Science.gov

Sample records for imaging spatial resolution

  1. Polarization imaging with enhanced spatial resolution

    NASA Astrophysics Data System (ADS)

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

    2015-03-01

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

  2. Bioelasticity imaging:II. Spatial resolution

    NASA Astrophysics Data System (ADS)

    Cook, Larry T.; Zhu, Yanning; Hall, Timothy J.; Insana, Michael F.

    2000-04-01

    The large elasticity contrast possible with strain imaging promises new diagnostic information to augment x-ray, MRI, and ultrasound for the detection of tumors in soft tissue. In the past, we described the design of an elastographic system using the Fourier crosstalk concept introduced by Barrett and Gifford. The diagonal of the crosstalk matrix is related to the pre-sampled modulation transfer function (MTF) of the strain image. Another approach to measuring the spatial resolution of an elasticity image employs a linear frequency- modulated (chirp) strain pattern imposed upon a simulated ultrasonic echo field to study the strain modulation over a range of spatial frequencies in the image. In experiments, high contrast inclusions positioned at varying separations were imaged to apply the Rayleigh criterion for resolution measurement. We measured MTF curves that fell to 0.2 at a spatial frequency of 0.5 mm-1 to 1 mm-1 under realistic conditions. The spatial resolution for ultrasonic strain imaging strongly depends on the transducer properties and deformation patterns applied to the object. Experiments with tissue-like phantoms mimicking the properties of early breast cancer show that 2 mm spheres three times stiffer than the background can be readily resolved. Thus, the potential for using elasticity imaging to detect early breast cancers is excellent.

  3. High spatial resolution restoration of IRAS images

    NASA Technical Reports Server (NTRS)

    Grasdalen, Gary L.; Inguva, R.; Dyck, H. Melvin; Canterna, R.; Hackwell, John A.

    1990-01-01

    A general technique to improve the spatial resolution of the IRAS AO data was developed at The Aerospace Corporation using the Maximum Entropy algorithm of Skilling and Gull. The technique has been applied to a variety of fields and several individual AO MACROS. With this general technique, resolutions of 15 arcsec were achieved in 12 and 25 micron images and 30 arcsec in 60 and 100 micron images. Results on galactic plane fields show that both photometric and positional accuracy achieved in the general IRAS survey are also achieved in the reconstructed images.

  4. Effects of spatial resolution ratio in image fusion

    USGS Publications Warehouse

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

    2008-01-01

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

  5. High Spatial Resolution Commercial Satellite Imaging Product Characterization

    NASA Technical Reports Server (NTRS)

    Ryan, Robert E.; Pagnutti, Mary; Blonski, Slawomir; Ross, Kenton W.; Stnaley, Thomas

    2005-01-01

    NASA Stennis Space Center's Remote Sensing group has been characterizing privately owned high spatial resolution multispectral imaging systems, such as IKONOS, QuickBird, and OrbView-3. Natural and man made targets were used for spatial resolution, radiometric, and geopositional characterizations. Higher spatial resolution also presents significant adjacency effects for accurate reliable radiometry.

  6. Super Spatial Resolution (SSR) method for scintigraphic imaging

    NASA Astrophysics Data System (ADS)

    Trinci, G.; Massari, R.; Scandellari, M.; Scopinaro, F.; Soluri, A.

    2011-01-01

    This work describes an innovative patented Super Spatial Resolution (SSR) method applied to scintigraphic devices. The aim of Super Resolution (SR) techniques is to enhance the resolution of an imaging system, using information from several images. SR reconstruction may be considered as a second generation problem of Image Restoration. It combines several slightly different Low Resolution (LR) images to obtain a High Resolution (HR) image. SR techniques are, widely, described in scientific literature mainly for applications in video communication, object recognition and image compression. In this paper we focus to apply the SR task to the scintigraphic imaging. Specifically, it is described as a patented method that uses a High Resolution Scintigraphic Camera (HRSC) to collect and process a set of scintigraphic images, in view of obtaining a very high resolution image. The HRSC device, which is currently used in Medical Imaging, is based on a parallel square holes collimator and on a Hamamatsu H8500 Position Sensitive Photomultiplier Tubes (PSPMT). The SSR method is applied to the synthetic images of three different phantoms, to verify the effective spatial resolution values. The results confirm that it is possible to achieve optimal spatial resolution values at different depths, useful in small object and small animal imaging. Our study confirms the feasibility of a very high resolution system in scintigraphic imaging and the possibility to have gamma cameras using the SSR method, to perform clinical applications on patients.

  7. IKONOS Spatial Resolution and Image Interpretability Characterization

    NASA Technical Reports Server (NTRS)

    Ryan, Robert; Baldridge, Braxton; Schowengerdt, Robert A.; Choi, Taeyoung; Helder, Dennis L.; Blonski, Slawomir

    2003-01-01

    This paper contains research from five individual projects to characterize the spatial performance of the IKONOS commercial imaging sensor. The end result of the projects is determination of the spatial image quality of IKONOS data prodicts in terms of the National Imagery Interpretability Rating Scale (NIIRS), the system Modulation Transfer Function (MTF), the system stability over the first year, the characteristics of the Space Imaging MTF Compensation (MTFC) procedure, and the application-specific capabilities of IKONOS imagery. Both panchromatic and multispectral imagery were evaluated. Major conclusions of this work are that the system was stable im imaging performance during the first year of operation, tha its MTF meets the specification for the NASA Scientific Data Purchase program, that the initial MTFC processing appears to be transposed in the in-track and the cross-track directions, that the MTFC results in a noise amplification of 2x to 4x in addition to sharpening the imagery, and that IKONOS panchromatic imagery achieves an average NIIRS rating of 4.5.

  8. Sub-pixel spatial resolution wavefront phase imaging

    NASA Technical Reports Server (NTRS)

    Stahl, H. Philip (Inventor); Mooney, James T. (Inventor)

    2012-01-01

    A phase imaging method for an optical wavefront acquires a plurality of phase images of the optical wavefront using a phase imager. Each phase image is unique and is shifted with respect to another of the phase images by a known/controlled amount that is less than the size of the phase imager's pixels. The phase images are then combined to generate a single high-spatial resolution phase image of the optical wavefront.

  9. Spatial Resolution Characterization for AWiFS Multispectral Images

    NASA Technical Reports Server (NTRS)

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

    2007-01-01

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

  10. Lidar imaging with on-the-fly adaptable spatial resolution

    NASA Astrophysics Data System (ADS)

    Riu, J.; Royo, S.

    2013-10-01

    We present our work in the design and construction of a novel type of lidar device capable of measuring 3D range images with an spatial resolution which can be reconfigured through an on-the-fly configuration approach, adjustable by software and on the image area, and which can reach the 2Mpixel value. A double-patented novel concept of scanning system enables to change dynamically the image resolution depending on external information provided by the image captured in a previous cycle or on other sensors like greyscale or hyperspectral 2D imagers. A prototype of an imaging lidar system which can modify its spatial resolution on demand from one image to the next according to the target nature and state has been developed, and indoor and outdoor sample images showing its performance are presented. Applications in object detection, tracking and identification through a real-time adaptable scanning system for each situation and target behaviour are currently being pursued in different areas.

  11. Imaging metals in biology: balancing sensitivity, selectivity and spatial resolution.

    PubMed

    Hare, Dominic J; New, Elizabeth J; de Jonge, Martin D; McColl, Gawain

    2015-10-01

    Metal biochemistry drives a diverse range of cellular processes associated with development, health and disease. Determining metal distribution, concentration and flux defines our understanding of these fundamental processes. A comprehensive analysis of biological systems requires a balance of analytical techniques that inform on metal quantity (sensitivity), chemical state (selectivity) and location (spatial resolution) with a high degree of certainty. A number of approaches are available for imaging metals from whole tissues down to subcellular organelles, as well as mapping metal turnover, protein association and redox state within these structures. Technological advances in micro- and nano-scale imaging are striving to achieve multi-dimensional and in vivo measures of metals while maintaining the native biochemical environment and physiological state. This Tutorial Review discusses state-of-the-art imaging technology as a guide to obtaining novel insight into the biology of metals, with sensitivity, selectivity and spatial resolution in focus. PMID:26505053

  12. Variable resolution imaging fiber probe using digital spatial light modulator

    NASA Astrophysics Data System (ADS)

    Shinde, Anant; Perinchery, Sandeep M.; Vadakke Matham, Murukeshan

    2015-07-01

    Flexible fiber optic imaging systems including fiber optic confocal probes have found tremendous significance in the recent past for its applications in high resolution imaging. However, motorized stage is required for scanning the sample or tip of the fiber in fiber based confocal probes. In this context, we propose a fiber probe confocal system using digital spatial light modulator devoid of using a mechanical scanning stage. Each fiberlet in the image fiber acts not only as a light conduit but also as a confocal pinhole. The paper also introduces the variation in the contrast by varying the number of illuminated fiberlets which effectively implies variation in the effective pinhole size. This approach has enabled the probe to act as an imaging unit with resolution that can be controlled and varied from a wide-field to a confocal.

  13. Spatial super-resolution in code aperture spectral imaging

    NASA Astrophysics Data System (ADS)

    Arguello, Henry; Rueda, Hoover F.; Arce, Gonzalo R.

    2012-06-01

    The Code Aperture Snapshot Spectral Imaging system (CASSI) senses the spectral information of a scene using the underlying concepts of compressive sensing (CS). The random projections in CASSI are localized such that each measurement contains spectral information only from a small spatial region of the data cube. The goal of this paper is to translate high-resolution hyperspectral scenes into compressed signals measured by a low-resolution detector. Spatial super-resolution is attained as an inverse problem from a set of low-resolution coded measurements. The proposed system not only offers significant savings in size, weight and power, but also in cost as low resolution detectors can be used. The proposed system can be efficiently exploited in the IR region where the cost of detectors increases rapidly with resolution. The simulations of the proposed system show an improvement of up to 4 dB in PSNR. Results also show that the PSNR of the reconstructed data cubes approach the PSNR of the reconstructed data cubes attained with high-resolution detectors, at the cost of using additional measurements.

  14. Photoacoustic lymphatic imaging with high spatial-temporal resolution

    NASA Astrophysics Data System (ADS)

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

    2014-11-01

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

  15. Improving PET spatial resolution and detectability for prostate cancer imaging

    NASA Astrophysics Data System (ADS)

    Bal, H.; Guerin, L.; Casey, M. E.; Conti, M.; Eriksson, L.; Michel, C.; Fanti, S.; Pettinato, C.; Adler, S.; Choyke, P.

    2014-08-01

    Prostate cancer, one of the most common forms of cancer among men, can benefit from recent improvements in positron emission tomography (PET) technology. In particular, better spatial resolution, lower noise and higher detectability of small lesions could be greatly beneficial for early diagnosis and could provide a strong support for guiding biopsy and surgery. In this article, the impact of improved PET instrumentation with superior spatial resolution and high sensitivity are discussed, together with the latest development in PET technology: resolution recovery and time-of-flight reconstruction. Using simulated cancer lesions, inserted in clinical PET images obtained with conventional protocols, we show that visual identification of the lesions and detectability via numerical observers can already be improved using state of the art PET reconstruction methods. This was achieved using both resolution recovery and time-of-flight reconstruction, and a high resolution image with 2 mm pixel size. Channelized Hotelling numerical observers showed an increase in the area under the LROC curve from 0.52 to 0.58. In addition, a relationship between the simulated input activity and the area under the LROC curve showed that the minimum detectable activity was reduced by more than 23%.

  16. Spatial Resolution Requirements for MODIS-N. [Polar Platform Moderate Resolution Imaging Spectrometer (MODIS)

    NASA Technical Reports Server (NTRS)

    Townshend, J. R. G.; Justice, C. O.; Markham, B. L.; Briggs, S. A.

    1988-01-01

    An empirical investigation of the required spatial resolution for MODIS-N is outlined. It is based on 5 LANDSAT multispectral scanner system images of the normalized difference vegetation index degraded to resolutions between 250 m and 4000 m. Pairs of images from different dates were registered and difference images were generated. Fourier analysis indicates that resolutions finer than 1 km are highly desirable for change detection. A sensor with a resolution of 500 m is recommended as providing the best compromise between detail of changes detected and the size of the resultant data volume, but other options are also suggested.

  17. Spatially resolved and observer-free experimental quantification of spatial resolution in tomographic images

    SciTech Connect

    Tsekenis, S. A.; McCann, H.; Tait, N.

    2015-03-15

    We present a novel framework and experimental method for the quantification of spatial resolution of a tomography system. The framework adopts the “black box” view of an imaging system, considering only its input and output. The tomography system is locally stimulated with a step input, viz., a sharp edge. The output, viz., the reconstructed images, is analysed by Fourier decomposition of their spatial frequency components, and the local limiting spatial resolution is determined using a cut-off threshold. At no point is an observer involved in the process. The framework also includes a means of translating the quantification region in the imaging space, thus creating a spatially resolved map of objectively quantified spatial resolution. As a case-study, the framework is experimentally applied using a gaseous propane phantom measured by a well-established chemical species tomography system. A spatial resolution map consisting of 28 regions is produced. In isolated regions, the indicated performance is 4-times better than that suggested in the literature and varies by 57% across the imaging space. A mechanism based on adjacent but non-interacting beams is hypothesised to explain the observed behaviour. The mechanism suggests that, as also independently concluded by other methods, a geometrically regular beam array maintains maximum objectivity in reconstructions. We believe that the proposed framework, methodology, and findings will be of value in the design and performance evaluation of tomographic imaging arrays and systems.

  18. Spatial Resolution Characterization for AWiFS Multispectral Images

    NASA Technical Reports Server (NTRS)

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

    2006-01-01

    Within the framework of the Joint Agency Commercial Imagery Evaluation program, the National Aeronautics and Space Administration, the National Geospatial-Intelligence Agency, and the U.S. Geological Survey cooperate in the characterization of high-to-moderate-resolution commercial imagery of mutual interest. One of the systems involved in this effort is the Advanced Wide Field Sensor (AWiFS) onboard the Indian Remote Sensing (IRS) Reourcesat-1 satellite, IRS-P6. Spatial resolution of the AWiFS multispectral images was characterized by estimating the value of the system Modulation Transfer Function (MTF) at the Nyquist spatial frequency. The Nyquist frequency is defined as half the sampling frequency, and the sampling frequency is equal to the inverse of the ground sample distance. The MTF was calculated as a ratio of the Fourier transform of a profile across an AWiFS image of the Lake Pontchartrain Causeway Bridge and the Fourier transform of a profile across an idealized model of the bridge for each spectral band evaluated. The mean MTF value for the AWiFS imagery evaluated was estimated to be 0.1.

  19. Advanced Remote-Sensing Imaging Emission Spectrometer (ARIES): AIRS Spectral Resolution with MODIS Spatial Resolution

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Aumann, Hartmut H.; OCallaghan, Fred

    2006-01-01

    The Advanced Remote-sensing Imaging Emission Spectrometer (ARIES) will measure a wide range of earth quantities fundamental to the study of global climate change. It will build upon the success of the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Atmospheric Infrared Sounder (AIRS) instruments currently flying on the EOS Aqua Spacecraft. Both instruments are facility instruments for NASA providing data to thousands of scientists investigating land, ocean and atmospheric Earth System processes. ARIES will meet all the requirements of AIRS and MODIS in a single compact instrument, while providing the next-generation capability of improved spatial resolution for AIRS and improved spectral resolution for MODIS.

  20. 3D spatial resolution and spectral resolution of interferometric 3D imaging spectrometry.

    PubMed

    Obara, Masaki; Yoshimori, Kyu

    2016-04-01

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

  1. Spatially Regularized Compressed Sensing for High Angular Resolution Diffusion Imaging

    PubMed Central

    Rathi, Yogesh; Dolui, Sudipto

    2013-01-01

    Despite the relative recency of its inception, the theory of compressive sampling (aka compressed sensing) (CS) has already revolutionized multiple areas of applied sciences, a particularly important instance of which is medical imaging. Specifically, the theory has provided a different perspective on the important problem of optimal sampling in magnetic resonance imaging (MRI), with an ever-increasing body of works reporting stable and accurate reconstruction of MRI scans from the number of spectral measurements which would have been deemed unacceptably small as recently as five years ago. In this paper, the theory of CS is employed to palliate the problem of long acquisition times, which is known to be a major impediment to the clinical application of high angular resolution diffusion imaging (HARDI). Specifically, we demonstrate that a substantial reduction in data acquisition times is possible through minimization of the number of diffusion encoding gradients required for reliable reconstruction of HARDI scans. The success of such a minimization is primarily due to the availability of spherical ridgelet transformation, which excels in sparsifying HARDI signals. What makes the resulting reconstruction procedure even more accurate is a combination of the sparsity constraints in the diffusion domain with additional constraints imposed on the estimated diffusion field in the spatial domain. Accordingly, the present paper describes an original way to combine the diffusion-and spatial-domain constraints to achieve a maximal reduction in the number of diffusion measurements, while sacrificing little in terms of reconstruction accuracy. Finally, details are provided on an efficient numerical scheme which can be used to solve the aforementioned reconstruction problem by means of standard and readily available estimation tools. The paper is concluded with experimental results which support the practical value of the proposed reconstruction methodology. PMID:21536524

  2. Super Resolution from Hyperview Image Stack by Spatial Multiplexing

    NASA Astrophysics Data System (ADS)

    Grasnick, Armin

    2016-09-01

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

  3. A new reduced-reference metric for measuring spatial resolution enhanced images

    NASA Astrophysics Data System (ADS)

    Qian, Shen-En; Chen, Guangyi

    2012-10-01

    Assessment of image quality is critical for many image processing algorithms, such as image acquisition, compression, restoration, enhancement, and reproduction. In general, image quality assessment algorithms are classified into three categories: full-reference (FR), reduced-reference (RR), and no-reference (NR) algorithms. The design of NR metrics is extremely difficult and little progress has been made. FR metrics are easier to design and the majority of image quality assessment algorithms are of this type. A FR metric requires the reference image and the test image to have the same size. This may not the case in real life of image processing. In spatial resolution enhancement of hyperspectral images, such as pan-sharpening, the size of the enhanced images is larger than that of the original image. Thus, the FR metric cannot be used. A common approach in practice is to first down-sample an original image to a low resolution image, then to spatially enhance the down-sampled low resolution image using a subject enhancement technique. In this way, the original image and the enhanced image have the same size and the FR metric can be applied to them. However, this common approach can never directly assess the image quality of the spatially enhanced image that is produced directly from the original image. In this paper, a new RR metric was proposed for measuring the visual fidelity of an image with higher spatial resolution. It does not require the sizes of the reference image and the test image to be the same. The iterative back projection (IBP) technique was chosen to enhance the spatial resolution of an image. Experimental results showed that the proposed RR metrics work well for measuring the visual quality of spatial resolution enhanced hyperspectral images. They are consistent with the corresponding FR metrics.

  4. Change of spatial information under rescaling: A case study using multi-resolution image series

    NASA Astrophysics Data System (ADS)

    Chen, Weirong; Henebry, Geoffrey M.

    Spatial structure in imagery depends on a complicated interaction between the observational regime and the types and arrangements of entities within the scene that the image portrays. Although block averaging of pixels has commonly been used to simulate coarser resolution imagery, relatively little attention has been focused on the effects of simple rescaling on spatial structure and the explanation and a possible solution to the problem. Yet, if there are significant differences in spatial variance between rescaled and observed images, it may affect the reliability of retrieved biogeophysical quantities. To investigate these issues, a nested series of high spatial resolution digital imagery was collected at a research site in eastern Nebraska in 2001. An airborne Kodak DCS420IR camera acquired imagery at three altitudes, yielding nominal spatial resolutions ranging from 0.187 m to 1 m. The red and near infrared (NIR) bands of the co-registered image series were normalized using pseudo-invariant features, and the normalized difference vegetation index (NDVI) was calculated. Plots of grain sorghum planted in orthogonal crop row orientations were extracted from the image series. The finest spatial resolution data were then rescaled by averaging blocks of pixels to produce a rescaled image series that closely matched the spatial resolution of the observed image series. Spatial structures of the observed and rescaled image series were characterized using semivariogram analysis. Results for NDVI and its component bands show, as expected, that decreasing spatial resolution leads to decreasing spatial variability and increasing spatial dependence. However, compared to the observed data, the rescaled images contain more persistent spatial structure that exhibits limited variation in both spatial dependence and spatial heterogeneity. Rescaling via simple block averaging fails to consider the effect of scene object shape and extent on spatial information. As the features

  5. A condition on the spatial resolution of IR collimators for testing of thermal imaging systems

    NASA Astrophysics Data System (ADS)

    Chrzanowski, Krzysztof; Lee, Hee Chul; Wrona, Wieslaw

    2000-05-01

    A precise condition on the spatial resolution of the IR collimator for testing thermal imaging systems is presented. The condition can be used even if only the spatial resolution of the IR collimator and that of the system under test, measured using popular definitions, are known. It is shown that when the condition is fulfilled, the thermal image degradation caused by the IR collimator is negligible.

  6. Interaction of image noise, spatial resolution, and low contrast fine detail preservation in digital image processing

    NASA Astrophysics Data System (ADS)

    Artmann, Uwe; Wueller, Dietmar

    2009-01-01

    We present a method to improve the validity of noise and resolution measurements on digital cameras. If non-linear adaptive noise reduction is part of the signal processing in the camera, the measurement results for image noise and spatial resolution can be good, while the image quality is low due to the loss of fine details and a watercolor like appearance of the image. To improve the correlation between objective measurement and subjective image quality we propose to supplement the standard test methods with an additional measurement of the texture preserving capabilities of the camera. The proposed method uses a test target showing white Gaussian noise. The camera under test reproduces this target and the image is analyzed. We propose to use the kurtosis of the derivative of the image as a metric for the texture preservation of the camera. Kurtosis is a statistical measure for the closeness of a distribution compared to the Gaussian distribution. It can be shown, that the distribution of digital values in the derivative of the image showing the chart becomes the more leptokurtic (increased kurtosis) the stronger the noise reduction has an impact on the image.

  7. A High Spatial Resolution CT Scanner for Small Animal Imaging

    NASA Astrophysics Data System (ADS)

    Cicalini, E.; Baldazzi, G.; Belcari, N.; Del Guerra, A.; Gombia, M.; Motta, A.; Panetta, D.

    2006-01-01

    We have built a micro-CT system that will be integrated with a small animal PET scanner. The components are: an X-ray source with a peak voltage of up to 60 kV, a power of 10 W and a focal spot size of 30 μm; a CCD coupled to CsI(Tl) scintillator, subdivided into 128×3072 square pixels, each with a size of 48 μm; stepping motors for the sample roto-translation; a PCI acquisition board; electronic boards to control and read-out the CCD. A program in Lab VIEW controls the data acquisition. Reconstruction algorithms have been implemented for fan-beam and cone-beam configurations. Images of a bar pattern have been acquired to evaluate the detector performance: the CTF curve has been extracted from the data, obtaining a value of 10 % at 5 lp/mm and about 3 % at 10 lp/mm. Tomographic acquisitions have been performed with a test phantom consisting of a Plexiglas cylinder, 3 cm in diameter, with holes ranging from 3 mm down to 0.6 mm in diameter, filled with different materials. The contrast resolution has been extracted from the reconstructed images: a value of 6 % (in water) for a cubic voxel size of 80 μm has been obtained.

  8. Standard Reticle Slide To Objectively Evaluate Spatial Resolution and Instrument Performance in Imaging Mass Spectrometry.

    PubMed

    Zubair, Faizan; Prentice, Boone M; Norris, Jeremy L; Laibinis, Paul E; Caprioli, Richard M

    2016-07-19

    Spatial resolution is a key parameter in imaging mass spectrometry (IMS). Aside from being a primary determinant in overall image quality, spatial resolution has important consequences on the acquisition time of the IMS experiment and the resulting file size. Hardware and software modifications during instrumentation development can dramatically affect the spatial resolution achievable using a given imaging mass spectrometer. As such, an accurate and objective method to determine the working spatial resolution is needed to guide instrument development and ensure quality IMS results. We have used lithographic and self-assembly techniques to fabricate a pattern of crystal violet as a standard reticle slide for assessing spatial resolution in matrix-assisted laser desorption/ionization (MALDI) IMS experiments. The reticle is used to evaluate spatial resolution under user-defined instrumental conditions. Edgespread analysis measures the beam diameter for a Gaussian profile and line scans measure an "effective" spatial resolution that is a convolution of beam optics and sampling frequency. The patterned crystal violet reticle was also used to diagnose issues with IMS instrumentation such as intermittent losses of pixel data. PMID:27299987

  9. Research on the affect of differential-images technique to the resolution of infrared spatial camera

    NASA Astrophysics Data System (ADS)

    Jin, Guang; An, Yuan; Qi, Yingchun; Hu, Fusheng

    2007-12-01

    The optical system of infrared spatial camera adopts bigger relative aperture and bigger pixel size on focal plane element. These make the system have bulky volume and low resolution. The potential of the optical systems can not be exerted adequately. So, one method for improving resolution of infrared spatial camera based on multi-frame difference-images is introduced in the dissertation. The method uses more than one detectors to acquire several difference images, and then reconstructs a new high-resolution image from these images through the relationship of pixel grey value. The technique of difference-images that uses more than two detectors is researched, and it can improve the resolution 2.5 times in theory. The relationship of pixel grey value between low-resolution difference-images and high-resolution image is found by analyzing the energy of CCD sampling, a general relationship between the enhanced times of the resolution of the detected figure with differential method and the least count of CCD that will be used to detect figure is given. Based on the research of theory, the implementation process of utilizing difference-images technique to improve the resolution of the figure was simulated used Matlab software by taking a personality image as the object, and the software can output the result as an image. The result gotten from the works we have finished proves that the technique is available in high-resolution image reconstruction. The resolution of infrared spatial camera can be improved evidently when holding the size of optical structure or using big size detector by applying for difference image technique. So the technique has a high value in optical remote fields.

  10. Resolution and Brightness Characteristics of Short-Lag Spatial Coherence (SLSC) Images

    PubMed Central

    Lediju Bell, Muyinatu A.; Dahl, Jeremy J.; Trahey, Gregg E.

    2016-01-01

    We previously described a novel beamforming method that images the spatial correlation of an echo wave field with demonstrated applications to clutter reduction in high-noise environments. In this paper, several characteristics of the resolution and brightness of short-lag spatial coherence (SLSC) images formed by this method are compared with B-mode images formed by conventional delay-and-sum beamforming methods. Point target widths were measured to estimate resolution, the autocorrelation of image texture was measured to estimate texture size, and the contrast (i.e., brightness ratio) of clinically relevant targets was assessed. SLSC images demonstrate improved resolution and contrast with increasing values of channel noise and clutter, whereas B-mode resolution was degraded in the presence of high noise (i.e., > −12 dB channel noise-to-signal ratios) and high clutter magnitudes (i.e., > −21 dB relative to point target magnitude). Lateral resolution in SLSC images was improved with increasing lag value, whereas axial resolution was degraded with increasing correlation kernel length. The texture size of SLSC images was smaller than that of matched B-mode images. Results demonstrate that the resolution and contrast of coherence-based images depend on a range of parameters, but are generally superior to those of matched B-mode images under challenging imaging conditions. PMID:26168173

  11. HIGH SPATIAL RESOLUTION IMAGING OF THERMAL EMISSION FROM DEBRIS DISKS

    SciTech Connect

    Moerchen, Margaret M.; Telesco, Charles M.; Packham, Christopher

    2010-11-10

    We have obtained subarcsecond mid-IR images of a sample of debris disks within 100 pc. For our sample of 19 A-type debris disk candidates chosen for their IR excess, we have resolved, for the first time, five sources plus the previously resolved disk around HD 141569. Two other sources in our sample have been ruled out as debris disks since the time of sample selection. Three of the six resolved sources have inferred radii of 1-4 AU (HD 38678, HD 71155, and HD 181869), and one source has an inferred radius {approx}10-30 AU (HD 141569). Among the resolved sources with detections of excess IR emission, HD 71155 appears to be comparable in size (r {approx} 2 AU) to the solar system's asteroid belt, thus joining {zeta} Lep (HD 38678, reported previously) to comprise the only two resolved sources of that class. Two additional sources (HD 95418 and HD 139006) show spatial extents that imply disk radii of {approx}1-3 AU, although the excess IR fluxes are not formally detected with better than 2{sigma} significance. For the unresolved sources, the upper limits on the maximum radii of mid-IR disk emission are in the range {approx}1-20 AU, four of which are comparable in radius to the asteroid belt. We have compared the global color temperatures of the dust to that expected for the dust in radiative equilibrium at the distances corresponding to the observed sizes or limits on the sizes. In most cases, the temperatures estimated via these two methods are comparable, and therefore, we see a generally consistent picture of the inferred morphology and the global mid-IR emission. Finally, while our sample size is not statistically significant, we note that the older sources (>200 Myr) host much warmer dust (T {approx}> 400 K) than younger sources (in the tens of Myr).

  12. Atmospheric Correction Prototype Algorithm for High Spatial Resolution Multispectral Earth Observing Imaging Systems

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary

    2006-01-01

    This viewgraph presentation reviews the creation of a prototype algorithm for atmospheric correction using high spatial resolution earth observing imaging systems. The objective of the work was to evaluate accuracy of a prototype algorithm that uses satellite-derived atmospheric products to generate scene reflectance maps for high spatial resolution (HSR) systems. This presentation focused on preliminary results of only the satellite-based atmospheric correction algorithm.

  13. Quantitative metrics for assessment of chemical image quality and spatial resolution

    DOE PAGESBeta

    Kertesz, Vilmos; Cahill, John F.; Van Berkel, Gary J.

    2016-02-28

    Rationale: Currently objective/quantitative descriptions of the quality and spatial resolution of mass spectrometry derived chemical images are not standardized. Development of these standardized metrics is required to objectively describe chemical imaging capabilities of existing and/or new mass spectrometry imaging technologies. Such metrics would allow unbiased judgment of intra-laboratory advancement and/or inter-laboratory comparison for these technologies if used together with standardized surfaces. Methods: We developed two image metrics, viz., chemical image contrast (ChemIC) based on signal-to-noise related statistical measures on chemical image pixels and corrected resolving power factor (cRPF) constructed from statistical analysis of mass-to-charge chronograms across features of interest inmore » an image. These metrics, quantifying chemical image quality and spatial resolution, respectively, were used to evaluate chemical images of a model photoresist patterned surface collected using a laser ablation/liquid vortex capture mass spectrometry imaging system under different instrument operational parameters. Results: The calculated ChemIC and cRPF metrics determined in an unbiased fashion the relative ranking of chemical image quality obtained with the laser ablation/liquid vortex capture mass spectrometry imaging system. These rankings were used to show that both chemical image contrast and spatial resolution deteriorated with increasing surface scan speed, increased lane spacing and decreasing size of surface features. Conclusions: ChemIC and cRPF, respectively, were developed and successfully applied for the objective description of chemical image quality and spatial resolution of chemical images collected from model surfaces using a laser ablation/liquid vortex capture mass spectrometry imaging system.« less

  14. Magnetoacoustic Imaging of Electrical Conductivity of Biological Tissues at a Spatial Resolution Better than 2 mm

    PubMed Central

    Hu, Gang; He, Bin

    2011-01-01

    Magnetoacoustic tomography with magnetic induction (MAT-MI) is an emerging approach for noninvasively imaging electrical impedance properties of biological tissues. The MAT-MI imaging system measures ultrasound waves generated by the Lorentz force, having been induced by magnetic stimulation, which is related to the electrical conductivity distribution in tissue samples. MAT-MI promises to provide fine spatial resolution for biological tissue imaging as compared to ultrasound resolution. In the present study, we first estimated the imaging spatial resolution by calculating the full width at half maximum (FWHM) of the system point spread function (PSF). The actual spatial resolution of our MAT-MI system was experimentally determined to be 1.51 mm by a parallel-line-source phantom with Rayleigh criterion. Reconstructed images made from tissue-mimicking gel phantoms, as well as animal tissue samples, were consistent with the morphological structures of the samples. The electrical conductivity value of the samples was determined directly by a calibrated four-electrode system. It has been demonstrated that MAT-MI is able to image the electrical impedance properties of biological tissues with better than 2 mm spatial resolution. These results suggest the potential of MAT-MI for application to early detection of small-size diseased tissues (e.g. small breast cancer). PMID:21858111

  15. Advanced Remote-sensing Imaging Emission Spectrometer (ARIES): AIRS Spectral Resolution with MODIS Spatial Resolution

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Chahine, Moustafa T.; Aumann, Hartmut H.; OCallaghan, Fred G.; Broberg, Steve E.

    2006-01-01

    This paper describes a space based instrument concept that will provide scientists with data needed to support key ongoing and future Earth System Science investigations. The measurement approach builds on the observations made by AIRS and MODIS and exceeds their capability with improved spatial and spectral resolution. This paper describes the expected products and the instrument concept that can meet those requirements.

  16. Full field spatially-variant image-based resolution modelling reconstruction for the HRRT.

    PubMed

    Angelis, Georgios I; Kotasidis, Fotis A; Matthews, Julian C; Markiewicz, Pawel J; Lionheart, William R; Reader, Andrew J

    2015-03-01

    Accurate characterisation of the scanner's point spread function across the entire field of view (FOV) is crucial in order to account for spatially dependent factors that degrade the resolution of the reconstructed images. The HRRT users' community resolution modelling reconstruction software includes a shift-invariant resolution kernel, which leads to transaxially non-uniform resolution in the reconstructed images. Unlike previous work to date in this field, this work is the first to model the spatially variant resolution across the entire FOV of the HRRT, which is the highest resolution human brain PET scanner in the world. In this paper we developed a spatially variant image-based resolution modelling reconstruction dedicated to the HRRT, using an experimentally measured shift-variant resolution kernel. Previously, the system response was measured and characterised in detail across the entire FOV of the HRRT, using a printed point source array. The newly developed resolution modelling reconstruction was applied on measured phantom, as well as clinical data and was compared against the HRRT users' community resolution modelling reconstruction, which is currently in use. Results demonstrated improvements both in contrast and resolution recovery, particularly for regions close to the edges of the FOV, with almost uniform resolution recovery across the entire transverse FOV. In addition, because the newly measured resolution kernel is slightly broader with wider tails, compared to the deliberately conservative kernel employed in the HRRT users' community software, the reconstructed images appear to have not only improved contrast recovery (up to 20% for small regions), but also better noise characteristics. PMID:25596999

  17. Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

    NASA Astrophysics Data System (ADS)

    Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth; Huang, Xiaojing; Wagner, Ulrich; Rau, Christoph; Yusuf, Mohammed; Robinson, Ian; Kalbfleisch, Sebastian; Li, Li; Bouet, Nathalie; Zhou, Juan; Conley, Ray; Chu, Yong S.

    2016-02-01

    We developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray’s superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioning it.

  18. Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

    DOE PAGESBeta

    Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth R.; Huang, Xiaojing; Wagner, Ulrich; Rau, Christoph; Yusuf, Mohammed; Robinson, Ian K.; Kalbfleisch, Sebastian; Li, Li; et al

    2016-02-05

    Here, we developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray's superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioningmore » it.« less

  19. Multimodality hard-x-ray imaging of a chromosome with nanoscale spatial resolution

    PubMed Central

    Yan, Hanfei; Nazaretski, Evgeny; Lauer, Kenneth; Huang, Xiaojing; Wagner, Ulrich; Rau, Christoph; Yusuf, Mohammed; Robinson, Ian; Kalbfleisch, Sebastian; Li, Li; Bouet, Nathalie; Zhou, Juan; Conley, Ray; Chu, Yong S.

    2016-01-01

    We developed a scanning hard x-ray microscope using a new class of x-ray nano-focusing optic called a multilayer Laue lens and imaged a chromosome with nanoscale spatial resolution. The combination of the hard x-ray’s superior penetration power, high sensitivity to elemental composition, high spatial-resolution and quantitative analysis creates a unique tool with capabilities that other microscopy techniques cannot provide. Using this microscope, we simultaneously obtained absorption-, phase-, and fluorescence-contrast images of Pt-stained human chromosome samples. The high spatial-resolution of the microscope and its multi-modality imaging capabilities enabled us to observe the internal ultra-structures of a thick chromosome without sectioning it. PMID:26846188

  20. Image readout device with electronically variable spatial resolution

    NASA Technical Reports Server (NTRS)

    Benz, H. A. (Inventor)

    1981-01-01

    An invention relating to the use of a standing acoustic wave charge storage device as an image readout device is described. A frequency f sub 1 was applied to the storage transfer device to create a traveling electric field in the device in one direction along a straight line. A second frequency f sub 2 was applied to the charge transfer device to create a traveling electric field opposite to the first traveling electric field. A standing wave was created. When an image was focused on the charge transfer device, light was stored in the wells of the standing wave. When the frequency f sub 2 is removed from the device, the standing wave tends to break up and the charges stored move to an electrode connected to an output terminal and to a utilization device where the received charges represent the image on the surface of the charge transfer device along a projection of said straight line.

