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

    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

  18. 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.

  19. 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

  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. 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

  1. 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.

  2. 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

  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. 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.

  18. 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.

  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. 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.

  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

    2016-06-01

    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.

  8. 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.

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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.

  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. 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.

  4. 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.

  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. 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.

  6. 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.

  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. 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

  17. 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

  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

    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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  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

    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.

  16. 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

  17. 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.

  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.

    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.

  5. 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.

  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

  11. Performance measurements of a high-spatial-resolution YAP camera.

    PubMed

    Uzunov, N; Bello, M; Boccaccio, P; Moschini, G; Baldazzi, G; Bollini, D; de Notaristefani, F; Mazzi, U; Riondato, M

    2005-02-01

    Physical properties of a position-sensitive camera for the analysis of biodistributions of gamma- and beta-emitting radiopharmaceuticals in small animals have been studied, in order to achieve optimal operating conditions. The camera consisted of a highly segmented yttrium-aluminate perovskite (YAP) scintillator, coupled to a position-sensitive photomultiplier. The energy resolution, the detection efficiency, the spatial resolution, the spatial linearity and the count-rate linearity of the YAP camera have been determined. Images related to initial activity levels and successive biodistribution evolution in mice organs are presented as an illustration of the camera performance. PMID:15773730

  12. Imaging Intracellular Fluorescent Proteins at Nanometer Resolution

    NASA Astrophysics Data System (ADS)

    Betzig, Eric; Patterson, George H.; Sougrat, Rachid; Lindwasser, O. Wolf; Olenych, Scott; Bonifacino, Juan S.; Davidson, Michael W.; Lippincott-Schwartz, Jennifer; Hess, Harald F.

    2006-09-01

    We introduce a method for optically imaging intracellular proteins at nanometer spatial resolution. Numerous sparse subsets of photoactivatable fluorescent protein molecules were activated, localized (to ~2 to 25 nanometers), and then bleached. The aggregate position information from all subsets was then assembled into a superresolution image. We used this method-termed photoactivated localization microscopy-to image specific target proteins in thin sections of lysosomes and mitochondria; in fixed whole cells, we imaged vinculin at focal adhesions, actin within a lamellipodium, and the distribution of the retroviral protein Gag at the plasma membrane.

  13. Reconstruction algorithm improving the spatial resolution of Micro-CT

    NASA Astrophysics Data System (ADS)

    Fu, Jian; Wei, Dongbo; Li, Bing; Zhang, Lei

    2008-03-01

    X-ray Micro computed tomography (Micro-CT) enables nondestructive visualization of the internal structure of objects with high-resolution images and plays an important role for industrial nondestructive testing, material evaluation and medical researches. Because the micro focus is much smaller than the ordinary focus, the geometry un-sharpness of Micro-CT projection is several decuples less than that of ordinary CT systems. So the scan conditions with high geometry magnification can be adopted to acquire the projection data with high sampling frequency. Based on this feature, a new filter back projection reconstruction algorithm is researched to improve the spatial resolution of Micro-CT. This algorithm permits the reconstruction center at any point on the line connecting the focus and the rotation center. It can reconstruct CT images with different geometry magnification by adjusting the position of the reconstruction center. So it can make the best of the above feature to improve the spatial resolution of Micro-CT. The computer simulation and the CT experiment of a special spatial resolution phantom are executed to check the validity of this method. The results demonstrate the effect of the new algorithm. Analysis shows that the spatial resolution can be improved 50%.

  14. Full Spatial Resolution Infrared Sounding Application in the Preconvection Environment

    NASA Astrophysics Data System (ADS)

    Liu, C.; Liu, G.; Lin, T.

    2013-12-01

    Advanced infrared (IR) sounders such as the Atmospheric Infrared Sounder (AIRS) and Infrared Atmospheric Sounding Interferometer (IASI) provide atmospheric temperature and moisture profiles with high vertical resolution and high accuracy in preconvection environments. The derived atmospheric stability indices such as convective available potential energy (CAPE) and lifted index (LI) from advanced IR soundings can provide critical information 1 ; 6 h before the development of severe convective storms. Three convective storms are selected for the evaluation of applying AIRS full spatial resolution soundings and the derived products on providing warning information in the preconvection environments. In the first case, the AIRS full spatial resolution soundings revealed local extremely high atmospheric instability 3 h ahead of the convection on the leading edge of a frontal system, while the second case demonstrates that the extremely high atmospheric instability is associated with the local development of severe thunderstorm in the following hours. The third case is a local severe storm that occurred on 7-8 August 2010 in Zhou Qu, China, which caused more than 1400 deaths and left another 300 or more people missing. The AIRS full spatial resolution LI product shows the atmospheric instability 3.5 h before the storm genesis. The CAPE and LI from AIRS full spatial resolution and operational AIRS/AMSU soundings along with Geostationary Operational Environmental Satellite (GOES) Sounder derived product image (DPI) products were analyzed and compared. Case studies show that full spatial resolution AIRS retrievals provide more useful warning information in the preconvection environments for determining favorable locations for convective initiation (CI) than do the coarser spatial resolution operational soundings and lower spectral resolution GOES Sounder retrievals. The retrieved soundings are also tested in a regional data assimilation WRF 3D-var system to evaluate the

  15. Spatial resolution requirements for automated cartographic road extraction

    USGS Publications Warehouse

    Benjamin, S.; Gaydos, L.

    1990-01-01

    Ground resolution requirements for detection and extraction of road locations in a digitized large-scale photographic database were investigated. A color infrared photograph of Sunnyvale, California was scanned, registered to a map grid, and spatially degraded to 1- to 5-metre resolution pixels. Road locations in each data set were extracted using a combination of image processing and CAD programs. These locations were compared to a photointerpretation of road locations to determine a preferred pixel size for the extraction method. Based on road pixel omission error computations, a 3-metre pixel resolution appears to be the best choice for this extraction method. -Authors

  16. Spatial, Temporal and Spectral Satellite Image Fusion via Sparse Representation

    NASA Astrophysics Data System (ADS)

    Song, Huihui

    Remote sensing provides good measurements for monitoring and further analyzing the climate change, dynamics of ecosystem, and human activities in global or regional scales. Over the past two decades, the number of launched satellite sensors has been increasing with the development of aerospace technologies and the growing requirements on remote sensing data in a vast amount of application fields. However, a key technological challenge confronting these sensors is that they tradeoff between spatial resolution and other properties, including temporal resolution, spectral resolution, swath width, etc., due to the limitations of hardware technology and budget constraints. To increase the spatial resolution of data with other good properties, one possible cost-effective solution is to explore data integration methods that can fuse multi-resolution data from multiple sensors, thereby enhancing the application capabilities of available remote sensing data. In this thesis, we propose to fuse the spatial resolution with temporal resolution and spectral resolution, respectively, based on sparse representation theory. Taking the study case of Landsat ETM+ (with spatial resolution of 30m and temporal resolution of 16 days) and MODIS (with spatial resolution of 250m ~ 1km and daily temporal resolution) reflectance, we propose two spatial-temporal fusion methods to combine the fine spatial information of Landsat image and the daily temporal resolution of MODIS image. Motivated by that the images from these two sensors are comparable on corresponding bands, we propose to link their spatial information on available Landsat- MODIS image pair (captured on prior date) and then predict the Landsat image from the MODIS counterpart on prediction date. To well-learn the spatial details from the prior images, we use a redundant dictionary to extract the basic representation atoms for both Landsat and MODIS images based on sparse representation. Under the scenario of two prior Landsat

  17. Lenses and effective spatial resolution in macroscopic optical mapping.

    PubMed

    Bien, Harold; Parikh, Puja; Entcheva, Emilia

    2007-02-21

    Optical mapping of excitation dynamically tracks electrical waves travelling through cardiac or brain tissue by the use of fluorescent dyes. There are several characteristics that set optical mapping apart from other imaging modalities: dynamically changing signals requiring short exposure times, dim fluorescence demanding sensitive sensors and wide fields of view (low magnification) resulting in poor optical performance. These conditions necessitate the use of optics with good light gathering ability, i.e. lenses having high numerical aperture. Previous optical mapping studies often used sensor resolution to estimate the minimum spatial feature resolvable, assuming perfect optics and infinite contrast. We examine here the influence of finite contrast and real optics on the effective spatial resolution in optical mapping under broad-field illumination for both lateral (in-plane) resolution and axial (depth) resolution of collected fluorescence signals. PMID:17264363

  18. High spatial resolution passive microwave sounding systems

    NASA Technical Reports Server (NTRS)

    Staelin, D. H.; Rosenkranz, P. W.; Bonanni, P. G.; Gasiewski, A. W.

    1986-01-01

    Two extensive series of flights aboard the ER-2 aircraft were conducted with the MIT 118 GHz imaging spectrometer together with a 53.6 GHz nadir channel and a TV camera record of the mission. Other microwave sensors, including a 183 GHz imaging spectrometer were flown simultaneously by other research groups. Work also continued on evaluating the impact of high-resolution passive microwave soundings upon numerical weather prediction models.

  19. A spatial-temporal-spectral blending model using satellite images

    NASA Astrophysics Data System (ADS)

    Zhang, L.; Fu, D.; Sun, X.; Chen, H.; She, X.

    2016-04-01

    Due to the budget and technical limitations, remote sensing sensor designs trade spatial resolution, swath width and spectral resolution. Consequently, no sensor can provide high spatial resolution, high temporal resolution and high spectral resolution simultaneously. However, the ability of Earth observation at fine resolution is urgently needed for global change science. One possible solution is to “blend” the reflectance from a variety of satellite data sources, including those providing high spatial resolution and less frequent coverage (e.g., Landsat Thematic Mapper, TM), daily global data (e.g., Moderate Resolution Imaging Spectroradiometer, MODIS), and high spectral resolution and infrequent revisit cycle (e.g., Hyperion). However, the previous algorithms for blending multi-source remotely sensed data have some shortcomings, especially with regard to hyperspectral information. This study has developed a SPAtial-Temporal-Spectral blending model (SPATS) that can simulate surface reflectance with high spatial-temporal-spectral resolution. SPATS is based on an existing spatial-temporal image blending model and a spatial-spectral image blending model. The performance of SPATS was tested with both simulated and observed satellite data, using Landsat TM, Hyperion and MODIS data, as well as heterogeneous landscapes as examples. The results show that the high spatial-temporal-spectral resolution reflectance data can be applied to investigations of global landscapes that are changing at different temporal scales.

  20. Subaru adaptive-optics high-spatial-resolution infrared K- and L'-band imaging search for deeply buried dual AGNs in merging galaxies

    SciTech Connect

    Imanishi, Masatoshi; Saito, Yuriko

    2014-01-01

    We present the results of infrared K- (2.2 μm) and L'-band (3.8 μm) high-spatial-resolution (<0.''2) imaging observations of nearby gas- and dust-rich infrared luminous merging galaxies, assisted by the adaptive optics system on the Subaru 8.2 m telescope. We investigate the presence and frequency of red K – L' compact sources, which are sensitive indicators of active galactic nuclei (AGNs), including AGNs that are deeply buried in gas and dust. We observed 29 merging systems and confirmed at least one AGN in all but one system. However, luminous dual AGNs were detected in only four of the 29 systems (∼14%), despite our method's being sensitive to buried AGNs. For multiple nuclei sources, we compared the estimated AGN luminosities with supermassive black hole (SMBH) masses inferred from large-aperture K-band stellar emission photometry in individual nuclei. We found that mass accretion rates onto SMBHs are significantly different among multiple SMBHs, such that larger-mass SMBHs generally show higher mass accretion rates when normalized to SMBH mass. Our results suggest that non-synchronous mass accretion onto SMBHs in gas- and dust-rich infrared luminous merging galaxies hampers the observational detection of kiloparsec-scale multiple active SMBHs. This could explain the significantly smaller detection fraction of kiloparsec-scale dual AGNs when compared with the number expected from simple theoretical predictions. Our results also indicate that mass accretion onto SMBHs is dominated by local conditions, rather than by global galaxy properties, reinforcing the importance of observations to our understanding of how multiple SMBHs are activated and acquire mass in gas- and dust-rich merging galaxies.

  1. Spatial resolution enhancement of EO-1 ALI bands

    NASA Astrophysics Data System (ADS)

    Nikolakopoulos, Konstantinos G.

    2006-09-01

    spectral characteristics, they do not take into account the resolution ratio of the input images. Usually the spatial resolution of the panchromatic image is two (Landsat 7, Spot 1-4) or four times (Ikonos, Quickbird) better than the size of the multispectral images. This paper is an attempt to fuse high-resolution panchromatic and low-resolution multispectral bands of the EO-1 ALI sensor. ALI collects nine multispectral bands with 30m resolution and a panchromatic band with 3 times better resolution (10m). ALI has a panchromatic band narrower than the respective band of Landsat7. It has also two narrower bands in the spectral range of Landsat7 band 4. It has also an extra narrower band near the spectral range of Landsat7 band 1. In this study we compare the efficiency of seven fusion techniques and more especially the efficiency of Gram Schmidt, Modified IHS, PCA, Pansharp, Wavelet and LMM (Local Mean Matching) LMVM (Local Mean and Variance Matching) fusion techniques for the fusion of ALI data. Two ALI images collected over the same area have been used. In order to quantitatively measure the quality of the fused images we have made the following controls: Firstly, we have examined the optical qualitative result. Then, we examined the correlation between the original multispectral and the fused images and all the statistical parameters of the histograms of the various frequency bands. All the fusion techniques improve the resolution and the optical result. In contrary to the fusion of other data (ETM, Spot5, Ikonos and Quickbird) all the algorithms provoke small changes to the statistical parameters.

  2. High-spatial-resolution nanoparticle x-ray fluorescence tomography

    NASA Astrophysics Data System (ADS)

    Larsson, Jakob C.; Vâgberg, William; Vogt, Carmen; Lundström, Ulf; Larsson, Daniel H.; Hertz, Hans M.

    2016-03-01

    X-ray fluorescence tomography (XFCT) has potential for high-resolution 3D molecular x-ray bio-imaging. In this technique the fluorescence signal from targeted nanoparticles (NPs) is measured, providing information about the spatial distribution and concentration of the NPs inside the object. However, present laboratory XFCT systems typically have limited spatial resolution (>1 mm) and suffer from long scan times and high radiation dose even at high NP concentrations, mainly due to low efficiency and poor signal-to-noise ratio. We have developed a laboratory XFCT system with high spatial resolution (sub-100 μm), low NP concentration and vastly decreased scan times and dose, opening up the possibilities for in-vivo small-animal imaging research. The system consists of a high-brightness liquid-metal-jet microfocus x-ray source, x-ray focusing optics and an energy-resolving photon-counting detector. By using the source's characteristic 24 keV line-emission together with carefully matched molybdenum nanoparticles the Compton background is greatly reduced, increasing the SNR. Each measurement provides information about the spatial distribution and concentration of the Mo nanoparticles. A filtered back-projection method is used to produce the final XFCT image.

  3. Spatial Classification of Orchards and Vineyards with High Spatial Resolution Panchromatic Imagery

    SciTech Connect

    Warner, Timothy; Steinmaus, Karen L.

    2005-02-01

    New high resolution single spectral band imagery offers the capability to conduct image classifications based on spatial patterns in imagery. A classification algorithm based on autocorrelation patterns was developed to automatically extract orchards and vineyards from satellite imagery. The algorithm was tested on IKONOS imagery over Granger, WA, which resulted in a classification accuracy of 95%.

  4. On the potential to enhance the spatial resolution of the day-night band (DNB) channel of the visible and infrared imaging radiometer suite (VIIRS) for the second joint polar satellite system (JPSS-2) and beyond

    NASA Astrophysics Data System (ADS)

    McCarthy, James K.; Jacobson, Eric J.; Kilduff, Timothy M.; Estes, Ronald W.; Levine, Peter A.; Mills, Steven D.; Elvidge, Chris; Miller, Steven D.

    2013-09-01

    This paper examines the feasibility and potential benefits of enhancing the spatial resolution of the VIIRS DNB channel for the JPSS-2 mission and beyond, by modifying the on-chip pixel binning recipe used in the DNB CCD to aggregate detector area within the scan swath. Presently the DNB delivers 16 cross-scan samples similar in size to the detectors in the VIIRS Moderate Resolution Bands. The relatively low-cost enhancement proposed would instead bin the pixels of the existing DNB CCD into 32 cross-scan samples, each half as large in track and scan, effectively doubling the spatial resolution of DNB in each dimension to match the VIIRS Imaging Bands at nadir. Other potential benefits include, for unresolved point sources, improved detection sensitivity and SNR. Smaller DNB image pixels would be less spatiallymixed, and therefore better suited to many quantitative analyses. DNB geolocation accuracy would also benefit from the increased spatial resolution, but less so for regions approaching edge-of-scan. To implement the maximum DNB spatial resolution enhancement over the full cross-track scan swath would require design and hardware modifications to the focal plane electronics (FPIE) to increase certain CCD clock rates. This paper explores the performance of this option, alongside other options that (if constrained to use the existing FPIE design with minimal changes) would not provide the enhanced DNB spatial resolution all the way out to the edges of the cross-track scan. These would instead offer other benefits, such as better maintaining SNR to edge-of-scan and, if away from nadir DNB sampling matched the I-bands, better enabling future environmental products merging the enhanced DNB data with existing VIIRS spectral band data.

  5. Nuclear magnetic resonance imaging at microscopic resolution

    NASA Astrophysics Data System (ADS)

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

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

  6. Evolution of spatial resolution in breast CT at UC Davis

    SciTech Connect

    Gazi, Peymon M.; Yang, Kai; Burkett, George W.; Aminololama-Shakeri, Shadi; Anthony Seibert, J.; Boone, John M.

    2015-04-15

    Purpose: Dedicated breast computed tomography (bCT) technology for the purpose of breast cancer screening has been a focus of research at UC Davis since the late 1990s. Previous studies have shown that improvement in spatial resolution characteristics of this modality correlates with greater microcalcification detection, a factor considered a potential limitation of bCT. The aim of this study is to improve spatial resolution as characterized by the modulation transfer function (MTF) via changes in the scanner hardware components and operational schema. Methods: Four prototypes of pendant-geometry, cone-beam breast CT scanners were designed and developed spanning three generations of design evolution. To improve the system MTF in each bCT generation, modifications were made to the imaging components (x-ray tube and flat-panel detector), system geometry (source-to-isocenter and detector distance), and image acquisition parameters (technique factors, number of projections, system synchronization scheme, and gantry rotational speed). Results: Characterization of different generations of bCT systems shows these modifications resulted in a 188% improvement of the limiting MTF properties from the first to second generation and an additional 110% from the second to third. The intrinsic resolution degradation in the azimuthal direction observed in the first generation was corrected by changing the acquisition from continuous to pulsed x-ray acquisition. Utilizing a high resolution detector in the third generation, along with modifications made in system geometry and scan protocol, resulted in a 125% improvement in limiting resolution. An additional 39% improvement was obtained by changing the detector binning mode from 2 × 2 to 1 × 1. Conclusions: These results underscore the advancement in spatial resolution characteristics of breast CT technology. The combined use of a pulsed x-ray system, higher resolution flat-panel detector and changing the scanner geometry and image

  7. Evolution of spatial resolution in breast CT at UC Davis

    PubMed Central

    Gazi, Peymon M.; Yang, Kai; Burkett, George W.; Aminololama-Shakeri, Shadi; Anthony Seibert, J.; Boone, John M.

    2015-01-01

    Purpose: Dedicated breast computed tomography (bCT) technology for the purpose of breast cancer screening has been a focus of research at UC Davis since the late 1990s. Previous studies have shown that improvement in spatial resolution characteristics of this modality correlates with greater microcalcification detection, a factor considered a potential limitation of bCT. The aim of this study is to improve spatial resolution as characterized by the modulation transfer function (MTF) via changes in the scanner hardware components and operational schema. Methods: Four prototypes of pendant-geometry, cone-beam breast CT scanners were designed and developed spanning three generations of design evolution. To improve the system MTF in each bCT generation, modifications were made to the imaging components (x-ray tube and flat-panel detector), system geometry (source-to-isocenter and detector distance), and image acquisition parameters (technique factors, number of projections, system synchronization scheme, and gantry rotational speed). Results: Characterization of different generations of bCT systems shows these modifications resulted in a 188% improvement of the limiting MTF properties from the first to second generation and an additional 110% from the second to third. The intrinsic resolution degradation in the azimuthal direction observed in the first generation was corrected by changing the acquisition from continuous to pulsed x-ray acquisition. Utilizing a high resolution detector in the third generation, along with modifications made in system geometry and scan protocol, resulted in a 125% improvement in limiting resolution. An additional 39% improvement was obtained by changing the detector binning mode from 2 × 2 to 1 × 1. Conclusions: These results underscore the advancement in spatial resolution characteristics of breast CT technology. The combined use of a pulsed x-ray system, higher resolution flat-panel detector and changing the scanner geometry and image

  8. Heuristic optimization in penumbral image for high resolution reconstructed image

    SciTech Connect

    Azuma, R.; Nozaki, S.; Fujioka, S.; Chen, Y. W.; Namihira, Y.

    2010-10-15

    Penumbral imaging is a technique which uses the fact that spatial information can be recovered from the shadow or penumbra that an unknown source casts through a simple large circular aperture. The size of the penumbral image on the detector can be mathematically determined as its aperture size, object size, and magnification. Conventional reconstruction methods are very sensitive to noise. On the other hand, the heuristic reconstruction method is very tolerant of noise. However, the aperture size influences the accuracy and resolution of the reconstructed image. In this article, we propose the optimization of the aperture size for the neutron penumbral imaging.

  9. Synchrotron Infrared Confocal Microspectroscopic Spatial Resolution or a Customized Synchrotron/focal Plane Array System Enhances Chemical Imaging of Biological Tissue or Cells

    SciTech Connect

    D Wetzel; M Nasse; =

    2011-12-31

    Spectroscopy and spatially resolved chemical imaging of biological materials using an infrared microscope is greatly enhanced with confocal image plane masking to 5-6 {mu} with a third generation microspectrometer and illumination with a synchrotron radiation source compared to globar illuminated and array detection or singly masked system. Steps toward this instrumental achievement are illustrated with spectra and images of biological tissue sections, including single cells, brain, aorta, and grain specimens. A recent, customized synchrotron infrared microspectrometer installation enables focal plane array detection to achieve both rapid and high definition chemical imaging. Localization of the ester carbonyl population in single modified starch granules was used to provide direct comparison of the two advanced imaging capabilities.

  10. Synchrotron infrared confocal microspectroscopic spatial resolution or a customized synchrotron/focal plane array system enhances chemical imaging of biological tissue or cells

    NASA Astrophysics Data System (ADS)

    Wetzel, David L.; Nasse, Michael J.

    2011-09-01

    Spectroscopy and spatially resolved chemical imaging of biological materials using an infrared microscope is greatly enhanced with confocal image plane masking to 5-6 μm with a third generation microspectrometer and illumination with a synchrotron radiation source compared to globar illuminated and array detection or singly masked system. Steps toward this instrumental achievement are illustrated with spectra and images of biological tissue sections, including single cells, brain, aorta, and grain specimens. A recent, customized synchrotron infrared microspectrometer installation enables focal plane array detection to achieve both rapid and high definition chemical imaging. Localization of the ester carbonyl population in single modified starch granules was used to provide direct comparison of the two advanced imaging capabilities.

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

    SciTech Connect

    Kotasidis, Fotis A.; Angelis, Georgios I.; Anton-Rodriguez, Jose; Matthews, Julian C.; Reader, Andrew J.; Zaidi, Habib

    2014-05-15

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

  12. HIGH SPATIAL RESOLUTION OBSERVATIONS OF LOOPS IN THE SOLAR CORONA

    SciTech Connect

    Brooks, David H.; Ugarte-Urra, Ignacio; Warren, Harry P.; Winebarger, Amy R.

    2013-08-01

    Understanding how the solar corona is structured is of fundamental importance to determine how the Sun's upper atmosphere is heated to high temperatures. Recent spectroscopic studies have suggested that an instrument with a spatial resolution of 200 km or better is necessary to resolve coronal loops. The High Resolution Coronal Imager (Hi-C) achieved this performance on a rocket flight in 2012 July. We use Hi-C data to measure the Gaussian widths of 91 loops observed in the solar corona and find a distribution that peaks at about 270 km. We also use Atmospheric Imaging Assembly data for a subset of these loops and find temperature distributions that are generally very narrow. These observations provide further evidence that loops in the solar corona are often structured at a scale of several hundred kilometers, well above the spatial scale of many proposed physical mechanisms.

  13. Potentiel des images satellitaires multibandes a haute resolution spatiale pour la cartographie des componsants de l'eau en milieu cotier marin

    NASA Astrophysics Data System (ADS)

    Lavoie, Andre

    organiques dissoutes. Particulierement dans la bande TM1, il est possible de definir trois classes de concentration dans l'intervalle de 0,5 a 12 g.m-3. Quant aux autres composants, un maximum de deux classes peut etre defini a la condition que la concentration en matieres minerales soit relativement faible. Une analyse du potentiel de suivi temporel de l'observation du milieu cotier marin a ete realisee. La compilation d'images archivees des capteurs TM et HRV montre qu'un utilisateur ne peut esperer obtenir plus de 2 a 3 bonnes images durant la periode estivale a nos latitudes (en combinant les deux capteurs). Finalement, les resultats obtenus montrent que le modele peut s'adapter a differents types d'eau et a differents capteurs parce que la formulation n'impose pas de rectrictions au niveau des caracteristiques des masses d'eau, de la resolution spatiale, spectrale et radiometrique du capteur simule. (Abstract shortened by UMI.)

  14. Spatial resolution and chest nodule detection: an interesting incidental finding

    NASA Astrophysics Data System (ADS)

    Toomey, R. J.; McEntee, M. F.; Ryan, J. T.; Evanoff, M. G.; Hayes, A.; Brennan, P. C.

    2010-02-01

    This study reports an incidental finding from a larger work. It examines the relationship between spatial resolution and nodule detection for chest radiographs. Twelve examining radiologists with the American Board of Radiology read thirty chest radiographs in two conditions - full (1500 × 1500 pixel) resolution, and 300 × 300 pixel resolution linearly interpolated to 1500 × 1500 pixels. All images were surrounded by a 10-pixel sharp grey border to aid in focussing the observer's eye when viewing the comparatively unsharp interpolated images. Fifteen of the images contained a single simulated pulmonary nodule. Observers were asked to rate their confidence that a nodule was present on each radiograph on a scale of 1 (least confidence, certain no lesion is present) to 6 (most confidence, certain a lesion was present). All other abnormalities were to be ignored. No windowing, levelling or magnification of the images was permitted and viewing distance was constrained to approximately 70cm. Images were displayed on a 3 megapixel greyscale monitor. Receiver operating characteristic (ROC) analysis was applied to the results of the readings using the Dorfman-Berbaum-Metz multiplereader, multiple-case method. No statistically significant differences were found with either readers and cases treated as random or with cases treated as fixed. Low spatial frequency information appears to be sufficient for the detection of chest lesion of the type used in this study.

  15. Spatial resolution in CBCT machines for dental/maxillofacial applications—what do we know today?

    PubMed Central

    Schulze, R K W

    2015-01-01

    Spatial resolution is one of the most important parameters objectively defining image quality, particularly in dental imaging, where fine details often have to be depicted. Here, we review the current status on assessment parameters for spatial resolution and on published data regarding spatial resolution in CBCT images. The current concepts of visual [line-pair (lp) measurements] and automated [modulation transfer function (MTF)] assessment of spatial resolution in CBCT images are summarized and reviewed. Published measurement data on spatial resolution in CBCT are evaluated and analysed. Effective (i.e. actual) spatial resolution available in CBCT images is being influenced by the two-dimensional detector, the three-dimensional reconstruction process, patient movement during the scan and various other parameters. In the literature, the values range between 0.6 and 2.8 lp mm−1 (visual assessment; median, 1.7 lp mm−1) vs MTF (range, 0.5–2.3 cycles per mm; median, 2.1 lp mm−1). Spatial resolution of CBCT images is approximately one order of magnitude lower than that of intraoral radiographs. Considering movement, scatter effects and other influences in real-world scans of living patients, a realistic spatial resolution of just above 1 lp mm−1 could be expected. PMID:25168812

  16. A multipinhole small animal SPECT system with submillimeter spatial resolution

    SciTech Connect

    Funk, Tobias; Despres, Philippe; Barber, William C.; Shah, Kanai S.; Hasegawa, Bruce H.

