These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Cloud pattern prediction from geostationary meteorological satellite images for solar energy forecasting  

NASA Astrophysics Data System (ADS)

Surface solar radiation forecasting permits to predict photovoltaic plant production for a massive and safe integration of solar energy into the electric network. For short-term forecasts (intra-day), methods using images from meteorological geostationary satellites are more suitable than numerical weather prediction models. Forecast schemes consist in assessing cloud motion vectors and in extrapolating cloud patterns from a given satellite image in order to predict cloud cover state above a PV plant. Atmospheric motion vectors retrieval techniques have been studied for several decades in order to improve weather forecasts. However, solar energy forecasting requires the extraction of cloud motion vectors on a finer spatial- and time-resolution than those provided for weather forecast applications. Even if motion vector retrieval is a wide research field in image processing related topics, only block-matching techniques are operationally used for solar energy forecasts via satellite images. In this paper, we propose two motion vectors extraction methods originating from video compression techniques (correlation phase and optical flow methods). We implemented them on a 6-day dataset of Meteosat-10 satellite diurnal images. We proceeded to cloud pattern extrapolation and compared predicted cloud maps against actual ones at different time horizons from 15 minutes to 4 hours ahead. Forecast scores were compared to the state-of-the-art (block matching) method. Correlation phase methods do not outperform block-matching but their computation time is about 25 times shorter. Optical flow based method outperforms all the methods with a satisfactory time computing.

Cros, S.; Sébastien, N.; Liandrat, O.; Schmutz, N.

2014-10-01

2

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.

Dave Dempsey

2005-03-10

3

Active Imaging through Cirrus Clouds.  

PubMed

The presence of clouds of ice particles in the uplink and downlink path of an illumination beam can severely impede the performance of an active imaging system. Depending on the optical depth of the cloud, i.e., its density and depth, the beam can be completely scattered and extinguished, or the beam can pass through the cloud with some fraction attenuated, scattered, and depolarized. In particular, subvisual cirrus clouds, i.e., high, thin cirrus clouds that cannot be observed from the ground, can affect the properties and alignment of both uplink and downlink beams. This paper discusses the potential for active imaging in the presence of cirrus clouds. We document field data results from an active imaging experiment conducted several years ago, which the authors believe to show the effects of cirrus clouds on an active imaging system. To verify these conclusions, we include the results of a simulation of the interaction of a coherent illumination scheme with a cirrus cloud. PMID:19377551

Landesman, B; Kindilien, P; Pierson, R; Matson, C; Mosley, D

1997-11-24

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

Venus Cloud Patterns (colorized and filtered)  

NASA Technical Reports Server (NTRS)

This picture of Venus was taken by the Galileo spacecrafts Solid State Imaging System on February 14, 1990, at a range of almost 1.7 million miles from the planet. A highpass spatial filter has been applied in order to emphasize the smaller scale cloud features, and the rendition has been colorized to a bluish hue in order to emphasize the subtle contrasts in the cloud markings and to indicate that it was taken through a violet filter. The sulfuric acid clouds indicate considerable convective activity, in the equatorial regions of the planet to the left and downwind of the subsolar point (afternoon on Venus). They are analogous to 'fair weather clouds' on Earth. The filamentary dark features visible in the colorized image are here revealed to be composed of several dark nodules, like beads on a string, each about 60 miles across. The Galileo Project is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory; its mission is to study Jupiter and its satellites and magnetosphere after multiple gravity assist flybys at Venus and Earth. These images of the Venus clouds were taken by Galileo's Solid State Imaging System February 13, 1990, at a range of about 1 million miles. The smallest detail visible is about 20 miles. The two right images show Venus in violet light, the top one at a time six hours later than the bottom one. They show the state of the clouds near the top of Venus's cloud deck. A right to left motion of the cloud features is evident and is consistent with westward winds of about 230 mph. The two left images show Venus in near infrared light, at the same times as the two right images. Sunlight penetrates through the clouds more deeply at the near infrared wavelengths, allowing a view near the bottom of the cloud deck. The westward motion of the clouds is slower (about 150 mph) at the lower altitude. The clouds are composed of sulfuric acid droplets and occupy a range of altitudes from 30 to 45 miles. The images have been spatially filtered to bring out small scale details and de-emphasize global shading. The filtering has introduced artifacts (wiggly lines running north/south) that are faintly visible in the infrared image. The Galileo Project is managed for NASA's Office of Space Science and Applications by the Jet Propulsion Laboratory; its mission is to study Jupiter and its satellites and magnetosphere after multiple gravity assist flybys at Venus and Earth.

