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1

Exploration Activity: Global Cloud Patterns  

NSDL National Science Digital Library

In this activity, students characterize some global patterns of deep, cold-topped clouds visible on global infrared satellite images. They will apply these characterizations to answer questions about local and global patterns of precipitation. The questions concern what clouds are and how they form, atmospheric cooling, rising air, precipitation, and the use of remote satellite imagery to see precipitation-producing clouds and storms. They will also create animated global infrared satellite images and answer some questions concerning them.

Dempsey, Dave

2005-03-10

2

4-D display of satellite cloud images  

NASA Technical Reports Server (NTRS)

A technique has been developed to display GOES satellite cloud images in perspective over a topographical map. Cloud heights are estimated using temperatures from an infrared (IR) satellite image, surface temperature observations, and a climatological model of vertical temperature profiles. Cloud levels are discriminated from each other and from the ground using a pattern recognition algorithm based on the brightness variance technique of Coakley and Bretherton. The cloud regions found by the pattern recognizer are rendered in three-dimensional perspective over a topographical map by an efficient remap of the visible image. The visible shades are mixed with an artificial shade based on the geometry of the cloud-top surface, in order to enhance the texture of the cloud top.

Hibbard, William L.

1987-01-01

3

Waves, advection, and cloud patterns on Venus  

NASA Technical Reports Server (NTRS)

The stable layers adjacent to the nearly neutral layer within the Venus clouds are found to be capable of supporting vertically trapped, horizontally propagating waves with horizontal wavelengths of about 10 km and speeds of a few meters per second relative to the mean wind in the neutral layer. These waves may possibly be excited by turbulence within the neutral layer. Here, the properties of the waves, and the patterns which they might produce within the visible clouds if excited near the subsolar point are examined. The patterns can be in agreement with many features in images. The waves are capable of transferring momentum latitudinally to help maintain the general atmospheric spin, but at present we are not able to evaluate wave amplitudes. We also examine an alternative possibility that the cloud patterns are produced by advection and shearing by the mean zonal and meridional flow of blobs formed near the equator. It is concluded that advection and shearing by the mean flow is the most likely explanation for the general pattern of small scale striations.

Schinder, Paul J.; Gierasch, Peter J.; Leroy, Stephen S.; Smith, Michael D.

1990-01-01

4

Determine precipitation rates from visible and infrared satellite images of clouds by pattern recognition technique. Progress Report, 1 Jul. 1985 - 31 Mar. 1987 Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

A more advanced cloud pattern analysis algorithm was subsequently developed to take the shape and brightness of the various clouds into account in a manner that is more consistent with the human analyst's perception of GOES cloud imagery. The results of that classification scheme were compared with precipitation probabilities observed from ships of opportunity off the U.S. east coast to derive empirical regressions between cloud types and precipitation probability. The cloud morphology was then quantitatively and objectively used to map precipitation probabilities during two winter months during which severe cold air outbreaks were observed over the northwest Atlantic. Precipitation probabilities associated with various cloud types are summarized. Maps of precipitation probability derived from the cloud morphology analysis program for two months and the precipitation probability derived from thirty years of ship observation were observed.

Weinman, James A.; Garan, Louis

1987-01-01

5

The Research of Satellite Cloud Image Recognition Base on Variational Method and Texture Feature Analysis  

Microsoft Academic Search

Recently, the development of satellite cloud image processing technology has become very quick; the research aspects concentrate on judge the cloud type and classify the cloud mainly. These image processing methods relate to the subject category like image processing and pattern recognition etc; it has become one of the fields of most quickly development in the research of satellite image

Wei Shangguan; Yanling Hao; Zhizhong Lu; Peng Wu

2007-01-01

6

Merging images through pattern decomposition  

Microsoft Academic Search

Describes an approach to image merging based on pattern decomposition. Each source image is first transformed into a set of primitive pattern elements. Pattern sets for the various source images are then combined to form a single set for the composite image. Finally the composite is reconstructed from its set of primitives. The authors illustrate the pattern decomposition technique with

P. J. Burt; E. H. Adelson

1985-01-01

7

Cloud Patterns in Toronto, Ontario, Canada  

NSDL National Science Digital Library

This lesson is designed to help students gain knowledge in graphing a microset of data, then using the graphs to investigate trends in cloud coverage over a given locale. Students are provided content-related activities to enhance background knowledge in cloud types, and then are provided detailed instructions on how to download data from the MY NASA DATA Live Access Server (LAS) and to use Excel to graph the data. The graphs are then used to explore trends in cloud coverage over Toronto, Ontario, Canada for a given time period. The lesson provides detailed procedure, related links and sample graphs, follow-up questions and extensions, and Teacher Notes.

2010-03-14

8

Contented-Based Satellite Cloud Image Processing and Information Retrieval  

Microsoft Academic Search

Satellite cloud image is a kind of useful image which includes abundant information, for acquired this information, the image\\u000a processing and character extraction method adapt to satellite cloud image has to be used. Content-based satellite cloud image\\u000a processing and information retrieval (CBIPIR) is a very important problem in image processing and analysis field. The basic\\u000a character, like color, texture, edge

Yanling Hao; Wei Shangguan; Yi Zhu; Yanhong Tang

2007-01-01

9

Recognition methods on cloud amount, movement of clouds, and rain clouds for rainfall prediction using whole sky images  

NASA Astrophysics Data System (ADS)

The final target of our research is to develop a system for forecasting local concentrated heavy rain, such as guerrilla rainstorms, by using whole sky images taken on the ground. To construct this system, this paper proposes the following recognition methods: cloud amount, movement of clouds, and rain clouds. The experimental results show that red/blue (R/B) values are efficient for measuring the cloud amount. However, using the gravity of images and the difference among time-sequenced images is insufficient to recognize the movement of clouds and does not correlate well with the R/B values and rain.

Fujinuma, Kazuma; Arai, Masayuki

2014-04-01

10

Image segmentation based on data field and cloud model  

Microsoft Academic Search

There are many uncertainties in image segmentation, which needs theories and methods with uncertainty to handle. This paper proposes a novel method of image segmentation based on data field and cloud model, which considers the spatial information of image through data field, and handles the uncertainty of image through cloud model. The proposed method inspired from cognitive physics considers each

Kun Qin; Leihai Ou; Tao Wu; Yi Du

2010-01-01

11

Image Mining: Detecting Deforestation Patterns  

E-print Network

54 Chapter IV Image Mining: Detecting Deforestation Patterns Through Satellites Marcelino Pereira to analyze satellite images and extract knowledge from this kind of data. The Amazonia deforestation problem of change on deforested areas of Amazonia. The purpose of the authors is to present relevant technologies

Camara, Gilberto

12

Soviet image pattern recognition research  

SciTech Connect

This report is an assessment of the published Soviet image pattern recognition (IPR) research and was written by a panel of six US academic experts in that research field. Image pattern recognition is a set of technological research topics involving automatic or interactive computer processing of pictorial information, utilizing optical, electronic, and computer technologies. This report focuses on IPR system configuration (optical, hybrid, digital), and current research. The topical chapter headings are Image Processing Hardware and Software Preprocessing, Statistical Pattern Recognition, Computer Vision, and Optical Techniques and Systems. Soviet research in all areas of IPR is strong in theory, but limited by poor availability of equipment for generating and handling digital images, and digital computer hardware and software. Nevertheless, some Soviet IPR achievements compare favorably with those of the West. There is strong Soviet research in statistical pattern recognition, where fundamental relationships related to the factors determining error rates in classification of images are being developed. There has been good Soviet work in enhancement and restoration of images (visible and radar) of the surface of Venus. There is a strong Soviet development program in optics and optical processing related to IPR. Nevertheless, the state of Soviet research in computer vision is ten to fifteen years behind the West, because of the lack of adequate hardware and software. The Soviet scientists in the area appear competent and knowledgeable of Western work, so that any improvement in their research output would be derived from access to more capable equipment. 402 refs., 4 figs., 4 tabs.

McKenney, B.L.; McGrain, M. (eds.) (Science Applications International Corp., McLean, VA (USA). Foreign Applied Sciences Assessment Center); Klinger, A. (California Univ., Los Angeles, CA (USA). Dept. of Computer Science); Aggarwal, J.K. (Texas Univ., Austin, TX (USA)); George, N.J. (Rochester Univ., NY (USA). Inst. of Optics); Haralick, R.M. (Washington Univ., Seattle, WA (USA). Dept. of Electric

1989-12-01

13

Imaging the debris cloud around Sakurai's object  

NASA Astrophysics Data System (ADS)

Stellar evolution models predict a common but brief post-AGB episode of helium shell burning as the remnants of low mass stars enter the white dwarf sequence. Over the last century two nearly identical final flash events have been observed. The most recent and by far the best studied was of Sakurai's object=V4334 Sgr. Sakurai's object returned to AGB luminosity in 1995 and was obscured in a dust cloud of its own making by 1999. Using NIRI plus Altair we tentatively imaged the ejecta in 2010. We propose to confirm this detection. Images of the ejecta reveal the mass loss geometry and allow direct measurement of the nebular expansion. Observations of other final flash objects strongly disagree with standard predictions. Imaging the mass loss geometry and setting a distance to Sakurai from the expansion of the nebula will provide significant constraints on theory.

Hinkle, Kenneth; Joyce, Richard

2013-02-01

14

Cloud patterns lee of Hawaii Island: A synthesis of satellite observations and numerical simulation  

E-print Network

Cloud patterns lee of Hawaii Island: A synthesis of satellite observations and numerical simulation on lee cloud formation during summer. Over the island, the cloud distribution is consistent cloud production in the upward motion. Such an offshore cloud band is not found off the northwest coast

Xie, Shang-Ping

15

Cloud Imagers Offer New Details on Earth's Health  

NASA Technical Reports Server (NTRS)

A stunning red sunset or purple sunrise is an aesthetic treat with a scientific explanation: The colors are a direct result of the absorption or reflectance of solar radiation by atmospheric aerosols, minute particles (either solid or liquid) in the Earth s atmosphere that occur both naturally and because of human activity. At the beginning or end of the day, the Sun s rays travel farther through the atmosphere to reach an observer s eyes and more green and yellow light is scattered, making the Sun appear red. Sunset and sunrise are especially colorful when the concentration of atmospheric particles is high. This ability of aerosols to absorb and reflect sunlight is not just pretty; it also determines the amount of radiation and heat that reaches the Earth s surface, and can profoundly affect climate. In the atmosphere, aerosols are also important as nuclei for the condensation of water droplets and ice crystals. Clouds with fewer aerosols cannot form as many water droplets (called cloud particles), and consequently, do not scatter light well. In this case, more sunlight reaches the Earth s surface. When aerosol levels in clouds are high, however, more nucleation points can form small liquid water droplets. These smaller cloud particles can reflect up to 90 percent of visible radiation to space, keeping the heat from ever reaching Earth s surface. The tendency for these particles to absorb or reflect the Sun s energy - called extinction by astronomers - depends on a number of factors, including chemical composition and the humidity and temperature in the surrounding air; because cloud particles are so small, they are affected quickly by minute changes in the atmosphere. Because of this sensitivity, atmospheric scientists study cloud particles to anticipate patterns and shifts in climate. Until recently, NASA s study of atmospheric aerosols and cloud particles has been focused primarily on satellite images, which, while granting large-scale atmospheric analysis, limited scientists ability to acquire detailed information about individual particles. Now, experiments with specialized equipment can be flown on standard jets, making it possible for researchers to monitor and more accurately anticipate changes in Earth s atmosphere and weather patterns.

2009-01-01

16

Clouds and cloud shadows removal from high-resolution remote sensing images  

Microsoft Academic Search

In the remote sensing images recorded by high- resolution optical sensors such as SPOT, TM, IKONOS, QUICKBIRD etc., clouds and cloud shadows may unfortunately contaminate the scene. Removing these portions of an image and then filling in the missing data is an important photo editing work. Traditionally the operators have to mask them out from the scene, and cut a

Fen Chen; Zhongming Zhao; Ling Peng; Dongmei Yan

2005-01-01

17

Cloud base height survey based on stereo image  

NASA Astrophysics Data System (ADS)

Cloud observation is an important factor for weather application and change of cloud base height plays a vital role in development of future weather system. Aim at requirement of cloud observation, a method on survey of cloud base height (CBH) is proposed based on stereo image. The main contents include image match and calculation of CBH which makes use of forward intersection of photogrammetry. It overcomes discontinuity, strong subjectivity and qualitative analysis of traditional eye observation. By application of National Day's weather safeguard, it tests that method of stereo imaging surveying is a way of direct measurement with better precision and is possible in technology also.

Li, Guosheng; Lin, Zongjian; Ma, Shuqing; Zhi, Xiaodong

2011-06-01

18

The characterization of particle clouds using optical imaging techniques  

E-print Network

Optical imaging techniques can be used to provide a better understanding of the physical properties of particle clouds. The purpose of this thesis is to design, perform and evaluate a set of experiments using optical imaging ...

Bruce, Elizabeth J. (Elizabeth Jane), 1972-

1998-01-01

19

Edge detection of images based on cloud model cellular automata  

Microsoft Academic Search

In order to resolve the problems of edge detection algorithm of images based on fuzzy seasoning or cellular automata, a new improved edge detection algorithm of images based on cloud model cellular automata is presented. This method uses direction information and edge order information as edge characteristic information, uses cloud model to inference these information, then gives accurate feedback information

Zhang Ke; Zhang Weihua; Yuan Jinsha

2008-01-01

20

Cloud classification using whole-sky imager data  

SciTech Connect

Clouds are one of the most important moderators of the earth radiation budget and one of the least understood. The effect that clouds have on the reflection and absorption of solar and terrestrial radiation is strongly influenced by their shape, size, and composition. Physically accurate parameterization of clouds is necessary for any general circulation model (GCM) to yield meaningful results. The work presented here is part of a larger project that is aimed at producing realistic three-dimensional (3D) volume renderings of cloud scenes, thereby providing the important shape information for parameterizing GCMs. The specific goal of the current study is to develop an algorithm that automatically classifies (by cloud type) the clouds observed in the scene. This information will assist the volume rendering program in determining the shape of the cloud. Much work has been done on cloud classification using multispectral satellite images. Most of these references use some kind of texture measure to distinguish the different cloud types and some also use topological features (such as cloud/sky connectivity or total number of clouds). A wide variety of classification methods has been used, including neural networks, various types of clustering, and thresholding. The work presented here utilizes binary decision trees to distinguish the different cloud types based on cloud feature vectors.

Buch, K.A. Jr.; Sun, Chen-Hui

1995-02-01

21

Radiometric cloud imaging with an uncooled microbolometer thermal infrared camera.  

PubMed

An uncooled microbolometer-array thermal infrared camera has been incorporated into a remote sensing system for radiometric sky imaging. The radiometric calibration is validated and improved through direct comparison with spectrally integrated data from the Atmospheric Emitted Radiance Interferometer (AERI). With the improved calibration, the Infrared Cloud Imager (ICI) system routinely obtains sky images with radiometric uncertainty less than 0.5 W/(m(2 )sr) for extended deployments in challenging field environments. We demonstrate the infrared cloud imaging technique with still and time-lapse imagery of clear and cloudy skies, including stratus, cirrus, and wave clouds. PMID:19498585

Shaw, Joseph; Nugent, Paul; Pust, Nathan; Thurairajah, Brentha; Mizutani, Kohei

2005-07-25

22

Data and image fusion for geometrical cloud characterization  

SciTech Connect

Clouds have a strong influence on the Earth`s climate and therefore on climate change. An important step in improving the accuracy of models that predict global climate change, general circulation models, is improving the parameterization of clouds and cloud-radiation interactions. Improvements in the next generation models will likely include the effect of cloud geometry on the cloud-radiation parameterizations. We have developed and report here methods for characterizing the geometrical features and three-dimensional properties of clouds that could be of significant value in developing these new parameterizations. We developed and report here a means of generating and imaging synthetic clouds which we used to test our characterization algorithms; a method for using Taylor`s hypotheses to infer spatial averages from temporal averages of cloud properties; a computer method for automatically classifying cloud types in an image; and a method for producing numerical three-dimensional renderings of cloud fields based on the fusion of ground-based and satellite images together with meteorological data.

Thorne, L.R.; Buch, K.A.; Sun, Chen-Hui; Diegert, C.

1997-04-01

23

A Light-Weight Solution to Preservation of Access Pattern Privacy in Un-trusted Clouds  

E-print Network

A Light-Weight Solution to Preservation of Access Pattern Privacy in Un-trusted Clouds Ka Yang information, etc.) have been centralized into the cloud, cloud computing is facing great privacy and security,alexzjs,wzhang,daji}@iastate.edu Abstract. Cloud computing is a new computing paradigm that is gaining in- creased popularity. More and more

Qiao, Daji

24

Cloud morphology and motions from Pioneer Venus images  

NASA Technical Reports Server (NTRS)

The horizontal and vertical cloud structures, atmospheric waves, and wind velocities at the cloud top level were determined by the Pioneer Venus photopolarimeter images in the UV from January through March 1979. The images indicate long-term evolution of cloud characteristics, the atmospheric dynamics, and rapid small changes in cloud morphology. The clouds show a globally coordinated oscillation relative to latitude circles; retrograde zonal winds of 100 m/s near the equator are determined from the tracking of small-scale cloud properties, but two hemispheres show important variations. The zonal wind velocity in the southern hemisphere is reduced toward the poles at a rate similar to solid body rotation; the midlatitude jet stream noted by Mariner 10 is not observed.

Rossow, W. B.; Del Genio, A. D.; Limaye, S. S.; Travis, L. D.; Stone, P. H.

1980-01-01

25

BTC image coding with visual patterns  

Microsoft Academic Search

This paper presents a block truncation coding (BTC) scheme for image compression that employs visual patterns designed independently of the image to be coded. In this method, image blocks are first classified into three classes: uniform, gentle edge, and sharp edge, according to their variations. Design focus is on edge blocks, where two sets of patterns, namely, visual patterns and

Tak Po Chan; Bing Zeng; Ming L. Liou

1994-01-01

26

Pattern-selective color image fusion  

Microsoft Academic Search

This paper introduces pattern-selective color image fusion and shows how it can be applied to two domains of image enhancement: extension of dynamic range and depth of focus. Pattern-selective fusion methods provide a mechanism for combining multiple monochromatic source images through identifying salient features in the source images at multiple scales and orientations, and combining those features into a single

Luca Bogoni; Michael W. Hansen

2001-01-01

27

The use of shape, appearance and the dynamics of clouds for satellite image interpretation  

Microsoft Academic Search

Atmospheric processes are manifested through the formation and dispersal of clouds and cloud patterns. Consequently, clouds are of great importance to weather forecasting. The ability to study cloud patterns over wide areas and in regions where meteorological data is sparse has led to the development of subjective techniques, that use conceptual models, to analyse the cloud cover contained in satellite

Hugh G. Lewis

1998-01-01

28

Clouds  

NSDL National Science Digital Library

In this scenario-based, problem-based learning (PBL) activity, students investigate cloud formation, cloud classification, and the role of clouds in heating and cooling the Earth; how to interpret TRMM (Tropical Rainfall Measuring Mission) images and data; and the role clouds play in the Earthâs radiant budget and climate. Students assume the role of weather interns in a state climatology office and assist a frustrated student in a homework assignment. Learning is supported by a cloud in a bottle and an ice-albedo demonstration, a three-day cloud monitoring outdoor activity, and student journal assignments. The hands-on activities require two 2-liter soda bottles, an infrared heat lamp, and two thermometers. The resource includes a teacher's guide, questions and answer key, assessment rubric, glossary, and an appendix with information supporting PBL in the classroom.

29

Algorithms for Moderate Resolution Imaging Spectroradiometer cloud-free image compositing  

NASA Astrophysics Data System (ADS)

The presence of clouds is the biggest obstacle in the investigation of land cover, and many techniques have been developed to detect clouds. However, few indicators have been proposed for the detection of cloud-free conditions. To address this, we propose two indicators for use in compositing 8-day cloud-free images: the B ratio is the ratio of the band 1 reflectance to the band 7 reflectance of Terra surface reflectance images (MOD09GA), and saturation refers to the color saturation of these images. Here, we describe the principles underlying these two indicators and analyze their characteristics for vegetation, water, urban, and nonvegetation pixels under cloud-free, cloud shadow, and cloudy conditions using MOD09GA from October 16 to 23, 2007, in North China (sample A) and using data published by the U.S. Geological Survey (USGS). We found that the B ratio and saturation are suitable for extracting cloud-free pixels over land and water, respectively; therefore, we combined these two indicators to develop a single-unified model. In particular, our results demonstrate that the pixels exhibiting the lowest B ratios should be adopted as cloud-free pixels over land when the value of B for land surfaces is between 0 and 1, and the surface reflectance of Moderate Resolution Imaging Spectroradiometer band 1 is less than 0.3. Otherwise, the pixels exhibiting the greatest saturation values should be adopted. We used our model to composite cloud-free images for two additional regions in China: the Tarim basin (sample B) from October 2 to 9, 2012, and the coastal areas of southeastern China (sample C) from April 15 to 23, 2013. We compared the cloud-free images of these regions with the 8-day surface reflectance product (MOD09A1) with respect to clouds, cloud shadow, and cirrus clouds, and we found that our proposed cloud-free image compositing approach can accurately eliminate both clouds and cirrus clouds. Specifically, the percentage of residual cloud pixels in sample C was found to be less than that in MOD09A1. Moreover, in the cloud-free images obtained using our newly developed method, cloud-free pixels are typically associated with greater sensor zenith angles and smaller scatter angles than those in MOD09A1. However, our method retains some limitations. In particular, 9.68, 33.22, and 33.00% of cloud-shadow pixels remain in the cloud-free images for samples A, B, and C, respectively.

Xiang, Hai-bing; Liu, Jin-song; Cao, Chun-xiang; Xu, Min

2013-01-01

30

Hazardous cloud imaging: a new way of using passive infrared  

NASA Astrophysics Data System (ADS)

A modeling and simulation study of the limits of remote detection by passive IR has led to a new concept for the remote detection of hazardous clouds. A passive IR signature model was developed with the Edgewood Research, Development, and Engineering Center IR spectral data bases used as input for chemicals and biologicals and with the atmospheric transmittance model used for Modtran . The cloud travel and dispersion model, VLStrack , was used to simulate chemical and biological clouds. An easily applied spectral discrimination technique was developed with a standard Mathematica version of linear programming. All these were melded with Mathematica to produce images of three threat clouds: Sarin, mustard, and an unnamed biological. The hazardous cloud imager is a spatially scanning Fourier transform IR on the same level of complexity as conventional remote detectors, but is capable of greater sensitivity and moving operation.

Flanigan, Dennis F.

1997-09-01

31

Patchy Clouds and Rotation Periods in Directly Imaged Exoplanets  

NASA Astrophysics Data System (ADS)

Directly imaged exoplanets offer unique insights into weakly-irradiated planetary atmospheres and into the architecture of outer planetary systems. They also raise two pivotal questions: 1} How do their atmospheres compare to brown dwarfs? and 2} How did these large-separation massive planets form? Atmospheric modeling of directly imaged planets is complicated by the presence of condensate clouds; many successful models assume patchy cloud cover, a combination of two different atmospheres {e.g. cloudy and cloud-free}. Heterogeneous cloud covers are common in brown dwarfs and lead to rotational photometric variability. In addition, different planet formation models proposed for large-separation exoplanets lead to different typical rotation rates. We pioneered HST and Spitzer rotational mapping of brown dwarfs and in a series of studies showed that this technique provides very important and unique constraints on the composition and structure of brown dwarf atmospheres and their cloud layers. We propose here to apply high-contrast, high-precision photometry to two prototypical directly imaged exoplanets {or planetary mass companions} and search for photometric variations. The observations will: 1} verify the prediction of patchy cloud cover and allow quantitative comparisons to cloud properties observed in brown dwarfs; and, 2} provide the first direct measurements of the rotation periods of wide-separation exoplanets, an important constraint on their formation mechanism. Furthermore, the proposed observations will demonstrate a new observing technique on two low-risk targets, opening a new window on directly imaged exoplanets.

Apai, Daniel

2013-10-01

32

The qualitative analyses of cloud cover on optical satellite image  

NASA Astrophysics Data System (ADS)

The remote sensing technology has become the important information source in environment investigation, Moreover, optical satellite images are the most important information source. Although the optical satellite images may provides high resolution, multi-spectral images and better vision images than active satellite, the disadvantage is affected by the atmospheric condition easily. In general, the cloud cover is the most common noise, may decrease the image information abundantly and has impact on the environmental monitoring application seriously. According to the cloud imaging model, add defilade manually with different reflection coefficient to simulate different thickness of cloud. Then utilize GIS analytical method and cooperate with histogram calculation to extraction different reflection coefficients boundary. In this research, we get the upper threshold limitation value for haze and lower threshold limitation value for thick heavy cloud. So, we change the classification level from 2 ordinal levels into 3 qualitative levels. We change the thick and haze cover classification into threshold limitation value heavy, haze and fuzzy could cover classification by using the Formosat-2 satellite images. Make use of therefore way, can change the description yardstick into the quantitative yardstick that is we change the ordinal scale into interval scale in the image of cloud cover efficiency.

Liu, Chih-Heng; Yeh, Mei-Ling; Chou, Tine-Yin; Yang, Lung-Shih

2008-10-01

33

Hazardous cloud imaging: a new way of using passive IR  

NASA Astrophysics Data System (ADS)

A Modeling and Simulation study of the limits of remote detection by passive IR has led to a new concept for the remote detection of hazardous clouds. A passive IR signature model was developed using as input the ERDEC IR spectral data bases for chemicals and biologicals, and the atmospheric transmittance model MODTRAN (MODerate resolution TRANSmittance). The cloud travel and dispersion model VLSTRACK (Vapor, Liquid, and Solid TRACKing) was used to simulate chemical and biological clouds. An easily applied spectral discrimination technique was developed using Linear Programming. All of these were melded with MATHEMATICA to produce images of 3 threat clouds: Sarin, mustard and an unnamed biological. (For reasons of space only Sarin is discussed here.) The HAZCI (HAZarous Cloud Imager) is a unique configuration of a spatially scanning Fourier Transform IR on the same level of complexity as the M21, but capable of orders-of-magnitude greater sensitivity and moving operation. The concept provides for automatic detection and operator assisted discrimination for chemical clouds and biological clouds at ranges greater than 50 kms. Both chemical and biological clouds can generally be discriminated from other known battlefield contaminants and from all materials (including biologicals) that are uniformly distributed in the atmosphere; but, specific detection of pathogenic biologicals is not projected at this time.

Flanigan, Dennis F.

1997-07-01

34

Ultraviolet Imaging Polarimetry of the Large Magellanic Cloud. II. Models  

E-print Network

Motivated by new sounding-rocket wide-field polarimetric images of the Large Magellanic Cloud, we have used a three-dimensional Monte Carlo radiation transfer code to investigate the escape of near-ultraviolet photons from young stellar associations embedded within a disk of dusty material (i.e. a galaxy). As photons propagate through the disk, they may be scattered or absorbed by dust. Scattered photons are polarized and tracked until they escape to be observed; absorbed photons heat the dust, which radiates isotropically in the far-infrared, where the galaxy is optically thin. The code produces four output images: near- UV and far-IR flux, and near-UV images in the linear Stokes parameters Q and U. From these images we construct simulated UV polarization maps of the LMC. We use these maps to place constraints on the star + dust geometry of the LMC and the optical properties of its dust grains. By tuning the model input parameters to produce maps that match the observed polarization maps, we derive information about the inclination of the LMC disk to the plane of the sky, and about the scattering phase function g. We compute a grid of models with i = 28 deg., 36 deg., and 45 deg., and g = 0.64, 0.70, 0.77, 0.83, and 0.90. The model which best reproduces the observed polarization maps has i = 36 +2/-5 degrees and g ~0.7. Because of the low signal-to-noise in the data, we cannot place firm constraints on the value of g. The highly inclined models do not match the observed centro-symmetric polarization patterns around bright OB associations, or the distribution of polarization values. Our models approximately reproduce the observed ultraviolet photopolarimetry of the western side of the LMC; however, the output images depend on many input parameters and are nonunique.

Andrew A. Cole; Kenneth Wood; Kenneth H. Nordsieck

1999-09-08

35

Spatial Cloud Detection and Retrieval System for Satellite Images  

Microsoft Academic Search

In last the decade we witnessed a large increase in data generated by earth observing satellites. Hence, intelligent processing of the huge amount of data received by hundreds of earth receiving stations, with specific satellite image oriented approaches, presents itself as a pressing need. One of the most important steps in earlier stages of satellite image processing is cloud detection.

Noureldin Laban; Ayman Nasr; Alf Maskan; Motaz ElSaban; Hoda Onsi

2012-01-01

36

Automated detection and removal of cloud shadows on HICO images  

NASA Astrophysics Data System (ADS)

Clouds cause a serious problem for optical satellite sensors. Clouds not only conceal the ground, they also cast shadows, which cause either a reduction or total loss of information in an image, by reducing the illumination falling on the shadowed pixels. Ocean color bio-optical inversion algorithms rely on measurements of remote sensing reflectance (Rrs (? )) at each pixel. If shadows are not removed properly across a scene, erroneous Rrs (?) values will be calculated for the shadowed pixels, leading to incorrect retrievals of ocean color products such as chlorophyll. The cloud shadow issue becomes significant especially for high-resolution sensors such as the Hyperspectral Imager for the Coastal Ocean (HICO). On the other hand, the contrast of pixels in and outside a shadow provides opportunities to remove atmospheric contributions for ocean color remote sensing. Although identifying cloud is relatively straightforward using simple brightness thresholds, identifying their shadows especially over water is quite challenging because the brightness of the shadows is very close to the brightness of neighboring sunny regions especially in deep waters. In this study, we present automated procedures for our recently proposed cloud shadow detection technique called the Cloud Shadow Algorithm (CSA) and Lee et al. (2007) cloud and shadow atmospheric correction algorithm. We apply both automated procedures to HICO imagery and show examples of the results.

Amin, Ruhul; Gould, Richard; Hou, Weilin; Lee, Zhongping; Arnone, Robert

2011-06-01

37

Two-Dimensional Hydrometeor Image Classification by Statistical Pattern Recognition Algorithms  

Microsoft Academic Search

The investigation reported here involves the automatic classification of binary (black and white) images of hydrometeors (ice particles and raindrops) taken from cloud samples. The goal is to classify such images (both complete and fractional) into the seven most common classes of hydrometeors by statistical pattern recognition techniques. Detailed investigation about the data acquisition system and preprocessing is made. Four

Mizanur M. Rahman; Raymond G. Jacquot; Edmund A. Quincy; Ronald E. Stewart

1981-01-01

38

Images from Galileo of the Venus cloud deck  

USGS Publications Warehouse

Images of Venus taken at 418 (violet) and 986 [near-infrared (NIR)] nanometers show that the morphology and motions of large-scale features change with depth in the cloud deck. Poleward meridional velocities, seen in both spectral regions, are much reduced in the NIR. In the south polar region the markings in the two wavelength bands are strongly anticorrelated. The images follow the changing state of the upper cloud layer downwind of the subsolar point, and the zonal flow field shows a longitudinal periodicity that may be coupled to the formation of large-scale planetary waves. No optical lightning was detected.

Belton, M.J.S.; Gierasch, P.J.; Smith, M.D.; Helfenstein, P.; Schinder, P.J.; Pollack, J.B.; Rages, K.A.; Ingersoll, A.P.; Klaasen, K.P.; Veverka, J.; Anger, C.D.; Carr, M.H.; Chapman, C.R.; Davies, M.E.; Fanale, F.P.; Greeley, R.; Greenberg, R.; Head, J. W., III; Morrison, D.; Neukum, G.; Pilcher, C.B.

1991-01-01

39

Segmentation for Satellite Cloud Image by Combining Fractal Features and Continuous Wavelet Transform  

Microsoft Academic Search

A kind of algorithm to segment typhoon cloud image is proposed. First, fractal feature of typhoon cloud image is used to recognize center dense cloud region so that an initial segmentation region (ISR) including typhoon cloud series can be determined. Morphological operator and median filter are used to reduce latitude lines and amplitude lines in the ISR so as to

Changjiang Zhang; Juan Lu; Sufang Shu

2009-01-01

40

Designing SCIT Architecture Pattern in a Cloud-based Environment  

E-print Network

C-SCIT (Cloud- based Self-Cleansing Intrusion Tolerant) scheme that can provide enhanced intrusion. The main contribution of this paper is to design a Cloud- based Self-Cleansing Intrusion Tolerance (C

Sood, Arun K.

41

Jupiter's Cloud Structure from Galileo Imaging Data  

Microsoft Academic Search

The vertical structure of aerosols on Jupiter is inferred from data obtained by the NASA Galileo Solid State Imaging system during the first six orbits of the spacecraft. Images at 889 nm (a strong methane band), 727 nm (a weaker methane band), and 756 nm (continuum) taken at a variety of lighting and viewing angles are used. The images are

D. Banfield; P. J. Gierasch; M. Bell; E. Ustinov; A. P. Ingersoll; A. R. Vasavada; Robert A. West; M. J. S. Belton

1998-01-01

42

Describing the NPOESS Preparatory Project Visible/Infrared Imaging Radiometer Suite (VIIRS) Cloud Environmental Data Records  

NASA Astrophysics Data System (ADS)

The Visible/Infrared Imaging Radiometer Suite (VIIRS) is one of the instruments that make up the suite of sensors on the NPOESS Preparatory Project (NPP) scheduled to launch in 2010. VIIRS will produce seven Environmental Data Records (EDRs) describing cloud properties. The VIIRS Cloud EDRs include the Cloud Optical Thickness (COT), Cloud Effective Particle Size Parameter (CEPS), Cloud Top Pressure (CTP), Cloud Top Height (CTH), Cloud Top Temperature (CTT), Cloud Cover/Layers (CCL), and Cloud Base Height (CBH). This paper will describe the VIIRS algorithms used to generate these EDRs and provide a current estimate of performance based on pre-Launch test data.

Hoffman, C.; Guenther, B.; Kilcoyne, H.; Mineart, G.; St. Germain, K.; Reed, B.

2008-12-01

43

Enhanced IR imagery of cloud top temperatures, heights, cloud types and organizational patterns  

NSDL National Science Digital Library

Dorothea Ivanova, Embry-Riddle Aeronautical University Summary The object of this activity is to find enhanced IR imagery, to interpret cloud top temperatures and heights and to identify cloud types and ...

Ivanova, Dorothea

44

Cloud Detection with the Earth Polychromatic Imaging Camera (EPIC)  

NASA Technical Reports Server (NTRS)

The Earth Polychromatic Imaging Camera (EPIC) on board the Deep Space Climate Observatory (DSCOVR) would provide a unique opportunity for Earth and atmospheric research due not only to its Lagrange point sun-synchronous orbit, but also to the potential for synergistic use of spectral channels in both the UV and visible spectrum. As a prerequisite for most applications, the ability to detect the presence of clouds in a given field of view, known as cloud masking, is of utmost importance. It serves to determine both the potential for cloud contamination in clear-sky applications (e.g., land surface products and aerosol retrievals) and clear-sky contamination in cloud applications (e.g., cloud height and property retrievals). To this end, a preliminary cloud mask algorithm has been developed for EPIC that applies thresholds to reflected UV and visible radiances, as well as to reflected radiance ratios. This algorithm has been tested with simulated EPIC radiances over both land and ocean scenes, with satisfactory results. These test results, as well as algorithm sensitivity to potential instrument uncertainties, will be presented.

Meyer, Kerry; Marshak, Alexander; Lyapustin, Alexei; Torres, Omar; Wang, Yugie

2011-01-01

45

New Cloud Detection Algorithm for Multispectral and Hyperspectral Images: Application to  

E-print Network

New Cloud Detection Algorithm for Multispectral and Hyperspectral Images: Application to ENVISAT that faces the problem of accurate identification of location and abundance of clouds in multispectral images inevitable that many of these images present cloud covers. The objective of this work is to develop

Camps-Valls, Gustavo

46

Watershed image segmentation and cloud classification from multispectral MSG-SEVIRI imagery.  

NASA Astrophysics Data System (ADS)

Clouds play an important role in the Earth's climate system, modulating the radiative energy budget. Consequently, a good knowledge of their radiative properties and of the spatial and temporal distribution of cloud cover is necessary. Earth observation satellites provide us with long time-series data on a global scale and they have become essential tools for the continuous monitoring of cloud properties. Thus, for example, ISCCP (International Satellite Cloud Climatology Project), ERBE (Earth Radiation Budget Experiment) or CERES (Clouds and the Earth s Radiant Energy System) projects have provided essential datasets to improve our understanding of the effects of atmospheric cloud radiative forcing on climate. The problem of cloud segmentation and classification from multispectral satellite imagery is considered in this work. Many methods, based on both supervised and unsupervised classi- fication, have been developed previously, but most of them are based on independent pixel processing. In this study, a segmentation algorithm is applied as a first step, in order to get a partition of the original image into a set of meaningful objects. This segmentation is performed through order-invariant watershed algorithms, based on immersion and toboggan approaches. The multi-scale gradient magnitude has been obtained using a multi-resolution morphological operator from spectral data and texture information, computed through fractal and local binary patterns (LBP) methods. To reduce the oversegmentation produced by the watershed technique, a fast region merging is applied, using region dissimilarity functions that takes into account internal and boundary features.Once the objects present in the image have been segmented, they are classified using a multi-threshold classification method based on physical considerations and radiative and texture features. The proposed technique is applied to MSG-SEVIRI multispectral data, including both daylight and nighttime images. This radiometer provides high quality images, every 15 minutes, with 3km resolution at nadir in 11 spectral bands, covering from visible to thermal infrared region. The optimal sets of spectral bands and texture features to obtain good segmentation and classification results are studied. Classification results are evaluated using different ground true data: MODIS cloud products, SAFNWC/MSG SEVIRI cloud data and manual human expert classification based on the visual inspection and other related information. Furthermore, the influence of spatial resolution has been investigated.

González, Albano; Mendez, Zebensui; Munoz, Jonathan; Perez, Juan C.; Armas Padilla, Montserrat

47

Fringe pattern denoising via image decomposition.  

PubMed

Filtering off noise from a fringe pattern is one of the key tasks in optical interferometry. In this Letter, using some suitable function spaces to model different components of a fringe pattern, we propose a new fringe pattern denoising method based on image decomposition. In our method, a fringe image is divided into three parts: low-frequency fringe, high-frequency fringe, and noise, which are processed in different spaces. An adaptive threshold in wavelet shrinkage involved in this algorithm improves its denoising performance. Simulation and experimental results show that our algorithm obtains smooth and clean fringes with different frequencies while preserving fringe features effectively. PMID:22297373

Fu, Shujun; Zhang, Caiming

2012-02-01

48

Global Patterns of Cloud Optical Thickness Variation with Temperature and the Implications for Climate Change.  

NASA Astrophysics Data System (ADS)

This thesis presents a correlative analysis of cloud optical thickness and cloud temperature in large space and time scales. The analysis is designed to document and explain the patterns of cloud optical thickness variation with temperature, and to produce an understanding of cloud optical property feedbacks on climate change. The results of the global correlations between cloud optical thickness and temperature are presented in Chapter I. The analysis focuses on low clouds to limit variations in cloud vertical extent, particle size and water phase. Coherent patterns of change are observed on several time and space scales. On the planetary and the seasonal scales, clouds in the colder latitudes and seasons are found to be optically thicker than clouds in the warmer latitudes and seasons. The seasonal, latitudinal, and day-to-day variations of this relation show that in cold continental clouds optical thickness increases with temperature consistent with the temperature variation of the adiabatic cloud water content, but in warm continental and in most maritime clouds optical thickness decreases with temperature. In Chapter II, a number of case studies are presented that attempt to identify the cloud parameters responsible for the optical thickness changes and to resolve the atmospheric processes that produce those changes. It is found that the temperature variation of low cloud optical thickness primarily reflect changes in the liquid water content of the clouds, and that changes in cloud particle size and vertical extent play a secondary role. In continental clouds, the optical thickness-temperature relation changes from a positive to a negative slope at the same temperature range that the percentage of precipitating clouds shows a marked increase. It is proposed that an increase in the efficiency of formation of warm rain at higher temperatures relative to condensation, raises the probability of occurrence of optically thin clouds at warmer temperatures and produces the observed negative optical thickness slopes. In Chapter III, a two dimensional radiative convective model is used to estimate the magnitude and sign of the feedback that the observed cloud optical thickness changes would produce in a climate warming scenario. A positive feedback is derived that increases the predicted 2 times CO_2 warming by 1.5^circC in the subtropics and by 0.5^circC in the midlatitudes of the Northern Hemisphere. The latitudinal contrast in the strength of the feedback acts to negate the high latitude amplification of the greenhouse warming.

Tselioudis, George

1992-01-01

49

A Measurement Study of Data-intensive Network Traffic Patterns in a Private Cloud  

E-print Network

A Measurement Study of Data-intensive Network Traffic Patterns in a Private Cloud Daniele Venzano. In this work, we study the performance � from the network- ing perspective � that private cloud deployments Framework, or OSMeF), described in section IV, we studied the behaviour of virtual and physical networks

Michiardi, Pietro

50

Skeleton/Pattern Programming with an Adder Operator for Grid and Cloud Platforms  

E-print Network

Skeleton/Pattern Programming with an Adder Operator for Grid and Cloud Platforms J. Villalobos, B-- Pattern operators are extensions to the Pat- tern/Skeleton parallel programming approach used to apply two of possi- ble patterns and skeletons. The abstraction helps manage non-functional concerns on the Grid

Wilkinson, Barry

51

Patterns of shallow clouds and rainfall over the Amazon : climatic impacts of deforestation  

E-print Network

(cont.) and, to a lesser extent, cold cloud patterns over the Amazon. Through complex interactions, the results reported in this thesis may have important implications for the local ecosystem dynamics of the Amazon, for ...

Chagnon, Frédéric J. F. (Frédéric Jacques F.), 1975-

2005-01-01

52

CloudSat Image of a Polar Night Storm Near Antarctica  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Figure 1

CloudSat image of a horizontal cross-section of a polar night storm near Antarctica. Until now, clouds have been hard to observe in polar regions using remote sensing, particularly during the polar winter or night season. The red colors are indicative of highly reflective particles such as water (rain) or ice crystals, while the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudSat Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The blue line below the Cloud Profiling Radar image indicates that the data were taken over water; the brown line below the image indicates the relative elevation of the land surface. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) infrared image taken at nearly the same time.

2006-01-01

53

Tiros III cloud distributions and vorticity patterns over the southeastern United States and adjacent water area  

E-print Network

TIROS III CLOUD DISTRIBUTIONS AND VORTICITY PATTERNS OVER THE SOUTHEASTERN UNITED STATES AND ADJACENT WATER AREA A Thesis By Graham Ellis Abbott Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial... fulfillment of the requirements for the degree of MASTER OF SCIENCE August 1963 Major Subject: METEOROLOGY TIROS III CLOUD DISTRIBUTIONS AND VORTICITY PATTERNS OVER THE SOUTHEASTERN UNITED STATES AND ADJACENT WATER AREA A Thesis By Graham Ellis Abbott...

Abbott, Graham Ellis

2012-06-07

54

The pericardial effusion pattern on phase images  

SciTech Connect

The effect of pericardial effusion on phase images of gated studies was investigated. Twenty-six patients with suspected or known pericardial effusion were correlated with echocardiography and/or clinical and other laboratory data to ascertain the presence and size of effusion. The phase image pattern and parameters were compared to the results previously obtained in seven normal patients, and in 26 patients with documented regional wall motion abnormalities but no evidence of pericardial effusion. The phase pattern was graded into five categories: typical (IV) (wide histogram, well defined concentric convex pattern, progressive delay toward the inferolateral area, identifiable also over the right ventricle); less pronounced (III); atypical (II); ill defined changes (I); and normal (0). Results: Group L (large pericardial effusion): four of six had pattern (IV) and the left ventricular histogram showed abnormal parameters. These patients had large free effusions in the pericardial sac and none had regional wall motion abnormalities. Two of six had pattern (III) and (II) but also had ancillary pericardial pathology and/or decreased ejection fraction. Group M (moderate pericardial effusion), S (small pericardial effusion), and A (absent pericardial effusion, but not normal) had variable phase images and numeric parameters. After therapeutic drainage of pericardial fluid two patients changed pattern from IV and III to 0 and a third from III to I. Category IV pattern is 100% specific for pericardial effusion; the combination of category IV or III is 87.5% specific and 61% sensitive for large and moderate pericardial effusion.

Pavel, C.M.; Kahn, J.; Rich, S.; Gonzalez, P.; Turner, S.; Pavel, D.G.

1984-02-01

55

Voyager imaging of Triton's clouds and hazes  

NASA Technical Reports Server (NTRS)

Results are presented from a detailed analysis of Voyager images of Triton obtained at the highest solar phase angles; these have been fit to Mie scattering models in order to obtain the mean particle sizes, number densities, and the vertical extent of the two different scattering components of the Triton atmosphere. The 0.001-0.01 optical depths of about 0.17 micron particles are vertically distributed with scale heights of about 10 km throughout Triton. A number of properties of the haze particles in question suggest that they are composed of photochemically produced gases which have condensed in the cold lower atmosphere of Triton.

Rages, Kathy; Pollack, James B.

1992-01-01

56

CloudSat First Image of a Warm Front Storm Over the Norwegian Sea  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Figure 1

CloudSat's first image, of a warm front storm over the Norwegian Sea, was obtained on May 20, 2006. In this horizontal cross-section of clouds, warm air is seen rising over colder air as the satellite travels from right to left. The red colors are indicative of highly reflective particles such as water droplets (or rain) or larger ice crystals (or snow), while the blue indicates thinner clouds (such as cirrus). The flat green/blue lines across the bottom represent the ground signal. The vertical scale on the CloudSat Cloud Profiling Radar image is approximately 30 kilometers (19 miles). The blue line below the Cloud Profiling Radar image indicates that the data were taken over water. The inset image shows the CloudSat track relative to a Moderate Resolution Imaging Spectroradiometer (MODIS) infrared image taken at nearly the same time.

2006-01-01

57

Cloud detection in the upper troposphere-lower stratosphere region via ACE imagers: A qualitative study  

Microsoft Academic Search

Satellite-based limb occultation measurements are well suited for the detection and mapping of polar stratospheric clouds (PSCs) and cirrus clouds. Usually, cloud signatures are detected on aerosol extinction profiles. In this paper, ACE two-dimensional (2-D) imager data are used to show PSCs and cirrus clouds. Clouds can be clearly seen, with a good vertical and horizontal resolution (1 km), during

J. Dodion; D. Fussen; F. Vanhellemont; C. Bingen; N. Mateshvili; K. Gilbert; R. Skelton; D. Turnbull; S. D. McLeod; C. D. Boone; K. A. Walker; P. F. Bernath

2007-01-01

58

A Method for Compositing MODIS Satellite Images to Remove Cloud Cover  

Microsoft Academic Search

Techniques are presented for generating thermal infrared and visible composite images from cloud-free portions of MODIS (MODerate resolution Imaging Spectroradiometer) images closely spaced in time, with a focus on studies of landfast sea ice along the East Antarctic coast. Composite image inclusion criteria are based on modified MODIS EOS cloud mask product results. The compositing process places emphasis on retaining

Alexander D. Fraser; Robert A. Massom; Kelvin J. Michael

2009-01-01

59

Enabling outsourcing XDS for imaging on the public cloud.  

PubMed

Picture Archiving and Communication System (PACS) has been the main paradigm in supporting medical imaging workflows during the last decades. Despite its consolidation, the appearance of Cross-Enterprise Document Sharing for imaging (XDS-I), within IHE initiative, constitutes a great opportunity to readapt PACS workflow for inter-institutional data exchange. XDS-I provides a centralized discovery of medical imaging and associated reports. However, the centralized XDS-I actors (document registry and repository) must be deployed in a trustworthy node in order to safeguard patient privacy, data confidentiality and integrity. This paper presents XDS for Protected Imaging (XDS-p), a new approach to XDS-I that is capable of being outsourced (e.g. Cloud Computing) while maintaining privacy, confidentiality, integrity and legal concerns about patients' medical information. PMID:23920510

Ribeiro, Luís S; Rodrigues, Renato P; Costa, Carlos; Oliveira, José Luís

2013-01-01

60

Analysis of interstellar cloud structure based on IRAS images  

NASA Technical Reports Server (NTRS)

The goal of this project was to develop new tools for the analysis of the structure of densely sampled maps of interstellar star-forming regions. A particular emphasis was on the recognition and characterization of nested hierarchical structure and fractal irregularity, and their relation to the level of star formation activity. The panoramic IRAS images provided data with the required range in spatial scale, greater than a factor of 100, and in column density, greater than a factor of 50. In order to construct densely sampled column density maps of star-forming clouds, column density images of four nearby cloud complexes were constructed from IRAS data. The regions have various degrees of star formation activity, and most of them have probably not been affected much by the disruptive effects of young massive stars. The largest region, the Scorpius-Ophiuchus cloud complex, covers about 1000 square degrees (it was subdivided into a few smaller regions for analysis). Much of the work during the early part of the project focused on an 80 square degree region in the core of the Taurus complex, a well-studied region of low-mass star formation.

Scalo, John M.

1992-01-01

61

Radar Imaging of Ocean Surface Patterns  

Microsoft Academic Search

Radar imagery of ocean surface patterns is presented and discussed. The imaging radar detects changes in ocean surface backscatter and yields imagery of deepwater gravity waves, oil slicks, island shadows, internal waves, coastal waves, and other features. The results of several observations suggest that the surface irregularities behave as iostropic scatterers for a radar wavelength of 25 cm. The popular

W. E. Brown; C. Elachi; T. W. Thompson

1976-01-01

62

Automated detecting and removing cloud shadows in full-disk solar images  

NASA Astrophysics Data System (ADS)

Sky clouds affect full-disk solar observations significantly. Their shadows obscure the details of solar features in observed images. Cloud-covered images are difficult to be used for further research without pre-processing. We proposed a technique for detecting and removing cloud shadows in full-disk solar images. In the detection procedure, a two-step approach is applied: (1) identifying the deviation of a cloud-covered image from a perfect disk; (2) quantifying the cloud cover by an index that we defined in this paper. In the removal procedure, the transmittance of clouds is measured by comparing the cloud-covered image with a “Quiet Sun” that getting from a normal observation. A restored cloud-free image can be obtained after correcting the absorption by clouds. We tested the procedures using the full-disk solar H? images of the Global Oscillation Network Group (GONG), and utilized the structural similarity (SSIM) algorithm for evaluating the performance of image restoration. The results demonstrate that both procedures are significant effective, and that the cloud-covered image is restored not only in visual effect but also in intensities of solar features.