  1. High Temporal and Spatial Resolution Imaging of Peripheral Vascular Malformations

    PubMed Central

    Mostardi, Petrice M.; Young, Phillip M.; McKusick, Michael A.; Riederer, Stephen J.

    2013-01-01

    Purpose To assess the performance of a recently developed 3D time-resolved CE-MRA technique, Cartesian Acquisition with Projection-Reconstruction-like sampling (CAPR), for accurate characterization and treatment planning of vascular malformations of the periphery. Materials and Methods Twelve patient studies were performed (eight female, four male; average age, 33 years). The protocol consisted of three-dimensional (3D) time-resolved CE-MRA followed by a single late phase T1-weighted acquisition. Vascular malformations were imaged in the forearm, hand, thigh, and foot. Imaging evaluation was performed for accurate characterization of lesion type, identification of feeding and draining vessels, involvement with surrounding tissue, overall quality for diagnosis and treatment planning, and correlation with conventional angiography. Results Time-resolved CE-MRA allowed for characterization of malformation flow and type. Feeding and draining vessels were identified in all cases. Overall quality for diagnosis and treatment planning was 3.58/4.0, and correlation with conventional angiography was scored as 3.89/4.0. Conclusion The CAPR time series has been shown to portray the temporal dynamics and structure of vascular malformations as well as the normal vasculature with high quality. CAPR time-resolved imaging is able to accurately characterize high and low flow lesions, allowing for pretreatment lesion assessment and treatment planning. Delayed imaging is important to capture complete filling of very slow flow vascular malformations. PMID:22674646

  2. Local Optical Spectroscopies for Subnanometer Spatial Resolution Chemical Imaging

    SciTech Connect

    Weiss, Paul

    2014-01-20

    The evanescently coupled photon scanning tunneling microscopes (STMs) have special requirements in terms of stability and optical access. We have made substantial improvements to the stability, resolution, and noise floor of our custom-built visible-photon STM, and will translate these advances to our infrared instrument. Double vibration isolation of the STM base with a damping system achieved increased rigidity, giving high tunneling junction stability for long-duration and high-power illumination. Light frequency modulation with an optical chopper and phase-sensitive detection now enhance the signal-to-noise ratio of the tunneling junction during irradiation.

  3. Spatial Resolution Characterization for QuickBird Image Products 2003-2004 Season

    NASA Technical Reports Server (NTRS)

    Blonski, Slawomir

    2006-01-01

    This presentation focuses on spatial resolution characterization for QuickBird panochromatic images in 2003-2004 and presents data measurements and analysis of SSC edge target deployment and edge response extraction and modeling. The results of the characterization are shown as values of the Modulation Transfer Function (MTF) at the Nyquist spatial frequency and as the Relative Edge Response (RER) components. The results show that RER is much less sensitive to accuracy of the curve fitting than the value of MTF at Nyquist frequency. Therefore, the RER/edge response slope is a more robust estimator of the digital image spatial resolution than the MTF. For the QuickBird panochromatic images, the RER is consistently equal to 0.5 for images processed with the Cubic Convolution resampling and to 0.8 for the MTF resampling.

  4. Full-reference quality estimation for images with different spatial resolutions.

    PubMed

    Demirtas, Ali Murat; Reibman, Amy R; Jafarkhani, Hamid

    2014-05-01

    Multimedia communication is becoming pervasive because of the progress in wireless communications and multimedia coding. Estimating the quality of the visual content accurately is crucial in providing satisfactory service. State of the art visual quality assessment approaches are effective when the input image and reference image have the same resolution. However, finding the quality of an image that has spatial resolution different than that of the reference image is still a challenging problem. To solve this problem, we develop a quality estimator (QE), which computes the quality of the input image without resampling the reference or the input images. In this paper, we begin by identifying the potential weaknesses of previous approaches used to estimate the quality of experience. Next, we design a QE to estimate the quality of a distorted image with a lower resolution compared with the reference image. We also propose a subjective test environment to explore the success of the proposed algorithm in comparison with other QEs. When the input and test images have different resolutions, the subjective tests demonstrate that in most cases the proposed method works better than other approaches. In addition, the proposed algorithm also performs well when the reference image and the test image have the same resolution. PMID:24686279

  5. Optimal Spatial Resolution of Omnidirectional Imaging Systems for Pipe Inspection Applications

    NASA Astrophysics Data System (ADS)

    Dehghan Tezerjani, Abbasali; Mehrandezh, Mehran; Paranjape, Raman

    2015-10-01

    Achieving optimal spatial resolution in imaging systems plays a major role in the design of vision-based industrial inspection tools. Single-view omnidirectional imaging systems provide a cost-effective and computationally-traceable solution for real-time inspection of infrastructure with a favorable size factor. We formulate, for the first time, the spatial cylindrical resolution of omnidirectional Catadioptric and Dioptric imaging systems with the focus on pipe inspection applications. We also provide a design guideline to achieve the highest resolution in these systems. First, we deliver a comprehensive study on optimal resolution in Catadioptric imaging systems which consist of a perspective pinhole camera, a collimated laser as the light source, and a reflective surface (i.e., hyperbolic mirror). Variation of the spatial resolution in terms of the camera's focal length, the mirror curvature, and the relative position between the laser projector and the camera is fully investigated via simulation and experiments. Also, the optimal resolution in Dioptric systems, which consist of a camera with compound refractive lenses (i.e., fish-eye lens) is studied and compared with that in Catadioptric systems. Tests were conducted on a 40-cm-diameter PVC pipe in a controlled laboratory environment.

  6. Two-photon imaging of spatially extended neuronal network dynamics with high temporal resolution

    PubMed Central

    Lillis, Kyle P.; Eng, Alfred; White, John A.; Mertz, Jerome

    2008-01-01

    We describe a simple two-photon fluorescence imaging strategy, called targeted path scanning (TPS), to monitor the dynamics of spatially extended neuronal networks with high spatiotemporal resolution. Our strategy combines the advantages of mirror-based scanning, minimized dead time, ease of implementation, and compatibility with high-resolution low-magnification objectives. To demonstrate the performance of TPS, we monitor the calcium dynamics distributed across an entire juvenile rat hippocampus (>1.5mm), at scan rates of 100Hz, with single cell resolution and single action potential sensitivity. Our strategy for fast, efficient two-photon microscopy over spatially extended regions provides a particularly attractive solution for monitoring neuronal population activity in thick tissue, without sacrificing the signal to noise ratio or high spatial resolution associated with standard two-photon microscopy. Finally, we provide the code to make our technique generally available. PMID:18539336

  7. High spatial resolution gamma imaging detector based on a 5 inch diameter R3292 Hamamatsu PSPMT

    SciTech Connect

    Wojcik, R.; Majewski, S.; Kross, B.; Weisenberger, A.G.; Steinbach, D.

    1998-06-01

    High resolution imaging gamma-ray detectors were developed using Hamamatsu`s 5 inch diameter R3292 position sensitive PMT (PSPMT) and a variety of crystal scintillator arrays. Special readout techniques were used to maximize the active imaging area while reducing the number of readout channels. Spatial resolutions approaching 1 mm were obtained in a broad energy range from 20 to 511 keV. Results are also presented of coupling the scintillator arrays to the PMT via imaging light guides consisting of acrylic optical fibers.

  8. High-Resolution Image Classification Integrating Spectral-Spatial-Location Cues by Conditional Random Fields.

    PubMed

    Zhao, Ji; Zhong, Yanfei; Shu, Hong; Zhang, Liangpei

    2016-09-01

    With the increase in the availability of high-resolution remote sensing imagery, classification is becoming an increasingly useful technique for providing a large area of detailed land-cover information by the use of these high-resolution images. High-resolution images have the characteristics of abundant geometric and detail information, which are beneficial to detailed classification. In order to make full use of these characteristics, a classification algorithm based on conditional random fields (CRFs) is presented in this paper. The proposed algorithm integrates spectral, spatial contextual, and spatial location cues by modeling the probabilistic potentials. The spectral cues modeled by the unary potentials can provide basic information for discriminating the various land-cover classes. The pairwise potentials consider the spatial contextual information by establishing the neighboring interactions between pixels to favor spatial smoothing. The spatial location cues are explicitly encoded in the higher order potentials. The higher order potentials consider the nonlocal range of the spatial location interactions between the target pixel and its nearest training samples. This can provide useful information for the classes that are easily confused with other land-cover types in the spectral appearance. The proposed algorithm integrates spectral, spatial contextual, and spatial location cues within a CRF framework to provide complementary information from varying perspectives, so that it can address the common problem of spectral variability in remote sensing images, which is directly reflected in the accuracy of each class and the average accuracy. The experimental results with three high-resolution images show the validity of the algorithm, compared with the other state-of-the-art classification algorithms. PMID:27295673

  9. High spatial resolution X-ray and gamma ray imaging system using diffraction crystals

    DOEpatents

    Smither, Robert K.

    2011-05-17

    A method and a device for high spatial resolution imaging of a plurality of sources of x-ray and gamma-ray radiation are provided. The device comprises a plurality of arrays, with each array comprising a plurality of elements comprising a first collimator, a diffracting crystal, a second collimator, and a detector.

  10. High Spatial Resolution Isotope Ratio Imaging and 3D Reconstruction of Presolar SiC Grains

    NASA Astrophysics Data System (ADS)

    Lyon, I. C.; Henkel, T.; Clarke, A.

    2015-07-01

    Presolar SiC grains have been analysed with a new NanoSIMS for isotope ratio measurements of C, N and Si. High spatial resolution imaging suggests that nitrogen isotope heterogeneity within the grains may lead to anomalous results in the literature.

  11. Assessing spatial resolution versus sensitivity from laser speckle contrast imaging: application to frequency analysis.

    PubMed

    Bricq, Stéphanie; Mahé, Guillaume; Rousseau, David; Humeau-Heurtier, Anne; Chapeau-Blondeau, François; Varela, Julio Rojas; Abraham, Pierre

    2012-10-01

    For blood perfusion monitoring, laser speckle contrast (LSC) imaging is a recent non-contact technique that has the characteristic of delivering noise-like speckled images. To exploit LSC images for quantitative physiological measurements, we developed an approach that implements controlled spatial averaging to reduce the detrimental impact of the noise and improve measurement sensitivity. By this approach, spatial resolution and measurement sensitivity can be traded-off in a flexible way depending on the quantitative prospect of the study. As an application, detectability of the cardiac activity from LSC images of forearm using power spectrum analysis is studied through the construction of spatial activity maps offering a window on the blood flow perfusion and its regional distribution. Comparisons with results obtained with signals of laser Doppler flowmetry probes are performed. PMID:22644256

  12. On the assessment of spatial resolution of PET systems with iterative image reconstruction

    NASA Astrophysics Data System (ADS)

    Gong, Kuang; Cherry, Simon R.; Qi, Jinyi

    2016-03-01

    Spatial resolution is an important metric for performance characterization in PET systems. Measuring spatial resolution is straightforward with a linear reconstruction algorithm, such as filtered backprojection, and can be performed by reconstructing a point source scan and calculating the full-width-at-half-maximum (FWHM) along the principal directions. With the widespread adoption of iterative reconstruction methods, it is desirable to quantify the spatial resolution using an iterative reconstruction algorithm. However, the task can be difficult because the reconstruction algorithms are nonlinear and the non-negativity constraint can artificially enhance the apparent spatial resolution if a point source image is reconstructed without any background. Thus, it was recommended that a background should be added to the point source data before reconstruction for resolution measurement. However, there has been no detailed study on the effect of the point source contrast on the measured spatial resolution. Here we use point source scans from a preclinical PET scanner to investigate the relationship between measured spatial resolution and the point source contrast. We also evaluate whether the reconstruction of an isolated point source is predictive of the ability of the system to resolve two adjacent point sources. Our results indicate that when the point source contrast is below a certain threshold, the measured FWHM remains stable. Once the contrast is above the threshold, the measured FWHM monotonically decreases with increasing point source contrast. In addition, the measured FWHM also monotonically decreases with iteration number for maximum likelihood estimate. Therefore, when measuring system resolution with an iterative reconstruction algorithm, we recommend using a low-contrast point source and a fixed number of iterations.

  13. 3D high spectral and spatial resolution imaging of ex vivo mouse brain

    SciTech Connect

    Foxley, Sean Karczmar, Gregory S.; Domowicz, Miriam; Schwartz, Nancy

    2015-03-15

    Purpose: Widely used MRI methods show brain morphology both in vivo and ex vivo at very high resolution. Many of these methods (e.g., T{sub 2}{sup *}-weighted imaging, phase-sensitive imaging, or susceptibility-weighted imaging) are sensitive to local magnetic susceptibility gradients produced by subtle variations in tissue composition. However, the spectral resolution of commonly used methods is limited to maintain reasonable run-time combined with very high spatial resolution. Here, the authors report on data acquisition at increased spectral resolution, with 3-dimensional high spectral and spatial resolution MRI, in order to analyze subtle variations in water proton resonance frequency and lineshape that reflect local anatomy. The resulting information compliments previous studies based on T{sub 2}{sup *} and resonance frequency. Methods: The proton free induction decay was sampled at high resolution and Fourier transformed to produce a high-resolution water spectrum for each image voxel in a 3D volume. Data were acquired using a multigradient echo pulse sequence (i.e., echo-planar spectroscopic imaging) with a spatial resolution of 50 × 50 × 70 μm{sup 3} and spectral resolution of 3.5 Hz. Data were analyzed in the spectral domain, and images were produced from the various Fourier components of the water resonance. This allowed precise measurement of local variations in water resonance frequency and lineshape, at the expense of significantly increased run time (16–24 h). Results: High contrast T{sub 2}{sup *}-weighted images were produced from the peak of the water resonance (peak height image), revealing a high degree of anatomical detail, specifically in the hippocampus and cerebellum. In images produced from Fourier components of the water resonance at −7.0 Hz from the peak, the contrast between deep white matter tracts and the surrounding tissue is the reverse of the contrast in water peak height images. This indicates the presence of a shoulder in

  14. Spatial resolution of imaging plate with flash X-rays and its utilization for radiography

    SciTech Connect

    Shaikh, A. M.; Romesh, C.; Kolage, T. S.; Sharma, Archana

    2015-06-24

    A flash X-ray source developed using pulsed electron accelerator with electron energy range of 400keV to 1030keV and a field emission cathode is characterized using X-ray imaging plates. Spatial resolution of the imaging system is measured using edge spread function fitted to data obtained from radiograph of Pb step wedge. A spatial resolution of 150±6 µm is obtained. The X-ray beam size is controlled by the anode-cathode configuration. Optimum source size of ∼13±2 mm diameter covering an area with intensity of ∼27000 PSL/mm{sup 2} is obtained on the imaging plate kept at a distance of ∼200 mm from the tip of the anode. It is used for recording radiographs of objects like satellite cable cutter, aero-engine turbine blade and variety of pyro-devices used in aerospace industry.

  15. Spatial resolution of imaging plate with flash X-rays and its utilization for radiography

    NASA Astrophysics Data System (ADS)

    Shaikh, A. M.; Romesh, C.; Kolage, T. S.; Sharma, Archana

    2015-06-01

    A flash X-ray source developed using pulsed electron accelerator with electron energy range of 400keV to 1030keV and a field emission cathode is characterized using X-ray imaging plates. Spatial resolution of the imaging system is measured using edge spread function fitted to data obtained from radiograph of Pb step wedge. A spatial resolution of 150±6 µm is obtained. The X-ray beam size is controlled by the anode-cathode configuration. Optimum source size of ˜13±2 mm diameter covering an area with intensity of ˜27000 PSL/mm2 is obtained on the imaging plate kept at a distance of ˜200 mm from the tip of the anode. It is used for recording radiographs of objects like satellite cable cutter, aero-engine turbine blade and variety of pyro-devices used in aerospace industry

  16. Spatial resolution recovery utilizing multi-ray tracing and graphic processing unit in PET image reconstruction

    NASA Astrophysics Data System (ADS)

    Liang, Yicheng; Peng, Hao

    2015-02-01

    Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity.

  17. Spatial resolution recovery utilizing multi-ray tracing and graphic processing unit in PET image reconstruction.

    PubMed

    Liang, Yicheng; Peng, Hao

    2015-02-01

    Depth-of-interaction (DOI) poses a major challenge for a PET system to achieve uniform spatial resolution across the field-of-view, particularly for small animal and organ-dedicated PET systems. In this work, we implemented an analytical method to model system matrix for resolution recovery, which was then incorporated in PET image reconstruction on a graphical processing unit platform, due to its parallel processing capacity. The method utilizes the concepts of virtual DOI layers and multi-ray tracing to calculate the coincidence detection response function for a given line-of-response. The accuracy of the proposed method was validated for a small-bore PET insert to be used for simultaneous PET/MR breast imaging. In addition, the performance comparisons were studied among the following three cases: 1) no physical DOI and no resolution modeling; 2) two physical DOI layers and no resolution modeling; and 3) no physical DOI design but with a different number of virtual DOI layers. The image quality was quantitatively evaluated in terms of spatial resolution (full-width-half-maximum and position offset), contrast recovery coefficient and noise. The results indicate that the proposed method has the potential to be used as an alternative to other physical DOI designs and achieve comparable imaging performances, while reducing detector/system design cost and complexity. PMID:25591118

  18. Effects of spatial resolution and spectral purity on transvenous coronary angiography images

    SciTech Connect

    Chapman, D.; Thomlinson, W.; Gumer, N.F.

    1994-11-01

    Measurements have been made on the National Synchrotron Light Source (NSLS) Coronary Angiography X17B2 beamline under ideal and real imaging conditions to investigate the optimal imaging conditions for spatial resolution and spectral purity. The spatial resolution tests were performed using two multielement Si(Li) detectors (600 element, 0.5mm, pixel-pixel spacing; 1200 element, 0.25mm pixel-pixel spacing. Images were taken of phantoms containing iodine contrast agent over a wide range of incident beam absorption conditions. Patient images were also obtained using the same viewing projection with both detectors. Harmonics present in the imaging beam can be reduced by operating the superconducting wiggler source at reduced field strength. At regions of high absorption in the patient, the harmonics present can contribute to the detected signal. Iodine phantom images were obtained at a wiggler field strength of 3 Tesla (E{sub c}=13.3keV) and 4 Tesla (E{sub c}= I 7.8keV) for comparison. As before, patient images were obtained using the same projection at both wiggler fields. Results of the detector resolution and wiggler eld measurements will be presented for the phantoms as well as the patient scans.

  19. High-resolution digital holographic imaging by using a spatial light modulator

    NASA Astrophysics Data System (ADS)

    Li, Bin; Wang, Da-Yong; Wang, Yun-Xin; Rong, Lu

    2014-09-01

    Digital holography is the product of the optical holography, computer technology and photoelectric detection technology, and has the advantage of high-speed, real-time, full field of view, non-contact and quantitative phase contrast imaging. However, the numerical aperture of the hologram is limited due to the smaller sensitive area of the photoelectric sensor and the larger pixel size, and it is uneasy to meet the practical requirement on the imaging resolution. An approach is presented to achieve the high-resolution digital holographic imaging based on a spatial light modulator(SLM). An amplitude spatial light modulator is placed between the object and the CCD in the lensless Fourier transform digital holographic imaging system. The distribution of a diffraction grating is loaded into the SLM. In this way, more light including the high-frequency content, diffracted from the object, can be collected by the CCD. The standard resolution target is used as the object. The reconstructed image is obtained by the Fresnel diffraction propagation algorithm, which exhibits three diffraction orders. The results show that the resolution is improved from 62.5 μm to 31.3 μm.

  20. Super-resolution reconstruction to increase the spatial resolution of diffusion weighted images from orthogonal anisotropic acquisitions.

    PubMed

    Scherrer, Benoit; Gholipour, Ali; Warfield, Simon K

    2012-10-01

    Diffusion-weighted imaging (DWI) enables non-invasive investigation and characterization of the white matter but suffers from a relatively poor spatial resolution. Increasing the spatial resolution in DWI is challenging with a single-shot EPI acquisition due to the decreased signal-to-noise ratio and T2(∗) relaxation effect amplified with increased echo time. In this work we propose a super-resolution reconstruction (SRR) technique based on the acquisition of multiple anisotropic orthogonal DWI scans. DWI scans acquired in different planes are not typically closely aligned due to the geometric distortion introduced by magnetic susceptibility differences in each phase-encoding direction. We compensate each scan for geometric distortion by acquisition of a dual echo gradient echo field map, providing an estimate of the field inhomogeneity. We address the problem of patient motion by aligning the volumes in both space and q-space. The SRR is formulated as a maximum a posteriori problem. It relies on a volume acquisition model which describes how the acquired scans are observations of an unknown high-resolution image which we aim to recover. Our model enables the introduction of image priors that exploit spatial homogeneity and enables regularized solutions. We detail our SRR optimization procedure and report experiments including numerical simulations, synthetic SRR and real world SRR. In particular, we demonstrate that combining distortion compensation and SRR provides better results than acquisition of a single isotropic scan for the same acquisition duration time. Importantly, SRR enables DWI with resolution beyond the scanner hardware limitations. This work provides the first evidence that SRR, which employs conventional single shot EPI techniques, enables resolution enhancement in DWI, and may dramatically impact the role of DWI in both neuroscience and clinical applications. PMID:22770597

  1. SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) for low dose x-ray imaging: Spatial resolution

    PubMed Central

    Li, Dan; Zhao, Wei

    2008-01-01

    An indirect flat panel imager (FPI) with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low-dose and high resolution x-ray imaging. It is made by optically coupling a structured x-ray scintillator, e.g., thallium (Tl) doped cesium iodide (CsI), to an amorphous selenium (a-Se) avalanche photoconductor called high-gain avalanche rushing amorphous photoconductor (HARP). The charge image created by the scintillator∕HARP (SHARP) combination is read out by the electron beams emitted from the FEA. The proposed detector is called scintillator avalanche photoconductor with high resolution emitter readout (SAPHIRE). The programmable avalanche gain of HARP can improve the low dose performance of indirect FPI while the FEA can be made with pixel sizes down to 50 μm. Because of the avalanche gain, a high resolution type of CsI (Tl), which has not been widely used in indirect FPI due to its lower light output, can be used to improve the high spatial frequency performance. The purpose of the present article is to investigate the factors affecting the spatial resolution of SAPHIRE. Since the resolution performance of the SHARP combination has been well studied, the focus of the present work is on the inherent resolution of the FEA readout method. The lateral spread of the electron beam emitted from a 50 μm×50 μm pixel FEA was investigated with two different electron-optical designs: mesh-electrode-only and electrostatic focusing. Our results showed that electrostatic focusing can limit the lateral spread of electron beams to within the pixel size of down to 50 μm. Since electrostatic focusing is essentially independent of signal intensity, it will provide excellent spatial uniformity. PMID:18697540

  2. SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) for low dose x-ray imaging: Spatial resolution

    SciTech Connect

    Li Dan; Zhao Wei

    2008-07-15

    An indirect flat panel imager (FPI) with programmable avalanche gain and field emitter array (FEA) readout is being investigated for low-dose and high resolution x-ray imaging. It is made by optically coupling a structured x-ray scintillator, e.g., thallium (Tl) doped cesium iodide (CsI), to an amorphous selenium (a-Se) avalanche photoconductor called high-gain avalanche rushing amorphous photoconductor (HARP). The charge image created by the scintillator/HARP (SHARP) combination is read out by the electron beams emitted from the FEA. The proposed detector is called scintillator avalanche photoconductor with high resolution emitter readout (SAPHIRE). The programmable avalanche gain of HARP can improve the low dose performance of indirect FPI while the FEA can be made with pixel sizes down to 50 {mu}m. Because of the avalanche gain, a high resolution type of CsI (Tl), which has not been widely used in indirect FPI due to its lower light output, can be used to improve the high spatial frequency performance. The purpose of the present article is to investigate the factors affecting the spatial resolution of SAPHIRE. Since the resolution performance of the SHARP combination has been well studied, the focus of the present work is on the inherent resolution of the FEA readout method. The lateral spread of the electron beam emitted from a 50 {mu}mx50 {mu}m pixel FEA was investigated with two different electron-optical designs: mesh-electrode-only and electrostatic focusing. Our results showed that electrostatic focusing can limit the lateral spread of electron beams to within the pixel size of down to 50 {mu}m. Since electrostatic focusing is essentially independent of signal intensity, it will provide excellent spatial uniformity.

  3. Effect of optical tissue clearing on spatial resolution and sensitivity of bioluminescence imaging

    NASA Astrophysics Data System (ADS)

    Jansen, Eric D.; Pickett, Patrick M.; Mackanos, Mark A.; Virostko, Jack

    2006-07-01

    In vivo bioluminescence imaging (BLI) is a powerful method of in vivo molecular imaging based on the use of optically active luciferase reporter genes. Although this method provides superior sensitivity relative to other in vivo imaging methods, spatial resolution is poor due to light scattering. The objective of this study was to use hyperosmotic agents to reduce the scattering coefficient and hence improve spatial resolution of the BLI method. A diffusing fiber tip was used to simulate an isotropic point source of bioluminescence emission (550 to 650 nm). Mouse skin was treated in vitro and in vivo with glycerol (50%, 30 min) and measurements of optical properties, and imaging photon counts were made before, during, and after application of glycerol to the skin sample. Glycerol application to mouse skin had little effect on the absorption coefficient but reduced the reduced scattering coefficient by more than one order of magnitude. This effect was reversible. Consequently, the spot size (i.e., spatial resolution) of the bioluminescence point source imaged through the skin decreased by a factor of 2 (550-nm light) to 3 (650-nm light) after 30 min. Simultaneously, an almost twofold decrease in the amount of light detected by the BLI system was observed, despite the fact that total transmission increased 1.7 times. We have shown here that multiply scattered light is responsible for both observations. We have shown that applying a hyperosmotic clearing agent to the skin of small rodents has the potential to improve spatial resolution of BLI owing to a reduction in the reduced scattering coefficient in the skin by one order of magnitude. However, reducing the scattering coefficient reduces the amount of light reaching the camera due to a reduction in the amount of multiply scattered light that reaches the camera aperture and thus reducing the sensitivity of the method.

  4. Fundamental x-ray interaction limits in diagnostic imaging detectors: spatial resolution.

    PubMed

    Hajdok, G; Battista, J J; Cunningham, I A

    2008-07-01

    The practice of diagnostic x-ray imaging has been transformed with the emergence of digital detector technology. Although digital systems offer many practical advantages over conventional film-based systems, their spatial resolution performance can be a limitation. The authors present a Monte Carlo study to determine fundamental resolution limits caused by x-ray interactions in four converter materials: Amorphous silicon (a-Si), amorphous selenium, cesium iodide, and lead iodide. The "x-ray interaction" modulation transfer function (MTF) was determined for each material and compared in terms of the 50% MTF spatial frequency and Wagner's effective aperture for incident photon energies between 10 and 150 keV and various converter thicknesses. Several conclusions can be drawn from their Monte Carlo study. (i) In low-Z (a-Si) converters, reabsorption of Compton scatter x rays limits spatial resolution with a sharp MTF drop at very low spatial frequencies (< 0.3 cycles/mm), especially above 60 keV; while in high-Z materials, reabsorption of characteristic x rays plays a dominant role, resulting in a mid-frequency (1-5 cycles/mm) MTF drop. (ii) Coherent scatter plays a minor role in the x-ray interaction MTF. (iii) The spread of energy due to secondary electron (e.g., photoelectrons) transport is significant only at very high spatial frequencies. (iv) Unlike the spread of optical light in phosphors, the spread of absorbed energy from x-ray interactions does not significantly degrade spatial resolution as converter thickness is increased. (v) The effective aperture results reported here represent fundamental spatial resolution limits of the materials tested and serve as target benchmarks for the design and development of future digital x-ray detectors. PMID:18697543

  5. Fundamental x-ray interaction limits in diagnostic imaging detectors: Spatial resolution

    SciTech Connect

    Hajdok, G.; Battista, J. J.; Cunningham, I. A.

    2008-07-15

    The practice of diagnostic x-ray imaging has been transformed with the emergence of digital detector technology. Although digital systems offer many practical advantages over conventional film-based systems, their spatial resolution performance can be a limitation. The authors present a Monte Carlo study to determine fundamental resolution limits caused by x-ray interactions in four converter materials: Amorphous silicon (a-Si), amorphous selenium, cesium iodide, and lead iodide. The ''x-ray interaction'' modulation transfer function (MTF) was determined for each material and compared in terms of the 50% MTF spatial frequency and Wagner's effective aperture for incident photon energies between 10 and 150 keV and various converter thicknesses. Several conclusions can be drawn from their Monte Carlo study. (i) In low-Z (a-Si) converters, reabsorption of Compton scatter x rays limits spatial resolution with a sharp MTF drop at very low spatial frequencies (<0.3 cycles/mm), especially above 60 keV; while in high-Z materials, reabsorption of characteristic x rays plays a dominant role, resulting in a mid-frequency (1-5 cycles/mm) MTF drop. (ii) Coherent scatter plays a minor role in the x-ray interaction MTF. (iii) The spread of energy due to secondary electron (e.g., photoelectrons) transport is significant only at very high spatial frequencies. (iv) Unlike the spread of optical light in phosphors, the spread of absorbed energy from x-ray interactions does not significantly degrade spatial resolution as converter thickness is increased. (v) The effective aperture results reported here represent fundamental spatial resolution limits of the materials tested and serve as target benchmarks for the design and development of future digital x-ray detectors.

  6. Increasing spatial resolution and comparison of MR imaging sequences for the inner ear

    NASA Astrophysics Data System (ADS)

    Snyder, Carl J.; Bolinger, Lizann; Rubinstein, Jay T.; Wang, Ge

    2002-04-01

    The size and location of the cochlea and cochlear nerve are needed to assess the feasibility of cochlea implantation, provide information for surgical planning, and aid in construction of cochlear models. Models of implant stimulation incorporating anatomical and physiological information are likely to provide a better understanding of the biophysics of information transferred with cochlear implants and aid in electrode design and arrangement on cochlear implants. Until recently MR did not provide the necessary image resolution and suffered from long acquisition times. The purpose of this study was to optimize both Fast Spin Echo (FSE) and Steady State Free Precession (FIESTA) imaging scan parameters for the inner ear and comparatively examine both for improved image quality and increased spatial resolution. Image quality was determined by two primary measurements, signal to noise ratio (SNR), and image sharpness. Optimized parameters for FSE were 120ms, 3000ms, 64, and 32.25kHz for the TE, TR, echo train length, and bandwidth, respectively. FIESTA parameters were optimized to 2.7, 5.5ms, 70 degree(s), and 62.5kHz, for TE, TR, flip angle, and bandwidth, respectively. While both had the same in-plane spatial resolution, 0.625mm, FIESTA data shows higher SNR per acquisition time and better edge sharpness.

  7. Spatial resolution, signal-to-noise and information capacity of linear imaging systems.

    PubMed

    Gureyev, Timur; Nesterets, Yakov; de Hoog, Frank

    2016-07-25

    A simple model for image formation in linear shift-invariant systems is considered, in which both the detected signal and the noise variance are varying slowly compared to the point-spread function of the system. It is shown that within the constraints of this model, the square of the signal-to-noise ratio is always proportional to the "volume" of the spatial resolution unit. In the case of Poisson statistics, the ratio of these two quantities divided by the incident density of the imaging particles (e.g. photons) represents a dimensionless invariant of the imaging system, which was previously termed the intrinsic imaging quality. The relationship of this invariant to the notion of information capacity of communication and imaging systems, which was previously considered by Shannon, Gabor and others, is investigated. The results are then applied to a simple generic model of quantitative imaging of weakly scattering objects, leading to an estimate of the upper limit for the amount of information about the sample that can be obtained in such experiments. It is shown that this limit depends only on the total number of imaging particles incident on the sample, the average scattering coefficient, the size of the sample and the number of spatial resolution units. PMID:27464167

  8. Synthesis of imagery with high spatial and spectral resolution from multiple image sources

    NASA Astrophysics Data System (ADS)

    Filiberti, Daniel P.; Marsh, Stuart E.; Schowengerdt, Robert A.

    1994-08-01

    We demonstrate how a realistic scene with high spatial and spectral resolution can be synthesized from color aerial photography and AVIRIS hyperspectral imagery. A review of techniques for image fusion is first presented. Image processing techniques were developed to extract a digital elevation model from stereo aerial photography in order to correct temporal shading differences between two image sets and to fuse aerial photography with AVIRIS imagery. A unique contribution is the explicit inclusion of corrections for topography and differing solar angles in fusion process. Color infrared photography and an AVIRIS image from a site near Cuprite, Nevada, were used as a test of an improved high-frequency modulation technique for the creation of hybrid images. Comparison of spectra extracted from the synthesized image with library spectra demonstrated that our methodology successfully preserved the spectral signatures of the ground surface.

  9. A robust mosaicking procedure for high spatial resolution remote sensing images

    NASA Astrophysics Data System (ADS)

    Li, Xinghua; Hui, Nian; Shen, Huanfeng; Fu, Yunjie; Zhang, Liangpei

    2015-11-01

    With the rapid development of sensor manufacturing technology, high spatial resolution (HR) images are becoming more easily acquired and more widely used. However, it is common that a region of interest (ROI) cannot be completely acquired from a single image. Image mosaicking can resolve the problem by creating a new large-area image from multiple images with overlapping areas. A typical mosaicking procedure for HR remote sensing images includes three successive steps: tonal adjustment, seamline detection, and image blending. In this paper, we propose a robust mosaicking procedure featuring novel ideas in all three steps, which is aimed at processing HR remote sensing images of urban areas. Firstly, the tonal adjustment is realized by a local moment matching (LMM) algorithm, which solves the nonlinear photometric correlation problem between adjacent images. Secondly, an automatic piecewise dynamic program (APDP) algorithm for seamline detection is proposed to detect the optimal seamline on the overlapped area. Last but not least, we propose a cosine distance weighted blending (CDWB) method to ensure that the seamline is as invisible as possible. Compared to the state-of-the-art methods, the proposed method was proved to be effective in experiments with high resolution aerial and satellite images.

  10. Classification of high resolution satellite images using spatial constraints-based fuzzy clustering

    NASA Astrophysics Data System (ADS)

    Singh, Pankaj Pratap; Garg, Rahul Dev

    2014-01-01

    A spatial constraints-based fuzzy clustering technique is introduced in the paper and the target application is classification of high resolution multispectral satellite images. This fuzzy-C-means (FCM) technique enhances the classification results with the help of a weighted membership function (Wmf). Initially, spatial fuzzy clustering (FC) is used to segment the targeted vegetation areas with the surrounding low vegetation areas, which include the information of spatial constraints (SCs). The performance of the FCM image segmentation is subject to appropriate initialization of Wmf and SC. It is able to evolve directly from the initial segmentation by spatial fuzzy clustering. The controlling parameters in fuzziness of the FCM approach, Wmf and SC, help to estimate the segmented road results, then the Stentiford thinning algorithm is used to estimate the road network from the classified results. Such improvements facilitate FCM method manipulation and lead to segmentation that is more robust. The results confirm its effectiveness for satellite image classification, which extracts useful information in suburban and urban areas. The proposed approach, spatial constraint-based fuzzy clustering with a weighted membership function (SCFCWmf), has been used to extract the information of healthy trees with vegetation and shadows showing elevated features in satellite images. The performance values of quality assessment parameters show a good degree of accuracy for segmented roads using the proposed hybrid SCFCWmf-MO (morphological operations) approach which also occluded nonroad parts.

  11. A versatile fluorescence lifetime imaging system for scanning large areas with high time and spatial resolution

    NASA Astrophysics Data System (ADS)

    Bernardo, César; Belsley, Michael; de Matos Gomes, Etelvina; Gonçalves, Hugo; Isakov, Dmitry; Liebold, Falk; Pereira, Eduardo; Pires, Vladimiro; Samantilleke, Anura; Vasilevskiy, Mikhail; Schellenberg, Peter

    2014-08-01

    We present a flexible fluorescence lifetime imaging device which can be employed to scan large sample areas with a spatial resolution adjustable from many micrometers down to sub-micrometers and a temporal resolution of 20 picoseconds. Several different applications of the system will be presented including protein microarrays analysis, the scanning of historical samples, evaluation of solar cell surfaces and nanocrystalline organic crystals embedded in electrospun polymeric nanofibers. Energy transfer processes within semiconductor quantum dot superstructures as well as between dye probes and graphene layers were also investigated.

  12. Effects of finite spatial resolution on quantitative CBF images from dynamic PET

    SciTech Connect

    Phelps, M.E.; Huang, S.C.; Mahoney, D.K.

