WorldWideScience

Sample records for dynamic insar imaging

  1. Advanced InSAR imaging for dune mapping

    Science.gov (United States)

    Havivi, Shiran; August, Yitzhak; Blumberg, Dan G.; Rotman, Stanley R.

    2015-04-01

    Aeolian morphologies are formed in the presence of sufficient wind energy and available particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970's, remote sensing imagery both optical and radar, are used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of Aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two images or more. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This research aims to demonstrate how interferometric decorrelation, or, coherence change detection, can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the Nitzanim coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of varying levels of stability and vegetation cover and have been monitored meteorologically, geomorphologically and

  2. Semantic Interpretation of Insar Estimates Using Optical Images with Application to Urban Infrastructure Monitoring

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    Wang, Y.; Zhu, X. X.

    2015-08-01

    Synthetic aperture radar interferometry (InSAR) has been an established method for long term large area monitoring. Since the launch of meter-resolution spaceborne SAR sensors, the InSAR community has shown that even individual buildings can be monitored in high level of detail. However, the current deformation analysis still remains at a primitive stage of pixel-wise motion parameter inversion and manual identification of the regions of interest. We are aiming at developing an automatic urban infrastructure monitoring approach by combining InSAR and the semantics derived from optical images, so that the deformation analysis can be done systematically in the semantic/object level. This paper explains how we transfer the semantic meaning derived from optical image to the InSAR point clouds, and hence different semantic classes in the InSAR point cloud can be automatically extracted and monitored. Examples on bridges and railway monitoring are demonstrated.

  3. Ka-band InSAR Imaging and Analysis Based on IMU Data

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    Shi Jun

    2014-02-01

    Full Text Available Compared with other bands, the millimeter wave Interferometric Synthetic Aperture Radar (InSAR has high accuracy and small size, which is a hot topic in InSAR research. On the other hand, shorter wavelength causes difficulties in 2D imaging and interferometric phase extraction. In this study, the imaging and phase performance of the streaming Back Projection (BP method combined with IMU data are analyzed and discussed on the basis of actual Ka-band InSAR data. It is found that because the wavelength of the Ka-band is short, it is more sensitive to the antenna phase-center history. To ensure the phase-preserving capacity, the IMU data must be used with accurate motion error compensation. Furthermore, during data processing, we verify the flat-earth-removing capacity of the BP algorithm that calculates and compensates the master and slave antenna phase centers individually.

  4. Improvement of the Accuracy of InSAR Image Co-Registration Based On Tie Points – A Review

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    Xiaoli Ding

    2009-02-01

    Full Text Available Interferometric Synthetic Aperture Radar (InSAR is a new measurement technology, making use of the phase information contained in the Synthetic Aperture Radar (SAR images. InSAR has been recognized as a potential tool for the generation of digital elevation models (DEMs and the measurement of ground surface deformations. However, many critical factors affect the quality of InSAR data and limit its applications. One of the factors is InSAR data processing, which consists of image co-registration, interferogram generation, phase unwrapping and geocoding. The co-registration of InSAR images is the first step and dramatically influences the accuracy of InSAR products. In this paper, the principle and processing procedures of InSAR techniques are reviewed. One of important factors, tie points, to be considered in the improvement of the accuracy of InSAR image co-registration are emphatically reviewed, such as interval of tie points, extraction of feature points, window size for tie point matching and the measurement for the quality of an interferogram.

  5. Assessing groundwater depletion and dynamics using GRACE and InSAR: Potential and limitations

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Galloway, Devin L.; Longuevergne, Laurent; Rivera, Alfonso

    2016-01-01

    In the last decade, remote sensing of the temporal variation of ground level and gravity has improved our understanding of groundwater dynamics and storage. Mass changes are measured by GRACE (Gravity Recovery and Climate Experiment) satellites, whereas ground deformation is measured by processing synthetic aperture radar satellites data using the InSAR (Interferometry of Synthetic Aperture Radar) techniques. Both methods are complementary and offer different sensitivities to aquifer system processes. GRACE is sensitive to mass changes over large spatial scales (more than 100,000 km2). As such, it fails in providing groundwater storage change estimates at local or regional scales relevant to most aquifer systems, and at which most groundwater management schemes are applied. However, InSAR measures ground displacement due to aquifer response to fluid-pressure changes. InSAR applications to groundwater depletion assessments are limited to aquifer systems susceptible to measurable deformation. Furthermore, the inversion of InSAR-derived displacement maps into volume of depleted groundwater storage (both reversible and largely irreversible) is confounded by vertical and horizontal variability of sediment compressibility. During the last decade, both techniques have shown increasing interest in the scientific community to complement available in situ observations where they are insufficient. In this review, we present the theoretical and conceptual bases of each method, and present idealized scenarios to highlight the potential benefits and challenges of combining these techniques to remotely assess groundwater storage changes and other aspects of the dynamics of aquifer systems.

  6. Robust tie points selection for InSAR image coregistration

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    Skanderi, Takieddine; Chabira, Boulerbah; Afifa, Belkacem; Belhadj Aissa, Aichouche

    2013-10-01

    Image coregistration is an important step in SAR interferometry which is a well known method for DEM generation and surface displacement monitoring. A practical and widely used automatic coregistration algorithm is based on selecting a number of tie points in the master image and looking for the correspondence of each point in the slave image using correlation technique. The characteristics of these points, their number and their distribution have a great impact on the reliability of the estimated transformation. In this work, we present a method for automatic selection of suitable tie points that are well distributed over the common area without decreasing the desired tie points' number. First we select candidate points using Harris operator. Then from these points we select tie points depending on their cornerness measure (the highest first). Once a tie point is selected, its correspondence is searched for in the slave image, if the similarity measure maximum is less than a given threshold or it is at the border of the search window, this point is discarded and we proceed to the next Harris point, else, the cornerness of the remaining candidates Harris points are multiplied by a spatially radially increasing function centered at the selected point to disadvantage the points in a neighborhood of a radius determined from the size of the common area and the desired number of points. This is repeated until the desired number of points is selected. Results of an ERS1/2 tandem pair are presented and discussed.

  7. Advanced Interferometric Synthetic Aperture Imaging Radar (InSAR) for Dune Mapping

    Science.gov (United States)

    Havivi, Shiran; Amir, Doron; Schvartzman, Ilan; August, Yitzhak; Mamman, Shimrit; Rotman, Stanely R.; Blumberg, Dan G.

    2016-04-01

    Aeolian morphologies are formed in the presence of sufficient wind energy and available lose particles. These processes occur naturally or are further enhanced or reduced by human intervention. The dimensions of change are dependent primarily on the wind energy and surface properties. Since the 1970s, remote sensing imagery, both optical and radar, have been used for documentation and interpretation of the geomorphologic changes of sand dunes. Remote sensing studies of aeolian morphologies is mostly useful to document major changes, yet, subtle changes, occurring in a period of days or months in scales of centimeters, are very difficult to detect in imagery. Interferometric Synthetic Aperture Radar (InSAR) is an imaging technique for measuring Earth's surface topography and deformation. InSAR images are produced by measuring the radar phase difference between two separated antennas that view the same surface area. Classical InSAR is based on high coherence between two or more images. The output (interferogram) can show subtle changes with an accuracy of several millimeters to centimeters. Very little work has been done on measuring or identifying the changes in dunes using InSAR methods. The reason is that dunes tend to be less coherent than firm, stable, surfaces. This work aims to demonstrate how interferometric decorrelation can be used for identifying dune instability. We hypothesize and demonstrate that the loss of radar coherence over time on dunes can be used as an indication of the dune's instability. When SAR images are acquired at sufficiently close intervals one can measure the time it takes to lose coherence and associate this time with geomorphic stability. To achieve our goals, the coherence change detection method was used, in order to identify dune stability or instability and the dune activity level. The Nitzanim-Ashdod coastal dunes along the Mediterranean, 40 km south of Tel-Aviv, Israel, were chosen as a case study. The dunes in this area are of

  8. Imaging the complex geometry of a magma reservoir using FEM-based linear inverse modeling of InSAR data: application to Rabaul Caldera, Papua New Guinea

    Science.gov (United States)

    Ronchin, Erika; Masterlark, Timothy; Dawson, John; Saunders, Steve; Martì Molist, Joan

    2017-06-01

    We test an innovative inversion scheme using Green's functions from an array of pressure sources embedded in finite-element method (FEM) models to image, without assuming an a-priori geometry, the composite and complex shape of a volcano deformation source. We invert interferometric synthetic aperture radar (InSAR) data to estimate the pressurization and shape of the magma reservoir of Rabaul caldera, Papua New Guinea. The results image the extended shallow magmatic system responsible for a broad and long-term subsidence of the caldera between 2007 February and 2010 December. Elastic FEM solutions are integrated into the regularized linear inversion of InSAR data of volcano surface displacements in order to obtain a 3-D image of the source of deformation. The Green's function matrix is constructed from a library of forward line-of-sight displacement solutions for a grid of cubic elementary deformation sources. Each source is sequentially generated by removing the corresponding cubic elements from a common meshed domain and simulating the injection of a fluid mass flux into the cavity, which results in a pressurization and volumetric change of the fluid-filled cavity. The use of a single mesh for the generation of all FEM models avoids the computationally expensive process of non-linear inversion and remeshing a variable geometry domain. Without assuming an a-priori source geometry other than the configuration of the 3-D grid that generates the library of Green's functions, the geodetic data dictate the geometry of the magma reservoir as a 3-D distribution of pressure (or flux of magma) within the source array. The inversion of InSAR data of Rabaul caldera shows a distribution of interconnected sources forming an amorphous, shallow magmatic system elongated under two opposite sides of the caldera. The marginal areas at the sides of the imaged magmatic system are the possible feeding reservoirs of the ongoing Tavurvur volcano eruption of andesitic products on the

  9. INSAR OF AQUATIC BODIES

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    P. Tarikhi

    2012-07-01

    Full Text Available Radar remote sensing is a new earth observation technology with promising results and future. InSAR is a sophisticated radar remote sensing technique for combining synthetic aperture radar (SAR single look complex images to form interferogram and utilizing its phase contribution to land topography, surface movement and target velocity. In recent years considerable applications of Interferometric SAR technique have been developed. It is an established technique for precise assessment of land surface movements, and generating high quality digital elevation models (DEM from space-borne and airborne data. InSAR is able to produce DEMs with the precision of a couple of ten meters whereas its movement map results have sub-centimeter precision. The technique has many applications in the context of earth sciences such as topographic mapping, environmental modelling, rainfall-runoff studies, landslide hazard zonation, and seismic source modelling. Nevertheless new developments are taking place in the application of InSAR for aquatic bodies. We have observed that using SAR Interferometry technique for aquatic bodies with the maximum temporal baseline of 16 seconds for image pairs shows considerable results enabling us to determine the direction of sea surface motion in a large area, estimate the sea surface fluctuations in the direction of sensor line-of-the-sight, detect wave pattern and the sea surface disturbance and whether the water motion is bulk and smooth or otherwise. This paper presents our experience and achievements on this new topic through discussing the facts and conditions for the use of InSAR technique. The method has been examined for Haiti, Dominican Republic, Western Chile and Western Turkey coast areas and inland lakes however ground truth data is needed for final verification. This technique scheduled to be applied in some other sites for which the proper data is available.

  10. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas

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    Zhenwei Chen

    2016-09-01

    Full Text Available Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level.

  11. An Improved InSAR Image Co-Registration Method for Pairs with Relatively Big Distortions or Large Incoherent Areas.

    Science.gov (United States)

    Chen, Zhenwei; Zhang, Lei; Zhang, Guo

    2016-09-17

    Co-registration is one of the most important steps in interferometric synthetic aperture radar (InSAR) data processing. The standard offset-measurement method based on cross-correlating uniformly distributed patches takes no account of specific geometric transformation between images or characteristics of ground scatterers. Hence, it is inefficient and difficult to obtain satisfying co-registration results for image pairs with relatively big distortion or large incoherent areas. Given this, an improved co-registration strategy is proposed in this paper which takes both the geometric features and image content into consideration. Firstly, some geometric transformations including scale, flip, rotation, and shear between images were eliminated based on the geometrical information, and the initial co-registration polynomial was obtained. Then the registration points were automatically detected by integrating the signal-to-clutter-ratio (SCR) thresholds and the amplitude information, and a further co-registration process was performed to refine the polynomial. Several comparison experiments were carried out using 2 TerraSAR-X data from the Hong Kong airport and 21 PALSAR data from the Donghai Bridge. Experiment results demonstrate that the proposed method brings accuracy and efficiency improvements for co-registration and processing abilities in the cases of big distortion between images or large incoherent areas in the images. For most co-registrations, the proposed method can enhance the reliability and applicability of co-registration and thus promote the automation to a higher level.

  12. Landslide precursory deformation interpretation using ALOS-2/PALSAR-2 InSAR image along Min River in Maoxien, Sichuan Province, China

    Science.gov (United States)

    Sato, H. P.

    2017-12-01

    Maoxien area in Sichuan Province, China has many landslide. For example, landslide (rock avalanche) occurred on the slope in Xinmocun Village in Maoxeien on 24 June 2017. I produced and interpreetd InSAR image using ALOS/PALSAR data observed on 19 Jul 2007-3 Sep 2007 and on 27 Jan 2011-14 Mar 2011, and ALOS-2/PALSAR-2 data observed on 26 Jul 2015-13 Dec 2015 and on 13 Dec 2015-11 Dec 2016. These images give good coherence and it was easy to identify local landslide surface deformation. As a result, e.g., two slopes were estimated to have local landslide surface deformation; one is at 103.936587 deg E and 32.04462 deg N, another is at 103.674754 deg E and 31.852838 N. However, the slope in Xinmocun Village was not identified as landslide precursory deformation. In the poster I will present more InSAR image observed after 11 Dec 2016 and discuss the possibility of local landslide surface deformaton using InSAR image. ALOS/PALSAR and ALOS-2/PALSAR-2 data were provided by JAXA through Landslide Working Group in JAXA and through Special Research 2015-B-02 of Earthquake Research Institute/Tokyo University. This study was supported by KAKENHI (17H02973).

  13. Large scale rock slope release planes imaged by differential ground based InSAR at Randa, Switzerland

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    Gischig, V.; Loew, S.; Kos, A.; Raetzo, H.

    2009-04-01

    In April and May of 1991 a steep rock slope above the village of Randa (Valais, Switzerland) failed in two events, releasing a total rock volume of 30 million m3. The rock mass behind the back scarp contains several million cubic meters of unstable gneisses and schists which are moving with a maximum rate of about 2 cm/yr. Different geodetic, geotechnical and geophysical techniques were applied to monitor this new instability and to determine its spatial extent. However, the boundaries of the instability could only be roughly estimated so far. For this reason five ground based differential InSAR surveys (GB-DInSAR) were carried out between 2005 and 2007 from the opposite valley flank at a distance to target of 1.3 to 1.9 km. These surveys provide displacements maps of four different time intervals with a spatial resolution of 2 to 6 m and an accuracy of less than 1 mm. These datasets reveal interesting new insights into the spatial distribution of displacements and significantly contribute to the kinematic interpretation of the ongoing movements. We found that the lower boundary of the instability is a narrow rupture plane which coincides with a primary lithological boundary on the slope. The intersection line between this basal rupture plane and the steep rock cliff extents over at least 200 m meters. It is possible to identify this structure on helicopter-based high resolution images and a LiDAR DTM of the failure surface. The eastern boundary of the instability also presents itself as a sharp line separating stable bedrock from a strongly fractured rock mass moving about 1 cm/yr along the line of sight. This lateral release plane is formed by a steeply east dipping tectonic fault plane, with subhorizontal striations and an exposed surface area of about 10'000 square meters. In the north-east of the instability the lateral boundaries crop out on surfaces that have an acute angle to the line of sight or lie in the shadow of the radar. Here the boundaries of the

  14. Measurement and imaging of infragravity waves in sea ice using InSAR

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    Mahoney, Andrew R.; Dammann, Dyre O.; Johnson, Mark A.; Eicken, Hajo; Meyer, Franz J.

    2016-06-01

    Using short-temporal baseline interferometric synthetic aperture radar, we capture instantaneous images of a persistent field of infragravity waves propagating through sea ice near Barrow, Alaska, during January 2015. We estimate wave amplitudes to be between 1.2 and 1.8 mm. Curvature of wavefronts is consistent with refraction of waves entering shallow water from a source region north of Barrow. A shallow water wave model indicates that the geometry of the wavefronts is relatively insensitive to the source location, but other evidence suggests the waves may have originated in the North Atlantic, making this perhaps the longest observed propagation path for waves through ice. We also note that steepening of the waves entering shallow water can increase the peak strain by an order of magnitude, suggesting that infragravity waves may play a role in determining the location of the landfast ice edge with respect to water depth.

  15. Seismic imaging beneath an InSAR anomaly in eastern Washington State: Shallow faulting associated with an earthquake swarm in a low-hazard area

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    Stephenson, William J.; Odum, Jackson K.; Wicks, Chuck; Pratt, Thomas L.; Blakely, Richard J.

    2016-01-01

    In 2001, a rare swarm of small, shallow earthquakes beneath the city of Spokane, Washington, caused ground shaking as well as audible booms over a five‐month period. Subsequent Interferometric Synthetic Aperture Radar (InSAR) data analysis revealed an area of surface uplift in the vicinity of the earthquake swarm. To investigate the potential faults that may have caused both the earthquakes and the topographic uplift, we collected ∼3  km of high‐resolution seismic‐reflection profiles to image the upper‐source region of the swarm. The two profiles reveal a complex deformational pattern within Quaternary alluvial, fluvial, and flood deposits, underlain by Tertiary basalts and basin sediments. At least 100 m of arching on a basalt surface in the upper 500 m is interpreted from both the seismic profiles and magnetic modeling. Two west‐dipping faults deform Quaternary sediments and project to the surface near the location of the Spokane fault defined from modeling of the InSAR data.

  16. Dynamic Optically Multiplexed Imaging

    Science.gov (United States)

    2015-07-29

    Dynamic Optically Multiplexed Imaging Yaron Rachlin, Vinay Shah, R. Hamilton Shepard, and Tina Shih Lincoln Laboratory, Massachusetts Institute of...V. Shah, and T. Shih “Design Architectures for Optically Multiplexed Imaging,” in submission 9 R. Gupta , P. Indyk, E. Price, and Y. Rachlin

  17. Imaging irregular magma reservoirs with InSAR and GPS observations: Application to Kilauea and Copahue volcanoes

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    Lundgren, P.; Camacho, A.; Poland, M. P.; Miklius, A.; Samsonov, S. V.; Milillo, P.

    2013-12-01

    The availability of synthetic aperture radar (SAR) interferometry (InSAR) data has increased our awareness of the complexity of volcano deformation sources. InSAR's spatial completeness helps identify or clarify source process mechanisms at volcanoes (i.e. Mt. Etna east flank motion; Lazufre crustal magma body; Kilauea dike complexity) and also improves potential model realism. In recent years, Bayesian inference methods have gained widespread use because of their ability to constrain not only source model parameters, but also their uncertainties. They are computationally intensive, however, which tends to limit them to a few geometrically rather simple source representations (for example, spheres). An alternative approach involves solving for irregular pressure and/or density sources from a three-dimensional (3-D) grid of source/density cells. This method has the ability to solve for arbitrarily shaped bodies of constant absolute pressure/density difference. We compare results for both Bayesian (a Markov chain Monte Carlo algorithm) and the irregular source methods for two volcanoes: Kilauea, Hawaii, and Copahue, Argentina-Chile border. Kilauea has extensive InSAR and GPS databases from which to explore the results for the irregular method with respect to the Bayesian approach, prior models, and an extensive set of ancillary data. One caveat, however, is the current restriction in the irregular model inversion to volume-pressure sources (and at a single excess pressure change), which limits its application in cases where sources such as faults or dikes are present. Preliminary results for Kilauea summit deflation during the March 2011 Kamoamoa eruption suggests a northeast-elongated magma body lying roughly 1-1.5 km below the surface. Copahue is a southern Andes volcano that has been inflating since early 2012, with intermittent summit eruptive activity since late 2012. We have an extensive InSAR time series from RADARSAT-2 and COSMO-SkyMed data, although both are

  18. Monitoring Building Deformation with InSAR: Experiments and Validation

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    Yang, Kui; Yan, Li; Huang, Guoman; Chen, Chu; Wu, Zhengpeng

    2016-01-01

    Synthetic Aperture Radar Interferometry (InSAR) techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS) regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE) indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated. PMID:27999403

  19. Monitoring Building Deformation with InSAR: Experiments and Validation

    Directory of Open Access Journals (Sweden)

    Kui Yang

    2016-12-01

    Full Text Available Synthetic Aperture Radar Interferometry (InSAR techniques are increasingly applied for monitoring land subsidence. The advantages of InSAR include high accuracy and the ability to cover large areas; nevertheless, research validating the use of InSAR on building deformation is limited. In this paper, we test the monitoring capability of the InSAR in experiments using two landmark buildings; the Bohai Building and the China Theater, located in Tianjin, China. They were selected as real examples to compare InSAR and leveling approaches for building deformation. Ten TerraSAR-X images spanning half a year were used in Permanent Scatterer InSAR processing. These extracted InSAR results were processed considering the diversity in both direction and spatial distribution, and were compared with true leveling values in both Ordinary Least Squares (OLS regression and measurement of error analyses. The detailed experimental results for the Bohai Building and the China Theater showed a high correlation between InSAR results and the leveling values. At the same time, the two Root Mean Square Error (RMSE indexes had values of approximately 1 mm. These analyses show that a millimeter level of accuracy can be achieved by means of InSAR technique when measuring building deformation. We discuss the differences in accuracy between OLS regression and measurement of error analyses, and compare the accuracy index of leveling in order to propose InSAR accuracy levels appropriate for monitoring buildings deformation. After assessing the advantages and limitations of InSAR techniques in monitoring buildings, further applications are evaluated.

  20. A Constellation of CubeSat InSAR Sensors for Rapid-Revisit Surface Deformation Studies

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    Wye, L.; Lee, S.; Yun, S. H.; Zebker, H. A.; Stock, J. D.; Wicks, C. W., Jr.; Doe, R.

    2016-12-01

    The 2007 NRC Decadal Survey for Earth Sciences highlights three major Earth surface deformation themes: 1) solid-earth hazards and dynamics; 2) human health and security; and 3) land-use change, ecosystem dynamics and biodiversity. Space-based interferometric synthetic aperture radar (InSAR) is a key change detection tool for addressing these themes. Here, we describe the mission and radar payload design for a constellation of S-band InSAR sensors specifically designed to provide the global, high temporal resolution, sub-cm level deformation accuracy needed to address some of the major Earth system goals. InSAR observations with high temporal resolution are needed to properly monitor certain nonlinearly time-varying features (e.g., unstable volcanoes, active fault lines, and heavily-used groundwater or hydrocarbon reservoirs). Good temporal coverage is also needed to reduce atmospheric artifacts by allowing multiple acquisitions to be averaged together, since each individual SAR measurement is corrupted by up to several cm of atmospheric noise. A single InSAR platform is limited in how often it can observe a given scene without sacrificing global spatial coverage. Multiple InSAR platforms provide the spatial-temporal flexibility required to maximize the science return. However, building and launching multiple InSAR platforms is cost-prohibitive for traditional satellites. SRI International (SRI) and our collaborators are working to exploit developments in nanosatellite technology, in particular the emergence of the CubeSat standard, to provide high-cadence InSAR capabilities in an affordable package. The CubeSat Imaging Radar for Earth Science (CIRES) subsystem, a prototype SAR elec­tronics package developed by SRI with support from a 2014 NASA ESTO ACT award, is specifically scaled to be a drop-in radar solution for resource-limited delivery systems like CubeSats and small airborne vehicles. Here, we present our mission concept and flow-down requirements for a

  1. Characterizing and estimating noise in InSAR and InSAR time series with MODIS

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    Barnhart, William D.; Lohman, Rowena B.

    2013-01-01

    InSAR time series analysis is increasingly used to image subcentimeter displacement rates of the ground surface. The precision of InSAR observations is often affected by several noise sources, including spatially correlated noise from the turbulent atmosphere. Under ideal scenarios, InSAR time series techniques can substantially mitigate these effects; however, in practice the temporal distribution of InSAR acquisitions over much of the world exhibit seasonal biases, long temporal gaps, and insufficient acquisitions to confidently obtain the precisions desired for tectonic research. Here, we introduce a technique for constraining the magnitude of errors expected from atmospheric phase delays on the ground displacement rates inferred from an InSAR time series using independent observations of precipitable water vapor from MODIS. We implement a Monte Carlo error estimation technique based on multiple (100+) MODIS-based time series that sample date ranges close to the acquisitions times of the available SAR imagery. This stochastic approach allows evaluation of the significance of signals present in the final time series product, in particular their correlation with topography and seasonality. We find that topographically correlated noise in individual interferograms is not spatially stationary, even over short-spatial scales (<10 km). Overall, MODIS-inferred displacements and velocities exhibit errors of similar magnitude to the variability within an InSAR time series. We examine the MODIS-based confidence bounds in regions with a range of inferred displacement rates, and find we are capable of resolving velocities as low as 1.5 mm/yr with uncertainties increasing to ∼6 mm/yr in regions with higher topographic relief.

  2. FEM-based linear inverse modeling using a 3D source array to image magma chambers with free geometry. Application to InSAR data from Rabaul Caldera (PNG).

    Science.gov (United States)

    Ronchin, Erika; Masterlark, Timothy; Dawson, John; Saunders, Steve; Martí Molist, Joan

    2015-04-01

    spatial distribution of sources find correspondence in the petrography of the volcanic products described in literature and in the dynamics of the single and twin eruptions that characterize the caldera. As many other volcanoes, Rabaul caldera is an active and dangerous volcanic system whose dynamics still need to be understood to effectively predict the behavior of future eruptions. The good results obtained from the application of the method to Rabaul caldera show that the proposed linear inversion based on the FEM array of sources is suitable to generate models of magmatic systems. The method can image in space and time the complex free geometry of the source that generates the deformation, widening our understanding of deformational sources and their dynamics. This takes source modeling a step towards more realistic source models.

  3. Detecting and monitoring UCG subsidence with InSAR

    Energy Technology Data Exchange (ETDEWEB)

    Mellors, R J; Foxall, W; Yang, X

    2012-03-23

    The use of interferometric synthetic aperture radar (InSAR) to measure surface subsidence caused by Underground Coal Gasification (UCG) is tested. InSAR is a remote sensing technique that uses Synthetic Aperture Radar images to make spatial images of surface deformation and may be deployed from satellite or an airplane. With current commercial satellite data, the technique works best in areas with little vegetation or farming activity. UCG subsidence is generally caused by roof collapse, which adversely affects UCG operations due to gas loss and is therefore important to monitor. Previous studies have demonstrated the usefulness of InSAR in measuring surface subsidence related to coal mining and surface deformation caused by a coal mining roof collapse in Crandall Canyon, Utah is imaged as a proof-of-concept. InSAR data is collected and processed over three known UCG operations including two pilot plants (Majuba, South Africa and Wulanchabu, China) and an operational plant (Angren, Uzbekistan). A clear f eature showing approximately 7 cm of subsidence is observed in the UCG field in Angren. Subsidence is not observed in the other two areas, which produce from deeper coal seams and processed a smaller volume. The results show that in some cases, InSAR is a useful tool to image UCG related subsidence. Data from newer satellites and improved algorithms will improve effectiveness.

  4. InSAR deformation monitoring of high risk landslides

    Science.gov (United States)

    Singhroy, V.; Li, J.

    2013-05-01

    During the past year there were at least twenty five media reports of landslides and seismic activities some fatal, occurring in various areas in Canada. These high risk geohazards sites requires high resolution monitoring both spatially and temporally for mitigation purposes, since they are near populated areas and energy, transportation and communication corridors. High resolution air photos, lidar and satellite images are quite common in areas where the landslides can be fatal. Radar interferometry (InSAR) techniques using images from several radar satellites are increasingly being used in slope stability assessment. This presentation provides examples of using high-resolution (1-3m) frequent revisits InSAR techniques from RADARSAT 2 and TerraSAR X to monitor several types of high-risk landslides affecting transportation and energy corridors and populated areas. We have analyses over 200 high resolution InSAR images over a three year period on geologically different landslides. The high-resolution InSAR images are effective in characterizing differential motion within these low velocity landslides. The low velocity landslides become high risk during the active wet spring periods. The wet soils are poor coherent targets and corner reflectors provide an effective means of InSAR monitoring the slope activities.

  5. Musashi dynamic image processing system

    International Nuclear Information System (INIS)

    Murata, Yutaka; Mochiki, Koh-ichi; Taguchi, Akira

    1992-01-01

    In order to produce transmitted neutron dynamic images using neutron radiography, a real time system called Musashi dynamic image processing system (MDIPS) was developed to collect, process, display and record image data. The block diagram of the MDIPS is shown. The system consists of a highly sensitive, high resolution TV camera driven by a custom-made scanner, a TV camera deflection controller for optimal scanning, which adjusts to the luminous intensity and the moving speed of an object, a real-time corrector to perform the real time correction of dark current, shading distortion and field intensity fluctuation, a real time filter for increasing the image signal to noise ratio, a video recording unit and a pseudocolor monitor to realize recording in commercially available products and monitoring by means of the CRTs in standard TV scanning, respectively. The TV camera and the TV camera deflection controller utilized for producing still images can be applied to this case. The block diagram of the real-time corrector is shown. Its performance is explained. Linear filters and ranked order filters were developed. (K.I.)

  6. InSAR observations of active volcanoes in Latin America

    Science.gov (United States)

    Morales Rivera, A. M.; Chaussard, E.; Amelung, F.

    2012-12-01

    Over the last decade satellite-based interferometric synthetic aperture radar (InSAR) has developed into a well-known technique to gauge the status of active volcanoes. The InSAR technique can detect the ascent of magma to shallow levels of the volcanic plumbing system because new arriving magma pressurizes the system. This is likely associated with the inflation of the volcanic edifice and the surroundings. Although the potential of InSAR to detect magma migration is well known, the principal limitation was that only for few volcanoes frequent observations were acquired. The ALOS-1 satellite of the Japanese Aerospace Exploration Agency (JAXA) acquired a global L-band data set of 15-20 acquisitions during 2006-2011. Here we use ALOS InSAR and Small Baseline (SB) time-series methods for a ground deformation survey of Latin America with emphasis on the northern Andes. We present time-dependent ground deformation data for the volcanoes in Colombia, Ecuador and Peru and interpret the observations in terms of the dynamics of the volcanic systems.

  7. Geocoronal imaging with Dynamics Explorer

    Science.gov (United States)

    Rairden, R. L.; Frank, L. A.; Craven, J. D.

    1986-01-01

    The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer.

  8. Long-term ground deformation patterns of Bucharest using multi-temporal InSAR and multivariate dynamic analyses: a possible transpressional system?

    Science.gov (United States)

    Armaş, Iuliana; Mendes, Diana A.; Popa, Răzvan-Gabriel; Gheorghe, Mihaela; Popovici, Diana

    2017-03-01

    The aim of this exploratory research is to capture spatial evolution patterns in the Bucharest metropolitan area using sets of single polarised synthetic aperture radar (SAR) satellite data and multi-temporal radar interferometry. Three sets of SAR data acquired during the years 1992-2010 from ERS-1/-2 and ENVISAT, and 2011-2014 from TerraSAR-X satellites were used in conjunction with the Small Baseline Subset (SBAS) and persistent scatterers (PS) high-resolution multi-temporal interferometry (InSAR) techniques to provide maps of line-of-sight displacements. The satellite-based remote sensing results were combined with results derived from classical methodologies (i.e., diachronic cartography) and field research to study possible trends in developments over former clay pits, landfill excavation sites, and industrial parks. The ground displacement trend patterns were analysed using several linear and nonlinear models, and techniques. Trends based on the estimated ground displacement are characterised by long-term memory, indicated by low noise Hurst exponents, which in the long-term form interesting attractors. We hypothesize these attractors to be tectonic stress fields generated by transpressional movements.

  9. Quantitative assessment of dynamic PET imaging data in cancer imaging.

    Science.gov (United States)

    Muzi, Mark; O'Sullivan, Finbarr; Mankoff, David A; Doot, Robert K; Pierce, Larry A; Kurland, Brenda F; Linden, Hannah M; Kinahan, Paul E

    2012-11-01

    Clinical imaging in positron emission tomography (PET) is often performed using single-time-point estimates of tracer uptake or static imaging that provides a spatial map of regional tracer concentration. However, dynamic tracer imaging can provide considerably more information about in vivo biology by delineating both the temporal and spatial pattern of tracer uptake. In addition, several potential sources of error that occur in static imaging can be mitigated. This review focuses on the application of dynamic PET imaging to measuring regional cancer biologic features and especially in using dynamic PET imaging for quantitative therapeutic response monitoring for cancer clinical trials. Dynamic PET imaging output parameters, particularly transport (flow) and overall metabolic rate, have provided imaging end points for clinical trials at single-center institutions for years. However, dynamic imaging poses many challenges for multicenter clinical trial implementations from cross-center calibration to the inadequacy of a common informatics infrastructure. Underlying principles and methodology of PET dynamic imaging are first reviewed, followed by an examination of current approaches to dynamic PET image analysis with a specific case example of dynamic fluorothymidine imaging to illustrate the approach. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. High dynamic range coding imaging system

    Science.gov (United States)

    Wu, Renfan; Huang, Yifan; Hou, Guangqi

    2014-10-01

    We present a high dynamic range (HDR) imaging system design scheme based on coded aperture technique. This scheme can help us obtain HDR images which have extended depth of field. We adopt Sparse coding algorithm to design coded patterns. Then we utilize the sensor unit to acquire coded images under different exposure settings. With the guide of the multiple exposure parameters, a series of low dynamic range (LDR) coded images are reconstructed. We use some existing algorithms to fuse and display a HDR image by those LDR images. We build an optical simulation model and get some simulation images to verify the novel system.

  11. Dynamic CT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Caruso, Damiano; Eid, Marwen; Schoepf, U. Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie

    2016-01-01

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  12. Dynamic CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncological and Pathological Sciences, University of Rome “Sapienza”, Latina (Italy); Eid, Marwen [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Mangold, Stefanie [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen (Germany); and others

    2016-10-15

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  13. Comparison of four moderate-size earthquakes in southern California using seismology and InSAR

    Science.gov (United States)

    Mellors, R.J.; Magistrale, H.; Earle, P.; Cogbill, A.H.

    2004-01-01

    Source parameters determined from interferometric synthetic aperture radar (InSAR) measurements and from seismic data are compared from four moderate-size (less than M 6) earthquakes in southern California. The goal is to verify approximate detection capabilities of InSAR, assess differences in the results, and test how the two results can be reconciled. First, we calculated the expected surface deformation from all earthquakes greater than magnitude 4 in areas with available InSAR data (347 events). A search for deformation from the events in the interferograms yielded four possible events with magnitudes less than 6. The search for deformation was based on a visual inspection as well as cross-correlation in two dimensions between the measured signal and the expected signal. A grid-search algorithm was then used to estimate focal mechanism and depth from the InSAR data. The results were compared with locations and focal mechanisms from published catalogs. An independent relocation using seismic data was also performed. The seismic locations fell within the area of the expected rupture zone for the three events that show clear surface deformation. Therefore, the technique shows the capability to resolve locations with high accuracy and is applicable worldwide. The depths determined by InSAR agree with well-constrained seismic locations determined in a 3D velocity model. Depth control for well-imaged shallow events using InSAR data is good, and better than the seismic constraints in some cases. A major difficulty for InSAR analysis is the poor temporal coverage of InSAR data, which may make it impossible to distinguish deformation due to different earthquakes at the same location.

  14. Semi-physical Simulation of the Airborne InSAR based on Rigorous Geometric Model and Real Navigation Data

    Science.gov (United States)

    Changyong, Dou; Huadong, Guo; Chunming, Han; yuquan, Liu; Xijuan, Yue; Yinghui, Zhao

    2014-03-01

    Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc.

  15. Semi-physical Simulation of the Airborne InSAR based on Rigorous Geometric Model and Real Navigation Data

    International Nuclear Information System (INIS)

    Changyong, Dou; Huadong, Guo; Chunming, Han; Yuquan, Liu; Xijuan, Yue; Yinghui, Zhao

    2014-01-01

    Raw signal simulation is a useful tool for the system design, mission planning, processing algorithm testing, and inversion algorithm design of Synthetic Aperture Radar (SAR). Due to the wide and high frequent variation of aircraft's trajectory and attitude, and the low accuracy of the Position and Orientation System (POS)'s recording data, it's difficult to quantitatively study the sensitivity of the key parameters, i.e., the baseline length and inclination, absolute phase and the orientation of the antennas etc., of the airborne Interferometric SAR (InSAR) system, resulting in challenges for its applications. Furthermore, the imprecise estimation of the installation offset between the Global Positioning System (GPS), Inertial Measurement Unit (IMU) and the InSAR antennas compounds the issue. An airborne interferometric SAR (InSAR) simulation based on the rigorous geometric model and real navigation data is proposed in this paper, providing a way for quantitatively studying the key parameters and for evaluating the effect from the parameters on the applications of airborne InSAR, as photogrammetric mapping, high-resolution Digital Elevation Model (DEM) generation, and surface deformation by Differential InSAR technology, etc. The simulation can also provide reference for the optimal design of the InSAR system and the improvement of InSAR data processing technologies such as motion compensation, imaging, image co-registration, and application parameter retrieval, etc

  16. Dynamic MR imaging of pancreatic cancer

    International Nuclear Information System (INIS)

    Akaki, Shiro; Kohno, Yoshihiro; Gohbara, Hideo

    1994-01-01

    Dynamic MRI was performed on 21 patients with pancreatic duct cell carcinoma. Turbo-FLASH or FLASH3D was performed immediately following rapid bolus injection of gadopentetate dimeglumine, and these FLASH images and conventional spin echo images were evaluated about detectability of the lesion. All images were classified into three groups of detectability of the lesion ; good, fair, and poor. On T 1 weighted image, 23% of cases were 'good' and 48% were evaluated as 'fair'. On the other hand, on dynamic MRI, 62% of cases were 'good' and 33% of cases were evaluated as 'fair'. Both T 2 weighted image and enhanced T 1 weighted image were not useful for depiction of the lesion. Direct comparison between T 1 weighted image and dynamic MRI was also done. In 55% of cases, dynamic MRI was superior to T 1 weighted image and in 40% of cases, dynamic MRI was equal to T 1 weighted image. Thus, dynamic MRI was superior to conventional spin echo images for detection of duct cell carcinoma. In 17 patients of duct cell carcinoma who underwent FLASH3D, contrast/noise ratio (CNR) was calculated before and after injection of gadopentetate dimeglumine. The absolute value of CNR became significantly larger by injection of contrast material. In nine resectable pancreatic carcinomas, two cases of INF α and two cases of medullary type were well depicted. It was concluded that dynamic MRI was useful for evaluation of pancreatic carcinoma. (author)

  17. Dynamic MR imaging in the musculoskeletal system

    International Nuclear Information System (INIS)

    Hedlund, L.; Vogler, J.; Utz, J.A.; Herfkens, R.J.; Martinez, S.; Urbaniak, J.; Evans, A.

    1986-01-01

    Many joint disorders are related to movement, and lack of dynamic imaging has thus far been a limitation of MR imaging. A recently developed dynamic MR imaging technique utilizing a gradient refocused echo (TE = 12 msec, TR = 21 msec) coupled to a physiologic trigger allows dynamic images of the moving joint to be obtained. Controlled joint articulation is produced using an air-driven nonmagnetic device. Imaging of the wrist by this technique demonstrated the dynamic motion of the carpal rows. The method displays cartilage with more sensitivity than does conventional MR imaging; thus, ligamentous and triangular cartilage alignment could be evaluated during motion. In the wrist, potential applications include imaging of carpal instability syndromes, ligamentous interruption, and tears of the triangular cartilage

  18. Basic to Advanced InSAR Processing: GMTSAR

    Science.gov (United States)

    Sandwell, D. T.; Xu, X.; Baker, S.; Hogrelius, A.; Mellors, R. J.; Tong, X.; Wei, M.; Wessel, P.

    2017-12-01

    Monitoring crustal deformation using InSAR is becoming a standard technique for the science and application communities. Optimal use of the new data streams from Sentinel-1 and NISAR will require open software tools as well as education on the strengths and limitations of the InSAR methods. Over the past decade we have developed freely available, open-source software for processing InSAR data. The software relies on the Generic Mapping Tools (GMT) for the back-end data analysis and display and is thus called GMTSAR. With startup funding from NSF, we accelerated the development of GMTSAR to include more satellite data sources and provide better integration and distribution with GMT. In addition, with support from UNAVCO we have offered 6 GMTSAR short courses to educate mostly novice InSAR users. Currently, the software is used by hundreds of scientists and engineers around the world to study deformation at more than 4300 different sites. The most challenging aspect of the recent software development was the transition from image alignment using the cross-correlation method to a completely new alignment algorithm that uses only the precise orbital information to geometrically align images to an accuracy of better than 7 cm. This development was needed to process a new data type that is being acquired by the Sentinel-1A/B satellites. This combination of software and open data is transforming radar interferometry from a research tool into a fully operational time series analysis tool. Over the next 5 years we are planning to continue to broaden the user base through: improved software delivery methods; code hardening; better integration with data archives; support for high level products being developed for NISAR; and continued education and outreach.

  19. Dynamic MR imaging of the musculoskeletal system

    International Nuclear Information System (INIS)

    Shah, A.S.; Hylton, H.; Hentz, V.R.; Schattner, P.

    1991-01-01

    This paper reports on dynamic MR imaging which is an MR technique that allows imaging of the musculoskeletal system in motion. Current methods for observing the articulation of muscles and joints are limited to acquisition of stationary images at different spatial orientations. These images are then replayed from computer memory to simulate motion. Unlike stationary acquisition, dynamic MR imaging allows the volume of interest to be subjected to motion and dynamic stress, which is important for detecting stress-induced pathology. To demonstrate the utility of dynamic MR imaging, a system for imaging a moving wrist has been developed. The system consists of apparatus capable of providing simultaneous radialulnar deviation and flexion-extension, and hardware for system control and acquisition gating. The apparatus is mounted on the patient bed and is transferable to a variety of standard clinical MR imaging systems. Images were obtained during motion, and the ability of dynamic MR imaging to accurately image the moving wrist with very little motion artifact was demonstrated

  20. Image reconstruction of dynamic infrared single-pixel imaging system

    Science.gov (United States)

    Tong, Qi; Jiang, Yilin; Wang, Haiyan; Guo, Limin

    2018-03-01

    Single-pixel imaging technique has recently received much attention. Most of the current single-pixel imaging is aimed at relatively static targets or the imaging system is fixed, which is limited by the number of measurements received through the single detector. In this paper, we proposed a novel dynamic compressive imaging method to solve the imaging problem, where exists imaging system motion behavior, for the infrared (IR) rosette scanning system. The relationship between adjacent target images and scene is analyzed under different system movement scenarios. These relationships are used to build dynamic compressive imaging models. Simulation results demonstrate that the proposed method can improve the reconstruction quality of IR image and enhance the contrast between the target and the background in the presence of system movement.

  1. Dynamic MR imaging of pituitary adenoma

    International Nuclear Information System (INIS)

    Miki, Yukio; Nishizawa, Sadahiko; Kuroda, Yasumasa; Keyaki, Atsushi; Nabeshima, Sachio; Kawamura, Junichiro; Matsuo, Michimasa

    1990-01-01

    The authors performed serial dynamic MR imaging in patients with 10 normal pituitary and 21 pituitary adenoma utilizing spin-echo sequence with a very short repetition time (SE 100/15) every minute immediately after a bolus injection of Gd-DTPA. Usual T 1 -weighted images (SE 600/15) were also obtained before and after the dynamic study. Pituitary adenomas included 10 adenomas confirmed by surgery, 4 adenomas confirmed by biologic data, and 7 postoperative adenomas. Out of 10 patients who underwent surgery after dynamic MRI, 9 patients underwent postoperative dynamic MRI. In normal patients, the pituitary gland was markedly enhanced on the early-phase images of the dynamic study, followed by gradual decrease of intensity throughout the dynamic study. In cases of microadenomas, the contrast between the normal pituitary gland and adenoma is better than that on the usual T 1 -weighted images by marked enhancement of the normal pituitary gland. Dynamic images clearly showed the residual normal pituitary glands in all cases of macroadenoma larger than 15 mm in diameter, whereas usual contrast-enhanced images showed the normal pituitary gland only in one case. In all patients who underwent both preoperative and postoperative dynamic MRI, postoperative dynamic MRI showed the normal pituitary glands which are markedly enhanced on the early-phase images in the sites which correspond to the preoperative dynamic study. The normal residual anterior gland was also visualized in four out of 7 patients who received only postoperative dynamic MRI. Dynamic MRI is a strong diagnostic modality for visualizing microadenoma and for visualizing the normal pituitary gland in cases of preoperative and postoperative macroadenoma. (author)

  2. Combined DEM Extration Method from StereoSAR and InSAR

    Science.gov (United States)

    Zhao, Z.; Zhang, J. X.; Duan, M. Y.; Huang, G. M.; Yang, S. C.

    2015-06-01

    A pair of SAR images acquired from different positions can be used to generate digital elevation model (DEM). Two techniques exploiting this characteristic have been introduced: stereo SAR and interferometric SAR. They permit to recover the third dimension (topography) and, at the same time, to identify the absolute position (geolocation) of pixels included in the imaged area, thus allowing the generation of DEMs. In this paper, StereoSAR and InSAR combined adjustment model are constructed, and unify DEM extraction from InSAR and StereoSAR into the same coordinate system, and then improve three dimensional positioning accuracy of the target. We assume that there are four images 1, 2, 3 and 4. One pair of SAR images 1,2 meet the required conditions for InSAR technology, while the other pair of SAR images 3,4 can form stereo image pairs. The phase model is based on InSAR rigorous imaging geometric model. The master image 1 and the slave image 2 will be used in InSAR processing, but the slave image 2 is only used in the course of establishment, and the pixels of the slave image 2 are relevant to the corresponding pixels of the master image 1 through image coregistration coefficient, and it calculates the corresponding phase. It doesn't require the slave image in the construction of the phase model. In Range-Doppler (RD) model, the range equation and Doppler equation are a function of target geolocation, while in the phase equation, the phase is also a function of target geolocation. We exploit combined adjustment model to deviation of target geolocation, thus the problem of target solution is changed to solve three unkonwns through seven equations. The model was tested for DEM extraction under spaceborne InSAR and StereoSAR data and compared with InSAR and StereoSAR methods respectively. The results showed that the model delivered a better performance on experimental imagery and can be used for DEM extraction applications.

  3. Magnetic Resonance Imaging (MRI): Dynamic Pelvic Floor

    Science.gov (United States)

    ... to a CD or uploaded to a digital cloud server. Dynamic pelvic floor MRI provides detailed pictures ... with you. top of page What are the benefits vs. risks? Benefits MRI is a noninvasive imaging ...

  4. High Dynamic Range Imaging Using Multiple Exposures

    Science.gov (United States)

    Hou, Xinglin; Luo, Haibo; Zhou, Peipei; Zhou, Wei

    2017-06-01

    It is challenging to capture a high-dynamic range (HDR) scene using a low-dynamic range (LDR) camera. This paper presents an approach for improving the dynamic range of cameras by using multiple exposure images of same scene taken under different exposure times. First, the camera response function (CRF) is recovered by solving a high-order polynomial in which only the ratios of the exposures are used. Then, the HDR radiance image is reconstructed by weighted summation of the each radiance maps. After that, a novel local tone mapping (TM) operator is proposed for the display of the HDR radiance image. By solving the high-order polynomial, the CRF can be recovered quickly and easily. Taken the local image feature and characteristic of histogram statics into consideration, the proposed TM operator could preserve the local details efficiently. Experimental result demonstrates the effectiveness of our method. By comparison, the method outperforms other methods in terms of imaging quality.

  5. InSAR Scientific Computing Environment

    Science.gov (United States)

    Rosen, Paul A.; Sacco, Gian Franco; Gurrola, Eric M.; Zabker, Howard A.

    2011-01-01

    This computing environment is the next generation of geodetic image processing technology for repeat-pass Interferometric Synthetic Aperture (InSAR) sensors, identified by the community as a needed capability to provide flexibility and extensibility in reducing measurements from radar satellites and aircraft to new geophysical products. This software allows users of interferometric radar data the flexibility to process from Level 0 to Level 4 products using a variety of algorithms and for a range of available sensors. There are many radar satellites in orbit today delivering to the science community data of unprecedented quantity and quality, making possible large-scale studies in climate research, natural hazards, and the Earth's ecosystem. The proposed DESDynI mission, now under consideration by NASA for launch later in this decade, would provide time series and multiimage measurements that permit 4D models of Earth surface processes so that, for example, climate-induced changes over time would become apparent and quantifiable. This advanced data processing technology, applied to a global data set such as from the proposed DESDynI mission, enables a new class of analyses at time and spatial scales unavailable using current approaches. This software implements an accurate, extensible, and modular processing system designed to realize the full potential of InSAR data from future missions such as the proposed DESDynI, existing radar satellite data, as well as data from the NASA UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar), and other airborne platforms. The processing approach has been re-thought in order to enable multi-scene analysis by adding new algorithms and data interfaces, to permit user-reconfigurable operation and extensibility, and to capitalize on codes already developed by NASA and the science community. The framework incorporates modern programming methods based on recent research, including object-oriented scripts controlling legacy and

  6. Using InSAR to Observe Sinkhole Activity in Central Florida

    Science.gov (United States)

    Oliver-Cabrera, T.; Wdowinski, S.; Kruse, S.; Kiflu, H. G.

    2017-12-01

    Sinkhole collapse in Florida is a major geologic hazard, threatening human life and causing substantial damage to property. Detecting sinkhole deformation before a collapse is an important but difficult task; most techniques used to monitor sinkholes are spatially constrained to relatively small areas (tens to hundred meters). To overcome this limitation, we use Interferometric Synthetic Aperture Radar (InSAR), which is a very useful technique for detecting localized deformation while covering vast areas. InSAR results show localized deformation at several houses and commercial buildings in different locations along the study sites. We use a subsurface imaging technique, ground penetrating radar, to verify sinkhole existence beneath the observed deforming areas.

  7. Helmand river hydrologic studies using ALOS PALSAR InSAR and ENVISAT altimetry

    Science.gov (United States)

    Lu, Zhong; Kim, J.-W.; Lee, H.; Shum, C.K.; Duan, J.; Ibaraki, M.; Akyilmaz, O.; Read, C.-H.

    2009-01-01

    The Helmand River wetland represents the only fresh-water resource in southern Afghanistan and one of the least mapped water basins in the world. The relatively narrow wetland consists of mostly marshes surrounded by dry lands. In this study, we demonstrate the use of the Advanced Land Observing Satellite (ALOS) Phased Array type L-band Synthetic Aperture Radar (PALSAR) Interferometric SAR (InSAR) to detect the changes of the Helmand River wetland water level. InSAR images are combined with the geocentric water level measurements from the retracked high-rate (18-Hz) Environmental Satellite (Envisat) radar altimetry to construct absolute water level changes over the marshes. It is demonstrated that the integration of the altimeter and InSAR can provide spatio-temporal measurements of water level variation over the Helmand River marshes where in situ measurements are absent. ?? Taylor & Francis Group, LLC.

  8. Dynamic imaging of oropharyngeal swallowing

    International Nuclear Information System (INIS)

    Fanucci, A.; Cerro, P.; Diotallevi, P.; Metastasio, F.; Fanucci, E.

    1991-01-01

    Oropharyngeal swallowing is too fast and complex a motion for the human eye to seize its various phases and subsequently evaluate morphology and function of the anatomical structures involved. A chronological subdivision of the swallowing act is needed for e step-by-step analysis. Dinamic evaluation of oropharyngeal swallowing by means of fluoroscopic and US videorecording proved to be a reliable method. Echovideorecording allowed tongue movements to be depicted, together with bolus formation and propulsion. Fluorovideorecording (U-Matic Sony unit, 25-30 images/sec) demonstrated pharyngeal and esophageal phases. A series of chronological and morphological reference points, which characterize oropharyngeal swallowing, were employed to analyze videorecorded images. Slowmotion mode, 'freezed' images, and rewinding allowed an easy and accurate evaluation of swallowing details. Combined chronological and morphological pieces of information allow a comprehensive evaluation of the swallowing act

  9. Analysis of the Effect of Radio Frequency Interference on Repeat Track Airborne InSAR System

    Directory of Open Access Journals (Sweden)

    Ding Bin

    2012-03-01

    Full Text Available The SAR system operating at low frequency is susceptible to Radio Frequency Interference (RFI from television station, radio station, and some other civil electronic facilities. The presence of RFI degrades the SAR image quality, and obscures the targets in the scene. Furthermore, RFI can cause interferometric phase error in repeat track InSAR system. In order to analyze the effect of RFI on interferometric phase of InSAR, real measured RFI signal are added on cone simulated SAR echoes. The imaging and interferometric processing results of both the RFI-contaminated and raw data are given. The effect of real measured RFI signal on repeat track InSAR system is analyzed. Finally, the imaging and interferometric processing results of both with and without RFI suppressed of the P band airborne repeat track InSAR real data are presented, which demonstrates the efficiency of the RFI suppression method in terms of decreasing the interferometric phase errors caused by RFI.

  10. Understanding synthesis imaging dynamic range

    Science.gov (United States)

    Braun, R.

    2013-03-01

    We develop a general framework for quantifying the many different contributions to the noise budget of an image made with an array of dishes or aperture array stations. Each noise contribution to the visibility data is associated with a relevant correlation timescale and frequency bandwidth so that the net impact on a complete observation can be assessed when a particular effect is not captured in the instrumental calibration. All quantities are parameterised as function of observing frequency and the visibility baseline length. We apply the resulting noise budget analysis to a wide range of existing and planned telescope systems that will operate between about 100 MHz and 5 GHz to ascertain the magnitude of the calibration challenges that they must overcome to achieve thermal noise limited performance. We conclude that calibration challenges are increased in several respects by small dimensions of the dishes or aperture array stations. It will be more challenging to achieve thermal noise limited performance using 15 m class dishes rather than the 25 m dishes of current arrays. Some of the performance risks are mitigated by the deployment of phased array feeds and more with the choice of an (alt,az,pol) mount, although a larger dish diameter offers the best prospects for risk mitigation. Many improvements to imaging performance can be anticipated at the expense of greater complexity in calibration algorithms. However, a fundamental limitation is ultimately imposed by an insufficient number of data constraints relative to calibration variables. The upcoming aperture array systems will be operating in a regime that has never previously been addressed, where a wide range of effects are expected to exceed the thermal noise by two to three orders of magnitude. Achieving routine thermal noise limited imaging performance with these systems presents an extreme challenge. The magnitude of that challenge is inversely related to the aperture array station diameter.

  11. Quantum dynamic imaging theoretical and numerical methods

    CERN Document Server

    Ivanov, Misha

    2011-01-01

    Studying and using light or "photons" to image and then to control and transmit molecular information is among the most challenging and significant research fields to emerge in recent years. One of the fastest growing areas involves research in the temporal imaging of quantum phenomena, ranging from molecular dynamics in the femto (10-15s) time regime for atomic motion to the atto (10-18s) time scale of electron motion. In fact, the attosecond "revolution" is now recognized as one of the most important recent breakthroughs and innovations in the science of the 21st century. A major participant in the development of ultrafast femto and attosecond temporal imaging of molecular quantum phenomena has been theory and numerical simulation of the nonlinear, non-perturbative response of atoms and molecules to ultrashort laser pulses. Therefore, imaging quantum dynamics is a new frontier of science requiring advanced mathematical approaches for analyzing and solving spatial and temporal multidimensional partial differ...

  12. Calibration of a Land Subsidence Model Using InSAR Data via the Ensemble Kalman Filter.

    Science.gov (United States)

    Li, Liangping; Zhang, Meijing; Katzenstein, Kurt

    2017-11-01

    The application of interferometric synthetic aperture radar (InSAR) has been increasingly used to improve capabilities to model land subsidence in hydrogeologic studies. A number of investigations over the last decade show how spatially detailed time-lapse images of ground displacements could be utilized to advance our understanding for better predictions. In this work, we use simulated land subsidences as observed measurements, mimicking InSAR data to inversely infer inelastic specific storage in a stochastic framework. The inelastic specific storage is assumed as a random variable and modeled using a geostatistical method such that the detailed variations in space could be represented and also that the uncertainties of both characterization of specific storage and prediction of land subsidence can be assessed. The ensemble Kalman filter (EnKF), a real-time data assimilation algorithm, is used to inversely calibrate a land subsidence model by matching simulated subsidences with InSAR data. The performance of the EnKF is demonstrated in a synthetic example in which simulated surface deformations using a reference field are assumed as InSAR data for inverse modeling. The results indicate: (1) the EnKF can be used successfully to calibrate a land subsidence model with InSAR data; the estimation of inelastic specific storage is improved, and uncertainty of prediction is reduced, when all the data are accounted for; and (2) if the same ensemble is used to estimate Kalman gain, the analysis errors could cause filter divergence; thus, it is essential to include localization in the EnKF for InSAR data assimilation. © 2017, National Ground Water Association.

  13. Dynamic metamaterial aperture for microwave imaging

    International Nuclear Information System (INIS)

    Sleasman, Timothy; Imani, Mohammadreza F.; Gollub, Jonah N.; Smith, David R.

    2015-01-01

    We present a dynamic metamaterial aperture for use in computational imaging schemes at microwave frequencies. The aperture consists of an array of complementary, resonant metamaterial elements patterned into the upper conductor of a microstrip line. Each metamaterial element contains two diodes connected to an external control circuit such that the resonance of the metamaterial element can be damped by application of a bias voltage. Through applying different voltages to the control circuit, select subsets of the elements can be switched on to create unique radiation patterns that illuminate the scene. Spatial information of an imaging domain can thus be encoded onto this set of radiation patterns, or measurements, which can be processed to reconstruct the targets in the scene using compressive sensing algorithms. We discuss the design and operation of a metamaterial imaging system and demonstrate reconstructed images with a 10:1 compression ratio. Dynamic metamaterial apertures can potentially be of benefit in microwave or millimeter wave systems such as those used in security screening and through-wall imaging. In addition, feature-specific or adaptive imaging can be facilitated through the use of the dynamic aperture

  14. Dynamic metamaterial aperture for microwave imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sleasman, Timothy; Imani, Mohammadreza F.; Gollub, Jonah N.; Smith, David R. [Center for Metamaterials and Integrated Plasmonics, Department of Electrical and Computer Engineering, Duke University, Durham, North Carolina, 27708 (United States)

    2015-11-16

    We present a dynamic metamaterial aperture for use in computational imaging schemes at microwave frequencies. The aperture consists of an array of complementary, resonant metamaterial elements patterned into the upper conductor of a microstrip line. Each metamaterial element contains two diodes connected to an external control circuit such that the resonance of the metamaterial element can be damped by application of a bias voltage. Through applying different voltages to the control circuit, select subsets of the elements can be switched on to create unique radiation patterns that illuminate the scene. Spatial information of an imaging domain can thus be encoded onto this set of radiation patterns, or measurements, which can be processed to reconstruct the targets in the scene using compressive sensing algorithms. We discuss the design and operation of a metamaterial imaging system and demonstrate reconstructed images with a 10:1 compression ratio. Dynamic metamaterial apertures can potentially be of benefit in microwave or millimeter wave systems such as those used in security screening and through-wall imaging. In addition, feature-specific or adaptive imaging can be facilitated through the use of the dynamic aperture.

  15. Gd-DTPA-enhanced dynamic MR imaging

    International Nuclear Information System (INIS)

    Frank, J.A.; Choyke, P.L.; Carvlin, M.; Inscoe, S.; Austin, H.; Dwyer, A.J.; Girton, M.; Black, J.

    1988-01-01

    This paper describes dynamic enhanced renal MR imaging, a new method of identifying specific derangements in renal function. Various diuretics were employed in 45 animal experiments to demonstrate the effects on the normal renal enhancement pattern (EP) after Gd-DTPA. Since different diuretics, osmotic (O), carbonic anhydrase (CA), and loop (L), are active at different sites, specific EP alterations are observed. Imaging was performed with 32 5.1-second sequential gradient recalled acquisition in a steady state images following a bolus of Gd-DTPA

  16. Improving InSAR geodesy using Global Atmospheric Models

    Science.gov (United States)

    Jolivet, Romain; Agram, Piyush Shanker; Lin, Nina Y.; Simons, Mark; Doin, Marie-Pierre; Peltzer, Gilles; Li, Zhenghong

    2014-03-01

    Spatial and temporal variations of pressure, temperature, and water vapor content in the atmosphere introduce significant confounding delays in interferometric synthetic aperture radar (InSAR) observations of ground deformation and bias estimates of regional strain rates. Producing robust estimates of tropospheric delays remains one of the key challenges in increasing the accuracy of ground deformation measurements using InSAR. Recent studies revealed the efficiency of global atmospheric reanalysis to mitigate the impact of tropospheric delays, motivating further exploration of their potential. Here we explore the effectiveness of these models in several geographic and tectonic settings on both single interferograms and time series analysis products. Both hydrostatic and wet contributions to the phase delay are important to account for. We validate these path delay corrections by comparing with estimates of vertically integrated atmospheric water vapor content derived from the passive multispectral imager Medium-Resolution Imaging Spectrometer, onboard the Envisat satellite. Generally, the performance of the prediction depends on the vigor of atmospheric turbulence. We discuss (1) how separating atmospheric and orbital contributions allows one to better measure long-wavelength deformation and (2) how atmospheric delays affect measurements of surface deformation following earthquakes, and (3) how such a method allows us to reduce biases in multiyear strain rate estimates by reducing the influence of unevenly sampled seasonal oscillations of the tropospheric delay.

  17. Women's preferences of dynamic spectral imaging colposcopy

    NARCIS (Netherlands)

    Louwers, J.A.; Zaal, Afra; Kocken, M.; Papagiannakis, E.; Meijer, C.J.; Verheijen, RHM

    2015-01-01

    Background: The focus of testing the dynamic spectral imaging (DSI) colposcope has been on the technical characteristics and clinical performance. However, aspects from a patient’s perspective are just as important. Methods: This study was designed as a substudy of the DSI validation study, a

  18. Estimating snow water equivalent (SWE) using interferometric synthetic aperture radar (InSAR)

    Science.gov (United States)

    Deeb, Elias J.

    interaction with the snowpack being complex, the methodology for using InSAR to estimate SWE shows great promise when considering NASA's proposed L-Band, weekly repeat time interval, interferometric DESDynI (Deformation, Ecosystem Structure, and Dynamics of Ice) mission.

  19. Quantifying sub-pixel urban impervious surface through fusion of optical and inSAR imagery

    Science.gov (United States)

    Yang, L.; Jiang, L.; Lin, H.; Liao, M.

    2009-01-01

    In this study, we explored the potential to improve urban impervious surface modeling and mapping with the synergistic use of optical and Interferometric Synthetic Aperture Radar (InSAR) imagery. We used a Classification and Regression Tree (CART)-based approach to test the feasibility and accuracy of quantifying Impervious Surface Percentage (ISP) using four spectral bands of SPOT 5 high-resolution geometric (HRG) imagery and three parameters derived from the European Remote Sensing (ERS)-2 Single Look Complex (SLC) SAR image pair. Validated by an independent ISP reference dataset derived from the 33 cm-resolution digital aerial photographs, results show that the addition of InSAR data reduced the ISP modeling error rate from 15.5% to 12.9% and increased the correlation coefficient from 0.71 to 0.77. Spatially, the improvement is especially noted in areas of vacant land and bare ground, which were incorrectly mapped as urban impervious surfaces when using the optical remote sensing data. In addition, the accuracy of ISP prediction using InSAR images alone is only marginally less than that obtained by using SPOT imagery. The finding indicates the potential of using InSAR data for frequent monitoring of urban settings located in cloud-prone areas.

  20. Dynamic high resolution imaging of rats

    International Nuclear Information System (INIS)

    Miyaoka, R.S.; Lewellen, T.K.; Bice, A.N.

    1990-01-01

    A positron emission tomography with the sensitivity and resolution to do dynamic imaging of rats would be an invaluable tool for biological researchers. In this paper, the authors determine the biological criteria for dynamic positron emission imaging of rats. To be useful, 3 mm isotropic resolution and 2-3 second time binning were necessary characteristics for such a dedicated tomograph. A single plane in which two objects of interest could be imaged simultaneously was considered acceptable. Multi-layered detector designs were evaluated as a possible solution to the dynamic imaging and high resolution imaging requirements. The University of Washington photon history generator was used to generate data to investigate a tomograph's sensitivity to true, scattered and random coincidences for varying detector ring diameters. Intrinsic spatial uniformity advantages of multi-layered detector designs over conventional detector designs were investigated using a Monte Carlo program. As a result, a modular three layered detector prototype is being developed. A module will consist of a layer of five 3.5 mm wide crystals and two layers of six 2.5 mm wide crystals. The authors believe adequate sampling can be achieved with a stationary detector system using these modules. Economical crystal decoding strategies have been investigated and simulations have been run to investigate optimum light channeling methods for block decoding strategies. An analog block decoding method has been proposed and will be experimentally evaluated to determine whether it can provide the desired performance

  1. Dynamic MR imaging of the sellar region

    International Nuclear Information System (INIS)

    Takahashi, M.; Sakamoto, Y.; Korogi, Y.; Nishimura, R.; Yoshizumi, K.; Ushio, Y.

    1990-01-01

    This paper reports on sequential and differential enhancement of the normal and abnormal structures of the sellar regions were evaluated with dynamic MR imaging for the diagnosis of sellar and parasellar tumors. Dynamic MR imaging was performed on a 1.5-T superconductive unit, with rapid injection of Gd-DTPA (0.1 mmol/kg body weight) followed by serial spin-echo (TR 220/TE 15 msec) images of the sellar region for 3-5 minutes. The first structures visualized were the cavernous sinus, infundibulum, and posterior pituitary lobe within 30 seconds, followed by enhancement of the anterior pituitary lobe near the infundibulum in 50 seconds and the peripheral portion of the anterior pituitary lobe in 80 seconds

  2. Dynamic Image Stitching for Panoramic Video

    Directory of Open Access Journals (Sweden)

    Jen-Yu Shieh

    2014-10-01

    Full Text Available The design of this paper is based on the Dynamic image titching for panoramic video. By utilizing OpenCV visual function data library and SIFT algorithm as the basis for presentation, this article brings forward Gaussian second differenced MoG which is processed basing on DoG Gaussian Difference Map to reduce order in synthesizing dynamic images and simplify the algorithm of the Gaussian pyramid structure. MSIFT matches with overlapping segmentation method to simplify the scope of feature extraction in order to enhance speed. And through this method traditional image synthesis can be improved without having to take lots of time in calculation and being limited by space and angle. This research uses four normal Webcams and two IPCAM coupled with several-wide angle lenses. By using wide-angle lenses to monitor over a wide range of an area and then by using image stitching panoramic effect is achieved. In terms of overall image application and control interface, Microsoft Visual Studio C# is adopted to a construct software interface. On a personal computer with 2.4-GHz CPU and 2-GB RAM and with the cameras fixed to it, the execution speed is three images per second, which reduces calculation time of the traditional algorithm.

  3. Image fusion for dynamic contrast enhanced magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Leach Martin O

    2004-10-01

    Full Text Available Abstract Background Multivariate imaging techniques such as dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI have been shown to provide valuable information for medical diagnosis. Even though these techniques provide new information, integrating and evaluating the much wider range of information is a challenging task for the human observer. This task may be assisted with the use of image fusion algorithms. Methods In this paper, image fusion based on Kernel Principal Component Analysis (KPCA is proposed for the first time. It is demonstrated that a priori knowledge about the data domain can be easily incorporated into the parametrisation of the KPCA, leading to task-oriented visualisations of the multivariate data. The results of the fusion process are compared with those of the well-known and established standard linear Principal Component Analysis (PCA by means of temporal sequences of 3D MRI volumes from six patients who took part in a breast cancer screening study. Results The PCA and KPCA algorithms are able to integrate information from a sequence of MRI volumes into informative gray value or colour images. By incorporating a priori knowledge, the fusion process can be automated and optimised in order to visualise suspicious lesions with high contrast to normal tissue. Conclusion Our machine learning based image fusion approach maps the full signal space of a temporal DCE-MRI sequence to a single meaningful visualisation with good tissue/lesion contrast and thus supports the radiologist during manual image evaluation.

  4. High dynamic range imaging sensors and architectures

    CERN Document Server

    Darmont, Arnaud

    2013-01-01

    Illumination is a crucial element in many applications, matching the luminance of the scene with the operational range of a camera. When luminance cannot be adequately controlled, a high dynamic range (HDR) imaging system may be necessary. These systems are being increasingly used in automotive on-board systems, road traffic monitoring, and other industrial, security, and military applications. This book provides readers with an intermediate discussion of HDR image sensors and techniques for industrial and non-industrial applications. It describes various sensor and pixel architectures capable

  5. INSAR AND FINITE ELEMENT ANALYSIS OF GROUND DEFORMATION AT LAKE URMIA CAUSEWAY (LUC, NORTHWEST IRAN

    Directory of Open Access Journals (Sweden)

    R. Shamshiri

    2013-09-01

    Full Text Available Precise long-term deformation monitoring of causeways and bridges is of vital task for maintenance and management work related to transportation safety. In this study, we analyse the settlement of Lake Urmia Causeway (LUC, northwest Iran, using observations from InSAR and Finite Element Model (FEM simulation. For InSAR processing, we analyse 58 SAR images of ENVISAT, ALOS and TerraSAR-X (TSX using the SBAS technique to assess the settlement of embankments in the years 2003–2013. The InSAR results show deflation on both embankments with a peak velocity of > 5 cm/year in the satellite Line Of Sight (LOS direction. The InSAR observations are then used to construct a settlement compaction model for the cross section at the distance of 4 km from the most western edge of the causeway, using a 2D Finite Element Model. Our FEM results suggest that settlement of the embankments will continue in the future due to consolidation phenomenon.