    2006-05-15

    Single photon emission computed tomography (SPECT) is an important technology for molecular imaging studies of small animals. In this arena, there is an increasing demand for high performance imaging systems that offer improved spatial resolution and detection efficiency. We have designed a multipinhole small animal imaging system based on position sensitive avalanche photodiode (PSAPD) detectors with the goal of submillimeter spatial resolution and high detection efficiency, which will allow us to minimize the radiation dose to the animal and to shorten the time needed for the imaging study. Our design will use 8x24 mm{sup 2} PSAPD detector modules coupled to thallium-doped cesium iodide [CsI(Tl)] scintillators, which can achieve an intrinsic spatial resolution of 0.5 mm at 140 keV. These detectors will be arranged in rings of 24 modules each; the animal is positioned in the center of the 9 stationary detector rings which capture projection data from the animal with a cylindrical tungsten multipinhole collimator. The animal is supported on a bed which can be rocked about the central axis to increase angular sampling of the object. In contrast to conventional SPECT pinhole systems, in our design each pinhole views only a portion of the object. However, the ensemble of projection data from all of the multipinhole detectors provide angular sampling that is sufficient to reconstruct tomographic data from the object. The performance of this multipinhole PSAPD imaging system was simulated using a ray tracing program that models the appropriate point spread functions and then was compared against the performance of a dual-headed pinhole SPECT system. The detection efficiency of both systems was simulated and projection data of a hot rod phantom were generated and reconstructed to assess spatial resolution. Appropriate Poisson noise was added to the data to simulate an acquisition time of 15 min and an activity of 18.5 MBq distributed in the phantom. Both sets of data

  17. A super resolution framework for low resolution document image OCR

    NASA Astrophysics Data System (ADS)

    Ma, Di; Agam, Gady

    2013-01-01

    Optical character recognition is widely used for converting document images into digital media. Existing OCR algorithms and tools produce good results from high resolution, good quality, document images. In this paper, we propose a machine learning based super resolution framework for low resolution document image OCR. Two main techniques are used in our proposed approach: a document page segmentation algorithm and a modified K-means clustering algorithm. Using this approach, by exploiting coherence in the document, we reconstruct from a low resolution document image a better resolution image and improve OCR results. Experimental results show substantial gain in low resolution documents such as the ones captured from video.

  18. High resolution ultraviolet imaging spectrometer for latent image analysis.

    PubMed

    Lyu, Hang; Liao, Ningfang; Li, Hongsong; Wu, Wenmin

    2016-03-21

    In this work, we present a close-range ultraviolet imaging spectrometer with high spatial resolution, and reasonably high spectral resolution. As the transmissive optical components cause chromatic aberration in the ultraviolet (UV) spectral range, an all-reflective imaging scheme is introduced to promote the image quality. The proposed instrument consists of an oscillating mirror, a Cassegrain objective, a Michelson structure, an Offner relay, and a UV enhanced CCD. The finished spectrometer has a spatial resolution of 29.30μm on the target plane; the spectral scope covers both near and middle UV band; and can obtain approximately 100 wavelength samples over the range of 240~370nm. The control computer coordinates all the components of the instrument and enables capturing a series of images, which can be reconstructed into an interferogram datacube. The datacube can be converted into a spectrum datacube, which contains spectral information of each pixel with many wavelength samples. A spectral calibration is carried out by using a high pressure mercury discharge lamp. A test run demonstrated that this interferometric configuration can obtain high resolution spectrum datacube. The pattern recognition algorithm is introduced to analyze the datacube and distinguish the latent traces from the base materials. This design is particularly good at identifying the latent traces in the application field of forensic imaging. PMID:27136837

  19. Quantifying mangrove chlorophyll from high spatial resolution imagery

    NASA Astrophysics Data System (ADS)

    Heenkenda, Muditha K.; Joyce, Karen E.; Maier, Stefan W.; de Bruin, Sytze

    2015-10-01

    Lower than expected chlorophyll concentration of a plant can directly limit photosynthetic activity, and resultant primary production. Low chlorophyll concentration may also indicate plant physiological stress. Compared to other terrestrial vegetation, mangrove chlorophyll variations are poorly understood. This study quantifies the spatial distribution of mangrove canopy chlorophyll variation using remotely sensed data and field samples over the Rapid Creek mangrove forest in Darwin, Australia. Mangrove leaf samples were collected and analyzed for chlorophyll content in the laboratory. Once the leaf area index (LAI) of sampled trees was estimated using the digital cover photography method, the canopy chlorophyll contents were calculated. Then, the nonlinear random forests regression algorithm was used to describe the relationship between canopy chlorophyll content and remotely sensed data (WorldView-2 satellite image bands and their spectral transformations), and to estimate the spatial distribution of canopy chlorophyll variation. The imagery was evaluated at full 2 m spatial resolution, as well as at decreased resampled resolutions of 5 m and 10 m. The root mean squared errors with validation samples were 0.82, 0.64 and 0.65 g/m2 for maps at 2 m, 5 m and 10 m spatial resolution respectively. The correlation coefficient was analyzed for the relationship between measured and predicted chlorophyll values. The highest correlation: 0.71 was observed at 5 m spatial resolution (R2 = 0.5). We therefore concluded that estimating mangrove chlorophyll content from remotely sensed data is possible using red, red-edge, NIR1 and NIR2 bands and their spectral transformations as predictors at 5 m spatial resolution.

  20. Final Technical Report for DE-FG02-06ER15835: Chemical Imaging with 100nm Spatial Resolution: Combining High Resolution Flurosecence Microscopy and Ion Mobility Mass Spectrometry

    SciTech Connect

    Buratto, Steven K.

    2013-09-03

    We have combined, in a single instrument, high spatial resolution optical microscopy with the chemical specificity and conformational selectivity of ion mobility mass spectrometry. We discuss the design and construction of this apparatus as well as our efforts in applying this technique to thin films of molecular semiconductor materials.

  1. Relating Spatial Patterns in Image Data to Scene Characteristics

    NASA Technical Reports Server (NTRS)

    Strahler, A. H.; Woodcock, C. E.

    1983-01-01

    In remote sensing, the primary goal is accurate scene inference, in which characteristics of the scene are inferred from the image data. More effective inference of scene characteristics can be accomplished through the use of techniques that use explicit models of spatial pattern. Spatial patterns in image data are functionally related to the size and spacing of elements in the scene and to the spatial resolution of the image data. At resolutions where variance is high, scene inference techniques should rely heavily on data from the spatial domain. As variance decreases, effective scene inference will increasingly rely on spectral data.

  2. Spatial Autocorrelation in Mass Spectrometry Imaging.

    PubMed

    Cassese, Alberto; Ellis, Shane R; Ogrinc Potočnik, Nina; Burgermeister, Elke; Ebert, Matthias; Walch, Axel; van den Maagdenberg, Arn M J M; McDonnell, Liam A; Heeren, Ron M A; Balluff, Benjamin

    2016-06-01

    Mass spectrometry imaging (MSI) is a powerful molecular imaging technique. In microprobe MSI, images are created through a grid-wise interrogation of individual spots by mass spectrometry across a surface. Classical statistical tests for within-sample comparisons fail as close-by measurement spots violate the assumption of independence of these tests, which can lead to an increased false-discovery rate. For spatial data, this effect is referred to as spatial autocorrelation. In this study, we investigated spatial autocorrelation in three different matrix-assisted laser desorption/ionization MSI data sets. These data sets cover different molecular classes (metabolites/drugs, lipids, and proteins) and different spatial resolutions ranging from 20 to 100 μm. Significant spatial autocorrelation was detected in all three data sets and found to increase with decreasing pixel size. To enable statistical testing for differences in mass signal intensities between regions of interest within MSI data sets, we propose the use of Conditional Autoregressive (CAR) models. We show that, by accounting for spatial autocorrelation, discovery rates (i.e., the ratio between the features identified and the total number of features) could be reduced between 21% and 69%. The reliability of this approach was validated by control mass signals based on prior knowledge. In light of the advent of larger MSI data sets based on either an increased spatial resolution or 3D data sets, accounting for effects due to spatial autocorrelation becomes even more indispensable. Here, we propose a generic and easily applicable workflow to enable within-sample statistical comparisons. PMID:27180608

  3. A high-spatial-resolution fiber-optic-coupled CMOS imager with novel scintillator for high-energy x-ray applications

    NASA Astrophysics Data System (ADS)

    Baur, Robin M.; Tate, Mark W.; Dale, Darren S.; Gruner, Sol M.

    2013-03-01

    A fast, high-spatial-resolution detector for high-energy microscopy work is presented. The detector uses a 2160 × 2560 CMOS chip for fast framing (up to 100 Hz in full-frame mode), coupled by a fiber optic taper to a scintillating Terbium-doped fiber optic plate for excellent stopping power even at high energies. The field of view is 7mm × 8.6mm with a resolution of 9 microns. The sensitivity is 1 e-/x-ray at 35 keV, with a read noise of 2.5 e-/pixel. Standard characterization metrics including dark current, sensitivity, modulation transfer function, and detective quantum efficiency are presented, along with preliminary experimental results.

  4. Camera system resolution and its influence on digital image correlation

    SciTech Connect

    Reu, Phillip L.; Sweatt, William; Miller, Timothy; Fleming, Darryn

    2014-09-21

    Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss of spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.

  5. Camera system resolution and its influence on digital image correlation

    DOE PAGESBeta

    Reu, Phillip L.; Sweatt, William; Miller, Timothy; Fleming, Darryn

    2014-09-21

    Digital image correlation (DIC) uses images from a camera and lens system to make quantitative measurements of the shape, displacement, and strain of test objects. This increasingly popular method has had little research on the influence of the imaging system resolution on the DIC results. This paper investigates the entire imaging system and studies how both the camera and lens resolution influence the DIC results as a function of the system Modulation Transfer Function (MTF). It will show that when making spatial resolution decisions (including speckle size) the resolution limiting component should be considered. A consequence of the loss ofmore » spatial resolution is that the DIC uncertainties will be increased. This is demonstrated using both synthetic and experimental images with varying resolution. The loss of image resolution and DIC accuracy can be compensated for by increasing the subset size, or better, by increasing the speckle size. The speckle-size and spatial resolution are now a function of the lens resolution rather than the more typical assumption of the pixel size. The study will demonstrate the tradeoffs associated with limited lens resolution.« less

  6. Radiometric and Spatial Characterization of High-Spatial Resolution Sensors

    NASA Technical Reports Server (NTRS)

    Thome, Kurtis; Zanoni, Vicki (Technical Monitor)

    2002-01-01

    The development and improvement of commercial hyperspatial sensors in recent years has increased the breadth of information that can be retrieved from spaceborne and airborne imagery. NASA, through it's Scientific Data Purchases, has successfully provided such data sets to its user community. A key element to the usefulness of these data are an understanding of the radiometric and spatial response quality of the imagery. This proposal seeks funding to examine the absolute radiometric calibration of the Ikonos sensor operated by Space Imaging and the recently-launched Quickbird sensor from DigitalGlobe. In addition, we propose to evaluate the spatial response of the two sensors. The proposed methods rely on well-understood, ground-based targets that have been used by the University of Arizona for more than a decade.

  7. Highest Resolution Image of Europa

    NASA Technical Reports Server (NTRS)

    1998-01-01

    During its twelfth orbit around Jupiter, on Dec. 16, 1997, NASA's Galileo spacecraft made its closest pass of Jupiter's icy moon Europa, soaring 200 kilometers (124 miles) kilometers above the icy surface. This image was taken near the closest approach point, at a range of 560 kilometers (335 miles) and is the highest resolution picture of Europa that will be obtained by Galileo. The image was taken at a highly oblique angle, providing a vantage point similar to that of someone looking out an airplane window. The features at the bottom of the image are much closer to the viewer than those at the top of the image. Many bright ridges are seen in the picture, with dark material in the low-lying valleys. In the center of the image, the regular ridges and valleys give way to a darker region of jumbled hills, which may be one of the many dark pits observed on the surface of Europa. Smaller dark, circular features seen here are probably impact craters.

    North is to the right of the picture, and the sun illuminates the surface from that direction. This image, centered at approximately 13 degrees south latitude and 235 degrees west longitude, is approximately 1.8 kilometers (1 mile) wide. The resolution is 6 meters (19 feet) per picture element. This image was taken on December 16, 1997 by the solid state imaging system camera on NASA's Galileo spacecraft.

    The Jet Propulsion Laboratory, Pasadena, CA manages the Galileo mission for NASA's Office of Space Science, Washington, DC. JPL is an operating division of California Institute of Technology (Caltech).

    This image and other images and data received from Galileo are posted on the World Wide Web, on the Galileo mission home page at URL http://www.jpl.nasa.gov/ galileo.

  8. High spatial resolution imaging of SO and H2CO in AB Auriga: The first SO image in a transitional disk⭑

    PubMed Central

    Pacheco-Vázquez, S; Fuente, A; Baruteau, C; Berné, O; Agúndez, M; Neri, R; Goicoechea, JR; Cernicharo, J; Bachiller, R

    2016-01-01

    Context Transitional disks are structures of dust and gas around young stars with large inner cavities in which planet formation may occur. Lopsided dust distributions are observed in the dust continuum emission at millimeter wavelengths. These asymmetrical structures can be explained as being the result of an enhanced gas density vortex where the dust is trapped, potentially promoting the rapid growth to the planetesimal scale. Aims AB Aur hosts a transitional disk with a clear horseshoe morphology which strongly suggests the presence of a dust trap. Our goal is to investigate its formation and the possible effects on the gas chemistry. Methods We used the NOEMA (NOrthern Extended Millimeter Array) interferometer to image the 1mm continuum dust emission and the 13CO J=2 →1, C18OJ=2 →1, SO J=56 →45, and H2CO J=303 →202 rotational lines. Results Line integrated intensity ratio images are built to investigate the chemical changes within the disk. The I(H2CO J=303 →202)/I(C18O J=2→1) ratio is fairly constant along the disk with values of ~0.15±0.05. On the contrary, the I(SO J=56 →45)/I(C18O J=2 →1) and I(SO J=56 →45)/I(H2CO J=303 →202) ratios present a clear northeast-southwest gradient (a factor of 3–6) with the minimum towards the dust trap. This gradient cannot be explained by a local change in the excitation conditions but by a decrease in the SO abundance. Gas densities up to ~109 cm−3 are expected in the disk midplane and two-three times larger in the high pressure vortex. We have used a single point (n,T) chemical model to investigate the lifetime of gaseous CO, H2CO, and SO in the dust trap. Our model shows that for densities >107 cm−3, the SO molecules are depleted (directly frozen, or converted into SO2 and then frozen out) in less than 0.1 Myr. The lower SO abundance towards the dust trap could indicate that a larger fraction of the gas is in a high density environment. Conclusions Gas dynamics, grain growth and gas chemistry are

  9. High spatial resolution imaging of SO and H2CO in AB Auriga: The first SO image in a transitional disk

    NASA Astrophysics Data System (ADS)

    Pacheco-Vázquez, S.; Fuente, A.; Baruteau, C.; Berné, O.; Agúndez, M.; Neri, R.; Goicoechea, J. R.; Cernicharo, J.; Bachiller, R.

    2016-05-01

    Context. Transitional disks are structures of dust and gas around young stars with large inner cavities in which planet formation may occur. Lopsided dust distributions are observed in the dust continuum emission at millimeter wavelengths. These asymmetrical structures can be explained as being the result of an enhanced gas density vortex where the dust is trapped, potentially promoting the rapid growth to the planetesimal scale. Aims: AB Aur hosts a transitional disk with a clear horseshoe morphology which strongly suggests the presence of a dust trap. Our goal is to investigate its formation and the possible effects on the gas chemistry. Methods: We used the NOrthern Extended Millimeter Array (NOEMA) interferometer to image the 1 mm continuum dust emission and the 13CO J = 2 → 1, C18O J = 2 → 1, SO J = 56 → 45, and H2CO J = 303 → 202 rotational lines. Results: Line integrated intensity ratio images are built to investigate the chemical changes within the disk. The I(H2CO J = 303 → 202)/I(C18O J = 2 → 1) ratio is fairly constant along the disk with values of ~0.15 ± 0.05. On the contrary, the I(SO J = 56 → 45)/I(C18O J = 2 → 1) and I(SO J = 56 → 45)/I(H2CO J = 303 → 202) ratios present a clear northeast-southwest gradient (a factor of 3-6) with the minimum towards the dust trap. This gradient cannot be explained by a local change in the excitation conditions but by a decrease in the SO abundance. Gas densities up to ~109 cm-3 are expected in the disk midplane and two-three times larger in the high pressure vortex. We have used a single point (n,T) chemical model to investigate the lifetime of gaseous CO, H2CO, and SO in the dust trap. Our model shows that for densities >107 cm-3, the SO molecules are depleted (directly frozen, or converted into SO2 and then frozen out) in less than 0.1 Myr. The lower SO abundance towards the dust trap could indicate that a larger fraction of the gas is in a high density environment. Conclusions: Gas dynamics

  10. Spatial resolution of a hard x-ray CCD detector

    SciTech Connect

    Seely, John F.; Pereira, Nino R.; Weber, Bruce V.; Schumer, Joseph W.; Apruzese, John P.; Hudson, Lawrence T.; Szabo, Csilla I.; Boyer, Craig N.; Skirlo, Scott

    2010-08-10

    The spatial resolution of an x-ray CCD detector was determined from the widths of the tungsten x-ray lines in the spectrum formed by a crystal spectrometer in the 58 to 70 keV energy range. The detector had 20{mu}m pixel, 1700 by 1200 pixel format, and a CsI x-ray conversion scintillator. The spectral lines from a megavolt x-ray generator were focused on the spectrometer's Rowland circle by a curved transmission crystal. The line shapes were Lorentzian with an average width after removal of the natural and instrumental line widths of 95{mu}m (4.75 pixels). A high spatial frequency background, primarily resulting from scattered gamma rays, was removed from the spectral image by Fourier analysis. The spectral lines, having low spatial frequency in the direction perpendicular to the dispersion, were enhanced by partially removing the Lorentzian line shape and by fitting Lorentzian curves to broad unresolved spectral features. This demonstrates the ability to improve the spectral resolution of hard x-ray spectra that are recorded by a CCD detector with well-characterized intrinsic spatial resolution.

  11. High-Resolution Imaging Spectrometer

    NASA Technical Reports Server (NTRS)

    Dozier, Jeff; Goetz, Alexander F. H.

    1990-01-01

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

  12. Super-resolution imaging system

    NASA Technical Reports Server (NTRS)

    Jain, Atul (Inventor)

    1979-01-01

    The resolution of an imaging system is greatly enhanced by radiating an object with a plane wave field from a coherent source variable in either frequency, angle or distance from the object, detecting the wave field transmitted through, or reflected from, the object at some point on the image of the object, with or without heterodyne detection, and with or without a lens system. The heterodyne detected output of the detector is processed to obtain the Fourier transform as a function of the variable for a direct measurement of the amplitude and surface height structure of the object within a resolution cell centered at the corresponding point on the object. In the case of no heterodyne detection, only intensity data is obtained for a Fourier spectrum.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  14. Science with High Spatial Resolution Far-Infrared Data

    NASA Technical Reports Server (NTRS)

    Terebey, Susan (Editor); Mazzarella, Joseph M. (Editor)

    1994-01-01

    The goal of this workshop was to discuss new science and techniques relevant to high spatial resolution processing of far-infrared data, with particular focus on high resolution processing of IRAS data. Users of the maximum correlation method, maximum entropy, and other resolution enhancement algorithms applicable to far-infrared data gathered at the Infrared Processing and Analysis Center (IPAC) for two days in June 1993 to compare techniques and discuss new results. During a special session on the third day, interested astronomers were introduced to IRAS HIRES processing, which is IPAC's implementation of the maximum correlation method to the IRAS data. Topics discussed during the workshop included: (1) image reconstruction; (2) random noise; (3) imagery; (4) interacting galaxies; (5) spiral galaxies; (6) galactic dust and elliptical galaxies; (7) star formation in Seyfert galaxies; (8) wavelet analysis; and (9) supernova remnants.

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

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

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

  16. Spatial resolution effect of light coupling structures

    NASA Astrophysics Data System (ADS)

    Li, Juntao; Li, Kezheng; Schuster, Christian; Su, Rongbin; Wang, Xuehua; Borges, Ben-Hur V.; Krauss, Thomas F.; Martins, Emiliano R.

    2015-12-01

    The coupling of light between free space and thin film semiconductors is an essential requirement of modern optoelectronic technology. For monochromatic and single mode devices, high performance grating couplers have been developed that are well understood. For broadband and multimode devices, however, more complex structures, here referred to as “coupling surfaces”, are required, which are often difficult to realise technologically. We identify general design rules based on the Fourier properties of the coupling surface and show how they can be used to determine the spatial resolution required for the coupler’s fabrication. To our knowledge, this question has not been previously addressed, but it is important for the understanding of diffractive nanostructures and their technological realisation. We exemplify our insights with solar cells and UV photodetectors, where high-performance nanostructures that can be realised cost-effectively are essential.

  17. Spatial resolution effect of light coupling structures

    PubMed Central

    Li, Juntao; Li, Kezheng; Schuster, Christian; Su, Rongbin; Wang, Xuehua; Borges, Ben-Hur V.; Krauss, Thomas F.; Martins, Emiliano R.

    2015-01-01

    The coupling of light between free space and thin film semiconductors is an essential requirement of modern optoelectronic technology. For monochromatic and single mode devices, high performance grating couplers have been developed that are well understood. For broadband and multimode devices, however, more complex structures, here referred to as “coupling surfaces”, are required, which are often difficult to realise technologically. We identify general design rules based on the Fourier properties of the coupling surface and show how they can be used to determine the spatial resolution required for the coupler’s fabrication. To our knowledge, this question has not been previously addressed, but it is important for the understanding of diffractive nanostructures and their technological realisation. We exemplify our insights with solar cells and UV photodetectors, where high-performance nanostructures that can be realised cost-effectively are essential. PMID:26678574

  18. High Spatial Resolution Spectroscopy of Semiconductor Nanostructures

    NASA Astrophysics Data System (ADS)

    Harris, Timothy D.; Gershoni, David; Pfeiffer, Loren N.

    1996-03-01

    Several recent reports employing high spatial resolution have revealed the dominance of exciton localization in the low temperature luminescence of semiconductor quantum structures.^[1-3] Understanding this localization is of critical importance for the reliable studies of low dimensional structures such as quantum wells, quantum wires and quantum dots. We report on low temperature and high spatial resolution photoluminescence and photoluminescence excitation studies of cleaved edge overgrown (CEO) single quantum wires. These samples permit the direct and unambiguous comparison between the optical properties of a (100) oriented quantum well, a (110) oriented quantum well, and the quantum wire which is formed at their intersection. Using low temperature near field optical spectroscopy, and a novel diffraction limited far field apparatus, we determine the carrier diffusion length dependence on pump wavelength and sample temperature in both the 2d systems and the genuinely 1D wire system. We also measure the absorption strength of the 1D system and find it to be a factor of 3 stronger than the absorption of the associated 2D systems.^[2] Using low temperature near field optical spectroscopy, and a novel diffraction limited far field apparatus, we also determine the carrier diffusion length dependence on pump wavelength and sample temperature. ^[1] H. F. Hess, E. Betzig, T. D. Harris, L. N. Pfeiffer, and K. W. West, Science 264, 1740 (1994). ^[2] T. D. Harris, D. Gershoni, R. D. Grober, L. Pfeiffer, K. West, and N. Chand, Appl. Phys. Lett, in press (1996) ^[3] D. Gammon, E. S. Snow, and D. S. Katzer, Appl. Phys. Lett. 67, 2391 (1995)

  19. Comparison of performance of object-based image analysis techniques available in open source software (Spring and Orfeo Toolbox/Monteverdi) considering very high spatial resolution data

    NASA Astrophysics Data System (ADS)

    Teodoro, Ana C.; Araujo, Ricardo

    2016-01-01

    The use of unmanned aerial vehicles (UAVs) for remote sensing applications is becoming more frequent. However, this type of information can result in several software problems related to the huge amount of data available. Object-based image analysis (OBIA) has proven to be superior to pixel-based analysis for very high-resolution images. The main objective of this work was to explore the potentialities of the OBIA methods available in two different open source software applications, Spring and OTB/Monteverdi, in order to generate an urban land cover map. An orthomosaic derived from UAVs was considered, 10 different regions of interest were selected, and two different approaches were followed. The first one (Spring) uses the region growing segmentation algorithm followed by the Bhattacharya classifier. The second approach (OTB/Monteverdi) uses the mean shift segmentation algorithm followed by the support vector machine (SVM) classifier. Two strategies were followed: four classes were considered using Spring and thereafter seven classes were considered for OTB/Monteverdi. The SVM classifier produces slightly better results and presents a shorter processing time. However, the poor spectral resolution of the data (only RGB bands) is an important factor that limits the performance of the classifiers applied.

  20. Increasing FTIR spectromicroscopy speed and resolution through compressive imaging

    SciTech Connect

    Gallet, Julien; Riley, Michael; Hao, Zhao; Martin, Michael C

    2007-10-15

    At the Advanced Light Source at Lawrence Berkeley National Laboratory, we are investigating how to increase both the speed and resolution of synchrotron infrared imaging. Synchrotron infrared beamlines have diffraction-limited spot sizes and high signal to noise, however spectral images must be obtained one point at a time and the spatial resolution is limited by the effects of diffraction. One technique to assist in speeding up spectral image acquisition is described here and uses compressive imaging algorithms. Compressive imaging can potentially attain resolutions higher than allowed by diffraction and/or can acquire spectral images without having to measure every spatial point individually thus increasing the speed of such maps. Here we present and discuss initial tests of compressive imaging techniques performed with ALS Beamline 1.4.3?s Nic-Plan infrared microscope, Beamline 1.4.4 Continuum XL IR microscope, and also with a stand-alone Nicolet Nexus 470 FTIR spectrometer.

  1. High-resolution ophthalmic imaging system

    DOEpatents

    Olivier, Scot S.; Carrano, Carmen J.

    2007-12-04

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

  2. Temporal resolution in fluorescence imaging

    PubMed Central

    Mondal, Partha Pratim

    2014-01-01

    Temporal resolution is a key factor for imaging rapidly occurring events in biology. In this feature article, I investigate an approximate estimate for determining the temporal resolution limit. The condition that led to this limit is, the time taken by the ensemble (99.9%) of excited molecules to relax to ground state, assuming all the emitted photons are detected. In a simplistic three-level system, the temporal resolution is, ≈3τp, where τp = (loge10)/(kf + knr) and, kf and knr are respectively the radiative and non-radiative emission rates. This further assumes the ideal condition that, the quantum efficiency of the detector is unity and there are no other loses. We discuss few state-of-art microscopy techniques that are capable of high temporal resolution. This includes techniques such as multifocal multiphoton microscopy (MMM), multifocal plane microscopy, multiple excitation spot optical microscopy (MESO), multiplane microscopy and multiple light-sheet microscopy (MLSM). PMID:25988152

  3. Selecting the spatial resolution of satellite sensors required for global monitoring of land transformations

    NASA Technical Reports Server (NTRS)

    Townshend, J. R. G.; Justice, C. O.

    1988-01-01

    The paper provides preliminary evidence for the spatial resolutions required to monitor land transformations at broad scales. This is obtained from simulations of imagery at various spatial resolutions between 125 and 4000 m derived from Landsat MSS imagery. Consideration is given to the various types of spatial images detectable by remotely-sensed systems, as well as to the difficulties associated in disentangling permanent land transformations from shorter term changes such as phenological and interannual changes.

  4. Spatial and temporal resolution of fluid flows: LDRD final report

    SciTech Connect

    Tieszen, S.R.; O`Hern, T.J.; Schefer, R.W.; Perea, L.D.

    1998-02-01

    This report describes a Laboratory Directed Research and Development (LDRD) activity to develop a diagnostic technique for simultaneous temporal and spatial resolution of fluid flows. The goal is to obtain two orders of magnitude resolution in two spatial dimensions and time simultaneously. The approach used in this study is to scale up Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF) to acquire meter-size images at up to 200 frames/sec. Experiments were conducted in buoyant, fully turbulent, non-reacting and reacting plumes with a base diameter of one meter. The PIV results were successful in the ambient gas for all flows, and in the plume for non-reacting helium and reacting methane, but not reacting hydrogen. No PIV was obtained in the hot combustion product region as the seed particles chosen vaporized. Weak signals prevented PLIF in the helium. However, in reacting methane flows, PLIF images speculated to be from Poly-Aromatic-Hydrocarbons were obtained which mark the flame sheets. The results were unexpected and very insightful. A natural fluorescence from the seed particle vapor was also noted in the hydrogen tests.

  5. Proceedings of the 2004 High Spatial Resolution Commercial Imagery Workshop

    NASA Technical Reports Server (NTRS)

    2006-01-01

    Topics covered include: NASA Applied Sciences Program; USGS Land Remote Sensing: Overview; QuickBird System Status and Product Overview; ORBIMAGE Overview; IKONOS 2004 Calibration and Validation Status; OrbView-3 Spatial Characterization; On-Orbit Modulation Transfer Function (MTF) Measurement of QuickBird; Spatial Resolution Characterization for QuickBird Image Products 2003-2004 Season; Image Quality Evaluation of QuickBird Super Resolution and Revisit of IKONOS: Civil and Commercial Application Project (CCAP); On-Orbit System MTF Measurement; QuickBird Post Launch Geopositional Characterization Update; OrbView-3 Geometric Calibration and Geopositional Accuracy; Geopositional Statistical Methods; QuickBird and OrbView-3 Geopositional Accuracy Assessment; Initial On-Orbit Spatial Resolution Characterization of OrbView-3 Panchromatic Images; Laboratory Measurement of Bidirectional Reflectance of Radiometric Tarps; Stennis Space Center Verification and Validation Capabilities; Joint Agency Commercial Imagery Evaluation (JACIE) Team; Adjacency Effects in High Resolution Imagery; Effect of Pulse Width vs. GSD on MTF Estimation; Camera and Sensor Calibration at the USGS; QuickBird Geometric Verification; Comparison of MODTRAN to Heritage-based Results in Vicarious Calibration at University of Arizona; Using Remotely Sensed Imagery to Determine Impervious Surface in Sioux Falls, South Dakota; Estimating Sub-Pixel Proportions of Sagebrush with a Regression Tree; How Do YOU Use the National Land Cover Dataset?; The National Map Hazards Data Distribution System; Recording a Troubled World; What Does This-Have to Do with This?; When Can a Picture Save a Thousand Homes?; InSAR Studies of Alaska Volcanoes; Earth Observing-1 (EO-1) Data Products; Improving Access to the USGS Aerial Film Collections: High Resolution Scanners; Improving Access to the USGS Aerial Film Collections: Phoenix Digitizing System Product Distribution; System and Product Characterization: Issues Approach

  6. High-resolution time and spatial imaging of tobacco and its pyrolysis products during a cigarette puff by microprobe sampling photoionisation mass spectrometry.