    1985-05-01

    The finite spatial resolution of PET causes the time-activity responses on pixels around the boundaries between gray and white matter regions to contain kinetic components from tissues of different CBF's. CBF values estimated from kinetics of such mixtures are underestimated because of the nonlinear relationship between the time-activity response and the estimated CBF. Computer simulation is used to investigate these effects on phantoms of circular structures and realistic brain slice in terms of object size and quantitative CBF values. The CBF image calculated is compared to the case of having resolution loss alone. Results show that the size of a high flow region in the CBF image is decreased while that of a low flow region is increased. For brain phantoms, the qualitative appearance of CBF images is not seriously affected, but the estimated CBF's are underestimated by 11 to 16 percent in local gray matter regions (of size 1 cm/sup 2/) with about 14 percent reduction in global CBF over the whole slice. It is concluded that the combined effect of finite spatial resolution and the nonlinearity in estimating CBF from dynamic PET is quite significant and must be considered in processing and interpreting quantitative CBF images.

  13. A high spatial resolution Stokes polarimeter for motional Stark effect imaging

    SciTech Connect

    Thorman, Alex; Michael, Clive; Howard, John

    2013-06-15

    We describe an enhanced temporally switched interfero-polarimeter that has been successfully deployed for high spatial resolution motional Stark effect imaging on the KSTAR superconducting tokamak. The system utilizes dual switching ferroelectric liquid crystal waveplates to image the full Stokes vector of elliptically polarized and Doppler-shifted Stark-Zeeman Balmer-alpha emission from high energy neutral beams injected into the magnetized plasma. We describe the optical system and compare its performance against a Mueller matrix model that takes account of non-ideal performance of the switching ferro-electric liquid crystal waveplates and other polarizing components.

  14. Study on mosaic method for new mode satellite images with high spatial resolution covering urban areas

    NASA Astrophysics Data System (ADS)

    Ran, Qiong; Wang, Zhiyong; Wen, Qiang; Li, Wei; Gao, Lianru

    2014-11-01

    New imaging mode has been brought up for collecting multiple scenes in one pass, as is implemented on World View-II. This greatly helps for acquiring high spatial resolution images that cover urban areas, and is to be adopted in the coming Chinese satellites. This paper is to discuss the mosaic characteristic and propose a mosaic line generation method by integrating correlation and the road information. The mosaic line is formed by linking the unique mosaic point on each line restricted within the road. We position the starting point by connectivity analysis of the road lines, and then locate the adjacent point along the road with connectivity analysis. A weighed vector, combining correlation and distance to centre of the road, is used to pick the best point. The points are located on the road unless it is unavoidable, for example, the road ends or the line touches edge of the image. This method provides instant mosaic line generation for urban areas with road information available in most cases. By resorting to the road, the mosaic line is more applicable since many problems for mosaic of high spatial resolution images are solved, for example, tilting of the buildings, the shadows, motions of the vehicles etc. Experiments have been done with WV-II images and gained favorable results.

  15. HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEWTRON DETECTORS

    SciTech Connect

    FISHER,RK

    2002-10-01

    OAK B202 HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEWTRON DETECTORS. Bubble detectors, which can detect neutrons with a spatial resolution of 5 to 30 {micro}, are a promising approach to high-resolution imaging of NIF target plasmas. Gel bubble detectors were used in successful proof-of-principle imaging experiments on OMEGA. Until recently, bubble detectors appeared to be the only approach capable of achieving neutron images of NIF targets with the desired 5 {micro} spatial resolution in the target plane. In 2001, NIF reduced the required standoff distance from the target, so that diagnostic components can now be placed as close as 10 cm to the target plasma. This will allow neutron imaging with higher magnification and may make it possible to obtain 5 {micro}m resolution images on NIF using deuterated scintillators. Having accomplished all that they can hope to on OMEGA using gel detectors, they suggested that the 2002 NLUF shots be used to allow experimental tests of the spatial resolution of the CEA-built deuterated scintillators. The preliminary CEA data from the June 2002 run appears to show the spatial resolution using the deuterated scintillator detector array is improved over that obtained in earlier experiments using the proton-based scintillators. Gel detectors, which consist of {approx} 10 {micro}m diameter drops of bubble detector liquid suspended in an inactive support gel that occupies {approx} 99% of the detector volume, were chosen for the initial tests on OMEGA since they are easy to use. The bubbles could be photographed several hours after the neutron exposure. Imaging NIF target plasmas at neutron yields of 10{sup 15} will require a higher detection efficiency detector. Using a liquid bubble chamber detector should result in {approx} 1000 times higher neutron detection efficiency which is comparable to that possible using scintillation detectors. A pressure-cycled liquid bubble detector will require a light

  16. Evaluation of spatial resolution in image acquisition by optical flatbed scanners for radiochromic film dosimetry

    NASA Astrophysics Data System (ADS)

    Asero, G.; Greco, C.; Gueli, A. M.; Raffaele, L.; Spampinato, S.

    2016-03-01

    Introduction: Radiochromic films are two-dimensional dosimeters that do not require developing and give values of absorbed dose with accuracy and precision. Since this dosimeter colours directly after irradiation, it can be digitized with commercial optical flatbed scanners to obtain a calibration curve that links blackening of the film with dose. Although the film has an intrinsic high spatial resolution, the scanner determines the actual resolution of this dosimeter, in particular the "dot per inch" (dpi) parameter. The present study investigates the effective spatial resolution of a scanner used for Gafchromic® XR-QA2 film (designed for radiology Quality Assurance) analysis. Material and methods: The quantitative evaluation of the resolution was performed with the Modulation Transfer Function (MTF) method, comparing the nominal resolution with the experimental one. The analysis was performed with two procedures. First, the 1951 USAF resolution test chart, a tool that tests the performance of optical devices, was used. Secondly, a combined system of mammography X-ray tube, XR-QA2 film and a bar pattern object was used. In both cases the MTF method has been applied and the results were compared. Results: The USAF and the film images have been acquired with increasing dpi and a standard protocol for radiochromic analysis, to evaluate horizontal and vertical and resolution. The effective resolution corresponds to the value of the MTF at 50%. In both cases and for both procedures, it was verified that, starting from a dpi value, the effective resolution saturates. Conclusion: The study found that, for dosimetric applications, the dpi of the scanner have to be adjusted to a reasonable value because, if too high, it requires high scanning and computational time without providing additional information.

  17. Measurement Sets and Sites Commonly Used for High Spatial Resolution Image Product Characterization

    NASA Technical Reports Server (NTRS)

    Pagnutti, Mary

    2006-01-01

    Scientists within NASA's Applied Sciences Directorate have developed a well-characterized remote sensing Verification & Validation (V&V) site at the John C. Stennis Space Center (SSC). This site has enabled the in-flight characterization of satellite high spatial resolution remote sensing system products form Space Imaging IKONOS, Digital Globe QuickBird, and ORBIMAGE OrbView, as well as advanced multispectral airborne digital camera products. SSC utilizes engineered geodetic targets, edge targets, radiometric tarps, atmospheric monitoring equipment and their Instrument Validation Laboratory to characterize high spatial resolution remote sensing data products. This presentation describes the SSC characterization capabilities and techniques in the visible through near infrared spectrum and examples of calibration results.

  18. Impulse Response Estimation for Spatial Resolution Enhancement in Ultrasonic NDE Imaging

    SciTech Connect

    Clark, G A

    2004-06-25

    This report describes a signal processing algorithm and MATLAB software for improving spatial resolution in ultrasonic nondestructive evaluation (NDE) imaging of materials. Given a measured reflection signal and an associated reference signal, the algorithm produces an optimal least-squares estimate of the impulse response of the material under test. This estimated impulse response, when used in place of the raw reflection signal, enhances the spatial resolution of the ultrasonic measurements by removing distortion caused by the limited-bandwidth transducers and the materials under test. The theory behind the processing algorithms is briefly presented, while the reader is referred to the bibliography for details. The main focus of the report is to describe how to use the MATLAB software. Two processing examples using actual ultrasonic measurements are provided for tutorial purposes.

  19. Evaluation of ERTS-1 image sensor spatial resolution in photographic form

    NASA Technical Reports Server (NTRS)

    Slater, P. N. (Principal Investigator); Schowengerdt, R. A.

    1973-01-01

    The author has identified the following significant results. A coherent optical system was used to display the spatial frequency content of the amplitude image of one area of the ground as obtained in the four wavelength bands of the multispectral scanner. This enabled a rapid comparison to be made between the four bands, from which it was clear that bands 5 and 7 were preferred to the others in terms of image definition, and thus mapping and acreage estimation, for the particular agricultural area imaged. With suitable scaling it was also possible to compare the modulation, as a function of spatial frequency, of MSS bands 4 and 5 with the green (BB) and red (DD) bands of the same area from the Apollo 9, SO65 experiment. A significant result is that the modulation in the MSS amplitude imagery is 65%-90% of that in the Apollo 9 amplitude imagery. In addition, the ratio of spatial frequencies for the ERTS-1 and Apollo imagery, at which the same modulation occurs, lies between 0.55 and 0.75 for the red band. This ratio is closely related to the ratio of resolutions for the two sensors. These values corroborate statements that the resolution of the MSS imagery is better than anticipated by pre-flight predictions.

  20. The measurement of the presampled MTF of a high spatial resolution neutron imaging system

    NASA Astrophysics Data System (ADS)

    Cao, Raymond Lei.; Biegalski, Steven R.

    2007-11-01

    A high spatial resolution neutron imaging device was developed at the Mark II TRIGA reactor at The University of Texas at Austin. As the modulation transfer function (MTF) is recognized as a well-established parameter for evaluation of imaging system resolution, the aliasing associated with digital sampling adds complexity to its measurement. Aliasing is especially problematic when using a high spatial resolution micro-channel plate (MCP) neutron detector that has a pixel grid size similar to that of a CCD array. To compensate for the aliasing an angulated edge method was used to evaluate the neutron imaging facility, overcoming aliasing by obtaining an oversampled edge spread function (ESF). Baseline correction was applied to the ESF to remove the noticeable trends and the LSF was multiplied by Hann window to obtain a smoothed version of presampled MTF. The computing procedure is confirmed by visual inspection of a testing phantom; in addition, it is confirmed by comparison to the MTF measurement of a scintillation screen with a known MTF curve.

  1. Ultrahigh-spatial-resolution chemical and magnetic imaging by laser-based photoemission electron microscopy

    SciTech Connect

    Taniuchi, Toshiyuki Kotani, Yoshinori; Shin, Shik

    2015-02-15

    We report the first experiments carried out on a new chemical and magnetic imaging system, which combines the high spatial resolution of a photoemission electron microscope (PEEM) with a continuous-wave deep-ultraviolet laser. Threshold photoemission is sensitive to the chemical and magnetic structures of the surface of materials. The spatial resolution of PEEM is limited by space charging when using pulsed photon sources as well as aberrations in the electron optics. We show that the use of a continuous-wave laser enabled us to overcome such a limit by suppressing the space-charge effect, allowing us to obtain a resolution of approximately 2.6 nm. With this system, we demonstrated the imaging of surface reconstruction domains on Si(001) by linear dichroism with normal incidence of the laser beam. We also succeeded in magnetic imaging of thin films with the use of magnetic circular dichroism near the Fermi level. The unique features of the ultraviolet laser will give us fast switching of the incident angles and polarizations of the photon source, which will be useful for the characterization of antiferromagnetic materials as well as ferromagnetic materials.

  2. Effect of Spatial Resolution for Characterizing Soil Properties from Imaging Spectrometer Data

    NASA Astrophysics Data System (ADS)

    Dutta, D.; Kumar, P.; Greenberg, J. A.

    2015-12-01

    The feasibility of quantifying soil constituents over large areas using airborne hyperspectral data [0.35 - 2.5 μm] in an ensemble bootstrapping lasso algorithmic framework has been demonstrated previously [1]. However the effects of coarsening the spatial resolution of hyperspectral data on the quantification of soil constituents are unknown. We use Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data collected at 7.6m resolution over Birds Point New Madrid (BPNM) floodway for up-scaling and generating multiple coarser resolution datasets including the 60m Hyperspectral Infrared Imager (HyspIRI) like data. HyspIRI is a proposed visible shortwave/thermal infrared mission, which will provide global data over a spectral range of 0.35 - 2.5μm at a spatial resolution of 60m. Our results show that the lasso method, which is based on point scale observational data, is scalable. We found consistent good model performance (R2) values (0.79 < R2 < 0.82) and correct classifications as per USDA soil texture classes at multiple spatial resolutions. The results further demonstrate that the attributes of the pdf for different soil constituents across the landscape and the within-pixel variance are well preserved across scales. Our analysis provides a methodological framework with a sufficient set of metrics for assessing the performance of scaling up analysis from point scale observational data and may be relevant for other similar remote sensing studies. [1] Dutta, D.; Goodwell, A.E.; Kumar, P.; Garvey, J.E.; Darmody, R.G.; Berretta, D.P.; Greenberg, J.A., "On the Feasibility of Characterizing Soil Properties From AVIRIS Data," Geoscience and Remote Sensing, IEEE Transactions on, vol.53, no.9, pp.5133,5147, Sept. 2015. doi: 10.1109/TGRS.2015.2417547.

  3. Local rank-based spatial information for improvement of remote sensing hyperspectral imaging resolution.

    PubMed

    Zhang, Xin; Juan, Anna de; Tauler, Romà

    2016-01-01

    This paper shows the effect of using local rank and selectivity constraints based on spatial information of spectroscopic images to increase the performance of Multivariate Curve Resolution (MCR) methods and to decrease the ambiguity of final results. Fixed Size Image Window-Evolving Factor Analysis (FSIW-EFA) is applied to discover which pixels are more suitable for the application of local rank constraints. An automated method to help in setting appropriate threshold values for the application of FSIW-EFA, based on global and local use of Singular Value Decomposition (SVD) is proposed. Additional use of correlation coefficients between selected reference spectra and pixel spectra of the image is shown to provide an alternative way for the application of the selectivity constraint in spectroscopic images for the first time. This alternative method resulted to be satisfactory when pure pixels exist. PMID:26695226

  4. Monitoring of Antarctic moss ecosystems using a high spatial resolution imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Malenovsky, Zbynek; Lucieer, Arko; Robinson, Sharon; Harwin, Stephen; Turner, Darren; Veness, Tony

    2013-04-01

    The most abundant photosynthetically active plants growing along the rocky Antarctic shore are mosses of three species: Schistidium antarctici, Ceratodon purpureus, and Bryum pseudotriquetrum. Even though mosses are well adapted to the extreme climate conditions, their existence in Antarctica depends strongly on availability of liquid water from snowmelt during the short summer season. Recent changes in temperature, wind speed and stratospheric ozone are stimulating faster evaporation, which in turn influences moss growing rate, health state and abundance. This makes them an ideal bio-indicator of the Antarctic climate change. Very short growing season, lasting only about three months, requires a time efficient, easily deployable and spatially resolved method for monitoring the Antarctic moss beds. Ground and/or low-altitude airborne imaging spectroscopy (called also hyperspectral remote sensing) offers a fast and spatially explicit approach to investigate an actual spatial extent and physiological state of moss turfs. A dataset of ground-based spectral images was acquired with a mini-Hyperspec imaging spectrometer (Headwall Inc., the USA) during the Antarctic summer 2012 in the surroundings of the Australian Antarctic station Casey (Windmill Islands). The collection of high spatial resolution spectral images, with pixels about 2 cm in size containing from 162 up to 324 narrow spectral bands of wavelengths between 399 and 998 nm, was accompanied with point moss reflectance measurements recorded with the ASD HandHeld-2 spectroradiometer (Analytical Spectral Devices Inc., the USA). The first spectral analysis indicates significant differences in red-edge and near-infrared reflectance of differently watered moss patches. Contrary to high plants, where the Normalized Difference Vegetation Index (NDVI) represents an estimate of green biomass, NDVI of mosses indicates mainly the actual water content. Similarly to high plants, reflectance of visible wavelengths is

  5. Effects of spatial resolution

    NASA Technical Reports Server (NTRS)

    Abrams, M.

    1982-01-01

    Studies of the effects of spatial resolution on extraction of geologic information are woefully lacking but spatial resolution effects can be examined as they influence two general categories: detection of spatial features per se; and the effects of IFOV on the definition of spectral signatures and on general mapping abilities.

  6. Matrix Recrystallization for MALDI-MS Imaging of Maize Lipids at High-Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Dueñas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

    2016-06-01

    Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

  7. Matrix Recrystallization for MALDI-MS Imaging of Maize Lipids at High-Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Dueñas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

    2016-09-01

    Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

  8. Design of high-resolution variable size spatial filter for Gemini Planet Imager using flexure elements

    NASA Astrophysics Data System (ADS)

    Reshetov, Vlad; Fitzsimmons, Joeleff

    2008-07-01

    This paper presents a design of a variable size spatial filter used in the wavefront sensor subsystem of the Gemini Planet Imager instrument. It describes an adjustable mechanism consisting of two slides forming a square aperture which can be varied in size between 1.8 and 6.7 mm. These slides are located on athermalized flexure mounts that move opposite to one another driven by a single precision linear actuator. The device retains long term dimensional stability, resolution, and repeatability on a micron level for all gravity vector orientations and for temperatures between -5°C and + 25°C.

  9. Matrix Recrystallization for MALDI-MS Imaging of Maize Lipids at High-Spatial Resolution.

    PubMed

    Dueñas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

    2016-09-01

    Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution. Graphical Abstract ᅟ. PMID:27349253

  10. Matrix recrystallization for MALDI-MS imaging of maize lipids at high-spatial resolution

    DOE PAGESBeta

    Duenas, Maria Emilia; Carlucci, Laura; Lee, Young Jin

    2016-06-27

    Matrix recrystallization is optimized and applied to improve lipid ion signals in maize embryos and leaves. A systematic study was performed varying solvent and incubation time. During this study, unexpected side reactions were found when methanol was used as a recrystallization solvent, resulting in the formation of a methyl ester of phosphatidic acid. Furthermore, using an optimum recrystallization condition with isopropanol, there is no apparent delocalization demonstrated with a transmission electron microscopy (TEM) pattern and maize leaf images obtained at 10 μm spatial resolution.

  11. Radiometric Calibration Assessment of Commercial High Spatial Resolution Multispectral Image Products

    NASA Technical Reports Server (NTRS)

    Holekamp, Kara; Aaron, David; Thome, Kurtis

    2006-01-01

    Radiometric calibration of commercial imaging satellite products is required to ensure that science and application communities can better understand their properties. Inaccurate radiometric calibrations can lead to erroneous decisions and invalid conclusions and can limit intercomparisons with other systems. To address this calibration need, satellite at-sensor radiance values were compared to those estimated by each independent team member to determine the sensor's radiometric accuracy. The combined results of this evaluation provide the user community with an independent assessment of these commercially available high spatial resolution sensors' absolute calibration values.

  12. A new method for spatial resolution enhancement of hyperspectral images using sparse coding and linear spectral unmixing

    NASA Astrophysics Data System (ADS)

    Hashemi, Nezhad Z.; Karami, A.

    2015-10-01

    Hyperspectral images (HSI) have high spectral and low spatial resolutions. However, multispectral images (MSI) usually have low spectral and high spatial resolutions. In various applications HSI with high spectral and spatial resolutions are required. In this paper, a new method for spatial resolution enhancement of HSI using high resolution MSI based on sparse coding and linear spectral unmixing (SCLSU) is introduced. In the proposed method (SCLSU), high spectral resolution features of HSI and high spatial resolution features of MSI are fused. In this case, the sparse representation of some high resolution MSI and linear spectral unmixing (LSU) model of HSI and MSI is simultaneously used in order to construct high resolution HSI (HRHSI). The fusion process of HSI and MSI is formulated as an ill-posed inverse problem. It is solved by the Split Augmented Lagrangian Shrinkage Algorithm (SALSA) and an orthogonal matching pursuit (OMP) algorithm. Finally, the proposed algorithm is applied to the Hyperion and ALI datasets. Compared with the other state-of-the-art algorithms such as Coupled Nonnegative Matrix Factorization (CNMF) and local spectral unmixing, the SCLSU has significantly increased the spatial resolution and in addition the spectral content of HSI is well maintained.

  13. A spatial-temporal Hopfield neural network approach for super-resolution land cover mapping with multi-temporal different resolution remotely sensed images

    NASA Astrophysics Data System (ADS)

    Li, Xiaodong; Ling, Feng; Du, Yun; Feng, Qi; Zhang, Yihang

    2014-07-01

    The mixed pixel problem affects the extraction of land cover information from remotely sensed images. Super-resolution mapping (SRM) can produce land cover maps with a finer spatial resolution than the remotely sensed images, and reduce the mixed pixel problem to some extent. Traditional SRMs solely adopt a single coarse-resolution image as input. Uncertainty always exists in resultant fine-resolution land cover maps, due to the lack of information about detailed land cover spatial patterns. The development of remote sensing technology has enabled the storage of a great amount of fine spatial resolution remotely sensed images. These data can provide fine-resolution land cover spatial information and are promising in reducing the SRM uncertainty. This paper presents a spatial-temporal Hopfield neural network (STHNN) based SRM, by employing both a current coarse-resolution image and a previous fine-resolution land cover map as input. STHNN considers the spatial information, as well as the temporal information of sub-pixel pairs by distinguishing the unchanged, decreased and increased land cover fractions in each coarse-resolution pixel, and uses different rules in labeling these sub-pixels. The proposed STHNN method was tested using synthetic images with different class fraction errors and real Landsat images, by comparing with pixel-based classification method and several popular SRM methods including pixel-swapping algorithm, Hopfield neural network based method and sub-pixel land cover change mapping method. Results show that STHNN outperforms pixel-based classification method, pixel-swapping algorithm and Hopfield neural network based model in most cases. The weight parameters of different STHNN spatial constraints, temporal constraints and fraction constraint have important functions in the STHNN performance. The heterogeneity degree of the previous map and the fraction images errors affect the STHNN accuracy, and can be served as guidances of selecting the

  14. Current source imaging for high spatial resolution magnetocardiography in normal and abnormal rat cardiac muscles

    NASA Astrophysics Data System (ADS)

    Uchida, S.; Iramina, K.; Goto, K.; Ueno, S.

    2000-05-01

    The purpose of our study was to identify the current source produced by acute ischemia and infarction. We measured magnetocardiograms (MCG) and electrocardiograms (ECG) of five male rats using a high-resolution dc superconducting quantum interference device gradiometer in a magnetically shielded room after performing coronary artery occlusion. The spatial resolution of the detecting magnetic field of our system is higher than the typical system, thus permitting the measurement of magnetic fields in small animals. Distribution of the magnetic fields B(t) and distribution of |rot B(t)|, which corresponded to the distribution of the current source, were imaged by 12-channel MCGs. As a result, the distribution of current source changes in the affected area of the myocardium during the ST segment, and amplitude of the peak significantly increased after occlusion. Our system can be used to help clarify the mechanism of the ST shift related to severe heart disease.

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

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  16. An advanced image processing method to improve the spatial resolution of ion radiographies.

    PubMed

    Krah, N; Testa, M; Brons, S; Jäkel, O; Parodi, K; Voss, B; Rinaldi, I

    2015-11-01

    We present an optimization method to improve the spatial resolution and the water equivalent thickness (WET) accuracy of ion radiographies. The method is designed for imaging systems measuring for each actively scanned beam spot the lateral position of the pencil beam and at the same time the Bragg curve (behind the target) in discrete steps without relying on tracker detectors to determine the ion trajectory before and after the irradiated volume. Specifically, the method was used for an imaging set-up consisting of a stack of 61 parallel-plate ionization chambers (PPIC) interleaved with absorber plates of polymethyl methacrylate (PMMA) working as a range telescope. The method uses not only the Bragg peak position, but approximates the entire measured Bragg curve as a superposition of differently shifted Bragg curves. Their relative weights allow to reconstruct the distribution of thickness around each scan spot of a heterogeneous phantom. The approach also allows merging the ion radiography with the geometric information of a co-registered x-ray radiography in order to increase its spatial resolution. The method was tested using Monte Carlo simulated and experimental proton radiographies of a PMMA step phantom and an anthropomorphic head phantom. For the step phantom, the effective spatial resolution was found to be 6 and 4 times higher than the nominal resolution for the simulated and experimental radiographies, respectively. For the head phantom, a gamma index was calculated to quantify the conformity of the simulated proton radiographies with a digitally reconstructed radiography (DRR) obtained from an x-ray CT and properly converted into WET. For a distance-to-agreement (DTA) of 2.5 mm and a relative WET difference (RWET) of 2.5%, the passing ratio was 100%/85% for the optimized/non-optimized case, respectively. When the optimized proton radiography was merged with the co-registered DRR, the passing ratio was 100% at DTA  =  1.3 mm and RWET

  17. An advanced image processing method to improve the spatial resolution of ion radiographies

    NASA Astrophysics Data System (ADS)

    Krah, N.; Testa, M.; Brons, S.; Jäkel, O.; Parodi, K.; Voss, B.; Rinaldi, I.

    2015-11-01

    We present an optimization method to improve the spatial resolution and the water equivalent thickness (WET) accuracy of ion radiographies. The method is designed for imaging systems measuring for each actively scanned beam spot the lateral position of the pencil beam and at the same time the Bragg curve (behind the target) in discrete steps without relying on tracker detectors to determine the ion trajectory before and after the irradiated volume. Specifically, the method was used for an imaging set-up consisting of a stack of 61 parallel-plate ionization chambers (PPIC) interleaved with absorber plates of polymethyl methacrylate (PMMA) working as a range telescope. The method uses not only the Bragg peak position, but approximates the entire measured Bragg curve as a superposition of differently shifted Bragg curves. Their relative weights allow to reconstruct the distribution of thickness around each scan spot of a heterogeneous phantom. The approach also allows merging the ion radiography with the geometric information of a co-registered x-ray radiography in order to increase its spatial resolution. The method was tested using Monte Carlo simulated and experimental proton radiographies of a PMMA step phantom and an anthropomorphic head phantom. For the step phantom, the effective spatial resolution was found to be 6 and 4 times higher than the nominal resolution for the simulated and experimental radiographies, respectively. For the head phantom, a gamma index was calculated to quantify the conformity of the simulated proton radiographies with a digitally reconstructed radiography (DRR) obtained from an x-ray CT and properly converted into WET. For a distance-to-agreement (DTA) of 2.5 mm and a relative WET difference (RWET) of 2.5%, the passing ratio was 100%/85% for the optimized/non-optimized case, respectively. When the optimized proton radiography was merged with the co-registered DRR, the passing ratio was 100% at DTA  =  1.3 mm and RWET

  18. Subsurface imaging of silicon nanowire circuits and iron oxide nanoparticles with sub-10 nm spatial resolution.

    PubMed

    Perrino, A P; Ryu, Y K; Amo, C A; Morales, M P; Garcia, R

    2016-07-01

    Non-destructive subsurface characterization of nanoscale structures and devices is of significant interest in nanolithography and nanomanufacturing. In those areas, the accurate location of the buried structures and their nanomechanical properties are relevant for optimization of the nanofabrication process and the functionality of the system. Here we demonstrate the capabilities of bimodal and trimodal force microscopy for imaging silicon nanowire devices buried under an ultrathin polymer film. We resolve the morphology and periodicities of silicon nanowire pairs. We report a spatial resolution in the sub-10 nm range for nanostructures buried under a 70 nm thick polymer film. By using numerical simulations we explain the role of the excited modes in the subsurface imaging process. Independent of the bimodal or trimodal atomic force microscopy approach, the fundamental mode is the most suitable for tracking the topography while the higher modes modulate the interaction of the tip with the buried nanostructures and provide subsurface contrast. PMID:27232523

  19. Subsurface imaging of silicon nanowire circuits and iron oxide nanoparticles with sub-10 nm spatial resolution

    NASA Astrophysics Data System (ADS)

    Perrino, A. P.; Ryu, Y. K.; Amo, C. A.; Morales, M. P.; Garcia, R.

    2016-07-01

    Non-destructive subsurface characterization of nanoscale structures and devices is of significant interest in nanolithography and nanomanufacturing. In those areas, the accurate location of the buried structures and their nanomechanical properties are relevant for optimization of the nanofabrication process and the functionality of the system. Here we demonstrate the capabilities of bimodal and trimodal force microscopy for imaging silicon nanowire devices buried under an ultrathin polymer film. We resolve the morphology and periodicities of silicon nanowire pairs. We report a spatial resolution in the sub-10 nm range for nanostructures buried under a 70 nm thick polymer film. By using numerical simulations we explain the role of the excited modes in the subsurface imaging process. Independent of the bimodal or trimodal atomic force microscopy approach, the fundamental mode is the most suitable for tracking the topography while the higher modes modulate the interaction of the tip with the buried nanostructures and provide subsurface contrast.

  20. Radiofrequency field inhomogeneity compensation in high spatial resolution magnetic resonance spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Passeri, Alessandro; Mazzuca, Stefano; Del Bene, Veronica

    2014-06-01

    Clinical magnetic resonance spectroscopy imaging (MRSI) is a non-invasive functional technique, whose mathematical framework falls into the category of linear inverse problems. However, its use in medical diagnostics is hampered by two main problems, both linked to the Fourier-based technique usually implemented for spectra reconstruction: poor spatial resolution and severe blurring in the spatial localization of the reconstructed spectra. Moreover, the intrinsic ill-posedness of the MRSI problem might be worsened by (i) spatially dependent distortions of the static magnetic field (B0) distribution, as well as by (ii) inhomogeneity in the power deposition distribution of the radiofrequency magnetic field (B1). Among several alternative methods, slim (Spectral Localization by IMaging) and bslim (B0 compensated slim) are reconstruction algorithms in which a priori information concerning the spectroscopic target is introduced into the reconstruction kernel. Nonetheless, the influence of the B1 field, particularly when its operating wavelength is close to the size of the human organs being studied, continues to be disregarded. starslim (STAtic and Radiofrequency-compensated slim), an evolution of the slim and bslim methods, is therefore proposed, in which the transformation kernel also includes the B1 field inhomogeneity map, thus allowing almost complete 3D modelling of the MRSI problem. Moreover, an original method for the experimental determination of the B1 field inhomogeneity map specific to the target under evaluation is also included. The compensation capabilities of the proposed method have been tested and illustrated using synthetic raw data reproducing the human brain.

  1. High Spatial Resolution Investigations of Microchannel Plate Imaging Properties for UV Detectors

    NASA Technical Reports Server (NTRS)

    Siegmund, Oswald

    1996-01-01

    Microchannel plate (MCP) photon counting detectors are currently being used with great success on many of the recent NASA/ESA ultraviolet (UV) astrophysics missions that make observations in the 1OO A - 1600 A range. These include HUT, the Wide Field Camera on ROSAT, EUVE, ALEXIS, ORFEUS, and SOHO. These devices have also been chosen to fly on future UV astrophysics missions such as FUSE, FUVITA, IMAGE, and both the HST STIS and Advanced Camera instruments. During the period of this award we have fabricated a dual-chamber vacuum test facility to carry out laboratory testing of detector resolution, image stability and linearity, and flat field performance to enable us to characterize the performance of MCPs and their associated read-out architectures. We have also fabricated and tested a laboratory 'test-bed' delay line detector, which can accommodate MCP's with a wide range of formats and run at high data rates, to continue our studies of MCP image fixed pattern noise, and particularly for new small pore MCP's which have recently come onto the market. These tests were mainly focussed on the assessment of cross delay-line (XDL) and double delay line (DDL) anode read-out schemes, with particular attention being focussed on flat-field and spatial resolution performance.

  2. Development of a high spatial resolution neutron imaging system and performance evaluation

    NASA Astrophysics Data System (ADS)

    Cao, Lei

    The combination of a scintillation screen and a charged coupled device (CCD) camera is a digitized neutron imaging technology that has been widely employed for research and industry application. The maximum of spatial resolution of scintillation screens is in the range of 100 mum and creates a bottleneck for the further improvement of the overall system resolution. In this investigation, a neutron sensitive micro-channel plate (MCP) detector with pore pitch of 11.4 mum is combined with a cooled CCD camera with a pixel size of 6.8 mum to provide a high spatial resolution neutron imaging system. The optical path includes a high reflection front surface mirror for keeping the camera out of neutron beam and a macro lens for achieving the maximum magnification that could be achieved. All components are assembled into an aluminum light tight box with heavy radiation shielding to protect the camera as well as to provide a dark working condition. Particularly, a remote controlled stepper motor is also integrated into the system to provide on-line focusing ability. The best focus is guaranteed through use of an algorithm instead of perceptual observation. An evaluation routine not previously utilized in the field of neutron radiography is developed in this study. Routines like this were never previously required due to the lower resolution of other systems. Use of the augulation technique to obtain presampled MTF addresses the problem of aliasing associated with digital sampling. The determined MTF agrees well with the visual inspection of imaging a testing target. Other detector/camera combinations may be integrated into the system and their performances are also compared. The best resolution achieved by the system at the TRIGA Mark II reactor at the University of Texas at Austin is 16.2 lp/mm, which is equivalent to a minimum resolvable spacing of 30 mum. The noise performance of the device is evaluated in terms of the noise power spectrum (NPS) and the detective quantum

  3. HIGH SPATIAL RESOLUTION SURVEY OF GRAIN SIZE INFORMATION ON RIVER BED BY IMAGE PROCESSING

    NASA Astrophysics Data System (ADS)

    Ohashi, Keisuke; Ihara, Kazuki; Yasuda, Shingo

    We tried a method of grain sizing by image processing which is available to survey and analyze in short time. The high-efficiency method actualizes high spatial resolution information of grain size distribution. Thus, the information has a vailability to express a situation of stream flow better than traditional grain sizing methods. For this reason, we paid attention to 50 m reservoir area upper from the check dam in mountainous region and surveyed the grain distribution at 26 sites and river channel landform. The grain sizing by image processing provided the appropriate result qualitatively. Moreover we estimated the critical diameter of moving from hydraulic information simultaneously. A qualitative appropriate result is showed less than 50 mm error as a result, however, quantitative response is not found between the critical diameter of moving and the grain size distribution surveyed. Meanwhile,the different grain sizing methods that are image processing and traditional sieving are used to cover the bilateral weak point. Thereby, a peak of grain existence probability is found in the threshold diameter between image processing and sieving. This result indicates that it is necessary to change the threshold diameter much larger than the limit of image processing grain sizing.

  4. The Geospectral Camera: a Compact and Geometrically Precise Hyperspectral and High Spatial Resolution Imager

    NASA Astrophysics Data System (ADS)

    Delauré, B.; Michiels, B.; Biesemans, J.; Livens, S.; Van Achteren, T.

    2013-04-01

    Small unmanned aerial vehicles are increasingly being employed for environmental monitoring at local scale, which drives the demand for compact and lightweight spectral imagers. This paper describes the geospectral camera, which is a novel compact imager concept. The camera is built around an innovative detector which has two sensor elements on a single chip and therefore offers the functionality of two cameras within the volume of a single one. The two sensor elements allow the camera to derive both spectral information as well as geometric information (high spatial resolution imagery and a digital surface model) of the scene of interest. A first geospectral camera prototype has been developed. It uses a linear variable optical filter which is installed in front of one of the two sensors of the MEDUSA CMOS imager chip. A accompanying software approach has been developed which exploits the simultaneous information of the two sensors in order to extract an accurate spectral image product. This method has been functionally demonstrated by applying it on image data acquired during an airborne acquisition.

  5. Improving the Spatial Resolution of Neutron Imaging at Paul Scherrer Institut - The Neutron Microscope Project

    NASA Astrophysics Data System (ADS)

    Trtik, Pavel; Hovind, Jan; Grünzweig, Christian; Bollhalder, Alex; Thominet, Vincent; David, Christian; Kaestner, Anders; Lehmann, Eberhard H.

    Here we present results stemming from the first prototype of the Neutron Microscope instrument at Paul ScherrerInstitut (PSI). The instrument is based on a very thin gadolinium oxysulfide (Gd2O2S:Tb+) scintillator screen and a magnifying optics. The Neutron Microscope prototype has been tested at the ICON and the BOA beamlines at PSI and sub-10 μm features can be clearly resolved on a focussed ion beam (FIB) enhance test object - a gadolinium-based Siemens star. The spatial resolution of the images of the gadolinium-based Siemensstar assessed by Fourier ring correlation was about 7.6 μm. The outlook for future improvement of the Neutron Microscope system is presented.