  6. Cardiac fluid dynamics meets deformation imaging.

    Science.gov (United States)

    Dal Ferro, Matteo; Stolfo, Davide; De Paris, Valerio; Lesizza, Pierluigi; Korcova, Renata; Collia, Dario; Tonti, Giovanni; Sinagra, Gianfranco; Pedrizzetti, Gianni

    2018-02-20

    Cardiac function is about creating and sustaining blood in motion. This is achieved through a proper sequence of myocardial deformation whose final goal is that of creating flow. Deformation imaging provided valuable contributions to understanding cardiac mechanics; more recently, several studies evidenced the existence of an intimate relationship between cardiac function and intra-ventricular fluid dynamics. This paper summarizes the recent advances in cardiac flow evaluations, highlighting its relationship with heart wall mechanics assessed through the newest techniques of deformation imaging and finally providing an opinion of the most promising clinical perspectives of this emerging field. It will be shown how fluid dynamics can integrate volumetric and deformation assessments to provide a further level of knowledge of cardiac mechanics.

  7. Incoherent imaging using dynamically scattered coherent electrons

    International Nuclear Information System (INIS)

    Nellist, P.D.; Pennycook, S.J.

    1999-01-01

    We use a Bloch wave approach to show that, even for coherent dynamical scattering from a stationary lattice with no absorption, annular dark-field imaging in a scanning transmission electron microscope gives a direct incoherent structure image of the atomic-column positions of a zone-axis-aligned crystal. Although many Bloch waves may be excited by the probe, the detector provides a filtering effect so that the 1s-type bound states are found to dominate the image contrast for typical experimental conditions. We also find that the column intensity is related to the transverse kinetic energy of the 1s states, which gives atomic number, Z, contrast. The additional effects of phonon scattering are discussed, in particular the reasons why phonon scattering is not a prerequisite for transverse incoherence. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  8. Neutron Imaging Reveals Internal Plant Hydraulic Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Warren, Jeffrey [ORNL; Bilheux, Hassina Z [ORNL; Kang, Misun [ORNL; Voisin, Sophie [ORNL; Cheng, Chu-Lin [ORNL; Horita, Jusuke [ORNL; Perfect, Edmund [ORNL

    2013-01-01

    Many terrestrial ecosystem processes are constrained by water availability and transport within the soil. Knowledge of plant water fluxes is thus critical for assessing mechanistic processes linked to biogeochemical cycles, yet resolution of root structure and xylem water transport dynamics has been a particularly daunting task for the ecologist. Through neutron imaging, we demonstrate the ability to non-invasively monitor individual root functionality and water fluxes within Zea mays L. (maize) and Panicum virgatum L. (switchgrass) seedlings growing in a sandy medium. Root structure and growth were readily imaged by neutron radiography and neutron computed tomography. Seedlings were irrigated with water or deuterium oxide and imaged through time as a growth lamp was cycled on to alter leaf demand for water. Sub-millimeter scale resolution reveals timing and magnitudes of root water uptake, redistribution within the roots, and root-shoot hydraulic linkages, relationships not well characterized by other techniques.

  9. There is no one-size-fits-all product for InSAR; on the inclusion of contextual information for geodetically-proof InSAR data products

    Science.gov (United States)

    Hanssen, R. F.

    2017-12-01

    In traditional geodesy, one is interested in determining the coordinates, or the change in coordinates, of predefined benchmarks. These benchmarks are clearly identifiable and are especially established to be representative of the signal of interest. This holds, e.g., for leveling benchmarks, for triangulation/trilateration benchmarks, and for GNSS benchmarks. The desired coordinates are not identical to the basic measurements, and need to be estimated using robust estimation procedures, where the stochastic nature of the measurements is taken into account. For InSAR, however, the `benchmarks' are not predefined. In fact, usually we do not know where an effective benchmark is located, even though we can determine its dynamic behavior pretty well. This poses several significant problems. First, we cannot describe the quality of the measurements, unless we already know the dynamic behavior of the benchmark. Second, if we don't know the quality of the measurements, we cannot compute the quality of the estimated parameters. Third, rather harsh assumptions need to be made to produce a result. These (usually implicit) assumptions differ between processing operators and the used software, and are severely affected by the amount of available data. Fourth, the `relative' nature of the final estimates is usually not explicitly stated, which is particularly problematic for non-expert users. Finally, whereas conventional geodesy applies rigorous testing to check for measurement or model errors, this is hardly ever done in InSAR-geodesy. These problems make it rather impossible to provide a precise, reliable, repeatable, and `universal' InSAR product or service. Here we evaluate the requirements and challenges to move towards InSAR as a geodetically-proof product. In particular this involves the explicit inclusion of contextual information, as well as InSAR procedures, standards and a technical protocol, supported by the International Association of Geodesy and the

  10. The InSAR Scientific Computing Environment (ISCE): A Python Framework for Earth Science

    Science.gov (United States)

    Rosen, P. A.; Gurrola, E. M.; Agram, P. S.; Sacco, G. F.; Lavalle, M.

    2015-12-01

    The InSAR Scientific Computing Environment (ISCE, funded by NASA ESTO) provides a modern computing framework for geodetic image processing of InSAR data from a diverse array of radar satellites and aircraft. ISCE is both a modular, flexible, and extensible framework for building software components and applications as well as a toolbox of applications for processing raw or focused InSAR and Polarimetric InSAR data. The ISCE framework contains object-oriented Python components layered to construct Python InSAR components that manage legacy Fortran/C InSAR programs. Components are independently configurable in a layered manner to provide maximum control. Polymorphism is used to define a workflow in terms of abstract facilities for each processing step that are realized by specific components at run-time. This enables a single workflow to work on either raw or focused data from all sensors. ISCE can serve as the core of a production center to process Level-0 radar data to Level-3 products, but is amenable to interactive processing approaches that allow scientists to experiment with data to explore new ways of doing science with InSAR data. The NASA-ISRO SAR (NISAR) Mission will deliver data of unprecedented quantity and quality, making possible global-scale studies in climate research, natural hazards, and Earth's ecosystems. ISCE is planned as the foundational element in processing NISAR data, enabling a new class of analyses that take greater advantage of the long time and large spatial scales of these new data. NISAR will be but one mission in a constellation of radar satellites in the future delivering such data. ISCE currently supports all publicly available strip map mode space-borne SAR data since ERS and is expected to include support for upcoming missions. ISCE has been incorporated into two prototype cloud-based systems that have demonstrated its elasticity in addressing larger data processing problems in a "production" context and its ability to be

  11. Dynamic MR imaging of mandibular osteoradionecrosis

    International Nuclear Information System (INIS)

    Store, G.; Smith, H.J.; Larheim, T.A.

    2000-01-01

    Osteoradionecrotic bone has been characterised as hypovascular and metabolically inactive tissue with impaired perfusion. The present study was conducted to determine if dynamic contrast-enhanced MR imaging could provide additional information about the vascularity of radionecrotic mandibular bone. Dynamic contrast-enhanced MR imaging was performed on 10 patients with mandibular osteoradionecrosis (ORN), and on 6 patients, irradiated for oropharyngeal tumours, without symptoms or signs of ORN. Nine patients in the ORN group received a series of 20 hyperbaric oxygen (HBO) treatments, after which the dynamic MR investigation was repeated. Radiation per se did not lead to increased contrast enhancement, whereas all patients with ORN showed marked contrast enhancement of the osteoradionecrotic bone marrow. After HBO treatment, pathological contrast enhancement of the abnormal bone marrow could still be seen, but the rate of enhancement was less than before in 7 of 9 patients. Two patients had an increase in the enhancement rate. The findings suggest the existence of an increased and patent microvasculature

  12. Slope Stability Assessment of the Sarcheshmeh Landslide, Northeast Iran, Investigated Using InSAR and GPS Observations

    Directory of Open Access Journals (Sweden)

    Mahdi Motagh

    2013-07-01

    Full Text Available The detection and monitoring of mass movement of susceptible slopes plays a key role in mitigating hazards and potential damage associated with creeping slopes and landslides. In this paper, we use observations from both Interferometric Synthetic Aperture Radar (InSAR and Global Positioning System (GPS to assess the slope stability of the Sarcheshmeh ancient landslide in the North Khorasan province of northeast Iran. InSAR observations were obtained by the time-series analysis of Envisat SAR images covering 2004–2006, whereas repeated GPS observations were conducted by campaign measurements during 2010–2012. Surface displacement maps of the Sarcheshmeh landslide obtained from InSAR and GPS are both indicative of slope stability. Hydrogeological analysis suggests that the multi-year drought and lower than average precipitation levels over the last decade might have contributed to the current dormancy of the Sarcheshmeh landslide.

  13. INSAR observations of the DPRK event series

    Science.gov (United States)

    Mellors, R. J.; Ford, S. R.; Walter, W. R.

    2017-12-01

    Interferometric synthetic aperture radar (INSAR) data have revealed signals associated with the recent DPRK events in 2016 and 2017. These signals include decorrelation and indications of subsidence. Both standard phase differences and amplitude offsets are calculated. We show results of INSAR analysis as conducted using C and L band data and investigate the causes of the decorrelation (e.g. subsidence, landslide, or spall) and compare the observed signal with numerical models of deformation and seismic observations. A time series approach is applied to constrain post-event deformation at the weeks to months' timescale. We compare the INSAR observations of the DPRK tests with previous observations of events at other source regions using ERS archive data, which revealed a variety of post-seismic signatures. The signatures are evaluated with respect to the known geology and causes, including long-term surface relaxation and possible groundwater/thermal effects. Particular focus is on the sites on Pahute and Rainier Mesa, which displayed long-term subsidence signals that extended for several years after the explosions. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. Lawrence Livermore National Security, LLC

  14. Solar Flare Dynamic Microwave Imaging with EOVSA

    Science.gov (United States)

    Gary, D. E.; Chen, B.; Nita, G. M.; Fleishman, G. D.; Yu, S.; White, S. M.; Hurford, G. J.; McTiernan, J. M.

    2017-12-01

    The Expanded Owens Valley Solar Array (EOVSA) is both an expansion of our existing solar array and serves as a prototype for a much larger future project, the Frequency Agile Solar Radiotelescope (FASR). EOVSA is now complete, and is producing daily imaging of the full solar disk, including active regions and solar radio bursts at hundreds of frequencies in the range 2.8-18 GHz. We present highlights of the 1-s-cadence dynamic imaging spectroscropy of radio bursts we have obtained to date, along with deeper analysis of multi-wavelength observations and modeling of a well-observed burst. These observations are revealing the full life-cycle of the trapped population of high-energy electrons, from their initial acceleration and subsequent energy-evolution to their eventual decay through escape and thermalization. All of our data are being made available for download in both quick-look image form and in the form of the community-standard CASA measurement sets for subsequent imaging and analysis.

  15. a High Precision dem Extraction Method Based on Insar Data

    Science.gov (United States)

    Wang, Xinshuang; Liu, Lingling; Shi, Xiaoliang; Huang, Xitao; Geng, Wei

    2018-04-01

    In the 13th Five-Year Plan for Geoinformatics Business, it is proposed that the new InSAR technology should be applied to surveying and mapping production, which will become the innovation driving force of geoinformatics industry. This paper will study closely around the new outline of surveying and mapping and then achieve the TerraSAR/TanDEM data of Bin County in Shaanxi Province in X band. The studying steps are as follows; Firstly, the baseline is estimated from the orbital data; Secondly, the interferometric pairs of SAR image are accurately registered; Thirdly, the interferogram is generated; Fourth, the interferometric correlation information is estimated and the flat-earth phase is removed. In order to solve the phase noise and the discontinuity phase existing in the interferometric image of phase, a GAMMA adaptive filtering method is adopted. Aiming at the "hole" problem of missing data in low coherent area, the interpolation method of low coherent area mask is used to assist the phase unwrapping. Then, the accuracy of the interferometric baseline is estimated from the ground control points. Finally, 1 : 50000 DEM is generated, and the existing DEM data is used to verify the accuracy through statistical analysis. The research results show that the improved InSAR data processing method in this paper can obtain the high-precision DEM of the study area, exactly the same with the topography of reference DEM. The R2 can reach to 0.9648, showing a strong positive correlation.

  16. High dynamic range image acquisition based on multiplex cameras

    Science.gov (United States)

    Zeng, Hairui; Sun, Huayan; Zhang, Tinghua

    2018-03-01

    High dynamic image is an important technology of photoelectric information acquisition, providing higher dynamic range and more image details, and it can better reflect the real environment, light and color information. Currently, the method of high dynamic range image synthesis based on different exposure image sequences cannot adapt to the dynamic scene. It fails to overcome the effects of moving targets, resulting in the phenomenon of ghost. Therefore, a new high dynamic range image acquisition method based on multiplex cameras system was proposed. Firstly, different exposure images sequences were captured with the camera array, using the method of derivative optical flow based on color gradient to get the deviation between images, and aligned the images. Then, the high dynamic range image fusion weighting function was established by combination of inverse camera response function and deviation between images, and was applied to generated a high dynamic range image. The experiments show that the proposed method can effectively obtain high dynamic images in dynamic scene, and achieves good results.

  17. Usefulness of dynamic magnetic resonance imaging in pituitary microadenomas

    International Nuclear Information System (INIS)

    Rhee, Chang Soo; Lee, Eun Young; Joo, Yang Gu; Kim, Hong; Lee, Hee Jung; Sch, Soo Ji

    1996-01-01

    To investigate the usefulness of dynamic MR imaging in the diagnosis of pituitary microadenomas. Dynamic MR imaging was performed in 31 patients with suspicious pituitary microadinoma. The MR examination was performed on a 2.0T or 1.5T superconductive MR unit using spin echo(SE) technique with a repetition time of 200msec, echo time of 15 msec, 128X256 matrix and one excitation. Actual sampling time per image was 26 seconds. The field of view was 25cm and a section thickness if 3 mm with 2mm gap was chose. After a rapid hand injection(2-3ml/sec) of Gd-DTPA(0.1 mmol/kg of body weight), dynamic coronal plane MR images were obtained every 20-30 seconds for 3-5 minutes. Between never and ten serial images were usually obtained. After dynamic MR imaging, toutine SE T1-weighted images(T1W1) were obtained in the same plane as dynamic images, and detection rates of pituitary microadinoma using dynamic MR imaging and using routine enhanced T1W1, were retrospectively compared. On early dynamic images(30-90 seconds), 23 of 31 adenomas(74.2%) were well visualized at 30-second dynamic image. On late dynamic images(120-180 seconds), six microadeomas(19.4%) were well-visualized and ; two(6.5%) were well-visualized on toutine Gd-DTPA enhanced T1W1. dynamic MR imaging with Gd-DTPA bolus injection was the most useful technique for the detection of pituitary microadenoma, especially on early-phase dynamic images

  18. InSAR detects increase in surface subsidence caused by an Arctic tundra fire

    Science.gov (United States)

    Liu, Lin; Jafarov, Elchin E.; Schaefer, Kevin M.; Jones, Benjamin M.; Zebker, Howard A.; Williams, Christopher A.; Rogan, John; Zhang, Tingjun

    2014-01-01

    Wildfire is a major disturbance in the Arctic tundra and boreal forests, having a significant impact on soil hydrology, carbon cycling, and permafrost dynamics. This study explores the use of the microwave Interferometric Synthetic Aperture Radar (InSAR) technique to map and quantify ground surface subsidence caused by the Anaktuvuk River fire on the North Slope of Alaska. We detected an increase of up to 8 cm of thaw-season ground subsidence after the fire, which is due to a combination of thickened active layer and permafrost thaw subsidence. Our results illustrate the effectiveness and potential of using InSAR to quantify fire impacts on the Arctic tundra, especially in regions underlain by ice-rich permafrost. Our study also suggests that surface subsidence is a more comprehensive indicator of fire impacts on ice-rich permafrost terrain than changes in active layer thickness alone.

  19. INSAR For Early Warning Of Possible Highway Instability Over Undermined Area Of Ostrava

    Science.gov (United States)

    Lazecky, Milan; Kacmarik, Michal; Rapant, Petr

    2012-01-01

    A part of czech highway D1 connecting Ostrava with Prague and Poland, is built over an undermined area of Ostrava-Svinov. Since the end of 2010, this part of the highway is fully operational. Because of undermining, a subsidence can be expected, however with a very slow rate since the mines are no more active in this area. Several TerraSAR-X images from 2011 are investigated interferometrically in order to estimate a precise deformation model. Subjects of interest are movements of newly built highway bridges, banks and close neighbourhood. Existing C-band multitemporal InSAR processing results of ERS and Envisat are available from an earlier period that reveil a slow trend of residual subsidence. In this project, InSAR will be investigated as a tool for an early warning for highway stability.

  20. Image Alignment for Multiple Camera High Dynamic Range Microscopy

    OpenAIRE

    Eastwood, Brian S.; Childs, Elisabeth C.

    2012-01-01

    This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability fo...

  1. ARIA: Delivering state-of-the-art InSAR products to end users

    Science.gov (United States)

    Agram, P. S.; Owen, S. E.; Hua, H.; Manipon, G.; Sacco, G. F.; Bue, B. D.; Fielding, E. J.; Yun, S. H.; Simons, M.; Webb, F.; Rosen, P. A.; Lundgren, P.; Liu, Z.

    2016-12-01

    Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards aims to bring state-of-the-art geodetic imaging capabilities to an operational level in support of local, national, and international hazard response communities. ARIA project's first foray into operational generation of InSAR products was with Calimap Project, in collaboration with ASI-CIDOT, using X-band data from the Cosmo-SkyMed constellation. Over the last year, ARIA's processing infrastructure has been significantly upgraded to exploit the free stream of high quality C-band SAR data from ESA's Sentinel-1 mission and related algorithmic improvements to the ISCE software. ARIA's data system can now operationally generate geocoded unwrapped phase and coherence products in GIS-friendly formats from Sentinel-1 TOPS mode data in an automated fashion, and this capability is currently being exercised various study sites across the United States including Hawaii, Central California, Iceland and South America. The ARIA team, building on the experience gained from handling X-band data and C-band data, has also built an automated machine learning-based classifier to label the auto-generated interferograms based on phase unwrapping quality. These high quality "time-series ready" InSAR products generated using state-of-the-art processing algorithms can be accessed by end users using two different mechanisms - 1) a Faceted-search interface that includes browse imagery for quick visualization and 2) an ElasticSearch-based API to enable bulk automated download, post-processing and time-series analysis. In this talk, we will present InSAR results from various global events that ARIA system has responded to. We will also discuss the set of geospatial big data tools including GIS libraries and API tools, that end users will need to familiarize themselves with in order to maximize the utilization of continuous stream of InSAR products from the Sentinel-1 and NISAR missions that the ARIA project will generate.

  2. Optical imaging of tumor hypoxia dynamics

    Science.gov (United States)

    Palmer, Gregory M.; Fontanella, Andrew N.; Zhang, Guoqing; Hanna, Gabi; Fraser, Cassandra L.; Dewhirst, Mark W.

    2010-11-01

    The influence of the tumor microenvironment and hypoxia plays a significant role in determining cancer progression, treatment response, and treatment resistance. That the tumor microenvironment is highly heterogeneous with significant intratumor and intertumor variability presents a significant challenge in developing effective cancer therapies. Critical to understanding the role of the tumor microenvironment is the ability to dynamically quantify oxygen levels in the vasculature and tissue in order to elucidate the roles of oxygen supply and consumption, spatially and temporally. To this end, we describe the use of hyperspectral imaging to characterize hemoglobin absorption to quantify hemoglobin content and oxygen saturation, as well as dual emissive fluorescent/phosphorescent boron nanoparticles, which serve as ratiometric indicators of tissue oxygen tension. Applying these techniques to a window-chamber tumor model illustrates the role of fluctuations in hemoglobin saturation in driving changes in tissue oxygenation, the two being significantly correlated (r = 0.77). Finally, a green-fluorescence-protein reporter for hypoxia inducible factor-1 (HIF-1) provides an endpoint for hypoxic stress in the tumor, which is used to demonstrate a significant association between tumor hypoxia dynamics and HIF-1 activity in an in vivo demonstration of the technique.

  3. Dynamic imaging with coincidence gamma camera

    International Nuclear Information System (INIS)

    Elhmassi, Ahmed

    2008-01-01

    In this paper we develop a technique to calculate dynamic parameters from data acquired using gamma-camera PET (gc PET). Our method is based on an algorithm development for dynamic SPECT, which processes all decency projection data simultaneously instead of reconstructing a series of static images individually. The algorithm was modified to account for the extra data that is obtained with gc PET (compared with SPEC). The method was tested using simulated projection data for both a SPECT and a gc PET geometry. These studies showed the ability of the code to reconstruct simulated data with a varying range of half-lives. The accuracy of the algorithm was measured in terms of the reconstructed half-life and initial activity for the simulated object. The reconstruction of gc PET data showed improvement in half-life and activity compared to SPECT data of 23% and 20%, respectively (at 50 iterations). The gc PET algorithm was also tested using data from an experimental phantom and finally, applied to a clinical dataset, where the algorithm was further modified to deal with the situation where the activity in certain pixels decreases and then increases during the acquisition. (author)

  4. Dynamic imaging through turbid media based on digital holography.

    Science.gov (United States)

    Li, Shiping; Zhong, Jingang

    2014-03-01

    Imaging through turbid media using visible or IR light instead of harmful x ray is still a challenging problem, especially in dynamic imaging. A method of dynamic imaging through turbid media using digital holography is presented. In order to match the coherence length between the dynamic object wave and the reference wave, a cw laser is used. To solve the problem of difficult focusing in imaging through turbid media, an autofocus technology is applied. To further enhance the image contrast, a spatial filtering technique is used. A description of digital holography and experiments of imaging the objects hidden in turbid media are presented. The experimental result shows that dynamic images of the objects can be achieved by the use of digital holography.

  5. Bryan Mound InSAR Analysis U.S. Strategic petroleum Reserve.

    Energy Technology Data Exchange (ETDEWEB)

    Lord, Anna C. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-06-01

    The U.S. Strategic Petroleum Reserve (SPR) is a stockpile of emergency crude oil to be tapped into if a disruption in the nation's oil supply occurs. The SPR is comprised of four salt dome sites. Subsidence surveys have been conducted either annually or biennially at all four sites over the life of the program. Monitoring of surface behavior is a first line defense to detecting possible subsurface cavern integrity issues. Over the life of the Bryan Mound site, subsidence rates over abandoned Cavern 3 have continuously been the highest at the site. In an effort to try and understand the subsurface dynamics, specifically over Bryan Mound Cavern 3, historic interferometric synthetic aperture radar (InSAR) data was acquired and processed by TRE Altamira. InSAR involves the processing of multiple satellite synthetic aperture radar scenes acquired across the same location of the Earth's surface at different times to map surface deformation. The analysis of the data has the ability to detect millimeters of motion spanning days, months, year and decades, across specific sites. The intent in regards to the Bryan Mound site was (1) to confirm the higher subsidence rates recorded over abandoned Cavern 3 indicated by land survey and (2) understand the regional surface behavior. This report describes the InSAR analysis results, how those results compare to the historical collection of land survey data, and what additional information the data has provided towards understanding the response recorded at the surface.

  6. Block adjustment of airborne InSAR based on interferogram phase and POS data

    Science.gov (United States)

    Yue, Xijuan; Zhao, Yinghui; Han, Chunming; Dou, Changyong

    2015-12-01

    High-precision surface elevation information in large scale can be obtained efficiently by airborne Interferomatric Synthetic Aperture Radar (InSAR) system, which is recently becoming an important tool to acquire remote sensing data and perform mapping applications in the area where surveying and mapping is difficult to be accomplished by spaceborne satellite or field working. . Based on the study of the three-dimensional (3D) positioning model using interferogram phase and Position and Orientation System (POS) data and block adjustment error model, a block adjustment method to produce seamless wide-area mosaic product generated from airborne InSAR data is proposed in this paper. The effect of 6 parameters, including trajectory and attitude of the aircraft, baseline length and incline angle, slant range, and interferometric phase, on the 3D positioning accuracy is quantitatively analyzed. Using the data acquired in the field campaign conducted in Mianyang county Sichuan province, China in June 2011, a mosaic seamless Digital Elevation Model (DEM) product was generated from 76 images in 4 flight strips by the proposed block adjustment model. The residuals of ground control points (GCPs), the absolute positioning accuracy of check points (CPs) and the relative positioning accuracy of tie points (TPs) both in same and adjacent strips were assessed. The experimental results suggest that the DEM and Digital Orthophoto Map (DOM) product generated by the airborne InSAR data with sparse GCPs can meet mapping accuracy requirement at scale of 1:10 000.

  7. Investigation on Insar Time Series Deformation Model Considering Rheological Parameters for Soft Clay Subgrade Monitoring

    Science.gov (United States)

    Xing, X.; Yuan, Z.; Chen, L. F.; Yu, X. Y.; Xiao, L.

    2018-04-01

    The stability control is one of the major technical difficulties in the field of highway subgrade construction engineering. Building deformation model is a crucial step for InSAR time series deformation monitoring. Most of the InSAR deformation models for deformation monitoring are pure empirical mathematical models, without considering the physical mechanism of the monitored object. In this study, we take rheology into consideration, inducing rheological parameters into traditional InSAR deformation models. To assess the feasibility and accuracy for our new model, both simulation and real deformation data over Lungui highway (a typical highway built on soft clay subgrade in Guangdong province, China) are investigated with TerraSAR-X satellite imagery. In order to solve the unknows of the non-linear rheological model, three algorithms: Gauss-Newton (GN), Levenberg-Marquarat (LM), and Genetic Algorithm (GA), are utilized and compared to estimate the unknown parameters. Considering both the calculation efficiency and accuracy, GA is chosen as the final choice for the new model in our case study. Preliminary real data experiment is conducted with use of 17 TerraSAR-X Stripmap images (with a 3-m resolution). With the new deformation model and GA aforementioned, the unknown rheological parameters over all the high coherence points are obtained and the LOS deformation (the low-pass component) sequences are generated.

  8. Remote Monitoring of Groundwater Overdraft Using GRACE and InSAR

    Science.gov (United States)

    Scher, C.; Saah, D.

    2017-12-01

    Gravity Recovery and Climate Experiment (GRACE) data paired with radar-derived analyses of volumetric changes in aquifer storage capacity present a viable technique for remote monitoring of aquifer depletion. Interferometric Synthetic Aperture Radar (InSAR) analyses of ground level subsidence can account for a significant portion of mass loss observed in GRACE data and provide information on point-sources of overdraft. This study summed one water-year of GRACE monthly mass change grids and delineated regions with negative water storage anomalies for further InSAR analyses. Magnitude of water-storage anomalies observed by GRACE were compared to InSAR-derived minimum volumetric changes in aquifer storage capacity as a result of measurable compaction at the surface. Four major aquifers were selected within regions where GRACE observed a net decrease in water storage (Central Valley, California; Mekong Delta, Vietnam; West Bank, occupied Palestinian Territory; and the Indus Basin, South Asia). Interferogram imagery of the extent and magnitude of subsidence within study regions provided estimates for net minimum volume of groundwater extracted between image acquisitions. These volumetric estimates were compared to GRACE mass change grids to resolve a percent contribution of mass change observed by GRACE likely due to groundwater overdraft. Interferograms revealed characteristic cones of depression within regions of net mass loss observed by GRACE, suggesting point-source locations of groundwater overdraft and demonstrating forensic potential for the use of InSAR and GRACE data in remote monitoring of aquifer depletion. Paired GRACE and InSAR analyses offer a technique to increase the spatial and temporal resolution of remote applications for monitoring groundwater overdraft in addition to providing a novel parameter - measurable vertical deformation at the surface - to global groundwater models.

  9. Imaging complex nutrient dynamics in mycelial networks.

    Science.gov (United States)

    Fricker, M D; Lee, J A; Bebber, D P; Tlalka, M; Hynes, J; Darrah, P R; Watkinson, S C; Boddy, L

    2008-08-01

    Transport networks are vital components of multi-cellular organisms, distributing nutrients and removing waste products. Animal cardiovascular and respiratory systems, and plant vasculature, are branching trees whose architecture is thought to determine universal scaling laws in these organisms. In contrast, the transport systems of many multi-cellular fungi do not fit into this conceptual framework, as they have evolved to explore a patchy environment in search of new resources, rather than ramify through a three-dimensional organism. These fungi grow as a foraging mycelium, formed by the branching and fusion of threadlike hyphae, that gives rise to a complex network. To function efficiently, the mycelial network must both transport nutrients between spatially separated source and sink regions and also maintain its integrity in the face of continuous attack by mycophagous insects or random damage. Here we review the development of novel imaging approaches and software tools that we have used to characterise nutrient transport and network formation in foraging mycelia over a range of spatial scales. On a millimetre scale, we have used a combination of time-lapse confocal imaging and fluorescence recovery after photobleaching to quantify the rate of diffusive transport through the unique vacuole system in individual hyphae. These data then form the basis of a simulation model to predict the impact of such diffusion-based movement on a scale of several millimetres. On a centimetre scale, we have used novel photon-counting scintillation imaging techniques to visualize radiolabel movement in small microcosms. This approach has revealed novel N-transport phenomena, including rapid, preferential N-resource allocation to C-rich sinks, induction of simultaneous bi-directional transport, abrupt switching between different pre-existing transport routes, and a strong pulsatile component to transport in some species. Analysis of the pulsatile transport component using Fourier

  10. Image Alignment for Multiple Camera High Dynamic Range Microscopy.

    Science.gov (United States)

    Eastwood, Brian S; Childs, Elisabeth C

    2012-01-09

    This paper investigates the problem of image alignment for multiple camera high dynamic range (HDR) imaging. HDR imaging combines information from images taken with different exposure settings. Combining information from multiple cameras requires an alignment process that is robust to the intensity differences in the images. HDR applications that use a limited number of component images require an alignment technique that is robust to large exposure differences. We evaluate the suitability for HDR alignment of three exposure-robust techniques. We conclude that image alignment based on matching feature descriptors extracted from radiant power images from calibrated cameras yields the most accurate and robust solution. We demonstrate the use of this alignment technique in a high dynamic range video microscope that enables live specimen imaging with a greater level of detail than can be captured with a single camera.

  11. A framework of region-based dynamic image fusion

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-hua; QIN Zheng; LIU Yu

    2007-01-01

    A new framework of region-based dynamic image fusion is proposed. First, the technique of target detection is applied to dynamic images (image sequences) to segment images into different targets and background regions. Then different fusion rules are employed in different regions so that the target information is preserved as much as possible. In addition, steerable non-separable wavelet frame transform is used in the process of multi-resolution analysis, so the system achieves favorable characters of orientation and invariant shift. Compared with other image fusion methods, experimental results showed that the proposed method has better capabilities of target recognition and preserves clear background information.

  12. Dynamic flat panel detector versus image intensifier in cardiac imaging: dose and image quality

    Science.gov (United States)

    Vano, E.; Geiger, B.; Schreiner, A.; Back, C.; Beissel, J.

    2005-12-01

    The practical aspects of the dosimetric and imaging performance of a digital x-ray system for cardiology procedures were evaluated. The system was configured with an image intensifier (II) and later upgraded to a dynamic flat panel detector (FD). Entrance surface air kerma (ESAK) to phantoms of 16, 20, 24 and 28 cm of polymethyl methacrylate (PMMA) and the image quality of a test object were measured. Images were evaluated directly on the monitor and with numerical methods (noise and signal-to-noise ratio). Information contained in the DICOM header for dosimetry audit purposes was also tested. ESAK values per frame (or kerma rate) for the most commonly used cine and fluoroscopy modes for different PMMA thicknesses and for field sizes of 17 and 23 cm for II, and 20 and 25 cm for FD, produced similar results in the evaluated system with both technologies, ranging between 19 and 589 µGy/frame (cine) and 5 and 95 mGy min-1 (fluoroscopy). Image quality for these dose settings was better for the FD version. The 'study dosimetric report' is comprehensive, and its numerical content is sufficiently accurate. There is potential in the future to set those systems with dynamic FD to lower doses than are possible in the current II versions, especially for digital cine runs, or to benefit from improved image quality.

  13. Accelerated Scientific InSAR Processing, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Neva Ridge Technologies proposes to develop a suite of software tools for the analysis of SAR and InSAR data, focused on having a robust and adopted capability well...

  14. INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR TECHNOLOGY AND GEOMORPHOLOGY INTERPRETATION

    Directory of Open Access Journals (Sweden)

    M. Maghsoudi

    2013-09-01

    Full Text Available Geomorphology is briefly the study of landforms and their formative processes on the surface of the planet earth as human habitat. The landforms evolution and the formative processes can best be studied by technologies with main application in study of elevation. Interferometric Synthetic Aperture Radar (InSAR is the appropriate technology for this application. With phase differences calculations in radar waves, the results of this technology can extensively be interpreted for geomorphologic researches. The purpose of the study is to review the geomorphologic studies using InSAR and also the technical studies about InSAR with geomorphologic interpretations. This study states that the InSAR technology can be recommended to be employed as a fundamental for geomorphology researches.

  15. Dynamic MR imaging in Tolosa-Hunt syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Haque, Tabassum Laz; Miki, Yukio; Kashii, Satoshi; Yamamoto, Akira; Kanagaki, Mitsunori; Takahashi, Takahiro; Fushimi, Yasutaka; Asato, Reinin; Murase, Nagako; Shibasaki, Hiroshi; Konishi, Junji

    2004-09-01

    Objective: To evaluate the cavernous sinuses with dynamic magnetic resonance (MR) imaging in patients with Tolosa-Hunt syndrome (THS). Methods: The sellar and parasellar regions of five patients with THS and 12 control subjects were examined with dynamic MR (1.5 T) imaging in the coronal plane. Dynamic images were obtained with spin-echo (SE) sequences in three patients, and with fast spin-echo (FSE) sequences in two patients and control subjects. Conventional MR images of the cranium including sellar and parasellar regions were also obtained on T1-weighted pre- and post-contrast SE, and T2-weighted FSE sequences in the coronal plane. Results: MR images revealed affected cavernous sinus with bulged convex lateral wall in three patients and concave lateral wall in two patients. In all control subjects, cavernous sinuses were observed with concave lateral wall. The signal intensity on T1- and T2-weighted images and contrast enhancement on post-contrast images of the affected cavernous sinuses in patients were similar to those of the unaffected cavernous sinuses in patients and control subjects. The dynamic images in all patients disclosed small areas adjacent to the cranial nerve filling-defects within the enhanced venous spaces of the affected cavernous sinus, which showed slow and gradual enhancement from the early to the late dynamic images. No such gradually enhancing area was observed in control subjects except one. The follow-up dynamic MR images after corticosteroid therapy revealed complete resolution of the gradually enhancing areas in the previously affected cavernous sinus. Conclusion: Dynamic MR imaging may facilitate the diagnosis of THS.

  16. Dynamic MR imaging in Tolosa-Hunt syndrome

    International Nuclear Information System (INIS)

    Haque, Tabassum Laz; Miki, Yukio; Kashii, Satoshi; Yamamoto, Akira; Kanagaki, Mitsunori; Takahashi, Takahiro; Fushimi, Yasutaka; Asato, Reinin; Murase, Nagako; Shibasaki, Hiroshi; Konishi, Junji

    2004-01-01

    Objective: To evaluate the cavernous sinuses with dynamic magnetic resonance (MR) imaging in patients with Tolosa-Hunt syndrome (THS). Methods: The sellar and parasellar regions of five patients with THS and 12 control subjects were examined with dynamic MR (1.5 T) imaging in the coronal plane. Dynamic images were obtained with spin-echo (SE) sequences in three patients, and with fast spin-echo (FSE) sequences in two patients and control subjects. Conventional MR images of the cranium including sellar and parasellar regions were also obtained on T1-weighted pre- and post-contrast SE, and T2-weighted FSE sequences in the coronal plane. Results: MR images revealed affected cavernous sinus with bulged convex lateral wall in three patients and concave lateral wall in two patients. In all control subjects, cavernous sinuses were observed with concave lateral wall. The signal intensity on T1- and T2-weighted images and contrast enhancement on post-contrast images of the affected cavernous sinuses in patients were similar to those of the unaffected cavernous sinuses in patients and control subjects. The dynamic images in all patients disclosed small areas adjacent to the cranial nerve filling-defects within the enhanced venous spaces of the affected cavernous sinus, which showed slow and gradual enhancement from the early to the late dynamic images. No such gradually enhancing area was observed in control subjects except one. The follow-up dynamic MR images after corticosteroid therapy revealed complete resolution of the gradually enhancing areas in the previously affected cavernous sinus. Conclusion: Dynamic MR imaging may facilitate the diagnosis of THS

  17. Robust image registration for multiple exposure high dynamic range image synthesis

    Science.gov (United States)

    Yao, Susu

    2011-03-01

    Image registration is an important preprocessing technique in high dynamic range (HDR) image synthesis. This paper proposed a robust image registration method for aligning a group of low dynamic range images (LDR) that are captured with different exposure times. Illumination change and photometric distortion between two images would result in inaccurate registration. We propose to transform intensity image data into phase congruency to eliminate the effect of the changes in image brightness and use phase cross correlation in the Fourier transform domain to perform image registration. Considering the presence of non-overlapped regions due to photometric distortion, evolutionary programming is applied to search for the accurate translation parameters so that the accuracy of registration is able to be achieved at a hundredth of a pixel level. The proposed algorithm works well for under and over-exposed image registration. It has been applied to align LDR images for synthesizing high quality HDR images..

  18. Dynamic Chest Image Analysis: Model-Based Perfusion Analysis in Dynamic Pulmonary Imaging

    Directory of Open Access Journals (Sweden)

    Kiuru Aaro

    2003-01-01

    Full Text Available The "Dynamic Chest Image Analysis" project aims to develop model-based computer analysis and visualization methods for showing focal and general abnormalities of lung ventilation and perfusion based on a sequence of digital chest fluoroscopy frames collected with the dynamic pulmonary imaging technique. We have proposed and evaluated a multiresolutional method with an explicit ventilation model for ventilation analysis. This paper presents a new model-based method for pulmonary perfusion analysis. According to perfusion properties, we first devise a novel mathematical function to form a perfusion model. A simple yet accurate approach is further introduced to extract cardiac systolic and diastolic phases from the heart, so that this cardiac information may be utilized to accelerate the perfusion analysis and improve its sensitivity in detecting pulmonary perfusion abnormalities. This makes perfusion analysis not only fast but also robust in computation; consequently, perfusion analysis becomes computationally feasible without using contrast media. Our clinical case studies with 52 patients show that this technique is effective for pulmonary embolism even without using contrast media, demonstrating consistent correlations with computed tomography (CT and nuclear medicine (NM studies. This fluoroscopical examination takes only about 2 seconds for perfusion study with only low radiation dose to patient, involving no preparation, no radioactive isotopes, and no contrast media.

  19. Staging of pancreatic ductal adenocarcinoma using dynamic MR imaging

    International Nuclear Information System (INIS)

    Murakami, Kouji; Nawano, Shigeru; Moriyama, Noriyuki; Sekiguchi, Ryuzou; Satake, Mituo; Iwata, Ryouko; Hayashi, Takayuki; Nemoto, Kazuhisa.

    1997-01-01

    Single breath-hold gradient echo images were obtained before and immediately after bolus intravenous administration of Gd-DTPA (dynamic MR imaging) in the study of the pancreas. Of 37 patients with pathologically proved pancreatic ductal adenocarcinoma, seventeen patients who underwent both dynamic MR imaging studies and curative surgery were included in this study. Correlations between histologic findings in the resected specimens and MR images were analyzed as to tumor extension and staging according to the General Rules for the Study of Pancreatic Cancer (4th Edition) published by the Japan Pancreas Society. In comparison with conventional MR images, dynamic MR imaging improved the detectability of pancreatic carcinoma and delineation of the vasculature by clarifying the margin of the tumor and the vessels. Nonenhanced T1-weighted imaging is the best sequence to estimate peripancreatic tumor extension, because the contrast between the tumor and peripancreatic fat deteriorates with the use of contrast material. There is a tendency to overestimate vascular invasion on MR images, the reason for which is considered to be the contractive nature of fibrotic change induced by pancreatic carcinoma. The diagnostic efficacy of lymph node metastasis remains insufficient on MR images because some cases show no enlargement of lymph nodes in spite of the existence of pathological metastasis. Our results suggest that dynamic MR imaging has the advantage of improving the conspicuity of the tumor and the vasculature. (author)

  20. InSAR atmospheric correction using Himawari-8 Geostationary Meteorological Satellite

    Science.gov (United States)

    Kinoshita, Y.; Nimura, T.; Furuta, R.

    2017-12-01

    The atmospheric delay effect is one of the limitations for the accurate surface displacement detection by Synthetic Aperture Radar Interferometry (InSAR). Many previous studies have attempted to mitigate the neutral atmospheric delay in InSAR (e.g. Jolivet et al. 2014; Foster et al. 2006; Kinoshita et al. 2013). Hanssen et al. (2001) investigated the relationship between the 27 hourly observations of GNSS precipitable water vapor (PWV) and the infrared brightness temperature derived from visible satellite imagery, and showed a good correlation. Here we showed a preliminary result of the newly developed method for the neutral atmospheric delay correction using the Himawari-8 Japanese geostationary meteorological satellite data. The Himawari-8 satellite is the Japanese state-of-the-art geostationary meteorological satellite that has 16 observation channels and has spatial resolutions of 0.5 km (visible) and 2.0 km (near-infrared and infrared) with an time interval of 2.5 minutes around Japan. To estimate the relationship between the satellite brightness temperature and the atmospheric delay amount. Since the InSAR atmospheric delay is principally the same as that in GNSS, we at first compared the Himawari-8 data with the GNSS zenith tropospheric delay data derived from the Japanese dense GNSS network. The comparison of them showed that the band with the wavelength of 6.9 μm had the highest correlation to the GNSS observation. Based on this result, we developed an InSAR atmospheric delay model that uses the Himawari-8 6.9 μm band data. For the model validation, we generated InSAR images from the ESA's C-band Sentinel-1 SLC data with the GAMMA SAR software. We selected two regions around Tokyo and Sapporo (both in Japan) as the test sites because of the less temporal decorrelation. The validation result showed that the delay model reasonably estimate large scale phase variation whose spatial scale was on the order of over 20 km. On the other hand, phase variations of

  1. Engaging students in geodesy: A quantitative InSAR module for undergraduate tectonics and geophysics classes

    Science.gov (United States)

    Taylor, H.; Charlevoix, D. J.; Pritchard, M. E.; Lohman, R. B.

    2013-12-01

    In the last several decades, advances in geodetic technology have allowed us to significantly expand our knowledge of processes acting on and beneath the Earth's surface. Many of these advances have come as a result of EarthScope, a community of scientists conducting multidisciplinary Earth science research utilizing freely accessible data from a variety of instruments. The geodetic component of EarthScope includes the acquisition of synthetic aperture radar (SAR) images, which are archived at the UNAVCO facility. Interferometric SAR complements the spatial and temporal coverage of GPS and allows monitoring of ground deformation in remote areas worldwide. However, because of the complex software required for processing, InSAR data are not readily accessible to most students. Even with these challenges, exposure at the undergraduate level is important for showing how geodesy can be applied in various areas of the geosciences and for promoting geodesy as a future career path. Here we present a module focused on exploring the tectonics of the western United States using InSAR data for use in undergraduate tectonics and geophysics classes. The module has two major objectives: address topics concerning tectonics in the western U.S. including Basin and Range extension, Yellowstone hotspot activity, and creep in southern California, and familiarize students with how imperfect real-world data can be manipulated and interpreted. Module questions promote critical thinking skills and data literacy by prompting students to use the information given to confront and question assumptions (e.g. 'Is there a consistency between seismic rates and permanent earthquake deformation? What other factors might need to be considered besides seismicity?'). The module consists of an introduction to the basics of InSAR and three student exercises, each focused on one of the topics listed above. Students analyze pre-processed InSAR data using MATLAB, or an Excel equivalent, and draw on GPS and

  2. Remote Sensing of Deformation of a High Concrete-Faced Rockfill Dam Using InSAR: A Study of the Shuibuya Dam, China

    Directory of Open Access Journals (Sweden)

    Wei Zhou

    2016-03-01

    Full Text Available Settlement is one of the most important deformation characteristics of high concrete faced rockfill dams (CFRDs, >100 m. High CFRDs safety would pose a great threat to the security of people’s lives and property downstream if this kind of deformation were not to be measured correctly, as traditional monitoring approaches have limitations in terms of durability, coverage, and efficiency. It has become urgent to develop new monitoring techniques to complement or replace traditional monitoring approaches for monitoring the safety and operation status of high CFRDs. This study examines the Shuibuya Dam (up to 233.5 m in height in China, which is currently the highest CFRD in the world. We used space-borne Interferometric Synthetic Aperture Radar (InSAR time series to monitor the surface deformation of the Shuibuya Dam. Twenty-one ALOS PALSAR images that span the period from 28 February 2007 to 11 March 2011 were used to map the spatial and temporal deformation of the dam. A high correlation of 0.93 between the InSAR and the in-situ monitoring results confirmed the reliability of the InSAR method; the deformation history derived from InSAR is also consistent with the in-situ settlement monitoring system. In addition, the InSAR results allow continuous investigation of dam deformation over a wide area that includes the entire dam surface as well as the surrounding area, offering a clear picture continuously of the dam deformation.

  3. RADIANCE DOMAIN COMPOSITING FOR HIGH DYNAMIC RANGE IMAGING

    Directory of Open Access Journals (Sweden)

    M.R. Renu

    2013-02-01

    Full Text Available High dynamic range imaging aims at creating an image with a range of intensity variations larger than the range supported by a camera sensor. Most commonly used methods combine multiple exposure low dynamic range (LDR images, to obtain the high dynamic range (HDR image. Available methods typically neglect the noise term while finding appropriate weighting functions to estimate the camera response function as well as the radiance map. We look at the HDR imaging problem in a denoising frame work and aim at reconstructing a low noise radiance map from noisy low dynamic range images, which is tone mapped to get the LDR equivalent of the HDR image. We propose a maximum aposteriori probability (MAP based reconstruction of the HDR image using Gibb’s prior to model the radiance map, with total variation (TV as the prior to avoid unnecessary smoothing of the radiance field. To make the computation with TV prior efficient, we extend the majorize-minimize method of upper bounding the total variation by a quadratic function to our case which has a nonlinear term arising from the camera response function. A theoretical justification for doing radiance domain denoising as opposed to image domain denoising is also provided.

  4. Non-destructive Faraday imaging of dynamically controlled ultracold atoms

    Science.gov (United States)

    Gajdacz, Miroslav; Pedersen, Poul; Mørch, Troels; Hilliard, Andrew; Arlt, Jan; Sherson, Jacob

    2013-05-01

    We investigate non-destructive measurements of ultra-cold atomic clouds based on dark field imaging of spatially resolved Faraday rotation. In particular, we pursue applications to dynamically controlled ultracold atoms. The dependence of the Faraday signal on laser detuning, atomic density and temperature is characterized in a detailed comparison with theory. In particular the destructivity per measurement is extremely low and we illustrate this by imaging the same cloud up to 2000 times. The technique is applied to avoid the effect of shot-to-shot fluctuations in atom number calibration. Adding dynamic changes to system parameters, we demonstrate single-run vector magnetic field imaging and single-run spatial imaging of the system's dynamic behavior. The method can be implemented particularly easily in standard imaging systems by the insertion of an extra polarizing beam splitter. These results are steps towards quantum state engineering using feedback control of ultracold atoms.

  5. 3D dynamic pituitary MR imaging with CAIPIRINHA: Initial experience and comparison with 2D dynamic MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fushimi, Yasutaka, E-mail: yfushimi@kuhp.kyoto-u.ac.jp [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Okada, Tomohisa; Kanagaki, Mitsunori; Yamamoto, Akira; Kanda, Yumiko; Sakamoto, Ryo [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Hojo, Masato; Takahashi, Jun C.; Miyamoto, Susumu [Department of Neurosurgery, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan); Togashi, Kaori [Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University Graduate School of Medicine, Kyoto 606-8507 (Japan)

    2014-10-15

    Objectives: To evaluate the validity of 3D dynamic pituitary MR imaging with controlled aliasing in parallel imaging results in higher acceleration (CAIPIRINHA), with special emphasis on demarcation of pituitary posterior lobe and stalk. Methods: Participants comprised 32 patients who underwent dynamic pituitary MR imaging due to pituitary or parasellar lesions. 3D dynamic MR with CAIPIRINHA was performed at 3 T with 20-s-interval, precontrast, 1st to 5th dynamic images. Normalized values and enhanced ratios (dynamic postcontrast image values divided by precontrast ones) were compared between 3D and 2D dynamic MR imaging for patients with visual identification of posterior lobe and stalk. Results: In 3D, stalk was identified in 29 patients and unidentified in 3, and posterior lobe was identified in 28 and unidentified in 4. In 2D, stalk was identified in 26 patients and unidentified in 6 patients, and posterior lobe was identified in 15 and unidentified in 17. Normalized values of pituitary posterior lobe and stalk were higher in 3D than 2D (P < 0.001). No significant difference in enhancement ratio was seen between 3D and 2D. Conclusions: 3D dynamic pituitary MR provided better identification and higher normalized values of pituitary posterior lobe and stalk than 2D.

  6. Mapping tectonic and anthropogenic processes in central California using satellite and airborne InSAR

    Science.gov (United States)

    Liu, Z.; Lundgren, P.; Liang, C.; Farr, T. G.; Fielding, E. J.

    2017-12-01

    The improved spatiotemporal resolution of surface deformation from recent satellite and airborne InSAR measurements provides a great opportunity to improve our understanding of both tectonic and non-tectonic processes. In central California the primary plate boundary fault system (San Andreas fault) lies adjacent to the San Joaquin Valley (SJV), a vast structural trough that accounts for about one-sixth of the United Sates' irrigated land and one-fifth of its extracted groundwater. The central San Andreas fault (CSAF) displays a range of fault slip behavior with creeping in its central segment that decreases towards its northwest and southeast ends, where it transitions to being fully locked. Despite much progress, many questions regarding fault and anthropogenic processes in the region still remain. In this study, we combine satellite InSAR and NASA airborne UAVSAR data to image fault and anthropogenic deformation. The UAVSAR data cover fault perpendicular swaths imaged from opposing look directions and fault parallel swaths since 2009. The much finer spatial resolution and optimized viewing geometry provide important constraints on near fault deformation and fault slip at very shallow depth. We performed a synoptic InSAR time series analysis using Sentinel-1, ALOS, and UAVSAR interferograms. We estimate azimuth mis-registration between single look complex (SLC) images of Sentinel-1 in a stack sense to achieve accurate azimuth co-registration between SLC images for low coherence and/or long interval interferometric pairs. We show that it is important to correct large-scale ionosphere features in ALOS-2 ScanSAR data for accurate deformation measurements. Joint analysis of UAVSAR and ALOS interferometry measurements show clear variability in deformation along the fault strike, suggesting variable fault creep and locking at depth and along strike. In addition to fault creep, the L-band ALOS, and especially ALOS-2 ScanSAR interferometry, show large-scale ground

  7. Panoramic images of conventional radiographs: digital panoramic dynamic images

    International Nuclear Information System (INIS)

    Schultze, M.

    2001-01-01

    The benefits of digital technic s to od ontology are evident. Instant images, the possibility to handle them, the reduction of exposition time to radiations, better quality image, better quality information, Stocking them in a compact disc, occupying very little space, allows an easy transport and duplication, as well as the possibility to transfer and save it in an electronica l support.This kind of communication allows the transmission of digital images and every other type of data, instantaneously and no matter distances or geographical borders. Anyway, we should point out that conventional and digital technic s reveal the same information contents

  8. Cardiac MR imaging: Comparison with echocardiography and dynamic CT

    International Nuclear Information System (INIS)

    Colletti, P.M.; Norris, S.; Raval, J.; Boswell, W.; Lee, K.; Ralls, P.; Haywood, J.; Halls, J.

    1986-01-01

    The authors compared gated cardiac MR imaging with two-dimensional and Doppler echocardiography and dynamic CT. Gated cardiac MR imaging (VISTA unit, 0.5 T) was performed in 55 patients with a variety of conditions. Accuracy of diagnosis was compared. CT showed arterial, valvular, and pericardial calcifications not seen on MR imaging. Many lesions were seen as well on CT as on MR imaging. Two-dimensional echocardiography was superior in demonstrating wall motion and valvular disease. MR imaging was superior in demonstrating myocardial structures

  9. Dynamic fluorescence imaging with molecular agents for cancer detection

    Science.gov (United States)

    Kwon, Sun Kuk

    Non-invasive dynamic optical imaging of small animals requires the development of a novel fluorescence imaging modality. Herein, fluorescence imaging is demonstrated with sub-second camera integration times using agents specifically targeted to disease markers, enabling rapid detection of cancerous regions. The continuous-wave fluorescence imaging acquires data with an intensified or an electron-multiplying charge-coupled device. The work presented in this dissertation (i) assessed dose-dependent uptake using dynamic fluorescence imaging and pharmacokinetic (PK) models, (ii) evaluated disease marker availability in two different xenograft tumors, (iii) compared the impact of autofluorescence in fluorescence imaging of near-infrared (NIR) vs. red light excitable fluorescent contrast agents, (iv) demonstrated dual-wavelength fluorescence imaging of angiogenic vessels and lymphatics associated with a xenograft tumor model, and (v) examined dynamic multi-wavelength, whole-body fluorescence imaging with two different fluorescent contrast agents. PK analysis showed that the uptake of Cy5.5-c(KRGDf) in xenograft tumor regions linearly increased with doses of Cy5.5-c(KRGDf) up to 1.5 nmol/mouse. Above 1.5 nmol/mouse, the uptake did not increase with doses, suggesting receptor saturation. Target to background ratio (TBR) and PK analysis for two different tumor cell lines showed that while Kaposi's sarcoma (KS1767) exhibited early and rapid uptake of Cy5.5-c(KRGDf), human melanoma tumors (M21) had non-significant TBR differences and early uptake rates similar to the contralateral normal tissue regions. The differences may be due to different compartment location of the target. A comparison of fluorescence imaging with NIR vs. red light excitable fluorescent dyes demonstrates that NIR dyes are associated with less background signal, enabling rapid tumor detection. In contrast, animals injected with red light excitable fluorescent dyes showed high autofluorescence. Dual

  10. Stereo Vision-Based High Dynamic Range Imaging Using Differently-Exposed Image Pair

    Directory of Open Access Journals (Sweden)

    Won-Jae Park

    2017-06-01

    Full Text Available In this paper, a high dynamic range (HDR imaging method based on the stereo vision system is presented. The proposed method uses differently exposed low dynamic range (LDR images captured from a stereo camera. The stereo LDR images are first converted to initial stereo HDR images using the inverse camera response function estimated from the LDR images. However, due to the limited dynamic range of the stereo LDR camera, the radiance values in under/over-exposed regions of the initial main-view (MV HDR image can be lost. To restore these radiance values, the proposed stereo matching and hole-filling algorithms are applied to the stereo HDR images. Specifically, the auxiliary-view (AV HDR image is warped by using the estimated disparity between initial the stereo HDR images and then effective hole-filling is applied to the warped AV HDR image. To reconstruct the final MV HDR, the warped and hole-filled AV HDR image is fused with the initial MV HDR image using the weight map. The experimental results demonstrate objectively and subjectively that the proposed stereo HDR imaging method provides better performance compared to the conventional method.

  11. Time Series Analysis of Insar Data: Methods and Trends

    Science.gov (United States)

    Osmanoglu, Batuhan; Sunar, Filiz; Wdowinski, Shimon; Cano-Cabral, Enrique

    2015-01-01

    Time series analysis of InSAR data has emerged as an important tool for monitoring and measuring the displacement of the Earth's surface. Changes in the Earth's surface can result from a wide range of phenomena such as earthquakes, volcanoes, landslides, variations in ground water levels, and changes in wetland water levels. Time series analysis is applied to interferometric phase measurements, which wrap around when the observed motion is larger than one-half of the radar wavelength. Thus, the spatio-temporal ''unwrapping" of phase observations is necessary to obtain physically meaningful results. Several different algorithms have been developed for time series analysis of InSAR data to solve for this ambiguity. These algorithms may employ different models for time series analysis, but they all generate a first-order deformation rate, which can be compared to each other. However, there is no single algorithm that can provide optimal results in all cases. Since time series analyses of InSAR data are used in a variety of applications with different characteristics, each algorithm possesses inherently unique strengths and weaknesses. In this review article, following a brief overview of InSAR technology, we discuss several algorithms developed for time series analysis of InSAR data using an example set of results for measuring subsidence rates in Mexico City.

  12. Usefulness of dynamic magnetic resonance imaging in brain tumors

    International Nuclear Information System (INIS)

    Joo, Yang Gu; Suh, Soo Jhi; Zeon, Seok Kil; Woo, Sung Ku; Kim, Hong; Kim, Jung Sik; Lee, Sung Moon; Lee, Hee Jung; Takahashi, Mutsumasa

    1994-01-01

    To investigate the usefulness of dynamic MR imaging in the differential diagnosis of brain tumors. Dynamic MR imaging was performed in 43 patients with histopathologically proved brain tumors. Serial images were sequentially obtained every 30 seconds for 3-5 minutes with use of spin-echo technique(TR 200msec/TE 15msec) after rapid injection of Gd-DTPA in a dose of 0.1mmol/kg body weight. Dynamics of contrast enhancement of the brain tumors were analyzed visually and by the sequential contrast enhancement ratio(CER). On the dynamic MR imaging, contrast enhancement pattern of the gliomas showed gradual increase in signal intensity(SI) till 180 seconds and usually had a longer time to peak of the CER. The SI of metastatic brain tumors increased steeply till 30 seconds and then rapidly or gradually decreased and the tumors had a shorter time to peak of the CER. Meningiomas showed a rapid ascent in SI till 30 to 60 seconds and then made a plateau or slight descent of the CER. Lymphomas and germinomas showed relatively rapid increase of SI till 30 seconds and usually had a longer time peak of the CER. Dynamic MR imaging with Gd-DTPA may lead to further information about the brain tumors as the sequential contrast enhancement pattern and CER parameters seem to be helpful in discriminating among the brain tumors

  13. Increasing the Dynamic Range of Synthetic Aperture Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2014-01-01

    images. The emissions for the two imaging modes are interleaved 1-to-1 ratio, providing a high frame rate equal to the effective pulse repetition frequency of each imaging mode. The direction of the flow is estimated, and the velocity is then determined in that direction. This method Works for all angles...... standard deviations are 1.59% and 6.12%, respectively. The presented method can improve the estimates by synthesizing a lower pulse repetition frequency, thereby increasing the dynamic range of the vector velocity imaging....

  14. Fundamentals of quantitative dynamic contrast-enhanced MR imaging.

    Science.gov (United States)

    Paldino, Michael J; Barboriak, Daniel P

    2009-05-01

    Quantitative analysis of dynamic contrast-enhanced MR imaging (DCE-MR imaging) has the power to provide information regarding physiologic characteristics of the microvasculature and is, therefore, of great potential value to the practice of oncology. In particular, these techniques could have a significant impact on the development of novel anticancer therapies as a promising biomarker of drug activity. Standardization of DCE-MR imaging acquisition and analysis to provide more reproducible measures of tumor vessel physiology is of crucial importance to realize this potential. The purpose of this article is to review the pathophysiologic basis and technical aspects of DCE-MR imaging techniques.

  15. The feasibility of magnetic resonance imaging of the dynamic swallowing

    International Nuclear Information System (INIS)

    Yang Jingquan; Gao Mingyong; Luo Suling; Lu Ruiliang; He Xiaohong

    2012-01-01

    Objective: To offer some visual and valuable clinical bases for the pharynx disease diagnosis and treatment by comparing the influence of different scanning sequences on the image quality and scanning time, and studying the application to the dynamic swallowing MRI scanning. Methods: The dynamic swallowing scanning of pharyngeal was performed on 20 nasopharyngeal carcinoma patients without deglutition disorders through GE 3.0 MRI system with fast imaging employing steady state acquisition (FIESTA) and fast gradient recalled echo (Fast GRE) sequences, and combined with the array spatial sensitivity encoding technique (ASSET), which accelerating factors was 2.0 ph, and sixty dynamic images were acquired sequentially. The image quality was graded into three classes:excellent, favorable and poor,which were visually assessed by three senior MRI physician using double-blinded method. The quantitative data were analyzed statistically with the SPSS13.0 software. Results: Under the same parameters,the scanning time with FIESTA, FIESTA+ASSET, Fast GRE and Fast GREA+ASSET sequences were 54 s, 28 s, 49 s and 25 s respectively. The number of excellent images with the four sequences were 44, 52, 52 and 56 respectively. The scanning time was the shortest and the image quality was the best with Fast GRE+ASSET sequence. Conclusions: The dynamic imaging of swallowing in sagittal view was achieved with Fast GRE+ASSET sequence on GE 3.0T MRI system. It could present status of the pharynx well, and the soft tissue of swallowing was showed clearly in the dynamic images. These will provide visual and effective evidence for clinical diagnosis and treatment. (authors)

  16. Dynamic PET Image reconstruction for parametric imaging using the HYPR kernel method

    Science.gov (United States)

    Spencer, Benjamin; Qi, Jinyi; Badawi, Ramsey D.; Wang, Guobao

    2017-03-01

    Dynamic PET image reconstruction is a challenging problem because of the ill-conditioned nature of PET and the lowcounting statistics resulted from short time-frames in dynamic imaging. The kernel method for image reconstruction has been developed to improve image reconstruction of low-count PET data by incorporating prior information derived from high-count composite data. In contrast to most of the existing regularization-based methods, the kernel method embeds image prior information in the forward projection model and does not require an explicit regularization term in the reconstruction formula. Inspired by the existing highly constrained back-projection (HYPR) algorithm for dynamic PET image denoising, we propose in this work a new type of kernel that is simpler to implement and further improves the kernel-based dynamic PET image reconstruction. Our evaluation study using a physical phantom scan with synthetic FDG tracer kinetics has demonstrated that the new HYPR kernel-based reconstruction can achieve a better region-of-interest (ROI) bias versus standard deviation trade-off for dynamic PET parametric imaging than the post-reconstruction HYPR denoising method and the previously used nonlocal-means kernel.

  17. Ship dynamics for maritime ISAR imaging.

    Energy Technology Data Exchange (ETDEWEB)

    Doerry, Armin Walter

    2008-02-01

    Demand is increasing for imaging ships at sea. Conventional SAR fails because the ships are usually in motion, both with a forward velocity, and other linear and angular motions that accompany sea travel. Because the target itself is moving, this becomes an Inverse- SAR, or ISAR problem. Developing useful ISAR techniques and algorithms is considerably aided by first understanding the nature and characteristics of ship motion. Consequently, a brief study of some principles of naval architecture sheds useful light on this problem. We attempt to do so here. Ship motions are analyzed for their impact on range-Doppler imaging using Inverse Synthetic Aperture Radar (ISAR). A framework for analysis is developed, and limitations of simple ISAR systems are discussed.

  18. Software for Generating Troposphere Corrections for InSAR Using GPS and Weather Model Data

    Science.gov (United States)

    Moore, Angelyn W.; Webb, Frank H.; Fishbein, Evan F.; Fielding, Eric J.; Owen, Susan E.; Granger, Stephanie L.; Bjoerndahl, Fredrik; Loefgren, Johan; Fang, Peng; Means, James D.; hide

    2013-01-01

    Atmospheric errors due to the troposphere are a limiting error source for spaceborne interferometric synthetic aperture radar (InSAR) imaging. This software generates tropospheric delay maps that can be used to correct atmospheric artifacts in InSAR data. The software automatically acquires all needed GPS (Global Positioning System), weather, and Digital Elevation Map data, and generates a tropospheric correction map using a novel algorithm for combining GPS and weather information while accounting for terrain. Existing JPL software was prototypical in nature, required a MATLAB license, required additional steps to acquire and ingest needed GPS and weather data, and did not account for topography in interpolation. Previous software did not achieve a level of automation suitable for integration in a Web portal. This software overcomes these issues. GPS estimates of tropospheric delay are a source of corrections that can be used to form correction maps to be applied to InSAR data, but the spacing of GPS stations is insufficient to remove short-wavelength tropospheric artifacts. This software combines interpolated GPS delay with weather model precipitable water vapor (PWV) and a digital elevation model to account for terrain, increasing the spatial resolution of the tropospheric correction maps and thus removing short wavelength tropospheric artifacts to a greater extent. It will be integrated into a Web portal request system, allowing use in a future L-band SAR Earth radar mission data system. This will be a significant contribution to its technology readiness, building on existing investments in in situ space geodetic networks, and improving timeliness, quality, and science value of the collected data

  19. Electrophysiological Source Imaging: A Noninvasive Window to Brain Dynamics.

    Science.gov (United States)

    He, Bin; Sohrabpour, Abbas; Brown, Emery; Liu, Zhongming

    2018-06-04

    Brain activity and connectivity are distributed in the three-dimensional space and evolve in time. It is important to image brain dynamics with high spatial and temporal resolution. Electroencephalography (EEG) and magnetoencephalography (MEG) are noninvasive measurements associated with complex neural activations and interactions that encode brain functions. Electrophysiological source imaging estimates the underlying brain electrical sources from EEG and MEG measurements. It offers increasingly improved spatial resolution and intrinsically high temporal resolution for imaging large-scale brain activity and connectivity on a wide range of timescales. Integration of electrophysiological source imaging and functional magnetic resonance imaging could further enhance spatiotemporal resolution and specificity to an extent that is not attainable with either technique alone. We review methodological developments in electrophysiological source imaging over the past three decades and envision its future advancement into a powerful functional neuroimaging technology for basic and clinical neuroscience applications.

  20. High-dynamic-range imaging for cloud segmentation

    Science.gov (United States)

    Dev, Soumyabrata; Savoy, Florian M.; Lee, Yee Hui; Winkler, Stefan

    2018-04-01

    Sky-cloud images obtained from ground-based sky cameras are usually captured using a fisheye lens with a wide field of view. However, the sky exhibits a large dynamic range in terms of luminance, more than a conventional camera can capture. It is thus difficult to capture the details of an entire scene with a regular camera in a single shot. In most cases, the circumsolar region is overexposed, and the regions near the horizon are underexposed. This renders cloud segmentation for such images difficult. In this paper, we propose HDRCloudSeg - an effective method for cloud segmentation using high-dynamic-range (HDR) imaging based on multi-exposure fusion. We describe the HDR image generation process and release a new database to the community for benchmarking. Our proposed approach is the first using HDR radiance maps for cloud segmentation and achieves very good results.

  1. Contour junctions defined by dynamic image deformations enhance perceptual transparency.

    Science.gov (United States)

    Kawabe, Takahiro; Nishida, Shin'ya

    2017-11-01

    The majority of work on the perception of transparency has focused on static images with luminance-defined contour junctions, but recent work has shown that dynamic image sequences with dynamic image deformations also provide information about transparency. The present study demonstrates that when part of a static image is dynamically deformed, contour junctions at which deforming and nondeforming contours are connected facilitate the deformation-based perception of a transparent layer. We found that the impression of a transparent layer was stronger when a dynamically deforming area was adjacent to static nondeforming areas than when presented alone. When contour junctions were not formed at the dynamic-static boundaries, however, the impression of a transparent layer was not facilitated by the presence of static surrounding areas. The effect of the deformation-defined junctions was attenuated when the spatial pattern of luminance contrast at the junctions was inconsistent with the perceived transparency related to luminance contrast, while the effect did not change when the spatial luminance pattern was consistent with it. In addition, the results showed that contour completions across the junctions were required for the perception of a transparent layer. These results indicate that deformation-defined junctions that involve contour completion between deforming and nondeforming regions enhance the perception of a transparent layer, and that the deformation-based perceptual transparency can be promoted by the simultaneous presence of appropriately configured luminance and contrast-other features that can also by themselves produce the sensation of perceiving transparency.

  2. Research on hyperspectral dynamic scene and image sequence simulation

    Science.gov (United States)

    Sun, Dandan; Liu, Fang; Gao, Jiaobo; Sun, Kefeng; Hu, Yu; Li, Yu; Xie, Junhu; Zhang, Lei

    2016-10-01

    This paper presents a simulation method of hyperspectral dynamic scene and image sequence for hyperspectral equipment evaluation and target detection algorithm. Because of high spectral resolution, strong band continuity, anti-interference and other advantages, in recent years, hyperspectral imaging technology has been rapidly developed and is widely used in many areas such as optoelectronic target detection, military defense and remote sensing systems. Digital imaging simulation, as a crucial part of hardware in loop simulation, can be applied to testing and evaluation hyperspectral imaging equipment with lower development cost and shorter development period. Meanwhile, visual simulation can produce a lot of original image data under various conditions for hyperspectral image feature extraction and classification algorithm. Based on radiation physic model and material characteristic parameters this paper proposes a generation method of digital scene. By building multiple sensor models under different bands and different bandwidths, hyperspectral scenes in visible, MWIR, LWIR band, with spectral resolution 0.01μm, 0.05μm and 0.1μm have been simulated in this paper. The final dynamic scenes have high real-time and realistic, with frequency up to 100 HZ. By means of saving all the scene gray data in the same viewpoint image sequence is obtained. The analysis results show whether in the infrared band or the visible band, the grayscale variations of simulated hyperspectral images are consistent with the theoretical analysis results.