    PubMed

    Hertz-Schünemann, R; Ehlert, S; Streibel, T; Liu, C; McAdam, K; Baker, R R; Zimmermann, R

    2015-03-01

    The time- and space-resolved chemical signatures of gases and vapours formed in solid-state combustion processes are difficult to examine using recent analytical techniques. A machine-smoked cigarette represents a very reproducible model system for dynamic solid-state combustion. By using a special sampling system (microprobe unit) that extracts the formed gases from inside of the burning cigarette, which is coupled to a photoionisation mass spectrometer, it was possible to study the evolution of organic gases during a 2-s cigarette puff. The concentrations of various pyrolysis and combustion products such as 1,3-butadiene, toluene, acetaldehyde and phenol were monitored on-line at different sampling points within cigarettes. A near-microscopic-scale spatial resolution and a 200-ms time resolution were achieved. Finally, the recorded information was combined to generate time-resolved concentration maps, showing the formation and destruction zones of the investigated compounds in the burning cigarette. The combustion zone at the tip of cigarette, where e.g. 1,3-butadiene is predominately formed, was clearly separable from the pyrolysis zones. Depending on the stability of the precursor (e.g. lignin or cellulose), the position of pyrolytic formation varies. In conclusion, it was demonstrated that soft photoionisation mass spectrometry in conjunction with a microprobe sampling device can be used for time- and space-resolved analysis of combustion and pyrolysis reactions. In addition to studies on the model cigarette, further model systems may be studied with this approach. This may include further studies on the combustion of biomass or coal chunks, on heterogeneously catalysed reactions or on spray, dust and gas combustion processes. PMID:25627787

  7. Enhanced spatial resolution on figures versus grounds.

    PubMed

    Hecht, Lauren N; Cosman, Joshua D; Vecera, Shaun P

    2016-07-01

    Much is known about the cues that determine figure-ground assignment, but less is known about the consequences of figure-ground assignment on later visual processing. Previous work has demonstrated that regions assigned figural status are subjectively more shape-like and salient than background regions. The increase in subjective salience of figural regions could be caused by a number of processes, one of which may be enhanced perceptual processing (e.g., an enhanced neural representation) of figures relative to grounds. We explored this hypothesis by having observers perform a perceptually demanding spatial resolution task in which targets appeared on either figure or ground regions. To rule out a purely attentional account of figural salience, observers discriminated targets on the basis of a region's color (red or green), which was equally likely to define the figure or the ground. The results of our experiments showed that targets appearing on figures were discriminated more accurately than those appearing in ground regions. In addition, targets appearing on figures were discriminated better than those presented in regions considered figurally neutral, but targets appearing within ground regions were discriminated more poorly than those appearing in figurally neutral regions. Taken together, our findings suggest that when two regions share a contour, regions assigned as figure are perceptually enhanced, whereas regions assigned as ground are perceptually suppressed. PMID:27048441

  8. Spatial resolution effects on the assessment of evapotranspiration in olive orchards using high resolution thermal imagery

    NASA Astrophysics Data System (ADS)

    Santos, Cristina; Zarco-Tejada, Pablo J.; Lorite, Ignacio J.; Allen, Richard G.

    2013-04-01

    The use of remote sensing techniques for estimating surface energy balance and water consumption has significantly improved the characterization of the agricultural systems by determining accurate information about crop evapotranspiration and stress, mainly for extensive crops. However the use of these methodologies for woody crops has been low due to the difficulty in the accurate characterization of these crops, mainly caused by a coarse resolution of the imagery provided by the most widely used satellites (such as Landsat 5 and 7). The coarse spatial resolution provided by these satellite sensors aggregates into a single pixel the tree crown, sunlit and shaded soil components. These surfaces can each exhibit huge differences in temperature, albedo and vegetation indexes calculated in the visible, near infrared and short-wave infrared regions. Recent studies have found that the use of energy balance approaches can provide useful results for non-homogeneous crops (Santos et al., 2012) but detailed analysis is required to determine the effect of the spatial resolution and the aggregation of the scene components in these heterogeneous canopies. In this study a comparison between different spatial resolutions has been conducted using images from Landsat 7 (with thermal resolution of 60m) and from an airborne thermal (with resolution of 80 cm) flown over olive orchards at different dates coincident with the Landsat overpass. The high resolution thermal imagery was resampled at different scales to generate images with spatial resolution ranging from 0.8 m up to 120m (thermal resolution for Landsat 5 images). The selection of the study area was made to avoid those areas with missing Landsat 7 data caused by SLC-off gaps. The selected area has a total area of around 2500 ha and is located in Southern Spain, in the province of Malaga. The selected area is mainly cultivated with olive orchards with different crop practices (rainfed, irrigated, high density, young and adult

  9. Spatial resolution of gated x-ray pinhole cameras

    SciTech Connect

    Robey, H.F.; Budil, K.S.; Remington, B.A.

    1996-05-15

    The new camera FXI was investigated. Spatial resolution, or its Fourier transform, the modulation transfer function (MTF), is critical for quantitative interpretation of recent hydrodynamic instability data taken on the Nova laser. We have taken data corresponding to backlit straight edges, pinholes, and grids, both on the bench and {ital in}{ital situ} on Nova. For both the pinhole and edge data, the MTF at all wavelengths of interest can be deduced from a single image. Grids are of more limited usefulness, giving the MTF value only at the spatial period of the grid. These different techniques for characterizing the MTF of gated x-ray pinhole cameras are discussed, with results specific to the FXI presented.

  10. High spatial resolution soft-x-ray microscopy

    SciTech Connect

    Meyer-Ilse, W.; Medecki, H.; Brown, J.T.

    1997-04-01

    A new soft x-ray microscope (XM-1) with high spatial resolution has been constructed by the Center for X-ray Optics. It uses bending magnet radiation from beamline 6.1 at the Advanced Light Source, and is used in a variety of projects and applications in the life and physical sciences. Most of these projects are ongoing. The instrument uses zone plate lenses and achieves a resolution of 43 nm, measured over 10% to 90% intensity with a knife edge test sample. X-ray microscopy permits the imaging of relatively thick samples, up to 10 {mu}m thick, in water. XM-1 has an easy to use interface, that utilizes visible light microscopy to precisely position and focus the specimen. The authors describe applications of this device in the biological sciences, as well as in studying industrial applications including structured polymer samples.

  11. Localization-Based Super-Resolution Imaging of Cellular Structures

    PubMed Central

    Kanchanawong, Pakorn; Waterman, Clare M.

    2013-01-01

    Fluorescence microscopy allows direct visualization of fluorescently tagged proteins within cells. However, the spatial resolution of conventional fluorescence microscopes is limited by diffraction to ~250 nm, prompting the development of super-resolution microscopy which offers resolution approaching the scale of single proteins, i.e., ~20 nm. Here, we describe protocols for single molecule localization-based super-resolution imaging, using focal adhesion proteins as an example and employing either photoswitchable fluorophores or photoactivatable fluorescent proteins. These protocols should also be easily adaptable to imaging a broad array of macromolecular assemblies in cells whose components can be fluorescently tagged and assemble into high density structures. PMID:23868582

  12. Infrared super-resolution imaging based on compressed sensing

    NASA Astrophysics Data System (ADS)

    Sui, Xiubao; Chen, Qian; Gu, Guohua; Shen, Xuewei

    2014-03-01

    The theoretical basis of traditional infrared super-resolution imaging method is Nyquist sampling theorem. The reconstruction premise is that the relative positions of the infrared objects in the low-resolution image sequences should keep fixed and the image restoration means is the inverse operation of ill-posed issues without fixed rules. The super-resolution reconstruction ability of the infrared image, algorithm's application area and stability of reconstruction algorithm are limited. To this end, we proposed super-resolution reconstruction method based on compressed sensing in this paper. In the method, we selected Toeplitz matrix as the measurement matrix and realized it by phase mask method. We researched complementary matching pursuit algorithm and selected it as the recovery algorithm. In order to adapt to the moving target and decrease imaging time, we take use of area infrared focal plane array to acquire multiple measurements at one time. Theoretically, the method breaks though Nyquist sampling theorem and can greatly improve the spatial resolution of the infrared image. The last image contrast and experiment data indicate that our method is effective in improving resolution of infrared images and is superior than some traditional super-resolution imaging method. The compressed sensing super-resolution method is expected to have a wide application prospect.

  13. Analysis of the impact of spatial resolution on land/water classifications using high-resolution aerial imagery

    USGS Publications Warehouse

    Enwright, Nicholas M.; Jones, William R.; Garber, Adrienne L.; Keller, Matthew J.

    2014-01-01

    Long-term monitoring efforts often use remote sensing to track trends in habitat or landscape conditions over time. To most appropriately compare observations over time, long-term monitoring efforts strive for consistency in methods. Thus, advances and changes in technology over time can present a challenge. For instance, modern camera technology has led to an increasing availability of very high-resolution imagery (i.e. submetre and metre) and a shift from analogue to digital photography. While numerous studies have shown that image resolution can impact the accuracy of classifications, most of these studies have focused on the impacts of comparing spatial resolution changes greater than 2 m. Thus, a knowledge gap exists on the impacts of minor changes in spatial resolution (i.e. submetre to about 1.5 m) in very high-resolution aerial imagery (i.e. 2 m resolution or less). This study compared the impact of spatial resolution on land/water classifications of an area dominated by coastal marsh vegetation in Louisiana, USA, using 1:12,000 scale colour-infrared analogue aerial photography (AAP) scanned at four different dot-per-inch resolutions simulating ground sample distances (GSDs) of 0.33, 0.54, 1, and 2 m. Analysis of the impact of spatial resolution on land/water classifications was conducted by exploring various spatial aspects of the classifications including density of waterbodies and frequency distributions in waterbody sizes. This study found that a small-magnitude change (1–1.5 m) in spatial resolution had little to no impact on the amount of water classified (i.e. percentage mapped was less than 1.5%), but had a significant impact on the mapping of very small waterbodies (i.e. waterbodies ≤ 250 m2). These findings should interest those using temporal image classifications derived from very high-resolution aerial photography as a component of long-term monitoring programs.

  14. Technical Note: Spatial resolution of proton tomography: Impact of air gap between patient and detector

    SciTech Connect

    Schneider, Uwe; Besserer, Juergen; Hartmann, Matthias

    2012-02-15

    Purpose: Proton radiography and tomography were investigated since the early 1970s because of its low radiation dose, high density resolution, and ability to image directly proton stopping power. However, spatial resolution is still a limiting factor. In this note, preliminary results of the impact of an air gap between detector system and patient on spatial resolution are presented. Methods: Spatial resolution of proton radiography and tomography is governed by multiple Coulomb scattering (MCS) of the protons in the patient. In this note, the authors employ Monte Carlo simulations of protons traversing a 20 cm thick water box. Entrance and exit proton coordinate measurements were simulated for improved spatial resolution. The simulations were performed with and without a 5 cm air gap in front of and behind the patient. Loss of spatial resolution due to the air gap was studied for protons with different initial angular confusion. Results: It was found that spatial resolution is significantly deteriorated when a 5 cm air gap between the position sensitive detector and the patient is included. For a perfect parallel beam spatial resolution worsens by about 40%. Spatial resolution is getting worse with increasing angular confusion and can reach 80%. Conclusions: When proton radiographies are produced by measuring the entrance and exit coordinates of the protons in front of and behind the patient the air gap between the detector and the patient can significantly deteriorate the spatial resolution of the system by up to 80%. An alternative would be to measure in addition to the coordinates also the exit and entrance angles of each proton. In principle, using the air gap size and proton angle, images can be reconstructed with the same spatial resolution than without air gap.

  15. Imaging of electronic defect states in SiO2 and HfSiOx films with sub-nanometer spatial resolution by two-way Single Electron Tunneling Force Mircroscopy

    NASA Astrophysics Data System (ADS)

    Johnson, J. P.; Zheng, N.; Williams, C. C.

    2007-03-01

    Electronic defects in dielectric materials are currently in sharp focus, for nano-technology and quantum information processing. A novel technique has been developed for imaging these states with sub-nanometer spatial resolution. It can be applied to completely non-conducting dielectric films, in contrast to the STM. The method is based on force detected single electron tunneling events to and from the defect states [1-3]. The exponential dependence of the tunneling rate on tip-sample gap provides the same spatial resolution as STM. An oscillating AFM tip is scanned at constant height above the sample surface. A voltage waveform, synchronous with the tip motion is applied. When the tip is above an accessible state, individual electrons shuttle between tip and state with the applied voltage (300 Hz). The two-way tunneling causes a detectable change in tip resonance. Images of SiO2 and HfSiOx films show a repeatable, random array of individual ``point-like'' defect states, some with sub-nanometer width. Spectroscopic measurements of the defect energy are also performed by this approach. The new method and an analysis of the defects in SiO2 and HfSiOx will be presented. [1] E Bussman et al., Appl. Phys. Lett. 85, 2538 (2004) [2] E Bussman and CC Williams, Appl. Phys. Lett. 88, 263108 (2006) [3] E Bussman et al., Nano Lett. 6, 2577 (2006)

  16. Full-field spatially incoherent illumination interferometry: a spatial resolution almost insensitive to aberrations.

    PubMed

    Xiao, Peng; Fink, Mathias; Boccara, A Claude

    2016-09-01

    We show that with spatially incoherent illumination, the point spread function (PSF) width/spatial resolution of an imaging interferometer like that used in full-field optical coherence tomography (OCT) is almost insensitive to aberrations. In these systems, aberrations mostly induce a reduction of the signal level that leads to a loss of the signal-to-noise ratio without broadening the system PSF. This is demonstrated by comparison with traditional scanning OCT and wide-field OCT with spatially coherent illuminations. Theoretical analysis and numerical calculation as well as experimental results are provided to show this specific merit of incoherent illumination in full-field OCT. To the best of our knowledge, this is the first time that such a result has been demonstrated. PMID:27607937

  17. A methodological approach toward high-resolution surface wave imaging of the San Jacinto Fault Zone using ambient-noise recordings at a spatially dense array

    NASA Astrophysics Data System (ADS)

    Roux, Philippe; Moreau, Ludovic; Lecointre, Albanne; Hillers, Gregor; Campillo, Michel; Ben-Zion, Yehuda; Zigone, Dimitri; Vernon, Frank

    2016-05-01

    We present a new technique for deriving detailed information on seismic velocities of the sub-surface material from continuous ambient noise recorded by spatially dense seismic arrays. This method uses iterative double beamforming between various subarrays to extract surface-wave contributions from the ambient-noise data in complex environments with unfavorable noise-source distributions. The iterative double beamforming extraction makes it possible to retrieve large amounts of Rayleigh wave travel-time information in a wide frequency band. The method is applied to data recorded by a highly dense Nodal array with 1,108 vertical geophones, centered on the damage zone of the Clark branch of the San Jacinto Fault Zone south of Anza, California. The array covers a region of ˜650 m x 700 m, with instrument spacing of 10 m to 30 m, and continuous recording at 500 samples/s over 30 days in 2014. Using this iterative double beamforming on subarrays of 25 sensors and cross-correlations between all of the station pairs, we separate surface waves from body waves that are abundant in the raw cross-correlation data. Focusing solely on surface waves, maps of travel times are obtained at different frequencies with unprecedented accuracy at each point of a 15-m-spacing grid. Group velocity inversions at 2 Hz to 4 Hz reveal depth and lateral variations in the structural properties within and around the San Jacinto Fault Zone in the study area. This method can be used over wider frequency ranges and can be combined with other imaging techniques, such as eikonal tomography, to provide unprecedented detailed structural images of the sub-surface material.

  18. A methodological approach towards high-resolution surface wave imaging of the San Jacinto Fault Zone using ambient-noise recordings at a spatially dense array

    NASA Astrophysics Data System (ADS)

    Roux, Philippe; Moreau, Ludovic; Lecointre, Albanne; Hillers, Gregor; Campillo, Michel; Ben-Zion, Yehuda; Zigone, Dimitri; Vernon, Frank

    2016-08-01

    We present a new technique for deriving detailed information on seismic velocities of the subsurface material from continuous ambient noise recorded by spatially dense seismic arrays. This method uses iterative double beamforming between various subarrays to extract surface wave contributions from the ambient-noise data in complex environments with unfavourable noise-source distributions. The iterative double beamforming extraction makes it possible to retrieve large amounts of Rayleigh wave traveltime information in a wide frequency band. The method is applied to data recorded by a highly dense Nodal array with 1108 vertical geophones, centred on the damage zone of the Clark branch of the San Jacinto Fault Zone south of Anza, California. The array covers a region of ˜650 × 700 m2, with instrument spacing of 10-30 m, and continuous recording at 500 samples s-1 over 30 d in 2014. Using this iterative double beamforming on subarrays of 25 sensors and cross-correlations between all of the station pairs, we separate surface waves from body waves that are abundant in the raw cross-correlation data. Focusing solely on surface waves, maps of traveltimes are obtained at different frequencies with unprecedented accuracy at each point of a 15-m-spacing grid. Group velocity inversions at 2-4 Hz reveal depth and lateral variations in the structural properties within and around the San Jacinto Fault Zone in the study area. This method can be used over wider frequency ranges and can be combined with other imaging techniques, such as eikonal tomography, to provide unprecedented detailed structural images of the subsurface material.

  19. Super Resolution Image of Yogi

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Yogi is a meter-size rock about 5 meters northwest of the Mars Pathfinder lander and was the second rock visited by the Sojourner Rover's alpha proton X-ray spectrometer (APXS) instrument. This mosaic shows super resolution techniques applied to the second APXS target rock, which was poorly illuminated in the rover's forward camera view taken before the instrument was deployed. Super resolution was applied to help to address questions about the texture of this rock and what it might tell us about its mode of origin.

    This mosaic of Yogi was produced by combining four 'Super Pan' frames taken with the IMP camera. This composite color mosaic consists of 7 frames from the right eye, taken with different color filters that were enlarged by 500% and then co-added using Adobe Photoshop to produce, in effect, a super-resolution panchromatic frame that is sharper than an individual frame would be. This panchromatic frame was then colorized with the red, green, and blue filtered images from the same sequence. The color balance was adjusted to approximate the true color of Mars. Shadows were processed separately from the rest of the rock and combined with the rest of the scene to bring out details in the shadow of Yogi that would be too dark to view at the same time as the sunlit surfaces.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. JPL is a division of the California Institute of Technology (Caltech).

  20. X-Ray tomography with micrometer spatial resolution

    NASA Astrophysics Data System (ADS)

    Raven, Carsten; Snigirev, Anatoly A.; Koch, Andreas; Snigireva, Irina; Kohn, Victor

    1997-10-01

    3D computed tomographic images with micrometer resolution were made in phase-contrast mode with high energy x-rays at a third generation synchrotron source. The phase-contrast technique enables one to obtain information not only about the amplitude of the wave field behind the object and thus about the absorption, but also about the refractive index distribution inside the sample. Increasing the x-ray energy from the soft x-ray region up to 10-60 keV simplifies the experimental setup and opens the possibility to study organic samples at room-temperature and under normal pressure conditions. The projection data is recorded with a fast, high-resolution x-ray camera consisting of a 5 micrometers thin YAG scintillator crystal, a visible light microscope optics and a slow scan 1k X 1k CCD camera. The spatial resolution of phase-contrast microtomography is currently limited by the resolution of the x-ray detector to about 1-2 micrometers . First applications in biology and geophysics are shown.

  1. High-resolution Urban Image Classification Using Extended Features

    SciTech Connect

    Vatsavai, Raju

    2011-01-01

    High-resolution image classification poses several challenges because the typical object size is much larger than the pixel resolution. Any given pixel (spectral features at that location) by itself is not a good indicator of the object it belongs to without looking at the broader spatial footprint. Therefore most modern machine learning approaches that are based on per-pixel spectral features are not very effective in high- resolution urban image classification. One way to overcome this problem is to extract features that exploit spatial contextual information. In this study, we evaluated several features in- cluding edge density, texture, and morphology. Several machine learning schemes were tested on the features extracted from a very high-resolution remote sensing image and results were presented.

  2. COMPLEX ORGANIC MOLECULES AT HIGH SPATIAL RESOLUTION TOWARD ORION-KL. I. SPATIAL SCALES

    SciTech Connect

    Widicus Weaver, Susanna L.; Friedel, Douglas N. E-mail: friedel@astro.illinois.edu

    2012-08-01

    Here we present high spatial resolution (<1'') observations of molecular emission in Orion-KL conducted using the Combined Array for Research in Millimeter-wave Astronomy. This work was motivated by recent millimeter continuum imaging studies of this region conducted at a similarly high spatial resolution, which revealed that the bulk of the emission arises from numerous compact sources, rather than the larger-scale extended structures typically associated with the Orion Hot Core and Compact Ridge. Given that the spatial extent of molecular emission greatly affects the determination of molecular abundances, it is important to determine the true spatial scale for complex molecules in this region. Additionally, it has recently been suggested that the relative spatial distributions of complex molecules in a source might give insight into the chemical mechanisms that drive complex chemistry in star-forming regions. In order to begin to address these issues, this study seeks to determine the spatial distributions of ethyl cyanide [C{sub 2}H{sub 5}CN], dimethyl ether [(CH{sub 3}){sub 2}O], methyl formate [HCOOCH{sub 3}], formic acid [HCOOH], acetone [(CH{sub 3}){sub 2}CO], SiO, methanol [CH{sub 3}OH], and methyl cyanide [CH{sub 3}CN] in Orion-KL at {lambda} = 3 mm. We find that for all observed molecules, the molecular emission arises from multiple components of the cloud that include a range of spatial scales and physical conditions. Here, we present the results of these observations and discuss the implications for studies of complex molecules in star-forming regions.

  3. A method for generating high resolution satellite image time series

    NASA Astrophysics Data System (ADS)

    Guo, Tao

    2014-10-01

    There is an increasing demand for satellite remote sensing data with both high spatial and temporal resolution in many applications. But it still is a challenge to simultaneously improve spatial resolution and temporal frequency due to the technical limits of current satellite observation systems. To this end, much R&D efforts have been ongoing for years and lead to some successes roughly in two aspects, one includes super resolution, pan-sharpen etc. methods which can effectively enhance the spatial resolution and generate good visual effects, but hardly preserve spectral signatures and result in inadequate analytical value, on the other hand, time interpolation is a straight forward method to increase temporal frequency, however it increase little informative contents in fact. In this paper we presented a novel method to simulate high resolution time series data by combing low resolution time series data and a very small number of high resolution data only. Our method starts with a pair of high and low resolution data set, and then a spatial registration is done by introducing LDA model to map high and low resolution pixels correspondingly. Afterwards, temporal change information is captured through a comparison of low resolution time series data, and then projected onto the high resolution data plane and assigned to each high resolution pixel according to the predefined temporal change patterns of each type of ground objects. Finally the simulated high resolution data is generated. A preliminary experiment shows that our method can simulate a high resolution data with a reasonable accuracy. The contribution of our method is to enable timely monitoring of temporal changes through analysis of time sequence of low resolution images only, and usage of costly high resolution data can be reduces as much as possible, and it presents a highly effective way to build up an economically operational monitoring solution for agriculture, forest, land use investigation

  4. EFTEM spectrum imaging at high-energy resolution.

    PubMed

    Schaffer, Bernhard; Kothleitner, Gerald; Grogger, Werner

    2006-01-01

    This paper deals with the application of high-energy resolution EFTEM image series and the corrections needed for reliable data interpretation. The detail of spectral information gained from an image series is largely determined by the intrinsic energy resolution. In this work we show that energy resolution values of as low as 0.8 eV in spectra extracted from EFTEM image series can be obtained with a small energy-selecting slit. At this resolution level aberrations of the energy filter, in particular the non-isochromaticity, can no longer be neglected. We show that the four most prominent factors for EFTEM image series data correction--spatial drift, non-isochromaticity, energy drift and image distortion--must not be treated independently but have to be corrected in unison. We present an efficient algorithm for this correction, and demonstrate the applied correction for the case of a GaN/AlN multilayer sample. PMID:16872748

  5. Flat coil-based tunnel diode oscillator enabling to detect the real shape of the superconductive transition curve and capable of imaging the properties of HTSC films with high spatial resolution

    NASA Astrophysics Data System (ADS)

    Gevorgyan, Samvel; Shirinyan, Hovsep; Manukyan, Artashes; Sharoyan, Eduard; Takeo, Masakatsu; Polyanskii, Anatolii; Sarkisyan, Albert; Matsushita, Teruo

    2004-03-01

    Owing to a pick-up coil's flat design, relatively low MHz-range operation frequency, and six orders relative resolution a flat coil-based tunnel diode oscillator has advantages, compared to all other methods. They become crucial in studies with thin high-Tc superconductivity (HTSC) materials (with small signals), especially at the start of the Cooper pairs' formation. Due to this the superconductivity precursor ‘paramagnetic' effect was detected recently in YBaCuO films at N/S transition. It precedes Meissner ejection and specifies details of the shape of the transition curve. We discuss the influence of the currents on this effect, and the relationship between the quality of the material and the shape of the effect. A new imaging device has also been created based on this test method (using a focused He-Ne laser beam as a probing signal), capable of imaging the properties of HTSC films with ∼3 μm spatial resolution. The method is based on detection of the inductance and Q-factor value changes of a single-layer flat coil, placed at the face of the sample. This leads to frequency and/or amplitude changes of the stable oscillator. The test device enabled 2D-mapping of the grain structure of a bridge-shaped YBaCuO film. Basically, the method is capable of imaging 2D-current distribution in thin HTS with sub-μm spatial-resolution, using non-bolometric response. However, the achieved resolution ∼3 μm of a bolometric nature (in a given device with 3.5 mm-size coil) by no means is limited by the abilities of the method, but mainly, it depends on how narrowly it is possible to focus the probing beam, while the own resolution of a present flat coil-based technique is better than 0.1 μm, and can be improved essentially by reducing the coil size.

  6. Detecting liquid threats with x-ray diffraction imaging (XDi) using a hybrid approach to navigate trade-offs between photon count statistics and spatial resolution

    NASA Astrophysics Data System (ADS)

    Skatter, Sondre; Fritsch, Sebastian; Schlomka, Jens-Peter

    2016-05-01

    The performance limits were explored for an X-ray Diffraction based explosives detection system for baggage scanning. This XDi system offers 4D imaging that comprises three spatial dimensions with voxel sizes in the order of ~(0.5cm)3, and one spectral dimension for material discrimination. Because only a very small number of photons are observed for an individual voxel, material discrimination cannot work reliably at the voxel level. Therefore, an initial 3D reconstruction is performed, which allows the identification of objects of interest. Combining all the measured photons that scattered within an object, more reliable spectra are determined on the object-level. As a case study we looked at two liquid materials, one threat and one innocuous, with very similar spectral characteristics, but with 15% difference in electron density. Simulations showed that Poisson statistics alone reduce the material discrimination performance to undesirable levels when the photon counts drop to 250. When additional, uncontrolled variation sources are considered, the photon count plays a less dominant role in detection performance, but limits the performance also for photon counts of 500 and higher. Experimental data confirmed the presence of such non-Poisson variation sources also in the XDi prototype system, which suggests that the present system can still be improved without necessarily increasing the photon flux, but by better controlling and accounting for these variation sources. When the classification algorithm was allowed to use spectral differences in the experimental data, the discrimination between the two materials improved significantly, proving the potential of X-ray diffraction also for liquid materials.

  7. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (∼0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ∼ 3 km s‑1) as well as modest non-thermal velocities (with an average of ∼24 km s‑1 and the peak of the distribution at ∼15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  8. High Spatial Resolution Fe XII Observations of Solar Active Regions

    NASA Astrophysics Data System (ADS)

    Testa, Paola; De Pontieu, Bart; Hansteen, Viggo

    2016-08-01

    We use UV spectral observations of active regions with the Interface Region Imaging Spectrograph (IRIS) to investigate the properties of the coronal Fe xii 1349.4 Å emission at unprecedented high spatial resolution (˜0.33″). We find that by using appropriate observational strategies (i.e., long exposures, lossless compression), Fe xii emission can be studied with IRIS at high spatial and spectral resolution, at least for high-density plasma (e.g., post-flare loops and active region moss). We find that upper transition region (TR; moss) Fe xii emission shows very small average Doppler redshifts ({v}{{D}} ˜ 3 km s‑1) as well as modest non-thermal velocities (with an average of ˜24 km s‑1 and the peak of the distribution at ˜15 km s‑1). The observed distribution of Doppler shifts appears to be compatible with advanced three-dimensional radiative MHD simulations in which impulsive heating is concentrated at the TR footpoints of a hot corona. While the non-thermal broadening of Fe xii 1349.4 Å peaks at similar values as lower resolution simultaneous Hinode Extreme Ultraviolet Imaging Spectrometer (EIS) measurements of Fe xii 195 Å, IRIS observations show a previously undetected tail of increased non-thermal broadening that might be suggestive of the presence of subarcsecond heating events. We find that IRIS and EIS non-thermal line broadening measurements are affected by instrumental effects that can only be removed through careful analysis. Our results also reveal an unexplained discrepancy between observed 195.1/1349.4 Å Fe xii intensity ratios and those predicted by the CHIANTI atomic database.