1990-01-01

6

Cloud computing in medical imaging.  

PubMed

Over the past century technology has played a decisive role in defining, driving, and reinventing procedures, devices, and pharmaceuticals in healthcare. Cloud computing has been introduced only recently but is already one of the major topics of discussion in research and clinical settings. The provision of extensive, easily accessible, and reconfigurable resources such as virtual systems, platforms, and applications with low service cost has caught the attention of many researchers and clinicians. Healthcare researchers are moving their efforts to the cloud, because they need adequate resources to process, store, exchange, and use large quantities of medical data. This Vision 20/20 paper addresses major questions related to the applicability of advanced cloud computing in medical imaging. The paper also considers security and ethical issues that accompany cloud computing. PMID:23822402

Kagadis, George C; Kloukinas, Christos; Moore, Kevin; Philbin, Jim; Papadimitroulas, Panagiotis; Alexakos, Christos; Nagy, Paul G; Visvikis, Dimitris; Hendee, William R

2013-07-01

7

Jupiter's Great Red Spot: Fine-scale matches of model vorticity patterns to prevailing cloud patterns  

NASA Astrophysics Data System (ADS)

We report on a set of six new matches between fine-scale features in the vorticity field of a three-dimensional (3D), primitive-equation, finite-difference model of Jupiter's Great Red Spot that includes no clouds or cloud physics, and quasi-permanent structures in reflected visible-band images of the clouds. These add to similar success by Cho et al. (Cho, J., de la Torre Juárez, M., Ingersoll, A.P., Dritschel, D.G. [2001]. J. Geophys. Res. 106, 5099-5106), who earlier captured four characteristic features of the GRS, also reproduced here, using a 3D quasi-geostrophic, cloud-free contour-dynamics model. In that study and this, the key enabling model attribute is sufficient horizontal resolution, rather than the moist-convective and cloud-microphysics processes often required to match the patterns of clouds in terrestrial hurricanes. The only significant feature that these dry models do not capture is the episodic moist-convective plumes seen in the northwest quadrant adjacent to the GRS. We initialize with Jupiter's averaged zonal winds plus an approximately balanced, smooth 3D ellipsoidal anticyclone. The threshold horizontal grid-resolution to obtain the fine-scale matches is approximately ?y/Ld ? 0.15, where ?y ? 300 km is the meridional grid spacing and Ld ˜ 2000 km the Rossby deformation length. For models with this or finer horizontal resolution, the best correspondence with observations is reached after about six vortex turnaround times from initialization (˜30 Earth days), but good facsimiles of nearly all the studied features appear after only 1.5 turnaround times (˜7-8 days). We conclude that in images of Jupiter, it is not accurate to associate clouds with upward motion, since these dry models reproduce the observed cloud patterns without this association, and indeed the synoptic-scale vertical motions in the model, as well as those deduced from observations, do not at all correspond to the observed cloud patterns. Instead, Jupiter's cloud-top patterns indicate the effects of local shear in the manner of passive-tracer fields. As a corollary, the water clouds on Jupiter, which lie unseen below its visible clouds, are the only ones on the planet likely to correlate with upwelling in the manner that clouds do on Earth. The next step is to extend studies such as this past the reflected visible band, for example to include the GRS's 5-?m emission bright collar, which may require the inclusion of cloud physics to enable the successful simulation of large voids.

Morales-Juberías, Raúl; Dowling, Timothy E.

2013-07-01

8

Pattern recognition of satellite cloud imagery for improved weather prediction  

NASA Technical Reports Server (NTRS)

The major accomplishment was the successful development of a method for extracting time derivative information from geostationary meteorological satellite imagery. This research is a proof-of-concept study which demonstrates the feasibility of using pattern recognition techniques and a statistical cloud classification method to estimate time rate of change of large-scale meteorological fields from remote sensing data. The cloud classification methodology is based on typical shape function analysis of parameter sets characterizing the cloud fields. The three specific technical objectives, all of which were successfully achieved, are as follows: develop and test a cloud classification technique based on pattern recognition methods, suitable for the analysis of visible and infrared geostationary satellite VISSR imagery; develop and test a methodology for intercomparing successive images using the cloud classification technique, so as to obtain estimates of the time rate of change of meteorological fields; and implement this technique in a testbed system incorporating an interactive graphics terminal to determine the feasibility of extracting time derivative information suitable for comparison with numerical weather prediction products.

Gautier, Catherine; Somerville, Richard C. J.; Volfson, Leonid B.