  3. A Novel Image Stream Cipher Based On Dynamic Substitution

    OpenAIRE

    Elsharkawi, A.; El-Sagheer, R. M.; Akah, H.; Taha, H.

    2016-01-01

    Recently, many chaos-based stream cipher algorithms have been developed. Traditional chaos stream cipher is based on XORing a generated secure random number sequence based on chaotic maps (e.g. logistic map, Bernoulli Map, Tent Map etc.) with the original image to get the encrypted image, This type of stream cipher seems to be vulnerable to chosen plaintext attacks. This paper introduces a new stream cipher algorithm based on dynamic substitution box. The new algorithm uses one substitution b...

  4. INVESTIGATION OF LITHOSPHERIC STRUCTURE IN MONGOLIA: INSIGHTS FROM INSAR OBSERVATIONS AND MODELLING

    Directory of Open Access Journals (Sweden)

    Z. Jing

    2017-09-01

    Full Text Available The western Mongolia is a seismically active intracontinental region, with ongoing tectonic deformation and widespread seismicity related to the far-field effects of India-Eurasia collision. During the 20th century, four earthquakes with the magnitude larger than 8 occurred in the western Mongolia and its surrounding regions, providing a unique opportunity to study the geodynamics of intracontinental tectonic deformations. The 1957 magnitude 8.3 Gobi-Altai earthquake is one of the largest seismic events. The deformation pattern of rupture zone associated with this earthquake is complex, involving left-lateral strike-slip and reverse dip-slip faulting on several distinct geological structures in a 264 × 40 km wide zone. To understand the relationship between the observed postseismic surface deformation and the rheological structure of the upper lithosphere, Interferometric Synthetic Aperture Radar (InSAR data are used to study the 1957 earthquake. Then we developed a postseismic model in a spherical, radially layered elastic-viscoelastic Earth based on InSAR results, and further analysed the dominant contribution to the surface deformation. This work is important for understanding not only the regional tectonics, but also the structure and dynamics of the lithosphere. SAR data were acquired from the ERS1/2 and Envisat from 1996 to 2010. Using the Repeat Orbit Interferometry Package (ROI_PAC, 124 postseismic interferograms are produced on four adjacent tracks. By stacking these interferograms, the maximum InSAR line-of-sight deformation rate along the Gobi-Altai fault zone is obtained. The main results are as follows: (1 The maximum InSAR line-of-sight deformation velocity along this large fault zone is about 6 mm/yr; (2 The modelled surface deformation suggests that the viscoelastic relaxation is the most reasonable mechanism to explain the observed surface motion; (3 The optimal model cover the Gobi-Altai seismogenic thickness is 10

  5. Elevation Extraction and Deformation Monitoring by Multitemporal InSAR of Lupu Bridge in Shanghai

    Directory of Open Access Journals (Sweden)

    Jingwen Zhao

    2017-08-01

    Full Text Available Monitoring, assessing, and understanding the structural health of large infrastructures, such as buildings, bridges, dams, tunnels, and highways, is important for urban development and management, as the gradual deterioration of such structures may result in catastrophic structural failure leading to high personal and economic losses. With a higher spatial resolution and a shorter revisit period, interferometric synthetic aperture radar (InSAR plays an increasing role in the deformation monitoring and height extraction of structures. As a focal point of the InSAR data processing chain, phase unwrapping has a direct impact on the accuracy of the results. In complex urban areas, large elevation differences between the top and bottom parts of a large structure combined with a long interferometric baseline can result in a serious phase-wrapping problem. Here, with no accurate digital surface model (DSM available, we handle the large phase gradients of arcs in multitemporal InSAR processing using a long–short baseline iteration method. Specifically, groups of interferometric pairs with short baselines are processed to obtain the rough initial elevation estimations of the persistent scatterers (PSs. The baseline threshold is then loosened in subsequent iterations to improve the accuracy of the elevation estimates step by step. The LLL lattice reduction algorithm (by Lenstra, Lenstra, and Lovász is applied in the InSAR phase unwrapping process to rapidly reduce the search radius, compress the search space, and improve the success rate in resolving the phase ambiguities. Once the elevations of the selected PSs are determined, they are used in the following two-dimensional phase regression involving both elevations and deformations. A case study of Lupu Bridge in Shanghai is carried out for the algorithm’s verification. The estimated PS elevations agree well (within 1 m with the official Lupu Bridge model data, while the PS deformation time series

  6. Non-local means denoising of dynamic PET images.

    Directory of Open Access Journals (Sweden)

    Joyita Dutta

    Full Text Available Dynamic positron emission tomography (PET, which reveals information about both the spatial distribution and temporal kinetics of a radiotracer, enables quantitative interpretation of PET data. Model-based interpretation of dynamic PET images by means of parametric fitting, however, is often a challenging task due to high levels of noise, thus necessitating a denoising step. The objective of this paper is to develop and characterize a denoising framework for dynamic PET based on non-local means (NLM.NLM denoising computes weighted averages of voxel intensities assigning larger weights to voxels that are similar to a given voxel in terms of their local neighborhoods or patches. We introduce three key modifications to tailor the original NLM framework to dynamic PET. Firstly, we derive similarities from less noisy later time points in a typical PET acquisition to denoise the entire time series. Secondly, we use spatiotemporal patches for robust similarity computation. Finally, we use a spatially varying smoothing parameter based on a local variance approximation over each spatiotemporal patch.To assess the performance of our denoising technique, we performed a realistic simulation on a dynamic digital phantom based on the Digimouse atlas. For experimental validation, we denoised [Formula: see text] PET images from a mouse study and a hepatocellular carcinoma patient study. We compared the performance of NLM denoising with four other denoising approaches - Gaussian filtering, PCA, HYPR, and conventional NLM based on spatial patches.The simulation study revealed significant improvement in bias-variance performance achieved using our NLM technique relative to all the other methods. The experimental data analysis revealed that our technique leads to clear improvement in contrast-to-noise ratio in Patlak parametric images generated from denoised preclinical and clinical dynamic images, indicating its ability to preserve image contrast and high

  7. Non-local means denoising of dynamic PET images.

    Science.gov (United States)

    Dutta, Joyita; Leahy, Richard M; Li, Quanzheng

    2013-01-01

    Dynamic positron emission tomography (PET), which reveals information about both the spatial distribution and temporal kinetics of a radiotracer, enables quantitative interpretation of PET data. Model-based interpretation of dynamic PET images by means of parametric fitting, however, is often a challenging task due to high levels of noise, thus necessitating a denoising step. The objective of this paper is to develop and characterize a denoising framework for dynamic PET based on non-local means (NLM). NLM denoising computes weighted averages of voxel intensities assigning larger weights to voxels that are similar to a given voxel in terms of their local neighborhoods or patches. We introduce three key modifications to tailor the original NLM framework to dynamic PET. Firstly, we derive similarities from less noisy later time points in a typical PET acquisition to denoise the entire time series. Secondly, we use spatiotemporal patches for robust similarity computation. Finally, we use a spatially varying smoothing parameter based on a local variance approximation over each spatiotemporal patch. To assess the performance of our denoising technique, we performed a realistic simulation on a dynamic digital phantom based on the Digimouse atlas. For experimental validation, we denoised [Formula: see text] PET images from a mouse study and a hepatocellular carcinoma patient study. We compared the performance of NLM denoising with four other denoising approaches - Gaussian filtering, PCA, HYPR, and conventional NLM based on spatial patches. The simulation study revealed significant improvement in bias-variance performance achieved using our NLM technique relative to all the other methods. The experimental data analysis revealed that our technique leads to clear improvement in contrast-to-noise ratio in Patlak parametric images generated from denoised preclinical and clinical dynamic images, indicating its ability to preserve image contrast and high intensity details while

  8. Accelerated dynamic EPR imaging using fast acquisition and compressive recovery.

    Science.gov (United States)

    Ahmad, Rizwan; Samouilov, Alexandre; Zweier, Jay L

    2016-12-01

    Electron paramagnetic resonance (EPR) allows quantitative imaging of tissue redox status, which provides important information about ischemic syndromes, cancer and other pathologies. For continuous wave EPR imaging, however, poor signal-to-noise ratio and low acquisition efficiency limit its ability to image dynamic processes in vivo including tissue redox, where conditions can change rapidly. Here, we present a data acquisition and processing framework that couples fast acquisition with compressive sensing-inspired image recovery to enable EPR-based redox imaging with high spatial and temporal resolutions. The fast acquisition (FA) allows collecting more, albeit noisier, projections in a given scan time. The composite regularization based processing method, called spatio-temporal adaptive recovery (STAR), not only exploits sparsity in multiple representations of the spatio-temporal image but also adaptively adjusts the regularization strength for each representation based on its inherent level of the sparsity. As a result, STAR adjusts to the disparity in the level of sparsity across multiple representations, without introducing any tuning parameter. Our simulation and phantom imaging studies indicate that a combination of fast acquisition and STAR (FASTAR) enables high-fidelity recovery of volumetric image series, with each volumetric image employing less than 10 s of scan. In addition to image fidelity, the time constants derived from FASTAR also match closely to the ground truth even when a small number of projections are used for recovery. This development will enhance the capability of EPR to study fast dynamic processes that cannot be investigated using existing EPR imaging techniques. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. Valuation of dynamic MR imaging for diagnosis of pituitary microadenomas

    International Nuclear Information System (INIS)

    Lu Wu; Zhou Shengli; Liu Yusheng

    2003-01-01

    Objective: To evaluate the use of keyhole dynamic magnetic resonance (MR) imaging in evaluation of pituitary microadenomas. Methods: Fifty-three patients with pituitary microadenomas proved by operation or clinical findings such as headache, amenorrhea, lactating, fat or acromegaly were retrospectively studied on dynamic MR, conventional contrast enhanced MR, and unenhanced MR. Then the image data were analyzed by two experienced doctors who didn't know the details and three degrees were made as follows: grade 0, no evidence of the tumor; grade I, asymmetry signals in the pituitary; and grade II, nodulated or sheets signals in the pituitary. The grading data were compared with statistical methods. Results: In dynamic MR grading system: grade 0 was revealed in 1 patient, grade I in 29 patients and grade II in 23 patients. In conventional enhanced MR: grade 0 in 26 patients, grade I in 17 patients and grade II in 10 patients. In conventional unenhanced MR: grade 0 in 39 patients, grade I in 10 patients and grade II in 4 patients. The diagnostic rate of dynamic MR, conventional enhanced MR, and unenhanced MR was 98.1%, 51.9%, and 26.4%, respectively. (P < 0.005). Dynamic MR can increase the grade of tumor compared to the other two, which is significant statistically. Conclusion: Keyhole dynamic MR can increase the diagnostic accuracy of pituitary microadenomas while decreasing the uncertainty. So dynamic MR should become a routine examination for pituitary microadenoma when suspected by clinical findings but negative in conventional MR

  10. Subtraction and dynamic MR images of breast cancer

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Yoshitaka; Aoki, Manabu; Harada, Junta (Jikei Univ., Tokyo (Japan). School of Medicine)

    1993-04-01

    The purpose of this study was to evaluate the diagnostic effectiveness of subtraction and dynamic MR imaging in patients with breast masses. In 23 breast cancers and six fibroadenomas, spin echo T1 images were obtained at 0.2 Tesla before and every minute after intravenous injection of Gd-DTPA (0.1 or 0.2 mmol/kg). Subtraction images were obtained sequentially on the CRT monitor. All breast masses were enhanced after gadolinium and stood out as bright lesions on subtraction images. The tumor margin and its extension were more precisely evaluated on subtraction MR images than on conventional postcontrast MR images. Breast cancer showed a characteristic time-intensity curve with an early peak, in contrast to fibroadenoma, which showed a gradual increase in signal intensity. Subtraction MR imaging is a simple method for the evaluation of breast masses, and further, the time-intensity curve obtained by dynamic study is helpful in the differential diagnosis of lesions. (author).

  11. Towards imaging of ultrafast molecular dynamics using FELs

    NARCIS (Netherlands)

    Rouzee, A.; Johnsson, P.; Rading, L.; Siu, W.; Huismans, Y.; Duesterer, S.; Redlin, H.; Tavella, F.; Stojanovic, N.; Al-Shemmary, A.; Lepine, F.; Holland, D. M. P.; Schlathölter, Thomas; Hoekstra, R.; Fukuzawa, H.; Ueda, K.; Vrakking, M. J. J.; Hundertmark, A.

    2013-01-01

    The dissociation dynamics induced by a 100 fs, 400 nm laser pulse in a rotationally cold Br-2 sample was characterized by Coulomb explosion imaging (CEI) using a time-delayed extreme ultra-violet (XUV) FEL pulse, obtained from the Free electron LASer in Hamburg (FLASH). The momentum distribution of

  12. Salivary gland masses. Dynamic MR imaging and pathologic correlation

    International Nuclear Information System (INIS)

    Park, Jinho; Inoue, Shingo; Ishizuka, Yasuhito; Shindo, Hiroaki; Kawanishi, Masayuki; Kakizaki, Dai; Abe, Kimihiko; Ebihara, Yoshiro

    1997-01-01

    To evaluate the efficiency of dynamic contrast-enhanced magnetic resonance imaging (MRI) for the diagnosis of salivary gland masses. We retrospectively examined 19 salivary gland masses that were pathologically diagnosed by surgical operation or biopsy. We obtained T1- and T2-weighted images on MRI, performed dynamic studies on each mass and examined the correlation between enhancement patterns and pathological findings. Four enhancement patterns were recognized on contrast-enhanced MRI: type 1 showed marked, homogeneous enhancement; type 2 slights, homogeneous enhancement; type 3 marginal enhancement; and type 4 poor enhancement of the mass. Most pleomorphic adenomas had a type 1 enhancement pattern, but two had a type 2 pattern. Pathologically, each mass enhancement pattern had different tumor cell and matrix components. Warthin's tumor generally showed the type 4 pattern. Primary malignant tumors of the salivary gland all showed the type 3 pattern, and pathological specimens showed many tumor cells along the marginal portion of the tumor. One inflammatory cyst and one Warthin's tumor also showed the type 3 pattern. Except for metastatic renal cell carcinoma, the enhancement patterns of late phase images and dynamic study images were the same. Dynamic MRI added little diagnostic information about salivary gland masses, but the contrast-enhanced MR features correlated well with the pathological findings. (author)

  13. Dynamics of hemispheric dominance for language assessed by magnetoencephalographic imaging.

    Science.gov (United States)

    Findlay, Anne M; Ambrose, Josiah B; Cahn-Weiner, Deborah A; Houde, John F; Honma, Susanne; Hinkley, Leighton B N; Berger, Mitchel S; Nagarajan, Srikantan S; Kirsch, Heidi E

    2012-05-01

    The goal of the current study was to examine the dynamics of language lateralization using magnetoencephalographic (MEG) imaging, to determine the sensitivity and specificity of MEG imaging, and to determine whether MEG imaging can become a viable alternative to the intracarotid amobarbital procedure (IAP), the current gold standard for preoperative language lateralization in neurosurgical candidates. MEG was recorded during an auditory verb generation task and imaging analysis of oscillatory activity was initially performed in 21 subjects with epilepsy, brain tumor, or arteriovenous malformation who had undergone IAP and MEG. Time windows and brain regions of interest that best discriminated between IAP-determined left or right dominance for language were identified. Parameters derived in the retrospective analysis were applied to a prospective cohort of 14 patients and healthy controls. Power decreases in the beta frequency band were consistently observed following auditory stimulation in inferior frontal, superior temporal, and parietal cortices; similar power decreases were also seen in inferior frontal cortex prior to and during overt verb generation. Language lateralization was clearly observed to be a dynamic process that is bilateral for several hundred milliseconds during periods of auditory perception and overt speech production. Correlation with the IAP was seen in 13 of 14 (93%) prospective patients, with the test demonstrating a sensitivity of 100% and specificity of 92%. Our results demonstrate excellent correlation between MEG imaging findings and the IAP for language lateralization, and provide new insights into the spatiotemporal dynamics of cortical speech processing. Copyright © 2012 American Neurological Association.

  14. Spatio-temporal diffusion of dynamic PET images

    International Nuclear Information System (INIS)

    Tauber, C; Chalon, S; Guilloteau, D; Stute, S; Buvat, I; Chau, M; Spiteri, P

    2011-01-01

    Positron emission tomography (PET) images are corrupted by noise. This is especially true in dynamic PET imaging where short frames are required to capture the peak of activity concentration after the radiotracer injection. High noise results in a possible bias in quantification, as the compartmental models used to estimate the kinetic parameters are sensitive to noise. This paper describes a new post-reconstruction filter to increase the signal-to-noise ratio in dynamic PET imaging. It consists in a spatio-temporal robust diffusion of the 4D image based on the time activity curve (TAC) in each voxel. It reduces the noise in homogeneous areas while preserving the distinct kinetics in regions of interest corresponding to different underlying physiological processes. Neither anatomical priors nor the kinetic model are required. We propose an automatic selection of the scale parameter involved in the diffusion process based on a robust statistical analysis of the distances between TACs. The method is evaluated using Monte Carlo simulations of brain activity distributions. We demonstrate the usefulness of the method and its superior performance over two other post-reconstruction spatial and temporal filters. Our simulations suggest that the proposed method can be used to significantly increase the signal-to-noise ratio in dynamic PET imaging.

  15. Developments in Dynamic Analysis for quantitative PIXE true elemental imaging

    International Nuclear Information System (INIS)

    Ryan, C.G.

    2001-01-01

    Dynamic Analysis (DA) is a method for projecting quantitative major and trace element images from PIXE event data-streams (off-line or on-line) obtained using the Nuclear Microprobe. The method separates full elemental spectral signatures to produce images that strongly reject artifacts due to overlapping elements, detector effects (such as escape peaks and tailing) and background. The images are also quantitative, stored in ppm-charge units, enabling images to be directly interrogated for the concentrations of all elements in areas of the images. Recent advances in the method include the correction for changing X-ray yields due to varying sample compositions across the image area and the construction of statistical variance images. The resulting accuracy of major element concentrations extracted directly from these images is better than 3% relative as determined from comparisons with electron microprobe point analysis. These results are complemented by error estimates derived from the variance images together with detection limits. This paper provides an update of research on these issues, introduces new software designed to make DA more accessible, and illustrates the application of the method to selected geological problems.

  16. Post-Eruptive Inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014

    Directory of Open Access Journals (Sweden)

    Feifei Qu

    2015-12-01

    Full Text Available Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July–August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48–130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the six years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

  17. Post-eruptive inflation of Okmok Volcano, Alaska, from InSAR, 2008–2014

    Science.gov (United States)

    Qu, Feifei; Lu, Zhong; Poland, Michael; Freymueller, Jeffrey T.; Zhang, Qin; Jung, Hyung-Sup

    2016-01-01

    Okmok, a ~10-km wide caldera that occupies most of the northeastern end of Umnak Island, is one of the most active volcanoes in the Aleutian arc. The most recent eruption at Okmok during July-August 2008 was by far its largest and most explosive since at least the early 19th century. We investigate post-eruptive magma supply and storage at the volcano during 2008–2014 by analyzing all available synthetic aperture radar (SAR) images of Okmok acquired during that time period using the multi-temporal InSAR technique. Data from the C-band Envisat and X-band TerraSAR-X satellites indicate that Okmok started inflating very soon after the end of 2008 eruption at a time-variable rate of 48-130 mm/y, consistent with GPS measurements. The “model-assisted” phase unwrapping method is applied to improve the phase unwrapping operation for long temporal baseline pairs. The InSAR time-series is used as input for deformation source modeling, which suggests magma accumulating at variable rates in a shallow storage zone at ~3.9 km below sea level beneath the summit caldera, consistent with previous studies. The modeled volume accumulation in the 6 years following the 2008 eruption is ~75% of the 1997 eruption volume and ~25% of the 2008 eruption volume.

  18. ATMOSPHERIC PHASE DELAY CORRECTION OF D-INSAR BASED ON SENTINEL-1A

    Directory of Open Access Journals (Sweden)

    X. Li

    2018-04-01

    Full Text Available In this paper, we used the Generic Atmospheric Correction Online Service for InSAR (GACOS tropospheric delay maps to correct the atmospheric phase delay of the differential interferometric synthetic aperture radar (D-InSAR monitoring, and we improved the accuracy of subsidence monitoring using D-InSAR technology. Atmospheric phase delay, as one of the most important errors that limit the monitoring accuracy of InSAR, would lead to the masking of true phase in subsidence monitoring. For the problem, this paper used the Sentinel-1A images and the tropospheric delay maps got from GACOS to monitor the subsidence of the Yellow River Delta in Shandong Province. The conventional D-InSAR processing was performed using the GAMMA software. The MATLAB codes were used to correct the atmospheric delay of the D-InSAR results. The results before and after the atmospheric phase delay correction were verified and analyzed in the main subsidence area. The experimental results show that atmospheric phase influences the deformation results to a certain extent. After the correction, the measurement error of vertical deformation is reduced by about 18 mm, which proves that the removal of atmospheric effects can improve the accuracy of the D-InSAR monitoring.

  19. Integrated analysis of PALSAR/Radarsat-1 InSAR and ENVISAT altimeter data for mapping of absolute water level changes in Louisiana wetlands

    Science.gov (United States)

    Kim, J.-W.; Lu, Z.; Lee, H.; Shum, C.K.; Swarzenski, C.M.; Doyle, T.W.; Baek, S.-H.

    2009-01-01

    Interferometric Synthetic Aperture Radar (InSAR) has been used to detect relative water level changes in wetlands. We developed an innovative method to integrate InSAR and satellite radar altimetry for measuring absolute or geocentric water level changes and applied the methodology to remote areas of swamp forest in coastal Louisiana. Coherence analysis of InSAR pairs suggested that the HH polarization is preferred for this type of observation, and polarimetric analysis can help to identify double-bounce backscattering areas in the wetland. ENVISAT radar altimeter-measured 18-Hz (along-track sampling of 417 m) water level data processed with regional stackfile method have been used to provide vertical references for water bodies separated by levees. The high-resolution (~ 40 m) relative water changes measured from ALOS PALSAR L-band and Radarsat-1 C-band InSAR are then integrated with ENVISAT radar altimetry to obtain absolute water level. The resulting water level time series were validated with in situ gauge observations within the swamp forest. We anticipate that this new technique will allow retrospective reconstruction and concurrent monitoring of water conditions and flow dynamics in wetlands, especially those lacking gauge networks.

  20. SIMA: Python software for analysis of dynamic fluorescence imaging data

    Directory of Open Access Journals (Sweden)

    Patrick eKaifosh

    2014-09-01

    Full Text Available Fluorescence imaging is a powerful method for monitoring dynamic signals in the nervous system. However, analysis of dynamic fluorescence imaging data remains burdensome, in part due to the shortage of available software tools. To address this need, we have developed SIMA, an open source Python package that facilitates common analysis tasks related to fluorescence imaging. Functionality of this package includes correction of motion artifacts occurring during in vivo imaging with laser-scanning microscopy, segmentation of imaged fields into regions of interest (ROIs, and extraction of signals from the segmented ROIs. We have also developed a graphical user interface (GUI for manual editing of the automatically segmented ROIs and automated registration of ROIs across multiple imaging datasets. This software has been designed with flexibility in mind to allow for future extension with different analysis methods and potential integration with other packages. Software, documentation, and source code for the SIMA package and ROI Buddy GUI are freely available at http://www.losonczylab.org/sima/.

  1. Dynamic Raman imaging system with high spatial and temporal resolution

    Science.gov (United States)

    Wang, Lei; Dai, Yinzhen; He, Hao; Lv, Ruiqi; Zong, Cheng; Ren, Bin

    2017-09-01

    There is an increasing need to study dynamic changing systems with significantly high spatial and temporal resolutions. In this work, we integrated point-scanning, line-scanning, and wide-field Raman imaging techniques into a single system. By using an Electron Multiplying CCD (EMCCD) with a high gain and high frame rate, we significantly reduced the time required for wide-field imaging, making it possible to monitor the electrochemical reactions in situ. The highest frame rate of EMCDD was ˜50 fps, and the Raman images for a specific Raman peak can be obtained by passing the signal from the sample through the Liquid Crystal Tunable Filter. The spatial resolutions of scanning imaging and wide-field imaging with a 100× objective (NA = 0.9) are 0.5 × 0.5 μm2 and 0.36 × 0.36 μm2, respectively. The system was used to study the surface plasmon resonance of Au nanorods, the surface-enhanced Raman scattering signal distribution for Au Nanoparticle aggregates, and dynamic Raman imaging of an electrochemical reacting system.

  2. Imaging of aortic valve dynamics in 4D OCT

    Directory of Open Access Journals (Sweden)

    Schnabel Christian

    2015-09-01

    Full Text Available The mechanical components of the heart, especially the valves and leaflets, are enormous stressed during lifetime. Therefore, those structures undergo different pathophysiological tissue transformations which affect cardiac output and in consequence living comfort of affected patients. These changes may lead to calcific aortic valve stenosis (AVS, the major heart valve disease in humans. The knowledge about changes of the dynamic behaviour during the course of this disease and the possibility of early stage diagnosis is of particular interest and could lead to the development of new treatment strategies and drug based options of prevention or therapy. 4D optical coherence tomography (OCT in combination with high-speed video microscopy were applied to characterize dynamic behaviour of the murine aortic valve and to characterize dynamic properties during artificial stimulation. We present a promising tool to investigate the aortic valve dynamics in an ex vivo disease model with a high spatial and temporal resolution using a multimodal imaging setup.

  3. Imaging Electron Dynamics with Ultrashort Light Pulses: A Theory Perspective

    Directory of Open Access Journals (Sweden)

    Daria Popova-Gorelova

    2018-02-01

    Full Text Available A wide range of ultrafast phenomena in various atomic, molecular and condense matter systems is governed by electron dynamics. Therefore, the ability to image electronic motion in real space and real time would provide a deeper understanding of such processes and guide developments of tools to control them. Ultrashort light pulses, which can provide unprecedented time resolution approaching subfemtosecond time scale, are perspective to achieve real-time imaging of electron dynamics. This task is challenging not only from an experimental view, but also from a theory perspective, since standard theories describing light-matter interaction in a stationary regime can provide erroneous results in an ultrafast case as demonstrated by several theoretical studies. We review the theoretical framework based on quantum electrodynamics, which has been shown to be necessary for an accurate description of time-resolved imaging of electron dynamics with ultrashort light pulses. We compare the results of theoretical studies of time-resolved nonresonant and resonant X-ray scattering, and time- and angle-resolved photoelectron spectroscopy and show that the corresponding time-resolved signals encode analogous information about electron dynamics. Thereby, the information about an electronic system provided by these time-resolved techniques is different from the information provided by their time-independent analogues.

  4. Kalman filter techniques for accelerated Cartesian dynamic cardiac imaging.

    Science.gov (United States)

    Feng, Xue; Salerno, Michael; Kramer, Christopher M; Meyer, Craig H

    2013-05-01

    In dynamic MRI, spatial and temporal parallel imaging can be exploited to reduce scan time. Real-time reconstruction enables immediate visualization during the scan. Commonly used view-sharing techniques suffer from limited temporal resolution, and many of the more advanced reconstruction methods are either retrospective, time-consuming, or both. A Kalman filter model capable of real-time reconstruction can be used to increase the spatial and temporal resolution in dynamic MRI reconstruction. The original study describing the use of the Kalman filter in dynamic MRI was limited to non-Cartesian trajectories because of a limitation intrinsic to the dynamic model used in that study. Here the limitation is overcome, and the model is applied to the more commonly used Cartesian trajectory with fast reconstruction. Furthermore, a combination of the Kalman filter model with Cartesian parallel imaging is presented to further increase the spatial and temporal resolution and signal-to-noise ratio. Simulations and experiments were conducted to demonstrate that the Kalman filter model can increase the temporal resolution of the image series compared with view-sharing techniques and decrease the spatial aliasing compared with TGRAPPA. The method requires relatively little computation, and thus is suitable for real-time reconstruction. Copyright © 2012 Wiley Periodicals, Inc.

  5. Computational model of lightness perception in high dynamic range imaging

    Science.gov (United States)

    Krawczyk, Grzegorz; Myszkowski, Karol; Seidel, Hans-Peter

    2006-02-01

    An anchoring theory of lightness perception by Gilchrist et al. [1999] explains many characteristics of human visual system such as lightness constancy and its spectacular failures which are important in the perception of images. The principal concept of this theory is the perception of complex scenes in terms of groups of consistent areas (frameworks). Such areas, following the gestalt theorists, are defined by the regions of common illumination. The key aspect of the image perception is the estimation of lightness within each framework through the anchoring to the luminance perceived as white, followed by the computation of the global lightness. In this paper we provide a computational model for automatic decomposition of HDR images into frameworks. We derive a tone mapping operator which predicts lightness perception of the real world scenes and aims at its accurate reproduction on low dynamic range displays. Furthermore, such a decomposition into frameworks opens new grounds for local image analysis in view of human perception.

  6. Non-monotonic behaviour in relaxation dynamics of image restoration

    International Nuclear Information System (INIS)

    Ozeki, Tomoko; Okada, Masato

    2003-01-01

    We have investigated the relaxation dynamics of image restoration through a Bayesian approach. The relaxation dynamics is much faster at zero temperature than at the Nishimori temperature where the pixel-wise error rate is minimized in equilibrium. At low temperature, we observed non-monotonic development of the overlap. We suggest that the optimal performance is realized through premature termination in the relaxation processes in the case of the infinite-range model. We also performed Markov chain Monte Carlo simulations to clarify the underlying mechanism of non-trivial behaviour at low temperature by checking the local field distributions of each pixel

  7. Dynamic Studies of Lung Fluid Clearance with Phase Contrast Imaging

    International Nuclear Information System (INIS)

    Kitchen, Marcus J.; Williams, Ivan; Irvine, Sarah C.; Morgan, Michael J.; Paganin, David M.; Lewis, Rob A.; Pavlov, Konstantin; Hooper, Stuart B.; Wallace, Megan J.; Siu, Karen K. W.; Yagi, Naoto; Uesugi, Kentaro

    2007-01-01

    Clearance of liquid from the airways at birth is a poorly understood process, partly due to the difficulties of observing and measuring the distribution of air within the lung. Imaging dynamic processes within the lung in vivo with high contrast and spatial resolution is therefore a major challenge. However, phase contrast X-ray imaging is able to exploit inhaled air as a contrast agent, rendering the lungs of small animals visible due to the large changes in the refractive index at air/tissue interfaces. In concert with the high spatial resolution afforded by X-ray imaging systems (<100 μm), propagation-based phase contrast imaging is ideal for studying lung development. To this end we have utilized intense, monochromatic synchrotron radiation, together with a fast readout CCD camera, to study fluid clearance from the lungs of rabbit pups at birth. Local rates of fluid clearance have been measured from the dynamic sequences using a single image phase retrieval algorithm

  8. Digital optical tomography system for dynamic breast imaging

    Science.gov (United States)

    Flexman, Molly L.; Khalil, Michael A.; Al Abdi, Rabah; Kim, Hyun K.; Fong, Christopher J.; Desperito, Elise; Hershman, Dawn L.; Barbour, Randall L.; Hielscher, Andreas H.

    2011-07-01

    Diffuse optical tomography has shown promising results as a tool for breast cancer screening and monitoring response to chemotherapy. Dynamic imaging of the transient response of the breast to an external stimulus, such as pressure or a respiratory maneuver, can provide additional information that can be used to detect tumors. We present a new digital continuous-wave optical tomography system designed to simultaneously image both breasts at fast frame rates and with a large number of sources and detectors. The system uses a master-slave digital signal processor-based detection architecture to achieve a dynamic range of 160 dB and a frame rate of 1.7 Hz with 32 sources, 64 detectors, and 4 wavelengths per breast. Included is a preliminary study of one healthy patient and two breast cancer patients showing the ability to identify an invasive carcinoma based on the hemodynamic response to a breath hold.

  9. Hierarchical tone mapping for high dynamic range image visualization

    Science.gov (United States)

    Qiu, Guoping; Duan, Jiang

    2005-07-01

    In this paper, we present a computationally efficient, practically easy to use tone mapping techniques for the visualization of high dynamic range (HDR) images in low dynamic range (LDR) reproduction devices. The new method, termed hierarchical nonlinear linear (HNL) tone-mapping operator maps the pixels in two hierarchical steps. The first step allocates appropriate numbers of LDR display levels to different HDR intensity intervals according to the pixel densities of the intervals. The second step linearly maps the HDR intensity intervals to theirs allocated LDR display levels. In the developed HNL scheme, the assignment of LDR display levels to HDR intensity intervals is controlled by a very simple and flexible formula with a single adjustable parameter. We also show that our new operators can be used for the effective enhancement of ordinary images.

  10. Mining Very High Resolution INSAR Data Based On Complex-GMRF Cues And Relevance Feedback

    Science.gov (United States)

    Singh, Jagmal; Popescu, Anca; Soccorsi, Matteo; Datcu, Mihai

    2012-01-01

    With the increase in number of remote sensing satellites, the number of image-data scenes in our repositories is also increasing and a large quantity of these scenes are never received and used. Thus automatic retrieval of de- sired image-data using query by image content to fully utilize the huge repository volume is becoming of great interest. Generally different users are interested in scenes containing different kind of objects and structures. So its important to analyze all the image information mining (IIM) methods so that its easier for user to select a method depending upon his/her requirement. We concentrate our study only on high-resolution SAR images and we propose to use InSAR observations instead of only one single look complex (SLC) images for mining scenes containing coherent objects such as high-rise buildings. However in case of objects with less coherence like areas with vegetation cover, SLC images exhibits better performance. We demonstrate IIM performance comparison using complex-Gauss Markov Random Fields as texture descriptor for image patches and SVM relevance- feedback.

  11. Femtosecond photodissociation dynamics of I studied by ion imaging

    DEFF Research Database (Denmark)

    Larsen, J.J.; Bjerre, N.; Mørkbak, N.J.

    1998-01-01

    on imaging is employed to analyze the fragments from timed Coulomb explosion studies of femtosecond (fs) molecular dynamics. The technique provides high detection efficiency and direct recording of the two-dimensional velocity of all ionized fragments. We illustrate the approach by studying...... agreement with quantum mechanical wave packet simulations. We discuss the perspectives for extending the studies to photochemical reactions of small polyatomic molecules...

  12. Model Accuracy Comparison for High Resolution Insar Coherence Statistics Over Urban Areas

    Science.gov (United States)

    Zhang, Yue; Fu, Kun; Sun, Xian; Xu, Guangluan; Wang, Hongqi

    2016-06-01

    The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR) images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR) coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.

  13. MODEL ACCURACY COMPARISON FOR HIGH RESOLUTION INSAR COHERENCE STATISTICS OVER URBAN AREAS

    Directory of Open Access Journals (Sweden)

    Y. Zhang

    2016-06-01

    Full Text Available The interferometric coherence map derived from the cross-correlation of two complex registered synthetic aperture radar (SAR images is the reflection of imaged targets. In many applications, it can act as an independent information source, or give additional information complementary to the intensity image. Specially, the statistical properties of the coherence are of great importance in land cover classification, segmentation and change detection. However, compared to the amount of work on the statistical characters of SAR intensity, there are quite fewer researches on interferometric SAR (InSAR coherence statistics. And to our knowledge, all of the existing work that focuses on InSAR coherence statistics, models the coherence with Gaussian distribution with no discrimination on data resolutions or scene types. But the properties of coherence may be different for different data resolutions and scene types. In this paper, we investigate on the coherence statistics for high resolution data over urban areas, by making a comparison of the accuracy of several typical statistical models. Four typical land classes including buildings, trees, shadow and roads are selected as the representatives of urban areas. Firstly, several regions are selected from the coherence map manually and labelled with their corresponding classes respectively. Then we try to model the statistics of the pixel coherence for each type of region, with different models including Gaussian, Rayleigh, Weibull, Beta and Nakagami. Finally, we evaluate the model accuracy for each type of region. The experiments on TanDEM-X data show that the Beta model has a better performance than other distributions.

  14. UAVSAR and TerraSAR-X Based InSAR Detection of Localized Subsidence in the New Orleans Area

    Science.gov (United States)

    Blom, R. G.; An, K.; Jones, C. E.; Latini, D.

    2014-12-01

    Vulnerability of the US Gulf coast to inundation has received increased attention since hurricanes Katrina and Rita. Compounding effects of sea level rise, wetland loss, and regional and local subsidence makes flood protection a difficult challenge, and particularly for the New Orleans area. Key to flood protection is precise knowledge of elevations and elevation changes. Analysis of historical and continuing geodetic measurements show surprising complexity, including locations subsiding more rapidly than considered during planning of hurricane protection and coastal restoration projects. Combining traditional, precise geodetic data with interferometric synthetic aperture radar (InSAR) observations can provide geographically dense constraints on surface deformation. The Gulf Coast environment is challenging for InSAR techniques, especially with systems not designed for interferometry. We use two InSAR capable systems, the L- band (24 cm wavelength) airborne JPL/NASA UAVSAR, and the DLR/EADS Astrium spaceborne TerraSAR X-band (3 cm wavelength), and compare results. First, we are applying pair-wise InSAR to the longer wavelength UAVSAR data to detect localized elevation changes potentially impacting flood protection infrastructure from 2009 - 2014. We focus on areas on and near flood protection infrastructure to identify changes indicative of subsidence, structural deformation, and/or seepage. The Spaceborne TerraSAR X-band SAR system has relatively frequent observations, and dense persistent scatterers in urban areas, enabling measurement of very small displacements. We compare L-band UAVSAR results with permanent scatterer (PS-InSAR) and Short Baseline Subsets (SBAS) interferometric analyses of a stack composed by 28 TerraSAR X-band images acquired over the same period. Thus we can evaluate results from the different radar frequencies and analyses techniques. Preliminary results indicate subsidence features potentially of a variety of causes, including ground water

  15. Tracking ultrafast relaxation dynamics of furan by femtosecond photoelectron imaging

    International Nuclear Information System (INIS)

    Liu, Yuzhu; Knopp, Gregor; Qin, Chaochao; Gerber, Thomas

    2015-01-01

    Graphical abstract: - Highlights: • Relaxation dynamics of furan are tracked by femtosecond photoelectron imaging. • The mechanism for ultrafast formation of α-carbene and β-carbene is proposed. • Ultrafast internal conversion from S 2 to S 1 is observed. • The transient characteristics of the fragment ions are obtained. • Single-color multi-photon ionization dynamics at 800 nm are also studied. - Abstract: Ultrafast internal conversion dynamics of furan has been studied by femtosecond photoelectron imaging (PEI) coupled with photofragmentation (PF) spectroscopy. Photoelectron imaging of single-color multi-photon ionization and two-color pump–probe ionization are obtained and analyzed. Photoelectron bands are assigned to the related states. The time evolution of the photoelectron signal by pump–probe ionization can be well described by a biexponential decay: two rapid relaxation pathways with time constants of ∼15 fs and 85 (±11) fs. The rapid relaxation is ascribed to the ultrafast internal conversion (IC) from the S 2 state to the vibrationally hot S 1 state. The second relaxation process is attributed to the redistributions and depopulation of secondarily populated high vibronic S 1 state and the formation of α-carbene and β-carbene by H immigration. Additionally, the transient characteristics of the fragment ions are also measured and discussed as a complementary understanding

  16. Tracking ultrafast relaxation dynamics of furan by femtosecond photoelectron imaging

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yuzhu, E-mail: yuzhu.liu@gmail.com [School of Physics and Optoelectronic Engineering, Nanjing University of Information Science and Technology, Nanjing 210044 (China); Knopp, Gregor [Paul Scherrer Institute, Villigen 5232 (Switzerland); Qin, Chaochao [Department of Physics, Henan Normal University, Xinxiang 453007 (China); Gerber, Thomas [Paul Scherrer Institute, Villigen 5232 (Switzerland)

    2015-01-13

    Graphical abstract: - Highlights: • Relaxation dynamics of furan are tracked by femtosecond photoelectron imaging. • The mechanism for ultrafast formation of α-carbene and β-carbene is proposed. • Ultrafast internal conversion from S{sub 2} to S{sub 1} is observed. • The transient characteristics of the fragment ions are obtained. • Single-color multi-photon ionization dynamics at 800 nm are also studied. - Abstract: Ultrafast internal conversion dynamics of furan has been studied by femtosecond photoelectron imaging (PEI) coupled with photofragmentation (PF) spectroscopy. Photoelectron imaging of single-color multi-photon ionization and two-color pump–probe ionization are obtained and analyzed. Photoelectron bands are assigned to the related states. The time evolution of the photoelectron signal by pump–probe ionization can be well described by a biexponential decay: two rapid relaxation pathways with time constants of ∼15 fs and 85 (±11) fs. The rapid relaxation is ascribed to the ultrafast internal conversion (IC) from the S{sub 2} state to the vibrationally hot S{sub 1} state. The second relaxation process is attributed to the redistributions and depopulation of secondarily populated high vibronic S{sub 1} state and the formation of α-carbene and β-carbene by H immigration. Additionally, the transient characteristics of the fragment ions are also measured and discussed as a complementary understanding.

  17. Polycystic ovary syndrome: dynamic contrast-enhanced ovary MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Erdem, C. Zuhal E-mail: sunarerdem@yahoo.com; Bayar, Ulku; Erdem, L. Oktay; Barut, Aykut; Gundogdu, Sadi; Kaya, Erdal

    2004-07-01

    Objective: to determine the enhancement behaviour of the ovaries in women with polycystic ovary syndrome (PCOS) by dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging and to compare these data with those of normal ovulating controls. Method: 24 women with PCOS and 12 controls underwent DCE-MR imaging. Dynamic images were acquired before and after injection of a contrast bolus at 30 s and the min of 1, 2, 3, 4 and 5. On postprocessing examination: (i) the ovarian volumes; (ii) the signal intensity value of each ovary per dynamic study; (iii) early-phase enhancement rate; (iv) time to peak enhancement (T{sub p}); and (v) percentage of washout of 5th min were determined. Data of the ovaries of the women with PCOS and controls were compared with Mann-Whitney U-test. Results: the mean values of T{sub p} were found to be significantly lower in women with PCOS than in controls (p<0.05). On the other hand, the mean values of ovarian volume, the early-phase enhancement rate, and percentage of washout of 5th min of ovaries were significantly higher in PCOS patients (p<0.05). Examination of the mean signal intensity-time curve revealed the ovaries in women with PCOS showed a faster and greater enhancement and wash-out. Conclusion: the enhancement behaviour of ovaries of women with PCOS may be significantly different from those of control subjects on DCE-MR imaging examination. In our experience, it is a valuable modality to highlight the vascularization changes in ovarian stroma with PCOS. We believe that improved DCE-MR imaging techniques may also provide us additional parameters in the diagnosis and treatment strategies of PCOS.

  18. Polycystic ovary syndrome: dynamic contrast-enhanced ovary MR imaging

    International Nuclear Information System (INIS)

    Erdem, C. Zuhal; Bayar, Ulku; Erdem, L. Oktay; Barut, Aykut; Gundogdu, Sadi; Kaya, Erdal

    2004-01-01

    Objective: to determine the enhancement behaviour of the ovaries in women with polycystic ovary syndrome (PCOS) by dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging and to compare these data with those of normal ovulating controls. Method: 24 women with PCOS and 12 controls underwent DCE-MR imaging. Dynamic images were acquired before and after injection of a contrast bolus at 30 s and the min of 1, 2, 3, 4 and 5. On postprocessing examination: (i) the ovarian volumes; (ii) the signal intensity value of each ovary per dynamic study; (iii) early-phase enhancement rate; (iv) time to peak enhancement (T p ); and (v) percentage of washout of 5th min were determined. Data of the ovaries of the women with PCOS and controls were compared with Mann-Whitney U-test. Results: the mean values of T p were found to be significantly lower in women with PCOS than in controls (p<0.05). On the other hand, the mean values of ovarian volume, the early-phase enhancement rate, and percentage of washout of 5th min of ovaries were significantly higher in PCOS patients (p<0.05). Examination of the mean signal intensity-time curve revealed the ovaries in women with PCOS showed a faster and greater enhancement and wash-out. Conclusion: the enhancement behaviour of ovaries of women with PCOS may be significantly different from those of control subjects on DCE-MR imaging examination. In our experience, it is a valuable modality to highlight the vascularization changes in ovarian stroma with PCOS. We believe that improved DCE-MR imaging techniques may also provide us additional parameters in the diagnosis and treatment strategies of PCOS

  19. Chaotic Dynamical State Variables Selection Procedure Based Image Encryption Scheme

    Directory of Open Access Journals (Sweden)

    Zia Bashir

    2017-12-01

    Full Text Available Nowadays, in the modern digital era, the use of computer technologies such as smartphones, tablets and the Internet, as well as the enormous quantity of confidential information being converted into digital form have resulted in raised security issues. This, in turn, has led to rapid developments in cryptography, due to the imminent need for system security. Low-dimensional chaotic systems have low complexity and key space, yet they achieve high encryption speed. An image encryption scheme is proposed that, without compromising the security, uses reasonable resources. We introduced a chaotic dynamic state variables selection procedure (CDSVSP to use all state variables of a hyper-chaotic four-dimensional dynamical system. As a result, less iterations of the dynamical system are required, and resources are saved, thus making the algorithm fast and suitable for practical use. The simulation results of security and other miscellaneous tests demonstrate that the suggested algorithm excels at robustness, security and high speed encryption.

  20. POTENTIALS OF IMAGE BASED ACTIVE RANGING TO CAPTURE DYNAMIC SCENES

    Directory of Open Access Journals (Sweden)

    B. Jutzi

    2012-09-01

    Full Text Available Obtaining a 3D description of man-made and natural environments is a basic task in Computer Vision and Remote Sensing. To this end, laser scanning is currently one of the dominating techniques to gather reliable 3D information. The scanning principle inherently needs a certain time interval to acquire the 3D point cloud. On the other hand, new active sensors provide the possibility of capturing range information by images with a single measurement. With this new technique image-based active ranging is possible which allows capturing dynamic scenes, e.g. like walking pedestrians in a yard or moving vehicles. Unfortunately most of these range imaging sensors have strong technical limitations and are not yet sufficient for airborne data acquisition. It can be seen from the recent development of highly specialized (far-range imaging sensors – so called flash-light lasers – that most of the limitations could be alleviated soon, so that future systems will be equipped with improved image size and potentially expanded operating range. The presented work is a first step towards the development of methods capable for application of range images in outdoor environments. To this end, an experimental setup was set up for investigating these proposed possibilities. With the experimental setup a measurement campaign was carried out and first results will be presented within this paper.

  1. Cascaded image analysis for dynamic crack detection in material testing

    Science.gov (United States)

    Hampel, U.; Maas, H.-G.

    Concrete probes in civil engineering material testing often show fissures or hairline-cracks. These cracks develop dynamically. Starting at a width of a few microns, they usually cannot be detected visually or in an image of a camera imaging the whole probe. Conventional image analysis techniques will detect fissures only if they show a width in the order of one pixel. To be able to detect and measure fissures with a width of a fraction of a pixel at an early stage of their development, a cascaded image analysis approach has been developed, implemented and tested. The basic idea of the approach is to detect discontinuities in dense surface deformation vector fields. These deformation vector fields between consecutive stereo image pairs, which are generated by cross correlation or least squares matching, show a precision in the order of 1/50 pixel. Hairline-cracks can be detected and measured by applying edge detection techniques such as a Sobel operator to the results of the image matching process. Cracks will show up as linear discontinuities in the deformation vector field and can be vectorized by edge chaining. In practical tests of the method, cracks with a width of 1/20 pixel could be detected, and their width could be determined at a precision of 1/50 pixel.

  2. An Integrated Tone Mapping for High Dynamic Range Image Visualization

    Science.gov (United States)

    Liang, Lei; Pan, Jeng-Shyang; Zhuang, Yongjun

    2018-01-01

    There are two type tone mapping operators for high dynamic range (HDR) image visualization. HDR image mapped by perceptual operators have strong sense of reality, but will lose local details. Empirical operators can maximize local detail information of HDR image, but realism is not strong. A common tone mapping operator suitable for all applications is not available. This paper proposes a novel integrated tone mapping framework which can achieve conversion between empirical operators and perceptual operators. In this framework, the empirical operator is rendered based on improved saliency map, which simulates the visual attention mechanism of the human eye to the natural scene. The results of objective evaluation prove the effectiveness of the proposed solution.

  3. Global auroral imaging instrumentation for the dynamics explorer mission

    International Nuclear Information System (INIS)

    Frank, L.A.; Craven, J.D.; Ackerson, K.L.; English, M.R.; Eather, R.H.; Carovillano, R.L.

    1981-01-01

    The instrumentation for gaining global images of the auroral oval from the high-altitude spacecraft of the Dynamics Explorer Mission is described. Three spin-scan auroral imaging (SAI) photometers are expected to be able to effectively view the dim emissions from earth in the presence of strong stray light sources near their fields-of-view along the sunlit portion of the spacecraft orbit. A special optical design which includes an off-axis parabolic mirror as the focusing element and super-reflecting mirror surfaces is used to minimize the effects of stray light. The rotation of the spacecraft and an instrument scanning mirror provide the two-dimensional array of pixels comprising an image frame. (orig.)

  4. PIXEL: Japanese InSAR community for crustal deformation research

    Science.gov (United States)

    Furuya, M.; Shimada, M.; Ozawa, T.; Fukushima, Y.; Aoki, Y.; Miyagi, Y.; Kitagawa, S.

    2007-12-01

    In anticipation of the launch of ALOS (Advanced Land Observation Satellite) by JAXA (Japan Aerospace eXploration Agency), and in order to expand and bolster the InSAR community for crustal deformation research in Japan, a couple of scientists established a consortium, PIXEL, in November 2005 in a completely bottom-up fashion. PIXEL stands for Palsar Interferometry Consortium to Study our Evolving Land. Formally, it is a research contract between JAXA and Earthquake Research Institute (ERI), University of Tokyo. As ERI is a shared institute of the Japanese universities and research institutes, every scientist at all Japanese universities and institutes can participate in this consortium. The activity of PIXEL includes information exchange by mailing list, tutorial workshop for InSAR software, research workshop, and PALSAR data sharing. After the launch of ALOS, we have already witnessed several earthquakes and volcanic activities using PALSAR interferometry. We will briefly show and digest some of those observation results.

  5. Subsidence Monitoring in Seville (S Spain) Using Multi-Temporal InSAR

    Science.gov (United States)

    Ruiz-Armenteros, Antonio M.; Ruiz-Constan, Ana; Lamas-Fernandez, Francisco; Galindo-Zaldivar, Jesus; Sousa, Joaquim J.; Sanz de Galdeano, Carlos; Delgado, Manuel J.; Pedrera-Parias, Antonio; Martos-Rosillo, Sergio; Gil, Antonio J.; Caro-Cuenca, Miguel; Hanssen, Ramon F.

    2016-08-01

    Seville, with a metropolitan population of about 1.5 million, is the capital and largest city of Andalusia (S Spain). It is the 30th most populous municipality in the European Union and contains three UNESCO World Heritage Sites. The Seville harbour, located about 80 km from the Atlantic Ocean, is the only river port in Spain. The city is located on the plain of the Guadalquivir River. Using Multi-Temporal InSAR with ERS-1/2 and Envisat data a subsidence behavior is detected in the period 1992-2010. The geometry of the subsiding areas suggests that it should be conditioned by the fluvial dynamics of the Guadalquivir River and its tributaries. Facies distribution along the fluvial system (paleochannels, flood plains...), with different grain size and matrix proportion, may explain the relative subsidence between the different sectors.

  6. Dynamic, nondestructive imaging of a bioengineered vascular graft endothelium.

    Directory of Open Access Journals (Sweden)

    Bryce M Whited

    Full Text Available Bioengineering of vascular grafts holds great potential to address the shortcomings associated with autologous and conventional synthetic vascular grafts used for small diameter grafting procedures. Lumen endothelialization of bioengineered vascular grafts is essential to provide an antithrombogenic graft surface to ensure long-term patency after implantation. Conventional methods used to assess endothelialization in vitro typically involve periodic harvesting of the graft for histological sectioning and staining of the lumen. Endpoint testing methods such as these are effective but do not provide real-time information of endothelial cells in their intact microenvironment, rather only a single time point measurement of endothelium development. Therefore, nondestructive methods are needed to provide dynamic information of graft endothelialization and endothelium maturation in vitro. To address this need, we have developed a nondestructive fiber optic based (FOB imaging method that is capable of dynamic assessment of graft endothelialization without disturbing the graft housed in a bioreactor. In this study we demonstrate the capability of the FOB imaging method to quantify electrospun vascular graft endothelialization, EC detachment, and apoptosis in a nondestructive manner. The electrospun scaffold fiber diameter of the graft lumen was systematically varied and the FOB imaging system was used to noninvasively quantify the affect of topography on graft endothelialization over a 7-day period. Additionally, results demonstrated that the FOB imaging method had a greater imaging penetration depth than that of two-photon microscopy. This imaging method is a powerful tool to optimize vascular grafts and bioreactor conditions in vitro, and can be further adapted to monitor endothelium maturation and response to fluid flow bioreactor preconditioning.

  7. Enhancing the dynamic range of Ultrasound Imaging Velocimetry using interleaved imaging

    NARCIS (Netherlands)

    Poelma, C.; Fraser, K.H.

    2013-01-01

    In recent years, non-invasive velocity field measurement based on correlation of ultrasound images has been introduced as a promising technique for fundamental research into disease processes, as well as a diagnostic tool. A major drawback of the method is the relatively limited dynamic range when

  8. Analysis of Land Deformation on Slope Area using PS InSAR. Case Study: Malang Area

    International Nuclear Information System (INIS)

    Sudiana, Dodi; Rizkinia, Mia; Arief, Rahmat; Rokhmatuloh; Ardiansyah; Setiadi, Bambang; Bayuaji, Luhur; Sri Sumantyo, Josaphat Tetuko

    2014-01-01

    The geographical position of Indonesia located between two continents and oceans is strategic, but at large risk of experiencing various disasters. Climate change and vulnerable location (surrounded by plates and geological faults in the Earth's crust) creates an earthquake-prone region and causes land/mudslides. In this paper, PS InSAR method (Persistent Scatterer Interferometric Synthetic Aperture Radar) is implemented to Phased Array type L-band Synthetic Aperture Radar (PALSAR) data to study the potential damage caused by the earthquake or volcanic eruption in Malang vicinity. By comparing the amplitude images periodically, shifting soil can be determined using precise orbital information. The analysis showed a significant decrease of land deformation on slope area in Klojen district in Malang city, reached up to −7.128 mm/year

  9. Subsidence Evaluation of High-Speed Railway in Shenyang Based on Time-Series Insar

    Science.gov (United States)

    Zhang, Yun; Wei, Lianhuan; Li, Jiayu; Liu, Shanjun; Mao, Yachun; Wu, Lixin

    2018-04-01

    More and more high-speed railway are under construction in China. The slow settlement along high-speed railway tracks and newly-built stations would lead to inhomogeneous deformation of local area, and the accumulation may be a threat to the safe operation of high-speed rail system. In this paper, surface deformation of the newly-built high-speed railway station as well as the railway lines in Shenyang region will be retrieved by time series InSAR analysis using multi-orbit COSMO-SkyMed images. This paper focuses on the non-uniform subsidence caused by the changing of local environment along the railway. The accuracy of the settlement results can be verified by cross validation of the results obtained from two different orbits during the same period.

  10. Monitoring the Sumatra volcanic arc with InSAR

    Science.gov (United States)

    Chaussard, E.; Hong, S.; Amelung, F.

    2009-12-01

    The Sumatra volcanic arc is the result of the subduction of the Indo-Australian plate under the Sunda plate. The arc consists of 35 known volcanic centers, subaerials on the west coast of the Sumatra and Andaman Islands and submarines between these islands. Six active centers are known in the Sumatra volcanic arc. Surface deformation in volcanic areas usually indicates movement of magma or hydrothermal fluids at depth. Here we present a satellite-based Interferometric synthetic aperture radar (InSAR) survey of the Sumatra volcanic arc using ALOS data. Spanning the years 2007 to beginning of 2009, our survey reveals the background level of activity of the 35 volcanoes. We processed data from 40 tracks (24 in descending orbit and 16 in ascending orbit) to cover the whole Sumatra arc. In the first results five of these six known active centers show no sign of activity: Dempo, Kaba, Marapi, Talang and Peuet. The remaining active volcano, Mount Kerinci, has an ambiguous signal. We used pair-wise logic and InSAR time series of the available ALOS data to determine if the observed InSAR signal is caused by ground deformation or by atmospheric delays.

  11. A method for dynamic subtraction MR imaging of the liver

    Directory of Open Access Journals (Sweden)

    Setti Ernesto

    2006-06-01

    Full Text Available Abstract Background Subtraction of Dynamic Contrast-Enhanced 3D Magnetic Resonance (DCE-MR volumes can result in images that depict and accurately characterize a variety of liver lesions. However, the diagnostic utility of subtraction images depends on the extent of co-registration between non-enhanced and enhanced volumes. Movement of liver structures during acquisition must be corrected prior to subtraction. Currently available methods are computer intensive. We report a new method for the dynamic subtraction of MR liver images that does not require excessive computer time. Methods Nineteen consecutive patients (median age 45 years; range 37–67 were evaluated by VIBE T1-weighted sequences (TR 5.2 ms, TE 2.6 ms, flip angle 20°, slice thickness 1.5 mm acquired before and 45s after contrast injection. Acquisition parameters were optimized for best portal system enhancement. Pre and post-contrast liver volumes were realigned using our 3D registration method which combines: (a rigid 3D translation using maximization of normalized mutual information (NMI, and (b fast 2D non-rigid registration which employs a complex discrete wavelet transform algorithm to maximize pixel phase correlation and perform multiresolution analysis. Registration performance was assessed quantitatively by NMI. Results The new registration procedure was able to realign liver structures in all 19 patients. NMI increased by about 8% after rigid registration (native vs. rigid registration 0.073 ± 0.031 vs. 0.078 ± 0.031, n.s., paired t-test and by a further 23% (0.096 ± 0.035 vs. 0.078 ± 0.031, p t-test after non-rigid realignment. The overall average NMI increase was 31%. Conclusion This new method for realigning dynamic contrast-enhanced 3D MR volumes of liver leads to subtraction images that enhance diagnostic possibilities for liver lesions.

  12. Hepatocellular carcinoma on MR diffusion weighted imaging and dynamic contrast-enhanced imaging

    International Nuclear Information System (INIS)

    Dong Aisheng; Zuo Changjing; Tian Jianming; Lu Jianping; Wang Jian; Wang Li; Wang Fei

    2009-01-01

    Objective: To evaluate the findings of hepatocellular carcinoma (HCC) on DWI and dynamic Gd-DTPA-enhanced MR imaging. Methods: Eighty one patients with chronic hepatitis or liver cirrhosis underwent both DWI and dynamic Gd-DTPA-enhanced MRI studies of the liver for HCC detection. MR data of were retrospectively analyzed. Two observers determined in consensus the location and the number of focal lesions. The signal manifestation of the lesions on DWI and dynamic Gd-DTPA-enhanced MR imaging were analyzed. Results: DWI and Gd-DTPA-enhanced MR images detected 122 HCCs and 14 benign lesions. One hundred and sixteen HCCs (95.1%) showed hyperintensity on DWI and 6 HCCs in patients with severe cirrhosis showed isointensity. One hundred and five HCCs (86.1%) revealed hypointensity, 11 HCCs (9.0%) showed isointensity and 6 HCCs (4.9%) exhibited hyperintensity on T 1 weighted images. On Gd-DTPA-enhanced MR images, 101 HCCs(82.8%) were significantly enhanced on arterial phase and 99 HCCs showed hypointensity on portal and equilibrium phases. Twenty HCCs (16.4%), 18 of 20 less than 20 mm in diameter, showed isointensity on arterial phase and hyperintensity on DWI. Eight of 14 benign lesions showed hyperintensity and 6 isointensity on DWI. Five benign lesions with hypointensity on T 1 weighted images without contrast and hyperintensity on DWI showed no enhancement on Gd-DTPA-enhanced MR images; 6 benign lesions with isointensity on both T 1 weighted imaging without contrast and DWI exhibited avid enhancement on arterial phase and isointensty on portal and equilibrium phases; one of the two benign lesions, with isointensity before and after contrast images and hyperintentiy on DWI, was a regenerative nodule; another regenerative nodule with hyperintensity on both T 1 weighted images without contrast and DWI was greatly enhanced on arterial phase and showed isointensity on portal and equilibrium phases. Conclusions: Most of the HCCs were greatly enhanced on arterial phase on Gd

  13. Image processing pipeline for segmentation and material classification based on multispectral high dynamic range polarimetric images.

    Science.gov (United States)

    Martínez-Domingo, Miguel Ángel; Valero, Eva M; Hernández-Andrés, Javier; Tominaga, Shoji; Horiuchi, Takahiko; Hirai, Keita

    2017-11-27

    We propose a method for the capture of high dynamic range (HDR), multispectral (MS), polarimetric (Pol) images of indoor scenes using a liquid crystal tunable filter (LCTF). We have included the adaptive exposure estimation (AEE) method to fully automatize the capturing process. We also propose a pre-processing method which can be applied for the registration of HDR images after they are already built as the result of combining different low dynamic range (LDR) images. This method is applied to ensure a correct alignment of the different polarization HDR images for each spectral band. We have focused our efforts in two main applications: object segmentation and classification into metal and dielectric classes. We have simplified the segmentation using mean shift combined with cluster averaging and region merging techniques. We compare the performance of our segmentation with that of Ncut and Watershed methods. For the classification task, we propose to use information not only in the highlight regions but also in their surrounding area, extracted from the degree of linear polarization (DoLP) maps. We present experimental results which proof that the proposed image processing pipeline outperforms previous techniques developed specifically for MSHDRPol image cubes.

  14. Fast regional readout CMOS Image Sensor for dynamic MLC tracking

    Science.gov (United States)

    Zin, H.; Harris, E.; Osmond, J.; Evans, P.

    2014-03-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ~400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  15. Fast regional readout CMOS image sensor for dynamic MLC tracking

    International Nuclear Information System (INIS)

    Zin, H; Harris, E; Osmond, J; Evans, P

    2014-01-01

    Advanced radiotherapy techniques such as volumetric modulated arc therapy (VMAT) require verification of the complex beam delivery including tracking of multileaf collimators (MLC) and monitoring the dose rate. This work explores the feasibility of a prototype Complementary metal-oxide semiconductor Image Sensor (CIS) for tracking these complex treatments by utilising fast, region of interest (ROI) read out functionality. An automatic edge tracking algorithm was used to locate the MLC leaves edges moving at various speeds (from a moving triangle field shape) and imaged with various sensor frame rates. The CIS demonstrates successful edge detection of the dynamic MLC motion within accuracy of 1.0 mm. This demonstrates the feasibility of the sensor to verify treatment delivery involving dynamic MLC up to ∼400 frames per second (equivalent to the linac pulse rate), which is superior to any current techniques such as using electronic portal imaging devices (EPID). CIS provides the basis to an essential real-time verification tool, useful in accessing accurate delivery of complex high energy radiation to the tumour and ultimately to achieve better cure rates for cancer patients.

  16. Topological mass of magnetic Skyrmions probed by ultrafast dynamic imaging

    International Nuclear Information System (INIS)

    Buettner, Felix

    2013-01-01

    In this thesis, we investigate the GHz dynamics of skyrmionic spin structures by means of pump-probe dynamic imaging to determine the equation of motion that governs the behavior of these technologically relevant spin structures. To achieve this goal, we first designed and optimized a perpendicular magnetic anisotropy CoB/Pt multilayer material for low magnetic pinning, as required for ultrafast pump-probe imaging experiments. Second, we developed an integrated sample design for X-ray holography capable of tracking relative magnetic positional changes down to 3 nm spatial resolution. These advances enabled us to image the trajectory of a single magnetic Skyrmion. We find that the motion is comprised of two gyrotropic modes, one clockwise and one counterclockwise. The existence of two modes shows that Skyrmions are massive quasiparticles. From their derived frequencies we find an inertial mass for the Skyrmion which is a factor of five larger than expected based on existing models for inertia in magnetism. Our results demonstrate that the mass of Skyrmions is based on a novel mechanism emerging from their confined nature, which is a direct consequence of their topology.

  17. Dynamic MR imaging of hepatoma treated by transcatheter arterial embolization therapy

    International Nuclear Information System (INIS)

    Yamashita, Y.; Yoshimatsu, S.; Sumi, M.; Harada, M.; Takahashi, M.

    1993-01-01

    The effect of transcatheter arterial chemo-embolization theory (TACE) for hepatoma was evaluated with dynamic MR imaging with Gd-DTPA in 37 patients (44 tumors). TACE was performed using Lipiodol/cis-platinum and gelatin sponge (or microspheres) as an embolic material. All patients were examined with dynamic CT and MR imaging before and after treatment. On conventional spin echo images, changes of signal intensity after treatment varied regardless of presence of Lipiodol. Dynamic MR imaging revealed changes of tumor vascularity before and after treatment. On histologic correlation, areas of persistent tumor enhancement on dynamic MR imaging corresponded to areas of viable tumor cells while areas of nonenhancement corresponded to areas of necrosis. Dynamic MR imaging was superior in contrast resolution and was not influenced by the presence of Lipiodol compared with dynamic CT, and therefore residual viable tumors were better defined by dynamic MR imaging. (orig.)

  18. Assimilating InSAR Maps of Water Vapor to Improve Heavy Rainfall Forecasts: A Case Study With Two Successive Storms

    Science.gov (United States)

    Mateus, Pedro; Miranda, Pedro M. A.; Nico, Giovanni; Catalão, João.; Pinto, Paulo; Tomé, Ricardo

    2018-04-01

    Very high resolution precipitable water vapor maps obtained by the Sentinel-1 A synthetic aperture radar (SAR), using the SAR interferometry (InSAR) technique, are here shown to have a positive impact on the performance of severe weather forecasts. A case study of deep convection which affected the city of Adra, Spain, on 6-7 September 2015, is successfully forecasted by the Weather Research and Forecasting model initialized with InSAR data assimilated by the three-dimensional variational technique, with improved space and time distributions of precipitation, as observed by the local weather radar and rain gauge. This case study is exceptional because it consisted of two severe events 12 hr apart, with a timing that allows for the assimilation of both the ascending and descending satellite images, each for the initialization of each event. The same methodology applied to the network of Global Navigation Satellite System observations in Iberia, at the same times, failed to reproduce observed precipitation, although it also improved, in a more modest way, the forecast skill. The impact of precipitable water vapor data is shown to result from a direct increment of convective available potential energy, associated with important adjustments in the low-level wind field, favoring its release in deep convection. It is suggested that InSAR images, complemented by dense Global Navigation Satellite System data, may provide a new source of water vapor data for weather forecasting, since their sampling frequency could reach the subdaily scale by merging different SAR platforms, or when future geosynchronous radar missions become operational.

  19. InSAR Observations and Finite Element Modeling of Crustal Deformation Around a Surging Glacier, Iceland

    Science.gov (United States)

    Spaans, K.; Auriac, A.; Sigmundsson, F.; Hooper, A. J.; Bjornsson, H.; Pálsson, F.; Pinel, V.; Feigl, K. L.

    2014-12-01

    Icelandic ice caps, covering ~11% of the country, are known to be surging glaciers. Such process implies an important local crustal subsidence due to the large ice mass being transported to the ice edge during the surge in a few months only. In 1993-1995, a glacial surge occurred at four neighboring outlet glaciers in the southwestern part of Vatnajökull ice cap, the largest ice cap in Iceland. We estimated that ~16±1 km3 of ice have been moved during this event while the fronts of some of the outlet glaciers advanced by ~1 km.Surface deformation associated with this surge has been surveyed using Interferometric Synthetic Aperture Radar (InSAR) acquisitions from 1992-2002, providing high resolution ground observations of the study area. The data show about 75 mm subsidence at the ice edge of the outlet glaciers following the transport of the large volume of ice during the surge (Fig. 1). The long time span covered by the InSAR images enabled us to remove ~12 mm/yr of uplift occurring in this area due to glacial isostatic adjustment from the retreat of Vatnajökull ice cap since the end of the Little Ice Age in Iceland. We then used finite element modeling to investigate the elastic Earth response to the surge, as well as confirm that no significant viscoelastic deformation occurred as a consequence of the surge. A statistical approach based on Bayes' rule was used to compare the models to the observations and obtain an estimate of the Young's modulus (E) and Poisson's ratio (v) in Iceland. The best-fitting models are those using a one-kilometer thick top layer with v=0.17 and E between 12.9-15.3 GPa underlain by a layer with v=0.25 and E from 67.3 to 81.9 GPa. Results demonstrate that InSAR data and finite element models can be used successfully to reproduce crustal deformation induced by ice mass variations at Icelandic ice caps.Fig. 1: Interferograms spanning 1993 July 31 to 1995 June 19, showing the surge at Tungnaárjökull (Tu.), Skaftárjökull (Sk.) and S

  20. Dynamic and gated PET. Quantitative imaging of the heart revisited

    International Nuclear Information System (INIS)

    Nekolla, S.G.

    2005-01-01

    This short overview focuses on the basic implementation as well as applications of cardiac PET studies acquired in dynamic and ECG triggered modes. Both acquisition modes are well suited for quantitative analysis and the advantages of such an approach are discussed. An outlook on the measurement of respiratory triggered studies and the new challenges this data presents is provided. In the context of modern PET/CT tomographs with the combination of high sensitivity and morphologic resolution, the promise of list mode acquisition is investigated. The before mentioned acquisition modes are ideal candidates for this technology the utility of which in a clinical setting is briefly discussed. The retrospective generation of dynamic and gated image data (and any combinations) is greatly facilitated with this approach. Finally, a novel presentation mode for the wealth of quantitative information generated by these systems is presented. (orig.)