Feng, Song; Lin, Jiaben; Yang, Yunfei; Zhu, Haibo; Wang, Feng; Ji, Kaifan

2014-10-01

63

Body image and eating patterns among adolescents  

PubMed Central

Background Data on the association between body self-perception and eating patterns among adolescents are scarce. This study assessed the association between body image and eating patterns among normal-weight, overweight and obese adolescents. Methods A cross-sectional survey (n = 1231; 12–17 years old) was carried out in the Balearic Islands, Spain. Anthropometry, body image, socio-economic determinants, and food consumption were studied. Results Fifty-one percent of boys and sixty percent of girls that wished to be thinner had less than or equal to 3 eating occasions per day. Overfat girls that wish to be thinner skipped breakfast more frequently than normal-fat girls. Overfat boys and girls that wished a thinner body reported lower consumption of several food groups than normal-fat adolescents and overfat boys satisfied with their own body image (i.e. breakfast cereals, pasta and rice dishes, other oils and fats, high fat foods, soft drinks and chocolates in boys; and dairy products and chocolates in girls).A restriction of Western diet foods and energy intake was associated with a wish to be thinner among overfat adolescents. Conclusions Many overfat boys were satisfied with their body image while practically all overfat girls reported wishing a thinner body. Meal patterns and food consumption were associated with body dissatisfaction and overfat status among adolescents. PMID:24289180

2013-01-01

64

Pattern recognition of clouds and ice in polar regions  

NASA Technical Reports Server (NTRS)

The study is based on AVHRR imagery and results from Landsat high-spatial-resolution scenes. Among the textual features investigated are the gray level difference vector (GLDV), and sum and difference histogram (SADH) approaches as well as gray level run length, spatial-coherence, and spectral-histogram measures. The traditional stepwise discriminant analysis and neural-network analysis are used for the identification of 20 Arctic surface and cloud classes. A principal-component analysis and hybrid architecture employing a modularized competitive learning layer are utilized. It is pointed out that the cloud-classification accuracy comparable to that of back-propagation could be achieved with a training time two orders of magnitude faster.

Welch, R. M.; Sengupta, S. K.; Sundar, C. A.; Kuo, K. S.; Carsey, F. D.

1990-01-01

65

Characterizing Spatial Patterns of Cloud Cover And Fog Inundation in the California Channel Islands  

NASA Astrophysics Data System (ADS)

Coastal forests in Mediterranean climates are frequently covered by clouds or immersed in fog. Previous studies suggest that clouds strongly modulate forest distributions as well as carbon and water budgets in these semi-arid environments. Both low level stratocumulus cloud cover and fog can enhance the water status of vegetation along the Californian coast and the Channel Islands by reducing insolation and raising relative humidity and thus reducing evapotranspiration, while also potentially supplying water directly to the landscape from fog-drip during otherwise warm and rainless summers. While cloud cover and fog can ameliorate summer drought stress and enhance soil water budgets, they often have different spatial and temporal patterns. The resulting shifts in relative ecological importance of fog and stratus are largely unknown. The overall objective of this project was to map spatial and temporal distributions of daytime cloud cover frequency for the California Channel Islands, and to predict probabilities of surface cloud (fog) contact and immersion for these islands. Daytime cloud cover maps were generated for the northern Channel Islands using GOES satellite imagery for the years 1996-2012. To discriminate fog from stratus the base of the cloud height was constrained by using airport cloud ceiling data and topographic information. In order to observe variation in fog frequency at scales relevant to species distributions on the Channel Islands the native GOES resolution was downscaled by using radiosonde and reanalysis data. Satellite derived estimates of cloud cover and fog were correlated with field measurements of insolation, fog drip and leaf wetness on Santa Rosa and Santa Cruz islands. This enabled spatial and temporal extrapolation to understand seasonal and inter-annual variations in cloud cover frequency and fog inundation and drip and will be important for future water balance modeling, studies of coastal vegetation distributions and for better identification of locations where native vegetation restoration efforts are likely to be most successful.

Rastogi, B.; Fischer, D. T.; Williams, P.; Iacobellis, S.; McEachern, K.; Still, C. J.

2013-12-01

66

Mesoscale circulation at the upper cloud level at middle latitudes from the imaging by Venus Monitoring Camera onboard Venus Express  

NASA Astrophysics Data System (ADS)

The Venus Monitoring Camera onboard ESA Venus Express spacecraft acquired a great number of UV images (365 nm) allowing us to track the motion of cloud features at the upper cloud layer of Venus. A digital method developed to analyze correlation functions between two UV images provided wind vector fields on the Venus day side (9-16 hours local time) from the equator to high latitudes. Sizes and regions for the correlation were chosen empirically, as a trade-off of sensitivity against noise immunity and vary from 10(°) x7.5(°) to 20(°) x10(°) depending on the grid step, making this method suitable to investigate the mesoscale circulation. Previously, the digital method was used for investigation of the circulation at low latitudes and provided good agreement with manual tracking of the motion of cloud patterns. Here we present first results obtained by this method for middle latitudes (25(°) S-75(°) S) on the basis of 270 orbits. Comparing obtained vector fields with images for certain orbits, we found a relationship between morphological patterns of the cloud cover at middle latitudes and parameters of the circulation. Elongated cloud features, so-called streaks, are typical for middle latitudes, and their orientation varies over wide range. The behavior of the vector field of velocities depends on the angle between the streak and latitude circles. In the middle latitudes the average angle of the flow deviation from the zonal direction is equal to -5.6(°) ± 1(°) (the sign “-“ means the poleward flow, the standard error is given). For certain orbits, this angle varies from -15.6(°) ± 1(°) to 1.4(°) ± 1(°) . In some regions at latitudes above 60(°) S the meridional wind is equatorward in the morning. The relationship between the cloud cover morphology and circulation peculiarity can be attributed to the motion of the Y-feature in the upper cloud layer due to the super-rotation of the atmosphere.

Patsaeva, Marina; Ignatiev, Nikolay; Markiewicz, Wojciech; Khatuntsev, Igor; Titov, Dmitrij; Patsaev, Dmitry

67

Global patterns of solar influence on high cloud cover and role of sea surface temperature  

NASA Astrophysics Data System (ADS)

Climate change and global warming have become usual terms nowadays but mechanisms that could explain their causes are not understood. One of the main sources of uncertainty in climate projections is represented by clouds, which, due to various feedback, have an important influence on Earth's radiation budget. The cloud representation in General Circulation Models relies largely on constraints derived from observations. Solar impact on climate is largely unknown and some coupling mechanisms between solar and climate variability rely on the Sea Surface Temperature. We identified solar forced patterns in observed high cloud cover (HCC) based on associations with known fingerprints of the same forcing on cloud cover obtained from reanalysis data, on observed surface air temperature (SAT), sea level pressure (SLP) and sea surface temperature (SST) fields. The solar influence on HCC has maximum amplitudes over the Pacific basin, where high cloud cover anomalies are distributed in bands of alternating polarities, indicating a SST influence on high clouds through convection. The HCC structure induced by the solar cycle appears to be generated through both so-called "top-down" and "bottom-up" mechanisms of solar influence on climate. Clouds are dependent on the relative humidity which is strongly influenced by the dynamics and SST, thus we also review possible mechanisms connecting SST with clouds, solar radiation, cosmic rays, precipitations and aerosols.

Voiculescu, Mirela; Dima, Mihai; Constantin, Daniel

2014-05-01

68

The real time calculation of cloud motion in infrared image sequences using mathematical morphology operations  

Microsoft Academic Search

The real time calculation of local cloud motion may be useful in aiding the discrimination of small targets from backgrounds by infrared search and track systems. While the apparent motion of clouds in image sequences can be considered to be optical flow, the standard methods of optical flow calculation are not suited to real time calculation of cloud motion. In

R. C. Warren

1999-01-01

69

Searching for pulsars using image pattern recognition  

E-print Network

In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surv eys using image pattern recognition with deep neural nets---the PICS(Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interferences by looking for patterns from candidate. The information from each pulsar candidate is synthesized in four diagnostic plots, which consist of up to thousands pixel of image data. The AI takes these data from each candidate as its input and uses thousands of such candidates to train its $\\sim$9000 neurons. Different from other pulsar selection programs which use pre-designed patterns, the PICS AI teaches itself the salient features of different pulsars from a set of human-labeled candidates through machine learning. The deep neural networks in this AI system grant it superior ability in recognizing various types of pulsars as well as their harmonic signals. The trained AI's performance has been validated wi...

Zhu, W W; Madsen, E C; Tan, M; Stairs, I H; Brazier, A; Lazarus, P; Lynch, R; Scholz, P; Stovall, K; Random, S M; Banaszak, S; Biwer, C M; Cohen, S; Dartez, L P; Flanigan, J; Lunsford, G; Matinez, J G; Mata, A; Rohr, M; Walker, A; Allen, B; Bhat, N D R; Bogdanov, S; Camilo, F; Chatterjee, S; Cordes, J M; Crawford, F; Deneva, J S; Desvignes, G; Ferdman, R D; Hessels, J W T; Jenet, F A; Kaplan, D; Kaspi, V M; Knispel, B; Lee, K J; van Leeuwen, J; Lyne, A G; McLaughlin, M A; Spitler, L G

2014-01-01

70

Ice Cloud Optical Depth Retrievals from CRISM Multispectral Images  

NASA Astrophysics Data System (ADS)

One set of data from the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) on the Mars Reconnaissance Orbiter (MRO) is the multispectral survey that measured the visible-through-near-infrared reflectance of the entire planet of Mars at specific wavelengths. The spectral data from several sols were be combined to create multi-spectral maps of Mars. In addition, these maps can be zonally averaged to create a latitude vs season image cube of Mars. All of these image cubes can be fit using a full radiative transfer modeling in order to retrieve ice cloud optical depth—as a map for one of the particular dates, or as a latitude vs season record.To compare the data radiative transfer models, a measure of the actual surface reflectance is needed. There are several possible ways to model this, such as using a nearby region that is "close enough" or by looking at the same region at different times and assuming one of those is the actual surface reflectance. Neither of these is ideal for trying to process an entire map of data because aerosol clouds can be fairly extensive both spatially and temporally.Another technique is to assume that the surface can be modeled as a linear combination of a limited set of intrinsic spectral endmembers. A combination of Principal Component Analysis (PCA) and Target Transformation (TT) has been used to recover just such a set of spectral endmember shapes. The coefficients in the linear combination then become additional fitting parameters in the radiative transfer modeling of each map point—all parameters are adjusted until the RMS error between the model and the data is minimized. Based on previous work, the PCA of martian spectral image cubes is relatively consistent regardless of season, implying the underlying, large-scale, intrinsic traits that dominate the data variance are relatively constant. These overall PCA results can then be used to create a single set of spectral endmembers that can be used for any of the data cubes.Presented here are the results of this PCA/TT work to find the singular set of spectral endmembers and their use in recovering ice cloud optical depth from the MRO-CRISM multispectral image cubes.

Klassen, David R.

2014-11-01

71

Clouds  

NSDL National Science Digital Library

This lesson combines science, English and art to teach the students information about clouds and to encourage abstract thinking through writing and painting. Students will first read and discuss the information about clouds. Next, they will choose a type of cloud and write a composition about it. Then they do a painting of their cloud and attach their composition.

1998-01-01

72

Congruence analysis of point clouds from unstable stereo image sequences  

NASA Astrophysics Data System (ADS)

This paper deals with the correction of exterior orientation parameters of stereo image sequences over deformed free-form surfaces without control points. Such imaging situation can occur, for example, during photogrammetric car crash test recordings where onboard high-speed stereo cameras are used to measure 3D surfaces. As a result of such measurements 3D point clouds of deformed surfaces are generated for a complete stereo sequence. The first objective of this research focusses on the development and investigation of methods for the detection of corresponding spatial and temporal tie points within the stereo image sequences (by stereo image matching and 3D point tracking) that are robust enough for a reliable handling of occlusions and other disturbances that may occur. The second objective of this research is the analysis of object deformations in order to detect stable areas (congruence analysis). For this purpose a RANSAC-based method for congruence analysis has been developed. This process is based on the sequential transformation of randomly selected point groups from one epoch to another by using a 3D similarity transformation. The paper gives a detailed description of the congruence analysis. The approach has been tested successfully on synthetic and real image data.

Jepping, C.; Bethmann, F.; Luhmann, T.

2014-06-01

73

Microwave Imager Measures Sea Surface Temperature Through Clouds  

NASA Technical Reports Server (NTRS)

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

2002-01-01

74

High resolution (375 m) cloud microstructure as seen from the NPP/VIIRS Satellite imager  

NASA Astrophysics Data System (ADS)

The VIIRS (Visible Infrared Imaging Radiometer Suite) onboard the Suomi NPP (National Polar-Orbiting Partnership) satellite has improved resolution of 750 m with respect to 1000 m of the MODerate-resolution Imaging Spectroradiometer, for the channels that allow retrieving cloud microphysical parameters such as cloud drop effective radius (re). The VIIRS has also an imager with 5 channels of double resolution of 375 m, which was not designed for retrieving cloud products. A methodology for a high resolution retrieval of re and microphysical presentation of the cloud field based on the VIIRS imager was developed and evaluated with respect to MODIS in this study. The tripled microphysical resolution with respect to MODIS allows obtaining new insights for cloud aerosol interactions, especially at the smallest cloud scales, because the VIIRS imager can resolve the small convective elements that are sub-pixel for MODIS cloud products. Examples are given for new insights on ship tracks in marine stratocumulus, pollution tracks from point and diffused sources in stratocumulus and cumulus clouds over land, deep tropical convection in pristine air mass over ocean and land, tropical clouds that develop in smoke from forest fires and in heavy pollution haze over densely populated regions in southeast Asia, and for pyro-cumulonimbus clouds. It is found that the VIIRS imager provides more robust physical interpretation and refined information for cloud and aerosol microphysics as compared to MODIS, especially in the initial stage of cloud formation. VIIRS is found to identify much more full-cloudy pixels when small boundary layer convective elements are present. This, in turn, allows a better quantification of cloud aerosol interactions and impacts on precipitation forming processes.

Rosenfeld, D.; Liu, G.; Yu, X.; Zhu, Y.; Dai, J.; Xu, X.; Yue, Z.

2013-11-01

75

High-resolution (375 m) cloud microstructure as seen from the NPP/VIIRS satellite imager  

NASA Astrophysics Data System (ADS)

VIIRS (Visible Infrared Imaging Radiometer Suite), onboard the Suomi NPP (National Polar-orbiting Partnership) satellite, has an improved resolution of 750 m with respect to the 1000 m of the Moderate Resolution Imaging Spectroradiometer for the channels that allow retrieving cloud microphysical parameters such as cloud drop effective radius (re). VIIRS also has an imager with five channels of double resolution of 375 m, which was not designed for retrieving cloud products. A methodology for a high-resolution retrieval of re and microphysical presentation of the cloud field based on the VIIRS imager was developed and evaluated with respect to MODIS in this study. The tripled microphysical resolution with respect to MODIS allows obtaining new insights for cloud-aerosol interactions, especially at the smallest cloud scales, because the VIIRS imager can resolve the small convective elements that are sub-pixel for MODIS cloud products. Examples are given for new insights into ship tracks in marine stratocumulus, pollution tracks from point and diffused sources in stratocumulus and cumulus clouds over land, deep tropical convection in pristine air mass over ocean and land, tropical clouds that develop in smoke from forest fires and in heavy pollution haze over densely populated regions in southeastern Asia, and for pyro-cumulonimbus clouds. It is found that the VIIRS imager provides more robust physical interpretation and refined information for cloud and aerosol microphysics as compared to MODIS, especially in the initial stage of cloud formation. VIIRS is found to identify significantly more fully cloudy pixels when small boundary layer convective elements are present. This, in turn, allows for a better quantification of cloud-aerosol interactions and impacts on precipitation-forming processes.

Rosenfeld, D.; Liu, G.; Yu, X.; Zhu, Y.; Dai, J.; Xu, X.; Yue, Z.

2014-03-01

76

Image pattern recognition supporting interactive analysis and graphical visualization  

NASA Technical Reports Server (NTRS)

Image Pattern Recognition attempts to infer properties of the world from image data. Such capabilities are crucial for making measurements from satellite or telescope images related to Earth and space science problems. Such measurements can be the required product itself, or the measurements can be used as input to a computer graphics system for visualization purposes. At present, the field of image pattern recognition lacks a unified scientific structure for developing and evaluating image pattern recognition applications. The overall goal of this project is to begin developing such a structure. This report summarizes results of a 3-year research effort in image pattern recognition addressing the following three principal aims: (1) to create a software foundation for the research and identify image pattern recognition problems in Earth and space science; (2) to develop image measurement operations based on Artificial Visual Systems; and (3) to develop multiscale image descriptions for use in interactive image analysis.

Coggins, James M.

1992-01-01

77

A Pattern Recognition Technique for Distinguishing Surface and Cloud Types in the Polar Regions.  

NASA Astrophysics Data System (ADS)

Measurement of polar cloud cover is important because of its strong radiative influence on the energy balance of the snow and ice surface. Conventional satellite cloud detection schemes often fail in the polar regions because the visible and thermal contrasts between cloud and surface are typically small. Nevertheless, experts looking at satellite imagery can distinguish clouds from the surface by examining the textural characteristics of the scene.This paper describes an automated pattern recognition algorithm winch identities regions of various surface and cloud types at high latitudes from visible, near-infrared, and infrared AVHRR satellite data. Five spectral features give information about the magnitude of albedos and brightness temperatures, while three textural features describe the variability and `bumpiness' in a scene. The maximum likelihood decision rule is used to classify that region into one of seven surface categories or 11 cloud categories.The algorithm was able to classify 870 training samples with a skill of 84%. Eighteen hundred artificer samples created using a Monte Carlo technique were classified with a skill of 92%, which represents the theoretical limit of class separability using the given features. Both the near-infrared information and the textural information proved to be especially useful in detecting high-latitude cloudiness. The algorithm experienced some difficulty identifying thin stratus over snow and ice and thin cirrus over land and water, situations which also prove difficult for most other cloud detection schemes.When tested on AVHRR imagery from a different date, the algorithm showed a skill of 83% as verified against the analyses of three independent experts. Significant variability was encountered among the experts, underlining the need for an objective routine. This algorithm performed more accurately thin others constructed with alternate feature sets corresponding to various existing cloud detection schemes.

Ebert, Elizabeth

1987-10-01

78

The analysis of polar clouds from AVHRR satellite data using pattern recognition techniques  

NASA Technical Reports Server (NTRS)

The cloud cover in a set of summertime and wintertime AVHRR data from the Arctic and Antarctic regions was analyzed using a pattern recognition algorithm. The data were collected by the NOAA-7 satellite on 6 to 13 Jan. and 1 to 7 Jul. 1984 between 60 deg and 90 deg north and south latitude in 5 spectral channels, at the Global Area Coverage (GAC) resolution of approximately 4 km. This data embodied a Polar Cloud Pilot Data Set which was analyzed by a number of research groups as part of a polar cloud algorithm intercomparison study. This study was intended to determine whether the additional information contained in the AVHRR channels (beyond the standard visible and infrared bands on geostationary satellites) could be effectively utilized in cloud algorithms to resolve some of the cloud detection problems caused by low visible and thermal contrasts in the polar regions. The analysis described makes use of a pattern recognition algorithm which estimates the surface and cloud classification, cloud fraction, and surface and cloudy visible (channel 1) albedo and infrared (channel 4) brightness temperatures on a 2.5 x 2.5 deg latitude-longitude grid. In each grid box several spectral and textural features were computed from the calibrated pixel values in the multispectral imagery, then used to classify the region into one of eighteen surface and/or cloud types using the maximum likelihood decision rule. A slightly different version of the algorithm was used for each season and hemisphere because of differences in categories and because of the lack of visible imagery during winter. The classification of the scene is used to specify the optimal AVHRR channel for separating clear and cloudy pixels using a hybrid histogram-spatial coherence method. This method estimates values for cloud fraction, clear and cloudy albedos and brightness temperatures in each grid box. The choice of a class-dependent AVHRR channel allows for better separation of clear and cloudy pixels than does a global choice of a visible and/or infrared threshold. The classification also prevents erroneous estimates of large fractional cloudiness in areas of cloudfree snow and sea ice. The hybrid histogram-spatial coherence technique and the advantages of first classifying a scene in the polar regions are detailed. The complete Polar Cloud Pilot Data Set was analyzed and the results are presented and discussed.

Smith, William L.; Ebert, Elizabeth

1990-01-01

79

Haze and cloud cover recognition and removal for serial Landsat images  

NASA Astrophysics Data System (ADS)

In this paper, a optimized algorithm to recognize and remove hazes and clouds from remotely sensed images of Landsat MSS/TM/ETM+ over land has been proposed. This algorithm uses only the image feature to automatically recognize and remove contamination of hazes and clouds which will prevent satellite image from assessing land surface variables. The hazes and clouds can be detected on the base of the reflectance difference with the other regions, likes thermal spectrum region. Based on both fourth tasseled cap parameter and a haze optimized transformation(HOT) as a measure of haze/cloud spatial density for single Landsat MSS/TM/ETM+ image, haze and clouds can be quantitatively recognized and removed. The performance of the proposed algorithm is demonstrated experimentally. This method can be used for atmospheric corrections to improve landscape change detection.

Kong, Xiangsheng; Qian, Yonggang; Zhang, Anding

2011-12-01

80

An effective thin cloud removal procedure for visible remote sensing images  

NASA Astrophysics Data System (ADS)

Clouds are obstructions for land-surface observation, which result in the regional information being blurred or even lost. Thin clouds are transparent, and images of regions covered by thin clouds contain information about both the atmosphere and the ground. Therefore, thin cloud removal is a challenging task as the ground information is easily affected when the thin cloud removal is performed. An efficient and effective thin cloud removal method is proposed for visible remote sensing images in this paper, with the aim being to remove the thin clouds and also restore the ground information. Since thin cloud is considered as low-frequency information, the proposed method is based on the classic homomorphic filter and is executed in the frequency domain. The optimal cut-off frequency for each channel is determined semi-automatically. In order to preserve the clear pixels and ensure the high fidelity of the result, cloudy pixels are detected and handled separately. As a particular kind of low-frequency information, cloud-free water surfaces are specially treated and corrected. Since only cloudy pixels are involved in the calculation, the method is highly efficient and is suited for large remote sensing scenes. Scenes including different land-cover types were selected to validate the proposed method, and a comparison analysis with other methods was also performed. The experimental results confirm that the proposed method is effective in correcting thin cloud contaminated images while preserving the true spectral information.

Shen, Huanfeng; Li, Huifang; Qian, Yan; Zhang, Liangpei; Yuan, Qiangqiang

2014-10-01

81

Decomposition of satellite-derived images for the distinction of cloud types' features  

NASA Astrophysics Data System (ADS)

Linear filtering methods using convolution techniques are applied in computer vision, to detect spatial discontinuities in the intensity of luminance of photograph images. These techniques are based on the following principal: a pixel's neighborhood contains information about its intensity. The variation of this intensity provides some information about the distribution and the possible decomposition of the image in various features. This decomposition relies on the relative position of the pixel (edge or not) on the image. These principals, integrated into remote sensing analyses, are applied in this study to differentiate cloud morphological features representing cloud types from a thermal image product (the Cloud top temperatures) derived from polar orbit satellites' observations. This approach contrast with that of other techniques commonly used in satellite cloud classification, and based on optical or thermodynamic properties of the clouds. The interpretation of the distribution of these cloud morphological features, and their frequency is evaluated against another cloud classification method relying on cloud optical properties. The results show a relatively good match between the two classifications. Implications of these results, on the estimation of the impact of cloud shapes' variations on the recent climate are discussed.

Dim, Jules R.; Murakami, Hiroshi

2013-02-01

82

Retrieval of Cloud Cover Parameters from Multispectral Satellite Images  

Microsoft Academic Search

A technique is described for extracting cloud cover parameters from multispectral satellite radiometric measurements. Utilizing three channels (visible, 3.7 m and 11 m) from the AVHRR (Advanced Very High Resolution Radiometer) on NOAA polar orbiting satellites, it is shown that one can retrieve four parameters for each pixel: cloud fraction within the FOV, optical thickness cloud-top temperature and a microphysical

Albert Arking; Jeffrey D. Childs

1985-01-01

83

Investigation of vortex clouds and droplet sizes in heated water spray patterns generated by axisymmetric full cone nozzles.  

PubMed

The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19 mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55 mm downstream of the nozzle exit. PMID:24307881

Naz, M Y; Sulaiman, S A; Ariwahjoedi, B; Ku Shaari, Ku Zilati

2013-01-01

84

Investigation of Vortex Clouds and Droplet Sizes in Heated Water Spray Patterns Generated by Axisymmetric Full Cone Nozzles  

PubMed Central

The hot water sprays are an important part of many industrial processes, where the detailed knowledge of physical phenomena involved in jet transportation, interaction, secondary breakup, evaporation, and coalescence of droplets is important to reach more efficient processes. The objective of the work was to study the water spray jet breakup dynamics, vortex cloud formation, and droplet size distribution under varying temperature and load pressure. Using a high speed camera, the spray patterns generated by axisymmetric full cone nozzles were visualized as a function water temperature and load pressure. The image analysis confirmed that the spray cone angle and width do not vary significantly with increasing Reynolds and Weber numbers at early injection phases leading to increased macroscopic spray propagation. The formation and decay of semitorus like vortex clouds were also noticed in spray structures generated at near water boiling point temperature. For the nozzle with smallest orifice diameter (1.19?mm), these vortex clouds were very clear at 90°C heating temperature and 1 bar water load pressure. In addition, the sauter mean diameter (SMD) of the spray droplets was also measured by using Phase Doppler Anemometry (PDA) at different locations downstream of the nozzle exit. It was noticed that SMD varies slightly w.r.t. position when measured at room temperature whereas at higher temperature values, it became almost constant at distance of 55?mm downstream of the nozzle exit. PMID:24307881

Naz, M. Y.; Sulaiman, S. A.; Ariwahjoedi, B.; Ku Shaari, Ku Zilati

2013-01-01

85

Cloud top structure of Venus revealed by Subaru/COMICS mid-infrared images  

NASA Astrophysics Data System (ADS)

We have investigated the cloud top structure of Venus by analyzing ground-based images taken at the mid-infrared wavelengths of 8.66 ?m and 11.34 ?m. Venus at a solar phase angle of ?90°, with the morning terminator in view, was observed by the Cooled Mid-Infrared Camera and Spectrometer (COMICS), mounted on the 8.2-m Subaru Telescope, during the period October 25-29, 2007. The disk-averaged brightness temperatures for the observation period are ?230 K and ?238 K at 8.66 ?m and 11.34 ?m, respectively. The obtained images with good signal-to-noise ratio and with high spatial resolution (?200 km at the sub-observer point) provide several important findings. First, we present observational evidence, for the first time, of the possibility that the westward rotation of the polar features (the hot polar spots and the surrounding cold collars) is synchronized between the northern and southern hemispheres. Second, after high-pass filtering, the images reveal that streaks and mottled and patchy patterns are distributed over the entire disk, with typical amplitudes of ?0.5 K, and vary from day to day. The detected features, some of which are similar to those seen in past UV images, result from inhomogeneities of both the temperature and the cloud top altitude. Third, the equatorial center-to-limb variations of brightness temperatures have a systematic day-night asymmetry, except those on October 25, that the dayside brightness temperatures are higher than the nightside brightness temperatures by 0-4 K under the same viewing geometry. Such asymmetry would be caused by the propagation of the migrating semidiurnal tide. Finally, by applying the lapse rates deduced from previous studies, we demonstrate that the equatorial center-to-limb curves in the two spectral channels give access to two parameters: the cloud scale height H and the cloud top altitude zc. The acceptable models for data on October 25 are obtained at H = 2.4-4.3 km and zc = 66-69 km; this supports previous results determined from spacecraft observations.

Sato, T. M.; Sagawa, H.; Kouyama, T.; Mitsuyama, K.; Satoh, T.; Ohtsuki, S.; Ueno, M.; Kasaba, Y.; Nakamura, M.; Imamura, T.

2014-11-01

86

Searching for Pulsars Using Image Pattern Recognition  

NASA Astrophysics Data System (ADS)

In the modern era of big data, many fields of astronomy are generating huge volumes of data, the analysis of which can sometimes be the limiting factor in research. Fortunately, computer scientists have developed powerful data-mining techniques that can be applied to various fields. In this paper, we present a novel artificial intelligence (AI) program that identifies pulsars from recent surveys by using image pattern recognition with deep neural nets—the PICS (Pulsar Image-based Classification System) AI. The AI mimics human experts and distinguishes pulsars from noise and interference by looking for patterns from candidate plots. Different from other pulsar selection programs that search for expected patterns, the PICS AI is taught the salient features of different pulsars from a set of human-labeled candidates through machine learning. The training candidates are collected from the Pulsar Arecibo L-band Feed Array (PALFA) survey. The information from each pulsar candidate is synthesized in four diagnostic plots, which consist of image data with up to thousands of pixels. The AI takes these data from each candidate as its input and uses thousands of such candidates to train its ~9000 neurons. The deep neural networks in this AI system grant it superior ability to recognize various types of pulsars as well as their harmonic signals. The trained AI's performance has been validated with a large set of candidates from a different pulsar survey, the Green Bank North Celestial Cap survey. In this completely independent test, the PICS ranked 264 out of 277 pulsar-related candidates, including all 56 previously known pulsars and 208 of their harmonics, in the top 961 (1%) of 90,008 test candidates, missing only 13 harmonics. The first non-pulsar candidate appears at rank 187, following 45 pulsars and 141 harmonics. In other words, 100% of the pulsars were ranked in the top 1% of all candidates, while 80% were ranked higher than any noise or interference. The performance of this system can be improved over time as more training data are accumulated. This AI system has been integrated into the PALFA survey pipeline and has discovered six new pulsars to date.

Zhu, W. W.; Berndsen, A.; Madsen, E. C.; Tan, M.; Stairs, I. H.; Brazier, A.; Lazarus, P.; Lynch, R.; Scholz, P.; Stovall, K.; Ransom, S. M.; Banaszak, S.; Biwer, C. M.; Cohen, S.; Dartez, L. P.; Flanigan, J.; Lunsford, G.; Martinez, J. G.; Mata, A.; Rohr, M.; Walker, A.; Allen, B.; Bhat, N. D. R.; Bogdanov, S.; Camilo, F.; Chatterjee, S.; Cordes, J. M.; Crawford, F.; Deneva, J. S.; Desvignes, G.; Ferdman, R. D.; Freire, P. C. C.; Hessels, J. W. T.; Jenet, F. A.; Kaplan, D. L.; Kaspi, V. M.; Knispel, B.; Lee, K. J.; van Leeuwen, J.; Lyne, A. G.; McLaughlin, M. A.; Siemens, X.; Spitler, L. G.; Venkataraman, A.

2014-02-01

87

Study of the relations between cloud properties and atmospheric conditions using ground-based digital images  

NASA Astrophysics Data System (ADS)

The aerosol constituents of the earth atmosphere are of great significance for the radiation budget and global climate of the planet. They are the precursors of clouds that in turn play an essential role in these processes and in the hydrological cycle of the Earth. Understanding the complex aerosol-cloud interactions requires a detailed knowledge of the dynamical processes moving the water vapor through the atmosphere, and of the physical mechanisms involved in the formation and growth of cloud particles. Ground-based observations on regional and short time scale provide valuable detailed information about atmospheric dynamics and cloud properties, and are used as a complementary tool to the global satellite observations. The objective of the present paper is to study the physical properties of clouds as displayed in ground-based visible images, and juxtapose them to the specific surface and atmospheric meteorological conditions. The observations are being carried out over the urban area of the city of Sofia, Bulgaria. The data obtained from visible images of clouds enable a quantitative description of texture and morphological features of clouds such as shape, thickness, motion, etc. These characteristics are related to cloud microphysical properties. The changes of relative humidity and the horizontal visibility are considered to be representative of the variations of the type (natural/manmade) and amount of the atmospheric aerosols near the earth surface, and potentially, the cloud drop number concentration. The atmospheric dynamics is accounted for by means of the values of the atmospheric pressure, temperature, wind velocity, etc., observed at the earth's surface. The advantage of ground-based observations of clouds compared to satellite ones is in the high spatial and temporal resolution of the obtained data about the lowermost cloud layer, which in turn is sensitive to the meteorological regimes that determine cloud formation and evolution. It turns out that the visible features of clouds reflect closely the meteorological parameters and their dynamics. There are evidences that time intervals between measurements as short as several minutes may be indicative of the trend of evolution of certain types of clouds. The results show that after taking into consideration the corrections due to the influence of cloud edges on light scattering, the observable changes of cloud properties are in agreement with the follow-up weather. This allows for scrutinizing cloud properties and their relationship with surface and atmospheric properties. The remote sensing of the variations of cloud optical properties by means of visible images taken from earth's surface can help to establish some complex atmospheric interactions and contribute to our knowledge of aerosol and cloud climatology. Acknowledgement: The work is partially supported by the Bulgarian NFSR under contract NZ-1414/04.

Bakalova, Kalinka

88

Local Binary Patterns Calculated Over Gaussian Derivative Images  

E-print Network

Local Binary Patterns Calculated Over Gaussian Derivative Images Varun Jain James L. Crowley analysis. We combine Gaussian derivatives with Local Binary Patterns to provide a robust and powerful derivatives form the input to the Linear Binary Pattern(LBP) operator instead of the original image

Paris-Sud XI, Université de

89

Document image segmentation and quality improvement by moiré pattern analysis  

Microsoft Academic Search

Moiré patterns are distortions on the results of scanning printed documents. However, the patterns can be utilized in document image segmentation and quality improvement. The moiré phenomenon comes from sampling periodical structures in images, such as halftone screens, color components, and text galleys which often appear in printed magazines and newspapers. The generated moiré patterns appear in the scanning result

James Ching-Yu Yang; Wen-Hsiang Tsai

2000-01-01

90

A cloud pattern recognition algorithm to automate the estimation of mass eruption rates from an umbrella cloud or downwind plume observed via satellite imagery  

NASA Astrophysics Data System (ADS)

The eruption of Eyjafjallajökull, Iceland in April and May, 2010, brought to light the importance of Volcanic Ash Transport and Dispersion models (VATD) to the estimation of the position and concentration of ash with time, and how vital it is for Volcanic Ash Advisory Centers (VAACs) to be able to detect and track ash clouds with both observations and models. The VATD needs to get Eruption Source Parameters (ESP), including mass eruption rate through time, as input, which ultimately relies on the detection of the eruption regardless of the meteorological conditions. Volcanic cloud recognition is especially difficult when meteorological clouds are also present, which is typically the case in the tropics. Given the fact that meteorological clouds and volcanic clouds behave differently, we developed an agent-based pattern definition algorithm to detect and define volcanic clouds on satellite imagery. We have combined this with a plume growth rate methodology to automate the estimation of volumetric and mass growth with time using plume geometry provided by satellite imagery. This allows an estimation of the mass eruption rate (MER) with time. To test our approach, we used the examples of two eruptions of different source strength, in two different climatic regimes and for which therefore the weather during eruption was quite different: Grímsvötn (Iceland) May 21, 2011, which produced an umbrella cloud readily seen above the cloud deck, and Manam (Papua New Guinea) October 24, 2004, which produced a stratospheric umbrella cloud that rapidly turned into a downwind plume, and was difficult to distinguish from meteorological clouds. The new methods may in the future allow for fast, easy and automated detection of volcanic clouds as well as a remote assessment of the mass eruption rate with time, even for inaccessible volcanoes. The methods may thus provide an additional path to estimation of the ESP and the forecasting of ash cloud propagation.

Jansons, E.; Pouget, S.; Bursik, M. I.; Patra, A. K.; Pitman, E. B.; Tupper, A.

2013-12-01

91

Clouds  

NSDL National Science Digital Library

Created by Carl Wozniak, Clouds attempts to make the study of clouds and the processes of cloud formation more accessible for elementary and early secondary classroom study. The site accomplishes this by breaking information down into five sections, complemented by both descriptive text and relevant pictures. Pictures and graphics are perhaps the most classroom-friendly section of the site, as they are intended for use in non-profit, educational settings. Another primary section of the site is the glossary, aimed at explaining cloud-related terminology at a very simplistic level, understandable by younger students.

1999-01-01

92

Retrieval of cloud cover parameters from multispectral satellite images  

NASA Technical Reports Server (NTRS)

A technique is described for extracting cloud cover parameters from multispectral satellite radiometric measurements. Utilizing three channels from the AVHRR (Advanced Very High Resolution Radiometer) on NOAA polar orbiting satellites, it is shown that one can retrieve four parameters for each pixel: cloud fraction within the FOV, optical thickness, cloud-top temperature and a microphysical model parameter. The last parameter is an index representing the properties of the cloud particle and is determined primarily by the radiance at 3.7 microns. The other three parameters are extracted from the visible and 11 micron infrared radiances, utilizing the information contained in the two-dimensional scatter plot of the measured radiances. The solution is essentially one in which the distributions of optical thickness and cloud-top temperature are maximally clustered for each region, with cloud fraction for each pixel adjusted to achieve maximal clustering.

Arking, A.; Childs, J. D.

1985-01-01

93

Arecibo imaging of compact high-velocity clouds  

E-print Network

Ten isolated compact high-velocity clouds (CHVCs) of the type cataloged by Braun & Burton (1999) have been imaged with the Arecibo telescope and were found to have a nested core/halo morphology. We argue that a combination of high-resolution filled-aperture and synthesis data is crucial to determining the intrinsic properties of the CHVCs. We identify the halos as Warm Neutral Medium surrounding one or more cores in the Cool Neutral Medium phase. These halos are clearly detected and resolved by the Arecibo filled-aperture imaging, which reaches a limiting sensitivity (1 sigma) of N_H about 2x10^17 cm^-2 over the typical 70 km/s linewidth at zero intensity. The FWHM linewidth of the halo gas is found to be 25 km/s, consistent with a WNM thermal broadening within 10^4 K gas. Substantial asymmetries are found at high N_H (>10^18.5 cm^-2) levels in 60% of our sample. A high degree of reflection-symmetry is found at low N_H (<10^18.5 cm^-2) in all sources studied at these levels. The column-density profiles of the envelopes are described well by the sky-plane projection of a spherical exponential in atomic volume density, which allows estimating the characteristic central halo column density, N_H(0) = 4.1+/-3.2x10^19 cm^-2, and characteristic exponential scale-length, h_B=420+/-90 arcsec. For plausible values of the thermal pressure at the CNM/WNM interface, these edge profiles allow distance estimates to be made for the individual CHVCs studied here which range between 150 and 850 kpc. (abridged)

W. B. Burton; R. Braun; J. N. Chengalur

2001-02-06

94

Introducing spatial information in k-means algorithm for cloud detection in optical satellite images  

Microsoft Academic Search

Due to restricted visibility time of remote sensing polar platforms from earth reception station, on ly a limited number of images can be transmitted. On the case of optical images, an in- board cloud cover detection module will allow to transmit only useful images. In order to derive such a module, we propose a method to detect cloudy areas from

Lauren Beaudoin; Jean-Marie Nicolas; Florence Tupin; M. Hueckel

2001-01-01

95

Structure and Semi-Fluid Motion Analysis of Stereoscopic Satellite Images for Cloud Tracking  

Microsoft Academic Search

Time-varying multispectral observations of cloudsfrom meteorological satellites are used to estimatecloud-top heights (structure) and cloud winds (semifluidmotion). Stereo image pairs over several timesteps were acquired by two geostationary satellites withsynchronized scanning instruments. Cloud-top heightestimation from these image pairs is performed usingan improved automatic stereo analysis algorithm on amassively parallel Maspar computer with 16K processors.A new category of...

Kannappan Palaniappan; Chandra Kambhamettu; Frederick Hasler; Dmitry B. GoldgofS

1995-01-01

96

Advanced infrared sounder subpixel cloud detection with imagers and its impact on radiance assimilation in NWP  

NASA Astrophysics Data System (ADS)

cloud detection is very important for infrared (IR) radiance assimilation; improved cloud detection could reduce cloud contamination and hence improve the assimilation. Although operational numerical weather prediction (NWP) centers are using IR sounder radiance data for cloud detection, collocated high spatial resolution imager data could help sounder subpixel cloud detection and characterization. IR sounder radiances with improved cloud detection using Atmospheric Infrared Sounder (AIRS)/Moderate Resolution Imaging Spectroradiometer (MODIS) were assimilated for Hurricane Sandy (2012). Forecast experiments were run with Weather Research and Forecasting (WRF) as the forecast model and the Three-Dimensional Variational Assimilation (3DVAR)-based Gridpoint Statistical Interpolation (GSI) as the analysis system. Results indicate that forecasts of both hurricane track and intensity are substantially improved when the collocated high spatial resolution MODIS cloud mask is used for AIRS subpixel cloud detection for assimilating radiances. This methodology can be applied to process Crosstrack Infrared Sounder (CRIS)/Visible Infrared Imaging Radiometer Suite (VIIRS) onboard Suomi-NPOESS Preparatory Project (NPP)/Joint Polar Satellite System (JPSS) and Infrared Atmospheric Sounding Interferometer (IASI)/Advanced Very High Resolution Radiometer (AVHRR) onboard the Metop series for improved radiance assimilation in NWP.

Wang, Pei; Li, Jun; Li, Jinlong; Li, Zhenglong; Schmit, Timothy J.; Bai, Wenguang

2014-03-01

97

Interference of Rotating Atomic Clouds  

NASA Astrophysics Data System (ADS)

We study the theory of interference between spinning clouds of ultracold atoms; quantifying how intermeshed vortices in two displaced clouds form intricate patterns when the clouds are overlapped. These patterns, dominated by stripes, can be imaged in circumstances where individual vortices cannot be resolved. We contrast these structures (which were recently observed at JILA [Schweikhard et al. Phys. Rev. Lett. 93, 210403 (2003)]) with the ones which will be seen during the interference of two atomic clouds in highly correlated quantum Hall states. The striking differences in these interference patterns allows one to distinguish coherent and correlated states.

Mueller, Erich; Ho, Tin-Lun

2005-03-01

98

A Method for Compositing Polar MODIS Satellite Images to Remove Cloud Cover for Landfast Sea-Ice Detection  

Microsoft Academic Search

This paper presents details of techniques for generating thermal infrared and visible composite images from the cloud-free portions of temporally closely spaced MODerate resolution Imaging Spectroradiometer (MODIS) images, with a focus on studies of landfast sea ice along the East Antarctic coast. Composite image inclusion criteria are based on modified MODIS Earth Observing System cloud mask product results. The compositing

Alexander D. Fraser; Robert A. Massom; Kelvin J. Michael

2009-01-01

99

Analysis of dust cloud combustion using FAST Infrared Imaging  

NASA Astrophysics Data System (ADS)

Dust cloud combustion is unfortunately at risk in many working environments, jeopardizing several workers. The heat and shock waves resulting from the flame propagation into the dust cloud are harmful and lead to major endangerment or casualties. More precisely, dust cloud (small particles) explosions are even more malicious since they often result from ordinary materials such as coal, flour or pollen. Also, many metal powdered (such as aluminum oxide and magnesium) can form dangerous dust cloud when they are in suspensions in air. The understanding of this particular type of combustion is critical for the preventive care of sites and workers afflicted to such conditions. This paper presents the results of a dynamic flow analysis of metal particles combustion in a dust cloud. The ignition points, the flow rate as well as the propagation direction of the flow have been characterized using fast infrared imagery.

Marcotte, Frederick; Farley, Vincent; Savary, Simon

2013-05-01

100

Patterns and connections between aerosols, clouds and vegetation in the Amazon as seen by the twin MODIS sensors aboard Terra and Aqua  

NASA Astrophysics Data System (ADS)

In this study, twin Moderate Resolution Imaging Spectroradiometer (MODIS) sensors aboard NASA's Terra and Aqua satellites are used for characterization of cloud development and identification of processes affecting cloud formation. We find that much of the development of microphysical properties of water clouds over the Brazilian Legal Amazon can be characterized by the simple difference between those properties observed at the two times of MODIS overpass, only 3 hours apart. The time window is small enough that observed differences in cloud properties are primarily associated with the local events; therefore, it is ideal for exploring the effects of plant transpiration, biomass burning and Secondary Organic Aerosol (SOA) formation on regional cloud properties. In this region we find that the effective cloud droplet radius observed in the afternoon by Aqua-MODIS is systematically higher than the effective radii observed in the morning by Terra-MODIS. The difference corresponds to the invigoration of convection in the afternoon with the corresponding growth of droplet size. The monthly mean difference is 1 to 2 um, depending on season, but the overall pattern of the difference prevails throughout the Amazon, is repeated over other tropical rain forest regions globally, and is strikingly different from other types of cloud systems around the globe. Furthermore, we find that the effective radius difference found in the Amazon is inversely correlated to measures of evapotranspiration and all-sky solar radiation at the surface, but is not well-correlated to precipitation. The picture that emerges is a complex one that intertwines a light- limited forest, aerosols (both biogenic and anthropogenic) and cloud development.

Meskhidze, N.; Negrón Juárez, R.; Remer, L.; Platnick, S.; Aiyyer, A.

2007-12-01

101

Thirty Years of Cloud Cover Patterns from Satellite Data: Fog in California's Central Valley and Coast  

NASA Astrophysics Data System (ADS)

In an effort to assess long term trends in winter fog in the Central Valley of California, custom maps of daily cloud cover from an approximately 30 year record of AVHRR (1981-1999) and MODIS (2000-2012) satellite data were generated. Spatial rules were then used to differentiate between fog and general cloud cover. Differences among the sensors (e.g., spectral content, spatial resolution, overpass time) presented problems of consistency, but concurrent climate station data were used to resolve systematic differences in products, and to confirm long term trends. The frequency and extent of Central Valley ("Tule") fog appear to have some periodic oscillation, but also appear to be on the decline, especially in the Sacramento Valley and in the "shoulder" months of November and February. These results may have strong implications for growers of fruit and nut trees in the Central Valley dependent on winter chill hours that are augmented by the foggy daytime conditions. Conclusions about long term trends in fog are limited to daytime patterns, as results are primarily derived from reflectance-based products. Similar analyses of daytime cloud cover are performed on other areas of concern, such as the coastal fog belt of California. Large area and long term patterns here appear to have periodic oscillation similar to that for the Central Valley. However, the relatively coarse spatial resolution of the AVHRR LTDR (Long Term Data Record) data (~5-km) may be limiting for fine-scale analysis of trends.

Waller, E.; Baldocchi, D. D.

2012-12-01

102

Space radar image of Western Pacific rain clouds  

NASA Technical Reports Server (NTRS)

This radar image shows the ocean surface in a portion of the Western Pacific Ocean. Scientists are using images like this to study the occurrence, distribution and activity of tropical rain squalls and to understand the exchange of heat between the atmosphere and ocean and the upper layer mixing in the tropical oceans, which are critical factors for understanding the driving forces which produce the El Nino phenomenon. The white, curved area at the top of the image is a portion of the Ontong Java Atoll, part of the Solomon Islands group. The yellowish green area near the bottom of the image is an intense rain cell. This image is centered near 5.5 degrees South latitude and 159.5 degrees East longitude. The area shown is 50 kilometers by 21 kilometers (31 miles by 13 miles). This image was acquired by the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) aboard the space shuttle Endeavour on its 13th orbit on April 10, 1994. The colors in the image are assigned to different frequencies and polarizations of the SIR-C radar as follows: Red is C-band horizontally transmitted and received; green is L-band horizontally transmitted and vertically received and blue is L-band horizontally transmitted and received. The large rain cell is about 15 kilometers by 15 kilometers (9 miles by 9 miles) and contains two dark regions, one circular and one rectangular, inside it. Two smaller reddish cells are visible closer to the atoll. The red areas may be caused by reflection from ice particles in the colder, upper portion of the storm cell and not from the ocean surface at all. This provides direct evidence that it is raining within this storm cell, valuable information which is usually very difficult to measure over more remote regions of the ocean away from coastal-based weather systems. The dark holes in the middle of the cell are thought to be areas of very heavy rainfall which actually smooth out the ocean surface and result in lower radar returns. The surrounding ocean is blue to green plus black. Winds and currents cause the ocean surface to be rough and those variations on the surface affect how the radar signals bounce off the surface. The bright areas on the image correspond to areas where the wind speed is high. The highest winds are seen as the yellow-green region of the large rain cell. The lowest winds are seen inside the atoll as dark areas. Outside the rain cell, the winds are moderately low, which is indicated by the puff-like, blue patterns surrounding the cell and extending into the atoll. The long, thin, dark lines extending across the ocean are surface currents. Here the currents are likely accumulating natural oils caused by small marine biological organisms. The oils cause the small, wind-generated waves to be reduced in size or damped which produces a smooth, dark zone on the radar image.

1995-01-01

103

Cloud Remote Sensing with Sideways-Looks : Theory and First Results Using Multispectral Thermal Imager Data  

SciTech Connect

In operational remote sensing, the implicit model for cloud geometry is a homogeneous plane-parallel slab of infinite horizontal extent. Each pixel is indeed processed as if it exchanged no radiant energy whatsoever with its neighbors. The shortcomings of this conceptual model have been well documented in the specialized literature but rarely mitigated. The worst-case scenario is probably high-resolution imagery where dense isolated clouds are visible, often both bright (reflective) and dark (transmissive) sides being apparent from the same satellite viewing angle: the low transmitted radiance could conceivably be interpreted in plane-parallel theory as no cloud at all. An alternative to the plane-parallel cloud model is introduced here that has the same appeal of being analytically tractable, at least in the diffusion limit: the spherical cloud. This new geometrical paradigm is applied to radiances from cumulus clouds captured by DOE's Multispectral Thermal Imager (MTI). Estimates of isolated cloud opacities are a necessary first step in correcting radiances from surface targets that are visible in the midst of a broken-cloud field. This type of advanced atmospheric correction is badly needed in remote sensing applications such as nonproliferation detection were waiting for a cloud-free look in the indefinite future is not a viable option.

Davis, A. B. (Anthony B.)

2002-01-01

104

Thermal ghost imaging with averaged speckle patterns  

E-print Network

We present theoretical and experimental results showing that a thermal ghost imaging system can produce images of high quality even when it uses detectors so slow that they respond only to intensity-averaged (that is, ...

Shapiro, Jeffrey H.

105

Time evolution of surface chlorophyll patterns from cross-spectrum analysis of satellite color images  

NASA Technical Reports Server (NTRS)

The rate of decorrelation of surface chlorophyll patterns as a function of the time separation between pairs of images was determined from two sequences of CZCS images of the Pacific Ocean area adjacent to Vancouver Island, Canada; cloud-free subareas were selected that were common to several images separated in time by 1-17 days. Image pairs were subjected to two-dimensional autospectrum and cross-spectrum analysis in an array processor, and squared coherence estimates found for several wave bands were plotted against time separation, in analogy with a time-lagged cross correlation function. It was found that, for wavelengths of 50-150 km, significant coherence was lost after 7-10 days, while for wavelengths of 25-50 km, significant coherence was lost after only 5-7 days. In both cases, offshore regions maintained coherence longer than coastal regions.

Denman, Kenneth L.; Abbott, Mark R.

1988-01-01

106

Image processing methods in two and three dimensions used to animate remotely sensed data. [cloud cover  

NASA Technical Reports Server (NTRS)

Image processing methods and software used to animate nonimaging remotely sensed data on cloud cover are described. Three FORTRAN programs were written in the VICAR2/TAE image processing domain to perform 3D perspective rendering, to interactively select parameters controlling the projection, and to interpolate parameter sets for animation images between key frames. Operation of the 3D programs and transferring the images to film is automated using executive control language and custom hardware to link the computer and camera.

Hussey, K. J.; Hall, J. R.; Mortensen, R. A.

1986-01-01

107

Visual pattern based colour image compression G. Schaefer+  

E-print Network

& Imaging Institute ++ School of Computing & Mathematics University of Derby, UK ABSTRACT A novel colour of predefined, universal visual patterns in a uniform colour space. Source coding and colour quantisation per pixel) needed to represent a digital image whilst trying to maintain high perceptual image quality

Aickelin, Uwe

108

Infrared cloud imaging in support of Earth-space optical communication.  