1986-01-01

9

Retrieval algorithms for cloud motion from ground-based images  

NASA Astrophysics Data System (ADS)

We present the preliminary results of a project, focused on obtaining information about the velocity and direction of motion of air masses by means of ground-based measurements of visible cloud motion. This information can be used in short-term local weather forecast and is helpful in studies of the dynamics of the physical processes in clouds. We report the recent progress in the development of algorithms and tools for retrieving the three-dimensional field of vectors of velocity of cloud motion from time series of ground-based digital images. The visible motion of a cloud is the compound effect of the translational drift of the cloud as a whole with the velocity of the adjacent air masses, and of deformations due to the physical processes in the atmosphere. Because of the continuous changes of shape, extracting the translational component in the displacement of a cloud from a series of consecutive images is a highly non-trivial problem. Our approach consists in selecting a set of characteristic reference patterns of the cloud on the first image of the series, tracking them on the subsequent images, and evaluating this way the individual displacement of each reference pattern. Specific algorithms are being developed for the optimal choice of the reference patterns on the starting image and the recognition of these patterns on the subsequent images, depending on the type of the observed cloud. For clouds with low contrast or no edges, such as Stratus, Nimbostratus and Stratocumulus, implementations of the Optical Flow method are under development. For clouds with distinct contours, such as Cumulus and Altocumulus, the edges are decomposed into one-dimensional curvilinear patterns. To reduce the uncertainties, a multi-parametric model of the transformations of the cloud shape between images is defined next which, besides parallel transport, also involves dilatation, rotation, and possibly some local deformations. The parameters of the model are calculated from the individual displacements of the patterns by a least-square fit. What is obtained this way is a smooth approximation to the two-dimensional field of angular velocities of the cloud surface as seen from the observer's position. The three-dimensional vectors of velocity of the cloud are calculated by combining the results of multiple synchronous observations from distant sites. Prior to be put together, the data from different observers are corrected for optical distortion. We analyse the various sources of uncertainty of the calculated velocities of air masses, related to inaccuracy of the digital images, to identification errors in tracking the reference patterns on the series of images and to triangulation. We show that external telemetric information about the distance to the observed clouds may reduce the uncertainty of the results. We also discuss the optimal choice of the time interval between consecutive images as a compromise between the increasing requirements for computational power and the higher efficiency of the pattern recognition methods at shorter time intervals. The work is partially supported by the Bulgarian NFSR under contract NZ-1414/04.

Bakalova, Kalinka

10

CEDIMS: cloud ethical DICOM image Mojette storage  

NASA Astrophysics Data System (ADS)

Dicom images of patients will necessarily been stored in Clouds. However, ethical constraints must apply. In this paper, a method which provides the two following conditions is presented: 1) the medical information is not readable by the cloud owner since it is distributed along several clouds 2) the medical information can be retrieved from any sufficient subset of clouds In order to obtain this result in a real time processing, the Mojette transform is used. This paper reviews the interesting features of the Mojette transform in terms of information theory. Since only portions of the original Dicom files are stored into each cloud, their contents are not reachable. For instance, we use 4 different public clouds to save 4 different projections of each file, with the additional condition that any 3 over 4 projections are enough to reconstruct the original file. Thus, even if a cloud is unavailable when the user wants to load a Dicom file, the other 3 are giving enough information for real time reconstruction. The paper presents an implementation on 3 actual clouds. For ethical reasons, we use a Dicom image spreaded over 3 public clouds to show the obtained confidentiality and possible real time recovery.

Guédon, Jeanpierre; Evenou, Pierre; Tervé, Pierre; David, Sylvain; Béranger, Jérome

2012-02-01

11

Cloud masking of multitemporal remote sensing images  

NASA Astrophysics Data System (ADS)

An automatic cloud masking is one of the first required processing steps since the operational use of satellite image time series might be hampered by undetected clouds. The high temporal revisit of current and forthcoming missions allows us to consider cloud screening as an unsupervised change detection problem in the temporal domain. Therefore, we propose a cloud screening method based on detecting abrupt changes in the temporal domain. The main assumption is that image time series follow smooth variations over land (background) and abrupt changes in certain spectral and spatial features will be mainly due to the presence of clouds. The method estimates the background and common surface changes using the full information in the time series. In particular, we propose linear and nonlinear least squares regression algorithms that minimize both the prediction and estimation error simultaneously. Then, significant differences in the image of interest with respect to the estimated background are identified as clouds. The use of kernel methods allows the generalization of the algorithm to account for higher-order (nonlinear) feature relations. After cloud detection, cloud-free time series at high spatial resolution can be used to obtain a better monitoring of the land cover dynamics and to generate more elaborated products. The proposed method is tested in a dataset with 5-day revisit time series from SPOT-4 at high resolution and Landsat-8 time series.

