic term can be adjusted. Simulated data and real data prove that this method is effective.

  19. Noise and Analyzer-Crystal Angular Position Analysis for Analyzer-Based Phase-Contrast Imaging

    OpenAIRE

    Majidi, Keivan; Li, Jun; Muehleman, Carol; Brankov, Jovan G.

    2014-01-01

    The analyzer-based phase-contrast X-ray imaging (ABI) method is emerging as a potential alternative to conventional radiography. Like many of the modern imaging techniques, ABI is a computed imaging method (meaning that images are calculated from raw data). ABI can simultaneously generate a number of planar parametric images containing information about absorption, refraction, and scattering properties of an object. These images are estimated from raw data acquired by measuring (sampling) the...

  20. High resolution 3D imaging of synchrotron generated microbeams

    Energy Technology Data Exchange (ETDEWEB)

    Gagliardi, Frank M., E-mail: frank.gagliardi@wbrc.org.au [Alfred Health Radiation Oncology, The Alfred, Melbourne, Victoria 3004, Australia and School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia); Cornelius, Iwan [Imaging and Medical Beamline, Australian Synchrotron, Clayton, Victoria 3168, Australia and Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales 2500 (Australia); Blencowe, Anton [Division of Health Sciences, School of Pharmacy and Medical Sciences, The University of South Australia, Adelaide, South Australia 5000, Australia and Division of Information Technology, Engineering and the Environment, Mawson Institute, University of South Australia, Mawson Lakes, South Australia 5095 (Australia); Franich, Rick D. [School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, Victoria 3000 (Australia); Geso, Moshi [School of Medical Sciences, RMIT University, Bundoora, Victoria 3083 (Australia)

    2015-12-15

    Purpose: Microbeam radiation therapy (MRT) techniques are under investigation at synchrotrons worldwide. Favourable outcomes from animal and cell culture studies have proven the efficacy of MRT. The aim of MRT researchers currently is to progress to human clinical trials in the near future. The purpose of this study was to demonstrate the high resolution and 3D imaging of synchrotron generated microbeams in PRESAGE® dosimeters using laser fluorescence confocal microscopy. Methods: Water equivalent PRESAGE® dosimeters were fabricated and irradiated with microbeams on the Imaging and Medical Beamline at the Australian Synchrotron. Microbeam arrays comprised of microbeams 25–50 μm wide with 200 or 400 μm peak-to-peak spacing were delivered as single, cross-fire, multidirectional, and interspersed arrays. Imaging of the dosimeters was performed using a NIKON A1 laser fluorescence confocal microscope. Results: The spatial fractionation of the MRT beams was clearly visible in 2D and up to 9 mm in depth. Individual microbeams were easily resolved with the full width at half maximum of microbeams measured on images with resolutions of as low as 0.09 μm/pixel. Profiles obtained demonstrated the change of the peak-to-valley dose ratio for interspersed MRT microbeam arrays and subtle variations in the sample positioning by the sample stage goniometer were measured. Conclusions: Laser fluorescence confocal microscopy of MRT irradiated PRESAGE® dosimeters has been validated in this study as a high resolution imaging tool for the independent spatial and geometrical verification of MRT beam delivery.

  1. Direct Observation of Cosmic Strings Via Their Strong Gravitational Lensing Effect. 1. Predictions for High Resolution Imaging Surveys

    Energy Technology Data Exchange (ETDEWEB)

    Gasparini, Maria Alice; Marshall, Phil; Treu, Tommaso; /UC, Santa Barbara; Morganson, Eric; /KIPAC, Menlo Park; Dubath, Florian; /Santa Barbara, KITP

    2007-11-14

    We use current theoretical estimates for the density of long cosmic strings to predict the number of strong gravitational lensing events in astronomical imaging surveys as a function of angular resolution and survey area. We show that angular resolution is the single most important factor, and that interesting limits on the dimensionless string tension G{mu}/c{sup 2} can be obtained by existing and planned surveys. At the resolution of the Hubble Space Telescope (0'.14), it is sufficient to survey of order a square degree -- well within reach of the current HST archive -- to probe the regime G{mu}/c{sup 2} {approx} 10{sup -8}. If lensing by cosmic strings is not detected, such a survey would improve the limit on the string tension by an order of magnitude on that available from the cosmic microwave background. At the resolution (0'.028) attainable with the next generation of large ground based instruments, both in the radio and the infra-red with adaptive optics, surveying a sky area of order ten square degrees will allow us to probe the G{mu}/c{sup 2} {approx} 10{sup -9} regime. These limits will not be improved significantly by increasing the solid angle of the survey.

  2. High angular resolution Sunyaev-Zel'dovich observations of MACS J1423.8+2404 with NIKA: multi-wavelength analysis

    CERN Document Server

    Adam, R; Bartalucci, I; Adane, A; Ade, P; André, P; Arnaud, M; Beelen, A; Belier, B; Benoît, A; Bideaud, A; Billot, N; Bourrion, O; Calvo, M; Catalano, A; Coiffard, G; D'Addabbo, A; Désert, F -X; Doyle, S; Goupy, J; Hasnoun, B; Hermelo, I; Kramer, C; Lagache, G; Leclercq, S; Macías-Pérez, J -F; Martino, J; Mauskopf, P; Mayet, F; Monfardini, A; Pajot, F; Pascale, E; Perotto, L; Pointecouteau, E; Ponthieu, N; Pratt, G W; Revéret, V; Ritacco, A; Rodriguez, L; Savini, G; Schuster, K; Sievers, A; Triqueneaux, S; Tucker, C; Zylka, R

    2015-01-01

    NIKA, the prototype of the NIKA2 camera, is an instrument operating at the IRAM 30m telescope that can observe the sky simultaneously at 150 and 260GHz. One of the main goals of NIKA is to measure the pressure distribution in galaxy clusters at high angular resolution using the Sunyaev-Zel'dovich (SZ) effect. Such observations have already proved to be an excellent probe of cluster pressure distributions even at high redshifts. However, an important fraction of clusters host submm and/or radio point sources that can significantly affect the reconstructed signal. Here we report <20arcsec angular resolution observations at 150 and 260GHz of the cluster MACSJ1424, which hosts both radio and submm point sources. We examine the morphological distribution of the SZ signal and compare it to other datasets. The NIKA data are combined with Herschel satellite data to study the SED of the submm point source contaminants. We then perform a joint reconstruction of the ICM electronic pressure and density by combining NI...

  3. Imaging collagen type I fibrillogenesis with high spatiotemporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Stamov, Dimitar R, E-mail: stamov@jpk.com [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany); Stock, Erik [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany); Franz, Clemens M [DFG-Center for Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Strasse 1a, 76131 Karlsruhe (Germany); Jähnke, Torsten; Haschke, Heiko [JPK Instruments AG, Bouchéstrasse 12, 12435 Berlin (Germany)

    2015-02-15

    Fibrillar collagens, such as collagen type I, belong to the most abundant extracellular matrix proteins and they have received much attention over the last five decades due to their large interactome, complex hierarchical structure and high mechanical stability. Nevertheless, the collagen self-assembly process is still incompletely understood. Determining the real-time kinetics of collagen type I formation is therefore pivotal for better understanding of collagen type I structure and function, but visualising the dynamic self-assembly process of collagen I on the molecular scale requires imaging techniques offering high spatiotemporal resolution. Fast and high-speed scanning atomic force microscopes (AFM) provide the means to study such processes on the timescale of seconds under near-physiological conditions. In this study we have applied fast AFM tip scanning to study the assembly kinetics of fibrillar collagen type I nanomatrices with a temporal resolution reaching eight seconds for a frame size of 500 nm. By modifying the buffer composition and pH value, the kinetics of collagen fibrillogenesis can be adjusted for optimal analysis by fast AFM scanning. We furthermore show that amplitude-modulation imaging can be successfully applied to extract additional structural information from collagen samples even at high scan rates. Fast AFM scanning with controlled amplitude modulation therefore provides a versatile platform for studying dynamic collagen self-assembly processes at high resolution. - Highlights: • Continuous non-invasive time-lapse investigation of collagen I fibrillogenesis in situ. • Imaging of collagen I self-assembly with high spatiotemporal resolution. • Application of setpoint modulation to study the hierarchical structure of collagen I. • Observing real-time formation of the D-banding pattern in collagen I.

  4. Black phosphorus photodetector for multispectral, high-resolution imaging.

    Science.gov (United States)

    Engel, Michael; Steiner, Mathias; Avouris, Phaedon

    2014-11-12

    Black phosphorus is a layered semiconductor that is intensely researched in view of applications in optoelectronics. In this letter, we investigate a multilayer black phosphorus photodetector that is capable of acquiring high-contrast (V > 0.9) images both in the visible (λVIS = 532 nm) as well as in the infrared (λIR = 1550 nm) spectral regime. In a first step, by using photocurrent microscopy, we map the active area of the device and we characterize responsivity and gain. In a second step, by deploying the black phosphorus device as a point-like detector in a confocal microsope setup, we acquire diffraction-limited optical images with submicron resolution. The results demonstrate the usefulness of black phosphorus as an optoelectronic material for hyperspectral imaging applications.

  5. Detection of Barchan Dunes in High Resolution Satellite Images

    Science.gov (United States)

    Azzaoui, M. A.; Adnani, M.; El Belrhiti, H.; Chaouki, I. E.; Masmoudi, C.

    2016-06-01

    Barchan dunes are the fastest moving sand dunes in the desert. We developed a process to detect barchans dunes on High resolution satellite images. It consisted of three steps, we first enhanced the image using histogram equalization and noise reduction filters. Then, the second step proceeds to eliminate the parts of the image having a texture different from that of the barchans dunes. Using supervised learning, we tested a coarse to fine textural analysis based on Kolomogorov Smirnov test and Youden's J-statistic on co-occurrence matrix. As an output we obtained a mask that we used in the next step to reduce the search area. In the third step we used a gliding window on the mask and check SURF features with SVM to get barchans dunes candidates. Detected barchans dunes were considered as the fusion of overlapping candidates. The results of this approach were very satisfying in processing time and precision.

  6. High Resolution Image Correspondences for Video Post-Production

    Directory of Open Access Journals (Sweden)

    Marcus Magnor

    Full Text Available We present an algorithm for estimating dense image correspondences. Our versatile approach lends itself to various tasks typical for video post-processing, including image morphing, optical flow estimation, stereo rectification, disparity/depth reconstruction, and baseline adjustment. We incorporate recent advances in feature matching, energy minimization, stereo vision, and data clustering into our approach. At the core of our correspondence estimation we use Efficient Belief Propagation for energy minimization. While state-of-the-art algorithms only work on thumbnail-sized images, our novel feature downsampling scheme in combination with a simple, yet efficient data term compression, can cope with high-resolution data. The incorporation of SIFT (Scale-Invariant Feature Transform features into data term computation further resolves matching ambiguities, making long-range correspondence estimation possible. We detect occluded areas by evaluating the correspondence symmetry, we further apply Geodesic matting to automatically determine plausible values in these regions.

  7. High Resolution Image Correspondences for Video Post-Production

    Directory of Open Access Journals (Sweden)

    Marcus Magnor

    2012-12-01

    Full Text Available We present an algorithm for estimating dense image correspondences. Our versatile approach lends itself to various tasks typical for video post-processing, including image morphing, optical flow estimation, stereo rectification, disparity/depth reconstruction, and baseline adjustment. We incorporate recent advances in feature matching, energy minimization, stereo vision, and data clustering into our approach. At the core of our correspondence estimation we use Efficient Belief Propagation for energy minimization. While state-of-the-art algorithms only work on thumbnail-sized images, our novel feature downsampling scheme in combination with a simple, yet efficient data term compression, can cope with high-resolution data. The incorporation of SIFT (Scale-Invariant Feature Transform features into data term computation further resolves matching ambiguities, making long-range correspondence estimation possible. We detect occluded areas by evaluating the correspondence symmetry, we further apply Geodesic matting to automatically determine plausible values in these regions.

  8. Enhanced Landmine Detection from Low Resolution IR Image Sequences

    Science.gov (United States)

    Wang, Tiesheng; Gu, Irene Yu-Hua; Tjahjadi, Tardi

    We deal with the problem of landmine field detection using low-resolution infrared (IR) image sequences measured from airborne or vehicle-borne passive IR cameras. The proposed scheme contains two parts: a) employ a multi-scale detector, i.e., a special type of isotropic bandpass filters, to detect landmine candidates in each frame; b) enhance landmine detection through seeking maximum consensus of corresponding landmine candidates over image frames. Experiments were conducted on several IR image sequences measured from airborne and vehicle-borne cameras, where some results are included. As shown in our experiments, the landmine signatures have been significantly enhanced using the proposed scheme, and automatic detection results are reasonably good. These methods can therefore be applied to assisting humanitarian demining work for landmine field detection.

  9. High-resolution EUV imaging tools for resist exposure and aerial image monitoring

    Science.gov (United States)

    Booth, M.; Brisco, O.; Brunton, A.; Cashmore, J.; Elbourn, P.; Elliner, G.; Gower, M.; Greuters, J.; Grunewald, P.; Gutierrez, R.; Hill, T.; Hirsch, J.; Kling, L.; McEntee, N.; Mundair, S.; Richards, P.; Truffert, V.; Wallhead, I.; Whitfield, M.; Hudyma, R.

    2005-05-01

    Key features are presented of two high-resolution EUV imaging tools: the MS-13 Microstepper wafer exposure and the RIM-13 reticle imaging microscope. The MS-13 has been developed for EUV resist testing and technology evaluation at the 32nm node and beyond, while the RIM-13 is designed for actinic aerial image monitoring of blank and patterned EUV reticles. Details of the design architecture, module layout, major subsystems and performance are presented for both tools.

  10. The optical microscopy with virtual image breaks a record: 50-nm resolution imaging is demonstrated

    CERN Document Server

    Wang, Zengbo; Li, Lin; Liu, Zhu; Luk'yanchuk, Boris; Chen, Zaichun; Hong, Minghui

    2010-01-01

    We demonstrate a new 'microsphere nanoscope' that uses ordinary SiO2 microspheres as superlenses to create a virtual image of the object in near field. The magnified virtual image greatly overcomes the diffraction limit. We are able to resolve clearly 50-nm objects under a standard white light source in both transmission and reflection modes. The resolution achieved for white light opens a new opportunity to image viruses, DNA and molecules in real time.

  11. High-Resolution Images of Diffuse Neutral Clouds in the Milky Way. I. Observations, Imaging, and Basic Cloud Properties

    CERN Document Server

    Pidopryhora, Yurii; Dickey, John M; Rupen, Michael P

    2015-01-01

    A set of diffuse interstellar clouds in the inner Galaxy within a few hundred pc of the Galactic plane has been observed at an angular resolution of ~1 arcmin combining data from the NRAO Green Bank Telescope and the Very Large Array. At the distance of the clouds the linear resolution ranges from ~1.9 pc to ~2.8 pc. These clouds have been selected to be somewhat out of the Galactic plane and are thus not confused with unrelated emission, but in other respects they are a Galactic population. They are located near the tangent points in the inner Galaxy, and thus at a quantifiable distance: $2.3 \\leq R \\leq 6.0$ kpc from the Galactic Center, and $-1000 \\leq z \\leq +610$ pc from the Galactic plane. These are the first images of the diffuse neutral HI clouds that may constitute a considerable fraction of the ISM. Peak HI column densities range from $N_{HI} = 0.8-2.9 \\times 10^{20}$ cm$^{-2}$. Cloud diameters vary between about 10 and 100 pc, and their HI mass spans the range from less than a hundred to a few thou...

  12. High-performance VGA-resolution digital color CMOS imager

    Science.gov (United States)

    Agwani, Suhail; Domer, Steve; Rubacha, Ray; Stanley, Scott

    1999-04-01

    This paper discusses the performance of a new VGA resolution color CMOS imager developed by Motorola on a 0.5micrometers /3.3V CMOS process. This fully integrated, high performance imager has on chip timing, control, and analog signal processing chain for digital imaging applications. The picture elements are based on 7.8micrometers active CMOS pixels that use pinned photodiodes for higher quantum efficiency and low noise performance. The image processing engine includes a bank of programmable gain amplifiers, line rate clamping for dark offset removal, real time auto white balancing, per column gain and offset calibration, and a 10 bit pipelined RSD analog to digital converter with a programmable input range. Post ADC signal processing includes features such as bad pixel replacement based on user defined thresholds levels, 10 to 8 bit companding and 5 tap FIR filtering. The sensor can be programmed via a standard I2C interface that runs on 3.3V clocks. Programmable features include variable frame rates using a constant frequency master clock, electronic exposure control, continuous or single frame capture, progressive or interlace scanning modes. Each pixel is individually addressable allowing region of interest imaging and image subsampling. The sensor operates with master clock frequencies of up to 13.5MHz resulting in 30FPS. A total programmable gain of 27dB is available. The sensor power dissipation is 400mW at full speed of operation. The low noise design yields a measured 'system on a chip' dynamic range of 50dB thus giving over 8 true bits of resolution. Extremely high conversion gain result in an excellent peak sensitivity of 22V/(mu) J/cm2 or 3.3V/lux-sec. This monolithic image capture and processing engine represent a compete imaging solution making it a true 'camera on a chip'. Yet in its operation it remains extremely easy to use requiring only one clock and a 3.3V power supply. Given the available features and performance levels, this sensor will be

  13. Noise removal in nuclear medicine images by using multi resolution

    International Nuclear Information System (INIS)

    A novel flexible and dynamic algorithm for noise removal in nuclear medicine images is proposed. The images have a very low signal-to-noise ratio and the total number of registered photons is relatively small. The algorithm removes the noise from both the images original spatial domain and from the wavelet transform domain. In the spatial domain it uses both the autocorrelation technique in order to remove the noise that appears in a from of isolated pixels around the objects of interest and the information that each image contains about the signal in its neighbouring images. In the transform domain the wavelet coefficients filtration is carried out with a filter bank which meets the near-perfect reconstruction condition and is adapted to the signal. In addition, the coefficients that correspond to noise and are about to be discarded are selected by using a non uniform threshold which is adapted to the spatial varying noise level. Criteria for selection of an optimal decomposition level for the NM images are defined. In order to suppress the noise, multi resolution characteristics of both the signal and noise are used.(Author)

  14. High resolution imaging of dynamic surface processes from the ISS

    Science.gov (United States)

    Donnellan, A.; Green, J. J.; De Jong, E. M.; Knight, R.; Bills, B.; Arrowsmith, R.

    Spaceborne persistent multi-angle imaging allows staring at selected targets during an orbit pass. From its vantage point on the International Space Station (ISS) a persistent Earth imaging telescope would provide hundreds of high-resolution images simultaneously. Observations could be in visible and SWIR bands as it stares at a scene of interest. These images provide rich multi-angle stereo views enabling understanding of rapidly changing Earth features with many applications to Earth science and disaster response. Current academic state-of-the-art is driven by single images taken with a near nadir view. Persistent imaging could address NASA's goal of understanding how and why the Earth's environment is changing, and could be used for forecasting and mitigating the effects of natural disasters. Specifically such a mission could be used to answer the questions: 1) How are Earth's vulnerable systems reflecting changes in climate? and 2) What processes and features characterize the magnitude and extent of disasters? A mission would meet geomorphologists' requirements observing changing features such as landslides, earthquakes, floods, volcanoes, and glaciers.

  15. Imaging Analysis of the Hard X-ray Telescope ProtoEXIST2 and New Techniques for High Resolution Coded Aperture Telescopes

    CERN Document Server

    Hong, Jaesub; Grindlay, Jonathan; Barthelmy, Scott

    2016-01-01

    Wide-field (> 100 deg$^2$) hard X-ray coded-aperture telescopes with high angular resolution (< 2') will enable a wide range of time domain astrophysics. For instance, transient sources such as gamma-ray bursts can be precisely localized without assistance of secondary focusing X-ray telescopes to enable rapid followup studies. On the other hand, high angular resolution in coded-aperture imaging introduces a new challenge in handling the systematic uncertainty: average photon count per pixel is often too small to establish a proper background pattern or model the systematic uncertainty in a time scale where the model remains invariant. We introduce two new techniques to improve detection sensitivity, which are designed for, but not limited to high resolution coded-aperture system: a self-background modeling scheme which utilizes continuous scan or dithering operations, and a Poisson-statistics based probabilistic approach to evaluate the significance of source detection without subtraction in handling the ...

  16. Hybrid averaging offers high-flow contrast by cost apportionment among imaging time, axial, and lateral resolution in optical coherence tomography angiography.

    Science.gov (United States)

    Li, Peng; Cheng, Yuxuan; Li, Pei; Zhou, Liping; Ding, Zhihua; Ni, Yang; Pan, Cong

    2016-09-01

    The current temporal, wavelength, angular, and spatial averaging approaches trade imaging time and resolution for multiple independent measurements that improve the flow contrast in optical coherence tomography angiography (OCTA). We find that these averaging approaches are equivalent in principle, offering almost the same flow contrast enhancement as the number of averages increases. Based on this finding, we propose a hybrid averaging strategy for contrast enhancement by cost apportionment. We demonstrate that, compared with any individual approach, the hybrid averaging is able to offer a desired flow contrast without severe degradation of imaging time and resolution. Making use of the extended range of a VCSEL-based swept-source OCT, an angular averaging approach by path length encoding is also demonstrated for flow contrast enhancement. PMID:27607943

  17. A High Resolution Color Image Restoration Algorithm for Thin TOMBO Imaging Systems

    Directory of Open Access Journals (Sweden)

    Amar A. El-Sallam

    2009-06-01

    Full Text Available In this paper, we present a blind image restoration algorithm to reconstruct a high resolution (HR color image from multiple, low resolution (LR, degraded and noisy images captured by thin (< 1mm TOMBO imaging systems. The proposed algorithm is an extension of our grayscale algorithm reported in [1] to the case of color images. In this color extension, each Point Spread Function (PSF of each captured image is assumed to be different from one color component to another and from one imaging unit to the other. For the task of image restoration, we use all spectral information in each captured image to restore each output pixel in the reconstructed HR image, i.e., we use the most efficient global category of point operations. First, the composite RGB color components of each captured image are extracted. A blind estimation technique is then applied to estimate the spectra of each color component and its associated blurring PSF. The estimation process is formed in a way that minimizes significantly the interchannel cross-correlations and additive noise. The estimated PSFs together with advanced interpolation techniques are then combined to compensate for blur and reconstruct a HR color image of the original scene. Finally, a histogram normalization process adjusts the balance between image color components, brightness and contrast. Simulated and experimental results reveal that the proposed algorithm is capable of restoring HR color images from degraded, LR and noisy observations even at low Signal-to-Noise Energy ratios (SNERs. The proposed algorithm uses FFT and only two fundamental image restoration constraints, making it suitable for silicon integration with the TOMBO imager.

  18. A dedicated high resolution PET imager for plant sciences

    CERN Document Server

    Wang, Qiang; Li, Ke; Wen, Jie; Komarov, Sergey; O'Sullivan, Joseph A; Tai, Yuan-Chuan

    2014-01-01

    PET provides in vivo molecular and functional imaging capability that is crucial to studying the interaction of plant with changing environment at the whole-plant level. We have developed a dedicated plant PET imager that features high spatial resolution, housed in a fully controlled environment provided by a plant growth chamber (PGC). The system currently contains two types of detector modules: 84 microPET R4 block detectors with 2.2 mm crystals to provide a large detecting area; and 32 Inveon block detectors with 1.5 mm crystals to provide higher spatial resolution. Outputs of the four microPET block detectors in a modular housing are concatenated by a custom printed circuit board to match the output characteristics of an Inveon detector. All the detectors are read out by QuickSilver electronics. The detector modules are configured to full rings with a 15 cm diameter trans-axial field of view (FOV) for dynamic tomographic imaging of small plants. Potentially, the Inveon detectors can be reconfigured to qua...

  19. High-resolution panoramic images with megapixel MWIR FPA

    Science.gov (United States)

    Leboucher, Vincent; Aubry, Gilles

    2014-06-01

    In the continuity of its current strategy, HGH maintains a deep effort in developing its most recent product family: the infrared (IR) panoramic 360-degree surveillance sensors. During the last two years, HGH optimized its prototype Middle Wave IR (MWIR) panoramic sensor IR Revolution 360 HD that gave birth to Spynel-S product. Various test campaigns proved its excellent image quality. Cyclope, the software associated with Spynel, benefitted from recent image processing improvements and new functionalities such as target geolocalization, long range sensor slue to cue and facilitated forensics analysis. In the frame of the PANORAMIR project sustained by the DGA (Délégation Générale de l'Armement), HGH designed a new extra large resolution sensor including a MWIR megapixel Focal Plane Array (FPA) detector (1280×1024 pixels). This new sensor is called Spynel-X. It provides outstanding resolution 360-degree images (with more than 100 Mpixels). The mechanical frame of Spynel (-S and -X) was designed with the collaboration of an industrial design agency. Spynel got the "Observeur du Design 2013" label.

  20. ICORE: Image Co-addition with Optional Resolution Enhancement

    CERN Document Server

    Masci, Frank

    2013-01-01

    ICORE is a command-line driven co-addition, mosaicking and resolution enhancement (HiRes) tool for creating science quality products from image data in FITS format and with World Coordinate System information following the FITS-WCS standard. It includes preparatory steps such as image background matching, photometric gain-matching, and pixel-outlier rejection. Co-addition and/or HiRes'ing can be performed in either the inertial WCS, or in the rest frame of a moving object. Three interpolation methods are supported: overlap-area weighting, drizzle, and weighting by the detector Point Response Function (PRF). The latter enables the creation of matched-filtered products for optimal point-source detection, but most importantly allows for resolution enhancement using a spatially-dependent deconvolution method. This is a variant of the classic Richardson-Lucy algorithm with the added benefit to simultaneously register and co-add multiple images to optimize signal-to-noise and sampling of the instrumental PSF. It ca...

  1. Imaging protein interactions in vivo with sub-cellular resolution

    CERN Document Server

    Raicu, Valerica; Fung, Russell; Melnichuk, Mike; Jansma, David B; Pisterzi, Luca; Fox, Michael; Wells, James W; Saldin, Dilano K

    2008-01-01

    Resonant Energy Transfer (RET) from an optically excited donor molecule (D) to a non-excited acceptor molecule (A) residing nearby is widely used to detect molecular interactions in living cells. Stoichiometric information, such as the number of proteins forming a complex, has been obtained so far for a handful of proteins, but only after exposing the sample sequentially to at least two different excitation wavelengths. During this lengthy process of measurement, the molecular makeup of a cellular region may change, and this has so far limited the applicability of RET to determination of cellular averages. Here we demonstrate a method for imaging protein complex distribution in living cells with sub-cellular spatial resolution, which relies on a spectrally-resolved two-photon microscope, a simple but competent theory, and a keen selection of fluorescent tags. This technology may eventually lead to tracking dynamics of macromolecular complex formation and dissociation with spatial resolution inside living cell...