PubMed

The increasing need for high data return from near-Earth and deep-space missions is driving a demand for the establishment of Earth-space optical communication links. These links will require a nearly obstruction-free path to the communication platform, so there is a need to measure spatial and temporal statistics of clouds at potential ground-station sites. A technique is described that uses a ground-based thermal infrared imager to provide continuous day-night cloud detection and classification according to the cloud optical depth and potential communication channel attenuation. The benefit of retrieving cloud optical depth and corresponding attenuation is illustrated through measurements that identify cloudy times when optical communication may still be possible through thin clouds. PMID:19434118

Nugent, Paul W; Shaw, Joseph A; Piazzolla, Sabino

2009-05-11

109

Variations of zonal wind speed at Venus cloud tops from Venus Monitoring Camera UV images  

NASA Astrophysics Data System (ADS)

7 years of continuous monitoring of Venus by ESA's Venus Express provided an opportunity to study dynamics of the atmosphere of Venus. Venus Monitoring Camera (VMC) [1] delivered the longest and the most complete so far set of UV images to study the cloud level circulation by tracking motion of the cloud features. We analyzed 130 orbits with manual cloud tracking and 600 orbits with digital correlation method. Here we present the latest update of our results. Total number of wind vectors derived in this work is approximately a half million. During Venus Express observations the mean zonal speed was in the range of 85-110 m/s. VMC observations indicated a long term trend for the zonal wind speed at low latitudes to increase. The origin of low frequency trend with a period about 3000 days is unclear. Fourier analysis [2-3] of revealed quasi-periodicities in the zonal circulation at low latitudes. Two groups of the periods were found. The first group is close to the period of superrotation at low latitudes (4.83±0.1 days) with the period 4.1-5.1 days and the amplitude ranging from ±4.2 to ±17.4 m/s. The amplitude and phase of oscillations demonstrates dependence from the latitude and also time variability with preserving stable parameters of oscillation during at least 70 days. Short term oscillations may be caused by wave processes in the mesosphere of Venus at the cloud top level. Wave number of the observed oscillations is 1. The second group is a long term periods caused by orbital motion of Venus (116 days, 224 days) and is related to the periodicity in VMC observations. Also VMC UV observations showed a clear diurnal pattern of the mean circulation. The zonal wind demonstrated semi-diurnal variations with minimum speed close to noon (11-14 h) and maxima in the morning (8-9 h) and in the evening (16-17 h). The meridional component clearly peaks in the early afternoon (13-15h) at latitudes near 50S. The minimum of the meridional wind is located at low latitudes in the morning (8-11h). References [1] Markiewicz W. J. et al.: Venus Monitoring Camera for Venus Express // Planet. Space Sci.. V.55(12). pp1701-1711. doi:10.1016/j.pss.2007.01.004, 2007. [2] Deeming T.J.: Fourier analysis with unequally-spaced data. Astroph. and Sp. Sci. V.36, pp137-158, 1975. [3] Terebizh, V.Yu. Time series analysis in astrophysics. Moscow: "Nauka," Glav. red. fiziko-matematicheskoi lit-ry, 1992. In Russian

Khatuntsev, Igor; Patsaeva, Marina; Ignatiev, Nikolai; Titov, Dmitri; Markiewicz, Wojciech J.

2013-04-01

110

Development of a GOES-R Advanced Baseline Imager Solar Channel Radiance Simulator for Ice Clouds  

E-print Network

Development of a GOES-R Advanced Baseline Imager Solar Channel Radiance Simulator for Ice Clouds Satellite R (GOES-R) Advanced Baseline Imager (ABI) solar channels. The simulator is based on the discrete single-scattering property database of both smooth and severely roughened ice particles, which include

Baum, Bryan A.

111

Infrared Imaging of the Large Magellanic Cloud Star-forming Region Henize 206  

Microsoft Academic Search

Henize 206 is a region of star formation in the Large Magellanic Cloud of the approximate scale of the Orion belt and sword. Our Spitzer Space Telescope infrared images and Cerro Tololo Inter-American Observatory (CTIO) optical images show that the region is experiencing very energetic star formation. The radiation from young stars has excited strong polycyclic aromatic hydrocarbon (PAH) emission

V. Gorjian; M. W. Werner; J. R. Mould; K. D. Gordon; J. Muzzerole; J. Morrison; J. M. Surace; L. M. Rebull; R. L. Hurt; R. C. Smith; C. Aguilera; J. M. De Buizer; C. Packham

2004-01-01

112

Single-shot three-dimensional imaging of dilute atomic clouds  

NASA Astrophysics Data System (ADS)

Light field microscopy methods together with three dimensional (3D) deconvolution can be used to obtain single shot 3D images of atomic clouds. We demonstrate the method using a test setup which extracts three dimensional images from a fluorescent $^{87}$Rb atomic vapor.

Sakmann, Kaspar; Kasevich, Mark

2014-09-01

113

Cassini imaging of Titan's high-latitude lakes, clouds, and south-polar surface changes  

E-print Network

Cassini imaging of Titan's high-latitude lakes, clouds, and south-polar surface changes E. P 2009. [1] Cassini's Imaging Science Subsystem (ISS) has been observing Titan since April 2004, suggesting the presence of hydrocarbon lakes similar to those later detected at Titan's North Pole

114

High-resolution imaging of compact high-velocity clouds  

E-print Network

Six examples of the compact, isolated high-velocity HI clouds (CHVCs) identified by Braun and Burton (1999) have been imaged with the WSRT. The 65 confirmed objects in this class define a dynamically cold system, with a global minimum for the velocity dispersion of only 70 km/s, found in the Local Group Standard of Rest, while in-falling at 100 km/s toward the LG barycenter. These objects have a characteristic morphology, in which several compact cores are embedded in a diffuse halo. The compact cores typically account for 40% of the HI line flux while covering some 15% of the source area. The cores are the cool condensed phase of HI, the CNM, with temp. near 100 K, while the halos appear to be a shielding column of warm diffuse HI, the WNM, with temp. near 8000 K. We detect a core with one of the narrowest HI emission lines ever observed, with intrinsic FWHM of 2 km/s and 75 K brightness. From a comparison of column and volume densities we derive a distance in the range 0.5 to 1 Mpc. We determine a metallicity for this same object of 0.04 to 0.07 solar. Comparably high distances are implied by demanding the stability of objects with multiple cores, which show relative velocities as large as 70 km/s on 30 arcmin scales. Many compact cores show systematic velocity gradients along the major axis of their elliptical extent which are consistent with circular rotation. Several of the derived rotation curves are well-fit by Navarro, Frenk, and White (1997) cold dark matter profiles. These kinematic signatures imply a high dark-to-visible mass ratio of 10-50, for D=0.7Mpc, which scales as 1/D. The implied dark matter halos dominate the mass volume density within the central 2 kpc (10 arcmin) of each source, providing a sufficent hydrostatic pressure to allow local CNM condensation. (abridged)

Robert Braun; Butler Burton

1999-12-20

115

The radiative consistency of Atmospheric Infrared Sounder and Moderate Resolution Imaging Spectroradiometer cloud retrievals  

Microsoft Academic Search

The consistency of cloud top temperature (TC) and effective cloud fraction (f) retrieved by the Atmospheric Infrared Sounder (AIRS)\\/Advanced Microwave Sounding Unit (AMSU) observation suite and the Moderate Resolution Imaging Spectroradiometer (MODIS) on the EOS-Aqua platform are investigated. Collocated AIRS and MODIS TC and f are compared via an “effective scene brightness temperature” (Tb,e). Tb,e is calculated with partial field

Brian H. Kahn; Evan Fishbein; Shaima L. Nasiri; Annmarie Eldering; Eric J. Fetzer; Michael J. Garay; Sung-Yung Lee

2007-01-01

116

Wide-angle imaging lidar (WAIL): a ground-based instrument for monitoring the thickness and density of optically thick clouds  

NASA Astrophysics Data System (ADS)

Traditional lidar provides little information on dense clouds beyond the range to their base (ceilometry), due to their extreme opacity. At most optical wavelengths, however, laser photons are not absorbed but merely scattered out of the beam, and thus eventually escape the cloud via multiple scattering, producing distinctive extended space- and time-dependent patterns which are, in essence, the cloud's radiative Green functions. These Green functions, essentially 'movies' of the time evolution of the spatial distribution of escaping light, are the primary data products of a new type of lidar: Wide Angle Imaging Lidar (WAIL). WAIL data can be used to infer both optical depth and physical thickness of clouds, and hence the cloud liquid water content. The instrumental challenge is to accommodate a radiance field varying over many orders of magnitude and changing over widely varying time-scales. Our implementation uses a high-speed microchannel plate/crossed delay line imaging detector system with a 60-degree full-angle field of view, and a 532 nm doubled Nd:YAG laser. Nighttime field experiments testing various solutions to this problem show excellent agreement with diffusion theory, and retrievals yield plausible values for the optical and geometrical parameters of the observed cloud decks.

Love, Steven P.; Davis, Anthony B.; Rohde, Charles A.; Ho, Cheng

2001-09-01

117

Titan's Clouds from Gemini and Keck Adaptive Optics Imaging  

NASA Astrophysics Data System (ADS)

Using adaptive optics on the Gemini and Keck II telescopes, we found a thin haze and discrete clouds in Titan's south polar troposphere. The discrete clouds vary on timescales of a few hours. We propose a seasonal mechanism to explain the formation of this spring polar tropospheric haze. Assuming that the clouds are located in or above the haze, we suggest that convection within this haze layer triggers methane condensation; subsequent latent heat release leads to vigorous convection and formation of transient clouds. Our results have significant implications for planning the Cassini mission flybys of Titan. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation (NSF) on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina). This paper is based on observations obtained with the Adaptive Optics System Hokupa`a/QUIRC, developed and operated by the University of Hawaii Adaptive Optics Group, with support from the NSF.

Roe, H. G.; de Pater, I.; Macintosh, B. A.; McKay, C. P.

2002-12-01

118

Secure Medical Images Sharing over Cloud Computing environment  

Microsoft Academic Search

Nowadays, many applications have been appeared due to the rapid development in the term of telecommunication. One of these applications is the telemedicine where the patients39; digital data can transfer between the doctors for farther diagnosis. Therefore, the protection of the exchanged medical data is essential especially when transferring these data in an insecure medium such as the cloud computing

2013-01-01

119

Automatic registration of Iphone images to LASER point clouds of the urban structures using shape features  

NASA Astrophysics Data System (ADS)

Fusion of 3D airborne laser (LIDAR) data and terrestrial optical imagery can be applied in 3D urban modeling and model up-dating. The most challenging aspect of the fusion procedure is registering the terrestrial optical images on the LIDAR point clouds. In this article, we propose an approach for registering these two different data from different sensor sources. As we use iPhone camera images which are taken in front of the interested urban structure by the application user and the high resolution LIDAR point clouds of the acquired by an airborne laser sensor. After finding the photo capturing position and orientation from the iPhone photograph metafile, we automatically select the area of interest in the point cloud and transform it into a range image which has only grayscale intensity levels according to the distance from the image acquisition position. We benefit from local features for registering the iPhone image to the generated range image. In this article, we have applied the registration process based on local feature extraction and graph matching. Finally, the registration result is used for facade texture mapping on the 3D building surface mesh which is generated from the LIDAR point cloud. Our experimental results indicate possible usage of the proposed algorithm framework for 3D urban map updating and enhancing purposes.

Sirmacek, B.; Lindenbergh, R. C.; Menenti, M.

2013-10-01

120

On the camparability of cloud fractions derived from whole sky imager and ceilometer data  

SciTech Connect

The Atmospheric Radiation Measurement (ARM) Program`s most heavily instrumented site is its central facility in Lamont, OK. With respect to cloud observations, the instrumentation included a whole sky imager, ceilometers, lidar, millimeter cloud radar, microwave profilers, and radiosondes. Data from three of these instrument--the Whole Sky Imager (WSI), Belfort Laser Ceilometer (BLC) and Micropulse Lidar (MPL)-- are used in this study primarily to investigate the utility of using ceilometers, now strategically emplaced at four additional locations along the perimeter of the site.

Rodriguez, D.

1998-01-30

121

Body Image Perceptions and Eating Patterns Among Preadolescent Children  

Microsoft Academic Search

Preadolescent children are showing patterns of body distortion and unhealthy dieting practices to attempt weight manipulation. The present study examined body image perceptions and interest in weight manipulation among 215 preadolescent children (girls, n =101) (mean age = 10) in third, fourth, and fifth grades. To measure body image perceptions, children were asked to answer two multiple choice questions: I

Karen M. Skemp-Arlt; Richard P. Mikat

2007-01-01

122

Suppression of fixed pattern noise for infrared image system  

Microsoft Academic Search

In this paper, we propose suppression of fixed pattern noise (FPN) and compensation of soft defect for improvement of object tracking in cooled staring infrared focal plane array (IRFPA) imaging system. FPN appears an observable image which applies to non-uniformity compensation (NUC) by temperature. Soft defect appears glittering black and white point by characteristics of non-uniformity for IR detector by

Jungsoo Han; Kyung-Hoon Bae

2008-01-01

123

Coordinated 1996 HST and IRTF Imaging of Neptune and Triton. III. Neptune's Atmospheric Circulation and Cloud Structure  

NASA Astrophysics Data System (ADS)

The first coordinated multispectral imaging of Neptune and Triton, using both the Hubble Space Telescope and the NASA Infrared Telescope Facility in August 1996 (L. A. Sromovsky et al., 149, 416-434, 435-458), provides new insights into Neptune's atmospheric circulation and cloud structure. From our 1996 data we derived cloud-tracked winds for 18 features spanning latitudes from 61°S to 38°N, finding generally close agreement with the smoothed 1989 Voyager wind profile (Sromovsky et al. 1993, Icarus105, 110-141), except for features associated with a northern Great Dark Spot (GDS), which moved with the spot rather than with the local mass flow, providing another example of GDS traveling companions. In addition to finding a GDS at ˜32°N, thought to be the same one first seen in 1994 near the same latitude (Hammel et al. 1995, Science268, 1740-1742), we also found a new kind of GDS at ˜15°N, which is unusual because of its low latitude and lack of a bright companion. From blue images we determined that the dark cloud band near 60°S latitude is significantly nonaxisymmetric, as was a similar band in 1989 Voyager images, both with a wavenumber-one zonal structure and a ˜5° latitudinal variation. We also identified a persistent pattern of clouds at 45°S, which exhibit strong variations in brightness on yearly time scales. Using HST archived observations, we determined cloud-tracked winds for June and November 1994 and September 1995, confirming and extending the 1995 result of Hammel and Lockwood (1997, Icarus129, 466-481) that most winds agreed with the Voyager profile. A significant exception we found in November 1994 is the ˜100 m/s meridional motion within the transient structure identified as the "bright complex" by H. B. Hammel and G. W. Lockwood (1997, Icarus129, 466-481). The integrated brightness of this group of GDS traveling companions is sufficient to produce a hemispheric brightness asymmetry of 0.36 mag (Sromovsky et al., 149, 435-458), comparable to the 0.44 mag associated with the 1987 "outburst" maximum (Hammel et al. 1992, Icarus99, 363-367). We determined spectral differences in cloud bands using complete global mosaics of 1996 imagery. Colocation of features in HST and groundbased near-IR images enabled us to characterize spectral variations in discrete features from the visible to 2.4 ?m, from which we estimated cloud heights for discrete bright features ranging from 60 to 230 mbars. We found the equatorial atmosphere that is free of bright clouds to be very dark beyond 0.7 ?m, from which we derived new upper bounds of ˜0.2 and ˜0.1 at 1.27 and 1.6 ?m, respectively, on the single-scattering albedo of the putative 3.8-bar H 2S cloud.

Sromovsky, L. A.; Fry, P. M.; Dowling, T. E.; Baines, K. H.; Limaye, S. S.

2001-02-01

124

Image synthesis from nonimaged laser-speckle patterns  

Microsoft Academic Search

We demonstrate that unspeckled images of coherently illuminated, diffuse objects can be formed from measure- ments of backscattered laser-speckle intensity. The theoretical basis for this imaging technique is outlined, and results of computer experiments that successfully construct images from digitally simulated laser-speckle measure- ments are presented. It is well known that the spatial structure of a fully developed laser-speckle pattern-produced

Paul S. Idell; J. R. Fienup; Ron S. Goodman

1987-01-01

125

An automatic self-learning cloud-filtering algorithm for Meteosat Second Generation–Spinning Enhanced Visible and Infrared Imager  

Microsoft Academic Search

Cloud detection is an important pre-processing step to derive operational products from meteorological satellites. This work presents a new cloud-detection algorithm with Meteosat Second Generation (MSG) images, operative at global scale. The algorithm takes advantage of the spectral and temporal resolution of the Spinning Enhanced Visible and Infrared Imager (SEVIRI) sensor. The algorithm is fully automatic in all its stages,

Pablo Salvador; Abel Calle; Julia Sanz; Javier Rodríguez; Jose-Luis Casanova

2013-01-01

126

Automated estimation of mass eruption rate of volcanic eruption on satellite imagery using a cloud pattern recognition algorithm  

NASA Astrophysics Data System (ADS)

The need to detect and track the position of ash in the atmosphere has been highlighted in the past few years following the eruption Eyjafjallajokull. As a result, Volcanic Ash Advisory Centers (VAACs) are using Volcanic Ash Transport and Dispersion models (VATD) to estimate and predict the whereabouts of the ash in the atmosphere. However, these models require inputs of eruption source parameters, such as the mass eruption rate (MER), and wind fields, which are vital to properly model the ash movements. These inputs might change with time as the eruption enters different phases. This implies tracking the ash movement as conditions change, and new satellite imagery comes in. Thus, ultimately, the eruption must be detectable, regardless of changing eruption source and meteorological conditions. Volcanic cloud recognition can be particularly challenging, especially when meteorological clouds are present, which is typically the case in the tropics. Given the fact that a large fraction of the eruptions in the world happen in a tropical environment, we have based an automated volcanic cloud recognition algorithm on the fact that meteorological clouds and volcanic clouds behave differently. As a result, the pattern definition algorithm detects and defines volcanic clouds as different object types from meteorological clouds on satellite imagery. Following detection and definition, the algorithm then estimates the area covered by the ash. The area is then analyzed with respect to a plume growth rate methodology to get estimation of the volumetric and mass growth with time. This way, we were able to get an estimation of the MER with time, as plume growth is dependent on MER. To test our approach, we used the examples of two eruptions of different source strength, in two different climatic regimes, and for which therefore the weather during the eruption was quite different: Manam (Papua New Guinea) January 27 2005, which produced a stratospheric umbrella cloud and was difficult to distinguish from meteorological clouds, and Okmok (Alaska) July 12 2008, which was also an umbrella cloud, but started as an ash-rich cloud before getting a vapor rich pulse into the cloud. The new methods may in the future allow for fast, easy and automated detection of volcanic clouds as well as remote assessment of the MER with time, even for inaccessible volcanoes. The methods may thus provide an additional path to estimation of the ESP and the forecasting of ash cloud propagation with time as the eruption changes.

Pouget, Solene; Jansons, Emile; Bursik, Marcus; Tupper, Andrew; Patra, Abani; Pitman, Bruce; Carn, Simon

2014-05-01

127

Characterizing spatial and temporal patterns of cloud cover and fog inundation for the Northern Channel islands of California  

NASA Astrophysics Data System (ADS)

The presence of low-lying stratocumulus clouds and fog has been known to modify biophysical and ecological properties in a variety of ecosystems in different climates. This is especially true for California's Channel Islands, where forests are frequently shaded by low-lying clouds or immersed in fog during warm and dry summer months. Previous studies suggest that clouds strongly modulate forest distributions as well as carbon and water budgets in these semi-arid environments by reducing solar insolation and raising relative humidity and thus reducing evapotranspiration, while also potentially supplying water directly to the landscape from fog-drip. While summertime fog and stratus cover in California's Channel Islands can ameliorate summer drought stress and enhance soil water budgets, they often have different spatial and temporal patterns. These differing patterns and the resulting shifts in relative ecological importance of fog and stratus are understudied. The overall objective of this study is to map spatial and temporal distributions of daytime cloud cover frequency for the California Channel Islands, and to predict probabilities of surface cloud (fog) contact and immersion for these islands. The results of this research are significant for water balance modeling, help explain vegetation patterns on the islands, and better identify locations where native vegetation restoration efforts are likely to be most successful.

Rastogi, Bharat

128

Physics principles in radiometric infrared imaging of clouds in the atmosphere  

NASA Astrophysics Data System (ADS)

Imaging the atmosphere with a thermal infrared camera can yield a rich variety of information, ranging from the water-vapour content to the spatial distribution of clouds. Such remote sensing measurements are being used to study climate and to characterize ground-station sites for Earth-space optical communications. The key to turning interesting but qualitative images into the highly accurate quantitative images required for this type of research is careful radiometric calibration. This is especially true when using uncooled microbolometer cameras, which are becoming widely available at relatively low cost. When such cameras are calibrated properly, their images illustrate a variety of important basic principles of optics and atmospheric physics related to thermal emission and absorption by atmospheric gases and clouds.

Shaw, Joseph A.; Nugent, Paul W.

2013-11-01

129

Machine learning patterns for neuroimaging-genetic studies in the cloud  

PubMed Central

Brain imaging is a natural intermediate phenotype to understand the link between genetic information and behavior or brain pathologies risk factors. Massive efforts have been made in the last few years to acquire high-dimensional neuroimaging and genetic data on large cohorts of subjects. The statistical analysis of such data is carried out with increasingly sophisticated techniques and represents a great computational challenge. Fortunately, increasing computational power in distributed architectures can be harnessed, if new neuroinformatics infrastructures are designed and training to use these new tools is provided. Combining a MapReduce framework (TomusBLOB) with machine learning algorithms (Scikit-learn library), we design a scalable analysis tool that can deal with non-parametric statistics on high-dimensional data. End-users describe the statistical procedure to perform and can then test the model on their own computers before running the very same code in the cloud at a larger scale. We illustrate the potential of our approach on real data with an experiment showing how the functional signal in subcortical brain regions can be significantly fit with genome-wide genotypes. This experiment demonstrates the scalability and the reliability of our framework in the cloud with a 2 weeks deployment on hundreds of virtual machines. PMID:24782753

Da Mota, Benoit; Tudoran, Radu; Costan, Alexandru; Varoquaux, Gael; Brasche, Goetz; Conrod, Patricia; Lemaitre, Herve; Paus, Tomas; Rietschel, Marcella; Frouin, Vincent; Poline, Jean-Baptiste; Antoniu, Gabriel; Thirion, Bertrand

2014-01-01

130

APHELION WATER-ICE CLOUD MAPPING AND PROPERTY RETRIEVAL USING THE OMEGA/MEX IMAGING SPECTROMETER.  

E-print Network

APHELION WATER-ICE CLOUD MAPPING AND PROPERTY RETRIEVAL USING THE OMEGA/MEX IMAGING SPECTROMETER. J. Wolff, Space Science Institute, Boulder, Colorado, USA, F. Montmessin, LATMOS, CNRS'Astrophysique Spatiale, Orsay, France, B. Schmitt, Laboratoire de Plan´etologie de Grenoble, UJF/CNRS, France. Mapping

Madeleine, Jean-Baptiste

131

GROUND-BASED CLOUD IMAGES AND SKY RADIANCES IN THE VISIBLE AND NEAR INFRARED REGION FROM  

E-print Network

GROUND-BASED CLOUD IMAGES AND SKY RADIANCES IN THE VISIBLE AND NEAR INFRARED REGION FROM WHOLE SKY and near infrared # uwe.feister@dwd.de #12;region was developed at UCSD upon requests of the German Weather reliably with one interruption to correct align- ment of the filter wheels. Some general features

Shields, Janet

132

Infrared cloud imaging in support of Earth-space optical communication  

E-print Network

. Soc. 83, 1771­1790 (2002). 10. G. P. Anderson, A. Berk, P. K. Acharya, M. W. Matthew, L. S. Bernstein for remote sensing," Proc. SPIE 3866, 2­10 (1999). 11. G. P. Anderson, S. A. Clough, F. X. Kneizys, J. HInfrared cloud imaging in support of Earth- space optical communication Paul W. Nugent,1 Joseph A

Shaw, Joseph A.

133

Robust Message-Privacy Preserving Image Copy Detection for Cloud-based Systems  

E-print Network

Robust Message-Privacy Preserving Image Copy Detection for Cloud-based Systems M. Diephuis, S--In this paper we propose an architecture for message-privacy preserving copy detection and content identi. The architecture allows for search- ing in encrypted data and places the computational burden on the server. Sign

Genève, Université de

134

Fluorescence Imaging for Visualization of the Ion Cloud in a Quadrupole Ion Trap Mass Spectrometer  

NASA Astrophysics Data System (ADS)

Laser-induced fluorescence is used to visualize populations of gaseous ions stored in a quadrupole ion trap (QIT) mass spectrometer. Presented images include the first fluorescence image of molecular ions collected under conditions typically used in mass spectrometry experiments. Under these "normal" mass spectrometry conditions, the radial ( r) and axial ( z) full-width at half maxima (FWHM) of the detected ion cloud are 615 and 214 ?m, respectively, corresponding to ~6 % of r 0 and ~3 % of z 0 for the QIT used. The effects on the shape and size of the ion cloud caused by varying the pressure of helium bath gas, the number of trapped ions, and the Mathieu parameter q z are visualized and discussed. When a "tickle voltage" is applied to the exit end-cap electrode, as is done in collisionally activated dissociation, a significant elongation in the axial, but not the radial, dimension of the ion cloud is apparent. Finally, using spectroscopically distinguishable fluorophores of two different m/ z values, images are presented that illustrate stratification of the ion cloud; ions of lower m/ z (higher q z ) are located in the center of the trapping region, effectively excluding higher m/ z (lower q z ) ions, which form a surrounding layer. Fluorescence images such as those presented here provide a useful reference for better understanding the collective behavior of ions in radio frequency (rf) trapping devices and how phenomena such as collisions and space-charge affect ion distribution.

Talbot, Francis O.; Sciuto, Stephen V.; Jockusch, Rebecca A.

2013-12-01

135

New 20-cm radio-continuum study of the small Magellanic cloud: Part I - Images  

E-print Network

We present and discuss new high-sensitivity and resolution radio-continuum images of the Small Magellanic Cloud (SMC) at lambda=20 cm (nu=1.4 GHz). The new images were created by merging 20-cm radiocontinuum archival data, from the Australian Telescope Compact Array and the Parkes radio-telescope. Our images span from ~10'' to ~150'' in resolution and sensitivity of r.m.s.>=0.5 mJy/beam. These images will be used in future studies of the SMC's intrinsic sources and its overall extended structure.

Wong, G F; Crawford, E J; De Horta, A; Galvin, T; Draskovi?, D; Payne, J L

2011-01-01

136

Pattern recognition on brain magnetic resonance imaging in alpha dystroglycanopathies.  

PubMed

Alpha dystroglycanopathies are heterogeneous group of disorders both phenotypically and genetically. A subgroup of these patients has characteristic brain imaging findings. Four patients with typical imaging findings of alpha dystroglycanopathy are reported. Phenotypic features included: global developmental delay, contractures, hypotonia and oculomotor abnormalities in all. Other manifestations were consanguinity (3), seizures (3), macrocephaly (1), microcephaly (3), retinal changes (2) and hypogenitalism (2). Magnetic resonance imaging (MRI) of the brain revealed polymicrogyria, white matter changes, pontine hypoplasia, and subcortical cerebellar cysts in all the patients, ventriculomegaly, callosal abnormalities, and absent septum pellucidum in two and Dandy -Walker variant malformation in three. Magnetic resonace imaging of the first cousin of one the patient had the same characteristic imaging features. Brain imaging findings were almost identical despite heterogeneity in clinical presentation and histopathological features. Pattern recognition of MR imaging features may serve as a clue to the diagnosis of alpha dystroglycanopathy. PMID:20644281

Bindu, Parayil S; Gayathri, Narayanappa; Bharath, Rose D; Mahadevan, Anita; Sinha, Sanjib; Taly, A B

2010-01-01

137

Optical Processing of Speckle Images with Bacteriorhodopsin for Pattern Recognition  

NASA Technical Reports Server (NTRS)

Logarithmic processing of images with multiplicative noise characteristics can be utilized to transform the image into one with an additive noise distribution. This simplifies subsequent image processing steps for applications such as image restoration or correlation for pattern recognition. One particularly common form of multiplicative noise is speckle, for which the logarithmic operation not only produces additive noise, but also makes it of constant variance (signal-independent). We examine the optical transmission properties of some bacteriorhodopsin films here and find them well suited to implement such a pointwise logarithmic transformation optically in a parallel fashion. We present experimental results of the optical conversion of speckle images into transformed images with additive, signal-independent noise statistics using the real-time photochromic properties of bacteriorhodopsin. We provide an example of improved correlation performance in terms of correlation peak signal-to-noise for such a transformed speckle image.

Downie, John D.; Tucker, Deanne (Technical Monitor)

1994-01-01

138

Pattern based 3D image Steganography  

NASA Astrophysics Data System (ADS)

This paper proposes a new high capacity Steganographic scheme using 3D geometric models. The novel algorithm re-triangulates a part of a triangle mesh and embeds the secret information into newly added position of triangle meshes. Up to nine bits of secret data can be embedded into vertices of a triangle without causing any changes in the visual quality and the geometric properties of the cover image. Experimental results show that the proposed algorithm is secure, with high capacity and low distortion rate. Our algorithm also resists against uniform affine transformations such as cropping, rotation and scaling. Also, the performance of the method is compared with other existing 3D Steganography algorithms. [Figure not available: see fulltext.

Thiyagarajan, P.; Natarajan, V.; Aghila, G.; Prasanna Venkatesan, V.; Anitha, R.

2013-03-01

139

Imaging diffuse clouds: bright and dark gas mapped in CO  

NASA Astrophysics Data System (ADS)

Aims: We wish to relate the degree scale structure of galactic diffuse clouds to sub-arcsecond atomic and molecular absorption spectra obtained against extragalactic continuum background sources. Methods: We used the ARO 12 m telescope to map J = 1-0 CO emission at 1' resolution over 30' fields around the positions of 11 background sources occulted by 20 molecular absorption line components, of which 11 had CO emission counterparts. We compared maps of CO emission to sub-arcsec atomic and molecular absorption spectra and to the large-scale distribution of interstellar reddening. Results: 1) The same clouds, identified by their velocity, were seen in absorption and emission and atomic and molecular phases, not necessarily in the same direction. Sub-arcsecond absorption spectra are a preview of what is seen in CO emission away from the continuum. 2) The CO emission structure was amorphous in 9 cases, quasi-periodic or wave-like around B0528+134 and tangled and filamentary around BL Lac. 3) Strong emission, typically 4-5 K at EB - V ? 0.15 mag and up to 10-12 K at EB - V ? 0.3 mag was found, much brighter than toward the background targets. Typical covering factors of individual features at the 1 K km s-1 level were 20%. 4) CO-H2 conversion factors as much as 4-5 times below the mean value N(H2)/WCO = 2 × 1020 H2 cm-2 (K km s-1)-1 are required to explain the luminosity of CO emission at/above the level of 1 K km s-1. Small conversion factors and sharp variability of the conversion factor on arcminute scales are due primarily to CO chemistry and need not represent unresolved variations in reddening or total column density. Conclusions: Like Fermi and Planck we see some gas that is dark in CO and other gas in which CO is overluminous per H2. A standard CO-H2 conversion factor applies overall owing to balance between the luminosities per H2 and surface covering factors of bright and dark CO, but with wide variations between sightlines and across the faces of individual clouds. Based on observations obtained with the ARO Kitt Peak 12 m telescope.Appendices are available in electronic form at http://www.aanda.org

Liszt, H. S.; Pety, J.

2012-05-01

140

Pattern Recognition and Image Processing of Infrared Astronomical Satellite Images  

Microsoft Academic Search

The Infrared Astronomical Satellite (IRAS) images with wavelengths of 60 mu m and 100 mu m contain mainly information on both extra-galactic sources and low-temperature interstellar media. The low-temperature interstellar media in the Milky Way impose a \\

Lun Xiong He

1996-01-01

141

High-speed imaging of blood splatter patterns  

SciTech Connect

The interpretation of blood splatter patterns is an important element in reconstructing the events and circumstances of an accident or crime scene. Unfortunately, the interpretation of patterns and stains formed by blood droplets is not necessarily intuitive and study and analysis are required to arrive at a correct conclusion. A very useful tool in the study of blood splatter patterns is high-speed photography. Scientists at the Los Alamos National Laboratory, Department of Energy (DOE), and Bureau of Forensic Services, State of California, have assembled a high-speed imaging system designed to image blood splatter patterns. The camera employs technology developed by Los Alamos for the underground nuclear testing program and has also been used in a military mine detection program. The camera uses a solid-state CCD sensor operating at approximately 650 frames per second (75 MPixels per second) with a microchannel plate image intensifier that can provide shuttering as short as 5 ns. The images are captured with a laboratory high-speed digitizer and transferred to an IBM compatible PC for display and hard copy output for analysis. The imaging system is described in this paper.

McDonald, T.E.; Albright, K.A.; King, N.S.P.; Yates, G.J. [Los Alamos National Lab., NM (United States); Levine, G.F. [California Dept. of Justice, Sacramento, CA (United States). Bureau of Forensic Services

1993-05-01

142

High-speed imaging of blood splatter patterns  

SciTech Connect

The interpretation of blood splatter patterns is an important element in reconstructing the events and circumstances of an accident or crime scene. Unfortunately, the interpretation of patterns and stains formed by blood droplets is not necessarily intuitive and study and analysis are required to arrive at a correct conclusion. A very useful tool in the study of blood splatter patterns is high-speed photography. Scientists at the Los Alamos National Laboratory, Department of Energy (DOE), and Bureau of Forensic Services, State of California, have assembled a high-speed imaging system designed to image blood splatter patterns. The camera employs technology developed by Los Alamos for the underground nuclear testing program and has also been used in a military mine detection program. The camera uses a solid-state CCD sensor operating at approximately 650 frames per second (75 MPixels per second) with a microchannel plate image intensifier that can provide shuttering as short as 5 ns. The images are captured with a laboratory high-speed digitizer and transferred to an IBM compatible PC for display and hard copy output for analysis. The imaging system is described in this paper.

McDonald, T.E.; Albright, K.A.; King, N.S.P.; Yates, G.J. (Los Alamos National Lab., NM (United States)); Levine, G.F. (California Dept. of Justice, Sacramento, CA (United States). Bureau of Forensic Services)

1993-01-01

143

MARCI Ultraviolet Global Imaging of Mars Ozone and Clouds  

Microsoft Academic Search

The Mars Color Imager (MARCI) experiment onboard the Mars Reconnaissance Orbiter (MRO) incorporates a unique ultraviolet (UV) imaging capability which, coupled with the MARCI wide-angle (180 deg) field-of-view, supports daily global mapping of Mars in two relatively narrow band (30nm FWHM) UV channels. A short wave 260 nm channel is positioned to measure Hartley band ozone absorption relative to a

R. T. Clancy; M. J. Wolff; M. C. Malin

2006-01-01

144

Medical Image Segmentation Based on Biomimetic Pattern Recognition  

Microsoft Academic Search

A medical image segmentation algorithm based on biomimetic pattern recognition is proposed. First, psi3-neurons' weights are determined according to training samples and then multi-weight neuron networks are established. Second, the neuron networks are used to completely cover the samples' high-dimensional feature space. Finally, medical images are recognized and segmented based on the results of the optimal coverage of the samples.

Jiafu Jiang; He Wei; Qi Qi

2009-01-01

145

Cirrus cloud detection from airborne imaging spectrometer data using the 1.38 micron water vapor band  

NASA Technical Reports Server (NTRS)

Using special images acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) at 20 km altitude, we show that wavelengths close to the center of the strong 1.38 micron water vapor band are useful for detecting thin cirrus clouds. The detection makes use of the fact that cirrus clouds are located above almost all the atmospheric water vapor. Because of the strong water vapor absorption in the lower atmosphere, AVIRIS channels near 1.38 micron receive little scattered solar radiance from the surface of low level clouds. When cirrus clouds are present, however, these channels receive large amounts of scattered solar radiance from the cirrus clouds. Our ability to determine cirrus cloud cover using space-based remote sensing will be improved if channels near the center of the 1.38 micron water vapor band are added to future satellites.

Gao, Bo-Cai; Goetz, Alexander F. H.; Wiscombe, Warren J.

1993-01-01

146

Complexity reduced coding of binary pattern units in image classification  

NASA Astrophysics Data System (ADS)

The ability to simulate and control complex physical situations in real time is an important element of many engineering and robotics applications, including pattern recognition and image classification. One of the ways to meet specific requirements of a process is a reduction of computational complexity of algorithms. In this work we propose a new coding of binary pattern units (BPU) that reduces the time and spatial complexity of algorithms of image classification significantly. We apply this coding to a particular but important case of the coordinated clusters representation (CCR) of images. This algorithm reduces the dimension of the CCR feature space and, as a consequence, the time and space complexity of the CCR based methods of image classification, exponentially. In addition, the new coding preserves all the fundamental properties of the CCR that are successfully used in the recognition, classification and segmentation of texture images. The same approach to the coding of BPUs can be used in the Local Binary Pattern (LBP) method. In order to evaluate the reduction of time and space complexity, we did an experiment on multiclass classification of images using the "traditional" and the new coding of the CCR. This test showed very effective reduction of the computing time and required computer memory with the use of the new coding of BPUs of the CCR, retaining 100% or a little less efficiency of classification at the time.

Kurmyshev, E. V.; Guillen-Bonilla, J. T.

2011-06-01

147

Hiding a checkered-pattern carrier-screen image in a camouflaged halftone image  

NASA Astrophysics Data System (ADS)

As carrier-screen images, we have developed checkered-pattern carrier-screen images, which can be physically decoded by superimposing a checkered pattern. We also proposed a decoding method by image sampling with an ordinary compact digital camera. To obtain a better decoding result, each carrier-screen image should be output at a low resolution. However, secret information can be detected when you observe the image carefully. Thus, a hiding process is an important technique. In this paper, we propose an advanced hiding method by embedding the carrier-screen image into another significant image to generate a camouflaged halftone image. The proposed embedding method can be performed through a simple sequential process of blending and halftoning.

Shogenji, Rui; Ohtsubo, Junji

2014-05-01

148

High-resolution imaging of the galactic cloud Monoceros R2  

NASA Technical Reports Server (NTRS)

We present high-resolution images (9.8 arcsec x 8.5 arcsec beam size) of HCO(+) J = 1-0 emission from the Galactic cloud Mon R2 obtained using the Hat Creek millimeter interferometer and the Five College Radio Astronomy Observatory 14 m antenna. The HCO(+) emission comes from small optically thick clumps as well as from an extended component. We discuss the relationship between the H II region, as traced by the continuum emission, molecular outflows, as traced by CO emission, and the dense molecular cloud, as traced by the HCO(+) emission. The abundance of HCO(+) in the most massive part of the cloud is consistent with values derived from recent molecular line surveys, but it is relatively enhanced in the less massive regions.

Gonatas, Constantine P.; Palmer, Patrick; Novak, G.

1992-01-01

149

HARP-B and Wide-Field Imaging of Molecular Clouds  

NASA Astrophysics Data System (ADS)

Molecular clouds within our galaxy provide excellent opportunities to study the processes of star formation in detail. They extend over large regions of the sky, and therefore wide-field imaging is required to capture all of the structure inside them, and to investigate their varied conditions. Performing this task efficiently, in high resolution, and over statistically useful numbers of clouds can best be achieved using array receivers. However these are a relatively new development due to the difficulty of constructing instrumentation for the millimetre and sub-millimetre wavelengths at which molecular clouds emit. Part I of this thesis describes HARP-B - a new heterodyne array receiver operating at 345GHz on the James Clerk Maxwell Telescope. The work described focusses on the optics, interferometer and commissioning of HARP-B. Careful testing and alignment of the optics was necessary to ensure that HARP-B would perform as required. Its Mach-Zehnder interferometer was put under computer control and characterised to allow it to be used as an effective sideband filter. This part concludes with the integration and commissioning of the receiver, leading up to first light. Part II then presents wide-field observations of the IC5146 and L977 molecular clouds, made with HARP-B and other instruments at the JCMT and IRAM 30m telescopes. For IC5146, SCUBA continuum images and a dust extinction map were already available. These were complemented by spectral observations of C18O 1-0, C18O 2-1 and the 3-2 transition of 12CO, 13CO and C18O. The data were used to study the cloud structure, excitation conditions and dust properties. SCUBA continuum and C18O 2-1 observations were made of L977 and analysed along with the existing dust extinction map in order to study the dust and gas properties, and the structure of the molecular cloud.

Bell, Graham S.

2008-10-01

150

Low Clouds and Fog Characterization over Iberian Peninsula using Meteosat Second Generation Images  

NASA Astrophysics Data System (ADS)

Fog is defined as a collection of suspended water droplets or ice crystals in the air near the Earth's surface that lead to a reduction of horizontal visibility below 1 km (National Oceanic and Atmospheric Administration, 1995). Fog is a stratiform cloud with similar radiative characteristics, for this reason the difference between fog and low stratus clouds is of little importance for remote sensing applications. Fog and low clouds are important atmospheric phenomena, mainly because of their impact on traffic safety and air quality, acting as an obstruction to traffic at land, sea and in the air. The purpose of this work is to develop the method of fog/low clouds detection and analysis on nighttime using Meteosat Second Generation data. This study is focused on the characterization of these atmospheric phenomena in different study cases over the Iberian Peninsula with distinct orography. Firstly, fog/low clouds detection is implemented as a composition of three infrared channels 12.0, 10.8 and 3.9 µm from SEVIRI radiometer on board European geostationary satellite Meteosat (Meteosat-9). The algorithm of detection makes use of a combination of these channels and their differences by creating RGB composites images. On this way, it displays the spatial coverage and location of fog entities. Secondly, this technique allows separating pixels which are indicated as fog/low clouds from clear pixels, assessing the properties of individual pixels using appropriated thresholds of brightness temperature. Thus, it achieves a full analysis of the extent and distribution of fog and its evolution over time. The results of this study have been checked by using ground-based point measurements available as METAR data. Despite the flaws in this sort of inter-comparison approach, the outcome produces to accurate fog/low clouds detection. This work encompasses the way to obtain spatial information from this atmospheric phenomenon by means of satellite imagery.

Sánchez, Beatriz; Maqueda, Gregorio

2014-05-01

151

Influence of clouds on the parameters of images measured by IACT at very high energies  

E-print Network

Observations with the Cherenkov telescopes are in principle limited to the clear sky conditions due to significant absorption of Cherenkov light by clouds. If the cloud level is high enough or the atmospheric transmission of the cloud is high, then high energy showers (with TeV energies) can still produce enough Cherenkov photons allowing detection by telescopes with large sizes and cameras with large field of view (FOV). In this paper we study the possibility of observations of showers, induced by high energy particles in the atmosphere, in the presence of clouds which are completely or partially opaque for Cherenkov radiation. We show how the image parameters of the Cherenkov light distribution on the telescope camera are influenced for different opacity and altitude of the cloud. By applying the Monte Carlo simulations, we calculate the scaled LENGTH and WIDTH parameters with the purpose to separate gamma-ray and proton initiated showers in real data. We show, that the high level of the night sky backgroun...

Sobczynska, Dorota

2014-01-01

152

Pattern Recognition Project : Vessel Detection in Retinal Images  

E-print Network

Pattern Recognition Project : Vessel Detection in Retinal Images Instructor: Wei-Yang Lin Due date study. The goal of this project is to provide a hand-on experience in building a vessel detection methods for detecting retinal blood vessel reported in the literature, e.g., [1, 2, 3]. Each group

Lin, Wei-Yang

153

Artificial convolution neural network for medical image pattern recognition  

Microsoft Academic Search

We have developed several training methods in conjunction with a convolution neural network for general medical image pattern recognition. An unconventional method of using rotation and shift invariance is also proposed to enhance the neural net performance. The structure of the artificial neural network is a simplified network structure of the neocognitron. Two-dimensional local connection as a group is the

Shih-chung Ben Lo; Heang-ping Chan; Jyh-shyan Lin; Huai Li; Matthew T. Freedman; Seong K. Mun

1995-01-01

154

Planet Detection Algorithm using Multiple Images with Independent Speckle Patterns  

NASA Astrophysics Data System (ADS)

Current observations in the context of exoplanet searches with coronagraphic instruments have shown that one of the main limitations to high-contrast imaging is due to residual quasi-static speckles. Speckles look like the image of a planet, but they have a different spectral behavior and are optically coherent with the star. All speckles are formed from the same coherent source, the star, and are incoherent with the planet. Moving the DM (or other changes to the optical layout) causes interference and therefore changes in the speckle pattern as seen on the camera. Since the planet light does not interfere with the speckles, the image of the planet remains untouched (except that speckles may appear on top of the planet). This fundamental coherence property of the speckles (and incoherence with the planet light) guides us to develop methods to take advantage of a changing speckle pattern to distinguish a planet from a speckle. We present a model of estimating the intensity of a planet given a point spread function (PSF), and assuming an unknown and locally constant background source as well as photon noise. We use this model to develop a planet detection algorithm similar to matched filtering of the PSF. We are extending the work of image analysis from one image to multiple images presuming an independent source of aberrations between images.

Young, Elizabeth; Kasdin, N. J.; Carlotti, A.

2012-01-01

155

Directional binary wavelet patterns for biomedical image indexing and retrieval.  

PubMed

A new algorithm for medical image retrieval is presented in the paper. An 8-bit grayscale image is divided into eight binary bit-planes, and then binary wavelet transform (BWT) which is similar to the lifting scheme in real wavelet transform (RWT) is performed on each bitplane to extract the multi-resolution binary images. The local binary pattern (LBP) features are extracted from the resultant BWT sub-bands. Three experiments have been carried out for proving the effectiveness of the proposed algorithm. Out of which two are meant for medical image retrieval and one for face retrieval. It is further mentioned that the database considered for three experiments are OASIS magnetic resonance imaging (MRI) database, NEMA computer tomography (CT) database and PolyU-NIRFD face database. The results after investigation shows a significant improvement in terms of their evaluation measures as compared to LBP and LBP with Gabor transform. PMID:21822675

Murala, Subrahmanyam; Maheshwari, R P; Balasubramanian, R

2012-10-01

156

Venus Cloud Particle Size Distributions and Altitudes from IRTF/SpeX Spectral Image Cubes  

NASA Astrophysics Data System (ADS)

Absorption of infrared radition at 1.10, 1.18, 1.31, 1.74, and 2.3 ?m due to molecular gas electronic transitions is minimal through the Venus atmosphere. Blackbody radiation from the surface and deep atmosphere, observed on the night side, is therefore mostly affected by cloud aerosols. Ratios of the observed fluxes in each of these windows provide information on the scatterers’ sizes. Altitudes can be derived by the use of forward modeling to simulate the observed temperatures and fluxes. We use IRTF/SpeX spectra of the nightside of Venus we obtained in July and September 2007, simultaneous with Venus Express VIRTIS observations of the southern hemisphere at the same wavelengths. By allowing the 60” spectrometer slit to drift across Venus’ night side over approximately 15 minutes, we acquired spectral image cubes comprised of about 100 spectra, from 0.8 to 2.5 ?m with a spectral resolution of R 400. We use a multiple scattering line-by-line radiative transfer code and the HITRAN 2004 and HITEMP databases to calculate the fluxes in each window for a range of cloud structure and altitudes. Ratios of fluxes in each of the windows that are diagnostic of cloud particle distributions are compared with these ratios in our spectral image cubes. By obtaining a least squares best fit to the data, we produce maps of particle sizes and altitudes of the Venus clouds.

Bullock, Mark Alan; Young, E. F.; McGouldrick, K.

2009-09-01

157

Accelerating statistical image reconstruction algorithms for fan-beam x-ray CT using cloud computing  

NASA Astrophysics Data System (ADS)

Statistical image reconstruction algorithms potentially offer many advantages to x-ray computed tomography (CT), e.g. lower radiation dose. But, their adoption in practical CT scanners requires extra computation power, which is traditionally provided by incorporating additional computing hardware (e.g. CPU-clusters, GPUs, FPGAs etc.) into a scanner. An alternative solution is to access the required computation power over the internet from a cloud computing service, which is orders-of-magnitude more cost-effective. This is because users only pay a small pay-as-you-go fee for the computation resources used (i.e. CPU time, storage etc.), and completely avoid purchase, maintenance and upgrade costs. In this paper, we investigate the benefits and shortcomings of using cloud computing for statistical image reconstruction. We parallelized the most time-consuming parts of our application, the forward and back projectors, using MapReduce, the standard parallelization library on clouds. From preliminary investigations, we found that a large speedup is possible at a very low cost. But, communication overheads inside MapReduce can limit the maximum speedup, and a better MapReduce implementation might become necessary in the future. All the experiments for this paper, including development and testing, were completed on the Amazon Elastic Compute Cloud (EC2) for less than $20.

Srivastava, Somesh; Rao, A. Ravishankar; Sheinin, Vadim

2011-03-01

158

BlobCR: Efficient Checkpoint-Restart for HPC Applications on IaaS Clouds using Virtual Disk Image Snapshots  

E-print Network

BlobCR: Efficient Checkpoint-Restart for HPC Applications on IaaS Clouds using Virtual Disk Image is gain- ing increasing attention for a wide range of scientific high performance computing (HPC that there is an increasing improvement in the scalability and perfor- mance of cloud-based HPC systems [19]. Furthermore, un

Paris-Sud XI, Université de

159

Character and pattern recognition based on moire images  

NASA Astrophysics Data System (ADS)

The paper presents a novel method for recognizing raised or indented characters or patterns on industrial samples by using a combination of moire interferometry technique with optical character recognition (OCR) and pattern recognition. Patterns recognized with this method are of low contrast, and conventional recognition schemes require complex optics and lighting. Raised characters on tires, vin code tags, credit cards, indented characters on metal, wrinkles on skin, and embossment on buttons are some examples. The proposed method uses the moire interferometry technique to obtain a gray scale image of patterns such that their heights are represented in gray scale. This eliminates the need for special optics for each application. 3D images obtained as above, are processed by three sets of algorithms: 1) analytical geometry, 2) pattern recognition, and 3) character recognition. The analytical geometry algorithms consist of constrained and unconstrained fitting methods for scattered data, and transformations between different spaces. The pattern recognition methods consist of feature extraction based on scatter matrices, and classification based on hierarchic classification methods. The OCR algorithm employs gray scale correlation. Extension experiments are conducted to support the method.

Chatterjee, Chanchal; Bieman, Leonard H.

1995-08-01

160

Photometric Calibration of the Barium Cloud Image in a Space Active Experiment: Determining the Release Efficiency  

NASA Astrophysics Data System (ADS)

The barium release experiment is an effective method to explore the near-earth environment and to study all kinds of space physics processes. The first space barium release experiment in China was successfully carried out by a sounding rocket on April 5, 2013. This work is devoted to calculating the release efficiency of the barium release by analyzing the optical image observed during the experiment. First, we present a method to calibrate the images grey value of barium cloud with the reference stars to obtain the radiant fluxes at different moments. Then the release efficiency is obtained by a curve fitting with the theoretical evolution model of barium cloud. The calculated result is basically consistent with the test value on ground.

Xie, Liang-Hai; Li, Lei; Wang, Jing-Dong; Tao, Ran; Cheng, Bing-Jun; Zhang, Yi-Teng

2014-01-01

161

Morphological Characteristics of Compact High-Velocity Clouds Revealed by High-Resolution WSRT Imaging  

E-print Network

A class of compact, isolated high-velocity clouds which plausibly represents a homogeneous subsample of the HVC phenomenon in a single physical state was objectively identified by Braun and Burton (1999). Six examples of the CHVCs, unresolved in single-dish data, have been imaged with the Westerbork Synthesis Radio Telescope. The high-resolution imaging reveals the morphology of these objects, including a core/halo distribution of fluxes, signatures of rotation indicating dark matter, and narrow linewidths constraining the kinetic temperature of several opaque cores. In these regards, as well as in their kinematic and spatial deployment on the sky, the CHVC objects are evidently a dynamically cold ensemble of dark-matter-dominated HI clouds accreting onto the Local Group in a continuing process of galactic evolution.