  9. Study of the spatial resolution for binary readout detectors

    NASA Astrophysics Data System (ADS)

    Yonamine, R.; Maerschalk, T.; Lentdecker, G. De

    2016-07-01

    Often the binary readout is proposed for high granularity detectors to reduce the generated data volume to be readout at the price of a somewhat reduced spatial resolution compared to an analogue readout. We have been studying single hit resolutions obtained with a binary readout using simulations as well as analytical approaches. In this note we show that the detector geometry could be optimized to offer an equivalent spatial resolution than with an analogue readout.

  10. Optoacoustic imaging quality enhancement based on geometrical super-resolution method

    NASA Astrophysics Data System (ADS)

    He, Hailong; Mandal, Subhamoy; Buehler, Andreas; Deán-Ben, X. Luís.; Razansky, Daniel; Ntziachristos, Vasilis

    2016-03-01

    In optoacoustic imaging, the resolution and image quality in a certain imaging position usually cannot be enhanced without changing the imaging configuration. Post-reconstruction image processing methods offer a new possibility to improve image quality and resolution. We have developed a geometrical super-resolution (GSR) method which uses information from spatially separated frames to enhance resolution and contrast in optoacoustic images. The proposed method acquires several low resolution images from the same object located at different positions inside the imaging plane. Thereafter, it applies an iterative registration algorithm to integrate the information in the acquired set of images to generate a single high resolution image. Herein, we present the method and evaluate its performance in simulation and phantom experiments, and results show that geometrical super-resolution techniques can be a promising alternative to enhance resolution in optoacoustic imaging.

  11. Resolution enhancement of computed radiography images using two orthogonal tilts

    NASA Astrophysics Data System (ADS)

    Pollmann, Steven I.; Norley, Chris J. D.; Yuan, Xunhua; Holdsworth, David W.

    2012-03-01

    Limitations to the spatial resolution of current digital x-ray systems are bounded by the physical characteristics of the xray detector. However, the need to image smaller structures provides motivation to develop high-resolution x-ray detector systems for use with computed radiographic, and tomographic x-ray systems. We report the implementation of a tilted detector technique (TDT) to attain near isotropic resolution enhancement by combining two orthogonal image views, acquired with existing detector hardware tilted at a fixed angle. Images were acquired using a ceiling-mounted x-ray unit (Proteus XR/a, GE Medical Systems, 50kVp, 250mAs). Images were digitized using a Fujifilm Capsula X CR system, from a 35×43cm detector cassette placed on an angulated stand, featuring a 3520×4280 image matrix with an in-plane pixel spacing of 0.1mm. Three images were acquired: two for use with our TDT; and one for comparison, with no detector tilt. Performance was determined by using two line-pair phantoms (Models 07-521 and 07-533, Nuclear Associates) placed orthogonally to each other in the field of view. Custom software corrected for perspective distortion, co-registered and combined the tilted-detector images into a single higher-resolution image. Following unwarping and co-registration, the limiting spatial resolution of an image obtained via the weighted combination of the two orthogonal views (8 lp/mm) is found to be superior to that of a single view acquired with no detector tilt (5 lp/mm). This novel technique shows significant improvement in the spatial resolution of x-ray image acquisitions, using existing x-ray components and detector hardware.

  12. USGS MODERATE RESOLUTION LAND IMAGING

    NASA Astrophysics Data System (ADS)

    Dwyer, J. L.; Willems, J. S.

    2009-12-01

    For the past 37 years, the Landsat series of satellites has provided continuous data of the Earth’s land masses, coastal boundaries, and coral reefs creating an unprecedented comprehensive record of landscape dynamics. Landsat 5 and 7 continue to capture hundreds of images of the Earth’s surface each day. In mid-December 2008, the USGS made the entire Landsat archive available to everyone, anywhere, at anytime via the Internet at no cost to the user. The opening of the Landsat archive, the longest record of the terrestrial environment, is a revolution that will affect the future of moderate resolution Earth observations, enabling scientists to address research questions and develop operational applications that were previously cost prohibitive. In addition, the time-series data richness of the archive allows for the development of essential climate variables used to monitor the causes and consequences of lands cover change as a function of climate variability and anthropogenic influences. Landsat is unique as a single source of systematic, global land observations in terms of the number of spectral bands, global collection capacity, image quality, and the proven fidelity of its calibrated sensors. Through the Land Remote Sensing Policy Act of 1992 and the Presidential Decision Direct/NSTC-3 (1994), as amended on October 16, 2000, the U.S Geological Survey (USGS) is charged to ensure the continuity of Landsat data. To accomplish this, the USGS, in partnership with the National Aeronautics and Space Administration (NASA), is currently preparing for the launch of the Landsat Data Continuity Mission (LDCM) in December 2012, the eighth satellite in the Landsat Program. The LDCM will ensure the continuation of the Landsat record and will consist of significant improvements in radiometric response and additional spectral bands, from which high quality data products will be generated and accessible to users at no cost.

  13. Large-scale proton radiography with micrometer spatial resolution using femtosecond petawatt laser system

    NASA Astrophysics Data System (ADS)

    Wang, W. P.; Shen, B. F.; Zhang, H.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Yu, L. H.; Chu, Y. X.; Li, Y. Y.; Xu, T. J.; Zhang, H.; Zhai, S. H.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.

    2015-10-01

    An image of dragonfly with many details is obtained by the fundamental property of the high-energy proton source on a femtosecond petawatt laser system. Equal imaging of the dragonfly and high spatial resolution on the micrometer scale are simultaneously obtained. The head, wing, leg, tail, and even the internal tissue structures are clearly mapped in detail by the proton beam. Experiments show that image blurring caused by multiple Coulomb scattering can be reduced to a certain extent and the spatial resolution can be increased by attaching the dragonfly to the RCFs, which is consistent with theoretical assumptions.

  14. Large-scale proton radiography with micrometer spatial resolution using femtosecond petawatt laser system

    SciTech Connect

    Wang, W. P.; Shen, B. F. Zhang, H.; Lu, X. M.; Wang, C.; Liu, Y. Q.; Yu, L. H.; Chu, Y. X.; Li, Y. Y.; Xu, T. J.; Zhang, H.; Zhai, S. H.; Leng, Y. X.; Liang, X. Y.; Li, R. X.; Xu, Z. Z.

    2015-10-15

    An image of dragonfly with many details is obtained by the fundamental property of the high-energy proton source on a femtosecond petawatt laser system. Equal imaging of the dragonfly and high spatial resolution on the micrometer scale are simultaneously obtained. The head, wing, leg, tail, and even the internal tissue structures are clearly mapped in detail by the proton beam. Experiments show that image blurring caused by multiple Coulomb scattering can be reduced to a certain extent and the spatial resolution can be increased by attaching the dragonfly to the RCFs, which is consistent with theoretical assumptions.

  15. Robust Tips for High Resolution Chemical Imaging

    NASA Astrophysics Data System (ADS)

    Barrios, Carlos; Malkovskiy, Andrey; Kisliuk, Alexander; Sokolov, Alexei; Foster, Mark

    2009-03-01

    Tip enhanced Raman spectroscopy (TERS) combines scanning probe microscopy with Raman spectroscopy, taking advantage of apertureless near-field optics. A plasmonic structure at the apex of a sharp tip provides signal amplification required for chemical imaging. Plasmonic structure characteristics such as roughness, shape, and radius determine the spatial resolution and signal enhancement. Unfortunately, noble metal nanostructures have limited lifetimes due to mechanical, chemical, and thermal degradation. Lifetime extension requires slowing degradation processes while minimizing unfavorable influences on the optical response. An ultrathin SiOx protective coating provides lifetime improvement of silver plasmonic nanostructures on SPM tips. Controlled physical vapor deposition (PVD) of Al can be used to create ultrathin (˜2-3 nm) Al2O3 coatings that improve significantly the stability and wear resistance of plasmonics structures without substantial degradation of optical properties. Such a coating completely prevented decay in plasmonic activity after 40 days of use.

  16. Pixelated filters for spatial imaging

    NASA Astrophysics Data System (ADS)

    Mathieu, Karine; Lequime, Michel; Lumeau, Julien; Abel-Tiberini, Laetitia; Savin De Larclause, Isabelle; Berthon, Jacques

    2015-10-01

    Small satellites are often used by spatial agencies to meet scientific spatial mission requirements. Their payloads are composed of various instruments collecting an increasing amount of data, as well as respecting the growing constraints relative to volume and mass; So small-sized integrated camera have taken a favored place among these instruments. To ensure scene specific color information sensing, pixelated filters seem to be more attractive than filter wheels. The work presented here, in collaboration with Institut Fresnel, deals with the manufacturing of this kind of component, based on thin film technologies and photolithography processes. CCD detectors with a pixel pitch about 30 μm were considered. In the configuration where the matrix filters are positioned the closest to the detector, the matrix filters are composed of 2x2 macro pixels (e.g. 4 filters). These 4 filters have a bandwidth about 40 nm and are respectively centered at 550, 700, 770 and 840 nm with a specific rejection rate defined on the visible spectral range [500 - 900 nm]. After an intense design step, 4 thin-film structures have been elaborated with a maximum thickness of 5 μm. A run of tests has allowed us to choose the optimal micro-structuration parameters. The 100x100 matrix filters prototypes have been successfully manufactured with lift-off and ion assisted deposition processes. High spatial and spectral characterization, with a dedicated metrology bench, showed that initial specifications and simulations were globally met. These excellent performances knock down the technological barriers for high-end integrated specific multi spectral imaging.

  17. Advances in Spectral-Spatial Classification of Hyperspectral Images

    NASA Technical Reports Server (NTRS)

    Fauvel, Mathieu; Tarabalka, Yuliya; Benediktsson, Jon Atli; Chanussot, Jocelyn; Tilton, James C.

    2012-01-01

    Recent advances in spectral-spatial classification of hyperspectral images are presented in this paper. Several techniques are investigated for combining both spatial and spectral information. Spatial information is extracted at the object (set of pixels) level rather than at the conventional pixel level. Mathematical morphology is first used to derive the morphological profile of the image, which includes characteristics about the size, orientation and contrast of the spatial structures present in the image. Then the morphological neighborhood is defined and used to derive additional features for classification. Classification is performed with support vector machines using the available spectral information and the extracted spatial information. Spatial post-processing is next investigated to build more homogeneous and spatially consistent thematic maps. To that end, three presegmentation techniques are applied to define regions that are used to regularize the preliminary pixel-wise thematic map. Finally, a multiple classifier system is defined to produce relevant markers that are exploited to segment the hyperspectral image with the minimum spanning forest algorithm. Experimental results conducted on three real hyperspectral images with different spatial and spectral resolutions and corresponding to various contexts are presented. They highlight the importance of spectral-spatial strategies for the accurate classification of hyperspectral images and validate the proposed methods.

  18. Super-resolution in diffusion-weighted imaging.

    PubMed

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

    2011-01-01

    Diffusion-weighted imaging (DWI) enables non-invasive investigation and characterization of the white-matter but suffers from a relatively poor resolution. In this work we propose a super-resolution reconstruction (SRR) technique based on the acquisition of multiple anisotropic orthogonal DWI scans. We address the problem of patient motions by aligning the volumes both in space and in q-space. The SRR is formulated as a maximum a posteriori (MAP) problem. It relies on a volume acquisition model which describes the generation of the acquired scans from the unknown high-resolution image. It enables the introduction of image priors that exploit spatial homogeneity and enables regularized solutions. We detail our resulting SRR optimization procedure and report various experiments including numerical simulations, synthetic SRR scenario and real world SRR scenario. Super-resolution reconstruction in DWI may enable DWI to be performed with unprecedented resolution. PMID:21995021

  19. Multiresponse imaging system design for improved resolution

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Fales, Carl L.; Huck, Friedrich O.; Rahman, Zia-Ur; Reichenbach, Stephen E.

    1991-01-01

    Multiresponse imaging is a process that acquires A images, each with a different optical response, and reassembles them into a single image with an improved resolution that can approach 1/sq rt A times the photodetector-array sampling lattice. Our goals are to optimize the performance of this process in terms of the resolution and fidelity of the restored image and to assess the amount of information required to do so. The theoretical approach is based on the extension of both image restoration and rate-distortion theories from their traditional realm of signal processing to image processing which includes image gathering and display.

  20. Super-Resolution Optical Imaging of Biomass Chemical-Spatial Structure: Cooperative Research and Development Final Report, CRADA Number CRD-10-410

    SciTech Connect

    Ding, S. Y.

    2013-06-01

    The overall objective for this project is to characterize and develop new methods to visualize the chemical spatial structure of biomass at varying stages of the biomass degradation processes in situ during the process.

  1. Subsurface Super-resolution Imaging of Unstained Polymer Nanostructures

    PubMed Central

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

    2016-01-01

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

  2. Subsurface Super-resolution Imaging of Unstained Polymer Nanostructures.

    PubMed

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

    2016-01-01

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

  3. Subsurface Super-resolution Imaging of Unstained Polymer Nanostructures

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  4. The influences of different spatial resolutions on the characteristics of T2 relaxation times in articular cartilage: A coarse-graining study of the microscopic magnetic resonance imaging data.

    PubMed

    Zhuang, Zhiguo; Lee, Ji Hyun; Badar, Farid; Xu, Jianrong; Xia, Yang

    2016-08-01

    Microscopic magnetic resonance imaging (µMRI) T2 data from canine cartilage at different tibial locations were analyzed to investigate the influences of spatial resolution and pixel position on the T2 sensitivity to osteoarthritis (OA). Five experimental factors were investigated: inaccurate pixel position, different pixel resolutions, different specimen orientations in the magnetic field, topographical variations over the tibial surface, and different OA stages. A number of significant trends were identified in this analysis, which shows the subtle but substantial influences to our abilities of detecting OA due to T2 changes. In particular, any deviation in locating the cartilage pixels may result in erratic values near the cartilage surface. Significant differences were found in T2 values between nearly any two comparison-groups under all resolutions both in the meniscus-covered and -uncovered areas, which were also showed interaction between the OA degradation stages. This multiresolution project should help to improve the detection sensitivities of MRI toward cartilage degeneration. Microsc. Res. Tech. 79:754-765, 2016. © 2016 Wiley Periodicals, Inc. PMID:27297720

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

    PubMed

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

    2016-08-01

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

  6. Correcting spurious resolution in defocused images

    NASA Astrophysics Data System (ADS)

    Yellott, John I.; Yellott, John W.

    2007-02-01

    Optical modeling suggests that levels of retinal defocus routinely caused by presbyopia should produce phase reversals (spurious resolution-SR) for spatial frequencies in the 2 cycles/letter range known to be critical for reading. Simulations show that such reversals can have a decisive impact on character legibility, and that correcting only this feature of defocused images (by re-reversing contrast sign errors created by defocus) can make unrecognizably blurred letters completely legible. This deblurring impact of SR correction is remarkably unaffected by the magnitude of defocus, as determined by blur-circle size. Both the deblurrring itself and its robustness can be understood from the effect that SR correction has on the defocused pointspread function, which changes from a broad flat cake to a sharply pointed cone. This SR-corrected pointspread acts like a delta function, preserving image shape during convolution regardless of blur-disk size. Curiously, such pointspread functions always contain a narrow annulus of negative light-intensity values whose radius equals the diameter of the blur circle. We show that these properties of SR-correction all stem from the mathematical nature of the Fourier transform of the sign of the optical transfer function, which also accounts for the inevitable low contrast of images pre-corrected for SR.

  7. A study of spatial resolution in pollution exposure modelling

    PubMed Central

    Stroh, Emilie; Harrie, Lars; Gustafsson, Susanna

    2007-01-01

    Background This study is part of several ongoing projects concerning epidemiological research into the effects on health of exposure to air pollutants in the region of Scania, southern Sweden. The aim is to investigate the optimal spatial resolution, with respect to temporal resolution, for a pollutant database of NOx-values which will be used mainly for epidemiological studies with durations of days, weeks or longer periods. The fact that a pollutant database has a fixed spatial resolution makes the choice critical for the future use of the database. Results The results from the study showed that the accuracy between the modelled concentrations of the reference grid with high spatial resolution (100 m), denoted the fine grid, and the coarser grids (200, 400, 800 and 1600 meters) improved with increasing spatial resolution. When the pollutant values were aggregated in time (from hours to days and weeks) the disagreement between the fine grid and the coarser grids were significantly reduced. The results also illustrate a considerable difference in optimal spatial resolution depending on the characteristic of the study area (rural or urban areas). To estimate the accuracy of the modelled values comparison were made with measured NOx values. The mean difference between the modelled and the measured value were 0.6 μg/m3 and the standard deviation 5.9 μg/m3 for the daily difference. Conclusion The choice of spatial resolution should not considerably deteriorate the accuracy of the modelled NOx values. Considering the comparison between modelled and measured values we estimate that an error due to coarse resolution greater than 1 μg/m3 is inadvisable if a time resolution of one day is used. Based on the study of different spatial resolutions we conclude that for urban areas a spatial resolution of 200–400 m is suitable; and for rural areas the spatial resolution could be coarser (about 1600 m). This implies that we should develop a pollutant database that allows

  8. Next generation high resolution adaptive optics fundus imager

    NASA Astrophysics Data System (ADS)

    Fournier, P.; Erry, G. R. G.; Otten, L. J.; Larichev, A.; Irochnikov, N.

    2005-12-01

    The spatial resolution of retinal images is limited by the presence of static and time-varying aberrations present within the eye. An updated High Resolution Adaptive Optics Fundus Imager (HRAOFI) has been built based on the development from the first prototype unit. This entirely new unit was designed and fabricated to increase opto-mechanical integration and ease-of-use through a new user interface. Improved camera systems for the Shack-Hartmann sensor and for the scene image were implemented to enhance the image quality and the frequency of the Adaptive Optics (AO) control loop. An optimized illumination system that uses specific wavelength bands was applied to increase the specificity of the images. Sample images of clinical trials of retinas, taken with and without the system, are shown. Data on the performance of this system will be presented, demonstrating the ability to calculate near diffraction-limited images.

  9. Clinical applications of high-resolution ocular magnetic resonance imaging.

    PubMed

    Tanitame, Keizo; Sone, Takashi; Kiuchi, Yoshiaki; Awai, Kazuo

    2012-11-01

    Magnetic resonance imaging (MRI) using fast sequences with subjects staring at a target can provide motion-free ocular images, and small receiver surface coils make it possible to produce ocular images with high spatial resolution. MRI using half-Fourier single-shot rapid acquisition with a relaxation enhancement sequence as a fast T2-weighted imaging yields useful images for the morphologic diagnosis of ocular diseases, and MRI using a fast spoiled gradient-recalled-echo sequence as a T1-weighted imaging yields additional information by the administration of gadolinium-based contrast material for assessing the vascularity of intraocular tumors. These ocular imaging techniques are useful for the evaluation of patients with angle closure glaucoma, congenital abnormality of ocular globes, intraocular tumors and several types of detachments, as well as patients after ocular surgery. In this pictorial essay, we demonstrate the clinical applications of fast high-resolution ocular MRI with fixation of the subjects' visual foci. PMID:22923185

  10. Image transfer protocol in progressively increasing resolution

    NASA Technical Reports Server (NTRS)

    Percival, Jeffrey W. (Inventor); White, Richard L. (Inventor)

    1999-01-01

    A method of transferring digital image data over a communication link transforms and orders the data so that, as data is received by a receiving station, a low detail version of the image is immediately generated with later transmissions of data providing progressively greater detail in this image. User instructions are accepted, limiting the ultimate resolution of the image or suspending enhancement of the image except in certain user defined regions. When a low detail image is requested followed by a request for a high detailed version of the same image, the originally transmitted data of the low resolution image is not discarded or retransmitted but used with later data to improve the originally transmitted image. Only a single copy of the transformed image need be retained by the transmitting device in order to satisfy requests for different amounts of image detail.

  11. Hyperspectral imagery super-resolution by compressive sensing inspired dictionary learning and spatial-spectral regularization.

    PubMed

    Huang, Wei; Xiao, Liang; Liu, Hongyi; Wei, Zhihui

    2015-01-01

    Due to the instrumental and imaging optics limitations, it is difficult to acquire high spatial resolution hyperspectral imagery (HSI). Super-resolution (SR) imagery aims at inferring high quality images of a given scene from degraded versions of the same scene. This paper proposes a novel hyperspectral imagery super-resolution (HSI-SR) method via dictionary learning and spatial-spectral regularization. The main contributions of this paper are twofold. First, inspired by the compressive sensing (CS) framework, for learning the high resolution dictionary, we encourage stronger sparsity on image patches and promote smaller coherence between the learned dictionary and sensing matrix. Thus, a sparsity and incoherence restricted dictionary learning method is proposed to achieve higher efficiency sparse representation. Second, a variational regularization model combing a spatial sparsity regularization term and a new local spectral similarity preserving term is proposed to integrate the spectral and spatial-contextual information of the HSI. Experimental results show that the proposed method can effectively recover spatial information and better preserve spectral information. The high spatial resolution HSI reconstructed by the proposed method outperforms reconstructed results by other well-known methods in terms of both objective measurements and visual evaluation. PMID:25608212

  12. Hyperspectral Imagery Super-Resolution by Compressive Sensing Inspired Dictionary Learning and Spatial-Spectral Regularization

    PubMed Central

    Huang, Wei; Xiao, Liang; Liu, Hongyi; Wei, Zhihui

    2015-01-01

    Due to the instrumental and imaging optics limitations, it is difficult to acquire high spatial resolution hyperspectral imagery (HSI). Super-resolution (SR) imagery aims at inferring high quality images of a given scene from degraded versions of the same scene. This paper proposes a novel hyperspectral imagery super-resolution (HSI-SR) method via dictionary learning and spatial-spectral regularization. The main contributions of this paper are twofold. First, inspired by the compressive sensing (CS) framework, for learning the high resolution dictionary, we encourage stronger sparsity on image patches and promote smaller coherence between the learned dictionary and sensing matrix. Thus, a sparsity and incoherence restricted dictionary learning method is proposed to achieve higher efficiency sparse representation. Second, a variational regularization model combing a spatial sparsity regularization term and a new local spectral similarity preserving term is proposed to integrate the spectral and spatial-contextual information of the HSI. Experimental results show that the proposed method can effectively recover spatial information and better preserve spectral information. The high spatial resolution HSI reconstructed by the proposed method outperforms reconstructed results by other well-known methods in terms of both objective measurements and visual evaluation. PMID:25608212

  13. Analysis of DOA estimation spatial resolution using MUSIC algorithm

    NASA Astrophysics Data System (ADS)

    Guo, Yue; Wang, Hongyuan; Luo, Bin

    2005-11-01

    This paper presents a performance analysis of the spatial resolution of the direction of arrival (DOA) estimates attained by the multiple signal classification (MUSIC) algorithm for uncorrelated sources. The confidence interval of estimation angle which is much more intuitionistic will be considered as the new evaluation standard for the spatial resolution. Then, based on the statistic method, the qualitative analysis reveals the factors influencing the performance of the MUSIC algorithm. At last, quantitative simulations prove the theoretical analysis result exactly.

  14. [Extracting municipal solid waste dumps based on high resolution images].

    PubMed

    Zhang, Fang-Li; Du, Shi-Hong; Guo, Zhou

    2013-08-01

    The dramatically increasing informal MSW dumps are endangering the urban environment. Remote sensing (RS) technologies are more efficient to monitor and manage municipal solid wastes (MSW) than traditional survey-based methods. In high spatial resolution remotely sensed images, these irregularly distributed dumps have complex compositions and strong heterogeneities, thus it is still hard to extract them automatically no matter the pixel-or object-based image analysis method is used. Therefore, based on the analysis of MSW characteristics, the present study develops a multiresolution strategy to extract MSW dumps by combining image features at both high resolution and resampled low heterogeneity images, while the high resolution images can provide detailed information and the low resolution images can suppress the strong heterogeneities of informal MSW dumps. Taking the QuickBird image covering part of Beijing as an example, this multi-resolution strategy produced a high accuracy (75%), indicating that this multi-resolution strategy is quite effective for extracting the open-air informal MSW dumps. PMID:24159838

  15. Atomic resolution images of graphite in air

    SciTech Connect

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

    1988-12-01

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

  16. Improvement of temporal resolution in blood concentration imaging using NIR speckle patterns

    NASA Astrophysics Data System (ADS)

    Yokoi, Naomichi; Shimatani, Yuichi; Kyoso, Masaki; Funamizu, Hideki; Aizu, Yoshihisa

    2013-06-01

    In the imaging of blood concentration change using near infrared bio-speckles, temporal averaging of speckle images is necessary for speckle reduction. To improve the temporal resolution in blood concentration imaging, use of spatial averaging is investigated to measured data in rat experiments. Results show that three frames in temporal averaging with (2×2) pixels in spatial averaging can be accepted to obtain the temporal resolution of ten concentration images per second.

  17. High spectral resolution airborne short wave infrared hyperspectral imager

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

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

  18. Exploring the spatial resolution of position-sensitive microchannel plate detectors

    NASA Astrophysics Data System (ADS)

    Wiggins, Blake; Siwal, Davinder; Desouza, Romualdo

    2016-03-01

    High amplification and excellent timing make microchannel plate (MCP) detectors excellent devices for detection of photons, electrons, and ions. In addition to providing sub-nanosecond time resolution MCP detectors can also provide spatial resolution, thus making them useful in imaging applications. Use of a resistive anode (RA) is a routinely used approach to make an MCP position-sensitive. The spatial resolution of the RA associated with detection of a single incident electron was determined. Factors impacting the spatial resolution obtained with the RA will be discussed and the achieved spatial resolution of 64 μm (FWHM) will be presented. Recently, a novel approach has been developed to provide position-sensitivity for an MCP detector. In this approach, namely the induced signal approach, the position of the incident particle is determined by sensing the electron cloud emanating from a MCP stack. By utilizing the zero-crossing point of the inherently bipolar signals, a spatial resolution of 466 μm (FWHM) has been achieved. Work to improve the spatial resolution of the induced signal approach further will be presented. Supported by the US DOE NNSA under Award No. DE-NA0002012.

  19. Feasibility study of a high-spatial resolution x-ray computed tomography using sub-pixel shift method

    SciTech Connect

    Yoneyama, Akio Baba, Rika; Sumitani, Kazushi; Hirai, Yasuharu

    2015-02-23

    A high-spatial resolution X-ray computed tomography (CT) adopting a sub-pixel shift method has been developed. By calculating sectional images, using plural CT datasets obtained by scanning the X-ray imager, the spatial resolution can be reduced relative to the sub-pixel size of an X-ray imager. Feasibility observations of a biomedical sample were performed using 12-keV monochromatic synchrotron radiation and a photon-counting X-ray imager 174-μm pixels in size. Four CT measurements were performed to obtain datasets at different positions of the X-ray imager. Fine sectional images were obtained successfully, and the spatial resolution was estimated as 80-μm, which corresponds to just under half the pixel size of the imager. In addition, a fine 3D image was also obtained by scanning the imager two-dimensionally.

  20. Linear mixing model applied to coarse spatial resolution data from multispectral satellite sensors

    NASA Technical Reports Server (NTRS)

    Holben, Brent N.; Shimabukuro, Yosio E.

    1993-01-01

    A linear mixing model was applied to coarse spatial resolution data from the NOAA Advanced Very High Resolution Radiometer. The reflective component of the 3.55-3.95 micron channel was used with the two reflective channels 0.58-0.68 micron and 0.725-1.1 micron to run a constrained least squares model to generate fraction images for an area in the west central region of Brazil. The fraction images were compared with an unsupervised classification derived from Landsat TM data acquired on the same day. The relationship between the fraction images and normalized difference vegetation index images show the potential of the unmixing techniques when using coarse spatial resolution data for global studies.

  1. Moderate Resolution Imaging Spectroradiometer (MODIS) Overview

    USGS Publications Warehouse

    U.S. Geological Survey

    2008-01-01

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

  2. High-Resolution and Animal Imaging Instrumentation and Techniques

    NASA Astrophysics Data System (ADS)

    Belcari, Nicola; Guerra, AlbertoDel

    During the last decade we have observed a growing interest in "in vivo" imaging techniques for small animals. This is due to the necessity of studying biochemical processes at a molecular level for pharmacology, genetic, and pathology investigations. This field of research is usually called "molecular imaging."Advances in biological understanding have been accompanied by technological advances in instrumentation and techniques and image-reconstruction software, resulting in improved image quality, visibility, and interpretation. The main technological challenge is then the design of systems with high spatial resolution and high sensitivity.

  3. Image super-resolution via adaptive filtering and regularization

    NASA Astrophysics Data System (ADS)

    Ren, Jingbo; Wu, Hao; Dong, Weisheng; Shi, Guangming

    2014-11-01

    Image super-resolution (SR) is widely used in the fields of civil and military, especially for the low-resolution remote sensing images limited by the sensor. Single-image SR refers to the task of restoring a high-resolution (HR) image from the low-resolution image coupled with some prior knowledge as a regularization term. One classic method regularizes image by total variation (TV) and/or wavelet or some other transform which introduce some artifacts. To compress these shortages, a new framework for single image SR is proposed by utilizing an adaptive filter before regularization. The key of our model is that the adaptive filter is used to remove the spatial relevance among pixels first and then only the high frequency (HF) part, which is sparser in TV and transform domain, is considered as the regularization term. Concretely, through transforming the original model, the SR question can be solved by two alternate iteration sub-problems. Before each iteration, the adaptive filter should be updated to estimate the initial HF. A high quality HF part and HR image can be obtained by solving the first and second sub-problem, respectively. In experimental part, a set of remote sensing images captured by Landsat satellites are tested to demonstrate the effectiveness of the proposed framework. Experimental results show the outstanding performance of the proposed method in quantitative evaluation and visual fidelity compared with the state-of-the-art methods.