  2. High-resolution multiphoton imaging of tumors in vivo.

    Science.gov (United States)

    Wyckoff, Jeffrey; Gligorijevic, Bojana; Entenberg, David; Segall, Jeffrey; Condeelis, John

    2011-10-01

    Analysis of the individual steps in metastasis is crucial if insights at the molecular level are to be linked to the cell biology of cancer. A technical hurdle to achieving the analysis of the individual steps of metastasis is the fact that, at the gross level, tumors are heterogeneous in both animal models and patients. Human primary tumors show extensive variation in all properties ranging from growth and morphology of the tumor through tumor-cell density in the blood and formation and growth of metastases. Methods capable of the direct visualization and analysis of tumor-cell behavior at single-cell resolution in vivo have become crucial in advancing the understanding of mechanisms of metastasis, the definition of microenvironment, and the markers related to both. This article discusses the use of high-resolution multiphoton imaging of tumors (specifically breast tumors in mice) in vivo.

  3. MUSIC electromagnetic imaging with enhanced resolution for small inclusions

    International Nuclear Information System (INIS)

    This paper investigates the influence of the test dipole on the resolution of the multiple signal classification (MUSIC) imaging method applied to the electromagnetic inverse scattering problem of determining the locations of a collection of small objects embedded in a known background medium. Based on the analysis of the induced electric dipoles in eigenstates, an algorithm is proposed to determine the test dipole that generates a pseudo-spectrum with enhanced resolution. The amplitudes in three directions of the optimal test dipole are not necessarily in phase, i.e., the optimal test dipole may not correspond to a physical direction in the real three-dimensional space. In addition, the proposed test-dipole-searching algorithm is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC does not apply

  4. MUSIC electromagnetic imaging with enhanced resolution for small inclusions

    Science.gov (United States)

    Chen, Xudong; Zhong, Yu

    2009-01-01

    This paper investigates the influence of the test dipole on the resolution of the multiple signal classification (MUSIC) imaging method applied to the electromagnetic inverse scattering problem of determining the locations of a collection of small objects embedded in a known background medium. Based on the analysis of the induced electric dipoles in eigenstates, an algorithm is proposed to determine the test dipole that generates a pseudo-spectrum with enhanced resolution. The amplitudes in three directions of the optimal test dipole are not necessarily in phase, i.e., the optimal test dipole may not correspond to a physical direction in the real three-dimensional space. In addition, the proposed test-dipole-searching algorithm is able to deal with some special scenarios, due to the shapes and materials of objects, to which the standard MUSIC does not apply.

  5. A high-resolution radio image of a young supernova

    International Nuclear Information System (INIS)

    Supernovae in our own Galaxy are so rare that images of their remnants can show only the late aftermath of an explosion that occurred anything from a few hundred to several tens of thousands of years ago. Young supernovae are seen frequently in other galaxies, but because they are more distant it has not been possible until now to obtain high-resolution images that would reveal details of the explosion and the immediate development of the ejected material. Here we present a very-long-baseline interferometric (VLBI) radio image of the bright supernova 1986J, which occurred in the galaxy NGC891 at a distance of ∼12 Mpc. No detailed image of any supernova or remnant has been obtained before so soon after the explosion. Our image shows a shell of emission with jet-like protrusions. Their analysis should advance our understanding of the dynamics of the expanding debris, the dissipation of energy into the surrounding circumstellar medium, and the evolution of the supernova into the remnant. (author)

  6. A high-resolution radio image of a young supernova

    Energy Technology Data Exchange (ETDEWEB)

    Bartel, N.; Rupen, M.P.; Shapiro, I.I. (Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (USA)); Preston, R.A. (Jet Propulsion Lab., Pasadena, CA (USA)); Rius, A. (Universidad Complutense de Madrid (Spain). Inst. de Astronomia y Geodesia)

    1991-03-21

    Supernovae in our own Galaxy are so rare that images of their remnants can show only the late aftermath of an explosion that occurred anything from a few hundred to several tens of thousands of years ago. Young supernovae are seen frequently in other galaxies, but because they are more distant it has not been possible until now to obtain high-resolution images that would reveal details of the explosion and the immediate development of the ejected material. Here we present a very-long-baseline interferometric (VLBI) radio image of the bright supernova 1986J, which occurred in the galaxy NGC891 at a distance of {similar to}12 Mpc. No detailed image of any supernova or remnant has been obtained before so soon after the explosion. Our image shows a shell of emission with jet-like protrusions. Their analysis should advance our understanding of the dynamics of the expanding debris, the dissipation of energy into the surrounding circumstellar medium, and the evolution of the supernova into the remnant. (author).

  7. A Frequency Domain Approach to Registration of Aliased Images with Application to Super-resolution

    Directory of Open Access Journals (Sweden)

    Vandewalle Patrick

    2006-01-01

    Full Text Available Super-resolution algorithms reconstruct a high-resolution image from a set of low-resolution images of a scene. Precise alignment of the input images is an essential part of such algorithms. If the low-resolution images are undersampled and have aliasing artifacts, the performance of standard registration algorithms decreases. We propose a frequency domain technique to precisely register a set of aliased images, based on their low-frequency, aliasing-free part. A high-resolution image is then reconstructed using cubic interpolation. Our algorithm is compared to other algorithms in simulations and practical experiments using real aliased images. Both show very good visual results and prove the attractivity of our approach in the case of aliased input images. A possible application is to digital cameras where a set of rapidly acquired images can be used to recover a higher-resolution final image.

  8. Precision cosmology with time delay lenses: High resolution imaging requirements

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Xiao -Lei [Beijing Normal Univ., Beijing (China); Univ. of California, Santa Barbara, CA (United States); Treu, Tommaso [Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Agnello, Adriano [Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Auger, Matthew W. [Univ. of Cambridge, Cambridge (United Kingdom); Liao, Kai [Beijing Normal Univ., Beijing (China); Univ. of California, Santa Barbara, CA (United States); Univ. of California, Los Angeles, CA (United States); Marshall, Philip J. [Stanford Univ., Stanford, CA (United States)

    2015-09-28

    Lens time delays are a powerful probe of cosmology, provided that the gravitational potential of the main deflector can be modeled with sufficient precision. Recent work has shown that this can be achieved by detailed modeling of the host galaxies of lensed quasars, which appear as ``Einstein Rings'' in high resolution images. The distortion of these arcs and counter-arcs, as measured over a large number of pixels, provides tight constraints on the difference between the gravitational potential between the quasar image positions, and thus on cosmology in combination with the measured time delay. We carry out a systematic exploration of the high resolution imaging required to exploit the thousands of lensed quasars that will be discovered by current and upcoming surveys with the next decade. Specifically, we simulate realistic lens systems as imaged by the Hubble Space Telescope (HST), James Webb Space Telescope (JWST), and ground based adaptive optics images taken with Keck or the Thirty Meter Telescope (TMT). We compare the performance of these pointed observations with that of images taken by the Euclid (VIS), Wide-Field Infrared Survey Telescope (WFIRST) and Large Synoptic Survey Telescope (LSST) surveys. We use as our metric the precision with which the slope γ' of the total mass density profile ρtot∝ r–γ' for the main deflector can be measured. Ideally, we require that the statistical error on γ' be less than 0.02, such that it is subdominant to other sources of random and systematic uncertainties. We find that survey data will likely have sufficient depth and resolution to meet the target only for the brighter gravitational lens systems, comparable to those discovered by the SDSS survey. For fainter systems, that will be discovered by current and future surveys, targeted follow-up will be required. Furthermore, the exposure time required with upcoming facilitites such as JWST, the Keck Next Generation Adaptive

  9. Real-time imaging of spin-to-orbital angular momentum hybrid remote state preparation

    Science.gov (United States)

    Erhard, Manuel; Qassim, Hammam; Mand, Harjaspreet; Karimi, Ebrahim; Boyd, Robert W.

    2015-08-01

    There exists two prominent methods to transfer information between two spatially separated parties, namely Alice (A) and Bob (B): quantum teleportation and remote state preparation. However, the difference between these methods is, in the teleportation scheme, the state to be transferred is completely unknown, whereas in state preparation it should be known to the sender. In addition, photonic state teleportation is probabilistic due to the impossibility of performing a two-particle complete Bell-state analysis with linear optics, while remote state preparation can be performed deterministically. Here we report the first realization of photonic hybrid remote state preparation from spin to orbital angular momentum degrees of freedom. In our scheme, the polarization state of photon A is transferred to orbital angular momentum of photon B. The prepared states are visualized in real time by means of an intensified CCD camera. The quality of the prepared states is verified by performing quantum state tomography, which confirms an average fidelity higher than 99.4%. We believe that this experiment paves the way towards a novel means of quantum communication in which encryption and decryption are carried out in naturally different Hilbert spaces, and therefore may provide a means for enhancing security.

  10. Volcano structure in atomic resolution core-loss images

    Energy Technology Data Exchange (ETDEWEB)

    D' Alfonso, A.J.; Findlay, S.D. [School of Physics, University of Melbourne, Victoria, 3010 (Australia); Oxley, M.P. [Materials Science and Technology Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831 (United States); Allen, L.J. [School of Physics, University of Melbourne, Victoria, 3010 (Australia)], E-mail: lja@physics.unimelb.edu.au

    2008-06-15

    A feature commonly present in simulations of atomic resolution electron energy loss spectroscopy images in the scanning transmission electron microscope is the volcano or donut structure. In the past this has been understood in terms of a geometrical perspective using a dipole approximation. It is shown that the dipole approximation for core-loss spectroscopy begins to break down as the probe forming aperture semi-angle increases, necessitating the inclusion of higher order terms for a quantitative understanding of volcano formation. Using such simulations we further investigate the mechanisms behind the formation of such structures in the single atom case and extend this to the case of crystals. The cubic SrTiO{sub 3} crystal is used as a test case to show the effects of nonlocality, probe channelling and absorption in producing the volcano structure in crystal images.

  11. Feature Recognition of Low-resolution Fiber Image

    Institute of Scientific and Technical Information of China (English)

    YU Su-ping; ZENG Pei-feng; WU Xiong-ying; CHEN Jian-ping

    2006-01-01

    The interpolatory edge operator is applied to the recognition of cotton and ramie fibers. Its performance is studied in comparison with the Canny edge operator in the fiber's edge detection for cross-sectional image. The input image is interpolated other than Gaussian function smoothing. The quality of edge output is improved by the interpolatory edge operator. It produces edge output with good continuity for low-resolution input. The fine edge output, such as crossmarkings, can be distinguished clearly, so the interpolatory edge operator is suitable for the study of cotton and ramie fibers. Furthermore, the application of the interpolatory edge operator can cut the hardware cost, reduce the storage and speed up the data transmission.

  12. High-resolution imaging methods in array signal processing

    DEFF Research Database (Denmark)

    Xenaki, Angeliki

    in active sonar signal processing for detection and imaging of submerged oil contamination in sea water from a deep-water oil leak. The submerged oil _eld is modeled as a uid medium exhibiting spatial perturbations in the acoustic parameters from their mean ambient values which cause weak scattering......The purpose of this study is to develop methods in array signal processing which achieve accurate signal reconstruction from limited observations resulting in high-resolution imaging. The focus is on underwater acoustic applications and sonar signal processing both in active (transmit and receive......-of-arrival (DOA) of the associated wavefronts from a limited number of observations. Usually, there are only a few sources generating the acoustic wavefield such that DOA estimation is essentially a sparse signal reconstruction problem. Conventional methods for DOA estimation (i.e., beamforming) suffer from...

  13. Enhancement of Spatial Resolution of the Lroc Wide Angle Camera Images

    Science.gov (United States)

    Mahanti, P.; Robinson, M. S.; Sato, H.; Awumah, A.; Henriksen, M.

    2016-06-01

    Image fusion, a popular method for resolution enhancement in Earth-based remote sensing studies involves the integration of geometric (sharpness) detail of a high-resolution panchromatic (Pan) image and the spectral information of a lower resolution multi-spectral (MS) image. Image fusion with planetary images is not as widespread as with terrestrial studies, although successful application of image fusion can lead to the generation of higher resolution MS image data. A comprehensive comparison of six image fusion algorithms in the context of lunar images is presented in this work. Performance of these algorithms is compared by visual inspection of the high-resolution multi-spectral products, derived products such as band-to-band ratio and composite images, and performance metrics with an emphasis on spectral content preservation. Enhanced MS images of the lunar surface can enable new science and maximize the science return for current and future missions.

  14. Algorithm for Soybean Classification Using Medium Resolution Satellite Images

    Directory of Open Access Journals (Sweden)

    Anibal Gusso

    2012-10-01

    Full Text Available An accurate estimation of soybean crop areas while the plants are still in the field is highly necessary for reliable calculation of real crop parameters as to yield, production and other data important to decision-making policies related to government planning. An algorithm for soybean classification over the Rio Grande do Sul State, Brazil, was developed as an objective, automated tool. It is based on reflectance from medium spatial resolution images. The classification method was called the RCDA (Reflectance-based Crop Detection Algorithm, which operates through a mathematical combination of multi-temporal optical reflectance data obtained from Landsat-5 TM images. A set of 39 municipalities was analyzed for eight crop years between 1996/1997 and 2009/2010. RCDA estimates were compared to the official estimates of the Brazilian Institute of Geography and Statistics (IBGE for soybean area at a municipal level. Coefficients R2 were between 0.81 and 0.98, indicating good agreement of the estimates. The RCDA was also compared to a soybean crop map derived from Landsat images for the 2000/2001 crop year, the overall map accuracy was 91.91% and the Kappa Index of Agreement was 0.76. Due to the calculation chain and pre-defined parameters, RCDA is a timesaving procedure and is less subjected to analyst skills for image interpretation. Thus, the RCDA was considered advantageous to provide thematic soybean maps at local and regional scales.

  15. An extension of the high-resolution millimeter- and submillimeter-wave spectrum of methanol to high angular momentum quantum numbers

    Science.gov (United States)

    Anderson, Todd; Herbst, Eric; De Lucia, Frank C.

    1992-01-01

    The high-resolution laboratory millimeter- and submillimeter-wave spectra of C-12H(3)OH and C-13H(3)OH have been extended to include transitions involving significantly higher angular momentum quantum numbers than studied previously. For C-12H(3)OH, the data set now includes 549 A torsional substate transitions and 524 E torsional substate transitions through J is not greater than 24, exclusive of blends. For C-13H(3)OH the data set now includes 453 A torsional substate transitions and 440 E torsional substate transitions through J is not greater than 24, exclusive of blends. The extended internal axis method Hamiltonian has been used to analyze the transitions to experimental accuracy. The molecular constants determined by this approach have been used to predict accurately the frequencies of many transitions through J = 25 not measured in the laboratory.

  16. Towards continualized task-based resolution modeling in PET imaging

    Science.gov (United States)

    Ashrafinia, Saeed; Karakatsanis, Nicolas; Mohy-ud-Din, Hassan; Rahmim, Arman

    2014-03-01

    We propose a generalized resolution modeling (RM) framework, including extensive task-based optimization, wherein we continualize the conventionally discrete framework of RM vs. no RM, to include varying degrees of RM. The proposed framework has the advantage of providing a trade-off between the enhanced contrast recovery by RM and the reduced inter-voxel correlations in the absence of RM, and to enable improved task performance. The investigated context was that of oncologic lung FDG PET imaging. Given a realistic blurring kernel of FWHM h (`true PSF'), we performed iterative EM including RM using a wide range of `modeled PSF' kernels with varying widths h. In our simulations, h = 6mm, while h varied from 0 (no RM) to 12mm, thus considering both underestimation and overestimation of the true PSF. Detection task performance was performed using prewhitened (PWMF) and nonprewhitened matched filter (NPWMF) observers. It was demonstrated that an underestimated resolution blur (h = 4mm) enhanced task performance, while slight over-estimation (h = 7mm) also achieved enhanced performance. The latter is ironically attributed to the presence of ringing artifacts. Nonetheless, in the case of the NPWMF, the increasing intervoxel correlations with increasing values of h degrade detection task performance, and underestimation of the true PSF provides the optimal task performance. The proposed framework also achieves significant improvement of reproducibility, which is critical in quantitative imaging tasks such as treatment response monitoring.

  17. High resolution mm-VLBI imaging of Cygnus A

    CERN Document Server

    Boccardi, Bia; Bach, Uwe; Ros, Eduardo; Zensus, J Anton

    2015-01-01

    At a distance of 249 Mpc ($z$=0.056), Cygnus A is the only powerful FR II radio galaxy for which a detailed sub-parsec scale imaging of the base of both jet and counter-jet can be obtained. Observing with VLBI at millimeter wavelengths is fundamental for this object, as it uncovers those regions which appear self-absorbed or free-free absorbed by a circumnuclear torus at longer wavelengths. We performed 7 mm Global VLBI observations, achieving ultra-high resolution imaging on scales down to 90 $\\mu$as. This resolution corresponds to a linear scale of only $\\sim$400 Schwarzschild radii. We studied the transverse structure of the jets through a pixel-based analysis, and kinematic properties of the main emission features by modeling the interferometric visibilities with two-dimensional Gaussian components. Both jets appear limb-brightened, and their opening angles are relatively large ($\\phi_\\mathrm {j}\\sim 10^{\\circ}$). The flow is observed to accelerate within the inner-jet up to scales of $\\sim$1 pc, while lo...

  18. CARMENES input catalogue of M dwarfs II. High-resolution imaging with FastCam

    CERN Document Server

    Cortes-Contreras, M; Caballero, J A; Gauza, B; Montes, D; Alonso-Floriano, F J; Jeffers, S V; Morales, J C; Reiners, A; Ribas, I; Schoefer, P; Quirrenbach, A; Amado, P J; Mundt, R; Seifert, W

    2016-01-01

    Aims: We search for low-mass companions of M dwarfs and characterize their multiplicity fraction with the purpose of helping in the selection of the most appropriate targets for the CARMENES exoplanet survey. Methods: We obtained high-resolution images in the I band with the lucky imaging instrument FastCam at the 1.5 m Telescopio Carlos Sanchez for 490 mid- to late-M dwarfs. For all the detected binaries, we measured angular separations, position angles, and magnitude differences in the I band. We also calculated the masses of each individual component and estimated orbital periods, using the available magnitude and colour relations for M dwarfs and our own MJ-spectral type and mass-MI relations. To avoid biases in our sample selection, we built a volume-limited sample of M0.0-M5.0 dwarfs that is complete up to 86% within 14 pc. Results: From the 490 observed stars, we detected 80 companions in 76 systems, of which 30 are new discoveries. The multiplicity fraction in our observed sample is 16.7+-2.0% . In ou...

  19. High-resolution Imaging of Living Retina through Optic Adaptive Retinal Imaging System

    Institute of Scientific and Technical Information of China (English)

    Chunhui Jiang; Wenji Wang; Ning Ling; Gezhi Xu; Xuejun Rao; Xinyang Li; Yudong Zhang

    2002-01-01

    Purpose: To evaluate the possibility as well as the usage of adaptive optics in high-resolution retinal imaging.Methods:From March to November 2001, the fundus of 25 adults were checked by using Optic Adaptive Retinal Imaging System (OAS). The age of the subjects varied from 18~48 years. All had normal visual acuity from 0.9 to 1.0. No abnormality was found in the ocular examination, and their medical as well as ocular history was unremarkable. Results: High-resolution images of the retinal cells, photoreceptor and bipolar cell, were analysed. In these images, the cells are clearly resolved. The density of the photoreceptor at area 1.5 degree from the foveloa is around 40 000~50 000/mm2. At area 3 degree, it drops to less than 30 000/mm2.Conclusion:Optic Adaptive Retinal Imaging System (AOS) is able to get high-resolution image of retinal cells in living human eyes. It may be widely used in ophthalmology experimentally and clinically.

  20. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    OpenAIRE

    Libo Wang; Lianlin Li; Yunbo Li; Hao Chi Zhang; Tie Jun Cui

    2016-01-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since ...

  1. High Resolution Depth-Resolved Imaging From Multi-Focal Images for Medical Ultrasound

    DEFF Research Database (Denmark)

    Diamantis, Konstantinos; Dalgarno, Paul A.; Greenaway, Alan H.;

    2015-01-01

    in-focus images. The technique is derived from biological microscopy and is validated here with simulated ultrasound data. A linear array probe is used to scan a point scatterer phantom that moves in depth with a controlled step. From the beamformed responses of each scatterer position the image......An ultrasound imaging technique providing subdiffraction limit axial resolution for point sources is proposed. It is based on simultaneously acquired multi-focal images of the same object, and on the image metric of sharpness. The sharpness is extracted by image data and presents higher values for...... sharpness is assessed. Values from all positions plotted together form a curve that peaks at the receive focus, which is set during the beamforming. Selection of three different receive foci for each acquired dataset will result in the generation of three overlapping sharpness curves. A set of three...

  2. Fast Super-Resolution Imaging with Ultra-High Labeling Density Achieved by Joint Tagging Super-Resolution Optical Fluctuation Imaging (JT-SOFI)

    CERN Document Server

    Zeng, Zhiping; Wang, Hening; Huang, Ning; Shan, Chunyan; Zhang, Hao; Teng, Junlin; Xi, Peng

    2015-01-01

    Previous stochastic localization-based super-resolution techniques are largely limited by the labeling density and the fidelity to the morphology of specimen. We report on an optical super-resolution imaging scheme implementing joint tagging using multiple fluorescent blinking dyes associated with super-resolution optical fluctuation imaging (JT-SOFI), achieving ultra-high labeling density super-resolution imaging. To demonstrate the feasibility of JT-SOFI, quantum dots with different emission spectra were jointly labeled to the tubulin in COS7 cells, creating ultra-high density labeling. After analyzing and combining the fluorescence intermittency images emanating from spectrally resolved quantum dots, the microtubule networks are capable of being investigated with high fidelity and remarkably enhanced contrast at sub-diffraction resolution. The spectral separation also significantly decreased the frame number required for SOFI, enabling fast super-resolution microscopy through simultaneous data acquisition....

  3. Overcoming Registration Uncertainty in Image Super-Resolution: Maximize or Marginalize?

    Directory of Open Access Journals (Sweden)

    Andrew Zisserman

    2007-01-01

    Full Text Available In multiple-image super-resolution, a high-resolution image is estimated from a number of lower-resolution images. This usually involves computing the parameters of a generative imaging model (such as geometric and photometric registration, and blur and obtaining a MAP estimate by minimizing a cost function including an appropriate prior. Two alternative approaches are examined. First, both registrations and the super-resolution image are found simultaneously using a joint MAP optimization. Second, we perform Bayesian integration over the unknown image registration parameters, deriving a cost function whose only variables of interest are the pixel values of the super-resolution image. We also introduce a scheme to learn the parameters of the image prior as part of the super-resolution algorithm. We show examples on a number of real sequences including multiple stills, digital video, and DVDs of movies.

  4. Production of High-Resolution Remote Sensing Images for Navigation Information Infrastructures

    Institute of Scientific and Technical Information of China (English)

    WANG Zhijun; Djemel Ziou; Costas Armenakis

    2004-01-01

    This paper introduces the image fusion approach of multi-resolution analysis-based intensity modulation (MRAIM) to produce the high-resolution multi-spectral images from high-resolution panchromatic image and low-resolution multi-spectral images for navigation information infrastructure. The mathematical model of image fusion is derived according to the principle of remote sensing image formation. It shows that the pixel values of a high-resolution multi-spectral images are determined by the pixel values of the approximation of a high-resolution panchromatic image at the resolution level of low-resolution multi-spectral images, and in the pixel valae computation the M-band wavelet theory and the à trous algorithm are then used. In order to evaluate the MRAIM approach, an experiment has been carried out on the basis of the IKONOS 1 m panchromatic image and 4 m multi-spectral images. The result demonstrates that MRAIM image fusion approach gives promising fusion results and it can be used to produce the high-resolution remote sensing images required for navigation information infrastructures.

  5. First-order convex feasibility algorithms for iterative image reconstruction in limited angular-range X-ray CT

    CERN Document Server

    Sidky, Emil Y; Pan, Xiaochuan

    2012-01-01

    Iterative image reconstruction (IIR) algorithms in Computed Tomography (CT) are based on algorithms for solving a particular optimization problem. Design of the IIR algorithm, therefore, is aided by knowledge of the solution to the optimization problem on which it is based. Often times, however, it is impractical to achieve accurate solution to the optimization of interest, which complicates design of IIR algorithms. This issue is particularly acute for CT with a limited angular-range scan, which leads to poorly conditioned system matrices and difficult to solve optimization problems. In this article, we develop IIR algorithms which solve a certain type of optimization called convex feasibility. The convex feasibility approach can provide alternatives to unconstrained optimization approaches and at the same time allow for efficient algorithms for their solution -- thereby facilitating the IIR algorithm design process. An accelerated version of the Chambolle-Pock (CP) algorithm is adapted to various convex fea...

  6. Ultra-low kinetic energy photoelectron angular distribution measurements in He and Ne using a Velocity Map Imaging spectrometer

    Science.gov (United States)

    Juarez, A. M.; Redt, E.; Hoenert, M.; Hoyos-Campo, L. M.; Rolles, D.; Berrah, N.; Aguilar, A.

    2009-11-01

    We present photoelectron angular distributions (PADs) in Helium and Neon for electrons with excess energies between 5 and 100 meV. These ultra-low kinetic energy PAD measurements were obtained with a modified Velocity Map Imaging spectrometer (VMI) and VUV light from the Advanced Light Source (ALS) synchrotron radiation source. The efficiency and reliability of the spectrometer at this ultra-low kinetic energy range has been tested by determining the variation with energy of the asymmetry, β, parameter of photoelectrons from the s-shell direct ionization in Helium. For Neon, we determined the energy dependent asymmetry parameters across the "s" and "d" autoionizing resonances between the P3/2 and P1/2 ionic states. Furthermore, we measured the asymmetry parameter for photoelectrons produced from the n = 2 to n = 6 satellite states of He. These measurements were performed at values of excess kinetic energy previously unexplored.

  7. Ultra-low kinetic energy photoelectron angular distribution measurements in He and Ne using a Velocity Map Imaging spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Juarez, A M; Hoyos-Campo, L M [Institute de Ciencias Fisicas, Universidad Nacional Autonoma de Mexico, Cuernavaca, Mor. 62210 (Mexico); Redt, E; Hoenert, M; Aguilar, A [Lawrence Berkeley National Laboratory, Berkeley CA-94720 (United States); Rolles, D [Max Planck Advanced Study Group, CFEL, D-22761 Hamburg (Germany); Berrah, N, E-mail: aaguilar@lbl.go [Department of Physics, Western Michigan University, Kalamazoo MI-49008 (United States)

    2009-11-01

    We present photoelectron angular distributions (PADs) in Helium and Neon for electrons with excess energies between 5 and 100 meV. These ultra-low kinetic energy PAD measurements were obtained with a modified Velocity Map Imaging spectrometer (VMI) and VUV light from the Advanced Light Source (ALS) synchrotron radiation source. The efficiency and reliability of the spectrometer at this ultra-low kinetic energy range has been tested by determining the variation with energy of the asymmetry, {beta}, parameter of photoelectrons from the s-shell direct ionization in Helium. For Neon, we determined the energy dependent asymmetry parameters across the 's' and 'd' autoionizing resonances between the P{sub 3/2} and P{sub 1/2} ionic states. Furthermore, we measured the asymmetry parameter for photoelectrons produced from the n = 2 to n = 6 satellite states of He. These measurements were performed at values of excess kinetic energy previously unexplored.