  1. Geocoronal imaging with Dynamics Explorer - A first look

    Science.gov (United States)

    Rairden, R. L.; Frank, L. A.; Craven, J. D.

    1983-01-01

    The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer. Previously announced in STAR as N83-20889

  2. Tunneling in a self-consistent dynamic image potential

    International Nuclear Information System (INIS)

    Rudberg, B.G.R.; Jonson, M.

    1991-01-01

    We have calculated the self-consistent effective potential for an electron tunneling through a square barrier while interacting with surface plasmons. This potential reduces to the classical image potential in the static limit. In the opposite limit, when the ''velocity'' of the tunneling electron is large, it reduces to the unperturbed square-barrier potential. For a wide variety of parameters the dynamic effects on the transmission coefficient T=|t 2 | can, for instance, be related to the Buettiker-Landauer traversal time for tunneling, given by τ BL =ℎ|d lnt/dV|

  3. Towards Slow-Moving Landslide Monitoring by Integrating Multi-Sensor InSAR Time Series Datasets: The Zhouqu Case Study, China

    Directory of Open Access Journals (Sweden)

    Qian Sun

    2016-11-01

    Full Text Available Although the past few decades have witnessed the great development of Synthetic Aperture Radar Interferometry (InSAR technology in the monitoring of landslides, such applications are limited by geometric distortions and ambiguity of 1D Line-Of-Sight (LOS measurements, both of which are the fundamental weakness of InSAR. Integration of multi-sensor InSAR datasets has recently shown its great potential in breaking through the two limits. In this study, 16 ascending images from the Advanced Land Observing Satellite (ALOS and 18 descending images from the Environmental Satellite (ENVISAT have been integrated to characterize and to detect the slow-moving landslides in Zhouqu, China between 2008 and 2010. Geometric distortions are first mapped by using the imaging geometric parameters of the used SAR data and public Digital Elevation Model (DEM data of Zhouqu, which allow the determination of the most appropriate data assembly for a particular slope. Subsequently, deformation rates along respective LOS directions of ALOS ascending and ENVISAT descending tracks are estimated by conducting InSAR time series analysis with a Temporarily Coherent Point (TCP-InSAR algorithm. As indicated by the geometric distortion results, 3D deformation rates of the Xieliupo slope at the east bank of the Pai-lung River are finally reconstructed by joint exploiting of the LOS deformation rates from cross-heading datasets based on the surface–parallel flow assumption. It is revealed that the synergistic results of ALOS and ENVISAT datasets provide a more comprehensive understanding and monitoring of the slow-moving landslides in Zhouqu.

  4. Application of DIRI dynamic infrared imaging in reconstructive surgery

    Science.gov (United States)

    Pawlowski, Marek; Wang, Chengpu; Jin, Feng; Salvitti, Matthew; Tenorio, Xavier

    2006-04-01

    We have developed the BioScanIR System based on QWIP (Quantum Well Infrared Photodetector). Data collected by this sensor are processed using the DIRI (Dynamic Infrared Imaging) algorithms. The combination of DIRI data processing methods with the unique characteristics of the QWIP sensor permit the creation of a new imaging modality capable of detecting minute changes in temperature at the surface of the tissue and organs associated with blood perfusion due to certain diseases such as cancer, vascular disease and diabetes. The BioScanIR System has been successfully applied in reconstructive surgery to localize donor flap feeding vessels (perforators) during the pre-surgical planning stage. The device is also used in post-surgical monitoring of skin flap perfusion. Since the BioScanIR is mobile; it can be moved to the bedside for such monitoring. In comparison to other modalities, the BioScanIR can localize perforators in a single, 20 seconds scan with definitive results available in minutes. The algorithms used include (FFT) Fast Fourier Transformation, motion artifact correction, spectral analysis and thermal image scaling. The BioScanIR is completely non-invasive and non-toxic, requires no exogenous contrast agents and is free of ionizing radiation. In addition to reconstructive surgery applications, the BioScanIR has shown promise as a useful functional imaging modality in neurosurgery, drug discovery in pre-clinical animal models, wound healing and peripheral vascular disease management.

  5. Carcinoma of the cervix. Value of dynamic magnetic resonance imaging in assessing early stromal invasion

    International Nuclear Information System (INIS)

    Kojima, Yumi; Aoki, Yoichi; Kase, Hiroaki; Kodama, Shoji; Tanaka, Kenichi

    1998-01-01

    The purpose of this study was to assess the accuracy of contrast-enhanced magnetic resonance imaging (dynamic MR imaging) in the evaluation of preinvasive and early invasive cancer of the cervix. Twenty-nine women with untreated squamous cell carcinoma of the cervix with either no stromal invasion or early stromal invasion underwent pretreatment MR imaging and dynamic MR imaging within 4 weeks of surgical evaluation. The images were evaluated for tumor detection and compared with results of histologic examination of the surgical specimens. The lesions in 17 cases with histologically proven stromal invasion of 4 mm or greater were detected with dynamic MR imaging, whereas lesions in only 8 of these cases were detected with T2 imaging. In 9 cases with stromal invasion between 4.0 mm and 5.0 mm, lesions were represented as early phase focal enhancement on dynamic MR images, but not detected on T2-weighted images. In the 12 cases with less than 4 mm stromal invasion, no lesions were visualized on either T2-weighted images or dynamic MR images, except in 1 case of glandular involvement without stromal invasion that appeared as enhancement on early-phase dynamic MR imaging. Dynamic MR imaging detected more lesions of early stromal invasion in pretreatment imaging for cervical cancer than nonenhanced MR imaging. (author)

  6. The Total Electron Content From InSAR and GNSS: A Midlatitude Study

    DEFF Research Database (Denmark)

    Musico, Elvira; Cesaroni, Claudio; Spogli, Luca

    2018-01-01

    The total electron content (TEC) measured from the interferometric synthetic aperture radar (InSAR) and froma dense network of global navigation satellite system (GNSS) receivers are used to assess the capability of InSAR to retrieve ionospheric information, when the tropospheric contribution...

  7. Constraints on timescales and mechanics of magmatic underplating from InSAR observations of large active magma sills in the Earth's crust.

    Science.gov (United States)

    Fialko, Y.

    2002-12-01

    Theoretical models of the granitoid magma generation due to magmatic underplating predict that anatectic melts are produced on quite short timescales of the order of the crystallization time of typical mafic underplates (e.g., 102-10^3 years for sill intrusions that are a few tens to a few hundred meters thick). If so, the intrusion of mafic underplates, the volume changes associated with in situ melting, and the subsequent evacuation of the resulting granitoid magmas can each generate geodetically observable deformation. Geodetic measurements in areas of contemporaneous large active magma bodies may therefore provide critical constraints on the timescales and dynamics of crustal anatexis. We use Interferometric Synthetic Aperture Radar (InSAR) observations in regions of the ongoing crustal magmatism to constrain typical rates of the large-scale melt generation and/or migration, and to test the proposed models of the granitic melt production. Our primary targets include large mid-crustal magma bodies imaged by seismic studies, in particular, the Socorro (New Mexico, USA), the Altiplano-Puna (south America), and the south Tibet (Asia) magma bodies. All these magma bodies are located at depth of 19-20 km, suggesting a strong rheological or buoyancy control on the transition from a vertical to a horizontal magma flow. Stacked interferometric data from the Socorro magma body indicate a quasi-steady uplift with a maximum rate of 3-4 mm/yr over the last 10 years covered by the InSAR observations. The uplift morphology can be well described by an elastic inflation of the Socorro sill. We show that deformation models that allow for the viscous-like rheology of the mid-to-lower crust cannot be easily reconciled with the geodetic data. However, thermodynamic modeling, in conjunction with inferences of the nearly constant uplift rates, suggest that the deformations associated with the intrusion emplacement must involve a significant inelastic component. Such inelastic

  8. Surface deformation induced by magmatic processes at Pacaya Volcano, Guatemala revealed by InSAR

    Science.gov (United States)

    Wnuk, K.; Wauthier, C.

    2017-09-01

    Pacaya Volcano, Guatemala is a continuously active, basaltic volcano with an unstable western flank. Despite continuous activity since 1961, a lack of high temporal resolution geodetic surveying has prevented detailed modeling of Pacaya's underlying magmatic plumbing system. A new, temporally dense dataset of Interferometric Synthetic Aperture Radar (InSAR) RADARSAT-2 images, spanning December 2012 to March 2014, show magmatic deformation before and during major eruptions in January and March 2014. Inversion of InSAR surface displacements using simple analytical forward models suggest that three magma bodies are responsible for the observed deformation: (1) a 4 km deep spherical reservoir located northwest of the summit, (2) a 0.4 km deep spherical source located directly west of the summit, and (3) a shallow dike below the summit. Periods of heightened volcanic activity are instigated by magma pulses at depth, resulting in rapid inflation of the edifice. We observe an intrusion cycle at Pacaya that consists of deflation of one or both magma reservoirs followed by dike intrusion. Intrusion volumes are proportional to reservoir volume loss and do not always result in an eruption. Periods of increased activity culminate with larger dike-fed eruptions. Large eruptions are followed by inter-eruptive periods marked by a decrease in crater explosions and a lack of detected deformation. Co-eruptive flank motion appears to have initiated a new stage of volcanic rifting at Pacaya defined by repeated NW-SE oriented dike intrusions. This creates a positive feedback relationship whereby magmatic forcing from eruptive dike intrusions induce flank motion.

  9. Permanent scatterer InSAR processing: Forsmark

    International Nuclear Information System (INIS)

    Dehls, John F.

    2006-04-01

    It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km 2 . Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of errors

  10. Permanent scatterer InSAR processing: Forsmark

    Energy Technology Data Exchange (ETDEWEB)

    Dehls, John F [Geological Survey of Norway, Trondheim (Norway)

    2006-04-15

    It has been speculated that slow, aseismic movement may be occurring along some of the fracture zones crosscutting the Forsmark area. The purpose of this study is to determine if it is possible to measure such movement using dInSAR. Differential SAR Interferometry (DInSAR) is a technique that compares the phases of multiple radar images of an area to measure surface change. The method has the potential to detect millimetric surface deformation along the sensor - target line-of-sight. Differences in phase between two images are easily viewed by combining, or interfering, the two phase-images. In the resulting image, the waves will either reinforce or cancel one another, depending upon the relative phases. The resulting image is called an interferogram and contains concentric bands of colour, or fringes, that are related to topography and/or surface deformation. New algorithms use many images acquired over a long time period to determine the movement history of individual objects, referred to as permanent scatterers. In the current project, standard PSInSAR processing was performed on 40 ERS-1 and ERS-2 scenes. The total area processed is approximately 1,500 km{sup 2}. Slightly less than 20,000 permanent scatterers were identified.The highest densities were obtained along the coast and on the islands, where natural outcrops are more abundant. Two main classes of objects act as permanent scatterers in this area. The first are natural reflectors, such as rocks. The second are man-made reflectors, such as parts of buildings. Numerous local movements were found in the study area, relating to building subsidence, or compaction of anthropogenic fill. The dataset was divided into three groups for analysis, based upon the location of regional lineaments provided by SKB. Both statistical and geostatistical techniques were used. The median velocity of the three blocks did not differ by more than 0.2 mm/yr. This is not considered significant, given the possible magnitude of

  11. Simultaneous reconstruction and segmentation for dynamic SPECT imaging

    International Nuclear Information System (INIS)

    Burger, Martin; Rossmanith, Carolin; Zhang, Xiaoqun

    2016-01-01

    This work deals with the reconstruction of dynamic images that incorporate characteristic dynamics in certain subregions, as arising for the kinetics of many tracers in emission tomography (SPECT, PET). We make use of a basis function approach for the unknown tracer concentration by assuming that the region of interest can be divided into subregions with spatially constant concentration curves. Applying a regularised variational framework reminiscent of the Chan-Vese model for image segmentation we simultaneously reconstruct both the labelling functions of the subregions as well as the subconcentrations within each region. Our particular focus is on applications in SPECT with the Poisson noise model, resulting in a Kullback–Leibler data fidelity in the variational approach. We present a detailed analysis of the proposed variational model and prove existence of minimisers as well as error estimates. The latter apply to a more general class of problems and generalise existing results in literature since we deal with a nonlinear forward operator and a nonquadratic data fidelity. A computational algorithm based on alternating minimisation and splitting techniques is developed for the solution of the problem and tested on appropriately designed synthetic data sets. For those we compare the results to those of standard EM reconstructions and investigate the effects of Poisson noise in the data. (paper)

  12. Dynamics of Corticosteroid Receptors: Lessons from Live Cell Imaging

    International Nuclear Information System (INIS)

    Nishi, Mayumi

    2011-01-01

    Adrenal corticosteroids (cortisol in humans or corticosterone in rodents) exert numerous effects on the central nervous system that regulates the stress response, mood, learning and memory, and various neuroendocrine functions. Corticosterone (CORT) actions in the brain are mediated via two receptor systems: the glucocorticoid receptor (GR) and the mineralocorticoid receptor (MR). It has been shown that GR and MR are highly colocalized in the hippocampus. These receptors are mainly distributed in the cytoplasm without hormones and translocated into the nucleus after treatment with hormones to act as transcriptional factors. Thus the subcellular dynamics of both receptors are one of the most important issues. Given the differential action of MR and GR in the central nervous system, it is of great consequence to clarify how these receptors are trafficked between cytoplasm and nucleus and their interactions are regulated by hormones and/or other molecules to exert their transcriptional activity. In this review, we focus on the nucleocytoplasmic and subnuclear trafficking of GR and MR in neural cells and non-neural cells analyzed by using molecular imaging techniques with green fluorescent protein (GFP) including fluorescence recovery after photobleaching (FRAP) and fluorescence resonance energy transfer (FRET), and discuss various factors affecting the dynamics of these receptors. Furthermore, we discuss the future directions of in vivo molecular imaging of corticosteroid receptors at the whole brain level

  13. Aircraft path planning for optimal imaging using dynamic cost functions

    Science.gov (United States)

    Christie, Gordon; Chaudhry, Haseeb; Kochersberger, Kevin

    2015-05-01

    Unmanned aircraft development has accelerated with recent technological improvements in sensing and communications, which has resulted in an "applications lag" for how these aircraft can best be utilized. The aircraft are becoming smaller, more maneuverable and have longer endurance to perform sensing and sampling missions, but operating them aggressively to exploit these capabilities has not been a primary focus in unmanned systems development. This paper addresses a means of aerial vehicle path planning to provide a realistic optimal path in acquiring imagery for structure from motion (SfM) reconstructions and performing radiation surveys. This method will allow SfM reconstructions to occur accurately and with minimal flight time so that the reconstructions can be executed efficiently. An assumption is made that we have 3D point cloud data available prior to the flight. A discrete set of scan lines are proposed for the given area that are scored based on visibility of the scene. Our approach finds a time-efficient path and calculates trajectories between scan lines and over obstacles encountered along those scan lines. Aircraft dynamics are incorporated into the path planning algorithm as dynamic cost functions to create optimal imaging paths in minimum time. Simulations of the path planning algorithm are shown for an urban environment. We also present our approach for image-based terrain mapping, which is able to efficiently perform a 3D reconstruction of a large area without the use of GPS data.

  14. Dynamic CT perfusion imaging of the myocardium: a technical note on improvement of image quality.

    Directory of Open Access Journals (Sweden)

    Daniela Muenzel

    Full Text Available OBJECTIVE: To improve image and diagnostic quality in dynamic CT myocardial perfusion imaging (MPI by using motion compensation and a spatio-temporal filter. METHODS: Dynamic CT MPI was performed using a 256-slice multidetector computed tomography scanner (MDCT. Data from two different patients-with and without myocardial perfusion defects-were evaluated to illustrate potential improvements for MPI (institutional review board approved. Three datasets for each patient were generated: (i original data (ii motion compensated data and (iii motion compensated data with spatio-temporal filtering performed. In addition to the visual assessment of the tomographic slices, noise and contrast-to-noise-ratio (CNR were measured for all data. Perfusion analysis was performed using time-density curves with regions-of-interest (ROI placed in normal and hypoperfused myocardium. Precision in definition of normal and hypoperfused areas was determined in corresponding coloured perfusion maps. RESULTS: The use of motion compensation followed by spatio-temporal filtering resulted in better alignment of the cardiac volumes over time leading to a more consistent perfusion quantification and improved detection of the extend of perfusion defects. Additionally image noise was reduced by 78.5%, with CNR improvements by a factor of 4.7. The average effective radiation dose estimate was 7.1±1.1 mSv. CONCLUSION: The use of motion compensation and spatio-temporal smoothing will result in improved quantification of dynamic CT MPI using a latest generation CT scanner.

  15. Two-photon imaging and analysis of neural network dynamics

    International Nuclear Information System (INIS)

    Luetcke, Henry; Helmchen, Fritjof

    2011-01-01

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  16. Two-photon imaging and analysis of neural network dynamics

    Science.gov (United States)

    Lütcke, Henry; Helmchen, Fritjof

    2011-08-01

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  17. Two-photon imaging and analysis of neural network dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Luetcke, Henry; Helmchen, Fritjof [Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)

    2011-08-15

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  18. First mesospheric wind images using the Michelson interferometer for airglow dynamics imaging.

    Science.gov (United States)

    Langille, J A; Ward, W E; Nakamura, T

    2016-12-10

    The Michelson interferometer for airglow dynamics imaging (MIADI) is a ground-based instrument that combines an imaging capability with the Doppler Michelson interferometry in order to remotely detect motions in the mesopause region using spectrally isolated airglow emissions: the O(S1) emission at 557.73 nm and the OH (6, 2) P1 (2) at 839.918 nm. A measurement and analysis approach has been developed that allows simultaneous images of the line-of-sight Doppler wind field and irradiance field to be obtained. A working field instrument was installed and tested at a field site outside Fredericton, NB (45.96 N, 66.65 W) during the summer of 2014. Successful measurements over a 6 h period were obtained on 31 July 2014. This paper describes the MIADI measurement and analysis approach and presents the work that has been done to extract images of the line-of-sight Doppler wind field and irradiances from these observations. The imaging capability is validated by identifying the presence of large-scale and small-scale geophysical perturbations in the images.

  19. Mutual information as a measure of image quality for 3D dynamic lung imaging with EIT.

    Science.gov (United States)

    Crabb, M G; Davidson, J L; Little, R; Wright, P; Morgan, A R; Miller, C A; Naish, J H; Parker, G J M; Kikinis, R; McCann, H; Lionheart, W R B

    2014-05-01

    We report on a pilot study of dynamic lung electrical impedance tomography (EIT) at the University of Manchester. Low-noise EIT data at 100 frames per second were obtained from healthy male subjects during controlled breathing, followed by magnetic resonance imaging (MRI) subsequently used for spatial validation of the EIT reconstruction. The torso surface in the MR image and electrode positions obtained using MRI fiducial markers informed the construction of a 3D finite element model extruded along the caudal-distal axis of the subject. Small changes in the boundary that occur during respiration were accounted for by incorporating the sensitivity with respect to boundary shape into a robust temporal difference reconstruction algorithm. EIT and MRI images were co-registered using the open source medical imaging software, 3D Slicer. A quantitative comparison of quality of different EIT reconstructions was achieved through calculation of the mutual information with a lung-segmented MR image. EIT reconstructions using a linear shape correction algorithm reduced boundary image artefacts, yielding better contrast of the lungs, and had 10% greater mutual information compared with a standard linear EIT reconstruction.

  20. Heuristic Scheduling Algorithm Oriented Dynamic Tasks for Imaging Satellites

    Directory of Open Access Journals (Sweden)

    Maocai Wang

    2014-01-01

    Full Text Available Imaging satellite scheduling is an NP-hard problem with many complex constraints. This paper researches the scheduling problem for dynamic tasks oriented to some emergency cases. After the dynamic properties of satellite scheduling were analyzed, the optimization model is proposed in this paper. Based on the model, two heuristic algorithms are proposed to solve the problem. The first heuristic algorithm arranges new tasks by inserting or deleting them, then inserting them repeatedly according to the priority from low to high, which is named IDI algorithm. The second one called ISDR adopts four steps: insert directly, insert by shifting, insert by deleting, and reinsert the tasks deleted. Moreover, two heuristic factors, congestion degree of a time window and the overlapping degree of a task, are employed to improve the algorithm’s performance. Finally, a case is given to test the algorithms. The results show that the IDI algorithm is better than ISDR from the running time point of view while ISDR algorithm with heuristic factors is more effective with regard to algorithm performance. Moreover, the results also show that our method has good performance for the larger size of the dynamic tasks in comparison with the other two methods.

  1. Sparse/Low Rank Constrained Reconstruction for Dynamic PET Imaging.

    Directory of Open Access Journals (Sweden)

    Xingjian Yu

    Full Text Available In dynamic Positron Emission Tomography (PET, an estimate of the radio activity concentration is obtained from a series of frames of sinogram data taken at ranging in duration from 10 seconds to minutes under some criteria. So far, all the well-known reconstruction algorithms require known data statistical properties. It limits the speed of data acquisition, besides, it is unable to afford the separated information about the structure and the variation of shape and rate of metabolism which play a major role in improving the visualization of contrast for some requirement of the diagnosing in application. This paper presents a novel low rank-based activity map reconstruction scheme from emission sinograms of dynamic PET, termed as SLCR representing Sparse/Low Rank Constrained Reconstruction for Dynamic PET Imaging. In this method, the stationary background is formulated as a low rank component while variations between successive frames are abstracted to the sparse. The resulting nuclear norm and l1 norm related minimization problem can also be efficiently solved by many recently developed numerical methods. In this paper, the linearized alternating direction method is applied. The effectiveness of the proposed scheme is illustrated on three data sets.

  2. Automatic Generation of Wide Dynamic Range Image without Pseudo-Edge Using Integration of Multi-Steps Exposure Images

    Science.gov (United States)

    Migiyama, Go; Sugimura, Atsuhiko; Osa, Atsushi; Miike, Hidetoshi

    Recently, digital cameras are offering technical advantages rapidly. However, the shot image is different from the sight image generated when that scenery is seen with the naked eye. There are blown-out highlights and crushed blacks in the image that photographed the scenery of wide dynamic range. The problems are hardly generated in the sight image. These are contributory cause of difference between the shot image and the sight image. Blown-out highlights and crushed blacks are caused by the difference of dynamic range between the image sensor installed in a digital camera such as CCD and CMOS and the human visual system. Dynamic range of the shot image is narrower than dynamic range of the sight image. In order to solve the problem, we propose an automatic method to decide an effective exposure range in superposition of edges. We integrate multi-step exposure images using the method. In addition, we try to erase pseudo-edges using the process to blend exposure values. Afterwards, we get a pseudo wide dynamic range image automatically.

  3. Groundwater depletion in Central Mexico: Use of GRACE and InSAR to support water resources management

    Science.gov (United States)

    Castellazzi, Pascal; Martel, Richard; Rivera, Alfonso; Huang, Jianliang; Pavlic, Goran; Calderhead, Angus I.; Chaussard, Estelle; Garfias, Jaime; Salas, Javier

    2016-08-01

    Groundwater deficits occur in several areas of Central Mexico, where water resource assessment is limited by the availability and reliability of field data. In this context, GRACE and InSAR are used to remotely assess groundwater storage loss in one of Mexico's most important watersheds in terms of size and economic activity: the Lerma-Santiago-Pacifico (LSP). In situ data and Land Surface Models are used to subtract soil moisture and surface water storage changes from the total water storage change measured by GRACE satellites. As a result, groundwater mass change time-series are obtained for a 12 years period. ALOS-PALSAR images acquired from 2007 to 2011 were processed using the SBAS-InSAR algorithm to reveal areas subject to ground motion related to groundwater over-exploitation. In the perspective of providing guidance for groundwater management, GRACE and InSAR observations are compared with official water budgets and field observations. InSAR-derived subsidence mapping generally agrees well with official water budgets, and shows that deficits occur mainly in cities and irrigated agricultural areas. GRACE does not entirely detect the significant groundwater losses largely reported by official water budgets, literature and InSAR observations. The difference is interpreted as returns of wastewater to the groundwater flow systems, which limits the watershed scale groundwater depletion but suggests major impacts on groundwater quality. This phenomenon is enhanced by ground fracturing as noticed in the field. Studying the fate of the extracted groundwater is essential when comparing GRACE data with higher resolution observations, and particularly in the perspective of further InSAR/GRACE combination in hydrogeology.

  4. Imaging vascular function for early stage clinical trials using dynamic contrast-enhanced magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Leach, M.O.; Orton, M. [Institute of Cancer Research and Royal Marsden NHS Foundation Trust, Cancer Research UK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Morgan, B. [Univ. of Leicester, College of Medicine, Biological Sciences and Psychology, Leicester (United Kingdom); Tofts, P.S. [Brighton and Sussex Medical School, Univ. of Sussex, Clinical Imaging Sciences Centre, Sussex (United Kingdom); Buckley, D.L. [University of Leeds, Division of Medical Physics, Leeds (United Kingdom); Huang, W. [Oregon Health and Science Univ., Advanced Imaging Research Centre, Portland, OR (United States); Horsfield, M.A. [Medical Physics Section, Leicester Royal Infirmary, Dept. of Cardiovascular Sciences, Leicester (United Kingdom); Chenevert, T.L. [Univ. of Michigan Health System, Ann Arbor, MI (United States); Collins, D.J. [Royal Marsden Hospital NHS Foundation Trust, Cancer Research UK and EPSRC Cancer Imaging Centre, Sutton, Surrey (United Kingdom); Jackson, A. [Univ. of Manchester, Wolfson Molecular Imaging Centre, Withington, Manchester, M20 3LJ (United Kingdom); Lomas, D. [Univ. of Cambridge, Dept. of Radiology, Cambridge (United Kingdom); Whitcher, B. [Unit 2 Greenways Business Park, Mango Solutions, Chippenham (United Kingdom); Clarke, L. [Cancer Imaging Program, Imaging Technology Development Branch, Rockville, MD (United States); Plummer, R. [Univ. of Newcastle Upon Tyne, The Medical School, Medical Oncology, Northern Inst. for Cancer Research, Newcastle Upon Tyne (United Kingdom); Judson, I. [Royal Marsden Hospital, Sutton, Surrey (United Kingdom); Jones, R. [Beatson West of Scotland Cancer Centre, Glasgow (United Kingdom); Alonzi, R. [Mount Vernon Cancer Centre, Northwood (United Kingdom); Brunner, T. [Gray Inst. for Radiation, Oncology and Biology, Oxford (United Kingdom); Koh, D.M. [Royal Marsden NHS Foundation Trust, Diagnostic Radiology, Sutton, Surrey (United Kingdom)] [and others

    2012-07-15

    Many therapeutic approaches to cancer affect the tumour vasculature, either indirectly or as a direct target. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has become an important means of investigating this action, both pre-clinically and in early stage clinical trials. For such trials, it is essential that the measurement process (i.e. image acquisition and analysis) can be performed effectively and with consistency among contributing centres. As the technique continues to develop in order to provide potential improvements in sensitivity and physiological relevance, there is considerable scope for between-centre variation in techniques. A workshop was convened by the Imaging Committee of the Experimental Cancer Medicine Centres (ECMC) to review the current status of DCE-MRI and to provide recommendations on how the technique can best be used for early stage trials. This review and the consequent recommendations are summarised here. (orig.)

  5. Dynamic low dose I-123-iodophenylpentadecanoic acid metabolic cardiac imaging

    International Nuclear Information System (INIS)

    Murray, G.L.; Magill, H.L.; Schad, N.C.

    1993-01-01

    Recognition of stunned and hibernating myocardium is essential in this era of cardiac revascularization. Positron emission tomography (PET) accurately identifies viability but is costly and unavailable to most patients. Dynamic low dose I-123-iodophenylpentadecanoic acid (IPPA) metabolic cardiac imaging is a potentially cost-effective alternative to PET. Using transmural myocardial biopsies obtained during coronary bypass surgery as the viability gold standard, resting IPPA imaging agreed with 39/43 (91%) biopsies, with a sensitivity for viability of 33/36(92%) and a specificity of 6/7 (86%) in patients with severe ischemic cardiomyopathy. Eighty percent of IPPA viable, infarcted segments improved wall motion postoperatively. Furthermore, when compared to reinjection thallium (SPECT-Tl) scans after myocardial infarction, there was IPPA-Tl concordance in 27/35 (77%)(Kappa=0.536, p=0.0003). Similar to PET, IPPA demonstrated more viability than SPECT-Tl, 26/35 (74%) vs. 18/35 (51%)(p=0.047). Finally, when compared to transvenous endomyocardial biopsy for detecting rejection following cardiac transplantation, IPPA sensitivity for ≥Grade II rejection was 100%, and IPPA screening assessment for the necessity of biopsy could result in a 31% cost-savings. Therefore, IPPA metabolic cardiac imaging is a safe, inexpensive technique with a promising future. (author)

  6. Measurements of granular flow dynamics with high speed digital images

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jingeol [Univ. of Florida, Gainesville, FL (United States)

    1994-01-01

    The flow of granular materials is common to many industrial processes. This dissertation suggests and validates image processing algorithms applied to high speed digital images to measure the dynamics (velocity, temperature and volume fraction) of dry granular solids flowing down an inclined chute under the action of gravity. Glass and acrylic particles have been used as granular solids in the experiment. One technique utilizes block matching for spatially averaged velocity measurements of the glass particles. This technique is compared with the velocity measurement using an optic probe which is a conventional granular flow velocity measurement device. The other technique for measuring the velocities of individual acrylic particles is developed with correspondence using a Hopfield network. This technique first locates the positions of particles with pattern recognition techniques, followed by a clustering technique, which produces point patterns. Also, several techniques are compared for particle recognition: synthetic discriminant function (SDF), minimum average correlation energy (MACE) filter, modified minimum average correlation energy (MMACE) filter and variance normalized correlation. The author proposes an MMACE filter which improves generalization of the MACE filter by adjusting the amount of averaged spectrum of training images in the spectrum whitening stages of the MACE filter. Variance normalized correlation is applied to measure the velocity and temperature of flowing glass particles down the inclined chute. The measurements are taken for the steady and wavy flow and qualitatively compared with a theoretical model of granular flow.

  7. Dynamics of Kilauea's Magmatic System Imaged Using a Joint Analysis of Geodetic and Seismic Data

    Science.gov (United States)

    Wauthier, C.; Roman, D. C.; Poland, M. P.; Fukushima, Y.; Hooper, A. J.

    2012-12-01

    Nowadays, Interferometric Synthetic Aperture Radar (InSAR) is commonly used to study a wide range of active volcanic areas. InSAR provides high-spatial-resolution measurements of surface deformation with centimeter-scale accuracy. At Kilauea Volcano, Hawai'i, InSAR shows complex processes that are not well constrained by GPS data (which have relatively poor spatial resolution). However, GPS data have higher temporal resolution than InSAR data. Both datasets are thus complementary. To overcome some of the limitations of conventional InSAR, which are mainly induced by temporal decorrelation, topographic, orbital and atmospheric delays, a Multi-Temporal InSAR (MT-InSAR) approach can be used. MT-InSAR techniques involve the processing of multiple SAR acquisitions over the same area. Two classes of MT-InSAR algorithms are defined: the persistent scatterers (PS) and small baseline (SBAS) methods. Each method is designed for a specific type of scattering mechanism. A PS pixel is a pixel in which a single scatterer dominates, while the contributions from other scatterers are negligible. A SBAS pixel is a pixel that includes distributed scatterers, which have a phase with little decorrelation over short time periods. Here, we apply the "StaMPS" ("Stanford Method for Permanent Scatterers") technique, which incorporates both a PS and SBAS approach, on ENVISAT and ALOS datasets acquired from 2003 to 2010 at Kilauea. In particular, we focus our InSAR analysis on the time period before the June 2007 "Father's Day" dike intrusion and eruption, and also incorporate seismic and GPS data in our models. Our goal is to identify any precursors to the Father's Day event within Kilauea's summit magma system, east rift zone, and/or southwest rift zone.

  8. Comparing the difference of measured GFR of ectopic pelvic kidney between anterior and posterior imaging processing in renal dynamic imaging

    International Nuclear Information System (INIS)

    Li Baojun; Zhao Deshan

    2014-01-01

    Objective: To compare and analyze the difference of measured glomerular filtration rate (GFR) of ectopic pelvic kidney between anterior and posterior imaging processing in renal dynamic imaging. Methods: There were 10 patients collected retrospectively, with ectopic kidneys in pelvic cavity confirmed by ultrasound, CT, renal dynamic imaging and other imaging modalities. All images of ectopic kidneys in renal dynamic imaging were processed by anterior and posterior methods respectively. The ectopic kidney was only processed in anterior imaging, ectopic kidney and contralateral normal kidney were processed in posterior imaging. Total GFR equalled the sum of GFR of normal kidney in posterior imaging and GFR of ectopic kidney in anterior imaging, was compared with total GFR of two kidneys in posterior imaging and GFR in two-sample method. All correlation analysis were completed between GFRs from three methods and all patients were followed up. Statistically paired t-test and bivariate correlation analysis test were used. Results: The mean GFR of ectopic kidney in anterior imaging equal to (27.48±12.24) ml/(min · 1.73 m 2 ). It was more than GFR [(10.71 ±4.74) ml/ (min · 1.73 m 2 )] in posterior imaging above 46% (t=5.481, P<0.01). There was no significant difference (t=-2.238, P>0.05), but better correlation (r=0.704, P<0.05) between total GFR in anterior imaging and GFR in two-sample method. There was significant difference (t=4.629, P<0.01)and worse correlation (r=0.576, P>0.05) between total GFR in posterior imaging and GFR in two-sample method. Conclusion: Comparing with GFR in posterior imaging, GFR in anterior imaging can more truly reflect function condition of ectopic pelvic kidney in renal dynamic imaging. (authors)

  9. Development of a dynamic flow imaging phantom for dynamic contrast-enhanced CT

    International Nuclear Information System (INIS)

    Driscoll, B.; Keller, H.; Coolens, C.

    2011-01-01

    Purpose: Dynamic contrast enhanced CT (DCE-CT) studies with modeling of blood flow and tissue perfusion are becoming more prevalent in the clinic, with advances in wide volume CT scanners allowing the imaging of an entire organ with sub-second image frequency and sub-millimeter accuracy. Wide-spread implementation of perfusion DCE-CT, however, is pending fundamental validation of the quantitative parameters that result from dynamic contrast imaging and perfusion modeling. Therefore, the goal of this work was to design and construct a novel dynamic flow imaging phantom capable of producing typical clinical time-attenuation curves (TACs) with the purpose of developing a framework for the quantification and validation of DCE-CT measurements and kinetic modeling under realistic flow conditions. Methods: The phantom is based on a simple two-compartment model and was printed using a 3D printer. Initial analysis of the phantom involved simple flow measurements and progressed to DCE-CT experiments in order to test the phantoms range and reproducibility. The phantom was then utilized to generate realistic input TACs. A phantom prediction model was developed to compute the input and output TACs based on a given set of five experimental (control) parameters: pump flow rate, injection pump flow rate, injection contrast concentration, and both control valve positions. The prediction model is then inversely applied to determine the control parameters necessary to generate a set of desired input and output TACs. A protocol was developed and performed using the phantom to investigate image noise, partial volume effects and CT number accuracy under realistic flow conditionsResults: This phantom and its surrounding flow system are capable of creating a wide range of physiologically relevant TACs, which are reproducible with minimal error between experiments (σ/μ 2 ) for the input function between 0.95 and 0.98, while the maximum enhancement differed by no more than 3.3%. The

  10. Characterization of Enhancing MS Lesions by Dynamic Texture Parameter Analysis of Dynamic Susceptibility Perfusion Imaging

    Directory of Open Access Journals (Sweden)

    Rajeev K. Verma

    2016-01-01

    Full Text Available Purpose. The purpose of this study was to investigate statistical differences with MR perfusion imaging features that reflect the dynamics of Gadolinium-uptake in MS lesions using dynamic texture parameter analysis (DTPA. Methods. We investigated 51 MS lesions (25 enhancing, 26 nonenhancing lesions of 12 patients. Enhancing lesions (n=25 were prestratified into enhancing lesions with increased permeability (EL+; n=11 and enhancing lesions with subtle permeability (EL−; n=14. Histogram-based feature maps were computed from the raw DSC-image time series and the corresponding texture parameters were analyzed during the inflow, outflow, and reperfusion time intervals. Results. Significant differences (p<0.05 were found between EL+ and EL− and between EL+ and nonenhancing inactive lesions (NEL. Main effects between EL+ versus EL− and EL+ versus NEL were observed during reperfusion (mainly in mean and standard deviation (SD: EL+ versus EL− and EL+ versus NEL, while EL− and NEL differed only in their SD during outflow. Conclusion. DTPA allows grading enhancing MS lesions according to their perfusion characteristics. Texture parameters of EL− were similar to NEL, while EL+ differed significantly from EL− and NEL. Dynamic texture analysis may thus be further investigated as noninvasive endogenous marker of lesion formation and restoration.

  11. High Dynamic Velocity Range Particle Image Velocimetry Using Multiple Pulse Separation Imaging

    Directory of Open Access Journals (Sweden)

    Tadhg S. O’Donovan

    2010-12-01

    Full Text Available The dynamic velocity range of particle image velocimetry (PIV is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS technique (i records series of double-frame exposures with different pulse separations, (ii processes the fields using conventional multi-grid algorithms, and (iii yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  12. High dynamic velocity range particle image velocimetry using multiple pulse separation imaging.

    Science.gov (United States)

    Persoons, Tim; O'Donovan, Tadhg S

    2011-01-01

    The dynamic velocity range of particle image velocimetry (PIV) is determined by the maximum and minimum resolvable particle displacement. Various techniques have extended the dynamic range, however flows with a wide velocity range (e.g., impinging jets) still challenge PIV algorithms. A new technique is presented to increase the dynamic velocity range by over an order of magnitude. The multiple pulse separation (MPS) technique (i) records series of double-frame exposures with different pulse separations, (ii) processes the fields using conventional multi-grid algorithms, and (iii) yields a composite velocity field with a locally optimized pulse separation. A robust criterion determines the local optimum pulse separation, accounting for correlation strength and measurement uncertainty. Validation experiments are performed in an impinging jet flow, using laser-Doppler velocimetry as reference measurement. The precision of mean flow and turbulence quantities is significantly improved compared to conventional PIV, due to the increase in dynamic range. In a wide range of applications, MPS PIV is a robust approach to increase the dynamic velocity range without restricting the vector evaluation methods.

  13. Improvement of temporal and dynamic subtraction images on abdominal CT using 3D global image matching and nonlinear image warping techniques

    International Nuclear Information System (INIS)

    Okumura, E; Sanada, S; Suzuki, M; Takemura, A; Matsui, O

    2007-01-01

    Accurate registration of the corresponding non-enhanced and arterial-phase CT images is necessary to create temporal and dynamic subtraction images for the enhancement of subtle abnormalities. However, respiratory movement causes misregistration at the periphery of the liver. To reduce these misregistration errors, we developed a temporal and dynamic subtraction technique to enhance small HCC by 3D global matching and nonlinear image warping techniques. The study population consisted of 21 patients with HCC. Using the 3D global matching and nonlinear image warping technique, we registered current and previous arterial-phase CT images or current non-enhanced and arterial-phase CT images obtained in the same position. The temporal subtraction image was obtained by subtracting the previous arterial-phase CT image from the warped current arterial-phase CT image. The dynamic subtraction image was obtained by the subtraction of the current non-enhanced CT image from the warped current arterial-phase CT image. The percentage of fair or superior temporal subtraction images increased from 52.4% to 95.2% using the new technique, while on the dynamic subtraction images, the percentage increased from 66.6% to 95.2%. The new subtraction technique may facilitate the diagnosis of subtle HCC based on the superior ability of these subtraction images to show nodular and/or ring enhancement

  14. Nephron blood flow dynamics measured by laser speckle contrast imaging

    DEFF Research Database (Denmark)

    von Holstein-Rathlou, Niels-Henrik; Sosnovtseva, Olga V; Pavlov, Alexey N

    2011-01-01

    Tubuloglomerular feedback (TGF) has an important role in autoregulation of renal blood flow and glomerular filtration rate (GFR). Because of the characteristics of signal transmission in the feedback loop, the TGF undergoes self-sustained oscillations in single-nephron blood flow, GFR, and tubular...... simultaneously. The interacting nephron fields are likely to be more extensive. We have turned to laser speckle contrast imaging to measure the blood flow dynamics of 50-100 nephrons simultaneously on the renal surface of anesthetized rats. We report the application of this method and describe analytic...... pressure and flow. Nephrons interact by exchanging electrical signals conducted electrotonically through cells of the vascular wall, leading to synchronization of the TGF-mediated oscillations. Experimental studies of these interactions have been limited to observations on two or at most three nephrons...

  15. Focal dynamics of multiple filaments: Microscopic imaging and reconstruction

    International Nuclear Information System (INIS)

    Kiran, P. Prem; Bagchi, Suman; Kumar, G. Ravindra; Krishnan, Siva Rama; Arnold, C. L.; Couairon, A.

    2010-01-01

    We observe the complete dynamics of the propagation of very intense, femtosecond laser pulses in air under tight focusing conditions via direct imaging of the entire interaction zone. The whole life history of the focused pulses is then reconstructed by means of numerical simulations. We show that beam breakup leads to a dual-rate increase in filament numbers with laser power. Linearly and circularly polarized pulses give rise to beam breakup and fusion governed by external focusing conditions. For tight focusing conditions, intensity saturation due to plasma generation and nonlinear losses does not limit the intensity growth, thereby giving access to a new propagation regime featured by an efficient laser energy deposition in fully ionized air and intense 10 15 W/cm 2 pulses at the focus.

  16. Assessment of femoral head perfusion by dynamic MR imaging

    International Nuclear Information System (INIS)

    Ochi, Ryuya; Nakano, Tetsuo; Miyazono, Kazuki; Tsurugami, Hiroshi; Fukuda, Tomohiro; Inaba, Daisuke; Takada, Koji

    2004-01-01

    We studied femoral head perfusion in 21 femoral neck fractures using dynamic MR imaging (MRI) between November 2001 and July 2002. MRI patterns divided into four groups when the results between the fractured side and unaffected side were compared. Femoral head perfusion at the fractured side was normal in Type A, about half in Type B, and absent in Type C. When perfusion at both the fractured side and unaffected side was absent, Exceptional Type was suspected. The Garden I group consisted of one Type B. The Garden II group consisted of one Type A, six Type B, one Type C, and two Exceptional Type. The Garden III group consisted of two Type B and one Type C, and the Garden IV group consisted of six Type C and one Exceptional Type. Post operations of by internal fixation confirmed the incidence of aseptic necrosis using MRI. (author)

  17. Increasing Linear Dynamic Range of a CMOS Image Sensor

    Science.gov (United States)

    Pain, Bedabrata

    2007-01-01

    A generic design and a corresponding operating sequence have been developed for increasing the linear-response dynamic range of a complementary metal oxide/semiconductor (CMOS) image sensor. The design provides for linear calibrated dual-gain pixels that operate at high gain at a low signal level and at low gain at a signal level above a preset threshold. Unlike most prior designs for increasing dynamic range of an image sensor, this design does not entail any increase in noise (including fixed-pattern noise), decrease in responsivity or linearity, or degradation of photometric calibration. The figure is a simplified schematic diagram showing the circuit of one pixel and pertinent parts of its column readout circuitry. The conventional part of the pixel circuit includes a photodiode having a small capacitance, CD. The unconventional part includes an additional larger capacitance, CL, that can be connected to the photodiode via a transfer gate controlled in part by a latch. In the high-gain mode, the signal labeled TSR in the figure is held low through the latch, which also helps to adapt the gain on a pixel-by-pixel basis. Light must be coupled to the pixel through a microlens or by back illumination in order to obtain a high effective fill factor; this is necessary to ensure high quantum efficiency, a loss of which would minimize the efficacy of the dynamic- range-enhancement scheme. Once the level of illumination of the pixel exceeds the threshold, TSR is turned on, causing the transfer gate to conduct, thereby adding CL to the pixel capacitance. The added capacitance reduces the conversion gain, and increases the pixel electron-handling capacity, thereby providing an extension of the dynamic range. By use of an array of comparators also at the bottom of the column, photocharge voltages on sampling capacitors in each column are compared with a reference voltage to determine whether it is necessary to switch from the high-gain to the low-gain mode. Depending upon

  18. Exploiting Fission Chain Reaction Dynamics to Image Fissile Materials

    Science.gov (United States)

    Chapman, Peter Henry

    Radiation imaging is one potential method to verify nuclear weapons dismantlement. The neutron coded aperture imager (NCAI), jointly developed by Oak Ridge National Laboratory (ORNL) and Sandia National Laboratories (SNL), is capable of imaging sources of fast (e.g., fission spectrum) neutrons using an array of organic scintillators. This work presents a method developed to discriminate between non-multiplying (i.e., non-fissile) neutron sources and multiplying (i.e., fissile) neutron sources using the NCAI. This method exploits the dynamics of fission chain-reactions; it applies time-correlated pulse-height (TCPH) analysis to identify neutrons in fission chain reactions. TCPH analyzes the neutron energy deposited in the organic scintillator vs. the apparent neutron time-of-flight. Energy deposition is estimated from light output, and time-of-flight is estimated from the time between the neutron interaction and the immediately preceding gamma interaction. Neutrons that deposit more energy than can be accounted for by their apparent time-of-flight are identified as fission chain-reaction neutrons, and the image is reconstructed using only these neutron detection events. This analysis was applied to measurements of weapons-grade plutonium (WGPu) metal and 252Cf performed at the Nevada National Security Site (NNSS) Device Assembly Facility (DAF) in July 2015. The results demonstrate it is possible to eliminate the non-fissile 252Cf source from the image while preserving the fissileWGPu source. TCPH analysis was also applied to additional scenes in which theWGPu and 252Cf sources were measured individually. The results of these separate measurements further demonstrate the ability to remove the non-fissile 252Cf source and retain the fissileWGPu source. Simulations performed using MCNPX-PoliMi indicate that in a one hour measurement, solid spheres ofWGPu are retained at a 1sigma level for neutron multiplications M -˜ 3.0 and above, while hollowWGPu spheres are

  19. Quantitative and Dynamic Imaging of ATM Kinase Activity.

    Science.gov (United States)

    Nyati, Shyam; Young, Grant; Ross, Brian Dale; Rehemtulla, Alnawaz

    2017-01-01

    Ataxia telangiectasia mutated (ATM) is a serine/threonine kinase critical to the cellular DNA-damage response, including DNA double-strand breaks (DSBs). ATM activation results in the initiation of a complex cascade of events facilitating DNA damage repair, cell cycle checkpoint control, and survival. Traditionally, protein kinases have been analyzed in vitro using biochemical methods (kinase assays using purified proteins or immunological assays) requiring a large number of cells and cell lysis. Genetically encoded biosensors based on optical molecular imaging such as fluorescence or bioluminescence have been developed to enable interrogation of kinase activities in live cells with a high signal to background. We have genetically engineered a hybrid protein whose bioluminescent activity is dependent on the ATM-mediated phosphorylation of a substrate. The engineered protein consists of the split luciferase-based protein complementation pair with a CHK2 (a substrate for ATM kinase activity) target sequence and a phospho-serine/threonine-binding domain, FHA2, derived from yeast Rad53. Phosphorylation of the serine residue within the target sequence by ATM would lead to its interaction with the phospho-serine-binding domain, thereby preventing complementation of the split luciferase pair and loss of reporter activity. Bioluminescence imaging of reporter expressing cells in cultured plates or as mouse xenografts provides a quantitative surrogate for ATM kinase activity and therefore the cellular DNA damage response in a noninvasive, dynamic fashion.

  20. Evaluation of renal transplants with Gd-DOTA dynamic MR imaging with factor analysis

    International Nuclear Information System (INIS)

    Chabrials, J.; Frouin, F.; Helenon, O.; Benall, H.; Kreis, H.; Moreau, J.F.; Di Paola, R.

    1990-01-01

    This paper reports on renal and urinary excretion factors by means of Gd-DOTA dynamic MR imaging and using factor analysis of dynamic structure (FADS) to follow-up renal transplants. We examined 60 patients with renal transplants by use of dynamic MR imaging after administration of a Gd-DOTA bolus (0.2 ml/kg) on a 0.5-T system; 10--12 fast gradient-echo sequences (TR/TE = 40/14, flip angle = 45 degree, acquisition time = 13 seconds) with single images and a 32-second intersequence delay were used. Of these, 13 dynamic MR imaging sequences were processed with an extension to dynamic MR images of FADS, previously developed to analyze nuclear medicine dynamic studies. The results were compared with the results of biologic dosages, renal biopsy and Seldinger digital arteriography

  1. The 2008 Wells, Nevada earthquake sequence: Source constraints using calibrated multiple event relocation and InSAR

    Science.gov (United States)

    Nealy, Jennifer; Benz, Harley M.; Hayes, Gavin; Berman, Eric; Barnhart, William

    2017-01-01

    The 2008 Wells, NV earthquake represents the largest domestic event in the conterminous U.S. outside of California since the October 1983 Borah Peak earthquake in southern Idaho. We present an improved catalog, magnitude complete to 1.6, of the foreshock-aftershock sequence, supplementing the current U.S. Geological Survey (USGS) Preliminary Determination of Epicenters (PDE) catalog with 1,928 well-located events. In order to create this catalog, both subspace and kurtosis detectors are used to obtain an initial set of earthquakes and associated locations. The latter are then calibrated through the implementation of the hypocentroidal decomposition method and relocated using the BayesLoc relocation technique. We additionally perform a finite fault slip analysis of the mainshock using InSAR observations. By combining the relocated sequence with the finite fault analysis, we show that the aftershocks occur primarily updip and along the southwestern edge of the zone of maximum slip. The aftershock locations illuminate areas of post-mainshock strain increase; aftershock depths, ranging from 5 to 16 km, are consistent with InSAR imaging, which shows that the Wells earthquake was a buried source with no observable near-surface offset.

  2. Evaluation of the SBAS InSAR Service of the European Space Agency’s Geohazard Exploitation Platform (GEP

    Directory of Open Access Journals (Sweden)

    Jorge Pedro Galve

    2017-12-01

    Full Text Available The analysis of remote sensing data to assess geohazards is being improved by web-based platforms and collaborative projects, such as the Geohazard Exploitation Platform (GEP of the European Space Agency (ESA. This paper presents the evaluation of a surface velocity map that is generated by this platform. The map was produced through an unsupervised Multi-temporal InSAR (MTI analysis applying the Parallel-SBAS (P-SBAS algorithm to 25 ENVISAT satellite images from the South of Spain that were acquired between 2003 and 2008. This analysis was carried out using a service implemented in the GEP called “SBAS InSAR”. Thanks to the map that was generated by the SBAS InSAR service, we identified processes not documented so far; provided new monitoring data in places affected by known ground instabilities; defined the area affected by these instabilities; and, studied a case where GEP could have been able to help in the forecast of a slope movement reactivation. This amply demonstrates the reliability and usefulness of the GEP, and shows how web-based platforms may enhance the capacity to identify, monitor, and assess hazards that are associated to geological processes.

  3. Land subsidence, Ground Fissures and Buried Faults: InSAR Monitoring of Ciudad Guzmán (Jalisco, Mexico

    Directory of Open Access Journals (Sweden)

    Carlo Alberto Brunori

    2015-07-01

    Full Text Available We study land subsidence processes and the associated ground fissuring, affecting an active graben filled by thick unconsolidated deposits by means of InSAR techniques and fieldwork. On 21 September 2012, Ciudad Guzmán (Jalisco, Mexico was struck by ground fissures of about 1.5 km of length, causing the deformation of the roads and the propagation of fissures in adjacent buildings. The field survey showed that fissures alignment is coincident with the escarpments produced on 19 September 1985, when a strong earthquake with magnitude 8.1 struck central Mexico. In order to detect and map the spatio-temporal features of the processes that led to the 2012 ground fissures, we applied InSAR multi-temporal techniques to process ENVISAT-ASAR and RADARSAT-2 satellite SAR images acquired between 2003 and 2012. We detect up to 20 mm/year of subsidence of the northwestern part of Ciudad Guzmán. These incremental movements are consistent with the ground fissures observed in 2012. Based on interferometric results, field data and 2D numerical model, we suggest that ground deformations and fissuring are due to the presence of areal subsidence correlated with variable sediment thickness and differential compaction, partly driven by the exploitation of the aquifers and controlled by the distribution and position of buried faults.

  4. Sea ice local surface topography from single-pass satellite InSAR measurements: a feasibility study

    Directory of Open Access Journals (Sweden)

    W. Dierking

    2017-08-01

    Full Text Available Quantitative parameters characterizing the sea ice surface topography are needed in geophysical investigations such as studies on atmosphere–ice interactions or sea ice mechanics. Recently, the use of space-borne single-pass interferometric synthetic aperture radar (InSAR for retrieving the ice surface topography has attracted notice among geophysicists. In this paper the potential of InSAR measurements is examined for several satellite configurations and radar frequencies, considering statistics of heights and widths of ice ridges as well as possible magnitudes of ice drift. It is shown that, theoretically, surface height variations can be retrieved with relative errors  ≤  0.5 m. In practice, however, the sea ice drift and open water leads may contribute significantly to the measured interferometric phase. Another essential factor is the dependence of the achievable interferometric baseline on the satellite orbit configurations. Possibilities to assess the influence of different factors on the measurement accuracy are demonstrated: signal-to-noise ratio, presence of a snow layer, and the penetration depth into the ice. Practical examples of sea surface height retrievals from bistatic SAR images collected during the TanDEM-X Science Phase are presented.

  5. Crustal Deformation Caused by Earthquake Detected by InSAR Technique Using ALOS/PALSAR Data

    Science.gov (United States)

    Miyagi, Y.; Nishimura, Y.; Takahashi, H.; Shimada, M.

    2007-12-01

    The Japan Aerospace Exploration Agency (JAXA) launched the Advanced Land Observing Satellite (ALOS), which is commonly called 'Daichi' in Japanese, on 24th January 2006. This satellite has the Phased Array type L- band Synthetic Aperture Radar (PALSAR) following the mission of the Japanese Earth Resource Satellite-1 (JERS-1). The PALSAR is an advanced SAR sensor with up to 10 m of spatial resolution and variable off-nadir angle. The ALOS/PALSAR can determine the position and attitude with high accuracy by use of mounted dual frequency GPS system and high precision star trackers, and L-band SAR sensor is suitable to observe even heavily-vegetated area. Therefore it is expected much better coherent SAR images than the JERS-1 and the other previous C-band SAR satellites, and major step forward for InSAR (Interferometric SAR) technique. Actually, several outstanding results from InSAR measurements have been reported for the period after the launch. In 2007, two big earthquakes causing some damages on the periphery occurred in Japan. One is M6.7 Noto Peninsula earthquake on 25th March 2007, and the other is M6.8 off the Chuetsu region earthquake on 16th July 2007. Because both seismic faults inferred from these earthquakes are located at shallow depth beneath the bottom of the sea near the coast, obvious crustal deformation in a land area were detected by PALSAR data. In Japan, there is a dense nation-wide GPS network (GEONET) composed of more than 1200 GPS sites established and operated by Geographical Survey Institute and a lot of seismometers. Similarly GPS and seismometer could detect signals caused by the earthquakes, so these are noticeable cases from the standpoint of a comparison among various kinds of data. A remote sensing technique like the ALOS/PALSAR has advantage to observe and monitor a disaster occurred in a remote location where it is difficult to get and there has been little geophysical observation. In this presentation, we notice the case of

  6. Convolutional Sparse Coding for Static and Dynamic Images Analysis

    Directory of Open Access Journals (Sweden)

    B. A. Knyazev

    2014-01-01

    Full Text Available The objective of this work is to improve performance of static and dynamic objects recognition. For this purpose a new image representation model and a transformation algorithm are proposed. It is examined and illustrated that limitations of previous methods make it difficult to achieve this objective. Static images, specifically handwritten digits of the widely used MNIST dataset, are the primary focus of this work. Nevertheless, preliminary qualitative results of image sequences analysis based on the suggested model are presented.A general analytical form of the Gabor function, often employed to generate filters, is described and discussed. In this research, this description is required for computing parameters of responses returned by our algorithm. The recursive convolution operator is introduced, which allows extracting free shape features of visual objects. The developed parametric representation model is compared with sparse coding based on energy function minimization.In the experimental part of this work, errors of estimating the parameters of responses are determined. Also, parameters statistics and their correlation coefficients for more than 106 responses extracted from the MNIST dataset are calculated. It is demonstrated that these data correspond well with previous research studies on Gabor filters as well as with works on visual cortex primary cells of mammals, in which similar responses were observed. A comparative test of the developed model with three other approaches is conducted; speed and accuracy scores of handwritten digits classification are presented. A support vector machine with a linear or radial basic function is used for classification of images and their representations while principal component analysis is used in some cases to prepare data beforehand. High accuracy is not attained due to the specific difficulties of combining our model with a support vector machine (a 3.99% error rate. However, another method is

  7. Automated movement correction for dynamic PET/CT images: evaluation with phantom and patient data.

    Science.gov (United States)

    Ye, Hu; Wong, Koon-Pong; Wardak, Mirwais; Dahlbom, Magnus; Kepe, Vladimir; Barrio, Jorge R; Nelson, Linda D; Small, Gary W; Huang, Sung-Cheng

    2014-01-01

    Head movement during a dynamic brain PET/CT imaging results in mismatch between CT and dynamic PET images. It can cause artifacts in CT-based attenuation corrected PET images, thus affecting both the qualitative and quantitative aspects of the dynamic PET images and the derived parametric images. In this study, we developed an automated retrospective image-based movement correction (MC) procedure. The MC method first registered the CT image to each dynamic PET frames, then re-reconstructed the PET frames with CT-based attenuation correction, and finally re-aligned all the PET frames to the same position. We evaluated the MC method's performance on the Hoffman phantom and dynamic FDDNP and FDG PET/CT images of patients with neurodegenerative disease or with poor compliance. Dynamic FDDNP PET/CT images (65 min) were obtained from 12 patients and dynamic FDG PET/CT images (60 min) were obtained from 6 patients. Logan analysis with cerebellum as the reference region was used to generate regional distribution volume ratio (DVR) for FDDNP scan before and after MC. For FDG studies, the image derived input function was used to generate parametric image of FDG uptake constant (Ki) before and after MC. Phantom study showed high accuracy of registration between PET and CT and improved PET images after MC. In patient study, head movement was observed in all subjects, especially in late PET frames with an average displacement of 6.92 mm. The z-direction translation (average maximum = 5.32 mm) and x-axis rotation (average maximum = 5.19 degrees) occurred most frequently. Image artifacts were significantly diminished after MC. There were significant differences (Pdynamic brain FDDNP and FDG PET/CT scans could improve the qualitative and quantitative aspects of images of both tracers.

  8. A port-Hamiltonian approach to image-based visual servo control for dynamic systems

    NARCIS (Netherlands)

    Mahony, R.; Stramigioli, Stefano

    2012-01-01

    This paper introduces a port-Hamiltonian framework for the design of image-based visual servo control for dynamic mechanical systems. The approach taken introduces the concept of an image effort and provides an interpretation of energy exchange between the dynamics of the physical system and virtual

  9. Fast Simulation of Dynamic Ultrasound Images Using the GPU.

    Science.gov (United States)

    Storve, Sigurd; Torp, Hans

    2017-10-01

    Simulated ultrasound data is a valuable tool for development and validation of quantitative image analysis methods in echocardiography. Unfortunately, simulation time can become prohibitive for phantoms consisting of a large number of point scatterers. The COLE algorithm by Gao et al. is a fast convolution-based simulator that trades simulation accuracy for improved speed. We present highly efficient parallelized CPU and GPU implementations of the COLE algorithm with an emphasis on dynamic simulations involving moving point scatterers. We argue that it is crucial to minimize the amount of data transfers from the CPU to achieve good performance on the GPU. We achieve this by storing the complete trajectories of the dynamic point scatterers as spline curves in the GPU memory. This leads to good efficiency when simulating sequences consisting of a large number of frames, such as B-mode and tissue Doppler data for a full cardiac cycle. In addition, we propose a phase-based subsample delay technique that efficiently eliminates flickering artifacts seen in B-mode sequences when COLE is used without enough temporal oversampling. To assess the performance, we used a laptop computer and a desktop computer, each equipped with a multicore Intel CPU and an NVIDIA GPU. Running the simulator on a high-end TITAN X GPU, we observed two orders of magnitude speedup compared to the parallel CPU version, three orders of magnitude speedup compared to simulation times reported by Gao et al. in their paper on COLE, and a speedup of 27000 times compared to the multithreaded version of Field II, using numbers reported in a paper by Jensen. We hope that by releasing the simulator as an open-source project we will encourage its use and further development.

  10. Monitoring Subsidence in California with InSAR

    Science.gov (United States)

    Farr, T. G.; Jones, C. E.; Liu, Z.; Neff, K. L.; Gurrola, E. M.; Manipon, G.

    2016-12-01

    Subsidence caused by groundwater pumping in the rich agricultural area of California's Central Valley has been a problem for decades. Over the last few years, interferometric synthetic aperture radar (InSAR) observations from satellite and aircraft platforms have been used to produce maps of subsidence with cm accuracy. We are continuing work reported previously, using ESA's Sentinel-1 to extend our maps of subsidence in time and space, in order to eventually cover all of California. The amount of data to be processed has expanded exponentially in the course of our work and we are now transitioning to the use of the ARIA project at JPL to produce the time series. ARIA processing employs large Amazon cloud instances to process single or multiple frames each, scaling from one to many (20+) instances working in parallel to meet the demand (700 GB InSAR products within 3 hours). The data are stored in Amazon long-term storage and an http view of the products are available for users of the ARIA system to download the products. Higher resolution InSAR data were also acquired along the California Aqueduct by the NASA UAVSAR from 2013 - 2016. Using multiple scenes acquired by these systems, we are able to produce time series of subsidence at selected locations and transects showing how subsidence varies both spatially and temporally. The maps show that subsidence is continuing in areas with a history of subsidence and that the rates and areas affected have increased due to increased groundwater extraction during the extended western US drought. Our maps also identify and quantify new, localized areas of accelerated subsidence. The California Department of Water Resources (DWR) funded this work to provide the background and an update on subsidence in the Central Valley to support future policy. Geographic Information System (GIS) files are being furnished to DWR for further analysis of the 4 dimensional subsidence time-series maps. Part of this work was carried out at the

  11. Dynamics of Stability of Orientation Maps Recorded with Optical Imaging.

    Science.gov (United States)

    Shumikhina, S I; Bondar, I V; Svinov, M M

    2018-03-15

    Orientation selectivity is an important feature of visual cortical neurons. Optical imaging of the visual cortex allows for the generation of maps of orientation selectivity that reflect the activity of large populations of neurons. To estimate the statistical significance of effects of experimental manipulations, evaluation of the stability of cortical maps over time is required. Here, we performed optical imaging recordings of the visual cortex of anesthetized adult cats. Monocular stimulation with moving clockwise square-wave gratings that continuously changed orientation and direction was used as the mapping stimulus. Recordings were repeated at various time intervals, from 15 min to 16 h. Quantification of map stability was performed on a pixel-by-pixel basis using several techniques. Map reproducibility showed clear dynamics over time. The highest degree of stability was seen in maps recorded 15-45 min apart. Averaging across all time intervals and all stimulus orientations revealed a mean shift of 2.2 ± 0.1°. There was a significant tendency for larger shifts to occur at longer time intervals. Shifts between 2.8° (mean ± 2SD) and 5° were observed more frequently at oblique orientations, while shifts greater than 5° appeared more frequently at cardinal orientations. Shifts greater than 5° occurred rarely overall (5.4% of cases) and never exceeded 11°. Shifts of 10-10.6° (0.7%) were seen occasionally at time intervals of more than 4 h. Our findings should be considered when evaluating the potential effect of experimental manipulations on orientation selectivity mapping studies. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  12. InSAR remote sensing for performance monitoring of transportation infrastructure at the network level.

    Science.gov (United States)

    2016-01-11

    The goal of the project was the implementation of interferometric synthetic aperture radar : (InSAR) monitoring techniques to allow for early detection of geohazard, potentially : affecting the transportation infrastructure, as well as the monitoring...

  13. Block-like plate movements in eastern Anatolia observed by InSAR

    KAUST Repository

    Cavalie, Olivier; Jonsson, Sigurjon

    2014-01-01

    The question whether continental plates deform internally or move as rigid blocks has been debated for several decades. To further address this question, we use large-scale interferometric synthetic aperture radar (InSAR) data sets to study how

  14. Dynamic MR imaging of liver lesions with superparamagnetic iron oxide (SH-U-555A)

    International Nuclear Information System (INIS)

    Saito, Kazuhiro; Ishida, Jiro; Ito, Naoki; Kakizaki, Dai; Abe, Kimihiko; Kotake, Fumio

    2001-01-01

    Dynamic MRI with SH-U-555 (SPIO) was evaluated. Dynamic MRI was performed for 17 patients with 22 lesions. Dynamic study with T2 * -weighted imaging (T2 * dynamic) and T1-weighted imaging (T1 dynamic) were performed in 8 cases (10 lesions) and 9 cases (12 lesion), respectively. T2 * dynamic MR images were obtained before and 30, 90, 180, 270, 360, and 450 seconds and 31 minutes after the intravenous injection of SPIO, and T1 dynamic MR images were obtained before and 0, 40, 80, 120, 180, 240, 300, 360, 420, 480 seconds and 28 minutes after the injection of SPIO. The signal intensity of each lesion was measured before and after the injection of SPIO. The enhancement ratio of the lesions was calculated and evaluated. The enhancement ratio of hypervascular lesions decreased rapidly in the first phase of T2 * dynamic MRI, while that of hypovascular lesions decreased gradually. The enhancement ratio of hypervascular lesions increased in the first phase of T1 dynamic MRI and decreased gradually, while that of hypovascular lesions lacked the increase in the first phase, in contrast to hypervascular lesions. However, the changing of signal intensity could not be recognized on images with T2 * dynamic and T1 dynamic study. In conclusion, quantitative analysis using the enhancement ratio made it possible to anticipate lesion vascularity. (author)

  15. Usefulness of dynamic MR imaging for the evaluation of transcatheter arterial embolization for hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Kyomasu, Yoshinori; Nakayama, Masafumi; Kawakami, Mutsumi; Mashima, Yasuoki; Ichinose, Akira; Endou, Kazuo; Chiba, Kazuo; Tanno, Munehiko; Yamada, Hideo

    1992-01-01

    Thirteen patients with hepatocellular carcinoma (HCC) were studied with dynamic MR imaging in addition to conventional T 1 - and T 2 -weighted and enhanced T 1 -weighted images before and after the treatment of HCC by transcatheter arterial embolization (TAE). Dynamic MR imaging was performed using GRASS (gradient recalled acquisition in the steady state) sequences. The imaging was started at 10 seconds after rapid injection of Gd-diethylenetriaminepentaacetic acid (Gd-DTPA) with 6s breath hold. Thereafter about 12 images were obtained during 6s breath-holding with 20 seconds intervals. On T 1 - and T 2 -weighted images, signal intensity at the tumor tended to increase during the early period after TAE and to decrease later. Intensities of the HCC, however, were heterogeneous. Differentiation among embolic area, necrosis, viable cells and recurrent area, was often difficult only by conventional images. Dynamic GRASS images could clearly demonstrate an embolic area as a region without contrast enhancement. While recurrent tumor could be diagnosed as an area with early enhancement at the arterial phase. Development of the collateral circulation and dominancy of tumor feeding vessels after TAE could also be deduced on dynamic MR images together with enhanced T 1 -weighted images. The dynamic MR imaging was concluded to be a potentially useful procedure for the clinical evaluation of HCC after TAE. (author)

  16. On tear film breakup (TBU): dynamics and imaging.

    Science.gov (United States)

    Braun, Richard J; Driscoll, Tobin A; Begley, Carolyn G; King-Smith, P Ewen; Siddique, Javed I

    2018-06-13

    We report the results of some recent experiments to visualize tear film dynamics. We then study a mathematical model for tear film thinning and tear film breakup (TBU), a term from the ocular surface literature. The thinning is driven by an imposed tear film thinning rate which is input from in vivo measurements. Solutes representing osmolarity and fluorescein are included in the model. Osmolarity causes osmosis from the model ocular surface, and the fluorescein is used to compute the intensity corresponding closely to in vivo observations. The imposed thinning can be either one-dimensional or axisymmetric, leading to streaks or spots of TBU, respectively. For a spatially-uniform (flat) film, osmosis would cease thinning and balance mass lost due to evaporation; for these space-dependent evaporation profiles TBU does occur because osmolarity diffuses out of the TBU into the surrounding tear film, in agreement with previous results. The intensity pattern predicted based on the fluorescein concentration is compared with the computed thickness profiles; this comparison is important for interpreting in vivo observations. The non-dimensionalization introduced leads to insight about the relative importance of the competing processes; it leads to a classification of large vs small TBU regions in which different physical effects are dominant. Many regions of TBU may be considered small, revealing that the flow inside the film has an appreciable influence on fluorescence imaging of the tear film.

  17. Determining tumor blood flow parameters from dynamic image measurements

    Science.gov (United States)

    Libertini, Jessica M.

    2008-11-01

    Many recent cancer treatments focus on preventing angiogenesis, the process by which a tumor promotes the growth of large and efficient capillary beds for the increased nourishment required to support the tumor's rapid growth[l]. To measure the efficacy of these treatments in a timely fashion, there is an interest in using data from dynamic sequences of contrast-enhanced medical imaging, such as MRI and CT, to measure blood flow parameters such as perfusion, permeability-surface-area product, and the relative volumes of the plasma and extracellular-extravascular space. Starting with a two compartment model presented by the radiology community[2], this work challenges the application of a simplification to this problem, which was originally developed to model capillary reuptake[3]. While the primary result of this work is the demonstration of the inaccuracy of this simplification, the remainder of the paper is dedicated to presenting alternative methods for calculating the perfusion and plasma volume coefficients. These methods are applied to model data sets based on real patient data, and preliminary results are presented.