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

    PubMed Central

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

    2010-01-01

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

  5. Preliminary frequency-domain analysis for the reconstructed spatial resolution of muon tomography

    NASA Astrophysics Data System (ADS)

    Yu, B.; Zhao, Z.; Wang, X.; Wang, Y.; Wu, D.; Zeng, Z.; Zeng, M.; Yi, H.; Luo, Z.; Yue, X.; Cheng, J.

    2014-11-01

    Muon tomography is an advanced technology to non-destructively detect high atomic number materials. It exploits the multiple Coulomb scattering information of muon to reconstruct the scattering density image of the traversed object. Because of the statistics of muon scattering, the measurement error of system and the data incompleteness, the reconstruction is always accompanied with a certain level of interference, which will influence the reconstructed spatial resolution. While statistical noises can be reduced by extending the measuring time, system parameters determine the ultimate spatial resolution that one system can reach. In this paper, an effective frequency-domain model is proposed to analyze the reconstructed spatial resolution of muon tomography. The proposed method modifies the resolution analysis in conventional computed tomography (CT) to fit the different imaging mechanism in muon scattering tomography. The measured scattering information is described in frequency domain, then a relationship between the measurements and the original image is proposed in Fourier domain, which is named as "Muon Central Slice Theorem". Furthermore, a preliminary analytical expression of the ultimate reconstructed spatial is derived, and the simulations are performed for validation. While the method is able to predict the ultimate spatial resolution of a given system, it can also be utilized for the optimization of system design and construction.

  6. Measurement of spatial and density resolutions in x-ray nanocomputed tomography

    NASA Astrophysics Data System (ADS)

    Kawata, Y.; Kageyama, K.; Nakaya, Y.; Niki, N.; Umetani, K.; Yada, K.; Ohmatsu, H.; Eguchi, K.; Kaneko, M.; Moriyama, N.

    2009-02-01

    The latest generation of nano computed tomography (nano-CT) systems with sub-micrometer focus X-ray source is expected to yield non-invasive imaging of internal microstructure of objects with isotropic spatial resolution in the range of hundreds nanometers. Most recently commercial systems have become available for purchase. The quantitative characterization of the performance of nano-CT systems is important for evaluating the accuracy of size and density measurements of fine details in nano-CT images. The point spread function (PSF) and modulation transfer function (MTF) are calculated most commonly from the measurement of thin wire phantom for measuring the spatial resolution of clinical CT systems. However, a consistent method for describing the spatial resolution of nano-CT has not been utilized due to the requirement of a nanowire which is a wire of diameter of the order of tens of nanometers. This paper presents a method to characterize the spatial resolution in x/y-scan plane (transversal orientation) of nano-CT systems using a relatively large microwire in the PSF measurement. In this method, the MTF computed from the PSF is estimated on the basis of a two-Gaussian PSF model. Experimenting with microwire images with three different diameter sizes (3μm, 10μm, 30μm) obtained by the synchrotron radiation CT, we demonstrate the potential usefulness of the method for describing the spatial resolutions of nano-CT systems.

  7. Image super-resolution based on image adaptive decomposition

    NASA Astrophysics Data System (ADS)

    Xie, Qiwei; Wang, Haiyan; Shen, Lijun; Chen, Xi; Han, Hua

    2011-11-01

    In this paper we propose an image super-resolution algorithm based on Gaussian Mixture Model (GMM) and a new adaptive image decomposition algorithm. The new image decomposition algorithm uses local extreme of image to extract the cartoon and oscillating part of image. In this paper, we first decompose an image into oscillating and piecewise smooth (cartoon) parts, then enlarge the cartoon part with interpolation. Because GMM accurately characterizes the oscillating part, we specify it as the prior distribution and then formulate the image super-resolution problem as a constrained optimization problem to acquire the enlarged texture part and finally we obtain a fine result.

  8. Image resolution enhancement via image restoration using neural network

    NASA Astrophysics Data System (ADS)

    Zhang, Shuangteng; Lu, Yihong

    2011-04-01

    Image super-resolution aims to obtain a high-quality image at a resolution that is higher than that of the original coarse one. This paper presents a new neural network-based method for image super-resolution. In this technique, the super-resolution is considered as an inverse problem. An observation model that closely follows the physical image acquisition process is established to solve the problem. Based on this model, a cost function is created and minimized by a Hopfield neural network to produce high-resolution images from the corresponding low-resolution ones. Not like some other single frame super-resolution techniques, this technique takes into consideration point spread function blurring as well as additive noise and therefore generates high-resolution images with more preserved or restored image details. Experimental results demonstrate that the high-resolution images obtained by this technique have a very high quality in terms of PSNR and visually look more pleasant.

  9. Resolution-independent characteristic scale dedicated to satellite images.

    PubMed

    Luo, Bin; Aujol, Jean-François; Gousseau, Yann; Ladjal, Saïd; Maître, Henri

    2007-10-01

    We study the problem of finding the characteristic scale of a given satellite image. This feature is defined so that it does not depend on the spatial resolution of the image. This is a different problem than achieving scale invariance, as often studied in the literature. Our approach is based on the use of a linear scale space and the total variation (TV). The critical scale is defined as the one at which the normalized TV reaches its maximum. It is shown experimentally, both on synthetic and real data, that the computed characteristic scale is resolution independent. PMID:17926932

  10. Super resolution imaging of HER2 gene amplification

    NASA Astrophysics Data System (ADS)

    Okada, Masaya; Kubo, Takuya; Masumoto, Kanako; Iwanaga, Shigeki

    2016-02-01

    HER2 positive breast cancer is currently examined by counting HER2 genes using fluorescence in situ hybridization (FISH)-stained breast carcinoma samples. In this research, two-dimensional super resolution fluorescence microscopy based on stochastic optical reconstruction microscopy (STORM), with a spatial resolution of approximately 20 nm in the lateral direction, was used to more precisely distinguish and count HER2 genes in a FISH-stained tissue section. Furthermore, by introducing double-helix point spread function (DH-PSF), an optical phase modulation technique, to super resolution microscopy, three-dimensional images were obtained of HER2 in a breast carcinoma sample approximately 4 μm thick.

  11. Study of spatial resolution of proton computed tomography using a silicon strip detector

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Izumikawa, T.; Goto, J.; Kawasaki, T.; Kimura, T.

    2014-01-01

    Proton computed tomography (CT) is an imaging technique using a high-energy proton beam penetrating the human body and shows promise for improving the quality of cancer therapy with high-energy particle beams because more accurate electron density distribution measurements can be achieved with proton CT. The deterioration of the spatial resolution owing to multiple Coulomb scattering is, however, a crucial issue. The control of the radiation dose and the long exposure time are also problems to be solved. We have developed a prototype system for proton CT with a silicon strip detector and performed a beam test for imaging. The distribution of the electron density has been measured precisely. We also demonstrated an improvement in spatial resolution by reconstructing the proton trajectory. A spatial resolution of 0.45 mm is achieved for a 25-mm-thick polyethylene object. This will be a useful result for upgrading proton CT application for practical use.

  12. Study of satellite retrieved aerosol optical depth spatial resolution effect on particulate matter concentration prediction

    NASA Astrophysics Data System (ADS)

    Strandgren, J.; Mei, L.; Vountas, M.; Burrows, J. P.; Lyapustin, A.; Wang, Y.

    2014-10-01

    The Aerosol Optical Depth (AOD) spatial resolution effect is investigated for the linear correlation between satellite retrieved AOD and ground level particulate matter concentrations (PM2.5). The Multi-Angle Implementation of Atmospheric Correction (MAIAC) algorithm was developed for the Moderate Resolution Imaging Spectroradiometer (MODIS) for obtaining AOD with a high spatial resolution of 1 km and provides a good dataset for the study of the AOD spatial resolution effect on the particulate matter concentration prediction. 946 Environmental Protection Agency (EPA) ground monitoring stations across the contiguous US have been used to investigate the linear correlation between AOD and PM2.5 using AOD at different spatial resolutions (1, 3 and 10 km) and for different spatial scales (urban scale, meso-scale and continental scale). The main conclusions are: (1) for both urban, meso- and continental scale the correlation between PM2.5 and AOD increased significantly with increasing spatial resolution of the AOD, (2) the correlation between AOD and PM2.5 decreased significantly as the scale of study region increased for the eastern part of the US while vice versa for the western part of the US, (3) the correlation between PM2.5 and AOD is much more stable and better over the eastern part of the US compared to western part due to the surface characteristics and atmospheric conditions like the fine mode fraction.

  13. Semiconductor crystal high resolution imager

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

  14. Spatial resolution limits for the isotropic-3D PET detector X’tal cube

    NASA Astrophysics Data System (ADS)

    Yoshida, Eiji; Tashima, Hideaki; Hirano, Yoshiyuki; Inadama, Naoko; Nishikido, Fumihiko; Murayama, Hideo; Yamaya, Taiga

    2013-11-01

    Positron emission tomography (PET) has become a popular imaging method in metabolism, neuroscience, and molecular imaging. For dedicated human brain and small animal PET scanners, high spatial resolution is needed to visualize small objects. To improve the spatial resolution, we are developing the X’tal cube, which is our new PET detector to achieve isotropic 3D positioning detectability. We have shown that the X’tal cube can achieve 1 mm3 uniform crystal identification performance with the Anger-type calculation even at the block edges. We plan to develop the X’tal cube with even smaller 3D grids for sub-millimeter crystal identification. In this work, we investigate spatial resolution of a PET scanner based on the X’tal cube using Monte Carlo simulations for predicting resolution performance in smaller 3D grids. For spatial resolution evaluation, a point source emitting 511 keV photons was simulated by GATE for all physical processes involved in emission and interaction of positrons. We simulated two types of animal PET scanners. The first PET scanner had a detector ring 14.6 cm in diameter composed of 18 detectors. The second PET scanner had a detector ring 7.8 cm in diameter composed of 12 detectors. After the GATE simulations, we converted the interacting 3D position information to digitalized positions for realistic segmented crystals. We simulated several X’tal cubes with cubic crystals from (0.5 mm)3 to (2 mm)3 in size. Also, for evaluating the effect of DOI resolution, we simulated several X’tal cubes with crystal thickness from (0.5 mm)3 to (9 mm)3. We showed that sub-millimeter spatial resolution was possible using cubic crystals smaller than (1.0 mm)3 even with the assumed physical processes. Also, the weighted average spatial resolutions of both PET scanners with (0.5 mm)3 cubic crystals were 0.53 mm (14.6 cm ring diameter) and 0.48 mm (7.8 cm ring diameter). For the 7.8 cm ring diameter, spatial resolution with 0.5×0.5×1.0 mm3 crystals

  15. Super-resolution reconstruction of terahertz images

    NASA Astrophysics Data System (ADS)

    Li, Yue; Li, Li; Hellicar, Andrew; Guo, Y. Jay

    2008-04-01

    A prototype of terahertz imaging system has been built in CSIRO. This imager uses a backward wave oscillator as the source and a Schottky diode as the detector. It has a bandwidth of 500-700 GHz and a source power 10 mW. The resolution at 610 GHz is about 0.85 mm. Even though this imaging system is a coherent system, only the signal power is measured at the detector and the phase information of the detected wave is lost. Some initial images of tree leaves, chocolate bars and pinholes have been acquired with this system. In this paper, we report experimental results of an attempt to improve the resolution of this imaging system beyond the limitation of diffraction (super-resolution). Due to the lack of phase information needed for applying any coherent super-resolution algorithms, the performance of the incoherent Richardson-Lucy super-resolution algorithm has been evaluated. Experimental results have demonstrated that the Richardson-Lucy algorithm can significantly improve the resolution of these images in some sample areas and produce some artifacts in other areas. These experimental results are analyzed and discussed.

  16. Investigation of spatial resolution characteristics of an in vivo microcomputed tomography system

    NASA Astrophysics Data System (ADS)

    Ghani, Muhammad U.; Zhou, Zhongxing; Ren, Liqiang; Wong, Molly; Li, Yuhua; Zheng, Bin; Yang, Kai; Liu, Hong

    2016-01-01

    The spatial resolution characteristics of an in vivo microcomputed tomography (CT) system was investigated in the in-plane (x-y), cross plane (z) and projection imaging modes. The microCT system utilized in this study employs a flat panel detector with a 127 μm pixel pitch, a microfocus x-ray tube with a focal spot size ranging from 5-30 μm, and accommodates three geometric magnifications (M) of 1.72, 2.54 and 5.10. The in-plane modulation transfer function (MTF) curves were measured as a function of the number of projections, geometric magnification (M), detector binning and reconstruction magnification (MRecon). The in plane cutoff frequency (10% MTF) ranged from 2.31 lp/mm (M=1.72, 2×2 binning) to 12.56 lp/mm (M=5.10, 1×1 binning) and a bar pattern phantom validated those measurements. A slight degradation in the spatial resolution was observed when comparing the image reconstruction with 511 and 918 projections, whose effect was visible at the lower frequencies. Small value of MRecon has little or no impact on the in-plane spatial resolution owning to a stable system. Large value of MRecon has implications on the spatial resolution and it was evident when comparing the bar pattern images reconstructed with MRecon=1.25 and 2.5. The cross plane MTF curves showed that the spatial resolution increased as the slice thickness decreased. The cutoff frequencies in the projection imaging mode yielded slightly higher values as compared to the in-plane and cross plane modes at all the geometric magnifications (M). At M=5.10, the cutoff resolution of the projection and cross plane on an ultra-high contrast resolution bar chip phantom were 14.9 lp/mm and 13-13.5 lp/mm. Due to the finite focal spot size of the x-ray tube, the detector blur and the reconstruction kernel functions, the system's spatial resolution does not reach the limiting spatial resolution as defined by the Nyquist's detector criteria with an ideal point source. The geometric magnification employed in

  17. High resolution imaging with impulse based thermoacoustic tomography

    NASA Astrophysics Data System (ADS)

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

    2011-07-01

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

  18. Large aperture spatial heterodyne imaging spectrometer: Principle and experimental results

    NASA Astrophysics Data System (ADS)

    Xiangli, Bin; Cai, Qisheng; Du, Shusong

    2015-12-01

    A large aperture spatial heterodyne imaging spectrometer (LASHIS) is proposed. It is a kind of pushbroom Fourier transform ultraspectral imager with no moving parts. This imaging spectrometer, based on a Sagnac lateral shearing interferometer combined with a pair of gratings, has the advantages of high spectral resolution, high throughput and robustness. The principle of LASHIS and its spectral retrieval method are introduced. The processing chain to convert raw images to ultraspectral datacube is also described. Experimental results demonstrate the high resolving power of LASHIS with the emission spectrum of a low pressure sodium lamp.

  19. Infrared hyperspectral upconversion imaging using spatial object translation.

    PubMed

    Kehlet, Louis Martinus; Sanders, Nicolai; Tidemand-Lichtenberg, Peter; Dam, Jeppe Seidelin; Pedersen, Christian

    2015-12-28

    In this paper hyperspectral imaging in the mid-infrared wavelength region is realised using nonlinear frequency upconversion. The infrared light is converted to the near-infrared region for detection with a Si-based CCD camera. The object is translated in a predefined grid by motorized actuators and an image is recorded for each position. A sequence of such images is post-processed into a series of monochromatic images in a wavelength range defined by the phasematch condition and numerical aperture of the upconversion system. A standard USAF resolution target and a polystyrene film are used to impart spatial and spectral information unto the source. PMID:26832059

  20. Assessing the spatial fidelity of resolution-enhanced imagery using Fourier analysis: a proof-of-concept study

    NASA Astrophysics Data System (ADS)

    Civco, Daniel L.; Witharana, Chandi

    2012-10-01

    Pan-sharpening of moderate resolution multispectral remote sensing data with those of a higher spatial resolution is a standard practice in remote sensing image processing. This paper suggests a method by which the spatial properties of resolution merge products can be assessed. Whereas there are several accepted metrics, such as correlation and root mean square error, for quantifying the spectral integrity of fused images, relative to the original multispectral data, there is less agreement on a means by which to assess the spatial properties, relative to the original higher-resolution, pansharpening data. In addition to qualitative, visual, and somewhat subjective evaluation, quantitative measures used have included correlations between high-pass filtered panchromatic and fused images, gradient analysis, wavelet analysis, among others. None of these methods, however, fully exploits the spatial and structural information contained in the original high resolution and fused images. This paper proposes the use of the Fourier transform as a means to quantify the degree to which a fused image preserves the spatial properties of the pan-sharpening high resolution data. A highresolution 8-bit panchromatic image was altered to produce a set of nine different test images, as well as a random image. The Fourier Magnitude (FM) image was calculated for each of the datasets and compared via FM to FM image correlation. Furthermore, the following edge detection algorithms were applied to the original and altered images: (a) Canny; (b) Sobel; and (c) Laplacian. These edge-filtered images were compared, again by way of correlation, with the original edge-filtered panchromatic image. Results indicate that the proposed method of using FTMI as a means of assessing the spatial fidelity of high-resolution imagery used in the data fusion process outperforms the correlations produced by way of comparing edge-enhanced images.

  1. Spatial and spectral performance of a chromotomosynthetic hyperspectral imaging system.

    PubMed

    Bostick, Randall L; Perram, Glen P

    2012-03-01

    The spatial and spectral resolutions achievable by a prototype rotating prism chromotomosynthetic imaging (CTI) system operating in the visible spectrum are described. The instrument creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a point-like target show that performance is limited by chromatic aberration. The system model is slightly inaccurate due to poor estimation of detector spatial resolution, this is corrected based on results improving model performance. As with traditional dispersion technology, calibration of the transformed wavelength axis is required, though with this technology calibration improves both spectral and spatial resolution. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz. PMID:22462909

  2. Spatial and spectral performance of a chromotomosynthetic hyperspectral imaging system

    NASA Astrophysics Data System (ADS)

    Bostick, Randall L.; Perram, Glen P.

    2012-03-01

    The spatial and spectral resolutions achievable by a prototype rotating prism chromotomosynthetic imaging (CTI) system operating in the visible spectrum are described. The instrument creates hyperspectral imagery by collecting a set of 2D images with each spectrally projected at a different rotation angle of the prism. Mathematical reconstruction techniques that have been well tested in the field of medical physics are used to reconstruct the data to produce the 3D hyperspectral image. The instrument operates with a 100 mm focusing lens in the spectral range of 400-900 nm with a field of view of 71.6 mrad and angular resolution of 0.8-1.6 μrad. The spectral resolution is 0.6 nm at the shortest wavelengths, degrading to over 10 nm at the longest wavelengths. Measurements using a point-like target show that performance is limited by chromatic aberration. The system model is slightly inaccurate due to poor estimation of detector spatial resolution, this is corrected based on results improving model performance. As with traditional dispersion technology, calibration of the transformed wavelength axis is required, though with this technology calibration improves both spectral and spatial resolution. While this prototype does not operate at high speeds, components exist which will allow for CTI systems to generate hyperspectral video imagery at rates greater than 100 Hz.

  3. The French proposal for a high spatial resolution Hyperspectral mission

    NASA Astrophysics Data System (ADS)

    Carrère, Véronique; Briottet, Xavier; Jacquemoud, Stéphane; Marion, Rodolphe; Bourguignon, Anne; Chami, Malik; Chanussot, Jocelyn; Chevrel, Stéphane; Deliot, Philippe; Dumont, Marie; Foucher, Pierre-Yves; Gomez, Cécile; Roman-Minghelli, Audrey; Sheeren, David; Weber, Christiane; Lefèvre, Marie-José; Mandea, Mioara

    2014-05-01

    More than 25 years of airborne imaging spectroscopy and spaceborne sensors such as Hyperion or HICO have clearly demonstrated the ability of such a remote sensing technique to produce value added information regarding surface composition and physical properties for a large variety of applications. Scheduled missions such as EnMAP and PRISMA prove the increased interest of the scientific community for such a type of remote sensing data. In France, a group of Science and Defence users of imaging spectrometry data (Groupe de Synthèse Hyperspectral, GSH) established an up-to-date review of possible applications, define instrument specifications required for accurate, quantitative retrieval of diagnostic parameters, and identify fields of application where imaging spectrometry is a major contribution. From these conclusions, CNES (French Space Agency) decided a phase 0 study for an hyperspectral mission concept, named at this time HYPXIM (HYPerspectral-X IMagery), the main fields of applications are vegetation biodiversity, coastal and inland waters, geosciences, urban environment, atmospheric sciences, cryosphere and Defence. Results pointed out applications where high spatial resolution was necessary and would not be covered by the other foreseen hyperspectral missions. The phase A started at the beginning of 2013 based on the following HYPXIM characteristics: a hyperspectral camera covering the [0.4 - 2.5 µm] spectral range with a 8 m ground sampling distance (GSD) and a PAN camera with a 1.85 m GSD, onboard a mini-satellite platform. This phase A is currently stopped due to budget constraints. Nevertheless, the Science team is currently focusing on the preparation for the next CNES prospective meeting (March, 2014), an important step for the future of the mission. This paper will provide an update of the status of this mission and of new results obtained by the Science team.

  4. SU-D-9A-02: Relative Effects of Threshold Choice and Spatial Resolution Modeling On SUV and Volume Quantification in F18-FDG PET Imaging of Anal Cancer Patients

    SciTech Connect

    Zhao, F; Bowsher, J; Palta, M; Czito, B; Willett, C; Yin, F

    2014-06-01

    Purpose: PET imaging with F18-FDG is utilized for treatment planning, treatment assessment, and prognosis. A region of interest (ROI) encompassing the tumor may be determined on the PET image, often by a threshold T on the PET standard uptake values (SUVs). Several studies have shown prognostic value for relevant ROI properties including maximum SUV value (SUVmax), metabolic tumor volume (MTV), and total glycolytic activity (TGA). The choice of threshold T may affect mean SUV value (SUVmean), MTV, and TGA. Recently spatial resolution modeling (SRM) has been introduced on many PET systems. SRM may also affect these ROI properties. The purpose of this work is to investigate the relative influence of SRM and threshold choice T on SUVmean, MTV, TGA, and SUVmax. Methods: For 9 anal cancer patients, 18F-FDG PET scans were performed prior to treatment. PET images were reconstructed by 2 iterations of Ordered Subsets Expectation Maximization (OSEM), with and without SRM. ROI contours were generated by 5 different SUV threshold values T: 2.5, 3.0, 30%, 40%, and 50% of SUVmax. Paired-samples t tests were used to compare SUVmean, MTV, and TGA (a) for SRM on versus off and (b) between each pair of threshold values T. SUVmax was also compared for SRM on versus off. Results: For almost all (57/60) comparisons of 2 different threshold values, SUVmean, MTV, and TGA showed statistically significant variation. For comparison of SRM on versus off, there were no statistically significant changes in SUVmax and TGA, but there were statistically significant changes in MTV for T=2.5 and T=3.0 and in SUVmean for all T. Conclusion: The near-universal statistical significance of threshold choice T suggests that, regarding harmonization across sites, threshold choice may be a greater concern than choice of SRM. However, broader study is warranted, e.g. other iterations of OSEM should be considered.

  5. High spatial resolution measurements of ram accelerator gas dynamic phenomena

    NASA Technical Reports Server (NTRS)

    Hinkey, J. B.; Burnham, E. A.; Bruckner, A. P.

    1992-01-01

    High spatial resolution experimental tube wall pressure measurements of ram accelerator gas dynamic phenomena are presented. The projectile resembles the centerbody of a ramjet and travels supersonically through a tube filled with a combustible gaseous mixture, with the tube acting as the outer cowling. Pressure data are recorded as the projectile passes by sensors mounted in the tube wall at various locations along the tube. Data obtained by using a special highly instrumented section of tube has allowed the recording of gas dynamic phenomena with a spatial resolution on the order of one tenth the projectile length. High spatial resolution tube wall pressure data from the three regimes of propulsion studied to date (subdetonative, transdetonative, and superdetonative) are presented and reveal the 3D character of the flowfield induced by projectile fins and the canting of the projectile body relative to the tube wall. Also presented for comparison to the experimental data are calculations made with an inviscid, 3D CFD code.

  6. 3-dimensional imaging at nanometer resolutions

    DOEpatents

    Werner, James H.; Goodwin, Peter M.; Shreve, Andrew P.

    2010-03-09

    An apparatus and method for enabling precise, 3-dimensional, photoactivation localization microscopy (PALM) using selective, two-photon activation of fluorophores in a single z-slice of a sample in cooperation with time-gated imaging for reducing the background radiation from other image planes to levels suitable for single-molecule detection and spatial location, are described.

  7. Implementation of soft x-ray microscopy with several tens nanometers spatial resolution at NSRL

    NASA Astrophysics Data System (ADS)

    Jiang, Shiping; Chen, Liang

    2009-09-01

    A transmission soft x-ray microscope (TXM), which is similar to the full-field x-ray microscopes installed on other synchrotron radiation sources in the world, was developed at National Synchrotron Radiation Laboratory (NSRL) in Hefei. An x-ray image taken with the microscope was acquired and its spatial resolution was estimated to be better than 70nm.

  8. Using High Spatial Resolution to Improve BOLD fMRI Detection at 3T

    PubMed Central

    Claise, Béatrice; Jean, Betty

    2015-01-01

    For different functional magnetic resonance imaging experiments using blood oxygenation level-dependent (BOLD) contrast, the acquisition of T2*-weighted scans at a high spatial resolution may be advantageous in terms of time-course signal-to-noise ratio and of BOLD sensitivity when the regions are prone to susceptibility artifacts. In this study, we explore this solution by examining how spatial resolution influences activations elicited when appetizing food pictures are viewed. Twenty subjects were imaged at 3 T with two different voxel volumes, 3.4 μl and 27 μl. Despite the diminution of brain coverage, we found that high-resolution acquisition led to a better detection of activations. Though known to suffer to different degrees from susceptibility artifacts, the activations detected by high spatial resolution were notably consistent with those reported in published activation likelihood estimation meta-analyses, corresponding to taste-responsive regions. Furthermore, these regions were found activated bilaterally, in contrast with previous findings. Both the reduction of partial volume effect, which improves BOLD contrast, and the mitigation of susceptibility artifact, which boosts the signal to noise ratio in certain regions, explained the better detection noted with high resolution. The present study provides further evidences that high spatial resolution is a valuable solution for human BOLD fMRI, especially for studying food-related stimuli. PMID:26550990

  9. Improved Spatial Resolution For Reflection Mode Infrared Spectromicroscopy

    SciTech Connect

    Bechtel, Hans A; Martin, Michael C.; May, T. E.; Lerch, Philippe

    2009-08-13

    Standard commercial infrared microscopes operating in reflection mode use a mirror to direct the reflected light from the sample to the detector. This mirror blocks about half of the incident light, however, and thus degrades the spatial resolution by reducing the numerical aperture of the objective. Here, we replace the mirror with a 50% beamsplitter to allow full illumination of the objective and retain a way to direct the reflected light to the detector. The improved spatial resolution is demonstrated using a microscope coupled to a synchrotron source.

  10. Resolution in digital imaging: enough already?

    PubMed

    Siegel, Daniel Mark

    2002-09-01

    Digital images have become the new currency for the exchange of information in dermatology. The main value of the digital image, its ability to be transported via the Internet, is optimal if the image can be shared by all interested parties without the need for the still relatively uncommon broadband connection. The technology behind these captured images is progressing rapidly with a resultant increase in image size and resolution. For all practical purposes in clinical dermatology, the current technology with regard to resolution has already gone beyond the needs of the clinician. This article, using freeware and commercially used software, offers proof that a single megapixel image is adequate for on screen evaluation and publication purposes. PMID:12322995

  11. Image Resolution in Scanning Transmission Electron Microscopy

    SciTech Connect

    Pennycook, S. J.; Lupini, A.R.

    2008-06-26

    Digital images captured with electron microscopes are corrupted by two fundamental effects: shot noise resulting from electron counting statistics and blur resulting from the nonzero width of the focused electron beam. The generic problem of computationally undoing these effects is called image reconstruction and for decades has proved to be one of the most challenging and important problems in imaging science. This proposal concerned the application of the Pixon method, the highest-performance image-reconstruction algorithm yet devised, to the enhancement of images obtained from the highest-resolution electron microscopes in the world, now in operation at Oak Ridge National Laboratory.

  12. Spatial compound imaging for fiber-bundle optic microscopy

    NASA Astrophysics Data System (ADS)

    Cheon, Gyeong Woo; Cha, Jaepyeong; Kang, Jin U.