  8. Effects of frame rate and image resolution on pulse rate measured using multiple camera imaging photoplethysmography

    Science.gov (United States)

    Blackford, Ethan B.; Estepp, Justin R.

    2015-03-01

    Non-contact, imaging photoplethysmography uses cameras to facilitate measurements including pulse rate, pulse rate variability, respiration rate, and blood perfusion by measuring characteristic changes in light absorption at the skin's surface resulting from changes in blood volume in the superficial microvasculature. Several factors may affect the accuracy of the physiological measurement including imager frame rate, resolution, compression, lighting conditions, image background, participant skin tone, and participant motion. Before this method can gain wider use outside basic research settings, its constraints and capabilities must be well understood. Recently, we presented a novel approach utilizing a synchronized, nine-camera, semicircular array backed by measurement of an electrocardiogram and fingertip reflectance photoplethysmogram. Twenty-five individuals participated in six, five-minute, controlled head motion artifact trials in front of a black and dynamic color backdrop. Increasing the input channel space for blind source separation using the camera array was effective in mitigating error from head motion artifact. Herein we present the effects of lower frame rates at 60 and 30 (reduced from 120) frames per second and reduced image resolution at 329x246 pixels (one-quarter of the original 658x492 pixel resolution) using bilinear and zero-order downsampling. This is the first time these factors have been examined for a multiple imager array and align well with previous findings utilizing a single imager. Examining windowed pulse rates, there is little observable difference in mean absolute error or error distributions resulting from reduced frame rates or image resolution, thus lowering requirements for systems measuring pulse rate over sufficient length time windows.

  9. High resolution Ceres HAMO atlas derived from Dawn FC images

    Science.gov (United States)

    Roatsch, Thomas; Kersten, Elke; Matz, Klaus-Dieter; Preusker, Frank; Scholten, Frank; Jaumann, Ralf; Raymond, Carol A.; Russell, Chris T.

    2016-04-01

    Introduction: NASA's Dawn spacecraft entered the orbit of dwarf planet Ceres in March 2015, and will characterize the geology, elemental and mineralogical composition, topography, shape, and internal structure of Ceres. One of the major goals of the mission is a global mapping of Ceres. Data: The Dawn mission was mapping Ceres in HAMO (High Altitude Mapping Orbit, 1475 km altitude) between August and October 2015. The framing camera took about 2,600 clear filter images with a resolution of about 140 m/pixel during these cycles. The images were taken with different viewing angles and different illumination conditions. We selected images from one cycle (cycle #1) for the mosaicking process to have similar viewing and illumination conditions. Very minor gaps in the coverage were filled with a few images from cycle #2. Data Processing: The first step of the processing chain towards the cartographic products is to ortho-rectify the images to the proper scale and map projec-tion type. This process requires detailed information of the Dawn orbit and attitude data and of the topography of the targets. Both, improved orientation and a high-resolution shape model, are provided by stereo processing (bundle block adjustment) of the HAMO stereo image dataset [3]. Ceres's HAMO shape model was used for the calculation of the ray intersection points while the map projection itself was done onto the reference sphere of Ceres with a radius of 470 km. The final step is the controlled mosaicking) of all images to a global mosaic of Ceres, the so-called basemap. Ceres map tiles: The Ceres atlas was produced in a scale of 1:750,000 and consists of 15 tiles that conform to the quadrangle scheme proposed by Greeley and Batson [4]. A map scale of 1:750,000 guarantees a mapping at the highest available Dawn resolution in HAMO. The individual tiles were extracted from the global mosaic and reprojected. Nomenclature: The Dawn team proposed 81 names for geological features. By international

  10. High Resolution 3D Radar Imaging of Comet Interiors

    Science.gov (United States)

    Asphaug, E. I.; Gim, Y.; Belton, M.; Brophy, J.; Weissman, P. R.; Heggy, E.

    2012-12-01

    Knowing the interiors of comets and other primitive bodies is fundamental to our understanding of how planets formed. We have developed a Discovery-class mission formulation, Comet Radar Explorer (CORE), based on the use of previously flown planetary radar sounding techniques, with the goal of obtaining high resolution 3D images of the interior of a small primitive body. We focus on the Jupiter-Family Comets (JFCs) as these are among the most primitive bodies reachable by spacecraft. Scattered in from far beyond Neptune, they are ultimate targets of a cryogenic sample return mission according to the Decadal Survey. Other suitable targets include primitive NEOs, Main Belt Comets, and Jupiter Trojans. The approach is optimal for small icy bodies ~3-20 km diameter with spin periods faster than about 12 hours, since (a) navigation is relatively easy, (b) radar penetration is global for decameter wavelengths, and (c) repeated overlapping ground tracks are obtained. The science mission can be as short as ~1 month for a fast-rotating JFC. Bodies smaller than ~1 km can be globally imaged, but the navigation solutions are less accurate and the relative resolution is coarse. Larger comets are more interesting, but radar signal is unlikely to be reflected from depths greater than ~10 km. So, JFCs are excellent targets for a variety of reasons. We furthermore focus on the use of Solar Electric Propulsion (SEP) to rendezvous shortly after the comet's perihelion. This approach leaves us with ample power for science operations under dormant conditions beyond ~2-3 AU. This leads to a natural mission approach of distant observation, followed by closer inspection, terminated by a dedicated radar mapping orbit. Radar reflections are obtained from a polar orbit about the icy nucleus, which spins underneath. Echoes are obtained from a sounder operating at dual frequencies 5 and 15 MHz, with 1 and 10 MHz bandwidths respectively. The dense network of echoes is used to obtain global 3D

  11. Improved SOT (Hinode mission) high resolution solar imaging observations

    CERN Document Server

    Goodarzi, Hadis; Adjabshirizadeh, Ali

    2015-01-01

    We consider the best today available observations of the Sun free of turbulent Earth atmospheric effects, taken with the Solar Optical Telescope (SOT) onboard the Hinode spacecraft. Both the instrumental smearing and the observed stray light are analyzed in order to improve the resolution. The Point Spread Function (PSF) corresponding to the blue continuum Broadband Filter Imager (BFI) near 450 nm is deduced by analyzing i/ the limb of the Sun and ii/ images taken during the transit of the planet Venus in 2012. A combination of Gaussian and Lorentzian functions is selected to construct a PSF in order to remove both smearing due to the instrumental diffraction effects (PSF core) and the large-angle stray light due to the spiders and central obscuration (wings of the PSF) that are responsible for the parasitic stray light. A Max-likelihood deconvolution procedure based on an optimum number of iterations is discussed. It is applied to several solar field images, including the granulation near the limb. The norma...

  12. Structure recognition from high resolution images of ceramic composites

    Energy Technology Data Exchange (ETDEWEB)

    Ushizima, Daniela; Perciano, Talita; Krishnan, Harinarayan; Loring, Burlen; Bale, Hrishikesh; Parkinson, Dilworth; Sethian, James

    2015-01-05

    Fibers provide exceptional strength-to-weight ratio capabilities when woven into ceramic composites, transforming them into materials with exceptional resistance to high temperature, and high strength combined with improved fracture toughness. Microcracks are inevitable when the material is under strain, which can be imaged using synchrotron X-ray computed micro-tomography (mu-CT) for assessment of material mechanical toughness variation. An important part of this analysis is to recognize fibrillar features. This paper presents algorithms for detecting and quantifying composite cracks and fiber breaks from high-resolution image stacks. First, we propose recognition algorithms to identify the different structures of the composite, including matrix cracks and fibers breaks. Second, we introduce our package F3D for fast filtering of large 3D imagery, implemented in OpenCL to take advantage of graphic cards. Results show that our algorithms automatically identify micro-damage and that the GPU-based implementation introduced here takes minutes, being 17x faster than similar tools on a typical image file.

  13. Local orbital angular momentum revealed by spiral phase plate imaging in transmission electron microscopy

    CERN Document Server

    Juchtmans, Roeland

    2015-01-01

    The orbital angular momentum (OAM) of light and matter waves is a parameter that is getting increasingly more attention over the past couple of years. Beams with a well defined OAM, the so-called vortex beams, are applied already in e.g. telecommunication, astrophysics, nanomanipulation and chiral measurements in optics and electron microscopy. Also the OAM of a wave induced by the interaction with a sample, shows great potential of interest. In all these experiments it is crucial to measure the exact (local) OAM content of the wave, whether it is an incoming vortex beam or an exit wave after interacting with a sample. In this work we investigate the use of spiral phase plates as an alternative to the programmable phase plates used in optics to measure OAM. We derive analytically how these can be used to study the local OAM components of any wave function. By means of numerical simulations we illustrate how the OAM of a pure vortex beam can be measured. We also look at a sum of misaligned vortex beams and sho...

  14. A rapid and automated relocation method of an AFM probe for high-resolution imaging

    Science.gov (United States)

    Zhou, Peilin; Yu, Haibo; Shi, Jialin; Jiao, Niandong; Wang, Zhidong; Wang, Yuechao; Liu, Lianqing

    2016-09-01

    The atomic force microscope (AFM) is one of the most powerful tools for high-resolution imaging and high-precision positioning for nanomanipulation. The selection of the scanning area of the AFM depends on the use of the optical microscope. However, the resolution of an optical microscope is generally no larger than 200 nm owing to wavelength limitations of visible light. Taking into consideration the two determinants of relocation—relative angular rotation and positional offset between the AFM probe and nano target—it is therefore extremely challenging to precisely relocate the AFM probe to the initial scan/manipulation area for the same nano target after the AFM probe has been replaced, or after the sample has been moved. In this paper, we investigate a rapid automated relocation method for the nano target of an AFM using a coordinate transformation. The relocation process is both simple and rapid; moreover, multiple nano targets can be relocated by only identifying a pair of reference points. It possesses a centimeter-scale location range and nano-scale precision. The main advantages of this method are that it overcomes the limitations associated with the resolution of optical microscopes, and that it is label-free on the target areas, which means that it does not require the use of special artificial markers on the target sample areas. Relocation experiments using nanospheres, DNA, SWCNTs, and nano patterns amply demonstrate the practicality and efficiency of the proposed method, which provides technical support for mass nanomanipulation and detection based on AFM for multiple nano targets that are widely distributed in a large area.

  15. Hierarchical progressive surveys. Multi-resolution HEALPix data structures for astronomical images, catalogues, and 3-dimensional data cubes

    CERN Document Server

    Fernique, P; Boch, T; Oberto, A; Pineau, F-X; Durand, D; Bot, C; Cambresy, L; Derriere, S; Genova, F; Bonnarel, F

    2015-01-01

    Scientific exploitation of the ever increasing volumes of astronomical data requires efficient and practical methods for data access, visualisation, and analysis. Hierarchical sky tessellation techniques enable a multi-resolution approach to organising data on angular scales from the full sky down to the individual image pixels. Aims. We aim to show that the Hierarchical progressive survey (HiPS) scheme for describing astronomical images, source catalogues, and three-dimensional data cubes is a practical solution to managing large volumes of heterogeneous data and that it enables a new level of scientific interoperability across large collections of data of these different data types. Methods. HiPS uses the HEALPix tessellation of the sphere to define a hierarchical tile and pixel structure to describe and organise astronomical data. HiPS is designed to conserve the scientific properties of the data alongside both visualisation considerations and emphasis on the ease of implementation. We describe the develop...

  16. Study of fish response using particle image velocimetry and high-speed, high-resolution imaging

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Richmond, M. C. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Mueller, R. P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Gruensch, G. R. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2004-10-01

    Fish swimming has fascinated both engineers and fish biologists for decades. Digital particle image velocimetry (DPIV) and high-speed, high-resolution digital imaging are recently developed analysis tools that can help engineers and biologists better understand how fish respond to turbulent environments. This report details studies to evaluate DPIV. The studies included a review of existing literature on DPIV, preliminary studies to test the feasibility of using DPIV conducted at our Flow Biology Laboratory in Richland, Washington September through December 2003, and applications of high-speed, high-resolution digital imaging with advanced motion analysis to investigations of fish injury mechanisms in turbulent shear flows and bead trajectories in laboratory physical models. Several conclusions were drawn based on these studies, which are summarized as recommendations for proposed research at the end of this report.

  17. Investigation of Image Fusion Between High-Resolution Image and Multi-spectral Image

    Institute of Scientific and Technical Information of China (English)

    LI Pingxiang; WANG Zhijun

    2003-01-01

    On the basis of a thorough understanding of the physical characteristics of remote sensing image, this paper employs the theories of wavelet transform and signal sampling to develop a new image fusion algorithm. The algorithm has been successfully applied to the image fusion of SPOT PAN and TM of Guangdong province, China. The experimental results show that a perfect image fusion can be built up by using the image analytical solution and re-construction in the image frequency domain based on the physical characteristics of the image formation. The method has demonstrated that the results of the image fusion do not change spectral characteristics of the original image.

  18. Building identification from very high-resolution satellite images

    Science.gov (United States)

    Lhomme, Stephane

    Urbanisation still remains one of the main problems worldwide. The extent and rapidity of the urban growth induce a number of socio-economic and environmental conflicts everywhere. In order to reduce these problems, urban planners need to integrate spatial information in planning tools. Actually high expectations are made on Very High Spatial Resolution imagery (VHSR). These high-spatial resolution images are available at a reasonable price and due to short revisit periods, they offer a high degree of actuality. However, interpretation methods seem not to be adapted to this new type of images. The aim of our study is to develop a new method for semi-automatic building extraction with VHSR. The different steps performed to achieve our objective are each presented in a chapter. In the first chapter, the general context of our research is described with the definition of our objective. After a short historical review of urbanisation, we focus on urban growth and associated problems. In the following we discuss the possible contributions of geography to reduce these problems. After discussing concepts, theories and methodologies of geographical analysis in urban areas, we present existing general urban planning tools. Finally, we show the special interest of our study that is due to a growing need to integrate spatial information in these decision support tools. In the second chapter we verify the possibility of reaching our objective by analysing the technical characteristics of the images, the noise and the distortions which affect the images. Quality and interpretability of the studied image is analysed in order to show the capacity of these image to represent urban objects as close to reality as possible. The results confirm the potential of VHSR Imagery for urban objects analysis. The third chapter deal with the preliminary steps necessary for the elaboration of our method of building extraction. First, we evaluate the quality of the Sherbrooke Ikonos image

  19. Noncontact optical imaging in mice with full angular coverage and automatic surface extraction

    Science.gov (United States)

    Meyer, Heiko; Garofalakis, Anikitos; Zacharakis, Giannis; Psycharakis, Stylianos; Mamalaki, Clio; Kioussis, Dimitris; Economou, Eleftherios N.; Ntziachristos, Vasilis; Ripoll, Jorge

    2007-06-01

    During the past decade, optical imaging combined with tomographic approaches has proved its potential in offering quantitative three-dimensional spatial maps of chromophore or fluorophore concentration in vivo. Due to its direct application in biology and biomedicine, diffuse optical tomography (DOT) and its fluorescence counterpart, fluorescence molecular tomography (FMT), have benefited from an increase in devoted research and new experimental and theoretical developments, giving rise to a new imaging modality. The most recent advances in FMT and DOT are based on the capability of collecting large data sets by using CCDs as detectors, and on the ability to include multiple projections through recently developed noncontact approaches. For these to be implemented, we have developed an imaging setup that enables three-dimensional imaging of arbitrary shapes in fluorescence or absorption mode that is appropriate for small animal imaging. This is achieved by implementing a noncontact approach both for sources and detectors and coregistering surface geometry measurements using the same CCD camera. A thresholded shadowgrammetry approach is applied to the geometry measurements to retrieve the surface mesh. We present the evaluation of the system and method in recovering three-dimensional surfaces from phantom data and live mice. The approach is used to map the measured in vivo fluorescence data onto the tissue surface by making use of the free-space propagation equations, as well as to reconstruct fluorescence concentrations inside highly scattering tissuelike phantom samples. Finally, the potential use of this setup for in vivo small animal imaging and its impact on biomedical research is discussed.

  20. A Fast Algorithm for Image Super-Resolution from Blurred Observations

    Directory of Open Access Journals (Sweden)

    Ng Michael K

    2006-01-01

    Full Text Available We study the problem of reconstruction of a high-resolution image from several blurred low-resolution image frames. The image frames consist of blurred, decimated, and noisy versions of a high-resolution image. The high-resolution image is modeled as a Markov random field (MRF, and a maximum a posteriori (MAP estimation technique is used for the restoration. We show that with the periodic boundary condition, a high-resolution image can be restored efficiently by using fast Fourier transforms. We also apply the preconditioned conjugate gradient method to restore high-resolution images in the aperiodic boundary condition. Computer simulations are given to illustrate the effectiveness of the proposed approach.

  1. A Fast Super-Resolution Reconstruction from Image Sequence

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the mechanism of imagery, a novel method called the delaminating combining template method, used for the problem of super-resolution reconstruction from image sequence, is described in this paper. The combining template method contains two steps: a delaminating strategy and a combining template algorithm. The delaminating strategy divides the original problem into several sub-problems;each of them is only connected to one degrading factor. The combining template algorithm is suggested to resolve each sub-problem. In addition, to verify the valid of the method, a new index called oriental entropy is presented. The results from the theoretical analysis and experiments illustrate that this method to be promising and efficient.

  2. Monitoring of vegetation coverage based on high-resolution images

    Institute of Scientific and Technical Information of China (English)

    Zhang Li; Li Li-juan; Liang Li-qiao; Li Jiu-yi

    2007-01-01

    Measurement of vegetation coverage on a small scale is the foundation for the monitoring of changes in vegetation coverage and of the inversion model of monitoring vegetation coverage on a large scale by remote sensing. Using the object-oriented analytical software,Definiens Professional 5,a new method for calculating vegetation coverage based on high-resolution images(aerial photographs or near-surface photography)is proposed. Our research supplies references to remote sensing measurements of vegetation coverage on a small scale and accurate fundamental data for the inversion model of vegetation coverage on a large and intermediatc scale to improve the accuracy of remote sensing monitoring of changes in vegetation coverage.

  3. Mobile sensor for high resolution NMR spectroscopy and imaging

    Science.gov (United States)

    Danieli, Ernesto; Mauler, Jörg; Perlo, Juan; Blümich, Bernhard; Casanova, Federico

    2009-05-01

    In this work we describe the construction of a mobile NMR tomograph with a highly homogeneous magnetic field. Fast MRI techniques as well as NMR spectroscopy measurements were carried out. The magnet is based on a Halbach array built from identical permanent magnet blocks generating a magnetic field of 0.22 T. To shim the field inhomogeneities inherent to magnet arrays constructed from these materials, a shim strategy based on the use of movable magnet blocks is employed. With this approach a reduction of the line-width from ˜20 kHz to less than 0.1 kHz was achieved, that is by more than two orders of magnitude, in a volume of 21 cm 3. Implementing a RARE sequence, 3D images of different objects placed in this volume were obtained in short experimental times. Moreover, by reducing the sample size to 1 cm 3, sub ppm resolution is obtained in 1H NMR spectra.

  4. Local orbital angular momentum revealed by spiral-phase-plate imaging in transmission-electron microscopy

    Science.gov (United States)

    Juchtmans, Roeland; Verbeeck, Jo

    2016-02-01

    The orbital angular momentum (OAM) of light and matter waves is a parameter that has been getting increasingly more attention over the past couple of years. Beams with a well-defined OAM, the so-called vortex beams, are applied already in, e.g., telecommunication, astrophysics, nanomanipulation, and chiral measurements in optics and electron microscopy. Also, the OAM of a wave induced by the interaction with a sample has attracted a lot of interest. In all these experiments it is crucial to measure the exact (local) OAM content of the wave, whether it is an incoming vortex beam or an exit wave after interacting with a sample. In this work we investigate the use of spiral phase plates (SPPs) as an alternative to the programmable phase plates used in optics to measure OAM. We derive analytically how these can be used to study the local OAM components of any wave function. By means of numerical simulations we illustrate how the OAM of a pure vortex beam can be measured. We also look at a sum of misaligned vortex beams and show how, by using SPPs, the position and the OAM of each individual beam can be detected. Finally, we look at the OAM induced by a magnetic dipole on a free-electron wave and show how the SPP can be used to localize the magnetic poles and measure their "magnetic charge." Although our findings can be applied to study the OAM of any wave function, our findings are of particular interest for electron microscopy where versatile programmable phase plates do not yet exist.

  5. Characterization of a submillimeter high-angular-resolution camera with a monolithic silicon bolometer array for the Caltech Submillimeter Observatory

    OpenAIRE

    Wang, Nina; Hunter, T. R.; Benford, D. J.; Serabyn, E.; Lis, D.C.; Phillips, T. G.; Moseley, S. H.; Bpyce, K.; Szymkowiak, A.; C. Allen; Mott, B.; Gygax, J.

    1996-01-01

    We constructed a 24-pixel bolometer camera operating in the 350- and 450-µm atmospheric windows for the Caltech Submillimeter Observatory (CSO). This instrument uses a monolithic silicon bolometer array that is cooled to approximately 300 mK by a single-shot 3 He refrigerator. First-stage amplification is provided by field-effect transistors at approximately 130 K. The sky is imaged onto the bolometer array by means of several mirrors outside the Dewar and a cold off-axis elliptical mirror in...

  6. Wavelet-Based Mixed-Resolution Coding Approach Incorporating with SPT for the Stereo Image

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    With the advances of display technology, three-dimensional(3-D) imaging systems are becoming increasingly popular. One way of stimulating 3-D perception is to use stereo pairs, a pair of images of the same scene acquired from different perspectives. Since there is an inherent redundancy between the images of a stereo pairs, data compression algorithms should be employed to represent stereo pairs efficiently. The proposed techniques generally use blockbased disparity compensation. In order to get the higher compression ratio, this paper employs the wavelet-based mixed-resolution coding technique to incorporate with SPT-based disparity-compensation to compress the stereo image data. The mixed-resolution coding is a perceptually justified technique that is achieved by presenting one eye with a low-resolution image and the other with a high-resolution image. Psychophysical experiments show that the stereo image pairs with one high-resolution image and one low-resolution image provide almost the same stereo depth to that of a stereo image with two high-resolution images. By combining the mixed-resolution coding and SPT-based disparity-compensation techniques, one reference (left) high-resolution image can be compressed by a hierarchical wavelet transform followed by vector quantization and Huffman encoder. After two level wavelet decompositions, for the lowresolution right image and low-resolution left image, subspace projection technique using the fixed block size disparity compensation estimation is used. At the decoder, the low-resolution right subimage is estimated using the disparity from the low-resolution left subimage. A full-size reconstruction is obtained by upsampling a factor of 4 and reconstructing with the synthesis low pass filter. Finally, experimental results are presented, which show that our scheme achieves a PSNR gain (about 0.92dB) as compared to the current block-based disparity compensation coding techniques.``

  7. Providing stringent star formation rate limits of z$\\sim$2 QSO host galaxies at high angular resolution

    CERN Document Server

    Vayner, Andrey; Do, Tuan; Larkin, James E; Armus, Lee; Gallagher, Sarah C

    2014-01-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z=2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini-North Observatories using OSIRIS and NIFS coupled with the LGS-AO systems. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z=2.15. We demonstrate that the combination of AO and IFS provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a PSF from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy. We detect H$\\alpha$ and [NII] for two sources, SDSS J1029+6510 and SDSS J0925+06 that have both star formation and extended narrow-line emission. Assuming that the majority of narrow-line H$\\alpha$ is from star formation, we inf...

  8. Image Segmentation By Cluster Analysis Of High Resolution Textured SPOT Images

    Science.gov (United States)

    Slimani, M.; Roux, C.; Hillion, A.

    1986-04-01

    Textural analysis is now a commonly used technique in digital image processing. In this paper, we present an application of textural analysis to high resolution SPOT satellite images. The purpose of the methodology is to improve classification results, i.e. image segmentation in remote sensing. Remote sensing techniques, based on high resolution satellite data offer good perspectives for the cartography of littoral environment. Textural information contained in the pan-chromatic channel of ten meters resolution is introduced in order to separate different types of structures. The technique we used is based on statistical pattern recognition models and operates in two steps. A first step, features extraction, is derived by using a stepwise algorithm. Segmentation is then performed by cluster analysis using these extracted. features. The texture features are computed over the immediate neighborhood of the pixel using two methods : the cooccurence matrices method and the grey level difference statistics method. Image segmentation based only on texture features is then performed by pixel classification and finally discussed. In a future paper, we intend to compare the results with aerial data in view of the management of the littoral resources.

  9. Fast and high resolution single-cell BRET imaging.

    Science.gov (United States)

    Goyet, Elise; Bouquier, Nathalie; Ollendorff, Vincent; Perroy, Julie

    2016-01-01

    Resonance Energy Transfer (RET)-based technologies are used to report protein-protein interactions in living cells. Among them, Bioluminescence-initiated RET (BRET) provides excellent sensitivity but the low light intensity intrinsic to the bioluminescent process hampers its use for the localization of protein complexes at the sub-cellular level. Herein we have characterized the methodological conditions required to reliably perform single-cell BRET imaging using an extremely bright luciferase, Nanoluciferase (Nluc). With this, we achieved an unprecedented performance in the field of protein-protein interaction imaging in terms of temporal and spatial resolution, duration of signal stability, signal sensitivity and dynamic range. As proof-of-principle, an Nluc-containing BRET-based sensor of ERK activity enabled the detection of subtle, transient and localized variations in ERK activity in neuronal dendritic spines, induced by the activation of endogenous synaptic NMDA receptors. This development will improve our comprehension of both the spatio-temporal dynamics of protein-protein interactions and the activation patterns of specific signaling pathways. PMID:27302735

  10. Understanding active galactic nuclei using near-infrared high angular resolution polarimetry I : MontAGN - stokes comparison

    CERN Document Server

    Grosset, Lucas; Gratadour, Damien; Goosmann, René; Rouan, Daniel; Clénet, Yann; Pelat, Didier; Lobos, Patricia Andrea Rojas

    2016-01-01

    In this first research note of a series of two, we present a comparison between two Monte Carlo radiative transfer codes: MontAGN and STOKES. Both were developed in order to better understand the observed polarisation of Active Galactic Nuclei (AGN). Our final aim is to use these radiative transfer codes to simulate the polarisation maps of a prototypical type-2 radio-quiet AGN on a wide range of wavelengths, from the infrared band with MontAGN to the X-ray energies with STOKES. Doing so, we aim to analyse in depth the recent SPHERE/IRDIS polarimetric observations conducted on NGC 1068. In order to validate the codes and obtain preliminary results, we set for both codes a common and simple AGN model, and compared their polaro-imaging results.