  6. Optoelectronic Switching of a Carbon Nanotube Chiral Junction Imaged with Nanometer Spatial Resolution.

    PubMed

    Nienhaus, Lea; Wieghold, Sarah; Nguyen, Duc; Lyding, Joseph W; Scott, Gregory E; Gruebele, Martin

    2015-11-24

    Chiral junctions of carbon nanotubes have the potential of serving as optically or electrically controllable switches. To investigate optoelectronic tuning of a chiral junction, we stamp carbon nanotubes onto a transparent gold surface and locate a tube with a semiconducting-metallic junction. We image topography, laser absorption at 532 nm, and measure I-V curves of the junction with nanometer spatial resolution. The bandgaps on both sides of the junction depend on the applied tip field (Stark effect), so the semiconducting-metallic nature of the junction can be tuned by varying the electric field from the STM tip. Although absolute field values can only be estimated because of the unknown tip geometry, the bandgap shifts are larger than expected from the tip field alone, so optical rectification of the laser and carrier generation by the laser must also affect the bandgap switching of the chiral junction. PMID:26348682

  7. A comparative study of different level interpolations for improving spatial resolution in diffusion tensor imaging.

    PubMed

    Yang, Feng; Zhu, Yue-Min; Luo, Jian-Hua; Robini, Marc; Liu, Jie; Croisille, Pierre

    2014-07-01

    This paper studies and evaluates the feasibility and the performance of different level interpolations for improving spatial resolution of diffusion tensor magnetic resonance imaging (DT-MRI or DTI). In particular, the following techniques are investigated: anisotropic interpolation operating on scalar gray-level images, log-Euclidean interpolation method, and the quaternion interpolation method, which operate on diffusion tensor fields. The performance is evaluated both qualitatively and quantitatively using criteria such as tensor determinant, fractional anisotropy (FA), mean diffusivity (MD), fiber length, etc. We conclude that tensor field interpolations allow avoiding undesirable swelling effect in DTI, which is not the case with scalar gray-level interpolation, and that scalar gray-level image interpolation and log-Euclidean tensor field interpolation suffer from decrease in FA and MD, which may mislead the interpretation of the clinical parameters FA and MD. In contrast, the quaternion tensor field interpolation avoids such FA and MD decrease, which suggests its use for clinical applications. PMID:25014936

  8. High spatial and temporal resolution wide-field imaging of neuron activity using quantum NV-diamond

    PubMed Central

    Hall, L. T.; Beart, G. C. G.; Thomas, E. A.; Simpson, D. A.; McGuinness, L. P.; Cole, J. H.; Manton, J. H.; Scholten, R. E.; Jelezko, F.; Wrachtrup, Jörg; Petrou, S.; Hollenberg, L. C. L.

    2012-01-01

    A quantitative understanding of the dynamics of biological neural networks is fundamental to gaining insight into information processing in the brain. While techniques exist to measure spatial or temporal properties of these networks, it remains a significant challenge to resolve the neural dynamics with subcellular spatial resolution. In this work we consider a fundamentally new form of wide-field imaging for neuronal networks based on the nanoscale magnetic field sensing properties of optically active spins in a diamond substrate. We analyse the sensitivity of the system to the magnetic field generated by an axon transmembrane potential and confirm these predictions experimentally using electronically-generated neuron signals. By numerical simulation of the time dependent transmembrane potential of a morphologically reconstructed hippocampal CA1 pyramidal neuron, we show that the imaging system is capable of imaging planar neuron activity non-invasively at millisecond temporal resolution and micron spatial resolution over wide-fields. PMID:22574249

  9. Imaging at high spatial resolution: Soft x-ray microscopy to 15nm

    SciTech Connect

    Attwood, D.; Chao, W.; Anderson, E.; Liddle, J.A.; Harteneck, B.; Fischer, P.; Schneider, G.; Le Gros, M.; Larabell, C.

    2006-04-05

    Soft x-ray microscopy has now achieved 15 nm spatial resolution with new zone plates and bending magnet radiation. Combined with elemental sensitivity and flexible sample environment (applied magnetic or electric fields, wet samples, windows, overcoatings) this emerges as a valuable tool for nanoscience and nanotechnology, complimenting common electron and scanning tip microscopies. In this presentation we describe recent advances in spatial resolution, expectations for the near future, and applications to magnetic materials, bio-tomography, etc.

  10. Observation and analysis of microcirculation using high-spatial-resolution image detectors and synchrotron radiation

    NASA Astrophysics Data System (ADS)

    Umetani, Keiji; Yagi, Naoto; Suzuki, Yoshio; Ogasawara, Yasuo; Kajiya, Fumihiko; Matsumoto, Takeshi; Tachibana, Hiroyuki; Goto, Masami; Yamashita, Takenori; Imai, Shigeki; Kajihara, Yasumasa

    2000-04-01

    A microangiography system using monochromatized synchrotron radiation has been investigated as a diagnostic tool for circulatory disorders and early stage malignant tumors. The monochromatized X-rays with energies just above the contrast agent K-absorption edge energy can produce the highest contrast image of the contrast agent in small blood vessels. At SPring-8, digital microradiography with 6 - 24 micrometer pixel sizes has been carried out using two types of detectors designed for X-ray indirect and direct detection. The indirect-sensing detectors are fluorescent-screen optical-lens coupling systems using a high-sensitivity pickup-tube camera and a CCD camera. An X-ray image on the fluorescent screen is focused on the photoconductive layer of the pickup tube and the photosensitive area of the CCD by a small F number lens. The direct-sensing detector consists of an X-ray direct- sensing pickup tube with a beryllium faceplate for X-ray incidence to the photoconductive layer. Absorbed X-rays in the photoconductive layer are directly converted to photoelectrons and then signal charges are readout by electron beam scanning. The direct-sensing detector was expected to have higher spatial resolution in comparison with the indict-sensing detectors. Performance of the X-ray image detectors was examined at the bending magnet beamline BL20B2 using monochromatized X-ray at SPring-8. Image signals from the camera are converted into digital format by an analog-to- digital converter and stored in a frame memory with image format of 1024 X 1024 pixels. In preliminary experiments, tumor vessel specimens using barium contrast agent were prepared for taking static images. The growth pattern of tumor-induced vessels was clearly visualized. Heart muscle specimens were prepared for imaging of 3-dimensional microtomography using the fluorescent-screen CCD camera system. The complex structure of small blood vessels with diameters of 30 - 40 micrometer was visualized as a 3

  11. Low-Z target optimization for spatial resolution improvement in megavoltage imaging

    SciTech Connect

    Connell, Tanner; Robar, James L.

    2010-01-15

    Purpose: Recently, several authors have shown contrast improvements in megavoltage portal imaging and cone-beam computed tomography using low atomic number (Z) targets. This work compliments previous studies by investigating the effects of varying different beam production parameters including target atomic number, target thickness, and incident electron energy on spatial resolution. Methods: Target materials of beryllium, aluminum, and tungsten were investigated over a range of thicknesses between 10% and 100% of the continuous slowing down approximation range of electrons. Incident electron kinetic energies of 4.5 and 7.0 MeV were used, in conjunction with custom targets installed above the carousel of a modern radiotherapy linear accelerator. Monte Carlo simulations of the accelerator were constructed and compared to the experimental results. Results: The results showed that thinner targets, as well higher incident electron energies, generally produce more favorable modulation transfer function (MTF) curves. Due to an MTF dependence of the detector system on the photon energy, the experimental results showed that low-Z targets produced superior MTF curves. Simulations showed 14.5% and 21.5% increases in f{sub 50} for the 7.0 and 4.5 MeV targets (Al; 60%R{sub %CSDA}), respectively, when moved from the carousel to the location of the clinical target. f{sub 50} values for the custom targets were compared to the clinical 6 MV beam and were found to be between 10.4% lower (4.5 MeV/W) and 15.5% higher (7.0 MeV/Be). Conclusions: Integration of low-Z external targets into the treatment head of a medical linear was achieved with only minor modifications. It was shown that reasonably high resolution images on par or better than those acquired with the clinical 6 MV beam can be achieved using external low-Z targets.

  12. Miniaturization of high spectral spatial resolution hyperspectral imagers on unmanned aerial systems

    NASA Astrophysics Data System (ADS)

    Hill, Samuel L.; Clemens, Peter

    2015-06-01

    Traditional airborne environmental monitoring has frequently deployed hyperspectral imaging as a leading tool for characterizing and analyzing a scene's critical spectrum-based signatures for applications in agriculture genomics and crop health, vegetation and mineral monitoring, and hazardous material detection. As the acceptance of hyperspectral evaluation grows in the airborne community, there has been a dramatic trend in moving the technology from use on midsize aircraft to Unmanned Aerial Systems (UAS). The use of UAS accomplishes a number of goals including the reduction in cost to run multiple seasonal evaluations over smaller but highly valuable land-areas, the ability to use frequent data collections to make rapid decisions on land management, and the improvement of spatial resolution by flying at lower altitudes (<500 ft.). Despite this trend, there are several key parameters affecting the use of traditional hyperspectral instruments in UAS with payloads less than 10 lbs. where size, weight and power (SWAP) are critical to how high and how far a given UAS can fly. Additionally, on many of the light-weight UAS, users are frequently trying to capture data from one or more instruments to augment the hyperspectral data collection, thus reducing the amount of SWAP available to the hyperspectral instrumentation. The following manuscript will provide an analysis on a newly-developed miniaturized hyperspectral imaging platform, the Nano-Hyperspec®, which provides full hyperspectral resolution and traditional hyperspectral capabilities without sacrificing performance to accommodate the decreasing SWAP of smaller and smaller UAS platforms. The analysis will examine the Nano-Hyperspec flown in several UAS airborne environments and the correlation of the systems data with LiDAR and other GIS datasets.

  13. Reprocessing the Historical Satellite Passive Microwave Record at Enhanced Spatial Resolutions using Image Reconstruction

    NASA Astrophysics Data System (ADS)

    Hardman, M.; Brodzik, M. J.; Long, D. G.; Paget, A. C.; Armstrong, R. L.

    2015-12-01

    Beginning in 1978, the satellite passive microwave data record has been a mainstay of remote sensing of the cryosphere, providing twice-daily, near-global spatial coverage for monitoring changes in hydrologic and cryospheric parameters that include precipitation, soil moisture, surface water, vegetation, snow water equivalent, sea ice concentration and sea ice motion. Currently available global gridded passive microwave data sets serve a diverse community of hundreds of data users, but do not meet many requirements of modern Earth System Data Records (ESDRs) or Climate Data Records (CDRs), most notably in the areas of intersensor calibration, quality-control, provenance and consistent processing methods. The original gridding techniques were relatively primitive and were produced on 25 km grids using the original EASE-Grid definition that is not easily accommodated in modern software packages. Further, since the first Level 3 data sets were produced, the Level 2 passive microwave data on which they were based have been reprocessed as Fundamental CDRs (FCDRs) with improved calibration and documentation. We are funded by NASA MEaSUREs to reprocess the historical gridded data sets as EASE-Grid 2.0 ESDRs, using the most mature available Level 2 satellite passive microwave (SMMR, SSM/I-SSMIS, AMSR-E) records from 1978 to the present. We have produced prototype data from SSM/I and AMSR-E for the year 2003, for review and feedback from our Early Adopter user community. The prototype data set includes conventional, low-resolution ("drop-in-the-bucket" 25 km) grids and enhanced-resolution grids derived from the two candidate image reconstruction techniques we are evaluating: 1) Backus-Gilbert (BG) interpolation and 2) a radiometer version of Scatterometer Image Reconstruction (SIR). We summarize our temporal subsetting technique, algorithm tuning parameters and computational costs, and include sample SSM/I images at enhanced resolutions of up to 3 km. We are actively

  14. Analysis of computed tomographic imaging spectrometers. I. Spatial and spectral resolution.

    PubMed

    Hagen, Nathan; Dereniak, Eustace L

    2008-10-01

    Computed tomographic imaging spectrometers measure the spectrally resolved image of an object scene in an entirely different manner from traditional whisk-broom or push-broom systems, and thus their noise behavior and data artifacts are unfamiliar. We review computed tomographic imaging spectrometry (CTIS) measurement systems and analyze their performance, with the aim of providing a vocabulary for discussing resolution in CTIS instruments, by illustrating the artifacts present in their reconstructed data and contributing a rule-of-thumb measure of their spectral resolution. We also show how the data reconstruction speed can be improved, at no cost in reconstruction quality, by ignoring redundant projections within the measured raw images. PMID:18830288

  15. HIGH SPATIAL-RESOLUTION IMAGING OF TE INCLUSIONS IN CZT MATERIAL.

    SciTech Connect

    CAMARDA, G.S.; BOLOTNIKOV, A.E.; CARINI, G.A.; CUI, Y.; KOHMAN, K.T.; LI, L.; JAMES, R.B.

    2006-08-13

    We present new results from our studies of defects in current single-crystal CdZnTe material. Our previous measurements, carried out on thin ({approx}1 mm) and long (>12 mm) CZT detectors, indicated that small (1-20 {micro}m) Te inclusions can significantly degrade the device's energy resolution and detection efficiency. We are conducting detailed studies of the effects of Te inclusions by employing different characterization techniques with better spatial resolution, such as quantitative fluorescence mapping, X-ray micro-diffraction, and TEM. Also, IR microscopy and gamma-mapping with pulse-shape analysis with higher spatial resolution generated more accurate results in the areas surrounding the micro-defects (Te inclusions). Our results reveal how the performance of CdZnTe detectors is influenced by Te inclusions, such as their spatial distribution, concentration, and size. We also discuss a model of charge transport through areas populated with Te inclusions.

  16. Cost-effective infrared thermography protocol for 40 μm spatial resolution quantitative microelectronic imaging

    NASA Astrophysics Data System (ADS)

    Boué, Christine; Fournier, Danièle

    2006-06-01

    In this article, we will show that the absolute temperature of electrical components under test can be measured with an infrared camera. An easy and cost-effective modification of the optical set-up and a software correction of the artefacts induced by the modification of the aperture of the objective allow to improve the spatial resolution. Calibrations with a Peltier system allow to obtain quantitative measurements. Consequently, it becomes easy to obtain a mapping of the absolute temperature of the surface of an integrated circuit from its infrared radiation, independently of its surface emissivity with a spatial resolution better than 40 μm.

  17. DigiPET: sub-millimeter spatial resolution small-animal PET imaging using thin monolithic scintillators.

    PubMed

    España, Samuel; Marcinkowski, Radoslaw; Keereman, Vincent; Vandenberghe, Stefaan; Van Holen, Roel

    2014-07-01

    A new preclinical PET system based on dSiPMs, called DigiPET, is presented. The system is based on thin monolithic scintillation crystals and exhibits superior spatial resolution at low-cost compared to systems based on pixelated crystals. Current dedicated small-rodent PET scanners have a spatial resolution in the order of 1 mm. Most of them have a large footprint, requiring considerable laboratory space. For rodent brain imaging, a PET scanner with sub-millimeter resolution is desired. To achieve this, crystals with a pixel pitch down to 0.5 mm have been used. However, fine pixels are difficult to produce and will render systems expensive. In this work, we present the first results with a high-resolution preclinical PET scanner based on thin monolithic scintillators and a large solid angle. The design is dedicated to rat-brain imaging and therefore has a very compact geometry. Four detectors were placed in a square arrangement with a distance of 34.5 mm between two opposing detector modules, defining a field of view (FOV) of 32 × 32 × 32 mm(3). Each detector consists of a thin monolithic LYSO crystal of 32 × 32 × 2 mm(3) optically coupled to a digital silicon photomultiplier (dSiPM). Event positioning within each detector was obtained using the maximum likelihood estimation (MLE) method. To evaluate the system performance, we measured the energy resolution, coincidence resolving time (CRT), sensitivity and spatial resolution. The image quality was evaluated by acquiring a hot-rod phantom filled with (18)F-FDG and a rat head one hour after an (18)F-FDG injection. The MLE yielded an average intrinsic spatial resolution on the detector of 0.54 mm FWHM. We obtained a CRT of 680 ps and an energy resolution of 18% FWHM at 511 keV. The sensitivity and spatial resolution obtained at the center of the FOV were 6.0 cps kBq(-1) and 0.7 mm, respectively. In the reconstructed images of the hot-rod phantom, hot rods down to 0.7 mm can be discriminated

  18. Photoacoustic radar phase-filtered spatial resolution and co-registered ultrasound image enhancement for tumor detection

    PubMed Central

    Dovlo, Edem; Lashkari, Bahman; Mandelis, Andreas; Shi, Wei; Liu, Fei-Fei

    2015-01-01

    Co-registered ultrasound (US) and frequency-domain photoacoustic radar (FD-PAR) imaging is reported for the first time in this paper. The merits of ultrasound and cross-correlation (radar) frequency-domain photoacoustic imaging are leveraged for accurate tumor detection. Commercial US imagers possess sophisticated, optimized software for rapid image acquisition that could dramatically speed-up PA imaging. The PAR image generated from the amplitude of the cross-correlation between detected and input signals was filtered by the standard deviation (SD) of the phase of the correlation signal, resulting in strong improvement of image spatial resolution, signal-to-noise ratio (SNR) and contrast. Application of phase-mediated image improvement is illustrated by imaging a cancer cell-injected mouse. A 14–15 dB SNR gain was recorded for the phase-filtered image compared to the amplitude and phase independently, while ~340 μm spatial resolution was seen for the phase PAR image compared to ~840 μm for the amplitude image. PMID:25798321

  19. Influence of spatial and temporal coherences on atomic resolution high angle annular dark field imaging.

    PubMed

    Beyer, Andreas; Belz, Jürgen; Knaub, Nikolai; Jandieri, Kakhaber; Volz, Kerstin

    2016-10-01

    Aberration-corrected (scanning) transmission electron microscopy ((S)TEM) has become a widely used technique when information on the chemical composition is sought on an atomic scale. To extract the desired information, complementary simulations of the scattering process are inevitable. Often the partial spatial and temporal coherences are neglected in the simulations, although they can have a huge influence on the high resolution images. With the example of binary gallium phosphide (GaP) we elucidate the influence of the source size and shape as well as the chromatic aberration on the high angle annular dark field (HAADF) intensity. We achieve a very good quantitative agreement between the frozen phonon simulation and experiment for different sample thicknesses when a Lorentzian source distribution is assumed and the effect of the chromatic aberration is considered. Additionally the influence of amorphous layers introduced by the preparation of the TEM samples is discussed. Taking into account these parameters, the intensity in the whole unit cell of GaP, i.e. at the positions of the different atomic columns and in the region between them, is described correctly. With the knowledge of the decisive parameters, the determination of the chemical composition of more complex, multinary materials becomes feasible. PMID:27391526

  20. High Spatial Resolution Imaging Mass Spectrometry of Human Optic Nerve Lipids and Proteins

    NASA Astrophysics Data System (ADS)

    Anderson, David M. G.; Spraggins, Jeffrey M.; Rose, Kristie L.; Schey, Kevin L.

    2015-06-01

    The human optic nerve carries signals from the retina to the visual cortex of the brain. Each optic nerve is comprised of approximately one million nerve fibers that are organized into bundles of 800-1200 fibers surrounded by connective tissue and supportive glial cells. Damage to the optic nerve contributes to a number of blinding diseases including: glaucoma, neuromyelitis optica, optic neuritis, and neurofibromatosis; however, the molecular mechanisms of optic nerve damage and death are incompletely understood. Herein we present high spatial resolution MALDI imaging mass spectrometry (IMS) analysis of lipids and proteins to define the molecular anatomy of the human optic nerve. The localization of a number of lipids was observed in discrete anatomical regions corresponding to myelinated and unmyelinated nerve regions as well as to supporting connective tissue, glial cells, and blood vessels. A protein fragment from vimentin, a known intermediate filament marker for astrocytes, was observed surrounding nerved fiber bundles in the lamina cribrosa region. S100B was also found in supporting glial cell regions in the prelaminar region, and the hemoglobin alpha subunit was observed in blood vessel areas. The molecular anatomy of the optic nerve defined by MALDI IMS provides a firm foundation to study biochemical changes in blinding human diseases.

  1. Real space soft x-ray imaging at 10 nm spatial resolution

    SciTech Connect

    Chao, Weilun; Fischer, Peter; Tyliszczak, T.; Rekawa, Senajith; Anderson, Erik; Naulleau, Patrick

    2011-04-24

    Using Fresnel zone plates made with our robust nanofabrication processes, we have successfully achieved 10 nm spatial resolution with soft x-ray microscopy. The result, obtained with both a conventional full-field and scanning soft x-ray microscope, marks a significant step forward in extending the microscopy to truly nanoscale studies.

  2. Extraction of residential information from high-spatial resolution image integrated with upscaling methods and object multi-features

    NASA Astrophysics Data System (ADS)

    Dong, Lixin; Wu, Bingfang

    2007-11-01

    Monitoring residential areas at a regional scale, and even at a global scale, has become an increasingly important topic. However, extraction of residential information was still a difficulty and challenging task, such as multiple usable data selection and automatic or semi-automatic techniques. In metropolitan area, such as Beijing, urban sprawl has brought enormous pressure on rural and natural environments. Given a case study, a new strategy of extracting of residential information integrating the upscaling methods and object multi-features was introduced in high resolution SPOT fused image. Multi-resolution dataset were built using upscaling methods, and optimal resolution image was selected by semi-variance analysis approach. Relevant optimal spatial resolution images were adopted for different type of residential area (city, town and rural residence). Secondly, object multi-features, including spectral information, generic shape features, class related features, and new computed features, were introduced. An efficient decision tree and Class Semantic Representation were set up based on object multi-features. And different classes of residential area were extracted from multi-resolution image. Afterwards, further discussion and comparison about improving the efficiency and accuracy of classification with the proposed approach were presented. The results showed that the optimal resolution image selected by upscaling and semi-variance method successfully decreased the heterogeneous, smoothed the noise influence, decreased computational, storage burdens and improved classification efficiency in high spatial resolution image. The Class Semantic Representation and decision tree based on object multi-features improved the overall accuracy and diminished the 'salt and pepper effect'. The new image analysis approach offered a satisfactory solution for extracting residential information quickly and efficiently.

  3. Micro-endoscope for in vivo widefield high spatial resolution fluorescent imaging

    PubMed Central

    Saunter, C D; Semprini, S.; Buckley, C.; Mullins, J; Girkin, J M

    2012-01-01

    In this paper we report the design, testing and use of a scannerless probe specifically for minimally invasive imaging of deep tissue in vivo with an epi-fluorescence modality. The probe images a 500 μm diameter field of view through a 710 μm outer diameter probe with a maximum tissue penetration depth of 15 mm specifically configured for eGFP imaging. Example results are given from imaging the pituitary gland of rats and zebrafish hearts with lateral resolution of 2.5 μm. PMID:22741074

  4. a Kernel Method Based on Topic Model for Very High Spatial Resolution (vhsr) Remote Sensing Image Classification

    NASA Astrophysics Data System (ADS)

    Wu, Linmei; Shen, Li; Li, Zhipeng

    2016-06-01

    A kernel-based method for very high spatial resolution remote sensing image classification is proposed in this article. The new kernel method is based on spectral-spatial information and structure information as well, which is acquired from topic model, Latent Dirichlet Allocation model. The final kernel function is defined as K = u1Kspec + u2Kspat + u3Kstru, in which Kspec, Kspat, Kstru are radial basis function (RBF) and u1 + u2 + u3 = 1. In the experiment, comparison with three other kernel methods, including the spectral-based, the spectral- and spatial-based and the spectral- and structure-based method, is provided for a panchromatic QuickBird image of a suburban area with a size of 900 × 900 pixels and spatial resolution of 0.6 m. The result shows that the overall accuracy of the spectral- and structure-based kernel method is 80 %, which is higher than the spectral-based kernel method, as well as the spectral- and spatial-based which accuracy respectively is 67 % and 74 %. What's more, the accuracy of the proposed composite kernel method that jointly uses the spectral, spatial, and structure information is highest among the four methods which is increased to 83 %. On the other hand, the result of the experiment also verifies the validity of the expression of structure information about the remote sensing image.

  5. Image sensors with electrically tunable spatial resolution based on liquid crystal microlens array with three-layered patterned electrode

    NASA Astrophysics Data System (ADS)

    Tong, Qing; Zhang, Xinyu; Sang, Hongshi; Zhang, Tianxu; Xie, Changsheng

    2013-10-01

    The liquid crystal (LC) device with the circle aperture electrode can be used as a convex lens. The index of refraction of the LC lens can be easily changed by the voltage signal; the arrayed LC lens can be used in the imaging sensors. Comparing with the traditional optical lens, the LC lens has a more effective architecture. In this paper, we present an imaging sensor with a new type LC structure composed of three layers of top electrodes and a joint bottom electrode, and simulating the tunable spatial resolution architecture carried out by applying voltage signal over different ITO electrode in LC lenses coupled with arrayed imaging sensors. From the result of the simulation, we can find that changing the spatial resolution by our architecture can be achieved.

  6. APD-based X-ray imaging telescope using fresnel zone plates for extremely high Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Squillante, Michael R.; Myers, Richard A.; Woodring, Mitchell; Christian, James F.; Robertson, Frank; Farrell, Richard; Kogan, Alexander I.; Tiernan, Timothy C.; Entine, Gerald

    2005-09-01

    A method for constructing an x-ray telescope with exceedingly hgh spatial resolution is to use a pair of coaxial, Fresnel zone plates aligned with an imaging x-ray detector. This combination allows the high sensitivity imaging of x-ray and gamma-ray sources ranging in energy from 1 keV to several hundred keV over a field of view of several degrees with spatial resolution of a fraction of an arc minute. We have implemented a version of such a telescope using several relatively new technologies. These include specialized techniques for constructing Fresnel zone plates from thin sheets of tungsten, a 64-element, avalanche photodiode (APD) array coupled to a matching, segmented, CsI(T1) scintillator, a new ASIC which provides 16-channels of low noise amplification, and image processing software that provides the user not only with localized intensity information, but also with localized spectral information.

  7. 3D resolution enhancement of deep-tissue imaging based on virtual spatial overlap modulation microscopy.

    PubMed

    Su, I-Cheng; Hsu, Kuo-Jen; Shen, Po-Ting; Lin, Yen-Yin; Chu, Shi-Wei

    2016-07-25

    During the last decades, several resolution enhancement methods for optical microscopy beyond diffraction limit have been developed. Nevertheless, those hardware-based techniques typically require strong illumination, and fail to improve resolution in deep tissue. Here we develop a high-speed computational approach, three-dimensional virtual spatial overlap modulation microscopy (3D-vSPOM), which immediately solves the strong-illumination issue. By amplifying only the spatial frequency component corresponding to the un-scattered point-spread-function at focus, plus 3D nonlinear value selection, 3D-vSPOM shows significant resolution enhancement in deep tissue. Since no iteration is required, 3D-vSPOM is much faster than iterative deconvolution. Compared to non-iterative deconvolution, 3D-vSPOM does not need a priori information of point-spread-function at deep tissue, and provides much better resolution enhancement plus greatly improved noise-immune response. This method is ready to be amalgamated with two-photon microscopy or other laser scanning microscopy to enhance deep-tissue resolution. PMID:27464077

  8. Particle detector spatial resolution

    DOEpatents

    Perez-Mendez, Victor

    1992-01-01

    Method and apparatus for producing separated columns of scintillation layer material, for use in detection of X-rays and high energy charged particles with improved spatial resolution. A pattern of ridges or projections is formed on one surface of a substrate layer or in a thin polyimide layer, and the scintillation layer is grown at controlled temperature and growth rate on the ridge-containing material. The scintillation material preferentially forms cylinders or columns, separated by gaps conforming to the pattern of ridges, and these columns direct most of the light produced in the scintillation layer along individual columns for subsequent detection in a photodiode layer. The gaps may be filled with a light-absorbing material to further enhance the spatial resolution of the particle detector.

  9. Regularization Designs for Uniform Spatial Resolution and Noise Properties in Statistical Image Reconstruction for 3D X-ray CT

    PubMed Central

    Cho, Jang Hwan; Fessler, Jeffrey A.

    2014-01-01

    Statistical image reconstruction methods for X-ray computed tomography (CT) provide improved spatial resolution and noise properties over conventional filtered back-projection (FBP) reconstruction, along with other potential advantages such as reduced patient dose and artifacts. Conventional regularized image reconstruction leads to spatially variant spatial resolution and noise characteristics because of interactions between the system models and the regularization. Previous regularization design methods aiming to solve such issues mostly rely on circulant approximations of the Fisher information matrix that are very inaccurate for undersampled geometries like short-scan cone-beam CT. This paper extends the regularization method proposed in [1] to 3D cone-beam CT by introducing a hypothetical scanning geometry that helps address the sampling properties. The proposed regularization designs were compared with the original method in [1] with both phantom simulation and clinical reconstruction in 3D axial X-ray CT. The proposed regularization methods yield improved spatial resolution or noise uniformity in statistical image reconstruction for short-scan axial cone-beam CT. PMID:25361500

  10. Change detection based on deep feature representation and mapping transformation for multi-spatial-resolution remote sensing images

    NASA Astrophysics Data System (ADS)

    Zhang, Puzhao; Gong, Maoguo; Su, Linzhi; Liu, Jia; Li, Zhizhou

    2016-06-01

    Multi-spatial-resolution change detection is a newly proposed issue and it is of great significance in remote sensing, environmental and land use monitoring, etc. Though multi-spatial-resolution image-pair are two kinds of representations of the same reality, they are often incommensurable superficially due to their different modalities and properties. In this paper, we present a novel multi-spatial-resolution change detection framework, which incorporates deep-architecture-based unsupervised feature learning and mapping-based feature change analysis. Firstly, we transform multi-resolution image-pair into the same pixel-resolution through co-registration, followed by details recovery, which is designed to remedy the spatial details lost in the registration. Secondly, the denoising autoencoder is stacked to learn local and high-level representation/feature from the local neighborhood of the given pixel, in an unsupervised fashion. Thirdly, motivated by the fact that multi-resolution image-pair share the same reality in the unchanged regions, we try to explore the inner relationships between them by building a mapping neural network. And it can be used to learn a mapping function based on the most-unlikely-changed feature-pairs, which are selected from all the feature-pairs via a coarse initial change map generated in advance. The learned mapping function can bridge the different representations and highlight changes. Finally, we can build a robust and contractive change map through feature similarity analysis, and the change detection result is obtained through the segmentation of the final change map. Experiments are carried out on four real datasets, and the results confirmed the effectiveness and superiority of the proposed method.

  11. Radiometric Calibration Assessment of Commercial High Spatial Resolution Multispectral Image Products

    NASA Technical Reports Server (NTRS)

    Thome, Kurt; Leisso, Nathan; Buchanan, John

    2007-01-01

    This paper describes the results of commercial high spatial resolution sensors. The topics include: 1) Reflectance-based approach; 2) U of A test sites; 3) Test Site Selection; 4) Resort Living; 5) Aerosol parameters; 6) Surface reflectance retrieval; 7) Accuracy/precision; 8) Data sets; 9) June 23, 2005 for Ikonos; 10) QuickBird Results; 11) Ikonos results; 12) Orbview results; 13) Ikonos redux; and 14) Overall results.

  12. High spatial and temporal resolution imaging of the arterial vasculature of the lower extremity with contrast enhanced MR angiography.

    PubMed

    Mostardi, Petrice M; Haider, Clifton R; Glockner, James F; Young, Phillip M; Riederer, Stephen J

    2011-05-01

    Vascular imaging can be essential in the diagnosis, monitoring, and planning and assessment of treatment of patients with peripheral vascular disease. The purpose of this work is to describe a recently developed three-dimensional (3D) time-resolved contrast-enhanced MR angiography (CE-MRA) technique, Cartesian Acquisition with Projection Reconstruction-like sampling (CAPR), and its application to imaging of the vasculature of the lower legs and feet. CAPR implements accelerated imaging techniques and uses specialized multielement imaging coil arrays to achieve high temporal and high spatial resolution imaging. Volunteer and patient studies of the vasculature of the lower legs and feet have been performed. Temporal resolution of 4.9-6.5 sec and spatial resolution less than or equal to 1 mm in all directions allow for the depiction of progressive arterial filling and complex flow patterns as well as sharp visualization of vascular structure as small as the fine muscular branches. High-quality diagnostic imaging is made possible with CAPR's advanced acquisition and reconstruction techniques and the use of specialized coil arrays. PMID:21509813

  13. High Spatial and Temporal Resolution Imaging of the Arterial Vasculature of the Lower Extremity With Contrast Enhanced MR Angiography

    PubMed Central

    MOSTARDI, PETRICE M.; HAIDER, CLIFTON R.; GLOCKNER, JAMES F.; YOUNG, PHILLIP M.; RIEDERER, STEPHEN J.

    2011-01-01

    Vascular imaging can be essential in the diagnosis, monitoring, and planning and assessment of treatment of patients with peripheral vascular disease. The purpose of this work is to describe a recently developed three-dimensional (3D) time-resolved contrast-enhanced MR angiography (CE-MRA) technique, Cartesian Acquisition with Projection Reconstruction-like sampling (CAPR), and its application to imaging of the vasculature of the lower legs and feet. CAPR implements accelerated imaging techniques and uses specialized multielement imaging coil arrays to achieve high temporal and high spatial resolution imaging. Volunteer and patient studies of the vasculature of the lower legs and feet have been performed. Temporal resolution of 4.9–6.5 sec and spatial resolution less than or equal to 1 mm in all directions allow for the depiction of progressive arterial filling and complex flow patterns as well as sharp visualization of vascular structure as small as the fine muscular branches. High-quality diagnostic imaging is made possible with CAPR’s advanced acquisition and reconstruction techniques and the use of specialized coil arrays. PMID:21509813

  14. Classification of high spatial resolution images by means of a Gabor wavelet decomposition and a support vector machine

    NASA Astrophysics Data System (ADS)

    Baraldi, Andrea; Bruzzone, Lorenzo

    2004-11-01

    Very high spatial resolution satellite images, acquired by third-generation commercial remote sensing (RS) satellites (like Ikonos and QuickBird), are characterized by a tremendous spatial complexity, i.e. surface objects are described by a combination of spectral, textural and shape information. Potentially capable of dealing with the spatial complexity of such images, context-sensitive data mapping systems, e.g. employing filter sets designed for texture feature analysis/synthesis, have been extensively studied in pattern recognition literature in recent years. In this work, four implementations of a two-stage classification scheme for the analysis of high spatial resolution images are compared. Competing first stage (feature extraction) implementations of increasing complexity are: 1) a standard multi-scale dyadic Gaussian pyramid image decomposition, and 2) an original almost complete (near-orthogonal) basis for the Gabor wavelet transform of an input image at selected spatial frequencies (i.e. band-pass filter central frequency and filter orientation pairs). The second stage of the classification scheme consists of: a) an ensemble of pixel-based two-class support vector machines (SVMs) applied to the multi-class classification problem according to the one-against-one strategy, exploiting the well-known SVM's capability of dealing with high dimensional mapping problems; and b) a traditional two-phase supervised learning pixel-based Radial Basis Function (RBF) network. In a badly-posed Ikonos image classification experiment, SVM combined with the two filter sets provide an interesting compromise between ease of use (i.e. easy free parameter selection), classification accuracy, robustness to changes in surface properties, capability of detecting genuine, but small, image details as well as linear structures. Qualitatively and quantitatively, the multi-scale multi-orientation almost complete Gabor wavelet transform appears superior to the dyadic multi

  15. Prospective comparison of high- and low-spatial-resolution dynamic MR imaging with sensitivity encoding (SENSE) for hypervascular hepatocellular carcinoma.