  18. Imaging dynamic redox processes with genetically encoded probes.

    Science.gov (United States)

    Ezeriņa, Daria; Morgan, Bruce; Dick, Tobias P

    2014-08-01

    Redox signalling plays an important role in many aspects of physiology, including that of the cardiovascular system. Perturbed redox regulation has been associated with numerous pathological conditions; nevertheless, the causal relationships between redox changes and pathology often remain unclear. Redox signalling involves the production of specific redox species at specific times in specific locations. However, until recently, the study of these processes has been impeded by a lack of appropriate tools and methodologies that afford the necessary redox species specificity and spatiotemporal resolution. Recently developed genetically encoded fluorescent redox probes now allow dynamic real-time measurements, of defined redox species, with subcellular compartment resolution, in intact living cells. Here we discuss the available genetically encoded redox probes in terms of their sensitivity and specificity and highlight where uncertainties or controversies currently exist. Furthermore, we outline major goals for future probe development and describe how progress in imaging methodologies will improve our ability to employ genetically encoded redox probes in a wide range of situations. This article is part of a special issue entitled "Redox Signalling in the Cardiovascular System." Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Keyhole imaging method for dynamic objects behind the occlusion area

    Science.gov (United States)

    Hao, Conghui; Chen, Xi; Dong, Liquan; Zhao, Yuejin; Liu, Ming; Kong, Lingqin; Hui, Mei; Liu, Xiaohua; Wu, Hong

    2018-01-01

    A method of keyhole imaging based on camera array is realized to obtain the video image behind a keyhole in shielded space at a relatively long distance. We get the multi-angle video images by using a 2×2 CCD camera array to take the images behind the keyhole in four directions. The multi-angle video images are saved in the form of frame sequences. This paper presents a method of video frame alignment. In order to remove the non-target area outside the aperture, we use the canny operator and morphological method to realize the edge detection of images and fill the images. The image stitching of four images is accomplished on the basis of the image stitching algorithm of two images. In the image stitching algorithm of two images, the SIFT method is adopted to accomplish the initial matching of images, and then the RANSAC algorithm is applied to eliminate the wrong matching points and to obtain a homography matrix. A method of optimizing transformation matrix is proposed in this paper. Finally, the video image with larger field of view behind the keyhole can be synthesized with image frame sequence in which every single frame is stitched. The results show that the screen of the video is clear and natural, the brightness transition is smooth. There is no obvious artificial stitching marks in the video, and it can be applied in different engineering environment .

  20. Simplex GPS and InSAR Inversion Software

    Science.gov (United States)

    Donnellan, Andrea; Parker, Jay W.; Lyzenga, Gregory A.; Pierce, Marlon E.

    2012-01-01

    Changes in the shape of the Earth's surface can be routinely measured with precisions better than centimeters. Processes below the surface often drive these changes and as a result, investigators require models with inversion methods to characterize the sources. Simplex inverts any combination of GPS (global positioning system), UAVSAR (uninhabited aerial vehicle synthetic aperture radar), and InSAR (interferometric synthetic aperture radar) data simultaneously for elastic response from fault and fluid motions. It can be used to solve for multiple faults and parameters, all of which can be specified or allowed to vary. The software can be used to study long-term tectonic motions and the faults responsible for those motions, or can be used to invert for co-seismic slip from earthquakes. Solutions involving estimation of fault motion and changes in fluid reservoirs such as magma or water are possible. Any arbitrary number of faults or parameters can be considered. Simplex specifically solves for any of location, geometry, fault slip, and expansion/contraction of a single or multiple faults. It inverts GPS and InSAR data for elastic dislocations in a half-space. Slip parameters include strike slip, dip slip, and tensile dislocations. It includes a map interface for both setting up the models and viewing the results. Results, including faults, and observed, computed, and residual displacements, are output in text format, a map interface, and can be exported to KML. The software interfaces with the QuakeTables database allowing a user to select existing fault parameters or data. Simplex can be accessed through the QuakeSim portal graphical user interface or run from a UNIX command line.

  1. Fusion of multimodal medical images. Application to dynamic tri dimensional study of vertebral column

    International Nuclear Information System (INIS)

    Brunie, L.

    1992-12-01

    The object of this thesis is to put in correspondence images coming from different ways. The area of application is biomedical imaging, particularly dynamic imaging in three dimensional calculations of spinal cord. The use of computers allows modeling. Then a study of validation by clinical experimentation on spinal cord proves the efficiency of the simulation

  2. Variability induced by the MR imager in dynamic contrast-enhanced imaging of the prostate.

    Science.gov (United States)

    Brunelle, S; Zemmour, C; Bratan, F; Mège-Lechevallier, F; Ruffion, A; Colombel, M; Crouzet, S; Sarran, A; Rouvière, O

    2018-04-01

    To evaluate the variability induced by the imager in discriminating high-grade (Gleason≥7) prostate cancers (HGC) using dynamic contrast-enhanced MRI. We retrospectively selected 3T MRIs with temporal resolution<10 seconds and comprising T1 mapping from a prospective radiologic-pathologic database of patients treated by prostatectomy. Ktrans, Kep, Ve and Vp were calculated for each lesion seen on MRI using the Weinmann arterial input function (AIF) and three patient-specific AIFs measured in the right and left iliac arteries in pixels in the center of the lumen (psAIF-ST) or manually selected by two independent readers (psAIF-R1 and psAIF-R2). A total of 43 patients (mean age, 63.6±4.9 [SD]; range: 48-72 years) with 100 lesions on MRI (55 HGC) were selected. MRIs were performed on imager A (22 patients, 49 lesions) or B (21 patients, 51 lesions) from two different manufacturers. Using the Weinmann AIF, Kep (P=0.005), Ve (P=0.04) and Vp (P=0.01) significantly discriminated HCG. After adjusting on tissue classes, the imager significantly influenced the values of Kep (P=0.049) and Ve (P=0.007). Using patient-specific AIFs, Vp with psAIF-ST (P=0.008) and psAIF-R2 (P=0.04), and Kep with psAIF-R1 (P=0.03) significantly discriminated HGC. After adjusting on tissue classes, types of patient-specific AIF and side of measurement, the imager significantly influenced the values of Ktrans (P=0.0002), Ve (P=0.0072) and Vp (P=0.0003). For all AIFs, the diagnostic value of pharmacokinetic parameters remained unchanged after adjustment on the imager, with stable odds ratios. The imager induced variability in the absolute values of pharmacokinetic parameters but did not change their diagnostic performance. Copyright © 2018 Société française de radiologie. Published by Elsevier Masson SAS. All rights reserved.

  3. Magmatic Activity Beneath the Quiescent Three Sisters Volcanic Center, Central Oregon Cascade Range, USA, Inferred from Satellite InSAR

    Science.gov (United States)

    Wicks, C. W.; Dzurisin, D.; Ingebritsen, S.; Thatcher, W.; Lu, Z.; Iverson, J.

    2001-12-01

    Images from satellite interferometric synthetic aperture radar (InSAR) reveal uplift of a broad ~10 km by 20 km area in the Three Sisters volcanic center of the central Oregon Cascade Range, ~130 km south of Mt. St. Helens. The uplift is centered ~5 km west of South Sister volcano, the youngest stratovolcano in the volcanic center. The center has been volcanically inactive since the last eruption ~1500 years ago. Multiple European Space Agency ERS-1 and 2 satellite images from 1992 through 2000, used in this study, were selected based on orbital separation and time of year. Summer and early autumn scenes were necessary to avoid decorrelation from snow cover. Interferograms generated from these images indicate that most if not all of ~100 mm of observed uplift occurred between September 1998 and October 2000. We interpret the uplift as inflation caused by an apparently ongoing episode of magma intrusion at a depth of ~6.5 km. Geochemical (water chemistry) anomalies, first noted ~1990, coincide with the area of uplift and suggest the existence of a magma reservoir prior to the uplift. High chloride and sulfate concentrations, and a positive correlation between chloride concentration and spring temperature were found within the uplift area, with larger SO4/Cl ratios in springs at higher elevations. These findings are indicative of a high-temperature hydrothermal system driven by magma intrusions. The current inflation episode observed with InSAR may lead to an eruption, but the more persistent geochemical evidence suggests that the episode is likely the latest in a series of hitherto undetected magma intrusions. We do not yet know if the inflation has abated, is continuing, or has accelerated since October 2000--we only know that the highest rate of uplift occurred in the last year for which ERS-2 data was available (1999- 2000). In May of 2001, a continuous GPS receiver and seismometer were installed by the USGS within the Three Sisters Wilderness to monitor the

  4. Controls on slow-moving landslides revealed by satellite and airborne InSAR

    Science.gov (United States)

    Handwerger, Alexander L.; Fielding, Eric J.

    2017-04-01

    Landslides display a wide variety of behaviors ranging from slow persistent motion to rapid acceleration and catastrophic failure. Given the variety of possible behaviors, improvements to our understanding of landslide mechanics are critical for accurate predictions of landslide dynamics. To better constrain the mechanisms that control landslide motion, we use recent SAR data collected by Copernicus Sentinel-1A/B, NASA UAVSAR, JAXA ALOS-2, and DLR TerraSAR-X to quantify the time-dependent kinematics of over 200 slow-moving landslides in the Central and Northern California Coast Ranges. These landslides are ideally suited for InSAR investigations due to their size (up to 5 km in length and 0.5 km in width), persistent downslope motion with low velocities (m/yr), and sparse vegetation. We quantify the seasonal and multi-year changes in velocity driven by changes in precipitation and find that landslide velocity varies over both timescales. Over seasonal timescales, each landslide displays a period of acceleration that occurs within weeks of the onset of seasonal rainfall suggesting that motion is governed by precipitation-induced changes in pore-water pressure. We also examine the effects of multi-year climate variations (i.e., recent historic California drought and the possible wet period that began in late 2016) on the activity of landslides. We find that the drought has led to a decrease in annual displacement over the past several years and predict that a resurgence in annual displacement will occur with an increase in annual rainfall. Lastly, we use UAVSAR data acquired at 4 different look directions to quantify 3D surface displacement of multiple landslides and invert for their subsurface geometry (i.e. basal slip surface) using recently developed 3D mass conservation techniques. The application of NASA's UAVSAR data represents a major advance from previous InSAR studies on landslides in this region and provides one of the first 3D dataset that contains

  5. Caldera deformation in Kyushu island (SW Japan) through InSAR data

    Science.gov (United States)

    Nobile, Adriano; Pepe, Susi; Ruch, Joel; Trippanera, Daniele; Casu, Francesco; Castaldo, Raffaele; Tizzani, Pietro; Aoki, Yosuke; Geshi, Nobuo; Acocella, Valerio; Sansosti, Eugenio; Siniscalchi, Valeria; Borgstrom, Sven; Zoffoli, Simona

    2014-05-01

    Calderas are the surface expression of a long-lived and complex magmatic system, often hosting a shallower hydrothermal system. Most monitored calderas have experienced some forms of unrest, even though only a part of these unrest episodes has culminated in an eruption. This study focuses on surface deformation analysis using InSAR from 1993 to 2013 at two large active calderas, Aso and Aira, located on Kyushu Island (Japan). Despite being closely monitored, our knowledge on the deformation history of both calderas with regard to their activity is poor. ERS, ENVISAT, ALOS and COSMO-SkyMed SAR images have been processed to obtain mean velocity deformation maps and time series through the SBAS technique. Results are then inverted using the simulated annealing technique to evaluate the deformation source parameters. Aso caldera hosts several vents in its central portion. One of these, the Naka Dake crater is the only currently active and erupted 7 times since 1993. From January 1996 to November 1998, after the important 1994 - 1995 eruption, we observed a subsidence of ~1.2 cm/yr at the center of the caldera. Analytical models suggest a deflating source (with various possible shapes) at 5-7 km of depth, implying a magmatic nature for the deformation. Inversion results are consistent with available seismic and GPS data. Aira Caldera hosts the Sakurajima volcano along its southern rim, with a persistent eruptive activity since 1950s. From June 2006 to March 2011, we observed a broad uplift of ~1.5 cm along most of the caldera rim. Analytical inversion of both the entire dataset and a cross-correlated dataset suggests a deformation source at the caldera center, at a depth of 5-9 km (depending on the source shape), implying a magmatic nature of the deformation. Inversion results are in agreement with GPS and InSAR data inversions for other periods of activity. This research has been partially performed within the frame of Italian Space Agency (ASI) and Japan Aerospace

  6. Rapid groundwater-related land subsidence in Yemen observed by multi-temporal InSAR

    Science.gov (United States)

    Abdullin, Ayrat; Xu, Wenbin; Kosmicki, Maximillian; Jonsson, Sigurjon

    2015-04-01

    Several basins in Yemen are suffering from a rapid drawdown of groundwater, which is the most important water source for agricultural irrigation, industry and domestic use. However, detailed geodetic measurements in the region have been lacking and the extent and magnitude of groundwater-related land subsidence has been poorly known. We used 13 ascending ALOS and 15 descending Envisat images to study land subsidence of several basins in Yemen, with a special focus on the Sana'a and Mabar basins. From multitemporal synthetic aperture radar interferometric analysis (persistent scatterers (PS) and small baseline subsets (SBAS)) we examined the spatio-temporal behavior of the subsidence induced by depletion of groundwater aquifer systems from November 2003 to February 2011. In the interferometric data processing, we carefully chose interferogram pairs to minimize spatial and temporal decorrelation, because of high subsidence rates and the type of land cover. Our results show that the spatial pattern of subsidence remained quite stable during the observation period in both the Sana'a and Mabar basins. In the Sana'a basin, the maximum subsidence rate exceeded 14 cm/year in the radar line-of-sight (LOS) direction between 2003 and 2008 in an agricultural area just north of Sana'a city, where water wells have been drying up according to the well data. The subsidence rate was lower in the urban areas, or approximately 1 cm/year, exhibiting annual variations. The main subsidence was found in the center and southern parts of the city, while deformation in the northern part is less obvious. For the Mabar basin, the subsidence rate exceeded 30 cm/year in the agricultural area north of the town of Mabar during 2007 - 2011. The southern part of the Mabar basin also experienced high subsidence rates, although somewhat lower than to the north. Excessive water pumping is the main cause of the ground subsidence and it has already led to extensive ground fracturing at the edge of some

  7. Rapid groundwater-related land subsidence in Yemen observed by multi-temporal InSAR

    KAUST Repository

    Abdullin, Ayrat

    2015-04-01

    Several basins in Yemen are suffering from a rapid drawdown of groundwater, which is the most important water source for agricultural irrigation, industry and domestic use. However, detailed geodetic measurements in the region have been lacking and the extent and magnitude of groundwater-related land subsidence has been poorly known. We used 13 ascending ALOS and 15 descending Envisat images to study land subsidence of several basins in Yemen, with a special focus on the Sana\\'a and Mabar basins. From multitemporal synthetic aperture radar interferometric analysis (persistent scatterers (PS) and small baseline subsets (SBAS)) we examined the spatio-temporal behavior of the subsidence induced by depletion of groundwater aquifer systems from November 2003 to February 2011. In the interferometric data processing, we carefully chose interferogram pairs to minimize spatial and temporal decorrelation, because of high subsidence rates and the type of land cover. Our results show that the spatial pattern of subsidence remained quite stable during the observation period in both the Sana\\'a and Mabar basins. In the Sana\\'a basin, the maximum subsidence rate exceeded 14 cm/year in the radar line-of-sight (LOS) direction between 2003 and 2008 in an agricultural area just north of Sana\\'a city, where water wells have been drying up according to the well data. The subsidence rate was lower in the urban areas, or approximately 1 cm/year, exhibiting annual variations. The main subsidence was found in the center and southern parts of the city, while deformation in the northern part is less obvious. For the Mabar basin, the subsidence rate exceeded 30 cm/year in the agricultural area north of the town of Mabar during 2007 - 2011. The southern part of the Mabar basin also experienced high subsidence rates, although somewhat lower than to the north. Excessive water pumping is the main cause of the ground subsidence and it has already led to extensive ground fracturing at the edge

  8. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies.

    Science.gov (United States)

    Häggström, Ida; Beattie, Bradley J; Schmidtlein, C Ross

    2016-06-01

    To develop and evaluate a fast and simple tool called dpetstep (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. The tool was developed in matlab using both new and previously reported modules of petstep (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). dpetstep was 8000 times faster than MC. Dynamic images from dpetstep had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dpetstep and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dpetstep images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dpetstep to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for studies investigating these phenomena. dpetstep can be downloaded free of cost from https://github.com/CRossSchmidtlein/dPETSTEP.

  9. Monitoring of Three Case Studies of Creeping Landslides in Ecuador using L-band SAR Interferometry (InSAR)

    Science.gov (United States)

    Mayorga Torres, T. M.; Mohseni Aref, M.

    2015-12-01

    Tannia Mayorga Torres1,21 Universidad Central del Ecuador. Faculty of Geology, Mining, Oil, and Environment 2 Hubert H. Humphrey Fellowship 2015-16 IntroductionLandslides lead to human and economic losses across the country, mainly in the winter season. On the other hand, satellite radar data has cost-effective benefits due to open-source software and free availability of data. With the purpose of establishing an early warning system of landslide-related surface deformation, three case studies were designed in the Coast, Sierra (Andean), and Oriente (jungle) regions. The objective of this work was to assess the capability of L-band InSAR to get phase information. For the calculation of the interferograms in Repeat Orbit Interferometry PACkage, the displacement was detected as the error and was corrected. The coherence images (Figure 1) determined that L-band is suitable for InSAR processing. Under this frame, as a first approach, the stacking DInSAR technique [1] was applied in the case studies [2]; however, due to lush vegetation and steep topography, it is necessary to apply advanced InSAR techniques [3]. The purpose of the research is to determine a pattern of data acquisition and successful results to understand the spatial and temporal ground movements associated with landslides. The further work consists of establishing landslide inventories to combine phases of SAR images to generate maps of surface deformation in Tumba-San Francisco and Guarumales to compare the results with ground-based measurements to determine the maps' accuracy. References[1] Sandwell D., Price E. (1998). Phase gradient approach to stacking interferograms. Journal of Geophysical Research, Vol. 103, N. B12, pp. 30,183-30,204. [2] Mayorga T., Platzeck G. (2014). Using DInSAR as a tool to detect unstable terrain areas in an Andes region in Ecuador. NH3.5-Blue Poster B298, Vol. 16, EGU2014-16203. Austria. [3] Wasowski J., Bovenga F. (2014). Investigating landslides and unstable slopes with

  10. An analysis of 'obstructive type' renography cases in 99mTc-DTPA renal dynamic imaging

    International Nuclear Information System (INIS)

    Wang Xinhui

    1991-01-01

    99m Tc-DTPA renal dynamic imaging and computed renography were performed in 61 cases. Renal blood perfusion imaging was also performed in some cases. Renography curves, which did not decrease in 20 min on all 61 cases (90 kidneys), are analysed in combination with renal dynamic imaging and renal perfusion imaging. 11 cases (12 kidneys) are only obstructive. 24 cases (32 kidneys) are obstructive and renal function impaired. Other 26 cases (46 kidneys) are renal function impaired or blood perfusion insufficient, but are not obstructive. The result demonstrated that the obstructive type renography may be obstructive or may be renal function impaired or blood supply insufficient. An analysis of renography in combination with renal dynamic imaging and blood perfusion imaging is more accurate than renography alone

  11. Evaluation of endometrial carcinoma by multislice dynamic MR imaging with Turbo FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Asakawa, Mari [Okayama Univ. (Japan). School of Medicine

    1995-04-01

    The purpose of this study was to investigate the usefulness of multislice dynamic MR imaging with Turbo FLASH in assessing myometrial invasion by endometrial carcinoma. Dynamic MR imaging was performed with bolus injection of Gd-DTPA and with 1.5-T Siemens Magnetom imager using Turbo FLASH. Thirty-six endometrial carcinomas were evaluated with pathologic correlation. Junctional zone showed more rapid contrast enhancement effects than myometrium even after menopause. Contrast to noise ratio between junctional zone and endometrial carcinoma was the highest about fifty seconds after bolus injection. Only at that time could the degree of invasion to junctional zone in post-menopausal women whose junctional zones could not be seen on T{sub 2}-weighted images or contrast-enhanced T{sub 1}-weighted images be evaluated correctly. The accuracy in assessing myometrial invasion with T{sub 2}-weighted images, postcontrast T{sub 1}-weighted images, and dynamic MR imaging was 75%, 81% and 89% respectively. Though there was no statistically significant difference, multislice dynamic imaging with Turbo FLASH technique is considered to be a useful imaging method for the pre-operative assessment of myometrial invasion by endometrial carcinoma. (author).

  12. Pre-eruption deformation caused by dike intrusion beneath Kizimen volcano, Kamchatka, Russia, observed by InSAR

    Science.gov (United States)

    Ji, Lingyun; Lu, Zhong; Dzurisin, Daniel; Senyukov, Sergey

    2013-01-01

    Interferometric synthetic aperture radar (InSAR) images reveal a pre-eruption deformation signal at Kizimen volcano, Kamchatka, Russia, where an ongoing eruption began in mid-November, 2010. The previous eruption of this basaltic andesite-to-dacite stratovolcano occurred in 1927–1928. InSAR images from both ascending and descending orbital passes of Envisat and ALOS PALSAR satellites show as much as 6 cm of line-of-sight shortening from September 2008 to September 2010 in a broad area centered at Kizimen. About 20 cm of opening of a nearly vertical dike provides an adequate fit to the surface deformation pattern. The model dike is approximately 14 km long, 10 km high, centered 13 km beneath Kizimen, and strikes NE–SW. Time-series analysis of multi-temporal interferograms indicates that (1) intrusion started sometime between late 2008 and July 2009, (2) continued at a nearly constant rate, and (3) resulted in a volume expansion of 3.2 × 107 m3 by September 2010, i.e., about two months before the onset of the 2010 eruption. Earthquakes located above the tip of the dike accompanied the intrusion. Eventually, magma pressure in the dike exceeded the confining strength of the host rock, triggering the 2010 eruption. Our results provide insight into the intrusion process that preceded an explosive eruption at a Pacific Rim stratovolcano following nearly a century of quiescence, and therefore have implications for monitoring and hazards assessment at similar volcanoes elsewhere.

  13. Dynamic contrast-enhanced MR imaging of endometrial cancer. Optimizing the imaging delay for tumour-myometrium contrast

    International Nuclear Information System (INIS)

    Park, Sung Bin; Moon, Min Hoan; Sung, Chang Kyu; Oh, Sohee; Lee, Young Ho

    2014-01-01

    To investigate the optimal imaging delay time of dynamic contrast-enhanced magnetic resonance (MR) imaging in women with endometrial cancer. This prospective single-institution study was approved by the institutional review board, and informed consent was obtained from the participants. Thirty-five women (mean age, 54 years; age range, 29-66 years) underwent dynamic contrast-enhanced MR imaging with a temporal resolution of 25-40 seconds. The signal intensity difference ratios between the myometrium and endometrial cancer were analyzed to investigate the optimal imaging delay time using single change-point analysis. The optimal imaging delay time for appropriate tumour-myometrium contrast ranged from 31.7 to 268.1 seconds. The median optimal imaging delay time was 91.3 seconds, with an interquartile range of 46.2 to 119.5 seconds. The median signal intensity difference ratios between the myometrium and endometrial cancer were 0.03, with an interquartile range of -0.01 to 0.06, on the pre-contrast MR imaging and 0.20, with an interquartile range of 0.15 to 0.25, on the post-contrast MR imaging. An imaging delay of approximately 90 seconds after initiating contrast material injection may be optimal for obtaining appropriate tumour-myometrium contrast in women with endometrial cancer. (orig.)

  14. A Stereo Dual-Channel Dynamic Programming Algorithm for UAV Image Stitching.

    Science.gov (United States)

    Li, Ming; Chen, Ruizhi; Zhang, Weilong; Li, Deren; Liao, Xuan; Wang, Lei; Pan, Yuanjin; Zhang, Peng

    2017-09-08

    Dislocation is one of the major challenges in unmanned aerial vehicle (UAV) image stitching. In this paper, we propose a new algorithm for seamlessly stitching UAV images based on a dynamic programming approach. Our solution consists of two steps: Firstly, an image matching algorithm is used to correct the images so that they are in the same coordinate system. Secondly, a new dynamic programming algorithm is developed based on the concept of a stereo dual-channel energy accumulation. A new energy aggregation and traversal strategy is adopted in our solution, which can find a more optimal seam line for image stitching. Our algorithm overcomes the theoretical limitation of the classical Duplaquet algorithm. Experiments show that the algorithm can effectively solve the dislocation problem in UAV image stitching, especially for the cases in dense urban areas. Our solution is also direction-independent, which has better adaptability and robustness for stitching images.

  15. Technical Note: Measurement of common carotid artery lumen dynamics using black-blood MR cine imaging.

    Science.gov (United States)

    Dai, Erpeng; Dong, Li; Zhang, Zhe; Li, Lyu; Zhang, Hui; Zhao, Xihai; Wang, Jinnan; Yuan, Chun; Guo, Hua

    2017-03-01

    To demonstrate the feasibility of measuring the common carotid artery (CCA) lumen dynamics using a black-blood cine (BB-cine) imaging method. Motion-sensitized driven-equilibrium (MSDE) prepared spoiled gradient sequence was used for the BB-cine imaging. CCAs of eleven healthy volunteers were studied using this method. Lumen dynamics, including lumen area evolution waveforms and distension values, were measured and evaluated by comparing this method with bright-blood cine (BrB-cine) imaging. Compared with the BrB-cine images, flow artifacts were effectively suppressed in the BB-cine images. BrB-cine images generally show larger lumen areas than BB-cine images. The lumen area waveforms and distension measurements from BB-cine imaging showed smaller variances among different subjects than BrB-cine imaging. The proposed BB-cine imaging technique can suppress the flow artifacts effectively and reduce the partial volume effects from the vessel wall. This might allow more accurate lumen dynamics measurements than traditional BrB-cine imaging, which may further be valuable for investigating biomechanical and functional properties of the cardiovascular system. © 2017 American Association of Physicists in Medicine.

  16. Multi-exposure high dynamic range image synthesis with camera shake correction

    Science.gov (United States)

    Li, Xudong; Chen, Yongfu; Jiang, Hongzhi; Zhao, Huijie

    2017-10-01

    Machine vision plays an important part in industrial online inspection. Owing to the nonuniform illuminance conditions and variable working distances, the captured image tends to be over-exposed or under-exposed. As a result, when processing the image such as crack inspection, the algorithm complexity and computing time increase. Multiexposure high dynamic range (HDR) image synthesis is used to improve the quality of the captured image, whose dynamic range is limited. Inevitably, camera shake will result in ghost effect, which blurs the synthesis image to some extent. However, existed exposure fusion algorithms assume that the input images are either perfectly aligned or captured in the same scene. These assumptions limit the application. At present, widely used registration based on Scale Invariant Feature Transform (SIFT) is usually time consuming. In order to rapidly obtain a high quality HDR image without ghost effect, we come up with an efficient Low Dynamic Range (LDR) images capturing approach and propose a registration method based on ORiented Brief (ORB) and histogram equalization which can eliminate the illumination differences between the LDR images. The fusion is performed after alignment. The experiment results demonstrate that the proposed method is robust to illumination changes and local geometric distortion. Comparing with other exposure fusion methods, our method is more efficient and can produce HDR images without ghost effect by registering and fusing four multi-exposure images.

  17. Development and assessment of transparent soil and particle image velocimetry in dynamic soil-structure interaction

    Science.gov (United States)

    2007-02-01

    This research combines Particle Image Velocimetry (PIV) and transparent soil to investigate the dynamic rigid block and soil interaction. In order to get a low viscosity pore fluid for the transparent soil, 12 different types of chemical solvents wer...

  18. Coastal Ocean Ecosystem Dynamics Imager Pointing Line-of-Sight Solution Development and Testing

    Data.gov (United States)

    National Aeronautics and Space Administration — A stable pointing line of sight solution is developed and tested in support of the Coastal Ocean Ecosystem Dynamics Imager for the GEOstationary Coastal and Air...

  19. Software development for dynamic position emission tomography: Dynamic image analysis (DIA) tool

    International Nuclear Information System (INIS)

    Pyeon, Do Yeong; Jung, Young Jin; Kim, Jung Su

    2016-01-01

    Positron Emission Tomography(PET) is nuclear medical tests which is a combination of several compounds with a radioactive isotope that can be injected into body to quantitatively measure the metabolic rate (in the body). Especially, Phenomena that increase (sing) glucose metabolism in cancer tissue using the 18F-FDG (Fluorodeoxyglucose) is utilized widely in cancer diagnosis. And then, Numerous studies have been reported that incidence seems high availability even in the modern diagnosis of dementia and Parkinson's (disease) in brain disease. When using a dynamic PET image including the time information in the static information that is provided for the diagnosis many can increase the accuracy of diagnosis. For this reason, clinical researchers getting great attention but, it is the lack of tools to conduct research. And, it interfered complex mathematical algorithm and programming skills for activation of research. In this study, in order to easy to use and enable research dPET, we developed the software based graphic user interface(GUI). In the future, by many clinical researcher using DIA-Tool is expected to be of great help to dPET research

  20. Software development for dynamic position emission tomography: Dynamic image analysis (DIA) tool

    Energy Technology Data Exchange (ETDEWEB)

    Pyeon, Do Yeong; Jung, Young Jin [Dongseo University, Busan (Korea, Republic of); Kim, Jung Su [Dept. of Radilogical Science, Dongnam Health University, Suwon (Korea, Republic of)

    2016-09-15

    Positron Emission Tomography(PET) is nuclear medical tests which is a combination of several compounds with a radioactive isotope that can be injected into body to quantitatively measure the metabolic rate (in the body). Especially, Phenomena that increase (sing) glucose metabolism in cancer tissue using the 18F-FDG (Fluorodeoxyglucose) is utilized widely in cancer diagnosis. And then, Numerous studies have been reported that incidence seems high availability even in the modern diagnosis of dementia and Parkinson's (disease) in brain disease. When using a dynamic PET image including the time information in the static information that is provided for the diagnosis many can increase the accuracy of diagnosis. For this reason, clinical researchers getting great attention but, it is the lack of tools to conduct research. And, it interfered complex mathematical algorithm and programming skills for activation of research. In this study, in order to easy to use and enable research dPET, we developed the software based graphic user interface(GUI). In the future, by many clinical researcher using DIA-Tool is expected to be of great help to dPET research.

  1. InSAR Analysis of Post-Seismic Deformation Following the 2013 Mw 7.7 Balochistan, Pakistan Earthquake

    Science.gov (United States)

    Peterson, K.; Barnhart, W. D.

    2017-12-01

    On September 24th, 2013, a Mw 7.7 earthquake ruptured a 200 km portion of the Hoshab fault, a reverse fault in the Makran accretionary prism of southern Pakistan. This earthquake is notable because it ruptured a reverse fault with a predominantly strike-slip sense of displacement, and it ruptured a mechanically weak accretionary prism. Here, we present initial analysis of ongoing post-seismic deformation imaged with the Sentinel-1 interferometric synthetic aperture radar (InSAR) mission with the goals of a) determining the dominant post-seismic deformation processes active, b) characterizing the rigidity and rheological structure of a flat-slab subduction zone, and c) elucidating whether post-seismic deformation may account for or exacerbate the 4-6 m fault convergence deficit left by the 2013 earthquake. We first present InSAR time series analysis of the post-seismic transient derived from ongoing Sentinel-1 SAR acquisitions, including a comparison of atmosphere-corrected and uncorrected time series. Interferograms spanning December 2014 to the present reveal an ongoing post-seismic deformation transient in the region surrounding the Hoshab fault. Additionally, fault creep signals on and adjacent to the Hoshab fault are present. Second, we present a suite of forward models that explore the potential contributions of viscoelastic relaxation and frictional afterslip to the recorded displacement signal. These models, conducted using the semi-analytical solutions of RELAX and compared to InSAR line-of-sight time series displacements, explore a range of candidate rheological descriptions of the Makran subduction zone that are designed to probe the rheological structure of a region where current knowledge of the subsurface geology is highly limited. Our preliminary results suggest that post-seismic displacements arise from a combination of viscoelastic deformation and frictional afterslip, as opposed to one single mechanism. Additionally, our preliminary results suggest

  2. Volcano-tectonic interactions at Sabancaya and other Peruvian volcanoes revealed by InSAR and seismicity

    Science.gov (United States)

    Jay, J.; Pritchard, M. E.; Aron, F.; Delgado, F.; Macedo, O.; Aguilar, V.

    2013-12-01

    An InSAR survey of all 13 Holocene volcanoes in the Andean Central Volcanic Zone of Peru reveals previously undocumented surface deformation that is occasionally accompanied by seismic activity. Our survey utilizes SAR data spanning from 1992 to the present from the ERS-1, ERS-2, and Envisat satellites, as well as selected data from the TerraSAR-X satellite. We find that the recent unrest at Sabancaya volcano (heightened seismicity since 22 February 2013 and increased fumarolic output) has been accompanied by surface deformation. We also find two distinct deformation episodes near Sabancaya that are likely associated with an earthquake swarm in February 2013 and a M6 normal fault earthquake that occurred on 17 July 2013. Preliminary modeling suggests that faulting from the observed seismic moment can account for nearly all of the observed deformation and thus we have not yet found clear evidence for recent magma intrusion. We also document an earlier episode of deformation that occurred between December 2002 and September 2003 which may be associated with a M5.3 earthquake that occurred on 13 December 2002 on the Solarpampa fault, a large EW-striking normal fault located about 25 km northwest of Sabancaya volcano. All of the deformation episodes between 2002 and 2013 are spatially distinct from the inflation seen near Sabancaya from 1992 to 1997. In addition to the activity at Sabancaya, we also observe deformation near Coropuna volcano, in the Andagua Valley, and in the region between Ticsani and Tutupaca volcanoes. InSAR images reveal surface deformation that is possibly related to an earthquake swarm near Coropuna and Sabancaya volcanoes in December 2001. We also find persistent deformation in the scoria cone and lava field along the Andagua Valley, located 40 km east of Corpuna. An earthquake swarm near Ticsani volcano in 2005 produced surface deformation centered northwest of the volcano and was accompanied by a north-south elongated subsidence signal to the

  3. The diagnostic value of adding dynamic scintigraphy to standard delayed planar imaging for sentinel node identification in melanoma patients

    DEFF Research Database (Denmark)

    Nielsen, Marie Kristina Rue; Chakera, Annette H; Hesse, Birger

    2011-01-01

    The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients.......The aim of this study was to compare early dynamic imaging combined with delayed static imaging and single photon emission computed tomography (SPECT)/CT with delayed, planar, static imaging alone for sentinel node (SN) identification in melanoma patients....

  4. Recent advances in photorefractivity of poly(4-diphenylaminostyrene) composites: Wavelength dependence and dynamic holographic images

    Science.gov (United States)

    Tsujimura, Sho; Kinashi, Kenji; Sakai, Wataru; Tsutsumi, Naoto

    2014-08-01

    To expand upon our previous report [Appl. Phys. Express 5, 064101 (2012) 064101], we provide here the modified poly(4-diphenylaminostyrene) (PDAS)-based photorefractive (PR) device on the basis of wavelength dependency, and demonstrate dynamic holographic images by using the PDAS-based PR device under the obtained appropriate conditions. The PR devices containing the triphenylamine unit have potential application to dynamic holographic images, which will be useful for real-time holographic displays.

  5. Image communication scheme based on dynamic visual cryptography and computer generated holography

    Science.gov (United States)

    Palevicius, Paulius; Ragulskis, Minvydas

    2015-01-01

    Computer generated holograms are often exploited to implement optical encryption schemes. This paper proposes the integration of dynamic visual cryptography (an optical technique based on the interplay of visual cryptography and time-averaging geometric moiré) with Gerchberg-Saxton algorithm. A stochastic moiré grating is used to embed the secret into a single cover image. The secret can be visually decoded by a naked eye if only the amplitude of harmonic oscillations corresponds to an accurately preselected value. The proposed visual image encryption scheme is based on computer generated holography, optical time-averaging moiré and principles of dynamic visual cryptography. Dynamic visual cryptography is used both for the initial encryption of the secret image and for the final decryption. Phase data of the encrypted image are computed by using Gerchberg-Saxton algorithm. The optical image is decrypted using the computationally reconstructed field of amplitudes.

  6. Progress and monitoring system on compression and transmission technologies of dynamic image

    International Nuclear Information System (INIS)

    Kobayashi, Hiroyuki; Saijo, Nobuyuki; Nakajo, Ken

    2001-01-01

    The Toshiba Corporation developed a real-time dynamic image transmission matched with quality of transmission circuit by using MPEG-4 which was recent international standard system for the dynamic image coding system. Concretely, this system made possible on real-time dynamic image transmission even at transmission on wireless circuit such as portable telephone, PHS, wireless LAN, and so on, at viewpoint of the mobile communication. And, by using the wireless circuit, it could be built without any limit of transmission cable, to realize its layout-free establishment. In addition, this system uses only image for communication without using voice, and some devices were carried out to upgrade image and frame speed as possible. Here were described on outlines of transmission system and principle of detection MPEG-4, and function and application of monitoring system using this system. (G.K.)

  7. Some applications of nonlinear diffusion to processing of dynamic evolution images

    International Nuclear Information System (INIS)

    Goltsov, Alexey N.; Nikishov, Sergey A.

    1997-01-01

    Model nonlinear diffusion equation with the most simple Landau-Ginzburg free energy functional was applied to locate boundaries between meaningful regions of low-level images. The method is oriented to processing images of objects that are a result of dynamic evolution: images of different organs and tissues obtained by radiography and NMR methods, electron microscope images of morphogenesis fields, etc. In the methods developed by us, parameters of the nonlinear diffusion model are chosen on the basis of the preliminary treatment of the images. The parameters of the Landau-Ginzburg free energy functional are extracted from the structure factor of the images. Owing to such a choice of the model parameters, the image to be processed is located in the vicinity of the steady-state of the diffusion equation. The suggested method allows one to separate distinct structures having specific space characteristics from the whole image. The method was applied to processing X-ray images of the lung

  8. Development and validation of factor analysis for dynamic in-vivo imaging data sets

    Science.gov (United States)

    Goldschmied, Lukas; Knoll, Peter; Mirzaei, Siroos; Kalchenko, Vyacheslav

    2018-02-01

    In-vivo optical imaging method provides information about the anatomical structures and function of tissues ranging from single cell to entire organisms. Dynamic Fluorescent Imaging (DFI) is used to examine dynamic events related to normal physiology or disease progression in real time. In this work we improve this method by using factor analysis (FA) to automatically separate overlying structures.The proposed method is based on a previously introduced Transcranial Optical Vascular Imaging (TOVI), which employs natural and sufficient transparency through the intact cranial bones of a mouse. Fluorescent image acquisition is performed after intravenous fluorescent tracer administration. Afterwards FA is used to extract structures with different temporal characteristics from dynamic contrast enhanced studies without making any a priori assumptions about physiology. The method was validated by a dynamic light phantom based on the Arduino hardware platform and dynamic fluorescent cerebral hemodynamics data sets. Using the phantom data FA can separate various light channels without user intervention. FA applied on an image sequence obtained after fluorescent tracer administration is allowing extracting valuable information about cerebral blood vessels anatomy and functionality without a-priory assumptions of their anatomy or physiology while keeping the mouse cranium intact. Unsupervised color-coding based on FA enhances visibility and distinguishing of blood vessels belonging to different compartments. DFI based on FA especially in case of transcranial imaging can be used to separate dynamic structures.

  9. Remote Histology Learning from Static versus Dynamic Microscopic Images

    Science.gov (United States)

    Mione, Sylvia; Valcke, Martin; Cornelissen, Maria

    2016-01-01

    Histology is the study of microscopic structures in normal tissue sections. Curriculum redesign in medicine has led to a decrease in the use of optical microscopes during practical classes. Other imaging solutions have been implemented to facilitate remote learning. With advancements in imaging technologies, learning material can now be digitized.…

  10. Utilization of InSAR differential interferometry for surface deformation detection caused by mining

    International Nuclear Information System (INIS)

    Yang, F.; Shao, Y.; Guichen, M.

    2010-01-01

    In China, the surface deformation of ground has been a significant geotechnical problem as a result of cracks in the ground surface, collapsing of house, and subsidence of roads. A powerful technology for detecting surface deformation in the ground is differential interferometry using synthetic aperture radar (INSAR). The technology enables the analysis from different phase of micro-wave between two observed data by synthetic aperture radar (SAR) of surface deformation of ground such as ground subsidence, land slide, and slope failure. In January 2006, the advanced land observing satellite was launched by the Japan Aerospace Exploration Agency. This paper presented an analytical investigation to detect ground subsidence or change caused by mining, overuse of ground water, and disaster. Specifically, the paper discussed the INSAR monitoring technology of the mine slope, including INSAR data sources and processing software; the principle of synthetic aperture radar interferometry; principles of differential SAR interferometry; and INSAR technology to slope monitoring of the Haizhou open pit mine. The paper also discussed the Haizhou strip mine side slope INSAR monitoring results and tests. It was concluded that the use of synthetic aperture radar interferometer technique was the optimal technique to provide three-dimensional spatial information and minimal change from ground surface by spatial remote sensing device. 18 refs., 5 figs.

  11. PRECURSORY SLOPE DEFORMATION AROUND LANDSLIDE AREA DETECTED BY INSAR THROUGHOUT JAPAN

    Directory of Open Access Journals (Sweden)

    T. Nakano

    2016-06-01

    Full Text Available Interferometric Synthetic Aperture Radar (InSAR technique is able to detect a slope deformation around landslide (e.g., Singhroy et al., 2004; Une et al., 2008; Riedel and Walther, 2008; Sato et al., 2014. Geospatial Information Authority (GSI of Japan has been performing the InSAR analysis regularly by using ALOS/PALSAR data and ALOS-2/PALSAR-2 data throughout Japan. There are a lot of small phase change sites except for crustal deformation with earthquake or volcano activity in the InSAR imagery. Most of the phase change sites are located in landslide area. We conducted field survey at the 10 sites of those phase change sites. As a result, we identified deformation of artificial structures or linear depressions caused by mass movement at the 9 sites. This result indicates that InSAR technique can detect on the continual deformation of landslide block for several years. GSI of Japan will continue to perform the InSAR analysis throughout Japan. Therefore, we will be able to observe and monitor precursory slope deformation around landslide areas throughout Japan.

  12. Utilization of InSAR differential interferometry for surface deformation detection caused by mining

    Energy Technology Data Exchange (ETDEWEB)

    Yang, F. [Liaoning Technical Univ., Fuxin (China). School of Geomatics; Shao, Y. [Liaoning Technical Univ., Fuxin (China). Dept. of Foreign Language; Guichen, M. [Gifu Univ., Yanagido, Gifu (Japan). Dept. of Civil Engineering

    2010-07-01

    In China, the surface deformation of ground has been a significant geotechnical problem as a result of cracks in the ground surface, collapsing of house, and subsidence of roads. A powerful technology for detecting surface deformation in the ground is differential interferometry using synthetic aperture radar (INSAR). The technology enables the analysis from different phase of micro-wave between two observed data by synthetic aperture radar (SAR) of surface deformation of ground such as ground subsidence, land slide, and slope failure. In January 2006, the advanced land observing satellite was launched by the Japan Aerospace Exploration Agency. This paper presented an analytical investigation to detect ground subsidence or change caused by mining, overuse of ground water, and disaster. Specifically, the paper discussed the INSAR monitoring technology of the mine slope, including INSAR data sources and processing software; the principle of synthetic aperture radar interferometry; principles of differential SAR interferometry; and INSAR technology to slope monitoring of the Haizhou open pit mine. The paper also discussed the Haizhou strip mine side slope INSAR monitoring results and tests. It was concluded that the use of synthetic aperture radar interferometer technique was the optimal technique to provide three-dimensional spatial information and minimal change from ground surface by spatial remote sensing device. 18 refs., 5 figs.

  13. Dynamic measurements of flowing cells labeled by gold nanoparticles using full-field photothermal interferometric imaging

    Science.gov (United States)

    Turko, Nir A.; Roitshtain, Darina; Blum, Omry; Kemper, Björn; Shaked, Natan T.

    2017-06-01

    We present highly dynamic photothermal interferometric phase microscopy for quantitative, selective contrast imaging of live cells during flow. Gold nanoparticles can be biofunctionalized to bind to specific cells, and stimulated for local temperature increase due to plasmon resonance, causing a rapid change of the optical phase. These phase changes can be recorded by interferometric phase microscopy and analyzed to form an image of the binding sites of the nanoparticles in the cells, gaining molecular specificity. Since the nanoparticle excitation frequency might overlap with the sample dynamics frequencies, photothermal phase imaging was performed on stationary or slowly dynamic samples. Furthermore, the computational analysis of the photothermal signals is time consuming. This makes photothermal imaging unsuitable for applications requiring dynamic imaging or real-time analysis, such as analyzing and sorting cells during fast flow. To overcome these drawbacks, we utilized an external interferometric module and developed new algorithms, based on discrete Fourier transform variants, enabling fast analysis of photothermal signals in highly dynamic live cells. Due to the self-interference module, the cells are imaged with and without excitation in video-rate, effectively increasing signal-to-noise ratio. Our approach holds potential for using photothermal cell imaging and depletion in flow cytometry.

  14. Maximum a posteriori reconstruction of the Patlak parametric image from sinograms in dynamic PET

    International Nuclear Information System (INIS)

    Wang Guobao; Fu Lin; Qi Jinyi

    2008-01-01

    Parametric imaging using the Patlak graphical method has been widely used to analyze dynamic PET data. Conventionally a Patlak parametric image is generated by reconstructing a sequence of dynamic images first and then performing Patlak graphical analysis on the time-activity curves pixel-by-pixel. However, because it is rather difficult to model the noise distribution in reconstructed images, the spatially variant noise correlation is simply ignored in the Patlak analysis, which leads to sub-optimal results. In this paper we present a Bayesian method for reconstructing Patlak parametric images directly from raw sinogram data by incorporating the Patlak plot model into the image reconstruction procedure. A preconditioned conjugate gradient algorithm is used to find the maximum a posteriori solution. The proposed direct method is statistically more efficient than the conventional indirect approach because the Poisson noise distribution in PET data can be accurately modeled in the direct reconstruction. The computation cost of the direct method is similar to reconstruction time of two dynamic frames. Therefore, when more than two dynamic frames are used in the Patlak analysis, the direct method is faster than the conventional indirect approach. We conduct computer simulations to validate the proposed direct method. Comparisons with the conventional indirect approach show that the proposed method results in a more accurate estimate of the parametric image. The proposed method has been applied to dynamic fully 3D PET data from a microPET scanner

  15. Confined aquifer head measurements and storage properties in the San Luis Valley, Colorado, from spaceborne InSAR observations

    Science.gov (United States)

    Chen, Jingyi; Knight, Rosemary; Zebker, Howard A.; Schreüder, Willem A.

    2016-05-01

    Interferometric Synthetic Aperture Radar (InSAR), a remote sensing technique for measuring centimeter-level surface deformation, is used to estimate hydraulic head in the confined aquifer of the San Luis Valley (SLV), Colorado. Reconstructing head measurements from InSAR in agricultural regions can be difficult, as InSAR phase data are often decorrelated due to vegetation growth. Analysis of 17 L-band ALOS PALSAR scenes, acquired between January 2007 and March 2011, demonstrates that comprehensive InSAR deformation measurements can be recovered over the vegetated groundwater basin with an improved processing strategy. Local skeletal storage coefficients and time delays between the head change and deformation are estimated through a joint InSAR-well data analysis. InSAR subsidence estimates are transformed to head changes with finer temporal and spatial resolution than is possible using existing well records alone. Both InSAR and well data suggest that little long-term water-storage loss occurred in the SLV over the study period and that inelastic compaction was negligible. The seasonal head variations derived from InSAR are consistent with the existing well data at most locations where confined aquifer pumping activity dominates. Our results demonstrate the advantages of InSAR measurements for basin-wide characterization of aquifer storage properties and groundwater levels over agricultural regions.

  16. Estimation of vessel diameter and blood flow dynamics from laser speckle images

    DEFF Research Database (Denmark)

    Postnov, Dmitry D.; Tuchin, Valery V.; Sosnovtseva, Olga

    2016-01-01

    Laser speckle imaging is a rapidly developing method to study changes of blood velocity in the vascular networks. However, to assess blood flow and vascular responses it is crucial to measure vessel diameter in addition to blood velocity dynamics. We suggest an algorithm that allows for dynamical...

  17. Dynamic magnetic resonance imaging before and 6 months after laparoscopic sacrocolpopexy

    NARCIS (Netherlands)

    Weiden, R.M.F. van der; Rociu, E.; Mannaerts, G.H.; Hooff, M.H. van; Vierhout, M.E.; Withagen, M.I.J.

    2014-01-01

    INTRODUCTION AND HYPOTHESIS: The objective of this study was to correlate dynamic magnetic resonance imaging (MRI) with Pelvic Organ Prolapse Quantification (POP-Q) measurements and pelvic floor symptoms in order to determine the value of dynamic MRI for evaluating vaginal vault prolapse both before

  18. Imaging of propagation dynamics of optically-excited spin waves in a garnet film

    International Nuclear Information System (INIS)

    Hashimoto, Yusuke; Saitoh, Eiji

    2016-01-01

    We demonstrate the direct imaging of the propagation dynamics of the optically-excited spin waves in a garnet film observed with an all-optical pump-and-probe magneto-optical imaging technique having sub-pico second time-resolution, sub-micrometer spatial resolution, and milli-degrees of accuracy in the rotation angle of the light polarization. (author)

  19. Pseudorandom numbers: evolutionary models in image processing, biology, and nonlinear dynamic systems

    Science.gov (United States)

    Yaroslavsky, Leonid P.

    1996-11-01

    We show that one can treat pseudo-random generators, evolutionary models of texture images, iterative local adaptive filters for image restoration and enhancement and growth models in biology and material sciences in a unified way as special cases of dynamic systems with a nonlinear feedback.

  20. A Hybrid Shared-Memory Parallel Max-Tree Algorithm for Extreme Dynamic-Range Images

    NARCIS (Netherlands)

    Moschini, Ugo; Meijster, Arnold; Wilkinson, Michael

    Max-trees, or component trees, are graph structures that represent the connected components of an image in a hierarchical way. Nowadays, many application fields rely on images with high-dynamic range or floating point values. Efficient sequential algorithms exist to build trees and compute

  1. Forest biomass mapping from fusion of GEDI Lidar data and TanDEM-X InSAR data

    Science.gov (United States)

    Qi, W.; Hancock, S.; Armston, J.; Marselis, S.; Dubayah, R.

    2017-12-01

    Mapping forest above-ground biomass (hereafter biomass) can significantly improve our ability to assess the role of forest in terrestrial carbon budget and to analyze the ecosystem productivity. Global Ecosystem Dynamic Investigation (GEDI) mission will provide the most complete lidar observations of forest vertical structure and has the potential to provide global-scale forest biomass data at 1-km resolution. However, GEDI is intrinsically a sampling mission and will have a between-track spacing of 600 m. An increase in adjacent-swath distance and the presence of cloud cover may also lead to larger gaps between GEDI tracks. In order to provide wall-to-wall forest biomass maps, fusion algorithms of GEDI lidar data and TanDEM-X InSAR data were explored in this study. Relationship between biomass and lidar RH metrics was firstly developed and used to derive biomass values over GEDI tracks which were simulated using airborne lidar data. These GEDI biomass values were then averaged in each 1-km cell to represent the biomass density within that cell. Whereas for cells without any GEDI observations, regression models developed between GEDI-derived biomass and TDX InSAR variables were applied to predict biomass over those places. Based on these procedures, contiguous biomass maps were finally generated at 1-km resolution over three representative forest types. Uncertainties for these biomass maps were also estimated at 1 km following methods developed in Saarela et al. (2016). Our results indicated great potential of GEDI/TDX fusion for large-scale biomass mapping. Saarela, S., Holm, S., Grafstrom, A., Schnell, S., Naesset, E., Gregoire, T.G., Nelson, R.F., & Stahl, G. (2016). Hierarchical model-based inference for forest inventory utilizing three sources of information. Annals of Forest Science, 73, 895-910

  2. Three-dimensional display and measurement of cardiac dynamic indexes from MR images

    International Nuclear Information System (INIS)

    Kono, M.; Matsuo, M.; Yamasaki, K.; Banno, T.; Toriwaki, J.; Yokoi, S.; Oshita, H.

    1986-01-01

    The cardiac dynamic index, to which such variables as cardiac output, ejection fraction, and wall motion contribute, is routinely determined using various modalities such as angiography, radionuclide imaging, US, and x-ray CT. Each of these modalities, however, has some disadvantages in regard to evaluating the cardiac dynamic index. The authors have obtained precise multidirectional projection images of the heart by means of computer graphics and reformatted data of cardiac MR images obtained with cardiac gating. The contiguous coronal MR images of the heart are made at an interimage distance of 5 mm. In each section, five or six cardiac images can be obtained, depending on the systolic or diastolic phase. These images are stored in a computer, and a three-dimensional display of the heart with biocular observation and with multiplex holograms is made possible with computer graphics. Three-dimensional measurement of the cardiac index is now being attempted, including cardiac output, ejection fraction, and wall motion

  3. Insight into dynamic genome imaging: Canonical framework identification and high-throughput analysis.

    Science.gov (United States)

    Ronquist, Scott; Meixner, Walter; Rajapakse, Indika; Snyder, John

    2017-07-01

    The human genome is dynamic in structure, complicating researcher's attempts at fully understanding it. Time series "Fluorescent in situ Hybridization" (FISH) imaging has increased our ability to observe genome structure, but due to cell type and experimental variability this data is often noisy and difficult to analyze. Furthermore, computational analysis techniques are needed for homolog discrimination and canonical framework detection, in the case of time-series images. In this paper we introduce novel ideas for nucleus imaging analysis, present findings extracted using dynamic genome imaging, and propose an objective algorithm for high-throughput, time-series FISH imaging. While a canonical framework could not be detected beyond statistical significance in the analyzed dataset, a mathematical framework for detection has been outlined with extension to 3D image analysis. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. GEO-CAPE Coastal Ecosystem Dynamics Imager (COEDI) Instrument Design

    Data.gov (United States)

    National Aeronautics and Space Administration — The primary goal of this study is to build a breadboard instrument and prove the functionality of the optical-mechanical assembly for the Coastal Ecosystem Dynamics...

  5. Assessment of pelvic floor dysfunctions using dynamic magnetic resonance imaging

    Directory of Open Access Journals (Sweden)

    Hoda Salah Darwish

    2014-03-01

    Conclusion: Dynamic MRI is an ideal, non invasive technique which does not require patient preparation for evaluation of pelvic floor. It acts as one stop shop for diagnosing single or multiple pelvic compartment involvement in patients with pelvic floor dysfunction.

  6. Curvelet-based compressive sensing for InSAR raw data

    Science.gov (United States)

    Costa, Marcello G.; da Silva Pinho, Marcelo; Fernandes, David

    2015-10-01

    The aim of this work is to evaluate the compression performance of SAR raw data for interferometry applications collected by airborne from BRADAR (Brazilian SAR System operating in X and P bands) using the new approach based on compressive sensing (CS) to achieve an effective recovery with a good phase preserving. For this framework is desirable a real-time capability, where the collected data can be compressed to reduce onboard storage and bandwidth required for transmission. In the CS theory, a sparse unknown signals can be recovered from a small number of random or pseudo-random measurements by sparsity-promoting nonlinear recovery algorithms. Therefore, the original signal can be significantly reduced. To achieve the sparse representation of SAR signal, was done a curvelet transform. The curvelets constitute a directional frame, which allows an optimal sparse representation of objects with discontinuities along smooth curves as observed in raw data and provides an advanced denoising optimization. For the tests were made available a scene of 8192 x 2048 samples in range and azimuth in X-band with 2 m of resolution. The sparse representation was compressed using low dimension measurements matrices in each curvelet subband. Thus, an iterative CS reconstruction method based on IST (iterative soft/shrinkage threshold) was adjusted to recover the curvelets coefficients and then the original signal. To evaluate the compression performance were computed the compression ratio (CR), signal to noise ratio (SNR), and because the interferometry applications require more reconstruction accuracy the phase parameters like the standard deviation of the phase (PSD) and the mean phase error (MPE) were also computed. Moreover, in the image domain, a single-look complex image was generated to evaluate the compression effects. All results were computed in terms of sparsity analysis to provides an efficient compression and quality recovering appropriated for inSAR applications

  7. Dynamic MR imaging of cavernous hemangioma with Gd-DTPA

    International Nuclear Information System (INIS)

    Luning, M.; Wolf, K.J.; Hamm, B.; Dewey, C.; Koch, M.; Taupitz, M.; Schnackenburg, B.; Schneider, T.; Petersein, J.; Muhler, A.; Haustein, J.

    1990-01-01

    This paper evaluates the use of gradient-echo, fast-field-echo (FFE), breathhold MR imaging in The characterization of liver tumors. The authors examined 32 hepatic hemangiomas with a 1.5-T imager using T1-weighted (500/15) and T2-weighted (2,480/100) spin-echo sequences, and multi-echo sequences (2,000/30,60,90...240); also, after intravenous administration of Gd-DTPA (0.2 mmol/kg), gradient-echo, FFE, breathhold images (27/13/60 degrees) were obtained. We evaluated the relationship of peripheral and central enhancement to the size of the lesion in 22 hemangiomas

  8. Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

    KAUST Repository

    Li, Z. W.; Xu, Wenbin; Feng, G. C.; Hu, J.; Wang, C. C.; Ding, X. L.; Zhu, J. J.

    2012-01-01

    The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

  9. Temporal Evolution of Surface Deformation and Magma Sources at Pacaya Volcano, Guatemala Revealed by InSAR

    Science.gov (United States)

    Wnuk, K.; Wauthier, C.

    2016-12-01

    Pacaya Volcano, Guatemala is a persistently active volcano whose western flank is unstable. Despite continuous activity since 1961, a lack of high temporal resolution geodetic surveying has prevented detailed modeling of Pacaya's underlying magmatic plumbing system. A new, temporally dense dataset of Interferometric Synthetic Aperture Radar (InSAR) RADARSAT-2 images, spanning December 2012 to March 2014, shows magmatic deformation before and during major eruptions in January and March 2014. Inverse modeling of InSAR surface displacements suggest that three magma bodies are responsible for observed deformation: (1) a 3.7 km deep spherical reservoir located northwest of the summit, (2) a 0.4 km deep spherical source located directly west of the summit, and (3) a shallow dike below the summit that provides the primary transport pathway for erupted materials. Periods of heightened activity are brought on by magma pulses at depth, which result in rapid inflation of the edifice. We observe an intrusion cycle at Pacaya that consists of deflation of one or both magma reservoirs followed by dike intrusion. Intrusion volumes are proportional to reservoir volume loss, and do not always result in an eruption. Periods of increased activity culminate with larger dike fed eruptions. Large eruptions are followed by inter eruptive periods marked by a decrease in crater explosions and a lack of deformation. A full understanding of magmatic processes at Pacaya is required to assess potential impacts on other aspects of the volcano such as the unstable western flank. Co-eruptive flank motion appears to have initiated a new stage of volcanic rifting at Pacaya defined by repeated NW-SE dike intrusions. This creates a positive feedback relationship whereby magmatic forcing from eruptive dike intrusions induces flank motion

  10. Correcting atmospheric effects on InSAR with MERIS water vapour data and elevation-dependent interpolation model

    KAUST Repository

    Li, Z. W.

    2012-05-01

    The propagation delay when radar signals travel from the troposphere has been one of the major limitations for the applications of high precision repeat-pass Interferometric Synthetic Aperture Radar (InSAR). In this paper, we first present an elevation-dependent atmospheric correction model for Advanced Synthetic Aperture Radar (ASAR—the instrument aboard the ENVISAT satellite) interferograms with Medium Resolution Imaging Spectrometer (MERIS) integrated water vapour (IWV) data. Then, using four ASAR interferometric pairs over Southern California as examples, we conduct the atmospheric correction experiments with cloud-free MERIS IWV data. The results show that after the correction the rms differences between InSAR and GPS have reduced by 69.6 per cent, 29 per cent, 31.8 per cent and 23.3 per cent, respectively for the four selected interferograms, with an average improvement of 38.4 per cent. Most importantly, after the correction, six distinct deformation areas have been identified, that is, Long Beach–Santa Ana Basin, Pomona–Ontario, San Bernardino and Elsinore basin, with the deformation velocities along the radar line-of-sight (LOS) direction ranging from −20 mm yr−1 to −30 mm yr−1 and on average around −25 mm yr−1, and Santa Fe Springs and Wilmington, with a slightly low deformation rate of about −10 mm yr−1 along LOS. Finally, through the method of stacking, we generate a mean deformation velocity map of Los Angeles over a period of 5 yr. The deformation is quite consistent with the historical deformation of the area. Thus, using the cloud-free MERIS IWV data correcting synchronized ASAR interferograms can significantly reduce the atmospheric effects in the interferograms and further better capture the ground deformation and other geophysical signals.

  11. Establishment of frame image in dynamic function renal studies

    International Nuclear Information System (INIS)

    Guedes, Germano P.; Brunetto, Sergio Q.

    1996-01-01

    Statistical procedures applied to a set of images of renal function study are described to define a region of interest (ROI) on the kidneys's contours. The kidneys geometry is considered to adapt to the emitting area in every frames

  12. Dynamic CT perfusion image data compression for efficient parallel processing.

    Science.gov (United States)

    Barros, Renan Sales; Olabarriaga, Silvia Delgado; Borst, Jordi; van Walderveen, Marianne A A; Posthuma, Jorrit S; Streekstra, Geert J; van Herk, Marcel; Majoie, Charles B L M; Marquering, Henk A

    2016-03-01

    The increasing size of medical imaging data, in particular time series such as CT perfusion (CTP), requires new and fast approaches to deliver timely results for acute care. Cloud architectures based on graphics processing units (GPUs) can provide the processing capacity required for delivering fast results. However, the size of CTP datasets makes transfers to cloud infrastructures time-consuming and therefore not suitable in acute situations. To reduce this transfer time, this work proposes a fast and lossless compression algorithm for CTP data. The algorithm exploits redundancies in the temporal dimension and keeps random read-only access to the image elements directly from the compressed data on the GPU. To the best of our knowledge, this is the first work to present a GPU-ready method for medical image compression with random access to the image elements from the compressed data.

  13. Adaptive polarization image fusion based on regional energy dynamic weighted average

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yong-qiang; PAN Quan; ZHANG Hong-cai

    2005-01-01

    According to the principle of polarization imaging and the relation between Stokes parameters and the degree of linear polarization, there are much redundant and complementary information in polarized images. Since man-made objects and natural objects can be easily distinguished in images of degree of linear polarization and images of Stokes parameters contain rich detailed information of the scene, the clutters in the images can be removed efficiently while the detailed information can be maintained by combining these images. An algorithm of adaptive polarization image fusion based on regional energy dynamic weighted average is proposed in this paper to combine these images. Through an experiment and simulations,most clutters are removed by this algorithm. The fusion method is used for different light conditions in simulation, and the influence of lighting conditions on the fusion results is analyzed.

  14. Dynamic segmentation to estimate vine vigor from ground images

    OpenAIRE

    Sáiz Rubio, Verónica; Rovira Más, Francisco

    2012-01-01

    [EN] The geographic information required to implement precision viticulture applications in real fields has led to the extensive use of remote sensing and airborne imagery. While advantageous because they cover large areas and provide diverse radiometric data, they are unreachable to most of medium-size Spanish growers who cannot afford such image sourcing. This research develops a new methodology to generate globally-referenced vigor maps in vineyards from ground images taken wit...

  15. Dynamic segmentation to estimate vine vigor from ground images

    OpenAIRE

    Sáiz-Rubio, V.; Rovira-Más, F.

    2012-01-01

    The geographic information required to implement precision viticulture applications in real fields has led to the extensive use of remote sensing and airborne imagery. While advantageous because they cover large areas and provide diverse radiometric data, they are unreachable to most of medium-size Spanish growers who cannot afford such image sourcing. This research develops a new methodology to generate globally-referenced vigor maps in vineyards from ground images taken with a camera mounte...

  16. Pulmonary dynamics and functional imaging with krypton-81m as related to generator delivery characteristics

    International Nuclear Information System (INIS)

    Kaplan, E.

    1985-01-01

    Krypton-81m supplied from a generator by continuous elution with air is used with a gamma-camera computer system to produce a sequence of images from multiple breaths, which reconstructed the time-activity images of the breathing human lung. Functional images are produced by subsequent derivation to show specific variables of the dynamic sequences. The dynamic, quantitative, and regional aspects of the respiratory cycle are thus made available in a single study. The need for the delivery of a constant ratio of /sub 81m/Kr to air is required to accurately produce these various studies

  17. High-speed videography combined with an x-ray image intensifier for dynamic radiography

    International Nuclear Information System (INIS)

    Bryant, L.E. Jr.

    1983-01-01

    The Spin Physics SP-2000 high-speed video system can be combined with an x-ray source, a dynamic event having internal (not directly visible) movement and an x-ray image intensifier to perform dynamic radiography. The cesium iodide input fluor and P-20 output fluor of the image intensifier have rapid decay to allow x-ray imaging up to 12,000 pictures per second. Applications of this technique include internal functioning of a compressor, turbulent-water action, and other mechanical actions

  18. Patient-adapted reconstruction and acquisition dynamic imaging method (PARADIGM) for MRI

    International Nuclear Information System (INIS)

    Aggarwal, Nitin; Bresler, Yoram

    2008-01-01

    Dynamic magnetic resonance imaging (MRI) is a challenging problem because the MR data acquisition is often not fast enough to meet the combined spatial and temporal Nyquist sampling rate requirements. Current approaches to this problem include hardware-based acceleration of the acquisition, and model-based image reconstruction techniques. In this paper we propose an alternative approach, called PARADIGM, which adapts both the acquisition and reconstruction to the spatio-temporal characteristics of the imaged object. The approach is based on time-sequential sampling theory, addressing the problem of acquiring a spatio-temporal signal under the constraint that only a limited amount of data can be acquired at a time instant. PARADIGM identifies a model class for the particular imaged object using a scout MR scan or auxiliary data. This object-adapted model is then used to optimize MR data acquisition, such that the imaging constraints are met, acquisition speed requirements are minimized, essentially perfect reconstruction of any object in the model class is guaranteed, and the inverse problem of reconstructing the dynamic object has a condition number of one. We describe spatio-temporal object models for various dynamic imaging applications including cardiac imaging. We present the theory underlying PARADIGM and analyze its performance theoretically and numerically. We also propose a practical MR imaging scheme for 2D dynamic cardiac imaging based on the theory. For this application, PARADIGM is predicted to provide a 10–25 × acceleration compared to the optimal non-adaptive scheme. Finally we present generalized optimality criteria and extend the scheme to dynamic imaging with three spatial dimensions

  19. Enhancement of dynamic myocardial perfusion PET images based on low-rank plus sparse decomposition.

    Science.gov (United States)

    Lu, Lijun; Ma, Xiaomian; Mohy-Ud-Din, Hassan; Ma, Jianhua; Feng, Qianjin; Rahmim, Arman; Chen, Wufan

    2018-02-01

    The absolute quantification of dynamic myocardial perfusion (MP) PET imaging is challenged by the limited spatial resolution of individual frame images due to division of the data into shorter frames. This study aims to develop a method for restoration and enhancement of dynamic PET images. We propose that the image restoration model should be based on multiple constraints rather than a single constraint, given the fact that the image characteristic is hardly described by a single constraint alone. At the same time, it may be possible, but not optimal, to regularize the image with multiple constraints simultaneously. Fortunately, MP PET images can be decomposed into a superposition of background vs. dynamic components via low-rank plus sparse (L + S) decomposition. Thus, we propose an L + S decomposition based MP PET image restoration model and express it as a convex optimization problem. An iterative soft thresholding algorithm was developed to solve the problem. Using realistic dynamic 82 Rb MP PET scan data, we optimized and compared its performance with other restoration methods. The proposed method resulted in substantial visual as well as quantitative accuracy improvements in terms of noise versus bias performance, as demonstrated in extensive 82 Rb MP PET simulations. In particular, the myocardium defect in the MP PET images had improved visual as well as contrast versus noise tradeoff. The proposed algorithm was also applied on an 8-min clinical cardiac 82 Rb MP PET study performed on the GE Discovery PET/CT, and demonstrated improved quantitative accuracy (CNR and SNR) compared to other algorithms. The proposed method is effective for restoration and enhancement of dynamic PET images. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Analysis of Land Subsidence Monitoring in Mining Area with Time-Series Insar Technology

    Science.gov (United States)

    Sun, N.; Wang, Y. J.

    2018-04-01

    Time-series InSAR technology has become a popular land subsidence monitoring method in recent years, because of its advantages such as high accuracy, wide area, low expenditure, intensive monitoring points and free from accessibility restrictions. In this paper, we applied two kinds of satellite data, ALOS PALSAR and RADARSAT-2, to get the subsidence monitoring results of the study area in two time periods by time-series InSAR technology. By analyzing the deformation range, rate and amount, the time-series analysis of land subsidence in mining area was realized. The results show that InSAR technology could be used to monitor land subsidence in large area and meet the demand of subsidence monitoring in mining area.