    2014-02-01

    Coherent fiber bundles with high core density give both flexibility and high resolution to microscopy. Despite of these advantages, fiber bundles inevitably have uncovered region between adjacent cores. The region results in structural artifact known as pixelation effect. Many kinds of image processing techniques have been introduced to remove this pixelation artifact such as frequency domain filter and Gaussian filter. However, these methods fundamentally have limitation because they use the information of adjacent pixels to make up for these uncovered area; therefore, they cannot avoid blurring effect as a result. To overcome this problem, we introduce spatial compound imaging method to overcome this pixelation artifact. The method uses multiple frames taken with small deviation of position. Some parts of these images include information which is devoid of in other images. The total amount of information increase as more images are added up and we can expect the improvement of resolution in the final images. At the same time, the duplicated parts among these images can be averaged to improve SNR ratio. For these improvements, we essentially need sophisticated registration algorithm. The pixelation artifact is troublesome again in registration process because its structural artifacts are strong features shared with whole images. However, we can solve this problem by using reference image and divide the sample images into two parts: effective and ineffective regions. We used effective regions for registration. We used USAF target to evaluate our method and we could get a result that SNR and resolution are both critically increase.

  13. Super resolution imaging and nanoscale magnetic detection in microfluidic device

    NASA Astrophysics Data System (ADS)

    Lim, Kangmook

    Nanoscale sensing and imaging tools are the most emerging techniques in fields of nanoscience research and engineering. To demonstrate nanoscale sensing and imaging tools, it is required to achieve high sensitivity and spatial resolution simultaneously. By fulfilling the requirements, this thesis describes mainly two different scanning applications employing quantum probes and nanoparticle positioning technique using fluid flow control. First, we develop a method that can systematically probe the distortion of an emitter's diffraction spot near a nanoparticle in a microfluidic device. The results provide a better fundamental understanding of near-field coupling between emitters and nanophotonic structures. We demonstrate that by monitoring the distortion of the diffraction spot we can perform highly accurate imaging of the nanoparticle with 8 nm spatial precision. Next, we develop a method to perform localized magnetometry in a microfluidic device with a 48 nm spatial precision. We map out the local field distribution of a magnetic nanoparticle by manipulating it in the vicinity of an immobilized single NV center and optically detecting the induced Zeeman shift with a magnetic field sensitivity of 17.5 muT Hz-1/2. Finally, we introduce a scanning magnetic field technique that employs multiple NV centers in diamond nanocrystals suspended in microfluidic channels. This technique has advantages of short acquisition time over wide-field with nanoscale spatial resolution. The advantages make our technique attractive to a wide range of magnetic imaging applications in fluidic environments and biophysical systems.

  14. Resolution enhancement in medical ultrasound imaging

    PubMed Central

    Ploquin, Marie; Basarab, Adrian; Kouamé, Denis

    2015-01-01

    Abstract. Image resolution enhancement is a problem of considerable interest in all medical imaging modalities. Unlike general purpose imaging or video processing, for a very long time, medical image resolution enhancement has been based on optimization of the imaging devices. Although some recent works purport to deal with image postprocessing, much remains to be done regarding medical image enhancement via postprocessing, especially in ultrasound imaging. We face a resolution improvement issue in the case of medical ultrasound imaging. We propose to investigate this problem using multidimensional autoregressive (AR) models. Noting that the estimation of the envelope of an ultrasound radio frequency (RF) signal is very similar to the estimation of classical Fourier-based power spectrum estimation, we theoretically show that a domain change and a multidimensional AR model can be used to achieve super-resolution in ultrasound imaging provided the order is estimated correctly. Here, this is done by means of a technique that simultaneously estimates the order and the parameters of a multidimensional model using relevant regression matrix factorization. Doing so, the proposed method specifically fits ultrasound imaging and provides an estimated envelope. Moreover, an expression that links the theoretical image resolution to both the image acquisition features (such as the point spread function) and a postprocessing feature (the AR model) order is derived. The overall contribution of this work is threefold. First, it allows for automatic resolution improvement. Through a simple model and without any specific manual algorithmic parameter tuning, as is used in common methods, the proposed technique simply and exclusively uses the ultrasound RF signal as input and provides the improved B-mode as output. Second, it allows for the a priori prediction of the improvement in resolution via the knowledge of the parametric model order before actual processing. Finally, to achieve

  15. Spatial resolution attainable in germanium detectors by pulse shape analysis

    SciTech Connect

    Blair, J., Bechtel, NV; Beckedahl, D.; Kammeraad, J.; Schmid, G., LLNL

    1998-05-01

    There are several applications for which it is desirable to calculate the locations and energies of individual gamma-ray interactions within a high purity germanium (HPGe) detector. These include gamma-ray imaging and Compton suppression. With a segmented detector this can be accomplished by analyzing the pulse shapes of the signals from the various segments. We examine the fundamental limits to the spatial resolution attainable with this approach. The primary source of error is the series noise of the field effect transistors (FETs) at the inputs of the charge amplifiers. We show how to calculate the noise spectral density at the output of the charge amplifiers due to an optimally selected FET. This calculation is based only on the detector capacitance and a noise constant for the FET technology. We show how to use this spectral density to calculate the uncertainties in parameters, such as interaction locations and energies, that are derived from pulse shape analysis using maximum likelihood estimation (MLE) applied to filtered and digitized recordings of the charge signals. Example calculations are given to illustrate our approach. Experimental results are given that demonstrate that one can construct complete systems, from detector through data analysis, that come near the theoretical limits.

  16. High spatial resolution spectrometry of rafting macroalgae (Sargassum)

    NASA Astrophysics Data System (ADS)

    Szekielda, Karl H.; Marmorino, George O.; Bowles, Jeffrey H.; Gillis, David

    2010-04-01

    Data with 0.4-m spatial resolution acquired ~2 km off the southeast Florida coast using the airborne Portable Hyperspectral Imager for Low-Light Spectroscopy (PHILLS) have been analyzed with the objective of identifying drifting surface macroalgae (Sargassum) through its spectral signature in at-sensor radiance. The observed spectral features of Sargassum include a peak at a wavelength of ~0.570 μm and a photosynthetic 'red edge' between 0.673 and 0.699 μm. Sargassum also exhibits high radiance in the reflected near-infrared but is impacted by the atmospheric absorption bands of water vapor at 0.720 μm and oxygen at 0.756 μm. The spectral signature is clearest and largest in amplitude where the Sargassum occurs as small surface aggregations, or rafts, which tend to lie at the downwind ends of narrow Sargassum windrows. The quantity of floating Sargassum was estimated within a single pixel by linearly mixing a spectrum of Sargassum-free water with varying percentages of a spectrum from a pixel assumed completely filled with floating plants. For our study site about 2.3% of the ocean area is classified as having some Sargassum coverage, with pixels completely filled with Sargassum being rare (only 0.2% of the classified Sargassum pixels) and pixels with the least-resolvable amount of Sargassum (~10% filled) being the most common.

  17. Estimation of Orbital Neutron Detector Spatial Resolution by Systematic Shifting of Differential Topographic Masks

    NASA Technical Reports Server (NTRS)

    McClanahan, T. P.; Mitrofanov, I. G.; Boynton, W. V.; Chin, G.; Livengood, T.; Starr, R. D.; Evans, L. G.; Mazarico, E.; Smith, D. E.

    2012-01-01

    We present a method and preliminary results related to determining the spatial resolution of orbital neutron detectors using epithermal maps and differential topographic masks. Our technique is similar to coded aperture imaging methods for optimizing photonic signals in telescopes [I]. In that approach photon masks with known spatial patterns in a telescope aperature are used to systematically restrict incoming photons which minimizes interference and enhances photon signal to noise. Three orbital neutron detector systems with different stated spatial resolutions are evaluated. The differing spatial resolutions arise due different orbital altitudes and the use of neutron collimation techniques. 1) The uncollimated Lunar Prospector Neutron Spectrometer (LPNS) system has spatial resolution of 45km FWHM from approx. 30km altitude mission phase [2]. The Lunar Rennaissance Orbiter (LRO) Lunar Exploration Neutron Detector (LEND) with two detectors at 50km altitude evaluated here: 2) the collimated 10km FWHM spatial resolution detector CSETN and 3) LEND's collimated Sensor for Epithermal Neutrons (SETN). Thus providing two orbital altitudes to study factors of: uncollimated vs collimated and two average altitudes for their effect on fields-of-view.

  18. Dual-source parallel radiofrequency excitation ACR phantom magnetic resonance imaging at 3 T: Assessment of the effect of image quality on high-contrast spatial resolution, percent signal ghosting, and low-contrast object detectability in comparison with conventional single-source transmission

    NASA Astrophysics Data System (ADS)

    Lee, Kyung-Bae; Park, Yong-Sung; Choe, Bo-Young

    2013-10-01

    The purpose of the present study was to assess dual-source parallel radiofrequency (RF) excitation American College of Radiology (ACR) phantom magnetic resonance (MR) imaging at 3T compared with conventional single-source RF transmission and compared with the standard ACR MRI phantom test. We used a 3T MR scanner equipped with dual-source parallel RF excitation and an 8-channel head phased array coil. We employed T1- and T2-weighted fast spin echo (FSE) pulse sequences for an assessment of the impact of image quality on high-contrast spatial resolution, percent signal ghosting and low-contrast object detectability following the ACR MRI quality control (QC) manual. With geometric accuracy and identical slice locations, dual RFs using dual-source parallel RF excitation MR showed an advantage over single RF using dual-source parallel RF excitation MR and conventional MR in terms of high-contrast spatial resolution (p < 0.010), percent signal ghosting (p < 0.010), and low-contrast object detectability (p < 0.010). The quality of the image from the dual-source parallel RF excitation MR equipment was superior to that of the image from conventional MR equipment for the ACR phantom. We need to pursue dual-source parallel RF excitation MR studies involving various clinical cases.

  19. High-resolution dynamic speech imaging with deformation estimation.

    PubMed

    Maojing Fu; Barlaz, Marissa S; Shosted, Ryan K; Zhi-Pei Liang; Sutton, Bradley P

    2015-08-01

    Dynamic speech magnetic resonance imaging (DSMRI) is a promising technique for visualizing articulatory motion in real time. However, many existing applications of DSMRI have been limited by slow imaging speed and the lack of quantitative motion analysis. In this paper, we present a novel DS-MRI technique to simultaneously estimate dynamic image sequence of speech and the associated deformation field. Extending on our previous Partial Separability (PS) model-based methods, the proposed technique visualizes both speech motion and deformation with a spatial resolution of 2.2 × 2.2 mm(2) and a nominal frame rate of 100 fps. Also, the technique enables direct analysis of articulatory motion through the deformation fields. Effectiveness of the method is systematically examined via in vivo experiments. Utilizing the obtained high-resolution images and deformation fields, we also performed a phonetics study on Brazilian Portuguese to show the method's practical utility. PMID:26736572

  20. Explore spatial-temporal relations: transient super-resolution with PMD sensors

    NASA Astrophysics Data System (ADS)

    Han, Chaosheng; Lin, Xing; Lin, Jingyu; Yan, Chenggang; Dai, Qionghai

    2014-11-01

    Transient imaging provides a direct view of how light travel in the scene, which leads to exciting applications such as looking around corners. Low-budget transient imagers, adapted from Time-of-Fight (ToF) cameras, reduce the barrier of entry for performing research of this new imaging modality. However, the image quality is far from satisfactory due to the limited resolution of PMD sensors. In this paper, we improve the resolution of transient images by modulating the illumination. We capture the scene under three linearly independent lighting conditions, and derive a theoretical model for the relationship between the time-profile and the corresponding 3D details of each pixel. Our key idea is that the light flight time in each pixel patch is proportional to the cross product of the illuminating direction and the surface normal. First we capture and reconstruct transient images by Fourier analysis at multiple illumination locations, and then fuse the data of acquired low-spatial resolution images to calculate the surface normal. Afterwards, we use an optimization procedure to split the pixels and finally enhance the image quality. We show that we can not only reveal the fine structure of the object but may also uncover the reflectance properties of different materials. We hope the idea of utilizing spatial-temporal relations will give new insights to the research and applications of transient imaging.

  1. Freehand spatial-angular compounding of photoacoustic images

    NASA Astrophysics Data System (ADS)

    Kang, Hyun-Jae; Lediju Bell, Muyinatu A.; Guo, Xiaoyu; Taylor, Russell H.; Boctor, Emad M.

    2014-03-01

    Photoacoustic (PA) imaging is an emerging medical imaging modality that relies on the absorption of optical energy and the subsequent emission of acoustic waves that are detected with a conventional ultrasound probe. PA images are susceptible to background noise artifacts that reduce the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR). We investigated spatial-angular compounding of PA images to enhance these image qualities. Spatial-angular compounding was implemented by averaging multiple PA images acquired as an ultrasound probe was rotated about the elevational axis with the laser beam and PA target fixed in the same location. An external tracking system was used to provide the position and orientation (i.e. pose) information of each PA image. Based on this pose information, frames in similar elevational planes were filtered from the acquired image data and compounded using one of two methods. One method registered overlapping signals between frames prior to compounding (using the pose information), while the second method omitted this spatial registration step. These two methods were applied to pre-beamformed RF, beamformed RF, and envelope-detected data, resulting in six different compounding pipelines. Compounded PA images with similar lateral resolution to a single reference image had factors of 1.1 - 1.6, 2.0 - 11.1, and 2.0 - 11.1 improvements in contrast, CNR, and SNR, respectively, when compared to the reference image. These improvements depended on the amount of relative motion between the reference image and the images that were compounded. The inclusion of spatial registration prior to compounding preserved lateral resolution and signal location when the relative rotations about the elevation axis were 3.5° or less for images that were within an elevational distance of 2.5 mm from the reference image, particularly when the method was applied to the enveloped-detected data. Results indicate that spatial-angular compounding has the

  2. Super-resolution images fusion via compressed sensing and low-rank matrix decomposition

    NASA Astrophysics Data System (ADS)

    Ren, Kan; Xu, Fuyuan

    2015-01-01

    Most of available image fusion approaches cannot achieve higher spatial resolution than the multisource images. In this paper we propose a novel simultaneous images super-resolution and fusion approach via the recently developed compressed sensing and multiscale dictionaries learning technology. Under the sparse prior of image patches and the framework of compressed sensing, multisource images fusion is reduced to a task of signal recovery from the compressive measurements. Then a set of multiscale dictionaries are learned from some groups of example high-resolution (HR) image patches via a nonlinear optimization algorithm. Moreover, a linear weights fusion rule is advanced to obtain the fused high-resolution image at each scale. Finally the high-resolution image is derived by performing a low-rank decomposition on the recovered high-resolution images at multiple scales. Some experiments are taken to investigate the performance of our proposed method, and the results prove its superiority to the counterparts.

  3. ADVANCED IMAGING. Extended-resolution structured illumination imaging of endocytic and cytoskeletal dynamics.

    PubMed

    Li, Dong; Shao, Lin; Chen, Bi-Chang; Zhang, Xi; Zhang, Mingshu; Moses, Brian; Milkie, Daniel E; Beach, Jordan R; Hammer, John A; Pasham, Mithun; Kirchhausen, Tomas; Baird, Michelle A; Davidson, Michael W; Xu, Pingyong; Betzig, Eric

    2015-08-28

    Super-resolution fluorescence microscopy is distinct among nanoscale imaging tools in its ability to image protein dynamics in living cells. Structured illumination microscopy (SIM) stands out in this regard because of its high speed and low illumination intensities, but typically offers only a twofold resolution gain. We extended the resolution of live-cell SIM through two approaches: ultrahigh numerical aperture SIM at 84-nanometer lateral resolution for more than 100 multicolor frames, and nonlinear SIM with patterned activation at 45- to 62-nanometer resolution for approximately 20 to 40 frames. We applied these approaches to image dynamics near the plasma membrane of spatially resolved assemblies of clathrin and caveolin, Rab5a in early endosomes, and α-actinin, often in relationship to cortical actin. In addition, we examined mitochondria, actin, and the Golgi apparatus dynamics in three dimensions. PMID:26315442

  4. High-resolution microchannel plate image tube results

    NASA Astrophysics Data System (ADS)

    Johnson, C. Bruce; Patton, Stanley B.; Bender, E.

    1992-07-01

    The present 18-mm active diameter proximity-focused microchannel plate (MCP) image tube design has been modified to produce significantly higher limiting spatial resolution. A glass input window of the `bulls-eye' design with the blackened glass border, reduced cathode-to-MCP spacing, reduced channel center-to-center distance, reduced MCP-to-phosphor screen spacing, a brushed P20 phosphor screen, and a fiber optic output window were used to achieve a limiting resolution in excess of 50 lp/mm. Test results, showing limiting resolution versus applied potentials, are correlated with a simple physical model of performance. The low-light-level white-light sine-wave modulation transfer function, T(f), has been measured to be T(f) equals exp[-(f/21.5)1.46], where f is the spatial frequency in cycles per millimeter.

  5. Effect of spatial resolution of radar-based inundation maps on the calibration of a spatial inundation model

    NASA Astrophysics Data System (ADS)

    Gobeyn, Sacha; Vernieuwe, Hilde; De Baets, Bernard; Bates, Paul; Verhoest Niko E., C.

    2013-04-01

    With advances in both flood mapping with satellite radar and computational science, the use of real-time spatial flood data holds the potential to support decision making during flood events. With recent improvements in satellite radar technology, current and future radar images are/will be delivered with higher spatial resolution. It is expected that these higher resolutions should improve the accuracy of the calibration and the prediction through data assimilation as more detailed information is available. However, these finer resolution data will result in an increased computational cost. Still, radar data of coarser resolution will remain available, and the question may then arise whether the calibration of a 2D-hydraulic model is significantly influenced by the resolution of the remotely-sensed inundation map. In order to answer this question, the raster-based inundation model, LISFLOOD-FP (Bates et al., 2000) is calibrated using a high resolution synthetic aperture radar image (ERS-2 SAR) of a flood event of the river Dee, Wales, in December 2006. Different radar resolutions are simulated through coarsening this image to different resolutions and retrieving the flood extent maps for the different resolutions. These flood maps are then used for calibrating the hydraulic model using the generalized likelihood uncertainty estimation (GLUE) framework presented by Aronica et al. (2002) as well as alternative calibration methods (e.g. Particle Swarm Optimization, PSO) to assess the possible impact of spatial resolution of the observed flood extent on the floodplain and channel Manning coefficient. Furthermore, the sensitivity of the calibration surface to error sources in radar measurement is evaluated by applying different magnitudes of noise to the radar image. References Aronica, G., Bates, P. D. and Horritt, M. S. (2002). Assessing the uncertainty in distributed model predictions using observed binary pattern information within GLUE. Hydrological Processes, 16

  6. [Fundamental study of helical scanning CT--evaluation of spatial resolution in the longitudinal axis].

    PubMed

    Anno, H; Katada, K; Tsujioka, K; Ida, Y; Ohashi, I; Takeuchi, A; Koga, S

    1992-11-25

    We evaluated spatial resolution in the longitudinal axis with helical scanning CT using a fourth-generation fast CT scanner. We made a phantom by stringing acrylic balls (65 mm phi x 8 and 9 mm phi x 6). The acquired images were processed by MPR and assessed visually to evaluate axis resolution. With the conventional scanning method, the partial volume effect varied with the starting position, but helical scanning was able to reconstruct high-resolution images using continuous raw data. During helical scanning, axis resolution varied depending on the slice width and sliding speed of the couch top. Even if the sliding speed was kept constant at 4 mm/sec, axis resolution was superior with a slice width of 2 mm than with one of 5 mm. PMID:1465334

  7. Spatial-scanning hyperspectral imaging probe for bio-imaging applications

    NASA Astrophysics Data System (ADS)

    Lim, Hoong-Ta; Murukeshan, Vadakke Matham

    2016-03-01

    The three common methods to perform hyperspectral imaging are the spatial-scanning, spectral-scanning, and snapshot methods. However, only the spectral-scanning and snapshot methods have been configured to a hyperspectral imaging probe as of today. This paper presents a spatial-scanning (pushbroom) hyperspectral imaging probe, which is realized by integrating a pushbroom hyperspectral imager with an imaging probe. The proposed hyperspectral imaging probe can also function as an endoscopic probe by integrating a custom fabricated image fiber bundle unit. The imaging probe is configured by incorporating a gradient-index lens at the end face of an image fiber bundle that consists of about 50 000 individual fiberlets. The necessary simulations, methodology, and detailed instrumentation aspects that are carried out are explained followed by assessing the developed probe's performance. Resolution test targets such as United States Air Force chart as well as bio-samples such as chicken breast tissue with blood clot are used as test samples for resolution analysis and for performance validation. This system is built on a pushbroom hyperspectral imaging system with a video camera and has the advantage of acquiring information from a large number of spectral bands with selectable region of interest. The advantages of this spatial-scanning hyperspectral imaging probe can be extended to test samples or tissues residing in regions that are difficult to access with potential diagnostic bio-imaging applications.

  8. Resolution and quantitative accuracy improvements in ultrasound transmission imaging

    NASA Astrophysics Data System (ADS)

    Chenevert, T. L.

    The type of ultrasound transmission imaging, referred to as ultrasonic computed tomography (UCT), reconstructs distributions of tissue speed of sound and sound attenuation properties from measurements of acoustic pulse time of flight (TCF) and energy received through tissue. Although clinical studies with experimental UCT scanners have demonstrated UCT is sensitive to certain tissue pathologies not easily detected with conventional ultrasound imaging, they have also shown UCT to suffer from artifacts due to physical differences between the acoustic beam and its ray model implicit in image reconstruction algorithms. Artifacts are expressed as large quantitative errors in attenuation images, and poor spatial resolution and size distortion (exaggerated size of high speed of sound regions) in speed of sound images. Methods are introduced and investigated which alleviate these problems in UCT imaging by providing improved measurements of pulse TCF and energy.

  9. Decoding Rich Spatial Information with High Temporal Resolution

    PubMed Central

    Stokes, Mark G.; Wolff, Michael J.; Spaak, Eelke

    2015-01-01

    New research suggests that magnetoencephalography (MEG) contains rich spatial information for decoding neural states. Even small differences in the angle of neighbouring dipoles generate subtle, but statistically separable field patterns. This implies MEG (and electroencephalography: EEG) is ideal for decoding neural states with high-temporal resolution in the human brain. PMID:26440122

  10. Imaging flow cytometer using computation and spatially coded filter

    NASA Astrophysics Data System (ADS)

    Han, Yuanyuan; Lo, Yu-Hwa

    2016-03-01

    Flow cytometry analyzes multiple physical characteristics of a large population of single cells as cells flow in a fluid stream through an excitation light beam. Flow cytometers measure fluorescence and light scattering from which information about the biological and physical properties of individual cells are obtained. Although flow cytometers have massive statistical power due to their single cell resolution and high throughput, they produce no information about cell morphology or spatial resolution offered by microscopy, which is a much wanted feature missing in almost all flow cytometers. In this paper, we invent a method of spatial-temporal transformation to provide flow cytometers with cell imaging capabilities. The method uses mathematical algorithms and a specially designed spatial filter as the only hardware needed to give flow cytometers imaging capabilities. Instead of CCDs or any megapixel cameras found in any imaging systems, we obtain high quality image of fast moving cells in a flow cytometer using photomultiplier tube (PMT) detectors, thus obtaining high throughput in manners fully compatible with existing cytometers. In fact our approach can be applied to retrofit traditional flow cytometers to become imaging flow cytometers at a minimum cost. To prove the concept, we demonstrate cell imaging for cells travelling at a velocity of 0.2 m/s in a microfluidic channel, corresponding to a throughput of approximately 1,000 cells per second.

  11. Image reconstructions from super-sampled data sets with resolution modeling in PET imaging

    PubMed Central

    Li, Yusheng; Matej, Samuel; Metzler, Scott D.

    2014-01-01

    Purpose: Spatial resolution in positron emission tomography (PET) is still a limiting factor in many imaging applications. To improve the spatial resolution for an existing scanner with fixed crystal sizes, mechanical movements such as scanner wobbling and object shifting have been considered for PET systems. Multiple acquisitions from different positions can provide complementary information and increased spatial sampling. The objective of this paper is to explore an efficient and useful reconstruction framework to reconstruct super-resolution images from super-sampled low-resolution data sets. Methods: The authors introduce a super-sampling data acquisition model based on the physical processes with tomographic, downsampling, and shifting matrices as its building blocks. Based on the model, we extend the MLEM and Landweber algorithms to reconstruct images from super-sampled data sets. The authors also derive a backprojection-filtration-like (BPF-like) method for the super-sampling reconstruction. Furthermore, they explore variant methods for super-sampling reconstructions: the separate super-sampling resolution-modeling reconstruction and the reconstruction without downsampling to further improve image quality at the cost of more computation. The authors use simulated reconstruction of a resolution phantom to evaluate the three types of algorithms with different super-samplings at different count levels. Results: Contrast recovery coefficient (CRC) versus background variability, as an image-quality metric, is calculated at each iteration for all reconstructions. The authors observe that all three algorithms can significantly and consistently achieve increased CRCs at fixed background variability and reduce background artifacts with super-sampled data sets at the same count levels. For the same super-sampled data sets, the MLEM method achieves better image quality than the Landweber method, which in turn achieves better image quality than the BPF-like method. The

  12. Spatially Patterned Electrical Stimulation to Enhance Resolution of Retinal Prostheses

    PubMed Central

    Hottowy, Paweł; Mathieson, Keith; Gunning, Deborah E.; Dąbrowski, Władysław; Litke, Alan M.; Chichilnisky, E. J.

    2014-01-01

    Retinal prostheses electrically stimulate neurons to produce artificial vision in people blinded by photoreceptor degenerative diseases. The limited spatial resolution of current devices results in indiscriminate stimulation of interleaved cells of different types, precluding veridical reproduction of natural activity patterns in the retinal output. Here we investigate the use of spatial patterns of current injection to increase the spatial resolution of stimulation, using high-density multielectrode recording and stimulation of identified ganglion cells in isolated macaque retina. As previously shown, current passed through a single electrode typically induced a single retinal ganglion cell spike with submillisecond timing precision. Current passed simultaneously through pairs of neighboring electrodes modified the probability of activation relative to injection through a single electrode. This modification could be accurately summarized by a piecewise linear model of current summation, consistent with a simple biophysical model based on multiple sites of activation. The generalizability of the piecewise linear model was tested by using the measured responses to stimulation with two electrodes to predict responses to stimulation with three electrodes. Finally, the model provided an accurate prediction of which among a set of spatial stimulation patterns maximized selective activation of a cell while minimizing activation of a neighboring cell. The results demonstrate that tailored multielectrode stimulation patterns based on a piecewise linear model may be useful in increasing the spatial resolution of retinal prostheses. PMID:24695706

  13. Invariant high resolution optical skin imaging

    NASA Astrophysics Data System (ADS)

    Murali, Supraja; Rolland, Jannick

    2007-02-01

    Optical Coherence Microscopy (OCM) is a bio-medical low coherence interferometric imaging technique that has become a topic of active research because of its ability to provide accurate, non-invasive cross-sectional images of biological tissue with much greater resolution than the current common technique ultrasound. OCM is a derivative of Optical Coherence Tomography (OCT) that enables greater resolution imposed by the implementation of an optical confocal design involving high numerical aperture (NA) focusing in the sample. The primary setback of OCM, however is the depth dependence of the lateral resolution obtained that arises from the smaller depth of focus of the high NA beam. We propose to overcome this limitation using a dynamic focusing lens design that can achieve quasi-invariant lateral resolution up to 1.5mm depth of skin tissue.

  14. Spatial resolution of MFM measurements of penetration depth

    NASA Astrophysics Data System (ADS)

    Spanton, Eric; Luan, Lan; Kirtley, John; Moler, Kathryn

    2012-02-01

    The penetration depth and its temperature dependence are key ways to characterize superconductors. Measurements of the local Meissner response of a superconductor can determine the local penetration depth. To quantify the spatial resolution of such measurements, we seek to characterize the point spread function of magnetic force microscope (MFM) measurements of the penetration depth both numerically and experimentally. Modeling various geometries of MFM tips (pyramid, dipole, and long thin cylinder) in the presence of various geometries of spatial variation in the penetration depth (point variation, columnar defects, and planar defects or twin boundaries) shows the importance of the MFM tip geometry to achieving both excellent spatial resolution and quantitatively interpretable results. We compare these models to experimental data on pnictides and cuprates to set upper limits on the sub-micron-scale variation of the penetration depth. These results demonstrate both the feasibility and the technical challenges of submicron penetration depth mapping.

  15. Improved Spatial Resolution for Reflection Mode Infrared Microscopy

    SciTech Connect

    Bechtel, Hans A.; Martin, Michael C.; May, T.E.; Lerch, Philippe

    2009-10-09

    Standard commercial infrared microscopes operating in reflection mode use a mirror to direct the reflected light from the sample to the detector. This mirror blocks about half of the incident light, however, and thus degrades the spatial resolution by reducing the umerical aperture of the objective. Here, we replace the mirror with a 50% beamsplitter to allow full illumination of the objective and retain a way to direct the reflected light to the detector. The improved spatial resolution is demonstrated using two different microscopes apable of diffraction-limited resolution: the first microscope is coupled to a synchrotron source and utilizes a single point detector, whereas the second microscope has a standard blackbody source and uses a focal planetarray (FPA) detector.

  16. Optimal Discretization Resolution in Algebraic Image Reconstruction

    NASA Astrophysics Data System (ADS)

    Sharif, Behzad; Kamalabadi, Farzad

    2005-11-01

    In this paper, we focus on data-limited tomographic imaging problems where the underlying linear inverse problem is ill-posed. A typical regularized reconstruction algorithm uses algebraic formulation with a predetermined discretization resolution. If the selected resolution is too low, we may loose useful details of the underlying image and if it is too high, the reconstruction will be unstable and the representation will fit irrelevant features. In this work, two approaches are introduced to address this issue. The first approach is using Mallow's CL method or generalized cross-validation. For each of the two methods, a joint estimator of regularization parameter and discretization resolution is proposed and their asymptotic optimality is investigated. The second approach is a Bayesian estimator of the model order using a complexity-penalizing prior. Numerical experiments focus on a space imaging application from a set of limited-angle tomographic observations.