W. B. Burton; Robert Braun

1999-12-22

162

Infrared Cloud Imager Development for Atmospheric Optical Communication Characterization, and Measurements at the JPL Table Mountain Facility  

NASA Astrophysics Data System (ADS)

The continuous demand for high data return in deep space and near-Earth satellite missions has led NASA and international institutions to consider alternative technologies for high-data-rate communications. One solution is the establishment of wide-bandwidth Earth-space optical communication links, which require (among other things) a nearly obstruction-free atmospheric path. Considering the atmospheric channel, the most common and most apparent impairments on Earth-space optical communication paths arise from clouds. Therefore, the characterization of the statistical behavior of cloud coverage for optical communication ground station candidate sites is of vital importance. In this article, we describe the development and deployment of a ground-based, long-wavelength infrared cloud imaging system able to monitor and characterize the cloud coverage. This system is based on a commercially available camera with a 62-deg diagonal field of view. A novel internal-shutter-based calibration technique allows radiometric calibration of the camera, which operates without a thermoelectric cooler. This cloud imaging system provides continuous day-night cloud detection with constant sensitivity. The cloud imaging system also includes data-processing algorithms that calculate and remove atmospheric emission to isolate cloud signatures, and enable classification of clouds according to their optical attenuation. Measurements of long-wavelength infrared cloud radiance are used to retrieve the optical attenuation (cloud optical depth due to absorption and scattering) in the wavelength range of interest from visible to near-infrared, where the cloud attenuation is quite constant. This article addresses the specifics of the operation, calibration, and data processing of the imaging system that was deployed at the NASA/JPL Table Mountain Facility (TMF) in California. Data are reported from July 2008 to July 2010. These data describe seasonal variability in cloud cover at the TMF site, with cloud amount (percentage of cloudy pixels) peaking at just over 51 percent during February, of which more than 60 percent had optical attenuation exceeding 12 dB at wavelengths in the range from the visible to the near-infrared. The lowest cloud amount was found during August, averaging 19.6 percent, and these clouds were mostly optically thin, with low attenuation.

Nugent, P. W.; Shaw, J. A.; Piazzolla, S.

2013-02-01

163

Near-Infrared Polarization Images of The Orion Molecular Cloud 1 South Region  

E-print Network

We present the polarization images in the $J$, $H$, & $Ks$ bands of the Orion Molecular Cloud 1 South region. The polarization images clearly show at least six infrared reflection nebulae (IRNe) which are barely seen or invisible in the intensity images. Our polarization vector images also identify the illuminating sources of the nebulae: IRN 1 & 2, IRN 3, 4, & 5, and IRN 6 are illuminated by three IR sources, Source 144-351, Source 145-356, and Source 136-355, respectively. Moreover, our polarization images suggest the candidate driving sources of the optical Herbig-Haro objects for the first time; HH529, a pair of HH202 and HH528 or HH 203/204, HH 530 and HH269 are originated from Source 144-351, Source 145-356, and Source 136-355, respectively.

Jun Hashimoto; Motohide Tamura; Ryo Kandori; Nobuhiko Kusakabe; Yasushi Nakajima; Shuji Sato; Chie Nagashima; Mikio Kurita; Tetsuya Nagata; Takahiro Nagayama; Jim Hough

2006-12-18

164

A Near-Infrared Imaging Survey of the Chamaeleon I Dark Cloud  

E-print Network

We describe a near-infrared imaging survey covering approximately 1 square deg of the Chamaeleon I dark cloud. The survey is complete for K 12.0, based on their positions in the J-H, H-K color-color diagram. These new stars have low luminosities (K > 12 -- 16, H-K > 0.5 -- 1.5) and may have masses close to or even below the hydrogen burning limit.

M. Gomez; S. J. Kenyon

2000-11-05

165

Implementation of MapReduce-based image conversion module in cloud computing environment  

Microsoft Academic Search

In recent years, the rapid advancement of the Internet and the growing number of people using social networking services (SNSs) have facilitated the sharing of multimedia data. However, multimedia data processing techniques such as transcoding and transmoding impose a considerable burden on the computing infrastructure as the amount of data increases. Therefore, we propose a MapReduce-based image-conversion module in cloud

Hyeokju Lee; Myoungjin Kim; Joon Her; Hanku Lee

2012-01-01

166

Holographic images reconstructed from GMR-based fringe pattern  

NASA Astrophysics Data System (ADS)

We have developed a magneto-optical spatial light modulator (MOSLM) using giant magneto-resistance (GMR) structures for realizing a holographic three-dimensional (3D) display. For practical applications, reconstructed image of hologram consisting of GMR structures should be investigated in order to study the feasibility of the MOSLM. In this study, we fabricated a hologram with GMR based fringe-pattern and demonstrated a reconstructed image. A fringe-pattern convolving a crossshaped image was calculated by a conventional binary computer generated hologram (CGH) technique. The CGH-pattern has 2,048 × 2,048 with 5 ?m pixel pitch. The GMR stack consists of a Tb-Fe-Co/CoFe pinned layer, a Ag spacer, a Gd-Fe free layer for light modulation, and a Ru capping layer, was deposited by dc-magnetron sputtering. The GMR hologram was formed using photo-lithography and Krion milling processes, followed by the deposition of a Tb-Fe-Co reference layer with large coercivity and the same Kerr-rotation angle compared to the free layer, and a lift-off process. The reconstructed image of the ON-state was clearly observed and successfully distinguished from the OFF-state by switching the magnetization direction of the free-layer with an external magnetic field. These results indicate the possibility of realizing a holographic 3D display by the MOSLM using the GMR structures.

Kato, Daisuke; Aoshima, Kenichi; Machida, Kenji; Emoto, Akira; Kinjo, Hidekazu; Kuga, Kiyoshi; Ono, Hiroshi; Ishibashi, Takayuki; Kikuchi, Hiroshi; Shimidzu, Naoki

2013-01-01

167

MR Imaging of Spinal Nerve Roots:Techniques, Enhancement Patterns, and Imaging Findings  

Microsoft Academic Search

The purpose of this report was to review the MR techniques, contrast enhancement patterns, and MR imaging findings for the spinal nerve roots. The phenomenon of contrast enhance- ment of the nerve roots and its relationship to disk disease and failed-back-surgery syndrome are discussed. The MR imaging findings for various inflammatory and neoplastic disorders affecting the spinal nerve roots are

Bassem A. Georgy; Ruth D. Snow; John R. HesSelink

168

Cloud Ozone Dust Imager (CODI). Volume 1; Investigation and Technical Plan  

NASA Technical Reports Server (NTRS)

The Cloud Ozone Dust Imager (CODI) is proposed to investigate the current climatic balance of the Mars atmosphere, with particular emphasis on the important but poorly understood roles which dust and water ice aerosols play in this balance. The large atmospheric heating (20-50 K) resulting from global dust storms around Mars perihelion is well recognized. However, groundbased observations of Mars atmospheric temperatures, water vapor, and clouds since the Viking missions have identified a much colder, cloudier atmosphere around Mars aphelion that may prove as important as global dust storms in determining the interannual and long-term behavior of the Mars climate. The key climate issues CODI is designed to investigate are: 1) the degree to which non-linear interactions between atmospheric dust heating, water vapor saturation, and cloud nucleation influence the seasonal and interannual variability of the Mars atmosphere, and 2) whether the strong orbital forcing of atmospheric dust loading, temperatures and water vapor saturation determines the long-term balance of Mars water, as reflected in the north-south hemispheric asymmetries of atmospheric water vapor and polar water ice abundances. The CODI experiment will measure the daily, seasonal and (potentially) interannual variability of atmospheric dust and cloud opacities, and the key physical properties of these aerosols which determine their role in the climate cycles of Mars. CODI is a small (1.2 kg), fixed pointing camera, in which four wide-angle (+/- 70 deg) lenses illuminate fixed filters and CCD arrays. Simultaneous sky/surface imaging of Mars is obtained at an angular resolution of 0.28 deg/pixel for wavelengths of 255, 336, 502, and 673 nm (similar to Hubble Space Telescope filters). These wavelengths serve to measure atmospheric ozone (255 and 336 nm), discriminate ice and dust aerosols (336 and 673 nm), and construct color images (336, 502, and 673 nm). The CODI images are detected on four 512 x 512 pixel arrays, as partitioned on two 1024 x 1024 CCD's operated in frame transfer mode. The center of the CODI field-of-view is canted 40 deg from the zenith direction to obtain sky brightness measurements and a 20 deg surface field-of-view. Daily image observations will be conducted when the Sun is greater than or equal to 5 deg outside the edge of the CODI field-of-view, and twilight and nighttime imaging will obtained on a weekly basis. The 673 nm channel includes a polarizer wheel to obtain sky/surface polarimetry. A dust cover protects the entire lens assemblies of all four CODI channels. This opaque dust cover, which is normally opened for CODI imaging, includes a small fixed mirror and transparent window positioned above the 673 nm lens, to redirect the 673 nm field-of-view to the surface for descent imaging. Fixed pointing, internal data buffering, low operating power (2-4 W for less than or equal to 30 seconds), selective data transmission, and simple operational characteristics of the CODI experiment place minimum resource and operational demands on the Mars Surveyor 1998 lander. The CODI science goals are optimized for, but not restricted to, a low-latitude landing site (20 deg S-30 deg N). The primary CODI measurement objectives are the opacities, wave forms, particle properties (size, shape, and alignment), and heights of clouds; the opacities, particle properties, and vertical distribution of dust; and the opacity and vertical distribution of ozone. The variability of cloud, ozone, and dust opacities will be determined on diurnal, daily, and seasonal timescales. Wind velocities will be determined from cloud motions and wave characteristics; and the temporal variability of atmospheric water vapor, with limited altitude information, will be inferred from the CODI ozone observations. Secondary measurement objectives include limited descent imaging capability, surface uv-visible photometry and polarimetry, photochemistry, and meteorite infall rates.

Clancy, R. Todd; Dusenbery, Paul; Wolff, Michael; James, Phil; Allen, Mark; Goguen, Jay; Kahn, Ralph; Gladstone, Rany; Murphy, Jim

1995-01-01

169

Physical and statistical approaches for cloud identification using Meteosat Second Generation-Spinning Enhanced Visible and Infrared Imager Data  

Microsoft Academic Search

In this paper a cloud detection algorithm applied to the MSG-SEVIRI (Meteosat Second Generation-Spinning Enhanced Visible and Infrared Imager) data is described. In order to obtain a good performance in cloud detection, physical, statistical and temporal approaches have been used. In the statistical algorithm, the spectral and textural features of the MSG-SEVIRI images have been used as input, while, in

E. Ricciardelli; F. Romano; V. Cuomo

2008-01-01

170

Cloud patterns lee of Hawaii Island: A synthesis of satellite observations and numerical simulation  

NASA Astrophysics Data System (ADS)

Standing well above the trade wind inversion, Hawaii Island (maximum elevation ˜4.2 km) splits the northeast trade winds and induces a westerly reverse flow in the wake. Satellite observations and regional model simulations are used to investigate circulation effects on lee cloud formation during summer. Over the island, the cloud distribution is consistent with orographic-induced vertical motions. Over the lee ocean, our analysis reveals a cloud band that extends southwestward over a few tens of kilometers from the southwest coast of the island. This southwest lee cloud band is most pronounced in the afternoon, anchored by strong convergence and maintained by in situ cloud production in the upward motion. Such an offshore cloud band is not found off the northwest coast, an asymmetry possibly due to the Coriolis effect on the orographic flow. Off the Kona coast, the dynamically induced westerly reverse flow keeps the wake cool and nearly free of clouds during the day. Along the Kona coast, clouds are blown offshore from the island by the easterly trades in the afternoon in a layer above the reverse flow. Deprived of in situ production, these afternoon Kona coast clouds dissipate rapidly offshore. At night, the offshore land/valley breezes converge onto the onshore reverse flow, and a cloud deck forms on and off the Kona coast, bringing nighttime rain as observed at land stations. To illustrate the circulation effect, lee cloud formation is compared between tall Hawaii and short Kauai/Oahu Islands, which feature the flow-around and flow-over regimes, respectively. Effects of trade wind strength on the leeside cloudiness are also studied.

Yang, Yang; Xie, Shang-Ping; Hafner, Jan

2008-08-01

171

Component pattern analysis of chemicals using multispectral THz imaging system  

NASA Astrophysics Data System (ADS)

We have developed a novel basic technology for terahertz (THz) imaging, which allows detection and identification of chemicals by introducing the component spatial pattern analysis. The spatial distributions of the chemicals were obtained from terahertz multispectral transillumination images, using absorption spectra previously measured with a widely tunable THz-wave parametric oscillator. Further we have applied this technique to the detection and identification of illicit drugs concealed in envelopes. The samples we used were methamphetamine and MDMA, two of the most widely consumed illegal drugs in Japan, and aspirin as a reference.

Kawase, Kodo; Ogawa, Yuichi; Watanabe, Yuki

2004-04-01

172

IMAGE RELEASE: New Hydrogen Clouds in the M81 Group of Galaxies  

NASA Astrophysics Data System (ADS)

A composite radio-optical image shows five new clouds of hydrogen gas discovered using the National Science Foundation's Robert C. Byrd Green Bank Telescope (GBT). The spiral galaxy M81 and its satellite, M82, are seen in visible light (white); intergalactic hydrogen gas revealed by the GBT is shown in red; and additional hydrogen gas earlier detected by the Very Large Array is shown in green. The M81 Group of galaxies, 11.8 million light-years from Earth, are interacting gravitationally with each other, as shown clearly by the gas streaming among them. The newly-discovered gas clouds, each containing from 14 to 57 million times the mass of our Sun, are similar to gas clouds also found near our own Milky Way Galaxy. Astronomers analyzing these M81 Group clouds conclude that they are likely remnants of earlier interactions among the galaxies and that this indicates that their analogs near the Milky Way had a similar origin. The research team is: Katie Chynoweth, a graduate student at Vanderbilt University; Glen Langston of the National Radio Astronomy Observatory (NRAO); Min Yun of the University of Massachusetts; Felix J. Lockman of NRAO; Kate Rubin of Lick Observatory; and Sarah Scoles of Cornell University. The astronomers presented their findings to the American Astronomical Society's meeting in Austin, Texas. Credit: Chynoweth et al., NRAO/AUI/NSF, Digital Sky Survey. The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

2008-01-01

173

Graph Matching Iris Image Blocks with Local Binary Pattern  

Microsoft Academic Search

Abstract. Iris-based personal identification has attracted much ,attention in re- cent years. Almost all the state-of-the-art iris recognition algorithms are based onstatistical classifier and local image features, which are noise sensitive and hardly to deliver perfect recognition performance. In this paper, we propose a novel iris recognition method, using the histogram of local binary pattern for global iris texture representation

Zhenan Sun; Tieniu Tan; Xianchao Qiu

2006-01-01

174

Watershed image segmentation and cloud classification from multispectral MSG-SEVIRI imagery  

NASA Astrophysics Data System (ADS)

In this work a technique for cloud detection and classification from MSG-SEVIRI (Meteosat Second Generation-Spinning Enhanced Visible and Infra-red Imager) imagery is presented. It is based on the segmentation of the multispectral images using order-invariant watershed algorithms, which are applied to the corresponding gradient images, computed by a multi-dimensional morphological operator. To reduce the over-segmentation produced by the watershed method, a RAG (Region Adjacency Graph) based region merging technique is applied, using region dissimilarity functions. Once the objects present in the image have been segmented, they are classified using a multi-threshold method based on physical considerations that takes into account the statistical parameters inside each region.

González, Albano; Pérez, Juan C.; Muñoz, Jonathan; Méndez, Zebensui; Armas, Montserrat

2012-01-01

175

Hybrid optical/digital image pattern recognition - A review  

NASA Astrophysics Data System (ADS)

The architectures, algorithms, and system fabrication of hybrid pattern recognition processors are reviewed. The basic operations achievable in optical systems, two classic optical pattern recognition (OPR) architectures, and conventional feature-based pattern recognition are reviewed. Various optical architectures for feature extraction are discussed, and results obtained with these system concepts are examined. Various new correlator approaches to distortion-invariant OPR are briefly reviewed together with Artificial Intelligence/Image Understanding (AI/IU) research and subpixel target identification research. Synthetic discriminant function techniques to achieve various distortion-invariant 3-D object recognition are described, stressing new results and efficient phase-only and computer-generated hologram techniques to synthesize such filters. System fabrication issues are discussed, emphasizing new results and flight tests on compact architectures and systems for OPR.

Casasent, D.

1985-01-01

176

An Efficient Pattern Substitution Watermarking Method for Binary Images  

NASA Astrophysics Data System (ADS)

In this paper, a method to decrease the size of location map for non-overlapping pattern substitution method is presented. Original pattern substitution (PS) method has been proposed by Ho et al.[1] as a reversible watermarking scheme for binary images. They use a pair of two patterns to embed data. Unfortunately, their location map is huge in size. In our method, we propose an efficient mechanism which can decrease the size of location map considerably for un-overlapping version of the PS method. Experiment results show that our method works well on decreasing the size of location map. Comparison results with the original PS method demonstrate that the proposed method achieves more embedding capacity and higher PSNR value due to the reduced size of the location map.

Dong, Keming; Kim, Hyoung-Joong

177

Multi Spectral Pushbroom Imaging Radiometer (MPIR) for remote sensing cloud studies  

SciTech Connect

A Multi Spectral Pushbroom Imaging Radiometer (MPIR) has been developed as are relatively inexpensive ({approximately}$IM/copy), well-calibrated,imaging radiometer for aircraft studies of cloud properties. The instrument is designed to fly on an Unmanned Aerospace Vehicle (UAV) platform at altitudes from the surface up to 20 km. MPIR is being developed to support the Unmanned Aerospace Vehicle portion of the Department of Energy`s Atmospheric Radiation Measurements program (ARM/UAV). Radiation-cloud interactions are the dominant uncertainty in the current General Circulation Models used for atmospheric climate studies. Reduction of this uncertainty is a top scientific priority of the US Global Change Research Program and the ARM program. While the DOE`s ARM program measures a num-ber of parameters from the ground-based Clouds and Radiation Testbed sites, it was recognized from the outset that other key parameters are best measured by sustained airborne data taking. These measurements are critical in our understanding of global change issues as well as for improved atmospheric and near space weather forecasting applications.

Phipps, G.S.; Grotbeck, C.L.

1995-10-01

178

Synergistic combination of clinical and imaging features predicts abnormal imaging patterns of pulmonary infections  

PubMed Central

We designed and tested a novel hybrid statistical model that accepts radiologic image features and clinical variables, and integrates this information in order to automatically predict abnormalities in chest computed-tomography (CT) scans and identify potentially important infectious disease biomarkers. In 200 patients, 160 with various pulmonary infections and 40 healthy controls, we extracted 34 clinical variables from laboratory tests and 25 textural features from CT images. From the CT scans, pleural effusion (PE), linear opacity (or thickening) (LT), tree-in-bud (TIB), pulmonary nodules, ground glass opacity (GGO), and consolidation abnormality patterns were analyzed and predicted through clinical, textural (imaging), or combined attributes. The presence and severity of each abnormality pattern was validated by visual analysis of the CT scans. The proposed biomarker identification system included two important steps: (i) a coarse identification of an abnormal imaging pattern by adaptively selected features (AmRMR), and (ii) a fine selection of the most important features from the previous step, and assigning them as biomarkers, depending on the prediction accuracy. Selected biomarkers were used to classify normal and abnormal patterns by using a boosted decision tree (BDT) classifier. For all abnormal imaging patterns, an average prediction accuracy of 76.15% was obtained. Experimental results demonstrated that our proposed biomarker identification approach is promising and may advance the data processing in clinical pulmonary infection research and diagnostic techniques. PMID:23930819

Bagci, Ulas; Jaster-Miller, Kirsten; Olivier, Kenneth N.; Yao, Jianhua; Mollura, Daniel J.

2013-01-01

179

Investigating the Effects of Water Ice Cloud Radiative Forcing on the Predicted Patterns and Strength of Dust Lifting on Mars  

NASA Astrophysics Data System (ADS)

The dust cycle is critical for the current Mars climate system because airborne dust significantly influences the thermal and dynamical structure of the atmosphere. The atmospheric dust loading varies with season and exhibits variability on a range of spatial and temporal scales. Until recently, interactive dust cycle modeling studies that include the lifting, transport, and sedimentation of radiatively active dust have not included the formation or radiative effects of water ice clouds. While the simulated patterns of dust lifting and global dust loading from these investigations of the dust cycle in isolation reproduce some characteristics of the observed dust cycle, there are also marked differences between the predictions and the observations. Water ice clouds can influence when, where, and how much dust is lifted from the surface by altering the thermal structure of the atmosphere and the character and strength of the general circulation. Using an updated version of the NASA Ames Mars Global Climate Model (GCM), we show that including water ice cloud formation and their radiative effects affect the magnitude and spatial extent of dust lifting, particularly in the northern hemisphere during the pre- and post- winter solstitial seasons. Feedbacks between dust lifting, cloud formation, circulation intensification and further dust lifting are isolated and shown to be important for improving the behavior of the simulated dust cycle.

Kahre, Melinda A.; Hollingsworth, Jeffery L.; Haberle, Robert M.

2014-11-01

180

Internal variability and pattern identification in cirrus cloud structure: The Fokker-Planck equation approach  

Microsoft Academic Search

Using 35-GHz millimeter wave radar observations collected at the Southern Great Plains site of the Atmospheric Radiation Measurements (ARM) program, we study physical processes in cirrus cloud layers having different stratifications. The time-dependent probability distribution functions of the backscattering cross section within different layers in the cloud describe the dynamics of the pertinent physical processes. The time-dependent tails of the

K. Ivanova; H. N. Shirer; E. E. Clothiaux

2006-01-01

181

Wide-angle imaging LIDAR (WAIL): a ground-based instrument for monitoring the thickness and density of optically thick clouds  

Microsoft Academic Search

Traditional lidar provides little information on dense clouds beyond the range to their base (ceilometry), due to their extreme opacity. At most optical wavelengths, however, laser photons are not absorbed but merely scattered out of the beam, and thus eventually escape the cloud via multiple scattering, producing distinctive extended space- and time-dependent patterns which are, in essence, the cloud's radiative

Steven P. Love; A. B. Davis; C. A. Rohde; Cheng Ho

2001-01-01

182

Optical imaging of cloud-to-stratosphere/mesosphere lightning over the Amazon Basin (CS/LAB)  

NASA Technical Reports Server (NTRS)

The purpose of the CS/LAB project was to obtain images of cloud to stratosphere lightning discharges from aboard NASA's DC-8 Airborne Laboratory while flying in the vicinity of thunderstorms over the Amazon Basin. We devised a low light level imaging package as an add-on experiment to an airborne Laboratory deployment to South America during May-June, 1993. We were not successful in obtaining the desired images during the South American deployment. However, in a follow up flight over the American Midwest during the night of July 8-9, 1993 we recorded nineteen examples of the events over intense thunderstorms. From the observations were estimated absolute brightness, terminal altitudes, flash duration, horizontal extents, emission volumes, and frequencies relative to negative and positive ground strokes.

Sentman, Davis D.; Wescott, Eugene M.

1995-01-01

183

Cirrus cloud characteristics derived from volume imaging lidar, high spectral resolution lidar, HIS radiometer, and satellite  

NASA Technical Reports Server (NTRS)

Preliminary measurement results are presented from the Cirrus Remote Sensing Pilot Experiment which used a unique suite of instruments to simultaneously retrieve cirrus cloud visible and IR optical properties, while addressing the disparities between satellite volume averages and local point measurements. The experiment employed a ground-based high resolution interferometer sounder (HIS) and a second Fourier transform spectrometer to measure the spectral radiance in the 4-20 micron band, a correlated high spectral resolution lidar, a volume imaging lidar, a CLASS radiosonde system, the Scripps Whole Sky Imager, and multispectral VAS, HIRS, and AVHRR satellite data from polar orbiting and geostationary satellites. Data acquired during the month long experiment included continuous daytime monitoring with the Whole Sky Imager.

Grund, Christian J.; Ackerman, Steven A.; Eloranta, Edwin W.; Knutsen, Robert O.; Revercomb, Henry E.; Smith, William L.; Wylie, Donald P.

1990-01-01

184

Combined remote sensing of cloud characteristics with surface-based radar, lidar, and all sky imagers over Beijing, China  

NASA Astrophysics Data System (ADS)

Clouds have been known as the key components of atmospheric processes in climate, weather, and environment related issues. Owing to its highly complicated processes relating to atmospheric dynamic, macro and microphysical characteristics reveal distinct regional and seasonal features, thus observations at various typical sites are very important to quantitatively understand cloud characteristics with their functions. In this paper, we introduce combined ground-based instruments, i.e., a Mie Lidar, a Ka-band Doppler radar, an IR and a visible all sky imagers, and an automatic weather station, to continuously observe the clouds over Beijing. Synthetic analyses are made to derive the cloud base height, vertical structure, horizontal distribution, radiative effect, etc. About 1 year observation data are used to obtain the statistics of cloud characteristics in this area. A simple introduction of the surface-based remote sensing system and some preliminary results are given.

Liu, Jinli; Lu, Daren; Bi, Yongheng; Duan, Shu; Yang, Yong; Pan, Yubin; Li, Yu

2013-05-01

185

High-resolution imaging and target designation through clouds or smoke  

DOEpatents

A method and system of combining gated intensifiers and advances in solid-state, short-pulse laser technology, compact systems capable of producing high resolution (i.e., approximately less than 20 centimeters) optical images through a scattering medium such as dense clouds, fog, smoke, etc. may be achieved from air or ground based platforms. Laser target designation through a scattering medium is also enabled by utilizing a short pulse illumination laser and a relatively minor change to the detectors on laser guided munitions.

Perry, Michael D. (Downy, CA)

2003-01-01

186

A Cost-Benefit Study of Doing Astrophysics On The Cloud: Production of Image Mosaics  

NASA Astrophysics Data System (ADS)

Utility grids such as the Amazon EC2 and Amazon S3 clouds offer computational and storage resources that can be used on-demand for a fee by compute- and data-intensive applications. The cost of running an application on such a cloud depends on the compute, storage and communication resources it will provision and consume. Different execution plans of the same application may result in significantly different costs. We studied via simulation the cost performance trade-offs of different execution and resource provisioning plans by creating, under the Amazon cloud fee structure, mosaics with the Montage image mosaic engine, a widely used data- and compute-intensive application. Specifically, we studied the cost of building mosaics of 2MASS data that have sizes of 1, 2 and 4 square degrees, and a 2MASS all-sky mosaic. These are examples of mosaics commonly generated by astronomers. We also study these trade-offs in the context of the storage and communication fees of Amazon S3 when used for long-term application data archiving. Our results show that by provisioning the right amount of storage and compute resources cost can be significantly reduced with no significant impact on application performance.

Berriman, G. B.; Good, J. C. Deelman, E.; Singh, G. Livny, M.

2009-09-01

187

Airborne Digital In-Line Holographic System for 3-D Imaging of Cloud Particles  

NASA Astrophysics Data System (ADS)

We have developed an airborne holographic instrument for obtaining cloud particle sizes and shapes and their three-dimensional spatial distribution. The primary scientific motivation for the instrument is to provide in-situ measurements of cloud particle spatial correlations, conditioned on particle size. Accurate quantification of spatial correlations at cm-scales and below has been elusive, in part because only one-dimensional spacing data have been available. The optical technique used in the instrument is based on `in-line holography,' where the same collimated light source serves as both the reference beam and the object beam. The system is completely digital, including the capture of holograms using a CCD array, transmission of the data via optical fiber, and subsequent reconstruction of the real image. During the recent IDEAS-3 field project hosted by the NCAR Research Aviation Facility the instrument was tested in flight for the first time, where holograms containing populations of cloud droplets, drizzle drops, and ice crystals were obtained.

Fugal, J. P.; Saw, E.; Sergeyev, A. V.; Shaw, R. A.

2003-12-01

188

Using Geotags to Derive Rich Tag-Clouds for Image Annotation  

NASA Astrophysics Data System (ADS)

Geotagging has become popular for many multimedia applications. In this chapter, we present an integrated and intuitive system for location-driven tag suggestion, in the form of tag-clouds, for geotagged photos. Potential tags from multiple sources are extracted and weighted. Sources include points of interest (POI) tags from a public Geographic Names Information System (GNIS) database, community tags from Flickr® pictures, and personal tags shared through users' own, family, and friends' photo collections. To increase the effectiveness of GNIS POI tags, bags of place-name tags are first retrieved, clustered, and then re-ranked using a combined tf-idf and spatial distance criteria. The community tags from photos taken in the vicinity of the input geotagged photo are ranked according to distance and visual similarity to the input photo. Personal tags from other personally related photos inherently carry a significant weight due more to their high relevance than to both the generic place-name tags and community tags, and are ranked by weights that decay over time and distance differences. Finally, a rich set of the most relevant location-driven tags is presented to the user in the form of individual tag clouds under the three mentioned source categories. The tag clouds act as intuitive suggestions for tagging an input image. We also discuss quantitative and qualitative findings from a user study that we conducted. Evaluation has revealed the respective benefits of the three categories toward the effectiveness of the integrated tag suggestion system.

Joshi, Dhiraj; Luo, Jiebo; Yu, Jie; Lei, Phoury; Gallagher, Andrew

189

Two methods for retrieving UV index for all cloud conditions from sky imager products or total SW radiation measurements.  

PubMed

Cloud effects on UV Index (UVI) and total solar radiation (TR) as a function of cloud cover and sunny conditions (from sky images) as well as of solar zenith angle (SZA) are assessed. These analyses are undertaken for a southern-hemisphere mid-latitude site where a 10-years dataset is available. It is confirmed that clouds reduce TR more than UV, in particular for obscured Sun conditions, low cloud fraction (<60%) and large SZA (>60°). Similarly, local short-time enhancement effects are stronger for TR than for UV, mainly for visible Sun conditions, large cloud fraction and large SZA. Two methods to estimate UVI are developed: (1) from sky imaging cloud cover and sunny conditions, and (2) from TR measurements. Both methods may be used in practical applications, although Method 2 shows overall the best performance, as TR allows considering cloud optical properties. The mean absolute (relative) differences of Method 2 estimations with respect to measured values are 0.17 UVI units (6.7%, for 1 min data) and 0.79 Standard Erythemal Dose (SED) units (3.9%, for daily integrations). Method 1 shows less accurate results but it is still suitable to estimate UVI: mean absolute differences are 0.37 UVI units (15%) and 1.6 SED (8.0%). PMID:24645969

Badosa, Jordi; Calbó, Josep; Mckenzie, Richard; Liley, Ben; González, Josep-Abel; Forgan, Bruce; Long, Charles N

2014-01-01

190

Cloud altitudes of Jupiter estimated by imaging observation using a liquid crystal variable filter in the 650 - 1000 nm spectral range  

Microsoft Academic Search

A large optical depth of clouds obstructs us to observe the movement of the atmosphere under clouds directly. However, we can investigate dynamics of the atmosphere indirectly, if we get information on rugged cloud top. To take Jupiter's images at a number of wavelengths and to obtain the spectra of atmosphere at absorption bands of methane make it possible to

H. Matsuura; Y. Takahashi; H. Fukunishi

2005-01-01

191

Mapping low- and high-density clouds in astrophysical nebulae by imaging forbidden line emission  

NASA Astrophysics Data System (ADS)

Emission line ratios have been essential for determining physical parameters such as gas temperature and density in astrophysical gaseous nebulae. With the advent of panoramic spectroscopic devices, images of regions with emission lines related to these physical parameters can, in principle, also be produced. We show that, with observations from modern instruments, it is possible to transform images taken from density-sensitive forbidden lines into images of emission from high- and low-density clouds by applying a transformation matrix. In order to achieve this, images of the pairs of density-sensitive lines as well as the adjacent continuum have to be observed and combined. We have computed the critical densities for a series of pairs of lines in the infrared, optical, ultraviolet and X-rays bands, and calculated the pair line intensity ratios in the high- and low-density limit using a four- and five-level atom approximation. In order to illustrate the method, we applied it to Gemini Multi-Object Spectrograph (GMOS) Integral Field Unit (GMOS-IFU) data of two galactic nuclei. We conclude that this method provides new information of astrophysical interest, especially for mapping low- and high-density clouds; for this reason, we call it `the ld/hd imaging method'. Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the National Science Foundation on behalf of the Gemini partnership: the National Science Foundation (United States); the Science and Technology Facilities Council (United Kingdom); the National Research Council (Canada), CONICYT (Chile); the Australian Research Council (Australia); Ministério da Ciência e Tecnologia (Brazil) and Secretaria de Ciencia y Tecnologia (Argentina). E-mail: steiner@astro.iag.usp.br

Steiner, J. E.; Menezes, R. B.; Ricci, T. V.; Oliveira, A. S.

2009-06-01

192

A QR Code Based Zero-Watermarking Scheme for Authentication of Medical Images in Teleradiology Cloud  

PubMed Central

Healthcare institutions adapt cloud based archiving of medical images and patient records to share them efficiently. Controlled access to these records and authentication of images must be enforced to mitigate fraudulent activities and medical errors. This paper presents a zero-watermarking scheme implemented in the composite Contourlet Transform (CT)—Singular Value Decomposition (SVD) domain for unambiguous authentication of medical images. Further, a framework is proposed for accessing patient records based on the watermarking scheme. The patient identification details and a link to patient data encoded into a Quick Response (QR) code serves as the watermark. In the proposed scheme, the medical image is not subjected to degradations due to watermarking. Patient authentication and authorized access to patient data are realized on combining a Secret Share with the Master Share constructed from invariant features of the medical image. The Hu's invariant image moments are exploited in creating the Master Share. The proposed system is evaluated with Checkmark software and is found to be robust to both geometric and non geometric attacks. PMID:23970943

Seenivasagam, V.; Velumani, R.

2013-01-01

193

Intelligent technique to search for patterns within images in massive databases  

SciTech Connect

An image retrieval system for JET has been developed. The image database contains the images of the JET high speed visible camera. The system input is a pattern selected inside an image and the output is the group of frames (defined by their discharge numbers and time slices) that show patterns similar to the selected one. This approach is based on morphological pattern recognition and it should be emphasized that the pattern is found independently of its location in the frame. The technique encodes images into characters and, therefore, it transforms the pattern search into a character-matching problem.

Vega, J.; Murari, A.; Pereira, A.; Portas, A.; Castro, P. [JET-EFDA, Culham Science Center, OX14 3DB Abingdon (United Kingdom)

2008-10-15

194

Spatial-temporal change in precipitation patterns based on the cloud model across the Wei River Basin, China  

NASA Astrophysics Data System (ADS)

It is of significant importance to investigate the spatial-temporal change in precipitation patterns due to its great effects on droughts, floods, soil erosion and water resource management. A complete investigation of precipitation structure and its distribution pattern based on daily precipitation covering 1960-2005 at 21 meteorological stations in the Wei River Basin has been performed. In order to comprehensively and objectively describe the changing pattern of precipitation, the cloud model is employed to quantitatively analyse the average, uniformity and stability of precipitation. Results indicate the following: (1) the occurrence of different precipitation durations exhibits a positive exponential curve with the decrease in precipitation durations, and 1-3-day events are the predominant precipitation events which have an increasing trend; (2) precipitation and its non-uniformity is increasingly reducing, while its stability increases initially then decreases; (3) mean precipitation reduces from southeast to northwest, and the precipitation of the Guanzhong Plain has a low uniformity and stability due to its location and increasingly intensifying human activities. The cloud model provides a new idea and quantitative measure for the evaluation of the uniformity and stability of precipitation.

Huang, Shengzhi; Hou, Beibei; Chang, Jianxia; Huang, Qiang; Chen, Yutong

2014-05-01

195

Characterizing Spatial Patterns of Cloud Cover and Fog Inundation in the Northern Channel Islands Using Satellite Datasets and Comparison to Ground Measurements  

NASA Astrophysics Data System (ADS)

Coastal forests in Mediterranean climates are frequently covered by clouds or immersed in fog. Previous studies suggest that clouds strongly modulate forest distributions as well as carbon budgets in these semi-arid environments. Both low level stratocumulus cloud cover and fog can enhance the water status of vegetation along the Californian coast and the Channel Islands by reducing solar insolation, raising relative humidity and supplying water directly to the landscape during otherwise warm and rainless summers. While summertime fog and stratus cover in California's Channel Islands can ameliorate summer drought stress and enhance soil water budgets, they have different spatial patterns. These differing spatial patterns and the resulting shifts in relative ecological importance of fog and stratus are largely unknown. The overall objective of this project was to map spatial distributions of daytime cloud cover frequency for the California Channel Islands, and to predict probabilities of surface cloud (fog) contact and immersion for these islands. Daytime cloud cover maps were generated for the Channel Islands using data from GOES satellite imagery. Cloud frequency maps were compared and found to be in agreement with solar insolation data collected at several sites on Santa Cruz and Santa Rosa islands for the summer of 2005. These cloud frequency maps were then combined with airport cloud height data and topographic data to map estimated weekly and monthly fog inundation. The fog inundation maps were then compared to fog drip data collected at several sites on the two islands. Correlation between fog inundation and fog drip accumulation enabled spatial and temporal extrapolation to understand seasonal and inter-annual variations in cloud cover frequency and fog inundation and drip. Future studies will use these cloud and fog distributions for water balance modeling and studies of plant geography and forest distributions.

Rastogi, B.; Still, C. J.; Fischer, D. T.; Iacobellis, S. F.; Toomey, M. P.; Greer, B.; Baguskas, S. A.; Williams, P.; McEachern, K.

2012-12-01

196

Characterization of image transfer patterns in a regional trauma network.  

PubMed

Trauma Networks are currently founded in Germany to improve patient care of severely injured persons. To assure appropriate patient treatment in a short time, the transfer of radiological image data between the connected hospitals over the internet is an important method. This paper characterizes radiological image transfer patterns in a regional trauma network and analyzes various compression options. Within the "TraumaNetwork NorthWest" in Germany, the web-based platform "MedSix" was developed. MedSix is able to transfer DICOM-data quickly and easily between connected hospitals and can be directly connected to the local PACS. Audit data of the routine system between the 01.01.2012 and the 31.12.2012 were analyzed to identify typical characteristics of radiological image exchanges. Five different compression methods were compared by a simulation. MedSix has been used by 12 hospitals. 87 % of the transfers were uploaded within 15 min. Lossless compression is able to save about 50 % bandwidth. 82 % of the transfers have a data volume of less than 200 MB. Temporary accounts for non-regular users were used regularly. Most transfers were done from small to maximum care hospitals. It is feasible to substitute physical image exchange in a trauma network with electronic exchange of radiological images between the connected hospitals. Even large datasets are transferred within an acceptable time frame. Most transfers occur from small to large hospitals. The possibility of temporary accounts seems to be a key feature for the user acceptance. PMID:25265903

Neuhaus, Philipp; Weber, Thomas; Dugas, Martin; Juhra, Christian; Breil, Bernhard

2014-11-01

197

Imaging Dot Patterns for Measuring Gossamer Space Structures  

NASA Technical Reports Server (NTRS)

A paper describes a photogrammetric method for measuring the changing shape of a gossamer (membrane) structure deployed in outer space. Such a structure is typified by a solar sail comprising a transparent polymeric membrane aluminized on its Sun-facing side and coated black on the opposite side. Unlike some prior photogrammetric methods, this method does not require an artificial light source or the attachment of retroreflectors to the gossamer structure. In a basic version of the method, the membrane contains a fluorescent dye, and the front and back coats are removed in matching patterns of dots. The dye in the dots absorbs some sunlight and fluoresces at a longer wavelength in all directions, thereby enabling acquisition of high-contrast images from almost any viewing angle. The fluorescent dots are observed by one or more electronic camera(s) on the Sun side, the shade side, or both sides. Filters that pass the fluorescent light and suppress most of the solar spectrum are placed in front of the camera(s) to increase the contrast of the dots against the background. The dot image(s) in the camera(s) are digitized, then processed by use of commercially available photogrammetric software.

Dorrington, A. A.; Danehy, P. M.; Jones, T. W.; Pappa, R. S.; Connell, J. W.

2005-01-01

198

Cloud Services Cloud Services  

E-print Network

Cloud Services Cloud Services In 2012 UCD IT Services launched an exciting new set of cloud solutions called CloudEdu, which includes cloud servers, cloud storage, cloud hosting and cloud network. The CloudEdu package includes a consultancy service in design, deployment, management and utilisation

199

Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging lidar  

NASA Astrophysics Data System (ADS)

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data on various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

Love, Steven P.; Davis, Anthony B.; Rohde, Charles A.; Tellier, Larry; Ho, Cheng

2002-09-01

200

Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging LIDAR.  

SciTech Connect

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data oti various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

Love, Steven P.; Davis, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Tellier, L. L. (Larry L.); Ho, Cheng,

2002-01-01

201

Multi-provider Architecture for Cloud Outsourcing of Medical Imaging Repositories.  

PubMed

Over the last few years, the extended usage of medical imaging procedures has raised the medical community attention towards the optimization of their workflows. More recently, the federation of multiple institutions into a seamless distribution network has brought hope of increased quality healthcare services along with more efficient resource management. As a result, medical institutions are constantly looking for the best infrastructure to deploy their imaging archives. In this scenario, public cloud infrastructures arise as major candidates, as they offer elastic storage space, optimal data availability without great requirements of maintenance costs or IT personnel, in a pay-as-you-go model. However, standard methodologies still do not take full advantage of outsourced archives, namely because their integration with other in-house solutions is troublesome. This document proposes a multi-provider architecture for integration of outsourced archives with in-house PACS resources, taking advantage of foreign providers to store medical imaging studies, without disregarding security. It enables the retrieval of images from multiple archives simultaneously, improving performance, data availability and avoiding the vendor-locking problem. Moreover it enables load balancing and cache techniques. PMID:25160163

Godinho, Tiago Marques; Bastião Silva, Luís A; Costa, Carlos; Oliveira, José Luís

2014-01-01

202

A 10-year climatology of Northern Hemisphere tropical cloud plumes and their composite flow patterns  

SciTech Connect

A 10-year cool season climatology of tropical cloud plumes in the Northern Hemisphere was generated by visual inspection of infrared satellite imagery. The sample included 1062 plume events during the months of October to May for the years 1974 to 1984. The results show that the westerly ducts of the tropical eastern Pacific and central Atlantic are preferred regions for tropical cloud plume development. Composite fields of streamfunction and outgoing longwave radiation for eastern Pacific plumes indicate that both low-latitude westerlies in the planetary-scale basic-state flow and the presence of synoptic-scale transients appear to be favorable for plume formation. With a knowledge of these features, some of the interannual and intraannual variability shown in the climatology can be explained. 14 refs., 6 figs.

Iskenderian, H. [State Univ. of New York, Albany, NY (United States)] [State Univ. of New York, Albany, NY (United States)

1995-06-01

203

Pattern Recognition Of Blood Vessel Networks In Ocular Fundus Images  

NASA Astrophysics Data System (ADS)

We propose a computer method of recognizing blood vessel networks in color ocular fundus images which are used in the mass diagnosis of adult diseases such as hypertension and diabetes. A line detection algorithm is applied to extract the blood vessels, and the skeleton patterns of them are made to analyze and describe their structures. The recognition of line segments of arteries and/or veins in the vessel networks consists of three stages. First, a few segments which satisfy a certain constraint are picked up and discriminated as arteries or veins. This is the initial labeling. Then the remaining unknown ones are labeled by utilizing the physical level knowledge. We propose two schemes for this stage : a deterministic labeling and a probabilistic relaxation labeling. Finally the label of each line segment is checked so as to minimize the total number of labeling contradictions. Some experimental results are also presented.

Akita, K.; Kuga, H.

1982-11-01

204

Observation of lake current patterns using satellite images and comparison with results from numerical simulations  

Microsoft Academic Search

Six LANDSAT TM images of Lake Suwa, Japan, were processed to extract current patterns. The lake was almost completely covered with Aoko (phytoplankton bloom) in three summer images. But two spring images, which were after rainfall, showed dispersion patterns of suspended particles from a river. The directions of dispersion were the same as the local wind at the mouth of

T. Matsunaga; Y. Okubo; Y. Inouchi

1993-01-01

205

High-resolution imaging of compact high-velocity clouds (II)  

E-print Network

We have imaged five compact high-velocity clouds in HI with arcmin angular- and km/s spectral-resolution using the WSRT. Supplementary total-power data, which is fully sensitive to both the cool and warm components of HI, is available for comparison for all the sources, albeit with angular resolutions that vary from 3' to 36'. The fractional HI flux in compact CNM components varies from 4% to 16% in our sample. All objects have at least one local peak in the CNM column which exceeds about 10^19 cm^-2 when observed with arcmin resolution. It is plausible that a peak column density of 1-2x10^19 cm^-2 is a prerequisite for the long-term survival of these sources. One object in our sample, CHVC120-20-443 (Davies' cloud), lies in close projected proximity to the disk of M31. This object is characterized by exceptionally broad linewidths in its CNM concentrations (more than 5 times greater than the median value). These CNM concentrations lie in an arc on the edge of the source facing the M31 disk, while the diffuse HI component of this source has a position offset in the direction of the disk. All of these attributes suggest that CHVC120-20-443 is in a different evolutionary state than most of the other CHVCs which have been studied. Similarly broad CNM linewidths have only been detected in one other object, CHVC111-07-466, which also lies in the Local Group barycenter direction and has the most extreme radial velocity known. A distinct possibility for Davies' cloud seems to be physical interaction of some type with M31. The most likely form of this interaction might be the ram-pressure or tidal- stripping by either one of M31's visible dwarf companions, M32 or NGC205, or else by a dark companion with an associated HI condensation.

V. de Heij; R. Braun; W. B. Burton

2002-06-19

206

Near-IR Imaging Polarimetry toward a Bright-Rimmed Cloud: Magnetic Field in SFO 74  

E-print Network

We have made near-infrared (JHKs) imaging polarimetry of a bright-rimmed cloud (SFO 74). The polarization vector maps clearly show that the magnetic field in the layer just behind the bright rim is running along the rim, quite different from its ambient magnetic field. The direction of the magnetic field just behind the tip rim is almost perpendicular to that of the incident UV radiation, and the magnetic field configuration appears to be symmetric as a whole with respect to the cloud symmetry axis. We estimated the column and number densities in the two regions (just inside and far inside the tip rim), and then derived the magnetic field strength, applying the Chandrasekhar-Fermi method. The estimated magnetic field strength just inside the tip rim, ~90 uG, is stronger than that far inside, ~30 uG. This suggests that the magnetic field strength just inside the tip rim is enhanced by the UV radiation induced shock. The shock increases the density within the top layer around the tip, and thus increases the str...

Kusune, Takayoshi; Miao, Jingqi; Tamura, Motohide; Sato, Yaeko; Kwon, Jungmi; Watanabe, Makoto; Nishiyama, Shogo; Nagayama, Takahiro; Sato, Shuji

2014-01-01

207

Complex Clouds  

... the north of Enderbyland, East Antarctica. The image at left was created by overlying a natural-color view from MISR's ... causes the cloud-tops to be brightly outlined by the sun behind them, and enhances the shadows cast by clouds with significant vertical ...

2013-04-16

208

Water vapor motion signal extraction from FY-2E longwave infrared window images for cloud-free regions: The temporal difference technique  

NASA Astrophysics Data System (ADS)

The aim of this study is to calculate the low-level atmospheric motion vectors (AMVs) in clear areas with FY-2E IR2 window (11.59-12.79 ?m) channel imagery, where the traditional cloud motion wind technique fails. A new tracer selection procedure, which we call the temporal difference technique, is demonstrated in this paper. This technique makes it possible to infer low-level wind by tracking features in the moisture pattern that appear as brightness temperature ( T B) differences between consecutive sequences of 30-min-interval FY-2E IR2 images over cloud-free regions. The T B difference corresponding to a 10% change in water vapor density is computed with the Moderate Resolution Atmospheric Transmission (MODTRAN4) radiative transfer model. The total contribution from each of the 10 layers is analyzed under four typical atmospheric conditions: tropical, midlatitude summer, U.S. standard, and midlatitude winter. The peak level of the water vapor weighting function for the four typical atmospheres is assigned as a specific height to the T B "wind". This technique is valid over cloud-free ocean areas. The proposed algorithm exhibits encouraging statistical results in terms of vector difference (VD), speed bias (BIAS), mean vector difference (MVD), standard deviation (SD), and root-mean-square error (RMSE), when compared with the wind field of NCEP reanalysis data and rawinsonde observations.

Yang, Lu; Wang, Zhenhui; Chu, Yanli; Zhao, Hang; Tang, Min

2014-11-01

209

Application of Cloude's target decomposition theorem to polarimetric imaging radar data  

NASA Technical Reports Server (NTRS)

In this paper we applied Cloude's decomposition to imaging radar polarimetry. We show in detail how the decomposition results can guide the interpretation of scattering from vegetated areas. For multifrequency polarimetric radar measurements of a clear-cut area, the decomposition leads us to conclude that the vegetation is probably thin compared to even the C-band radar wavelength of 6 cm. For a frosted area, we notice an increased amount of even number of reflection scattering at P-band and L-band, probably the result of penetration through the coniferous canopy resulting in trunk-ground double reflection scattering. However, the scattering for the forested area is still dominated by scattering from randomly oriented cylinders. It is found that these cylinders are thicker than in the case of clear-cut areas, leading us to conclude that scattering from the branches probably dominates in this case.

Vanzyl, Jakob J.

1993-01-01

210

Remote sensing of cloud, aerosol and water vapor properties from the Moderate Resolution Imaging Spectrometer (MODIS)  

NASA Technical Reports Server (NTRS)

The Moderate Resolution Imaging Spectrometer (MODIS) is an Earth-viewing sensor being developed as a facility instrument for the Earth Observing System (EOS) to be launched in the late 1990s. MODIS consists of two separate instruments that scan a swath width sufficient to provide nearly complete global coverage every two days from a polar-orbiting, Sun-synchronous, platform at an altitude of 705 km. Of primary interest for studies of atmospheric physics is the MODIS-N (nadir) instrument which will provide images in 36 spectral bands between 0.415 and 14.235 micrometers with spatial resoulutions of 250 m (2 bands), 500 m (5 bands) and 1000 m (29 bands). These bands have been carefully selected to enable advanced studies of land, ocean and atmosperhic processes. The intent of this lecture is to describe the current status of MODIS-N and its companion instrument MODIS-T (tilt), a tiltable cross-track scanning radiometer with 32 uniformly spaced channels between 0.410 and 0.875 micrometers, and to describe the physical principles behind the development of MODIS for the remote sensing of atmospheric properties. Primary emphasis will be placed on the main atmospheric applications of determining the optical, microphysical and physical properties of clouds and aerosol particles form spectral-reflection and thermal-emission measurements. In addition to cloud and aerosol properties, MODIS-N will be utilized for the determination of the total precipitable water vapor over land and atmospheric stability. The physical principles behind the determination of each of these atmospheric products will be described herein.

King, M. D.

1992-01-01

211

Types of Clouds  

NSDL National Science Digital Library

This is a basic lesson on clouds. Very nice photos of cumulus and cumulonimbus clouds are presented on the page as well as a description of all major cloud types and their associated weather. Two activities are presented. One invites the learner to create a cloud, while the other involves creating a collage of cloud images along with information about the weather associated with each cloud type.