Gómez-Chova, L.; Amorós-López, J.; Muñoz-Marí, J.; Camps-Valls, G.

2014-10-01

12

Imaging patterns in melioidosis.  

PubMed

Melioidosis is an infectious disease caused by Pseudomonas pseudomallei. It is seldom diagnosed promptly and, if untreated, can lead to an 80-100% mortality rate. Twenty-eight patients with melioidosis were identified over a 6 year period, and their imaging patterns were analysed. Respiratory infections were the commonest form of presentation, frequently shown as diffuse airspace consolidation, and accounted for the highest mortality. Visceral and musculoskeletal infections were associated with chronicity and a high relapse rate. Multifocal splenic abscesses were a common occurrence. Septic arthritis of the knee was frequently seen. The majority of patients had diabetes mellitus and chronic ill-health. An increased awareness of the disease can contribute to its early detection and appropriate treatment. PMID:7487762

Tan, A P; Pui, M H; Tan, L K

1995-08-01

13

Soviet image pattern recognition research  

Microsoft Academic Search

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

B. L. McKenney; M. McGrain; A. Klinger; J. K. Aggarwal; N. J. George; R. M. Haralick

1989-01-01

14

Male pattern baldness (image)  

MedlinePLUS

Male pattern baldness is a sex-linked characteristic that is passed from mother to child. A man can more accurately predict his chances of developing male pattern baldness by observing his mother's father than by looking ...

15

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

16

Spatial and Temporal Patterns of Aerosol-Cloud Interactions  

NASA Astrophysics Data System (ADS)

This study determines the spatial and temporal distribution of regions with frequent aerosol-cloud interactions (aci) and identifies their meteorological determinants based on CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations) and ECMWF (European Centre for Medium-Range Weather Forecasts) data products. Atmospheric aerosols influence the microphysical structure of clouds, while both also respond to meteorological conditions. The potential radiative adjustments to changes in a cloud system associated with aerosol-cloud interactions are grouped and termed as effective radiative forcing due to aerosol-cloud interactions (ERFaci). It is difficult to distinguish, to what extent radiative forcing and precipitation patterns of clouds are a result of cloud feedbacks to aerosols or the existing meteorological conditions. A complete understanding of aerosol-cloud-meteorology interactions is crucial as the uncertainty range of ERFaci in climate change modeling could be significantly reduced. In the present study it is suggested that presence of hydrated aerosols is an implication for aci. Knowledge of their vertical and horizontal distribution and frequency over the globe would be important for understanding ERFaci. To identify regions with aerosol-cloud transitions the CAD score (cloud-aerosol discrimination) of the CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) instrument on the CALIPSO satellite is used. It separates aerosols and clouds according to the probability distribution functions of 5 parameters (attenuated backscatter, total color ratio, volume depolarization ratio, altitude and latitude) and assigns the likelihood of cloud or aerosol presence. This parameter is used to calculate relative frequencies of aci on a global scale from 2006 to 2013.

Fuchs, Julia; Cermak, Jan

2014-05-01

17

Wavefront propagation and imaging through cirrus clouds  

NASA Astrophysics Data System (ADS)

The authors present a wavefront reconstruction technique for beams forward scattered and back scattered through cirrus clouds. The technique uses ray distributions from the Coherent Illumination and Ray Trace Imaging Software for Cirrus which traces the propagation and E field vectors through a 3D volume of ice crystals in the shape of columns, plates, bullets, and bullet rosettes with random positions and polydisperse sizes and orientations. The wavefronts are then propagated to a telescope receiver on the ground and imaged in the receiver focal plate. A modification transfer function for each of these images is calculated and compared to the MTF for a diffraction-limited system.

Landesman, Barbara T.; Kindilien, Peter; Matson, Charles L.

1999-12-01

18

Pattern recognition analysis of polar clouds during summer and winter  

NASA Technical Reports Server (NTRS)

A pattern recognition algorithm is demonstrated which classifies eighteen surface and cloud types in high-latitude AVHRR imagery based on several spectral and textural features, then estimates the cloud properties (fractional coverage, albedo, and brightness temperature) using a hybrid histogram and spatial coherence technique. The summertime version of the algorithm uses both visible and infrared data (AVHRR channels 1-4), while the wintertime version uses only infrared data (AVHRR channels 3-5). Three days of low-resolution AVHRR imagery from the Arctic and Antarctic during January and July 1984 were analyzed for cloud type and fractional coverage. The analysis showed significant amounts of high cloudiness in the Arctic during one day in winter. The Antarctic summer scene was characterized by heavy cloud cover in the southern ocean and relatively clear conditions in the continental interior. A large region of extremely low brightness temperatures in East Antarctica during winter suggests the presence of polar stratospheric cloud.