  11. Atmospheric Corrections Using MODTRAN for TOA and Surface BRDF Characteristics from High Resolution Spectroradiometric/Angular Measurements from a Helicopter Platform

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    High-resolution spectral radiance measurements were taken by a spectral radiometer on board a heli copter over the US Oklahoma Southern Great Plain near the Atmospheric Radiation Measurements (ARM) site during August 1998. The radiometer has a spectral range from 350 nm to 2500 nm at 1 nm resolution. The measurements covered several grass and cropland scene types at multiple solar zenith angles. Detailed atmospheric corrections using the Moderate Resolution Transmittance (MODTRAN) radiation model and in-situ sounding and aerosol measurements have been applied to the helicopter measurements in order to re trieve the surface and top of atmosphere (TOA) Bidirectional Reflectance Distribution Function (BRDF) characteristics. The atmospheric corrections are most significant in the visible wavelengths and in the strong water vapor absorption wavelengths in the near infrared region. Adjusting the BRDF to TOA requires a larger correction in the visible channels since Rayleigh scattering contributes significantly to the TOA reflectance. The opposite corrections to the visible and near infrarred wavelengths can alter the radiance dif ference and ratio that many remote sensing techniques are based on, such as the normalized difference vege tation index (NDVI). The data show that surface BRDFs and spectral albedos are highly sensitive to the veg etation type and solar zenith angle while BRDF at TOA depends more on atmospheric conditions and the vi ewing geometry. Comparison with the Clouds and the Earth's Radiant Energy System (CERES) derived clear sky Angular Distribution Model (ADM) for crop and grass scene type shows a standard deviation of 0.08 in broadband anisotropic function at 25° solar zenith angle and 0.15 at 50° solar zenith angle, respectively.

  12. Gradient Permittivity Meta-Structure model for Wide-field Super-resolution imaging with a sub-45 nm resolution.

    Science.gov (United States)

    Cao, Shun; Wang, Taisheng; Xu, Wenbin; Liu, Hua; Zhang, Hongxin; Hu, Bingliang; Yu, Weixing

    2016-03-21

    A gradient permittivity meta-structure (GPMS) model and its application in super-resolution imaging were proposed and discussed in this work. The proposed GPMS consists of alternate metallic and dielectric films with a gradient permittivity which can support surface plasmons (SPs) standing wave interference patterns with a super resolution. By employing the rigorous numerical FDTD simulation method, the GPMS was carefully simulated to find that the period of the SPs interference pattern is only 84 nm for a 532 nm incident light. Furthermore, the potential application of the GPMS for wide-field super-resolution imaging was also discussed and the simulation results show that an imaging resolution of sub-45 nm can be achieved based on the plasmonic structure illumination microscopic method, which means a 5.3-fold improvement on resolution has been achieved in comparison with conventional epifluorescence microscopy. Moreover, besides the super-resolution imaging application, the proposed GPMS model can also be applied for nanolithography and other areas where super resolution patterns are needed.

  13. Detection and quantification of waterborne microorganisms using an image cytometer based on angular spatial frequency processing

    CERN Document Server

    Pérez, Juan Miguel; Martínez, Pedro; Pruneri, Valerio

    2015-01-01

    We introduce a new image cytometer design for detection of very small particulate and demonstrate its capability in water analysis. The device is a compact microscope composed of off--the--shelf components, such as a light emitting diode (LED) source, a complementary metal--oxide--semiconductor (CMOS) image sensor, and a specific combination of optical lenses that allow, through an appropriate software, Fourier transform processing of the sample volume. Waterborne microorganisms, such as Escherichia coli (E. coli), Legionella pneumophila (L. pneumophila) and Phytoplankton, are detected by interrogating the volume sample either in a fluorescent or label-free mode, i.e. with or without fluorescein isothiocyanate (FITC) molecules attached to the micro-organisms, respectively. We achieve a sensitivity of 50 CFU/ml, which can be further increased to 0.2 CFU/ml by pre-concentrating an initial sample volume of 500 ml with an ad hoc fluidic system. We also prove the capability of the proposed image cytometer of diffe...

  14. A novel super resolution reconstruction of low reoslution images progressively using dct and zonal filter based denoising

    CERN Document Server

    Liyakathunisa,

    2011-01-01

    Due to the factors like processing power limitations and channel capabilities images are often down sampled and transmitted at low bit rates resulting in a low resolution compressed image. High resolution images can be reconstructed from several blurred, noisy and down sampled low resolution images using a computational process know as super resolution reconstruction. Super-resolution is the process of combining multiple aliased low-quality images to produce a high resolution, high-quality image. The problem of recovering a high resolution image progressively from a sequence of low resolution compressed images is considered. In this paper we propose a novel DCT based progressive image display algorithm by stressing on the encoding and decoding process. At the encoder we consider a set of low resolution images which are corrupted by additive white Gaussian noise and motion blur. The low resolution images are compressed using 8 by 8 blocks DCT and noise is filtered using our proposed novel zonal filter. Multifr...

  15. High-Resolution Imaging of Asteroids/Satellites with AO

    Science.gov (United States)

    Merline, William

    2012-02-01

    We propose to make high-resolution observations of asteroids using AO, to measure size, shape, and pole position (spin vectors), and/or to search for satellites. We have demonstrated that AO imaging allows determination of the pole/dimensions in 1 or 2 nights on a single target, rather than the years of observations with lightcurve inversion techniques that only yield poles and axial ratios, not true dimensions. Our new technique (KOALA) combines AO imaging with lightcurve and occultation data for optimum size/shape determinations. We request that LGS be available for faint targets, but using NGS AO, we will measure several large and intermediate asteroids that are favorably placed in spring/summer of 2012 for size/shape/pole. Accurately determining the volume from the often-irregular shape allows us to derive densities to much greater precision in cases where the mass is known, e.g., from the presence of a satellite. We will search several d! ozen asteroids for the presence of satellites, particularly in under-studied populations, particularly NEOs (we have recently achieved the first-ever optical image of an NEO binary [Merline et al. 2008b, IAUC 8977]). Satellites provide a real-life lab for testing collisional models. We will search for satellites around special objects at the request of lightcurve observers, and we will make a search for debris in the vicinity of Pluto, in support of the New Horizons mission. Our shape/size work requires observations over most of a full rotation period (typically several hours).

  16. Arcsecond-Resolution Submillimeter HCN Imaging of the Binary Protostar IRAS 16293-2422

    CERN Document Server

    Takakuwa, S; Bourke, T; Hirano, N; Ho, P T P; Jorgensen, J; Kuan, Y J; Wilner, D; Yeh, S C C

    2007-01-01

    (Abridged) With the SMA we have made high angular-resolution (~1" = 160 AU) observations of the protobinary system IRAS 16293-2422 in the J = 4-3 lines of HCN and HC^15N, and in the continuum at 354.5 GHz. The HCN (4-3) line was also observed using the JCMT to supply missing short spacing information. Submillimeter continuum emission is detected from the individual binary components with a separation of ~5". The HC^15N (4-3) emission has revealed a compact (~500 AU) flattened structure (P.A. = -16 degree) associated with Source A, and shows a velocity gradient along the projected minor axis, which can be interpreted as an infalling gas motion. Our HCN image including the short-spacing information shows an extended (~3000 AU) circumbinary envelope as well as the compact structure associated with Source A. A toy model consisting of a flattened structure with radial infall towards a 1 Msun central star reproduces the HCN/HC^15N position-velocity diagram along the minor axis of the HC^15N emission. In the extende...

  17. Providing Stringent Star Formation Rate Limits of z ˜ 2 QSO Host Galaxies at High Angular Resolution

    Science.gov (United States)

    Vayner, Andrey; Wright, Shelley A.; Do, Tuan; Larkin, James E.; Armus, Lee; Gallagher, S. C.

    2016-04-01

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ˜ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ˜0.″2 (˜1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (zHα = 2.182) and SDSS J0925+0655 (zHα = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M⊙ yr-1 originating from a compact region that is kinematically offset by 290-350 km s-1. For SDSS J0925+0655 we infer a SFR of 29 M⊙ yr-1 distributed over three clumps that are spatially offset by ˜7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M⊙ yr-1 kpc-2. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M⊙ yr-1 kpc-2. These IFS observations indicate that while the central black hole is accreting mass at 10%-40% of the Eddington rate, if star formation is present in the host (1.4-20 kpc) it would have to occur diffusely with significant

  18. Snow Cover Maps from MODIS Images at 250 m Resolution, Part 2: Validation

    OpenAIRE

    Marc Zebisch; Christian Steurer; Armin Costa; Roberto Monsorno; Thomas Schellenberger; Anke Tetzlaff; Martial Duguay; Nico Moelg; Claudia Notarnicola

    2013-01-01

    The performance of a new algorithm for binary snow cover monitoring based on Moderate Resolution Imaging Spectroradiometer (MODIS) satellite images at 250 m resolution is validated using snow cover maps (SCA) based on Landsat 7 ETM+ images and in situ snow depth measurements from ground stations in selected test sites in Central Europe. The advantages of the proposed algorithm are the improved ground resolution of 250 m and the near real-time availability with respect to the 500 m standard Na...

  19. Experimental validation of a high-resolution diffuse optical imaging modality: photomagnetic imaging

    Science.gov (United States)

    Nouizi, Farouk; Luk, Alex; Thayer, Dave; Lin, Yuting; Ha, Seunghoon; Gulsen, Gultekin

    2016-01-01

    We present experimental results that validate our imaging technique termed photomagnetic imaging (PMI). PMI illuminates the medium under investigation with a near-infrared light and measures the induced temperature increase using magnetic resonance imaging. A multiphysics solver combining light and heat propagation is used to model spatiotemporal distribution of temperature increase. Furthermore, a dedicated PMI reconstruction algorithm has been developed to reveal high-resolution optical absorption maps from temperature measurements. Being able to perform measurements at any point within the medium, PMI overcomes the limitations of conventional diffuse optical imaging. We present experimental results obtained on agarose phantoms mimicking biological tissue with inclusions having either different sizes or absorption contrasts, located at various depths. The reconstructed images show that PMI can successfully resolve these inclusions with high resolution and recover their absorption coefficient with high-quantitative accuracy. Even a 1-mm inclusion located 6-mm deep is recovered successfully and its absorption coefficient is underestimated by only 32%. The improved PMI system presented here successfully operates under the maximum skin exposure limits defined by the American National Standards Institute, which opens up the exciting possibility of its future clinical use for diagnostic purposes.

  20. Angular velocity discrimination

    Science.gov (United States)

    Kaiser, Mary K.

    1990-01-01

    Three experiments designed to investigate the ability of naive observers to discriminate rotational velocities of two simultaneously viewed objects are described. Rotations are constrained to occur about the x and y axes, resulting in linear two-dimensional image trajectories. The results indicate that observers can discriminate angular velocities with a competence near that for linear velocities. However, perceived angular rate is influenced by structural aspects of the stimuli.

  1. Learning Based Single Frame Image Super-resolution Using Fast Discrete Curvelet Coefficients

    Directory of Open Access Journals (Sweden)

    Anil A. Patil

    2012-10-01

    Full Text Available High-resolution (HR images play a vital role in all imaging applications as they offer more details. The images captured by the camera system are of degraded quality due to the imaging system and are low-resolution (LR images. Image super-resolution (SR is a process, where HR image is obtained from combining one or multiple LR images of same scene. In this paper, learning based single frame image super-resolution technique is proposed by using Fast Discrete Curvelet Transform (FDCT coefficients. FDCT is an extension to Cartesian wavelets having anisotropic scaling with many directions and positions, which forms tight wedges. Such wedges allow FDCT to capture the smooth curves and fine edges at multiresolution level. The finer scale curvelet coefficients of LR image are learnt locally from a set of high-resolution training images. The super-resolved image is reconstructed by inverse Fast Discrete Curvelet Transform (IFDCT. This technique represents fine edges of reconstructed HR image by extrapolating the FDCT coefficients from the high-resolution training images. Experimentation based results show appropriate improvements in MSE and PSNR.

  2. Single-shot and single-sensor high/super-resolution microwave imaging based on metasurface

    Science.gov (United States)

    Wang, Libo; Li, Lianlin; Li, Yunbo; Zhang, Hao Chi; Cui, Tie Jun

    2016-06-01

    Real-time high-resolution (including super-resolution) imaging with low-cost hardware is a long sought-after goal in various imaging applications. Here, we propose broadband single-shot and single-sensor high-/super-resolution imaging by using a spatio-temporal dispersive metasurface and an imaging reconstruction algorithm. The metasurface with spatio-temporal dispersive property ensures the feasibility of the single-shot and single-sensor imager for super- and high-resolution imaging, since it can convert efficiently the detailed spatial information of the probed object into one-dimensional time- or frequency-dependent signal acquired by a single sensor fixed in the far-field region. The imaging quality can be improved by applying a feature-enhanced reconstruction algorithm in post-processing, and the desired imaging resolution is related to the distance between the object and metasurface. When the object is placed in the vicinity of the metasurface, the super-resolution imaging can be realized. The proposed imaging methodology provides a unique means to perform real-time data acquisition, high-/super-resolution images without employing expensive hardware (e.g. mechanical scanner, antenna array, etc.). We expect that this methodology could make potential breakthroughs in the areas of microwave, terahertz, optical, and even ultrasound imaging.

  3. High resolution mosaic image of capillaries in human retina by adaptive optics

    Institute of Scientific and Technical Information of China (English)

    Ning Ling; Yudong Zhang; Xuejun Rao; Cheng Wang; Yiyun Hu; Wenhan Jiang

    2005-01-01

    Adaptive optics (AO) has been proved as a powerful means for high resolution imaging of human retina.Because of the pixel number of charge-coupled device (CCD) camera, the field of view is limited to 1°.In order to have image of capillaries around vivo human fovea, we use mosaic method to obtain high resolution image in area of 6°× 6°. Detailed structures of capillaries around fovea with resolution of 2.3μm are clearly shown. Comparison shows that this method has a much higher resolution than current clinic retina imaging methods.

  4. PROVIDING STRINGENT STAR FORMATION RATE LIMITS OF z ∼ 2 QSO HOST GALAXIES AT HIGH ANGULAR RESOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Vayner, Andrey; Wright, Shelley A. [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Do, Tuan [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON, M5S 3H4 (Canada); Larkin, James E. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Armus, Lee [Spitzer Science Center, California Institute of Technology, 1200 E. California Boulevard, Pasadena, CA 91125 (United States); Gallagher, S. C. [Department of Physics and Astronomy, The University of Western Ontario, London, ON N6A 3K7 (Canada)

    2016-04-10

    We present integral field spectrograph (IFS) with laser guide star adaptive optics (LGS-AO) observations of z ∼ 2 quasi-stellar objects (QSOs) designed to resolve extended nebular line emission from the host galaxy. Our data was obtained with W. M. Keck and Gemini North Observatories, using OSIRIS and NIFS coupled with the LGS-AO systems, respectively. We have conducted a pilot survey of five QSOs, three observed with NIFS+AO and two observed with OSIRIS+AO at an average redshift of z = 2.2. We demonstrate that the combination of AO and IFSs provides the necessary spatial and spectral resolutions required to separate QSO emission from its host. We present our technique for generating a point-spread function (PSF) from the broad-line region of the QSO and performing PSF subtraction of the QSO emission to detect the host galaxy emission at a separation of ∼0.″2 (∼1.4 kpc). We detect Hα narrow-line emission for two sources, SDSS J1029+6510 (z{sub Hα} = 2.182) and SDSS J0925+0655 (z{sub Hα} = 2.197), that have evidence for both star formation and extended narrow-line emission. Assuming that the majority of narrow-line Hα emission is from star formation, we infer a star formation rate (SFR) for SDSS J1029+6510 of 78.4 M{sub ⊙} yr{sup −1} originating from a compact region that is kinematically offset by 290–350 km s{sup −1}. For SDSS J0925+0655 we infer a SFR of 29 M{sub ⊙} yr{sup −1} distributed over three clumps that are spatially offset by ∼7 kpc. The null detections on three of the QSOs are used to infer surface brightness limits and we find that at 1.4 kpc from the QSO the un-reddened star formation limit is ≲0.3 M{sub ⊙} yr{sup −1} kpc{sup −2}. If we assume typical extinction values for z = 2 type-1 QSOs, the dereddened SFR for our null detections would be ≲0.6 M{sub ⊙} yr{sup −1} kpc{sup −2}. These IFS observations indicate that while the central black hole is accreting mass at 10%–40% of the Eddington rate, if

  5. High Resolution Imaging by Atomic Force Microscopy: Contribution of short-range force to the imaging

    Science.gov (United States)

    Eguchi, Toyoaki; Kotone, Akiyama; Masanori, Ono; Toshio, Sakurai; Yukio, Hasegawa

    2003-03-01

    Recent developments in force detection technique have made us possible to obtain atomically resolved images of the Si(111)-(7x7) surface by AFM. Compared with STM, however, its spatial resolution remains limited. In this presentation, we demonstrate that with careful pretreatment and appropriate experimental parameters, the structure of the rest-atom layer can be imaged using AFM by detecting the short-range force due to the single chemical bonding. The detection of the short-range force is verified by analysis of the frequency-shift versus distance curve (force curve). This unprecedented high resolution is achieved by reducing background forces due to the long-range interactions with small oscillation amplitude of the cantilever and an atomically sharp tip. The high temperature annealing of the cantilever assists in obtaining a bare silicon tip on the cantilever without unwanted tip-blunting, and improving the Q-factor of the cantilever. This study implies that characterization of the AFM tip in nanometer scale, not only on the apex atoms but also its shape near the apex, is important and critical for AFM high resolution imaging.

  6. High Resolution Multispectral Flow Imaging of Cells with Extended Depth of Field Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Proposed is the development the extended depth of field (EDF) or confocal like imaging capabilities of a breakthrough multispectral high resolution imaging flow...

  7. Detecting Changes Between Optical Images of Different Spatial and Spectral Resolutions: a Fusion-Based Approach

    CERN Document Server

    Ferraris, Vinicius; Wei, Qi; Chabert, Marie

    2016-01-01

    Change detection is one of the most challenging issues when analyzing remotely sensed images. Comparing several multi-date images acquired through the same kind of sensor is the most common scenario. Conversely, designing robust, flexible and scalable algorithms for change detection becomes even more challenging when the images have been acquired by two different kinds of sensors. This situation arises in case of emergency under critical constraints. This paper presents, to the best of authors' knowledge, the first strategy to deal with optical images characterized by dissimilar spatial and spectral resolutions. Typical considered scenarios include change detection between panchromatic or multispectral and hyperspectral images. The proposed strategy consists of a 3-step procedure: i) inferring a high spatial and spectral resolution image by fusion of the two observed images characterized one by a low spatial resolution and the other by a low spectral resolution, ii) predicting two images with respectively the...

  8. Complementarity of PALM and SOFI for super-resolution live cell imaging of focal adhesions

    CERN Document Server

    Deschout, Hendrik; Sharipov, Azat; Szlag, Daniel; Feletti, Lely; Vandenberg, Wim; Dedecker, Peter; Hofkens, Johan; Leutenegger, Marcel; Lasser, Theo; Radenovic, Aleksandra

    2016-01-01

    Live cell imaging of focal adhesions requires a sufficiently high temporal resolution, which remains a challenging task for super-resolution microscopy. We have addressed this important issue by combining photo-activated localization microscopy (PALM) with super-resolution optical fluctuation imaging (SOFI). Using simulations and fixed cell focal adhesion images, we investigated the complementarity between PALM and SOFI in terms of spatial and temporal resolution. This PALM-SOFI framework was used to image focal adhesions in living cells, while obtaining a temporal resolution below 10 s. We visualized the dynamics of focal adhesions, and revealed local mean velocities around 190 nm per minute. The complementarity of PALM and SOFI was assessed in detail with a methodology that integrates a quantitative resolution and signal-to-noise metric. This PALM and SOFI concept provides an enlarged quantitative imaging framework, allowing unprecedented functional exploration of focal adhesions through the estimation of m...

  9. Signal Amplification Technique (SAT): an approach for improving resolution and reducing image noise in computed tomography

    International Nuclear Information System (INIS)

    Spatial resolution improvements in computed tomography (CT) have been limited by the large and unique error propagation properties of this technique. The desire to provide maximum image resolution has resulted in the use of reconstruction filter functions designed to produce tomographic images with resolution as close as possible to the intrinsic detector resolution. Thus, many CT systems produce images with excessive noise with the system resolution determined by the detector resolution rather than the reconstruction algorithm. CT is a rigorous mathematical technique which applies an increasing amplification to increasing spatial frequencies in the measured data. This mathematical approach to spatial frequency amplification cannot distinguish between signal and noise and therefore both are amplified equally. We report here a method in which tomographic resolution is improved by using very small detectors to selectively amplify the signal and not noise. Thus, this approach is referred to as the signal amplification technique (SAT). SAT can provide dramatic improvements in image resolution without increases in statistical noise or dose because increases in the cutoff frequency of the reconstruction algorithm are not required to improve image resolution. Alternatively, in cases where image counts are low, such as in rapid dynamic or receptor studies, statistical noise can be reduced by lowering the cutoff frequency while still maintaining the best possible image resolution. A possible system design for a positron CT system with SAT is described

  10. Signal Amplification Technique (SAT): an approach for improving resolution and reducing image noise in computed tomography

    Energy Technology Data Exchange (ETDEWEB)

    Phelps, M.E.; Huang, S.C.; Hoffman, E.J.; Plummer, D.; Carson, R.

    1981-01-01

    Spatial resolution improvements in computed tomography (CT) have been limited by the large and unique error propagation properties of this technique. The desire to provide maximum image resolution has resulted in the use of reconstruction filter functions designed to produce tomographic images with resolution as close as possible to the intrinsic detector resolution. Thus, many CT systems produce images with excessive noise with the system resolution determined by the detector resolution rather than the reconstruction algorithm. CT is a rigorous mathematical technique which applies an increasing amplification to increasing spatial frequencies in the measured data. This mathematical approach to spatial frequency amplification cannot distinguish between signal and noise and therefore both are amplified equally. We report here a method in which tomographic resolution is improved by using very small detectors to selectively amplify the signal and not noise. Thus, this approach is referred to as the signal amplification technique (SAT). SAT can provide dramatic improvements in image resolution without increases in statistical noise or dose because increases in the cutoff frequency of the reconstruction algorithm are not required to improve image resolution. Alternatively, in cases where image counts are low, such as in rapid dynamic or receptor studies, statistical noise can be reduced by lowering the cutoff frequency while still maintaining the best possible image resolution. A possible system design for a positron CT system with SAT is described.

  11. 256-MSCT image acquisition with sequential axial scans. Evaluation of image quality and resolution in a phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Klink, T.; Schwartz, B.; Regier, M.; Adam, G. [Universitaetsklinikum Hamburg-Eppendorf (Germany). Klinik und Poliklinik fuer Diagnostische und Interventionelle Radiologie; Nagel, H. [Dr. HD Nagel - Wissenschaft und Technik fuer die Radiologie, Buchholz (Germany); Begemann, P.G. [Roentgeninstitut Duesseldorf (Germany)

    2012-03-15

    Evaluation of image quality and resolution of varying sequential axial scan protocols utilizing two resolution phantoms with a 256-MSCT scanner. Sequential axial scans were performed on a z-axis and an axial-plane resolution phantom with varying acquisition and reconstruction parameters. Two independent observers evaluated the image quality and resolution, and analyzed quantitative image quality parameters and radiation doses. The best image quality and resolution were achieved with an activated z-flying focal spot (zFFS) and overlapping reconstruction. With an activated zFFS, image degradation was significantly minimized in marginal or overlapping zones of the beam, but the maximum effective detector width was reduced to 82 % and 75 %, respectively depending on the field of view. With a deactivated zFFS, the effective detector width was not restricted, but the image quality decreased and the artifacts increased as the collimation increased. For sequential axial CT data acquisition with multi-planar image reformation, the zFFS technique is crucial to achieve the best image quality and resolution. Major advantages are minimized image degradation and increased spatial resolution along the z-axis, but the zFFS reduces the maximum effective detector width. (orig.)

  12. Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs

    CERN Document Server

    Boyajian, Tabetha; Feiden, Gregory A; Huber, Daniel; Basu, Sarbani; Demarque, Pierre; Fischer, Debra A; Schaefer, Gail; Mann, Andrew W; White, Timothy R; Maestro, Vicente; Brewer, John; Lamell, C Brooke; Spada, Federico; López-Morales, Mercedes; Ireland, Michael; Farrington, Chris; van Belle, Gerard T; Kane, Stephen R; Jones, Jeremy; Brummelaar, Theo A ten; Ciardi, David R; McAlister, Harold A; Ridgway, Stephen; Goldfinger, P J; Turner, Nils H; Sturmann, Laszlo

    2014-01-01

    We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be theta_LD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (T_eff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R_* = 0.805 +/- 0.016, 1.203 +/- 0.061 R_sun), mean stellar densities (rho_* = 1.62 +/- 0.11, 0.58 +/- 0.14 rho_sun), planetary radii (R_p = 1.216 +/- 0.024, 1.451 +/- 0.074 R_Jup), and mean ...

  13. A theoretical analysis of the super-resolution capacity of imagers using speckle illuminations

    CERN Document Server

    Idier, Jérôme; Liu, Penghuan; Allain, Marc; Bourguignon, Sébastien; Sentenac, Anne

    2015-01-01

    Speckle based imaging consists in forming a super-resolved reconstruction of an unknown object from low-resolution images obtained under random inhomogeneous illuminations (speckles). However, the origin of this super-resolution is unclear. In this work, we demonstrate that, under physically realistic conditions, the correlation of the data have a super-resolution power corresponding to the squaring of the imager point spread function. This theoretical result is important for many practical imaging systems such as acoustic and electromagnetic tomographies, fluorescence and photoacoustic microscopies or synthetic aperture radar imaging.

  14. Multi-Sensor Fusion of Infrared and Electro-Optic Signals for High Resolution Night Images

    Directory of Open Access Journals (Sweden)

    Victor Lawrence

    2012-07-01

    Full Text Available Electro-optic (EO image sensors exhibit the properties of high resolution and low noise level at daytime, but they do not work in dark environments. Infrared (IR image sensors exhibit poor resolution and cannot separate objects with similar temperature. Therefore, we propose a novel framework of IR image enhancement based on the information (e.g., edge from EO images, which improves the resolution of IR images and helps us distinguish objects at night. Our framework superimposing/blending the edges of the EO image onto the corresponding transformed IR image improves their resolution. In this framework, we adopt the theoretical point spread function (PSF proposed by Hardie et al. for the IR image, which has the modulation transfer function (MTF of a uniform detector array and the incoherent optical transfer function (OTF of diffraction-limited optics. In addition, we design an inverse filter for the proposed PSF and use it for the IR image transformation. The framework requires four main steps: (1 inverse filter-based IR image transformation; (2 EO image edge detection; (3 registration; and (4 blending/superimposing of the obtained image pair. Simulation results show both blended and superimposed IR images, and demonstrate that blended IR images have better quality over the superimposed images. Additionally, based on the same steps, simulation result shows a blended IR image of better quality when only the original IR image is available.