Friend, Duane

212

Saturn's cloud structure and temporal evolution from ten years of Hubble Space Telescope images (1994–2003)  

Microsoft Academic Search

We present a study of the vertical structure of clouds and hazes in the upper atmosphere of Saturn's Southern Hemisphere during 1994–2003, about one third of a Saturn year, based on Hubble Space Telescope images. The photometrically calibrated WFPC2 images cover the spectral region between the near-UV (218–255 nm) and the near-IR (953–1042 nm), including the 890 nm methane band.

S. Pérez-Hoyos; A. Sánchez-Lavega; R. G. French; J. F. Rojas

2005-01-01

213

PSC Meteorology Program Cloud Boutique  

NSDL National Science Digital Library

Plymouth State College (PSC) provides the PSC Meteorology Program Cloud Boutique Website to "provide explanations of and access to detailed pictures of some basic cloud forms." Spectacular images and brief descriptions of high clouds (cirrus, cirrocumulus, and cirrostratus), middle clouds (altocumulus and altostratus), low clouds (cumulus, stratocumulus, stratus, and fog), multi-layer clouds (nimbostratus and cumulonimbus), and orographic clouds (lenticular and cap), among others are included. The site is an excellent general cloud reference.

214

Automated method for the removal of unwanted nonperiodic patterns from forensic images  

NASA Astrophysics Data System (ADS)

The aim of this work is the removal of distracting background patterns from forensic evidence so that the evidence is rendered more visible. An example is the image of a finger print on a non-periodic background. The method involves registering the image with a control image of the background pattern that we seek to remove. A statistical comparison of the registered images identifies the latent mark.

Capel, David; Zisserman, Andrew; Bramble, Simon K.; Compton, David

1999-02-01

215

Characterizing growth patterns in longitudinal MRI using image contrast  

NASA Astrophysics Data System (ADS)

Understanding the growth patterns of the early brain is crucial to the study of neuro-development. In the early stages of brain growth, a rapid sequence of biophysical and chemical processes take place. A crucial component of these processes, known as myelination, consists of the formation of a myelin sheath around a nerve fiber, enabling the effective transmission of neural impulses. As the brain undergoes myelination, there is a subsequent change in the contrast between gray matter and white matter as observed in MR scans. In this work, gray-white matter contrast is proposed as an effective measure of appearance which is relatively invariant to location, scanner type, and scanning conditions. To validate this, contrast is computed over various cortical regions for an adult human phantom. MR (Magnetic Resonance) images of the phantom were repeatedly generated using different scanners, and at different locations. Contrast displays less variability over changing conditions of scan compared to intensity-based measures, demonstrating that it is less dependent than intensity on external factors. Additionally, contrast is used to analyze longitudinal MR scans of the early brain, belonging to healthy controls and Down's Syndrome (DS) patients. Kernel regression is used to model subject-specific trajectories of contrast changing with time. Trajectories of contrast changing with time, as well as time-based biomarkers extracted from contrast modeling, show large differences between groups. The preliminary applications of contrast based analysis indicate its future potential to reveal new information not covered by conventional volumetric or deformation-based analysis, particularly for distinguishing between normal and abnormal growth patterns.

Vardhan, Avantika; Prastawa, Marcel; Vachet, Clement; Piven, Joseph; Gerig, Guido

2014-03-01

216

Characterizing growth patterns in longitudinal MRI using image contrast  

PubMed Central

Understanding the growth patterns of the early brain is crucial to the study of neuro-development. In the early stages of brain growth, a rapid sequence of biophysical and chemical processes take place. A crucial component of these processes, known as myelination, consists of the formation of a myelin sheath around a nerve fiber, enabling the effective transmission of neural impulses. As the brain undergoes myelination, there is a subsequent change in the contrast between gray matter and white matter as observed in MR scans. In this work, gray-white matter contrast is proposed as an effective measure of appearance which is relatively invariant to location, scanner type, and scanning conditions. To validate this, contrast is computed over various cortical regions for an adult human phantom. MR (Magnetic Resonance) images of the phantom were repeatedly generated using different scanners, and at different locations. Contrast displays less variability over changing conditions of scan compared to intensity-based measures, demonstrating that it is less dependent than intensity on external factors. Additionally, contrast is used to analyze longitudinal MR scans of the early brain, belonging to healthy controls and Down’s Syndrome (DS) patients. Kernel regression is used to model subject-specific trajectories of contrast changing with time. Trajectories of contrast changing with time, as well as time-based biomarkers extracted from contrast modeling, show large differences between groups. The preliminary applications of contrast based analysis indicate its future potential to reveal new information not covered by conventional volumetric or deformation-based analysis, particularly for distinguishing between normal and abnormal growth patterns. PMID:25309699

Vardhan, Avantika; Prastawa, Marcel; Vachet, Clement; Piven, Joseph; Gerig, Guido

2014-01-01

217

Thermal neutron image intensifier tube provides brightly visible radiographic pattern  

NASA Technical Reports Server (NTRS)

Vacuum-type neutron image intensifier tube improves image detection in thermal neutron radiographic inspection. This system converts images to an electron image, and with electron acceleration and demagnification between the input target and output screen, produces a bright image viewed through a closed circuit television system.

Berger, H.; Kraska, I.; Niklas, W.; Schmidt, A.

1967-01-01

218

Image-based correlation of Laser Scanning point cloud time series for landslide monitoring  

NASA Astrophysics Data System (ADS)

Very high resolution monitoring of landslide kinematics is an important aspect for a physical understanding of the failure mechanisms and for quantifying the associated hazard. In the last decade, the potential of Terrestrial Laser Scanning (TLS) to monitor slow-moving landslides has been largely demonstrated but accurate processing methods are still needed to extract useful information available in point cloud time series. This work presents an approach to measure the 3D deformation and displacement patterns from repeated TLS surveys. The method is based on the simplification of a 3D matching problem in a 2D matching problem by using a 2D statistical normalized cross-correlation function. The computed displacement amplitudes are compared to displacements (1) calculated with the classical approach of Iterative Closest Point and (2) measured from repeated dGPS observations. The performance of the method is tested on a 3 years dataset acquired at the Super-Sauze landslide (South French Alps). The observed landslide displacements are heterogeneous in time and space. Within the landslide, sub-areas presenting different deformation patterns (extension, compression) are detected by a strain analysis. It is demonstrated that pore water pressure changes within the landslide is the main controlling factor of the kinematics.

Travelletti, Julien; Malet, Jean-Philippe; Delacourt, Christophe

2014-10-01

219

Multispectral Image Recognition Research Based on Biomimetic Pattern Recognition  

Microsoft Academic Search

Studies on learning problems from geometry perspective have attracted an ever increasing attention in machine learning, leaded by biomimetic pattern recognition on information geometry. Biomimetic pattern recognition is a new model of pattern recognition based on ldquomatter cognitionrdquo instead of ldquomatter classificationrdquo. This new model is much closer to the function of human being, than traditional statistical pattern recognition using

Wenming Cao; Hao Feng

2009-01-01

220

Cloud model evaluation using radiometric measurements from the airborne multiangle imaging spectroradiometer (AirMISR)  

Microsoft Academic Search

Detailed information on cloud properties is needed to rigorously test retrieval algorithms for satellite and ground-based remote sensors. The inherent complexity of clouds makes this information difficult to obtain from observations alone and cloud resolving models (CRMs) are often used to generate synthetic datasets that can be used as proxies for real data. We test the ability of a CRM

Mikhail Ovtchinnikov; Roger T. Marchand

2007-01-01

221

Resolution analysis in computational imaging with patterned illumination and single-pixel detection  

NASA Astrophysics Data System (ADS)

In computational imaging by pattern projection a sequence of microstructured light patterns codified onto a programmable spatial light modulator is used to sample an object. The patterns are used as generalized measurement modes where the object information is expressed. Our paper makes two specific contributions within the field of single-pixel imaging through patterned illumination. First, we perform an analysis of the optical resolution of the computational image. This resolution is shown not to be limited at all by the optical quality of the collection optics. This result is proved by using a low NA microscope objective for imaging at a CCD camera. Spatial frequencies that are not transmitted through this low quality optics are demonstrated to be present in the retrieved image through patterned illumination. Second, we experimentally demonstrate the capability of our technique to properly recover an image even when an optical diffuser is located in between the sample and the single-pixel detector.

Rodriguez, A. D.; Clemente, P.; Irles, E.; Tajahuerce, E.; Lancis, J.

2014-08-01

222

Local binary patterns for stromal area removal in histology images  

NASA Astrophysics Data System (ADS)

Nuclei counting in epithelial cells is an indication for tumor proliferation rate which is useful to rank tumors and select an appropriate treatment schedule for the patient. However, due to the high interand intra- observer variability in nuclei counting, pathologists seek a deterministic proliferation rate estimate. Histology tissue contains epithelial and stromal cells. However, nuclei counting is clinically restricted to epithelial cells because stromal cells do not become cancerous themselves since they remain genetically normal. Counting nuclei existing within the stromal tissue is one of the major causes of the proliferation rate non-deterministic estimation. Digitally removing stromal tissue will eliminate a major cause in pathologist counting variability and bring the clinical pathologist a major step closer toward a deterministic proliferation rate estimation. To that end, we propose a computer aided diagnosis (CAD) system for eliminating stromal cells from digital histology images based on the local binary patterns, entropy measurement, and statistical analysis. We validate our CAD system on a set of fifty Ki-67-stained histology images. Ki-67-stained histology images are among the clinically approved methods for proliferation rate estimation. To test our CAD system, we prove that the manual proliferation rate estimation performed by the expert pathologist does not change before and after stromal removal. Thus, stromal removal does not affect the expert pathologist estimation clinical decision. Hence, the successful elimination of the stromal area highly reduces the false positive nuclei which are the major confusing cause for the less experienced pathologists and thus accounts for the non-determinism in the proliferation rate estimation. Our experimental setting shows statistical insignificance (paired student t-test shows ? = 0.74) in the manual nuclei counting before and after our automated stromal removal. This means that the clinical decision of the expert pathologist is not affected by our CAD system which is what we want to prove. However, the usage of our CAD system substantially account for the reduced inter- and intra- proliferation rate estimation variability and especially for less-experienced pathologists.

Alomari, Raja S.; Ghosh, Subarna; Chaudhary, Vipin; Al-Kadi, Omar

2012-03-01

223

Daytime variation of absorbing aerosols above stratocumulus clouds and their radiative impacts from the Spinning Enhanced Visible and Infrared Imager (SEVIRI)  

NASA Astrophysics Data System (ADS)

Due to the high temporal variation of atmospheric aerosols, large uncertainties remain in quantifying the radiative effects of absorbing aerosols above clouds. This study examines the radiative effects of smoke aerosols above stratocumulus clouds from spectral, spatial, and temporal techniques using the Spinning Enhanced Visible and Infrared Imager (SEVIRI) data. The high temporal (15-minute) resolution of SEVIRI allows for a detailed investigation of daytime variation of smoke above clouds. This new technique is validated with the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations. Spectral signatures of above-cloud smoke are assessed in terms of cloud optical depth (COD), aerosol index (AI), and aerosol optical depth (AOD) using the Moderate Resolution Imaging Spectroradiometer (MODIS), the Ozone Monitoring Instrument (OMI), and other data sets. A four stream radiative transfer model is used to assess the radiative impacts.

Christopher, S. A.; Chang, I.

2013-12-01

224

ENVI Services Engine: Earth and Planetary Image Processing for the Cloud  

NASA Astrophysics Data System (ADS)

The geospatial imagery analysis and exploitation community has a growing need for online analytic capabilities. Work previously done on desktop workstations must migrate to a web-accessible environment to mitigate growing data volumetrics, bandwidth usage, and end user requirements. Web based applications (or 'apps') are intended to apply analytic methods, procedures, and routines to image datasets stored within centralized server repositories. Exelis Visual information Solutions (VIS) developed an enterprise-enabled processing engine that provides remote users access to the power of ENVI image analysis and IDL applications from a web or mobile client interface. The working name for this capability is the ENVI and IDL Services Engine (ESE). This engine now enables the remote user to gain access to the same compiled ENVI and IDL functions and procedures that remote sensing scientists have utilized for decades at the desktop level. ESE operates in a RESTful state, listening for http calls to arrive that initiate a data processing operation once those messages are registered. ESE is middleware agnostic, meaning users can implement this capability using their current enterprise architecture such as ArcGIS Server or GeoServer. Flexibility and openness in middleware components is achieved through the use of OGC standards for message and data transfer. ESE represents bringing long term earth science monitoring analysis capabilities to the cloud, harnessing existing ENVI and IDL tools and deploying them to the enterprise, and improving access to earth and planetary science data.

O'Connor, A. S.; Lausten, K.; Heightley, K.; Harris, T.

2012-12-01

225

Infrared Imaging of the Large Magellanic Cloud Star-forming Region Henize 206  

NASA Astrophysics Data System (ADS)

Henize 206 is a region of star formation in the Large Magellanic Cloud of the approximate scale of the Orion belt and sword. Our Spitzer Space Telescope infrared images and Cerro Tololo Inter-American Observatory (CTIO) optical images show that the region is experiencing very energetic star formation. The radiation from young stars has excited strong polycyclic aromatic hydrocarbon (PAH) emission throughout Henize 206, except on the side of the nebula with the prominent young supernova remnant. As is also seen in early Spitzer observations of M81, star formation rates calculated from H? for Henize 206 may miss the deeply embedded young stars, compared with star formation rates calculated from far infrared emission. For one of the highest surface brightness regions of Henize 206, we obtained snapshot exposures with the Thermal-Region Camera Spectrograph on Gemini South to explore the complex structure. A few percent of the total flux from this brightest region in Henize 206 emanates from infrared peaks of subparsec scale.

Gorjian, V.; Werner, M. W.; Mould, J. R.; Gordon, K. D.; Muzzerole, J.; Morrison, J.; Surace, J. M.; Rebull, L. M.; Hurt, R. L.; Smith, R. C.; Points, S. D.; Aguilera, C.; De Buizer, J. M.; Packham, C.

2004-09-01

226

Design of an in-line, digital holographic imaging system for airborne measurement of clouds.  

PubMed

We discuss the design and performance of an airborne (underwing) in-line digital holographic imaging system developed for characterizing atmospheric cloud water droplets and ice particles in situ. The airborne environment constrained the design space to the simple optical layout that in-line non-beam-splitting holography affords. The desired measurement required the largest possible sample volume in which the smallest desired particle size (?5 ?m) could still be resolved, and consequently the magnification requirement was driven by the pixel size of the camera and this particle size. The resulting design was a seven-element, double-telecentric, high-precision optical imaging system used to relay and magnify a hologram onto a CCD surface. The system was designed to preserve performance and high resolution over a wide temperature range. Details of the optical design and construction are given. Experimental results demonstrate that the system is capable of recording holograms that can be reconstructed with resolution of better than 6.5 ?m within a 15 cm(3) sample volume. PMID:21460907

Spuler, Scott M; Fugal, Jacob

2011-04-01

227

Visual simulation of clouds  

Microsoft Academic Search

Clouds present serious problems to standard computer image generation techniques because clouds do not have well-defined surfaces and boundaries. In addition, clouds contain varying degrees of translucence, and their amorphous structure can change with time. Although several approaches to cloud simulation have produced impressive results, they have relied on complex mathematical models which produce high computation costs for a single

Geoffrey Y. Gardner

1985-01-01

228

Learning local binary patterns for gender classification on real-world face images Caifeng Shan  

E-print Network

for marketing, etc. Human faces provide important visual information for gender perception. GenderLearning local binary patterns for gender classification on real-world face images Caifeng Shan May 2011 Keywords: Gender classification Local binary patterns Face image analysis a b s t r a c

Kim, Tae-Kyun

229

Wide-Area Imaging of Ultrasonic Lamb Wave Fields by Electronic Speckle Pattern Interferometry  

E-print Network

. K.-J. Pohl et a1113' described a pulsed holographic system for imaging laser generated RayleighWide-Area Imaging of Ultrasonic Lamb Wave Fields by Electronic Speckle Pattern Interferometry Grant vibration data collected via electronic speckle pattern interferometry used in combination with laser

Mast, T. Douglas

230

Workshop on Standards for Image Pattern Recognition. Computer Seience & Technology Series.  

ERIC Educational Resources Information Center

Automatic image pattern recognition techniques have been successfully applied to improving productivity and quality in both manufacturing and service applications. Automatic Image Pattern Recognition Algorithms are often developed and tested using unique data bases for each specific application. Quantitative comparison of different approaches and…

Evans, John M. , Ed.; And Others

231

Image segmentation of UV pattern for automatic paper-money inspection  

Microsoft Academic Search

We propose an image segmentation method for automatic paper-money inspection system. The UV (ultra violet) patterns embedded in the paper money should be segmented to determine whether the money is genuine or not. We acquired the image by directional lighting system using UV LEDs. In order to segment the pattern from the background, we apply the Gaussian mixture model to

Keon-Ho Lee; Tae-Hyoung Park

2010-01-01

232

Efficient strategies for many-task frequent pattern mining in cloud computing environments  

Microsoft Academic Search

The goal of data mining is to discover the hidden useful information from large databases. Mining frequent patterns from transaction databases is an important problem in data mining field. As the size of database increases, the computation time and the required memory increase severely. Parallel and distributed computing techniques have attracted extensive attentions on the ability to manage and compute

Kawuu W. Lin; Yu-Chin Luo

2010-01-01

233

Suppression of moiré patterns in scanned halftone images by double scans with grid movements  

Microsoft Academic Search

Moir6 patterns often appear in images obtained from scanning printings on magazines or newspapers. The patterns do not exist in the original printings but come from alias sampling of the screened halftone pictures. A new method of scanning is proposed to suppress the moir6 patterns. First, the Fourier analyses of both screening and scanning are presented, from which the new

James Ching-yu Yang; Wen-hsiang Tsai

1997-01-01

234

Document image segmentation and quality improvement by moireH pattern analysisq  

Microsoft Academic Search

MoireH patterns are distortions on the results of scanning printed documents. However, the patterns can be utilized in document image segmentation and quality improvement. The moireH phenomenon comes from sampling periodical structures in images, such as halftone screens, color components, and text galleys which often appear in printed magazines and newspapers. The generated moireH patterns appear in the scanning result

James Ching-Yu Yang; Wen-Hsiang Tsai

235

Experience With The SMPTE Test Pattern In Quality Control Of Magnetic Resonance Images  

NASA Astrophysics Data System (ADS)

The SMPTE test pattern has proven to be an effective tool for calibrating and monitoring the image display devices of a magnetic resonance (MR) imaging system. Linearity and size adjustments of video displays are particulary important because of the proximity of magnetic fields. The 5% and 95% intensity levels of the test pattern are extremely useful for adjusting the grayscale of both video displays and multiformat hardcopy devices. An appropriate sequence of operations for adjusting and monitoring image display devices is recommended.

Bronskill, Michael J.

1984-08-01

236

Dependence of subjective image focus on the magnitude and pattern of high order aberrations.  

PubMed

The image formed by the eye's optics is inherently blurred by aberrations specific to the individual's eyes. We examined to what extent judgments of perceived focus depend on the total magnitude as opposed to the specific pattern of blur introduced by the eye's high order aberrations (HOA). An Adaptive Optics system was used to simultaneously correct each subject's wave aberrations and display natural images blurred by simulated aberrations. To isolate the effects of blur magnitude, images were blurred by pure symmetric defocus, and subjects judged the level of the defocus that subjectively appeared best focused (i.e., neither too blurred nor too sharp). These settings were strongly correlated with the native blur magnitude. To isolate the effect of the HOA pattern, retinal image blur was instead maintained at a constant blur (Strehl Ratio) equal to each subject's natural blur, and subjects judged the best-focused image from pairs of images blurred by different patterns of HOA, one selected from 100 patterns, the other blurred by a reference pattern which included the subject's natural HOA, rotated HOA, or nine other HOA patterns. The percentage of images judged as best focused was not systematically higher when filtered with the subject's own HOA pattern. However, all subjects preferred their own HOA to the rotated version significantly more often (57% versus 45% on average across subjects). The representation of subjective image focus thus appears to be driven primarily by the overall amount of blur and only weakly by HOA blur orientation. PMID:22872776

Sawides, Lucie; Dorronsoro, Carlos; de Gracia, Pablo; Vinas, Maria; Webster, Michael; Marcos, Susana

2012-01-01

237

Atmospheric moisture and cloud structure determined from SSM/I and global gridpoint analyses. [Special Sensor Microwave Imager  

NASA Technical Reports Server (NTRS)

Data from the Special Sensor Microwave Imager/I on the DMSP satellite are used to study atmospheric moisture and cloud structure. Column-integrated water vapor and total liquid water retrievals are obtained using an algorithm based on a radiative model for brightness temperature (Wentz, 1983). The results from analyzing microwave and IR measurements are combined with independent global gridpoint analyses to study the distribution and structure of atmospheric moisture over oceanic regions.

Robertson, Franklin R.; Huang, Huo-Jin

1989-01-01

238

Improving Cloud Detection in Satellite Images of Coral Reef Environments Using Space Shuttle Photographs and High-Definition Television  

NASA Technical Reports Server (NTRS)

Coral reefs worldwide are suffering from severe and rapid degradation (Bryant et A, 1998; Hoegh-Guldberg, 1999). Quick, consistent, large-scale assessment is required to assess and monitor their status (e.g., USDOC/NOAA NESDIS et al., 1999). On-going systematic collection of high resolution digital satellite data will exhaustively complement the relatively small number of SPOT, Landsat 4-5, and IRS scenes acquired for coral reefs the last 20 years. The workhorse for current image acquisition is the Landsat 7 ETM+ Long Term Acquisition Plan (Gasch et al. 2000). Coral reefs are encountered in tropical areas and cloud contamination in satellite images is frequently a problem (Benner and Curry 1998), despite new automated techniques of cloud cover avoidance (Gasch and Campana 2000). Fusion of multidate acquisitions is a classical solution to solve the cloud problems. Though elegant, this solution is costly since multiple images must be purchased for one location; the cost may be prohibitive for institutions in developing countries. There are other difficulties associated with fusing multidate images as well. For example, water quality or surface state can significantly change through time in coral reef areas making the bathymetric processing of a mosaiced image strenuous. Therefore, another strategy must be selected to detect clouds and improve coral reefs mapping. Other supplemental data could be helpful and cost-effective for distinguishing clouds and generating the best possible reef maps in the shortest amount of time. Photographs taken from the 1960s to the present from the Space Shuttle and other human-occupied spacecraft are one under-used source of alternative multitemporal data (Lulla et al. 1996). Nearly 400,000 photographs have been acquired during this period, an estimated 28,000 of these taken to date are of potential value for reef remote sensing (Robinson et al. 2000a). The photographic images can be digitized into three bands (red, green and blue) and processed for various applications (e.g., Benner and Curry 1998, Nedeltchev 1999, Glasser and Lulla 2000, Robinson et al. 2000c, Webb et al, in press).

Andrefeouet, Serge; Robinson, Julie

2000-01-01

239

Adaptive Optics imaging of small cloud features on Neptune: zonal wind variability and detections of oscillations in longitude  

NASA Astrophysics Data System (ADS)

We present the results of an imaging experiment designed to track the motions of clouds in the upper atmosphere of Neptune. Images were taken in H band (1.4-1.8 microns) with a resolution of .06 arcseconds using the NIRSPEC/AO system on the W. M. Keck II telescope August 20 2001 UT. This dataset is unique in that it is densely sampled in time: 56 images were taken during 4 hours, and the time interval between images ranged from 1 to 32 minutes. The positions as a function of time were determined for 51 cloud features at southern midlatitudes (15-50 degrees South.) In this region, cloud features are visually organized into bands of clouds that almost follow lines of constant latitude. The two major findings of this analysis are: 1. The drift rates of clouds (as determined from the linear fit of longitude versus time curves) are highly variable for a given latitude band. Rotation periods range over several hours per cloud band, yielding relative velocities that are in some cases supersonic. 2. Graphs of longitude versus time are not strictly linear but rather show an oscillation in longitude. We have subtracted the linear drift rate and made empirical fits to the residuals of 12 features which have the longest time baselines of observations. Amplitudes of oscillations are 2-4 degrees of longitude, and periods are comparable to the 4 hour observation time. This is the first detection of small oscillations in the atmosphere of Neptune. Sromovsky, Limaye and Frye (1993) measured oscillations of much greater amplitudes and periods in the Great Dark Spot (GDS) and in the Second Dark Spot (DS2) of Neptune using Voyager data. This research was supported in part by the STC Program of the National Science Foundation under Agreement No. AST-9876783, and in part under the auspices of the US Department of Energy at Lawrence Livermore National Laboratory, Univ. of Calif. under contract No. W-7405-Eng-48. Data presented herein were obtained at the W.M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W.M. Keck Foundation.

Martin, S. C.; de Pater, I.; Gibbard, S. G.; Marcus, P.; Roe, H. G.; Macintosh, B. A.; Max, C. E.

2004-11-01

240

Imaging Use and Cryptorchidism: Determinants of Practice Patterns  

PubMed Central

Purpose We determined the rate of diagnostic imaging use for the preoperative evaluation of boys with cryptorchidism and the factors that influence referring providers to obtain imaging. Materials and Methods We conducted a national cross-sectional survey of pediatricians randomly sampled from the American Medical Association Physician Masterfile. The primary outcome was whether the respondent obtained imaging at the initial evaluation of boys with cryptorchidism. Participants were queried regarding practice location and type, length of time in practice, frequency of reading academic journals and the accessibility of surgical sub-specialists. For those who ordered imaging, respondents were asked how frequently they ordered imaging, and were asked to select patient factors and professional beliefs that influenced their decision to obtain imaging. Factors associated with imaging use were identified using multivariate logistic regression. Results Of the pediatricians who acknowledged contact by surveyors 47% completed the survey and 34% of respondents reported always or usually ordering imaging. Of those who obtained imaging 96.4% used ultrasound. Pediatricians in practice fewer than 20 years (OR 3.43, 95% CI 1.92–6.16) and those in nonacademic practices (OR 3.00, 95% CI 1.34 – 6.71) were more likely to order imaging. Pediatricians obtained imaging because of beliefs that imaging reliably identifies a nonpalpable testis, reassures the family and assists the surgeon with operative planning. Conclusions Ultrasound is heavily used by pediatricians for the preoperative evaluation of cryptorchidism, especially when the testis is nonpalpable. Given the poor diagnostic performance of ultrasound in this setting, we recommend developing strategies to reduce imaging use in cryptorchidism. PMID:21421239

Tasian, Gregory E.; Yiee, Jenny H.; Copp, Hillary L.

2014-01-01

241

Investigation of the complex dynamics and structure of the 2010 Eyjafjallajökull volcanic ash cloud using multispectral images and numerical simulations  

NASA Astrophysics Data System (ADS)

investigated the structure and evolution of the 2010 Eyjafjallajökull volcanic cloud and its dispersal over Iceland and Europe integrating satellite multispectral images and numerical simulations. Data acquired by Medium Resolution Imaging Spectrometer (MERIS) and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) have been analyzed to quantify the cloud extent and composition. The VOL-CALPUFF dispersal code was applied to reconstruct the transient and 3-D evolution of the cloud. Source parameters estimated on the base of available a posteriori volcanological data sets have been used. Quantitative comparisons between satellite retrievals and modeling results were performed for two selected instants of time during the first and third eruptive phases on a regional scale. Sensitivity of the model to initial volcanological conditions has been analyzed at continental scale. Several complex non intuitive features of cloud dynamics have been highlighted and strengths and limitations of the adopted methods identified. The main findings are: the level of quantitative agreement between satellite observations and numerical results depends on ash cloud composition (particle sizes and concentration) with better agreement for smaller particles and higher concentrations; the agreement between observations and modeling outcomes also depends on the temporal stability of volcanological conditions and the complexity of the meteorological wind field; the irregular dispersion of ash, as reconstructed from satellite data and numerical modeling, can be well explained by the different response of particle sizes to strong vertical wind-shear, and by resuspension processes acting at ground level; eruptive source conditions are the main source of uncertainty in modeling, especially during an ongoing crisis and at long-range scales.

Spinetti, C.; Barsotti, S.; Neri, A.; Buongiorno, M. F.; Doumaz, F.; Nannipieri, L.

2013-05-01

242

Cortical Vascular Blood Flow Pattern By Laser Speckle Imaging  

Microsoft Academic Search

The cortical vascular blood flow pattern is associated with the functional response in cerebral cortex. The pattern of the vascular blood flow can be used to study the spatiotemporal activities of the somatosensory center and the diagnosis of the focal stroke or ischemia. In this present study, temporal laser speckle analysis is used to obtain the cortical blood flow information.

Nan Li; Shanbao Tong; Deliang Ye; Hyunchool Shin; Nitish V. Thakor

2005-01-01

243

Information embedding to a real object by projecting a checkered-pattern carrier-screen image  

NASA Astrophysics Data System (ADS)

We propose an information embedding technique to a real object by projecting a checkered-pattern carrier-screen image as an illumination. The carrier-screen image is an information hiding technique, which can decode a secret image physically by superimposing a periodic pattern. As a kind of carrier-screen images, we have developed the checkered-pattern carrier-screen images, which can be physically decoded by superimposing a sheet of checkered pattern. The secret information is also visualized by image sampling with certain interval. As an example of decoding by image sampling, we proposed a decoding method with a compact digital camera. The encoded carrier-screen image has an almost uniform pattern, because modulating a checkered pattern generates it. It is also easy to display on a liquid-crystal display, because it is represented on a square pixel structure. Experimental optical embedding and decoding with a digital camera results show effectiveness of the proposed system. Since the embedded information can be decoded by using an ordinary digital camera, our system expected to use not only steganographic purpose also prevention techniques on taking photos.

Shogenji, Rui

2014-09-01

244

Remote sensing of cloud droplet size distributions in DC3 with the UMBC-LACO Rainbow Polarimetric Imager (RPI)  

NASA Astrophysics Data System (ADS)

The UMBC Rainbow Polarimetric Imager is a small form factor VIS imaging polarimeter suitable for use on a number of platforms. An optical system based on a Phillips prism with three Bayer filter color detectors, each detecting a separate polarization state, allows simultaneous detection of polarization and spectral information. A Mueller matrix-like calibration scheme corrects for polarization artifacts in the optical train and allows retrieval of the polarization state of incoming light to better than 0.5%. Coupled with wide field of view optics (~90°), RPI can capture images of cloudbows over a wide range of aircraft headings and solar zenith angles for retrieval of cloud droplet size distribution (DSD) parameters. In May-June 2012, RPI was flown in a nadir port on the NASA DC-8 during the DC3 field campaign. We will show examples of cloudbow DSD parameter retrievals from the campaign to demonstrate the efficacy of such a system to terrestrial atmospheric remote sensing. RPI image from DC3 06/15/2012 flight. Left panel is raw image from the RPI 90° camera. Middle panel is Stokes 'q' parameter retrieved from full three camera dataset. Right panel is a horizontal cut in 'q' through the glory. Both middle and right panels clearly show cloudbow features which can be fit to infer cloud DSD parameters.

Buczkowski, S.; Martins, J.; Fernandez-Borda, R.; Cieslak, D.; Hall, J.

2013-12-01

245

Milliarcsecond imaging of clumpy dust clouds in the red giant L2 Pup with the Very Large Telescope Interferometer  

NASA Astrophysics Data System (ADS)

Despite its importance in mass loss, the dust formation in AGB stars is not yet understood well. There is growing evidence that the dust envelopes of AGB stars are much more complex--clumpy and/or bipolar--than spherically expanding shells. The non-spherical structures emerging in AGB stars may be the seed of asymmetry in planetary nebulae. However, direct observations of the clumpy dust cloud formation close to the star is difficult, because we need milliarcsecond spatial resolution. We present milliarcsecond resolution near-IR imaging of the bright, nearby M giant L2 Pup. The 2.2 micron image taken with VLT/NACO at a spatial resolution of 54 mas shows an asymmetric circumstellar envelope with 300 x 200 mas (12 x 8 stellar radii), elongated in East-West direction. Furthermore, we succeeded in aperture-synthesis imaging of L2 Pup by combining these single-dish VLT/NACO data with near-IR interferometric data taken with the AMBER instrument at the Very Large Telescope Interferometer. The reconstructed image with a spatial resolution of 12 mas shows two clumps at 20--30 mas away from the star, as well as another clump over the stellar. This is the first imaging of clumpy dust clouds toward L2 Pup, whose presence was only inferred from polarimetric and photometric observations. Our observations reveal the clumpy dust formation close to the star, at 1.5--2.5 stellar radii.

Ohnaka, K.; Schertl, D.; Hofmann, K. H.; Weigelt, G.

2014-04-01

246

Cloud Screening and Quality Control Algorithm for Star Photometer Data: Assessment with Lidar Measurements and with All-sky Images  

NASA Technical Reports Server (NTRS)

This paper presents the development and set up of a cloud screening and data quality control algorithm for a star photometer based on CCD camera as detector. These algorithms are necessary for passive remote sensing techniques to retrieve the columnar aerosol optical depth, delta Ae(lambda), and precipitable water vapor content, W, at nighttime. This cloud screening procedure consists of calculating moving averages of delta Ae() and W under different time-windows combined with a procedure for detecting outliers. Additionally, to avoid undesirable Ae(lambda) and W fluctuations caused by the atmospheric turbulence, the data are averaged on 30 min. The algorithm is applied to the star photometer deployed in the city of Granada (37.16 N, 3.60 W, 680 ma.s.l.; South-East of Spain) for the measurements acquired between March 2007 and September 2009. The algorithm is evaluated with correlative measurements registered by a lidar system and also with all-sky images obtained at the sunset and sunrise of the previous and following days. Promising results are obtained detecting cloud-affected data. Additionally, the cloud screening algorithm has been evaluated under different aerosol conditions including Saharan dust intrusion, biomass burning and pollution events.

Ramirez, Daniel Perez; Lyamani, H.; Olmo, F. J.; Whiteman, D. N.; Navas-Guzman, F.; Alados-Arboledas, L.

2012-01-01

247

Cloud-to-ground lightning and upper-air patterns during bursts and breaks in the southwest monsoon  

SciTech Connect

Convective bursts and breaks in the southwest U.S. monsoon are investigated in a lightning context because cloud-to-ground (CG) lightning is an excellent indicator of deep convection. Bursts and breaks are identified using six years of Bureau of Land Management CG lightning information. Composited upper-air analyses for 12 bursts and 10 breaks are developed to examine the synoptic-scale differences between these two regimes. Anomaly patterns are investigated, and average burst and break regimes are presented. This investigation shows the importance of moisture, the location of the subtropical ridge axis, and the high-plateau thermal low. For the burst, the ridge axis is displaced northward across Arizona and New Mexico and moisture is usually abundant in the southwestern United States. During the break, the ridge retreats southward into northern Mexico, giving way to dry westerly winds across Arizona. The high-plateau thermal low is firmly in place during July and August, and it pulls-low-level moist air upslope into the Great Basin from the Gulf of California through the only opening available, which is the lower desert of Arizona.

Watson, A.I.; Holle, R.L.; Lopez, R.E. [NOAA, Norman, OK (United States)] [NOAA, Norman, OK (United States)

1994-08-01

248

International Symposium on Pattern Recognition and Acoustical Imaging, Newport Beach, CA, Feb. 4-6, 1987, Proceedings  

SciTech Connect

Various papers on pattern recognition and acoustical imaging are presented. The general subjects considered include imaging, texture and speckle analysis in medical ultrasound, parameter estimation, material characterization and NDE, and pattern recognition. Individual topics discussed include: inverse scattering theory foundations of tomography with diffracting wavefields, acoustical image reconstruction algorithms, three-dimensional motion parameter estimation by holographic acoustical systems, pattern recognition in acoustic emission experiments, image reconstruction of flaws using ramp response signatures, and pattern recognition approach to nondestructive evaluation of materials.

Ferrari, L.A.

1987-01-01

249

Saturn’s Zonal Winds at Cloud Level between 2004-2013 from Cassini ISS Images  

NASA Astrophysics Data System (ADS)

We examine images of Saturn returned by Cassini orbiter’s Imaging Science Subsystem (ISS) camera between 2004 to 2013 to analyze the temporal evolution of the zonal mean wind speed as a function of latitude. Our study primarily examines the images captured in the 752-nm continuum band using the CB2 filter. Images captured using the CB2 filter sense the upper troposphere of Saturn between 350 mbar and 500 mbar (Pérez-Hoyos and Sánchez-Lavega, 2006; Sánchez-Lavega et al, 2006; García-Melendo et al, 2009). We measure the wind speed using a two-dimensional Correlation Imaging Velocimetry (CIV) technique. The wind vectors are computed using pairs of images separated in time by up to two planetary rotations, and binned in latitude to determine the zonal mean wind profile, which typically covers a limited range of latitude. To achieve pole-to-pole coverage, we systematically merge all the wind measurements during each of the calendar years in order to compile a yearly, near-global record of Saturn's zonal wind structure. Using our wind measurements, we analyze the temporal evolution of the zonal wind. We specifically focus on changes in the wind profile after the 2009 equinox; we predict that changes in the insolation pattern caused by the shifting ring shadows affect the horizontal temperature gradient, and change the zonal mean wind through the thermal wind relationship. Furthermore, we also extend the zonal wind analysis by Sayanagi et al (2013), who detected changes in the zonal wind related to the Great Storm of 2010-2011, to study the subsequent evolution of the region affected by the storm. We compare our results with previously published zonal wind profiles obtained from Voyager 1 and 2 (Sánchez-Lavega et al, 2000) and Cassini (García-Melendo et al, 2011). Out study is supported by the Cassini Project, and our investigation is funded by NASA Outer Planets Research Program grant NNX12AR38G and NSF Astronomy and Astrophysics grant 1212216 to KMS.

Blalock, John J.; Sayanagi, Kunio M.; Dyudina, Ulyana A.; Ewald, Shawn P.; Ingersoll , Andrew P.

2014-11-01

250

Resolution analysis in computational imaging with patterned illumination and bucket detection.  

PubMed

In computational imaging by pattern projection, a sequence of microstructured light patterns codified onto a programmable spatial light modulator is used to sample an object. The patterns are used as generalized measurement modes where the object information is expressed. In this Letter, we show that the resolution of the recovered image is only limited by the numerical aperture of the projecting optics regardless of the quality of the collection optics. We provide proof-of-principle experiments where the single-pixel detection strategy outperforms the resolution achieved using a conventional optical array detector for optical imaging. It is advantageous in the presence of real-world conditions, such as optical aberrations and optical imperfections in between the sample and the sensor. We provide experimental verification of image retrieval even when an optical diffuser prevents imaging with a megapixel array camera. PMID:24978763

Rodríguez, A D; Clemente, P; Irles, E; Tajahuerce, E; Lancis, J

2014-07-01

251

Coherence measurements of a Nd-YAG laser by image processing of Michelson interferometer fringe patterns  

Microsoft Academic Search

To determine the coherence of a laser device, the concept of visibility is used and applied to the measured interference patterns produced by this laser light in a specific interferometer. In this case, to determine the coherence of a Diode Pumped Solid State Nd -YAG Laser, a digital image processing procedure was developed and applied to the fringe patterns obtained

Claudia Valdés; Efraín Solarte

2005-01-01

252

Statistical analysis of granular gases, pattern formation, and crumpling through real space imaging  

Microsoft Academic Search

The statistical properties of driven dissipative systems is investigated experimentally with the use of high speed, and high resolution imaging. A variety of experiments that range from idealized granular gases to systems with anisotropic interactions and pattern formation is explored. These experiments can be divided into three classes: granular gases, granular fluids with anisotropic interactions, and pattern formation. The statistical

Daniel L. Blair

2004-01-01

253

Airborne Digital In-Line Holographic System for 3-D Imaging of Cloud Particles  

Microsoft Academic Search

We have developed an airborne holographic instrument for obtaining cloud particle sizes and shapes and their three-dimensional spatial distribution. The primary scientific motivation for the instrument is to provide in-situ measurements of cloud particle spatial correlations, conditioned on particle size. Accurate quantification of spatial correlations at cm-scales and below has been elusive, in part because only one-dimensional spacing data have

J. P. Fugal; E. Saw; A. V. Sergeyev; R. A. Shaw

2003-01-01

254

Active probing of cloud thickness and optical depth using wide-angle imaging LIDAR  

Microsoft Academic Search

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is

Steven P. Love; Anthony B. Davis; Charles A. Rohde; Larry Tellier; Cheng Ho

2002-01-01

255

Global ice cloud observations: radiative properties and statistics from moderate-resolution imaging spectroradiometer measurements  

E-print Network

). Global statistics of ice clouds have been inferred from the High resolution Infrared Radiation Sounder (HIRS) on the National Oceanic and Atmospheric Administration (NOAA) satellites (Wylie et al., 1994; Wylie and Menzel, 3 1999; Wylie et al., 2005...). Global statistics of ice clouds have been inferred from the High resolution Infrared Radiation Sounder (HIRS) on the National Oceanic and Atmospheric Administration (NOAA) satellites (Wylie et al., 1994; Wylie and Menzel, 3 1999; Wylie et al., 2005...

Meyer, Kerry Glynne

2009-05-15

256

Pattern Analysis of Dermoscopic Images Based on FSCM Color Markov Random Fields  

Microsoft Academic Search

In this paper a method for pattern analysis in dermoscopic images of abnormally pigmented skin (melanocytic lesions) is presented.\\u000a In order to diagnose a possible skin cancer, physicians assess the lesion according to different rules. The new trend in Dermatology\\u000a is to classify the lesion by means of pattern irregularity. In order to analyze the pattern turbulence, lesions ought to

Carlos S. Mendoza; Carmen Serrano; Begoña Acha

2009-01-01

257

MATCHING CANVAS WEAVE PATTERNS FROM PROCESSING X-RAY IMAGES OF MASTER PAINTINGS  

E-print Network

MATCHING CANVAS WEAVE PATTERNS FROM PROCESSING X-RAY IMAGES OF MASTER PAINTINGS Don H. Johnson Conservation Department Rice University Cornell University Van Gogh Museum ABSTRACT Thread counting algorithms seek to determine from x-ray images the vertical and horizontal thread counts (frequen- cies

258

The autocorrelation function of polychromatic laser speckle patterns near the image plane  

Microsoft Academic Search

The autocorrelation function of polychromatic speckle patterns produced near the image plane of a double diffraction imaging system is experimentally studied. The condition under which the polychromatic speckle field obeys Gaussian statistics is further investigated as a function of the numberN of scattering cells, using the average contrast of the speckle intensity fluctuations. The profile of the autocorrelation function is

N. Nagamatsu; K. Nakagawa; T. Asakura; K. Morishita

1983-01-01

259

Iron whisker domain patterns imaged by garnet films  

Microsoft Academic Search

Bismuth doped yttrium iron garnet thin films formed on the surfaces of a gadolinium gallium garnet substrate are used as magneto-optical indicators for quantitative studies of the micromagnetics of an iron whisker. The method does not require image processing. A field applied perpendicular to the whisker axis splits a 180° domain wall into two 90° sections slightly separated by a

J.-G. Lee; S. A. Govorkov; A. S. Arrott

1996-01-01

260

The Automatic Assessment and Reduction of Noise Using Edge Pattern Analysis in Nonlinear Image Enhancement  

NASA Technical Reports Server (NTRS)

Noise is the primary visibility limit in the process of non-linear image enhancement, and is no longer a statistically stable additive noise in the post-enhancement image. Therefore novel approaches are needed to both assess and reduce spatially variable noise at this stage in overall image processing. Here we will examine the use of edge pattern analysis both for automatic assessment of spatially variable noise and as a foundation for new noise reduction methods.

Jobson, Daniel J.; Rahman, Zia-ur; Woodells, Glenn A.; Hines, Glenn D.

2004-01-01

261

Periodic patterning using aerial image modulation with optical lithography  

NASA Astrophysics Data System (ADS)

Photolithography for patterns with periodicity in the illumination plane (2.5-D lithography) has seen rapid advances over the past decade, with the introduction of holographic lithography and the further development of phase-contrast and grayscale photolithography methods. However, each of these techniques suffers from substantial difficulties preventing further integration into device fabrication: a lack of parallel processing capabilities and dimension limitations. Here, we present a demonstration of controlled layer topography through modulation of both the exposure dose and exposure focal plane yielding reproducible 2.5-D patterns which are applied to the further development of plasmonic gratings. This process is entirely compatible with commercially available i-line photolithography and etch hardware, enabling a path to ready integration.

Penkov, Boyan; Bordonaro, Garry; Golovin, Andrii B.; Bendoym, Igor; Tennant, Donald M.; Crouse, David T.

2013-07-01

262

High-resolution fluorescence imaging via pattern-illuminated Fourier ptychography.  

PubMed

Fluorescence microscopy plays a vital role in modern biological research and clinical diagnosis. Here, we report an imaging approach, termed pattern-illuminated Fourier ptychography (FP), for fluorescence imaging beyond the diffraction limit of the employed optics. This approach iteratively recovers a high-resolution fluorescence image from many pattern-illuminated low-resolution intensity measurements. The recovery process starts with one low-resolution measurement as the initial guess. This initial guess is then sequentially updated by other measurements, both in the spatial and Fourier domains. In the spatial domain, we use the pattern-illuminated low-resolution images as intensity constraints for the sample estimate. In the Fourier domain, we use the incoherent optical-transfer-function of the objective lens as the object support constraint for the solution. The sequential updating process is then repeated until the sample estimate converges, typically for 5-20 times. Different from the conventional structured illumination microscopy, any unknown pattern can be used for sample illumination in the reported framework. In particular, we are able to recover both the high-resolution sample image and the unknown illumination pattern at the same time. As a demonstration, we improved the resolution of a conventional fluorescence microscope beyond the diffraction limit of the employed optics. The reported approach may provide an alternative solution for structure illumination microscopy and find applications in wide-field, high-resolution fluorescence imaging. PMID:25321288

Dong, Siyuan; Nanda, Pariksheet; Shiradkar, Radhika; Guo, Kaikai; Zheng, Guoan

2014-08-25

263

Integration of Color and Local Derivative Pattern Features for Content-Based Image Indexing and Retrieval  

NASA Astrophysics Data System (ADS)

This paper presents two new feature descriptors for content based image retrieval (CBIR) application. The proposed two descriptors are named as color local derivative patterns (CLDP) and inter color local derivative pattern (ICLDP). In order to reduce the computational complexity the uniform patterns are applied to both CLDP and ICLDP. Further, uniform CLDP (CLDPu2) and uniform ICLDP (ICLDPu2) are generated respectively. The proposed descriptors are able to exploit individual (R, G and B) spectral channel information and co-relating pair (RG, GB, BR, etc.) of spectral channel information. The retrieval performances of the proposed descriptors (CLDP and ICLDP) are tested by conducting two experiments on Corel-5000 and Corel-10000 benchmark databases. The results after investigation show a significant improvement in terms of precision, average retrieval precision (ARP), recall and average retrieval rate (ARR) as compared to local binary patterns (LBP), local derivative patterns (LDP) and other state-of-the-art techniques for image retrieval.

Vipparthi, Santosh Kumar; Nagar, Shyam Krishna

2014-09-01

264

Effective hybrid processor to compute image moments for pattern recognition.  

PubMed

A hybrid optical-digital processor is presented for computing the invariant moments of images in real time, which consists of a holographic mask, two lenses, a charge-coupled-device detector, and a microcomputer. The processor is tested by inputting some roman letters, and the produced results show that the invariant moments of a letter are approximately independent of shift and rotation and that the moments are distinct with different letters. PMID:19774028

Chen, Y S; Zheng, S H; Li, D H

1991-05-01

265

The embedded young stars in the Taurus-Auriga molecular cloud. II - Models for scattered light images  

NASA Technical Reports Server (NTRS)

We describe NIR imaging observations of embedded young stars in the Taurus-Auriga molecular cloud. We find a large range in J-K and H-K colors for these class I sources. The bluest objects have colors similar to the reddest T Tauri stars in the cloud; redder objects lie slightly above the reddening line for standard ISM dust and have apparent K extinctions of up to 5 mag. Most of these sources also show extended NIR emission on scales of 10-20 arcsec which corresponds to linear sizes of 1500-3000 AU. The NIR colors and nebular morphologies for this sample and the magnitude of linear polarization in several sources suggest scattered light produces most of the NIR emission in these objects. We present modeling results that suggest mass infall rates that agree with predictions for cold clouds and are generally consistent with rates estimated from radiative equilibrium models. For reasonable dust grain parameters, the range of colors and extinctions require flattened density distributions with polar cavities evacuated by bipolar outflows. These results support the idea that infall and outflow occur simultaneously in deeply embedded bipolar outflow sources. The data also indicate fairly large centrifugal radii and large inclinations to the rotational axis for a typical source.

Kenyon, Scott J.; Whitney, Barbara A.; Gomez, Mercedes; Hartmann, Lee

1993-01-01

266

Fabrication of multifaceted, micropatterned surfaces and image-guided patterning using laser scanning lithography.  

PubMed

This protocol describes the implementation of laser scanning lithography (LSL) for the fabrication of multifaceted, patterned surfaces and for image-guided patterning. This photothermal-based patterning technique allows for selective removal of desired regions of an alkanethiol self-assembled monolayer on a metal film through raster scanning a focused 532 nm laser using a commercially available laser scanning confocal microscope. Unlike traditional photolithography methods, this technique does not require the use of a physical master and instead utilizes digital "virtual masks" that can be modified "on the fly" allowing for quick pattern modifications. The process to create multifaceted, micropatterned surfaces, surfaces that display pattern arrays of multiple biomolecules with each molecule confined to its own array, is described in detail. The generation of pattern configurations from user-chosen images, image-guided LSL is also described. This protocol outlines LSL in four basic sections. The first section details substrate preparation and includes cleaning of glass coverslips, metal deposition, and alkanethiol functionalization. The second section describes two ways to define pattern configurations, the first through manual input of pattern coordinates and dimensions using Zeiss AIM software and the second via image-guided pattern generation using a custom-written MATLAB script. The third section describes the details of the patterning procedure and postpatterning functionalization with an alkanethiol, protein, and both, and the fourth section covers cell seeding and culture. We end with a general discussion concerning the pitfalls of LSL and present potential improvements that can be made to the technique. PMID:24439286

Slater, John H; West, Jennifer L

2014-01-01

267

[A cloud detection algorithm for MODIS images combining Kmeans clustering and multi-spectral threshold method].  

PubMed

An improved method for detecting cloud combining Kmeans clustering and the multi-spectral threshold approach is described. On the basis of landmark spectrum analysis, MODIS data is categorized into two major types initially by Kmeans method. The first class includes clouds, smoke and snow, and the second class includes vegetation, water and land. Then a multi-spectral threshold detection is applied to eliminate interference such as smoke and snow for the first class. The method is tested with MODIS data at different time under different underlying surface conditions. By visual method to test the performance of the algorithm, it was found that the algorithm can effectively detect smaller area of cloud pixels and exclude the interference of underlying surface, which provides a good foundation for the next fire detection approach. PMID:21714260

Wang, Wei; Song, Wei-Guo; Liu, Shi-Xing; Zhang, Yong-Ming; Zheng, Hong-Yang; Tian, Wei

2011-04-01

268

Sensitivity of Satellite-Retrieved Cloud Properties to the Effective Variance of Cloud Droplet Size Distribution  

SciTech Connect

Cloud reflectance models currently used in cloud property retrievals from satellites have been developed using size distributions defined by a set of fixed effective radii with a fixed effective variance. The satellite retrievals used for the Atmospheric Radiation Measurement (ARM) program assume droplet size distributions with an effective variance value of 0.10 (Minnis et al. 1998); the International Satellite Cloud Climatology Project uses 0.15 (Rossow and Schiffer 1999); and the Moderate Resolution Imaging Spectroradiometer (MODIS) team uses 0.13 (Nakajima and King 1990). These distributions are not necessarily representative of the actual sizes present in the clouds being observed. Because the assumed distributions can affect the reflectance patterns and near-infrared absorption, even for the same droplet effective radius reff, it is desirable to use the optimal size distributions in satellite retrievals of cloud properties. Collocated observations of the same clouds from different geostationary satellites, at different viewing angles, indicate that the current models may not be optimal (Ayers et al. 2005). Similarly, hour-to-hour variations in effective radius and optical depth reveal an unexplained dependence on scattering angle. To explore this issue, this paper examines the sensitivity of the cloud reflectance at 0.65 and 3.90-{micro}m to changes in the effective variance, or the spectral dispersion, of the modeled size distributions. The effects on the scattering phase functions and on the cloud reflectances are presented, as well as some resultant effects on the retrieved cloud properties.