Ebert, Elizabeth E.

1992-01-01

19

NIR: Content based image retrieval on cloud computing  

Microsoft Academic Search

NIR is an open source cloud computing enabled content based image retrieval system. With the development and popularization of cloud computing, more and more researchers from different research areas do research with the help of cloud computing. Nowadays content based image retrieval as one of the challenging and emerging technologies is high computation task because of the algorithm computation complexity

Zhuo Yang; Sei-ichiro KAMATA; Alireza AHRARY

2009-01-01

20

Analysis of Tropical Ice Cloud Spatial and Temporal Patterns  

Microsoft Academic Search

The Moderate-resolution Imaging Spectroradiometers (MODIS) on NASA's Terra and Aqua platforms offer valuable observations of the earth and its atmosphere, facilitating significant research in the atmospheric sciences. Specifically, the implementation of the 1.375-mum water vapor absorption band allows for exclusive investigations of ice clouds (e.g., cirrus clouds). In this study, we perform an analysis of the spatial and temporal trends

K. Meyer; P. Yang; G. North; B. Gao

2005-01-01

21

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

22

Clouds  

NSDL National Science Digital Library

First, the Project Atmosphere Canada offers a module to educate primary and secondary students about cloud formation and characteristics (1). The website outlines key points and offers a more in-depth discussion of water vapor, cloud formation, convection, air motion, severe weather, and more. The second website, by Scholastic, supplies many pdf documents of activities and lesson plans for all types of weather phenomena including clouds (2). Students can learn about condensation, discover what makes up a cloud, and find a key identifying the cloud types. Next, USA Today offers an online tutorial of the differing characteristics of clouds (3). Users can learn about Mammatus clouds, contrails, cloud seeding, and other cloud-related topics. At the fourth website, visitors can view meteorologist Dan Satterfield's amazing cloud photographs (4). Educators may find useful materials to supplement their lectures. Next, NASA's Climate and Radiation Branch furnishes "information on the fantastic variety of cloud forms and structures, and their implications for climate" (5). While the website is still being constructed, users can find useful information about the Bounded Cascades Fractal Cloud model, animations, and definitions of inhomogeneous cloud terminology. The sixth website, created by the National Center for Atmospheric Research and the University Corporation for Atmospheric Research, addresses how clouds impact our lives, how they cause chaos, and how they form (6). The enlightening descriptions are packed with colorful images and short quizzes. Next, The Australian Government's Bureau of Meteorology describes the useful of clouds as an indicator of weather conditions (7). After learning how moist air can form clouds, individuals can view images of the ten most common cloud types. Lastly, Enchanted Learning offers a table of the cloud types with their abbreviation, appearance, composition, and altitude along with explanations of cloud formation and the atmosphere (8). Educators can find simple activities dealing with cloud types and the water cycle.

23

Solid Image Extraction from LIDAR Point Clouds  

NASA Astrophysics Data System (ADS)

In laser scanner architectural surveying it is necessary to extract orthogonal projections from the tridimensional model, plans, elevations and cross sections. The paper presents the workflow of architectural drawings production from laser scans, focusing on the orthogonal projection of the point cloud on solid images, in order to avoid the time consuming surface modeling, when it is not strictly necessary. The proposed procedures have been implemented in fortran90 and included in the VELOCE software package, then tested and applied to the case study of the San Pietro church in Porto Venere (SP), integrating the architectural surveying with an existing bathymetric and coastal surveying.

Munaretto, D.; Roggero, M.

2013-02-01

24

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

25

Capturing and analyzing wheelchair maneuvering patterns with mobile cloud computing.  

PubMed

Power wheelchairs have been widely used to provide independent mobility to people with disabilities. Despite great advancements in power wheelchair technology, research shows that wheelchair related accidents occur frequently. To ensure safe maneuverability, capturing wheelchair maneuvering patterns is fundamental to enable other research, such as safe robotic assistance for wheelchair users. In this study, we propose to record, store, and analyze wheelchair maneuvering data by means of mobile cloud computing. Specifically, the accelerometer and gyroscope sensors in smart phones are used to record wheelchair maneuvering data in real-time. Then, the recorded data are periodically transmitted to the cloud for storage and analysis. The analyzed results are then made available to various types of users, such as mobile phone users, traditional desktop users, etc. The combination of mobile computing and cloud computing leverages the advantages of both techniques and extends the smart phone's capabilities of computing and data storage via the Internet. We performed a case study to implement the mobile cloud computing framework using Android smart phones and Google App Engine, a popular cloud computing platform. Experimental results demonstrated the feasibility of the proposed mobile cloud computing framework. PMID:24110214