  15. Super-resolution image transfer by a vortex-like metamaterial

    CERN Document Server

    Dong, Hui Yuan; Fung, Kin Hung; Cui, Tie Jun

    2013-01-01

    We propose a vortex-like metamaterial device that is capable of transferring image along a spiral route without losing subwavelength information of the image. The super-resolution image can be guided and magnified at the same time with one single design. Our design may provide insights in manipulating super-resolution image in a more flexible manner. Examples are given and illustrated with numerical simulations.

  16. Far-field fluorescence microscopy beyond the diffraction limit: Fluorescence imaging with ultrahigh resolution

    OpenAIRE

    Rice, James H.

    2007-01-01

    Fluorescence microscopy is an important and extensively utilised tool for imaging biological systems. However, the image resolution that can be obtained has a limit as defined through the laws of diffraction. Demand for improved resolution has stimulated research into developing methods to image beyond the diffraction limit based on far-field fluorescence microscopy techniques. Rapid progress is being made in this area of science with methods emerging that enable fluorescence imaging in the f...

  17. A novel super resolution scheme to acquire and process satellite images

    Science.gov (United States)

    Yin, Dong-yu; Su, Xiao-feng; Lin, Jian-chun; Wang, Gan-quan; Kuang, Ding-bo

    2013-09-01

    Geosynchronous satellite has obvious limitations for the weight and the scale of payloads, and large aperture optical system is not permitted. The optical diffraction limit of small aperture optical system has an adverse impact on the resolution of the acquired images. Therefore, how to get high resolution images using super-resolution technique with the acquired low resolution images becomes a popular problem investigated by researchers. Here, we present a novel scheme to acquire low resolution images and process them to achieve a high resolution image. Firstly, to acquire low resolution images, we adopt a special arrangement pattern of four CCD staggered arrays on the focal plane in the remote sensing satellite framework .These four CCD linear arrays are parallelized with a 0.25√2 pixel shift along the CCD direction and a 1.25 pixel shift along the scanning direction. The rotation angle between the two directions is 45 degree. The tilting sampling mode and the special arrangement pattern allow the sensor to acquire images with a smaller sampling interval which can give the resolution a greater enhancement. Secondly, to reconstruct a high resolution image of pretty good quality with a magnification factor 4, we propose a novel algorithm based on the iterative-interpolation super resolution algorithm (IISR) and the new edge-directed interpolation algorithm (NEDI). The new algorithm makes a critical improvement to NEDI and introduces it into the multi-frame interpolation in IISR. The algorithm can preserve the edges well and requires a relatively small number of low-resolution images to achieve better reconstruction accuracy .In the last part of the paper, we carry out a simulation experiment, and use MSE as the quality measure. The results demonstrate that our new scheme substantially improves the image resolution with both better quantitative quality and visual quality compared with some previous normal methods.

  18. High resolution Doppler imager on the Upper Atmosphere Research Satellite

    Energy Technology Data Exchange (ETDEWEB)

    Skinner, W.R.; Hays, P.B.; Grassl, H.J.; Gell, D.A.; Burrage, M.D.; Marshall, A.R.; Ortland, D.A. [Univ. of Michigan, Ann Arbor, MI (United States)

    1994-12-31

    The High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite has been providing measurements of the wind field in the stratosphere, mesosphere and lower thermosphere since November 1991. Examination of various calibration data indicates the instrument has remained remarkably stable since launch. The instrument has a thermal drift of about 30 m/s/{degree}C (slightly dependent on wavelength) and a long-term temporal drift that has amounted to about 80 m/s since launch. These effects are removed in the data processing leaving an uncertainty in the instrument stability of {minus}2 nVs. The temperature control of the instrument has improved significantly since launch as a new method was implemented. The initial temperature control held the instrument temperature at about {+-}1{degree}C. The improved method, which holds constant the temperature of the optical bench instead of the radiator, keeps the instrument temperature at about 0.2{degree}C. The calibrations indicate very little change in the sensitivity of the instrument. The detector response has shown no degradation and the optics have not changed their transmittance.

  19. Preparation of cell membranes for high resolution imaging by AFM

    International Nuclear Information System (INIS)

    Studies of cell membrane structure by atomic force microscopy (AFM) have been limited because of the softness of cell membranes. Here, we utilize a new technique of sample preparation to lay red blood cell membranes on the top of a mica surface to obtain high resolution images by in-situ AFM on both sides of cell membranes. Our results indicate that the location of oligosaccharides and proteins in red blood cell membranes might be different from the current membrane model. The inner membrane leaflet is covered by dense proteins with fewer free lipids than expected. In contrast, the outer membrane leaflet is quite smooth; oligosaccharides and peptides supposed to protrude out of the outer membrane leaflet surface might be actually hidden in the middle of hydrophilic lipid heads; transmembrane proteins might form domains in the membranes revealed by PNGase F and trypsin digestion. Our result could be significant to interpret some functions about red blood cell membranes and guide to heal the blood diseases related to cell membranes.

  20. Atomic Resolution Imaging and Quantification of Chemical Functionality of Surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, Udo [Yale University

    2014-12-10

    The work carried out from 2006-2014 under DoE support was targeted at developing new approaches to the atomic-scale characterization of surfaces that include species-selective imaging and an ability to quantify chemical surface interactions with site-specific accuracy. The newly established methods were subsequently applied to gain insight into the local chemical interactions that govern the catalytic properties of model catalysts of interest to DoE. The foundation of our work was the development of three-dimensional atomic force microscopy (3D-AFM), a new measurement mode that allows the mapping of the complete surface force and energy fields with picometer resolution in space (x, y, and z) and piconewton/millielectron volts in force/energy. From this experimental platform, we further expanded by adding the simultaneous recording of tunneling current (3D-AFM/STM) using chemically well-defined tips. Through comparison with simulations, we were able to achieve precise quantification and assignment of local chemical interactions to exact positions within the lattice. During the course of the project, the novel techniques were applied to surface-oxidized copper, titanium dioxide, and silicon oxide. On these materials, defect-induced changes to the chemical surface reactivity and electronic charge density were characterized with site-specific accuracy.

  1. Improving resolution and depth of astronomical observations via modern mathematical methods for image analysis

    CERN Document Server

    Castellano, Marco; Fontana, Adriano; Merlin, Emiliano; Pilo, Stefano; Falcone, Maurizio

    2015-01-01

    In the past years modern mathematical methods for image analysis have led to a revolution in many fields, from computer vision to scientific imaging. However, some recently developed image processing techniques successfully exploited by other sectors have been rarely, if ever, experimented on astronomical observations. We present here tests of two classes of variational image enhancement techniques: "structure-texture decomposition" and "super-resolution" showing that they are effective in improving the quality of observations. Structure-texture decomposition allows to recover faint sources previously hidden by the background noise, effectively increasing the depth of available observations. Super-resolution yields an higher-resolution and a better sampled image out of a set of low resolution frames, thus mitigating problematics in data analysis arising from the difference in resolution/sampling between different instruments, as in the case of EUCLID VIS and NIR imagers.

  2. Solving the problem of imaging resolution: stochastic multi-scale image fusion

    Science.gov (United States)

    Karsanina, Marina; Mallants, Dirk; Gilyazetdinova, Dina; Gerke, Kiril

    2016-04-01

    Structural features of porous materials define the majority of its physical properties, including water infiltration and redistribution, multi-phase flow (e.g. simultaneous water/air flow, gas exchange between biologically active soil root zone and atmosphere, etc.) and solute transport. To characterize soil and rock microstructure X-ray microtomography is extremely useful. However, as any other imaging technique, this one also has a significant drawback - a trade-off between sample size and resolution. The latter is a significant problem for multi-scale complex structures, especially such as soils and carbonates. Other imaging techniques, for example, SEM/FIB-SEM or X-ray macrotomography can be helpful in obtaining higher resolution or wider field of view. The ultimate goal is to create a single dataset containing information from all scales or to characterize such multi-scale structure. In this contribution we demonstrate a general solution for merging multiscale categorical spatial data into a single dataset using stochastic reconstructions with rescaled correlation functions. The versatility of the method is demonstrated by merging three images representing macro, micro and nanoscale spatial information on porous media structure. Images obtained by X-ray microtomography and scanning electron microscopy were fused into a single image with predefined resolution. The methodology is sufficiently generic for implementation of other stochastic reconstruction techniques, any number of scales, any number of material phases, and any number of images for a given scale. The methodology can be further used to assess effective properties of fused porous media images or to compress voluminous spatial datasets for efficient data storage. Potential practical applications of this method are abundant in soil science, hydrology and petroleum engineering, as well as other geosciences. This work was partially supported by RSF grant 14-17-00658 (X-ray microtomography study of shale

  3. Undetectable Changes in Image Resolution of Luminance-Contrast Gradients Affect Depth Perception.

    Science.gov (United States)

    Tsushima, Yoshiaki; Komine, Kazuteru; Sawahata, Yasuhito; Morita, Toshiya

    2016-01-01

    A great number of studies have suggested a variety of ways to get depth information from two dimensional images such as binocular disparity, shape-from-shading, size gradient/foreshortening, aerial perspective, and so on. Are there any other new factors affecting depth perception? A recent psychophysical study has investigated the correlation between image resolution and depth sensation of Cylinder images (A rectangle contains gradual luminance-contrast changes.). It was reported that higher resolution images facilitate depth perception. However, it is still not clear whether or not the finding generalizes to other kinds of visual stimuli, because there are more appropriate visual stimuli for exploration of depth perception of luminance-contrast changes, such as Gabor patch. Here, we further examined the relationship between image resolution and depth perception by conducting a series of psychophysical experiments with not only Cylinders but also Gabor patches having smoother luminance-contrast gradients. As a result, higher resolution images produced stronger depth sensation with both images. This finding suggests that image resolution affects depth perception of simple luminance-contrast differences (Gabor patch) as well as shape-from-shading (Cylinder). In addition, this phenomenon was found even when the resolution difference was undetectable. This indicates the existence of consciously available and unavailable information in our visual system. These findings further support the view that image resolution is a cue for depth perception that was previously ignored. It partially explains the unparalleled viewing experience of novel high resolution displays.

  4. RCS Computation Technique Based on ISAR Imaging for Large Angular Rotation Problem%基于ISAR成像的目标大角度RCS外推

    Institute of Scientific and Technical Information of China (English)

    闫伟; 杜卫民; 董群锋; 许家栋

    2012-01-01

    传统逆合成孔径雷达(ISAR)转台成像算法对目标进行成像后只能外推小角度区域雷达散射截面(RCS).针对这一问题,建立了大转角转台成像系统,提出了一种基于近场微波成像的RCS外推算法,分析了近场大转角转动带来的越距离单元徙动问题.通过将距离与方位域解耦,并对方位方向进行圆周卷积运算,得到高质量的目标成像,进而可以外推目标360度方位的RCS,并与传统ISAR小角度成像算法进行比对.仿真结果表明,外推算法不仅可以对目标进行成像,诊断目标的强散射点位置,还可以用来做远区RCS大角度外推,并结合成像结果分析目标散射机理.%In this paper, a radar cross section ( RCS) extrapolation method was proposed based on inverse synthetic aperture radar (ISAR) imaging system with large angular rotation. It can solve the problem that the ISAR system can not deal with the small angle rotation problem to acquire the RCS. The range cell migration problem caused by large angle rotation was also considered. The proposed system was accomplished by decoupling the green function to range direction and azimuth direction. In azimuth direction, the convolution method was used to obtain the accurate images rapidly. Then, the images were used for RCS extrapolation over 360 degree. The proposed method is testified by simulation results. The results show that the proposed method can be used to acquire high resolution image which can be used for high quality RCS extrapolation.

  5. Resolution to the quantum-classical dilemma in thermal ghost imaging

    OpenAIRE

    Chen, Lixiang

    2016-01-01

    There has been an intense debate on the quantum versus classical origin of ghost imaging with a thermal light source over the last two decades. A lot of distinguished work has contributed to this topic, both theoretically and experimentally, however, to this day this quantum-classical dilemma still persists. Here we formulate for the first time a density matrix in the photon orbital angular momentum (OAM) Hilbert space to fully characterize the two-arm ghost imaging system with the basic defi...

  6. H.E.S.S. observations of RX J1713.7-3946 with improved angular and spectral resolution; evidence for gamma-ray emission extending beyond the X-ray emitting shell

    CERN Document Server

    Abdalla, H; Abramowski, A; Aharonian, F; Benkhali, F Ait; Akhperjanian, A G; Andersson, T; Angüner, E O; Arrieta, M; Aubert, P; Backes, M; Balzer, A; Barnard, M; Becherini, Y; Tjus, J Becker; Berge, D; Bernhard, S; Bernlöhr, K; Blackwell, R; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Bregeon, J; Brun, F; Brun, P; Bryan, M; Büchele, M; Bulik, T; Capasso, M; Carr, J; Casanova, S; Cerruti, M; Chakraborty, N; Chalme-Calvet, R; Chaves, R C G; Chen, A; Chevalier, J; Chrétien, M; Coffaro, M; Colafrancesco, S; Cologna, G; Condon, B; Conrad, J; Cui, Y; Davids, I D; Decock, J; Degrange, B; Deil, C; Devin, J; deWilt, P; Dirson, L; Djannati-Ataï, A; Domainko, W; Donath, A; Drury, L O'C; Dutson, K; Dyks, J; Edwards, T; Egberts, K; Eger, P; Ernenwein, J -P; Eschbach, S; Farnier, C; Fegan, S; Fern, M V; Fiasson, A; Fontaine, G; Förster, A; Funk, S; Füßling, M; Gabici, S; Gajdus, M; Gallant, Y A; Garrigoux, T; Giavitto, G; Giebels, B; Glicenstein, J F; Gottschall, D; Goyal, A; Grondin, M -H; Hadasch, D; Hahn, J; Haupt, M; Hawkes, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hinton, J A; Hofmann, W; Hoischen, C; Holler, M; Horns, D; Ivascenko, A; Jacholkowska, A; Jamrozy, M; Janiak, M; Jankowsky, D; Jankowsky, F; Jingo, M; Jogler, T; Jouvin, L; Jung-Richardt, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kerszberg, D; Khélifi, B; Kieffer, M; King, J; Klepser, S; Klochkov, D; Kluźniak, W; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Kraus, M; Krüger, P P; Laffon, H; Lamanna, G; Lau, J; Lees, J -P; Lefaucheur, J; Lefranc, V; Lemière, A; Lemoine-Goumard, M; Lenain, J -P; Leser, E; Lohse, T; Lorentz, M; Liu, R; López-Coto, R; Lypova, I; Mar, V; Marcowith, A; Mariaud, C; Marx, R; Maurin, G; Maxted, N; Mayer, M; Meintjes, P J; Meyer, M; Mitchell, A M W; Moderski, R; Mohamed, M; Mohrmann, L; Morå, K; Moulin, E; Murach, T; de Naurois, M; Niederwanger, F; Niemiec, J; Oakes, L; O'Brien, P; Odaka, H; Öttl, S; Ohm, S; Ostrowski, M; Oya, I; Padovani, M; Panter, M; Parsons, R D; Pekeur, N W; Pelletier, G; Perennes, C; Petrucci, P -O; Peyaud, B; Piel, Q; Pita, S; Poon, H; Prokhorov, D; Prokoph, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Romoli, C; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Salek, D; Sanchez, D A; Santangelo, A; Sasaki, M; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwemmer, S; Seglar-Arroyo, L; Settimo, M; Seyffert, A S; Shafi, N; Shilon, I; Simoni, R; Sol, H; Spanier, F; Spengler, G; Spies, F; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stycz, K; Sushch, I; Tavernet, J -P; Tavernier, T; Taylor, A M; Terrier, R; Tibaldo, L; Tiziani, D; Tluczykont, M; Trichard, C; Tuffs, R; Uchiyama, Y; van der Walt, D J; van Eldik, C; van Rensburg, C; van Soelen, B; Vasileiadis, G; Veh, J; Venter, C; Viana, A; Vincent, P; Vink, J; Voisin, F; Völk, H J; Vuillaume, T; Wadiasingh, Z; Wagner, S J; Wagner, P; Wagner, R M; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Yang, R; Zabalza, V; Zaborov, D; Zacharias, M; Zanin, R; Zdziarski, A A; Zech, A; Zefi, F; Ziegler, A; Żywucka, N

    2016-01-01

    Supernova remnants exhibit shock fronts (shells) that can accelerate charged particles up to very high energies. In the past decade, measurements of a handful of shell-type supernova remnants in very-high-energy gamma rays have provided unique insights into the acceleration process. Among those objects, RX$~$J1713.7-3946 (also known as G347.3-0.5) has the largest surface brightness, allowing us in the past to perform the most comprehensive study of morphology and spatially resolved spectra of any such very-high-energy gamma-ray source. Here we present extensive new H.E.S.S. measurements of RX$~$J1713.7-3946, almost doubling the observation time compared to our previous publication. Combined with new improved analysis tools, the previous sensitivity is more than doubled. The H.E.S.S. angular resolution of $0.048^\\circ$ ($0.036^\\circ$ above 2 TeV) is unprecedented in gamma-ray astronomy and probes physical scales of 0.8 (0.6) parsec at the remnant's location. The new H.E.S.S. image of RX$~$J1713.7-3946 allows u...

  7. Tract Orientation and Angular Dispersion Deviation Indicator (TOADDI): A framework for single-subject analysis in diffusion tensor imaging

    CERN Document Server

    Koay, Cheng Guan; Ollinger, John M; İrfanoğlu, M Okan; Pierpaoli, Carlo; Basser, Peter J; Oakes, Terrence R; Riedy, Gerard

    2015-01-01

    The purpose of this work is to develop a framework for single-subject analysis of diffusion tensor imaging (DTI) data. This framework (termed TOADDI) is capable of testing whether an individual tract as represented by the major eigenvector of the diffusion tensor and its corresponding angular dispersion are significantly different from a group of tracts on a voxel-by-voxel basis. This work develops two complementary statistical tests based on the elliptical cone of uncertainty (COU), which is a model of uncertainty or dispersion of the major eigenvector of the diffusion tensor. The orientation deviation test examines whether the major eigenvector from a single subject is within the average elliptical COU formed by a collection of elliptical COUs. The shape deviation test is based on the two-tailed Wilcoxon-Mann-Whitney two-sample test between the normalized shape measures (area and circumference) of the elliptical cones of uncertainty of the single subject against a group of controls. The False Discovery Rate...

  8. Research on the affect of differential-images technique to the resolution of infrared spatial camera

    Science.gov (United States)

    Jin, Guang; An, Yuan; Qi, Yingchun; Hu, Fusheng

    2007-12-01

    The optical system of infrared spatial camera adopts bigger relative aperture and bigger pixel size on focal plane element. These make the system have bulky volume and low resolution. The potential of the optical systems can not be exerted adequately. So, one method for improving resolution of infrared spatial camera based on multi-frame difference-images is introduced in the dissertation. The method uses more than one detectors to acquire several difference images, and then reconstructs a new high-resolution image from these images through the relationship of pixel grey value. The technique of difference-images that uses more than two detectors is researched, and it can improve the resolution 2.5 times in theory. The relationship of pixel grey value between low-resolution difference-images and high-resolution image is found by analyzing the energy of CCD sampling, a general relationship between the enhanced times of the resolution of the detected figure with differential method and the least count of CCD that will be used to detect figure is given. Based on the research of theory, the implementation process of utilizing difference-images technique to improve the resolution of the figure was simulated used Matlab software by taking a personality image as the object, and the software can output the result as an image. The result gotten from the works we have finished proves that the technique is available in high-resolution image reconstruction. The resolution of infrared spatial camera can be improved evidently when holding the size of optical structure or using big size detector by applying for difference image technique. So the technique has a high value in optical remote fields.

  9. Higher resolution satellite remote sensing and the impact on image mapping

    Science.gov (United States)

    Watkins, Allen H.; Thormodsgard, June M.

    Recent advances in spatial, spectral, and temporal resolution of civil land remote sensing satellite data are presenting new opportunities for image mapping applications. The U.S. Geological Survey's experimental satellite image mapping program is evolving toward larger scale image map products with increased information content as a result of improved image processing techniques and increased resolution. Thematic mapper data are being used to produce experimental image maps at 1:100,000 scale that meet established U.S. and European map accuracy standards. Availability of high quality, cloud-free, 30-meter ground resolution multispectral data from the Landsat thematic mapper sensor, along with 10-meter ground resolution panchromatic and 20-meter ground resolution multispectral data from the recently launched French SPOT satellite, present new cartographic and image processing challenges. The need to fully exploit these higher resolution data increases the complexity of processing the images into large-scale image maps. The removal of radiometric artifacts and noise prior to geometric correction can be accomplished by using a variety of image processing filters and transforms. Sensor modeling and image restoration techniques allow maximum retention of spatial and radiometric information. An optimum combination of spectral information and spatial resolution can be obtained by merging different sensor types. These processing techniques are discussed and examples are presented.

  10. Super-resolution deep imaging with hollow Bessel beam STED microscopy

    CERN Document Server

    Yu, Wentao; Dong, Dashan; Yang, Xusan; Xiao, Yunfeng; Gong, Qihuang; Xi, Peng; Shi, Kebin

    2015-01-01

    Stimulated emission depletion (STED) microscopy has become a powerful imaging and localized excitation method beating the diffraction barrier for improved lateral spatial resolution in cellular imaging, lithography, etc. Due to specimen-induced aberrations and scattering distortion, it has been a great challenge for STED to maintain consistent lateral resolution deeply inside the specimens. Here we report on a deep imaging STED microscopy by using Gaussian beam for excitation and hollow Bessel beam for depletion (GB-STED). The proposed scheme shows the improved imaging depth up to ~155{\\mu}m in solid agarose sample, ~115{\\mu}m in PDMS and ~100{\\mu}m in phantom of gray matter in brain tissue with consistent super resolution, while the standard STED microscopy shown a significantly reduced lateral resolution at the same imaging depth. The results indicate the excellent imaging penetration capability of GB-STED, making it a promising tool for deep 3D imaging optical nanoscopy and laser fabrication.

  11. Whole-animal functional and developmental imaging with isotropic spatial resolution.

    Science.gov (United States)

    Chhetri, Raghav K; Amat, Fernando; Wan, Yinan; Höckendorf, Burkhard; Lemon, William C; Keller, Philipp J

    2015-12-01

    Imaging fast cellular dynamics across large specimens requires high resolution in all dimensions, high imaging speeds, good physical coverage and low photo-damage. To meet these requirements, we developed isotropic multiview (IsoView) light-sheet microscopy, which rapidly images large specimens via simultaneous light-sheet illumination and fluorescence detection along four orthogonal directions. Combining these four views by means of high-throughput multiview deconvolution yields images with high resolution in all three dimensions. We demonstrate whole-animal functional imaging of Drosophila larvae at a spatial resolution of 1.1-2.5 μm and temporal resolution of 2 Hz for several hours. We also present spatially isotropic whole-brain functional imaging in Danio rerio larvae and spatially isotropic multicolor imaging of fast cellular dynamics across gastrulating Drosophila embryos. Compared with conventional light-sheet microscopy, IsoView microscopy improves spatial resolution at least sevenfold and decreases resolution anisotropy at least threefold. Compared with existing high-resolution light-sheet techniques, IsoView microscopy effectively doubles the penetration depth and provides subsecond temporal resolution for specimens 400-fold larger than could previously be imaged.

  12. High resolution Cerenkov light imaging of induced positron distribution in proton therapy

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp; Fujii, Kento; Morishita, Yuki; Okumura, Satoshi; Komori, Masataka [Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine, Aichi 461-8673 (Japan); Toshito, Toshiyuki [Department of Proton Therapy Physics, Nagoya Proton Therapy Center, Nagoya City West Medical Center, Aichi 462-8508 (Japan)

    2014-11-01

    Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy. Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a {sup 22}Na point source for the actual imaging setup. Then the transparent acrylic phantoms (100 × 100 × 100 mm{sup 3}) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera. Results: The Cerenkov light’s spatial resolution for the setup was 0.76 ± 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons. Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The

  13. Resolution of ghost imaging with entangled photons for different types of momentum correlation

    Science.gov (United States)

    Zhong, MaLin; Xu, Ping; Lu, LiangLiang; Zhu, ShiNing

    2016-07-01

    We present an analytical analysis of the spatial resolution of quantum ghost imaging implemented by entangled photons from a general, spontaneously parametric, down-conversion process. We find that the resolution is affected by both the pump beam waist and the nonlinear crystal length. Hence, we determined a method to improve the resolution for a certain imaging setup. It should be noted that the resolution is not uniquely related to the degree of entanglement of the photon pair since the resolution can be optimized for a certain degree of entanglement. For certain types of Einstein-Podolsky-Rosen (EPR) states——namely the momentum-correlated or momentum-positively correlated states——the resolution exhibits a simpler relationship with the pump beam waist and crystal length. Further, a vivid numerical simulation of ghost imaging is presented for different types of EPR states, which supports our analysis. This work discusses applicable references to the applications of quantum ghost imaging.

  14. Radial Basis Function Neural Network Based Super-Resolution Restoration for an Underspled Image

    Institute of Scientific and Technical Information of China (English)

    苏秉华; 金伟其; 牛丽红

    2004-01-01

    To achieve restoration of high frequency information for an underspled and degraded low-resolution image, a nonlinear and real-time processing method-the radial basis function (RBF) neural network based super-resolution method of restoration is proposed. The RBF network configuration and processing method is suitable for a high resolution restoration from an underspled low-resolution image. The soft-competition learning scheme based on the k-means algorithm is used, and can achieve higher mapping approximation accuracy without increase in the network size. Experiments showed that the proposed algorithm can achieve a super-resolution restored image from an underspled and degraded low-resolution image, and requires a shorter training time when compared with the multiplayer perception (MLP) network.

  15. A tilted fiber-optic plate coupled CCD detector for high resolution neutron imaging

    International Nuclear Information System (INIS)

    One of these efforts is that a tilted scintillator geometry and lens coupled CCD detector for neutron imaging system were used to improve spatial resolution in one dimension. The increased spatial resolution in one dimension was applied to fuel cell study. However, a lens coupled CCD detector has lower sensitivity than a fiber-optic plate coupled CCD detector due to light loss. In this research, a tilted detector using fiber-optic plate coupled CCD detector was developed to improve resolution and sensitivity. In addition, a tilted detector can prevent an image sensor from direct radiation damage. Neutron imaging has been used for fuel cell study, lithium ion battery study, and many scientific applications. High quality neutron imaging is demanded for more detailed studies of applications, and spatial resolution should be considered to get high quality neutron imaging. Therefore, there were many efforts to improve spatial resolution

  16. High Resolution Seismic Imaging of the Brawley Seismic Fault Zone

    Science.gov (United States)

    Goldman, M.; Catchings, R. D.; Rymer, M. J.; Lohman, R. B.; McGuire, J. J.; Sickler, R. R.; Criley, C.; Rosa, C.