Arduini, R.F.; Minnis, P.; Smith, W.L.Jr.; Ayers, J.K.; Khaiyer, M.M.; Heck, P.

2005-03-18

269

Investigation of mesoscale cloud features viewed by LANDSAT  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Some 50 LANDSAT images displaying mesoscale cloud features were analyzed. This analysis was based on the Rayleigh-Kuettner model describing the formation of that type of mesoscale cloud feature. This model lends itself to computation of the average wind speed in northerly flow from the dimensions of the cloud band configurations measured from a LANDSAT image. In nearly every case, necessary conditions of a curved wind profile and orientation of the cloud streets within 20 degrees of the direction of the mean wind in the convective layer were met. Verification of the results by direct observation was hampered, however, by the incompatibility of the resolution of conventional rawinsonde observations with the scale of the banded cloud patterns measured from LANDSAT data. Comparison seems to be somewhat better in northerly flows than in southerly flows, with the largest discrepancies in wind speed being within 8m/sec, or a factor of two.

Sherr, P. E. (principal investigator); Feteris, P. J.; Lisa, A. S.; Bowley, C. J.; Fowler, M. G.; Barnes, J. C.

1976-01-01

270

Multichannel analysis of correlation length of SEVIRI images around ground-based cloud observatories to determine their representativeness  

NASA Astrophysics Data System (ADS)

Images of the geostationary Meteosat-9 SEVIRI instrument during the year 2012 are analyzed with respect to the representativeness of the observations of eight cloud observatories in Europe. Cloudy situations are selected to get a time series for every pixel in a 300 km × 300 km area centered around each ground station. Then the Pearson correlation coefficient of each time series to the one of the pixel nearest to the corresponding ground site is calculated. The area for which a station is representative is defined by the characteristic radius around each station for each SEVIRI channel, where the average correlation falls below 0.9. It is found that measurements in the visible and near infrared channels, which respond to cloud microphysics, are correlated in an area with a 1 to 4 km radius, while the thermal channels, that correspond to cloud top temperature, are correlated to a distance of about 20 km. The defined radius even increases for the water vapor and ozone channels. While all stations in Central Europe are quite alike, the correlations around the station in the mountains of southern Italy are much lower. Additionally correlations at different distances corresponding to the grid box sizes of forecast models were compared. The results show good comparability between regional forecast models (grid size ? 10 km) and ground-based measurements since the correlations in less than 10 km distance are in all cases higher than 0.8. For larger distances like they are typical for global models (grid size ? 20 km) the correlations decrease to 0.6, especially for shortwave measurements and corresponding cloud products. By comparing daily means, the characteristic radius of each station is increased to about 3 to 10 times the value of instantaneous measurements and also the comparability to models grows.

Slobodda, J.; Hünerbein, A.; Lindstrot, R.; Preusker, R.; Ebell, K.; Fischer, J.

2014-06-01

271

A Novel Strategy for Quantum Image Steganography Based on Moiré Pattern  

NASA Astrophysics Data System (ADS)

Image steganography technique is widely used to realize the secrecy transmission. Although its strategies on classical computers have been extensively researched, there are few studies on such strategies on quantum computers. Therefore, in this paper, a novel, secure and keyless steganography approach for images on quantum computers is proposed based on Moiré pattern. Algorithms based on the Moiré pattern are proposed for binary image embedding and extraction. Based on the novel enhanced quantum representation of digital images (NEQR), recursive and progressively layered quantum circuits for embedding and extraction operations are designed. In the end, experiments are done to verify the validity and robustness of proposed methods, which confirms that the approach in this paper is effective in quantum image steganography strategy.

Jiang, Nan; Wang, Luo

2014-08-01

272

Spatial Uncertainty Modeling of Fuzzy Information in Images for Pattern Classification  

PubMed Central

The modeling of the spatial distribution of image properties is important for many pattern recognition problems in science and engineering. Mathematical methods are needed to quantify the variability of this spatial distribution based on which a decision of classification can be made in an optimal sense. However, image properties are often subject to uncertainty due to both incomplete and imprecise information. This paper presents an integrated approach for estimating the spatial uncertainty of vagueness in images using the theory of geostatistics and the calculus of probability measures of fuzzy events. Such a model for the quantification of spatial uncertainty is utilized as a new image feature extraction method, based on which classifiers can be trained to perform the task of pattern recognition. Applications of the proposed algorithm to the classification of various types of image data suggest the usefulness of the proposed uncertainty modeling technique for texture feature extraction. PMID:25157744

Pham, Tuan D.

2014-01-01

273

Local binary pattern texture-based classification of solid masses in ultrasound breast images  

NASA Astrophysics Data System (ADS)

Breast cancer is one of the leading causes of cancer mortality among women. Ultrasound examination can be used to assess breast masses, complementarily to mammography. Ultrasound images reveal tissue information in its echoic patterns. Therefore, pattern recognition techniques can facilitate classification of lesions and thereby reduce the number of unnecessary biopsies. Our hypothesis was that image texture features on the boundary of a lesion and its vicinity can be used to classify masses. We have used intensity-independent and rotation-invariant texture features, known as Local Binary Patterns (LBP). The classifier selected was K-nearest neighbors. Our breast ultrasound image database consisted of 100 patient images (50 benign and 50 malignant cases). The determination of whether the mass was benign or malignant was done through biopsy and pathology assessment. The training set consisted of sixty images, randomly chosen from the database of 100 patients. The testing set consisted of forty images to be classified. The results with a multi-fold cross validation of 100 iterations produced a robust evaluation. The highest performance was observed for feature LBP with 24 symmetrically distributed neighbors over a circle of radius 3 (LBP24,3) with an accuracy rate of 81.0%. We also investigated an approach with a score of malignancy assigned to the images in the test set. This approach provided an ROC curve with Az of 0.803. The analysis of texture features over the boundary of solid masses showed promise for malignancy classification in ultrasound breast images.

Matsumoto, Monica M. S.; Sehgal, Chandra M.; Udupa, Jayaram K.

2012-03-01

274

Patterns  

NSDL National Science Digital Library

Directions: Play the games that are listed. Do not go to another site. Be sure to take turns with your partner. First, learn to complete a pattern by playing "Which One?." Next, keep practicing patterns by playing "Pattern Mania." Finally, determine what type of pattern each set is by playing "Which pattern is it?." ...

Hinson, Mrs.

2011-10-03

275

On the angular radiance closure of tropical cumulus congestus clouds observed by the Multiangle Imaging Spectroradiometer  

E-print Network

) a volume extinction coefficient proportional to the two-thirds power of height (the adiabatic assumption to the solar illumination of some optically thick cloud surfaces and to specular reflection pervading through appreciated by any aircraft passenger in the Tropics. The very definition of cumulus congestus suggests strong

Zuidema, Paquita

276

Integration of Image Data for Refining Building Boundaries Derived from Point Clouds  

NASA Astrophysics Data System (ADS)

Geometrically and topologically correct 3D building models are required to satisfy with new demands such as 3D cadastre, map updating, and decision making. More attention on building reconstruction has been paid using Airborne Laser Scanning (ALS) point cloud data. The planimetric accuracy of roof outlines, including step-edges is questionable in building models derived from only point clouds. This paper presents a new approach for the detection of accurate building boundaries by merging point clouds acquired by ALS and aerial photographs. It comprises two major parts: reconstruction of initial roof models from point clouds only, and refinement of their boundaries. A shortest closed circle (graph) analysis method is employed to generate building models in the first step. Having the advantages of high reliability, this method provides reconstruction without prior knowledge of primitive building types even when complex height jumps and various types of building roof are available. The accurate position of boundaries of the initial models is determined by the integration of the edges extracted from aerial photographs. In this process, scene constraints defined based on the initial roof models are introduced as the initial roof models are representing explicit unambiguous geometries about the scene. Experiments were conducted using the ISPRS benchmark test data. Based on test results, we show that the proposed approach can reconstruct 3D building models with higher geometrical (planimetry and vertical) and topological accuracy.

Perera, S. N.; Hetti Arachchige, N.; Schneider, D.

2014-08-01

277

Cardiac electrophysiological activation pattern estimation from images using a patient-specific database of synthetic image sequences.  

PubMed

While abnormal patterns of cardiac electrophysiological activation are at the origin of important cardiovascular diseases (e.g., arrhythmia, asynchrony), the only clinically available method to observe detailed left ventricular endocardial surface activation pattern is through invasive catheter mapping. However, this electrophysiological activation controls the onset of the mechanical contraction; therefore, important information about the electrophysiology could be deduced from the detailed observation of the resulting motion patterns. In this paper, we present the study of this inverse cardiac electrokinematic relationship. The objective is to predict the activation pattern knowing the cardiac motion from the analysis of cardiac image sequences. To achieve this, we propose to create a rich patient-specific database of synthetic time series of the cardiac images using simulations of a personalized cardiac electromechanical model, in order to study this complex relationship between electrical activity and kinematic patterns in the context of this specific patient. We use this database to train a machine-learning algorithm which estimates the depolarization times of each cardiac segment from global and regional kinematic descriptors based on displacements or strains and their derivatives. Finally, we use this learning to estimate the patient’s electrical activation times using the acquired clinical images. Experiments on the inverse electrokinematic learning are demonstrated on synthetic sequences and are evaluated on clinical data with promising results. The error calculated between our prediction and the invasive intracardiac mapping ground truth is relatively small (around 10 ms for ischemic patients and 20 ms for nonischemic patient). This approach suggests the possibility of noninvasive electrophysiological pattern estimation using cardiac motion imaging. PMID:24058008

Prakosa, Adityo; Sermesant, Maxime; Allain, Pascal; Villain, Nicolas; Rinaldi, C Aldo; Rhode, Kawal; Razavi, Reza; Delingette, Hervé; Ayache, Nicholas

2014-02-01

278

First correlated measurements of the shape and scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe  

NASA Astrophysics Data System (ADS)

Studying the radiative impact of cirrus clouds requires the knowledge of the link between their microphysics and the single scattering properties of the cloud particles. Usually, this link is created by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS) designed to measure the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles, simultaneously. Clouds containing particles ranging in size from a few micrometers to about 800 ?m diameter can be systematically characterized with an optical resolution power of 2 ?m and polar scattering resolution of 1° for forward scattering directions (from 1° to 10°) and 8° for side and backscattering directions (from 18° to 170°). The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns which were conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced comparable size distributions and images to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF) program. PHIPS is candidate to be a novel air borne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurements instruments.

Abdelmonem, A.; Schnaiter, M.; Amsler, P.; Hesse, E.; Meyer, J.; Leisner, T.

2011-05-01

279

First correlated measurements of the shape and light scattering properties of cloud particles using the new Particle Habit Imaging and Polar Scattering (PHIPS) probe  

NASA Astrophysics Data System (ADS)

Studying the radiative impact of cirrus clouds requires knowledge of the relationship between their microphysics and the single scattering properties of cloud particles. Usually, this relationship is obtained by modeling the optical scattering properties from in situ measurements of ice crystal size distributions. The measured size distribution and the assumed particle shape might be erroneous in case of non-spherical ice particles. We present here a novel optical sensor (the Particle Habit Imaging and Polar Scattering probe, PHIPS) designed to measure simultaneously the 3-D morphology and the corresponding optical and microphysical parameters of individual cloud particles. Clouds containing particles ranging from a few micrometers to about 800 ?m diameter in size can be characterized systematically with an optical resolution power of 2 ?m and polar scattering resolution of 1° for forward scattering directions (from 1° to 10°) and 8° for side and backscattering directions (from 18° to 170°). The maximum acquisition rates for scattering phase functions and images are 262 KHz and 10 Hz, respectively. Some preliminary results collected in two ice cloud campaigns conducted in the AIDA cloud simulation chamber are presented. PHIPS showed reliability in operation and produced size distributions and images comparable to those given by other certified cloud particles instruments. A 3-D model of a hexagonal ice plate is constructed and the corresponding scattering phase function is compared to that modeled using the Ray Tracing with Diffraction on Facets (RTDF) program. PHIPS is a highly promising novel airborne optical sensor for studying the radiative impact of cirrus clouds and correlating the particle habit-scattering properties which will serve as a reference for other single, or multi-independent, measurement instruments.

Abdelmonem, A.; Schnaiter, M.; Amsler, P.; Hesse, E.; Meyer, J.; Leisner, T.

2011-10-01

280

BIOCAT: a pattern recognition platform for customizable biological image classification and annotation  

PubMed Central

Background Pattern recognition algorithms are useful in bioimage informatics applications such as quantifying cellular and subcellular objects, annotating gene expressions, and classifying phenotypes. To provide effective and efficient image classification and annotation for the ever-increasing microscopic images, it is desirable to have tools that can combine and compare various algorithms, and build customizable solution for different biological problems. However, current tools often offer a limited solution in generating user-friendly and extensible tools for annotating higher dimensional images that correspond to multiple complicated categories. Results We develop the BIOimage Classification and Annotation Tool (BIOCAT). It is able to apply pattern recognition algorithms to two- and three-dimensional biological image sets as well as regions of interest (ROIs) in individual images for automatic classification and annotation. We also propose a 3D anisotropic wavelet feature extractor for extracting textural features from 3D images with xy-z resolution disparity. The extractor is one of the about 20 built-in algorithms of feature extractors, selectors and classifiers in BIOCAT. The algorithms are modularized so that they can be “chained” in a customizable way to form adaptive solution for various problems, and the plugin-based extensibility gives the tool an open architecture to incorporate future algorithms. We have applied BIOCAT to classification and annotation of images and ROIs of different properties with applications in cell biology and neuroscience. Conclusions BIOCAT provides a user-friendly, portable platform for pattern recognition based biological image classification of two- and three- dimensional images and ROIs. We show, via diverse case studies, that different algorithms and their combinations have different suitability for various problems. The customizability of BIOCAT is thus expected to be useful for providing effective and efficient solutions for a variety of biological problems involving image classification and annotation. We also demonstrate the effectiveness of 3D anisotropic wavelet in classifying both 3D image sets and ROIs. PMID:24090164

2013-01-01

281

Method for reducing Newton's rings pattern in the scanned image reproduced with film scanners  

NASA Astrophysics Data System (ADS)

Newton's rings pattern always blurs the scanned image when scanning a film using a film scanner. Such phenomenon is a kind of equal thickness interference, which is caused by the air layer between the film and the glass of the scanner. A lot of methods were proposed to prevent the interference, such as film holder, anti-Newton's rings glass and emulsion direct imaging technology, etc. Those methods are expensive and lack of flexibility. In this paper, Newton's rings pattern is proved to be a 2-D chirp signal. Then, the fractional Fourier transform, which can be understood as the chirp-based decomposition, is introduced to process Newton's rings pattern. A digital filtering method in the fractional Fourier domain is proposed to reduce the Newton's rings pattern. The effectiveness of the proposed method is verified by simulation. Compared with the traditional optical method, the proposed method is more flexible and low cost.

Lu, Ming-feng; Ni, Guo-qiang; Wang, Tao; Zhang, Feng; Tao, Ran; Yuan, Jun

2013-12-01

282

Local spatial binary pattern: a new feature descriptor for content-based image retrieval  

NASA Astrophysics Data System (ADS)

In this paper, we propose a novel image retrieval algorithm using local spatial binary patterns (LSBP) for contentbased image retrieval. The traditional local binary pattern (LBP) encodes the relationship between the referenced pixel and its surrounding neighbors by calculating gray-level difference, but LBP lacks the spatial distribution information of texture direction. The proposed method encodes spatial relationship of the referenced pixel and its neighbors, based on the gray-level variation patterns of the horizontal, vertical and oblique directions. Additionally, variation between center pixel and its surrounding neighbors is calculated to reflect the magnitude information of the whole image. We compare our method with LBP, uniform LBP (ULBP), completed LBP (CLBP), local ternary pattern (LTP) and local tetra patterns (LTrP) based on three benchmark image databases including, Brodatz texture database(DB1), Corel database(DB2), and MIT VisTex database(DB3). Experiment analysis shows that the proposed method improves the retrieval results from 70.49%/41.30% to 73.26%/46.26% in terms of average precision/average recall on database DB2, from 79.02% to 85.92% and 82.14% to 90.88% in terms of average precision on databases DB1 and DB3, respectively, as compared with the traditional LBP.

Xia, Yu; Wan, Shouhong; Yue, Lihua

2014-01-01

283

Spatial pattern separation of chemicals and frequency-independent components by terahertz spectroscopic imaging  

NASA Astrophysics Data System (ADS)

We separated the component spatial patterns of frequency-dependent absorption in chemicals and frequency-independent components such as plastic, paper, and measurement noise in terahertz (THz) spectroscopic images, using known spectral curves. Our measurement system, which uses a widely tunable coherent THz-wave parametric oscillator source, can image at a specific frequency in the range 1-2 THz. The component patterns of chemicals can easily be extracted by use of the frequency-independent components. This method could be successfully used for nondestructive inspection for the detection of illegal drugs and devices of bioterrorism concealed, e.g., inside mail and packages.

Watanabe, Yuuki; Kawase, Kodo; Ikari, Tomofumi; Ito, Hiromasa; Ishikawa, Youichi; Minamide, Hiroaki

2003-10-01

284

TERAHERTZ RADIATION: Speckle pattern of the images of objects exposed to monochromatic coherent terahertz radiation  

NASA Astrophysics Data System (ADS)

By using a free electron laser and a microbolometer array, real-time images are recorded for the first time in the terahertz range at the rate of up to 90 frames per second. In the case of diffusive illumination of objects by coherent monochromatic radiation, the images consist of speckles. The study of the statistical properties of speckle patterns shows that they are quite accurately described by the theory developed for speckles in the visible range. By averaging a set of images with the help of a rotating scatterer during the exposure time of a frame (20 ms) and by summing statistically independent speckle patterns of many frames, images of the acceptable quality are obtained. The possibilities of terahertz speckle photography and speckle interferometry are discussed.

Vinokurov, Nikolai A.; Dem'yanenko, M. A.; Esaev, D. G.; Knyazev, Boris A.; Kulipanov, Gennadii N.; Chashchina, O. I.; Cherkasskii, Valerii S.

2009-05-01

285

Wavelet-based decomposition and analysis of structural patterns in astronomical images  

E-print Network

Context. Images of spatially resolved astrophysical objects contain a wealth of morphological and dynamical information, and effective extraction of this information is of paramount importance for understanding the physics and evolution of these objects. Algorithms and methods employed presently for this purpose (such as, for instance, Gaussian model fitting) often use simplified approaches for describing the structure of resolved objects. Aims. Automated (unsupervised) methods for structure decomposition and tracking of structural patterns are needed for this purpose, in order to be able to deal with the complexity of structure and large amount of data involved. Methods. A new Wavelet-based Image Segmentation and Evaluation (WISE) method is developed for multiscale decomposition, segmentation, and tracking of structural patterns in astronomical images. Results. The method is tested against simulated images of relativistic jets and applied to data from long-term monitoring of parsec- scale radio jets in 3C 27...

Mertens, Florent

2014-01-01

286

Searching for patterns in remote sensing image databases using neural networks  

NASA Technical Reports Server (NTRS)

We have investigated a method, based on a successful neural network multispectral image classification system, of searching for single patterns in remote sensing databases. While defining the pattern to search for and the feature to be used for that search (spectral, spatial, temporal, etc.) is challenging, a more difficult task is selecting competing patterns to train against the desired pattern. Schemes for competing pattern selection, including random selection and human interpreted selection, are discussed in the context of an example detection of dense urban areas in Landsat Thematic Mapper imagery. When applying the search to multiple images, a simple normalization method can alleviate the problem of inconsistent image calibration. Another potential problem, that of highly compressed data, was found to have a minimal effect on the ability to detect the desired pattern. The neural network algorithm has been implemented using the PVM (Parallel Virtual Machine) library and nearly-optimal speedups have been obtained that help alleviate the long process of searching through imagery.

Paola, Justin D.; Schowengerdt, Robert A.

1995-01-01

287

Imaging surface immobilization chemistry: correlation with cell patterning on non-adhesive hydrogel thin films  

PubMed Central

High-fidelity surface functional group (e.g., N-hydroxysuccinimide (NHS) reactive ester) patterning is readily and reliably achieved on commercial poly(ethylene glycol) (PEG)-based polymer films already known to exhibit high performance non-fouling properties in full serum and in cell culture conditions. NHS coupling chemistry co-patterned with methoxy-capped PEG using photolithographic methods is directly spatially imaged using imaging time-of-flight secondary ion mass spectrometry (ToF-SIMS) and principal components statistical analysis. Patterned NHS surface reactive zones are clearly resolved at high sensitivity despite the complexity of the polymer matrix chemistry. ToF-SIMS imaging also reveals the presence of photo-resist residue remaining from typical photolithography processing methods. High cross-correlation between various ion-derived ToF-SIMS images is observed, providing sensitive chemical corroboration of pattern chemistry and biological reactivity in complex milieu. Surface-specific protein coupling is observed first by site-selective reaction of streptavidin with NHS patterns, followed by identical patterns of biotinylated Alexa-labeled albumin coupling. This suggests that streptavidin immobilized on the patterns remains bioactive. Fluorescently labeled full serum is shown to react selectively with NHS-reactive regions, with minimal signal from methoxy-capped regions. Insufficient serum is adsorbed under any conditions to these surfaces to support cell attachment in serum-containing media. This reflects the high intrinsic non-adsorptive nature of this chemistry. Fibroblasts attach and proliferate in serum culture only when a cell adhesion peptide (RGD) is first grafted to NHS regions on the PEG-based surfaces. Longer-term serum-based cell culture retains high cell-pattern fidelity that correlates with chemical imaging of both the NHS and RGD patterns and also lack of cell adhesion to methoxy-capped regions. Cell staining shows orientation of adherent cells within the narrow patterned areas. Cell patterns are consistently retained beyond 15 days in serum media. PMID:20700474

Takahashi, Hironobu; Emoto, Kazunori; Dubey, Manish; Castner, David G.; Grainger, David W.

2010-01-01

288

Low temperature aSi:H photodiodes and flexible image sensor arrays patterned by digital lithography  

Microsoft Academic Search

Hydrogenated amorphous silicon-based image sensor arrays were fabricated on polyethylene naphthalate substrates, with photodiodes optimized for process temperatures of 150 °C. An optimal i-layer thickness was determined to minimize carrier recombination and to maintain sufficient light absorption and acceptable leakage current. Patterning of the thin-film transistor backplane was accomplished using ink-jet printed etch masks. A flexible image sensor is demonstrated

Tse Nga Ng; Rene A. Lujan; Sanjiv Sambandan; Scott Limb; William S. Wong

2007-01-01

289

Analysis of speckle patterns in phase-contrast images of lung tissue  

Microsoft Academic Search

Propagation-based phase-contrast images of mice lungs have been obtained at the SPring-8 synchrotron research facility. Such images exhibit a speckled intensity pattern that bears a superficial resemblance to alveolar structures. This speckle results from focussing effects as projected air-filled alveoli form aberrated compound refractive lenses. An appropriate phase-retrieval algorithm has been utilized to reconstruct the approximate projected lung tissue thickness

M. J. Kitchen; D. Paganin; R. A. Lewis; N. Yagi; K. Uesugi

2005-01-01

290

Remote sensing of cloud, aerosol, and water vapor properties from the moderate resolution imaging spectrometer (MODIS)  

NASA Technical Reports Server (NTRS)

The authors describe the status of MODIS-N and its companion instrument MODIS-T (tilt), a tiltable cross-track scanning spectrometer with 32 uniformly spaced channels between 0.410 and 0.875 micron. They review the various methods being developed for the remote sensing of atmospheric properties using MODIS, placing primary emphasis on the principal atmospheric applications of determining the optical, microphysical, and physical properties of clouds and aerosol particles from spectral reflection and thermal emission measurements. In addition to cloud and aerosol properties, MODIS-N will be used for determining the total precipitable water vapor and atmospheric stability. The physical principles behind the determination of each of these atmospheric products are described, together with an example of their application to aircraft and/or satellite measurements.

King, Michael D.; Kaufman, Yoram J.; Menzel, W. Paul; Tanre, Didier D.

1992-01-01

291

Spatial and Temporal Distribution of Clouds Observed by MODIS Onboard the Terra and Aqua Satellites  

NASA Technical Reports Server (NTRS)

The Moderate Resolution Imaging Spectroradiometer (MODIS) was developed by NASA and launched aboard the Terra spacecraft on December 18, 1999 and Aqua spacecraft on May 4, 2002. A comprehensive set of remote sensing algorithms for the retrieval of cloud physical and optical properties have enabled over twelve years of continuous observations of cloud properties from Terra and over nine years from Aqua. The archived products from these algorithms include 1 km pixel-level (Level-2) and global gridded Level-3 products. In addition to an extensive cloud mask, products include cloud-top properties (temperature, pressure, effective emissivity), cloud thermodynamic phase, cloud optical and microphysical parameters (optical thickness, effective particle radius, water path), as well as derived statistics. Results include the latitudinal distribution of cloud optical and radiative properties for both liquid water and ice clouds, as well as latitudinal distributions of cloud top pressure and cloud top temperature. MODIS finds the cloud fraction, as derived by the cloud mask, is nearly identical during the day and night, with only modest diurnal variation. Globally, the cloud fraction derived by the MODIS cloud mask is approx.67%, with somewhat more clouds over land during the afternoon and less clouds over ocean in the afternoon, with very little difference in global cloud cover between Terra and Aqua. Overall, cloud fraction over land is approx.55%, with a distinctive seasonal cycle, whereas the ocean cloudiness is much higher, around 72%, with much reduced seasonal variation. Cloud top pressure and temperature have distinct spatial and temporal patterns, and clearly reflect our understanding of the global cloud distribution. High clouds are especially prevalent over the northern hemisphere continents between 30 and 50 . Aqua and Terra have comparable zonal cloud top pressures, with Aqua having somewhat higher clouds (cloud top pressures lower by 100 hPa) over land due to afternoon deep convection. The coldest cloud tops (colder than 230 K) generally occur over Antarctica and the high clouds in the tropics (ITCZ and the deep convective clouds over the western tropical Pacific and Indian sub-continent).

King, Michael D.; Platnick, Steven; Menzel, W. Paul; Ackerman, Steven A.; Hubanks, Paul A.

2012-01-01

292

Laboratory measurements of light scattered by clouds and layers of solid particles using an imaging technique  

Microsoft Academic Search

\\u000a The Optical PRoperties of Astronomical and Atmospheric Grains (PROGRA2) experiment was developed in 1993 to study the light scattered by dust clouds, with an emphasis on its linear polarization.\\u000a The instrument was progressively improved. A short description of the PROGRA2-vis instrument operating in the visible is given in this chapter. In the framework of the experiment, solid particles are\\u000a lifted

E. Hadamcik; J.-B. Renard; A. C. Levasseur-Regourd; J. Lasue

293

Estimation of color modification in digital images by CFA pattern change.  

PubMed

Extensive studies have been carried out for detecting image forgery such as copy-move, re-sampling, blurring, and contrast enhancement. Although color modification is a common forgery technique, there is no reported forensic method for detecting this type of manipulation. In this paper, we propose a novel algorithm for estimating color modification in images acquired from digital cameras when the images are modified. Most commercial digital cameras are equipped with a color filter array (CFA) for acquiring the color information of each pixel. As a result, the images acquired from such digital cameras include a trace from the CFA pattern. This pattern is composed of the basic red green blue (RGB) colors, and it is changed when color modification is carried out on the image. We designed an advanced intermediate value counting method for measuring the change in the CFA pattern and estimating the extent of color modification. The proposed method is verified experimentally by using 10,366 test images. The results confirmed the ability of the proposed method to estimate color modification with high accuracy. PMID:23312844

Choi, Chang-Hee; Lee, Hae-Yeoun; Lee, Heung-Kyu

2013-03-10

294

Cloud Arcs in the Western Pacific  

NASA Technical Reports Server (NTRS)

Small cumulus clouds in this natural-color view from the Multi-angle Imaging SpectroRadiometer have formed a distinctive series of quasi-circular arcs. Clues regarding the formation of these arcs can be found by noting that larger clouds exist in the interior of each arc.

The interior clouds are thicker and likely to be more convectively active than the other clouds, causing much of the air near the centers of the arcs to rise. This air spreads out horizontally in all directions as it rises and continues to spread out as it begins to sink back to the surface. This pushes any existing small cumulus clouds away from the central region of convection.

As the air sinks, it also warms, preventing other small clouds from forming, so that the regions just inside the arcs are kept clear. At the arcs, the horizontal flow of sinking air is now quite weak and on meeting the undisturbed air it can rise again slightly -- possibly assisting in the formation of new small cumulus clouds. Although examples of the continuity of air, in which every rising air motion must be compensated by a sinking motion elsewhere, are very common, the degree of organization exhibited here is relatively rare, as the wind field at different altitudes usually disrupts such patterns. The degree of self organization of this cloud image, whereby three or four such circular events form a quasi-periodic pattern, probably also requires a relatively uncommon combination of wind, temperature and humidity conditions for it to occur.

The image was acquired by MISR's nadir camera on March 11, 2002, and is centered west of the Marshall Islands. Enewetak Atoll is discernible through thin cloud as the turquoise band near the right-hand edge of the image.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously from pole to pole, and views almost the entire globe every 9 days. This image is a portion of the data acquired during Terra orbit 11863, and covers an area of about 380 kilometers x 345 kilometers. It utilizes data from blocks 80 to 82 within World Reference System-2 path 90.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

2002-01-01

295

VENUS CLOUD TOPS VIEWED BY HUBBLE  

NASA Technical Reports Server (NTRS)

This is a NASA Hubble Space Telescope ultraviolet-light image of the planet Venus, taken on January 24 1995, when Venus was at a distance of 70.6 million miles (113.6 million kilometers) from Earth. Venus is covered with clouds made of sulfuric acid, rather than the water-vapor clouds found on Earth. These clouds permanently shroud Venus' volcanic surface, which has been radar mapped by spacecraft and from Earth-based telescope. At ultraviolet wavelengths cloud patterns become distinctive. In particular, a horizontal 'Y'-shaped cloud feature is visible near the equator. Similar features were seen from Mariner 10, Pioneer Venus, and Galileo spacecrafts. This global feature might indicate atmospheric waves, analogous to high and low pressure cells on Earth. Bright clouds toward Venus' poles appear to follow latitude lines. The polar regions are bright, possibly showing a haze of small particles overlying the main clouds. The dark regions show the location of enhanced sulfur dioxide near the cloud tops. From previous missions, astronomers know that such features travel east to west along with the Venus' prevailing winds, to make a complete circuit around the planet in four days. Because Venus is closer to the Sun than Earth, the planet appears to go through phases, like the Moon. When Venus swings close to Earth the planet's disk appears to grow in size, but changes from a full disk to a crescent. The image was taken with the Wide Field Planetary Camera-2, in PC mode. False color has been used enhance cloud features. Credit: L. Esposito (University of Colorado, Boulder), and NASA

2002-01-01

296

A practical approach to optimizing the preparation of speckle patterns for digital-image correlation  

NASA Astrophysics Data System (ADS)

The quality of strain measurements by digital image correlation (DIC) strongly depends on the quality of the pattern on the specimen’s surface. An ideal pattern should be highly contrasted, stochastic, and isotropic. In addition, the speckle pattern should have an average size that exceeds the image pixel size by a factor of 3–5. (Smaller speckles cause poor contrast, and larger speckles cause poor spatial resolution.) Finally, the ideal pattern should have a limited scatter in terms of speckle sizes. The aims of this study were: (i) to define the ideal speckle size in relation to the specimen size and acquisition system; (ii) provide practical guidelines to identify the optimal settings of an airbrush gun, in order to produce a pattern that is as close as possible to the desired one while minimizing the scatter of speckle sizes. Patterns of different sizes were produced using two different airbrush guns with different settings of the four most influential factors (dilution, airflow setting, spraying distance, and air pressure). A full-factorial DOE strategy was implemented to explore the four factors at two levels each: 36 specimens were analyzed for each of the 16 combinations. The images were acquired using the digital cameras of a DIC system. The distribution of speckle sizes was analyzed to calculate the average speckle size and the standard deviation of the corresponding truncated Gaussian distribution. A mathematical model was built to enable prediction of the average speckle size in relation to the airbrush gun settings. We showed that it is possible to obtain a pattern with a highly controlled average and a limited scatter of speckle sizes, so as to match the ideal distribution of speckle sizes for DIC. Although the settings identified here apply only to the specific equipment being used, this method can be adapted to any airbrush to produce a desired speckle pattern.

Lionello, Giacomo; Cristofolini, Luca

2014-10-01

297

Journal of Pattern Recognition Research 1 (2006) 16-32 Image Fusion and Enhancement via Empirical Mode Decomposition  

E-print Network

Journal of Pattern Recognition Research 1 (2006) 16-32 Image Fusion and Enhancement via Empirical, is not common in the literature. Keywords: Data fusion, Empirical mode decomposition, Image fusion, Intrinsic mode function. 1. Introduction Image fusion is the capacity to produce a single fused image from a set

Koschan, Andreas

298

Feature mining and pattern classification for steganalysis of LSB matching steganography in grayscale images  

Microsoft Academic Search

In this paper, we present a scheme based on feature mining and pattern classification to detect LSB matching steganography in grayscale images, which is a very challenging problem in steganalysis. Five types of features are proposed. In comparison with other well-known feature sets, the set of proposed features performs the best. We compare different learning classifiers and deal with the

Qingzhong Liu; Andrew H. Sung; Zhongxue Chen; Jianyun Xu

2008-01-01

299

VITILIGO & NLRP1 Presented by Sarah Hamilton http://www.avrf.org/images/vitiligo-patterns.gif  

E-print Network

VITILIGO & NLRP1 Presented by Sarah Hamilton http://www.avrf.org/images/vitiligo-patterns.gif #12;Vitiligo Facts Autoimmune disease ­ loss of melanocytes Affects 2-4 million Americans; 65 million diseases http://www.bio.davidson.edu/Courses/Immunology/Students/Spring2003/Leese/Vitiligo.jpg #12;Vitiligo

Skop, Ahna

300

Gender Classification from Iris Images using Fusion of Uniform Local Binary Patterns  

E-print Network

Gender Classification from Iris Images using Fusion of Uniform Local Binary Patterns Juan E. Tapia1, this paper is concerned with predicting the gender of a per- son based on analysis of features of the iris texture. Previous researchers have explored various approaches for predicting the gender of a person based

Bowyer, Kevin W.

301

ASAR IMAGES A DIVERSE SET OF DEFORMATION PATTERNS AT KLAUEA VOLCANO, HAWAI`I  

E-print Network

ASAR IMAGES A DIVERSE SET OF DEFORMATION PATTERNS AT KLAUEA VOLCANO, HAWAI`I Michael P. Poland(1) (1) U.S. Geological Survey, Hawaiian Volcano Observatory, 51 Crater Rim Road, Hawai`i National Park. On Klauea volcano, a transition from minor to broad-scale summit inflation was observed by interferograms

302

Various Patterns of Perfusion-Weighted MR Imaging and MR Angiographic Findings in Hyperacute Ischemic Stroke  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Various clinical subtypes of patients presenting with sud- den-onset ischemic stroke have been recognized, but classification of those types is not simple. We identified various patterns of perfusion-weighted MR imaging and MR angiographic find- ings in hyperacute ischemic stroke with relation to clinical outcomes. METHODS: Twelve patients with symptoms of acute ischemic stroke due to middle cerebral

Jae Hyoung Kim; Taemin Shin; Ji Hoon Park; Sung Hoon Chung; Nack-Cheon Choi; Byeong Hoon Lim

303

Quantitative super-resolution imaging uncovers reactivity patterns on single nanocatalysts  

E-print Network

Quantitative super-resolution imaging uncovers reactivity patterns on single nanocatalysts Xiaochun with a known structure1,2,10 , and the reactivity of nanocatalysts can often be rationalized from a knowledge) as nanocatalysts because of their highly anisotropic structure and faceted surfaces (a consequence

Chen, Peng

304

Building a Latent Semantic Index of an Image Database from Patterns of Relevance Feedback  

E-print Network

Building a Latent Semantic Index of an Image Database from Patterns of Relevance Feedback Douglas R-query information then takes the form of a collection of documents which can be subjected to latent semantic analysis. An algorithm to query the latent semantic index is presented and evaluated against real data sets

Heisterkamp, Douglas R.

305

Compact camera for multispectral and conventional imaging based on patterned filters.  

PubMed

A multispectral camera concept is presented. The concept is based on using a patterned filter in the focal plane, combined with scanning of the field of view. The filter layout has stripes of different bandpass filters extending orthogonally to the scan direction. The pattern of filter stripes is such that all bands are sampled multiple times, while minimizing the total duration of the sampling of a given scene point. As a consequence, the filter needs only a small part of the area of an image sensor. The remaining area can be used for conventional 2D imaging. A demonstrator camera has been built with six bands in the visible and near infrared, as well as a panchromatic 2D imaging capability. Image recording and reconstruction is demonstrated, but the quality of image reconstruction is expected to be a main challenge for systems based on this concept. An important advantage is that the camera can potentially be made very compact, and also low cost. It is shown that under assumptions that are not unreasonable, the proposed camera concept can be much smaller than a conventional imaging spectrometer. In principle, it can be smaller in volume by a factor on the order of several hundred while collecting the same amount of light per multispectral band. This makes the proposed camera concept very interesting for small airborne platforms and other applications requiring compact spectral imagers. PMID:24921891

Skauli, Torbjørn; Torkildsen, Hans Erling; Nicolas, Stephane; Opsahl, Thomas; Haavardsholm, Trym; Kåsen, Ingebjørg; Rognmo, Atle

2014-05-01

306

Introduction to Clouds  

NSDL National Science Digital Library

This site provides the user an opportunity to explore storm clouds and climate change through the use of NASA climate research data obtained through satellite imaging. The user is challenged to investigate actual scientific research data on clouds and storms, and make observations and interpretations available to NASA research scientists for review. Topics addressed by these investigations include the role of clouds in relation to the changing climate of Earth, the role of clouds in warming or cooling the planet, and the major types of clouds produced by storms.

Tselioudis, George; Petersen, Christopher

1997-01-01

307

Enabling 35nm double patterning contact imaging using a novel CD shrink process  

NASA Astrophysics Data System (ADS)

With 32nm and 22nm feature size node in the near future, Double patterning type processing will be in mainstream device manufacturing in most cutting edge Fabrication facilities. These type of processes requires cooperation between the litho cell and the other processing modules. In a collaboration between ASML and TEL we have developed a integrated solution to image 30nm Contacts. We describe a novel technique to achieve a geometric shrink from a starting geometry of 65nm down to the final feature size of 30nm for each of the two contact images Processing 2 images separately could produce two distinct populations for alignment and critical dimensions. We will show the ability to image 65nm contacts on a 130nm pitch with acceptable process windows and then apply the novel CD shrink process to shrink the 65nm contacts to 30nm final dimension. The second level of contacts is imaged in between the 1st set of contacts allowing us to image a 32nm ½ pitch contact pattern. We show the ability to Image 2 separate sets of contacts using a split clip layout with a single distribution for critical output parameters. We address the following process challenges: 1) Overlay capability across the slit and across the field. 2) Critical Dimension capability across the slit and across the Field. 3) Sidewall angle integrity with acceptable process window. Using the novel CD shrink process TEL has developed and imaging capability of the an ASML 1700i TWINSCAN, we can achieve a double pattern contact process with acceptable process capability.

Yamada, Yoshiaki; Crouse, Michael M.; Dunn, Shannon; Kawasaki, Tetsu; Shimura, Satoru; Nishimura, Eiichi; Tanaka, Yoshitsugu; Galloway, Judy; Pierson, Bill; Routh, Robert

2008-03-01

308

Characterising the dynamics of expirated bloodstain pattern formation using high-speed digital video imaging.  

PubMed

During forensic investigations, it is often important to be able to distinguish between impact spatter patterns (blood from gunshots, explosives, blunt force trauma and/or machinery accidents) and bloodstain patterns generated by expiration (blood from the mouth, nose or lungs). These patterns can be difficult to distinguish on the basis of the size of the bloodstains. In this study, high-speed digital video imaging has been used to investigate the formation of expirated bloodstain patterns generated by breathing, spitting and coughing mechanisms. Bloodstain patterns from all three expiration mechanisms were dominated by the presence of stains less than 0.5 mm in diameter. Video analysis showed that in the process of coughing blood, high-velocity, very small blood droplets were ejected first. These were followed by lower velocity, larger droplets, strands and plumes of liquid held together in part by saliva. The video images showed the formation of bubble rings and beaded stains, traditional markers for classifying expirated patterns. However, the expulsion mechanism, the distance travelled by the blood droplets, and the type of surface the blood was deposited on were all factors determining whether beaded stains were generated. PMID:20668870

Donaldson, Andrea E; Walker, Nicole K; Lamont, Iain L; Cordiner, Stephen J; Taylor, Michael C

2011-11-01

309

Gallbladder wall thickening: MR imaging and pathologic correlation with emphasis on layered pattern.  

PubMed

The aim of this study was to correlate MR findings of gallbladder wall thickening with pathologic findings on the basis of the layered pattern and to evaluate the diagnostic value of MR imaging in gallbladder disease. We retrospectively evaluated the source images of HASTE sequences for MR cholangiography in 144 patients with gallbladder wall thickening. The layered pattern of thickened wall was classified into four patterns. Type 1 shows two layers with a thin hypointense inner layer and thick hyperintense outer layer. Type 2 has two layers of ill-defined margin. Type 3 shows multiple hyperintense cystic spaces in the wall. Type 4 shows diffuse nodular thickening without layering. MR findings of a layered pattern of thickened gallbladder were well correlated with histopathology. Chronic cholecystitis matched to type 1, acute cholecystitis corresponded to type 2, adenomyomatosis showed type 3, and the gallbladder carcinomas showed type 4. All four layered patterns were associated with PPV of 73% or greater, sensitivity of 92% or greater and specificity of 95% or greater. Our results indicate that MR findings of gallbladder wall thickening are characteristic in each entity and correlate well with pathologic findings. The classification of the layered pattern may be valuable for interpreting thickened gallbladder wall. PMID:15565318

Jung, S E; Lee, J M; Lee, K; Rha, S E; Choi, B G; Kim, E K; Hahn, S T

2005-04-01

310

Hotspot detection using image pattern recognition based on higher-order local auto-correlation  

NASA Astrophysics Data System (ADS)

Below 40nm design node, systematic variation due to lithography must be taken into consideration during the early stage of design. So far, litho-aware design using lithography simulation models has been widely applied to assure that designs are printed on silicon without any error. However, the lithography simulation approach is very time consuming, and under time-to-market pressure, repetitive redesign by this approach may result in the missing of the market window. This paper proposes a fast hotspot detection support method by flexible and intelligent vision system image pattern recognition based on Higher-Order Local Autocorrelation. Our method learns the geometrical properties of the given design data without any defects as normal patterns, and automatically detects the design patterns with hotspots from the test data as abnormal patterns. The Higher-Order Local Autocorrelation method can extract features from the graphic image of design pattern, and computational cost of the extraction is constant regardless of the number of design pattern polygons. This approach can reduce turnaround time (TAT) dramatically only on 1CPU, compared with the conventional simulation-based approach, and by distributed processing, this has proven to deliver linear scalability with each additional CPU.

Maeda, Shimon; Matsunawa, Tetsuaki; Ogawa, Ryuji; Ichikawa, Hirotaka; Takahata, Kazuhiro; Miyairi, Masahiro; Kotani, Toshiya; Nojima, Shigeki; Tanaka, Satoshi; Nakagawa, Kei; Saito, Tamaki; Mimotogi, Shoji; Inoue, Soichi; Nosato, Hirokazu; Sakanashi, Hidenori; Kobayashi, Takumi; Murakawa, Masahiro; Higuchi, Tetsuya; Takahashi, Eiichi; Otsu, Nobuyuki

2011-04-01

311

Developmental Stage Annotation of Drosophila Gene Expression Pattern Images via an Entire Solution Path for LDA.  

PubMed

Gene expression in a developing embryo occurs in particular cells (spatial patterns) in a time-specific manner (temporal patterns), which leads to the differentiation of cell fates. Images of a Drosophila melanogaster embryo at a given developmental stage, showing a particular gene expression pattern revealed by a gene-specific probe, can be compared for spatial overlaps. The comparison is fundamentally important to formulating and testing gene interaction hypotheses. Expression pattern comparison is most biologically meaningful when images from a similar time point (developmental stage) are compared. In this paper, we present LdaPath, a novel formulation of Linear Discriminant Analysis (LDA) for automatic developmental stage range classification. It employs multivariate linear regression with the L(1)-norm penalty controlled by a regularization parameter for feature extraction and visualization. LdaPath computes an entire solution path for all values of regularization parameter with essentially the same computational cost as fitting one LDA model. Thus, it facilitates efficient model selection. It is based on the equivalence relationship between LDA and the least squares method for multi-class classifications. This equivalence relationship is established under a mild condition, which we show empirically to hold for many high-dimensional datasets, such as expression pattern images. Our experiments on a collection of 2705 expression pattern images show the effectiveness of the proposed algorithm. Results also show that the LDA model resulting from LdaPath is sparse, and irrelevant features may be removed. Thus, LdaPath provides a general framework for simultaneous feature selection and feature extraction. PMID:18769656

Ye, Jieping; Chen, Jianhui; Janardan, Ravi; Kumar, Sudhir

2008-03-01

312

APPLICATION OF NON-HYDROSTATIC NUMERICAL MODELS DATA AND METEOROLOGICAL SATELLITES IMAGES TO INVESTIGATION OF AIRCRAFT FLIGHT CONDITIONS WITHIN CLOUDS SYSTEMS  

Microsoft Academic Search

The paper presents research results concerning developing software for determining optimum aircraft flight routes in severe weather. The application uses COAMPS mesoscale model data and MSG satellite images. The analyses concentrate mainly on forecasted fields of clouds and hazardous for aviation atmospheric phenomena - turbulence and icing. Gradient characteristics of the atmospheric state including frontogenetic function, temperature coefficient of fronts

I. Winnicki; J. Jasinski; K. Kroszczynski; S. Pietrek; WG VIII

313

Constraining mass-diameter relations from hydrometeor images and cloud radar reflectivities in tropical continental and oceanic convective anvils  

NASA Astrophysics Data System (ADS)

In this study the density of ice hydrometeors in tropical clouds is derived from a combined analysis of particle images from 2-D-array probes and associated reflectivities measured with a Doppler cloud radar on the same research aircraft. Usually, the mass-diameter m(D) relationship is formulated as a power law with two unknown coefficients (pre-factor, exponent) that need to be constrained from complementary information on hydrometeors, where absolute ice density measurement methods do not apply. Here, at first an extended theoretical study of numerous hydrometeor shapes simulated in 3-D and arbitrarily projected on a 2-D plan allowed to constrain the exponent ?of the m(D) relationship from the exponent ? of the surface-diameterS(D)relationship, which is likewise written as a power law. Since S(D) always can be determined for real data from 2-D optical array probes or other particle imagers, the evolution of the m(D) exponent can be calculated. After that, the pre-factor ? of m(D) is constrained from theoretical simulations of the radar reflectivities matching the measured reflectivities along the aircraft trajectory. The study was performed as part of the Megha-Tropiques satellite project, where two types of mesoscale convective systems (MCS) were investigated: (i) above the African continent and (ii) above the Indian Ocean. For the two data sets, two parameterizations are derived to calculate the vertical variability of m(D) coefficients ? and ? as a function of the temperature. Originally calculated (with T-matrix) and also subsequently parameterized m(D) relationships from this study are compared to other methods (from literature) of calculating m(D) in tropical convection. The significant benefit of using variable m(D) relations instead of a single m(D) relationship is demonstrated from the impact of all these m(D) relations on Z-CWC (Condensed Water Content) and Z-CWC-T-fitted parameterizations.

Fontaine, E.; Schwarzenboeck, A.; Delanoë, J.; Wobrock, W.; Leroy, D.; Dupuy, R.; Gourbeyre, C.; Protat, A.

2014-10-01

314

Mapping of SO2 on Venus within the H2SO4 cloud using ground-based infrared imaging spectroscopy  

NASA Astrophysics Data System (ADS)

Sulfur dioxide and water vapor, two key parameters of Venus' photochemistry, are known to exhibit significant spatial and temporal variations. In particular, ground-based thermal imaging spectroscopy at high resolution, achieved on Venus in January 2012, has shown evidence for strong SO2 variations on timescales shorter than a day (Encrenaz et al. AA 543, 153, 2012). We have continued our observing campaign using the TEXES high-resolution imaging spectrometer at the NASA Infrared Telescope Facility to map sulfur dioxide over the disk of Venus at two different wavelengths, 7 ?m (already used in the previous study) and 19 ?m. The 7 ?m radiation probes the top of the H2SO4 cloud at about 65 km, while the 19 ?m radiation probes at deeper levels within the cloud. Observations took place on October 4 and 5, 2012. The diameter of Venus was 15 arcsec, with an illumination factor of 72%. Data were recorded at 1343-1353 cm-1 during the two first hours of each run and at 529-531 cm-1 during the two last hours. The spectral resolving power and spatial resolution were, respectively, about 70000 and 1 arcsec at 7 ?m, and 60000 and 1.5 arcsec at 19 ?m. The Doppler velocity of Venus was + 12 km/s, corresponding to a Doppler shift of - 0.054 cm-1 at 1350 cm-1 and - 0.021 cm-1 at 530 cm-1. Both HDO and SO2 lines are identified in our 7 ?m spectra and SO2 is also easily identified at 19 ?m; the poor weather and the high water atmospheric content during our observing run limited the quality of the 7 ?m observations. As observed in our previous run, the HDO map is relatively uniform over the disk of Venus. In contrast, the SO2 maps at 19 ?m show intensity variations over the disk, as observed in January 2012 at 7 ?m. In addition, the SO2 map at 19 ?m shows significant changes within a timescale of an hour. The CO2 lines at 7 and 19 ?m will be used to infer the thermal structure within the cloud and to study its latitudinal variations.

Encrenaz, Therese; Greathouse, Thomas; Richter, Matthew; Lacy, John; Bézard, Bruno; Fouchet, Thierry; DeWitt, Curtis; Widemann, Thomas

2013-04-01

315

Waves on White: Ice or Clouds?  

NASA Technical Reports Server (NTRS)

As it passed over Antarctica on December 16, 2004, the Multi-angle Imaging SpectroRadiometer (MISR) on NASA's Terra satellite captured this image showing a wavy pattern in a field of white. At most other latitudes, such wavy patterns would likely indicate stratus or stratocumulus clouds. MISR, however, saw something different. By using information from several of its multiple cameras (each of which views the Earth's surface from a different angle), MISR was able to tell that what looked like a wavy cloud pattern was actually a wavy pattern on the ice surface. One of MISR's cloud classification products, the Angular Signature Cloud Mask (ASCM), correctly identified the rippled area as being at the surface.