    PubMed

    Tsurusaki, Masakatsu; Semelka, Richard C; Uotani, Kensuke; Sugimoto, Koji; Fujii, Masahiko; Sugimura, Kazuro

    2008-10-01

    The purpose of this study was to prospectively evaluate the efficacy of high-spatial-resolution dynamic MRI using sensitivity encoding (SENSE) in detection of hypervascular hepatocellular carcinoma (HCC). Thirty-five patients were included in this prospectively planned study, and 25 patients with 31 HCCs were assigned into three groups and underwent the following sequences: group A (n=11): three-dimensional fast-gradient-echo (3D-FGE) high-spatial-resolution dynamic MRI (HR-MRI) with SENSE; group B (n=10): 3D-FGE low-spatial-resolution dynamic MRI (LR-MRI) with SENSE; and group C (n=14): 3D-FGE/LR-MRI without SENSE. For the quantitative analysis, the lesion-to-liver contrast-to-noise ratio (CNR) between the liver and HCCs was measured. For the qualitative analysis, overall image quality for each group was evaluated with a five-point scale analysis. The sensitivities for detection of HCCs were evaluated. The overall image quality in group A was significantly greater than both groups B and C (P<0.01). The sensitivity of lesion detection on HAP was not significantly higher in group A (100%) than group C (69.2%; P>0.05). In our pilot study on a small number of patients, image quality in HR-MRI with SENSE was superior to LR-MRI. A high detection rate was seen with HR-MRI with SENSE in the patients with hypervascular HCCs. PMID:18446347

  16. Object Based Image Analysis Combining High Spatial Resolution Imagery and Laser Point Clouds for Urban Land Cover

    NASA Astrophysics Data System (ADS)

    Zou, Xiaoliang; Zhao, Guihua; Li, Jonathan; Yang, Yuanxi; Fang, Yong

    2016-06-01

    With the rapid developments of the sensor technology, high spatial resolution imagery and airborne Lidar point clouds can be captured nowadays, which make classification, extraction, evaluation and analysis of a broad range of object features available. High resolution imagery, Lidar dataset and parcel map can be widely used for classification as information carriers. Therefore, refinement of objects classification is made possible for the urban land cover. The paper presents an approach to object based image analysis (OBIA) combing high spatial resolution imagery and airborne Lidar point clouds. The advanced workflow for urban land cover is designed with four components. Firstly, colour-infrared TrueOrtho photo and laser point clouds were pre-processed to derive the parcel map of water bodies and nDSM respectively. Secondly, image objects are created via multi-resolution image segmentation integrating scale parameter, the colour and shape properties with compactness criterion. Image can be subdivided into separate object regions. Thirdly, image objects classification is performed on the basis of segmentation and a rule set of knowledge decision tree. These objects imagery are classified into six classes such as water bodies, low vegetation/grass, tree, low building, high building and road. Finally, in order to assess the validity of the classification results for six classes, accuracy assessment is performed through comparing randomly distributed reference points of TrueOrtho imagery with the classification results, forming the confusion matrix and calculating overall accuracy and Kappa coefficient. The study area focuses on test site Vaihingen/Enz and a patch of test datasets comes from the benchmark of ISPRS WG III/4 test project. The classification results show higher overall accuracy for most types of urban land cover. Overall accuracy is 89.5% and Kappa coefficient equals to 0.865. The OBIA approach provides an effective and convenient way to combine high

  17. A novel coded excitation scheme to improve spatial and contrast resolution of quantitative ultrasound imaging.

    PubMed

    Sanchez, Jose R; Pocci, Darren; Oelze, Michael L

    2009-10-01

    Quantitative ultrasound (QUS) imaging techniques based on ultrasonic backscatter have been used successfully to diagnose and monitor disease. A method for improving the contrast and axial resolution of QUS parametric images by using the resolution enhancement compression (REC) technique is proposed. Resolution enhancement compression is a coded excitation and pulse compression technique that enhances the -6-dB bandwidth of an ultrasonic imaging system. The objective of this study was to combine REC with QUS (REC-QUS) and evaluate and compare improvements in scatterer diameter estimates obtained using the REC technique to conventional pulsing methods. Simulations and experimental measurements were conducted with a single-element transducer (f/4) having a center frequency of 10 MHz and a -6-dB bandwidth of 80%. Using REC, the -6-dB bandwidth was enhanced to 155%. Images for both simulation and experimental measurements contained a signal-to-noise ratio of 28 dB. In simulations, to monitor the improvements in contrast a software phantom with a cylindrical lesion was evaluated. In experimental measurements, tissue-mimicking phantoms that contained glass spheres with different scatterer diameters were evaluated. Estimates of average scatterer diameter in the simulations and experiments were obtained by comparing the normalized backscattered power spectra to theory over the -6-dB bandwidth for both conventional pulsing and REC. Improvements in REC-QUS over conventional QUS were quantified through estimate bias and standard deviation, contrast-to-noise ratio, and histogram analysis of QUS parametric images. Overall, a 51% increase in contrast and a 60% decrease in the standard deviation of average scatterer diameter estimates were obtained during simulations, while a reduction of 34% to 71% was obtained in the standard deviation of average scatterer diameter for the experimental results. PMID:19942499

  18. High spatial resolution imaging of methane and other trace gases with the airborne Hyperspectral Thermal Emission Spectrometer (HyTES)

    NASA Astrophysics Data System (ADS)

    Hulley, Glynn C.; Duren, Riley M.; Hopkins, Francesca M.; Hook, Simon J.; Vance, Nick; Guillevic, Pierre; Johnson, William R.; Eng, Bjorn T.; Mihaly, Jonathan M.; Jovanovic, Veljko M.; Chazanoff, Seth L.; Staniszewski, Zak K.; Kuai, Le; Worden, John; Frankenberg, Christian; Rivera, Gerardo; Aubrey, Andrew D.; Miller, Charles E.; Malakar, Nabin K.; Sánchez Tomás, Juan M.; Holmes, Kendall T.

    2016-06-01

    Currently large uncertainties exist associated with the attribution and quantification of fugitive emissions of criteria pollutants and greenhouse gases such as methane across large regions and key economic sectors. In this study, data from the airborne Hyperspectral Thermal Emission Spectrometer (HyTES) have been used to develop robust and reliable techniques for the detection and wide-area mapping of emission plumes of methane and other atmospheric trace gas species over challenging and diverse environmental conditions with high spatial resolution that permits direct attribution to sources. HyTES is a pushbroom imaging spectrometer with high spectral resolution (256 bands from 7.5 to 12 µm), wide swath (1-2 km), and high spatial resolution (˜ 2 m at 1 km altitude) that incorporates new thermal infrared (TIR) remote sensing technologies. In this study we introduce a hybrid clutter matched filter (CMF) and plume dilation algorithm applied to HyTES observations to efficiently detect and characterize the spatial structures of individual plumes of CH4, H2S, NH3, NO2, and SO2 emitters. The sensitivity and field of regard of HyTES allows rapid and frequent airborne surveys of large areas including facilities not readily accessible from the surface. The HyTES CMF algorithm produces plume intensity images of methane and other gases from strong emission sources. The combination of high spatial resolution and multi-species imaging capability provides source attribution in complex environments. The CMF-based detection of strong emission sources over large areas is a fast and powerful tool needed to focus on more computationally intensive retrieval algorithms to quantify emissions with error estimates, and is useful for expediting mitigation efforts and addressing critical science questions.

  19. High spatial resolution fast-neutron imaging detectors for Pulsed Fast-Neutron Transmission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mor, I.; Vartsky, D.; Bar, D.; Feldman, G.; Goldberg, M. B.; Katz, D.; Sayag, E.; Shmueli, I.; Cohen, Y.; Tal, A.; Vagish, Z.; Bromberger, B.; Dangendorf, V.; Mugai, D.; Tittelmeier, K.; Weierganz, M.

    2009-05-01

    Two generations of a novel detector for high-resolution transmission imaging and spectrometry of fast-neutrons are presented. These devices are based on a hydrogenous fiber scintillator screen and single- or multiple-gated intensified camera systems (ICCD). This detector is designed for energy-selective neutron radiography with nanosecond-pulsed broad-energy (1-10 MeV) neutron beams. Utilizing the Time-of-Flight (TOF) method, such a detector is capable of simultaneously capturing several images, each at a different neutron energy (TOF). In addition, a gamma-ray image can also be simultaneously registered, allowing combined neutron/gamma inspection of objects. This permits combining the sensitivity of the fast-neutron resonance method to low-Z elements with that of gamma radiography to high-Z materials.

  20. X-ray optical system for imaging laser plumes with a spatial resolution of up to 70 nm

    NASA Astrophysics Data System (ADS)

    Nechai, A. N.; Pestov, A. E.; Polkovnikov, V. N.; Salashchenko, N. N.; Toropov, M. N.; Chkhalo, N. I.; Tsybin, N. N.; Shcherbakov, A. V.

    2016-04-01

    We consider an X-ray optical system which permits obtaining laser plume images at a wavelength of 13.5 nm with a resolution of up to 70 nm. The X-ray optical system comprises an X-ray Schwarzschild objective made up of two aspherical multilayer mirrors, a scintillator (YAG : Ce ceramics), which converts X-rays to the visible radiation, and a visible-optical system, which images the scintillator surface onto a CCD camera. The spatial resolution of the system is limited by the resolution of the optical system (0.7 μm) and the magnification (10×) of the X-ray objective and is as high as 70 nm. The effect of Schwarzschild objective mirror shapes on the spatial resolution is analysed. The profile of concave mirror aspherisation is considered, which provides the attainment of the diffraction-limited quality of the objective. Data are given for the quantum efficiency of the system at a wavelength of 13.5 nm. We describe the experimental test bench intended for studying the developed X-ray optical system and outline the first experimental data which illustrate its efficiency. Owing to the natural division into the 'X-ray' and 'visible' parts, the optical system under discussion permits an easy change of the magnification and the field of view without realigning the X-ray optical elements. The wavelength may be varied in a range between 3 and 40 nm by changing the multilayer mirrors.

  1. X-ray phase-contrast tomography for high-spatial-resolution zebrafish muscle imaging

    PubMed Central

    Vågberg, William; Larsson, Daniel H.; Li, Mei; Arner, Anders; Hertz, Hans M.

    2015-01-01

    Imaging of muscular structure with cellular or subcellular detail in whole-body animal models is of key importance for understanding muscular disease and assessing interventions. Classical histological methods for high-resolution imaging methods require excision, fixation and staining. Here we show that the three-dimensional muscular structure of unstained whole zebrafish can be imaged with sub-5 μm detail with X-ray phase-contrast tomography. Our method relies on a laboratory propagation-based phase-contrast system tailored for detection of low-contrast 4–6 μm subcellular myofibrils. The method is demonstrated on 20 days post fertilization zebrafish larvae and comparative histology confirms that we resolve individual myofibrils in the whole-body animal. X-ray imaging of healthy zebrafish show the expected structured muscle pattern while specimen with a dystrophin deficiency (sapje) displays an unstructured pattern, typical of Duchenne muscular dystrophy. The method opens up for whole-body imaging with sub-cellular detail also of other types of soft tissue and in different animal models. PMID:26564785

  2. X-ray phase-contrast tomography for high-spatial-resolution zebrafish muscle imaging

    NASA Astrophysics Data System (ADS)

    Vågberg, William; Larsson, Daniel H.; Li, Mei; Arner, Anders; Hertz, Hans M.

    2015-11-01

    Imaging of muscular structure with cellular or subcellular detail in whole-body animal models is of key importance for understanding muscular disease and assessing interventions. Classical histological methods for high-resolution imaging methods require excision, fixation and staining. Here we show that the three-dimensional muscular structure of unstained whole zebrafish can be imaged with sub-5 μm detail with X-ray phase-contrast tomography. Our method relies on a laboratory propagation-based phase-contrast system tailored for detection of low-contrast 4-6 μm subcellular myofibrils. The method is demonstrated on 20 days post fertilization zebrafish larvae and comparative histology confirms that we resolve individual myofibrils in the whole-body animal. X-ray imaging of healthy zebrafish show the expected structured muscle pattern while specimen with a dystrophin deficiency (sapje) displays an unstructured pattern, typical of Duchenne muscular dystrophy. The method opens up for whole-body imaging with sub-cellular detail also of other types of soft tissue and in different animal models.

  3. WE-G-17A-01: Improving Tracking Image Spatial Resolution for Onboard MR Image Guided Radiation Therapy Using the WHISKEE Technique

    SciTech Connect

    Hu, Y; Mutic, S; Du, D; Green, O; Zeng, Q; Nana, R; Patrick, J; Shvartsman, S; Dempsey, J

    2014-06-15

    Purpose: To evaluate the feasibility of using the weighted hybrid iterative spiral k-space encoded estimation (WHISKEE) technique to improve spatial resolution of tracking images for onboard MR image guided radiation therapy (MR-IGRT). Methods: MR tracking images of abdomen and pelvis had been acquired from healthy volunteers using the ViewRay onboard MRIGRT system (ViewRay Inc. Oakwood Village, OH) at a spatial resolution of 2.0mm*2.0mm*5.0mm. The tracking MR images were acquired using the TrueFISP sequence. The temporal resolution had to be traded off to 2 frames per second (FPS) to achieve the 2.0mm in-plane spatial resolution. All MR images were imported into the MATLAB software. K-space data were synthesized through the Fourier Transform of the MR images. A mask was created to selected k-space points that corresponded to the under-sampled spiral k-space trajectory with an acceleration (or undersampling) factor of 3. The mask was applied to the fully sampled k-space data to synthesize the undersampled k-space data. The WHISKEE method was applied to the synthesized undersampled k-space data to reconstructed tracking MR images at 6 FPS. As a comparison, the undersampled k-space data were also reconstructed using the zero-padding technique. The reconstructed images were compared to the original image. The relatively reconstruction error was evaluated using the percentage of the norm of the differential image over the norm of the original image. Results: Compared to the zero-padding technique, the WHISKEE method was able to reconstruct MR images with better image quality. It significantly reduced the relative reconstruction error from 39.5% to 3.1% for the pelvis image and from 41.5% to 4.6% for the abdomen image at an acceleration factor of 3. Conclusion: We demonstrated that it was possible to use the WHISKEE method to expedite MR image acquisition for onboard MR-IGRT systems to achieve good spatial and temporal resolutions simultaneously. Y. Hu and O. green

  4. Simultaneous High-Resolution 2-Dimensional Spatial and 1-Dimensional Picosecond Streaked X-ray Pinhole Imaging

    SciTech Connect

    Steel, A B; Nagel, S R; Dunn, J; Baldis, H A

    2012-05-03

    A Kentech x-ray streak camera was run at the LLNL Compact Multipulse Terawatt (COMET) laser to record simultaneous space- and time-resolved measurements of picosecond laser-produced plasmas. Four different x-ray energy channels were monitored using broad-band filters to record the time history of Cu targets heated at irradiances of 10{sup 16} - 10{sup 19} W/cm{sup 2}. Through the Cu filter channel, a time-resolution below 3ps was obtained. Additionally, an array of 10 {micro}m diameter pinholes was placed in front of the camera to produce multiple time-resolved x-ray images on the photocathode and time-integrated images on the phosphor with 10 and 15 times magnification, respectively, with spatial resolution of <13 {micro}m.

  5. High-Spatial-Resolution Imaging Combining High-Order Adaptive Optics, Frame Selection, and Speckle Masking Reconstruction

    NASA Astrophysics Data System (ADS)

    Denker, Carsten; Mascarinas, Dulce; Xu, Yan; Cao, Wenda; Yang, Guo; Wang, Haimin; Goode, Philip R.; Rimmele, Thomas

    2005-04-01

    We present, for the first time, high-spatial-resolution observations combining high-order adaptive optics (AO), frame selection, and post-facto image correction via speckle masking. The data analysis is based on observations of solar active region NOAA 10486 taken with the Dunn Solar Telescope (DST) at the Sacramento Peak Observatory (SPO) of the National Solar Observatory (NSO) on 29 October 2003. The high Strehl ratio encountered in AO corrected short-exposure images provides highly improved signal-to-noise ratios leading to a superior recovery of the object’s Fourier phases. This allows reliable detection of small-scale solar features near the diffraction limit of the telescope. Speckle masking imaging provides access to high-order wavefront aberrations, which predominantly originate at high atmospheric layers and are only partially corrected by the AO system. In addition, the observations provided qualitative measures of the image correction away from the lock point of the AO system. We further present a brief inspection of the underlying imaging theory discussing the limitations and prospects of this multi-faceted image reconstruction approach in terms of the recovery of spatial information, photometric accuracy, and spectroscopic applications.

  6. Reversible cryo-arrest for imaging molecules in living cells at high spatial resolution.

    PubMed

    Masip, Martin E; Huebinger, Jan; Christmann, Jens; Sabet, Ola; Wehner, Frank; Konitsiotis, Antonios; Fuhr, Günther R; Bastiaens, Philippe I H

    2016-08-01

    The dynamics of molecules in living cells hampers precise imaging of molecular patterns by functional and super-resolution microscopy. We developed a method that circumvents lethal chemical fixation and allows on-stage cryo-arrest for consecutive imaging of molecular patterns within the same living, but arrested, cells. The reversibility of consecutive cryo-arrests was demonstrated by the high survival rate of different cell lines and by intact growth factor signaling that was not perturbed by stress response. Reversible cryo-arrest was applied to study the evolution of ligand-induced receptor tyrosine kinase activation at different scales. The nanoscale clustering of epidermal growth factor receptor (EGFR) in the plasma membrane was assessed by single-molecule localization microscopy, and endosomal microscale activity patterns of ephrin receptor A2 (EphA2) were assessed by fluorescence lifetime imaging microscopy. Reversible cryo-arrest allows the precise determination of molecular patterns while conserving the dynamic capabilities of living cells. PMID:27400419

  7. Investigating the effect of pixel size of high spatial resolution FTIR imaging for detection of colorectal cancer

    NASA Astrophysics Data System (ADS)

    Lloyd, G. R.; Nallala, J.; Stone, N.

    2016-03-01

    FTIR is a well-established technique and there is significant interest in applying this technique to medical diagnostics e.g. to detect cancer. The introduction of focal plane array (FPA) detectors means that FTIR is particularly suited to rapid imaging of biopsy sections as an adjunct to digital pathology. Until recently however each pixel in the image has been limited to a minimum of 5.5 µm which results in a comparatively low magnification image or histology applications and potentially the loss of important diagnostic information. The recent introduction of higher magnification optics gives image pixels that cover approx. 1.1 µm. This reduction in image pixel size gives images of higher magnification and improved spatial detail can be observed. However, the effect of increasing the magnification on spectral quality and the ability to discriminate between disease states is not well studied. In this work we test the discriminatory performance of FTIR imaging using both standard (5.5 µm) and high (1.1 µm) magnification for the detection of colorectal cancer and explore the effect of binning to degrade high resolution images to determine whether similar diagnostic information and performance can be obtained using both magnifications. Results indicate that diagnostic performance using high magnification may be reduced as compared to standard magnification when using existing multivariate approaches. Reduction of the high magnification data to standard magnification via binning can potentially recover some of the lost performance.

  8. Spatial resolution enhancement of hyperspectral image based on the combination of spectral mixing model and observation model

    NASA Astrophysics Data System (ADS)

    Zhang, Yifan

    2014-10-01

    To improve the spatial resolution of a hyperspectral (HS) observation of a scene with the aid of an auxiliary multispectral (MS) observation, a new spectral unmixing-based HS and MS image fusion approach is presented in this paper. In the proposed fusion approach, linear spectral unmixing with sparsity constraint is employed, by taking the impact of linear observation model on linear mixing model into consideration. Simulative experiment is employed for verification and comparison. It is illustrated that the proposed approach would be more promising for practical utilization compared to some state-of-the-art approaches, due to its good balance between fusion performance and calculation cost.

  9. Comparison of spatial resolution between tomographic images and ghosts in rotational panoramic radiography: the effect of the first slit width.

    PubMed

    Wakoh, M; Yamamoto, K; Fujimori, H; Kuroyanagi, K

    1992-11-01

    Rotational panoramic radiography projects the object placed within the focal trough as tomographic images with minimal distortion. However, even if an object is within the focal trough, the sharpness of the image is affected by the position of the object, the difference in the relative speed of the X-ray source against the film and the difference in the direction of rotation. In this study, spatial resolutions of ghosts and tomographic images were compared. Ghosts, as well as tomographic images, were obtained from the object placed in the focal trough. The effects of the width of the first slit, a major parameter affecting image quality, were the primary concern in this study. With regard to ghosts, the influence of the position of object, in terms of central, buccal and lingual regions the focal trough, was also analyzed. The target of analysis was the mandibular ramus region. An Orthopantomograph OP5, a conventional panoramic apparatus, was used. An X-ray test chart, X-ray beams, and H-D curve were prepared for calculation of the Modulation Transfer Function (MTF), and the slit method using the Fourier transforms was applied. When the width of the first slit was changed displacement of MTF curves was most remarkable for the superimposed tomographic image which was scanned 10 mm posterior to the X-axis connecting the right and left lateral rotation centers. For reduction of the spatial resolution of ghosts, it was found effective to use a wider slit and place the object at a position lingual to the central plane. PMID:1303325

  10. Redox and speciation mapping of rock thin sections using high spatial resolution full-field imaging technique

    NASA Astrophysics Data System (ADS)

    de Andrade, V.; Susini, J.; Salomé, M.; Beraldin, O.; Heymes, T.; Lewin, E.

    2009-04-01

    Because of their complex genesis, natural rocks are the most often heterogeneous systems, with various scale-level heterogeneities for both chemistry and structure. In the last decade, the dramatic improvements of hyperspectral imaging techniques provided new tools for accurate material characterisation. Most of these micro- and nano- analytical techniques rely on scanning instruments, which offer high spatial resolution but suffer from long acquisition times imposing practical limits on the field of view. Conversely, full-field imaging techniques rely on a fast parallel acquisition but have limited resolution. Although soft X-ray full-field microscopes based on Fresnel zone plates are commonly used for high resolution imaging, its combination with spectroscopy is challenging and 2D chemical mapping still difficult. For harder X-rays, lensless X-ray microscope based on simple propagation geometry is easier and can be readily used for 2D spectro-microscopy. A full-field experimental setup was optimized at the ESRF-ID21 beamline to image iron redox and speciation distributions in rocks thin sections. The setup comprises a Si111 or Si220 (E = 0.4 eV) monochromator, a special sample stage and a sensitive camera associated with a brand new GGG:Eu light conversion scintillator and high magnification visible light optics. The pixel size ranges from 1.6 to 0.16 m according to the optic used. This instrument was used to analyse phyllosilicates and oxides of metamorphic sediments coming from the Aspromonte nappes-pile in Calabria. Iron chemical state distributions were derived - from images of 1000 Ã- 2000 Ã- 30 m3 rock thin sections - by subtraction of absorption images above and below the Fe K-edge. Using an automatic stitching reconstruction, a wide field image (4Ã-3 mm2 with a 1 m2 resolution for a total of about 12 millions pixels) of Fetotal elemental distribution was produced. Moreover, -XANES analyses (more than 1 million individual -XANES spectra) were performed

  11. Space station image captures a red tide ciliate bloom at high spectral and spatial resolution

    PubMed Central

    Dierssen, Heidi; McManus, George B.; Chlus, Adam; Qiu, Dajun; Gao, Bo-Cai; Lin, Senjie

    2015-01-01

    Mesodinium rubrum is a globally distributed nontoxic ciliate that is known to produce intense red-colored blooms using enslaved chloroplasts from its algal prey. Although frequent enough to have been observed by Darwin, blooms of M. rubrum are notoriously difficult to quantify because M. rubrum can aggregate into massive clouds of rusty-red water in a very short time due to its high growth rates and rapid swimming behavior and can disaggregate just as quickly by vertical or horizontal dispersion. A September 2012 hyperspectral image from the Hyperspectral Imager for the Coastal Ocean sensor aboard the International Space Station captured a dense red tide of M. rubrum (106 cells per liter) in surface waters of western Long Island Sound. Genetic data confirmed the identity of the chloroplast as a cryptophyte that was actively photosynthesizing. Microscopy indicated extremely high abundance of its yellow fluorescing signature pigment phycoerythrin. Spectral absorption and fluorescence features were related to ancillary photosynthetic pigments unique to this organism that cannot be observed with traditional satellites. Cell abundance was estimated at a resolution of 100 m using an algorithm based on the distinctive yellow fluorescence of phycoerythrin. Future development of hyperspectral satellites will allow for better enumeration of bloom-forming coastal plankton, the associated physical mechanisms, and contributions to marine productivity. PMID:26627232

  12. Space station image captures a red tide ciliate bloom at high spectral and spatial resolution.

    PubMed

    Dierssen, Heidi; McManus, George B; Chlus, Adam; Qiu, Dajun; Gao, Bo-Cai; Lin, Senjie

    2015-12-01

    Mesodinium rubrum is a globally distributed nontoxic ciliate that is known to produce intense red-colored blooms using enslaved chloroplasts from its algal prey. Although frequent enough to have been observed by Darwin, blooms of M. rubrum are notoriously difficult to quantify because M. rubrum can aggregate into massive clouds of rusty-red water in a very short time due to its high growth rates and rapid swimming behavior and can disaggregate just as quickly by vertical or horizontal dispersion. A September 2012 hyperspectral image from the Hyperspectral Imager for the Coastal Ocean sensor aboard the International Space Station captured a dense red tide of M. rubrum (10(6) cells per liter) in surface waters of western Long Island Sound. Genetic data confirmed the identity of the chloroplast as a cryptophyte that was actively photosynthesizing. Microscopy indicated extremely high abundance of its yellow fluorescing signature pigment phycoerythrin. Spectral absorption and fluorescence features were related to ancillary photosynthetic pigments unique to this organism that cannot be observed with traditional satellites. Cell abundance was estimated at a resolution of 100 m using an algorithm based on the distinctive yellow fluorescence of phycoerythrin. Future development of hyperspectral satellites will allow for better enumeration of bloom-forming coastal plankton, the associated physical mechanisms, and contributions to marine productivity. PMID:26627232

  13. Energy-selective neutron imaging with high spatial resolution and its impact on the study of crystalline-structured materials

    NASA Astrophysics Data System (ADS)

    Lehmann, E. H.; Peetermans, S.; Josic, L.; Leber, H.; van Swygenhoven, H.

    2014-01-01

    Crystalline-structured materials with preferentially large grains were investigated by means of energy-selective neutron imaging methods (transmission radiography and tomography) under the conditions of the best possible spatial resolution at the ICON facility, SINQ, and PSI. Because of the cold spectrum at that beam line, access to the Bragg diffraction features was possible even when the energy resolution of the used selector device was only 15%. Grains with a size below the detector resolution (approximately 25 μm) are not visible, and a quasi-homogeneous contrast variation is found when the neutron energy is varied.In the cases of welded stainless steel samples and rolled Al plates, we obtained structural information from a very short exposure of approximately 60 s. Tomographic examinations of these samples at suitable neutron energies qualitatively verified the radiographic findings by showing the same features in the bulk. Comparison to common electron backscatter diffraction (EBSD) investigations in selected regions of the samples provided a complete verification of the neutron-image data with respect to the grain size and the different grain orientations. The method of energy-selective neutron imaging provides an easy and straightforward approach for non-invasive material research that can be performed without any sample preparation if the most suitable neutron energy is chosen. Further studies will be necessary to extend the experimental data base to other materials with different crystal structures and grain sizes. A comparison to diffraction data will enhance the quantitative value of the investigations.

  14. Dynamics of femtosecond laser-induced periodic surface structures on silicon by high spatial and temporal resolution imaging

    SciTech Connect

    Jia, X.; Jia, T. Q. Peng, N. N.; Feng, D. H.; Zhang, S. A.; Sun, Z. R.

    2014-04-14

    The formation dynamics of periodic ripples induced by femtosecond laser pulses (pulse duration τ = 50 fs and central wavelength λ = 800 nm) are studied by a collinear pump-probe imaging technique with a temporal resolution of 1 ps and a spatial resolution of 440 nm. The ripples with periods close to the laser wavelength begin to appear upon irradiation of two pump pulses at surface defects produced by the prior one. The rudiments of periodic ripples emerge in the initial tens of picoseconds after fs laser irradiation, and the ripple positions keep unmoved until the formation processes complete mainly in a temporal span of 1500 ps. The results suggest that the periodic deposition of laser energy during the interaction between femtosecond laser pulses and sample surface plays a dominant role in the formation of periodic ripples.

  15. Exploring Small Spatial Scales in the Transition Region and Solar Corona with the Very High Angular Resolution Imaging Spectrometer (VERIS)

    NASA Astrophysics Data System (ADS)

    Chua, D. H.; Korendyke, C. M.; Vourlidas, A.; Brown, C. M.; Tun-Beltran, S.; Klimchuk, J. A.; Landi, E.; Seely, J.; Davila, J. M.; Hagood, R.; Roberts, D.; Shepler, E.; Feldman, R.; Moser, J.; Shea, J.

    2012-12-01

    Theoretical and experimental investigations of the transition region and coronal loops point to the importance of processes occurring on small spatial scales in governing the strong dynamics and impulsive energy release in these regions. As a consequence, high spatial, temporal, and temperature resolution over a broad temperature range, and accuracy in velocity and density determinations are all critical observational parameters. Current instruments lack one or more of these properties. These observational deficiencies have created a wide array of opposing descriptions of coronal loop heating and questions such as whether or not the plasma within coronal loops is multi-thermal or isothermal. High spectral and spatial resolution spectroscopic data are absolutely required to resolve these controversies and to advance our understanding of the dynamics within the solar atmosphere. We will achieve this with the Very High Angular Resolution Imaging Spectrometer (VERIS) sounding rocket payload. VERIS consists of an off-axis paraboloid telescope feeding a very high angular resolution, extreme ultraviolet (EUV) imaging spectrometer that will provide the first ever, simultaneous sub-arcsecond (0.16 arcsecond/pixel) spectra in bright lines needed to study plasma structures in the transition region, quiet corona, and active region core. It will do so with a spectral resolution of >5000 to allow Doppler velocity determinations to better than 3 km/s. VERIS uses a novel two-element, normal incidence optical design with highly reflective, broad wavelength coverage EUV coatings to access a spectral range with broad temperature coverage (0.03-15 MK) and density-sensitive line ratios. Combined with Hinode Solar Optical Telescope (SOT) and ground based observatories, VERIS will deliver simultaneous observations of the entire solar atmosphere from the photosphere to the multi-million degree corona at sub-arcsecond resolution for the first time ever, allowing us to understand the

  16. Evaluation of ERTS-1 image sensor spatial resolution in photographic form

    NASA Technical Reports Server (NTRS)

    Slater, P. N. (Principal Investigator); Schowengerdt, R. A.

    1975-01-01

    The author has identified the following significant results. The digital Optical Transfer Function (OTF) measurements showed the following: (1) there are no significant differences in optical performance, in terms of OTF, among all four bands of the multispectral scanner, (2) no substantial changes in the OTF's of bands 4, 5, and 6 during the period November 1972 to May 1973, and (3) comparison between the photographic and digital (CCT) two-dimensional OTF's indicated a strong asymmetry in the photographic product OTF between the MSS scan direction and across scan direction. The coherent light Fourier analysis program showed the following: (1) for agricultural areas, bands 5 and 7 of the MSS are superior in terms of image definition, and therefore mapping and acreage estimation, (2) amplitude modulation in imagery from MSS bands 4 and 5 is between 65 to 90 percent of that in corresponding bands of Apollo 9 imagery (SO65), and (3) MSS band 5 imagery has a ground resolution between 55 to 75 percent of that exhibited in the corresponding band of Apollo 9 imagery (SO65).

  17. High-Spatial and High-Mass Resolution Imaging of Surface Metabolites of Arabidopsis thaliana by Laser Desorption-Ionization Mass Spectrometry Using Colloidal Silver

    SciTech Connect

    Jun, Ji Hyun; Song, Zhihong; Liu, Zhenjiu; Nikolau, Basil J.; Yeung, Edward S.; and Lee, Young Jin

    2010-03-17

    High-spatial resolution and high-mass resolution techniques are developed and adopted for the mass spectrometric imaging of epicuticular lipids on the surface of Arabidopsis thaliana. Single cell level spatial resolution of {approx}12 {micro}m was achieved by reducing the laser beam size by using an optical fiber with 25 {micro}m core diameter in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer and improved matrix application using an oscillating capillary nebulizer. Fine chemical images of a whole flower were visualized in this high spatial resolution showing substructure of an anther and single pollen grains at the stigma and anthers. The LTQ-Orbitrap with a MALDI ion source was adopted to achieve MS imaging in high mass resolution. Specifically, isobaric silver ion adducts of C29 alkane (m/z 515.3741) and C28 aldehyde (m/z 515.3377), indistinguishable in low-resolution LTQ, can now be clearly distinguished and their chemical images could be separately constructed. In the application to roots, the high spatial resolution allowed molecular MS imaging of secondary roots and the high mass resolution allowed direct identification of lipid metabolites on root surfaces.

  18. The x-ray light valve: a low-cost, digital radiographic imaging system--spatial resolution.

    PubMed

    MacDougall, Robert D; Koprinarov, Ivaylo; Rowlands, J A

    2008-09-01

    An x-ray light valve (XLV) coupled with an optical scanner has the potential to meet the need for a low-cost, high quality digital imaging system for general radiography. The XLV/scanner concept combines three well-established, and hence, low-cost technologies: An amorphous selenium (a-Se) layer as an x-ray-to-charge transducer, a liquid crystal (LC) cell as an analog display, and an optical scanner for image digitization. The XLV consists of an a-Se layer and LC cell in a sandwich structure which produces an optical image in the LC layer upon x-ray exposure. The XLV/scanner system consists of an XLV in combination with an optical scanner for image readout. Here, the effect of each component on the spatial resolution of an XLV/scanner system is investigated. A theoretical model of spatial resolution of an XLV is presented based on calculations of the modulation transfer function (MTF) for a-Se and a LC cell. From these component MTFs, the theoretical MTF of the XLV is derived. The model was validated by experiments on a prototype XLV/scanner system. The MTF of the scanner alone was obtained by scanning an optical test target and the MTF of the XLV/scanner system was measured using x rays. From the measured MTF of the scanner, the theoretical MTF of the XLV/scanner system was established and compared with the experimental results. Good general agreement exists between experimental and theoretical results in the frequency range of interest for general radiography, although the theoretical curves slightly overstate the measured MTFs. The experimental MTF of the XLV was compared with the MTF of two clinical systems and was shown to have the capability to exceed the resolution of flat-panel detectors. From this, the authors can conclude that the XLV has an adequate resolution for general radiography. The XLV/scanner also has the potential to eliminate aliasing while maintaining a MTF that exceeds that of a flat-panel imager. PMID:18841872

  19. The x-ray light valve: A low-cost, digital radiographic imaging system--Spatial resolution

    SciTech Connect

    MacDougall, Robert D.; Koprinarov, Ivaylo; Rowlands, J. A.

    2008-09-15

    An x-ray light valve (XLV) coupled with an optical scanner has the potential to meet the need for a low-cost, high quality digital imaging system for general radiography. The XLV/scanner concept combines three well-established, and hence, low-cost technologies: An amorphous selenium (a-Se) layer as an x-ray-to-charge transducer, a liquid crystal (LC) cell as an analog display, and an optical scanner for image digitization. The XLV consists of an a-Se layer and LC cell in a sandwich structure which produces an optical image in the LC layer upon x-ray exposure. The XLV/scanner system consists of an XLV in combination with an optical scanner for image readout. Here, the effect of each component on the spatial resolution of an XLV/scanner system is investigated. A theoretical model of spatial resolution of an XLV is presented based on calculations of the modulation transfer function (MTF) for a-Se and a LC cell. From these component MTFs, the theoretical MTF of the XLV is derived. The model was validated by experiments on a prototype XLV/scanner system. The MTF of the scanner alone was obtained by scanning an optical test target and the MTF of the XLV/scanner system was measured using x rays. From the measured MTF of the scanner, the theoretical MTF of the XLV/scanner system was established and compared with the experimental results. Good general agreement exists between experimental and theoretical results in the frequency range of interest for general radiography, although the theoretical curves slightly overstate the measured MTFs. The experimental MTF of the XLV was compared with the MTF of two clinical systems and was shown to have the capability to exceed the resolution of flat-panel detectors. From this, the authors can conclude that the XLV has an adequate resolution for general radiography. The XLV/scanner also has the potential to eliminate aliasing while maintaining a MTF that exceeds that of a flat-panel imager.

  20. The x-ray light valve: A low-cost, digital radiographic imaging system—Spatial resolution

    PubMed Central

    MacDougall, Robert D.; Koprinarov, Ivaylo; Rowlands, J. A.

    2008-01-01

    An x-ray light valve (XLV) coupled with an optical scanner has the potential to meet the need for a low-cost, high quality digital imaging system for general radiography. The XLV∕scanner concept combines three well-established, and hence, low-cost technologies: An amorphous selenium (a-Se) layer as an x-ray-to-charge transducer, a liquid crystal (LC) cell as an analog display, and an optical scanner for image digitization. The XLV consists of an a-Se layer and LC cell in a sandwich structure which produces an optical image in the LC layer upon x-ray exposure. The XLV∕scanner system consists of an XLV in combination with an optical scanner for image readout. Here, the effect of each component on the spatial resolution of an XLV∕scanner system is investigated. A theoretical model of spatial resolution of an XLV is presented based on calculations of the modulation transfer function (MTF) for a-Se and a LC cell. From these component MTFs, the theoretical MTF of the XLV is derived. The model was validated by experiments on a prototype XLV∕scanner system. The MTF of the scanner alone was obtained by scanning an optical test target and the MTF of the XLV∕scanner system was measured using x rays. From the measured MTF of the scanner, the theoretical MTF of the XLV∕scanner system was established and compared with the experimental results. Good general agreement exists between experimental and theoretical results in the frequency range of interest for general radiography, although the theoretical curves slightly overstate the measured MTFs. The experimental MTF of the XLV was compared with the MTF of two clinical systems and was shown to have the capability to exceed the resolution of flat-panel detectors. From this, the authors can conclude that the XLV has an adequate resolution for general radiography. The XLV∕scanner also has the potential to eliminate aliasing while maintaining a MTF that exceeds that of a flat-panel imager. PMID:18841872

  1. High spatial resolution optical imaging of the multiple T Tauri system LkHα 262/LkHα 263

    NASA Astrophysics Data System (ADS)

    Velasco, S.; Rebolo, R.; Oscoz, A.; Mackay, C.; Labadie, L.; Garrido, A. Pérez; Crass, J.; Díaz-Sánchez, A.; Femenía, B.; González-Escalera, V.; King, D. L.; López, R. L.; Puga, M.; Rodríguez-Ramos, L. F.; Zuther, J.