Fu, Jicheng; Hao, Wei; White, Travis; Yan, Yuqing; Jones, Maria; Jan, Yih-Kuen

2013-01-01

26

CO Imaging of Molecular Clouds with Optical HII Regions  

Microsoft Academic Search

(12) CO and (13) CO J=1-0 images of molecular clouds associated with the optical HII regions S140, S155, and S235 made with the FCRAO 15 beam array receiver are presented. These images reveal a complex environment resulting from the interaction of the HII regions with the ambient cloud material. Cloud properties are compared to those derived from surveys of the

M. H. Heyer; J. Carpenter; E. F. Ladd

1993-01-01

27

Retrieving the Velocity of Motion of Air Masses from Digital Images of Clouds  

NASA Astrophysics Data System (ADS)

An interdisciplinary project, aimed at developing tools for the determination of physical characteristics of the atmosphere by means of ground-based digital imaging in the visible range is in progress. Determining the 3-dimensional field of velocities of motion of the air masses from digital images of clouds is among the central tasks. The approach consists in identifying patterns of the cloud structure with characteristic shape and measuring their angular displacement by tracking them in series of consecutive digital images, taken at optimal time intervals. The geometrical mapping of the cloud of an image onto the following image (including translation, rotation, dilatation and additional small irregular deformations) is parameterized, and the numerical values of the parameters are computed by minimizing the sum over pixels of the squared deviation of the brightness, weighed with factors accounting for the representativeness of the group of pixels, and with constrains on the parameters describing irregular deformations.

Bakalova, Kalinka; Bakalov, Dimitar

2007-04-01

28

CO Imaging of Molecular Clouds with Optical HII Regions  

NASA Astrophysics Data System (ADS)

(12) CO and (13) CO J=1-0 images of molecular clouds associated with the optical HII regions S140, S155, and S235 made with the FCRAO 15 beam array receiver are presented. These images reveal a complex environment resulting from the interaction of the HII regions with the ambient cloud material. Cloud properties are compared to those derived from surveys of the Galactic Plane and other imaging studies of the molecular interstellar medium. These images emphasize that most of the kinetic energy is contained within the clump to clump motions on size scales greater than several pc.

Heyer, M. H.; Carpenter, J.; Ladd, E. F.

1993-12-01

29

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

30

Development of a sky imager for cloud cover assessment.  

PubMed

Based on a CCD camera, we have developed an in-house sky imager system for the purpose of cloud cover estimation and characterization. The system captures a multispectral image every 5 min, and the analysis is done with a method based on an optimized neural network classification procedure and a genetic algorithm. The method discriminates between clear sky and two cloud classes: opaque and thin clouds. It also divides the image into sectors and finds the percentage of clouds in those different regions. We have validated the classification algorithm on two levels: image level, using the cloud observations included in the METAR register performed at the closest meteorological station, and pixel level, determining whether the final classification is correct. PMID:18157209

Cazorla, A; Olmo, F J; Alados-Arboledas, L

2008-01-01

31

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

32

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

33

Female-pattern baldness (image)  

MedlinePLUS

Female-pattern baldness is a pattern of hair loss (alopecia) caused by hormones, aging and genetics. Unlike male-pattern baldness, female-pattern baldness is an over-all thinning which maintains the normal ...

34

Mesopause Horizontal wind estimates based on AIM CIPS polar mesospheric cloud pattern matching  

NASA Astrophysics Data System (ADS)