In this image pair, the view from MISR's most oblique backward-viewing camera is on the left, and the color-coded image on the right shows the results of the ASCM. The colors represent the level of certainty in the classification. Areas that were classed as cloudy with high confidence are white, and areas where the confidence was lower are yellow; dark blue shows confidently clear areas, while light blue indicates clear with lower confidence. The ASCM works particularly well at detecting clouds over snow and ice, but also works well over ocean and land. The rippled area on the surface which could have been mistaken for clouds are actually sastrugi -- long wavelike ridges of snow formed by the wind and found on the polar plains. Usually sastrugi are only several centimeters high and several meters apart, but large portions of East Antarctica are covered by mega-sastrugi ice fields, with dune-like features as high as four meters separated by two to five kilometers. The mega-sastrugi fields are a result of unusual snow accumulation and redistribution processes influenced by the prevailing winds and climate conditions. MISR imagery indicates that these mega sastrugi were stationary features between 2002 and 2004.

Being able to distinguish clouds from snow or ice-covered surfaces is important in order to adequately characterize the radiation balance of the polar regions. However, detecting clouds using spaceborne detectors over snow and ice surfaces is notoriously difficult, because the surface may often be as bright and as cold as the overlying clouds, and because polar atmospheric temperature inversions sometimes mean that clouds are warmer than the underlying snow or ice surface. The Angular Signature Cloud Mask (ASCM) was developed based on the Band-Differenced Angular Signature (BDAS) approach, introduced by Di Girolamo and Davies (1994) and updated for MISR application by Di Girolamo and Wilson (2003). BDAS uses both spectral and angular changes in reflectivity to distinguish clouds from the background, and the ASCM calculates the difference between the 446 and 866 nanometer reflectances at MISR's two most oblique cameras that view forward-scattered light. New land thresholds for the ASCM are planned for delivery later this year.

The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days views the entire globe between 82o north and 82o south latitude. This image area covers about 277 kilometers by 421 kilometers in the interior of the East Antarctic ice sheet. These data products were generated from a portion of the imagery acquired during Terra orbit 26584 and utilize data from within blocks 159 to 161 within World Reference System-2 path 63.

MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

2005-01-01

316

Enabling virtual wafer CD (WCD) using inverse pattern rendering (IPR) of mask CD-SEM images  

NASA Astrophysics Data System (ADS)

A wafer's printed CD error can be impacted by unaccounted mask making process variation. Unaccounted mask CD and/or corner rounding alters the intended drawn mask pattern contributing to a wafer's printed CD error. During OPC wafer calibration, average mask bias and corner rounding are accounted for in the OPC model, but random local mask making process variations or mask-to-mask variations can be difficult to account in such model calibration. Thus when a wafer's CD has error, it can be difficult to determine if the general root cause was due to mask or wafer or both. An in-line monitoring application has been developed to extract accurate mask CD and rendered mask polygon from collected mask CD-SEM images. Technical information will be presented on the challenges of accurately extracting information from SEM images. In particular, discussions include SEM image calibration, contour extraction, inverse pattern rendering, and general image processing to account for mask SEM aberrations (translation, rotation, & dilation), tool-to-tool variation, vendor-to-vendor variation, run-to-run variation, and dark/bright field pattern-to-pattern variation. After accurate mask SEM contours are obtained, lithographic simulations are performed on extracted polygon contours to determine the impact of mask variation on wafer CD. This paper will present detail information about the Inverse Pattern Rendering (IPR) capabilities developed for a virtual Wafer CD (WCD) application and its results, which is proven to achieved 0.5 nm accuracy across multiple critical layers from 28 nm to 40 nm nodes on multiple CD-SEM tools over multiple mask shop locations.

Dam, Thuc; Chen, Dongxue; Chang, Hsien-Min; Corcoran, Noel; Yu, Paul; Pang, Linyong; Chang, Chia-Wei; Lai, Rick; Chang, Peter; Tuo, Laurent

2011-11-01

317

Protein subcellular location pattern classification in cellular images using latent discriminative models  

PubMed Central

Motivation: Knowledge of the subcellular location of a protein is crucial for understanding its functions. The subcellular pattern of a protein is typically represented as the set of cellular components in which it is located, and an important task is to determine this set from microscope images. In this article, we address this classification problem using confocal immunofluorescence images from the Human Protein Atlas (HPA) project. The HPA contains images of cells stained for many proteins; each is also stained for three reference components, but there are many other components that are invisible. Given one such cell, the task is to classify the pattern type of the stained protein. We first randomly select local image regions within the cells, and then extract various carefully designed features from these regions. This region-based approach enables us to explicitly study the relationship between proteins and different cell components, as well as the interactions between these components. To achieve these two goals, we propose two discriminative models that extend logistic regression with structured latent variables. The first model allows the same protein pattern class to be expressed differently according to the underlying components in different regions. The second model further captures the spatial dependencies between the components within the same cell so that we can better infer these components. To learn these models, we propose a fast approximate algorithm for inference, and then use gradient-based methods to maximize the data likelihood. Results: In the experiments, we show that the proposed models help improve the classification accuracies on synthetic data and real cellular images. The best overall accuracy we report in this article for classifying 942 proteins into 13 classes of patterns is about 84.6%, which to our knowledge is the best so far. In addition, the dependencies learned are consistent with prior knowledge of cell organization. Availability: http://murphylab.web.cmu.edu/software/. Contact: Jeff.Schneider@cs.cmu.edu, murphy@cmu.edu PMID:22689776

Li, Jieyue; Xiong, Liang; Schneider, Jeff; Murphy, Robert F.

2012-01-01

318

Advanced Diagnostic Breast Cancer Imaging: Variation and Patterns of Care in Washington State  

PubMed Central

Introduction: Because receipt of breast imaging likely occurs in nonrandom patterns, selection bias is an important issue in studies that attempt to elucidate associations between imaging and breast cancer outcomes. The purpose of this study was to analyze use of advanced diagnostic imaging in a cohort of patients with breast cancer insured by commercial, managed care, and public health plans by demographic, health insurance, and clinical variables from 2002 to 2009. Methods: We identified women with breast cancer diagnoses from a Surveillance Epidemiology and End Results (SEER) registry whose data could be linked to claims from participating health plans. We examined imaging that occurred between cancer diagnosis and initiation of treatment and classified patients according to receipt of (1) mammography or ultrasound only; (2) breast magnetic resonance imaging (MRI); and (3) other advanced imaging (computed tomography [CT] of the chest, abdoment, and pelvis; positron emission tomography [PET]; or PET-CT). We used logistic regression to identify factors associated with receipt of breast MRI as well as other advanced imaging. Results: Commercial health plan, younger age, and later year of diagnosis were strongly associated with receipt of breast MRI and other advanced imaging. Women with prescription drug plans and those who had less comorbidities were more likely to have received breast MRI. Conclusion: Use of breast MRI and other advanced imaging is increasing among patients newly diagnosed with breast cancer; individual patient and insurance-related factors are associated with receipt of these imaging tests. Whether use of diagnostic advanced imaging affects outcomes such as re-excision, cancer recurrence, mortality rates, and costs of breast cancer treatment remains to be determined. PMID:23943885

Gold, Laura S.; Buist, Diana S.M.; Loggers, Elizabeth T.; Etzioni, Ruth; Kessler, Larry; Ramsey, Scott D.; Sullivan, Sean D.

2013-01-01

319

Parameter Estimation of Fossil Oysters from High Resolution 3D Point Cloud and Image Data  

NASA Astrophysics Data System (ADS)

A unique fossil oyster reef was excavated at Stetten in Lower Austria, which is also the highlight of the geo-edutainment park 'Fossilienwelt Weinviertel'. It provides the rare opportunity to study the Early Miocene flora and fauna of the Central Paratethys Sea. The site presents the world's largest fossil oyster biostrome formed about 16.5 million years ago in a tropical estuary of the Korneuburg Basin. About 15,000 up to 80-cm-long shells of Crassostrea gryphoides cover a 400 m2 large area. Our project 'Smart-Geology for the World's largest fossil oyster reef' combines methods of photogrammetry, geology and paleontology to document, evaluate and quantify the shell bed. This interdisciplinary approach will be applied to test hypotheses on the genesis of the taphocenosis (e.g.: tsunami versus major storm) and to reconstruct pre- and post-event processes. Hence, we are focusing on using visualization technologies from photogrammetry in geology and paleontology in order to develop new methods for automatic and objective evaluation of 3D point clouds. These will be studied on the basis of a very dense surface reconstruction of the oyster reef. 'Smart Geology', as extension of the classic discipline, exploits massive data, automatic interpretation, and visualization. Photogrammetry provides the tools for surface acquisition and objective, automated interpretation. We also want to stress the economic aspect of using automatic shape detection in paleontology, which saves manpower and increases efficiency during the monitoring and evaluation process. Currently, there are many well known algorithms for 3D shape detection of certain objects. We are using dense 3D laser scanning data from an instrument utilizing the phase shift measuring principle, which provides accurate geometrical basis < 3 mm. However, the situation is difficult in this multiple object scenario where more than 15,000 complete or fragmentary parts of an object with random orientation are found. The goal is to investigate if the application of state-of-the-art 3D digitizing, data processing, and visualization technologies support the interpretation of this paleontological site. The obtained 3D data (approx. 1 billion points at the respective area) is analyzed with respect to their 3D structure in order to derive geometrical information. The aim of this contribution is to segment the 3D point cloud of laser scanning data into meaningful regions representing particular objects. Geometric parameters (curvature, tangent plane orientation, local minimum and maximum, etc.) are derived for every 3D point of the point cloud. A set of features is computed in each point using different kernel sizes to define neighborhoods of different size. This provides information on convexity (outer surface), concavity (inner surface) and locally flat areas, which shall be further utilized in fitting model of Crassostrea-shells. In addition, digitizing is performed manually in order to obtain a representative set of reference data for the evaluation of the obtained results. For evaluating these results the reference data (length and orientation of specimen) is then compared to the automatically derived segments of the point cloud. The study is supported by the Austrian Science Fund (FWF P 25883-N29).

Djuricic, Ana; Harzhauser, Mathias; Dorninger, Peter; Nothegger, Clemens; Mandic, Oleg; Székely, Balázs; Molnár, Gábor; Pfeifer, Norbert

2014-05-01

320

Imaging spectroscopy diagnosis of internal electron temperature and density distributions of plasma cloud surrounding hydrogen pellet in the Large Helical Device  

SciTech Connect

To investigate the behavior of hydrogen pellet ablation, a novel method of high-speed imaging spectroscopy has been used in the Large Helical Device (LHD) for identifying the internal distribution of the electron density and temperature of the plasma cloud surrounding the pellet. This spectroscopic system consists of a five-branch fiberscope and a fast camera, with each objective lens having a different narrow-band optical filter for the hydrogen Balmer lines and the background continuum radiation. The electron density and temperature in the plasma cloud are obtained, with a spatial resolution of about 6 mm and a temporal resolution of 5 Multiplication-Sign 10{sup -5} s, from the intensity ratio measured through these filters. To verify the imaging, the average electron density and temperature also have been measured from the total emission by using a photodiode, showing that both density and temperature increase with time during the pellet ablation. The electron density distribution ranging from 10{sup 22} to 10{sup 24} m{sup -3} and the temperature distribution around 1 eV have been observed via imaging. The electron density and temperature of a 0.1 m plasma cloud are distributed along the magnetic field lines and a significant electron pressure forms in the plasma cloud for typical experimental conditions of the LHD.

Motojima, G.; Sakamoto, R.; Goto, M.; Matsuyama, A.; Yamada, H. [National Institute for Fusion Science, 322-6, Oroshi-cho, Toki-City, Gifu 509-5292 (Japan); Mishra, J. S. [Graduate University for Advanced Studies, 322-6, Oroshi-cho, Toki-City, Gifu 509-5292 (Japan)

2012-09-15

321

Influence of permittivity and electrical conductivity on image pattern of MRI.  

PubMed

In proton density-weighted (PDW) MR imaging, the patterns of signal intensity vary depending on the imaged material, and change with the flip angle (FA) applied to the imaged material. The correlation between the pre-determined FA and the actual FA applied to imaged objects was investigated using 4 types of phantoms having different dielectric properties. PDW images were acquired using the spin-echo (SE) method and different pre-determined FA. Dependency of the signal intensity distribution in the phantom on the pre-determined FA differed among phantoms: patterns for water and 0.402 w/w% saline solution phantoms changed with the pre-determined FA, whereas those for olive oil and 4.02 w/w% saline solution phantoms were barely affected by the pre-determined FA. Causes of these phenomena were considered to be the differences between the pre-determined FA and the actual FA among the phantoms; differences were also influenced by the positioning of the phantom. Our study showed that the actual FA in the phantom is greater than the pre-determined FA in high permittivity media, whereas it is reduced by an increased conductivity of the media. PMID:23694908

Harimoto, Takashi; Ohno, Seiichiro; Hattori, Kengo; Hirosue, Miyuki; Miyai, Masahiro; Shibuya, Koichi; Kuroda, Masahiro; Kanazawa, Susumu; Kato, Hirokazu

2013-01-01

322

Color treatment in endoscopic image classification using multi-scale local color vector patterns  

PubMed Central

In this work we propose a novel method to describe local texture properties within color images with the aim of automated classification of endoscopic images. In contrast to comparable Local Binary Patterns operator approaches, where the respective texture operator is almost always applied to each color channel separately, we construct a color vector field from an image. Based on this field the proposed operator computes the similarity between neighboring pixels. The resulting image descriptor is a compact 1D-histogram which we use for a classification using the k-nearest neighbors classifier. To show the usability of this operator we use it to classify magnification-endoscopic images according to the pit pattern classification scheme. Apart from that, we also show that compared to previously proposed operators we are not only able to get competitive classification results in our application scenario, but that the proposed operator is also able to outperform the other methods either in terms of speed, feature compactness, or both. PMID:21624846

Hafner, M.; Liedlgruber, M.; Uhl, A.; Vecsei, A.; Wrba, F.

2012-01-01

323

Recurrent uterine cancer after surgery: magnetic resonance imaging patterns and their changes after concomitant chemoradiation  

Microsoft Academic Search

Purpose  Our primary objective was to describe the magnetic resonance (MR) imaging patterns of recurrent uterine cancer after surgery\\u000a and their changes following concurrent chemoradiation. The secondary objective was to identify MR imaging predictors of outcome.\\u000a \\u000a \\u000a \\u000a Materials and methods  Twenty-two consecutive women with biopsy-proven recurrent uterine cancer after surgery (cervix 13 patients, endometrium nine\\u000a patients) were enrolled in this prospective study. Inclusion

R. Manfredi; S. Baltieri; A. Tognolini; R. Graziani; D. Smaniotto; N. Cellini; L. Bonomo

2008-01-01

324

Low temperature a-Si :H photodiodes and flexible image sensor arrays patterned by digital lithography  

NASA Astrophysics Data System (ADS)

Hydrogenated amorphous silicon-based image sensor arrays were fabricated on polyethylene naphthalate substrates, with photodiodes optimized for process temperatures of 150°C. An optimal i-layer thickness was determined to minimize carrier recombination and to maintain sufficient light absorption and acceptable leakage current. Patterning of the thin-film transistor backplane was accomplished using ink-jet printed etch masks. A flexible image sensor is demonstrated with 75dots/in. resolution over 180×180pixels and with sensitivity of 1.2pW/cm2.

Ng, Tse Nga; Lujan, Rene A.; Sambandan, Sanjiv; Street, Robert A.; Limb, Scott; Wong, William S.

2007-08-01

325

An investigation of time variations in a subtropical jet stream and the associated cloud patterns as shown by TIROS I  

E-print Network

. The effect of subsidence is evident at the northern end of the cross section and the jet front in the middle troposphere has become more pronounced. Note that the jet front is associated with the 325K potential temperature i. sopleth and extends... the surface. The association of the moist region at the. north end of. the cross section of Figure 47 with the new surface polar front is fairly obvious. As in previous cases the band of middle. and high level clouds was oriented along the south side...

Lester, Peter Francis

2012-06-07

326

Patterns of satellite-viewed, subtropical, jet-stream clouds in relation to the observed wind field  

E-print Network

Directed by: Dr. Robert A. Clark Satellite and rawinsonde data were analyzed for six cases of satellite-viewed, subtropical, jet-stresm clouds. Charts of maxi- mum wind and cross sections normal to the jet axis were analyzed. Mean cross sections were... forecasting of winds, turbulence, and sky condition in these areas. ACKNOWLEDGMENTS The author' s graduate program was made possible and sponsored by the United States Air Force. I wish to express my sincere thanks and appreciation to Dr. Robert A. Clark...

Vogt, Richard Joel

2012-06-07

327

Joint segmentation of images and scanned point cloud in large-scale street scenes with low-annotation cost.  

PubMed

We propose a novel method for the parsing of images and scanned point cloud in large-scale street environment. The proposed method significantly reduces the intensive labeling cost in previous works by automatically generating training data from the input data. The automatic generation of training data begins with the initialization of training data with weak priors in the street environment, followed by a filtering scheme to remove mislabeled training samples. We formulate the filtering as a binary labeling optimization problem over a conditional random filed that we call object graph, simultaneously integrating spatial smoothness preference and label consistency between 2D and 3D. Toward the final parsing, with the automatically generated training data, a CRF-based parsing method that integrates the coordination of image appearance and 3D geometry is adopted to perform the parsing of large-scale street scenes. The proposed approach is evaluated on city-scale Google Street View data, with an encouraging parsing performance demonstrated. PMID:25148662

Zhang, Honghui; Wang, Jinglu; Fang, Tian; Quan, Long

2014-11-01

328

Imaging of four planetary nebulae in the Magellanic Clouds using the Hubble Space Telescope Faint Object Camera  

NASA Technical Reports Server (NTRS)

Using the Faint Object Camera on-board the Hubble Space Telescope, we have obtained images of four planetary nebulae (PNe) in the Magellanic Clouds, namely N2 and N5 in the SMC and N66 and N201 in the LMC. Each nebula was imaged through two narrow-band filters isolating forbidden O III 5007 and H-beta, for a nominal exposure time of 1000 s in each filter. In forbidden O III, SMC N5 shows a circular ring structure, with a peak-to-peak diameter of 0.26 arcsec and a FWHM of 0.35 arcsec while SMC N2 shows an elliptical ring structure with a peak-to-peak diameter of 0.26 x 0.21. The expansion ages corresponding to the observed structures in SMC N2 and N5 are of the order of 3000 yr. LMC N201 is very compact, with a FWHM of 0.2 arcsec in H-beta. The Type I PN LMC N66 is a multipolar nebula, with the brightest part having an extent of about 2 arcsec and with fainter structures extending over 4 arcsec.

Blades, J. C.; Barlow, M. J.; Albrecht, R.; Barbieri, C.; Boksenberg, A.; Crane, P.; Deharveng, J. M.; Disney, M. J.; Jakobsen, P.; Kamperman, T. M.

1992-01-01

329

The correlation between magnetic resonance imaging and ultrastructural patterns of brown adipose tissue.  

PubMed

The present paper reports on magnetic resonance imaging (MRI) at high spatial resolution of the brown adipose tissue (BAT) in laboratory rodents, in comparison with light and electron microscopy findings. Our aim was to assess whether MRI correlates with the expected ultrastructural differences between newborn and adult BAT. The study was performed on the cervical and the interscapular BAT deposits by means of a nuclear magnetic resonance (NMR)-spectrometer equipped with a high resolution imaging system. Ultrastructural examination of BAT at different ages showed three different patterns of adipocyte ultrastructure in BAT which were associated with different MRI patterns. In BAT, MRI identifies the prevalent type of adipocyte in the tissue providing information consistent with ultrastructural results. Results presented here show that MRI represents a precise and reliable tool to investigate the morphology of tissues in living animals. The safe, non-invasive MRI technique represents a very useful tool in morphological research. PMID:2036625

Osculati, F; Sbarbati, A; Leclercq, F; Zancanaro, C; Accordini, C; Antonakis, K; Boicelli, A; Cinti, S

1991-01-01

330

Cloud Fragmentation and Proplyd-like Features in H II Regions Imaged by the Hubble Space Telescope  

NASA Astrophysics Data System (ADS)

We have analyzed Hubble Space Telescope ACS and WFPC2 new and archival images of eight H II regions to look for new protoplanetary disks (proplyds) similar to those found in the Orion Nebula. We find a wealth of features similar in size (although many are larger) to the bright cusps around the Orion Nebula proplyds. None of them, however, contains a definitive central star. From this, we deduce that the new cusps may not be proplyds but instead fragments of molecular cloud material. Out of all the features found in the eight H II regions examined, only one, an apparent edge-on silhouette in M17, may have a central star. This feature might join the small number of bona fide proplyds found outside the Orion Nebula, in M8, M20, and possibly M16. In line with the results found recently by Smith et al., the paucity of proplyds outside the Orion Nebula can be explained by their transient nature, as well as by the specific environmental conditions under which they can be observed. Several fragments are seen as dark silhouettes against a bright background. We have reanalyzed those found in IC 2944 by Reipurth et al. and found new, similar ones in M16. None of these fragments contains a central star, and we exclude the possibility that they are disks. Reipurth et al. concluded that the IC 2944 silhouettes are not star forming. We argue here that their assumption of a constant optical depth for these fragments is not physical and that it is more likely that these fragments are star forming, a condition that is supported, although not proved, by their shapes and distributions. The process of cloud fragmentation and photoevaporation produces a large number of small fragments, while the size hierarchy expected in a photoevaporative environment would not favor small fragments. The size distributions observed will constrain any future theories of cloud fragmentation. One bright microjet candidate is found in M17, protruding from a large, limb-brightened fragment. A second, larger, jetlike feature, similar in shape and size to a Herbig-Haro jet, is found in Pismis 24. No central star appears to be associated with either of these jet candidates. Based on observations made with the NASA/ESA Hubble Space Telescope obtained at the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555.

De Marco, Orsola; O'Dell, C. R.; Gelfond, Pamela; Rubin, R. H.; Glover, S. C. O.

2006-05-01

331

Constraining mass-diameter relations from hydrometeor images and cloud radar reflectivities in tropical continental and oceanic convective anvils  

NASA Astrophysics Data System (ADS)

In this study the density of hydrometeors in tropical clouds is derived from a combined analysis of particle images from 2-D-array probes and associated reflectivities measured with a Doppler cloud radar on the same research aircraft. The mass-diameter m(D) relationship is expressed as a power law with two unknown coefficients (pre-factor, exponent) that need to be constrained from complementary information on hydrometeors, where absolute ice density measurement methods do not apply. Here, at first an extended theoretical study of numerous hydrometeor shapes simulated in 3-D and arbitrarily projected on a 2-D plane allowed to constrain the temporal evolution of the exponent of the mass-diameter relationship with that of the exponent of the surface-diameter relationship that is measured by the 2-D-array probes. The pre-factor is then constrained from theoretical simulations of the radar reflectivities matching the measured reflectivities along the aircraft trajectory. The study has been performed as part of the Megha-Tropiques satellite project, where two types of mesoscale convective systems (MCS) have been investigated: (i) above the African Continent and (ii) above the Indian Ocean. In general, both mass-diameter coefficients (pre-factor and exponent) decrease with decreasing temperature, the decrease is more pronounced for oceanic MCS. The condensed water contents (CWC) calculated from particle size distributions (PSD) and m(D) also decrease with altitude while the concentrations of the hydrometeors increase with altitude. The calculated values of CWC are largest for continental MCS.

Fontaine, E.; Schwarzenboeck, A.; Delanoë, J.; Wobrock, W.; Leroy, D.; Dupuy, R.; Protat, A.

2014-01-01

332

Pattern of cortical reorganization in amyotrophic lateral sclerosis: a functional magnetic resonance imaging study  

Microsoft Academic Search

Depending on individual lesion location and extent, reorganization of the human motor system has been observed with a high\\u000a interindividual variability. In addition, variability of forces exerted, of motor effort, and of movement strategies complicates\\u000a the interpretation of functional imaging studies. We hypothesize that a general pattern of reorganization can be identified\\u000a if a homogeneous patient population is chosen and

Carsten Konrad; Henning Henningsen; Janbernd Bremer; Brian Mock; Michael Deppe; Christiane Buchinger; Pat Turski; Stefan Knecht; Benjamin Brooks

2002-01-01

333

Strain distributions made visible with image-shearing speckle pattern interferometry  

Microsoft Academic Search

The measurement of in-plane strain with image-shearing speckle pattern interferometry has so far been impeded by the lack of an efficient method for suppressing the out-of-plane displacement derivative. This paper presents a simple optical set-up with three light sources arranged in a particular symmetry and an associated procedure which allows accurate isolation of all six displacement derivatives which can contribute

Hubert A. Aebischer; Stephan Waldner

1997-01-01

334

Scattered Brain Infarct Pattern on Diffusion-Weighted Magnetic Resonance Imaging in Patients with Acute Ischemic Stroke  

Microsoft Academic Search

Background and Purpose: Infarct patterns on brain imaging contribute to the etiologic classification of ischemic stroke. However, the association of specific subtypes of infarcts and etiologic mechanisms is often weak, and acute lesions are frequently missed on initial computed tomography (CT). Diffusion-weighted imaging (DWI) is superior in visualizing acute ischemic lesions as compared to CT and conventional magnetic resonance imaging

Hans-Christian Koennecke; Johannes Bernarding; Jürgen Braun; Andreas Faulstich; Chris Hofmeister; Roland Nohr; Stefanie Leistner; Peter Marx

2001-01-01

335

Wave Clouds over the Arabian Sea  

NASA Technical Reports Server (NTRS)

Like a massive, ethereal bird gliding into the Persian Gulf, a large cluster of wave clouds spans the Arabian Sea from Oman to India. This cloud formation is likely an undular bore, which is created in the interaction between the cool, dry air in a low-pressure system with a stable layer of warm, moist air. In this case, a low-pressure system probably sits over the Arabian Peninsula, the Gulf of Oman, and Iran and Pakistan. The strong winds generated by the low-pressure system are kicking up clouds of dust from Iran and Pakistan, and, to a lesser degree, Oman. The low-pressure system is also pushing air south-southeast, and this south-moving wave of displaced air pushes ahead of the low-pressure system like a mound of water moving ahead of a boat in calm water. The wave of cool, dry air pushes forward until it meets the wall of warm, moist air that blankets the Arabian Sea. When the two air masses clash, the cool air pushes the warm air up. The warm air rises, cools at the peak of the wave, falls again, and then rises to a slightly lower peak, and so forth, until the wave dissipates. Clouds form at the high-altitude peaks of the waves, with the most defined cloud at the front of the group, where the initial wave formed, followed by increasingly less-defined lines of cloud. The air that moves in front of the low-pressure system does not push forward in a uniform wall; instead it pushes forward in a ragged band, with one part racing ahead of another, like a line of crew racers on a river. Because the air is not uniform, there are small, interacting arcs of waves within the larger band of clouds. Undular bores are rare and hard to predict. This particular undular bore formed over the Arabian Sea on May 8, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Aqua satellite captured this photo-like image. Typical undular bore patterns might display one or two rows of clouds. With more than thirty waves of clouds, this cloud pattern is unusually large. Some secondary air mass--a jet of warm tropical air, perhaps--cuts across the center of the wave pattern, creating the long vertical cloud that makes the formation resemble a bird. The undulating air also appears to have roughened the surface of the ocean. Bands of light and dark water mimic the wave pattern near the shore of Oman. Rough water disperses light, creating the dark bands, while calm water is brighter. This wave pattern is probably happening across the Arabian Sea, but it is only visible on the left side of the image because of the angle of the light reflecting from the water. In this area, sunlight reflecting off the water directly to the MODIS sensor turns the water's surface into a silvery mirror. It is only in these areas of sunglint that the surface roughness created by the undular bore is visible. The large image provided above is at MODIS' maximum resolution of 250 meters per pixel. The image is available in additional resolutions from the MODIS Rapid Response System. For a different view of an undular bore, see LIDAR Profile of a Passing Cold Front on the Earth Science Picture of the Day, a service of the Universities Space Research Association sponsored by NASA Goddard Space Flight Center.

2007-01-01

336

Near-field imaging of neurotransmitter release and uptake in patterned neuron networks  

NASA Astrophysics Data System (ADS)

A SNOAM system is capable of obtaining simultaneous topographic and optical images with a resolution beyond than the diffraction limit of far field optical imaging. Fluorescence tagging combined with optical resolutions of better than 100nm allow us to detect structures not possible with conventional microscopes. Also in contrast with electron microscopy SNOAM has the ability to look at biological structures in the liquid medium. Presently there is much interest in understanding the processes that lead to LTP in neuron synapses. LTP is widely associated with memory function in neurons. Hence, better understanding will lead to advances in medicine, as well as neuron-based memory and processing devices. Better understanding is also crucial to the development of neuron-electronic interfaces. In this research, neuron networks are grown on a patterned polylysine substrate. Polylysine is patterned using micro lithographic techniques. Neurons are extracted from the hippocampus of chick embryos, and are then grown on this pattern under standard sterile incubating conditions. The neurons are stimulated to release the neurotransmitter glutamate. The glutamate is then fluorescently imaged with Amplex-red SNOAM.

Degenaar, Patrick; Murakami, Yuji; Yokoyama, Kenji; Tamiya, Eiichi; Le Pioufle, Bruno; Fujita, Yiroyuki

2000-04-01

337

Image processing and 3D visualization in the interpretation of patterned injury of the skin  

NASA Astrophysics Data System (ADS)

The use of image processing is becoming increasingly important in the evaluation of violent crime. While much work has been done in the use of these techniques for forensic purposes outside of forensic pathology, its use in the pathologic examination of wounding has been limited. We are investigating the use of image processing in the analysis of patterned injuries and tissue damage. Our interests are currently concentrated on 1) the use of image processing techniques to aid the investigator in observing and evaluating patterned injuries in photographs, 2) measurement of the 3D shape characteristics of surface lesions, and 3) correlation of patterned injuries with deep tissue injury as a problem in 3D visualization. We are beginning investigations in data-acquisition problems for performing 3D scene reconstructions from the pathology perspective of correlating tissue injury to scene features and trace evidence localization. Our primary tool for correlation of surface injuries with deep tissue injuries has been the comparison of processed surface injury photographs with 3D reconstructions from antemortem CT and MRI data. We have developed a prototype robot for the acquisition of 3D wound and scene data.

Oliver, William R.; Altschuler, Bruce R.

1995-09-01

338

Landsat 7 - First Cloud-free Image of Yellowstone National Park  

NASA Technical Reports Server (NTRS)

This image of Yellowstone Lake, in the center of Yellowstone National Park, was taken by Landsat 7 on July 13, 1999. Bands 5 (1.65um),4 (.825um), and 2 (.565um) were used for red, green, and blue, respectively. Water appears blue/black, snow light blue, mature forest red/green, young forest pink, and grass and fields appear light green. Southwest of the lake is young forest that is growing in the wake of the widespread fires of 1988. For more information, see: Landsat 7 Fact Sheet Landsat 7 in Mission Control Image by Rich Irish, NASA GSFC

2002-01-01

339

Feasibility study on Compton imaging for visualization of flow patterns using radiotracers  

NASA Astrophysics Data System (ADS)

The radiotracer technique could be used in studies on multiphase flow systems by three-dimensional visualization of flow patterns, and, relatedly, there have been attempts to develop an industrial-purpose single photon emission computed tomography (SPECT) system. Compton cameras also have a great potential for industrial applications, due specifically to their inherent three-dimensional imaging capability, multi-tracing capability, and higher imaging sensitivity than imaging devices based on mechanical collimation. In the present study, the feasibility of Compton imaging for visualization of detailed flow patterns was determined using a Geant4 Monte Carlo simulation toolkit. The Compton camera considered is a double-scattering type consisting of three gamma-ray detectors: two double-sided silicon strip detectors (DSSDs) as scatterer detectors and one NaI(Tl) scintillation detector as an absorber detector. The results showed that the three-dimensional source distributions can be determined with the Compton camera under various source conditions, including a point source at the center, and two cylinderial volume sources of different dimensions or energies.

Seo, H.; Park, J. H.; Park, J. G.; Ushakov, A.; Kim, C. H.; Lee, J. H.; Lee, C. S.; Lee, J. S.

2011-01-01

340

Pattern recognition applied to infrared images for early alerts in fog  

NASA Astrophysics Data System (ADS)

Fog conditions are the cause of severe car accidents in western countries because of the poor induced visibility. Its forecast and intensity are still very difficult to predict by weather services. Infrared cameras allow to detect and to identify objects in fog while visibility is too low for eye detection. Over the past years, the implementation of cost effective infrared cameras on some vehicles has enabled such detection. On the other hand pattern recognition algorithms based on Canny filters and Hough transformation are a common tool applied to images. Based on these facts, a joint research program between IFSTTAR and Cerema has been developed to study the benefit of infrared images obtained in a fog tunnel during its natural dissipation. Pattern recognition algorithms have been applied, specifically on road signs which shape is usually associated to a specific meaning (circular for a speed limit, triangle for an alert, …). It has been shown that road signs were detected early enough in images, with respect to images in the visible spectrum, to trigger useful alerts for Advanced Driver Assistance Systems.

Boucher, Vincent; Marchetti, Mario; Dumoulin, Jean; Cord, Aurélien

2014-09-01

341

Pattern recognition system invariant to rotation and scale to identify color images  

NASA Astrophysics Data System (ADS)

This work presents a pattern recognition digital system based on nonlinear correlations. The correlation peak values given by the system were analyzed by the peak-to-correlation energy (PCE) metric to determine the optimal value of the non-linear coefficient kin the k-law. The system was tested with 18 different color images of butterflies; each image was rotated from 0° to 180° with increments of 1° and scaled ±25% with increments of 1% and to take advantage of the color property of the images the RGB model was employed. The boxplot statistical analysis of the mean with ±2*EE (standard errors) for the PCE values set that the system invariant to rotation and scale has a confidence level at least of 95.4%.

Coronel-Beltrán, Angel

2014-10-01

342

Cloudshine: New Light on Dark Clouds  

E-print Network

We present new deep near-infrared images of dark clouds in the Perseus molecular complex. These images show beautiful extended emission which we model as scattered ambient starlight and name ``cloudshine''. The brightness and color variation of cloudshine complicates the production of extinction maps, the best tracer of column density in clouds. However, since the profile of reflected light is essentially a function of mass distribution, cloudshine provides a new way to study the structure of dark clouds. Previous work has used optical scattered light to study the density profile of tenuous clouds; extending this technique into the infrared provides a high-resolution view into the interiors of very dense clouds, bypassing the complexities of using thermal dust emission, which is biased by grain temperature, or molecular tracers, which have complicated depletion patterns. As new wide-field infrared cameras are used to study star-forming regions at greater depth, cloudshine will be widely observed and should be seen as a new high-resolution tool, rather than an inconvenience.

Jonathan B. Foster; Alyssa A. Goodman

2005-10-20

343

Analysis of dual polarization images of precipitating clouds collected by the COSMO SkyMed constellation  

NASA Astrophysics Data System (ADS)

Currently, several satellite missions are employing X-band synthetic aperture radars (SAR) with polarimetric capabilities. In images collected over land by X-band SAR, precipitation results mainly in evident attenuation of the surface returns. Effects of precipitation in polarimetric SAR images and how to exploit them for precipitation studies are emerging topics of interest. This paper investigates polarimetric signatures of precipitation in images collected by the X-band SARs of the Italian Space Agency COSMO SkyMed constellation using the HH-VV alternate polarimetric mode. Analyzed images were collected in 2010 when the constellation was composed of three satellites and operated in the “tandem like” interferometric configuration, which allowed acquisition of the same scene with the same viewing geometry and a minimum decorrelation time of one day. Observations collected in Piedmont (Italy) and Tampa Bay (Florida, US) have been analyzed along with coincident observations collected by operational weather radars, used to reconstruct the component of SAR returns due to precipitation at horizontal and vertical polarization states. Different techniques are used depending on the different characteristics of terrestrial radars. SAR observations reconstructed from terrestrial measurements are in fairly good agreement with actual SAR observations. Results confirm that the attenuation signature in SAR images collected over land is particularly pronounced in the presence of precipitation cells and can be related to the radar reflectivity integrated along the same path. The difference between copolar HH and VV power measurements reveals a differential attenuation due to anisotropy of precipitation, whose range is limited when the SAR incidence angle is low. A specific feature observed in the CosmoSkyMed alternate polarization implementation is the presence of the scalloping effect, a periodic effect along the azimuth direction that cannot always be removed by standard de-scalloping techniques. Amplitude of scalloping between the two polarizations can reach a couple of decibels, close to the maximum range of differential path integrated attenuation.

Baldini, Luca; Roberto, Nicoletta; Gorgucci, Eugenio; Fritz, Jason; Chandrasekar, V.

2014-07-01

344

Photoionization modelling based on HST images of Magellanic Cloud planetary nebulae - I. SMCN2 and SMCN5  

NASA Astrophysics Data System (ADS)

We construct fully self-consistent, detailed photoionization models for two planetary nebulae (PNe) in the Small Magellanic Cloud (SMC), namely SMC N 2 and SMC N 5, to fit optical and UV spectrophotometric observations as well as HST Faint Object Camera (FOC) narrow-band images taken in the light of H?. The derived density structure shows that both PNe have a central cavity surrounded by a shell of decreasing density described by a parabolic curve. For both nebulae, our models fail to reproduce the HST images taken in the light of the [OIII]lambda5007 line, in the sense that the observed [OIII]lambda5007 surface brightness decreases more slowly outside the peak emission than predicted. An effective temperature of T_eff=111500K, a stellar surface gravity of logg=5.45 and a luminosity of L_*=8430L_solar are derived for the central star of SMC N2; similarly T_eff=137500K, logg=6.0 and L_*=5850L_solar are derived for SMC N 5. SMC N 2 is optically thin and has a total nebular mass (H plus He) of 0.180 M_solar, while SMC N 5 is optically thick and has an ionized gas mass of 0.194 M_solar. Using the H-burning SMC metal abundance (Z=0.004) evolutionary tracks calculated by Vassiliadis & Wood, core masses of 0.674M_solar and 0.649M_solar are derived for SMC N 2 and SMC N 5, respectively. Similarly, from the He-burning evolutionary tracks of Vassiliadis & Wood for progenitor stars of mean LMC heavy-element abundance (Z=0.008), we find M_c=0.695 and 0.675M_solar for SMC N 2 and SMC N 5, respectively. We find that H? images are needed if one is to derive accurate stellar luminosities directly from photoionization modelling. However, in the absence of an H? image, photoionization models based on [OIII] images (and nebular line intensities) yield accurate values of T_eff and logg, which in turn allow reliable stellar masses and luminosities to be derived from a comparison with theoretical evolutionary tracks. We show that the correct nebular ionized mass can be deduced from the nebular H? flux, provided the mean nebular density given by the CIII]lambda1909/lambda1907 ratio is also known.

Liu, X.-W.; Barlow, M. J.; Blades, J. C.; Osmer, S.; Clegg, R. E. S.

1995-09-01

345

What is a Cloud?  

NASA Astrophysics Data System (ADS)

There are multiple factors that cause disagreements between differing methods using differing instruments to infer cloud amounts. But along with these issues is a fundamental concern that has permeated all comparisons and supersedes such questions as what are the uncertainty estimates of a given retrieval. To wit: what is a cloud? How can uncertainty of a cloud amount measurement be determined when there is no absolute 'truth' on what defines a cloud, as opposed to cloud-free? Recent research comparing a decade of surface- and satellite-based retrievals of cloud amount for the ARM Southern Great Plains site shows significant disagreements. While Total Sky Imager 100-degree FOV, Shortwave (SW) Radiative Flux Analysis, GOES satellite and PATMOS-x satellite amounts agree relatively well, ISCCP satellite and ARSCL time-series cloud amounts are significantly greater, 15% (ISCCP) and 8% (ARSCL) larger in average diurnal variations. In both cases, it appears that optically thin high ice is counted as 'cloud' in ARSCL and ISCCP that is not categorized as cloud by all the others. Additionally, cloud amounts from three methods (ISCCP, ARSCL, and GOES) show an overall increase of 8%-10% in the annually averaged cloud fractions from 1998 to 2009, while those from the other three (TSI, SWFA, PATMOS-x) show little trend for this period. So one wonders: are cloud amounts increasing or not over this period? The SW Flux Analysis used sky imager retrievals as 'truth' in development of the methodology (Long et al, 2006a), where sky imagery itself used human observations as the model (Long et al., 2006b). Min et al. (2008) then used SW Flux Analysis retrievals as 'truth' to develop an MFRSR-based spectral SW retrieval method. Dupont et al. (2008) show that the SW-based retrievals allow up to a visible optical depth of 0.15 (95% of occurrences) under the 'clear-sky' category which primarily consists of sub-visual cirrus, which by ancestry applies to spectral SW, sky imager and human observations as well. This defines what we label the 'traditional' definition of 'what is a cloud' that has produced the long records based on human observations. But we submit that declaring 'cloud amount' by some methodology is not sufficient to be scientifically useful, but also a physical value of the cloud/clear delimiting factor used to detect what is a cloud must also be given. Perhaps visible optical depth might serve as a common variable to denote various retrievals clear/cloud limit, but some common variable needs to be agreed upon else discussions of quantifying 'uncertainty' is putting the cart before the horse. We will present examples and discussion of all the above.

Long, C. N.; Wu, W.

2013-12-01

346

Improved MSG-SEVIRI Images Cloud Masking and Evaluation of its Impact on the Fire Detection Methods  

Microsoft Academic Search

One of the most important factors responsible of the fire-detection algorithms fail is represented by the inaccurate cloud detection methods. In fact, the cloud-contaminated pixels are often associated with false fire pixel because of the brightness temperature increase in the mid-infrared channel. On the other hand an incorrect cloud masking could hide a real fire pixel, especially at the borders

Enrico Cadau; Giovanni Laneve

2008-01-01

347

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns  

NASA Technical Reports Server (NTRS)

A technique, associated system and program code, for retrieving depth information about at least one surface of an object, such as an anatomical feature. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the anatomical feature; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

2010-01-01

348

System and technique for retrieving depth information about a surface by projecting a composite image of modulated light patterns  

NASA Technical Reports Server (NTRS)

A technique, associated system and program code, for retrieving depth information about at least one surface of an object. Core features include: projecting a composite image comprising a plurality of modulated structured light patterns, at the object; capturing an image reflected from the surface; and recovering pattern information from the reflected image, for each of the modulated structured light patterns. Pattern information is preferably recovered for each modulated structured light pattern used to create the composite, by performing a demodulation of the reflected image. Reconstruction of the surface can be accomplished by using depth information from the recovered patterns to produce a depth map/mapping thereof. Each signal waveform used for the modulation of a respective structured light pattern, is distinct from each of the other signal waveforms used for the modulation of other structured light patterns of a composite image; these signal waveforms may be selected from suitable types in any combination of distinct signal waveforms, provided the waveforms used are uncorrelated with respect to each other. The depth map/mapping to be utilized in a host of applications, for example: displaying a 3-D view of the object; virtual reality user-interaction interface with a computerized device; face--or other animal feature or inanimate object--recognition and comparison techniques for security or identification purposes; and 3-D video teleconferencing/telecollaboration.

Hassebrook, Laurence G. (Inventor); Lau, Daniel L. (Inventor); Guan, Chun (Inventor)

2008-01-01

349

Stratus cloud structure from MM-radar transects and satellite images: scaling properties and artifact detection with semi-discrete wavelet analysis  

SciTech Connect

Spatial and/or temporal variabilities of clouds is of paramount importance for at least two in tensely researched sub-problems in global and regional climate modeling: (1) cloud-radiation interaction where correlations can trigger 3D radiative transfer effects; and (2) dynamical cloud modeling where the goal is to realistically reproduce the said correlations. We propose wavelets as a simple yet powerful way of quantifying cloud variability. More precisely, we use 'semi-discrete' wavelet transforms which, at least in the present statistical applications, have advantages over both its continuous and discrete counterparts found in the bulk of the wavelet literature. With the particular choice of normalization we adopt, the scale-dependence of the variance of the wavelet coefficients (i.e,, the wavelet energy spectrum) is always a better discriminator of transition from 'stationary' to 'nonstationary' behavior than conventional methods based on auto-correlation analysis, second-order structure function (a.k.a. the semi-variogram), or Fourier analysis. Indeed, the classic statistics go at best from monotonically scale- or wavenumber-dependent to flat at such a transition; by contrast, the wavelet spectrum changes the sign of its derivative with respect to scale. We apply 1D and 2D semi-discrete wavelet transforms to remote sensing data on cloud structure from two sources: (1) an upward-looking milli-meter cloud radar (MMCR) at DOE's climate observation site in Oklahoma deployed as part of the Atmospheric Radiation Measurement (ARM) Progrm; and (2) DOE's Multispectral Thermal Imager (MTI), a high-resolution space-borne instrument in sunsynchronous orbit that is described in sufficient detail for our present purposes by Weber et al. (1999). For each type of data, we have at least one theoretical prediction - with empirical validation already in existence - for a power-law relation for wavelet statistics with respect to scale. This is what is expected in physical (i.e., finite scaling range) fractal phenomena. In particular, we find long-range correlations in cloud structure coming from the important nonstationary regime. More surprisingly, we also uncover artifacts the data that are traceable either to instrumental noise (in the satellite data) or to smoothing assumptions (in the MMCR data processing). Finally, we discuss the potentially damaging ramifications the smoothing artifact can have on both cloud-radiation and cloud-modeling studies using MMCR data.

Davis, A. B. (Anthony B.); Petrov, N. P. (Nikola P.); Clothiaux, E. E. (Eugene E.); Marshak, A. (Alexander)

2002-01-01

350

Study of Aggregation Errors of the MODIS Landcover Image Using Analytical Equations and Spatial Pattern Metrics  

NASA Astrophysics Data System (ADS)

The scale of a study is an interaction of resolution (grain) and extent. Domians of scale appear to exist in which a relationship established at a particular scale may be reliably extrapolated at similar scales, but may break down when applied at very different scales. Pattern assessment based upon remote sensing data can therefore be considered as a hierarchical process, involving structural measurements at various scales. Spatial aggregation of data is required because patterns (and processes) have to be studied at the exact scale, and because high resolution data requires more processing and storage capacity. Data scale can be adjusted by aggregation of sub-pixels into pixels that represent a larger actual area, resulting in a smaller data set. Generally, the majority rule is applied to aggregate data, in which the pixel is assigned to the class represented by a majority of sub-pixels. The reliability of image analysis is assessed by analyzing the errors present in spatial data as the result of aggregation. Two main features are focused on: landcover class area and landcover pattern. Rare land cover types are lost when grain becomes coarser. Patchy arrangements dissappear more rapidly with decreasing resolution than contagious ones. Problems with grain arise when spatial elements at the sub-pixel level are scattered and are as small or smaller than the pixel. The spatial structure of the data sets at different scale (aggregation) levels is analyzed using patch statistics (area, perimeter, shape) and by calculation of pattern metrics (e.g. contiguity, clustering, class area evenness). Next to pattern analysis, analytical equations and relationships are developed to quantify aggregation effects. This will include the consideration of aggregation procedures different from the majority rule. Because the change -and the concomitant loss- of information with change of resolution is determined by the aggregation rule, insights provided by these analytical equations allows alternative aggregation schemes to be evaluated. The study is executed using aggregated images generated from the MODIS landcover image representing North America (original resolution 1 km) and containing 18 landcover classes (15 biomes, urban and built-up, water bodies, and open space related to image projection).

Bogaert, J. M.; Bogaert, J. M.; Tian, Y.; Myneni, R. B.

2001-12-01

351

Determining the optimal age for recording the retinal vascular pattern image of lambs.  

PubMed

Newborn Ripollesa lambs (n = 143) were used to assess the optimal age at which the vascular pattern of the retina can be used as a reference for identification and traceability. Retinal images from both eyes were recorded from birth to yearling (d 1, 8, 30, 82, 180, and 388 of age) in duplicate (2,534 images) using a digital camera specially designed for livestock (Optibrand, Fort Collins, CO). Intra- and inter-age image comparisons (9,316 pairs of images) were carried out, and matching score (MS) was used as the exclusion criterion of lamb identity (MS <70). Retinal images were used for verifying the identity of live lambs of 4 Spanish commercial categories: milk-fed lambs (MF; "lechal," 1 mo of age and <12 kg of BW, n = 136); light fattened lambs (LF; "recental," 3 mo of age and ~25 kg of BW, n = 134); recruited replacement lambs (RR; "ovino mayor," 6 mo of age and ~35 kg of BW, n = 59); and yearling replacement lambs (YR; >12 mo of age and ~50 kg of BW, n = 25). Values of MS were treated with a model based on the 1-inflated bivariate beta distribution, and treated data were compared by using a likelihood ratio test. Intra-age image comparisons showed that average MS and percentage of images with MS ?70 increased (P < 0.05) with lamb age from d 1 to 82 (81.0 ± 1.0 to 95.9 ± 0.4, and 75.8 to 100%, respectively) and reached a plateau thereafter. Inter-age retinal image comparisons for MF lambs at 30 d showed that the percentage of images with MS ?70 was greater when reference images at 8 d were used instead of 1-d images (94.8 vs. 87.4%, respectively; P < 0.05). In LF lambs, 30-d retinal images matched better than those at 8 d of age (99.6 vs. 93.6%, respectively; P < 0.05). Regarding RR and YR lambs, the 82-d images allowed the confirmation of 100% lamb identity, whereas 8-d images showed a smaller (P < 0.05) percentage of matching (87.9 and 89.8%, respectively, for RR and YR lambs; P > 0.05); no differences were detected for 30-d images (97.4 and 98.0%, respectively, for RR and YR lambs; P > 0.05). Total percentage of matching was achieved when images were obtained from older lambs (180 and 388 d). In conclusion, retinal imaging was a useful tool for verifying the identity and auditing the traceability of live lambs from suckling to yearling. Matching scores were satisfactory when the reference retinal images were obtained from 1-mo-old or older lambs. PMID:22064738

Rojas-Olivares, M A; Caja, G; Carné, S; Salama, A A K; Adell, N; Puig, P

2012-03-01

352

Quantitative planar imaging with technetium-99m methoxyisobutyl isonitrile: Comparison of uptake patterns with thallium-201  

SciTech Connect

To compare the myocardial uptake pattern of 99mTc-labeled methoxyisobutyl isonitrile (( 99mTc) MIBI) and 201TI, planar scintigraphy were performed in both patients with documented coronary artery disease and subjects with a low likelihood of disease. Quantitative analysis was employed using a standard interpolative background subtraction algorithm and a new algorithm modified to better accommodate for the differences in extracardiac activity seen with (99mTc)MIBI rest images. Among patients with coronary artery disease, the standard algorithm yielded no significant difference in relative defect magnitude between (99mTc)MIBI and 201TI on stress scintigrams (p = 0.48), although the magnitude of (99mTc)MIBI defects was greater on resting images (p = 0.02). When the modified algorithm was employed, defect magnitude was similar for both stress (p = 0.91) and rest (p = 0.20) images. Normal segmental uptake ratios derived from a comparison of contralateral segments (e.g., septal:posterolateral) in the low likelihood patients were similar for both (99mTc)MIBI and 201TI. Thus, modification of the standard interpolative background subtraction algorithm is necessary for quantitative planar (99mTc)MIBI perfusion imaging. When appropriate background subtraction is employed, myocardial uptake and quantitative defect magnitude of (99mTc)MIBI and 201TI planar images are similar.