    2016-05-01

    We report high spatial resolution i' band imaging of the multiple T Tauri system LkHα 262/LkHα 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2 m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkHα 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkHα 263 are co-moving, that there is orbital motion in the AB pair, and, remarkably, that LkHα 262-263 is a common proper motion system with less than 1 mas/yr relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M⊙ and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low-mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.

  2. High spatial resolution optical imaging of the multiple T Tauri system Lk Hα 262/Lk Hα 263

    NASA Astrophysics Data System (ADS)

    Velasco, S.; Rebolo, R.; Oscoz, A.; Mackay, C.; Labadie, L.; Pérez Garrido, A.; Crass, J.; Díaz-Sánchez, A.; Femenía, B.; González-Escalera, V.; King, D. L.; López, R. L.; Puga, M.; Rodríguez-Ramos, L. F.; Zuther, J.

    2016-08-01

    We report high spatial resolution i' band imaging of the multiple T Tauri system LkHα 262/LkHα 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2-m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkHα 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkHα 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkHα 263 are comoving, that there is orbital motion in the AB pair, and, remarkably, that LkHα 262-263 is a common proper motion system with less than 1 mas yr-1 relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M⊙ and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.

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

    PubMed

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

    2014-11-01

    Recent emergence of human connectome imaging has led to a high demand on angular and spatial resolutions for diffusion magnetic resonance imaging (MRI). While there have been significant growths in high angular resolution diffusion imaging, the improvement in spatial resolution is still limited due to a number of technical challenges, such as the low signal-to-noise ratio and high motion artifacts. As a result, the benefit of a high spatial resolution in the whole-brain connectome imaging has not been fully evaluated in vivo. In this brief report, the impact of spatial resolution was assessed in a newly acquired whole-brain three-dimensional diffusion tensor imaging data set with an isotropic spatial resolution of 0.85 mm. It was found that the delineation of short cortical association fibers is drastically improved as well as the definition of fiber pathway endings into the gray/white matter boundary-both of which will help construct a more accurate structural map of the human brain connectome. PMID:25264168

  4. Spatial and temporal variability in Moderate Resolution Imaging Spectroradiometer-derived surface albedo over global arid regions

    NASA Astrophysics Data System (ADS)

    Tsvetsinskaya, Elena A.; Schaaf, Crystal B.; Gao, Feng; Strahler, Alan H.; Dickinson, Robert E.

    2006-10-01

    We derive spectral and broadband surface albedo for global arid regions from data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Terra spacecraft, at 1 km spatial resolution for 2001. MODIS data show considerable spatial variability both across various arid regions of the globe (from the bright deserts of northern Africa and the Arabian peninsula to substantially less reflective American and Asian deserts) and within regions (variability related to soil and rock types). For example, over arid northern Africa and the Arabian peninsula, albedo in the visible broadband varies by a factor of over 2, from the brightest sand sheets to the darkest luvisols. Few, if any, global and regional land-atmosphere models capture this observed spatial variability in surface albedo over arid regions. We suggest a scheme that relates soil groups (based on the United Nations Food and Agriculture Organization (FAO) soil classification) to MODIS-derived surface albedo statistics. This approach allows for an efficient representation in climate and weather forecasting models of the observed spatial and temporal variability in surface albedo over global deserts. Observed variability in albedo was reduced to a small (1-13, depending on the region) number of soil-related classes (end-members) that could be used in climate models. We also addressed the temporal evolution of albedo during 2001 over global deserts. Regions/soils of stable albedo with very low temporal variability were identified. For other regions/soils, temporal signals in albedo were related to ephemeral inundation with water or variations in sample size.

  5. Novel Multiplexer to Enable Multiple-Module Imaging with Adjustable High Spatial Resolution and Predetermined Display Bandwidth for Array Medical Imaging Systems.

    PubMed

    Sharma, P; Titus, A H; Qu, B; Huang, Y; Wang, W; Kuhls-Gilcrist, A; Cartwright, A N; Bednarek, D R; Rudin, S

    2010-01-01

    We describe a custom multiple-module multiplexer integrated circuit (MMMIC) that enables the combination of discrete Electron multiplying charge coupled devices (EMCCD) based imaging modules to improve medical imaging systems. It is highly desirable to have flexible imaging systems that provide high spatial resolution over a specific region of interest (ROI) and a field of view (FOV) large enough to encompass areas of clinical interest. Also, such systems should be dynamic, i.e. should be able to maintain a specified acquisition bandwidth irrespective of the size of the imaged FOV. The MMMIC achieves these goals by 1) multiplexing the outputs of an array of imaging modules to enable a larger FOV, 2) enabling a number of binning modes for adjustable high spatial resolution, and 3) enabling selection of a subset of modules in the array to achieve ROI imaging at a predetermined display bandwidth. The MMMIC design also allows multiple MMMICs to be connected to control larger arrays. The prototype MMMIC was designed and fabricated in the ON-SEMI 0.5μm CMOS process through MOSIS (www.mosis.org). It has three 12-bit inputs, a single 12-bit output, three input enable bits, and one output enable, so that one MMMIC can control the output from three discrete imager arrays. The modular design of the MMMIC enables four identical chips, connected in a two-stage sequential arrangement, to readout a 3×3 collection of individual imaging modules. The first stage comprises three MMMICs (each connected to three of the individual imaging module), and the second stage is a single MMMIC whose 12-bit output is then sent via a CameraLink interface to the system computer. The prototype MMMIC was successfully tested using digital outputs from two EMCCD-based detectors to be used in an x-ray imaging array detector system.Finally, we show how the MMMIC can be used to extend an imaging system to include any arbitrary (M×N) array of imaging modules enabling a large FOV along with ROI imaging

  6. Taheri-Saramad x-ray detector (TSXD): A novel high spatial resolution x-ray imager based on ZnO nano scintillator wires in polycarbonate membrane

    SciTech Connect

    Taheri, A. Saramad, S.; Ghalenoei, S.; Setayeshi, S.

    2014-01-15

    A novel x-ray imager based on ZnO nanowires is designed and fabricated. The proposed architecture is based on scintillation properties of ZnO nanostructures in a polycarbonate track-etched membrane. Because of higher refractive index of ZnO nanowire compared to the membrane, the nanowire acts as an optical fiber that prevents the generated optical photons to spread inside the detector. This effect improves the spatial resolution of the imager. The detection quantum efficiency and spatial resolution of the fabricated imager are 11% and <6.8 μm, respectively.

  7. Dem Reconstruction Using Light Field and Bidirectional Reflectance Function from Multi-View High Resolution Spatial Images

    NASA Astrophysics Data System (ADS)

    de Vieilleville, F.; Ristorcelli, T.; Delvit, J.-M.

    2016-06-01

    This paper presents a method for dense DSM reconstruction from high resolution, mono sensor, passive imagery, spatial panchromatic image sequence. The interest of our approach is four-fold. Firstly, we extend the core of light field approaches using an explicit BRDF model from the Image Synthesis community which is more realistic than the Lambertian model. The chosen model is the Cook-Torrance BRDF which enables us to model rough surfaces with specular effects using specific material parameters. Secondly, we extend light field approaches for non-pinhole sensors and non-rectilinear motion by using a proper geometric transformation on the image sequence. Thirdly, we produce a 3D volume cost embodying all the tested possible heights and filter it using simple methods such as Volume Cost Filtering or variational optimal methods. We have tested our method on a Pleiades image sequence on various locations with dense urban buildings and report encouraging results with respect to classic multi-label methods such as MIC-MAC, or more recent pipelines such as S2P. Last but not least, our method also produces maps of material parameters on the estimated points, allowing us to simplify building classification or road extraction.

  8. Soft X-Ray Microscopy and EUV Lithography: An Update on Imaging at 20-40 nm Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Attwood, D.; Anderson, E.; Denbeaux, G.; Goldberg, K.; Naulleau, P.; Schneider, G.

    2002-11-01

    Major advances in both soft x-ray microscopy, at wavelengths from 0.6 to 4 nm, and EUV lithography, at wavelengths between 13 and 14 nm, are reviewed. In the XRL-2000 proceedings we reported soft x-ray microscopy resolved to 25 nm, in static two-dimensional imaging, with applications to biology, magnetic materials, and various "wet" environmental samples. In this 2002 update we report significant extensions to three-dimensional tomographic imaging, dynamical studies of magnetic and electronic devices, and static two-dimensional microscopy poised for extension to below 20 nm spatial resolution. In the XRL-2000 proceedings we reported EUV lithographic imaging of 50 nm lines/100 nm spaces in static microfield (approx100 mum) exposures. In this 2002 update we report scanned full-field (25 mm by 32 mm) images at better than 100 nm lines/100 nm spaces, static microfield exposures down to 50 nm lines/50 nm spaces, and isolated lines to 39 nm wide at 0.1 NA. With soon to be available 0.3 NA optics, we expect to print isolated lines, in static micro exposures, at 16-20 nm width in 2003. These results will demonstrate EUV lithography's ability to meet not only the ITRS Roadmap 45 nm node (26 nm isolated lines in resist) in 2007, but also the 32 nm node (18 nm isolated lines in resist) in 2009, both of which the semiconductor industry is now preparing for.

  9. An Efficient Approach for Pixel Decomposition to Increase the Spatial Resolution of Land Surface Temperature Images from MODIS Thermal Infrared Band Data

    PubMed Central

    Wang, Fei; Qin, Zhihao; Li, Wenjuan; Song, Caiying; Karnieli, Arnon; Zhao, Shuhe

    2015-01-01

    Land surface temperature (LST) images retrieved from the thermal infrared (TIR) band data of Moderate Resolution Imaging Spectroradiometer (MODIS) have much lower spatial resolution than the MODIS visible and near-infrared (VNIR) band data. The coarse pixel scale of MODIS LST images (1000 m under nadir) have limited their capability in applying to many studies required high spatial resolution in comparison of the MODIS VNIR band data with pixel scale of 250–500 m. In this paper we intend to develop an efficient approach for pixel decomposition to increase the spatial resolution of MODIS LST image using the VNIR band data as assistance. The unique feature of this approach is to maintain the thermal radiance of parent pixels in the MODIS LST image unchanged after they are decomposed into the sub-pixels in the resulted image. There are two important steps in the decomposition: initial temperature estimation and final temperature determination. Therefore the approach can be termed double-step pixel decomposition (DSPD). Both steps involve a series of procedures to achieve the final result of decomposed LST image, including classification of the surface patterns, establishment of LST change with normalized difference of vegetation index (NDVI) and building index (NDBI), reversion of LST into thermal radiance through Planck equation, and computation of weights for the sub-pixels of the resulted image. Since the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with much higher spatial resolution than MODIS data was on-board the same platform (Terra) as MODIS for Earth observation, an experiment had been done in the study to validate the accuracy and efficiency of our approach for pixel decomposition. The ASTER LST image was used as the reference to compare with the decomposed LST image. The result showed that the spatial distribution of the decomposed LST image was very similar to that of the ASTER LST image with a root mean square error (RMSE) of

  10. An efficient approach for pixel decomposition to increase the spatial resolution of land surface temperature images from MODIS thermal infrared band data.

    PubMed

    Wang, Fei; Qin, Zhihao; Li, Wenjuan; Song, Caiying; Karnieli, Arnon; Zhao, Shuhe

    2015-01-01

    Land surface temperature (LST) images retrieved from the thermal infrared (TIR) band data of Moderate Resolution Imaging Spectroradiometer (MODIS) have much lower spatial resolution than the MODIS visible and near-infrared (VNIR) band data. The coarse pixel scale of MODIS LST images (1000 m under nadir) have limited their capability in applying to many studies required high spatial resolution in comparison of the MODIS VNIR band data with pixel scale of 250-500 m. In this paper we intend to develop an efficient approach for pixel decomposition to increase the spatial resolution of MODIS LST image using the VNIR band data as assistance. The unique feature of this approach is to maintain the thermal radiance of parent pixels in the MODIS LST image unchanged after they are decomposed into the sub-pixels in the resulted image. There are two important steps in the decomposition: initial temperature estimation and final temperature determination. Therefore the approach can be termed double-step pixel decomposition (DSPD). Both steps involve a series of procedures to achieve the final result of decomposed LST image, including classification of the surface patterns, establishment of LST change with normalized difference of vegetation index (NDVI) and building index (NDBI), reversion of LST into thermal radiance through Planck equation, and computation of weights for the sub-pixels of the resulted image. Since the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) with much higher spatial resolution than MODIS data was on-board the same platform (Terra) as MODIS for Earth observation, an experiment had been done in the study to validate the accuracy and efficiency of our approach for pixel decomposition. The ASTER LST image was used as the reference to compare with the decomposed LST image. The result showed that the spatial distribution of the decomposed LST image was very similar to that of the ASTER LST image with a root mean square error (RMSE) of 2

  11. Spatial resolution and noise in organic light-emitting diode displays for medical imaging applications.

    PubMed

    Yamazaki, Asumi; Wu, Chih-Lei; Cheng, Wei-Chung; Badano, Aldo

    2013-11-18

    We report on the resolution and noise characteristics of handheld and workstation organic light-emitting diode (OLED) displays in comparison with liquid crystal displays (LCDs). The results demonstrate advantages, in terms of sharpness, of handheld OLED displays with modulation transfer function (MTF) values exceeding 0.60 at the Nyquist frequencies. The OLED workstation included in this study exhibits significant signal contamination among adjacent pixels resulting in degraded resolution performance indicated by horizontal and vertical MTF values of 0.13 and 0.24 at the Nyquist frequency. On the other hand, its noise characteristics are superior to the LCD workstation tested. While the noise power spectral (NPS) values of the OLED workstation are 8.0×10(-6) mm2 at 1 mm(-1), the LCD workstation has NPS values of 2.6×10(-5) mm2. Although phone-size OLED displays have superior resolution and noise per pixel, the perceived resolution characteristics at appropriate viewing distances are inferior to tablet-size and workstation LCDs. In addition, our results show some degree of dependency of the resolution and noise on luminance level and viewing orientation. We also found a slightly degraded resolution and increased low-frequency noise at off-normal orientations in the handheld displays. PMID:24514325

  12. Direct high-spatial-resolution SIMS (secondary ion mass spectrometry) imaging of labeled nucleosides in human chromosomes

    NASA Astrophysics Data System (ADS)

    Hallegot, Philippe; Girod, C.; LeBeau, M. M.; Levi-Setti, Riccardo

    1991-03-01

    Using a scanning ion microprobe we analyzed the distribution of labelled thymidine along human chromosomes. Two labels have been used: bromodeoxyuridine (BrdU which contains one bromine atom per molecule) and 14C-thymidine (which contains either one or ten 14C atoms per molecule). Both types of labelled nucleosides can be detected with our insirument. Best results are obtained when using the uniformly labelled thymidine (U-14C-thymidine) and adding up in a KONTRON IBAS image processing system the sequential analytical maps acquired from the sample at mass 28 (14C14N ions). The distribution of thymidine is heterogeneous along the chromosomes and a banding pattern can be observed on the pictures (SIMS-bands). The spatial resolution obtained with our scanning ion microprobe (the University of Chicago Scanning Ion Microprobe: UC-SIM) surpasses the one of autoradiography which is the common direct method of localization of labelled nucleosides. 1.

  13. How Attention Affects Spatial Resolution

    PubMed Central

    Carrasco, Marisa; Barbot, Antoine

    2015-01-01

    We summarize and discuss a series of psychophysical studies on the effects of spatial covert attention on spatial resolution, our ability to discriminate fine patterns. Heightened resolution is beneficial in most, but not all, visual tasks. We show how endogenous attention (voluntary, goal driven) and exogenous attention (involuntary, stimulus driven) affect performance on a variety of tasks mediated by spatial resolution, such as visual search, crowding, acuity, and texture segmentation. Exogenous attention is an automatic mechanism that increases resolution regardless of whether it helps or hinders performance. In contrast, endogenous attention flexibly adjusts resolution to optimize performance according to task demands. We illustrate how psychophysical studies can reveal the underlying mechanisms of these effects and allow us to draw linking hypotheses with known neurophysiological effects of attention. PMID:25948640

  14. Correction to ``Extracting Man-Made Objects From High Spatial Resolution Remote Sensing Images via Fast Level Set Evolutions''

    NASA Astrophysics Data System (ADS)

    Li, Zhongbin; Shi, Wenzhong; Wang, Qunming; Miao, Zelang

    2015-10-01

    Object extraction from remote sensing images has long been an intensive research topic in the field of surveying and mapping. Most existing methods are devoted to handling just one type of object and little attention has been paid to improving the computational efficiency. In recent years, level set evolution (LSE) has been shown to be very promising for object extraction in the community of image processing and computer vision because it can handle topological changes automatically while achieving high accuracy. However, the application of state-of-the-art LSEs is compromised by laborious parameter tuning and expensive computation. In this paper, we proposed two fast LSEs for man-made object extraction from high spatial resolution remote sensing images. The traditional mean curvature-based regularization term is replaced by a Gaussian kernel and it is mathematically sound to do that. Thus a larger time step can be used in the numerical scheme to expedite the proposed LSEs. In contrast to existing methods, the proposed LSEs are significantly faster. Most importantly, they involve much fewer parameters while achieving better performance. The advantages of the proposed LSEs over other state-of-the-art approaches have been verified by a range of experiments.

  15. Imaging shock waves in diamond with both high temporal and spatial resolution at an XFEL

    SciTech Connect

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-06-18

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.

  16. Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL

    NASA Astrophysics Data System (ADS)

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-06-01

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.

  17. Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL

    PubMed Central

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; Wark, Justin S.; Lee, Hae Ja; Nagler, Bob; Galtier, Eric C.; Arnold, Brice; Zastrau, Ulf; Hastings, Jerome B.; Schroer, Christian G.

    2015-01-01

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions. PMID:26086176

  18. Super-Spatial- and -Spectral-Resolution in Vibrational Imaging via Saturated Coherent Anti-Stokes Raman Scattering

    NASA Astrophysics Data System (ADS)

    Yonemaru, Yasuo; Palonpon, Almar F.; Kawano, Shogo; Smith, Nicholas I.; Kawata, Satoshi; Fujita, Katsumasa

    2015-07-01

    We demonstrate a vibrational microscopy technique with subdiffraction spatial resolution by the use of saturation of coherent anti-Stokes Raman scattering (CARS). The saturated CARS signals effectively produce a reduced point-spread function at harmonic frequencies, which is extracted by temporal modulation of the pump beam and demodulation of the CARS signal. An increase in spectral resolution and suppression of the nonresonant background signal accompany the spatial- resolution enhancement. Our simple, enhanced CARS technique promises to be useful in studying molecules in gas and liquid phases as well as soft condensed-matter systems.

  19. A poly(dimethylsiloxane)-based device enabling time-lapse imaging with high spatial resolution

    SciTech Connect

    Hirano, Masahiko; Hoshida, Tetsushi; Sakaue-Sawano, Asako; Miyawaki, Atsushi

    2010-02-12

    We have developed a regulator-free device that enables long-term incubation of mammalian cells for epi-fluorescence imaging, based on a concept that the size of sample to be gassed and heated is reduced to observation scale. A poly(dimethylsiloxane) block stamped on a coverslip works as a long-lasting supplier of CO{sub 2}-rich gas to adjust bicarbonate-containing medium in a tiny chamber at physiological pH, and an oil-immersion objective warms cells across the coverslip. A time-lapse imaging experiment using HeLa cells stably expressing fluorescent cell-cycle indicators showed that the cells in the chamber proliferated with normal cell-cycle period over 2 days.

  20. A DOI Detector With Crystal Scatter Identification Capability for High Sensitivity and High Spatial Resolution PET Imaging

    PubMed Central

    Gu, Z.; Prout, D. L.; Silverman, R. W.; Herman, H.; Dooraghi, A.; Chatziioannou, A. F.

    2015-01-01

    A new phoswich detector is being developed at the Crump Institute, aiming to provide improvements in sensitivity, and spatial resolution for PET. The detector configuration is comprised of two layers of pixelated scintillator crystal arrays, a glass light guide and a light detector. The annihilation photon entrance (top) layer is a 48 × 48 array of 1.01 × 1.01 × 7 mm3 LYSO crystals. The bottom layer is a 32 × 32 array of 1.55 × 1.55 × 9 mm3 BGO crystals. A tapered, multiple-element glass lightguide is used to couple the exit end of the BGO crystal array (52 × 52 mm2) to the photosensitive area of the Position Sensitive Photomultiplier Tube (46 × 46 mm2), allowing the creation of flat panel detectors without gaps between the detector modules. Both simulations and measurements were performed to evaluate the characteristics and benefits of the proposed design. The GATE Monte Carlo simulation indicated that the total fraction of the cross layer crystal scatter (CLCS) events in singles detection mode for this detector geometry is 13.2%. The large majority of these CLCS events (10.1% out of 13.2%) deposit most of their energy in a scintillator layer other than the layer of first interaction. Identification of those CLCS events for rejection or correction may lead to improvements in data quality and imaging performance. Physical measurements with the prototype detector showed that the LYSO, BGO and CLCS events were successfully identified using the delayed charge integration (DCI) technique, with more than 95% of the LYSO and BGO crystal elements clearly resolved. The measured peak-to-valley ratios (PVR) in the flood histograms were 3.5 for LYSO and 2.0 for BGO. For LYSO, the energy resolution ranged from 9.7% to 37.0% full width at half maximum (FWHM), with a mean of 13.4 ± 4.8%. For BGO the energy resolution ranged from 16.0% to 33.9% FWHM, with a mean of 18.6 ± 3.2%. In conclusion, these results demonstrate that the proposed detector is feasible and can

  1. Imaging shock waves in diamond with both high temporal and spatial resolution at an XFEL

    DOE PAGESBeta

    Schropp, Andreas; Hoppe, Robert; Meier, Vivienne; Patommel, Jens; Seiboth, Frank; Ping, Yuan; Hicks, Damien G.; Beckwith, Martha A.; Collins, Gilbert W.; Higginbotham, Andrew; et al

    2015-06-18

    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnifiedmore » x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.« less

  2. Effect of different spatial resolution of satellite image to observe the forest condition using satellite image and National Forest Inventory data

    NASA Astrophysics Data System (ADS)

    Kajisa, T.; Mizoue, N.; Yoshida, S.

    2010-12-01

    One of the most substantial needs in forest management planning is information about the condition of the forest. Strategic decisions concerning timber policies, decisions about timing and spatial extent of forest operations, and operational decisions such as work plans are all examples where accurate information of the forest conditions are required. Landsat has played the important role for land cover observation in the past, but, got a serious problem. Currently, many kinds of satellite image are available to monitor land cover. So, the utility of different types of satellite image have to be evaluated for land cover monitoring. On the other hands, in Japan, National Forest Inventory (NFI) has been conducted since 1999 with the aim of understanding the state and dynamics of various aspects in forests such as wood production and biodiversity throughout the country. However, few studies have been conducted to combine the satellite image and NFI data. Therefore, the objective of this study was to evaluate the effect of different spatial resolution of satellite image to observe the forest condition (forest/non-forest, forest types, forest stand volume) using satellite image and NFI data.

  3. The effect of acquisition interval and spatial resolution on dynamic cardiac imaging with a stationary SPECT camera.

    PubMed

    Roberts, J; Maddula, R; Clackdoyle, R; DiBella, E; Fu, Z

    2007-08-01

    The current SPECT scanning paradigm that acquires images by slow rotation of multiple detectors in body-contoured orbits around the patient is not suited to the rapid collection of tomographically complete data. During rapid image acquisition, mechanical and patient safety constraints limit the detector orbit to circular paths at increased distances from the patient, resulting in decreased spatial resolution. We consider a novel dynamic rotating slant-hole (DyRoSH) SPECT camera that can collect full tomographic data every 2 s, employing three stationary detectors mounted with slant-hole collimators that rotate at 30 rpm. Because the detectors are stationary, they can be placed much closer to the patient than is possible with conventional SPECT systems. We propose that the decoupling of the detector position from the mechanics of rapid image acquisition offers an additional degree of freedom which can be used to improve accuracy in measured kinetic parameter estimates. With simulations and list-mode reconstructions, we consider the effects of different acquisition intervals on dynamic cardiac imaging, comparing a conventional three detector SPECT system with the proposed DyRoSH SPECT system. Kinetic parameters of a two-compartment model of myocardial perfusion for technetium-99m-teboroxime were estimated. When compared to a conventional SPECT scanner for the same acquisition periods, the proposed DyRoSH system shows equivalent or reduced bias or standard deviation values for the kinetic parameter estimates. The DyRoSH camera with a 2 s acquisition period does not show any improvement compared to a DyRoSH camera with a 10 s acquisition period. PMID:17634648

  4. Hyperthermically induced changes in high spectral and spatial resolution MR images of tumor tissue—a pilot study

    NASA Astrophysics Data System (ADS)

    Foxley, Sean; Fan, Xiaobing; River, Jonathan; Zamora, Marta; Markiewicz, Erica; Sokka, Shunmugavelu; Karczmar, Gregory S.

    2012-05-01

    This pilot study investigated the feasibility of using MRI based on BOLD (blood-oxygen-level-dependent) contrast to detect physiological effects of locally induced hyperthermia in a rodent tumor model. Nude mice bearing AT6.1 rodent prostate tumors inoculated in the hind leg were imaged using a 9.4 T scanner using a multi-gradient echo pulse sequence to acquire high spectral and spatial resolution (HiSS) data. Temperature increases of approximately 6 °C were produced in tumor tissue using fiber-optic-guided light from a 250 W halogen lamp. HiSS data were acquired over three slices through the tumor and leg both prior to and during heating. Water spectra were produced from these datasets for each voxel at each time point. Time-dependent changes in water resonance peak width were measured during 15 min of localized tumor heating. The results demonstrated that hyperthermia produced both significant increases and decreases in water resonance peak width. Average decreases in peak width were significantly larger in the tumor rim than in normal muscle (p = 0.04). The effect of hyperthermia in tumor was spatially heterogeneous, i.e. the standard deviation of the change in peak width was significantly larger in the tumor rim than in normal muscle (p = 0.005). Therefore, mild hyperthermia produces spatially heterogeneous changes in water peak width in both tumor and muscle. This may reflect heterogeneous effects of hyperthermia on local oxygenation. The peak width changes in tumor and muscle were significantly different, perhaps due to abnormal tumor vasculature and metabolism. Response to hyperthermia measured by MRI may be useful for identifying and/or characterizing suspicious lesions as well as guiding the development of new hyperthermia protocols.

  5. Hyperthermically induced changes in high spectral and spatial resolution MR images of tumor tissue – a pilot study

    PubMed Central

    Foxley, Sean; Fan, Xiaobing; River, Jonathan; Zamora, Marta; Markiewicz, Erica; Sokka, Shunmugavelu; Karczmar, Gregory S

    2012-01-01

    This pilot study investigated the feasibility of using MRI based on BOLD (blood oxygen level dependent) contrast to detect physiological effects of locally induced hyperthermia in a rodent tumor model. Nude mice bearing AT6.1 rodent prostate tumors inoculated in the hind leg were imaged at 9.4T scanner using a multi-gradient echo pulse sequence to acquire high spectral and spatial resolution (HiSS) data. Approximately 6 °C increases were produced locally in tumor tissue using fiber optic guided light from a 250 W halogen lamp. HiSS data were acquired over three slices through the tumor and leg both prior to and during heating. Water spectra were produced from these datasets for each voxel at each time point. Time dependent changes in water resonance peak width were measured during 15 minutes of localized tumor heating. The results demonstrated that hyperthermia produced both significant increases and decreases in water resonance peak width. Average decreases in peak width were significantly larger in the tumor rim than in normal muscle (p = 0.04). The effect of hyperthermia in tumor was spatially heterogeneous, i.e., the standard deviation of the change in peak width was significantly larger in the tumor rim than in normal muscle (p = 0.005). Therefore, mild hyperthermia produces spatially heterogeneous changes in water peak width in both tumor and muscle. This may reflect heterogeneous effects of hyperthermia on local oxygenation. The peak width changes in tumor and muscle were significantly different, perhaps due to abnormal tumor vasculature and metabolism. Response to hyperthermia measured by MRI may be useful for identifying and/or characterizing suspicious lesions as well as guiding development of new hyperthermia protocols. PMID:22504096

  6. Targeted Multiplex Imaging Mass Spectrometry in Transmission Geometry for Subcellular Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Thiery-Lavenant, Gwendoline; Zavalin, Andre I.; Caprioli, Richard M.

    2013-04-01

    Targeted multiplex imaging mass spectrometry utilizes several different antigen-specific primary antibodies, each directly labeled with a unique photocleavable mass tag, to detect multiple antigens in a single tissue section. Each photocleavable mass tag bound to an antibody has a unique molecular weight and can be readily ionized by laser desorption ionization mass spectrometry. This article describes a mass spectrometry method that allows imaging of targeted single cells within tissue using transmission geometry laser desorption ionization mass spectrometry. Transmission geometry focuses the laser beam on the back side of the tissue placed on a glass slide, providing a 2 μm diameter laser spot irradiating the biological specimen. This matrix-free method enables simultaneous localization at the sub-cellular level of multiple antigens using specific tagged antibodies. We have used this technology to visualize the co-expression of synaptophysin and two major hormones peptides, insulin and somatostatin, in duplex assays in beta and delta cells contained in a human pancreatic islet.

  7. Automated Verification of Spatial Resolution in Remotely Sensed Imagery

    NASA Technical Reports Server (NTRS)

    Davis, Bruce; Ryan, Robert; Holekamp, Kara; Vaughn, Ronald

    2011-01-01

    Image spatial resolution characteristics can vary widely among sources. In the case of aerial-based imaging systems, the image spatial resolution characteristics can even vary between acquisitions. In these systems, aircraft altitude, speed, and sensor look angle all affect image spatial resolution. Image spatial resolution needs to be verified with estimators that include the ground sample distance (GSD), the modulation transfer function (MTF), and the relative edge response (RER), all of which are key components of image quality, along with signal-to-noise ratio (SNR) and dynamic range. Knowledge of spatial resolution parameters is important to determine if features of interest are distinguishable in imagery or associated products, and to develop image restoration algorithms. An automated Spatial Resolution Verification Tool (SRVT) was developed to rapidly determine the spatial resolution characteristics of remotely sensed aerial and satellite imagery. Most current methods for assessing spatial resolution characteristics of imagery rely on pre-deployed engineered targets and are performed only at selected times within preselected scenes. The SRVT addresses these insufficiencies by finding uniform, high-contrast edges from urban scenes and then using these edges to determine standard estimators of spatial resolution, such as the MTF and the RER. The SRVT was developed using the MATLAB programming language and environment. This automated software algorithm assesses every image in an acquired data set, using edges found within each image, and in many cases eliminating the need for dedicated edge targets. The SRVT automatically identifies high-contrast, uniform edges and calculates the MTF and RER of each image, and when possible, within sections of an image, so that the variation of spatial resolution characteristics across the image can be analyzed. The automated algorithm is capable of quickly verifying the spatial resolution quality of all images within a data

  8. A study of factors limiting spatial resolution using a 25 micron pixel pitch direct-detection amorphous selenium imaging system

    NASA Astrophysics Data System (ADS)

    Scott, Chris C.; Allec, Nicholas; Karim, Karim S.

    2012-03-01

    An amorphous selenium direct detector with a 25 μm pixel pitch is studied for mammography and fluoroscopy applications. In this paper we analyze spatial resolution by examining the main contributions to the inherent modulation transfer function (MTF) of amorphous selenium, such as primary photoelectron range and x-ray beam obliquity; and determine their significance relative to aperture MTF. Improvements in spatial resolution provided by a move to a small pixel size are complicated by deep carrier trapping. Trapped carriers cause residual charge induction across the pixel plane. We examine the significance of this effect on spatial resolution. The potential improvements of moving from a larger pixel pitch to a 25 μm pixel pitch are studied, including all significant effects, at selected pixel pitches.

  9. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER): Data Products for the High Spatial Resolution Imager on NASA's EOS-AMI Platform

    NASA Technical Reports Server (NTRS)

    Abrams, M.

    1999-01-01

    The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is a high spatial resolution, multispectral imager with along-track stereo capabilities scheduled for launch on the first NASA spacecraft of the Earth Observing System (EOS AM-1) in mid-1999.

  10. Tissue protein imaging at 1 μm laser spot diameter for high spatial resolution and high imaging speed using transmission geometry MALDI TOF MS

    PubMed Central

    Zavalin, Andre; Yang, Junhai; Hayden, Kevin; Vestal, Marvin; Caprioli, Richard M.

    2015-01-01

    We have achieved protein imaging mass spectrometry capabilities at sub-cellular spatial resolution and at high acquisition speed by integrating a transmission geometry ion source with time of flight mass spectrometry. The transmission geometry principle allowed us to achieve a 1 μm laser spot diameter on target. A minimal raster step size of the instrument was 2.5 μm. Use of 2,5-dihydroxyacetophenone robotically sprayed on top of a tissue sample as a matrix together with additional sample preparation steps resulted in single pixel mass spectra from mouse cerebellum tissue sections having more than 20 peaks in a range 3–22 kDa. Mass spectrometry images were acquired in a standard step raster microprobe mode at 5 pixels/s and in a continuous raster mode at 40 pixels/s. PMID:25673247

  11. Next-generation technologies for spatial proteomics: Integrating ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR imaging mass spectrometry for protein analysis.

    PubMed

    Spraggins, Jeffrey M; Rizzo, David G; Moore, Jessica L; Noto, Michael J; Skaar, Eric P; Caprioli, Richard M

    2016-06-01

    MALDI imaging mass spectrometry is a powerful analytical tool enabling the visualization of biomolecules in tissue. However, there are unique challenges associated with protein imaging experiments including the need for higher spatial resolution capabilities, improved image acquisition rates, and better molecular specificity. Here we demonstrate the capabilities of ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR IMS platforms as they relate to these challenges. High spatial resolution MALDI-TOF protein images of rat brain tissue and cystic fibrosis lung tissue were acquired at image acquisition rates >25 pixels/s. Structures as small as 50 μm were spatially resolved and proteins associated with host immune response were observed in cystic fibrosis lung tissue. Ultra-high speed MALDI-TOF enables unique applications including megapixel molecular imaging as demonstrated for lipid analysis of cystic fibrosis lung tissue. Additionally, imaging experiments using MALDI FTICR IMS were shown to produce data with high mass accuracy (<5 ppm) and resolving power (∼75 000 at m/z 5000) for proteins up to ∼20 kDa. Analysis of clear cell renal cell carcinoma using MALDI FTICR IMS identified specific proteins localized to healthy tissue regions, within the tumor, and also in areas of increased vascularization around the tumor. PMID:27060368

  12. Monitoring Oilfield Operations and GHG Emissions Sources Using Object-based Image Analysis of High Resolution Spatial Imagery

    NASA Astrophysics Data System (ADS)

    Englander, J. G.; Brodrick, P. G.; Brandt, A. R.

    2015-12-01

    Fugitive emissions from oil and gas extraction have become a greater concern with the recent increases in development of shale hydrocarbon resources. There are significant gaps in the tools and research used to estimate fugitive emissions from oil and gas extraction. Two approaches exist for quantifying these emissions: atmospheric (or 'top down') studies, which measure methane fluxes remotely, or inventory-based ('bottom up') studies, which aggregate leakage rates on an equipment-specific basis. Bottom-up studies require counting or estimating how many devices might be leaking (called an 'activity count'), as well as how much each device might leak on average (an 'emissions factor'). In a real-world inventory, there is uncertainty in both activity counts and emissions factors. Even at the well level there are significant disagreements in data reporting. For example, some prior studies noted a ~5x difference in the number of reported well completions in the United States between EPA and private data sources. The purpose of this work is to address activity count uncertainty by using machine learning algorithms to classify oilfield surface facilities using high-resolution spatial imagery. This method can help estimate venting and fugitive emissions sources from regions where reporting of oilfield equipment is incomplete or non-existent. This work will utilize high resolution satellite imagery to count well pads in the Bakken oil field of North Dakota. This initial study examines an area of ~2,000 km2 with ~1000 well pads. We compare different machine learning classification techniques, and explore the impact of training set size, input variables, and image segmentation settings to develop efficient and robust techniques identifying well pads. We discuss the tradeoffs inherent to different classification algorithms, and determine the optimal algorithms for oilfield feature detection. In the future, the results of this work will be leveraged to be provide activity

  13. Passive imaging through the turbulent atmosphere - Fundamental limits on the spatial frequency resolution of a rotational shearing interferometer

    NASA Technical Reports Server (NTRS)

    Burke, J. J.; Breckinridge, J. B.

    1978-01-01

    The signal-to-noise (S/N) ratio to be expected when a 180 deg rotationally shearing interferometer is used for image recovery at the diffraction limit of a large telescope is computed. The variance and covariance of the irradiance fluctuations at the detector array are shown to yield measures of the high-frequency spatial spectrum of the source. Four fundamental sources of noise are considered: temporal fluctuations of the source, space-time fluctuations of the atmosphere, shot noise in the detected photocurrents, and the effects of finite sampling. S/N is found to be directly proportional to the angular resolution of the telescope, the single-frame integration time, the square root of the number of frames, the cube of the operating wavelength, the quantum efficiency of the detector, and the average spectral irradiance from the source on the pupil. It is inversely proportional to the cube of the field angle subtended by the source (or part thereof) under study.