  17. High-resolution heavy ion track structure imaging

    NASA Astrophysics Data System (ADS)

    Laczko, G.; Dangendorf, V.; Krämer, M.; Schardt, D.; Tittelmeier, K.

    2004-12-01

    Radiation action in matter depends on the details of the spatial distribution of energy transfer events on the nanometer scale. In this contribution, we present an instrument for experimental investigation of spatial ionisation patterns of ions in matter. The experimental system is based on a time projection chamber with a parallel drift field, parallel-plate charge and light amplification layers and optical readout with an image-intensified CCD camera (OPtical Avalanche Chamber (OPAC)). The chamber is operated with low pressure gas (4-40 hPa) to achieve a resolution of down to 50 nm in tissue density. Preliminary results of measurements and simulations are presented.

  18. Resolution of electro-holographic image

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  19. Unsupervised Feature Learning for High-Resolution Satellite Image Classification

    SciTech Connect

    Cheriyadat, Anil M

    2013-01-01

    The rich data provided by high-resolution satellite imagery allow us to directly model geospatial neighborhoods by understanding their spatial and structural patterns. In this paper we explore an unsupervised feature learning approach to model geospatial neighborhoods for classification purposes. While pixel and object based classification approaches are widely used for satellite image analysis, often these approaches exploit the high-fidelity image data in a limited way. In this paper we extract low-level features to characterize the local neighborhood patterns. We exploit the unlabeled feature measurements in a novel way to learn a set of basis functions to derive new features. The derived sparse feature representation obtained by encoding the measured features in terms of the learned basis function set yields superior classification performance. We applied our technique on two challenging image datasets: ORNL dataset representing one-meter spatial resolution satellite imagery representing five land-use categories and, UCMERCED dataset consisting of 21 different categories representing sub-meter resolution overhead imagery. Our results are highly promising and, in the case of UCMERCED dataset we outperform the best results obtained for this dataset. We show that our feature extraction and learning methods are highly effective in developing a detection system that can be used to automatically scan large-scale high-resolution satellite imagery for detecting large-facility.

  20. Impact of spatial resolution on correlation between segmentation evaluation metrics and forest classification accuracy

    NASA Astrophysics Data System (ADS)

    Švab Lenarčič, Andreja; Ritlop, Klemen; Äńurić, Nataša.; Čotar, Klemen; Oštir, Krištof

    2015-10-01

    Slovenia is one of the most forested countries in Europe. Its forest management authorities need information about the forest extent and state, as their responsibility lies in forest observation and preservation. Together with appropriate geographic information system mapping methods the remotely sensed data represent essential tool for an effective and sustainable forest management. Despite the large data availability, suitable mapping methods still present big challenge in terms of their speed which is often affected by the huge amount of data. The speed of the classification method could be maximised, if each of the steps in object-based classification was automated. However, automation is hard to achieve, since segmentation requires choosing optimum parameter values for optimal classification results. This paper focuses on the analysis of segmentation and classification performance and their correlation in a range of segmentation parameter values applied in the segmentation step. In order to find out which spatial resolution is still suitable for forest classification, forest classification accuracies obtained by using four images with different spatial resolutions were compared. Results of this study indicate that all high or very high spatial resolutions are suitable for optimal forest segmentation and classification, as long as appropriate scale and merge parameters combinations are used in the object-based classification. If computation interval includes all segmentation parameter combinations, all segmentation-classification correlations are spatial resolution independent and are generally high. If computation interval includes over- or optimal-segmentation parameter combinations, most segmentation-classification correlations are spatial resolution dependent.

  1. Pyramidal fractal dimension for high resolution images

    NASA Astrophysics Data System (ADS)

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

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

  2. Pyramidal fractal dimension for high resolution images.

    PubMed

    Mayrhofer-Reinhartshuber, Michael; Ahammer, Helmut

    2016-07-01

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

  3. High-resolution ultrasound-aided biophotonic imaging.

    PubMed

    Wang, Lihong V; Wang, Xueding; Ku, Geng; Xie, Xueyi; Stoica, George

    2004-01-01

    Optical contrast is sensitive to functional parameters, including the oxygen saturation and total concentration of hemoglobin, in biological tissues. However, due to the overwhelming scattering encountered by light in tissues, traditional optical modalities cannot provide satisfactory spatial resolution beyond the ballistic (a few hundred microns) and quasiballistic (1-2 mm) regimes. Photoacoustic tomography is based on the high optical contrast yet utilizing the high ultrasonic resolution. Our work in this emerging area of research will be summarized in this invited talk. In this technology, a diffraction-based inverse-source problem is solved in the image reconstruction, for which we developed the rigorous reconstruction theory. We implemented a prototype and accomplished noninvasive transdermal and transcranial functional imaging of small-animal brains in vivo. Change in the cerebral blood oxygenation of a rat, as a result of the alternation from hyperoxia to hypoxia, was imaged successfully. PMID:17271539

  4. Imaging Cells in Flow Cytometer Using Spatial-Temporal Transformation.

    PubMed

    Han, Yuanyuan; Lo, Yu-Hwa

    2015-01-01

    Flow cytometers measure fluorescence and light scattering and analyze multiple physical characteristics of a large population of single cells as cells flow in a fluid stream through an excitation light beam. Although flow cytometers have massive statistical power due to their single cell resolution and high throughput, they produce no information about cell morphology or spatial resolution offered by microscopy, which is a much wanted feature missing in almost all flow cytometers. In this paper, we invent a method of spatial-temporal transformation to provide flow cytometers with cell imaging capabilities. The method uses mathematical algorithms and a spatial filter as the only hardware needed to give flow cytometers imaging capabilities. Instead of CCDs or any megapixel cameras found in any imaging systems, we obtain high quality image of fast moving cells in a flow cytometer using PMT detectors, thus obtaining high throughput in manners fully compatible with existing cytometers. To prove the concept, we demonstrate cell imaging for cells travelling at a velocity of 0.2 m/s in a microfluidic channel, corresponding to a throughput of approximately 1,000 cells per second. PMID:26281956

  5. Slice imaging of photodissociation of spatially oriented molecules

    SciTech Connect

    Lipciuc, M. Laura; Brom, Alrik J. van den; Dinu, Laura; Janssen, Maurice H.M.

    2005-12-15

    An electrostatic ion lens to spatially orient parent molecules and to image the angular distribution of photofragments is presented. Photodissociation of laboratory-oriented molecules makes it possible to study the dynamics of the dissociation process in more detail compared to photodissociation of nonoriented molecules. Using the velocity map imaging technique in combination with the slice imaging technique, the spatial recoil distribution of the photofragments can be measured with high resolution and without symmetry restrictions. Insertion of orientation electrodes between the repeller and the extractor of a velocity mapping electrostatic lens severely distorts the ion trajectories. The position where the ions are focused by the lens, the focal length, can be very different in the directions parallel and perpendicular to the inserted orientation electrodes. The focal length depends on the exact dimensions and positions of the electrodes of the ion lens. As this dependence is different in both directions, this dependence can be used to correct for the distorted ion trajectories. We discuss the design of an electrostatic ion lens, which is able to orient parent molecules and map the velocity of the photofragments. We report sliced images of photofragments from photolysis of spatially oriented CD{sub 3}I molecules to demonstrate the experimental combination of molecular orientation and velocity map slice imaging with good resolution.

  6. Imaging Cells in Flow Cytometer Using Spatial-Temporal Transformation

    PubMed Central

    Han, Yuanyuan; Lo, Yu-Hwa

    2015-01-01

    Flow cytometers measure fluorescence and light scattering and analyze multiple physical characteristics of a large population of single cells as cells flow in a fluid stream through an excitation light beam. Although flow cytometers have massive statistical power due to their single cell resolution and high throughput, they produce no information about cell morphology or spatial resolution offered by microscopy, which is a much wanted feature missing in almost all flow cytometers. In this paper, we invent a method of spatial-temporal transformation to provide flow cytometers with cell imaging capabilities. The method uses mathematical algorithms and a spatial filter as the only hardware needed to give flow cytometers imaging capabilities. Instead of CCDs or any megapixel cameras found in any imaging systems, we obtain high quality image of fast moving cells in a flow cytometer using PMT detectors, thus obtaining high throughput in manners fully compatible with existing cytometers. To prove the concept, we demonstrate cell imaging for cells travelling at a velocity of 0.2 m/s in a microfluidic channel, corresponding to a throughput of approximately 1,000 cells per second. PMID:26281956

  7. Spatial resolution limits for synchrotron-based infrared spectromicroscopy

    SciTech Connect

    Levenson, Erika; Lerch, Philippe; Martin, Michael C.

    2007-10-15

    Detailed spatial resolution tests were performed on beamline 1.4.4 at the Advanced Light Source synchrotron facility in Berkeley, CA. The high-brightness synchrotron source is coupled at this beamline to a Thermo-Electron Continumum XL infrared microscope. Two types of resolution tests in both the mid-IR (using a KBr beamsplitter and an MCT-A* detector) and in the near-IR (using a CaF2 beamsplitter and an InGaAS detector) were performed and compared to a simple diffraction-limited spot size model. At the shorter wavelengths in the near-IR the experimental results begin to deviate from only diffraction-limited. The entire data set is fit using a combined diffraction-limit and demagnified electron beam source size model. This description experimentally verifies how the physical electron beam size of the synchrotron source demagnified to the sample stage on the endstation begins to dominate the focussed spot size and therefore spatial resolution at higher energies. We discuss how different facilities, beamlines, and microscopes will affect the achievable spatial resolution.

  8. Progress Toward A Very High Angular Resolution Imaging Spectrometer (VERIS)

    NASA Astrophysics Data System (ADS)

    Korendyke, Clarence M.; Vourlidas, A.; Landi, E.; Seely, J.; Klimchuck, J.

    2007-07-01

    Recent imaging at arcsecond (TRACE) and sub-arcsecond (VAULT) spatial resolution clearly show that structures with fine spatial scales play a key role in the physics of the upper solar atmosphere. Both theoretical and observational considerations point to the importance of small spatial scales, impulsive energy release, strong dynamics, and extreme plasma nonuniformity. Fundamental questions regarding the nature, structure, properties and dynamics of loops and filamentary structures in the upper atmosphere have been raised. To address these questions, we are developing a next generation, VEry high angular Resolution Imaging Spectrometer (VERIS) as a sounding rocket instrument. VERIS will obtain the necessary high spatial resolution, high fidelity measurements of plasma temperatures, densities and velocities. With broad simultaneous temperature coverage, the VERIS observations will directly address unresolved issues relating to interconnections of various temperature solar plasmas. VERIS will provide the first ever subarcsecond spectra of transition region and coronal structures. It will do so with a sufficient spectral resolution of to allow centroided Doppler velocity determinations to better than 3 km/s. VERIS uses a novel two element, normal incidence optical design with highly reflective EUV coatings to access a spectral range with broad temperature coverage (0.03-15 MK) and density-sensitive line ratios. Finally, in addition to the spectra, VERIS will simultaneously obtain spectrally pure slot images (10x150 arcsec) in the +/-1 grating orders, which can be combined to make instantaneous line-of-sight velocity maps with 8km/s accuracy over an unprecedented field of view. The VERIS program is beginning the second year of its three year development cycle. All design activities and reviews are complete. Fabrication of all major components has begun. Brassboard electronics cards have been fabricated, assembled and tested. The paper presents the essential scientific

  9. X-ray characterization of CMOS imaging detector with high resolution for fluoroscopic imaging application

    NASA Astrophysics Data System (ADS)

    Cha, Bo Kyung; Kim, Cho Rong; Jeon, Seongchae; Kim, Ryun Kyung; Seo, Chang-Woo; Yang, Keedong; Heo, Duchang; Lee, Tae-Bum; Shin, Min-Seok; Kim, Jong-Boo; Kwon, Oh-Kyung

    2013-12-01

    This paper introduces complementary metal-oxide semiconductor (CMOS) active pixel sensor (APS)-based X-ray imaging detectors with high spatial resolution for medical imaging application. In this study, our proposed X-ray CMOS imaging sensor has been fabricated by using a 0.35 μm 1 Poly 4 Metal CMOS process. The pixel size is 100 μm×100 μm and the pixel array format is 24×96 pixels, which provide a field-of-view (FOV) of 9.6 mm×2.4 mm. The 14.3-bit extend counting analog-to digital converter (ADC) with built-in binning mode was used to reduce the area and simultaneously improve the image resolution. Both thallium-doped CsI (CsI:Tl) and Gd2O2S:Tb scintillator screens were used as converters for incident X-rays to visible light photons. The optical property and X-ray imaging characterization such as X-ray to light response as a function of incident X-ray exposure dose, spatial resolution and X-ray images of objects were measured under different X-ray energy conditions. The measured results suggest that our developed CMOS-based X-ray imaging detector has the potential for fluoroscopic imaging and cone-beam computed tomography (CBCT) imaging applications.

  10. Superresolved multiphoton microscopy with spatial frequency-modulated imaging.

    PubMed

    Field, Jeffrey J; Wernsing, Keith A; Domingue, Scott R; Allende Motz, Alyssa M; DeLuca, Keith F; Levi, Dean H; DeLuca, Jennifer G; Young, Michael D; Squier, Jeff A; Bartels, Randy A

    2016-06-14

    Superresolved far-field microscopy has emerged as a powerful tool for investigating the structure of objects with resolution well below the diffraction limit of light. Nearly all superresolution imaging techniques reported to date rely on real energy states of fluorescent molecules to circumvent the diffraction limit, preventing superresolved imaging with contrast mechanisms that occur via virtual energy states, including harmonic generation (HG). We report a superresolution technique based on spatial frequency-modulated imaging (SPIFI) that permits superresolved nonlinear microscopy with any contrast mechanism and with single-pixel detection. We show multimodal superresolved images with two-photon excited fluorescence (TPEF) and second-harmonic generation (SHG) from biological and inorganic media. Multiphoton SPIFI (MP-SPIFI) provides spatial resolution up to 2η below the diffraction limit, where η is the highest power of the nonlinear intensity response. MP-SPIFI can be used to provide enhanced resolution in optically thin media and may provide a solution for superresolved imaging deep in scattering media. PMID:27231219

  11. Signal Amplification Technique (SAT): an approach for improving resolution and reducing image noise in computed tomography

    SciTech Connect

    Phelps, M.E.; Huang, S.C.; Hoffman, E.J.; Plummer, D.; Carson, R.

    1981-01-01

    Spatial resolution improvements in computed tomography (CT) have been limited by the large and unique error propagation properties of this technique. The desire to provide maximum image resolution has resulted in the use of reconstruction filter functions designed to produce tomographic images with resolution as close as possible to the intrinsic detector resolution. Thus, many CT systems produce images with excessive noise with the system resolution determined by the detector resolution rather than the reconstruction algorithm. CT is a rigorous mathematical technique which applies an increasing amplification to increasing spatial frequencies in the measured data. This mathematical approach to spatial frequency amplification cannot distinguish between signal and noise and therefore both are amplified equally. We report here a method in which tomographic resolution is improved by using very small detectors to selectively amplify the signal and not noise. Thus, this approach is referred to as the signal amplification technique (SAT). SAT can provide dramatic improvements in image resolution without increases in statistical noise or dose because increases in the cutoff frequency of the reconstruction algorithm are not required to improve image resolution. Alternatively, in cases where image counts are low, such as in rapid dynamic or receptor studies, statistical noise can be reduced by lowering the cutoff frequency while still maintaining the best possible image resolution. A possible system design for a positron CT system with SAT is described.

  12. Investigation of spatial resolution and temporal performance of SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout) with integrated electrostatic focusing

    NASA Astrophysics Data System (ADS)

    Scaduto, David A.; Lubinsky, Anthony R.; Rowlands, John A.; Kenmotsu, Hidenori; Nishimoto, Norihito; Nishino, Takeshi; Tanioka, Kenkichi; Zhao, Wei

    2014-03-01

    We have previously proposed SAPHIRE (scintillator avalanche photoconductor with high resolution emitter readout), a novel detector concept with potentially superior spatial resolution and low-dose performance compared with existing flat-panel imagers. The detector comprises a scintillator that is optically coupled to an amorphous selenium photoconductor operated with avalanche gain, known as high-gain avalanche rushing photoconductor (HARP). High resolution electron beam readout is achieved using a field emitter array (FEA). This combination of avalanche gain, allowing for very low-dose imaging, and electron emitter readout, providing high spatial resolution, offers potentially superior image quality compared with existing flat-panel imagers, with specific applications to fluoroscopy and breast imaging. Through the present collaboration, a prototype HARP sensor with integrated electrostatic focusing and nano- Spindt FEA readout technology has been fabricated. The integrated electron-optic focusing approach is more suitable for fabricating large-area detectors. We investigate the dependence of spatial resolution on sensor structure and operating conditions, and compare the performance of electrostatic focusing with previous technologies. Our results show a clear dependence of spatial resolution on electrostatic focusing potential, with performance approaching that of the previous design with external mesh-electrode. Further, temporal performance (lag) of the detector is evaluated and the results show that the integrated electrostatic focusing design exhibits comparable or better performance compared with the mesh-electrode design. This study represents the first technical evaluation and characterization of the SAPHIRE concept with integrated electrostatic focusing.

  13. Electron-optic limitations on image resolution

    NASA Technical Reports Server (NTRS)

    Engstrom, R. W.

    1973-01-01

    Various approaches are considered to the solution of the electron-optical problem of designing an image tube configuration. Emphasis is placed on the method of computer design, and an illustration is given in which the technique is used in the design of an 80-mm image tube with a zoom capability of 3:1. The solutions are discussed to such problems as image distortion, magnification, and electron bundles striking the zoom electrode. Three types of an electron-optical configuration are examined for the electron-optic limitations to resolution: (1) the proximity image tube, (2) the magnetic-type image tube having uniform electric and magnetic fields, and (3) the electrostatic-type image tube such as the 80-mm zoom tube.

  14. Transillumination spatially modulated illumination microscopy for human chromosome imaging

    NASA Astrophysics Data System (ADS)

    Pitris, Costas; Heracleous, Peter; Patsalis, Philippos

    2005-03-01

    Human chromosome analysis is an essential task in cytogenetics, especially in prenatal screening, genetic syndrome diagnosis, cancer pathology research and mutagen dosimetry. Chromosomal analysis begins with the creation of a karyotype, which is a layout of chromosome images organized by decreasing size in pairs. Both manual and automatic classification of chromosomes are limited by the resolution of the microscope and imaging system used. One way to improve the results of classification and even detect subtleties now remaining undetected, is to enhance the resolution of the images. It is possible to achieve lateral resolution beyond the classical limit, by using spatially modulated illumination (SMI) in a wide-field, non-confocal microscope. In this case, the sample is illuminated with spatially modulated light, which makes normally inaccessible high-resolution information visible in the observed image by shifting higher frequencies within the OTF limits of the microscope. Although, SMI microscopes have been reported in the past, this manuscript reports the development of a transillumination microscope for opaque, non-fluorescent samples. The illumination path consisted of a light source illuminating a ruled grating which was subsequently imaged on the sample. The grating was mounted on a rotating and translating stage so that the magnification and rotation of the pattern could be adjusted. The imaging lens was a 1.25 NA oil immersion objective. Test samples showed resolution improvement, as judged from a comparison of the experimentally obtained FWHM. Further studies using smaller fringe distance or laser interference pattern illumination will be evaluated to further optimize the SMI results.

  15. Estimation of yield and water requirements of maize crops combining high spatial and temporal resolution images with a simple crop model, in the perspective of the Sentinel-2 mission

    NASA Astrophysics Data System (ADS)

    Battude, Marjorie; Bitar, Ahmad Al; Brut, Aurore; Cros, Jérôme; Dejoux, Jean-François; Huc, Mireille; Marais Sicre, Claire; Tallec, Tiphaine; Demarez, Valérie

    2016-04-01

    Water resources are under increasing pressure as a result of global change and of a raising competition among the different users (agriculture, industry, urban). It is therefore important to develop tools able to estimate accurately crop water requirements in order to optimize irrigation while maintaining acceptable production. In this context, remote sensing is a valuable tool to monitor vegetation development and water demand. This work aims at developing a robust and generic methodology mainly based on high resolution remote sensing data to provide accurate estimates of maize yield and water needs at the watershed scale. Evapotranspiration (ETR) and dry aboveground biomass (DAM) of maize crops were modeled using time series of GAI images used to drive a simple agro-meteorological crop model (SAFYE, Duchemin et al., 2005). This model is based on a leaf partitioning function (Maas, 1993) for the simulation of crop biomass and on the FAO-56 methodology for the ETR simulation. The model also contains a module to simulate irrigation. This study takes advantage of the SPOT4 and SPOT5 Take5 experiments initiated by CNES (http://www.cesbio.ups-tlse.fr/multitemp/). They provide optical images over the watershed from February to May 2013 and from April to August 2015 respectively, with a temporal and spatial resolution similar to future images from the Sentinel-2 and VENμS missions. This dataset was completed with LandSat8 and Deimos1 images in order to cover the whole growing season while reducing the gaps in remote sensing time series. Radiometric, geometric and atmospheric corrections were achieved by the THEIA land data center, and the KALIDEOS processing chain. The temporal dynamics of the green area index (GAI) plays a key role in soil-plant-atmosphere interactions and in biomass accumulation process. Consistent seasonal dynamics of the remotely sensed GAI was estimated by applying a radiative transfer model based on artificial neural networks (BVNET, Baret

  16. Subcell resolution in simplex stochastic collocation for spatial discontinuities

    NASA Astrophysics Data System (ADS)

    Witteveen, Jeroen A. S.; Iaccarino, Gianluca

    2013-10-01

    Subcell resolution has been used in the Finite Volume Method (FVM) to obtain accurate approximations of discontinuities in the physical space. Stochastic methods are usually based on local adaptivity for resolving discontinuities in the stochastic dimensions. However, the adaptive refinement in the probability space is ineffective in the non-intrusive uncertainty quantification framework, if the stochastic discontinuity is caused by a discontinuity in the physical space with a random location. The dependence of the discontinuity location in the probability space on the spatial coordinates then results in a staircase approximation of the statistics, which leads to first-order error convergence and an underprediction of the maximum standard deviation. To avoid these problems, we introduce subcell resolution into the Simplex Stochastic Collocation (SSC) method for obtaining a truly discontinuous representation of random spatial discontinuities in the interior of the cells discretizing the probability space. The presented SSC-SR method is based on resolving the discontinuity location in the probability space explicitly as function of the spatial coordinates and extending the stochastic response surface approximations up to the predicted discontinuity location. The applications to a linear advection problem, the inviscid Burgers' equation, a shock tube problem, and the transonic flow over the RAE 2822 airfoil show that SSC-SR resolves random spatial discontinuities with multiple stochastic and spatial dimensions accurately using a minimal number of samples.

  17. Subcell resolution in simplex stochastic collocation for spatial discontinuities

    SciTech Connect

    Witteveen, Jeroen A.S.; Iaccarino, Gianluca

    2013-10-15

    Subcell resolution has been used in the Finite Volume Method (FVM) to obtain accurate approximations of discontinuities in the physical space. Stochastic methods are usually based on local adaptivity for resolving discontinuities in the stochastic dimensions. However, the adaptive refinement in the probability space is ineffective in the non-intrusive uncertainty quantification framework, if the stochastic discontinuity is caused by a discontinuity in the physical space with a random location. The dependence of the discontinuity location in the probability space on the spatial coordinates then results in a staircase approximation of the statistics, which leads to first-order error convergence and an underprediction of the maximum standard deviation. To avoid these problems, we introduce subcell resolution into the Simplex Stochastic Collocation (SSC) method for obtaining a truly discontinuous representation of random spatial discontinuities in the interior of the cells discretizing the probability space. The presented SSC–SR method is based on resolving the discontinuity location in the probability space explicitly as function of the spatial coordinates and extending the stochastic response surface approximations up to the predicted discontinuity location. The applications to a linear advection problem, the inviscid Burgers’ equation, a shock tube problem, and the transonic flow over the RAE 2822 airfoil show that SSC–SR resolves random spatial discontinuities with multiple stochastic and spatial dimensions accurately using a minimal number of samples.

  18. Low-Rank Total Variation for Image Super-Resolution

    PubMed Central

    Shi, Feng; Cheng, Jian; Wang, Li; Yap, Pew-Thian; Shen, Dinggang

    2014-01-01

    Most natural images can be approximated using their low-rank components. This fact has been successfully exploited in recent advancements of matrix completion algorithms for image recovery. However, a major limitation of low-rank matrix completion algorithms is that they cannot recover the case where a whole row or column is missing. The missing row or column will be simply filled as an arbitrary combination of other rows or columns with known values. This precludes the application of matrix completion to problems such as super-resolution (SR) where missing values in many rows and columns need to be recovered in the process of up-sampling a low-resolution image. Moreover, low-rank regularization considers information globally from the whole image and does not take proper consideration of local spatial consistency. Accordingly, we propose in this paper a solution to the SR problem via simultaneous (global) low-rank and (local) total variation (TV) regularization. We solve the respective cost function using the alternating direction method of multipliers (ADMM). Experiments on MR images of adults and pediatric subjects demonstrate that the proposed method enhances the details of the recovered high-resolution images, and outperforms the nearest-neighbor interpolation, cubic interpolation, non-local means, and TV-based up-sampling. PMID:24505661

  19. High spatial resolution brain functional MRI using submillimeter balanced steady-state free precession acquisition

    SciTech Connect

    Wu, Pei-Hsin; Chung, Hsiao-Wen; Tsai, Ping-Huei; Wu, Ming-Long; Chuang, Tzu-Chao; Shih, Yi-Yu; Huang, Teng-Yi

    2013-12-15

    Purpose: One of the technical advantages of functional magnetic resonance imaging (fMRI) is its precise localization of changes from neuronal activities. While current practice of fMRI acquisition at voxel size around 3 × 3 × 3 mm{sup 3} achieves satisfactory results in studies of basic brain functions, higher spatial resolution is required in order to resolve finer cortical structures. This study investigated spatial resolution effects on brain fMRI experiments using balanced steady-state free precession (bSSFP) imaging with 0.37 mm{sup 3} voxel volume at 3.0 T. Methods: In fMRI experiments, full and unilateral visual field 5 Hz flashing checkerboard stimulations were given to healthy subjects. The bSSFP imaging experiments were performed at three different frequency offsets to widen the coverage, with functional activations in the primary visual cortex analyzed using the general linear model. Variations of the spatial resolution were achieved by removing outerk-space data components. Results: Results show that a reduction in voxel volume from 3.44 × 3.44 × 2 mm{sup 3} to 0.43 × 0.43 × 2 mm{sup 3} has resulted in an increase of the functional activation signals from (7.7 ± 1.7)% to (20.9 ± 2.0)% at 3.0 T, despite of the threefold SNR decreases in the original images, leading to nearly invariant functional contrast-to-noise ratios (fCNR) even at high spatial resolution. Activation signals aligning nicely with gray matter sulci at high spatial resolution would, on the other hand, have possibly been mistaken as noise at low spatial resolution. Conclusions: It is concluded that the bSSFP sequence is a plausible technique for fMRI investigations at submillimeter voxel widths without compromising fCNR. The reduction of partial volume averaging with nonactivated brain tissues to retain fCNR is uniquely suitable for high spatial resolution applications such as the resolving of columnar organization in the brain.

  20. Auditory spatial resolution in horizontal, vertical, and diagonal planes

    NASA Astrophysics Data System (ADS)

    Grantham, D. Wesley; Hornsby, Benjamin W. Y.; Erpenbeck, Eric A.

    2003-08-01

    Minimum audible angle (MAA) and minimum audible movement angle (MAMA) thresholds were measured for stimuli in horizontal, vertical, and diagonal (60°) planes. A pseudovirtual technique was employed in which signals were recorded through KEMAR's ears and played back to subjects through insert earphones. Thresholds were obtained for wideband, high-pass, and low-pass noises. Only 6 of 20 subjects obtained wideband vertical-plane MAAs less than 10°, and only these 6 subjects were retained for the complete study. For all three filter conditions thresholds were lowest in the horizontal plane, slightly (but significantly) higher in the diagonal plane, and highest for the vertical plane. These results were similar in magnitude and pattern to those reported by Perrott and Saberi [J. Acoust. Soc. Am. 87, 1728-1731 (1990)] and Saberi and Perrott [J. Acoust. Soc. Am. 88, 2639-2644 (1990)], except that these investigators generally found that thresholds for diagonal planes were as good as those for the horizontal plane. The present results are consistent with the hypothesis that diagonal-plane performance is based on independent contributions from a horizontal-plane system (sensitive to interaural differences) and a vertical-plane system (sensitive to pinna-based spectral changes). Measurements of the stimuli recorded through KEMAR indicated that sources presented from diagonal planes can produce larger interaural level differences (ILDs) in certain frequency regions than would be expected based on the horizontal projection of the trajectory. Such frequency-specific ILD cues may underlie the very good performance reported in previous studies for diagonal spatial resolution. Subjects in the present study could apparently not take advantage of these cues in the diagonal-plane condition, possibly because they did not externalize the images to their appropriate positions in space or possibly because of the absence of a patterned visual field.

  1. From high spatial resolution imagery to spatial indicators : Application for hydromorphy follow-up on Bourgneuf wetland

    NASA Astrophysics Data System (ADS)

    Bailly, J. S.; Puech, C.; Lukac, F.; Massé, J.