  1. Dynamic chest radiography: flat-panel detector (FPD) based functional X-ray imaging.

    Science.gov (United States)

    Tanaka, Rie

    2016-07-01

    Dynamic chest radiography is a flat-panel detector (FPD)-based functional X-ray imaging, which is performed as an additional examination in chest radiography. The large field of view (FOV) of FPDs permits real-time observation of the entire lungs and simultaneous right-and-left evaluation of diaphragm kinetics. Most importantly, dynamic chest radiography provides pulmonary ventilation and circulation findings as slight changes in pixel value even without the use of contrast media; the interpretation is challenging and crucial for a better understanding of pulmonary function. The basic concept was proposed in the 1980s; however, it was not realized until the 2010s because of technical limitations. Dynamic FPDs and advanced digital image processing played a key role for clinical application of dynamic chest radiography. Pulmonary ventilation and circulation can be quantified and visualized for the diagnosis of pulmonary diseases. Dynamic chest radiography can be deployed as a simple and rapid means of functional imaging in both routine and emergency medicine. Here, we focus on the evaluation of pulmonary ventilation and circulation. This review article describes the basic mechanism of imaging findings according to pulmonary/circulation physiology, followed by imaging procedures, analysis method, and diagnostic performance of dynamic chest radiography.

  2. 4D PET iterative deconvolution with spatiotemporal regularization for quantitative dynamic PET imaging.

    Science.gov (United States)

    Reilhac, Anthonin; Charil, Arnaud; Wimberley, Catriona; Angelis, Georgios; Hamze, Hasar; Callaghan, Paul; Garcia, Marie-Paule; Boisson, Frederic; Ryder, Will; Meikle, Steven R; Gregoire, Marie-Claude

    2015-09-01

    Quantitative measurements in dynamic PET imaging are usually limited by the poor counting statistics particularly in short dynamic frames and by the low spatial resolution of the detection system, resulting in partial volume effects (PVEs). In this work, we present a fast and easy to implement method for the restoration of dynamic PET images that have suffered from both PVE and noise degradation. It is based on a weighted least squares iterative deconvolution approach of the dynamic PET image with spatial and temporal regularization. Using simulated dynamic [(11)C] Raclopride PET data with controlled biological variations in the striata between scans, we showed that the restoration method provides images which exhibit less noise and better contrast between emitting structures than the original images. In addition, the method is able to recover the true time activity curve in the striata region with an error below 3% while it was underestimated by more than 20% without correction. As a result, the method improves the accuracy and reduces the variability of the kinetic parameter estimates calculated from the corrected images. More importantly it increases the accuracy (from less than 66% to more than 95%) of measured biological variations as well as their statistical detectivity. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

  3. Image dynamic range test and evaluation of Gaofen-2 dual cameras

    Science.gov (United States)

    Zhang, Zhenhua; Gan, Fuping; Wei, Dandan

    2015-12-01

    In order to fully understand the dynamic range of Gaofen-2 satellite data and support the data processing, application and next satellites development, in this article, we evaluated the dynamic range by calculating some statistics such as maximum ,minimum, average and stand deviation of four images obtained at the same time by Gaofen-2 dual cameras in Beijing area; then the maximum ,minimum, average and stand deviation of each longitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of each camera's dynamic range consistency; and these four statistics of each latitudinal overlap of PMS1,PMS2 were calculated respectively for the evaluation of the dynamic range consistency between PMS1 and PMS2 at last. The results suggest that there is a wide dynamic range of DN value in the image obtained by PMS1 and PMS2 which contains rich information of ground objects; in general, the consistency of dynamic range between the single camera images is in close agreement, but also a little difference, so do the dual cameras. The consistency of dynamic range between the single camera images is better than the dual cameras'.

  4. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies

    Energy Technology Data Exchange (ETDEWEB)

    Häggström, Ida, E-mail: haeggsti@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 and Department of Radiation Sciences, Umeå University, Umeå 90187 (Sweden); Beattie, Bradley J.; Schmidtlein, C. Ross [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York 10065 (United States)

    2016-06-15

    Purpose: To develop and evaluate a fast and simple tool called dPETSTEP (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. Methods: The tool was developed in MATLAB using both new and previously reported modules of PETSTEP (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). Results: dPETSTEP was 8000 times faster than MC. Dynamic images from dPETSTEP had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dPETSTEP and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dPETSTEP images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p < 0.01). Compared to GAUSS, dPETSTEP images and noise properties agreed better with MC. Conclusions: The authors have developed a fast and easy one-stop solution for simulations of dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dPETSTEP to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for

  5. Dynamic PET simulator via tomographic emission projection for kinetic modeling and parametric image studies

    International Nuclear Information System (INIS)

    Häggström, Ida; Beattie, Bradley J.; Schmidtlein, C. Ross

    2016-01-01

    Purpose: To develop and evaluate a fast and simple tool called dPETSTEP (Dynamic PET Simulator of Tracers via Emission Projection), for dynamic PET simulations as an alternative to Monte Carlo (MC), useful for educational purposes and evaluation of the effects of the clinical environment, postprocessing choices, etc., on dynamic and parametric images. Methods: The tool was developed in MATLAB using both new and previously reported modules of PETSTEP (PET Simulator of Tracers via Emission Projection). Time activity curves are generated for each voxel of the input parametric image, whereby effects of imaging system blurring, counting noise, scatters, randoms, and attenuation are simulated for each frame. Each frame is then reconstructed into images according to the user specified method, settings, and corrections. Reconstructed images were compared to MC data, and simple Gaussian noised time activity curves (GAUSS). Results: dPETSTEP was 8000 times faster than MC. Dynamic images from dPETSTEP had a root mean square error that was within 4% on average of that of MC images, whereas the GAUSS images were within 11%. The average bias in dPETSTEP and MC images was the same, while GAUSS differed by 3% points. Noise profiles in dPETSTEP images conformed well to MC images, confirmed visually by scatter plot histograms, and statistically by tumor region of interest histogram comparisons that showed no significant differences (p < 0.01). Compared to GAUSS, dPETSTEP images and noise properties agreed better with MC. Conclusions: The authors have developed a fast and easy one-stop solution for simulations of dynamic PET and parametric images, and demonstrated that it generates both images and subsequent parametric images with very similar noise properties to those of MC images, in a fraction of the time. They believe dPETSTEP to be very useful for generating fast, simple, and realistic results, however since it uses simple scatter and random models it may not be suitable for

  6. InSAR data analysis at Kamchatka during 2016

    Directory of Open Access Journals (Sweden)

    Larionov Igor

    2017-01-01

    Full Text Available Geophysical monitoring in seismically active areas depends on geodeformation processes in the earth's crust. Observations of earth's crust strain-stress using gps-measurements, laser interferometers give only an opportunity to analyze the dynamics in time without the possibility of extrapolation to adjacent areas. In this regard, it is useful to apply a radar interferometry technology to measure the displacements of the earth's surface. The report includes the results of processing the radar data of the Sentinel-1A satellite. Several qualitative interferometric pairs were obtained during the period from June to October 2016. A high coherence coefficient is observed in open areas in the vicinity of volcanic structures and adjacent territories, as well as on the west coast of Kamchatka, where there is no high vegetation. The main factor that significantly reduces the coherence of images is the forest cover. Possibility of estimating the surface displacement at regions with a high coherence coefficient is discussed.

  7. A rapid and robust gradient measurement technique using dynamic single-point imaging.

    Science.gov (United States)

    Jang, Hyungseok; McMillan, Alan B

    2017-09-01

    We propose a new gradient measurement technique based on dynamic single-point imaging (SPI), which allows simple, rapid, and robust measurement of k-space trajectory. To enable gradient measurement, we utilize the variable field-of-view (FOV) property of dynamic SPI, which is dependent on gradient shape. First, one-dimensional (1D) dynamic SPI data are acquired from a targeted gradient axis, and then relative FOV scaling factors between 1D images or k-spaces at varying encoding times are found. These relative scaling factors are the relative k-space position that can be used for image reconstruction. The gradient measurement technique also can be used to estimate the gradient impulse response function for reproducible gradient estimation as a linear time invariant system. The proposed measurement technique was used to improve reconstructed image quality in 3D ultrashort echo, 2D spiral, and multi-echo bipolar gradient-echo imaging. In multi-echo bipolar gradient-echo imaging, measurement of the k-space trajectory allowed the use of a ramp-sampled trajectory for improved acquisition speed (approximately 30%) and more accurate quantitative fat and water separation in a phantom. The proposed dynamic SPI-based method allows fast k-space trajectory measurement with a simple implementation and no additional hardware for improved image quality. Magn Reson Med 78:950-962, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  8. The Dynamic Photometric Stereo Method Using a Multi-Tap CMOS Image Sensor †

    Science.gov (United States)

    Yoda, Takuya; Nagahara, Hajime; Taniguchi, Rin-ichiro; Kagawa, Keiichiro; Yasutomi, Keita; Kawahito, Shoji

    2018-01-01

    The photometric stereo method enables estimation of surface normals from images that have been captured using different but known lighting directions. The classical photometric stereo method requires at least three images to determine the normals in a given scene. However, this method cannot be applied to dynamic scenes because it is assumed that the scene remains static while the required images are captured. In this work, we present a dynamic photometric stereo method for estimation of the surface normals in a dynamic scene. We use a multi-tap complementary metal-oxide-semiconductor (CMOS) image sensor to capture the input images required for the proposed photometric stereo method. This image sensor can divide the electrons from the photodiode from a single pixel into the different taps of the exposures and can thus capture multiple images under different lighting conditions with almost identical timing. We implemented a camera lighting system and created a software application to enable estimation of the normal map in real time. We also evaluated the accuracy of the estimated surface normals and demonstrated that our proposed method can estimate the surface normals of dynamic scenes. PMID:29510599

  9. The Dynamic Photometric Stereo Method Using a Multi-Tap CMOS Image Sensor.

    Science.gov (United States)

    Yoda, Takuya; Nagahara, Hajime; Taniguchi, Rin-Ichiro; Kagawa, Keiichiro; Yasutomi, Keita; Kawahito, Shoji

    2018-03-05

    The photometric stereo method enables estimation of surface normals from images that have been captured using different but known lighting directions. The classical photometric stereo method requires at least three images to determine the normals in a given scene. However, this method cannot be applied to dynamic scenes because it is assumed that the scene remains static while the required images are captured. In this work, we present a dynamic photometric stereo method for estimation of the surface normals in a dynamic scene. We use a multi-tap complementary metal-oxide-semiconductor (CMOS) image sensor to capture the input images required for the proposed photometric stereo method. This image sensor can divide the electrons from the photodiode from a single pixel into the different taps of the exposures and can thus capture multiple images under different lighting conditions with almost identical timing. We implemented a camera lighting system and created a software application to enable estimation of the normal map in real time. We also evaluated the accuracy of the estimated surface normals and demonstrated that our proposed method can estimate the surface normals of dynamic scenes.

  10. Bioluminescent system for dynamic imaging of cell and animal behavior

    Energy Technology Data Exchange (ETDEWEB)

    Hara-Miyauchi, Chikako [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Saitama 351-0198 (Japan); Department of Biophysics and Biochemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo 113-8510 (Japan); Tsuji, Osahiko [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Hanyu, Aki [Division of Biochemistry, The Cancer Institute of the Japanese Foundation for Cancer Research, Tokyo 135-8550 (Japan); Okada, Seiji [Department of Advanced Medical Initiatives, Faculty of Medical Sciences, Kyushu University, Fukuoka 812-8582 (Japan); Yasuda, Akimasa [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Fukano, Takashi [Laboratory for Cell Function Dynamics, Brain Science Institute, RIKEN, Saitama 351-0198 (Japan); Akazawa, Chihiro [Department of Biophysics and Biochemistry, Graduate School of Health Care Sciences, Tokyo Medical and Dental University, Tokyo 113-8510 (Japan); Nakamura, Masaya [Department of Orthopedic Surgery, Keio University School of Medicine, Tokyo 160-8582 (Japan); Imamura, Takeshi [Department of Molecular Medicine for Pathogenesis, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295 (Japan); Core Research for Evolutional Science and Technology, The Japan Science and Technology Corporation, Tokyo 135-8550 (Japan); Matsuzaki, Yumi [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Okano, Hirotaka James, E-mail: hjokano@jikei.ac.jp [Department of Physiology, Keio University School of Medicine, Tokyo 160-8582 (Japan); Division of Regenerative Medicine Jikei University School of Medicine, Tokyo 150-8461 (Japan); and others

    2012-03-09

    Highlights: Black-Right-Pointing-Pointer We combined a yellow variant of GFP and firefly luciferase to make ffLuc-cp156. Black-Right-Pointing-Pointer ffLuc-cp156 showed improved photon yield in cultured cells and transgenic mice. Black-Right-Pointing-Pointer ffLuc-cp156 enabled video-rate bioluminescence imaging of freely-moving animals. Black-Right-Pointing-Pointer ffLuc-cp156 mice enabled tracking real-time drug delivery in conscious animals. -- Abstract: The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.

  11. Bioluminescent system for dynamic imaging of cell and animal behavior

    International Nuclear Information System (INIS)

    Hara-Miyauchi, Chikako; Tsuji, Osahiko; Hanyu, Aki; Okada, Seiji; Yasuda, Akimasa; Fukano, Takashi; Akazawa, Chihiro; Nakamura, Masaya; Imamura, Takeshi; Matsuzaki, Yumi; Okano, Hirotaka James

    2012-01-01

    Highlights: ► We combined a yellow variant of GFP and firefly luciferase to make ffLuc-cp156. ► ffLuc-cp156 showed improved photon yield in cultured cells and transgenic mice. ► ffLuc-cp156 enabled video-rate bioluminescence imaging of freely-moving animals. ► ffLuc-cp156 mice enabled tracking real-time drug delivery in conscious animals. -- Abstract: The current utility of bioluminescence imaging is constrained by a low photon yield that limits temporal sensitivity. Here, we describe an imaging method that uses a chemiluminescent/fluorescent protein, ffLuc-cp156, which consists of a yellow variant of Aequorea GFP and firefly luciferase. We report an improvement in photon yield by over three orders of magnitude over current bioluminescent systems. We imaged cellular movement at high resolution including neuronal growth cones and microglial cell protrusions. Transgenic ffLuc-cp156 mice enabled video-rate bioluminescence imaging of freely moving animals, which may provide a reliable assay for drug distribution in behaving animals for pre-clinical studies.

  12. Image processing analysis of vortex dynamics of lobed jets from three-dimensional diffusers

    International Nuclear Information System (INIS)

    Nastase, Ilinca; Meslem, Amina; El Hassan, Mouhammad

    2011-01-01

    The passive control of jet flows with the aim to enhance mixing and entrainment is of wide practical interest. Our purpose here is to develop new air diffusers for heating ventilating air conditioning systems by using lobed geometry nozzles, in order to ameliorate the users' thermal comfort. Two turbulent six-lobed air jets, issued from a lobed tubular nozzle and an innovative hemispherical lobed nozzle, were studied experimentally. It was shown that the proposed innovative concept of a lobed jet, which can be easily integrated in air diffusion devices, is very efficient regarding induction capability. A vortical dynamics analysis for the two jets is performed using a new method of image processing, namely dynamic mode decomposition. A validation of this method is also proposed suggesting that the dynamical mode decomposition (DMD) image processing method succeeds in capturing the most dominant frequencies of the flow dynamics, which in our case are related to the quite special dynamics of the Kelvin–Helmholtz vortices.

  13. The efficacy of fat suppressed and gadolinium enhanced dynamic MR imaging in pancreatic adenocarcinomas

    International Nuclear Information System (INIS)

    Gabata, Toshifumi

    1994-01-01

    The efficacy of both fat suppressed T1-weighted imaging (T1WI) and dynamic gadolinium-enhanced MR imaging (dynamic MRI) was compared with conventional MR sequences and dynamic CT in 22 patients with histologically proven pancreatic adenocarcinoma (PAC). In the control group of 30 patients without pancreatic disease, the pancreas was shown as a markedly higher signal intensity on fat suppressed T1WI than on conventional MR sequences. The signal noise ratio (SNR) of the normal pancreas and the contrast noise ratio (CNR) between the normal pancreas and muscle were significantly higher on fat suppressed T1WI than the other MR sequences. In the group of PAC patients without chronic pancreatitis (n=14), CNR between the tumor and the normal pancreas significantly differed among imaging techniques, including fat suppressed T1WI, dynamic MRI, and the other conventional MR sequences. In the group of PAC with chronic pancreatitis (n=8), CNR between the tumor and the associated chronic pancreatitis was remarkably diminished on both fat suppressed T1WI and conventional T1WI; however, it was significantly higher on dynamic MRI than the other pulse sequences. The early phase of dynamic MRI clearly identified the tumors in the group of PAC. The capability of conventional T1WI and dynamic CT to demonstrate peripancreatic tumor extension was significantly higher than that of fat suppressed T1WI. In conclusion, fat suppressed T1WI and dynamic MRI were useful in detecting pancreatic carcinoma. (N.K.)

  14. On the use of InSAR technology to assess land subsidence in Jakarta coastal flood plain

    Science.gov (United States)

    Koudogbo, Fifame; Duro, Javier; Garcia Robles, Javier; Arnaud, Alain; Abidin, Hasanuddin Z.

    2014-05-01

    Jakarta is the capital of Indonesia and is home to approximately 10 million people on the coast of the Java Sea. It is situated on the northern coastal alluvial plane of Java which shares boundaries with West Java Province in the south and in the east, and with Banten Province in the west. The Capital District of Jakarta (DKI) sits in the lowest lying areas of the basin. Its topography varies, with the northern part just meters above current sea level and lying on a flood plain. Subsequently, this portion of the city frequently floods. The southern part of the city is hilly. Thirteen major rivers flow through Jakarta to the Java Sea. The Ciliwung River is the most significant river and divides the city West to East. In the last three decades, urban growing of Jakarta has been very fast in sectors as industry, trade, transportation, real estate, among others. This exponential development has caused several environmental issues; land subsidence is one of them. Subsidence in Jakarta has been known since the early part of the 20th century. It is mainly due to groundwater extraction, the fast development (construction load), soil natural consolidation and tectonics. Evidence of land subsidence exists through monitoring with GPS, level surveys and InSAR investigations. InSAR states for "Interferometric Synthetic Aperture Radar". Its principle is based on comparing the distance between the satellite and the ground in consecutive satellite passes over the same area on the Earth's surface. Radar satellites images record, with very high precision, the distance travelled by the radar signal that is emitted by the satellite is registered. When this distance is compared through time, InSAR technology can provide highly accurate ground deformation measurements. ALTAMIRA INFORMATION, company specialized in ground motion monitoring, has developed GlobalSARTM, which combines several processing techniques and algorithms based on InSAR technology, to achieve ground motion

  15. Satellite image based quantification of invasion and patch dynamics ...

    Indian Academy of Sciences (India)

    dynamics of mesquite (Prosopis juliflora) in Great Rann ... The present study was conducted in the Great Rann of Kachchh, part of Kachchh ... The process of Prosopis invasion shows high patch initiation, followed by .... formed by determining the percentage relationship .... poor women in northwestern India benefit from the.

  16. Rapid dynamic MR imaging of the heart in the evaluation of valvular function

    International Nuclear Information System (INIS)

    Utz, J.A.; Herfkens, R.J.; Heinsimer, J.; Glover, G.H.; Pelc, N.J.; Shimakawa, A.

    1986-01-01

    Dynamic MR images were obtained utilizing a repetition time of 21 msec, a 30-degree flip angle, and 12-msec gradient refocused echoes. Images were ECG-triggered and constructed at 16 images per cardiac cycle. To assess the sensitivity of dynamic MR imaging of valvular regurgitation, 17 patients were so examined and results were compared with results of echocardiography or cardiac catheterization. Mitral and tricuspid valves were well visualized in all patients. Regurgitation was demonstrated in 14 cases as an area of decreased signal extending from the valve into the regurgitant chamber, corresponding in time to ventricular systole for mitral and tricuspid regurgitation and diastole for aortic insufficiency. There were no false-negative MR imaging studies

  17. A High-Dynamic-Range Optical Remote Sensing Imaging Method for Digital TDI CMOS

    Directory of Open Access Journals (Sweden)

    Taiji Lan

    2017-10-01

    Full Text Available The digital time delay integration (digital TDI technology of the complementary metal-oxide-semiconductor (CMOS image sensor has been widely adopted and developed in the optical remote sensing field. However, the details of targets that have low illumination or low contrast in scenarios of high contrast are often drowned out because of the superposition of multi-stage images in digital domain multiplies the read noise and the dark noise, thus limiting the imaging dynamic range. Through an in-depth analysis of the information transfer model of digital TDI, this paper attempts to explore effective ways to overcome this issue. Based on the evaluation and analysis of multi-stage images, the entropy-maximized adaptive histogram equalization (EMAHE algorithm is proposed to improve the ability of images to express the details of dark or low-contrast targets. Furthermore, in this paper, an image fusion method is utilized based on gradient pyramid decomposition and entropy weighting of different TDI stage images, which can improve the detection ability of the digital TDI CMOS for complex scenes with high contrast, and obtain images that are suitable for recognition by the human eye. The experimental results show that the proposed methods can effectively improve the high-dynamic-range imaging (HDRI capability of the digital TDI CMOS. The obtained images have greater entropy and average gradients.

  18. Non-destructive Faraday imaging of dynamically controlled ultracold atoms

    DEFF Research Database (Denmark)

    Gajdacz, Miroslav; Pedersen, Poul Lindholm; Mørch, Troels

    2013-01-01

    We describe an easily implementable method for non-destructive measurements of ultracold atomic clouds based on dark field imaging of spatially resolved Faraday rotation. The signal-to-noise ratio is analyzed theoretically and, in the absence of experimental imperfections, the sensitivity limit...

  19. Dynamic whole-body PET parametric imaging: II. Task-oriented statistical estimation.

    Science.gov (United States)

    Karakatsanis, Nicolas A; Lodge, Martin A; Zhou, Y; Wahl, Richard L; Rahmim, Arman

    2013-10-21

    In the context of oncology, dynamic PET imaging coupled with standard graphical linear analysis has been previously employed to enable quantitative estimation of tracer kinetic parameters of physiological interest at the voxel level, thus, enabling quantitative PET parametric imaging. However, dynamic PET acquisition protocols have been confined to the limited axial field-of-view (~15-20 cm) of a single-bed position and have not been translated to the whole-body clinical imaging domain. On the contrary, standardized uptake value (SUV) PET imaging, considered as the routine approach in clinical oncology, commonly involves multi-bed acquisitions, but is performed statically, thus not allowing for dynamic tracking of the tracer distribution. Here, we pursue a transition to dynamic whole-body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed dynamic PET acquisition protocols and parametric imaging methods. In a companion study, we presented a novel clinically feasible dynamic (4D) multi-bed PET acquisition protocol as well as the concept of whole-body PET parametric imaging employing Patlak ordinary least squares (OLS) regression to estimate the quantitative parameters of tracer uptake rate Ki and total blood distribution volume V. In the present study, we propose an advanced hybrid linear regression framework, driven by Patlak kinetic voxel correlations, to achieve superior trade-off between contrast-to-noise ratio (CNR) and mean squared error (MSE) than provided by OLS for the final Ki parametric images, enabling task-based performance optimization. Overall, whether the observer's task is to detect a tumor or quantitatively assess treatment response, the proposed statistical estimation framework can be adapted to satisfy the specific task performance criteria, by adjusting the Patlak correlation-coefficient (WR) reference value. The multi-bed dynamic acquisition protocol, as optimized in the preceding companion study

  20. Dynamic whole-body PET parametric imaging: II. Task-oriented statistical estimation

    International Nuclear Information System (INIS)

    Karakatsanis, Nicolas A; Lodge, Martin A; Zhou, Y; Wahl, Richard L; Rahmim, Arman

    2013-01-01

    In the context of oncology, dynamic PET imaging coupled with standard graphical linear analysis has been previously employed to enable quantitative estimation of tracer kinetic parameters of physiological interest at the voxel level, thus, enabling quantitative PET parametric imaging. However, dynamic PET acquisition protocols have been confined to the limited axial field-of-view (∼15–20 cm) of a single-bed position and have not been translated to the whole-body clinical imaging domain. On the contrary, standardized uptake value (SUV) PET imaging, considered as the routine approach in clinical oncology, commonly involves multi-bed acquisitions, but is performed statically, thus not allowing for dynamic tracking of the tracer distribution. Here, we pursue a transition to dynamic whole-body PET parametric imaging, by presenting, within a unified framework, clinically feasible multi-bed dynamic PET acquisition protocols and parametric imaging methods. In a companion study, we presented a novel clinically feasible dynamic (4D) multi-bed PET acquisition protocol as well as the concept of whole-body PET parametric imaging employing Patlak ordinary least squares (OLS) regression to estimate the quantitative parameters of tracer uptake rate K i and total blood distribution volume V. In the present study, we propose an advanced hybrid linear regression framework, driven by Patlak kinetic voxel correlations, to achieve superior trade-off between contrast-to-noise ratio (CNR) and mean squared error (MSE) than provided by OLS for the final K i parametric images, enabling task-based performance optimization. Overall, whether the observer's task is to detect a tumor or quantitatively assess treatment response, the proposed statistical estimation framework can be adapted to satisfy the specific task performance criteria, by adjusting the Patlak correlation-coefficient (WR) reference value. The multi-bed dynamic acquisition protocol, as optimized in the preceding companion

  1. Diagnostic value of dynamic perfusion MR imaging in benign and malignant musculoskeletal lesions

    International Nuclear Information System (INIS)

    Choi, Byeong Kyoo; Lee, Sang Hoon; Cha, Ji Hyeon; Kim, Sung Moon; Shin, Myung Jin; Han, Heon; Kim, Sam Soo; Lee, Ji Yeon; Jeon, Yong Hwan

    2008-01-01

    To assess the diagnostic value of dynamic perfusion MR imaging for differentiation between benign and malignant musculoskeletal lesions. Dynamic perfusion MR imaging was performed using a 3.0 T system in 32 female and 30 male patients (aged 10-90 years, mean age, 43 years). Following the assessment of the precontrast imaging, a dynamic study was performed. This dynamic technique allowed for 638 images to be obtained at 11 levels throughout the lesion. Twenty-eight lesions originated within bone (8 benign, 20 malignant), whereas 34 lesions were of soft tissue origin (22 benign, 12 malignant). The final diagnosis was histopathologically confirmed in all patients. To differentiate between benign and malignant lesions, we analyzed the four parameters: (maximal relative enhancement (MRE), time to peak (TTP), wash in rate (WI), steepest slope (SS) and the distribution of time intensity curve (TIC) patterns. The TTP, WI, and SS values of malignant lesions were statistically significant from those of benign lesions(ρ < 0.05). However, the difference for the MRE values was not statistically significant. The distribution of TIC patterns was a helpful indicator of benign or malignant state, however the difference between the two states was not significant. Dynamic perfusion MR imaging is a helpful tool in differentiating benign and malignant musculoskeletal lesions

  2. Electric Potential and Electric Field Imaging with Dynamic Applications & Extensions

    Science.gov (United States)

    Generazio, Ed

    2017-01-01

    The technology and methods for remote quantitative imaging of electrostatic potentials and electrostatic fields in and around objects and in free space is presented. Electric field imaging (EFI) technology may be applied to characterize intrinsic or existing electric potentials and electric fields, or an externally generated electrostatic field made be used for volumes to be inspected with EFI. The baseline sensor technology (e-Sensor) and its construction, optional electric field generation (quasi-static generator), and current e- Sensor enhancements (ephemeral e-Sensor) are discussed. Critical design elements of current linear and real-time two-dimensional (2D) measurement systems are highlighted, and the development of a three dimensional (3D) EFI system is presented. Demonstrations for structural, electronic, human, and memory applications are shown. Recent work demonstrates that phonons may be used to create and annihilate electric dipoles within structures. Phonon induced dipoles are ephemeral and their polarization, strength, and location may be quantitatively characterized by EFI providing a new subsurface Phonon-EFI imaging technology. Results from real-time imaging of combustion and ion flow, and their measurement complications, will be discussed. Extensions to environment, Space and subterranean applications will be presented, and initial results for quantitative characterizing material properties are shown. A wearable EFI system has been developed by using fundamental EFI concepts. These new EFI capabilities are demonstrated to characterize electric charge distribution creating a new field of study embracing areas of interest including electrostatic discharge (ESD) mitigation, manufacturing quality control, crime scene forensics, design and materials selection for advanced sensors, combustion science, on-orbit space potential, container inspection, remote characterization of electronic circuits and level of activation, dielectric morphology of

  3. A robust state-space kinetics-guided framework for dynamic PET image reconstruction

    International Nuclear Information System (INIS)

    Tong, S; Alessio, A M; Kinahan, P E; Liu, H; Shi, P

    2011-01-01

    Dynamic PET image reconstruction is a challenging issue due to the low SNR and the large quantity of spatio-temporal data. We propose a robust state-space image reconstruction (SSIR) framework for activity reconstruction in dynamic PET. Unlike statistically-based frame-by-frame methods, tracer kinetic modeling is incorporated to provide physiological guidance for the reconstruction, harnessing the temporal information of the dynamic data. Dynamic reconstruction is formulated in a state-space representation, where a compartmental model describes the kinetic processes in a continuous-time system equation, and the imaging data are expressed in a discrete measurement equation. Tracer activity concentrations are treated as the state variables, and are estimated from the dynamic data. Sampled-data H ∞ filtering is adopted for robust estimation. H ∞ filtering makes no assumptions on the system and measurement statistics, and guarantees bounded estimation error for finite-energy disturbances, leading to robust performance for dynamic data with low SNR and/or errors. This alternative reconstruction approach could help us to deal with unpredictable situations in imaging (e.g. data corruption from failed detector blocks) or inaccurate noise models. Experiments on synthetic phantom and patient PET data are performed to demonstrate feasibility of the SSIR framework, and to explore its potential advantages over frame-by-frame statistical reconstruction approaches.

  4. Registration of dynamic dopamine D2receptor images using principal component analysis

    International Nuclear Information System (INIS)

    Acton, P.D.; Ell, P.J.; Pilowsky, L.S.; Brammer, M.J.; Suckling, J.

    1997-01-01

    This paper describes a novel technique for registering a dynamic sequence of single-photon emission tomography (SPET) dopamine D 2 receptor images, using principal component analysis (PCA). Conventional methods for registering images, such as count difference and correlation coefficient algorithms, fail to take into account the dynamic nature of the data, resulting in large systematic errors when registering time-varying images. However, by using principal component analysis to extract the temporal structure of the image sequence, misregistration can be quantified by examining the distribution of eigenvalues. The registration procedures were tested using a computer-generated dynamic phantom derived from a high-resolution magnetic resonance image of a realistic brain phantom. Each method was also applied to clinical SPET images of dopamine D 2 receptors, using the ligands iodine-123 iodobenzamide and iodine-123 epidepride, to investigate the influence of misregistration on kinetic modelling parameters and the binding potential. The PCA technique gave highly significant (P 123 I-epidepride scans. The PCA method produced data of much greater quality for subsequent kinetic modelling, with an improvement of nearly 50% in the χ 2 of the fit to the compartmental model, and provided superior quality registration of particularly difficult dynamic sequences. (orig.)

  5. Static, dynamic and first-pass MR imaging of musculoskeletal lesions using gadodiamide injection

    International Nuclear Information System (INIS)

    Verstraete, K.L.; Vanzieleghem, B.; Deene, Y. de; Palmans, H.; Greef, D. de; Kristoffersen, D.T.; Uyttendaele, D.; Roels, J.; Hamers, J.; Kunnen, M.

    1995-01-01

    Forty-five patients with known or suspected musculoskeletal tumors were examined with static and dynamic MR imaging to evaluate the safety, tolerability and diagnostic utility of gadodiamide injection and to assess the diagnostic value of dynamic MR imaging and parametric 'first-pass' (FP) images. The proportion of patients presenting more diagnostic information on the contrast-enhanced compared to the precontrast spin-echo examinations was determined. The dynamic enhancement characteristics were evaluated with time-intensity curves and parametric images of the FP enhancement rate. The tolerance of gadodiamide injection was good. Contrast enhancement was useful for delineating tumour from muscle, and differentiating viable from necrotic tissue and cystic from solid lesions. Malignant tumors showed a significantly higher slope value, earlier onset of enhancement, and higher maximum enhancement than benign lesions. However, slope values could not be used to predict the malignant potential of a lesion, due to overlap between highly vascular benign and low vascular malignant lesions. By displaying highly vascular areas, parametric FP images provided useful information on the most active part in a tumour before biopsy and for assessing the incorporation of bone-chip allografts. Static, dynamic and FP MR imaging using gadodiamide injection appears safe and provides useful information for diagnosis, biospy and follow-up of musculoskeletal lesions. (orig.)

  6. 4D rotational x-ray imaging of wrist joint dynamic motion

    International Nuclear Information System (INIS)

    Carelsen, Bart; Bakker, Niels H.; Strackee, Simon D.; Boon, Sjirk N.; Maas, Mario; Sabczynski, Joerg; Grimbergen, Cornelis A.; Streekstra, Geert J.

    2005-01-01

    Current methods for imaging joint motion are limited to either two-dimensional (2D) video fluoroscopy, or to animated motions from a series of static three-dimensional (3D) images. 3D movement patterns can be detected from biplane fluoroscopy images matched with computed tomography images. This involves several x-ray modalities and sophisticated 2D to 3D matching for the complex wrist joint. We present a method for the acquisition of dynamic 3D images of a moving joint. In our method a 3D-rotational x-ray (3D-RX) system is used to image a cyclically moving joint. The cyclic motion is synchronized to the x-ray acquisition to yield multiple sets of projection images, which are reconstructed to a series of time resolved 3D images, i.e., four-dimensional rotational x ray (4D-RX). To investigate the obtained image quality parameters the full width at half maximum (FWHM) of the point spread function (PSF) via the edge spread function and the contrast to noise ratio between air and phantom were determined on reconstructions of a bullet and rod phantom, using 4D-RX as well as stationary 3D-RX images. The CNR in volume reconstructions based on 251 projection images in the static situation and on 41 and 34 projection images of a moving phantom were 6.9, 3.0, and 2.9, respectively. The average FWHM of the PSF of these same images was, respectively, 1.1, 1.7, and 2.2 mm orthogonal to the motion and parallel to direction of motion 0.6, 0.7, and 1.0 mm. The main deterioration of 4D-RX images compared to 3D-RX images is due to the low number of projection images used and not to the motion of the object. Using 41 projection images seems the best setting for the current system. Experiments on a postmortem wrist show the feasibility of the method for imaging 3D dynamic joint motion. We expect that 4D-RX will pave the way to improved assessment of joint disorders by detection of 3D dynamic motion patterns in joints

  7. On the Design of Radar Corner Reflectors for Deformation Monitoring in Multi-Frequency InSAR

    Directory of Open Access Journals (Sweden)

    Matthew C. Garthwaite

    2017-06-01

    Full Text Available Trihedral corner reflectors are being increasingly used as point targets in deformation monitoring studies using interferometric synthetic aperture radar (InSAR techniques. The frequency and size dependence of the corner reflector Radar Cross Section (RCS means that no single design can perform equally in all the possible imaging modes and radar frequencies available on the currently orbiting Synthetic Aperture Radar (SAR satellites. Therefore, either a corner reflector design tailored to a specific data type or a compromise design for multiple data types is required. In this paper, I outline the practical and theoretical considerations that need to be made when designing appropriate radar targets, with a focus on supporting multi-frequency SAR data. These considerations are tested by performing field experiments on targets of different size using SAR images from TerraSAR-X, COSMO-SkyMed and RADARSAT-2. Phase noise behaviour in SAR images can be estimated by measuring the Signal-to-Clutter ratio (SCR in individual SAR images. The measured SCR of a point target is dependent on its RCS performance and the influence of clutter near to the deployed target. The SCR is used as a metric to estimate the expected InSAR displacement error incurred by the design of each target and to validate these observations against theoretical expectations. I find that triangular trihedral corner reflectors as small as 1 m in dimension can achieve a displacement error magnitude of a tenth of a millimetre or less in medium-resolution X-band data. Much larger corner reflectors (2.5 m or greater are required to achieve the same displacement error magnitude in medium-resolution C-band data. Compromise designs should aim to satisfy the requirements of the lowest SAR frequency to be used, providing that these targets will not saturate the sensor of the highest frequency to be used. Finally, accurate boresight alignment of the corner reflector can be critical to the overall

  8. Dynamic PET and Optical Imaging and Compartment Modeling using a Dual-labeled Cyclic RGD Peptide Probe.

    Science.gov (United States)

    Zhu, Lei; Guo, Ning; Li, Quanzheng; Ma, Ying; Jacboson, Orit; Lee, Seulki; Choi, Hak Soo; Mansfield, James R; Niu, Gang; Chen, Xiaoyuan

    2012-01-01

    The aim of this study is to determine if dynamic optical imaging could provide comparable kinetic parameters to that of dynamic PET imaging by a near-infrared dye/(64)Cu dual-labeled cyclic RGD peptide. The integrin α(v)β(3) binding RGD peptide was conjugated with a macrocyclic chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) for copper labeling and PET imaging and a near-infrared dye ZW-1 for optical imaging. The in vitro biological activity of RGD-C(DOTA)-ZW-1 was characterized by cell staining and receptor binding assay. Sixty-min dynamic PET and optical imaging were acquired on a MDA-MB-435 tumor model. Singular value decomposition (SVD) method was applied to compute the dynamic optical signal from the two-dimensional optical projection images. Compartment models were used to quantitatively analyze and compare the dynamic optical and PET data. The dual-labeled probe (64)Cu-RGD-C(DOTA)-ZW-1 showed integrin specific binding in vitro and in vivo. The binding potential (Bp) derived from dynamic optical imaging (1.762 ± 0.020) is comparable to that from dynamic PET (1.752 ± 0.026). The signal un-mixing process using SVD improved the accuracy of kinetic modeling of 2D dynamic optical data. Our results demonstrate that 2D dynamic optical imaging with SVD analysis could achieve comparable quantitative results as dynamic PET imaging in preclinical xenograft models.

  9. InSAR Deformation Time Series Processed On-Demand in the Cloud

    Science.gov (United States)

    Horn, W. B.; Weeden, R.; Dimarchi, H.; Arko, S. A.; Hogenson, K.

    2017-12-01

    During this past year, ASF has developed a cloud-based on-demand processing system known as HyP3 (http://hyp3.asf.alaska.edu/), the Hybrid Pluggable Processing Pipeline, for Synthetic Aperture Radar (SAR) data. The system makes it easy for a user who doesn't have the time or inclination to install and use complex SAR processing software to leverage SAR data in their research or operations. One such processing algorithm is generation of a deformation time series product, which is a series of images representing ground displacements over time, which can be computed using a time series of interferometric SAR (InSAR) products. The set of software tools necessary to generate this useful product are difficult to install, configure, and use. Moreover, for a long time series with many images, the processing of just the interferograms can take days. Principally built by three undergraduate students at the ASF DAAC, the deformation time series processing relies the new Amazon Batch service, which enables processing of jobs with complex interconnected dependencies in a straightforward and efficient manner. In the case of generating a deformation time series product from a stack of single-look complex SAR images, the system uses Batch to serialize the up-front processing, interferogram generation, optional tropospheric correction, and deformation time series generation. The most time consuming portion is the interferogram generation, because even for a fairly small stack of images many interferograms need to be processed. By using AWS Batch, the interferograms are all generated in parallel; the entire process completes in hours rather than days. Additionally, the individual interferograms are saved in Amazon's cloud storage, so that when new data is acquired in the stack, an updated time series product can be generated with minimal addiitonal processing. This presentation will focus on the development techniques and enabling technologies that were used in developing the time

  10. Photoelectron imaging, probe of the dynamics: from atoms... to clusters

    International Nuclear Information System (INIS)

    Lepine, F.

    2003-06-01

    This thesis concerns the study of the deexcitation of clusters and atoms by photoelectron imaging. The first part is dedicated to thermionic emission of a finite size system. A 3-dimensional imaging setup allows us to measure the time evolution of the kinetic energy spectrum of electrons emitted from different clusters (W n - , C n - , C 60 ). Then we have a direct access to the fundamental quantities which characterize this statistical emission: the temperature of the finite heat bath and the decay rate. The second part concerns the ionization of atomic Rydberg states placed in a static electric field. We performed the first experiment of photoionization microscopy which allows us to obtain a picture which is the macroscopic projection of the electronic wave function. Then we have access to the detail of the photoionization and particularly to the quantum properties of the electron usually confined at the atomic scale. (author)

  11. Real-time dynamic imaging of virus distribution in vivo.

    Directory of Open Access Journals (Sweden)

    Sean E Hofherr

    2011-02-01

    Full Text Available The distribution of viruses and gene therapy vectors is difficult to assess in a living organism. For instance, trafficking in murine models can usually only be assessed after sacrificing the animal for tissue sectioning or extraction. These assays are laborious requiring whole animal sectioning to ascertain tissue localization. They also obviate the ability to perform longitudinal or kinetic studies in one animal. To track viruses after systemic infection, we have labeled adenoviruses with a near-infrared (NIR fluorophore and imaged these after intravenous injection in mice. Imaging was able to track and quantitate virus particles entering the jugular vein simultaneous with injection, appearing in the heart within 500 milliseconds, distributing in the bloodstream and throughout the animal within 7 seconds, and that the bulk of virus distribution was essentially complete within 3 minutes. These data provide the first in vivo real-time tracking of the rapid initial events of systemic virus infection.

  12. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  13. Dynamic image characteristics of pulmonary tuberculosis with diabetes mellitus

    International Nuclear Information System (INIS)

    Zhou Xinhua

    2000-01-01

    Objective: To analyze image characteristics of pulmonary tuberculosis associated with diabetes mellitus and observe the changes of pulmonary tuberculotic lesions influenced by the state of hyperglycosemia. Methods: Examinations of chest plain film and tomography were taken in 68 patients with pulmonary tuberculosis and diabetes, and additional CT scans were done in 38 patients among them. Radiological examinations of lung and blood sugar test were taken at the interval of 2, 3, and 4-6 months in all 68 patients under the treatment of regular blood sugar control and antituberculosis, which compared with 30 patients with pulmonary tuberculosis only. Results: The images of X-ray and CT showed major lesions of massive patchy shadow in 55 patients (80.9%), or multiple small patchy shadow in 13(19.1%) and cavity 61(89.7%). After 2 month's treatment, enlargement of patchy shadow and cavity were found in 9(23.7%)and 10(28.6%)cases, respectively with overall deterioration rates of 65.8% in group of 38 patients with level of blood sugar over 7.0 mmol/L, which was significantly higher than that of the control group 7.0 mmol/L(x 2 =16.4, P 2 = 0.81, P>0.5) with the well controlled blood sugar after treatment of 3 months or more. The follow-up images showed similar results between the groups of pulmonary tuberculosis only and the group of pulmonary tuberculosis with high level of blood sugar, in which the overall deterioration rates was significant less than the group of pulmonary tuberculosis with level of blood sugar more than 8.0 mmol/L(x 2 =5.46, P<0.025). Conclusion: There are imaging characteristics in patient with pulmonary tuberculosis and diabetes mellitus. The state of hyperglycosemia is a vital factor, which influences the radiological changes of pulmonary tuberculosis

  14. Use of dynamic images in radiology education: Movies of CT and MRI in the anatomy classroom.

    Science.gov (United States)

    Jang, Hye Won; Oh, Chang-Seok; Choe, Yeon Hyeon; Jang, Dong Su

    2018-04-19

    Radiology education is a key component in many preclinical anatomy courses. However, the reported effectiveness of radiology education within such anatomy classrooms has varied. This study was conducted to determine if a novel educational method using dynamic images of movies of computed tomography (CT) and magnetic resonance imaging (MRI) was effective in radiology education during a preclinical anatomy course, aided by clay modeling, specific hand gestures (digit anatomy), and reports from dissection findings uploaded to the anatomy course website (digital reports). Feedback surveys using a five-point Likert scale were administered to better clarify students' opinions regarding their understanding of CT and MRI of anatomical structures, as well as to determine if such preclinical radiology education was helpful in their clinical studies. After completion of the anatomy course taught with dynamic images of CT and MRI, most students demonstrated an adequate understanding of basic CT and MR images. Additionally, students in later clinical years generally believed that their study of radiologic images during the preclinical anatomy course was helpful for their clinical studies and clerkship rotations. Moreover, student scores on imaging anatomy examinations demonstrated meaningful improvements in performance after using dynamic images from movies of CT and MRI. Anat Sci Educ. © 2018 American Association of Anatomists. © 2018 American Association of Anatomists.

  15. Temporal contrast enhancement and parametric imaging for the visualisation of time patterns in dynamic scintigraphic imaging

    International Nuclear Information System (INIS)

    Deconinck, F.; Bossuyt, A.; Lepoudre, R.

    1982-01-01

    Image contrast, photon noise and sampling frequency limit the visual extraction of relevant temporal information in scintigraphic image series. When the Unitation is mainly due to low temporal contrast, temporal contrast enhancement will strongly improve the perceptibility of time patterns in the series. When the limitation is due to photon noise and limited temporal sampling, parametric imaging by means of the Hadamard transform can visualise temporal patterns. (WU)

  16. In-Vivo High Dynamic Range Vector Flow Imaging

    DEFF Research Database (Denmark)

    Villagómez Hoyos, Carlos Armando; Stuart, Matthias Bo; Jensen, Jørgen Arendt

    2015-01-01

    example with a high dynamic velocity range. Velocities with an order of magnitude apart are detected on the femoral artery of a 41 years old healthy individual. Three distinct heart cycles are captured during a 3 secs acquisition. The estimated vector velocities are compared against each other within...... the heart cycle. The relative standard deviation of the measured velocity magnitude between the three peak systoles was found to be 5.11% with a standard deviation on the detected angle of 1.06◦ . In the diastole, it was 1.46% and 6.18◦ , respectively. Results proves that the method is able to estimate flow...

  17. Dynamical image-charge effect in molecular tunnel junctions

    DEFF Research Database (Denmark)

    Jin, Chengjun; Thygesen, Kristian Sommer

    2014-01-01

    the finite IC formation time affects charge transport through a molecule suspended between two electrodes. For a single-level model, an analytical treatment shows that the conductance is suppressed by a factor Z(2), where Z is the quasiparticle renormalization factor, compared to the static IC approximation...... that the dynamical corrections can reduce the conductance by more than a factor of two when compared to static GW or density functional theory where the molecular energy levels have been shifted to match the exact quasiparticle levels....

  18. Dynamic imaging in mild traumatic brain injury: support for the theory of medial temporal vulnerability.

    Science.gov (United States)

    Umile, Eric M; Sandel, M Elizabeth; Alavi, Abass; Terry, Charles M; Plotkin, Rosette C

    2002-11-01

    To determine whether patients with mild traumatic brain injury (TBI) and persistent postconcussive symptoms have evidence of temporal lobe injury on dynamic imaging. Case series. An academic medical center. Twenty patients with a clinical diagnosis of mild TBI and persistent postconcussive symptoms were referred for neuropsychologic evaluation and dynamic imaging. Fifteen (75%) had normal magnetic resonance imaging (MRI) and/or computed tomography (CT) scans at the time of injury. Neuropsychologic testing, positron-emission tomography (PET), and single-photon emission-computed tomography (SPECT). Temporal lobe findings on static imaging (MRI, CT) and dynamic imaging (PET, SPECT); neuropsychologic test findings on measures of verbal and visual memory. Testing documented neurobehavioral deficits in 19 patients (95%). Dynamic imaging documented abnormal findings in 18 patients (90%). Fifteen patients (75%) had temporal lobe abnormalities on PET and SPECT (primarily in medial temporal regions); abnormal findings were bilateral in 10 patients (50%) and unilateral in 5 (25%). Six patients (30%) had frontal abnormalities, and 8 (40%) had nonfrontotemporal abnormalities. Correlations between neuropsychologic testing and dynamic imaging could be established but not consistently across the whole group. Patients with mild TBI and persistent postconcussive symptoms have a high incidence of temporal lobe injury (presumably involving the hippocampus and related structures), which may explain the frequent finding of memory disorders in this population. The abnormal temporal lobe findings on PET and SPECT in humans may be analogous to the neuropathologic evidence of medial temporal injury provided by animal studies after mild TBI. Copyright 2002 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation

  19. Pre-2014 mudslides at Oso revealed by InSAR and multi-source DEM analysis

    Science.gov (United States)

    Kim, J. W.; Lu, Z.; QU, F.

    2014-12-01

    The landslide is a process that results in the downward and outward movement of slope-reshaping materials including rocks and soils and annually causes the loss of approximately $3.5 billion and tens of casualties in the United States. The 2014 Oso mudslide was an extreme event costing nearly 40 deaths and damaging civilian properties. Landslides are often unpredictable, but in many cases, catastrophic events are repetitive. Historic record in the Oso mudslide site indicates that there have been serial events in decades, though the extent of sliding events varied from time to time. In our study, the combination of multi-source DEMs, InSAR, and time-series InSAR analysis has enabled to characterize the Oso mudslide. InSAR results from ALOS PALSAR show that there was no significant deformation between mid-2006 and 2011. The combination of time-series InSAR analysis and old-dated DEM indicated revealed topographic changes associated the 2006 sliding event, which is confirmed by the difference of multiple LiDAR DEMs. Precipitation and discharge measurements before the 2006 and 2014 landslide events did not exhibit extremely anomalous records, suggesting the precipitation is not the controlling factor in determining the sliding events at Oso. The lack of surface deformation during 2006-2011 and weak correlation between the precipitation and the sliding event, suggest other factors (such as porosity) might play a critical role on the run-away events at this Oso and other similar landslides.

  20. Monitoring Volcano Deformation in the Northernmost Andes with ALOS InSAR Time-Series

    Science.gov (United States)

    Morales Rivera, A. M.; Amelung, F.

    2014-12-01

    Satellite-based Interferometric Synthetic Aperture Radar (InSAR) is well known to be used as a volcano monitoring tool, providing the opportunity to conduct local and regional surveys to detect and measure volcanic deformation. The signals detected by InSAR on volcanoes can be related to various phenomena, such as volume changes in magmatic reservoirs, compaction of recent deposits, changes in hydrothermal activity, and flank instability. The InSAR time-series method has well documented examples of these phenomena, including precursory inflation of magma reservoirs months prior to volcanic eruptions, proving its potential for early warning systems. We use the ALOS-1 satellite from the Japanese Aerospace Exploration Agency (JAXA), which acquired a global L-band data set of nearly 20 acquisitions during 2007-2011, to make an InSAR time-series analysis using the Small Baseline method (SBAS). Our analysis covers all of the volcanoes in Colombia, Ecuador, and Peru that are cataloged by the Global Volcanism Program. We present results showing time-dependent ground deformation on an near the volcanoes, and present kinematic models to constrain the characteristics of the magmatic sources for the cases in which the deformation is likely related to changes in magma reservoir pressurization.

  1. The management of scarce water resources using GNSS, InSAR ...

    African Journals Online (AJOL)

    GNSS receivers were run continuously for a period of 133 days between March and August 2014 to detect possible surface subsidence during pumping and artesian free flow extraction of water in the wellfield. Two InSAR scenes were processed, one during the peak period of water extraction from the wellfield and the other ...

  2. Imaging phase slip dynamics in micron-size superconducting rings

    Science.gov (United States)

    Polshyn, Hryhoriy; Naibert, Tyler R.; Budakian, Raffi

    2018-05-01

    We present a scanning probe technique for measuring the dynamics of individual fluxoid transitions in multiply connected superconducting structures. In these measurements, a small magnetic particle attached to the tip of a silicon cantilever is scanned over a micron-size superconducting ring fabricated from a thin aluminum film. We find that near the superconducting transition temperature of the aluminum, the dissipation and frequency of the cantilever changes significantly at particular locations where the tip-induced magnetic flux penetrating the ring causes the two lowest-energy fluxoid states to become nearly degenerate. In this regime, we show that changes in the cantilever frequency and dissipation are well-described by a stochastic resonance (SR) process, wherein small oscillations of the cantilever in the presence of thermally activated phase slips (TAPS) in the ring give rise to a dynamical force that modifies the mechanical properties of the cantilever. Using the SR model, we calculate the average fluctuation rate of the TAPS as a function of temperature over a 32-dB range in frequency, and we compare it to the Langer-Ambegaokar-McCumber-Halperin theory for TAPS in one-dimensional superconducting structures.

  3. Dynamic radionuclide imaging with 99mTc-sucralfate in the detection of oesophageal ulceration.

    Science.gov (United States)

    Mearns, A J; Hart, G C; Cox, J A

    1989-01-01

    Standard oesophageal scintigraphic techniques using 99mTc-colloids rarely identify oesophageal mucosal damage. Sucralfate can be labelled with 99mTc for the detection of oesophageal mucosal ulceration. This method uses two separate supine swallows of 10 MBq 99mTc-colloid in 10 ml, followed by a single supine swallow of 30 MBq 99mTc-sucralfate. The data are processed to give time-activity curves, mean transit times and condensed dynamic images. When oesophageal ulceration is detected, the time-activity curves using sucralfate show residual activity in the oesophagus after the transit time indicated by the colloid swallow. The condensed dynamic image shows a persistence of activity at the level of the ulceration. Erect sucralfate images taken immediately after the dynamic sequence show no oesophageal localisation. The results from a study of 62 patients have shown excellent correlation between the dynamic 99mTc-sucralfate images and endoscopy findings. Sequential sucralfate studies for healing also correlate well. The use of labelled sucralfate to detect oesophageal ulceration could modify the indications for endoscopy in gastrooesophageal reflux disease. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 PMID:2806994

  4. Generation of complete electronic nuclear medicine reports including static, dynamic and gated images

    International Nuclear Information System (INIS)

    Beretta, M.; Pilon, R.; Mut, F.

    2002-01-01

    Aim: To develop a procedure for the creation of nuclear medicine reports containing static and dynamic images. The reason for implementing this technique is the lack of adequate solutions for an electronic format of nuclear medicine results allowing for rapid transmission via e-mail, specially in the case of dynamic and gated SPECT studies, since functional data is best presented in dynamic mode. Material and Methods: Clinical images were acquired in static, whole body, dynamic and gated mode, corresponding to bone studies, diuretic renogram, radionuclide cystography and gated perfusion SPECT, as well as respective time-activity curves. Image files were imported from a dedicated nuclear medicine computer system (Elscint XPert) to a Windows-based PC through a standard ethernet network with TCP-IP communications protocol, using a software developed by us which permits the conversion from the manufacturer's original format into a bitmap format (.bmp) compatible with commercially available PC software. For cardiac perfusion studies, background was subtracted prior to transferring to reduce the amount of information in the file; this was not done for other type of studies because useful data could be eliminated. Dynamic images were then processed using commercial software to create animated files and stored in .gif format. Static images were re-sized and stored in .jpg format. Original color or gray scale was always preserved. All the graphic material was then merged with a previously prepared report text using HTML format. The report also contained reference diagrams to facilitate interpretation. The whole report was then compressed into a self-extractable file, ready to be sent by electronic mail. Reception of the material was visually checked for data integrity including image quality by two experienced nuclear medicine physicians. Results: The report presented allows for simultaneous visualization of the text, diagrams and images either static, dynamic, gated or

  5. Advanced Corrections for InSAR Using GPS and Numerical Weather Models

    Science.gov (United States)

    Cossu, F.; Foster, J. H.; Amelung, F.; Varugu, B. K.; Businger, S.; Cherubini, T.

    2017-12-01

    We present results from an investigation into the application of numerical weather models for generating tropospheric correction fields for Interferometric Synthetic Aperture Radar (InSAR). We apply the technique to data acquired from a UAVSAR campaign as well as from the CosmoSkyMed satellites. The complex spatial and temporal changes in the atmospheric propagation delay of the radar signal remain the single biggest factor limiting InSAR's potential for hazard monitoring and mitigation. A new generation of InSAR systems is being built and launched, and optimizing the science and hazard applications of these systems requires advanced methodologies to mitigate tropospheric noise. We use the Weather Research and Forecasting (WRF) model to generate a 900 m spatial resolution atmospheric models covering the Big Island of Hawaii and an even higher, 300 m resolution grid over the Mauna Loa and Kilauea volcanoes. By comparing a range of approaches, from the simplest, using reanalyses based on typically available meteorological observations, through to the "kitchen-sink" approach of assimilating all relevant data sets into our custom analyses, we examine the impact of the additional data sets on the atmospheric models and their effectiveness in correcting InSAR data. We focus particularly on the assimilation of information from the more than 60 GPS sites in the island. We ingest zenith tropospheric delay estimates from these sites directly into the WRF analyses, and also perform double-difference tomography using the phase residuals from the GPS processing to robustly incorporate heterogeneous information from the GPS data into the atmospheric models. We assess our performance through comparisons of our atmospheric models with external observations not ingested into the model, and through the effectiveness of the derived phase screens in reducing InSAR variance. Comparison of the InSAR data, our atmospheric analyses, and assessments of the active local and mesoscale

  6. Seven years of postseismic deformation following the 2003 Mw = 6.8 Zemmouri earthquake (Algeria) from InSAR time series

    KAUST Repository

    Cetin, Esra

    2012-05-28

    We study the postseismic surface deformation of the Mw 6.8, 2003 Zemmouri earthquake (northern Algeria) using the Multi-Temporal Small Baseline InSAR technique. InSAR time series obtained from 31 Envisat ASAR images from 2003 to 2010 reveal sub-cm coastline ground movements between Cap Matifou and Dellys. Two regions display subsidence at a maximum rate of 2 mm/yr in Cap Djenet and 3.5 mm/yr in Boumerdes. These regions correlate well with areas of maximum coseismic uplifts, and their association with two rupture segments. Inverse modeling suggest that subsidence in the areas of high coseismic uplift can be explained by afterslip on shallow sections (<5 km) of the fault above the areas of coseismic slip, in agreement with previous GPS observations. The earthquake impact on soft sediments and the ground water table southwest of the earthquake area, characterizes ground deformation of non-tectonic origin. The cumulative postseismic moment due to 7 years afterslip is equivalent to an Mw 6.3 earthquake. Therefore, the postseismic deformation and stress buildup has significant implications on the earthquake cycle models and recurrence intervals of large earthquakes in the Algiers area.

  7. Integration of InSAR and GIS in the Study of Surface Faults Caused by Subsidence-Creep-Fault Processes in Celaya, Guanajuato, Mexico

    International Nuclear Information System (INIS)

    Avila-Olivera, Jorge A.; Farina, Paolo; Garduno-Monroy, Victor H.

    2008-01-01

    In Celaya city, Subsidence-Creep-Fault Processes (SCFP) began to become visible at the beginning of the 1980s with the sprouting of the crackings that gave rise to the surface faults 'Oriente' and 'Poniente'. At the present time, the city is being affected by five surface faults that display a preferential NNW-SSE direction, parallel to the regional faulting system 'Taxco-San Miguel de Allende'. In order to study the SCFP in the city, the first step was to obtain a map of surface faults, by integrating in a GIS field survey and an urban city plan. The following step was to create a map of the current phreatic level decline in city with the information of deep wells and using the 'kriging' method in order to obtain a continuous surface. Finally the interferograms maps resulted of an InSAR analysis of 9 SAR images covering the time interval between July 12 of 2003 and May 27 of 2006 were integrated to a GIS. All the maps generated, show how the surface faults divide the city from North to South, in two zones that behave in a different way. The difference of the phreatic level decline between these two zones is 60 m; and the InSAR study revealed that the Western zone practically remains stable, while sinkings between the surface faults 'Oriente' and 'Universidad Pedagogica' are present, as well as in portions NE and SE of the city, all of these sinkings between 7 and 10 cm/year

  8. Seven years of postseismic deformation following the 2003 Mw = 6.8 Zemmouri earthquake (Algeria) from InSAR time series

    KAUST Repository

    Cetin, Esra; Meghraoui, Mustapha; Cakir, Ziyadin; Akoglu, Ahmet M.; Mimouni, Omar; Chebbah, Mouloud

    2012-01-01

    We study the postseismic surface deformation of the Mw 6.8, 2003 Zemmouri earthquake (northern Algeria) using the Multi-Temporal Small Baseline InSAR technique. InSAR time series obtained from 31 Envisat ASAR images from 2003 to 2010 reveal sub-cm coastline ground movements between Cap Matifou and Dellys. Two regions display subsidence at a maximum rate of 2 mm/yr in Cap Djenet and 3.5 mm/yr in Boumerdes. These regions correlate well with areas of maximum coseismic uplifts, and their association with two rupture segments. Inverse modeling suggest that subsidence in the areas of high coseismic uplift can be explained by afterslip on shallow sections (<5 km) of the fault above the areas of coseismic slip, in agreement with previous GPS observations. The earthquake impact on soft sediments and the ground water table southwest of the earthquake area, characterizes ground deformation of non-tectonic origin. The cumulative postseismic moment due to 7 years afterslip is equivalent to an Mw 6.3 earthquake. Therefore, the postseismic deformation and stress buildup has significant implications on the earthquake cycle models and recurrence intervals of large earthquakes in the Algiers area.

  9. Context-dependent JPEG backward-compatible high-dynamic range image compression

    Science.gov (United States)

    Korshunov, Pavel; Ebrahimi, Touradj

    2013-10-01

    High-dynamic range (HDR) imaging is expected, together with ultrahigh definition and high-frame rate video, to become a technology that may change photo, TV, and film industries. Many cameras and displays capable of capturing and rendering both HDR images and video are already available in the market. The popularity and full-public adoption of HDR content is, however, hindered by the lack of standards in evaluation of quality, file formats, and compression, as well as large legacy base of low-dynamic range (LDR) displays that are unable to render HDR. To facilitate the wide spread of HDR usage, the backward compatibility of HDR with commonly used legacy technologies for storage, rendering, and compression of video and images are necessary. Although many tone-mapping algorithms are developed for generating viewable LDR content from HDR, there is no consensus of which algorithm to use and under which conditions. We, via a series of subjective evaluations, demonstrate the dependency of the perceptual quality of the tone-mapped LDR images on the context: environmental factors, display parameters, and image content itself. Based on the results of subjective tests, it proposes to extend JPEG file format, the most popular image format, in a backward compatible manner to deal with HDR images also. An architecture to achieve such backward compatibility with JPEG is proposed. A simple implementation of lossy compression demonstrates the efficiency of the proposed architecture compared with the state-of-the-art HDR image compression.

  10. Some imaging characteristics of the dynamic spatial reconstructor X-ray scanner system

    International Nuclear Information System (INIS)

    Behrenbeck, T.; Sinak, L.J.; Robb, R.A.; Kinsey, J.H.; Ritman, E.L.

    1984-01-01

    In late 1979, the Dynamic Spatial Reconstructor (DSR), a multiple X-ray source, stop action, volume scanning imaging device was installed. At present, the operational characteristics and biomedical utility of the DSR are being evaluated. This research project involves scanning experimental animals and carefully selected patients with cardiovascular and pulmonary pathology. The DSR scanner utilizes a computerized transaxial tomography principle to generate images of transverse slices of the body. (Auth.)

  11. Automatic segmentation of dynamic neuroreceptor single-photon emission tomography images using fuzzy clustering

    International Nuclear Information System (INIS)

    Acton, P.D.; Pilowsky, L.S.; Kung, H.F.; Ell, P.J.

    1999-01-01

    The segmentation of medical images is one of the most important steps in the analysis and quantification of imaging data. However, partial volume artefacts make accurate tissue boundary definition difficult, particularly for images with lower resolution commonly used in nuclear medicine. In single-photon emission tomography (SPET) neuroreceptor studies, areas of specific binding are usually delineated by manually drawing regions of interest (ROIs), a time-consuming and subjective process. This paper applies the technique of fuzzy c-means clustering (FCM) to automatically segment dynamic neuroreceptor SPET images. Fuzzy clustering was tested using a realistic, computer-generated, dynamic SPET phantom derived from segmenting an MR image of an anthropomorphic brain phantom. Also, the utility of applying FCM to real clinical data was assessed by comparison against conventional ROI analysis of iodine-123 iodobenzamide (IBZM) binding to dopamine D 2 /D 3 receptors in the brains of humans. In addition, a further test of the methodology was assessed by applying FCM segmentation to [ 123 I]IDAM images (5-iodo-2-[[2-2-[(dimethylamino)methyl]phenyl]thio] benzyl alcohol) of serotonin transporters in non-human primates. In the simulated dynamic SPET phantom, over a wide range of counts and ratios of specific binding to background, FCM correlated very strongly with the true counts (correlation coefficient r 2 >0.99, P 123 I]IBZM data comparable with manual ROI analysis, with the binding ratios derived from both methods significantly correlated (r 2 =0.83, P<0.0001). Fuzzy clustering is a powerful tool for the automatic, unsupervised segmentation of dynamic neuroreceptor SPET images. Where other automated techniques fail completely, and manual ROI definition would be highly subjective, FCM is capable of segmenting noisy images in a robust and repeatable manner. (orig.)

  12. Registration of dynamic dopamine D{sub 2}receptor images using principal component analysis

    Energy Technology Data Exchange (ETDEWEB)

    Acton, P.D.; Ell, P.J. [Institute of Nuclear Medicine, University College London Medical School, London (United Kingdom); Pilowsky, L.S.; Brammer, M.J. [Institute of Psychiatry, De Crespigny Park, London (United Kingdom); Suckling, J. [Clinical Age Research Unit, Kings College School of Medicine and Dentistry, London (United Kingdom)

    1997-11-01

    This paper describes a novel technique for registering a dynamic sequence of single-photon emission tomography (SPET) dopamine D{sub 2}receptor images, using principal component analysis (PCA). Conventional methods for registering images, such as count difference and correlation coefficient algorithms, fail to take into account the dynamic nature of the data, resulting in large systematic errors when registering time-varying images. However, by using principal component analysis to extract the temporal structure of the image sequence, misregistration can be quantified by examining the distribution of eigenvalues. The registration procedures were tested using a computer-generated dynamic phantom derived from a high-resolution magnetic resonance image of a realistic brain phantom. Each method was also applied to clinical SPET images of dopamine D {sub 2}receptors, using the ligands iodine-123 iodobenzamide and iodine-123 epidepride, to investigate the influence of misregistration on kinetic modelling parameters and the binding potential. The PCA technique gave highly significant (P <0.001) improvements in image registration, leading to alignment errors in x and y of about 25% of the alternative methods, with reductions in autocorrelations over time. It could also be applied to align image sequences which the other methods failed completely to register, particularly {sup 123}I-epidepride scans. The PCA method produced data of much greater quality for subsequent kinetic modelling, with an improvement of nearly 50% in the {chi}{sup 2}of the fit to the compartmental model, and provided superior quality registration of particularly difficult dynamic sequences. (orig.) With 4 figs., 2 tabs., 26 refs.

  13. A digital-signal-processor-based optical tomographic system for dynamic imaging of joint diseases

    Science.gov (United States)

    Lasker, Joseph M.