A cloud pattern matching approach is used to estimate horizontal winds in the mesopause region using Polar Mesospheric Cloud (PMC) albedo data measured by the Cloud Imaging and Particle Size instrument on the AIM satellite. Measurements for all 15 orbits per day throughout July 2007 are used to achieve statistical significance. For each orbit, eighteen out of the twenty-seven scenes are used for the pattern matching operation. Some scenes at the lower latitudes are not included because there is barely any cloud coverage for these scenes. The frame-size chosen is about 12 degrees in longitude and 3 degrees in latitude. There is no strict criterion in choosing the frame size since PMCs are widespread in the polar region and most local patterns do not have a clearly defined boundary. The frame moves at a step of 1/6th of the frame size in both the longitudinal and latitudinal directions to achieve as many 'snap-shots' as possible. A 70% correlation is used as a criterion to define an acceptable match between two patterns at two time frames; in this case the time difference is about 3.6 minutes that spans every 5 'bowtie' scenes. A 70% criterion appears weak if the chosen pattern is expected to act like a tracer. It is known that PMC brightness varies rapidly with a changing temperature and water vapor environment or changing nucleation conditions, especially on smaller spatial scales; therefore PMC patterns are not ideal tracers. Nevertheless, within a short time span such as 3.6 minutes a 70% correlation is sufficient to identify two cloud patterns that come from the same source region, although the two patterns may exhibit a significant difference in the actual brightness. Analysis of a large number of matched cloud patterns indicates that over the 3.6-minute time span about 70% of the patterns remain in the same locations. Given the 25-km2 horizontal resolution of CIPS data, this suggests that the overall magnitude of horizontal wind at PMC altitudes (~80-87 km) in the polar summer cannot exceed 25 m/s. In other words, the wind detection resolution is no better than 25 m/s. There are about 10% of cases in which it appears that an easterly prevails, with a peak value at about 80-100m/s. In another 5% of cases a westerly appears to prevail. The remaining 15% cases are related to either invalid cloud features with poor background correction or the situation in which the matching occurs at the corners of the bowties. The AIM CIPS cloud pattern matching results overall suggest that higher wind speed (25-200 m/s) can be reached occasionally, while in a majority of cases the wind advection caused albedo change is much smaller than the in-situ albedo change. However, we must note that this analysis was a feasibility study and the short period analyzed may not be representative of the winds over a seasonal time scale or the multiple-year average.

Rong, P.; Yue, J.; Russell, J. M.; Gong, J.; Wu, D. L.; Randall, C. E.

2013-12-01

35

Image to Point Cloud Method of 3D-MODELING  

NASA Astrophysics Data System (ADS)

This article describes the method of constructing 3D models of objects (buildings, monuments) based on digital images and a point cloud obtained by terrestrial laser scanner. The first step is the automated determination of exterior orientation parameters of digital image. We have to find the corresponding points of the image and point cloud to provide this operation. Before the corresponding points searching quasi image of point cloud is generated. After that SIFT algorithm is applied to quasi image and real image. SIFT algorithm allows to find corresponding points. Exterior orientation parameters of image are calculated from corresponding points. The second step is construction of the vector object model. Vectorization is performed by operator of PC in an interactive mode using single image. Spatial coordinates of the model are calculated automatically by cloud points. In addition, there is automatic edge detection with interactive editing available. Edge detection is performed on point cloud and on image with subsequent identification of correct edges. Experimental studies of the method have demonstrated its efficiency in case of building facade modeling.

Chibunichev, A. G.; Galakhov, V. P.

2012-07-01

36

Image transfer through cirrus clouds. II. Wave-front segmentation and imaging.  

PubMed

A hybrid technique to simulate the imaging of space-based objects through cirrus clouds is presented. The method makes use of standard Huygens-Fresnel propagation beyond the cloud boundary and a novel vector trace approach within the cloud. At the top of the cloud, the wave front is divided into an array of input gradient vectors, which are in turn transmitted through the cloud model by use of the Coherent Illumination Ray Trace and Imaging Software for Cirrus. At the bottom of the cloud, the output vector distribution is used to reconstruct a wave front that continues propagating to the ground receiver. Images of the object as seen through cirrus clouds with different optical depths are compared with a diffraction-limited image. Turbulence effects from the atmospheric propagation are not included. PMID:12510928

Landesman, Barbara T; Matson, Charles L

2002-12-20

37

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 Earth’s 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.

2012-08-03

38

Gas cloud infrared image enhancement based on anisotropic diffusion  

NASA Astrophysics Data System (ADS)

Leakage of dangerous gases will not only pollute the environment, but also seriously threat public safety. Thermal infrared imaging has been proved to be an efficient method to qualitatively detect the gas leakage. But some problems are remained, especially when monitoring the leakage in a passive way. For example, the signal is weak and the edge of gas cloud in the infrared image is not obvious enough. However, we notice some important characteristics of the gas plume and therefore propose a gas cloud infrared image enhancement method based on anisotropic diffusion. As the gas plume presents a large gas cloud in the image and the gray value is even inside the cloud, strong forward diffusion will be used to reduce the noise and to expand the range of the gas cloud. Frames subtraction and K-means cluttering pop out the gas cloud area. Forward-and-Backward diffusion is to protect background details. Additionally, the best iteration times and the time step parameters are researched. Results show that the gas cloud can be marked correctly and enhanced by black or false color, and so potentially increase the possibility of gas leakage detection.