    2011-12-01

    In March 2010, we acquired a series of high-resolution P-wave seismic reflection and refraction data sets across faults in the Brawley seismic zone (BSZ) within the Salton Sea Geothermal Field (SSGF). Our objectives were to determine the dip, possible structural complexities, and seismic velocities within the BSZ. One dataset was 3.4 km long trending east-west, and consisted of 334 shots recorded by a 2.4 km spread of 40 hz geophones placed every 10 meters. The spread was initially laid out from the first station at the eastern end of the profile to roughly 2/3 into the profile. After about half the shots, the spread was shifted from roughly 1/3 into the profile to the last station at the western end of the profile. P-waves were generated by Betsy-Seisgun 'shots' spaced every 10 meters. Initial analysis of first breaks indicate near-surface velocities of ~500-600 meters/sec, and deeper velocities of around 2000 meters/sec. Preliminary investigation of shot gathers indicate a prominent fault that extends to the ground surface. This fault is on a projection of the Kalin fault from about 40 m to the south, and broke the surface down to the west with an approximately north-south strike during a local swarm of earthquakes in 2005 and also slipped at the surface in association with the 2010 El Mayor-Cucapah earthquake in Baja California. The dataset is part of the combined Obsidian Creep data set, and provides the most detailed, publicly available subsurface images of fault structures in the BSZ and SSGF.

  17. Progress in BazookaSPECT: High-Resolution, Dynamic Scintigraphy with Large-Area Imagers

    OpenAIRE

    Miller, Brian W.; Barber, H. Bradford; Barrett, Harrison H.; Liu, Zhonglin; Nagarkar, Vivek V.; Furenlid, Lars R.

    2012-01-01

    We present recent progress in BazookaSPECT, a high-resolution, photon-counting gamma-ray detector. It is a new class of scintillation detector that combines columnar scintillators, image intensifiers, and CCD (charge-coupled device) or CMOS (complementary metal-oxide semiconductors) sensors for high-resolution imaging. A key feature of the BazookaSPECT paradigm is the capability to easily design custom detectors in terms of the desired intrinsic detector resolution and event detection rate. T...

  18. End-to-End Image Super-Resolution via Deep and Shallow Convolutional Networks

    OpenAIRE

    Wang, Yifan; Wang, Lijun; Wang, Hongyu; Li, Peihua

    2016-01-01

    One impressive advantage of convolutional neural networks (CNNs) is their ability to automatically learn feature representation from raw pixels, eliminating the need for hand-designed procedures. However, recent methods for single image super-resolution (SR) fail to maintain this advantage. They utilize CNNs in two decoupled steps, i.e., first upsampling the low resolution (LR) image to the high resolution (HR) size with hand-designed techniques (e.g., bicubic interpolation), and then applyin...

  19. One-dimensional Fibonacci grating for far-field super-resolution imaging.

    Science.gov (United States)

    Wu, Kedi; Wang, Guo Ping

    2013-06-15

    One-dimensional Fibonacci gratings are used to transform evanescent waves into propagating waves for far-field super-resolution imaging. By detecting far-field intensity distributions of light through objects in front of the Fibonacci grating in free space, we can observe the objects with nearly λ/9 spatial resolution. Analytical results are verified by numerical simulations. We also discuss the effect of sampling error on imaging resolution of the system. PMID:23938967

  20. High-resolution two-dimensional image upconversion of incoherent light

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2010-01-01

    We consider a technique for high-resolution image upconversion of thermal light. Experimentally, we demonstrate cw upconversion with a resolution of more than 200 × 1000 pixels of thermally illuminated objects. This is the first demonstration (to our knowledge) of high-resolution cw image...... upconversion. The upconversion method promises an alternative route to high-quantum-efficiency all-optical imaging in the mid-IR wavelength region and beyond using standard CCD cameras. A particular advantage of CCD cameras compared to state-of-the-art thermal cameras is the possibility to tailor and tune...... the spectral response leading to functional spectral imaging....

  1. Turbulence strength estimation and super-resolution from an arbitrary set of atmospherically degraded images

    Science.gov (United States)

    Zamek, Steve; Yitzhaky, Yitzhak

    2006-08-01

    In remote sensing, atmospheric turbulence and aerosols limit the image quality. For many practical cases turbulence is shown to be dominant, especially for horizontal close-to-earth imaging in hot environments. In a horizontal long-range imaging it is usually impractical to measure path-averaged refractive index structure constant C n2 (which characterizes the turbulence strength) with conventional equipment. In this paper we propose a method for estimation of C n2 based just on the available recorded turbulence-degraded image sequence. The method exploits the turbulence-induced image "dancing". C n2 is extracted from the estimated image shifts variance. Experimental comparison with C n2 measurements using a scintillometer shows reliable estimation results. We also estimate image motion with sub-pixel accuracy for the purpose of obtaining a high-resolution image by applying a simple super-resolution procedure. Results of super-resolution for real imagery are presented.

  2. POCS Based Super-Resolution Image Reconstruction Using an Adaptive Regularization Parameter

    CERN Document Server

    Panda, S S; Jena, G

    2011-01-01

    Crucial information barely visible to the human eye is often embedded in a series of low-resolution images taken of the same scene. Super-resolution enables the extraction of this information by reconstructing a single image, at a high resolution than is present in any of the individual images. This is particularly useful in forensic imaging, where the extraction of minute details in an image can help to solve a crime. Super-resolution image restoration has been one of the most important research areas in recent years which goals to obtain a high resolution (HR) image from several low resolutions (LR) blurred, noisy, under sampled and displaced images. Relation of the HR image and LR images can be modeled by a linear system using a transformation matrix and additive noise. However, a unique solution may not be available because of the singularity of transformation matrix. To overcome this problem, POCS method has been used. However, their performance is not good because the effect of noise energy has been ign...

  3. 3D multicolor super-resolution imaging offers improved accuracy in neuron tracing.

    Directory of Open Access Journals (Sweden)

    Melike Lakadamyali

    Full Text Available The connectivity among neurons holds the key to understanding brain function. Mapping neural connectivity in brain circuits requires imaging techniques with high spatial resolution to facilitate neuron tracing and high molecular specificity to mark different cellular and molecular populations. Here, we tested a three-dimensional (3D, multicolor super-resolution imaging method, stochastic optical reconstruction microscopy (STORM, for tracing neural connectivity using cultured hippocampal neurons obtained from wild-type neonatal rat embryos as a model system. Using a membrane specific labeling approach that improves labeling density compared to cytoplasmic labeling, we imaged neural processes at 44 nm 2D and 116 nm 3D resolution as determined by considering both the localization precision of the fluorescent probes and the Nyquist criterion based on label density. Comparison with confocal images showed that, with the currently achieved resolution, we could distinguish and trace substantially more neuronal processes in the super-resolution images. The accuracy of tracing was further improved by using multicolor super-resolution imaging. The resolution obtained here was largely limited by the label density and not by the localization precision of the fluorescent probes. Therefore, higher image resolution, and thus higher tracing accuracy, can in principle be achieved by further improving the label density.

  4. Angular Scaling In Jets

    Energy Technology Data Exchange (ETDEWEB)

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC

    2012-02-17

    We introduce a jet shape observable defined for an ensemble of jets in terms of two-particle angular correlations and a resolution parameter R. This quantity is infrared and collinear safe and can be interpreted as a scaling exponent for the angular distribution of mass inside the jet. For small R it is close to the value 2 as a consequence of the approximately scale invariant QCD dynamics. For large R it is sensitive to non-perturbative effects. We describe the use of this correlation function for tests of QCD, for studying underlying event and pile-up effects, and for tuning Monte Carlo event generators.

  5. Enhanced Singular Value Decomposition based Fusion for Super Resolution Image Reconstruction

    Directory of Open Access Journals (Sweden)

    K. Joseph Abraham Sundar

    2015-11-01

    Full Text Available The singular value decomposition (SVD plays a very important role in the field of image processing for applications such as feature extraction, image compression, etc. The main objective is to enhance the resolution of the image based on Singular Value Decomposition. The original image and the subsequent sub-pixel shifted image, subjected to image registration is transferred to SVD domain. An enhanced method of choosing the singular values from the SVD domain images to reconstruct a high resolution image using fusion techniques is proposesed. This technique is called as enhanced SVD based fusion. Significant improvement in the performance is observed by applying enhanced SVD method preceding the various interpolation methods which are incorporated. The technique has high advantage and computationally fast which is most needed for satellite imaging, high definition television broadcasting, medical imaging diagnosis, military surveillance, remote sensing etc.

  6. High resolution 2D image upconversion of incoherent light

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    An optimized method for continuous wave 2-dimensional (2-D) upconversion of incoherent or thermal light is demonstrated and quantified. Using standard resolution targets a resolution of 200×1000 pixels is obtained. The suggested method is viewed in scope of modern CCD cameras operating in the nea...

  7. Detecting breast microcalcifications using super-resolution ultrasound imaging: a clinical study

    Science.gov (United States)

    Huang, Lianjie; Labyed, Yassin; Hanson, Kenneth; Sandoval, Daniel; Pohl, Jennifer; Williamson, Michael

    2013-03-01

    Imaging breast microcalcifications is crucial for early detection and diagnosis of breast cancer. It is challenging for current clinical ultrasound to image breast microcalcifications. However, new imaging techniques using data acquired with a synthetic-aperture ultrasound system have the potential to significantly improve ultrasound imaging. We recently developed a super-resolution ultrasound imaging method termed the phase-coherent multiple-signal classification (PC-MUSIC). This signal subspace method accounts for the phase response of transducer elements to improve image resolution. In this paper, we investigate the clinical feasibility of our super-resolution ultrasound imaging method for detecting breast microcalcifications. We use our custom-built, real-time synthetic-aperture ultrasound system to acquire breast ultrasound data for 40 patients whose mammograms show the presence of breast microcalcifications. We apply our super-resolution ultrasound imaging method to the patient data, and produce clear images of breast calcifications. Our super-resolution ultrasound PC-MUSIC imaging with synthetic-aperture ultrasound data can provide a new imaging modality for detecting breast microcalcifications in clinic without using ionizing radiation.

  8. A Bayesian Super-Resolution Approach to Demosaicing of Blurred Images

    OpenAIRE

    Molina Rafael; Katsaggelos Aggelos K; Vega Miguel

    2006-01-01

    Most of the available digital color cameras use a single image sensor with a color filter array (CFA) in acquiring an image. In order to produce a visible color image, a demosaicing process must be applied, which produces undesirable artifacts. An additional problem appears when the observed color image is also blurred. This paper addresses the problem of deconvolving color images observed with a single coupled charged device (CCD) from the super-resolution point of view. Utilizing the Bayes...

  9. Spatial and frequency-based super-resolution of ultrasound images

    OpenAIRE

    Wu, Mon-Ju; Karls, Joseph; Duenwald-Kuehl, Sarah; Vanderby, Ray; Sethares, William

    2014-01-01

    Modern ultrasound systems can output video images containing more spatial and temporal information than still images. Super-resolution techniques can exploit additional information but face two challenges: image registration and complex motion. In addition, information from multiple available frequencies is unexploited. Herein, we utilised these information sources to create better ultrasound images and videos, extending existing technologies for image capture. Spatial and frequency-based sup...

  10. High resolution crustal image of South California Continental Borderland: Reverse time imaging including multiples

    Science.gov (United States)

    Bian, A.; Gantela, C.

    2014-12-01

    Strong multiples were observed in marine seismic data of Los Angeles Regional Seismic Experiment (LARSE).It is crucial to eliminate these multiples in conventional ray-based or one-way wave-equation based depth image methods. As long as multiples contain information of target zone along travelling path, it's possible to use them as signal, to improve the illumination coverage thus enhance the image quality of structural boundaries. Reverse time migration including multiples is a two-way wave-equation based prestack depth image method that uses both primaries and multiples to map structural boundaries. Several factors, including source wavelet, velocity model, back ground noise, data acquisition geometry and preprocessing workflow may influence the quality of image. The source wavelet is estimated from direct arrival of marine seismic data. Migration velocity model is derived from integrated model building workflow, and the sharp velocity interfaces near sea bottom needs to be preserved in order to generate multiples in the forward and backward propagation steps. The strong amplitude, low frequency marine back ground noise needs to be removed before the final imaging process. High resolution reverse time image sections of LARSE Lines 1 and Line 2 show five interfaces: depth of sea-bottom, base of sedimentary basins, top of Catalina Schist, a deep layer and a possible pluton boundary. Catalina Schist shows highs in the San Clemente ridge, Emery Knoll, Catalina Ridge, under Catalina Basin on both the lines, and a minor high under Avalon Knoll. The high of anticlinal fold in Line 1 is under the north edge of Emery Knoll and under the San Clemente fault zone. An area devoid of any reflection features are interpreted as sides of an igneous plume.

  11. High illumination resolution test of low-light-level image intensifier

    Science.gov (United States)

    Bai, Xiaofeng; Yin, Lei; Zhu, Yufeng; He, Yingping; Miao, Zhuang; Hu, Wen; Hou, Zhipeng; Shi, Hongli

    2013-08-01

    High illumination resolution, which directly determines the applied characteristic of night vision system in flashlight or high light level condition, is an important performance parameter for evaluating the characteristic of low light level image intensifier used in high light level condition. In this article, according to the limited resolution test technique, the test principle, test condition and test method to high illumination resolution are described in detail associated with operation mode and protective way of low light level image intensifier. Test system for measuring the high illumination resolution has been founded based on the limited resolution test system. The value of high illumination for measuring the high illumination resolution has been calculated in theory and measured by illuminometer. High illumination resolution of low light level image intensifiers have been measured in test system, results show that high illumination resolution test system is satisfied the need for measuring high illumination resolution of low light level image intensifier, and test system output light illumination must be greater than 1×103 lux. Light of high illumination, which can be correctly measured by illuminometer, is transferred legitimately. That is worthwhile to evaluate the operational characteristic of low light level image intensifier.

  12. WAHRSIS: A Low-cost, High-resolution Whole Sky Imager With Near-Infrared Capabilities

    CERN Document Server

    Dev, Soumyabrata; Lee, Yee Hui; Winkler, Stefan

    2016-01-01

    Cloud imaging using ground-based whole sky imagers is essential for a fine-grained understanding of the effects of cloud formations, which can be useful in many applications. Some such imagers are available commercially, but their cost is relatively high, and their flexibility is limited. Therefore, we built a new daytime Whole Sky Imager (WSI) called Wide Angle High-Resolution Sky Imaging System. The strengths of our new design are its simplicity, low manufacturing cost and high resolution. Our imager captures the entire hemisphere in a single high-resolution picture via a digital camera using a fish-eye lens. The camera was modified to capture light across the visible as well as the near-infrared spectral ranges. This paper describes the design of the device as well as the geometric and radiometric calibration of the imaging system.

  13. Atomic-resolution incoherent high-angle annular dark field STEM images of Si(011)

    Science.gov (United States)

    Watanabe, K.; Yamazaki, T.; Kikuchi, Y.; Kotaka, Y.; Kawasaki, M.; Hashimoto, I.; Shiojiri, M.

    2001-02-01

    Characteristic atomic-resolution incoherent high-angle annular dark field (HAADF) scanning transmission electron microscope (STEM) images of [011]-orientated Si have been experimentally obtained by a through-focal series. Artificial bright spots appear at positions where no atomic columns exist along the electron beam, in some experimental images. Image simulation, based on the Bloch wave description by the Bethe method, reproduces the through-focal experimental images. It is shown that atomic-resolution HAADF STEM images, which are greatly influenced by the Bloch wave field depending on the incident electron beam probe, cannot always be interpreted intuitively as the projected atomic images. It is also found that the atomic-resolution HAADF STEM images can be simply explained using the relations to the probe functions without the need for complex dynamical simulations.

  14. AN EFFICIENT SUPER RESOLUTION TECHNIQUE FOR LOSS LESS COMPRESSED BAYER COLOUR FILTER ARRAY IMAGES

    Directory of Open Access Journals (Sweden)

    K.Chiranjeevi,

    2011-05-01

    Full Text Available In digital cameras, Bayer color filter array(CFA images are captured and demosaicing is carried out before compression. Recently, it was found that compression-first schemes outperform the conventionaldemosaicing-first schemes in terms of output image quality. An efficient prediction-based lossless compression and super-resolution schemes are proposed in this paper. Compressed image is coded withrice code. The proposed compression and super resolution schemes can achieve a better compression and high image quality than conventional lossless CFA image coding schemes.

  15. Super-Resolution Imaging on Microfluidic Super-Resolution Near-Field Structure

    Institute of Scientific and Technical Information of China (English)

    WANG Pei; TANG Lin; ZHANG Dou-Guo; LU Yong-Hua; JIAO Xiao-Jin; XIE Jian-Ping; MING Hai

    2005-01-01

    @@ We present a new concept of the microfluidic super-resolution near-field structure (MSRENS) based on a microfluidic structure and a super-resolution near-field structure. The near-field distance control, "nano-probe"and scanning can be realized simultaneously using the MSRENS, which is similar to a near-field scanning optical microscope. The design and simulation results are presented. Numerical simulation has demonstrated that the MSRENS with spatial resolution beyond the diffraction limit could be applicable in chemistry, biologics, and many other fields.

  16. Noise Removal with Maintained Spatial Resolution in Raman Images of Cells Exposed to Submicron Polystyrene Particles

    Directory of Open Access Journals (Sweden)

    Linnea Ahlinder

    2016-04-01

    Full Text Available The biodistribution of 300 nm polystyrene particles in A549 lung epithelial cells has been studied with confocal Raman spectroscopy. This is a label-free method in which particles and cells can be imaged without using dyes or fluorescent labels. The main drawback with Raman imaging is the comparatively low spatial resolution, which is aggravated in heterogeneous systems such as biological samples, which in addition often require long measurement times because of their weak Raman signal. Long measurement times may however induce laser-induced damage. In this study we use a super-resolution algorithm with Tikhonov regularization, intended to improve the image quality without demanding an increased number of collected pixels. Images of cells exposed to polystyrene particles have been acquired with two different step lengths, i.e., the distance between pixels, and compared to each other and to corresponding images treated with the super-resolution algorithm. It is shown that the resolution after application of super-resolution algorithms is not significantly improved compared to the theoretical limit for optical microscopy. However, to reduce noise and artefacts in the hyperspectral Raman images while maintaining the spatial resolution, we show that it is advantageous to use short mapping step lengths and super-resolution algorithms with appropriate regularization. The proposed methodology should be generally applicable for Raman imaging of biological samples and other photo-sensitive samples.

  17. Facial identification in very low-resolution images simulating prosthetic vision

    Science.gov (United States)

    Chang, M. H.; Kim, H. S.; Shin, J. H.; Park, K. S.

    2012-08-01

    Familiar facial identification is important to blind or visually impaired patients and can be achieved using a retinal prosthesis. Nevertheless, there are limitations in delivering the facial images with a resolution sufficient to distinguish facial features, such as eyes and nose, through multichannel electrode arrays used in current visual prostheses. This study verifies the feasibility of familiar facial identification under low-resolution prosthetic vision and proposes an edge-enhancement method to deliver more visual information that is of higher quality. We first generated a contrast-enhanced image and an edge image by applying the Sobel edge detector and blocked each of them by averaging. Then, we subtracted the blocked edge image from the blocked contrast-enhanced image and produced a pixelized image imitating an array of phosphenes. Before subtraction, every gray value of the edge images was weighted as 50% (mode 2), 75% (mode 3) and 100% (mode 4). In mode 1, the facial image was blocked and pixelized with no further processing. The most successful identification was achieved with mode 3 at every resolution in terms of identification index, which covers both accuracy and correct response time. We also found that the subjects recognized a distinctive face especially more accurately and faster than the other given facial images even under low-resolution prosthetic vision. Every subject could identify familiar faces even in very low-resolution images. And the proposed edge-enhancement method seemed to contribute to intermediate-stage visual prostheses.

  18. Ultra-high resolution of radiocesium distribution detection based on Cherenkov light imaging

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Ogata, Yoshimune [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Kawachi, Naoki; Suzui, Nobuo; Yin, Yong-Gen; Fujimaki, Shu [Radiotracer Imaging Group, Japan Atomic Energy Agency (Japan)

    2015-03-21

    After the nuclear disaster in Fukushima, radiocesium contamination became a serious scientific concern and research of its effects on plants increased. In such plant studies, high resolution images of radiocesium are required without contacting the subjects. Cherenkov light imaging of beta radionuclides has inherently high resolution and is promising for plant research. Since {sup 137}Cs and {sup 134}Cs emit beta particles, Cherenkov light imaging will be useful for the imaging of radiocesium distribution. Consequently, we developed and tested a Cherenkov light imaging system. We used a high sensitivity cooled charge coupled device (CCD) camera (Hamamatsu Photonics, ORCA2-ER) for imaging Cherenkov light from {sup 137}Cs. A bright lens (Xenon, F-number: 0.95, lens diameter: 25 mm) was mounted on the camera and placed in a black box. With a 100-μm {sup 137}Cs point source, we obtained 220-μm spatial resolution in the Cherenkov light image. With a 1-mm diameter, 320-kBq {sup 137}Cs point source, the source was distinguished within 2-s. We successfully obtained Cherenkov light images of a plant whose root was dipped in a {sup 137}Cs solution, radiocesium-containing samples as well as line and character phantom images with our imaging system. Cherenkov light imaging is promising for the high resolution imaging of radiocesium distribution without contacting the subject.

  19. High resolution PET breast imager with improved detection efficiency

    Science.gov (United States)

    Majewski, Stanislaw

    2010-06-08

    A highly efficient PET breast imager for detecting lesions in the entire breast including those located close to the patient's chest wall. The breast imager includes a ring of imaging modules surrounding the imaged breast. Each imaging module includes a slant imaging light guide inserted between a gamma radiation sensor and a photodetector. The slant light guide permits the gamma radiation sensors to be placed in close proximity to the skin of the chest wall thereby extending the sensitive region of the imager to the base of the breast. Several types of photodetectors are proposed for use in the detector modules, with compact silicon photomultipliers as the preferred choice, due to its high compactness. The geometry of the detector heads and the arrangement of the detector ring significantly reduce dead regions thereby improving detection efficiency for lesions located close to the chest wall.

  20. MAP estimation for hyperspectral image resolution enhancement using an auxiliary sensor.

    Science.gov (United States)

    Hardie, Russell C; Eismann, Michael T; Wilson, Gregory L

    2004-09-01

    This paper presents a novel maximum a posteriori estimator for enhancing the spatial resolution of an image using co-registered high spatial-resolution imagery from an auxiliary sensor. Here, we focus on the use of high-resolution panchomatic data to enhance hyperspectral imagery. However, the estimation framework developed allows for any number of spectral bands in the primary and auxiliary image. The proposed technique is suitable for applications where some correlation, either localized or global, exists between the auxiliary image and the image being enhanced. To exploit localized correlations, a spatially varying statistical model, based on vector quantization, is used. Another important aspect of the proposed algorithm is that it allows for the use of an accurate observation model relating the "true" scene with the low-resolutions observations. Experimental results with hyperspectral data derived from the airborne visible-infrared imaging spectrometer are presented to demonstrate the efficacy of the proposed estimator.

  1. High-resolution texture imaging with hard synchrotron radiation in the moving area detector technique

    CERN Document Server

    Wcislak, L; Klein, H; Garbe, U; Schneider, J R

    2003-01-01

    The orientation distribution of crystallites in polycrystalline materials (called texture) is usually measured by polycrystal X-ray diffraction by 'step-scanning' the sample in angular intervals in the order of 1 deg. This technique is not suited to fully exploit the low angular divergence of hard synchrotron radiation in the order of 'milliradian'. Hence, step-scanning was replaced by a continuous 'sweeping' technique using a continuously shifted area detector. In order to avoid overlapping from different reflections (hkl) a Bragg-angle slit was introduced. The 'moving-detector' technique can be applied to obtain images of orientation as well as of location distributions of crystallites in polycrystalline samples. It is suitable for imaging continuous 'orientation density' distribution functions as well as of 'grain-resolved' textures. The excellent features of high-energy synchrotron radiation combined with the moving area detector technique will be illustrated with several examples including very sharp def...

  2. Sub-pixel processing for super-resolution scanning imaging system with fiber bundle coupling

    Institute of Scientific and Technical Information of China (English)

    Bowen An; Bingbin Xue; Shengda Pan; Guilin Chen

    2011-01-01

    A multilayer fiber bundle is used to couple the image in a remote sensing imaging system. The object image passes through all layers of the fiber bundle in micro-scanning mode. The malposition of adjacent layers arranged in a hexagonal pattern is at sub-pixel scale. Therefore, sub-pixel processing can be applied to improve the spatial resolution. The images coupled by the adjacent layer fibers are separated, and subsequently, the intermediate image is obtained by histogram matching based on one of the separated image called base image. Finally, the intermediate and base images are processed in the frequency domain. The malposition of the adjacent layer fiber is converted to the phase difference in Fourier transform. Considering the limited sensitivity of the experimental instruments and human sight, the image is set as a band-limited signal and the interpolation function of image fusion is found. The results indicate that a super-resolution image with ultra-high spatial resolution is obtained.%@@ A multilayer fiber bundle is used to couple the image in a remote sensing imaging system.The object image passes through all layers of the fiber bundle in micro-scanning mode.The malposition of adjacent layers arranged in a hexagonal pattern is at sub-pixel scale.

  3. Image Super-Resolution via Dual-Dictionary Learning And Sparse Representation

    OpenAIRE

    Zhang, Jian; Zhao, Chen; Xiong, Ruiqin; Ma, Siwei; Zhao, Debin

    2012-01-01

    Learning-based image super-resolution aims to reconstruct high-frequency (HF) details from the prior model trained by a set of high- and low-resolution image patches. In this paper, HF to be estimated is considered as a combination of two components: main high-frequency (MHF) and residual high-frequency (RHF), and we propose a novel image super-resolution method via dual-dictionary learning and sparse representation, which consists of the main dictionary learning and the residual dictionary l...

  4. Super-Resolution Imaging by Arrays of High-Index Spheres Embedded in Transparent Matrices

    CERN Document Server

    Allen, Kenneth W; Li, Yangcheng; Limberopoulos, Nicholaos I; Walker, Dennis E; Urbas, Augustine M; Astratov, Vasily N

    2014-01-01

    We fabricated thin-films made from polydimethylsiloxane (PDMS) with embedded high-index (n~1.9-2.2) microspheres for super-resolution imaging applications. To control the position of microspheres, such films can be translated along the surface of the nanoplasmonic structure to be imaged. Microsphere-assisted imaging, through these matrices, provided lateral resolution of ~{\\lambda}/7 in nanoplasmonic dimer arrays with an illuminating wavelength {\\lambda}=405 nm. Such thin films can be used as contact optical components to boost the resolution capability of conventional microscopes.