    Over the last decade, optical tomography (OT) has emerged as viable biomedical imaging modality. Various imaging systems have been developed that are employed in preclinical as well as clinical studies, mostly targeting breast imaging, brain imaging, and cancer related studies. Of particular interest are so-called dynamic imaging studies where one attempts to image changes in optical properties and/or physiological parameters as they occur during a system perturbation. To successfully perform dynamic imaging studies, great effort is put towards system development that offers increasingly enhanced signal-to-noise performance at ever shorter data acquisition times, thus capturing high fidelity tomographic data within narrower time periods. Towards this goal, I have developed in this thesis a dynamic optical tomography system that is, unlike currently available analog instrumentation, based on digital data acquisition and filtering techniques. At the core of this instrument is a digital signal processor (DSP) that collects, collates, and processes the digitized data set. Complementary protocols between the DSP and a complex programmable logic device synchronizes the sampling process and organizes data flow. Instrument control is implemented through a comprehensive graphical user interface which integrates automated calibration, data acquisition, and signal post-processing. Real-time data is generated at frame rates as high as 140 Hz. An extensive dynamic range (˜190 dB) accommodates a wide scope of measurement geometries and tissue types. Performance analysis demonstrates very low system noise (˜1 pW rms noise equivalent power), excellent signal precision (˜0.04%--0.2%) and long term system stability (˜1% over 40 min). Experiments on tissue phantoms validate spatial and temporal accuracy of the system. As a potential new application of dynamic optical imaging I present the first application of this method to use vascular hemodynamics as a means of characterizing

  14. 3.5D dynamic PET image reconstruction incorporating kinetics-based clusters

    International Nuclear Information System (INIS)

    Lu Lijun; Chen Wufan; Karakatsanis, Nicolas A; Rahmim, Arman; Tang Jing

    2012-01-01

    Standard 3D dynamic positron emission tomographic (PET) imaging consists of independent image reconstructions of individual frames followed by application of appropriate kinetic model to the time activity curves at the voxel or region-of-interest (ROI). The emerging field of 4D PET reconstruction, by contrast, seeks to move beyond this scheme and incorporate information from multiple frames within the image reconstruction task. Here we propose a novel reconstruction framework aiming to enhance quantitative accuracy of parametric images via introduction of priors based on voxel kinetics, as generated via clustering of preliminary reconstructed dynamic images to define clustered neighborhoods of voxels with similar kinetics. This is then followed by straightforward maximum a posteriori (MAP) 3D PET reconstruction as applied to individual frames; and as such the method is labeled ‘3.5D’ image reconstruction. The use of cluster-based priors has the advantage of further enhancing quantitative performance in dynamic PET imaging, because: (a) there are typically more voxels in clusters than in conventional local neighborhoods, and (b) neighboring voxels with distinct kinetics are less likely to be clustered together. Using realistic simulated 11 C-raclopride dynamic PET data, the quantitative performance of the proposed method was investigated. Parametric distribution-volume (DV) and DV ratio (DVR) images were estimated from dynamic image reconstructions using (a) maximum-likelihood expectation maximization (MLEM), and MAP reconstructions using (b) the quadratic prior (QP-MAP), (c) the Green prior (GP-MAP) and (d, e) two proposed cluster-based priors (CP-U-MAP and CP-W-MAP), followed by graphical modeling, and were qualitatively and quantitatively compared for 11 ROIs. Overall, the proposed dynamic PET reconstruction methodology resulted in substantial visual as well as quantitative accuracy improvements (in terms of noise versus bias performance) for parametric DV

  15. TH-A-18C-10: Dynamic Intensity Weighted Region of Interest Imaging

    International Nuclear Information System (INIS)

    Pearson, E; Pan, X; Pelizzari, C

    2014-01-01

    Purpose: For image guidance tasks full image quality is not required throughout the entire image. With dynamic filtration of the kV imaging beam the noise properties of the CT image can be locally controlled, providing a high quality image around the target volume with a lower quality surrounding region while providing substantial dose sparing to the patient as well as reduced scatter fluence on the detector. Methods: A dynamic collimation device with 3mm copper blades has been designed to mount in place of the bowtie filter on the On-Board Imager (Varian Medical Systems). The beam intensity is reduced by 95% behind the copper filters and the aperture is controlled dynamically to conformally illuminate a given ROI during a standard cone-beam CT scan. A data correction framework to account for the physical effects of the collimator prior to reconstruction was developed. Furthermore, to determine the dose savings and scatter reduction a monte carlo model was built in BEAMnrc with specifics from the Varian Monte Carlo Data Package. The MC model was validated with Gafchromic film. Results: The reconstructed image shows image quality comparable to a standard scan in the specified ROI, with higher noise and streaks in the outer region but still sufficient information for alignment to high contrast structures. The monte carlo modeling showed that the scatter-to-primary ratio was reduced from 1.26 for an unfiltered scan to 0.45 for an intensity weighted scan, suggesting that image quality may be improved in the inner ROI. Dose in the inner region was reduced 10–15% due to reduced scatter and by as much as 75% in the outer region. Conclusion: Dynamic intensity-weighted ROI imaging allows reduction of imaging dose to sensitive organs away from the target region while providing images that retain their utility for patient setup and procedure guidance. Funding was provided in part by Varian Medical Systems and NIH Grants 1RO1CA120540, T32EB002103, S10 RR021039 and P30 CA

  16. Spot Sign in Acute Intracerebral Hemorrhage in Dynamic T1-Weighted Magnetic Resonance Imaging.

    Science.gov (United States)

    Schindlbeck, Katharina A; Santaella, Anna; Galinovic, Ivana; Krause, Thomas; Rocco, Andrea; Nolte, Christian H; Villringer, Kersten; Fiebach, Jochen B

    2016-02-01

    In computed tomographic imaging of acute intracerebral hemorrhage spot sign on computed tomographic angiography has been established as a marker for hematoma expansion and poor clinical outcome. Although, magnetic resonance imaging (MRI) can accurately visualize acute intracerebral hemorrhage, a corresponding MRI marker is lacking to date. We prospectively examined 50 consecutive patients with acute intracerebral hemorrhage within 24 hours of symptom onset. The MRI protocol consisted of a standard stroke protocol and dynamic contrast-enhanced T1-weighted imaging with a time resolution of 7.07 s/batch. Stroke scores were assessed at admission and at time of discharge. Volume measurements of hematoma size and spot sign were performed with MRIcron. Contrast extravasation within sites of the hemorrhage (MRI spot sign) was seen in 46% of the patients. Patients with an MRI spot sign had a significantly shorter time to imaging than those without (Pspot sign compared with those without (P≤0.001). Hematoma expansion was observed in the spot sign group compared with the nonspot sign group, although the differences were not significant. Spot sign can be detected using MRI on postcontrast T1-weighted and dynamic T1-weighted images. It is associated with worse clinical outcome. The time course of contrast extravasation in dynamic T1 images indicates that these spots represent ongoing bleeding. © 2015 American Heart Association, Inc.

  17. Quadrant Dynamic with Automatic Plateau Limit Histogram Equalization for Image Enhancement

    Directory of Open Access Journals (Sweden)

    P. Jagatheeswari

    2014-01-01

    Full Text Available The fundamental and important preprocessing stage in image processing is the image contrast enhancement technique. Histogram equalization is an effective contrast enhancement technique. In this paper, a histogram equalization based technique called quadrant dynamic with automatic plateau limit histogram equalization (QDAPLHE is introduced. In this method, a hybrid of dynamic and clipped histogram equalization methods are used to increase the brightness preservation and to reduce the overenhancement. Initially, the proposed QDAPLHE algorithm passes the input image through a median filter to remove the noises present in the image. Then the histogram of the filtered image is divided into four subhistograms while maintaining second separated point as the mean brightness. Then the clipping process is implemented by calculating automatically the plateau limit as the clipped level. The clipped portion of the histogram is modified to reduce the loss of image intensity value. Finally the clipped portion is redistributed uniformly to the entire dynamic range and the conventional histogram equalization is executed in each subhistogram independently. Based on the qualitative and the quantitative analysis, the QDAPLHE method outperforms some existing methods in literature.

  18. Deep HST Imaging in 47 Tucanae: A Global Dynamical Model

    Science.gov (United States)

    Heyl, J.; Caiazzo, I.; Richer, H.; Anderson, J.; Kalirai, J.; Parada, J.

    2017-12-01

    Multi-epoch observations with the Advanced Camera Survey and WFC3 on the Hubble Space Telescope provide a unique and comprehensive probe of stellar dynamics within 47 Tucanae. We confront analytic models of the globular cluster with the observed stellar proper motions that probe along the main sequence from just above 0.8-0.1M ⊙ as well as white dwarfs younger than 1 Gyr. One field lies just beyond the half-light radius where dynamical models (e.g., lowered Maxwellian distributions) make robust predictions for the stellar proper motions. The observed proper motions in this outer field show evidence for anisotropy in the velocity distribution as well as skewness; the latter is evidence of rotation. The measured velocity dispersions and surface brightness distributions agree in detail with a rotating anisotropic model of the stellar distribution function with mild dependence of the proper-motion dispersion on mass. However, the best-fitting models underpredict the rotation and skewness of the stellar velocities. In the second field, centered on the core of the cluster, the mass segregation in proper motion is much stronger. Nevertheless the model developed in the outer field can be extended inward by taking this mass segregation into account in a heuristic fashion. The proper motions of the main-sequence stars yield a mass estimate of the cluster of 1.31+/- 0.02× {10}6{M}⊙ at a distance of 4.7 kpc. By comparing the proper motions of a sample of giant and subgiant stars with the observed radial velocities we estimate the distance to the cluster kinematically to be 4.29 ± 0.47 kpc.

  19. Answering the right question - integration of InSAR with other datasets

    Science.gov (United States)

    Holley, Rachel; McCormack, Harry; Burren, Richard

    2014-05-01

    The capabilities of satellite Interferometric Synthetic Aperture Radar (InSAR) are well known, and utilized across a wide range of academic and commercial applications. However there is a tendency, particularly in commercial applications, for users to ask 'What can we study with InSAR?'. When establishing a new technique this approach is important, but InSAR has been possible for 20 years now and, even accounting for new and innovative algorithms, this ground has been thoroughly explored. Too many studies conclude 'We show the ground is moving here, by this much', and mention the wider context as an afterthought. The focus needs to shift towards first asking the right questions - in fields as diverse as hazard awareness, resource optimization, financial considerations and pure scientific enquiry - and then working out how to achieve the best possible answers. Depending on the question, InSAR (and ground deformation more generally) may provide a large or small contribution to the overall solution, and there are usually benefits to integrating a number of techniques to capitalize on the complementary capabilities and provide the most useful measurements. However, there is still a gap between measurements and answers, and unlocking the value of the data relies heavily on appropriate visualization, integrated analysis, communication between technique and application experts, and appropriate use of modelling. We present a number of application examples, and demonstrate how their usefulness can be transformed by moving from a focus on data to answers - integrating complementary geodetic, geophysical and geological datasets and geophysical modeling with appropriate visualization, to enable comprehensive solution-focused interpretation. It will also discuss how forthcoming developments are likely to further advance realisation of the full potential satellite InSAR holds.

  20. Crustal Deformation along San Andreas Fault System revealed by GPS and Sentinel-1 InSAR

    Science.gov (United States)

    Xu, X.; Sandwell, D. T.

    2017-12-01

    We present a crustal deformation velocity map along the San Andreas Fault System by combining measurements from Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) velocity models (CGM V1). We assembled 5 tracks of descending Sentinel-1 InSAR data spanning 2014.11-2017.02, and produced 545 interferograms, each of which covers roughly 250km x 420km area ( 60 bursts). These interferograms are unwrapped using SNAPHU [Chen & Zebker, 2002], with the 2Npi unwrapping ambiguity corrected with a sparse recovery method. We used coherence-based small baseline subset (SBAS) method [Tong & Schmidt, 2016] together with atmospheric correction by common-point stacking [Tymofyeyeva and Fialko, 2015] to construct deformation time series [Xu et. al., 2017]. Then we project the horizontal GPS model and vertical GPS data into satellite line-of-sight directions separately. We first remove the horizontal GPS model from InSAR measurements and perform elevation-dependent atmospheric phase correction. Then we compute the discrepancy between the remaining InSAR measurements and vertical GPS data. We interpolate this discrepancy and remove it from the residual InSAR measurements. Finally, we restore the horizontal GPS model. Preliminary results show that fault creep over the San Jacinto fault, the Elsinore fault, and the San Andreas creeping section is clearly resolved. During the period of drought, the Central Valley of California was subsiding at a high rate (up to 40 cm/yr), while the city of San Jose is uplifting due to recharge, with a quaternary fault acting as a ground water barrier. These findings will be reported during the meeting.

  1. Contrast-enhanced dynamic MR imaging in rheumatoid arthritis

    International Nuclear Information System (INIS)

    Koenig, H.; Sieper, J.; Wolf, K.J.

    1989-01-01

    This paper reports on a study for the identification of different pannus formations. Twenty patients with advanced rheumatoid arthritis of the knee joint were examined with MR imaging primary to surgery. The authors used a 1.5-T Magnetom unit, a circular surface coil for signal detection, 0.1 mmol/kg of Gd-DTPA given as a bolus injection, fast low-angle shot (FLASH) sequence (TR, 30 msec; TE, 10 msec; 128 x 128 matrix; excitation angle, 70 degrees) repeated 30 times within 120 seconds, and a T1-weighted spin-echo sequence (Tr, 500 msec; TE, 22 msec) before and 2 minutes after contrast medium injection. Enhancement of pannus and joint effusion has been measured and standardized to muscle tissue

  2. Dynamic imaging for CAR-T-cell therapy.

    Science.gov (United States)

    Emami-Shahri, Nia; Papa, Sophie

    2016-04-15

    Chimaeric antigen receptor (CAR) therapy is entering the mainstream for the treatment of CD19(+)cancers. As is does we learn more about resistance to therapy and the role, risks and management of toxicity. In solid tumour CAR therapy research the route to the clinic is less smooth with a wealth of challenges facing translating this, potentially hugely valuable, therapeutic option for patients. As we strive to understand our successes, and navigate the challenges, having a clear understanding of how adoptively transferred CAR-T-cells behavein vivoand in human trials is invaluable. Harnessing reporter gene imaging to enable detection and tracking of small numbers of CAR-T-cells after adoptive transfer is one way by which we can accomplish this. The compatibility of certain reporter gene systems with tracers available routinely in the clinic makes this approach highly useful for future appraisal of CAR-T-cell success in humans. © 2016 Authors; published by Portland Press Limited.

  3. Preoperative chemotherapy of bone and soft tissue sarcomas. Evaluation with dynamic MR imaging

    International Nuclear Information System (INIS)

    Ando, Yoko; Fukatsu, Hiroshi; Isomura, Takayuki; Itoh, Shigeki; Ishigaki, Takeo; Yamamura, Shigeki; Sugiura, Hideshi; Satoh, Keiji.

    1995-01-01

    Dynamic MR imaging and conventional angiography were performed in eleven patients with musculoskeletal malignant tumors before and after preoperative chemotherapy in order to evaluate its effect. Dynamic MRI was obtained with GRASS (TR/TE/FA=50/10-13/30) or SE (TR/TE=150-350/20). Although resected specimen in one case of osteosarcoma had the necrotic ratio of more than 90%, it had marked early enhancement in dynamic MRI, and microscopic examination revealed fibrotic necrosis with many capillaries. In soft tissue sarcomas with hemorrhage and/or cystic change, dynamic MRI findings did not necessarily correlate with the chemotherapy effect. Dynamic MRI was more useful than angiography because of its ability to show tumor vascularity and of its non-invasiveness. (author)

  4. Time-resolved imaging of purely valence-electron dynamics during a chemical reaction

    DEFF Research Database (Denmark)

    Hockett, Paul; Bisgaard, Christer Z.; Clarkin, Owen J.

    2011-01-01

    Chemical reactions are manifestations of the dynamics of molecular valence electrons and their couplings to atomic motions. Emerging methods in attosecond science can probe purely electronic dynamics in atomic and molecular systems(1-6). By contrast, time-resolved structural-dynamics methods...... such as electron(7-10) or X-ray diffraction(11) and X-ray absorption(12) yield complementary information about the atomic motions. Time-resolved methods that are directly sensitive to both valence-electron dynamics and atomic motions include photoelectron spectroscopy(13-15) and high-harmonic generation(16......,17): in both cases, this sensitivity derives from the ionization-matrix element(18,19). Here we demonstrate a time-resolved molecular-frame photoelectron-angular-distribution (TRMFPAD) method for imaging the purely valence-electron dynamics during a chemical reaction. Specifically, the TRMFPADs measured during...

  5. Statistical dynamic imaging of RI-labeled tracer from list-mode PET data

    International Nuclear Information System (INIS)

    Tanimoto, Michiaki; Kuroda, Yoshihiro; Oshiro, Osamu; Watabe, Hiroshi; Kuroda, Tomohiro

    2009-01-01

    Positron emission tomography (PET) can be used in physiological analysis to illustrate physiological states by visualizing the accumulation of radioisotope (RI)-labeled tracer in specific organs or tissues. PET obtains spatio-temporal statistics in the form of list-mode data. However, conventional imaging techniques, which sum up list-mode data over a given time period, cannot depict detailed temporal dynamics of the RI-labeled tracer. In this study, a spatio-temporal analysis approach was employed to visualize the temporal flow dynamics of RI-labeled tracer from the obtained list-mode data. Experiments to assess the visualization of simulated RI-labeled tracer dynamics as well as RI-labeled tracer dynamics in a vascular phantom showed that the proposed method successfully depicted detailed temporal flow dynamics that could not be visualized using conventional methods. (author)

  6. A systematic desaturation method for images from the Atmospheric Imaging Assembly in the Solar Dynamics Observatory.

    Science.gov (United States)

    Torre, Gabriele; Schwartz, Richard; Piana, Michele; Massone, Anna Maria; Benvenuto, Federico

    2016-05-01

    The fine spatial resolution of the SDO AIA CCD's is often destroyed by the charge in saturated pixels overflowing into a swath of neighboring cells during fast rising solar flares. Automated exposure control can only mitigate this issue to a degree and it has other deleterious effects. Our method addresses the desaturation problem for AIA images as an image reconstruction problem in which the information content of the diffraction fringes, generated by the interaction between the incoming radiation and the hardware of the spacecraft, is exploited to recover the true image intensities within the primary saturated core of the image. This methodology takes advantage of some well defined techniques like cross-correlation and the Expectation Maximization method to invert the direct relation between the diffraction fringes intensities and the true flux intensities. During this talk a complete overview on the structure of the method will be provided, besides some reliability tests obtained by its application against synthetic and real data.

  7. Dynamics of annular bright field imaging in scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    Findlay, S.D.; Shibata, N.; Sawada, H.; Okunishi, E.; Kondo, Y.; Ikuhara, Y.

    2010-01-01

    We explore the dynamics of image formation in the so-called annular bright field mode in scanning transmission electron microscopy, whereby an annular detector is used with detector collection range lying within the cone of illumination, i.e. the bright field region. We show that this imaging mode allows us to reliably image both light and heavy columns over a range of thickness and defocus values, and we explain the contrast mechanisms involved. The role of probe and detector aperture sizes is considered, as is the sensitivity of the method to intercolumn spacing and local disorder.

  8. The usefulness of dynamic MR imaging for the evaluation of cervical cancer

    International Nuclear Information System (INIS)

    Yoon, Jeong Hee; Park, Yeong Mi

    2004-01-01

    We wished to evaluate the diagnostic usefulness of dynamic MRI in assessing tumor visualization and the parametrial invasion of cervical cancer, and we also wished to determine the most adequate enhancing time by comparing the T2-weighted image (T2WI) and enhanced T1-weighted image (Gd-T1WI). Fifty-three women with histopathologically proven cervical cancer underwent a preoperative MRI. Using a 1.5 T magnet, the fast spin echo axial T2WI without fat saturation was taken; after contrast administration, 20, 40, 60, 90, 120 sec-dynamic MRIs were taken using fast SPGR and spin echo axial Gd-T1WI. Tumor conspicuity and parametrial invasion in each pulse sequence and the most adequate enhancing time for the evaluation of the tumor on dynamic MRI were evaluated prospectively by three radiologists working at three separate sessions. The results were then correlated with the histopathologic findings. The conspicuity of tumor on dynamic MRI (99.4%) and T2WI (95.6%) were better than on Gd-T1WI (89.3%). In the assessment of parametrial invasion of the tumor, the diagnostic accuracy of dynamic MRI, Gd-T1WI and T2WI was 79.9%, 78% and 76.1%, respectively; the highest values were for the dynamic MRI, but there was no statistically significant difference among three pulse sequences. The most adequate enhancing time on dynamic MRI was between 90 seconds and 120 seconds. Dynamic MRI is useful for the assessment of tumor visualization of cervical cancer, and the most appropriate scan time on dynamic MRI is between 90 seconds and 120 seconds. For the determination of parametrial invasion, the dynamic MRI revealed a higher diagnostic accuracy than that of T2WI or Gd-T1WI, but the differences were statistically insignificant

  9. Facilitating in vivo tumor localization by principal component analysis based on dynamic fluorescence molecular imaging

    Science.gov (United States)

    Gao, Yang; Chen, Maomao; Wu, Junyu; Zhou, Yuan; Cai, Chuangjian; Wang, Daliang; Luo, Jianwen

    2017-09-01

    Fluorescence molecular imaging has been used to target tumors in mice with xenograft tumors. However, tumor imaging is largely distorted by the aggregation of fluorescent probes in the liver. A principal component analysis (PCA)-based strategy was applied on the in vivo dynamic fluorescence imaging results of three mice with xenograft tumors to facilitate tumor imaging, with the help of a tumor-specific fluorescent probe. Tumor-relevant features were extracted from the original images by PCA and represented by the principal component (PC) maps. The second principal component (PC2) map represented the tumor-related features, and the first principal component (PC1) map retained the original pharmacokinetic profiles, especially of the liver. The distribution patterns of the PC2 map of the tumor-bearing mice were in good agreement with the actual tumor location. The tumor-to-liver ratio and contrast-to-noise ratio were significantly higher on the PC2 map than on the original images, thus distinguishing the tumor from its nearby fluorescence noise of liver. The results suggest that the PC2 map could serve as a bioimaging marker to facilitate in vivo tumor localization, and dynamic fluorescence molecular imaging with PCA could be a valuable tool for future studies of in vivo tumor metabolism and progression.

  10. Multi-temporal InSAR monitoring of landslides in a tropical urban environment: focus on Bukavu (DR Congo)

    Science.gov (United States)

    Nobile, Adriano; Monsieurs, Elise; Dewitte, Olivier; d'Oreyes, Nicolas; Kervyn, Francois

    2016-04-01

    The western branch of the East African Rift System, in Central Africa, is characterized by the presence of several geohazards: earthquakes, volcanoes, and landslides. Every year, landslides cause fatalities, structural and functional damage to infrastructure and private properties with serious disruptions of the organization of societies and severe impact on the populations. These impacts are particularly important in the city of Bukavu (DR Congo) located within the Rift, on the southern shore of Lake Kivu. Large slow-moving landslides continuously affect highly populated slopes in the city. However little is known about their actual kinematics and the processes at play. Here we use multi-temporal InSAR technique to monitor these ground deformations. Using 50 Cosmo-SkyMed SAR images, acquired between March - October 2015 with a revisiting time of 8 days (ascending and descending orbits), we produce displacement-rate maps and ground deformation time series using the PS technique. Movements with a velocity >5cm/yr are detected, which is consistent with field observations. DGPS measurements, taken at 21 benchmarks in the area during the same period, allow validating the results. Similar ground deformation rates are found for the period 2002-2008 using Envisat ASAR images. Furthermore, comparison with rainfall monitoring data acquire on site should help us to understand the influence of water and the tropical seasonality in the slide mechanisms.

  11. Full-direct method for imaging pharmacokinetic parameters in dynamic fluorescence molecular tomography

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Guanglei, E-mail: guangleizhang@bjtu.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Department of Biomedical Engineering, School of Computer and Information Technology, Beijing Jiaotong University, Beijing 100044 (China); Pu, Huangsheng; Liu, Fei; Bai, Jing [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); He, Wei [China Institute of Sport Science, Beijing 100061 (China); Luo, Jianwen, E-mail: luo-jianwen@tsinghua.edu.cn [Department of Biomedical Engineering, School of Medicine, Tsinghua University, Beijing 100084 (China); Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing 100084 (China)

    2015-02-23

    Images of pharmacokinetic parameters (also known as parametric images) in dynamic fluorescence molecular tomography (FMT) can provide three-dimensional metabolic information for biological studies and drug development. However, the ill-posed nature of FMT and the high temporal variation of fluorophore concentration together make it difficult to obtain accurate parametric images in small animals in vivo. In this letter, we present a method to directly reconstruct the parametric images from the boundary measurements based on hybrid FMT/X-ray computed tomography (XCT) system. This method can not only utilize structural priors obtained from the XCT system to mitigate the ill-posedness of FMT but also make full use of the temporal correlations of boundary measurements to model the high temporal variation of fluorophore concentration. The results of numerical simulation and mouse experiment demonstrate that the proposed method leads to significant improvements in the reconstruction quality of parametric images.

  12. Skeletal remodeling dynamics: New approaches with imaging instrumentation

    International Nuclear Information System (INIS)

    Parks, N.J.; Pinkerton, K.E.; Seibert, J.A.; Pool, R.R.

    1991-01-01

    This report of progress and future objectives timetable is based on an included schematic of goals and objectives and the project abstract which is included as Appendix 1. Five matters are summarized in the order of (1) novel methods of calcified bone confocal microscopy and reconstruction image analysis of decalcified beagle and human cortical bone serial sections, (2) macroscopic cross-correlation of beagle and human cortical and cancellous bone fractions with CT analysis, (3) guidance to the most radiobiologically important skeletal regions of interest with the just completed 90 Sr bone tumor map from life time beagle studies, (4) deposition patterns of radioactive agents that participate in apatite crystal nucleation processes in bone and leave radiation-excited electrons trapped in bone mineral, and (5) the budget period timetable. The discovery that beta particles from 166 Ho (T 1/2 =26 hr, β max = 1.8 MeV) phosphonic acid bone agents leave detectable, long-lived, electron paramagnetic resonance signals in bone is included in Appendix 2 as a joint report

  13. [Functional magnetic resonance imaging and dynamic neuroanatomy of addictive disorders].

    Science.gov (United States)

    Mel'nikov, M E; Shtark, M B

    2014-01-01

    Research into the cerebral patterns that govern the formation and development of addictive behavior is one of the most interesting goals of neurophysiology. Authors of contemporary papers on the matter define a number of symptoms that are all part of substance or non-substance dependence, each one of them leading to abnormalities in the corresponding system of the brain. During the last twenty years the functional magnetic resonance imaging (fMR1) technology has been instrumental in locating such abnormalities, identifying specific parts of the brain that, when dysfunctional, may enhance addiction and cause its positive or negative symptoms. This article reviews fMRI studies aimed toward locating areas in the brain that are responsible for cognitive, emotional, and motivational dysfunction. Cerebral correlatives of impulsiveness, behavior control, and drug cravings are reviewed separately. The article also contains an overview of possibilities to further investigate the Selves of those dependent on substances, identify previously unknown diagnostic markers of substance dependence, and evaluate the effectiveness of therapy. The research under review in this article provides data that points to a special role of the nucleus caudatus as well as the nucleus accumbens, the thalamus, the insular cortex (IC), the anterior cingulate, prefrontal and orbitofrontal areas in psychological disorders that are part of substance dependence. General findings of the article are in accordance with contemporary models of addictive pattern.

  14. Real-Time G-Protein-Coupled Receptor Imaging to Understand and Quantify Receptor Dynamics

    Directory of Open Access Journals (Sweden)

    María S. Aymerich

    2011-01-01

    Full Text Available Understanding the trafficking of G-protein-coupled receptors (GPCRs and their regulation by agonists and antagonists is fundamental to develop more effective drugs. Optical methods using fluorescent-tagged receptors and spinning disk confocal microscopy are useful tools to investigate membrane receptor dynamics in living cells. The aim of this study was to develop a method to characterize receptor dynamics using this system which offers the advantage of very fast image acquisition with minimal cell perturbation. However, in short-term assays photobleaching was still a problem. Thus, we developed a procedure to perform a photobleaching-corrected image analysis. A study of short-term dynamics of the long isoform of the dopamine type 2 receptor revealed an agonist-induced increase in the mobile fraction of receptors with a rate of movement of 0.08 μm/s For long-term assays, the ratio between the relative fluorescence intensity at the cell surface versus that in the intracellular compartment indicated that receptor internalization only occurred in cells co-expressing G protein-coupled receptor kinase 2. These results indicate that the lateral movement of receptors and receptor internalization are not directly coupled. Thus, we believe that live imaging of GPCRs using spinning disk confocal image analysis constitutes a powerful tool to study of receptor dynamics.

  15. Particle Image Velocimetry and Computational Fluid Dynamics Analysis of Fuel Cell Manifold

    DEFF Research Database (Denmark)

    Lebæk, Jesper; Blazniak Andreasen, Marcin; Andresen, Henrik Assenholm

    2010-01-01

    The inlet effect on the manifold flow in a fuel cell stack was investigated by means of numerical methods (computational fluid dynamics) and experimental methods (particle image velocimetry). At a simulated high current density situation the flow field was mapped on a 70 cell simulated cathode...

  16. Target acquisition performance : Effects of target aspect angle, dynamic imaging and signal processing

    NARCIS (Netherlands)

    Beintema, J.A.; Bijl, P.; Hogervorst, M.A.; Dijk, J.

    2008-01-01

    In an extensive Target Acquisition (TA) performance study, we recorded static and dynamic imagery of a set of military and civilian two-handheld objects at a range of distances and aspect angles with an under-sampled uncooled thermal imager. Next, we applied signal processing techniques including

  17. Model-based extraction of input and organ functions in dynamic scintigraphic imaging

    Czech Academy of Sciences Publication Activity Database

    Tichý, Ondřej; Šmídl, Václav; Šámal, M.

    2016-01-01

    Roč. 4, 3-4 (2016), s. 135-145 ISSN 2168-1171 R&D Projects: GA ČR GA13-29225S Institutional support: RVO:67985556 Keywords : blind source separation * convolution * dynamic medical imaging * compartment modelling Subject RIV: BB - Applied Statistics, Operational Research http://library.utia.cas.cz/separaty/2014/AS/tichy-0428540.pdf

  18. Identification of a Common Binding Mode for Imaging Agents to Amyloid Fibrils from Molecular Dynamics Simulations

    DEFF Research Database (Denmark)

    Skeby, Katrine Kirkeby; Sørensen, Jesper; Schiøtt, Birgit

    2013-01-01

    experimentally due to the insoluble nature of amyloid fibrils. This study uses molecular dynamics simulations to investigate the interactions between 13 aromatic amyloid imaging agents, entailing 4 different organic scaffolds, and a model of an amyloid fibril. Clustering analysis combined with free energy...

  19. An analysis of 99mTc-DTPA renal dynamic imaging in patients with diabetes mellitus

    International Nuclear Information System (INIS)

    Cao Guoxiang; Zhang Yongxue

    2000-01-01

    To investigate the regularity of renal dynamic imaging in the various courses of diabetes mellitus, and then to provide the important evidence variety for diagnosis and treatment. The data of renal dynamic imaging was analyzed on 276 kidneys of 40 normal and 98 diabetic patients, and according to course of disease, the diabetic patients was divided into three groups: ≤1 year, 1-5 year and ≥5 year respectively. Based upon was grouped 99m Tc-DTPA renal dynamic imaging and others, the renal functions into normal, approximately normal, I, II and III injury respectively, and the statistics and analysis of these data were carried out. The extent of renal function injury was related to the course of disease significantly, and it showed that the longer the course, the heavier the damage of renal function, and there was a significant difference between them (P 99m Tc-DTPA renal dynamic imaging can effectively evaluate the extent of renal functions injury and was also valuable for the clinical. Also, the study indicated that in diabetic patients susceptible to urinary tract infection could aggravate the injury of renal function

  20. Image-based rendering of intersecting surfaces for dynamic comparative visualization

    NARCIS (Netherlands)

    Busking, S.; Botha, C.P.; Ferrarini, L.; Milles, J.; Post, F.H.

    2010-01-01

    Nested or intersecting surfaces are proven techniques for visualizing shape differences between static 3D objects (Weigle and Taylor II, IEEE Visualization, Proceedings, pp. 503–510, 2005). In this paper we present an image-based formulation for these techniques that extends their use to dynamic

  1. Detecting abrupt dynamic change based on changes in the fractal properties of spatial images

    Science.gov (United States)

    Liu, Qunqun; He, Wenping; Gu, Bin; Jiang, Yundi

    2017-10-01

    Many abrupt climate change events often cannot be detected timely by conventional abrupt detection methods until a few years after these events have occurred. The reason for this lag in detection is that abundant and long-term observational data are required for accurate abrupt change detection by these methods, especially for the detection of a regime shift. So, these methods cannot help us understand and forecast the evolution of the climate system in a timely manner. Obviously, spatial images, generated by a coupled spatiotemporal dynamical model, contain more information about a dynamic system than a single time series, and we find that spatial images show the fractal properties. The fractal properties of spatial images can be quantitatively characterized by the Hurst exponent, which can be estimated by two-dimensional detrended fluctuation analysis (TD-DFA). Based on this, TD-DFA is used to detect an abrupt dynamic change of a coupled spatiotemporal model. The results show that the TD-DFA method can effectively detect abrupt parameter changes in the coupled model by monitoring the changing in the fractal properties of spatial images. The present method provides a new way for abrupt dynamic change detection, which can achieve timely and efficient abrupt change detection results.

  2. Tracking molecular dynamics without tracking: image correlation of photo-activation microscopy

    International Nuclear Information System (INIS)

    Pandžić, Elvis; Rossy, Jérémie; Gaus, Katharina

    2015-01-01

    Measuring protein dynamics in the plasma membrane can provide insights into the mechanisms of receptor signaling and other cellular functions. To quantify protein dynamics on the single molecule level over the entire cell surface, sophisticated approaches such as single particle tracking (SPT), photo-activation localization microscopy (PALM) and fluctuation-based analysis have been developed. However, analyzing molecular dynamics of fluorescent particles with intermittent excitation and low signal-to-noise ratio present at high densities has remained a challenge. We overcame this problem by applying spatio-temporal image correlation spectroscopy (STICS) analysis to photo-activated (PA) microscopy time series. In order to determine under which imaging conditions this approach is valid, we simulated PA images of diffusing particles in a homogeneous environment and varied photo-activation, reversible blinking and irreversible photo-bleaching rates. Further, we simulated data with high particle densities that populated mobile objects (such as adhesions and vesicles) that often interfere with STICS and fluctuation-based analysis. We demonstrated in experimental measurements that the diffusion coefficient of the epidermal growth factor receptor (EGFR) fused to PAGFP in live COS-7 cells can be determined in the plasma membrane and revealed differences in the time-dependent diffusion maps between wild-type and mutant Lck in activated T cells. In summary, we have developed a new analysis approach for live cell photo-activation microscopy data based on image correlation spectroscopy to quantify the spatio-temporal dynamics of single proteins. (paper)

  3. Tracking molecular dynamics without tracking: image correlation of photo-activation microscopy

    Science.gov (United States)

    Pandžić, Elvis; Rossy, Jérémie; Gaus, Katharina

    2015-03-01

    Measuring protein dynamics in the plasma membrane can provide insights into the mechanisms of receptor signaling and other cellular functions. To quantify protein dynamics on the single molecule level over the entire cell surface, sophisticated approaches such as single particle tracking (SPT), photo-activation localization microscopy (PALM) and fluctuation-based analysis have been developed. However, analyzing molecular dynamics of fluorescent particles with intermittent excitation and low signal-to-noise ratio present at high densities has remained a challenge. We overcame this problem by applying spatio-temporal image correlation spectroscopy (STICS) analysis to photo-activated (PA) microscopy time series. In order to determine under which imaging conditions this approach is valid, we simulated PA images of diffusing particles in a homogeneous environment and varied photo-activation, reversible blinking and irreversible photo-bleaching rates. Further, we simulated data with high particle densities that populated mobile objects (such as adhesions and vesicles) that often interfere with STICS and fluctuation-based analysis. We demonstrated in experimental measurements that the diffusion coefficient of the epidermal growth factor receptor (EGFR) fused to PAGFP in live COS-7 cells can be determined in the plasma membrane and revealed differences in the time-dependent diffusion maps between wild-type and mutant Lck in activated T cells. In summary, we have developed a new analysis approach for live cell photo-activation microscopy data based on image correlation spectroscopy to quantify the spatio-temporal dynamics of single proteins.

  4. Influence of different DEMs on the quality of the InSAR results: case study over Bankya and Mirovo areas

    Science.gov (United States)

    Nikolov, Hristo; Atanasova, Mila

    2017-10-01

    One of the key input parameters in obtaining end products from SAR data is the DEM used during their processing. This holds true especially when persistent scatterers InSAR method should be applied for example to study slow moving landslides or subsidence. Since nowadays most of the raw SAR data are of space borne origin for their correct processing to high precision products for relatively small areas with centimeter accuracy a DEM taking into account the particularities of the local topography is needed. Most of the DEMs used by the SAR processing software such as SRTM or ASTER are obtained by the same type of instrument and present some disagreements with height information acquired by leveling measurements or other geodetic means. This was the motivation for initiating this research - to prove the need of creating and using local DEM in SAR data processing at small scale and to check what the magnitude of the discrepancy between final InSAR products is in both cases where SRTM/ASTER and local DEM has been used. In addition investigated were two scenarios for SAR data processing - one with small baseline between image pairs and one having large baseline image pairs - in order to find out in which case local DEM has bigger impact. In course of this study two reference areas were considered - Bankya village near Sofia (SW region of Bulgaria) and Mirovo salt extraction site (NE region of Bulgaria). The reason those areas were selected lies in the high number of landslides registered and monitored by the competent authorities in the mentioned locations. The significance of the results obtained is witnessed by the fact that both sites we used have been included as reference sites for Bulgaria in the PanGeo EU funded project dealing with delivering information regarding ground instability geohazard as areas prone to subsidence of natural and manmade origin. In the said project largest part of the information has been extracted from Envisat SAR data, but now this

  5. Preliminary Study of Ground Movement in Prone Landslide Area by Means of MAI InSAR A Case Study: Ciloto, West Java, Indonesia

    Science.gov (United States)

    Hayati, Noorlaila; Riedel, Björn; Niemeier, Wolfgang

    2016-04-01

    Ciloto is one of the most prone landslide hazard areas in Indonesia. Several landslides in 2012 and 2013 had been recorded in Ciloto and damaged infrastructure around the area. Investigating the history of ground movement along slope area before the landslide happened could support the hazard mitigation in the future. Considering to an efficient surveying method, space-borne SAR processing is the one appropriate way to monitor the phenomenon in past years. The purpose of this study is detecting ground movement using multi-temporal synthetic aperture radar images. We use 13 ALOS PALSAR images from 2007 to 2009 with combination Fine Beam Single (FBS) and Fine Beam Double (FBD) polarization to investigate the slow movement on slope topography. MAI (Multiple Aperture Interferometry) InSAR method is used to analyze the ground movement from both line-of-sight and along-track direction. We split the synthetic aperture into two-looking aperture so that along-track displacement could be created by the difference of forward-backward looking interferograms. With integration of both methods, we could more precisely detect the movement in prone landslide area and achieve two measurements produced by the same interferogram. However, InSAR requires smaller baseline and good temporal baseline between master and slave images to avoid decorellation. There are only several pairs that meet the condition of proper length and temporal baseline indeed the location is also on the agriculture area where is mostly covered by vegetation. The result for two years observation shows that there is insignificant slow movement along slope surface in Ciloto with -2 - -7 cm in range looks or line of sight and 9-40 cm in along track direction. Based on geometry SAR , the most visible detecting of displacement is on the north-west area due to utilization of ascending SAR images.

  6. High-dynamic-range coherent diffractive imaging: ptychography using the mixed-mode pixel array detector

    Energy Technology Data Exchange (ETDEWEB)

    Giewekemeyer, Klaus, E-mail: klaus.giewekemeyer@xfel.eu [European XFEL GmbH, Hamburg (Germany); Philipp, Hugh T. [Cornell University, Ithaca, NY (United States); Wilke, Robin N. [Georg-August-Universität Göttingen, Göttingen (Germany); Aquila, Andrew [European XFEL GmbH, Hamburg (Germany); Osterhoff, Markus [Georg-August-Universität Göttingen, Göttingen (Germany); Tate, Mark W.; Shanks, Katherine S. [Cornell University, Ithaca, NY (United States); Zozulya, Alexey V. [Deutsches Elektronen-Synchrotron DESY, Hamburg (Germany); Salditt, Tim [Georg-August-Universität Göttingen, Göttingen (Germany); Gruner, Sol M. [Cornell University, Ithaca, NY (United States); Cornell University, Ithaca, NY (United States); Kavli Institute of Cornell for Nanoscience, Ithaca, NY (United States); Mancuso, Adrian P. [European XFEL GmbH, Hamburg (Germany)

    2014-08-07

    The advantages of a novel wide dynamic range hard X-ray detector are demonstrated for (ptychographic) coherent X-ray diffractive imaging. Coherent (X-ray) diffractive imaging (CDI) is an increasingly popular form of X-ray microscopy, mainly due to its potential to produce high-resolution images and the lack of an objective lens between the sample and its corresponding imaging detector. One challenge, however, is that very high dynamic range diffraction data must be collected to produce both quantitative and high-resolution images. In this work, hard X-ray ptychographic coherent diffractive imaging has been performed at the P10 beamline of the PETRA III synchrotron to demonstrate the potential of a very wide dynamic range imaging X-ray detector (the Mixed-Mode Pixel Array Detector, or MM-PAD). The detector is capable of single photon detection, detecting fluxes exceeding 1 × 10{sup 8} 8-keV photons pixel{sup −1} s{sup −1}, and framing at 1 kHz. A ptychographic reconstruction was performed using a peak focal intensity on the order of 1 × 10{sup 10} photons µm{sup −2} s{sup −1} within an area of approximately 325 nm × 603 nm. This was done without need of a beam stop and with a very modest attenuation, while ‘still’ images of the empty beam far-field intensity were recorded without any attenuation. The treatment of the detector frames and CDI methodology for reconstruction of non-sensitive detector regions, partially also extending the active detector area, are described.

  7. Ectopic posterior pituitary high signal in preoperative and postoperative macroadenomas: dynamic MR imaging

    International Nuclear Information System (INIS)

    Takahashi, Takahiro; Miki, Yukio; Takahashi, Jun A.; Kanagaki, Mitsunori; Yamamoto, Akira; Fushimi, Yasutaka; Okada, Tsutomu; Haque, Tabassum Laz; Hashimoto, Nobuo; Konishi, Junji; Togashi, Kaori

    2005-01-01

    Background and purpose: In patients with macroadenoma, posterior pituitary high signal (PPHS) on T1-weighted magnetic resonance (MR) imaging is sometimes observed in an ectopic location. The present study compared incidences of ectopic PPHS before and after macroadenoma surgery using MR imaging, including dynamic MR imaging to ascertain whether this ectopic change is irreversible. Materials and methods: MR imaging was performed preoperatively in 111 cases of macroadenoma, and then repeated more than 1-year postoperatively in 47 patients. Enhancement of PPHS was assessed using dynamic MR imaging. Areas of enhanced hyperintensity were considered true PPHS, and the relationship between presence and location of true PPHS and adenoma volume was analyzed. Moreover, changes in the presence and location of true PPHS were ascertained among the patients who underwent postoperative follow-up MR imaging. Results: Preoperatively, PPHS was seen only in the normal location in 29 patients (Group A: 26.1%). High signal was detected only in an ectopic location in 58 patients, and early enhancement of this ectopic high signal was confirmed by dynamic MR imaging in 56 patients (Group B: 50.5%). No PPHS was observed in 24 patients (Group C: 21.6%). Adenoma volume was significantly greater for Group B than for Group A (p < 0.001). Among the Group B patients who underwent MR imaging postoperatively (n = 31), the location of PPHS was not changed, except for two patients in whom PPHS was absent. Postoperatively, PPHS was not observed in the normal location in any patient in the Group B. Conclusions: Greater volume of adenoma is associated with a higher incidence of ectopic PPHS, and the ectopic change is irreversible

  8. L band InSAR sudy on the Ganos section of the North Anatolian Fault Zone (NAFZ)

    Science.gov (United States)

    de Michele, Marcello

    2016-04-01

    The North Anatolian Fault (NAF), with a total length of about 1500 km, is one of the most active right-lateral strike-slip faults in the world. It defines the tectonic boundary between the Anatolian Plate and the Eurasian Plate in northern Turkey, accommodating ~14-30 mm/yr of relative plate motion between the two plates (fig. 1). The Gazikoy-Saros segment (the Ganos fault, GF) is the onshore segment of the northern strand of the NAF between the Marmara Sea and the Gulf of Saros. It was last ruptured in 1912 with a Ms=7.4 earthquake that broke the entire inland segment of the fault, a length of about 50 km, and produced a right-lateral strike-slip component of at least 3 m. Other large historical earthquakes that have been attributed to the Ganos fault occurred in A.D. 824, 1343, 1509 and 1766 (e. g. Reilinger et al., 2000; Meade et al., 2002; Motagh et al., 2007; Janssen et al., 2009; Megraoui et al., 2012 ; Ersen Aksoy et al., 2010). The GF forms a 45 km long linear fault system and represents the link between the northern strand of the NAFZ in the Sea of Marmara and the North Aegean Trough where slip partitioning results in branching of the fault zone. The present study aims at showing the results retrieved from L band Interferometric Syntethic Aperture Radar (InSAR) measurements for the monitoring of Crustal Deformation in the Anatolian Fault Zone in the frame of the MARMARA SUPERSITE PROJECT "MARSITE" on the Ganos section of the North Anatolian fault zone. We processed SAR data made available through the CAT-1 ESA (European Space Agency) archives, acquired by the L-band radar sensor ALOS PALSAR between 2007 and 2011. The aim of this exercise is to test L-band capabilities to map the spatial and temporal evolution of the present-day crustal deformation phenomena affecting the Ganos section of the NAFZ with high level of spatial details. The goal of this task is to assess whether InSAR L-Band data can be useful to evaluate the long-term behavior of active faults

  9. A real-time dynamic imaging system for centrifugal microflow platforms

    International Nuclear Information System (INIS)

    Chang, Hsing-Cheng; Tsou, Chingfu; Lai, Chi-Chih; Wun, Guo-Hong

    2008-01-01

    Based on the operational concept of quasi-static state and optoelectronic measurement technology, this research develops a real-time dynamic imaging system for centrifugal microfluidic platforms. Unlike the conventional centrifugal inspection system, which can only be used for examination of the final steady stage in microflow analysis, the developed system with a multi-speed controller and object tracking design is fabricated with low cost to recognize dynamic microflow patterns for different kinds of compact disc-type centrifugal microstructures. The characteristics of rotational control efficiency and image acquisition quality are obtained from fluidic microvalve experiments that are achieved in measuring microflow dynamic responses and in visualizing transient microflow patterns. A man–machine interface was connected with a computer to perform the control and alignment adjustments to catch exact image data for following analysis. The rotation stability of the system has been evaluated, and the rotation speed up to 4500 rpm with vertical vibration less than ±0.2 mm is achieved measured at radial distance of 5 cm. The image acquisition is transferred via USB 2.0 at a speed of up to 30 images per second to the display and memory module

  10. Image-Based Reconstruction and Analysis of Dynamic Scenes in a Landslide Simulation Facility

    Science.gov (United States)

    Scaioni, M.; Crippa, J.; Longoni, L.; Papini, M.; Zanzi, L.

    2017-12-01

    The application of image processing and photogrammetric techniques to dynamic reconstruction of landslide simulations in a scaled-down facility is described. Simulations are also used here for active-learning purpose: students are helped understand how physical processes happen and which kinds of observations may be obtained from a sensor network. In particular, the use of digital images to obtain multi-temporal information is presented. On one side, using a multi-view sensor set up based on four synchronized GoPro 4 Black® cameras, a 4D (3D spatial position and time) reconstruction of the dynamic scene is obtained through the composition of several 3D models obtained from dense image matching. The final textured 4D model allows one to revisit in dynamic and interactive mode a completed experiment at any time. On the other side, a digital image correlation (DIC) technique has been used to track surface point displacements from the image sequence obtained from the camera in front of the simulation facility. While the 4D model may provide a qualitative description and documentation of the experiment running, DIC analysis output quantitative information such as local point displacements and velocities, to be related to physical processes and to other observations. All the hardware and software equipment adopted for the photogrammetric reconstruction has been based on low-cost and open-source solutions.

  11. IMAGE-BASED RECONSTRUCTION AND ANALYSIS OF DYNAMIC SCENES IN A LANDSLIDE SIMULATION FACILITY

    Directory of Open Access Journals (Sweden)

    M. Scaioni

    2017-12-01

    Full Text Available The application of image processing and photogrammetric techniques to dynamic reconstruction of landslide simulations in a scaled-down facility is described. Simulations are also used here for active-learning purpose: students are helped understand how physical processes happen and which kinds of observations may be obtained from a sensor network. In particular, the use of digital images to obtain multi-temporal information is presented. On one side, using a multi-view sensor set up based on four synchronized GoPro 4 Black® cameras, a 4D (3D spatial position and time reconstruction of the dynamic scene is obtained through the composition of several 3D models obtained from dense image matching. The final textured 4D model allows one to revisit in dynamic and interactive mode a completed experiment at any time. On the other side, a digital image correlation (DIC technique has been used to track surface point displacements from the image sequence obtained from the camera in front of the simulation facility. While the 4D model may provide a qualitative description and documentation of the experiment running, DIC analysis output quantitative information such as local point displacements and velocities, to be related to physical processes and to other observations. All the hardware and software equipment adopted for the photogrammetric reconstruction has been based on low-cost and open-source solutions.

  12. Live cell CRISPR-imaging in plants reveals dynamic telomere movements

    KAUST Repository

    Dreissig, Steven

    2017-05-16

    Elucidating the spatio-temporal organization of the genome inside the nucleus is imperative to understand the regulation of genes and non-coding sequences during development and environmental changes. Emerging techniques of chromatin imaging promise to bridge the long-standing gap between sequencing studies which reveal genomic information and imaging studies that provide spatial and temporal information of defined genomic regions. Here, we demonstrate such an imaging technique based on two orthologues of the bacterial CRISPR-Cas9 system. By fusing eGFP/mRuby2 to the catalytically inactive version of Streptococcus pyogenes and Staphylococcus aureus Cas9, we show robust visualization of telomere repeats in live leaf cells of Nicotiana benthamiana. By tracking the dynamics of telomeres visualized by CRISPR-dCas9, we reveal dynamic telomere movements of up to 2 μm within 30 minutes during interphase. Furthermore, we show that CRISPR-dCas9 can be combined with fluorescence-labelled proteins to visualize DNA-protein interactions in vivo. By simultaneously using two dCas9 orthologues, we pave the way for imaging of multiple genomic loci in live plants cells. CRISPR-imaging bears the potential to significantly improve our understanding of the dynamics of chromosomes in live plant cells.

  13. Detailed analysis of latencies in image-based dynamic MLC tracking

    International Nuclear Information System (INIS)

    Poulsen, Per Rugaard; Cho, Byungchul; Sawant, Amit; Ruan, Dan; Keall, Paul J.

    2010-01-01

    Purpose: Previous measurements of the accuracy of image-based real-time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image-based DMLC tracking. Methods: A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three-dimensional target position by a single-imager method and adjusted the MLC aperture to the target position. Imaging intervals ΔT image from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files. Results: For ΔT image =150 ms, the total time from image acquisition to completed MLC adjustment was 380±9 ms for MV and 420±12 ms for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms), MLC position

  14. Detailed analysis of latencies in image-based dynamic MLC tracking

    Energy Technology Data Exchange (ETDEWEB)

    Poulsen, Per Rugaard; Cho, Byungchul; Sawant, Amit; Ruan, Dan; Keall, Paul J. [Department of Radiation Oncology, Stanford University, Stanford, California 94305 and Department of Oncology and Department of Medical Physics, Aarhus University Hospital, 8000 Aarhus (Denmark); Department of Radiation Oncology, Stanford University, Stanford, California 94305 and Department of Radiation Oncology, Asan Medical Center, Seoul 138-736 (Korea, Republic of); Department of Radiation Oncology, Stanford University, Stanford, California 94305 (United States)

    2010-09-15

    Purpose: Previous measurements of the accuracy of image-based real-time dynamic multileaf collimator (DMLC) tracking show that the major contributor to errors is latency, i.e., the delay between target motion and MLC response. Therefore the purpose of this work was to develop a method for detailed analysis of latency contributions during image-based DMLC tracking. Methods: A prototype DMLC tracking system integrated with a linear accelerator was used for tracking a phantom with an embedded fiducial marker during treatment delivery. The phantom performed a sinusoidal motion. Real-time target localization was based on x-ray images acquired either with a portal imager or a kV imager mounted orthogonal to the treatment beam. Each image was stored in a file on the imaging workstation. A marker segmentation program opened the image file, determined the marker position in the image, and transferred it to the DMLC tracking program. This program estimated the three-dimensional target position by a single-imager method and adjusted the MLC aperture to the target position. Imaging intervals {Delta}T{sub image} from 150 to 1000 ms were investigated for both kV and MV imaging. After the experiments, the recorded images were synchronized with MLC log files generated by the MLC controller and tracking log files generated by the tracking program. This synchronization allowed temporal analysis of the information flow for each individual image from acquisition to completed MLC adjustment. The synchronization also allowed investigation of the MLC adjustment dynamics on a considerably finer time scale than the 50 ms time resolution of the MLC log files. Results: For {Delta}T{sub image}=150 ms, the total time from image acquisition to completed MLC adjustment was 380{+-}9 ms for MV and 420{+-}12 ms for kV images. The main part of this time was from image acquisition to completed image file writing (272 ms for MV and 309 ms for kV). Image file opening (38 ms), marker segmentation (4 ms

  15. Dynamic autofocus for continuous-scanning time-delay-and-integration image acquisition in automated microscopy.

    Science.gov (United States)

    Bravo-Zanoguera, Miguel E; Laris, Casey A; Nguyen, Lam K; Oliva, Mike; Price, Jeffrey H

    2007-01-01

    Efficient image cytometry of a conventional microscope slide means rapid acquisition and analysis of 20 gigapixels of image data (at 0.3-microm sampling). The voluminous data motivate increased acquisition speed to enable many biomedical applications. Continuous-motion time-delay-and-integrate (TDI) scanning has the potential to speed image acquisition while retaining sensitivity, but the challenge of implementing high-resolution autofocus operating simultaneously with acquisition has limited its adoption. We develop a dynamic autofocus system for this need using: 1. a "volume camera," consisting of nine fiber optic imaging conduits to charge-coupled device (CCD) sensors, that acquires images in parallel from different focal planes, 2. an array of mixed analog-digital processing circuits that measure the high spatial frequencies of the multiple image streams to create focus indices, and 3. a software system that reads and analyzes the focus data streams and calculates best focus for closed feedback loop control. Our system updates autofocus at 56 Hz (or once every 21 microm of stage travel) to collect sharply focused images sampled at 0.3x0.3 microm(2)/pixel at a stage speed of 2.3 mms. The system, tested by focusing in phase contrast and imaging long fluorescence strips, achieves high-performance closed-loop image-content-based autofocus in continuous scanning for the first time.

  16. Endocardium and Epicardium Segmentation in MR Images Based on Developed Otsu and Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Shengzhou XU

    2014-03-01

    Full Text Available In order to accurately extract the endocardium and epicardium of the left ventricle from cardiac magnetic resonance (MR images, a method based on developed Otsu and dynamic programming has been proposed. First, regions with high gray value are divided into several left ventricle candidate regions by the developed Otsu algorithm, which based on constraining the search range of the ideal segmentation threshold. Then, left ventricular blood pool is selected from the candidate regions and its convex hull is found out as the endocardium. The epicardium is derived by applying dynamic programming method to find a closed path with minimum local cost. The local cost function of the dynamic programming method consists of two factors: boundary gradient and shape features. In order to improve the accuracy of segmentation, a non-maxima gradient suppression technique is adopted to get the boundary gradient. The experimental result of 138 MR images show that the method proposed has high accuracy and robustness.

  17. Automatic extraction of myocardial mass and volumes using parametric images from dynamic nongated PET

    DEFF Research Database (Denmark)

    Harms, Hendrik Johannes; Hansson, Nils Henrik Stubkjær; Tolbod, Lars Poulsen

    2016-01-01

    Dynamic cardiac positron emission tomography (PET) is used to quantify molecular processes in vivo. However, measurements of left-ventricular (LV) mass and volumes require electrocardiogram (ECG)-gated PET data. The aim of this study was to explore the feasibility of measuring LV geometry using non......-gated dynamic cardiac PET. METHODS: Thirty-five patients with aortic-valve stenosis and 10 healthy controls (HC) underwent a 27-min 11C-acetate PET/CT scan and cardiac magnetic resonance imaging (CMR). HC were scanned twice to assess repeatability. Parametric images of uptake rate K1 and the blood pool were......LV and WT only and an overestimation for LVEF at lower values. Intra- and inter-observer correlations were >0.95 for all PET measurements. PET repeatability accuracy in HC was comparable to CMR. CONCLUSION: LV mass and volumes are accurately and automatically generated from dynamic 11C-acetate PET without...

  18. ERT, GPR, InSAR, and tracer tests to characterize karst aquifer systems under urban areas: The case of Quebec City

    Science.gov (United States)

    Martel, Richard; Castellazzi, Pascal; Gloaguen, Erwan; Trépanier, Luc; Garfias, Jaime

    2018-06-01

    Urban infrastructures built over karst settings may be at risk of collapse due to hydro-chemical erosion of underlying rock structures. In such settings, mapping cave networks and monitoring ground stability is important to assure civil safety and guide future infrastructure development decisions. However, no technique can directly and comprehensively map these hydrogeological features and monitor their stability. The most reliable method to map a cave network is through speleological exploration, which is not always possible due to restrictions, narrow corridors/passages, or high water levels. Borehole drilling is expensive and is often only performed where the presence of karsts is suggested by other techniques. Numerous indirect and cost-effective methods exist to map a karst flow system, such as geophysics, geodesy, and tracer tests. This paper presents the outcomes from a challenging application in Quebec City, Canada, where a multidisciplinary approach was designed to better understand the groundwater dynamics and cave paths. Two tracer tests in groundwater flowing through the cave system indicated that water flows along an approximately straight path from the sinking stream to the spring. It also suggests the presence of a parallel flow path close to the one already partially mapped. This observation was confirmed by combining Ground Penetrating Radar (GPR) and Electrical Resistivity Tomography (ERT) techniques, and ultimately by observing voids in several boreholes drilled close to the main cave path. Lowering the water levels at the suspected infiltration zone and inside the karst, the infiltration cracks were identified and the hydraulic link between them was confirmed. In fact, almost no infiltration occurs into the karst system when the water level at the sinking stream drops below a threshold level. Finally, SAR interferometry (InSAR) using RADARSAT-2 images detected movements on few buildings located over a backfilled sinkhole intercepted by the karst

  19. Leaf trajectory verification during dynamic intensity modulated radiotherapy using an amorphous silicon flat panel imager

    International Nuclear Information System (INIS)

    Sonke, Jan-Jakob; Ploeger, Lennert S.; Brand, Bob; Smitsmans, Monique H.P.; Herk, Marcel van

    2004-01-01

    An independent verification of the leaf trajectories during each treatment fraction improves the safety of IMRT delivery. In order to verify dynamic IMRT with an electronic portal imaging device (EPID), the EPID response should be accurate and fast such that the effect of motion blurring on the detected moving field edge position is limited. In the past, it was shown that the errors in the detected position of a moving field edge determined by a scanning liquid-filled ionization chamber (SLIC) EPID are negligible in clinical practice. Furthermore, a method for leaf trajectory verification during dynamic IMRT was successfully applied using such an EPID. EPIDs based on amorphous silicon (a-Si) arrays are now widely available. Such a-Si flat panel imagers (FPIs) produce portal images with superior image quality compared to other portal imaging systems, but they have not yet been used for leaf trajectory verification during dynamic IMRT. The aim of this study is to quantify the effect of motion distortion and motion blurring on the detection accuracy of a moving field edge for an Elekta iViewGT a-Si FPI and to investigate its applicability for the leaf trajectory verification during dynamic IMRT. We found that the detection error for a moving field edge to be smaller than 0.025 cm at a speed of 0.8 cm/s. Hence, the effect of motion blurring on the detection accuracy of a moving field edge is negligible in clinical practice. Furthermore, the a-Si FPI was successfully applied for the verification of dynamic IMRT. The verification method revealed a delay in the control system of the experimental DMLC that was also found using a SLIC EPID, resulting in leaf positional errors of 0.7 cm at a leaf speed of 0.8 cm/s

  20. Contrast-enhanced magnetic resonance imaging of the breast: the value of pharmacokinetic parameters derived from fast dynamic imaging during initial enhancement in classifying lesions

    International Nuclear Information System (INIS)

    Veltman, J.; Stoutjesdijk, M.; Mann, R.; Huisman, H.J.; Barentsz, J.O.; Blickman, J.G.; Boetes, C.

    2008-01-01

    The value of pharmacokinetic parameters derived from fast dynamic imaging during initial enhancement in characterizing breast lesions on magnetic resonance imaging (MRI) was evaluated. Sixty-eight malignant and 34 benign lesions were included. In the scanning protocol, high temporal resolution imaging was combined with high spatial resolution imaging. The high temporal resolution images were recorded every 4.1 s during initial enhancement (fast dynamic analysis). The high spatial resolution images were recorded at a temporal resolution of 86 s (slow dynamic analysis). In the fast dynamic evaluation pharmacokinetic parameters (K trans , V e and k ep ) were evaluated. In the slow dynamic analysis, each lesion was scored according to the BI-RADS classification. Two readers evaluated all data prospectively. ROC and multivariate analysis were performed. The slow dynamic analysis resulted in an AUC of 0.85 and 0.83, respectively. The fast dynamic analysis resulted in an AUC of 0.83 in both readers. The combination of both the slow and fast dynamic analyses resulted in a significant improvement of diagnostic performance with an AUC of 0.93 and 0.90 (P = 0.02). The increased diagnostic performance found when combining both methods demonstrates the additional value of our method in further improving the diagnostic performance of breast MRI. (orig.)

  1. Investigating Atmospheric Oxidation with Molecular Dynamics Imaging and Spectroscopy

    Science.gov (United States)

    Merrill, W. G.; Case, A. S.; Keutsch, F. N.

    2013-06-01

    Volatile organic compounds (VOCs) in the Earth's atmosphere constitute trace gas species emitted primarily from the biosphere, and are the subject of inquiry for a variety of air quality and climate studies. Reactions intiated (primarily) by the hydroxyl radical (OH) lead to a myriad of oxygenated species (OVOCs), which in turn are prone to further oxidation. Investigations of the role that VOC oxidation plays in tropospheric chemistry have brought to light two troubling scenarios: (1) VOCs are responsible in part for the production of two EPA-regulated pollutants---tropospheric ozone and organic aerosol---and (2) the mechanistic details of VOC oxidation remain convoluted and poorly understood. The latter issue hampers the implementation of near-explicit atmospheric simulations, and large discrepancies in OH reactivity exist between measurements and models at present. Such discrepancies underscore the need for a more thorough description of VOC oxidation. Time-of-flight measurements and ion-imaging techniques are viable options for resolving some of the mechanistic and energetic details of VOC oxidation. Molecular beam studies have the advantage of foregoing unwanted bimolecular reactions, allowing for the characterization of specific processes which must typically compete with the complex manifold of VOC oxidation pathways. The focus of this work is on the unimolecular channels of organic peroxy radical intermediates, which are necessarily generated during VOC oxidation. Such intermediates may isomerize and decompose into distinct chemical channels, enabling the unambiguous detection of each pathway. For instance, a (1 + 1') resonance enhanced multiphoton ionization (REMPI) scheme may be employed to detect carbon monoxide generated from a particular unimolecular process. A number of more subtle mechanistic details may be explored as well. By varying the mean free path of the peroxy radicals in a flow tube, the role of collisional quenching in these unimolecular

  2. High Dynamic Range Imaging at the Quantum Limit with Single Photon Avalanche Diode-Based Image Sensors †

    Science.gov (United States)

    Mattioli Della Rocca, Francescopaolo

    2018-01-01

    This paper examines methods to best exploit the High Dynamic Range (HDR) of the single photon avalanche diode (SPAD) in a high fill-factor HDR photon counting pixel that is scalable to megapixel arrays. The proposed method combines multi-exposure HDR with temporal oversampling in-pixel. We present a silicon demonstration IC with 96 × 40 array of 8.25 µm pitch 66% fill-factor SPAD-based pixels achieving >100 dB dynamic range with 3 back-to-back exposures (short, mid, long). Each pixel sums 15 bit-planes or binary field images internally to constitute one frame providing 3.75× data compression, hence the 1k frames per second (FPS) output off-chip represents 45,000 individual field images per second on chip. Two future projections of this work are described: scaling SPAD-based image sensors to HDR 1 MPixel formats and shrinking the pixel pitch to 1–3 µm. PMID:29641479

  3. The TRICLOBS Dynamic Multi-Band Image Data Set for the Development and Evaluation of Image Fusion Methods.

    Directory of Open Access Journals (Sweden)

    Alexander Toet

    Full Text Available The fusion and enhancement of multiband nighttime imagery for surveillance and navigation has been the subject of extensive research for over two decades. Despite the ongoing efforts in this area there is still only a small number of static multiband test images available for the development and evaluation of new image fusion and enhancement methods. Moreover, dynamic multiband imagery is also currently lacking. To fill this gap we present the TRICLOBS dynamic multi-band image data set containing sixteen registered visual (0.4-0.7μm, near-infrared (NIR, 0.7-1.0μm and long-wave infrared (LWIR, 8-14μm motion sequences. They represent different military and civilian surveillance scenarios registered in three different scenes. Scenes include (military and civilian people that are stationary, walking or running, or carrying various objects. Vehicles, foliage, and buildings or other man-made structures are also included in the scenes. This data set is primarily intended for the development and evaluation of image fusion, enhancement and color mapping algorithms for short-range surveillance applications. The imagery was collected during several field trials with our newly developed TRICLOBS (TRI-band Color Low-light OBServation all-day all-weather surveillance system. This system registers a scene in the Visual, NIR and LWIR part of the electromagnetic spectrum using three optically aligned sensors (two digital image intensifiers and an uncooled long-wave infrared microbolometer. The three sensor signals are mapped to three individual RGB color channels, digitized, and stored as uncompressed RGB (false color frames. The TRICLOBS data set enables the development and evaluation of (both static and dynamic image fusion, enhancement and color mapping algorithms. To allow the development of realistic color remapping procedures, the data set also contains color photographs of each of the three scenes. The color statistics derived from these photographs

  4. Time series modeling of live-cell shape dynamics for image-based phenotypic profiling.

    Science.gov (United States)

    Gordonov, Simon; Hwang, Mun Kyung; Wells, Alan; Gertler, Frank B; Lauffenburger, Douglas A; Bathe, Mark

    2016-01-01

    Live-cell imaging can be used to capture spatio-temporal aspects of cellular responses that are not accessible to fixed-cell imaging. As the use of live-cell imaging continues to increase, new computational procedures are needed to characterize and classify the temporal dynamics of individual cells. For this purpose, here we present the general experimental-computational framework SAPHIRE (Stochastic Annotation of Phenotypic Individual-cell Responses) to characterize phenotypic cellular responses from time series imaging datasets. Hidden Markov modeling is used to infer and annotate morphological state and state-switching properties from image-derived cell shape measurements. Time series modeling is performed on each cell individually, making the approach broadly useful for analyzing asynchronous cell populations. Two-color fluorescent cells simultaneously expressing actin and nuclear reporters enabled us to profile temporal changes in cell shape following pharmacological inhibition of cytoskeleton-regulatory signaling pathways. Results are compared with existing approaches conventionally applied to fixed-cell imaging datasets, and indicate that time series modeling captures heterogeneous dynamic cellular responses that can improve drug classification and offer additional important insight into mechanisms of drug action. The software is available at http://saphire-hcs.org.

  5. An improved method to estimate reflectance parameters for high dynamic range imaging

    Science.gov (United States)

    Li, Shiying; Deguchi, Koichiro; Li, Renfa; Manabe, Yoshitsugu; Chihara, Kunihiro

    2008-01-01

    Two methods are described to accurately estimate diffuse and specular reflectance parameters for colors, gloss intensity and surface roughness, over the dynamic range of the camera used to capture input images. Neither method needs to segment color areas on an image, or to reconstruct a high dynamic range (HDR) image. The second method improves on the first, bypassing the requirement for specific separation of diffuse and specular reflection components. For the latter method, diffuse and specular reflectance parameters are estimated separately, using the least squares method. Reflection values are initially assumed to be diffuse-only reflection components, and are subjected to the least squares method to estimate diffuse reflectance parameters. Specular reflection components, obtained by subtracting the computed diffuse reflection components from reflection values, are then subjected to a logarithmically transformed equation of the Torrance-Sparrow reflection model, and specular reflectance parameters for gloss intensity and surface roughness are finally estimated using the least squares method. Experiments were carried out using both methods, with simulation data at different saturation levels, generated according to the Lambert and Torrance-Sparrow reflection models, and the second method, with spectral images captured by an imaging spectrograph and a moving light source. Our results show that the second method can estimate the diffuse and specular reflectance parameters for colors, gloss intensity and surface roughness more accurately and faster than the first one, so that colors and gloss can be reproduced more efficiently for HDR imaging.

  6. Estimation of physiological parameters using knowledge-based factor analysis of dynamic nuclear medicine image sequences

    International Nuclear Information System (INIS)

    Yap, J.T.; Chen, C.T.; Cooper, M.

    1995-01-01

    The authors have previously developed a knowledge-based method of factor analysis to analyze dynamic nuclear medicine image sequences. In this paper, the authors analyze dynamic PET cerebral glucose metabolism and neuroreceptor binding studies. These methods have shown the ability to reduce the dimensionality of the data, enhance the image quality of the sequence, and generate meaningful functional images and their corresponding physiological time functions. The new information produced by the factor analysis has now been used to improve the estimation of various physiological parameters. A principal component analysis (PCA) is first performed to identify statistically significant temporal variations and remove the uncorrelated variations (noise) due to Poisson counting statistics. The statistically significant principal components are then used to reconstruct a noise-reduced image sequence as well as provide an initial solution for the factor analysis. Prior knowledge such as the compartmental models or the requirement of positivity and simple structure can be used to constrain the analysis. These constraints are used to rotate the factors to the most physically and physiologically realistic solution. The final result is a small number of time functions (factors) representing the underlying physiological processes and their associated weighting images representing the spatial localization of these functions. Estimation of physiological parameters can then be performed using the noise-reduced image sequence generated from the statistically significant PCs and/or the final factor images and time functions. These results are compared to the parameter estimation using standard methods and the original raw image sequences. Graphical analysis was performed at the pixel level to generate comparable parametric images of the slope and intercept (influx constant and distribution volume)

  7. Phase correction and error estimation in InSAR time series analysis

    Science.gov (United States)

    Zhang, Y.; Fattahi, H.; Amelung, F.

    2017-12-01

    During the last decade several InSAR time series approaches have been developed in response to the non-idea acquisition strategy of SAR satellites, such as large spatial and temporal baseline with non-regular acquisitions. The small baseline tubes and regular acquisitions of new SAR satellites such as Sentinel-1 allows us to form fully connected networks of interferograms and simplifies the time series analysis into a weighted least square inversion of an over-determined system. Such robust inversion allows us to focus more on the understanding of different components in InSAR time-series and its uncertainties. We present an open-source python-based package for InSAR time series analysis, called PySAR (https://yunjunz.github.io/PySAR/), with unique functionalities for obtaining unbiased ground displacement time-series, geometrical and atmospheric correction of InSAR data and quantifying the InSAR uncertainty. Our implemented strategy contains several features including: 1) improved spatial coverage using coherence-based network of interferograms, 2) unwrapping error correction using phase closure or bridging, 3) tropospheric delay correction using weather models and empirical approaches, 4) DEM error correction, 5) optimal selection of reference date and automatic outlier detection, 6) InSAR uncertainty due to the residual tropospheric delay, decorrelation and residual DEM error, and 7) variance-covariance matrix of final products for geodetic inversion. We demonstrate the performance using SAR datasets acquired by Cosmo-Skymed and TerraSAR-X, Sentinel-1 and ALOS/ALOS-2, with application on the highly non-linear volcanic deformation in Japan and Ecuador (figure 1). Our result shows precursory deformation before the 2015 eruptions of Cotopaxi volcano, with a maximum uplift of 3.4 cm on the western flank (fig. 1b), with a standard deviation of 0.9 cm (fig. 1a), supporting the finding by Morales-Rivera et al. (2017, GRL); and a post-eruptive subsidence on the same

  8. Episodic inflation of Akutan volcano, Alaska revealed from GPS and InSAR time series

    Science.gov (United States)

    DeGrandpre, K.; Lu, Z.; Wang, T.