Sinusas, A.J.; Beller, G.A.; Smith, W.H.; Vinson, E.L.; Brookeman, V.; Watson, D.D. (Univ. of Virginia Health Sciences Center, Charlottesville (USA))

1989-09-01

353

Spatiotemporal relations of primary sensorimotor and secondary motor activation patterns mapped by NIR imaging  

PubMed Central

Functional near infrared (fNIR) imaging was used to identify spatiotemporal relations between spatially distinct cortical regions activated during various hand and arm motion protocols. Imaging was performed over a field of view (FOV, 12 x 8.4 cm) including the secondary motor, primary sensorimotor, and the posterior parietal cortices over a single brain hemisphere. This is a more extended FOV than typically used in current fNIR studies. Three subjects performed four motor tasks that induced activation over this extended FOV. The tasks included card flipping (pronation and supination) that, to our knowledge, has not been performed in previous functional magnetic resonance imaging (fMRI) or fNIR studies. An earlier rise and a longer duration of the hemodynamic activation response were found in tasks requiring increased physical or mental effort. Additionally, analysis of activation images by cluster component analysis (CCA) demonstrated that cortical regions can be grouped into clusters, which can be adjacent or distant from each other, that have similar temporal activation patterns depending on whether the performed motor task is guided by visual or tactile feedback. These analyses highlight the future potential of fNIR imaging to tackle clinically relevant questions regarding the spatiotemporal relations between different sensorimotor cortex regions, e.g. ones involved in the rehabilitation response to motor impairments. PMID:22162826

Khan, Bilal; Chand, Pankaj; Alexandrakis, George

2011-01-01

354

X-ray tangential imaging at NSTX with a Micro Pattern Gas Detector based device  

NASA Astrophysics Data System (ADS)

An innovative system for fast 2-D X-ray imaging has been developed at ENEA Frascati, based on a pinhole coupled to a Micro Pattern Gas Detector with a Gas Electron Multiplier as an amplifying stage. The detector is equipped with a 2-D read-out printed circuit board with 144 pixels. This diagnostic images X-ray emission from the plasma at up to 100 kHz in a selectable energy range. A tangential imaging system has been calibrated in the X-ray energy range 3-8 keV and installed on the NSTX experiment at PPPL. Time resolved, 2-D X-ray images of the NSTX plasma core have been obtained with varying fields of view. Comparisons with the magnetic surfaces calculated by the EFIT code using external magnetics alone show good agreement between reconstructed flux surface and the soft-X ray iso-intensity contours for poloidal beta < 0.6. For greater values of poloidal beta, EFIT indicates an increase of the elongation of the flux surfaces from 1.5 to 2.2, while the X-ray images show that the iso-intensity contours become more circular.

Pacella, D.; Tritz, K.; Stutman, D.; Finkenthal, M.; Leigheb, M.; Kaita, R.; Sabbagh, S.

2003-10-01

355

A new prostate segmentation approach using multispectral magnetic resonance imaging and a statistical pattern classifier  

NASA Astrophysics Data System (ADS)

Prostate segmentation is essential for calculating prostate volume, creating patient-specific prostate anatomical models and image fusion. Automatic segmentation methods are preferable because manual segmentation is timeconsuming and highly subjective. Most of the currently available segmentation methods use a priori knowledge of the prostate shape. However, there is a large variation in prostate shape between patients. Our approach uses multispectral magnetic resonance imaging (MRI) data, containing T1, T2 and proton density (PD) weighted images and the distance from the voxel to the centroid of the prostate, together with statistical pattern classifiers. We investigated the performance of a parametric and a non-parametric classification approach by applying a Baysian-quadratic and a k-nearest-neighbor classifier respectively. An annotated data set is made by manual labeling of the image. Using this data set, the classifiers are trained and evaluated. sThe following results are obtained after three experiments. Firstly, using feature selection we showed that the average segmentation error rates are lowest when combining all three images and the distance with the k-nearest-neighbor classifier. Secondly, the confusion matrix showed that the k-nearest-neighbor classifier has the sensitivity. Finally, the prostate is segmented using both classifier. The segmentation boundaries approach the prostate boundaries for most slices. However, in some slices the segmentation result contained errors near the borders of the prostate. The current results showed that segmenting the prostate using multispectral MRI data combined with a statistical classifier is a promising method.

Maan, Bianca; van der Heijden, Ferdi; Fütterer, Jurgen J.

2012-02-01

356

A Hybrid-Cloud Science Data System Enabling Advanced Rapid Imaging & Analysis for Monitoring Hazards  

NASA Astrophysics Data System (ADS)

Volcanic eruptions, landslides, and levee failures are some examples of hazards that can be more accurately forecasted with sufficient monitoring of precursory ground deformation, such as the high-resolution measurements from GPS and InSAR. In addition, coherence and reflectivity change maps can be used to detect surface change due to lava flows, mudslides, tornadoes, floods, and other natural and man-made disasters. However, it is difficult for many volcano observatories and other monitoring agencies to process GPS and InSAR products in an automated scenario needed for continual monitoring of events. Additionally, numerous interoperability barriers exist in multi-sensor observation data access, preparation, and fusion to create actionable products. Combining high spatial resolution InSAR products with high temporal resolution GPS products--and automating this data preparation & processing across global-scale areas of interests--present an untapped science and monitoring opportunity. The global coverage offered by satellite-based SAR observations, and the rapidly expanding GPS networks, can provide orders of magnitude more data on these hazardous events if we have a data system that can efficiently and effectively analyze the voluminous raw data, and provide users the tools to access data from their regions of interest. Currently, combined GPS & InSAR time series are primarily generated for specific research applications, and are not implemented to run on large-scale continuous data sets and delivered to decision-making communities. We are developing an advanced service-oriented architecture for hazard monitoring leveraging NASA-funded algorithms and data management to enable both science and decision-making communities to monitor areas of interests via seamless data preparation, processing, and distribution. Our objectives: * Enable high-volume and low-latency automatic generation of NASA Solid Earth science data products (InSAR and GPS) to support hazards monitoring. * Facilitate NASA-USGS collaborations to share NASA InSAR and GPS data products, which are difficult to process in high-volume and low-latency, for decision-support. * Enable interoperable discovery, access, and sharing of NASA observations and derived actionable products, and between the observation and decision-making communities. * Enable their improved understanding through visualization, mining, and cross-agency sharing. Existing InSAR & GPS processing packages and other software are integrated for generating geodetic decision support monitoring products. We employ semantic and cloud-based data management and processing techniques for handling large data volumes, reducing end product latency, codifying data system information with semantics, and deploying interoperable services for actionable products to decision-making communities.

Hua, H.; Owen, S. E.; Yun, S.; Lundgren, P.; Moore, A. W.; Fielding, E. J.; Radulescu, C.; Sacco, G.; Stough, T. M.; Mattmann, C. A.; Cervelli, P. F.; Poland, M. P.; Cruz, J.

2012-12-01

357

High-Dimensional Pattern Regression Using Machine Learning: From Medical Images to Continuous Clinical Variables  

PubMed Central

This paper presents a general methodology for high-dimensional pattern regression on medical images via machine learning techniques. Compared with pattern classification studies, pattern regression considers the problem of estimating continuous rather than categorical variables, and can be more challenging. It is also clinically important, since it can be used to estimate disease stage and predict clinical progression from images. In this work, adaptive regional feature extraction approach is used along with other common feature extraction methods, and feature selection technique is adopted to produce a small number of discriminative features for optimal regression performance. Then the Relevance Vector Machine (RVM) is used to build regression models based on selected features. To get stable regression models from limited training samples, a bagging framework is adopted to build ensemble basis regressors derived from multiple bootstrap training samples, and thus to alleviate the effects of outliers as well as facilitate the optimal model parameter selection. Finally, this regression scheme is tested on simulated data and real data via cross-validation. Experimental results demonstrate that this regression scheme achieves higher estimation accuracy and better generalizing ability than Support Vector Regression (SVR). PMID:20056158

Wang, Ying; Fan, Yong; Bhatt, Priyanka; Davatzikos, Christos

2010-01-01

358

Scattering of Visible Radiation by Finite Clouds  

Microsoft Academic Search

A theoretical model of the scattering of shortwave radiation is applied to clouds finite in horizontal extent. The resulting irradiance patterns are then compared with calculations for horizontally semi-infinite clouds. This analysis shows, that the irradiance fields are dramatically dependent upon energy passing through the vertical sides of the finite sized clouds.Directional reflectance of individual cubic clouds is shown to

Thomas B. McKee; Stephen K. Cox

1974-01-01

359

A 10km resolution image of the entire night-time Earth based on cloud-free satellite photographs in the 400-1100nm band  

Microsoft Academic Search

An image of the entire Earth at night is assembled for the first time. It consists of a mosaic of photographs, all taken at local midnight in the 400–1100 nm band, made by the Defense Meteorological Satellite Program over the period 1974–84. Photographs were selected for freedom from clouds, lack of moonlight, high sensitivity and suitability to illustrate various temporal phenomena.

WOODRUFF T SULLIVAN III

1989-01-01

360

Ground-Truthing Moderate Resolution Satellite Imagery with Near-Surface Canopy Images in Hawai'i's Tropical Cloud Forests  

NASA Astrophysics Data System (ADS)

Phenological studies are gaining importance globally as the onset of climate change is impacting the timing of green up and senescence in forest canopies and agricultural regions. Many studies use and analyze land surface phenology (LSP) derived from satellite vegetation index time series (VI's) such as those from Moderate Resolution Imaging Spectroradiometer (MODIS) to monitor changes in phenological events. Seasonality is expected in deciduous temperate forests, while tropical regions are predicted to show more static reflectance readings given their stable and steady state. Due to persistent cloud cover and atmospheric interference in tropical regions, satellite VI time series are often subject to uncertainties and thus require near surface vegetation monitoring systems for ground-truthing. This study has been designed to assess the precision of MODIS phenological signatures using above-canopy, down-looking digital cameras installed on flux towers on the Island of Hawai'i. The cameras are part of the expanding Phenological Eyes Network (PEN) which has been implementing a global network of above-canopy, hemispherical digital cameras for forest and agricultural phenological monitoring. Cameras have been installed at two locations in Hawaii - one on a flux tower in close proximity to the Thurston Lave Tube (HVT) in Hawai'i Volcanoes National Park and the other on a weather station in a section of the Hawaiian Tropical Experimental Forest in Laupaphoehoe (LEF). HVT consists primarily of a single canopy species, ohi'a lehua (Metrosideros polymorpha), with an understory of hapu'u ferns (Cibotium spp), while LEF is similarly comprised with an additional dominant species, Koa (Acacia Koa), included in the canopy structure. Given these species' characteristics, HVT is expected to show little seasonality, while LEF has the potential to deviate slightly during periods following dry and wet seasons. MODIS VI time series data are being analyzed and will be compared to images from the cameras which will have VI's extracted from their RGB image planes and will be normalized to be comparable with MODIS VI's. Given Hawai'i's susceptibility to invasion and delicacy of its endemic species, results from this study will provide necessary site specific detail in determining the reliability of satellite based inference in similar tropical phenology studies. Should satellite images provide adequate information, results from this study will allow for extrapolation across similar understudied tropical forests.

Bergstrom, R.; Miura, T.; Lepczyk, C.; Giambelluca, T. W.; Nullet, M. A.; Nagai, S.

2012-12-01

361

Particle aggregation in volcanic clouds from the 2009 eruption of Redoubt Volcano, Alaska: Observations of Doppler weather radar, satellite images and tephra-fall deposits  

NASA Astrophysics Data System (ADS)

The combined use of weather radar and thermal infrared satellite images provides complementary evidence that can be used to observe and interpret tephra-fall processes. Radar is ideal for characterizing coarse-grained tephra in the eruption column and proximal cloud, while thermal infrared satellite data are better able to characterize the fine-grained distal volcanic cloud. We present observations of radar, satellite images, and character of the tephra-fall deposits from the 2009 eruption of Redoubt Volcano, Alaska. Accretionary tephra-ice pellets (up to 9 mm in diameter) comprised of fine-grained ash (less than 63 micron diameter) were abundant in the many of the proximal tephra-fall deposits. The eruption column and proximal cloud from seventeen explosive events were observed using the MiniMax-250C (MM-250C) volcano-monitoring Doppler weather radar located 80 km from the vent. Radar reflectivity and radial Doppler velocity measurements were made of the column, every 70-90 seconds at a vertical resolution of about 2 km. Radar reflectivity is highly dependent upon particle size and to a lesser extent, concentration. At 80 km distance, the minimum detectable particle diameter for the MM-250C was about 0.2 mm for a mass concentration of 100 g/m3. Thus, the radar was able to observe the aggregate pellets, and not the fine-grained ash. Most of the explosive events were characterized by high radar reflectivity values of 50-60 dBZ in the central core of the eruption column and proximal cloud, which we interpret to be related to the rapid growth of accretionary tephra-ice pellets. Tephra-fall deposits extended for distances of several hundred kilometers and mapped to a minimum mass density of 10 g/m2. However, the MM-250C radar data were only able to observe the dispersed cloud for tens of kilometers from the source, which was well within the 1000 g/m2 isomass contour. Fine-grained ash was prematurely removed from the eruption cloud in proximal locations due to aggregate formation. The relative lack of fine-grained ash may account for the poor thermal infrared brightness temperature signals observed in satellite images for many of the distal volcanic clouds from the 2009 eruption, and possibly from the 1989-90 eruption as well. Time-series of radial Doppler velocity images documented the transition from turbulent mixing in the column to larger scale entrainment within the proximal cloud. Large scale entrainment begins to develop within minutes of eruption onset. Most of the eruption clouds from the explosive events reached the stratosphere, but the large scale entrainment appears to be better developed in the tropospheric portion of the cloud.

Schneider, D. J.; Wallace, K. L.; Mastin, L. G.

2012-12-01

362

Applying Chemical Imaging Analysis to Improve Our Understanding of Cold Cloud Formation  

NASA Astrophysics Data System (ADS)

The impact that atmospheric ice nucleation has on the global radiation budget is one of the least understood problems in atmospheric sciences. This is in part due to the incomplete understanding of various ice nucleation pathways that lead to ice crystal formation from pre-existing aerosol particles. Studies investigating the ice nucleation propensity of laboratory generated particles indicate that individual particle types are highly selective in their ice nucleating efficiency. This description of heterogeneous ice nucleation would present a challenge when applying to the atmosphere which contains a complex mixture of particles. Here, we employ a combination of micro-spectroscopic and optical single particle analytical methods to relate particle physical and chemical properties with observed water uptake and ice nucleation. Field-collected particles from urban environments impacted by anthropogenic and marine emissions and aging processes are investigated. Single particle characterization is provided by computer controlled scanning electron microscopy with energy dispersive analysis of X-rays (CCSEM/EDX) and scanning transmission X-ray microscopy with near edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). A particle-on-substrate approach coupled to a vapor controlled cooling-stage and a microscope system is applied to determine the onsets of water uptake and ice nucleation including immersion freezing and deposition ice nucleation as a function of temperature (T) as low as 200 K and relative humidity (RH) up to water saturation. We observe for urban aerosol particles that for T > 230 K the oxidation level affects initial water uptake and that subsequent immersion freezing depends on particle mixing state, e.g. by the presence of insoluble particles. For T < 230 K the particles initiate deposition ice nucleation well below the homogeneous freezing limit. Particles collected throughout one day for similar meteorological conditions show very similar deposition ice nucleation efficiencies, indicating that chemical changes due to aging processes might not have a dominant effect on this nucleation pathway consistent with previous observations. The field-collected particles exhibit ice nucleation efficiencies that suggest that these kinds of particles can play a potential role in mixed-phase and cirrus cloud formation. Initial results applying single particle IN analysis using CCSEM/EDX and STXM/NEXAFS reveal that a significant amount of IN are coated by organics and, thus, are similar to the majority of the particles that do not nucleate ice. However respective particle cores can be of different mineral composition. This suggests that highly abundant and chemically complex aerosol, typical of an urban environment, initiate ice despite possessing potentially mediocre ice nucleation efficiency. This is in contrast to the general notion that the most efficient IN and usually less abundant particles of a population will govern ice nucleation in an air parcel.

Laskin, A.; Knopf, D. A.; Wang, B.; Alpert, P. A.; Roedel, T.; Gilles, M. K.; Moffet, R.; Tivanski, A.

2012-12-01

363

A Sparse Representation-Based Algorithm for Pattern Localization in Brain Imaging Data Analysis  

PubMed Central

Considering the two-class classification problem in brain imaging data analysis, we propose a sparse representation-based multi-variate pattern analysis (MVPA) algorithm to localize brain activation patterns corresponding to different stimulus classes/brain states respectively. Feature selection can be modeled as a sparse representation (or sparse regression) problem. Such technique has been successfully applied to voxel selection in fMRI data analysis. However, single selection based on sparse representation or other methods is prone to obtain a subset of the most informative features rather than all. Herein, our proposed algorithm recursively eliminates informative features selected by a sparse regression method until the decoding accuracy based on the remaining features drops to a threshold close to chance level. In this way, the resultant feature set including all the identified features is expected to involve all the informative features for discrimination. According to the signs of the sparse regression weights, these selected features are separated into two sets corresponding to two stimulus classes/brain states. Next, in order to remove irrelevant/noisy features in the two selected feature sets, we perform a nonparametric permutation test at the individual subject level or the group level. In data analysis, we verified our algorithm with a toy data set and an intrinsic signal optical imaging data set. The results show that our algorithm has accurately localized two class-related patterns. As an application example, we used our algorithm on a functional magnetic resonance imaging (fMRI) data set. Two sets of informative voxels, corresponding to two semantic categories (i.e., “old people” and “young people”), respectively, are obtained in the human brain. PMID:23227167

He, Lin; Lu, Haidong; Gu, Zhenghui; Sun, Pei

2012-01-01

364

Neptune's cloud structure in 1989 - Photometric variations and correlation with ground-based images  

NASA Technical Reports Server (NTRS)

Ground-based photoelectric photometry in b, y, and the 6190 and 7250 A methane-bands, as well as spectrum scans of the methane 6190 A band and CCD images at 6190 and 8900 A, were obtained for Neptune during Voyager 2's approach of that planet on August 24, 1989. Photometric variations are presently correlated with the disk transit of bright planetary features, and the changes in feature distribution and brightness noted in the results are evaluated for implications bearing on long-term variability. It is suggested that the long-term secular variation is related to a slow change in a size of location of both the bright companion and the Great Dark Spot.

Lockwood, G. W.; Thompson, D. T.; Hammel, H. B.; Birch, P.; Candy, M.

1991-01-01

365

A preliminary computer pattern analysis of satellite images of mature extratropical cyclones  

NASA Technical Reports Server (NTRS)

This study has applied computerized pattern analysis techniques to the location and classification of features of several mature extratropical cyclones that were depicted in GOES satellite images. These features include the location of the center of the cyclone vortex core and the location of the associated occluded front. The cyclone type was classified in accord with the scheme of Troup and Streten. The present analysis was implemented on a personal computer; results were obtained within approximately one or two minutes without the intervention of an analyst.

Burfeind, Craig R.; Weinman, James A.; Barkstrom, Bruce R.

1987-01-01

366

Differentiation of bacterial colonies and temporal growth patterns using hyperspectral imaging  

NASA Astrophysics Data System (ADS)

Detection and identification of bacteria are important for health and safety. Hyperspectral imaging offers the potential to capture unique spectral patterns and spatial information from bacteria which can then be used to detect and differentiate bacterial species. Here, hyperspectral imaging has been used to characterize different bacterial colonies and investigate their growth over time. Six bacterial species (Pseudomonas fluorescens, Escherichia coli, Serratia marcescens, Salmonella enterica, Staphylococcus aureus, Enterobacter aerogenes) were grown on tryptic soy agar plates. Hyperspectral data were acquired immediately after, 24 hours after, and 96 hours after incubation. Spectral signatures from bacterial colonies demonstrated repeatable measurements for five out of six species. Spatial variations as well as changes in spectral signatures were observed across temporal measurements within and among species at multiple wavelengths due to strengthening or weakening reflectance signals from growing bacterial colonies based on their pigmentation. Between-class differences and within-class similarities were the most prominent in hyperspectral data collected 96 hours after incubation.

Mehrübeoglu, Mehrube; Buck, Gregory W.; Livingston, Daniel W.

2014-09-01

367

Optimized temporally deconvolved Ca²? imaging allows identification of spatiotemporal activity patterns of CA1 hippocampal ensembles.  

PubMed

Hippocampal activity is characterized by the coordinated firing of a subset of neurons. Such neuronal ensembles can either be driven by external stimuli to form new memory traces or be reactivated by intrinsic mechanisms to reactivate and consolidate old memories. Hippocampal network oscillations orchestrate this coherent activity. One key question is how the topology, i.e. the functional connectivity of neuronal networks supports their desired function. Recently, this has been addressed by characterizing the intrinsic properties for the highly recurrently connected CA3 region using organotypic slice cultures and Ca(2+) imaging. In the present study, we aimed to determine the properties of CA1 hippocampal ensembles at high temporal and multiple single cell resolution. Thus, we performed Ca(2+) imaging using the chemical fluorescent Ca(2+) indicator Oregon Green BAPTA 1-AM. To achieve most physiological conditions, we used acute hippocampal slices that were recorded in a so-called interface chamber. To faithfully reconstruct firing patterns of multiple neurons in the field of view, we optimized deconvolution-based detection of action potential associated Ca(2+) events. Our approach outperformed currently available detection algorithms by its sensitivity and robustness. In combination with advanced network analysis, we found that acute hippocampal slices contain a median of 11 CA1 neuronal ensembles with a median size of 4 neurons. This apparently low number of neurons is likely due to the confocal imaging acquisition and therefore yields a lower limit. The distribution of ensemble sizes was compatible with a scale-free topology, as far as can be judged from data with small cell numbers. Interestingly, cells were more tightly clustered in large ensembles than in smaller groups. Together, our data show that spatiotemporal activity patterns of hippocampal neuronal ensembles can be reliably detected with deconvolution-based imaging techniques in mouse hippocampal slices. The here presented techniques are fully applicable to similar studies of distributed optical measurements of neuronal activity (in vivo), where signal-to-noise ratio is critical. PMID:24650598

Pfeiffer, Thomas; Draguhn, Andreas; Reichinnek, Susanne; Both, Martin

2014-07-01

368

Cloud Fun  

NSDL National Science Digital Library

Learners complete a series of hands-on and investigative activities to explore cumulus clouds. Learners observe cumulus clouds outside, read a book about how cumulus clouds differ from other clouds, and create a list of words that describe cumulus clouds. Then, learners create their own cumulus cloud out of white paper and complete the Cloud Fun Student Activity sheet that includes a description of the cloud and what the weather was like on the day the cloud was observed. Learners will use their five senses to describe their clouds. Clouds can be displayed in the classroom or assembled into a class book. This lesson guide includes brief background information about cumulus clouds, adaptations for younger and older learners, and extension ideas.

Program, The G.

2006-01-01

369

Automatic classification of prostate stromal tissue in histological images using Haralick descriptors and Local Binary Patterns  

NASA Astrophysics Data System (ADS)

In this paper we presente a classification system that uses a combination of texture features from stromal regions: Haralick features and Local Binary Patterns (LBP) in wavelet domain. The system has five steps for classification of the tissues. First, the stromal regions were detected and extracted using segmentation techniques based on thresholding and RGB colour space. Second, the Wavelet decomposition was applied in the extracted regions to obtain the Wavelet coefficients. Third, the Haralick and LBP features were extracted from the coefficients. Fourth, relevant features were selected using the ANOVA statistical method. The classication (fifth step) was performed with Radial Basis Function (RBF) networks. The system was tested in 105 prostate images, which were divided into three groups of 35 images: normal, hyperplastic and cancerous. The system performance was evaluated using the area under the ROC curve and resulted in 0.98 for normal versus cancer, 0.95 for hyperplasia versus cancer and 0.96 for normal versus hyperplasia. Our results suggest that texture features can be used as discriminators for stromal tissues prostate images. Furthermore, the system was effective to classify prostate images, specially the hyperplastic class which is the most difficult type in diagnosis and prognosis.

Oliveira, D. L. L.; Nascimento, M. Z.; Neves, L. A.; Batista, V. R.; Godoy, M. F.; Jacomini, R. S.; Duarte, Y. A. S.; Arruda, P. F. F.; Neto, D. S.

2014-03-01

370

Abnormal pattern detection in Wireless Capsule Endoscopy images using nonlinear analysis in RGB color space.  

PubMed

In recent years, an innovative method has been developed for the non-invasive observation of the gastrointestinal tract (GT), namely Wireless Capsule Endoscopy (WCE). WCE especially enables a detailed inspection of the entire small bowel and identification of its clinical lesions. However, the foremost disadvantage of this technological breakthrough is the time consuming task of reviewing the vast amount of images produced. To address this, a novel technique for distinguishing pathogenic endoscopic images related to ulcer, the most common disease of GT, is presented here. Towards this direction, the Bidimensional Ensemble Empirical Mode Decomposition was applied to RGB color images of the small bowel acquired by a WCE system in order to extract their Intrinsic Mode Functions (IMFs). The IMFs reveal differences in structure from their finest to their coarsest scale, providing a new analysis domain. Additionally, lacunarity analysis was employed as a method to quantify and extract the texture patterns of the ulcer regions and the normal mucosa, respectively, in order to discriminate the abnormal from the normal images. Experimental results demonstrated promising classification accuracy (>95%), exhibiting a high potential towards WCE-based analysis. PMID:21097046

Charisis, Vasileios; Hadjileontiadis, Leontios J; Liatsos, Christos N; Mavrogiannis, Christos C; Sergiadis, George D

2010-01-01

371

Near-infrared Imaging Polarimetry of the Serpens Cloud Core: Magnetic Field Structure, Outflows, and Inflows in a Cluster Forming Clump  

NASA Astrophysics Data System (ADS)

We made deep near-infrared (JHKs) imaging polarimetry toward the Serpens cloud core, which is a nearby, active cluster forming region. The polarization vector maps show that the near-infrared reflection light in this region mainly originates from SVS 2 and SVS 20, and enable us to detect 24 small infrared reflection nebulae associated with young stellar objects. Polarization measurements of near-infrared point sources indicate an hourglass-shaped magnetic field, of which the symmetry axis is nearly perpendicular to the elongation of the C18O (J = 1-0) or submillimeter continuum emission. The bright part of C18O (J = 1-0), submillimeter continuum cores as well as many Class 0/I objects are located just toward the constriction region of the hourglass-shaped magnetic field. Applying the Chandrasekhar and Fermi method and taking into account the recent study on the signal integration effect for the dispersion component of the magnetic field, the magnetic field strength was estimated to be ~100 ?G, suggesting that the ambient region of the Serpens cloud core is moderately magnetically supercritical. This suggests that the Serpens cloud core first contracted along the magnetic field as an elongated cloud, which is perpendicular to the magnetic field, and that the central part then contracted across the magnetic field due to the high density in the central region of the cloud core, where star formation is actively continuing. Comparison of this magnetic field with previous observations of molecular gas and large-scale outflows suggests a possibility that the cloud dynamics are controlled by the magnetic field, protostellar outflows, and gravitational inflows. Furthermore, the outflow energy injection rate appears to be larger than the dissipation rate of the turbulent energy in this cloud, indicating that the outflows are the main source of turbulence and that the magnetic field plays an important role both in allowing the outflow energy to escape from the central region of the cloud core and enabling the gravitational inflows from the ambient region to the central region. These characteristics appear to be in good agreement with the outflow-driven turbulence model and imply the importance of the magnetic field to continuous star formation in the center region of the cluster forming region.

Sugitani, Koji; Nakamura, Fumitaka; Tamura, Motohide; Watanabe, Makoto; Kandori, Ryo; Nishiyama, Shogo; Kusakabe, Nobuhiko; Hashimoto, Jun; Nagata, Tetsuya; Sato, Shuji

2010-06-01

372

Near-Infrared Imaging Polarimetry of the Serpens Cloud Core: Magnetic Field Structure, Outflows, and Inflows in A Cluster Forming Clump  

E-print Network

We made deep NIR imaging polarimetry toward the Serpens cloud core. The polarization vector maps enable us to newly detect 24 small IR reflection nebulae with YSOs. Polarization measurements of NIR point sources indicate an hourglass-shaped magnetic field, of which symmetry axis is nearly perpendicular to the elongation of the C18O (J=1-0) or submillimeter continuum emission. The bright part of C18O (J=1-0), submillimeter continuum cores as well as many class 0/I objects are located just toward the constriction region of the hourglass-shaped magnetic field. Applying the CF method, the magnetic field strength was estimated to be ~100 muG, suggesting that the ambient region of the Serpens cloud core is moderately magnetically supercritical. These suggest that the Serpens cloud core first contracted along the magnetic field to be an elongated cloud, which is perpendicular to the magnetic field, and that then the central part contracted cross the magnetic field due to the high density in the central region of the...

Sugitani, Koji; Tamura, Motohide; Watanabe, Makoto; Kandori, Ryo; Nishiyama, Shogo; Kusakabe, Nobuhiko; Hashimoto, Jun; Nagata, Tetsuya; Sato, Shuji

2010-01-01

373

Study of combined filter based on wavelet transform to denoise stripe images of electronic speckle shearography pattern interferometry  

NASA Astrophysics Data System (ADS)

Stripe images of electronic speckle shearography pattern interferometry, in which stripe distribution are correlated with vertical micro distortion or micro vibration of objects, are severely disturbed by noises, and so denoising stripe images of electronic speckle shearography pattern interferometry is necessary to extract useful stripe distribution information. Denoising methods and flow for stripe images of electronic speckle shearography pattern interferometry are analyzed in this paper to get the stripe distribution correlated with vertical micro distortion or micro vibration of objects. The noises in the stripe images of electronic speckle shearography pattern interferometry are comprised of speckle noise and other random noises induced by environmental disturb and instrumental performance, so it's difficult to use familiar filters, such as mean-value filter, medium-value filter and adaptive filter, etc, to remove all noises in the stripe images. The combined filter composed of mean-value filter and wavelet filter is designed to denoise stripe images. The aim of mean-value filter is to remove random noises induced by environmental disturb and instrumental performance, and then the wavelet filter, in which the Meyer wavelet is adopted, is designed to remove speckle noise in the stripe images. The final stripe distribution images after denoising and binarization are listed to prove the denoising validity of combined filter based on wavelet transform.

Liu, Zhongling; Jing, Chao; Zhang, Yimo

2011-11-01

374

IEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1 3D Face Reconstruction from a Single Image  

E-print Network

a Single Image using a Single Reference Face Shape Ira Kemelmacher-Shlizerman, Ronen Basri, Member, IEEEIEEE TRANSACTIONS ON PATTERN ANALYSIS AND MACHINE INTELLIGENCE 1 3D Face Reconstruction from of faces. Our method obtains as input a single image and uses a mere single 3D reference model

Kemelmacher-Shlizerman, Ira

375

MR imaging of patellar instability: injury patterns and assessment of risk factors.  

PubMed

First-time patellar dislocation typically occurs with twisting knee motions, during which the medial ligamentous stabilizers rupture, and the patella strikes against the lateral femoral condyle. The typical injury pattern is a tear of the medial patellofemoral ligament (MPFL) and bone bruises of the patella and the lateral femoral condyle. Additionally, complex injuries to bone, cartilage, and ligaments may occur. The ensuing loss of medial restraint favors future patellar dislocations, especially if additional risk factors are present. Recurrent patellar dislocations usually occur in individuals with anatomic variants of the patellar stabilizers, such as trochlear dysplasia, patella alta, and lateralization of the tibial tuberosity. Magnetic resonance (MR) imaging is reliable in identifying risk factors for chronic patellar instability and in assessing knee joint damage associated with patellar dislocation. MR imaging can thus provide important information for individually tailored treatment. Patients with primary patellar dislocation without severe internal derangement who lack major risk factors can be treated conservatively. Patients with pronounced ligamentous tears or large osteochondral lesions require prompt surgery. In addition, surgical correction of anatomic variants will help reduce the potential for chronic instability. The most common procedures, in addition to MPFL reconstruction, include trochleoplasty, medialization of the tibial tuberosity, and medial capsular plication. For comprehensive assessment of patellar dislocation, a radiologist should be able to identify typical injury patterns, know standard methods to assess risk factors for patellar instability, and be familiar with surgical options. PMID:20631363

Diederichs, Gerd; Issever, Ahi S; Scheffler, Sven

2010-01-01

376

Detection and evaluation of droplet and bubble fringe patterns in images of planar interferometric measurement techniques using the wavelet transform  

NASA Astrophysics Data System (ADS)

The acquired images of interferometric particle sizing techniques are characterized by intense fringe pattern overlapping in dense droplet and bubble areas, which hinders the image processing process and subsequent information extraction. Methods employed, such as thresholding and the Hough transform and template cross-correlation, exhibit weaknesses when processing such dense areas of interest. We investigate the viability of applying the wavelet transform (WT) for the detection of the fringe pattern centers and the evaluation of the particle size. We present the basics of the WT using the Mexican hat, which exhibits excellent localization properties and present two different alternatives routes in detecting the fringe patterns in the compressed and uncompressed fringe pattern cases. We found that in comparison to the most reported methods for image evaluation, such as intensity thresholding and plain cross-correlation, the WT is a very efficient tool for detecting the patterns, even in images with high-number fringe pattern areas. The usage of the WT for the sizing of the imaged droplets and bubbles is also examined, in comparison to the Fast Fourier Transform (FFT).

Hardalupas, Y.; Taylor, A. M. K. P.; Zarogoulidis, K.

2014-08-01

377

Cloud top structure of a tornadic thunderstorm from 3 min interval stereo satellite images compared with radar and other observations  

NASA Technical Reports Server (NTRS)

Cloud heights from 3 min interval GOES EAST/GOES WEST stereo pairs are shown to provide an important new tool for studying severe convective storms with potential for the detection of severe local storms. It is possible to use these data for observing cloud top structure as a function of time on a size scale of few kilometers with quantitative height measurements with relative and absolute accuracies on the order of + or - 0.5 km. It is noted that stereo height measurements detect cirrus anvil cloud decks at two altitudes corresponding to a lower stable layer and the main tropopause.

Hasler, A. F.; Adler, R. F.

1980-01-01

378

Automated cloud and shadow detection and filling using two-date Landsat imagery in the United States  

USGS Publications Warehouse

A simple, efficient, and practical approach for detecting cloud and shadow areas in satellite imagery and restoring them with clean pixel values has been developed. Cloud and shadow areas are detected using spectral information from the blue, shortwave infrared, and thermal infrared bands of Landsat Thematic Mapper or Enhanced Thematic Mapper Plus imagery from two dates (a target image and a reference image). These detected cloud and shadow areas are further refined using an integration process and a false shadow removal process according to the geometric relationship between cloud and shadow. Cloud and shadow filling is based on the concept of the Spectral Similarity Group (SSG), which uses the reference image to find similar alternative pixels in the target image to serve as replacement values for restored areas. Pixels are considered to belong to one SSG if the pixel values from Landsat bands 3, 4, and 5 in the reference image are within the same spectral ranges. This new approach was applied to five Landsat path/rows across different landscapes and seasons with various types of cloud patterns. Results show that almost all of the clouds were captured with minimal commission errors, and shadows were detected reasonably well. Among five test scenes, the lowest producer's accuracy of cloud detection was 93.9% and the lowest user's accuracy was 89%. The overall cloud and shadow detection accuracy ranged from 83.6% to 99.3%. The pixel-filling approach resulted in a new cloud-free image that appears seamless and spatially continuous despite differences in phenology between the target and reference images. Our methods offer a straightforward and robust approach for preparing images for the new 2011 National Land Cover Database production.

Jin, Suming; Homer, Collin; Yang, Limin; Xian, George; Fry, Joyce; Danielson, Patrick; Townsend, Philip A.

2013-01-01

379

A Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the (rho) Ophiuchi Cloud Core  

NASA Technical Reports Server (NTRS)

Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the (rho) Ophiuchi cloud are presented. Data were acquired at the Palomar 5m and at the Keck 10m telescopes with the MIRLIN and LWS instruments, at 0'.5 and 0'.25 resolutions, respectively. Of 172 survey objects, 85 were detected. Among the 22 multiple systems observed, 15 were resolved and their individual component fluxes determined. A plot of the frequency distribution of the detected objects with SED spectral slope shows that YSOs spend approx.4 x 10(exp 5) yr in the flat-spectrum phase, clearing out their remnant infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects and is found to occur for all SED classes with optically thick disks. Large-amplitude near-infrared variability, also found for all SED classes with optically thick disks, seems to occur with somewhat higher frequency at the earlier evolutionary stages. Although a general trend of mid-infrared excess and near-infrared veiling exists progressing through SED classes, with Class I objects generally exhibiting r(sub K) >= 1, flat-spectrum objects with r(sub K) >= 0.58, and Class III objects with r(sub K) =0, Class II objects exhibit the widest range of r(sub K) values, ranging from 0 <= r(sub K) <= 4.5. However, the highly variable value of veiling that a single source can exhibit in any of the SED classes in which active disk accretion can take place is striking and is direct observational evidence for highly time-variable accretion activity in disks. Finally, by comparing mid-infrared versus near-infrared excesses in a subsample with well-determined effective temperatures and extinction values, disk-clearing mechanisms are explored. The results are consistent with disk clearing proceeding from the inside out.

Barsony, Mary; Ressler, Michael E.; Marsh, Kenneth A.

2005-01-01

380

A Mid-Infrared Imaging Survey of Embedded Young Stellar Objects in the Rho Ophiuchi Cloud Core  

E-print Network

Results of a comprehensive, new, ground-based mid-infrared imaging survey of the young stellar population of the Rho Ophiuchi cloud are presented. Data were acquired at the Palomar 5-m and at the Keck 10-m telescopes with the MIRLIN and LWS instruments, at 0.25 arcsec and 0.25 arcsec resolutions, respectively. Of 172 survey objects, 85 were detected. Among the 22 multiple systems observed, 15 were resolved and their individual component fluxes determined. A plot of the frequency distribution of the detected objects with SED spectral slope shows that YSOs spend ~400,000 yr in the Flat Spectrum phase, clearing out their remnant infall envelopes. Mid-infrared variability is found among a significant fraction of the surveyed objects, and is found to occur for all SED classes with optically thick disks. Large-amplitude near-infrared variability, also found for all SED classes with optically thick disks, seems to occur with somewhat higher frequency at the earlier evolutionary stages. Although a general trend of mid-infrared excess and NIR veiling exists proceeding through SED classes, with Class I objects generally exhibiting K-veilings > 1, Flat Spectrum objects with K-veilings > 0.58, and Class III objects with K-veilings =0, Class II objects exhibit the widest range of K-band veiling values, 0-4.5. However, the highly variable value of veiling that a single source can exhibit in any of the SED classes in which active disk accretion can take place is striking, and is direct observational evidence for highly time-variable accretion activity in disks. Finally, by comparing mid-infrared vs. near-infrared excesses in a subsample with well-determined effective temperatures and extinction values, disk clearing mechanisms are explored. The results are consistent with disk clearing proceeding from the inside-out.

Mary Barsony; Michael E. Ressler; Kenneth A. Marsh

2005-04-19

381

A pattern recognition system for locating small volvanoes in Magellan SAR images of Venus  

NASA Technical Reports Server (NTRS)

The Magellan data set constitutes an example of the large volumes of data that today's instruments can collect, providing more detail of Venus than was previously available from Pioneer Venus, Venera 15/16, or ground-based radar observations put together. However, data analysis technology has not kept pace with data collection and storage technology. Due to the sheer size of the data, complete and comprehensive scientific analysis of such large volumes of image data is no longer feasible without the use of computational aids. Our progress towards developing a pattern recognition system for aiding in the detection and cataloging of small-scale natural features in large collections of images is reported. Combining classical image processing, machine learning, and a graphical user interface, the detection of the 'small-shield' volcanoes (less than 15km in diameter) that constitute the most abundant visible geologic feature in the more that 30,000 synthetic aperture radar (SAR) images of the surface of Venus are initially targeted. Our eventual goal is to provide a general, trainable tool for locating small-scale features where scientists specify what to look for simply by providing examples and attributes of interest to measure. This contrasts with the traditional approach of developing problem specific programs for detecting Specific patterns. The approach and initial results in the specific context of locating small volcanoes is reported. It is estimated, based on extrapolating from previous studies and knowledge of the underlying geologic processes, that there should be on the order of 10(exp 5) to 10(exp 6) of these volcanoes visible in the Magellan data. Identifying and studying these volcanoes is fundamental to a proper understanding of the geologic evolution of Venus. However, locating and parameterizing them in a manual manner is forbiddingly time-consuming. Hence, the development of techniques to partially automate this task were undertaken. The primary constraints for this particular problem are that the method must be reasonably robust and fast. Unlike most geological features, the small volcanoes of Venus can be ascribed to a basic process that produces features with a short list of readily defined characteristics differing significantly from other surface features on Venus. For pattern recognition purposes the relevant criteria include (1) a circular planimetric outline, (2) known diameter frequency distribution from preliminary studies, (3) a limited number of basic morphological shapes, and (4) the common occurrence of a single, circular summit pit at the center of the edifice.

Burl, M. C.; Fayyad, U. M.; Smyth, P.; Aubele, J. C.; Crumpler, L. S.

1993-01-01

382

Investigation into diagnostic agreement using automated computer-assisted histopathology pattern recognition image analysis  

PubMed Central

The extent to which histopathology pattern recognition image analysis (PRIA) agrees with microscopic assessment has not been established. Thus, a commercial PRIA platform was evaluated in two applications using whole-slide images. Substantial agreement, lacking significant constant or proportional errors, between PRIA and manual morphometric image segmentation was obtained for pulmonary metastatic cancer areas (Passing/Bablok regression). Bland-Altman analysis indicated heteroscedastic measurements and tendency toward increasing variance with increasing tumor burden, but no significant trend in mean bias. The average between-methods percent tumor content difference was -0.64. Analysis of between-methods measurement differences relative to the percent tumor magnitude revealed that method disagreement had an impact primarily in the smallest measurements (tumor burden <3%). Regression-based 95% limits of agreement indicated substantial agreement for method interchangeability. Repeated measures revealed concordance correlation of >0.988, indicating high reproducibility for both methods, yet PRIA reproducibility was superior (C.V.: PRIA = 7.4, manual = 17.1). Evaluation of PRIA on morphologically complex teratomas led to diagnostic agreement with pathologist assessments of pluripotency on subsets of teratomas. Accommodation of the diversity of teratoma histologic features frequently resulted in detrimental trade-offs, increasing PRIA error elsewhere in images. PRIA error was nonrandom and influenced by variations in histomorphology. File-size limitations encountered while training algorithms and consequences of spectral image processing dominance contributed to diagnostic inaccuracies experienced for some teratomas. PRIA appeared better suited for tissues with limited phenotypic diversity. Technical improvements may enhance diagnostic agreement, and consistent pathologist input will benefit further development and application of PRIA. PMID:22616030

Webster, Joshua D.; Michalowski, Aleksandra M.; Dwyer, Jennifer E.; Corps, Kara N.; Wei, Bih-Rong; Juopperi, Tarja; Hoover, Shelley B.; Simpson, R. Mark

2012-01-01

383

Investigation into diagnostic agreement using automated computer-assisted histopathology pattern recognition image analysis.  

PubMed

The extent to which histopathology pattern recognition image analysis (PRIA) agrees with microscopic assessment has not been established. Thus, a commercial PRIA platform was evaluated in two applications using whole-slide images. Substantial agreement, lacking significant constant or proportional errors, between PRIA and manual morphometric image segmentation was obtained for pulmonary metastatic cancer areas (Passing/Bablok regression). Bland-Altman analysis indicated heteroscedastic measurements and tendency toward increasing variance with increasing tumor burden, but no significant trend in mean bias. The average between-methods percent tumor content difference was -0.64. Analysis of between-methods measurement differences relative to the percent tumor magnitude revealed that method disagreement had an impact primarily in the smallest measurements (tumor burden <3%). Regression-based 95% limits of agreement indicated substantial agreement for method interchangeability. Repeated measures revealed concordance correlation of >0.988, indicating high reproducibility for both methods, yet PRIA reproducibility was superior (C.V.: PRIA = 7.4, manual = 17.1). Evaluation of PRIA on morphologically complex teratomas led to diagnostic agreement with pathologist assessments of pluripotency on subsets of teratomas. Accommodation of the diversity of teratoma histologic features frequently resulted in detrimental trade-offs, increasing PRIA error elsewhere in images. PRIA error was nonrandom and influenced by variations in histomorphology. File-size limitations encountered while training algorithms and consequences of spectral image processing dominance contributed to diagnostic inaccuracies experienced for some teratomas. PRIA appeared better suited for tissues with limited phenotypic diversity. Technical improvements may enhance diagnostic agreement, and consistent pathologist input will benefit further development and application of PRIA. PMID:22616030

Webster, Joshua D; Michalowski, Aleksandra M; Dwyer, Jennifer E; Corps, Kara N; Wei, Bih-Rong; Juopperi, Tarja; Hoover, Shelley B; Simpson, R Mark

2012-01-01

384

Uncommon primary pelvic retroperitoneal masses in adults: a pattern-based imaging approach.  

PubMed

There is a broad spectrum of primary pelvic retroperitoneal masses in adults that demonstrate characteristic epidemiologic and histopathologic features and natural histories. These masses may be classified into five distinct subgroups using a pattern-based approach that takes anatomic distribution and certain imaging characteristics into account, allowing greater accuracy in their detection and characterization and helping to optimize patient management. The five groups are cystic (serous and mucinous epithelial neoplasms, pelvic lymphangioma, tailgut cyst, ancient schwannoma), vascular or hypervascular (solitary fibrous tumor, paraganglioma, pelvic arteriovenous malformation, Klippel-Trénaunay-Weber syndrome, extraintestinal GIST [gastrointestinal stromal tumor]), fat-containing (lipoma, liposarcoma, myelolipoma, presacral teratoma), calcified (calcified lymphocele, calcified rejected transplant kidney, rare sarcomas), and myxoid (schwannoma, plexiform neurofibroma, myxoma).Cross-sectional imaging modalities help differentiate the more common gynecologic neoplasms from more unusual masses. In particular, the tissue-specific multiplanar capability of high-resolution magnetic resonance imaging permits better tumor localization and internal characterization, thereby serving as a road map for surgery. PMID:22582360

Shanbhogue, Alampady K; Fasih, Najla; Macdonald, David B; Sheikh, Adnan M; Menias, Christine O; Prasad, Srinivasa R

2012-01-01

385

Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging lidar  

Microsoft Academic Search

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is

Steven P. Love; Anthony B. Davis; Charles A. Rohde; Larry Tellier; Cheng Ho

2002-01-01

386

Mesoscale cloud phenomena observed by LANDSAT  

NASA Technical Reports Server (NTRS)

Examples of certain mesoscale cloud features - jet cirrus, eddies/vortices, cloud banding, and wave clouds - were collected from LANDSAT imagery and placed into Mason's four groups of causes of cloud formation based on the mechanism of vertical motion which produces condensation. These groups are as follows: (1) layer clouds formed by widespread regular ascent; (2) layer clouds caused by irregular stirring motions; (3) convective clouds; and (4) clouds formed by orographic disturbances. These mechanisms explain general cloud formation. Once formed, other forces may play a role in the deformation of a cloud or cloud mass into unusual and unique meso- and microscale patterns. Each example presented is followed by a brief discussion describing the synoptic situation, and some inference into the formation and occurrence of the more salient features. No major attempt was made to discuss in detail the meteorological and topographic interplay producing these mesoscale features.

Ormsby, J. P.

1977-01-01

387

Cloud Protocols  

NSDL National Science Digital Library

The purpose of this activity is to observe the type and cover of clouds including contrails. Students observe which of ten types of clouds and how many of three types of contrails are visible and how much of the sky is covered by clouds (other than contrails) and how much is covered by contrails. Intended outcomes are that students learn how to make estimates from observations and how to categorize specific clouds following general descriptions for the categories. They will learn the meteorological concepts of cloud heights, types, and cloud cover and learn the ten basic cloud types. Supporting background materials for both student and teacher are included.

The GLOBE Program, UCAR (University Corporation for Atmospheric Research)

2003-08-01

388

Tibial Stress Changes in New Combat Recruits for Special Forces: Patterns and Timing at MR Imaging.  

PubMed

Purpose To characterize the incidence, location, grade, and patterns of magnetic resonance (MR) imaging findings in the tibia in asymptomatic recruits before and after 4-month basic training and to investigate whether MR imaging parameters correlated with pretraining activity levels or with future symptomatic injury. Materials and Methods This study was approved by three institutional review boards and was conducted in compliance with HIPAA requirements. Volunteers were included in the study after they signed informed consent forms. MR imaging of the tibia of 55 men entering the Israeli Special Forces was performed on recruitment day and after basic training. Ten recruits who did not perform vigorous self-training prior to and during service served as control subjects. MR imaging studies in all recruits were evaluated for presence, type, length, and location of bone stress changes in the tibia. Anthropometric measurements and activity history data were collected. Relationships between bone stress changes, physical activity, and clinical findings and between lesion size and progression were analyzed. Results Bone stress changes were seen in 35 of 55 recruits (in 26 recruits at time 0 and in nine recruits after basic training). Most bone stress changes consisted of endosteal marrow edema. Approximately 50% of bone stress changes occurred between the middle and distal thirds of the tibia. Lesion size at time 0 had significant correlation with progression. All endosteal findings smaller than 100 mm resolved or did not change, while most findings larger than 100 mm progressed. Of 10 control subjects, one had bone stress changes at time 0, and one had bone stress changes at 4 months. Conclusion Most tibial bone stress changes occurred before basic training, were usually endosteal, occurred between the middle and distal thirds of the tibia, were smaller than 100 mm, and did not progress. These findings are presumed to represent normal bone remodeling. © RSNA, 2014. PMID:25025463

Hadid, Amir; Moran, Daniel S; Evans, Rachel K; Fuks, Yael; Schweitzer, Mark E; Shabshin, Nogah

2014-11-01

389

Invisible Cirrus Clouds  

NASA Technical Reports Server (NTRS)

The Moderate-resolution Imaging Spectroradiometer's (MODIS') cloud detection capability is so sensitive that it can detect clouds that would be indistinguishable to the human eye. This pair of images highlights MODIS' ability to detect what scientists call 'sub-visible cirrus.' The image on top shows the scene using data collected in the visible part of the electromagnetic spectrum-the part our eyes can see. Clouds are apparent in the center and lower right of the image, while the rest of the image appears to be relatively clear. However, data collected at 1.38um (lower image) show that a thick layer of previously undetected cirrus clouds obscures the entire scene. These kinds of cirrus are called 'sub-visible' because they can't be detected using only visible light. MODIS' 1.38um channel detects electromagnetic radiation in the infrared region of the spectrum. These images were made from data collected on April 4, 2000. Image courtesy Mark Gray, MODIS Atmosphere Team

2002-01-01

390

Cloud cameras at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

This thesis presents the results of measurements made by infrared cloud cameras installed at the Pierre Auger Observatory in Argentina. These cameras were used to record cloud conditions during operation of the observatory's fluorescence detectors. As cloud may affect the measurement of fluorescence from cosmic ray extensive air showers, the cloud cameras provide a record of which measurements have been interfered with by cloud. Several image processing algorithms were developed, along with a methodology for the detection of cloud within infrared images taken by the cloud cameras. A graphical user interface (GUI) was developed to expediate this, as a large number of images need to be checked for cloud. A cross-check between images recorded by three of the observatory's cloud cameras is presented, along with a comparison with independent cloud measurements made by LIDAR. Despite the cloud cameras and LIDAR observing different areas of the sky, a good agreement is observed in the measured cloud fraction between the two instruments, particularly on very clear and overcast nights. Cloud information recorded by the cloud cameras, with cloud height information measured by the LIDAR, was used to identify those extensive air showers that were obscured by clou