  5. Combining scanning tunneling microscopy and synchrotron radiation for high-resolution imaging and spectroscopy with chemical, electronic, and magnetic contrast

    International Nuclear Information System (INIS)

    The combination of high-brilliance synchrotron radiation with scanning tunneling microscopy opens the path to high-resolution imaging with chemical, electronic, and magnetic contrast. Here, the design and experimental results of an in-situ synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system are presented. The system is designed to allow monochromatic synchrotron radiation to enter the chamber, illuminating the sample with x-ray radiation, while an insulator-coated tip (metallic tip apex open for tunneling, electron collection) is scanned over the surface. A unique feature of the SXSTM is the STM mount assembly, designed with a two free-flex pivot, providing an angular degree of freedom for the alignment of the tip and sample with respect to the incoming x-ray beam. The system designed successfully demonstrates the ability to resolve atomic-scale corrugations. In addition, experiments with synchrotron x-ray radiation validate the SXSTM system as an accurate analysis technique for the study of local magnetic and chemical properties on sample surfaces. The SXSTM system's capabilities have the potential to broaden and deepen the general understanding of surface phenomena by adding elemental contrast to the high-resolution of STM. -- Highlights: ► Synchrotron enhanced x-ray scanning tunneling microscope (SXSTM) system designed. ► Unique STM mount design allows angular DOF for tip alignment with x-ray beam. ► System demonstrates ability to resolve atomic corrugations on HOPG. ► Studies show chemical sensitivity with STM tip from photocurrent and tunneling. ► Results show system's ability to study local magnetic (XMCD) properties on Fe films.

  6. High-resolution imaging with a real-time synthetic aperture ultrasound system: a phantom study

    Science.gov (United States)

    Huang, Lianjie; Labyed, Yassin; Simonetti, Francesco; Williamson, Michael; Rosenberg, Robert; Heintz, Philip; Sandoval, Daniel

    2011-03-01

    It is difficult for ultrasound to image small targets such as breast microcalcifications. Synthetic aperture ultrasound imaging has recently developed as a promising tool to improve the capabilities of medical ultrasound. We use two different tissueequivalent phantoms to study the imaging capabilities of a real-time synthetic aperture ultrasound system for imaging small targets. The InnerVision ultrasound system DAS009 is an investigational system for real-time synthetic aperture ultrasound imaging. We use the system to image the two phantoms, and compare the images with those obtained from clinical scanners Acuson Sequoia 512 and Siemens S2000. Our results show that synthetic aperture ultrasound imaging produces images with higher resolution and less image artifacts than Acuson Sequoia 512 and Siemens S2000. In addition, we study the effects of sound speed on synthetic aperture ultrasound imaging and demonstrate that an accurate sound speed is very important for imaging small targets.

  7. High-resolution light field reconstruction using a hybrid imaging system.

    Science.gov (United States)

    Wang, Xiang; Li, Lin; Hou, GuangQi

    2016-04-01

    Recently, light field cameras have drawn much attraction for their innovative performance in photographic and scientific applications. However, narrow baselines and constrained spatial resolution of current light field cameras impose restrictions on their usability. Therefore, we design a hybrid imaging system containing a light field camera and a high-resolution digital single lens reflex camera, and these two kinds of cameras share the same optical path with a beam splitter so as to achieve the reconstruction of high-resolution light fields. The high-resolution 4D light fields are reconstructed with a phase-based perspective variation strategy. First, we apply complex steerable pyramid decomposition on the high-resolution image from the digital single lens reflex camera. Then, we perform phase-based perspective-shift processing with the disparity value, which is extracted from the upsampled light field depth map, to create high-resolution synthetic light field images. High-resolution digital refocused images and high-resolution depth maps can be generated in this way. Furthermore, controlling the magnitude of the perspective shift enables us to change the depth of field rendering in the digital refocused images. We show several experimental results to demonstrate the effectiveness of our approach.

  8. A Bayesian Super-Resolution Approach to Demosaicing of Blurred Images

    Directory of Open Access Journals (Sweden)

    Molina Rafael

    2006-01-01

    Full Text Available Most of the available digital color cameras use a single image sensor with a color filter array (CFA in acquiring an image. In order to produce a visible color image, a demosaicing process must be applied, which produces undesirable artifacts. An additional problem appears when the observed color image is also blurred. This paper addresses the problem of deconvolving color images observed with a single coupled charged device (CCD from the super-resolution point of view. Utilizing the Bayesian paradigm, an estimate of the reconstructed image and the model parameters is generated. The proposed method is tested on real images.

  9. Change detection in very high resolution multisensor optical images

    Science.gov (United States)

    Solano Correa, Yady T.; Bovolo, Francesca; Bruzzone, Lorenzo

    2014-10-01

    This work aims at developing an approach to the detection of changes in multisensor multitemporal VHR optical images. The main steps of the proposed method are: i) multisensor data homogenization; and ii) change detection in multisensor multitemporal VHR optical images. The proposed approach takes advantage of: the conversion to physical quantities suggested by Pacifici et. al.1 , the framework for the design of systems for change detection in VHR images presented by Bruzzone and Bovolo2 and the framework for unsupervised change detection presented by Bovolo and Bruzzone3. Multisensor data homogenization is achieved during pre-processing by taking into account differences in both radiometric and geometric dimensions. Whereas change detection was approached by extracting proper features from multisensor images such that they result to be comparable (at a given level of abstraction) even if extracted from images acquired by different sensors. In order to illustrate the results, a data set made up of a QuickBird and a WorldView-2 images - acquired in 2006 and 2010 respectively - over an area located in the Trentino region of Italy were used. However, the proposed approach is thought to be exportable to multitemporal images coming from passive sensors other than the two mentioned above. The experimental results obtained on the QuickBird and WorlView-2 image pair are accurate. Thus opening to further experiments on multitemporal images acquired by other sensors.

  10. Single-Image Super Resolution for Multispectral Remote Sensing Data Using Convolutional Neural Networks

    Science.gov (United States)

    Liebel, L.; Körner, M.

    2016-06-01

    In optical remote sensing, spatial resolution of images is crucial for numerous applications. Space-borne systems are most likely to be affected by a lack of spatial resolution, due to their natural disadvantage of a large distance between the sensor and the sensed object. Thus, methods for single-image super resolution are desirable to exceed the limits of the sensor. Apart from assisting visual inspection of datasets, post-processing operations—e.g., segmentation or feature extraction—can benefit from detailed and distinguishable structures. In this paper, we show that recently introduced state-of-the-art approaches for single-image super resolution of conventional photographs, making use of deep learning techniques, such as convolutional neural networks (CNN), can successfully be applied to remote sensing data. With a huge amount of training data available, end-to-end learning is reasonably easy to apply and can achieve results unattainable using conventional handcrafted algorithms. We trained our CNN on a specifically designed, domain-specific dataset, in order to take into account the special characteristics of multispectral remote sensing data. This dataset consists of publicly available SENTINEL-2 images featuring 13 spectral bands, a ground resolution of up to 10m, and a high radiometric resolution and thus satisfying our requirements in terms of quality and quantity. In experiments, we obtained results superior compared to competing approaches trained on generic image sets, which failed to reasonably scale satellite images with a high radiometric resolution, as well as conventional interpolation methods.

  11. Angular Momentum

    Science.gov (United States)

    Shakur, Asif; Sinatra, Taylor

    2013-01-01

    The gyroscope in a smartphone was employed in a physics laboratory setting to verify the conservation of angular momentum and the nonconservation of rotational kinetic energy. As is well-known, smartphones are ubiquitous on college campuses. These devices have a panoply of built-in sensors. This creates a unique opportunity for a new paradigm in…

  12. Image tiling for a high-resolution helmet-mounted display

    Science.gov (United States)

    Kurtz, Russell M.; Pradhan, Ranjit D.; Aye, Tin M.; Chua, Kang-Bin; Tengara, Indra; Tun, Nay; Win, Tin; Holmstedt, Jason; Schindler, Axel; Hergert, Steffen

    2005-05-01

    Head-mounted or helmet-mounted displays (HMDs) have long proven invaluable for many military applications. Integrated with head position, orientation, and/or eye-tracking sensors, HMDs can be powerful tools for training. For such training applications as flight simulation, HMDs need to be lightweight and compact with good center-of-gravity characteristics, and must display realistic full-color imagery with eye-limited resolution and large field-of-view (FOV) so that the pilot sees a truly realistic out-the-window scene. Under bright illumination, the resolution of the eye is ~300 μr (1 arc-min), setting the minimum HMD resolution. There are several methods of achieving this resolution, including increasing the number of individual pixels on a CRT or LCD display, thereby increasing the size, weight, and complexity of the HMD; dithering the image to provide an apparent resolution increase at the cost of reduced frame rate; and tiling normal resolution subimages into a single, larger high-resolution image. Physical Optics Corporation (POC) is developing a 5120 × 4096 pixel HMD covering 1500 × 1200 mr with resolution of 300 μr by tiling 20 subimages, each of which has a resolution of 1024 × 1024 pixels, in a 5 × 4 array. We present theory and results of our preliminary development of this HMD, resulting in a 4k × 1k image tiled from 16 subimages, each with resolution 512 × 512, in an 8 × 2 array.

  13. A fast and automatic mosaic method for high-resolution satellite images

    Science.gov (United States)

    Chen, Hongshun; He, Hui; Xiao, Hongyu; Huang, Jing

    2015-12-01

    We proposed a fast and fully automatic mosaic method for high-resolution satellite images. First, the overlapped rectangle is computed according to geographical locations of the reference and mosaic images and feature points on both the reference and mosaic images are extracted by a scale-invariant feature transform (SIFT) algorithm only from the overlapped region. Then, the RANSAC method is used to match feature points of both images. Finally, the two images are fused into a seamlessly panoramic image by the simple linear weighted fusion method or other method. The proposed method is implemented in C++ language based on OpenCV and GDAL, and tested by Worldview-2 multispectral images with a spatial resolution of 2 meters. Results show that the proposed method can detect feature points efficiently and mosaic images automatically.

  14. A Statistical Definition of Image Resolution Based on the Correlation of Pixels

    CERN Document Server

    Zhou, Jian-Feng

    2015-01-01

    Resolution, usually defined by the Rayleigh criterion or the Full Width at Half Maximum of a Point Spread Function, is a basic property of an image. Here, we present a new statistical definition of image resolution based on the cross-correlation properties of the pixels in an image. It is shown that the new definition of image resolution depends not only on the PSF of an imaging device, but also on the signal-to-noise ratio of the data and on the structures of an object. In an image, the resolution does not have to be uniform. Our new definition is also suitable for the interpretation of the result of a deconvolution. We illustrate this, in this paper, with a Wiener deconvolution. It is found that weak structures can be extracted from low signal-to-noise ratio data, but with low resolution; a high-resolution image was obtained from high signal-to-noise ratio data after a Wiener deconvolution. The new definition can also be used to compare various deconvolution algorithms on their processing effects, such as r...

  15. High time-resolution imaging with the MAMA detector systems

    Science.gov (United States)

    Morgan, Jeffrey S.; Timothy, J. Gethyn; Smith, Andrew M.; Hill, Bob; Kasle, David B.

    1990-01-01

    Current uses of the MAMA detector which utilize the photon time-tagging capabilities of these detectors are reported. These applications currently include image stabilization by means of post-processing corrections of platform drift and speckle interferometry. The initial results of a sounding rocket experiment to obtain UV images of NGC 6240 and results from speckle interferometry of Neptune's moon Triton are presented.

  16. Very high resolution satellite data: New challenges in image analysis

    Digital Repository Service at National Institute of Oceanography (India)

    Sathe, P.V.; Muraleedharan, P.M.

    with the exception that a ground-based view covers the entire optical range from 400 to 700 nm while satellite images will be wavelength-specific. Although the images will not surpass details observed by a human eye, they will, in principle, be comparable with aerial...

  17. High Resolution Photoelectron Spectroscopy of Au_2^- and Au_4^- by Photoelectron Imaging

    Science.gov (United States)

    Leon, Iker; Yang, Zheng; Wang, Lai-Sheng

    2013-06-01

    We report high resolution photoelectron spectra of Au_2^- and Au_4^- obtained with a newly-built photoelectron imaging apparatus. Gold anions are produced by laser vaporization and the desired specie is mass selected and focused into the collinear velocity-map imaging (VMI) lens assembly. The design of the imaging lens has allowed us to obtain less than 0.9% energy resolution for high kinetic energy electrons ( > 1eV) while maintaining wavenumber resolution for low kinetic energy electrons. Although gold dimer and tetramer have been studied in the past, we present spectroscopic results under high resolution. For Au_2^-, we report high resolution spectra with an accurate determination of the electron affinity together with a complete vibrational assignment, for both the anion and neutral ground states, while for Au_4^-, we are able to resolve a low frequency mode and obtain accurately the adiabatic detachment energy.

  18. Multi-pulse pumping for far-field super-resolution imaging

    Science.gov (United States)

    Requena, Sebastian; Raut, Sangram; Doan, Hung; Kimball, Joe; Fudala, Rafal; Borejdo, Julian; Gryczynski, Ignacy; Strzhemechny, Yuri; Gryczynski, Zygmunt

    2016-02-01

    Recently, far-field optical imaging with a resolution significantly beyond diffraction limit has attracted tremendous attention allowing for high resolution imaging in living objects. Various methods have been proposed that are divided in to two basic approaches; deterministic super-resolution like STED or RESOLFT and stochastic super-resolution like PALM or STORM. We propose to achieve super-resolution in far-field fluorescence imaging by the use of controllable (on-demand) bursts of pulses that can change the fluorescence signal of long-lived component over one order of magnitude. We demonstrate that two beads, one labeled with a long-lived dye and another with a short-lived dye, separated by a distance lower than 100 nm can be easily resolved in a single experiment. The proposed method can be used to separate two biological structures in a cell by targeting them with two antibodies labeled with long-lived and short-lived fluorophores.

  19. Spectroscopic super-resolution fluorescence cell imaging using ultra-small Ge quantum dots

    CERN Document Server

    Song, Mingying; Ersoy, Osman; Zhou, Yun; Yang, Yongxin; Zhang, Yuanpeng; Little, William R; Wheeler, Ann P; Sapelkin, Andrei V

    2015-01-01

    In single molecule localisation super-resolution microscopy the need for repeated image capture limits the imaging speed, while the size of fluorescence probes limits the possible theoretical localisation resolution. Here, we demonstrated a spectral imaging based super-resolution approach by separating the overlapping diffraction spots into several detectors during a single scanning period and taking advantage of the size-dependent emission wavelength in nanoparticles. This approach has been tested using off-the-shelf quantum dots (Qdot) and in-house novel ultra-small (~3 nm) Ge QDs. Furthermore, we developed a method-specific Gaussian fitting and maximum likelihood estimation based on a Matlab algorithm for fast QDs localisation. We demonstrate that this methodology results in ~ 40 nm localisation resolution using commercial QDs and ~12 nm localisation resolution using Ge QDs. Using a standard scanning confocal microscope we achieved data acquisition rate of 1.6 seconds/frame. However, we show that this appr...

  20. High-resolution adaptive imaging of a single atom

    Science.gov (United States)

    Wong-Campos, J. D.; Johnson, K. G.; Neyenhuis, B.; Mizrahi, J.; Monroe, C.

    2016-09-01

    Optical imaging systems are used extensively in the life and physical sciences because of their ability to non-invasively capture details on the microscopic and nanoscopic scales. Such systems are often limited by source or detector noise, image distortions and human operator misjudgement. Here, we report a general, quantitative method to analyse and correct these errors. We use this method to identify and correct optical aberrations in an imaging system for single atoms and realize an atomic position sensitivity of ˜0.5 nm Hz-1/2 with a minimum uncertainty of 1.7 nm, allowing the direct imaging of atomic motion. This is the highest position sensitivity ever measured for an isolated atom and opens up the possibility of performing out-of-focus three-dimensional particle tracking, imaging of atoms in three-dimensional optical lattices or sensing forces at the yoctonewton (10-24 N) scale.

  1. Quantitative and qualitative image quality analysis of super resolution images from a low cost scanning laser ophthalmoscope

    Science.gov (United States)

    Murillo, Sergio; Echegaray, Sebastian; Zamora, Gilberto; Soliz, Peter; Bauman, Wendall

    2011-03-01

    The lurking epidemic of eye diseases caused by diabetes and aging will put more than 130 million Americans at risk of blindness by 2020. Screening has been touted as a means to prevent blindness by identifying those individuals at risk. However, the cost of most of today's commercial retinal imaging devices makes their use economically impractical for mass screening. Thus, low cost devices are needed. With these devices, low cost often comes at the expense of image quality with high levels of noise and distortion hindering the clinical evaluation of those retinas. A software-based super resolution (SR) reconstruction methodology that produces images with improved resolution and quality from multiple low resolution (LR) observations is introduced. The LR images are taken with a low-cost Scanning Laser Ophthalmoscope (SLO). The non-redundant information of these LR images is combined to produce a single image in an implementation that also removes noise and imaging distortions while preserving fine blood vessels and small lesions. The feasibility of using the resulting SR images for screening of eye diseases was tested using quantitative and qualitative assessments. Qualitatively, expert image readers evaluated their ability of detecting clinically significant features on the SR images and compared their findings with those obtained from matching images of the same eyes taken with commercially available high-end cameras. Quantitatively, measures of image quality were calculated from SR images and compared to subject-matched images from a commercial fundus imager. Our results show that the SR images have indeed enough quality and spatial detail for screening purposes.

  2. Resolution enhancement in digital x-ray imaging

    International Nuclear Information System (INIS)

    We have developed a restoration method for radiographs that enhances image sharpness and reveals bone microstructures that were initially hidden in the soft-tissue glare. The method is two fold: the image is first deconvolved using the Richardson-Lucy algorithm and is then divided with a signal modelling the soft-tissue distribution to increase the overall contrast. Each step has its own merits but the power of the restoration method lies in their combination. The originality of the method is its reliance on a priori information at each step in the processing. We have measured and modelled analytically the point-spread function of a low-dose gas microstrip x-ray detector at several beam energies. We measured the relationship between the local image intensity and the noise variance for these images. The soft-tissue signal was also modelled using a minimum-curvature filtering technique. These results were then combined into an image deconvolution procedure that uses wavelet filtering to reduce restoration noise while keeping the enhanced small-scale features. The method was applied successfully to images of a human-torso phantom and improved the contrast of small details on the bones and in the soft tissues. We measured a mean 54% increase in signal to noise ratio and a mean 105% increase in contrast to noise ratio in the 70 and 140 kVp images we analysed. The method was designed to facilitate the analysis of radiographs by relying on two levels of visual inspection. The contrast of the full image is first enhanced by division with the signal modelling the soft-tissue distribution. Based on the result, a radiologist might decide to zoom in on a given image section. The full restoration method is then applied to that region of interest. Indeed, full image deconvolution is often unnecessary since enhanced small-scale details are not visible at large scale; only the section of interest is processed which is more efficient

  3. Large-Scale Multi-Resolution Representations for Accurate Interactive Image and Volume Operations

    KAUST Repository

    Sicat, Ronell B.

    2015-11-25

    The resolutions of acquired image and volume data are ever increasing. However, the resolutions of commodity display devices remain limited. This leads to an increasing gap between data and display resolutions. To bridge this gap, the standard approach is to employ output-sensitive operations on multi-resolution data representations. Output-sensitive operations facilitate interactive applications since their required computations are proportional only to the size of the data that is visible, i.e., the output, and not the full size of the input. Multi-resolution representations, such as image mipmaps, and volume octrees, are crucial in providing these operations direct access to any subset of the data at any resolution corresponding to the output. Despite its widespread use, this standard approach has some shortcomings in three important application areas, namely non-linear image operations, multi-resolution volume rendering, and large-scale image exploration. This dissertation presents new multi-resolution representations for large-scale images and volumes that address these shortcomings. Standard multi-resolution representations require low-pass pre-filtering for anti- aliasing. However, linear pre-filters do not commute with non-linear operations. This becomes problematic when applying non-linear operations directly to any coarse resolution levels in standard representations. Particularly, this leads to inaccurate output when applying non-linear image operations, e.g., color mapping and detail-aware filters, to multi-resolution images. Similarly, in multi-resolution volume rendering, this leads to inconsistency artifacts which manifest as erroneous differences in rendering outputs across resolution levels. To address these issues, we introduce the sparse pdf maps and sparse pdf volumes representations for large-scale images and volumes, respectively. These representations sparsely encode continuous probability density functions (pdfs) of multi-resolution pixel

  4. Imaging live cells at high spatiotemporal resolution for lab-on-a-chip applications.

    Science.gov (United States)

    Chin, Lip Ket; Lee, Chau-Hwang; Chen, Bi-Chang

    2016-05-24

    Conventional optical imaging techniques are limited by the diffraction limit and difficult-to-image biomolecular and sub-cellular processes in living specimens. Novel optical imaging techniques are constantly evolving with the desire to innovate an imaging tool that is capable of seeing sub-cellular processes in a biological system, especially in three dimensions (3D) over time, i.e. 4D imaging. For fluorescence imaging on live cells, the trade-offs among imaging depth, spatial resolution, temporal resolution and photo-damage are constrained based on the limited photons of the emitters. The fundamental solution to solve this dilemma is to enlarge the photon bank such as the development of photostable and bright fluorophores, leading to the innovation in optical imaging techniques such as super-resolution microscopy and light sheet microscopy. With the synergy of microfluidic technology that is capable of manipulating biological cells and controlling their microenvironments to mimic in vivo physiological environments, studies of sub-cellular processes in various biological systems can be simplified and investigated systematically. In this review, we provide an overview of current state-of-the-art super-resolution and 3D live cell imaging techniques and their lab-on-a-chip applications, and finally discuss future research trends in new and breakthrough research areas of live specimen 4D imaging in controlled 3D microenvironments.

  5. Imaging live cells at high spatiotemporal resolution for lab-on-a-chip applications.

    Science.gov (United States)

    Chin, Lip Ket; Lee, Chau-Hwang; Chen, Bi-Chang

    2016-05-24

    Conventional optical imaging techniques are limited by the diffraction limit and difficult-to-image biomolecular and sub-cellular processes in living specimens. Novel optical imaging techniques are constantly evolving with the desire to innovate an imaging tool that is capable of seeing sub-cellular processes in a biological system, especially in three dimensions (3D) over time, i.e. 4D imaging. For fluorescence imaging on live cells, the trade-offs among imaging depth, spatial resolution, temporal resolution and photo-damage are constrained based on the limited photons of the emitters. The fundamental solution to solve this dilemma is to enlarge the photon bank such as the development of photostable and bright fluorophores, leading to the innovation in optical imaging techniques such as super-resolution microscopy and light sheet microscopy. With the synergy of microfluidic technology that is capable of manipulating biological cells and controlling their microenvironments to mimic in vivo physiological environments, studies of sub-cellular processes in various biological systems can be simplified and investigated systematically. In this review, we provide an overview of current state-of-the-art super-resolution and 3D live cell imaging techniques and their lab-on-a-chip applications, and finally discuss future research trends in new and breakthrough research areas of live specimen 4D imaging in controlled 3D microenvironments. PMID:27121367

  6. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

    OpenAIRE

    Kakinuma, Ryutaro; Moriyama, Noriyuki; Muramatsu, Yukio; Gomi, Shiho; Suzuki, Masahiro; Nagasawa, Hirobumi; Kusumoto, Masahiko; Aso, Tomohiko; Muramatsu, Yoshihisa; Tsuchida, Takaaki; Tsuta, Koji; Maeshima, Akiko Miyagi; Tochigi, Naobumi; Watanabe, Shun-ichi; SUGIHARA, Naoki

    2015-01-01

    Purpose: The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods: This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm × 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm × 16 or 0.5 mm × 64 detector-row CT scanner operating at 150 mAs. Images fr...

  7. Ultra-High-Resolution Computed Tomography of the Lung: Image Quality of a Prototype Scanner

    OpenAIRE

    Ryutaro Kakinuma; Noriyuki Moriyama; Yukio Muramatsu; Shiho Gomi; Masahiro Suzuki; Hirobumi Nagasawa; Masahiko Kusumoto; Tomohiko Aso; Yoshihisa Muramatsu; Takaaki Tsuchida; Koji Tsuta; Akiko Miyagi Maeshima; Naobumi Tochigi; Shun-Ichi Watanabe; Naoki Sugihara

    2015-01-01

    Purpose The image noise and image quality of a prototype ultra-high-resolution computed tomography (U-HRCT) scanner was evaluated and compared with those of conventional high-resolution CT (C-HRCT) scanners. Materials and Methods This study was approved by the institutional review board. A U-HRCT scanner prototype with 0.25 mm x 4 rows and operating at 120 mAs was used. The C-HRCT images were obtained using a 0.5 mm x 16 or 0.5 mm x 64 detector-row CT scanner operating at 150 mAs. Images from...

  8. High Resolution Global Topography of Eros from NEAR Imaging and LIDAR Data

    Science.gov (United States)

    Gaskell, Robert W.; Konopliv, A.; Barnouin-Jha, O.; Scheeres, D.

    2006-01-01

    Principal Data Products: Ensemble of L-maps from SPC, Spacecraft state, Asteroid pole and rotation. Secondary Products: Global topography model, inertia tensor, gravity. Composite high resolution topography. Three dimensional image maps.

  9. On-demand optical immobilization of Caenorhabditis elegans for high-resolution imaging and microinjection.

    Science.gov (United States)

    Hwang, Hyundoo; Krajniak, Jan; Matsunaga, Yohei; Benian, Guy M; Lu, Hang

    2014-09-21

    This paper describes a novel selective immobilization technique based on optical control of the sol-gel transition of thermoreversible Pluronic gel, which provides a simple, versatile, and biocompatible approach for high-resolution imaging and microinjection of Caenorhabditis elegans.

  10. High Spectral Resolution, High Cadence, Imaging X-ray Microcalorimeters for Solar Physics - Phase 2 Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Microcalorimeter x-ray instruments are non-dispersive, high spectral resolution, broad-band, high cadence imaging spectrometers. We have been developing these...

  11. A joint compressed-sensing and super-resolution approach for very high-resolution diffusion imaging.

    Science.gov (United States)

    Ning, Lipeng; Setsompop, Kawin; Michailovich, Oleg; Makris, Nikos; Shenton, Martha E; Westin, Carl-Fredrik; Rathi, Yogesh

    2016-01-15

    Diffusion MRI (dMRI) can provide invaluable information about the structure of different tissue types in the brain. Standard dMRI acquisitions facilitate a proper analysis (e.g. tracing) of medium-to-large white matter bundles. However, smaller fiber bundles connecting very small cortical or sub-cortical regions cannot be traced accurately in images with large voxel sizes. Yet, the ability to trace such fiber bundles is critical for several applications such as deep brain stimulation and neurosurgery. In this work, we propose a novel acquisition and reconstruction scheme for obtaining high spatial resolution dMRI images using multiple low resolution (LR) images, which is effective in reducing acquisition time while improving the signal-to-noise ratio (SNR). The proposed method called compressed-sensing super resolution reconstruction (CS-SRR), uses multiple overlapping thick-slice dMRI volumes that are under-sampled in q-space to reconstruct diffusion signal with complex orientations. The proposed method combines the twin concepts of compressed sensing and super-resolution to model the diffusion signal (at a given b-value) in a basis of spherical ridgelets with total-variation (TV) regularization to account for signal correlation in neighboring voxels. A computationally efficient algorithm based on the alternating direction method of multipliers (ADMM) is introduced for solving the CS-SRR problem. The performance of the proposed method is quantitatively evaluated on several in-vivo human data sets including a true SRR scenario. Our experimental results demonstrate that the proposed method can be used for reconstructing sub-millimeter super resolution dMRI data with very good data fidelity in clinically feasible acquisition time.