  14. High Spatial Resolution Thermal Satellite Technologies

    NASA Technical Reports Server (NTRS)

    Ryan, Robert

    2003-01-01

    This document in the form of viewslides, reviews various low-cost alternatives to high spatial resolution thermal satellite technologies. There exists no follow-on to Landsat 7 or ASTER high spatial resolution thermal systems. This document reviews the results of the investigation in to the use of new technologies to create a low-cost useful alternative. Three suggested technologies are examined. 1. Conventional microbolometer pushbroom modes offers potential for low cost Landsat Data Continuity Mission (LDCM) thermal or ASTER capability with at least 60-120 ground sampling distance (GSD). 2. Backscanning could produce MultiSpectral Thermal Imager performance without cooled detectors. 3. Cooled detector could produce hyperspectral thermal class system or extremely high spatial resolution class instrument.

  15. Characterization of a CCD-based digital x-ray imaging system for small-animal studies: properties of spatial resolution.

    PubMed

    Ouandji, Fabrice; Potter, Eric; Chen, Wei R; Li, Yuhua; Tang, David; Liu, Hong

    2002-05-01

    A digital x-ray imaging system was designed for small-animal studies. This system is a fiber-optics taper-coupled imaging system with two CCD arrays uniquely jointed. The x-ray source of the system has a small focal spot of 20 microm. This digital imaging system contains specially designed shelves to provide magnification levels, ranging from 1.5x to 5x. The system is characterized in terms of its properties of spatial resolution. An observer-based spatial resolution measurement was conducted with a line-pair target and a sector test pattern. The modulation transfer function of the system, with different magnifications, was studied by use of a 10-microm lead slit. The average resolutions at 50% and 5% modulations at 1x magnification were measured as 3.9 and 8.4 lp/mm, respectively, where lp indicates line pairs. With 5x magnification, the 50% and the 5% modulations provided 13.2- and 29.9-lp/mm, respectively, average spatial resolutions. The measurements showed consistency between the two individual CCD arrays; the difference in resolution between the two CCDs is less than 1%, even at high magnifications. PMID:12009151

  16. HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEUTRON DETECTORS, Final Report for the Period November 1, 1999 - February 28, 2001

    SciTech Connect

    FISHER,RK

    2003-02-01

    OAK B202 HIGH SPATIAL RESOLUTION IMAGING OF INERTIAL FUSION TARGET PLASMAS USING BUBBLE NEUTRON DETECTORS. Bubble detectors, which can detect neutrons with a spatial 5 to 30 {micro}, are the most promising approach to imaging NIF target plasmas with the desired 5 {micro} spatial resolution in the target plane. Gel bubble detectors are being tested to record neutron images of ICF implosions in OMEGA experiments. By improving the noise reduction techniques used in analyzing the data taken in June 2000, we have been able to image the neutron emission from 6 {center_dot} 10{sup 13} yield DT target plasmas with a target plane spatial resolution of {approx} 140 {micro}. As expected, the spatial resolution was limited by counting statistics as a result of the low neutron detection efficiency of the easy-to-use gel bubble detectors. The results have been submitted for publication and will be the subject of an invited talk at the October 2001 Meeting of the Division of Plasma Physics of the American Physical Society. To improve the counting statistics, data was taken in May 2001 using a stack of four gel detectors and integrated over a series of up to seven high-yield DT shots. Analysis of the 2001 data is still in its early stages. Gel detectors were chosen for these initial tests since the bubbles can be photographed several hours after the neutron exposure. They consist of {approx} 5000 drops ({approx} 100 {micro} in diameter) of bubble detector liquid/cm{sup 3} suspended in an inactive support gel that occupies {approx} 99% of the detector volume. Using a liquid bubble chamber detector and a light scattering system to record the bubble locations a few microseconds after the neutron exposure when the bubbles are {approx} 10 {micro} in diameter, should result in {approx} 1000 times higher neutron detection efficiency and a target plane resolution on OMEGA of {approx} 10 to 50 {micro}.

  17. Robust and high resolution hyperpolarized metabolic imaging of the rat heart at 7 t with 3d spectral‐spatial EPI

    PubMed Central

    Miller, Jack J.; Lau, Angus Z.; Teh, Irvin; Schneider, Jürgen E.; Kinchesh, Paul; Smart, Sean; Ball, Vicky; Sibson, Nicola R.

    2015-01-01

    Purpose Hyperpolarized metabolic imaging has the potential to revolutionize the diagnosis and management of diseases where metabolism is dysregulated, such as heart disease. We investigated the feasibility of imaging rodent myocardial metabolism at high resolution at 7 T. Methods We present here a fly‐back spectral‐spatial radiofrequency pulse that sidestepped maximum gradient strength requirements and enabled high resolution metabolic imaging of the rodent myocardium. A 3D echo‐planar imaging readout followed, with centric ordered z‐phase encoding. The cardiac gated sequence was used to image metabolism in rodents whose metabolic state had been manipulated by being fasted, fed, or fed and given the pyruvate dehydrogenase kinase inhibitor dichloroacetate. Results We imaged hyperpolarized metabolites with a spatial resolution of 2×2×3.8 mm3 and a temporal resolution of 1.8 s in the rat heart at 7 T. Significant differences in myocardial pyruvate dehydrogenase flux were observed between the three groups of animals, concomitant with the known biochemistry. Conclusion The proposed sequence was able to image in vivo metabolism with excellent spatial resolution in the rat heart. The field of view enabled the simultaneous multi‐organ acquisition of metabolic information from the rat, which is of great utility for preclinical research in cardiovascular disease. Magn Reson Med 000:000–000, 2015. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. Magn Reson Med 75:1515–1524, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance. PMID:25991606

  18. Development of high-spatial and high-mass resolution mass spectrometric imaging (MSI) and its application to the study of small metabolites and endogenous molecules of plants

    SciTech Connect

    Jun, Ji Hyun

    2012-01-01

    High-spatial and high-mass resolution laser desorption ionization (LDI) mass spectrometric (MS) imaging technology was developed for the attainment of MS images of higher quality containing more information on the relevant cellular and molecular biology in unprecedented depth. The distribution of plant metabolites is asymmetric throughout the cells and tissues, and therefore the increase in the spatial resolution was pursued to reveal the localization of plant metabolites at the cellular level by MS imaging. For achieving high-spatial resolution, the laser beam size was reduced by utilizing an optical fiber with small core diameter (25 μm) in a vacuum matrix-assisted laser desorption ionization-linear ion trap (vMALDI-LTQ) mass spectrometer. Matrix application was greatly improved using oscillating capillary nebulizer. As a result, single cell level spatial resolution of ~ 12 μm was achieved. MS imaging at this high spatial resolution was directly applied to a whole Arabidopsis flower and the substructures of an anther and single pollen grains at the stigma and anther were successfully visualized. MS imaging of high spatial resolution was also demonstrated to the secondary roots of Arabidopsis thaliana and a high degree of localization of detected metabolites was successfully unveiled. This was the first MS imaging on the root for molecular species. MS imaging with high mass resolution was also achieved by utilizing the LTQ-Orbitrap mass spectrometer for the direct identification of the surface metabolites on the Arabidopsis stem and root and differentiation of isobaric ions having the same nominal mass with no need of tandem mass spectrometry (MS/MS). MS imaging at high-spatial and high-mass resolution was also applied to cer1 mutant of the model system Arabidopsis thaliana to demonstrate its usefulness in biological studies and reveal associated metabolite changes in terms of spatial distribution and/or abundances compared to those of wild-type. The spatial

  19. Spatial resolution in visual memory.

    PubMed

    Ben-Shalom, Asaf; Ganel, Tzvi

    2015-04-01

    Representations in visual short-term memory are considered to contain relatively elaborated information on object structure. Conversely, representations in earlier stages of the visual hierarchy are thought to be dominated by a sensory-based, feed-forward buildup of information. In four experiments, we compared the spatial resolution of different object properties between two points in time along the processing hierarchy in visual short-term memory. Subjects were asked either to estimate the distance between objects or to estimate the size of one of the objects' features under two experimental conditions, of either a short or a long delay period between the presentation of the target stimulus and the probe. When different objects were referred to, similar spatial resolution was found for the two delay periods, suggesting that initial processing stages are sensitive to object-based properties. Conversely, superior resolution was found for the short, as compared with the long, delay when features were referred to. These findings suggest that initial representations in visual memory are hybrid in that they allow fine-grained resolution for object features alongside normal visual sensitivity to the segregation between objects. The findings are also discussed in reference to the distinction made in earlier studies between visual short-term memory and iconic memory. PMID:25112394

  20. Inverse Kriging to Enhance Spatial Resolution of Imagery

    SciTech Connect

    Petrie, Gregg M. ); Heasler, Patrick G. ); Perry, Eileen M. ); Thompson, Sandra E. ); Daly, Don S. )

    2002-12-15

    We describe a unique approach to image resolution enhancement, inverse kriging (IK), which takes advantage of the spatial relationship between high- and low-resolution images within an area of overlap. Once established, this mathematical relationship then can be applied across the entire low-resolution image to significantly sharpen the image. The mathematical relationship uses the spatial correlations within the low-resolution image and between the low and high spatial-resolution imagery. Two of the most important requirements of the technique are that the images be co-registered well within the resolution of the larger pixels and that the spatial structure of the training area (where the spatial correlation statistics are compared) is similar to the structure of the remaining image area where it will be applied. Testing was performed using same-sensor and multi-sensor imagery. We show results that indicate that the method does improve the low spatial-resolution imagery. The selection of a training area spatial structure similar to the area being processed is important, as areas with different spatial structure (e.g., vegetation versus buildings and roads) will produce poor results. Comparisons with bilinear interpolation demonstrate that IK could be used as an improved interpolation tool, for example, in the image-registration process.

  1. The effect of spatial micro-CT image resolution and surface complexity on the morphological 3D analysis of open porous structures

    SciTech Connect

    Pyka, Grzegorz; Kerckhofs, Greet

    2014-01-15

    In material science microfocus X-ray computed tomography (micro-CT) is one of the most popular non-destructive techniques to visualise and quantify the internal structure of materials in 3D. Despite constant system improvements, state-of-the-art micro-CT images can still hold several artefacts typical for X-ray CT imaging that hinder further image-based processing, structural and quantitative analysis. For example spatial resolution is crucial for an appropriate characterisation as the voxel size essentially influences the partial volume effect. However, defining the adequate image resolution is not a trivial aspect and understanding the correlation between scan parameters like voxel size and the structural properties is crucial for comprehensive material characterisation using micro-CT. Therefore, the objective of this study was to evaluate the influence of the spatial image resolution on the micro-CT based morphological analysis of three-dimensional (3D) open porous structures with a high surface complexity. In particular the correlation between the local surface properties and the accuracy of the micro-CT-based macro-morphology of 3D open porous Ti6Al4V structures produced by selective laser melting (SLM) was targeted and revealed for rough surfaces a strong dependence of the resulting structure characteristics on the scan resolution. Reducing the surface complexity by chemical etching decreased the sensitivity of the overall morphological analysis to the spatial image resolution and increased the detection limit. This study showed that scan settings and image processing parameters need to be customized to the material properties, morphological parameters under investigation and the desired final characteristics (in relation to the intended functional use). Customization of the scan resolution can increase the reliability of the micro-CT based analysis and at the same time reduce its operating costs. - Highlights: • We examine influence of the image resolution

  2. Digitized neutron imaging with high spatial resolution at a low power research reactor: I. Analysis of detector performance

    NASA Astrophysics Data System (ADS)

    Zawisky, M.; Hameed, F.; Dyrnjaja, E.; Springer, J.

    2008-03-01

    Imaging techniques provide an indispensable tool for investigation of materials. Neutrons, due to their specific properties, offer a unique probe for many aspects of condensed matter. Neutron imaging techniques present a challenging experimental task, especially at a low power research reactor. The Atomic Institute with a 250 kW TRIGA MARK II reactor looks back at a long tradition in neutron imaging. Here we report on the advantages gained in a recent upgrade of the imaging instrument including the acquisition of a thin-plate scintillation detector, a single counting micro-channel plate detector, and an imaging plate detector in combination with a high resolution scanner. We analyze the strengths and limitations of each detector in the field of neutron radiography and tomography, and demonstrate that high resolution digitized imaging down to the 50 μm scale can be accomplished with weak beam intensities of 1.3×10 5 n/cm 2 s, if appropriate measures are taken for the inevitable extension of measurement times. In a separate paper we will present some promising first results from the fields of engineering and geology.

  3. Skeletal muscle fiber analysis by atmospheric pressure scanning microprobe matrix-assisted laser desorption/ionization mass spectrometric imaging at high mass and high spatial resolution.

    PubMed

    Tsai, Yu-Hsuan; Bhandari, Dhaka Ram; Garrett, Timothy J; Carter, Christy S; Spengler, Bernhard; Yost, Richard A

    2016-06-01

    Skeletal muscles are composed of heterogeneous muscle fibers with various fiber types. These fibers can be classified into different classes based on their different characteristics. MALDI mass spectrometric imaging (MSI) has been applied to study and visualize different metabolomics profiles of different fiber types. Here, skeletal muscles were analyzed by atmospheric pressure scanning microprobe MALDI-MSI at high spatial and high mass resolution. PMID:27198224

  4. Development of vertically aligned ZnO-nanowires scintillators for high spatial resolution x-ray imaging

    NASA Astrophysics Data System (ADS)

    Kobayashi, Masakazu; Komori, Jun; Shimidzu, Kaiji; Izaki, Masanobu; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio

    2015-02-01

    Newly designed scintillator of (0001)-oriented ZnO vertical nanowires (vnws) for X-ray imaging was prepared on a Ga-doped ZnO/soda-lime glass by electrodeposition, and the light emission feature was estimated in a synchrotron radiation facility. The ZnO-vnws scintillator revealed a strong light emission and improved resolution on CMOS image compared with that for the ZnO-layer scintillator, although the light emission performance was deteriorated in comparison to the Lu3Al5O12:Ce3+. The light emission property closely related to the nanostructure and the resultant photoluminescence characteristic.

  5. Development of vertically aligned ZnO-nanowires scintillators for high spatial resolution x-ray imaging

    SciTech Connect

    Kobayashi, Masakazu Komori, Jun; Shimidzu, Kaiji; Izaki, Masanobu; Uesugi, Kentaro; Takeuchi, Akihisa; Suzuki, Yoshio

    2015-02-23

    Newly designed scintillator of (0001)-oriented ZnO vertical nanowires (vnws) for X-ray imaging was prepared on a Ga-doped ZnO/soda-lime glass by electrodeposition, and the light emission feature was estimated in a synchrotron radiation facility. The ZnO-vnws scintillator revealed a strong light emission and improved resolution on CMOS image compared with that for the ZnO-layer scintillator, although the light emission performance was deteriorated in comparison to the Lu{sub 3}Al{sub 5}O{sub 12:}Ce{sup 3+}. The light emission property closely related to the nanostructure and the resultant photoluminescence characteristic.

  6. Enhancing spatial resolution of 18F positron imaging with the Timepix detector by classification of primary fired pixels using support vector machine

    NASA Astrophysics Data System (ADS)

    Wang, Qian; Liu, Zhen; Ziegler, Sibylle I.; Shi, Kuangyu

    2015-07-01

    Position-sensitive positron cameras using silicon pixel detectors have been applied for some preclinical and intraoperative clinical applications. However, the spatial resolution of a positron camera is limited by positron multiple scattering in the detector. An incident positron may fire a number of successive pixels on the imaging plane. It is still impossible to capture the primary fired pixel along a particle trajectory by hardware or to perceive the pixel firing sequence by direct observation. Here, we propose a novel data-driven method to improve the spatial resolution by classifying the primary pixels within the detector using support vector machine. A classification model is constructed by learning the features of positron trajectories based on Monte-Carlo simulations using Geant4. Topological and energy features of pixels fired by 18F positrons were considered for the training and classification. After applying the classification model on measurements, the primary fired pixels of the positron tracks in the silicon detector were estimated. The method was tested and assessed for [18F]FDG imaging of an absorbing edge protocol and a leaf sample. The proposed method improved the spatial resolution from 154.6   ±   4.2 µm (energy weighted centroid approximation) to 132.3   ±   3.5 µm in the absorbing edge measurements. For the positron imaging of a leaf sample, the proposed method achieved lower root mean square error relative to phosphor plate imaging, and higher similarity with the reference optical image. The improvements of the preliminary results support further investigation of the proposed algorithm for the enhancement of positron imaging in clinical and preclinical applications.

  7. High resolution laser imaging system

    NASA Astrophysics Data System (ADS)

    Kyle, Thomas G.

    1989-07-01

    Computations indicate that a synthetic aperture laser imaging system can provide images with 10-cm resolution at satellite ranges using a 10-W CW laser. When imaging satellites from the ground, the synthetic aperture system reduces atmospheric degradations. The system uses 20-cm diam receiver optics. The low laser power is made possible by using separate transmitter and receiver optics and coded pulses with a 50 percent transmitter duty cycle. The coded pulses are derived from Hadamard matrices for which there is an efficient algorithm to transform the received data into images. The synthetic aperture yields spatial resolutions independent of range, and the coded pulses result in an effective range dependence of r exp-2 instead of r exp-4.

  8. Positron Emission Tomography with improved spatial resolution

    SciTech Connect

    Drukier, A.K.

    1990-04-01

    Applied Research Corporation (ARC) proposed the development of a new class of solid state detectors called Superconducting Granular Detectors (SGD). These new detectors permit considerable improvements in medical imaging, e.g. Positron Emission Tomography (PET). The biggest impact of this technique will be in imaging of the brain. It should permit better clinical diagnosis of such important diseases as Altzheimer's or schizophrenia. More specifically, we will develop an improved PET-imager; a spatial resolution 2 mm may be achievable with SGD. A time-of-flight capability(t {approx} 100 psec) will permit better contrast and facilitate 3D imaging. In the following, we describe the results of the first 9 months of the development.

  9. HiSStology: High Spectral and Spatial Resolution Magnetic Resonance Imaging Detection of Vasculature Validated by Histology and Micro–Computed Tomography

    PubMed Central

    Haney, Chad R.; Pelizzari, Charles A.; Foxley, Sean; Zamora, Marta A.; Mustafi, Devkumar; Tretiakova, Maria; Li, Shihong; Fan, Xiaobing; Karczmar, Gregory S.

    2011-01-01

    High spectral and spatial resolution (HiSS) data, acquired with echo-planar spectroscopic imaging (EPSI), can be used to acquire water spectra from each small image voxel. These images are sensitive to changes in local susceptibility caused by superparamagnetic iron oxide particles (SPIO); therefore, we hypothesized that images derived from HiSS data are very sensitive to tumor neovasculature following injection of SPIO. Accurate image registration was used to validate HiSS detection of neovasculature with histology and micro–computed tomographic (microCT) angiography. Athymic nude mice and Copenhagen rats were inoculated with Dunning AT6.1 prostate tumor cells in the right hind limb. The tumor region was imaged pre– and post–intravenous injection of SPIO. Three-dimensional assemblies of the CD31-stained histologic slices of the mouse legs and the microCT images of the rat vascular casts were registered with EPSI. The average distance between HiSS-predicted regions of high vascular density on magnetic resonance imaging and CD31-stained regions on histology was 200 µm. Similarly, vessels identified by HiSS in the rat images coincided with vasculature in the registered microCT image. The data demonstrate a strong correlation between tumor vasculature identified using HiSS and two gold standards: histology and microCT angiography. PMID:21443840

  10. The application of line imaging velocimetry to provide high resolution spatially resolved velocity data in plate impact experiments

    NASA Astrophysics Data System (ADS)

    Philpott, M. K.; George, A.; Whiteman, G.; De'Ath, J.; Millett, J. C. F.

    2015-12-01

    A single streak camera line imaging velocimeter has been applied to Armco® iron plate impact experiments to study material response at the grain scale. The grain size and phase distribution were determined with electron back scatter diffraction. The optical system resolution and fringe size were optimised to suit the grain size distribution. Comparisons of the performance and merits of several analysis algorithms including the ‘Fourier transform’, ‘fringe tracking’, ‘quadrature’ and the ‘continuous wavelet transform’ have been made by application to synthetic data. Point heterodyne velocimetry measurements made at the same location on the target surface have been compared with the line imaging velocimetry data for confirmation.

  11. Object-oriented classification of a high-spatial resolution SPOT5 image for mapping geology and landforms of active volcanoes: Semeru case study, Indonesia

    NASA Astrophysics Data System (ADS)

    Kassouk, Zeineb; Thouret, Jean-Claude; Gupta, Avijit; Solikhin, Akhmad; Liew, Soo Chin

    2014-09-01

    The present work explores the object-oriented classification (OOC) of high-spatial resolution (HSR) satellite panchromatic imagery for mapping the geology of the persistently active Semeru volcano and its ring plain, east Java, Indonesia. A panchromatic SPOT5 image and a digital elevation model (DEM) have been used to identify geologic units, structures, landforms and deposits. The panchromatic image was georeferenced and enhanced using histogram equalization. The enhanced image was segmented into polygons using the EnviFx (©Exelis) Software. The polygons were delineated and classified on the basis of spectral (panchromatic hues and textures), topographic (slope, elevation) information and geologic/geomorphic processes. The validity of classification was evaluated by interpreting Google Earth images, aerial photographs and limited field observations. The classification consists of three hierarchical levels across the volcanic area of about 745 km2. The first operational spatial level includes seven large volcano domains based on the spectral content of the volcanic, tectonic and lithological structures, and principal catchments. The second operational level, based on contextual relationships (topography, drainage network, vegetation cover type, stratigraphy and slope dynamics), encompasses 20 geological units that range between 30 and 80 km2 in area. Among the units, the third operational level distinguishes as many as 47 geomorphological sub-units (0.25-25 km2) according to slope gradient, deposit type, mass-wasting process and weathering. The resulting map provides a detailed pattern of geologic and geomorphic features unlike previous geologic maps that identified only 11 stratigraphic units. We show that the high-spatial resolution panchromatic SPOT5 scene can help to safely map the geology and landforms of persistently active volcanoes such as Semeru. We have applied the OOC technique on one HSR GeoEye panchromatic image to map another active volcano, Merapi

  12. High Spatial and Temporal Resolution Dynamic Contrast-Enhanced Magnetic Resonance Angiography (CE-MRA) using Compressed Sensing with Magnitude Image Subtraction

    PubMed Central

    Rapacchi, Stanislas; Han, Fei; Natsuaki, Yutaka; Kroeker, Randall; Plotnik, Adam; Lehman, Evan; Sayre, James; Laub, Gerhard; Finn, J Paul; Hu, Peng

    2014-01-01

    Purpose We propose a compressed-sensing (CS) technique based on magnitude image subtraction for high spatial and temporal resolution dynamic contrast-enhanced MR angiography (CE-MRA). Methods Our technique integrates the magnitude difference image into the CS reconstruction to promote subtraction sparsity. Fully sampled Cartesian 3D CE-MRA datasets from 6 volunteers were retrospectively under-sampled and three reconstruction strategies were evaluated: k-space subtraction CS, independent CS, and magnitude subtraction CS. The techniques were compared in image quality (vessel delineation, image artifacts, and noise) and image reconstruction error. Our CS technique was further tested on 7 volunteers using a prospectively under-sampled CE-MRA sequence. Results Compared with k-space subtraction and independent CS, our magnitude subtraction CS provides significantly better vessel delineation and less noise at 4X acceleration, and significantly less reconstruction error at 4X and 8X (p<0.05 for all). On a 1–4 point image quality scale in vessel delineation, our technique scored 3.8±0.4 at 4X, 2.8±0.4 at 8X and 2.3±0.6 at 12X acceleration. Using our CS sequence at 12X acceleration, we were able to acquire dynamic CE-MRA with higher spatial and temporal resolution than current clinical TWIST protocol while maintaining comparable image quality (2.8±0.5 vs. 3.0±0.4, p=NS). Conclusion Our technique is promising for dynamic CE-MRA. PMID:23801456

  13. Layer-specific BOLD activation in awake monkey V1 revealed by ultra-high spatial resolution functional magnetic resonance imaging

    PubMed Central

    Chen, Gang; Wang, Feng; Gore, John C.; Roe, Anna W.

    2012-01-01

    The laminar structure of the cortex has previously been explored both in non-human primates and human subjects using high-resolution functional magnetic resonance imaging (fMRI). However, whether the spatial specificity of the blood-oxygenation-level-dependent (BOLD) fMRI is sufficiently high to reveal lamina specific organization in the cortex reliably is still unclear. In this study we demonstrate for the first time the detection of such layer-specific activation in awake monkeys at the spatial resolution of 200×200×1000 µm3 in a vertical 4.7T scanner. Results collected in trained monkeys are high in contrast-to-noise ratio and low in motion artifacts. Isolation of laminar activation was aided by choosing the optimal slice orientation and thickness using a novel pial vein pattern analysis derived from optical imaging. We found the percent change of GE-BOLD signal is the highest at a depth corresponding to layer IV. Changes in the middle layers (layer IV) were 30% greater than changes in the top layers (layers I–III), and 32% greater than the bottom layers (layers V/VI). The laminar distribution of BOLD signal correlates well with neural activity reported in the literature. Our results suggest the high intrinsic spatial resolution of GE-BOLD signal is sufficient for mapping sub-millimeter functional structures in awake monkeys. This degree of spatial specificity will be useful for mapping both laminar activations and columnar structures in the cerebral cortex. PMID:22960152

  14. Morphology of the nucleus of Comet 67P/Churyumov--Gerasimenko from stereo and high spatial resolution OSIRIS-NAC images

    NASA Astrophysics Data System (ADS)

    Lamy, P. L.; Groussin, O.; Romeuf, D.; Auger, A. T.; Jorda, L.; Capanna, C.; Faury, G.

    2015-12-01

    The Narrow Angle Camera (NAC) of the OSIRIS imaging system aboard ESA's Rosetta spacecraft has acquired images of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko at scales down to 0.2 m/pixel. We employ a variety of techniques to characterize its morphology. Digital terrain modeling (DTM), indispensable for quantitative morphological analysis is performed using stereophotoclinometry (SPC). Depending upon the observational coverage, the resolution of the DTMs exceeds 1 m in the most favorable cases. The ultimate stereographic analysis is performed by exploiting pairs of images able to produce anaglyphs whose spatial resolution surpasses that of the DTMs. Digital image filtering and contrast enhancement techniques are applied on the original images as appropriate. We first concentrate on the dust covered terrains possibly resulting from airfall deposits, on the quasi circular depressions or basins possibly connected to collapses of the underground terrain, and on large scarps that suggest extensive mass disruption. We pay special attention to lithologies that may give clues to the subsurface structure of the nucleus. Our ultimate goal is to understand the processes at work on the nucleus, directly or indirectly connected to its activity as there appears to a variety of processes far beyond what was classically considered in the past, for instance airfall deposits, surface dust transport, mass wasting, and insolation weathering.

  15. Morphology of the nucleus of Comet 67P/Churyumov-Gerasimenko from stereo and high spatial resolution OSIRIS-NAC images

    NASA Astrophysics Data System (ADS)

    Lamy, Philippe; Groussin, Olivier; Romeuf, David; Thomas, Nicolas; Auger, Anne-Thérèse; Jorda, Laurent; Gaskell, Robert; Capanna, Claire; Llebaria, Antoine

    2015-04-01

    The Narrow Angle Camera (NAC) of the OSIRIS imaging system aboard ESA's Rosetta spacecraft has acquired images of the surface of the nucleus of comet 67P/Churyumov-Gerasimenko at scales down to 0.2 m/pixel. We employ a variety of techniques to characterize its morphology. Digital terrain modeling (DTM), indispensable for quantitative morphological analysis is performed using stereophotoclinometry (SPC). Depending upon the observational coverage, the resolution of the DTMs exceed 1 m in the most favorable cases. The ultimate stereographic analysis is performed by exploiting pairs of images able to produce anaglyphs whose spatial resolution surpasses that of the DTMs. Digital image filtering and contrast enhancement techniques are applied on the original images as appropriate. We first concentrate on the dust covered terrains possibly resulting from airfall deposits, on the quasi-circular depressions or basins possibly connected to collapses of the underground terrain, and on large scarps that suggest extensive mass disruption. We pay special attention to lithologies that may give clues to the subsurface structure of the nucleus. Our ultimate goal is to understand the processes at work on the nucleus, directly or indirectly connected to its activity as there appears to a variety of processes far beyond what was classicaly considered in the past, for instance airfall deposits, surface dust transport, mass wasting, and insolation weathering.

  16. Mapping the vegetation colonization on recent lava flows using spectral unmixing of moderate spatial resolution satellite images: Nyamuragira volcano, D. R. Congo

    NASA Astrophysics Data System (ADS)

    Li, Long; Kervyn, Matthieu; Canters, Frank

    2014-05-01

    In volcanic areas, vegetation colonizes recently erupted lava flows and expands over time. The fraction of vegetation is therefore likely to provide information on lava flows' age. Individual lava flows are usually not well resolved on satellite imagery due to the coarse spatial resolution: one pixel on the imagery is a mixture of mainly lava and vegetation. In order to solve the mixed pixel problem, many different methods have been proposed among which linear spectral unmixing is the most widely-used. It assumes that the reflectance of the mixed pixel is the sum of the reflectance of each pure end members multiplied by their proportion in the pixel. It has been frequently used in urban area studies, but no efforts have yet been made to apply it to volcanic areas. Here, we demonstrate the application of linear spectral unmixing for the lava flows of Nyamuragira volcano, in the Virunga Volcanic province. Nyamuragira is an active volcano, emitting over 30 lava flows in the last 100 years. The limited access to the volcano due to social unrest in D. R. Congo justifies the value of remote sensing techniques. This shield volcano is exposed to tropical climate and thus vegetation colonizes lava flows rapidly. An EO-1 ALI image (Advanced land imager mounted on Earth Observing -1 Satellite) acquired over Nyamuragira on January 3, 2012 at spatial resolution of 30 m was processed with minimum noise fraction transform and end member extraction, and spectrally unmixed by linear mixture modelling technique into two types of lava, and one or two types of vegetation. The three end member model is better in terms of the RMSE and the expected spatial distribution of end members. A 2 m resolution Pleiades image acquired on January 21, 2013 and partly overlapping with the ALI image was taken as the reference image for validation. It was first classified using a supervised pixel-based classification technique and then compared to the proportion image derived from the ALI image

  17. Results of the spatial resolution simulation for multispectral data (resolution brochures)

    NASA Technical Reports Server (NTRS)

    1982-01-01

    The variable information content of Earth Resource products at different levels of spatial resolution and in different spectral bands is addressed. A low-cost brochure that scientists and laymen could use to visualize the effects of increasing the spatial resolution of multispectral scanner images was produced.

  18. SPECT imaging with resolution recovery

    SciTech Connect

    Bronnikov, A. V.

    2011-07-01

    Single-photon emission computed tomography (SPECT) is a method of choice for imaging spatial distributions of radioisotopes. Many applications of this method are found in nuclear industry, medicine, and biomedical research. We study mathematical modeling of a micro-SPECT system by using a point-spread function (PSF) and implement an OSEM-based iterative algorithm for image reconstruction with resolution recovery. Unlike other known implementations of the OSEM algorithm, we apply en efficient computation scheme based on a useful approximation of the PSF, which ensures relatively fast computations. The proposed approach can be applied with the data acquired with any type of collimators, including parallel-beam fan-beam, cone-beam and pinhole collimators. Experimental results obtained with a micro SPECT system demonstrate high efficiency of resolution recovery. (authors)

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  20. Spatial Phase Imaging

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Frequently, scientists grow crystals by dissolving a protein in a specific liquid solution, and then allowing that solution to evaporate. The methods used next have been, variously, invasive (adding a dye that is absorbed by the protein), destructive (crushing protein/salt-crystal mixtures and observing differences between the crushing of salt and protein), or costly and time-consuming (X-ray crystallography). In contrast to these methods, a new technology for monitoring protein growth, developed in part through NASA Small Business Innovation Research (SBIR) funding from Marshall Space Flight Center, is noninvasive, nondestructive, rapid, and more cost effective than X-ray analysis. The partner for this SBIR, Photon-X, Inc., of Huntsville, Alabama, developed spatial phase imaging technology that can monitor crystal growth in real time and in an automated mode. Spatial phase imaging scans for flaws quickly and produces a 3-D structured image of a crystal, showing volumetric growth analysis for future automated growth.

  1. Analyzing the Variation of Building Density Using High Spatial Resolution Satellite Images: the Example of Shanghai City

    PubMed Central

    Pan, Xian-Zhang; Zhao, Qi-Guo; Chen, Jie; Liang, Yin; Sun, Bo

    2008-01-01

    Building density is an important issue in urban planning and land management. In the article, building coverage ratio (BCR) and floor area ratio (FAR) values extracted from high resolution satellite images were used to indicate buildings’ stretching on the surface and growth along the third dimension within areas of interest in Shanghai City, P.R. China. The results show that the variation of FAR is higher than that of BCR in the inner circle, and that the newer commercial centers have higher FAR and lower BCR values, while the traditional commercial areas have higher FAR and BCR ratios. By comparing different residential areas, it was found that the historical “Shikumen” areas and the old residential areas built before 1980s have higher BCR and lower FAR, while the new residential areas have higher FAR and lower BCR, except for the villa areas. These results suggest that both older building areas and villa areas use land resources in an inefficient way, and therefore better planning and management of urban land are needed for those fast economic growing regions.

  2. High Spatial Resolution Mid-IR Imaging of V838 Monocerotis: Evidence of New Circumstellar Dust Creation

    NASA Technical Reports Server (NTRS)

    Winsiewski, John P.; Clampin, Mark; Bjorkman, Karen S.; Barry, Richard K.

    2008-01-01

    The eruptive variable V838 Monocerotis experienced three dramatic outbursts in early 2002. Its unexpectedly erratic photometric behavior wes matched by strong spectroscopic variability, in which the srar transitioned through the F, K, G spectral type s in 2002 February, reseabled a M5 supergiant by 2002 Aprll, and had a L-type super qiant spectram in 2002 October. The star is also infamous for producisg e spectacu lar light echo whose evolction has beer traced by HST/ACS. We report high sFatial resolution 11.2 and 18.1 micron imagicq of V838 Nonoceroris obrained with Genini Ob servatory's Klchelle in 2007 March. The 2007 flux density of the unresclved stellar core of is rouqhly 2 tixes brighter than zhaz observed in 2C04. We interpret tkese aata as evidecce t-at V838 Mon has experienced a new circumsellar dust creatioc evezt. We suggest that this newly c reated dust is Likely clumpy, and speculate that one (or ore) of Ekese clumps migh t have passed through the line-cf-sight in late 2036, prodccing the brief rnalti-wav elength pkotonetric event reported by Bond (2006) and Yunari ez a1 (2007). A gap o f spatially exzended therrrzl (18 micron) emission is present over radial distances of 1860 - 93000 AU from che central source. Assuming ejecta material expands at a constant velocity of 300-500 km/s, this gap suggests that no prior significanz circ unstellar dust production events have occurred withiin the past approx. 900-1500 years.

  3. Analysis of the 2006 block-and-ash flow deposits of Merapi Volcano, Java, Indonesia, using high-spatial resolution IKONOS images and complementary ground based observations

    NASA Astrophysics Data System (ADS)

    Thouret, Jean-Claude; Gupta, Avijit; Liew, Soo Chin; Lube, Gert; Cronin, Shane J.; Surono, Dr

    2010-05-01

    On 16 June 2006 an overpass of IKONOS coincided with the emplacement of an active block-and-ash flow fed by a lava dome collapse event at Merapi Volcano (Java, Indonesia). This was the first satellite image recorded for a moving pyroclastic flow. The very high-spatial resolution data displayed the extent and impact of the pyroclastic deposits emplaced during and prior to, the day of image acquisition. This allowed a number of features associated with high-hazard block-and-ash flows emplaced in narrow, deep gorges to be mapped, interpreted and understood. The block-and-ash flow and surge deposits recognized in the Ikonos images include: (1) several channel-confined flow lobes and tongues in the box-shaped valley; (2) thin ash-cloud surge deposit and knocked-down trees in constricted areas on both slopes of the gorge; (3) fan-like over bank deposits on the Gendol-Tlogo interfluves from which flows were re-routed in the Tlogo secondary valley; (4) massive over bank lobes on the right bank from which flows devastated the village of Kaliadem 0.5 km from the main channel, a small part of this flow being re-channeled in the Opak secondary valley. The high-resolution IKONOS images also helped us to identify geomorphic obstacles that enabled flows to ramp and spill out from the sinuous channel, a process called flow avulsion. Importantly, the avulsion redirected flows to unexpected areas away from the main channel. In the case of Merapi we see that the presence of valley fill by previous deposits, bends and man-made dams influence the otherwise valley-guided course of the flows. Sadly, Sabo dams (built to ameliorate the effect of high sediment load streams) can actually cause block-and-ash flows to jump out of their containing channel and advance into sensitive areas. Very-high-spatial resolution satellite images are very useful for mapping and interpreting the distribution of freshly erupted volcanic deposits. IKONOS-type images with 1-m resolution provide opportunities to

  4. Spatial Resolution Effects of Remote Sensing Informed Soil Nutrient Models Based on Landsat 8, RapidEye, WorldView-2 and GeoEye-1 Images

    NASA Astrophysics Data System (ADS)

    Xu, Y.; Grunwald, S.; Smith, S. E.; Abd-Elrahman, A.; Clingensmith, C. M.; Wani, S.