    2003-04-01

    On Atlantic coastal wetlands, the understanding of hydrological processes may refer to hydraulic surface structures characterization as small ditches or channels networks, permanent and temporary water bodies. Moreover to improve the understanding, this characerization should be realized regarding different seasons and different spatial scales: elementary parcel, managment unit and whole wetland scales. In complement to usual observations on a few local ground points, high spatial resolution remote sensing may be a good information support for extraction and characterization on elementary objects, especially water bodies, permanents or temporary ones and ditches. To carry out a floow-up on wetlands, a seasonal image acquisition rate, reachable from most of satelite systems, is in that case informative for hydrological needs. In this work, georeferencing methods on openfield wetlands have been handled with care in order to use diachronic images or combined geographical data; lack of relief, short vegetation and well structured landscape make this preprocess easier in comparison to other landscape situations. In this presentation we focus on spatial hydromorphy parameters constructed from images with specific processes. Especially, hydromorphy indicators for parcels or managment units have been developped using an IRC winter-spring-summer metric resolution set of images: these descriptors are based on water areas evolution or hydrophyl vegetations presence traducing hydrodynamic submersion behaviour in temporary water bodies. An other example presents a surface water network circulation indicator elaborated on IRC aerial photography combined with vectorized geographic database. This indicator is based on ditches width and vegetation presence : a specific process uses vectorized geo data set to define transects across ditches on which classified image analysis is carried out (supervised classification). These first results proposing hydromorphy descriptors from very

  2. High-Resolution Solar Imaging With Photon Sieves

    NASA Astrophysics Data System (ADS)

    Oktem, F. S.; Kamalabadi, F.; Davila, J. M.

    2014-12-01

    A photon sieve is a modification of a Fresnel zone plate in which open zones are replaced by a large number of circular holes. This lightweight optical device offers a superior image forming capability compared with the Fresnel zone plate, and is specially suited to observations at UV and x-ray wavelengths where refractive lenses are not available due to strong absorption of materials, and reflective mirrors are difficult to manufacture to achieve near diffraction-limited resolution. At these shorter wavelengths, photon sieves enable diffraction-limited imaging performance with relaxed manufacturing tolerances, and simple and low-cost fabrication. In this work, we present a new photon sieve imaging modality that, unlike previous designs, takes advantage of chromatic aberration. The fact that different wavelengths are focused at different distances from photon sieve is exploited to develop a novel multi-spectral imaging technique. The idea is to use a photon sieve imaging system with a moving detector which records images at different planes. Each measurement consists of superimposed images of different wavelengths, with each individual image being either in focus or out of focus. For spatially incoherent illumination, we study the problem of recovering the individual images from these superimposed measurements. We first formulate the discrete forward problem using the closed-form Fresnel imaging formulas. The inverse problem is then a multi-frame deconvolution problem involving multiple objects, and is formulated as a maximum posterior estimation problem. The resulting nonlinear optimization problem is solved using a fixed-point iterative algorithm. In contrast to traditional spectral imagers employing a series of wavelength filters, the proposed technique relies on a simple optical system, but incorporates powerful image processing methods to form spectral images computationally. In addition to diffraction-limited high spatial resolution enabled by photon sieves

  3. High-resolution adaptive imaging with a single photodiode

    NASA Astrophysics Data System (ADS)

    Soldevila, F.; Salvador-Balaguer, E.; Clemente, P.; Tajahuerce, E.; Lancis, J.

    2015-09-01

    During the past few years, the emergence of spatial light modulators operating at the tens of kHz has enabled new imaging modalities based on single-pixel photodetectors. The nature of single-pixel imaging enforces a reciprocal relationship between frame rate and image size. Compressive imaging methods allow images to be reconstructed from a number of projections that is only a fraction of the number of pixels. In microscopy, single-pixel imaging is capable of producing images with a moderate size of 128 × 128 pixels at frame rates under one Hz. Recently, there has been considerable interest in the development of advanced techniques for high-resolution real-time operation in applications such as biological microscopy. Here, we introduce an adaptive compressive technique based on wavelet trees within this framework. In our adaptive approach, the resolution of the projecting patterns remains deliberately small, which is crucial to avoid the demanding memory requirements of compressive sensing algorithms. At pattern projection rates of 22.7 kHz, our technique would enable to obtain 128 × 128 pixel images at frame rates around 3 Hz. In our experiments, we have demonstrated a cost-effective solution employing a commercial projection display.

  4. High-resolution adaptive imaging with a single photodiode

    PubMed Central

    Soldevila, F.; Salvador-Balaguer, E.; Clemente, P.; Tajahuerce, E.; Lancis, J.

    2015-01-01

    During the past few years, the emergence of spatial light modulators operating at the tens of kHz has enabled new imaging modalities based on single-pixel photodetectors. The nature of single-pixel imaging enforces a reciprocal relationship between frame rate and image size. Compressive imaging methods allow images to be reconstructed from a number of projections that is only a fraction of the number of pixels. In microscopy, single-pixel imaging is capable of producing images with a moderate size of 128 × 128 pixels at frame rates under one Hz. Recently, there has been considerable interest in the development of advanced techniques for high-resolution real-time operation in applications such as biological microscopy. Here, we introduce an adaptive compressive technique based on wavelet trees within this framework. In our adaptive approach, the resolution of the projecting patterns remains deliberately small, which is crucial to avoid the demanding memory requirements of compressive sensing algorithms. At pattern projection rates of 22.7 kHz, our technique would enable to obtain 128 × 128 pixel images at frame rates around 3 Hz. In our experiments, we have demonstrated a cost-effective solution employing a commercial projection display. PMID:26382114

  5. Test-Retest Reliability of High Angular Resolution Diffusion Imaging Acquisition within Medial Temporal Lobe Connections Assessed via Tract Based Spatial Statistics, Probabilistic Tractography and a Novel Graph Theory Metric

    PubMed Central

    Kuhn, T.; Gullett, J. M.; Nguyen, P.; Boutzoukas, A. E.; Ford, A.; Colon-Perez, L. M.; Triplett, W.; Carney, P.R.; Mareci, T. H.; Price, C. C.; Bauer, R. M.

    2015-01-01

    Introduction This study examined the reliability of high angular resolution diffusion tensor imaging (HARDI) data collected on a single individual across several sessions using the same scanner. Methods HARDI data was acquired for one healthy adult male at the same time of day on ten separate days across a one-month period. Environmental factors (e.g. temperature) were controlled across scanning sessions. Tract Based Spatial Statistics (TBSS) was used to assess session-to-session variability in measures of diffusion, fractional anisotropy (FA) and mean diffusivity (MD). To address reliability within specific structures of the medial temporal lobe (MTL; the focus of an ongoing investigation), probabilistic tractography segmented the Entorhinal cortex (ERc) based on connections with Hippocampus (HC), Perirhinal (PRc) and Parahippocampal (PHc) cortices. Streamline tractography generated edge weight (EW) metrics for the aforementioned ERc connections and, as comparison regions, connections between left and right rostral and caudal anterior cingulate cortex (ACC). Coefficients of variation (CoV) were derived for the surface area and volumes of these ERc connectivity-defined regions (CDR) and for EW across all ten scans, expecting that scan-to-scan reliability would yield low CoVs. Results TBSS revealed no significant variation in FA or MD across scanning sessions. Probabilistic tractography successfully reproduced histologically-verified adjacent medial temporal lobe circuits. Tractography-derived metrics displayed larger ranges of scanner-to-scanner variability. Connections involving HC displayed greater variability than metrics of connection between other investigated regions. Conclusions By confirming the test retest reliability of HARDI data acquisition, support for the validity of significant results derived from diffusion data can be obtained. PMID:26189060

  6. Test-retest reliability of high angular resolution diffusion imaging acquisition within medial temporal lobe connections assessed via tract based spatial statistics, probabilistic tractography and a novel graph theory metric.

    PubMed

    Kuhn, T; Gullett, J M; Nguyen, P; Boutzoukas, A E; Ford, A; Colon-Perez, L M; Triplett, W; Carney, P R; Mareci, T H; Price, C C; Bauer, R M

    2016-06-01

    This study examined the reliability of high angular resolution diffusion tensor imaging (HARDI) data collected on a single individual across several sessions using the same scanner. HARDI data was acquired for one healthy adult male at the same time of day on ten separate days across a one-month period. Environmental factors (e.g. temperature) were controlled across scanning sessions. Tract Based Spatial Statistics (TBSS) was used to assess session-to-session variability in measures of diffusion, fractional anisotropy (FA) and mean diffusivity (MD). To address reliability within specific structures of the medial temporal lobe (MTL; the focus of an ongoing investigation), probabilistic tractography segmented the Entorhinal cortex (ERc) based on connections with Hippocampus (HC), Perirhinal (PRc) and Parahippocampal (PHc) cortices. Streamline tractography generated edge weight (EW) metrics for the aforementioned ERc connections and, as comparison regions, connections between left and right rostral and caudal anterior cingulate cortex (ACC). Coefficients of variation (CoV) were derived for the surface area and volumes of these ERc connectivity-defined regions (CDR) and for EW across all ten scans, expecting that scan-to-scan reliability would yield low CoVs. TBSS revealed no significant variation in FA or MD across scanning sessions. Probabilistic tractography successfully reproduced histologically-verified adjacent medial temporal lobe circuits. Tractography-derived metrics displayed larger ranges of scanner-to-scanner variability. Connections involving HC displayed greater variability than metrics of connection between other investigated regions. By confirming the test retest reliability of HARDI data acquisition, support for the validity of significant results derived from diffusion data can be obtained. PMID:26189060

  7. High-resolution spatial mapping of shear properties in cartilage.

    PubMed

    Buckley, Mark R; Bergou, Attila J; Fouchard, Jonathan; Bonassar, Lawrence J; Cohen, Itai

    2010-03-01

    Structural properties of articular cartilage such as proteoglycan content, collagen content and collagen alignment are known to vary over length scales as small as a few microns (Bullough and Goodfellow, 1968; Bi et al., 2006). Characterizing the resulting variation in mechanical properties is critical for understanding how the inhomogeneous architecture of this tissue gives rise to its function. Previous studies have measured the depth-dependent shear modulus of articular cartilage using methods such as particle image velocimetry (PIV) that rely on cells and cell nuclei as fiducial markers to track tissue deformation (Buckley et al., 2008; Wong et al., 2008a). However, such techniques are limited by the density of trackable markers, which may be too low to take full advantage of optical microscopy. This limitation leads to noise in the acquired data, which is often exacerbated when the data is manipulated. In this study, we report on two techniques for increasing the accuracy of tissue deformation measurements. In the first technique, deformations were tracked in a grid that was photobleached on each tissue sample (Bruehlmann et al., 2004). In the second, a numerical technique was implemented that allowed for accurate differentiation of optical displacement measurements by minimizing the propagated experimental error while ensuring that truncation error associated with local averaging of the data remained small. To test their efficacy, we employed these techniques to compare the depth-dependent shear moduli of neonatal bovine and adult human articular cartilage. Using a photobleached grid and numerical optimization to gather and analyze data led to results consistent with those reported previously (Buckley et al., 2008; Wong et al., 2008a), but with increased spatial resolution and characteristic coefficients of variation that were reduced up to a factor of 3. This increased resolution allowed us to determine that the shear modulus of neonatal bovine and adult

  8. Low-Cost Ultra-High Spatial and Temporal Resolution Mapping of Intertidal Rock Platforms

    NASA Astrophysics Data System (ADS)

    Bryson, M.; Johnson-Roberson, M.; Murphy, R.

    2012-07-01

    Intertidal ecosystems have primarily been studied using field-based sampling; remote sensing offers the ability to collect data over large areas in a snapshot of time which could compliment field-based sampling methods by extrapolating them into the wider spatial and temporal context. Conventional remote sensing tools (such as satellite and aircraft imaging) provide data at relatively course, sub-meter resolutions or with limited temporal resolutions and relatively high costs for small-scale environmental science and ecology studies. In this paper, we describe a low-cost, kite-based imaging system and photogrammetric pipeline that was developed for constructing highresolution, 3D, photo-realistic terrain models of intertidal rocky shores. The processing pipeline uses automatic image feature detection and matching, structure-from-motion and photo-textured terrain surface reconstruction algorithms that require minimal human input and only a small number of ground control points and allow the use of cheap, consumer-grade digital cameras. The resulting maps combine colour and topographic information at sub-centimeter resolutions over an area of approximately 100m, thus enabling spatial properties of the intertidal environment to be determined across a hierarchy of spatial scales. Results of the system are presented for an intertidal rock platform at Cape Banks, Sydney, Australia. Potential uses of this technique include mapping of plant (micro- and macro-algae) and animal (e.g. gastropods) assemblages at multiple spatial and temporal scales.

  9. Experimental calibration of x-ray camera performance: spatial resolution, flat field response, and radiation sensitivity

    NASA Astrophysics Data System (ADS)

    Xie, Hongwei; Chen, Jinchuan; Li, Linbo; Zhang, Faqiang; Chen, Dingyang

    2014-11-01

    Major parameters of X-rays camera include spatial resolution, flat field response and dynamic range. Such parameters were calibrated on a pulsed X-rays source with about 0.3MeV energy. Fluorophotometric method was used for the measurement of spatial resolutions of the penetrating lights and reflecting lights. Results indicated they were both basically same. And the spatial resolution of the camera was measured with edge method. Corresponding to 10% intensity, the modulator transfer function (MTS) of the resolution was about 5lp/mm, while the size of the point spread function (PSF) was about 0.8mm. Due to the system design with both short distance and big filed of view, the flat field non-homogeneity was about 15%. In addition, because of the relatively big gain of the scintillator and MCP image intensifier and the limited detecting efficiency of the X-rays and scintillator, the image intensity of the flat field response demonstrated a big standard deviation of about 1375. Due to the crosstalk throughout the system, the maximal signal-to-noise ratio (SNR) of the X-rays camera was about 10:1.These results could provide important technical specifications for both applications of X-rays camera and data processing of other relevant images.

  10. Towards Adaptive High-Resolution Images Retrieval Schemes

    NASA Astrophysics Data System (ADS)

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

    2016-06-01

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

  11. Higher resolution satellite remote sensing and the impact on image mapping

    USGS Publications Warehouse

    Watkins, Allen H.; Thormodsgard, June M.

    1987-01-01

    Recent advances in spatial, spectral, and temporal resolution of civil land remote sensing satellite data are presenting new opportunities for image mapping applications. The U.S. Geological Survey's experimental satellite image mapping program is evolving toward larger scale image map products with increased information content as a result of improved image processing techniques and increased resolution. Thematic mapper data are being used to produce experimental image maps at 1:100,000 scale that meet established U.S. and European map accuracy standards. Availability of high quality, cloud-free, 30-meter ground resolution multispectral data from the Landsat thematic mapper sensor, along with 10-meter ground resolution panchromatic and 20-meter ground resolution multispectral data from the recently launched French SPOT satellite, present new cartographic and image processing challenges. The need to fully exploit these higher resolution data increases the complexity of processing the images into large-scale image maps. The removal of radiometric artifacts and noise prior to geometric correction can be accomplished by using a variety of image processing filters and transforms. Sensor modeling and image restoration techniques allow maximum retention of spatial and radiometric information. An optimum combination of spectral information and spatial resolution can be obtained by merging different sensor types. These processing techniques are discussed and examples are presented. 

  12. Spatial and spectral resolution necessary for remotely sensed vegetation studies

    NASA Technical Reports Server (NTRS)

    Rock, B. N.

    1982-01-01

    An outline is presented of the required spatial and spectral resolution needed for accurate vegetation discrimination and mapping studies as well as for determination of state of health (i.e., detection of stress symptoms) of actively growing vegetation. Good success was achieved in vegetation discrimination and mapping of a heterogeneous forest cover in the ridge and valley portion of the Appalachians using multispectral data acquired with a spatial resolution of 15 m (IFOV). A sensor system delivering 10 to 15 m spatial resolution is needed for both vegetation mapping and detection of stress symptoms. Based on the vegetation discrimination and mapping exercises conducted at the Lost River site, accurate products (vegetation maps) are produced using broad-band spectral data ranging from the .500 to 2.500 micron portion of the spectrum. In order of decreasing utility for vegetation discrimination, the four most valuable TM simulator VNIR bands are: 6 (1.55 to 1.75 microns), 3 (0.63 to 0.69 microns), 5 (1.00 to 1.30 microns) and 4 (0.76 to 0.90 microns).

  13. Wide band focusing x-ray spectrograph with spatial resolution

    SciTech Connect

    Pikuz, S. A.; Douglass, J. D.; Shelkovenko, T. A.; Sinars, D. B.; Hammer, D. A.

    2008-01-15

    A new, wide spectral bandwidth x-ray spectrograph, the wide-bandwidth focusing spectrograph with spatial resolution (WB-FSSR), based on spherically bent mica crystals, is described. The wide bandwidth is achieved by combining three crystals to form a large aperture dispersive element. Since the WB-FSSR covers a wide spectral band, it is very convenient for application as a routine diagnostic tool in experiments in which the desired spectral coverage is different from one test to the next. The WB-FSSR has been tested in imploding wire-array experiments on a 1 MA pulsed power machine, and x-ray spectra were recorded in the 1-20 A spectral band using different orders of mica crystal reflection. Using a two mirror-symmetrically placed WB-FSSR configuration, it was also possible to distinguish between a real spectral shift and a shift of recorded spectral lines caused by the spatial distribution of the radiating plasma. A spectral resolution of about 2000 was demonstrated and a spatial resolution of {approx}100 {mu}m was achieved in the spectral band of 5-10 A in second order of mica reflection. A simple method of numerical analysis of spectrograph capability is proposed.

  14. Energy-filtering TEM at high magnification: spatial resolution and detection limits.

    PubMed

    Grogger, Werner; Schaffer, Bernhard; Krishnan, Kannan M; Hofer, Ferdinand

    2003-09-01

    Energy-filtering TEM (EFTEM) has turned out to be a very efficient and rapid tool for the chemical characterization of a specimen on a nanometer and even subnanometer length scale. Especially, the detection and measurement of very thin layers has become a great application of this technique in many materials science fields, e.g. semiconductors and hard disk technology. There, the reliability of compositional profiles is an important issue. However, the experimentally obtainable spatial resolution strongly influences the appearance of a thin layer in an EFTEM image, when dimensions reach subnanometer levels, which mainly leads to a broadening of the layer in the image. This fact has to be taken into account, when measuring the thickness of such a thin layer. Additionally, the convolution decreases contrast which makes the layer less visible in the image and finally determines the detection limit. In this work we present a systematic study on specifically designed Mn/PdMn multilayer test specimens to explore the practical aspects of spatial resolution and detection limits in EFTEM. Although specific to the ionization edges used, we will present general conclusions about the practical limitations in terms of EFTEM spatial resolution. Additionally, work will be shown about low energy-loss imaging of thin oxide layers, where delocalization is the main factor responsible for broadening. PMID:12871810

  15. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    PubMed Central

    Li, Ke; Garrett, John; Ge, Yongshuai; Chen, Guang-Hong

    2014-01-01

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDIvol =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo®, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than FBP (and vice

  16. Statistical model based iterative reconstruction (MBIR) in clinical CT systems. Part II. Experimental assessment of spatial resolution performance

    SciTech Connect

    Li, Ke; Chen, Guang-Hong; Garrett, John; Ge, Yongshuai

    2014-07-15

    Purpose: Statistical model based iterative reconstruction (MBIR) methods have been introduced to clinical CT systems and are being used in some clinical diagnostic applications. The purpose of this paper is to experimentally assess the unique spatial resolution characteristics of this nonlinear reconstruction method and identify its potential impact on the detectabilities and the associated radiation dose levels for specific imaging tasks. Methods: The thoracic section of a pediatric phantom was repeatedly scanned 50 or 100 times using a 64-slice clinical CT scanner at four different dose levels [CTDI{sub vol} =4, 8, 12, 16 (mGy)]. Both filtered backprojection (FBP) and MBIR (Veo{sup ®}, GE Healthcare, Waukesha, WI) were used for image reconstruction and results were compared with one another. Eight test objects in the phantom with contrast levels ranging from 13 to 1710 HU were used to assess spatial resolution. The axial spatial resolution was quantified with the point spread function (PSF), while the z resolution was quantified with the slice sensitivity profile. Both were measured locally on the test objects and in the image domain. The dependence of spatial resolution on contrast and dose levels was studied. The study also features a systematic investigation of the potential trade-off between spatial resolution and locally defined noise and their joint impact on the overall image quality, which was quantified by the image domain-based channelized Hotelling observer (CHO) detectability index d′. Results: (1) The axial spatial resolution of MBIR depends on both radiation dose level and image contrast level, whereas it is supposedly independent of these two factors in FBP. The axial spatial resolution of MBIR always improved with an increasing radiation dose level and/or contrast level. (2) The axial spatial resolution of MBIR became equivalent to that of FBP at some transitional contrast level, above which MBIR demonstrated superior spatial resolution than

  17. High resolution Cerenkov light imaging of induced positron distribution in proton therapy

    SciTech Connect

    Yamamoto, Seiichi Fujii, Kento; Morishita, Yuki; Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

    2014-11-01

    Purpose: In proton therapy, imaging of the positron distribution produced by fragmentation during or soon after proton irradiation is a useful method to monitor the proton range. Although positron emission tomography (PET) is typically used for this imaging, its spatial resolution is limited. Cerenkov light imaging is a new molecular imaging technology that detects the visible photons that are produced from high-speed electrons using a high sensitivity optical camera. Because its inherent spatial resolution is much higher than PET, the authors can measure more precise information of the proton-induced positron distribution with Cerenkov light imaging technology. For this purpose, they conducted Cerenkov light imaging of induced positron distribution in proton therapy. Methods: First, the authors evaluated the spatial resolution of our Cerenkov light imaging system with a {sup 22}Na point source for the actual imaging setup. Then the transparent acrylic phantoms (100 × 100 × 100 mm{sup 3}) were irradiated with two different proton energies using a spot scanning proton therapy system. Cerenkov light imaging of each phantom was conducted using a high sensitivity electron multiplied charge coupled device (EM-CCD) camera. Results: The Cerenkov light’s spatial resolution for the setup was 0.76 ± 0.6 mm FWHM. They obtained high resolution Cerenkov light images of the positron distributions in the phantoms for two different proton energies and made fused images of the reference images and the Cerenkov light images. The depths of the positron distribution in the phantoms from the Cerenkov light images were almost identical to the simulation results. The decay curves derived from the region-of-interests (ROIs) set on the Cerenkov light images revealed that Cerenkov light images can be used for estimating the half-life of the radionuclide components of positrons. Conclusions: High resolution Cerenkov light imaging of proton-induced positron distribution was possible. The

  18. Effects of spatial configurations on the resolution of spatial working memory.

    PubMed

    Mutluturk, Aysu; Boduroglu, Aysecan

    2014-11-01

    Recent research demonstrated that people represent spatial information configurally and preservation of configural cues at retrieval helps memory for spatial locations (Boduroğlu & Shah, Memory & Cognition, 37(8), 1120-1131 2009; Jiang, Olson, & Chun, Journal of Experimental Psychology: Learning, Memory, and Cognition, 26(3), 683-702 2000). The present study investigated the effects of spatial configurations on the resolution of individual location representations. In an open-ended task, participants first studied a set of object locations (three and five locations). Then, in a test display where available configural cues were manipulated, participants were asked to determine the original location of a target object whose color was auditorially cued. The difference between the reported location and the original location was taken as a measure of spatial resolution. In three experiments, we consistently observed that the resolution of spatial representations was facilitated by the preservation of spatial configurations at retrieval. We argue that participants may be using available configural cues in conjunction with the summary representation (e.g., centroid) of the original display in the computation of target locations. PMID:24939236

  19. Requirements for a Moderate-Resolution Infrared Imaging Sounder (MIRIS)

    NASA Technical Reports Server (NTRS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Gerber, Andrew J.; Kuai, Le; Gontijo, I.; DeLeon, Berta; Susskind, Joel; Iredell, Lena; Bajpai, Shyam

    2013-01-01

    The high cost of imaging and sounding from space warrants exploration of new methods for obtaining the required information, including changing the spectral band sets, employing new technologies and merging instruments. In some cases we must consider relaxation of the current capability. In others, we expect higher performance. In general our goal is to meet the VIIRS and CrIS requirements while providing the enhanced next generation capabilities: 1) Hyperspectral Imaging in the Vis/NIR bands, 2) High Spatial Resolution Sounding in the Infrared bands. The former will improve the accuracy of ocean color products, aerosols and water vapor, surface vegetation and geology. The latter will enable the high-impact achieved by the current suite of hyperspectral infrared sounders to be achieved by the next generation high resolution forecast models. We examine the spectral, spatial and radiometric requirements for a next generation system and technologies that can be applied from the available inventory within government and industry. A two-band grating spectrometer instrument called the Moderate-resolution Infrared Imaging Sounder (MIRIS) is conceived that, when used with the planned NASA PACE Ocean Color Instrument (OCI) will meet the vast majority of CrIS and VIIRS requirements in the all bands and provide the next generation capabilities desired. MIRIS resource requirements are modest and the Technology Readiness Level is high leading to the expectation that the cost and risk of MIRIS will be reasonable.

  20. Requirements for a Moderate-resolution Infrared Imaging Sounder (MIRIS)

    NASA Astrophysics Data System (ADS)

    Pagano, Thomas S.; Aumann, Hartmut H.; Gerber, Andrew J.; Kuai, Le; Gontijo, I.; DeLeon, Berta; Susskind, Joel; Iredell, Lena; Bajpai, Shyam

    2013-09-01

    The high cost of imaging and sounding from space warrants exploration of new methods for obtaining the required information, including changing the spectral band sets, employing new technologies and merging instruments. In some cases we must consider relaxation of the current capability. In others, we expect higher performance. In general our goal is to meet the VIIRS and CrIS requirements while providing the enhanced next generation capabilities: 1) Hyperspectral Imaging in the Vis/NIR bands, 2) High Spatial Resolution Sounding in the Infrared bands. The former will improve the accuracy of ocean color products, aerosols and water vapor, surface vegetation and geology. The latter will enable the high-impact achieved by the current suite of hyperspectral infrared sounders to be achieved by the next generation high resolution forecast models. We examine the spectral, spatial and radiometric requirements for a next generation system and technologies that can be applied from the available inventory within government and industry. A two-band grating spectrometer instrument called the Moderate-resolution Infrared Imaging Sounder (MIRIS) is conceived that, when used with the planned NASA PACE Ocean Color Instrument (OCI) will meet the vast majority of CrIS and VIIRS requirements in the all bands and provide the next generation capabilities desired. MIRIS resource requirements are modest and the Technology Readiness Level is high leading to the expectation that the cost and risk of MIRIS will be reasonable.

  1. Impact of spatial resolution on thermal blooming phase compensation instability

    NASA Astrophysics Data System (ADS)

    Spencer, Mark F.; Cusumano, Salvatore J.; Schmidt, Jason D.; Fiorino, Steven T.

    2010-08-01

    Phase compensation instability (PCI) is the time-dependent development of spatial perturbations that occur within thermally bloomed high-energy laser (HEL) beams. These types of spatial perturbations act as local hot spots that create small negative lenses within the HEL beam. Closed-loop adaptive optics (AO) corrects for these spatial perturbations by applying small positive-lens phase compensations, which only increases the strength of the local hot spots and leads to runaway in the adaptive-optics servo. This study uses a straightforward wave-optics code to model horizontal propagation with the effects of thermal blooming for a focused Gaussian beam. The strength of the thermal blooming effects is characterized using the classic dimensionless distortion number. A nominal AO system is used to mitigate phase distortions accumulated from thermal blooming. Parameters within the AO system, such as the number of actuators on the deformable mirror and the resolution of the wavefront sensor, are varied to determine the impact of spatial resolution in the development of the PCI. A discussion is given on the potential use of control theory to diminish the effects of the PCI.

  2. High-resolution TFT-LCD for spatial light modulator

    NASA Astrophysics Data System (ADS)

    Lee, JaeWon; Kim, Yong-Hae; Byun, Chun-Won; Pi, Jae-Eun; Oh, Himchan; Kim, GiHeon; Lee, Myung-Lae; Chu, Hye-Yong; Hwang, Chi-Sun

    2014-06-01

    SLM with very fine pixel pitch is needed for the holographic display system. Among various kinds of SLMs, commercially available high resolution LCoS has been widely used as a spatial light modulator. But the size of commercially available LCoS SLM is limited because the manufacturing technology of LCoS is based on the semiconductor process developed on small size Si wafer. Recently very high resolution flat panel display panel (~500ppi) was developed as a "retina display". Until now, the pixel pitch of flat panel display is several times larger than the pixel pitch of LCoS. But considering the possibility of shrink down the pixel pitch with advanced lithographic tools, the application of flat panel display will make it possible to build a SLM with high spatial bandwidth product. We simulated High resolution TFT-LCD panel on glass substrate using oxide semiconductor TFT with pixel pitch of 20um. And we considered phase modulation behavior of LC(ECB) mode. The TFT-LCD panel is reflective type with 4-metal structure with organic planarization layers. The technical challenge for high resolution large area SLM will be discussed with very fine pixel.

  3. Low-resolution facial image restoration based on sparse representation

    NASA Astrophysics Data System (ADS)

    Li, Yuelong; Bian, Junjie; Feng, Jufu

    2011-11-01

    In this paper, a strategy of