  12. High-resolution radio imaging of young supernovae

    CERN Document Server

    Pérez-Torres, M A; Alberdi, A; Ros, E; Guirado, J C; Lara, L; Mantovani, F; Stockdale, C J; Weiler, K W; Diamond, P J; Van Dyk, S D; Lundqvist, P; Panagia, N; Shapiro, I I; Sramek, R

    2004-01-01

    The high resolution obtained through the use of VLBI gives an unique opportunity to directly observe the interaction of an expanding radio supernova with its surrounding medium. We present here results from our VLBI observations of the young supernovae SN 1979C, SN 1986J, and SN 2001gd.

  13. Source camera identification for low resolution heavily compressed images

    NARCIS (Netherlands)

    E.J. Alles; Z.J.M.H. Geradts; C.J. Veenman

    2008-01-01

    In this paper, we propose a method to exploit photo response non-uniformity (PRNU) to identify the source camera of heavily JPEG compressed digital photographs of resolution 640 times 480 pixels. Similarly to research reported previously, we extract the PRNU patterns from both reference and question

  14. Super Resolution Reconstruction Based on Adaptive Detail Enhancement for ZY-3 Satellite Images

    Science.gov (United States)

    Zhu, Hong; Song, Weidong; Tan, Hai; Wang, Jingxue; Jia, Di

    2016-06-01

    Super-resolution reconstruction of sequence remote sensing image is a technology which handles multiple low-resolution satellite remote sensing images with complementary information and obtains one or more high resolution images. The cores of the technology are high precision matching between images and high detail information extraction and fusion. In this paper puts forward a new image super resolution model frame which can adaptive multi-scale enhance the details of reconstructed image. First, the sequence images were decomposed into a detail layer containing the detail information and a smooth layer containing the large scale edge information by bilateral filter. Then, a texture detail enhancement function was constructed to promote the magnitude of the medium and small details. Next, the non-redundant information of the super reconstruction was obtained by differential processing of the detail layer, and the initial super resolution construction result was achieved by interpolating fusion of non-redundant information and the smooth layer. At last, the final reconstruction image was acquired by executing a local optimization model on the initial constructed image. Experiments on ZY-3 satellite images of same phase and different phase show that the proposed method can both improve the information entropy and the image details evaluation standard comparing with the interpolation method, traditional TV algorithm and MAP algorithm, which indicate that our method can obviously highlight image details and contains more ground texture information. A large number of experiment results reveal that the proposed method is robust and universal for different kinds of ZY-3 satellite images.

  15. Spatial resolution of a {\\mu}PIC-based neutron imaging detector

    OpenAIRE

    Parker, Joseph D.; Harada, Masahide; Hattori, Kaori; Iwaki, Satoru; Kabuki, Shigeto; Kishimoto, Yuji; Kubo, Hidetoshi; Kurosawa, Shunsuke; Matsuoka, Yoshihiro; Miuchi, Kentaro; Mizumoto, Tetsuya; Nishimura, Hironobu; Oku, Takayuki; Sawano, Tatsuya; Shinohara, Takenao

    2013-01-01

    We present a detailed study of the spatial resolution of our time-resolved neutron imaging detector utilizing a new neutron position reconstruction method that improves both spatial resolution and event reconstruction efficiency. Our prototype detector system, employing a micro-pattern gaseous detector known as the micro-pixel chamber ({\\mu}PIC) coupled with a field-programmable-gate-array-based data acquisition system, combines 100{\\mu}m-level spatial and sub-{\\mu}s time resolutions with exc...

  16. A condition on the spatial resolution of IR collimators for testing of thermal imaging systems

    Science.gov (United States)

    Chrzanowski, Krzysztof; Lee, Hee Chul; Wrona, Wieslaw

    2000-05-01

    A precise condition on the spatial resolution of the IR collimator for testing thermal imaging systems is presented. The condition can be used even if only the spatial resolution of the IR collimator and that of the system under test, measured using popular definitions, are known. It is shown that when the condition is fulfilled, the thermal image degradation caused by the IR collimator is negligible.

  17. The origin of high-resolution IETS-STM images of organic molecules with functionalized tips

    OpenAIRE

    Hapalpa, Prokop; Temirov, Ruslan; Tautz, Stefan; Jelinek, Pavel

    2014-01-01

    Recently, the family of high-resolution scanning probe imaging techniques using decorated tips has been complimented by a method based on inelastic electron tunneling spectroscopy (IETS). The new technique resolves the inner structure of organic molecules by mapping the vibrational energy of a single carbonmonoxide (CO) molecule positioned at the apex of a scanning tunnelling microscope (STM) tip. Here, we explain high-resolution IETS imaging by extending the model developed earlier for STM a...

  18. Atomic resolution imaging at 2.5 GHz using near-field microwave microscopy

    OpenAIRE

    Lee, Jonghee; Long, Christian J.; Yang, Haitao; Xiang, Xiao-Dong; Takeuchi, Ichiro

    2010-01-01

    Atomic resolution imaging is demonstrated using a hybrid scanning tunneling/near-field microwave microscope (microwave-STM). The microwave channels of the microscope correspond to the resonant frequency and quality factor of a coaxial microwave resonator, which is built in to the STM scan head and coupled to the probe tip. We find that when the tip-sample distance is within the tunneling regime, we obtain atomic resolution images using the microwave channels of the microwave-STM. We attribute...

  19. Framework for reliable, real-time facial expression recognition for low resolution images

    OpenAIRE

    Khan, Rizwan Ahmed; Meyer, Alexandre; Konik, Hubert; Bouakaz, Saïda

    2013-01-01

    International audience Automatic recognition of facial expressions is a challenging problem specially for low spatial resolution facial images. It has many potential applications in human-computer interactions, social robots, deceit detection, interactive video and behavior monitoring. In this study we present a novel framework that can recognize facial expressions very efficiently and with high accuracy even for very low resolution facial images. The proposed framework is memory and time ...

  20. Terahertz imaging with sub-wavelength resolution by femtosecond laser filament in air

    CERN Document Server

    Zhao, Jiayu; Guo, Lanjun; Wang, Zhi; Cheng, Ya; Liu, Weiwei; Xu, Zhizhan

    2013-01-01

    Terahertz (THz) imaging provides cutting edge technique in biology, medical sciences and non-destructive evaluation. However, due to the long wavelength of the THz wave, the obtained resolution of THz imaging is normally a few hundred microns and is much lower than that of the traditional optical imaging. We introduce a sub-wavelength resolution THz imaging technique which uses the THz radiation generated by a femtosecond laser filament in air as the probe. This method is based on the fact that the femtosecond laser filament forms a waveguide for the THz wave in air. The diameter of the THz beam, which propagates inside the filament, varies from 20 {\\mu}m to 50 {\\mu}m, which is significantly smaller than the wavelength of the THz wave. Using this highly spatially confined THz beam as the probe, THz imaging with resolution as high as 20 {\\mu}m (~{\\lambda}/38) can be realized.

  1. Sparse PDF maps for non-linear multi-resolution image operations

    KAUST Repository

    Hadwiger, Markus

    2012-11-01

    We introduce a new type of multi-resolution image pyramid for high-resolution images called sparse pdf maps (sPDF-maps). Each pyramid level consists of a sparse encoding of continuous probability density functions (pdfs) of pixel neighborhoods in the original image. The encoded pdfs enable the accurate computation of non-linear image operations directly in any pyramid level with proper pre-filtering for anti-aliasing, without accessing higher or lower resolutions. The sparsity of sPDF-maps makes them feasible for gigapixel images, while enabling direct evaluation of a variety of non-linear operators from the same representation. We illustrate this versatility for antialiased color mapping, O(n) local Laplacian filters, smoothed local histogram filters (e.g., median or mode filters), and bilateral filters. © 2012 ACM.

  2. Large area super-resolution chemical imaging via rapid dithering of a nanoprobe

    Science.gov (United States)

    Languirand, Eric R.; Cullum, Brian M.

    2015-05-01

    Super-resolution chemical imaging via Raman spectroscopy provides a significant ability to simultaneously or pseudosimultaneously monitor numerous label-free analytes while elucidating their spatial distribution on the surface of the sample. However, spontaneous Raman is an inherently weak phenomenon making trace detection and thus superresolution imaging extremely difficult, if not impossible. To circumvent this and allow for trace detection of the few chemical species present in any sub-diffraction limited resolution element of an image, we have developed a surface enhanced Raman scattering (SERS) coherent fiber-optic imaging bundle probe consisting of 30,000 individual fiber elements. When the probes are tapered, etched and coated with metal, they provide circular Raman chemical images of a sample with a field of view of approximately 20μm (i.e. diameter) via the array of 30,000 individual 50 nm fiber elements. An acousto-optic tunable filter is used to rapidly scan or select discrete frequencies for multi- or hyperspectral analysis. Although the 50nm fiber element dimensions of this probe inherently provide spatial resolutions of approximately 100nm, further increases in the spatial resolution can be achieved by using a rapid dithering process. Using this process, additional images are obtained one-half fiber diameter translations in the x- and y- planes. A piezostage drives the movement, providing the accurate and reproducible shifts required for dithering. Optimal probability algorithms are then used to deconvolute the related images producing a final image with a three-fold increase in spatial resolution. This paper describes super-resolution chemical imaging using these probes and the dithering method as well as its potential applications in label-free imaging of lipid rafts and other applications within biology and forensics.

  3. Information Extraction of High Resolution Remote Sensing Images Based on the Calculation of Optimal Segmentation Parameters.

    Science.gov (United States)

    Zhu, Hongchun; Cai, Lijie; Liu, Haiying; Huang, Wei

    2016-01-01

    Multi-scale image segmentation and the selection of optimal segmentation parameters are the key processes in the object-oriented information extraction of high-resolution remote sensing images. The accuracy of remote sensing special subject information depends on this extraction. On the basis of WorldView-2 high-resolution data, the optimal segmentation parameters methodof object-oriented image segmentation and high-resolution image information extraction, the following processes were conducted in this study. Firstly, the best combination of the bands and weights was determined for the information extraction of high-resolution remote sensing image. An improved weighted mean-variance method was proposed andused to calculatethe optimal segmentation scale. Thereafter, the best shape factor parameter and compact factor parameters were computed with the use of the control variables and the combination of the heterogeneity and homogeneity indexes. Different types of image segmentation parameters were obtained according to the surface features. The high-resolution remote sensing images were multi-scale segmented with the optimal segmentation parameters. Ahierarchical network structure was established by setting the information extraction rules to achieve object-oriented information extraction. This study presents an effective and practical method that can explain expert input judgment by reproducible quantitative measurements. Furthermore the results of this procedure may be incorporated into a classification scheme.

  4. Super-resolution of hyperspectral images using sparse representation and Gabor prior

    Science.gov (United States)

    Patel, Rakesh C.; Joshi, Manjunath V.

    2016-04-01

    Super-resolution (SR) as a postprocessing technique is quite useful in enhancing the spatial resolution of hyperspectral (HS) images without affecting its spectral resolution. We present an approach to increase the spatial resolution of HS images by making use of sparse representation and Gabor prior. The low-resolution HS observations consisting of large number of bands are represented as a linear combination of a small number of basis images using principal component analysis (PCA), and the significant components are used in our work. We first obtain initial estimates of SR on this reduced dimension by using compressive sensing-based method. Since SR is an ill-posed problem, the final solution is obtained by using a regularization framework. The novelty of our approach lies in: (1) estimation of optimal point spread function in the form of decimation matrix, and (2) using a new prior called "Gabor prior" to super-resolve the significant PCA components. Experiments are conducted on two different HS datasets namely, 31-band natural HS image set collected under controlled laboratory environment and a set of 224-band real HS images collected by airborne visible/infrared imaging spectrometer remote sensing sensor. Visual inspections and quantitative comparison confirm that our method enhances spatial information without introducing significant spectral distortion. Our conclusions include: (1) incorporate the sensor characteristics in the form of estimated decimation matrix for SR, and (2) preserve various frequencies in super-resolved image by making use of Gabor prior.

  5. High resolution imaging with TM01 laser beams

    Science.gov (United States)

    Dehez, Harold; Piché, Michel; De Koninck, Yves

    2009-06-01

    Using the vectorial diffraction theory established by Richards and Wolf, we demonstrate that the resolution of a two-photon microscope can be improved with a radially polarized TM01 laser beam and an interface between dielectrics, instead of the linearly polarized Gaussian beam already used in laser scanning microscopy. To verify the theoretical results, we developed a mode converter producing radially polarized beams and we have integrated it in a commercial two-photon microscope.

  6. Ultra-sensitive and super-resolving angular rotation measurement based on photon orbital angular momentum using parity measurement.

    Science.gov (United States)

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan

    2016-08-15

    Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss.

  7. Ultra-sensitive and super-resolving angular rotation measurement based on photon orbital angular momentum using parity measurement.

    Science.gov (United States)

    Zhang, Zijing; Qiao, Tianyuan; Ma, Kun; Cen, Longzhu; Zhang, Jiandong; Wang, Feng; Zhao, Yuan

    2016-08-15

    Photon orbital angular momentum has led to many novel insights and applications in quantum measurement. Photon orbital angular momentum can increase the resolution and sensitivity of angular rotation measurement. However, quantum measurement strategy can further surpass this limit and improve the resolution of angular rotation measurement. This Letter proposes and demonstrates a parity measurement method in angular rotation measurement scheme for the first time. Parity measurement can make the resolution superior to the limit of the existing method. The sensitivity can be improved with higher orbital angular momentum photons. Moreover, this Letter gives a detailed discussion of the change of resolution and sensitivity in the presence of photon loss. PMID:27519107

  8. High-resolution retinal imaging using adaptive optics and Fourier-domain optical coherence tomography

    Science.gov (United States)

    Olivier, Scot S.; Werner, John S.; Zawadzki, Robert J.; Laut, Sophie P.; Jones, Steven M.

    2010-09-07

    This invention permits retinal images to be acquired at high speed and with unprecedented resolution in three dimensions (4.times.4.times.6 .mu.m). The instrument achieves high lateral resolution by using adaptive optics to correct optical aberrations of the human eye in real time. High axial resolution and high speed are made possible by the use of Fourier-domain optical coherence tomography. Using this system, we have demonstrated the ability to image microscopic blood vessels and the cone photoreceptor mosaic.

  9. Detecting breast microcalcifications using super-resolution and wave-equation ultrasound imaging: a numerical phantom study

    Science.gov (United States)

    Huang, Lianjie; Simonetti, Francesco; Huthwaite, Peter; Rosenberg, Robert; Williamson, Michael

    2010-03-01

    Ultrasound image resolution and quality need to be significantly improved for breast microcalcification detection. Super-resolution imaging with the factorization method has recently been developed as a promising tool to break through the resolution limit of conventional imaging. In addition, wave-equation reflection imaging has become an effective method to reduce image speckles by properly handling ultrasound scattering/diffraction from breast heterogeneities during image reconstruction. We explore the capabilities of a novel super-resolution ultrasound imaging method and a wave-equation reflection imaging scheme for detecting breast microcalcifications. Super-resolution imaging uses the singular value decomposition and a factorization scheme to achieve an image resolution that is not possible for conventional ultrasound imaging. Wave-equation reflection imaging employs a solution to the acoustic-wave equation in heterogeneous media to backpropagate ultrasound scattering/diffraction waves to scatters and reconstruct images of heterogeneities. We construct numerical breast phantoms using in vivo breast images, and use a finite-difference wave-equation scheme to generate ultrasound data scattered from inclusions that mimic microcalcifications. We demonstrate that microcalcifications can be detected at full spatial resolution using the super-resolution ultrasound imaging and wave-equation reflection imaging methods.

  10. Detecting breast microcalcifications using super-resolution and wave-equation ultrasound imaging: a numerical phantom study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Lianjie [Los Alamos National Laboratory; Simonetti, Francesco [IMPERIAL COLLEGE LONDON; Huthwaite, Peter [IMPERIAL COLLEGE LONDON; Rosenberg, Robert [UNM; Williamson, Michael [UNM

    2010-01-01

    Ultrasound image resolution and quality need to be significantly improved for breast microcalcification detection. Super-resolution imaging with the factorization method has recently been developed as a promising tool to break through the resolution limit of conventional imaging. In addition, wave-equation reflection imaging has become an effective method to reduce image speckles by properly handling ultrasound scattering/diffraction from breast heterogeneities during image reconstruction. We explore the capabilities of a novel super-resolution ultrasound imaging method and a wave-equation reflection imaging scheme for detecting breast microcalcifications. Super-resolution imaging uses the singular value decomposition and a factorization scheme to achieve an image resolution that is not possible for conventional ultrasound imaging. Wave-equation reflection imaging employs a solution to the acoustic-wave equation in heterogeneous media to backpropagate ultrasound scattering/diffraction waves to scatters and form images of heterogeneities. We construct numerical breast phantoms using in vivo breast images, and use a finite-difference wave-equation scheme to generate ultrasound data scattered from inclusions that mimic microcalcifications. We demonstrate that microcalcifications can be detected at full spatial resolution using the super-resolution ultrasound imaging and wave-equation reflection imaging methods.

  11. High-resolution MRI of spinal cords by compressive sensing parallel imaging.

    Science.gov (United States)

    Peng Li; Xiangdong Yu; Griffin, Jay; Levine, Jonathan M; Jim Ji

    2015-08-01

    Spinal Cord Injury (SCI) is a common injury due to diseases or accidents. Noninvasive imaging methods play a critical role in diagnosing SCI and monitoring the response to therapy. Magnetic Resonance Imaging (MRI), by the virtue of providing excellent soft tissue contrast, is the most promising imaging method for this application. However, spinal cord has a very small cross-section, which needs high-resolution images for better visualization and diagnosis. Acquiring high-resolution spinal cord MRI images requires long acquisition time due to the physical and physiological constraints. Moreover, long acquisition time makes MRI more susceptible to motion artifacts. In this paper, we studied the application of compressive sensing (CS) and parallel imaging to achieve high-resolution imaging from sparsely sampled and reduced k-space data acquired by parallel receive arrays. In particular, the studies are limited to the effects of 2D Cartesian sampling with different subsampling schemes and reduction factors. The results show that compressive sensing parallel MRI has the potential to provide high-resolution images of the spinal cord in 1/3 of the acquisition time required by the conventional methods.

  12. Submolecular Resolution Imaging of molecules by Atomic Force Microscopy:The influence of the Electrostatic Force

    NARCIS (Netherlands)

    van der Lit, J.; Cicco, F.; Hapala, P.; Jelinek, P.; Swart, Ingmar

    2016-01-01

    The forces governing the contrast in submolecular resolution imaging of molecules with atomic force microscopy (AFM) have recently become a topic of intense debate. Here, we show that the electrostatic force is essential to understand the contrast in atomically resolved AFM images of polar molecules

  13. Widefield Microwave Imaging in Alkali Vapor Cells with sub-100 um Resolution

    CERN Document Server

    Horsley, Andrew; Treutlein, Philipp

    2015-01-01

    We report on widefield microwave vector field imaging with sub um resolution using a microfabricated alkali vapor cell. The setup can additionally image dc magnetic fields, and can be configured to image microwave electric fields. Our camera-based widefield imaging system records 2D images with a 6x6 mm2 field of view at a rate of 10 Hz. It provides up to 50 um spatial resolution, and allows imaging of fields as close as 150 um above structures, through the use of thin external cell walls. This is crucial in allowing us to take practical advantage of the high spatial resolution, as feature sizes in near-fields are on the order of the distance from their source, and represents an order of magnitude improvement in surface-feature resolution compared to previous vapor cell experiments. We present microwave and dc magnetic field images above a selection of devices, demonstrating a microwave sensitivity of 1.4 uT/sqrt-Hz per 50x50x140 um3 voxel, at present limited by the speed of our camera system. Since we image ...

  14. All-passive pixel super-resolution of time-stretch imaging

    CERN Document Server

    Chan, Antony C S; Bogaraju, Sharat C V; So, Hayden K H; Lam, Edmund Y; Tsia, Kevin K

    2016-01-01

    Based on image encoding in a serial-temporal format, optical time-stretch imaging entails a stringent requirement of state-of-the- art fast data acquisition unit in order to preserve high image resolution at an ultrahigh frame rate --- hampering the widespread utilities of such technology. Here, we propose a pixel super-resolution (pixel-SR) technique tailored for time-stretch imaging that preserves pixel resolution at a relaxed sampling rate. It harnesses the subpixel shifts between image frames inherently introduced by asynchronous digital sampling of the continuous time-stretch imaging process. Precise pixel registration is thus accomplished without any active opto-mechanical subpixel-shift control or other additional hardware. Here, we present the experimental pixel-SR image reconstruction pipeline that restores high-resolution time-stretch images of microparticles and biological cells (phytoplankton) at a relaxed sampling rate (approx. 2--5 GSa/s) --- more than four times lower than the originally requir...

  15. FRESH-FRI-Based Single-Image Super-Resolution Algorithm.

    Science.gov (United States)

    Wei, Xiaoyao; Dragotti, Pier Luigi

    2016-08-01

    In this paper, we consider the problem of single image super-resolution and propose a novel algorithm that outperforms state-of-the-art methods without the need of learning patches pairs from external data sets. We achieve this by modeling images and, more precisely, lines of images as piecewise smooth functions and propose a resolution enhancement method for this type of functions. The method makes use of the theory of sampling signals with finite rate of innovation (FRI) and combines it with traditional linear reconstruction methods. We combine the two reconstructions by leveraging from the multi-resolution analysis in wavelet theory and show how an FRI reconstruction and a linear reconstruction can be fused using filter banks. We then apply this method along vertical, horizontal, and diagonal directions in an image to obtain a single-image super-resolution algorithm. We also propose a further improvement of the method based on learning from the errors of our super-resolution result at lower resolution levels. Simulation results show that our method outperforms state-of-the-art algorithms under different blurring kernels. PMID:27168595

  16. Coherent diffractive imaging of time-evolving samples with improved temporal resolution

    Energy Technology Data Exchange (ETDEWEB)

    Ulvestad, A.; Tripathi, A.; Hruszkewycz, S. O.; Cha, W.; Wild, S. M.; Stephenson, G. B.; Fuoss, P. H.

    2016-05-19

    Bragg coherent x-ray diffractive imaging is a powerful technique for investigating dynamic nanoscale processes in nanoparticles immersed in reactive, realistic environments. Its temporal resolution is limited, however, by the oversampling requirements of three-dimensional phase retrieval. Here, we show that incorporating the entire measurement time series, which is typically a continuous physical process, into phase retrieval allows the oversampling requirement at each time step to be reduced, leading to a subsequent improvement in the temporal resolution by a factor of 2-20 times. The increased time resolution will allow imaging of faster dynamics and of radiation-dose-sensitive samples. This approach, which we call "chrono CDI," may find use in improving the time resolution in other imaging techniques.

  17. Super-resolution imaging in digital holography by using dynamic grating with a spatial light modulator

    Science.gov (United States)

    Lin, Qiaowen; Wang, Dayong; Wang, Yunxin; Rong, Lu; Chang, Shifeng

    2015-03-01

    A super-resolution imaging method using dynamic grating based on liquid-crystal spatial light modulator (SLM) is developed to improve the resolution of a digital holographic system. The one-dimensional amplitude cosine grating is loaded on the SLM, which is placed between the object and hologram plane in order to collect more high-frequency components towards CCD plane. The point spread function of the system is given to confirm the separation condition of reconstructed images for multiple diffraction orders. The simulation and experiments are carried out for a standard resolution test target as a sample, which confirms that the imaging resolution is improved from 55.7 μm to 31.3 μm compared with traditional lensless Fourier transform digital holography. The unique advantage of the proposed method is that the period of the grating can be programmably adjusted according to the separation condition.

  18. Nonparametric Bayesian Clustering of Structural Whole Brain Connectivity in Full Image Resolution

    DEFF Research Database (Denmark)

    Ambrosen, Karen Marie Sandø; Albers, Kristoffer Jon; Dyrby, Tim B.;

    2014-01-01

    groups) that defines structural units at the resolution of statistical support. We apply the model to a network of structural brain connectivity in full image resolution with more than one hundred thousand regions (voxels in the gray-white matter boundary) and around one hundred million connections......Diffusion magnetic resonance imaging enables measuring the structural connectivity of the human brain at a high spatial resolution. Local noisy connectivity estimates can be derived using tractography approaches and statistical models are necessary to quantify the brain’s salient structural....... The derived clustering identifies in the order of one thousand salient structural units and we find that the identified units provide better predictive performance than predicting using the full graph or two commonly used atlases. Extracting structural units of brain connectivity at the full image resolution...

  19. High-resolution synthetic aperture ultrasound imaging with minimum variance beamforming and spiking deconvolution

    Science.gov (United States)

    Shin, Junseob; Huang, Lianjie

    2016-04-01

    Minimum variance beamforming (MVBF) is an adaptive beamforming technique, which aims to improve the lateral resolution by computing and applying signal-dependent apodization rather than predetermined apodization as typically done in conventional delay-and-sum (DAS) beamforming. Although studies have shown that the improvement in lateral resolution associated with MVBF is significant, the axial resolution remains unaffected. In this work, we combine MVBF and spiking deconvolution to improve both lateral and axial resolutions in synthetic aperture ultrasound imaging. We implement our new method and evaluate its performance using experimental datasets from a tissue-mimicking phantom. Our results show that our new method yields improved axial and lateral resolutions as well as image contrast.

  20. Fast, High-Resolution Terahertz Radar Imaging at 25 Meters

    Science.gov (United States)

    Cooper, Ken B.; Dengler, Robert J.; Llombart, Nuria; Talukder, Ashit; Panangadan, Anand V.; Peay, Chris S.; Siegel, Peter H.

    2010-01-01

    We report improvements in the scanning speed and standoff range of an ultra-wide bandwidth terahertz (THz) imaging radar for person-borne concealed object detection. Fast beam scanning of the single-transceiver radar is accomplished by rapidly deflecting a flat, light-weight subreflector in a confocal Gregorian optical geometry. With RF back-end improvements also implemented, the radar imaging rate has increased by a factor of about 30 compared to that achieved previously in a 4 m standoff prototype instrument. In addition, a new 100 cm diameter ellipsoidal aluminum reflector yields beam spot diameters of approximately 1 cm over a 50x50 cm field of view at a range of 25 m, although some aberrations are observed that probably arise from misaligned optics. Through-clothes images of a concealed threat at 25 m range, acquired in 5 seconds, are presented, and the impact of reduced signal-to-noise from an even faster frame rate is analyzed. These results inform the system requirements for eventually achieving sub-second or video-rate THz radar imaging.