    2016-12-01

    Akutan volcano is one of the most active volcanoes located long the Aleutian arc. At least 27 eruptions have been noted since 1790 and an intense swarm of volcano-tectonic earthquakes occurred in 1996. Surface deformation after the 1996 earthquake sequence has been studied using GPS and Interferometric Synthetic Aperture Radar (InSAR) separately, yet models created from these datasets require different mechanisms to produce the observed surface deformation: an inflating Mogi source results in the best approximation of displacement observed from GPS data, whereas an opening dyke is the best fit to deformation measured from InSAR. A recent study using seismic data revealed complex magmatic structures beneath the caldera, suggesting that the surface deformation may reflect more complicated mechanisms that cannot be estimated using one type of data alone. Here we integrate the surface deformation measured from GPS and InSAR to better understand the magma plumbing system beneath Akutan volcano. GPS time-series at 12 stations from 2006 to 2016 were analyzed, and two transient episodes of inflation in 2008 and 2014 were detected. These GPS stations are, however, too sparse to reveal the spatial distribution of the surface deformation. In order to better define the spatial extent of this inflation four tracks of Envisat data acquired during 2003-2010 and one track of TerraSAR-X data acquired from 2010 to 2016 were processed to produce high-resolution maps of surface deformation. These deformation maps show a consistently uplifting area on the northwestern flank of the volcano. We inverted for the source parameters required to produce the inflation using GPS, InSAR, and a dataset of GPS and InSAR measurements combined, to find that a deep Mogi source below a shallow dyke fit these datasets best. From the TerraSAR-X data, we were also able to measure the subsidence inside the summit caldera due to fumarole activity to be as high as 10 mm/yr. The complex spatial and temporal

  9. Toward regional corrections of long period CMT inversions using InSAR

    Science.gov (United States)

    Shakibay Senobari, N.; Funning, G.; Ferreira, A. M.

    2017-12-01

    One of InSAR's main strengths, with respect to other methods of studying earthquakes, is finding the accurate location of the best point source (or `centroid') for an earthquake. While InSAR data have great advantages for study of shallow earthquakes, the number of earthquakes for which we have InSAR data is low, compared with the number of earthquakes recorded seismically. And though improvements to SAR satellite constellations have enhanced the use of InSAR data during earthquake response, post-event data still have a latency on the order of days. On the other hand, earthquake centroid inversion methods using long period seismic data (e.g. the Global CMT method) are fast but include errors caused by inaccuracies in both the Earth velocity model and in wave propagation assumptions (e.g. Hjörleifsdóttir and Ekström, 2010; Ferreira and Woodhouse, 2006). Here we demonstrate a method that combines the strengths of both methods, calculating regional travel-time corrections for long-period waveforms using accurate centroid locations from InSAR, then applying these to other events that occur in the same region. Our method is based on the observation that synthetic seismograms produced from InSAR source models and locations match the data very well except for some phase shifts (travel time biases) between the two waveforms, likely corresponding to inaccuracies in Earth velocity models (Weston et al., 2014). Our previous work shows that adding such phase shifts to the Green's functions can improve the accuracy of long period seismic CMT inversions by reducing tradeoffs between the moment tensor components and centroid location (e.g. Shakibay Senobari et al., AGU Fall Meeting 2015). Preliminary work on several pairs of neighboring events (e.g. Landers-Hector Mine, the 2000 South Iceland earthquake sequences) shows consistent azimuthal patterns of these phase shifts for nearby events at common stations. These phase shift patterns strongly suggest that it is possible to

  10. High throughput static and dynamic small animal imaging using clinical PET/CT: potential preclinical applications

    International Nuclear Information System (INIS)

    Aide, Nicolas; Desmonts, Cedric; Agostini, Denis; Bardet, Stephane; Bouvard, Gerard; Beauregard, Jean-Mathieu; Roselt, Peter; Neels, Oliver; Beyer, Thomas; Kinross, Kathryn; Hicks, Rodney J.

    2010-01-01

    The objective of the study was to evaluate state-of-the-art clinical PET/CT technology in performing static and dynamic imaging of several mice simultaneously. A mouse-sized phantom was imaged mimicking simultaneous imaging of three mice with computation of recovery coefficients (RCs) and spillover ratios (SORs). Fifteen mice harbouring abdominal or subcutaneous tumours were imaged on clinical PET/CT with point spread function (PSF) reconstruction after injection of [18F]fluorodeoxyglucose or [18F]fluorothymidine. Three of these mice were imaged alone and simultaneously at radial positions -5, 0 and 5 cm. The remaining 12 tumour-bearing mice were imaged in groups of 3 to establish the quantitative accuracy of PET data using ex vivo gamma counting as the reference. Finally, a dynamic scan was performed in three mice simultaneously after the injection of 68 Ga-ethylenediaminetetraacetic acid (EDTA). For typical lesion sizes of 7-8 mm phantom experiments indicated RCs of 0.42 and 0.76 for ordered subsets expectation maximization (OSEM) and PSF reconstruction, respectively. For PSF reconstruction, SOR air and SOR water were 5.3 and 7.5%, respectively. A strong correlation (r 2 = 0.97, p 2 = 0.98; slope = 0.89, p 2 = 0.96; slope = 0.62, p 68 Ga-EDTA dynamic acquisition. New generation clinical PET/CT can be used for simultaneous imaging of multiple small animals in experiments requiring high throughput and where a dedicated small animal PET system is not available. (orig.)

  11. Statistical dynamic image reconstruction in state-of-the-art high-resolution PET

    International Nuclear Information System (INIS)

    Rahmim, Arman; Cheng, J-C; Blinder, Stephan; Camborde, Maurie-Laure; Sossi, Vesna

    2005-01-01

    Modern high-resolution PET is now more than ever in need of scrutiny into the nature and limitations of the imaging modality itself as well as image reconstruction techniques. In this work, we have reviewed, analysed and addressed the following three considerations within the particular context of state-of-the-art dynamic PET imaging: (i) the typical average numbers of events per line-of-response (LOR) are now (much) less than unity (ii) due to the physical and biological decay of the activity distribution, one requires robust and efficient reconstruction algorithms applicable to a wide range of statistics and (iii) the computational considerations in dynamic imaging are much enhanced (i.e., more frames to be stored and reconstructed). Within the framework of statistical image reconstruction, we have argued theoretically and shown experimentally that the sinogram non-negativity constraint (when using the delayed-coincidence and/or scatter-subtraction techniques) is especially expected to result in an overestimation bias. Subsequently, two schemes are considered: (a) subtraction techniques in which an image non-negativity constraint has been imposed and (b) implementation of random and scatter estimates inside the reconstruction algorithms, thus enabling direct processing of Poisson-distributed prompts. Both techniques are able to remove the aforementioned bias, while the latter, being better conditioned theoretically, is able to exhibit superior noise characteristics. We have also elaborated upon and verified the applicability of the accelerated list-mode image reconstruction method as a powerful solution for accurate, robust and efficient dynamic reconstructions of high-resolution data (as well as a number of additional benefits in the context of state-of-the-art PET)

  12. Ultra-fast bright field and fluorescence imaging of the dynamics of micrometer-sized objects

    Science.gov (United States)

    Chen, Xucai; Wang, Jianjun; Versluis, Michel; de Jong, Nico; Villanueva, Flordeliza S.

    2013-06-01

    High speed imaging has application in a wide area of industry and scientific research. In medical research, high speed imaging has the potential to reveal insight into mechanisms of action of various therapeutic interventions. Examples include ultrasound assisted thrombolysis, drug delivery, and gene therapy. Visual observation of the ultrasound, microbubble, and biological cell interaction may help the understanding of the dynamic behavior of microbubbles and may eventually lead to better design of such delivery systems. We present the development of a high speed bright field and fluorescence imaging system that incorporates external mechanical waves such as ultrasound. Through collaborative design and contract manufacturing, a high speed imaging system has been successfully developed at the University of Pittsburgh Medical Center. We named the system "UPMC Cam," to refer to the integrated imaging system that includes the multi-frame camera and its unique software control, the customized modular microscope, the customized laser delivery system, its auxiliary ultrasound generator, and the combined ultrasound and optical imaging chamber for in vitro and in vivo observations. This system is capable of imaging microscopic bright field and fluorescence movies at 25 × 106 frames per second for 128 frames, with a frame size of 920 × 616 pixels. Example images of microbubble under ultrasound are shown to demonstrate the potential application of the system.

  13. The usefulness of dynamic magnetic resonance imaging in the diagnosis of breast cancer

    International Nuclear Information System (INIS)

    Rugala, A.

    2003-01-01

    The purpose of this study was to determine the usefulness of dynamic MR in evaluation of breast cancer and to compare it with conventional mammography and US. The findings in 103 women were analyzed. MR examinations were performed on 0.5 Tesla system, using a dynamic sequence. All images were digitally subtracted. Histologic findings were correlated with preoperative mammographic, US and MR results.The combination of dynamic MR examination with mammography and sonography had the highest sensitivity: 87 from 90 focuses of cancer were correctly diagnosed. Malignant lesions in the standard method were found in 66 cases. Contrast enhanced MR imaging was superior to mammography and US when cancer was located close to the chest wall. Mammography and US were less accurate in identifying multifocal and multicentric cancer, when additional lesions were less then 2 cm. MR results proved to be the most accurate for the tumor size assessment. The combined method can be recommended where the highest possible sensitivity is desired. For correct diagnosis the digital subtraction technique of dynamic study is essential. MR imaging can facilitate the decision on the therapeutic approach in women with breast cancer, especially, when breast conserving therapy is considered. (author)

  14. Aspect-Aided Dynamic Non-Negative Sparse Representation-Based Microwave Image Classification

    Directory of Open Access Journals (Sweden)

    Xinzheng Zhang

    2016-09-01

    Full Text Available Classification of target microwave images is an important application in much areas such as security, surveillance, etc. With respect to the task of microwave image classification, a recognition algorithm based on aspect-aided dynamic non-negative least square (ADNNLS sparse representation is proposed. Firstly, an aspect sector is determined, the center of which is the estimated aspect angle of the testing sample. The training samples in the aspect sector are divided into active atoms and inactive atoms by smooth self-representative learning. Secondly, for each testing sample, the corresponding active atoms are selected dynamically, thereby establishing dynamic dictionary. Thirdly, the testing sample is represented with ℓ 1 -regularized non-negative sparse representation under the corresponding dynamic dictionary. Finally, the class label of the testing sample is identified by use of the minimum reconstruction error. Verification of the proposed algorithm was conducted using the Moving and Stationary Target Acquisition and Recognition (MSTAR database which was acquired by synthetic aperture radar. Experiment results validated that the proposed approach was able to capture the local aspect characteristics of microwave images effectively, thereby improving the classification performance.

  15. High-resolution dynamic pressure sensor array based on piezo-phototronic effect tuned photoluminescence imaging.

    Science.gov (United States)

    Peng, Mingzeng; Li, Zhou; Liu, Caihong; Zheng, Qiang; Shi, Xieqing; Song, Ming; Zhang, Yang; Du, Shiyu; Zhai, Junyi; Wang, Zhong Lin

    2015-03-24

    A high-resolution dynamic tactile/pressure display is indispensable to the comprehensive perception of force/mechanical stimulations such as electronic skin, biomechanical imaging/analysis, or personalized signatures. Here, we present a dynamic pressure sensor array based on pressure/strain tuned photoluminescence imaging without the need for electricity. Each sensor is a nanopillar that consists of InGaN/GaN multiple quantum wells. Its photoluminescence intensity can be modulated dramatically and linearly by small strain (0-0.15%) owing to the piezo-phototronic effect. The sensor array has a high pixel density of 6350 dpi and exceptional small standard deviation of photoluminescence. High-quality tactile/pressure sensing distribution can be real-time recorded by parallel photoluminescence imaging without any cross-talk. The sensor array can be inexpensively fabricated over large areas by semiconductor product lines. The proposed dynamic all-optical pressure imaging with excellent resolution, high sensitivity, good uniformity, and ultrafast response time offers a suitable way for smart sensing, micro/nano-opto-electromechanical systems.

  16. Comparison of time-series registration methods in breast dynamic infrared imaging

    Science.gov (United States)

    Riyahi-Alam, S.; Agostini, V.; Molinari, F.; Knaflitz, M.

    2015-03-01

    Automated motion reduction in dynamic infrared imaging is on demand in clinical applications, since movement disarranges time-temperature series of each pixel, thus originating thermal artifacts that might bias the clinical decision. All previously proposed registration methods are feature based algorithms requiring manual intervention. The aim of this work is to optimize the registration strategy specifically for Breast Dynamic Infrared Imaging and to make it user-independent. We implemented and evaluated 3 different 3D time-series registration methods: 1. Linear affine, 2. Non-linear Bspline, 3. Demons applied to 12 datasets of healthy breast thermal images. The results are evaluated through normalized mutual information with average values of 0.70 ±0.03, 0.74 ±0.03 and 0.81 ±0.09 (out of 1) for Affine, Bspline and Demons registration, respectively, as well as breast boundary overlap and Jacobian determinant of the deformation field. The statistical analysis of the results showed that symmetric diffeomorphic Demons' registration method outperforms also with the best breast alignment and non-negative Jacobian values which guarantee image similarity and anatomical consistency of the transformation, due to homologous forces enforcing the pixel geometric disparities to be shortened on all the frames. We propose Demons' registration as an effective technique for time-series dynamic infrared registration, to stabilize the local temperature oscillation.

  17. MR of normal pancreas : comparison of five pulse sequences and enhancing patterns on dynamic imaging

    International Nuclear Information System (INIS)

    Jang, Hyun Jung; Kim, Tae Kyoung; Hong, Sung Hwan; Han, Joon Koo; Choi, Byung Ihn

    1997-01-01

    To compare T1-weighted FLASH and turbo spin echo (SE) T2-weighted sequences with conventional T1- and T2-weighted sequences in imaging normal pancreas and to describe the enhancing patterns on dynamic MR imging. Forty-four patients with presumed hepatic hemangiomas were studied at 1.0T or 1.5T by using conventional SE sequences (T1-weighted, T2-weighted, and heavily T2-weighted), turbo-SE T2-weighted sequences, and breath-hold T1-weighted FLASH sequences acquired before, immediately on, and at 1, 2, 3, and 5 or 10 minutes after injection of a bolus of gadopentetate dimeglumine. No patients had either a history or its clinical features of pancreatic disease. Images were quantitatively analyzed for signal-difference-to noise ratios (SD/Ns) between the pancreas and peripancreatic fat. Percentage enhancement of the pancreas was measured on each dynamic MR image. Conspicuity of the pancreatic border was qualitatively evaluated according to a consensus, reached by three radiologists. Turbo-SE T2-weighted images had a significantly higher SD/N ratio (p<0.001) and better conspicuity of the pancreatic border (p<0.001) than SE T2- and heavily T2-weighted images;T1-weighted SE images had a significantly higher SD/N ratio than T1-weighted FLASH images (p<0.001), but there was no significant difference between tham in qualitative analysis (p=0.346). Percentage enhancement immediately on and at 1, 2, 3, 5, and 10 minutes after administration of contrast material was 39.9%, 44.5%, 42.9%, 40.8%, 36.3%, 29.9%, respectively, with peak enhancement at 1 minute. In MR imaging of normal pancreas, turbo-SE T2-weighted imaging is superior to SE T2- and heavily T2- weighted imaging, and SE T1-weighted imaging is superior to T1-weighted FLASH imaging. On serial gadolinium-enhanced FLASH imaging, normal pancreas shows peak enhancement at 1 minute

  18. New segmentation-based tone mapping algorithm for high dynamic range image

    Science.gov (United States)

    Duan, Weiwei; Guo, Huinan; Zhou, Zuofeng; Huang, Huimin; Cao, Jianzhong

    2017-07-01

    The traditional tone mapping algorithm for the display of high dynamic range (HDR) image has the drawback of losing the impression of brightness, contrast and color information. To overcome this phenomenon, we propose a new tone mapping algorithm based on dividing the image into different exposure regions in this paper. Firstly, the over-exposure region is determined using the Local Binary Pattern information of HDR image. Then, based on the peak and average gray of the histogram, the under-exposure and normal-exposure region of HDR image are selected separately. Finally, the different exposure regions are mapped by differentiated tone mapping methods to get the final result. The experiment results show that the proposed algorithm achieve the better performance both in visual quality and objective contrast criterion than other algorithms.

  19. Measurement of Two-Phase Flow Fields by Application of Dynamic Electrical Impedance Imaging

    International Nuclear Information System (INIS)

    Kim, KyungYoun; Kang, Sook In; Kim, Ho Chan; Kim, Sin; Lee, Yoon Joon; Kim, Min Chan; Anghaie, Samim

    2002-01-01

    This study presents a visualization technique for the phase distribution in a two-phase flow field with an electrical impedance imaging technique, which reconstructs the resistivity distribution with electrical responses that are determined by corresponding excitations. Special emphasis is placed on the development of dynamic imaging technique for two-phase system undergoing a rapid transient, which could not be visualized with conventional static imaging techniques. The proposed algorithm treats the image reconstruction problem as a nonlinear state estimation problem and the unknown state (resistivity distribution, i.e. phase distribution) is estimated with the aid of a Kalman filter in a minimum mean square error sense. Several illustrative examples with computer simulations are successfully provided to verify the reconstruction performance of the proposed algorithm. (authors)

  20. Observation of plasma-facing-wall via high dynamic range imaging

    International Nuclear Information System (INIS)

    Villamayor, Michelle Marie S.; Rosario, Leo Mendel D.; Viloan, Rommel Paulo B.

    2013-01-01

    Pictures of plasmas and deposits in a discharge chamber taken by varying shutter speeds have been integrated into high dynamic range (HDR) images. The HDR images of a graphite target surface of a compact planar magnetron (CPM) discharge device have clearly indicated the erosion pattern of the target, which are correlated to the light intensity distribution of plasma during operation. Based upon the HDR image technique coupled to colorimetry, a formation history of dust-like deposits inside of the CPM chamber has been recorded. The obtained HDR images have shown how the patterns of deposits changed in accordance with discharge duration. Results show that deposition takes place near the evacuation ports during the early stage of the plasma discharge. Discoloration of the plasma-facing-walls indicating erosion and redeposition eventually spreads at the periphery after several hours of operation. (author)

  1. Combined application of dynamic light scattering imaging and fluorescence intravital microscopy in vascular biology

    International Nuclear Information System (INIS)

    Kalchenko, V; Harmelin, A; Ziv, K; Addadi, Y; Madar-Balakirski, N; Neeman, M; Meglinski, I

    2010-01-01

    The dynamic light scattering imaging (DLSI) system combined with the conventional fluorescence intravital microscope (FIM) has been applied for the examination of blood and lymph vessels in the mouse ear in vivo. While the CCD camera can be shared by both techniques the combined application of DLSI and FIM allows rapid switching between the modalities. In current study temporal speckles fluctuations are used for rendering blood vessels structure and monitoring blood perfusion with the higher spatial resolution, whereas FIM provides the images of lymphatic vessels. The results clearly demonstrate that combined application of DLSI and FIM approaches provides synchronic in vivo images of blood and lymph vessels with higher contrast and specificity. The use of this new dual-modal diagnostic system is particularly important and has a great potential to significantly expand the capabilities of vascular diagnostics providing synchronic in vivo images of blood and lymph vessels

  2. Segmentation of rodent whole-body dynamic PET images: an unsupervised method based on voxel dynamics

    DEFF Research Database (Denmark)

    Maroy, Renaud; Boisgard, Raphaël; Comtat, Claude

    2008-01-01

    Positron emission tomography (PET) is a useful tool for pharmacokinetics studies in rodents during the preclinical phase of drug and tracer development. However, rodent organs are small as compared to the scanner's intrinsic resolution and are affected by physiological movements. We present a new...... method for the segmentation of rodent whole-body PET images that takes these two difficulties into account by estimating the pharmacokinetics far from organ borders. The segmentation method proved efficient on whole-body numerical rat phantom simulations, including 3-14 organs, together...

  3. Quantification of renal cortical blood flow using factor analysis of O-15 water dynamic PET images

    International Nuclear Information System (INIS)

    Seo, Kang Jun; Ahn, Ji Young; Lee, Jae Sung; Paeng, Jin Chul; Cheon, Gi Jeong; Lee, Dong Soo; Noh, Tae Won; Chung, June Key; Lee, Myung Chul

    2000-01-01

    To obtain spatial distribution of renal factor images, input function, and regional tissue time-activity curve (TAC) from O-15 water dynamic PET images non-invasively, factor analysis (FA) was used. O-15 water dynamic PET scans were performed on 3 normal dogs (22 ∼ 29 kg) with the bolus injection of O-15 water (555 ∼ 740 Mbq). We performed FA on the masked dynamic images and obtained the pure TACs and the corresponding factor images. Microsphere experiment also was performed. 37MBq of microsphere labeled with Sc-46 was injected into the left ventricle. Arterial input functions derived from the PET images using FA were compared with the invasively derived arterial blood samples. The renal cortical blood flow using the TACs by FA was within the normal range of 1.23 ∼ 2.46 ml/min/g. In microsphere study, the renal cortical blood flow of left kidney by FA was 2.49±0.47 ml/min/g (1.81∼2.90 ml/min/g) and by microsphere was 2.52 ±0.19 ml/min/g (2.34 ∼2.68 ml/min/g). In right kidney, flow by FA was 2.02 ±0.32 ml/min/g (1.82∼2.49 ml/min/g) and by microsphere was 2.49 ±0.27 ml/min/g (2.02∼2.7). FA is a useful and robust method to extract input functions and tissue TACs from O-15 dynamic renal PET. Renal cortical blood flow can be estimated non-invasively using FA and it will be helpful for the assessment of renal functional disease

  4. Magnitude and extent of land subsidence in central Mexico revealed by regional InSAR ALOS time-series survey

    Science.gov (United States)

    Chaussard, E.; Wdowinski, S.; Amelung, F.; Cabral-Cano, E.

    2013-05-01

    Massive groundwater extraction is very common in Mexico and is well known to result in land subsidence. However, most surveys dedicated to land subsidence focus on one single city, mainly Mexico City, and thus fail to provide a comprehensive picture of the problem. Here we use a space-based radar remote sensing technique, known as Interferometric Synthetic Aperture Radar (InSAR) to detect land subsidence in the entire central Mexico area. We used data from the Japanese satellite ALOS, processed over 600 SAR images acquired between 2007-2011 and produced over 3000 interferograms to cover and area of 200,000 km2 in central Mexico. We identify land subsidence in twenty-one areas, including seventeen cities, namely from east to west, Puebla, Mexico city, Toluca de Lerdo, Queretaro, San Luis de la Paz, south of San Luis de la Paz, Celaya, south of Villa de Reyes, San Luis Potosi, west of Villa de Arista, Morelia, Salamanca, Irapuato, Silao, Leon, Aguascalientes, north of Aguascalientes, Zamora de Hidalgo, Guadalajara, Ahuacatlan, and Tepic. Subsidence rates of 30 cm/yr are observed in Mexico City, while in the other locations typical rates of 5-10 cm/yr are noticed. Regional surveys of this type are necessary for the development of hazard mitigation plans and efficient use of ground-based monitoring. We additionally correlate subsidence with land use, surface geology, and faults distribution and suggest that groundwater extraction for agricultural, urban, and industrial uses are the main causes of land subsidence. We also reveal that the limits of the subsiding areas often correlate with existing faults, motion on these faults being driven by water extraction rather than by tectonic activity. In all the subsiding locations we observe high ground velocity gradients emphasizing the significant risks associated with land subsidence in central Mexico. Averaged 2007-2011 ground velocity map from ALOS InSAR time-series in central Mexico, revealing land subsidence in 21

  5. A prototype of an automated high resolution InSAR volcano-monitoring system in the MED-SUV project

    Science.gov (United States)

    Chowdhury, Tanvir A.; Minet, Christian; Fritz, Thomas

    2016-04-01

    Volcanic processes which produce a variety of geological and hydrological hazards are difficult to predict and capable of triggering natural disasters on regional to global scales. Therefore it is important to monitor volcano continuously and with a high spatial and temporal sampling rate. The monitoring of active volcanoes requires the reliable measurement of surface deformation before, during and after volcanic activities and it helps for the better understanding and modelling of the involved geophysical processes. Space-borne synthetic aperture radar (SAR) interferometry (InSAR), persistent scatterer interferometry (PSI) and small baseline subset algorithm (SBAS) provide a powerful tool for observing the eruptive activities and measuring the surface changes of millimetre accuracy. All the mentioned techniques with deformation time series extraction address the challenges by exploiting medium to large SAR image stacks. The process of selecting, ordering, downloading, storing, logging, extracting and preparing the data for processing is very time consuming has to be done manually for every single data-stack. In many cases it is even an iterative process which has to be done regularly and continuously. Therefore, data processing becomes slow which causes significant delays in data delivery. The SAR Satellite based High Resolution Data Acquisition System, which will be developed at DLR, will automate this entire time consuming tasks and allows an operational volcano monitoring system. Every 24 hours the system runs for searching new acquired scene over the volcanoes and keeps track of the data orders, log the status and download the provided data via ftp-transfer including E-Mail alert. Furthermore, the system will deliver specified reports and maps to a database for review and use by specialists. The user interaction will be minimized and iterative processes will be totally avoided. In this presentation, a prototype of SAR Satellite based High Resolution Data

  6. Segmentation of rodent whole-body dynamic PET images: an unsupervised method based on voxel dynamics

    International Nuclear Information System (INIS)

    Maroy, R.; Boisgard, R.; Comtat, C.; Dolle, F.; Trebossen, R.; Tavitian, B.; Frouin, V.; Cathier, P.; Duchesnay, E.; D; Nielsen, P.E.

    2008-01-01

    Positron emission tomography (PET) is a useful tool for pharmacokinetics studies in rodents during the preclinical phase of drug and tracer development. However, rodent organs are small as compared to the scanner's intrinsic resolution and are affected by physiological movements. We present a new method for the segmentation of rodent whole-body PET images that takes these two difficulties into account by estimating the pharmacokinetics far from organ borders. The segmentation method proved efficient on whole-body numerical rat phantom simulations, including 3-14 organs, together with physiological movements (heart beating, breathing, and bladder filling). The method was resistant to spillover and physiological movements, while other methods failed to obtain a correct segmentation. The radioactivity concentrations calculated with this method also showed an excellent correlation with the manual delineation of organs in a large set of preclinical images. In addition, it was faster, detected more organs, and extracted organs' mean time activity curves with a better confidence on the measure than manual delineation. (authors)

  7. Monitoring the UPS and Downs of Sumatra and Java with D-Insar Time-Series

    Science.gov (United States)

    Chaussard, E.; Amelung, F.

    2010-12-01

    We performed, for the first time, a global D-InSAR survey of the Indonesian islands of Sumatra and Java to define locations where deformation is occurring. The goals of this study are 1) to create an inventory of actively deforming volcanic centers and 2) monitor all types of ground motion. This work provides ground deformation data for previously unmonitored areas and can assist the Indonesian authorities to improve hazards assessment. The D-InSAR survey covers an area of about 500 000 km2 and 3000 km long on the islands of Sumatra, Java and Bali. We used ALOS data from 45 tracks and more than 1500 granules obtained from the Alaska Satellite Facility (ASF) through the US Government Research Consortium (USGRC). We completed more than 1000 interferograms spanning a period from the end of 2006 to the beginning of 2009. L-band SAR images enable deformation mapping at global scales even in highly vegetated areas where C-band signal experiences loss of coherence. To identify locations where ground deformations are occurring, we used multiple SAR acquisitions of the same area and performed time series analysis using the Small BAseline Subset (SBAS) method. Interferograms with a maximum spatial baseline of 3000 m were phase-unwrapped and subsequently inverted for the phase with respect to the first acquisition. Temporal coherence of each pixel is computed on the set of interferograms in order to select only pixels with high temporal coherence. The compiled InSAR velocity map reveals the background level of activity of the 84 volcanic centers constituting the Sumatra, Java and Bali volcanic arcs. We identified possible uplift at 6 volcanic centers: Agung (Bali), Lamongan (Java), Lawu (Java), Slamet (Java), Kerinci (Sumatra) and Sinabung (Sumatra). Moreover, we identified subsidence in 5 major cities and 1 coastal area. Subsidence rates range from 6 cm/yr in Medan, the largest city of Sumatra, to more than 15 cm/yr in Jakarta. These major subsidence areas are probably due

  8. Dynamic PET and Optical Imaging and Compartment Modeling using a Dual-labeled Cyclic RGD Peptide Probe

    Directory of Open Access Journals (Sweden)

    Lei Zhu, Ning Guo, Quanzheng Li, Ying Ma, Orit Jacboson, Seulki Lee, Hak Soo Choi, James R. Mansfield, Gang Niu, Xiaoyuan Chen

    2012-01-01

    Full Text Available Purpose: The aim of this study is to determine if dynamic optical imaging could provide comparable kinetic parameters to that of dynamic PET imaging by a near-infrared dye/64Cu dual-labeled cyclic RGD peptide.Methods: The integrin αvβ3 binding RGD peptide was conjugated with a macrocyclic chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA for copper labeling and PET imaging and a near-infrared dye ZW-1 for optical imaging. The in vitro biological activity of RGD-C(DOTA-ZW-1 was characterized by cell staining and receptor binding assay. Sixty-min dynamic PET and optical imaging were acquired on a MDA-MB-435 tumor model. Singular value decomposition (SVD method was applied to compute the dynamic optical signal from the two-dimensional optical projection images. Compartment models were used to quantitatively analyze and compare the dynamic optical and PET data.Results: The dual-labeled probe 64Cu-RGD-C(DOTA-ZW-1 showed integrin specific binding in vitro and in vivo. The binding potential (Bp derived from dynamic optical imaging (1.762 ± 0.020 is comparable to that from dynamic PET (1.752 ± 0.026.Conclusion: The signal un-mixing process using SVD improved the accuracy of kinetic modeling of 2D dynamic optical data. Our results demonstrate that 2D dynamic optical imaging with SVD analysis could achieve comparable quantitative results as dynamic PET imaging in preclinical xenograft models.

  9. Imaging the equilibrium state and magnetization dynamics of partially built hard disk write heads

    Energy Technology Data Exchange (ETDEWEB)

    Valkass, R. A. J., E-mail: rajv202@ex.ac.uk; Yu, W.; Shelford, L. R.; Keatley, P. S.; Loughran, T. H. J.; Hicken, R. J. [School of Physics, University of Exeter, Stocker Road, Exeter EX4 4QL (United Kingdom); Cavill, S. A. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Department of Physics, University of York, Heslington, York YO10 5DD (United Kingdom); Laan, G. van der; Dhesi, S. S. [Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE (United Kingdom); Bashir, M. A.; Gubbins, M. A. [Research and Development, Seagate Technology, 1 Disc Drive, Springtown Industrial Estate, Derry BT48 0BF (United Kingdom); Czoschke, P. J.; Lopusnik, R. [Recording Heads Operation, Seagate Technology, 7801 Computer Avenue South, Bloomington, Minnesota 55435 (United States)

    2015-06-08

    Four different designs of partially built hard disk write heads with a yoke comprising four repeats of NiFe (1 nm)/CoFe (50 nm) were studied by both x-ray photoemission electron microscopy (XPEEM) and time-resolved scanning Kerr microscopy (TRSKM). These techniques were used to investigate the static equilibrium domain configuration and the magnetodynamic response across the entire structure, respectively. Simulations and previous TRSKM studies have made proposals for the equilibrium domain configuration of similar structures, but no direct observation of the equilibrium state of the writers has yet been made. In this study, static XPEEM images of the equilibrium state of writer structures were acquired using x-ray magnetic circular dichroism as the contrast mechanism. These images suggest that the crystalline anisotropy dominates the equilibrium state domain configuration, but competition with shape anisotropy ultimately determines the stability of the equilibrium state. Dynamic TRSKM images were acquired from nominally identical devices. These images suggest that a longer confluence region may hinder flux conduction from the yoke into the pole tip: the shorter confluence region exhibits clear flux beaming along the symmetry axis, whereas the longer confluence region causes flux to conduct along one edge of the writer. The observed variations in dynamic response agree well with the differences in the equilibrium magnetization configuration visible in the XPEEM images, confirming that minor variations in the geometric design of the writer structure can have significant effects on the process of flux beaming.

  10. Contrast-enhanced dynamic MR imaging of parasellar tumor using fast spin-echo sequence

    International Nuclear Information System (INIS)

    Kusunoki, Katsusuke; Ohue, Shiro; Ichikawa, Haruhisa; Saito, Masahiro; Sadamoto, Kazuhiko; Sakaki, Saburo; Miki, Hitoshi.

    1995-01-01

    We have applied a new dynamic MRI technique that uses a fast spin-echo sequence to parasellar tumors. This sequence has less susceptible effect and better spatial resolution than a gradient echo sequence, providing faster images than a short spin-echo sequence does. Image was obtained in the coronal or sagittal plane using a 1.5T clinical MRI system, and then, dynamic MR images were acquired every 10 to 20 sec after administration of Gd-DTPA (0.1 mmol/kg). The subjects were 12 patients (5 microadenomas, 5 macroadenomas and 2 Rathke's cleft cysts) and 5 normal volunteers. As for volunteers, the cavernous sinus, pituitary stalk and posterior pituitary gland were contrasted on the first image, followed by visualization of the proximal portion adjacent to the junction of the infundibulum and the anterior pituitary gland, and finally by contrasting the distal portion of the anterior pituitary gland. There was a difference with respect to tumor contrast between microadenomas and macroadenomas. In the case of the macroadenomas, the tumor was contrasted at the same time as, or faster than the anterior pituitary gland, while with the microadenomas the tumor was enhanced later than the anterior pituitary gland. No enhancement with contrast medium was seen in Rathke's cleft cysts. In addition, it was possible to differentiate a recurrent tumor from a piece of muscle placed at surgery since the images obtained by the fast spin-echo sequence were clearer than those obtained by gradient echo sequence. (author)

  11. Differentiation of recurrent breast cancer from radiation fibrosis with dynamic gadolinium-enhanced MR imaging

    International Nuclear Information System (INIS)

    Dao, T.H.; Campana, F.; Fourquet, A.; Rahmouni, A.

    1991-01-01

    This paper assesses the ability of dynamic gadolinium-enhanced MR imaging to differentiate radiation fibrosis from tumor recurrence of breast cancer after conservative treatment. Twenty-five women with previous breast cancer treated with radiation therapy underwent MR imaging examination. Tumor recurrence was suspected on palpation of masses (18 cases) or at mammography (7 cases). The MR imaging protocol was performed on a 0.5-T imager with a breast coil and included T1 and T2 spin-echo, short To inversion recovery (STIR), and dynamic gadolinium-enhanced T1-weighted sequenced to evaluate the hemokinetics of the lesion. Ratios of signal intensity of suspected lesions to that of fat, surrounding breast gland, and background noise were calculated. Percutaneous biopsies were performed in all cases after MR imaging. Curves of signal-to-noise ratio of recurrences (5 cases) showed an early enhancement within the first minutes after injection, although localized fibrosis (20 cases) was not significantly enhanced. T2 and STIR sequences were not contributive in differentiating fibrosis from tumor recurrence

  12. Multimodal breast cancer imaging using coregistered dynamic diffuse optical tomography and digital breast tomosynthesis

    Science.gov (United States)

    Zimmermann, Bernhard B.; Deng, Bin; Singh, Bhawana; Martino, Mark; Selb, Juliette; Fang, Qianqian; Sajjadi, Amir Y.; Cormier, Jayne; Moore, Richard H.; Kopans, Daniel B.; Boas, David A.; Saksena, Mansi A.; Carp, Stefan A.

    2017-04-01

    Diffuse optical tomography (DOT) is emerging as a noninvasive functional imaging method for breast cancer diagnosis and neoadjuvant chemotherapy monitoring. In particular, the multimodal approach of combining DOT with x-ray digital breast tomosynthesis (DBT) is especially synergistic as DBT prior information can be used to enhance the DOT reconstruction. DOT, in turn, provides a functional information overlay onto the mammographic images, increasing sensitivity and specificity to cancer pathology. We describe a dynamic DOT apparatus designed for tight integration with commercial DBT scanners and providing a fast (up to 1 Hz) image acquisition rate to enable tracking hemodynamic changes induced by the mammographic breast compression. The system integrates 96 continuous-wave and 24 frequency-domain source locations as well as 32 continuous wave and 20 frequency-domain detection locations into low-profile plastic plates that can easily mate to the DBT compression paddle and x-ray detector cover, respectively. We demonstrate system performance using static and dynamic tissue-like phantoms as well as in vivo images acquired from the pool of patients recalled for breast biopsies at the Massachusetts General Hospital Breast Imaging Division.

  13. High-dynamic range compressive spectral imaging by grayscale coded aperture adaptive filtering

    Directory of Open Access Journals (Sweden)

    Nelson Eduardo Diaz

    2015-09-01

    Full Text Available The coded aperture snapshot spectral imaging system (CASSI is an imaging architecture which senses the three dimensional informa-tion of a scene with two dimensional (2D focal plane array (FPA coded projection measurements. A reconstruction algorithm takes advantage of the compressive measurements sparsity to recover the underlying 3D data cube. Traditionally, CASSI uses block-un-block coded apertures (BCA to spatially modulate the light. In CASSI the quality of the reconstructed images depends on the design of these coded apertures and the FPA dynamic range. This work presents a new CASSI architecture based on grayscaled coded apertu-res (GCA which reduce the FPA saturation and increase the dynamic range of the reconstructed images. The set of GCA is calculated in a real-time adaptive manner exploiting the information from the FPA compressive measurements. Extensive simulations show the attained improvement in the quality of the reconstructed images when GCA are employed.  In addition, a comparison between traditional coded apertures and GCA is realized with respect to noise tolerance.

  14. X-ray phase imaging-From static observation to dynamic observation-

    International Nuclear Information System (INIS)

    Momose, A.; Yashiro, W.; Olbinado, M. P.; Harasse, S.

    2012-01-01

    We are attempting to expand the technology of X-ray grating phase imaging/tomography to enable dynamic observation. X-ray phase imaging has been performed mainly for static cases, and this challenge is significant since properties of materials (and hopefully their functions) would be understood by observing their dynamics in addition to their structure, which is an inherent advantage of X-ray imaging. Our recent activities in combination with white synchrotron radiation for this purpose are described. Taking advantage of the fact that an X-ray grating interferometer functions with X-rays of a broad energy bandwidth (and therefore high flux), movies of differential phase images and visibility images are obtained with a time resolution of a millisecond. The time resolution of X-ray phase tomography can therefore be a second. This study is performed as a part of a project to explore X-ray grating interferometry, and our other current activities are also briefly outlined.

  15. Pyroclastic Flow Deposits and InSAR: Analysis of Long-Term Subsidence at Augustine Volcano, Alaska

    Directory of Open Access Journals (Sweden)

    David B. McAlpin

    2016-12-01

    Full Text Available Deformation of pyroclastic flow deposits begins almost immediately after emplacement, and continues thereafter for months or years. This study analyzes the extent, volume, thickness, and variability in pyroclastic flow deposits (PFDs on Augustine Volcano from measuring their deformation rates with interferometric synthetic aperture radar (InSAR. To conduct this analysis, we obtained 48 SAR images of Augustine Volcano acquired between 1992 and 2010, spanning its most recent eruption in 2006. The data were processed using d-InSAR time-series analysis to measure the thickness of the Augustine PFDs, as well as their surface deformation behavior. Because much of the 2006 PFDs overlie those from the previous eruption in 1986, geophysical models were derived to decompose deformation contributions from the 1986 deposits underlying the measured 2006 deposits. To accomplish this, we introduce an inversion approach to estimate geophysical parameters for both 1986 and 2006 PFDs. Our analyses estimate the expanded volume of pyroclastic flow material deposited during the 2006 eruption to be 3.3 × 107 m3 ± 0.11 × 107 m3, and that PFDs in the northeastern part of Augustine Island reached a maximum thickness of ~31 m with a mean of ~5 m. Similarly, we estimate the expanded volume of PFDs from the 1986 eruption at 4.6 × 107 m3 ± 0.62 × 107 m3, with a maximum thickness of ~31 m, and a mean of ~7 m.

  16. Land Subsidence Monitoring by InSAR Time Series Technique Derived From ALOS-2 PALSAR-2 over Surabaya City, Indonesia

    Science.gov (United States)

    Aditiya, A.; Takeuchi, W.; Aoki, Y.

    2017-12-01

    Surabaya is the second largest city in Indonesia and the capital of East Java Province with rapid population and industrialization. The impact of urbanization in the big city can suffer potential disasters either nature or anthropogenic such as land subsidence and flood. The pattern of land subsidence need to be mapped for the purposes of planning and structuring the city as well as taking appropriate policy in anticipating and mitigating the impact. This research has used interferometric Synthetic Aperture Radar (InSAR) Small Baseline Subset (SBAS) technique and applied time series analysis to investigate land subsidence occured. The technique includes the process of focusing the SAR data, incorporating the precise orbit, generating interferogram and phase unwrapping using SNAPHU algorithms. The results showed land subsidence has been detected during 2014-2017 over Surabaya city area using ALOS-2/PALSAR-2 images data. These results reveal the subsidence has observed in several area in Surabaya in particular northern part reach up to ∼2 cm/year. The fastest subsidence occurs in highly populated areas suffer vulnerable to flooding and sea level rise impact. In urban areas we found a correlation between land subsidence with residential or industrial land use. It concludes that land subsidence is mainly caused by ground water consumption for industrial and residential use respectively.

  17. Dynamic gadolinium-enhanced MR imaging in active and inactive immunoinflammatory gonarthritis

    DEFF Research Database (Denmark)

    Østergaard, Mikkel; Lorenzen, I; Henriksen, O

    1994-01-01

    examined 16 clinically active (CAG), 7 clinically inactive (CIG) and 4 healthy knees. The synovium of a preselected slice was outlined. Its area and relative signal intensity increase after gadopentetate dimeglumine on T1-SE and FLASH (at each time t) were calculated. The CAG knees showed a mean signal...... intensity increase on early dynamic FLASH images higher by far than the CIG knees, while no significant difference was found on spin-echo images obtained 5 to 15 min after contrast injection. The early signal enhancement probably reflects the perfusion and capillary permeability of the synovium. The area...

  18. Solitary hepatic infantile hemangioendothelioma: dynamic gadolinium-enhanced MR imaging findings

    International Nuclear Information System (INIS)

    Mortele, Koenraad J.; Vanzieleghem, Bart; Mortele, Bart; Benoit, Yves; Ros, Pablo R.

    2002-01-01

    We report the MRI findings of a solitary hepatic infantile hemangioendothelioma (IHE) diagnosed in a 14-day-old girl. To the best of our knowledge, only one report has illustrated the dynamic gadolinium-enhanced MR imaging features of IHE previously. Compounding the rarity of presentation as a solitary mass, the gadolinium-enhanced MRI appearance in our case is unique, because the IHE showed an early rim-like pseudocapsular enhancement followed by progressive fill-in of the lesion on delayed imaging. (orig.)

  19. In-vivo imaging of blood flow dynamics using color Doppler optical coherence tomography

    Science.gov (United States)

    Yazdanfar, Siavash; Rollins, Andrew M.; Izatt, Joseph A.

    2000-04-01

    Noninvasive quantitation of blood flow in the retinal micro circulation may elucidate the progression and treatment of ocular disorders including diabetic retinopathy, age-related degeneration, and glaucoma. Color Doppler optical coherence tomography was recently introduced as a technique allowing simultaneous micron-scale resolution cross-sectional imaging of tissue micro structure and blood flow in the human retina. Here, time-resolved imaging of dynamics of blood flow profiles was performed to measure cardiac pulsatility within retinal vessels. Retinal pulsatility has been shown to decrease throughout the progression of diabetic retinopathy.

  20. Disparity Map Generation from Illumination Variant Stereo Images Using Efficient Hierarchical Dynamic Programming

    Directory of Open Access Journals (Sweden)

    Viral H. Borisagar

    2014-01-01

    Full Text Available A novel hierarchical stereo matching algorithm is presented which gives disparity map as output from illumination variant stereo pair. Illumination difference between two stereo images can lead to undesirable output. Stereo image pair often experience illumination variations due to many factors like real and practical situation, spatially and temporally separated camera positions, environmental illumination fluctuation, and the change in the strength or position of the light sources. Window matching and dynamic programming techniques are employed for disparity map estimation. Good quality disparity map is obtained with the optimized path. Homomorphic filtering is used as a preprocessing step to lessen illumination variation between the stereo images. Anisotropic diffusion is used to refine disparity map to give high quality disparity map as a final output. The robust performance of the proposed approach is suitable for real life circumstances where there will be always illumination variation between the images. The matching is carried out in a sequence of images representing the same scene, however in different resolutions. The hierarchical approach adopted decreases the computation time of the stereo matching problem. This algorithm can be helpful in applications like robot navigation, extraction of information from aerial surveys, 3D scene reconstruction, and military and security applications. Similarity measure SAD is often sensitive to illumination variation. It produces unacceptable disparity map results for illumination variant left and right images. Experimental results show that our proposed algorithm produces quality disparity maps for both wide range of illumination variant and invariant stereo image pair.

  1. Local contrast-enhanced MR images via high dynamic range processing.

    Science.gov (United States)

    Chandra, Shekhar S; Engstrom, Craig; Fripp, Jurgen; Neubert, Ales; Jin, Jin; Walker, Duncan; Salvado, Olivier; Ho, Charles; Crozier, Stuart

    2018-09-01

    To develop a local contrast-enhancing and feature-preserving high dynamic range (HDR) image processing algorithm for multichannel and multisequence MR images of multiple body regions and tissues, and to evaluate its performance for structure visualization, bias field (correction) mitigation, and automated tissue segmentation. A multiscale-shape and detail-enhancement HDR-MRI algorithm is applied to data sets of multichannel and multisequence MR images of the brain, knee, breast, and hip. In multisequence 3T hip images, agreement between automatic cartilage segmentations and corresponding synthesized HDR-MRI series were computed for mean voxel overlap established from manual segmentations for a series of cases. Qualitative comparisons between the developed HDR-MRI and standard synthesis methods were performed on multichannel 7T brain and knee data, and multisequence 3T breast and knee data. The synthesized HDR-MRI series provided excellent enhancement of fine-scale structure from multiple scales and contrasts, while substantially reducing bias field effects in 7T brain gradient echo, T 1 and T 2 breast images and 7T knee multichannel images. Evaluation of the HDR-MRI approach on 3T hip multisequence images showed superior outcomes for automatic cartilage segmentations with respect to manual segmentation, particularly around regions with hyperintense synovial fluid, across a set of 3D sequences. The successful combination of multichannel/sequence MR images into a single-fused HDR-MR image format provided consolidated visualization of tissues within 1 omnibus image, enhanced definition of thin, complex anatomical structures in the presence of variable or hyperintense signals, and improved tissue (cartilage) segmentation outcomes. © 2018 International Society for Magnetic Resonance in Medicine.

  2. Application of InSAR and Gravimetry for Land Subsidence Hazard Zoning in Aguascalientes, Mexico

    OpenAIRE

    Pacheco-Martínez, Jesús; Cabral-Cano, Enrique; Wdowinski, Shimon; Hernández-Marín, Martín; Ortiz-Lozano, José; Zermeño-de-León, Mario

    2015-01-01

    In this work we present an application of InSAR and gravimetric surveys for risk management related to land subsidence and surface ground faulting generation. A subsidence velocity map derived from the 2007–2011 ALOS SAR imagery and a sediment thicknesses map obtained from the inversion of gravimetric data were integrated with a surface fault map to produce a subsidence hazard zoning in the city of Aguascalientes, Mexico. The resulting zoning is presented together with specific recommendation...

  3. Using InSAR for Characterizing Pyroclastic Flow Deposits at Augustine Volcano Across Two Eruptive Cycles

    Science.gov (United States)

    McAlpin, D. B.; Meyer, F. J.; Lu, Z.; Beget, J. E.

    2014-12-01

    Augustine Island is a small, 8x11 km island in South Central Alaska's lower Cook Inlet. It is approximately 280 km southwest of Anchorage, and occupied entirely by its namesake Augustine Volcano. At Augustine Volcano, SAR data suitable for interferometry is available from 1992 to 2005, from March 2006 to April 2007, and from July 2007 to October 2010. Its last two eruptive episodes, in 1986 and 2006, resulted in substantial pyroclastic flow deposits (PFDs) on the Volcano's north flank. Earlier InSAR analyses of the area, from 1992-1999, identified local subsidence, but no volcano-wide deformation indicative of magma-chamber evacuation. In contrast to previous studies, we use InSAR data to determine a range of geophysical parameters for PFDs emplaced during the Augustine's two most recent eruption cycles. Based on InSAR measurements between 1992 and 2010, we reconstruct the deformation behavior of PFDs emplaced during Augustine's last two eruption cycles. Using a combination of InSAR measurements and modeling, we determine the thickness and long-term deformation of overlaying pyroclastic flow deposits emplaced in 1986 and 2006. Consistent with previous observations of pyroclastic flows, we found that the PFDs on Augustine Island rapidly subsided after emplacement due to an initial compaction of the material. We determined the length of this initial settling period and measured the compaction rate. Subsequent to this initial rapid subsidence, we found that PFD deformation slowed to a more persistent, linear, long-term rate, related to cooling of the deposits. We established that the deposits' contraction rate is linearly related to their thickness and measured the contraction rate. Finally, a study of long term coherence properties of the Augustine PFDs showed remarkable stability of the surface over long time periods. This information provides clues on the structural properties and composition of the emplaced material.

  4. Interseismic Deformation along the Red River Fault from InSAR Measurements

    Science.gov (United States)

    Chen, J.; Li, Z.; Clarke, P. J.

    2017-12-01

    The Red River Fault (RRF) zone is a profound geological discontinuity separating South China from Indochina. Right lateral movements along this >900 km fault are considered to accommodate the extrusion of SE China. Crustal deformation monitoring at high resolution is the key to understand the present-day mode of deformation in this zone and its interaction with the adjacent regions. This is the first study to measure the interseismic deformation of the entire fault with ALOS-1/2 and Sentinel-1 observations. Nine ascending tracks of ALOS-1 data between 2007 and 2011 are collected from the Alaska Satellite Facility (ASF), four descending tracks of Sentinel-1 data are acquired every 24 days since October 2014, and ALOS-2 data are being systematically acquired since 2014. The long wavelength (L-band) of ALOS-1/2 and short temporal baseline of Sentinel-1 ensure good coherence to overcome the limitations of heavy vegetation and variable climate in the region. Stacks of interferograms are generated by our automatic processing chain based on the InSAR Scientific Computing Environment (ISCE) software, ionospheric errors are estimated and corrected using the split-spectrum method (Fattahi et al., IEEE Trans. Geosci. Remote Sens., 2017) and the tropospheric delays are calibrated using the Generic Atmospheric Correction Online Service for InSAR (GACOS: http://ceg-research.ncl.ac.uk/v2/gacos) with high-resolution ECMWF products (Yu et al., J. Geophys. Res., 2017). Time series analysis is performed to determine the interseismic deformation rate of the RRF using the in-house InSAR time series with atmospheric estimation model (InSAR TS + AEM) package based on the Small Baseline Subset (SBAS) algorithm. Our results reveal the decrease of slip rate from north to south. We map the interseismic strain rate field to characterize the deformation patterns and seismic hazard throughout the RRF zone.

  5. Short repetition time multiband echo-planar imaging with simultaneous pulse recording allows dynamic imaging of the cardiac pulsation signal.

    Science.gov (United States)

    Tong, Yunjie; Hocke, Lia M; Frederick, Blaise deB

    2014-11-01

    Recently developed simultaneous multislice echo-planar imaging (EPI) sequences permit imaging of the whole brain at short repetition time (TR), allowing the cardiac fluctuations to be fully sampled in blood-oxygen-level dependent functional MRI (BOLD fMRI). A novel low computational analytical method was developed to dynamically map the passage of the pulsation signal through the brain and visualize the whole cerebral vasculature affected by the pulse signal. This algorithm is based on a simple combination of fast BOLD fMRI and the scanner's own built-in pulse oximeter. Multiple, temporally shifted copies of the pulse oximeter data (with 0.08 s shifting step and coverage of a 1-s span) were downsampled and used as cardiac pulsation regressors in a general linear model based analyses (FSL) of the fMRI data. The resulting concatenated z-statistics maps show the voxels that are affected as the cardiac signal travels through the brain. Many voxels were highly correlated with the pulsation regressor or its temporally shifted version. The dynamic and static cardiac pulsation maps obtained from both the task and resting state scans, resembled cerebral vasculature. The results demonstrated: (i) cardiac pulsation significantly affects most voxels in the brain; (ii) combining fast fMRI and this analytical method can reveal additional clinical information to functional studies. Copyright © 2013 Wiley Periodicals, Inc.

  6. Imaging of vascular dynamics within the foot using dynamic diffuse optical tomography to diagnose peripheral arterial disease

    Science.gov (United States)

    Khalil, M. A.; Kim, H. K.; Hoi, J. W.; Kim, I.; Dayal, R.; Shrikande, G.; Hielscher, A. H.

    2013-03-01

    Peripheral Arterial Disease (PAD) is the narrowing of the functional area of the artery generally due to atherosclerosis. It affects between 8-12 million people in the United States and if untreated this can lead to ulceration, gangrene and ultimately amputation. The current diagnostic method for PAD is the ankle-brachial index (ABI). The ABI is a ratio of the patient's systolic blood pressure in the foot to that of the brachial artery in the arm, a ratio below 0.9 is indicative of affected vasculature. However, this method is ineffective in patients with calcified arteries (diabetic and end-stage renal failure patients), which falsely elevates the ABI recording resulting in a false negative reading. In this paper we present our results in a pilot study to deduce optical tomography's ability to detect poor blood perfusion in the foot. We performed an IRB approved 30 patient study, where we imaged the feet of the enrolled patients during a five stage dynamic imaging sequence. The patients were split up into three groups: 10 healthy subjects, 10 PAD patients and 10 PAD patients with diabetes and they were imaged while applying a pressure cuff to their thigh. Differences in the magnitude of blood pooling in the foot and rate at which the blood pools in the foot are all indicative of arterial disease.

  7. Assessment of myocardial viability by dynamic tomographic iodine 123 iodophenylpentadecanoic acid imaging: comparison with rest-redistribution thallium 201 imaging.

    Science.gov (United States)

    Iskandrian, A S; Powers, J; Cave, V; Wasserleben, V; Cassell, D; Heo, J

    1995-01-01

    This study examined the ability of dynamic 123I-labeled iodophenylpentadecanoic acid (IPPA) imaging to detect myocardial viability in patients with left ventricular (LV) dysfunction caused by coronary artery disease. Serial 180-degree single-photon emission computed tomographic (SPECT) images (five sets, 8 minutes each) were obtained starting 4 minutes after injection of 2 to 6 mCi 123I at rest in 21 patients with LV dysfunction (ejection fraction [EF] 34% +/- 11%). The segmental uptake was compared with that of rest-redistribution 201Tl images (20 segments/study). The number of perfusion defects (reversible and fixed) was similar by IPPA and thallium (11 +/- 5 vs 10 +/- 5 segments/patient; difference not significant). There was agreement between IPPA and thallium for presence or absence (kappa = 0.78 +/- 0.03) and nature (reversible, mild fixed, or severe fixed) of perfusion defects (kappa = 0.54 +/- 0.04). However, there were more reversible IPPA defects than reversible thallium defects (7 +/- 4 vs 3 +/- 4 segments/patient; p = 0.001). In 14 patients the EF (by gated pool imaging) improved after coronary revascularization from 33% +/- 11% to 39% +/- 12% (p = 0.002). The number of reversible IPPA defects was greater in the seven patients who had improvement in EF than in the patients without such improvement (10 +/- 4 vs 5 +/- 4 segments/patient; p = 0.075). 123I-labeled IPPA SPECT imaging is a promising new technique for assessment of viability. Reversible defects predict recovery of LV dysfunction after coronary revascularization.

  8. User-friendly InSAR Data Products: Fast and Simple Timeseries (FAST) Processing

    Science.gov (United States)

    Zebker, H. A.

    2017-12-01

    Interferometric Synthetic Aperture Radar (InSAR) methods provide high resolution maps of surface deformation applicable to many scientific, engineering and management studies. Despite its utility, the specialized skills and computer resources required for InSAR analysis remain as barriers for truly widespread use of the technique. Reduction of radar scenes to maps of temporal deformation evolution requires not only detailed metadata describing the exact radar and surface acquisition geometries, but also a software package that can combine these for the specific scenes of interest. Furthermore, the radar range-Doppler radar coordinate system itself is confusing, so that many users find it hard to incorporate even useful products in their customary analyses. And finally, the sheer data volume needed to represent interferogram time series makes InSAR analysis challenging for many analysis systems. We show here that it is possible to deliver radar data products to users that address all of these difficulties, so that the data acquired by large, modern satellite systems are ready to use in more natural coordinates, without requiring further processing, and in as small volume as possible.

  9. Radionuclide dynamic renal imaging for renal function study in patients with NIDDM

    International Nuclear Information System (INIS)

    Yang Ruiping; Qu Wanying; Gao Wenping

    1996-01-01

    Radionuclide dynamic renal imaging was performed to gain evidence for further treatment and evaluation of prognosis in patients with non-insulin-dependent diabetes mellitus (NIDDM). 99m Tc-DTPA dynamic renal imaging was performed in 137 NIDDM patients and 44 normal controls (NC). Glomerular filtration rate (GFR) and renogram were acquired simultaneously. Renal tubular secretion function was measured with 99m Tc-EC in 126 of the 137 diabetics and 17 NC. GFR decreased in all patients with different duration of NIDDM and the difference was remarkably significance in comparison with NC (t = 7.17∼13.73, P 99m Tc-EC. This study showed that the function of glomerular filtration and tubular secretion were both damaged in all diabetics. Their magnitude was aggravated with the prolongation of the course of disease

  10. The early assessment of avascular necrosis of femur head in dogs by dynamic bone imaging

    International Nuclear Information System (INIS)

    Li Peiyong; Zhang Huan; Zhang Jixian; Zhu Chengmo; Sun Zhengming; Yang Qingming

    1998-01-01

    Avascular necrosis of femoral head (AVN) was induced unilaterally in 10 dogs by frozen. Dynamic bone imaging was performed before, and 1,3,5,7,12,19 and 33 days after operation. The perfusion index of femoral head (FPI) was calculated by the graphical approach of time-activity curves and quantitation of data. Based on histological examination, pathological lesions on 10 dogs could be classified into four stages: edema, hemorrhage, liquidation, and granulation formation with focal fibrosis, etc. Decreased FPI index was found in all lesions of 10 dogs by dynamic bone imaging. Until 19 days after operation, the uptake was reduced compared to the normal side, whereas after 33 days, its uptake was increased. Perfusion index was considered to reveal the blood flow condition in femoral head. It can be used to detect the early stage of AVN and to understand the effects of various modes of therapy

  11. Measurement of brain oxygenation changes using dynamic T1-weighted imaging

    DEFF Research Database (Denmark)

    Haddock, Bryan; Larsson, Henrik B W; Hansen, Adam E

    2013-01-01

    Magnetic resonance imaging (MRI) has proven useful in evaluating oxygenation in several types of tissue and blood. This study evaluates brain tissue oxygenation changes between normoxia and hyperoxia in healthy subjects using dynamic T1 and T2*-weighted imaging sequences. The change in FiO2 induced...... by hyperoxia caused a significant decrease in T1. A model to determine changes in tissue oxygen tension from the T1-weighted MRI signal is presented based on previous findings that T1 is sensitive to oxygen tension whereas T2* is sensitive to blood saturation. The two sequences produce results with different...... regional and temporal dynamics. These differences combined with results from simulations of the T1 signal intensities, indicate an increase in extravascular oxygen tension during hyperoxia. This study concludes that T1 and T2* responses to FiO2 serve as independent biomarkers of oxygen physiology...

  12. Usefulness of 3D-VIBE method in breast dynamic MRI. Imaging parameters and contrasting effects

    International Nuclear Information System (INIS)

    Uchikoshi, Masato; Ueda, Takashi; Nishiki, Shigeo; Satou, Kouichi; Wada, Akihiko; Imaoka, Izumi; Matsuo, Michimasa

    2003-01-01

    MR imaging (MRI) has been reported to be a useful modality to characterize breast tumors and to evaluate disease extent. Contrast-enhanced dynamic MRI, in particular, allows breast lesions to be characterized with high sensitivity and specificity. Our study was designed to develop three-dimensional volumetric interpolated breath-hold examination (3D-VIBE) techniques for the evaluation of breast tumors. First, agarose/Gd-DTPA phantoms with various concentrations of Gd-DTPA were imaged using 3D-VIBE and turbo spin echo (TSE). Second, one of the phantoms was imaged with 3D-VIBE using different flip angles. Finally, water excitation (WE) and a chemical shift-selective (CHESS) pulse were applied to the images. Each image was analyzed for signal intensity, signal-to-noise ratio (1.25*Ms/Mb) (SNR), and contrast ratio [(Ms1-Ms2)/{(Ms1+Ms2)/2}]. The results showed that 3D-VIBE provided better contrast ratios with a linear fit than TSE, although 3D-VIBE showed a lower SNR. To reach the best contrast ratio, the optimized flip angle was found to be 30 deg for contrast-enhanced dynamic study. Both WE and CHESS pulses were reliable for obtaining fat- suppressed images. In conclusion, the 3D-VIBE technique can image the entire breast area with high resolution and provide better contrast than TSE. Our phantom study suggests that optimized 3D-VIBE may be useful for the assessment of breast tumors. (author)

  13. Design of a dynamic biofilm imaging cell for white-light interferometric microscopy

    Science.gov (United States)

    Larimer, Curtis; Brann, Michelle; Suter, Jonathan D.; Addleman, R. Shane

    2017-11-01

    In microbiology research, there is a strong need for next-generation imaging and sensing instrumentation that will enable minimally invasive and label-free investigation of soft, hydrated structures, such as in bacterial biofilms. White-light interferometry (WLI) can provide high-resolution images of surface topology without the use of fluorescent labels but is not typically used to image biofilms because there is insufficient refractive index contrast to induce reflection from the biofilm's interface. The soft structure and water-like bulk properties of hydrated biofilms make them difficult to characterize in situ, especially in a nondestructive manner. We build on our prior description of static biofilm imaging and describe the design of a dynamic growth flow cell that enables monitoring of the thickness and topology of live biofilms over time using a WLI microscope. The microfluidic system is designed to grow biofilms in dynamic conditions and to create a reflective interface on the surface while minimizing disruption of fragile structures. The imaging cell was also designed to accommodate limitations imposed by the depth of focus of the microscope's objective lens. Example images of live biofilm samples are shown to illustrate the ability of the flow cell and WLI instrument to (1) support bacterial growth and biofilm development, (2) image biofilm structure that reflects growth in flow conditions, and (3) monitor biofilm development over time nondestructively. In future work, the apparatus described here will enable surface metrology measurements (roughness, surface area, etc.) of biofilms and may be used to observe changes in biofilm structure in response to changes in environmental conditions (e.g., flow velocity, availability of nutrients, and presence of biocides). This development will open opportunities for the use of WLI in bioimaging.

  14. Molecular imaging of in vivo redox dynamics using magnetic resonance system

    International Nuclear Information System (INIS)

    Utsumi, Hideo; Yasukawa, Keiji

    2008-01-01

    Homeostatic failure through redox systems in vivo results in abnormality in mitochondrial function, protein expression and metabolism leading to many diseases like lifestyle related ones and cancer. It is therefore important to see redox dynamics for early prevention of the diseases. This paper describes development of machines for electron spin resonance (ESR) imaging of the redox state, for Overhauser Effect MRI (OMRI), application of nitroxyl-probes and state of redox project by authors. They have developed the ESR equipments hitherto, including the latest 300 MHz one, with which images of a mouse given carbamoyl-PROXYL probe are obtained and fused with MRI images for anatomical positioning: resonator for both ESR and MRI coils has been developed for animal images. Philips OMRI machine has been able to give separate images of reduction and oxidation in animals given appropriate probe compounds, which lead to molecular imaging of redox using such probes as 14 N- and 15 N-nitroxyl radicals with different membrane permeability. Application of nitroxyl-radicals like hydroxyl-TEMPO has made it possible for the animal diseases caused by oxidative stress to be analyzed by ESR/spin probe method, and derivatization of the probe results in detection of its distribution in various cell and body areas even in nanometer-space. Authors' project concerns the development of the processing system of redox dynamics/OMRI-integrated images, of better probe complexes and application of these to actual model animals. The techniques are thought to be important in the fields of medicare and new drug development in future. (R.T.)

  15. Efficacy of double arterial phase dynamic magnetic resonance imaging with the sensitivity encoding technique versus dynamic multidetector-row helical computed tomography for detecting hypervascular hepatocellular carcinoma

    International Nuclear Information System (INIS)

    Kumano, Seishi; Okada, Masahiro; Murakami, Takamichi; Uemura, Masahiko; Haraikawa, Toyoaki; Hirata, Masaaki; Kikuchi, Keiichi; Mochizuki, Teruhito; Kim, Tonsok

    2009-01-01

    The aim of this study was to evaluate the efficacy of double arterial phase dynamic magnetic resonance imaging (MRI) with the sensitivity encoding technique (SENSE dynamic MRI) for detection of hypervascular hepatocellular carcinoma (HCC) in comparison with double arterial phase dynamic multidetector-row helical computed tomography (dynamic MDCT). A total of 28 patients with 66 hypervascular HCCs underwent both double arterial SENSE dynamic MRI and dynamic MDCT. The diagnosis of HCC was based on surgical resection (n=7), biopsy (n=10), or a combination of CT during arterial portography (CTAP), CT during hepatic arteriography (CTA), and/or the 6-month follow-up CT (n=49). Based on alternative-free response receiving operating characteristic (ROC) analysis, the diagnostic performance for detecting HCC was compared between double arterial phase SENSE dynamic MRI and double arterial phase dynamic MDCT. The mean sensitivity, positive predictive value, and mean A Z values for hypervascular HCCs were 72%, 80%, and 0.79, respectively, for SENSE dynamic MRI and 66%, 92%, and 0.78, respectively, for dynamic MDCT. The mean sensitivity for double arterial phase SENSE dynamic MRI was higher than that for double arterial phase dynamic MDCT, but the difference was not statistically significant. Double arterial phase SENSE dynamic MRI is as valuable as double arterial phase dynamic MDCT for detecting hypervascular HCCs. (author)

  16. Dynamic PET image reconstruction integrating temporal regularization associated with respiratory motion correction for applications in oncology

    Science.gov (United States)

    Merlin, Thibaut; Visvikis, Dimitris; Fernandez, Philippe; Lamare, Frédéric

    2018-02-01

    Respiratory motion reduces both the qualitative and quantitative accuracy of PET images in oncology. This impact is more significant for quantitative applications based on kinetic modeling, where dynamic acquisitions are associated with limited statistics due to the necessity of enhanced temporal resolution. The aim of this study is to address these drawbacks, by combining a respiratory motion correction approach with temporal regularization in a unique reconstruction algorithm for dynamic PET imaging. Elastic transformation parameters for the motion correction are estimated from the non-attenuation-corrected PET images. The derived displacement matrices are subsequently used in a list-mode based OSEM reconstruction algorithm integrating a temporal regularization between the 3D dynamic PET frames, based on temporal basis functions. These functions are simultaneously estimated at each iteration, along with their relative coefficients for each image voxel. Quantitative evaluation has been performed using dynamic FDG PET/CT acquisitions of lung cancer patients acquired on a GE DRX system. The performance of the proposed method is compared with that of a standard multi-frame OSEM reconstruction algorithm. The proposed method achieved substantial improvements in terms of noise reduction while accounting for loss of contrast due to respiratory motion. Results on simulated data showed that the proposed 4D algorithms led to bias reduction values up to 40% in both tumor and blood regions for similar standard deviation levels, in comparison with a standard 3D reconstruction. Patlak parameter estimations on reconstructed images with the proposed reconstruction methods resulted in 30% and 40% bias reduction in the tumor and lung region respectively for the Patlak slope, and a 30% bias reduction for the intercept in the tumor region (a similar Patlak intercept was achieved in the lung area). Incorporation of the respiratory motion correction using an elastic model along with a

  17. Non-parametric Bayesian models of response function in dynamic image sequences

    Czech Academy of Sciences Publication Activity Database

    Tichý, Ondřej; Šmídl, Václav

    2016-01-01

    Roč. 151, č. 1 (2016), s. 90-100 ISSN 1077-3142 R&D Projects: GA ČR GA13-29225S Institutional support: RVO:67985556 Keywords : Response function * Blind source separation * Dynamic medical imaging * Probabilistic models * Bayesian methods Subject RIV: BB - Applied Statistics, Operational Research Impact factor: 2.498, year: 2016 http://library.utia.cas.cz/separaty/2016/AS/tichy-0456983.pdf

  18. Fat-suppressed dynamic MR imaging for the postoperative evaluation of pituitary adenomas

    International Nuclear Information System (INIS)

    Akada, Kiyohiro

    2000-01-01

    The usefulness of the early post operative evaluation of pituitary adenomas with fat-suppressed MR imaging was studied. Thirty patients with pituitary adenoma, who underwent trans-sphenoidal surgery were analyzed. These include 22 with macroadenoma (3 recurrent cases) and 8 with microadeno