    2015-12-01

    Soil nutrient storage is essential and important to maintain food security and soil security in smallholder farm settings. The objective of this research was to analyze the spatial resolution effects of different remote sensing images on soil prediction models in Kothapally, India. We utilized Bayesian kriging (BK) to characterize the spatial pattern of total nitrogen (TN) and exchangeable potassium (Kex) in the topsoil (0-15 cm) at different spatial resolutions by incorporating spectral indices from Landsat 8 (30m), RapidEye (5m) and WorldView-2/GeoEye-1 images (2m). The band ratio of red to green, red to blue and green to blue, Crust Index and Atmospherically Resistant Vegetation Index from multiple images generally had high linear correlations with TN and Kex. The BK model of TN based on WorldView-2 and GeoEye-1 attained the highest model fit (R2=0.41) and lowest prediction error (RMSE=171.35 mg kg-1) compared with the BK models of TN based on Landsat 8 (R2=0.30; RMSE=182.26 mg kg-1) and RapidEye (R2=0.28; RMSE=183.52 mg kg-1). The BK model of Kex based on Landsat 8 had the highest model fit (R2=0.55) and the second lowest prediction error (RMSE=79.57 mg kg-1) compared with the BK models of Kex based on WorldView-2 and GeoEye-1 (R2=0.52; RMSE=79.42 mg kg-1) and RapidEye (R2=0.47; RMSE=83.91 mg kg-1). The lowest prediction fit and highest prediction error of soil TN and Kex models based on RapidEye suggest that the effect of fine spatial remote sensing spectral data inputs do not always lead to an increase of model fit. Soil maps based on WorldView-2 and GeoEye-1 have significant advantages in characterizing the variation of soil TN and Kex spatial pattern in smallholder farm settings compared with coarser maps. This research suggests that Digital Soil Mapping utilizing remote sensing spectral data from WorldView-2 and GeoEye-1 has high potential to be widely applied in smallholder farm settings and help smallholder farmers manage their soils and attain soil

  5. Single-Step 3-D Image Reconstruction in Magnetic Induction Tomography: Theoretical Limits of Spatial Resolution and Contrast to Noise Ratio

    PubMed Central

    Hollaus, Karl; Rosell-Ferrer, Javier; Merwa, Robert

    2006-01-01

    Magnetic induction tomography (MIT) is a low-resolution imaging modality for reconstructing the changes of the complex conductivity in an object. MIT is based on determining the perturbation of an alternating magnetic field, which is coupled from several excitation coils to the object. The conductivity distribution is reconstructed from the corresponding voltage changes induced in several receiver coils. Potential medical applications comprise the continuous, non-invasive monitoring of tissue alterations which are reflected in the change of the conductivity, e.g. edema, ventilation disorders, wound healing and ischemic processes. MIT requires the solution of an ill-posed inverse eddy current problem. A linearized version of this problem was solved for 16 excitation coils and 32 receiver coils with a model of two spherical perturbations within a cylindrical phantom. The method was tested with simulated measurement data. Images were reconstructed with a regularized single-step Gauss–Newton approach. Theoretical limits for spatial resolution and contrast/noise ratio were calculated and compared with the empirical results from a Monte-Carlo study. The conductivity perturbations inside a homogeneous cylinder were localized for a SNR between 44 and 64 dB. The results prove the feasibility of difference imaging with MIT and give some quantitative data on the limitations of the method. PMID:17031597

  6. Extending a prototype knowledge and object based image analysis model to coarser spatial resolution imagery: an example from the Missouri River

    USGS Publications Warehouse

    Strong, Laurence L.

    2012-01-01

    A prototype knowledge- and object-based image analysis model was developed to inventory and map least tern and piping plover habitat on the Missouri River, USA. The model has been used to inventory the state of sandbars annually for 4 segments of the Missouri River since 2006 using QuickBird imagery. Interpretation of the state of sandbars is difficult when images for the segment are acquired at different river stages and different states of vegetation phenology and canopy cover. Concurrent QuickBird and RapidEye images were classified using the model and the spatial correspondence of classes in the land cover and sandbar maps were analysed for the spatial extent of the images and at nest locations for both bird species. Omission and commission errors were low for unvegetated land cover classes used for nesting by both bird species and for land cover types with continuous vegetation cover and water. Errors were larger for land cover classes characterized by a mixture of sand and vegetation. Sandbar classification decisions are made using information on land cover class proportions and disagreement between sandbar classes was resolved using fuzzy membership possibilities. Regression analysis of area for a paired sample of 47 sandbars indicated an average positive bias, 1.15 ha, for RapidEye that did not vary with sandbar size. RapidEye has potential to reduce temporal uncertainty about least tern and piping plover habitat but would not be suitable for mapping sandbar erosion, and characterization of sandbar shapes or vegetation patches at fine spatial resolution.

  7. Extending a prototype knowledge- and object-based image analysis model to coarser spatial resolution imagery: an example from the Missouri River

    USGS Publications Warehouse

    Strong, Laurence L.

    2012-01-01

    A prototype knowledge- and object-based image analysis model was developed to inventory and map least tern and piping plover habitat on the Missouri River, USA. The model has been used to inventory the state of sandbars annually for 4 segments of the Missouri River since 2006 using QuickBird imagery. Interpretation of the state of sandbars is difficult when images for the segment are acquired at different river stages and different states of vegetation phenology and canopy cover. Concurrent QuickBird and RapidEye images were classified using the model and the spatial correspondence of classes in the land cover and sandbar maps were analysed for the spatial extent of the images and at nest locations for both bird species. Omission and commission errors were low for unvegetated land cover classes used for nesting by both bird species and for land cover types with continuous vegetation cover and water. Errors were larger for land cover classes characterized by a mixture of sand and vegetation. Sandbar classification decisions are made using information on land cover class proportions and disagreement between sandbar classes was resolved using fuzzy membership possibilities. Regression analysis of area for a paired sample of 47 sandbars indicated an average positive bias, 1.15 ha, for RapidEye that did not vary with sandbar size. RapidEye has potential to reduce temporal uncertainty about least tern and piping plover habitat but would not be suitable for mapping sandbar erosion, and characterization of sandbar shapes or vegetation patches at fine spatial resolution.

  8. Resolution limits in imaging LADAR systems

    NASA Astrophysics Data System (ADS)

    Khoury, Jed; Woods, Charles L.; Lorenzo, Joseph P.; Kierstead, John; Pyburn, Dana; Sengupta, S. K.

    2004-04-01

    In this paper, we introduce a new design concept of laser radar systems that combines both phase comparison and time-of-flight methods. We show from signal to noise ration considerations that there is a fundamental limit to the overall resolution in 3-D imaging range laser radar (LADAR). We introduce a new metric, volume of resolution (VOR), and we show from quantum noise considerations, that there is a maximum resolution volume, that can be achieved, for a given set of system parameters. Consequently, there is a direct tradeoff between range resolution and spatial resolution. Thus in a LADAR system, range resolution may be maximized at the expense of spatial image resolution and vice versa. We introduce resolution efficiency, ηr, as a new figure of merit for LADAR, that describes system resolution under the constraints of a specific design, compared to its optimal resolution performance derived from quantum noise considerations. We analyze how the resolution efficiency could be utilized to improve the resolution performance of a LADAR system. Our analysis could be extended to all LADAR systems, regardless of whether they are flash imaging or scanning laser systems.

  9. Coherent diffractive imaging: towards achieving atomic resolution.

    PubMed

    Dietze, S H; Shpyrko, O G

    2015-11-01

    The next generation of X-ray sources will feature highly brilliant X-ray beams that will enable the imaging of local nanoscale structures with unprecedented resolution. A general formalism to predict the achievable spatial resolution in coherent diffractive imaging, based solely on diffracted intensities, is provided. The coherent dose necessary to reach atomic resolution depends significantly on the atomic scale structure, where disordered or amorphous materials require roughly three orders of magnitude lower dose compared with the expected scaling of uniform density materials. Additionally, dose reduction for crystalline materials are predicted at certain resolutions based only on their unit-cell dimensions and structure factors. PMID:26524315

  10. Monitoring of the Spatial Distribution and Temporal Dynamics of the Green Vegetation Fraction of Croplands in Southwest Germany Using High-Resolution RapidEye Satellite Images

    NASA Astrophysics Data System (ADS)

    Imukova, Kristina; Ingwersen, Joachim; Streck, Thilo

    2014-05-01

    The green vegetation fraction (GVF) is a key input variable to the evapotranspiration scheme applied in the widely used NOAH land surface model (LSM). In standard applications of the NOAH LSM, the GVF is taken from a global map with a 15 km×15 km resolution. The central objective of the present study was (a) to derive gridded GVF data in a high spatial and temporal resolution from RapidEye images for a region in Southwest Germany, and (b) to improve the representation of the GVF dynamics of croplands in the NOAH LSM for a better simulation of water and energy exchange between land surface and atmosphere. For the region under study we obtained monthly RapidEye satellite images with a resolution 5 m×5 m by the German Aerospace Center (DLR). The images hold five spectral bands: blue, green, red, red-edge and near infrared (NIR). The GVF dynamics were determined based on the Normalized Difference Vegetation Index (NDVI) calculated from the red and near-infrared bands of the satellite images. The satellite GVF data were calibrated and validated against ground truth measurements. Digital colour photographs above the canopy were taken with a boom-mounted digital camera at fifteen permanently marked plots (1 m×1 m). Crops under study were winter wheat, winter rape and silage maize. The GVF was computed based on the red and the green band of the photographs according to Rundquist's method (2002). Based on the obtained calibration scheme GVF maps were derived in a monthly resolution for the region. Our results confirm a linear relationship between GVF and NDVI and demonstrate that it is possible to determine the GVF of croplands from RapidEye images based on a simple two end-member mixing model. Our data highlight the high variability of the GVF in time and space. At the field scale, the GVF was normally distributed with a coefficient of variation of about 32%. Variability was mainly caused by soil heterogeneities and management differences. At the regional scale the GVF

  11. A Very High Spatial Resolution Detector for Small Animal PET

    SciTech Connect

    Kanai Shah, M.S.

    2007-03-06

    Positron Emission Tomography (PET) is an in vivo analog of autoradiography and has the potential to become a powerful new tool in imaging biological processes in small laboratory animals. PET imaging of small animals can provide unique information that can help in advancement of human disease models as well as drug development. Clinical PET scanners used for human imaging are bulky, expensive and do not have adequate spatial resolution for small animal studies. Hence, dedicated, low cost instruments are required for conducting small animal studies with higher spatial resolution than what is currently achieved with clinical as well as dedicated small animal PET scanners. The goal of the proposed project is to investigate a new all solid-state detector design for small animal PET imaging. Exceptionally high spatial resolution, good timing resolution, and excellent energy resolution are expected from the proposed detector design. The Phase I project was aimed at demonstrating the feasibility of producing high performance solid-state detectors that provide high sensitivity, spatial resolution, and timing characteristics. Energy resolution characteristics of the new detector were also investigated. The goal of the Phase II project is to advance the promising solid-state detector technology for small animal PET and determine its full potential. Detectors modules will be built and characterized and finally, a bench-top small animal PET system will be assembled and evaluated.

  12. High spatial resolution (1.1 μm and 20 nm) FTIR polarization contrast imaging reveals pre-rupture disorder in damaged tendon.

    PubMed

    Wiens, Richard; Findlay, Catherine R; Baldwin, Samuel G; Kreplak, Laurent; Lee, J Michael; Veres, Samuel P; Gough, Kathleen M

    2016-06-23

    Collagen is a major constituent in many life forms; in mammals, collagen appears as a component of skin, bone, tendon and cartilage, where it performs critical functions. Vibrational spectroscopy methods are excellent for studying the structure and function of collagen-containing tissues, as they provide molecular insight into composition and organization. The latter is particularly important for collagenous materials, given that a key feature is their hierarchical, oriented structure, organized from molecular to macroscopic length scales. Here, we present the first results of high-resolution FTIR polarization contrast imaging, at 1.1 μm and 20 nm scales, on control and mechanically damaged tendon. The spectroscopic data are supported with parallel SEM and correlated AFM imaging. Our goal is to explore the changes induced in tendon after the application of damaging mechanical stress, and the consequences for the healing processes. The results and possibilities for the application of these high-spatial-resolution FTIR techniques in spectral pathology, and eventually in clinical applications, are discussed. PMID:27048856

  13. Simulation, optimization and testing of a novel high spatial resolution X-ray imager based on Zinc Oxide nanowires in Anodic Aluminium Oxide membrane using Geant4

    NASA Astrophysics Data System (ADS)

    Esfandi, F.; Saramad, S.

    2015-07-01

    In this work, a new generation of scintillator based X-ray imagers based on ZnO nanowires in Anodized Aluminum Oxide (AAO) nanoporous template is characterized. The optical response of ordered ZnO nanowire arrays in porous AAO template under low energy X-ray illumination is simulated by the Geant4 Monte Carlo code and compared with experimental results. The results show that for 10 keV X-ray photons, by considering the light guiding properties of zinc oxide inside the AAO template and suitable selection of detector thickness and pore diameter, the spatial resolution less than one micrometer and the detector detection efficiency of 66% are accessible. This novel nano scintillator detector can have many advantages for medical applications in the future.

  14. Super-resolution imaging of C-type lectin spatial rearrangement within the dendritic cell plasma membrane at fungal microbe contact sites

    NASA Astrophysics Data System (ADS)

    Itano, Michelle; Graus, Matthew; Pehlke, Carolyn; Wester, Michael; Liu, Ping; Lidke, Keith; Thompson, Nancy; Jacobson, Ken; Neumann, Aaron

    2014-08-01

    Dendritic cells express DC-SIGN and CD206, C-type lectins (CTLs) that bind a variety of pathogens and may facilitate pathogen uptake for subsequent antigen presentation. Both proteins form punctate membrane nanodomains (~80 nm) on naïve cells. We analyzed the spatiotemporal distribution of CTLs following host-fungal particle contact using confocal microscopy and three distinct methods of cluster identification and measurement of receptor clusters in super-resolution datasets: DBSCAN, Pair Correlation and a custom implementation of the Getis spatial statistic. Quantitative analysis of confocal and super-resolution images demonstrated that CTL nanodomains become concentrated in the contact site relative to non-contact membrane after the first hour of exposure and established that this recruitment is sustained out to four hours. DC-SIGN nanodomains in fungal contact sites exhibit a 70% area increase and a 38% decrease in interdomain separation. Contact site CD206 nanodomains possess 90% greater area and 42% lower interdomain separation relative to non-contact regions. Contact site CTL clusters appear as disk-shaped domains of approximately 150-175 nm in diameter. The increase in length scale of CTL nanostructure in contact sites suggests that the smaller nanodomains on resting membranes may merge during fungal nanodomain structure, or that they become packed closely enough to achieve sub-resolution inter-domain edge separations of < 30 nm. This study provides evidence of local receptor spatial rearrangements on the nanoscale that occur in the plasma membrane upon pathogen binding and may direct important signaling interactions required to recognize and respond to the presence of a relatively large pathogen.

  15. REFLECT: Logiciel de restitution des reflectances au sol pour l'amelioration de la qualite de l'information extraite des images satellitales a haute resolution spatiale

    NASA Astrophysics Data System (ADS)

    Bouroubi, Mohamed Yacine

    Multi-spectral satellite imagery, especially at high spatial resolution (finer than 30 m on the ground), represents an invaluable source of information for decision making in various domains in connection with natural resources management, environment preservation or urban planning and management. The mapping scales may range from local (finer resolution than 5 m) to regional (resolution coarser than 5m). The images are characterized by objects reflectance in the electromagnetic spectrum witch represents the key information in many applications. However, satellite sensor measurements are also affected by parasite input due to illumination and observation conditions, to the atmosphere, to topography and to sensor properties. Two questions have oriented this research. What is the best approach to retrieve surface reflectance with the measured values while taking into account these parasite factors? Is this retrieval a sine qua non condition for reliable image information extraction for the diverse domains of application for the images (mapping, environmental monitoring, landscape change detection, resources inventory, etc.)? The goals we have delineated for this research are as follow: (1) Develop software to retrieve ground reflectance while taking into account the aspects mentioned earlier. This software had to be modular enough to allow improvement and adaptation to diverse remote sensing application problems; and (2) Apply this software in various context (urban, agricultural, forest) and analyse results to evaluate the accuracy gain of extracted information from remote sensing imagery transformed in ground reflectance images to demonstrate the necessity of operating in this way, whatever the type of application. During this research, we have developed a tool to retrieve ground reflectance (the new version of the REFLECT software). This software is based on the formulas (and routines) of the 6S code (Second Simulation of Satellite Signal in the Solar Spectrum

  16. Modelisation spatiale du bassin versant Iroquois/Blanchette a partir des donnees LiDAR et d'image satellitaire a haute resolution spatiale

    NASA Astrophysics Data System (ADS)

    Maaref, Alaa

    2012-10-01

    This study aims to model pollution sources in the Iroquois / Blanchette watershed by using Lidar and RapidEye satellite imagery data to identify sites presenting risk to water quality. The study watershed covers an area of 92.4 km2 and is located in the north of the Edmundston municipality in northwestern New Brunswick, between 47°40 N and 47°45 N latitudes and 68°30 W and 68°40 W longitudes. Average summer and winter temperatures are 15.4° C and -7° C, respectively. In addition, winters are characterized by significant amounts of snowfall and the annual precipitation varies between 990 mm and 1200 mm, nearly one-third of which is in the form of snow. To achieve the stated objective, multisource data extracted from Lidar, RapidEye satellite imagery and field surveys were incorporated into the SWAT model. After radiometric and geometric corrections of the RapidEye satellite image, a supervised classification method based on the maximum likelihood was performed to obtain a landuse map of the study area, with average and overall accuracy levels of 90.45% and 95.24%, respectively. Lidar data were used to extract morphometric and hydrological parameters that were, together with meteorological and field data, introduced into the Revised Universal Soil Loss Equation adapted for Canada (RUSLE-CAN) and into the SWAT model for pollution risk assessment. The SWAT model was used and adapted for the purposes of this study. Results from the RUSLE-CAN equation modeling showed that soil loss in the watershed varies between 0.0025 tons / ha / year and 55.98 tons / ha / year. Simulations with the SWAT model generated monthly hydrographs in the watershed (subdivided into 21 sub-basins) as well as the spatial distribution of nitrate, phosphorus and E-Coli concentrations. The results obtained from this study helped to identify areas at risk of erosion and pollution in the Iroquois/Blanchette watershed, thus providing detailed and fine mapping of these areas. The derived

  17. Improving Nano-MRI Spatial Resolution with Phase Multiplexing

    NASA Astrophysics Data System (ADS)

    Moores, Brad; Eichler, Alex; Degen, Christian

    2015-03-01

    Magnetic resonance force microscopy (MRFM) is a scanning probe technique that allows measuring nuclear spin densities with resolution better than 10nm. Detecting such small volumes of spins (less than (10nm)3 corresponds to approximately 20,000 spins) requires long averaging of signals from statistically polarized nuclei. For instance, previous work demonstrated that imaging a single isotope (1H) of a Tobacco Mosaic Virus required averaging for 2 weeks, and therefore the chemical contrast abilities of MRFM had to be forfeited to enable higher spatial resolution. In order to reconcile the chemical selectivity of MRFM along with the proven high spatial resolution, we have developed a phase multiplexing technique capable of simultaneously acquiring spin signals from multiple isotopes and from up to six spatial locations. We have demonstrated this method using a nanowire test sample, and have achieved one-dimensional imaging resolution of less than 5 nm and subnanometer positional accuracy.

  18. The spatial resolution of epidemic peaks.

    PubMed

    Mills, Harriet L; Riley, Steven

    2014-04-01

    The emergence of novel respiratory pathogens can challenge the capacity of key health care resources, such as intensive care units, that are constrained to serve only specific geographical populations. An ability to predict the magnitude and timing of peak incidence at the scale of a single large population would help to accurately assess the value of interventions designed to reduce that peak. However, current disease-dynamic theory does not provide a clear understanding of the relationship between: epidemic trajectories at the scale of interest (e.g. city); population mobility; and higher resolution spatial effects (e.g. transmission within small neighbourhoods). Here, we used a spatially-explicit stochastic meta-population model of arbitrary spatial resolution to determine the effect of resolution on model-derived epidemic trajectories. We simulated an influenza-like pathogen spreading across theoretical and actual population densities and varied our assumptions about mobility using Latin-Hypercube sampling. Even though, by design, cumulative attack rates were the same for all resolutions and mobilities, peak incidences were different. Clear thresholds existed for all tested populations, such that models with resolutions lower than the threshold substantially overestimated population-wide peak incidence. The effect of resolution was most important in populations which were of lower density and lower mobility. With the expectation of accurate spatial incidence datasets in the near future, our objective was to provide a framework for how to use these data correctly in a spatial meta-population model. Our results suggest that there is a fundamental spatial resolution for any pathogen-population pair. If underlying interactions between pathogens and spatially heterogeneous populations are represented at this resolution or higher, accurate predictions of peak incidence for city-scale epidemics are feasible. PMID:24722420

  19. TRACE Images of the Solar Chromosphere, Transition Region, and Low Corona at High Cadence and High Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Tarbell, T. D.; Handy, B. N.; Judge, P. G.

    1999-05-01

    We present TRACE images and movies showing C IV emission (transition region at 80,000 degrees) and UV continuum (temperature minimum region) of quiet and active regions. TRACE images using the 1550, 1600, and 1700 Angstroms filters can be combined to estimate the total emission in the C IV 1548 and 1550 lines and the UV continuum. These are supplemented in different observations with MDI magnetograms, TRACE 171 Angstroms images (Fe IX/X and perhaps O VI), and SUMER spectra of chromospheric and transition region lines from SOHO JOP 72. In quiet sun, bright C IV transients are seen in the vicinity of flux emergence, flux cancellation, and less dramatic interactions of small magnetic structures. Some of these are accompanied by high-velocity explosive events seen in SUMER spectra. The C IV emission can be well-separated from the photospheric magnetic footpoints, suggesting that it takes place on current sheets higher in the atmosphere separating different flux systems. In active regions, both bright and dark fibrils or loops are seen in C IV. Many nano/micro/sub flares are seen, some but not all of which are associated with emerging flux. The C IV emission of "moss" regions, footpoints of hot coronal loops, is contrasted with that of similar plage which does not have hot loops above it. This work was supported by the NASA contracts and grants for TRACE, MDI, and SOHO.

  20. Solar system events at high spatial resolution

    SciTech Connect

    Baines, K H; Gavel, D T; Getz, A M; Gibbartd, S G; MacIntosh, B; Max, C E; McKay, C P; Young, E F; de Pater, I

    1999-02-19

    Until relatively recent advances in technology, astronomical observations from the ground were limited in image resolution by the blurring effects of earth's atmosphere. The blur extent, ranging typically from 0.5 to 2 seconds of arc at the best astronomical sights, precluded ground-based observations of the details of the solar system's moons, asteroids, and outermost planets. With the maturing of a high resolution image processing technique called speckle imaging the resolution limitation of the atmosphere can now be largely overcome. Over the past three years they have used speckle imaging to observe Titan, a moon of Saturn with an atmospheric density comparable to Earth's, Io, the volcanically active innermost moon of Jupiter, and Neptune, a gas giant outer planet which has continually changing planet-encircling storms. These observations were made at the world's largest telescope, the Keck telescope in Hawaii and represent the highest resolution infrared images of these objects ever taken.

  1. High Resolution Doppler Imager

    NASA Technical Reports Server (NTRS)

    Hays, Paul B.

    1999-01-01

    This report summarizes the accomplishments of the High Resolution Doppler Imager (HRDI) on UARS spacecraft during the period 4/l/96 - 3/31/99. During this period, HRDI operation, data processing, and data analysis continued, and there was a high level of vitality in the HRDI project. The HRDI has been collecting data from the stratosphere, mesosphere, and lower thermosphere since instrument activation on October 1, 1991. The HRDI team has stressed three areas since operations commenced: 1) operation of the instrument in a manner which maximizes the quality and versatility of the collected data; 2) algorithm development and validation to produce a high-quality data product; and 3) scientific studies, primarily of the dynamics of the middle atmosphere. There has been no significant degradation in the HRDI instrument since operations began nearly 8 years ago. HRDI operations are fairly routine, although we have continued to look for ways to improve the quality of the scientific product, either by improving existing modes, or by designing new ones. The HRDI instrument has been programmed to collect data for new scientific studies, such as measurements of fluorescence from plants, measuring cloud top heights, and lower atmosphere H2O.

  2. Fundamental limitations to the spatial resolution and flow volume that can be mapped using holographic particle image velocimetry

    NASA Astrophysics Data System (ADS)

    Coupland, Jeremy M.; Lobera Salazar, Julia; Halliwell, Neil A.

    2000-08-01

    We have recently proposed a variant of holographic particle image velocimetry (HPIV) to measure three-component measurements of fluid velocity throughout an extended flow volume. In essence the technique uses double exposure holography to record the positions of seeding particles at two, close spaced constants in time. Analysis of the resulting record is achieved by computing the auto (or cross) correlation of the complex amplitude distributions transmitted by a sampling aperture placed within a real, reconstruction of the holographic image. IN the case of sparsely seeded flows, it is straightforward to show that the field transmitted by the aperture is dominated by the particle images reconstructed close to the aperture itself and the measurement is therefore attributed to the instantaneous flow velocity at the centre of the aperture. As the seeding concentration is increased, however, a significant contribution of the transmitted field is due to light scattered from more distant particles. If significant velocity gradients exist, the contribution due to distant particles is largely un- correlated and the local particle displacement can be extracted even if the field is dominated by this component. If a significant proportion of the scattered light that passes from the aperture is collected from areas in the flow with similar velocity (for example from stagnant regions or light scattered from the flow vessel) then spurious peaks can occur in the correlation signal. This paper examines the limitations on the flow volume that can be mapped at a given seeding concentration and hence the fundamental limits on the number of velocity measurements that can be retrieved from a single recording.

  3. Retrieval of solar magnetic fields from high-spatial resolution filtergraph data: the Imaging Magnetograph eXperiment (IMaX)

    NASA Astrophysics Data System (ADS)

    Orozco Suárez, D.; Bellot Rubio, L. R.; Martínez Pillet, V.; Bonet, J. A.; Vargas Domínguez, S.; Del Toro Iniesta, J. C.

    2010-11-01

    Context. The design of modern instruments does not only imply thorough studies of instrumental effects but also a good understanding of the scientific analysis planned for the data. Aims: We investigate the reliability of Milne-Eddington (ME) inversions of high-resolution magnetograph measurements such as those to be obtained with the Imaging Magnetograph eXperiment (IMaX) aboard the Sunrise balloon. We also provide arguments to choose either Fe I 525.02 or 525.06 nm as the most suitable line for IMaX. Methods: We reproduce an IMaX observation using magnetoconvection simulations of the quiet Sun and synthesizing the four Stokes profiles emerging from them. The profiles are degraded by spatial and spectral resolution, noise, and limited wavelength sampling, just as real IMaX measurements. We invert these data and estimate the uncertainties in the retrieved physical parameters caused by the ME approximation and the spectral sampling. Results: It is possible to infer the magnetic field strength, inclination, azimuth, and line-of-sight velocity from standard IMaX measurements (4 Stokes parameters, 5 wavelength points, and a signal-to-noise ratio of 1000) applying ME inversions to any of the Fe I lines at 525 nm. We also find that telescope diffraction has important effects on the spectra coming from very high resolution observations of inhomogeneous atmospheres. Diffration reduces the amplitude of the polarization signals and changes the asymmetry of the Stokes profiles. Conclusions: The two Fe I lines at 525 nm meet the scientific requirements of IMaX, but Fe I 525.02 nm is to be preferred because it leads to smaller uncertainties in the retrieved parameters and offers a better detectability of the weakest (linear) polarization signals prevailing in the quiet Sun.

  4. High spatial resolution particle detectors

    DOEpatents

    Boatner, Lynn A.; Mihalczo, John T.

    2015-10-13

    Disclosed below are representative embodiments of methods, apparatus, and systems for detecting particles, such as radiation or charged particles. One exemplary embodiment disclosed herein is particle detector comprising an optical fiber with a first end and second end opposite the first end. The optical fiber of this embodiment further comprises a doped region at the first end and a non-doped region adjacent to the doped region. The doped region of the optical fiber is configured to scintillate upon interaction with a target particle, thereby generating one or more photons that propagate through the optical fiber and to the second end. Embodiments of the disclosed technology can be used in a variety of applications, including associated particle imaging and cold neutron scattering.

  5. High spatial resolution particle detectors

    DOEpatents

    Boatner, Lynn A.; Mihalczo, John T.

    2012-09-04

    Disclosed below are representative embodiments of methods, apparatus, and systems for detecting particles, such as radiation or charged particles. One exemplary embodiment disclosed herein is particle detector comprising an optical fiber with a first end and second end opposite the first end. The optical fiber of this embodiment further comprises a doped region at the first end and a non-doped region adjacent to the doped region. The doped region of the optical fiber is configured to scintillate upon interaction with a target particle, thereby generating one or more photons that propagate through the optical fiber and to the second end. Embodiments of the disclosed technology can be used in a variety of applications, including associated particle imaging and cold neutron scattering.

  6. Automated Wetland Delineation from Multi-Frequency and Multi-Polarized SAR Images in High Temporal and Spatial Resolution

    NASA Astrophysics Data System (ADS)

    Moser, L.; Schmitt, A.; Wendleder, A.

    2016-06-01

    Water scarcity is one of the main challenges posed by the changing climate. Especially in semi-arid regions where water reservoirs are filled during the very short rainy season, but have to store enough water for the extremely long dry season, the intelligent handling of water resources is vital. This study focusses on Lac Bam in Burkina Faso, which is the largest natural lake of the country and of high importance for the local inhabitants for irrigated farming, animal watering, and extraction of water for drinking and sanitation. With respect to the competition for water resources an independent area-wide monitoring system is essential for the acceptance of any decision maker. The following contribution introduces a weather and illumination independent monitoring system for the automated wetland delineation with a high temporal (about two weeks) and a high spatial sampling (about five meters). The similarities of the multispectral and multi-polarized SAR acquisitions by RADARSAT-2 and TerraSAR-X are studied as well as the differences. The results indicate that even basic approaches without pre-classification time series analysis or post-classification filtering are already enough to establish a monitoring system of prime importance for a whole region.

  7. Residual analysis of the water resonance signal in breast lesions imaged with high spectral and spatial resolution (HiSS) MRI: A pilot study

    SciTech Connect

    Weiss, William A. Medved, Milica; Karczmar, Gregory S.; Giger, Maryellen L.

    2014-01-15

    Purpose: High spectral and spatial resolution magnetic resonance imaging (HiSS MRI) yields information on the local environment of suspicious lesions. Previous work has demonstrated the advantages of HiSS (complete fat-suppression, improved image contrast, no required contrast agent, etc.), leading to initial investigations of water resonance lineshape for the purpose of breast lesion classification. The purpose of this study is to investigate a quantitative imaging biomarker, which characterizes non-Lorentzian components of the water resonance in HiSS MRI datasets, for computer-aided diagnosis (CADx). Methods: The inhomogeneous broadening and non-Lorentzian or “off-peak” components seen in the water resonance of proton spectra of breast HiSS images are analyzed by subtracting a Lorentzian fit from the water peak spectra and evaluating the difference spectrum or “residual.” The maxima of these residuals (referred to hereafter as “off-peak components”) tend to be larger in magnitude in malignant lesions, indicating increased broadening in malignant lesions. The authors considered only those voxels with the highest magnitude off-peak components in each lesion, with the number of selected voxels dependent on lesion size. Our voxel-based method compared the magnitudes and frequencies of off-peak components of all voxels from all lesions in a database that included 15 malignant and 8 benign lesions (yielding ∼3900 voxels) based on the lesions’ biopsy-confirmed diagnosis. Lesion classification was accomplished by comparing the average off-peak component magnitudes and frequencies in malignant and benign lesions. The area under the ROC curve (AUC) was used as a figure of merit for both the voxel-based and lesion-based methods. Results: In the voxel-based task of distinguishing voxels from malignant and benign lesions, off-peak magnitude yielded an AUC of 0.88 (95% confidence interval [0.84, 0.91]). In the lesion-based task of distinguishing malignant and

  8. Information extraction from high resolution satellite images

    NASA Astrophysics Data System (ADS)

    Yang, Haiping; Luo, Jiancheng; Shen, Zhanfeng; Xia, Liegang

    2014-11-01

    Information extracted from high resolution satellite images, such as roads, buildings, water and vegetation, has a wide range of applications in disaster assessment and environmental monitoring. At present, object oriented supervised learning is usually used in the objects identification from the high spatial resolution satellite images. In classical ways, we have to label some regions of interests from every image to be classified at first, which is labor intensive. In this paper, we build a feature base for information extraction in order to reduce the labeling efforts. The features stored are regulated and labeled. The labeled samples for a new coming image can be selected from the feature base. And the experiments are taken on GF-1 and ZY-3 images. The results show the feasibility of the feature base for image interpretation.

  9. Validation of modelled imaging plates sensitivity to 1-100 keV x-rays and spatial resolution characterisation for diagnostics for the "PETawatt Aquitaine Laser"

    NASA Astrophysics Data System (ADS)

    Boutoux, G.; Batani, D.; Burgy, F.; Ducret, J.-E.; Forestier-Colleoni, P.; Hulin, S.; Rabhi, N.; Duval, A.; Lecherbourg, L.; Reverdin, C.; Jakubowska, K.; Szabo, C. I.; Bastiani-Ceccotti, S.; Consoli, F.; Curcio, A.; De Angelis, R.; Ingenito, F.; Baggio, J.; Raffestin, D.

    2016-04-01

    Thanks to their high dynamic range and ability to withstand electromagnetic pulse, imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. In the framework of the development of the diagnostics for the Petawatt Aquitaine Laser facility, we present an absolute calibration and spatial resolution study of five different available types of IP (namely, MS-SR-TR-MP-ND) performed by using laser-induced K-shell X-rays emitted by a solid silver target irradiated by the laser ECLIPSE at CEntre Lasers Intenses et Applications. In addition, IP sensitivity measurements were performed with a 160 kV X-ray generator at CEA DAM DIF, where the absolute response of IP SR and TR has been calibrated to X-rays in the energy range 8-75 keV with uncertainties of about 15%. Finally, the response functions have been modeled in Monte Carlo GEANT4 simulations in order to reproduce experimental data. Simulations enable extrapolation of the IP response functions to photon energies from 1 keV to 1 GeV, of interest, e.g., for laser-driven radiography.

  10. Validation of modelled imaging plates sensitivity to 1-100 keV x-rays and spatial resolution characterisation for diagnostics for the "PETawatt Aquitaine Laser".

    PubMed

    Boutoux, G; Batani, D; Burgy, F; Ducret, J-E; Forestier-Colleoni, P; Hulin, S; Rabhi, N; Duval, A; Lecherbourg, L; Reverdin, C; Jakubowska, K; Szabo, C I; Bastiani-Ceccotti, S; Consoli, F; Curcio, A; De Angelis, R; Ingenito, F; Baggio, J; Raffestin, D

    2016-04-01

    Thanks to their high dynamic range and ability to withstand electromagnetic pulse, imaging plates (IPs) are commonly used as passive detectors in laser-plasma experiments. In the framework of the development of the diagnostics for the Petawatt Aquitaine Laser facility, we present an absolute calibration and spatial resolution study of five different available types of IP (namely, MS-SR-TR-MP-ND) performed by using laser-induced K-shell X-rays emitted by a solid silver target irradiated by the laser ECLIPSE at CEntre Lasers Intenses et Applications. In addition, IP sensitivity measurements were performed with a 160 kV X-ray generator at CEA DAM DIF, where the absolute response of IP SR and TR has been calibrated to X-rays in the energy range 8-75 keV with uncertainties of about 15%. Finally, the response functions have been modeled in Monte Carlo GEANT4 simulations in order to reproduce experimental data. Simulations enable extrapolation of the IP response functions to photon energies from 1 keV to 1 GeV, of interest, e.g., for laser-driven radiography. PMID:27131655