Li, Jiakun; Wang, Lingxue; Zhang, Changxing; Long, Yunting; Zhang, Bei

2011-05-01

39

Concentric gravity waves in polar mesospheric clouds from the Cloud Imaging and Particle Size experiment  

NASA Astrophysics Data System (ADS)

Five concentric atmospheric gravity wave (AGW) events have been identified in Polar Mesospheric Cloud (PMC) images of the summer mesopause region (~82-84 km) made by the Cloud Imaging and Particle Size (CIPS) instrument on board the Aeronomy of Ice in the Mesosphere satellite during the Northern Hemisphere 2007 and 2009 PMC seasons. The AGWs modulate the PMC albedo, ice water content, and particle size, creating concentric ring patterns. On only one occasion (13 July 2007), the concentric AGWs in PMCs were aligned with AGWs with similar shapes observed in 4.3 µm radiance in the lower stratosphere, as measured by Atmospheric Infrared Sounder (AIRS). Coincident AIRS and Infrared Atmospheric Sounding Interferometer nadir measurements of 8.1 µm radiance reveal a region of deep convection in the troposphere close to the estimated centers of the AGWs in the stratosphere, strongly suggesting that convection is the wave source. The AGWs in CIPS on 13 July 2007 were ~1000 km away from the observed deep convection. Three other concentric AGWs in PMCs were 500-1000 km away from deep convection in the troposphere, while no convection was observed related to the wave on 29 July 2009. We perform a 2-D ray tracing study for the AGW event on 13 July 2007. The calculated propagation distance is much shorter than the distance between the AGWs in PMCs and the observed convection. The 2-D ray tracing study indicates that the AGWs in PMCs and in the stratosphere are probably excited by different tropospheric convective systems.

Yue, Jia; Thurairajah, Brentha; Hoffmann, Lars; Alexander, Joan; Chandran, Amal; Taylor, Michael J.; Russell, James M.; Randall, Cora E.; Bailey, Scott M.

2014-05-01

40

Image Recognition Based on Biometric Pattern Recognition  

Microsoft Academic Search

A new method, biomimetric pattern recognition, is mentioned to recognize images. At first, the image is pretreatment and feature extraction, then a high vector is got. A biomimetric pattern recognition model is designed. The judgment function is used to discriminate the classification of the samples. It is showed that the method is effective for little samples by experiment. It would

Shuliang Sun; Zhong Chen; Chenglian Liu; Yongning Guo; Xueyun Lin

2011-01-01

41

Generating image descriptions using dependency relational patterns  

E-print Network

This paper presents a novel approach to automatic captioning of geo-tagged images by summarizing multiple webdocuments that contain information related to an image’s location. The summarizer is biased by dependency pattern models towards sentences which contain features typically provided for different scene types such as those of churches, bridges, etc. Our results show that summaries biased by dependency pattern models lead to significantly higher ROUGE scores than both n-gram language models reported in previous work and also Wikipedia baseline summaries. Summaries generated using dependency patterns also lead to more readable summaries than those generated without dependency patterns. 1

Ahmet Aker; Robert Gaizauskas

42

Automatic cloud coverage assessment of Formosat-2 image  

NASA Astrophysics Data System (ADS)

Formosat-2 satellite equips with the high-spatial-resolution (2m ground sampling distance) remote sensing instrument. It has been being operated on the daily-revisiting mission orbit by National Space organization (NSPO) of Taiwan since May 21 2004. NSPO has also serving as one of the ground receiving stations for daily processing the received Formosat- 2 images. The current cloud coverage assessment of Formosat-2 image for NSPO Image Processing System generally consists of two major steps. Firstly, an un-supervised K-means method is used for automatically estimating the cloud statistic of Formosat-2 image. Secondly, manual estimation of cloud coverage from Formosat-2 image is processed by manual examination. Apparently, a more accurate Automatic Cloud Coverage Assessment (ACCA) method certainly increases the efficiency of processing step 2 with a good prediction of cloud statistic. In this paper, mainly based on the research results from Chang et al, Irish, and Gotoh, we propose a modified Formosat-2 ACCA method which considered pre-processing and post-processing analysis. For pre-processing analysis, cloud statistic is determined by using un-supervised K-means classification, Sobel's method, Otsu's method, non-cloudy pixels reexamination, and cross-band filter method. Box-Counting fractal method is considered as a post-processing tool to double check the results of pre-processing analysis for increasing the efficiency of manual examination.

Hsu, Kuo-Hsien

2011-11-01

43

An enhanced neighborhood similar pixel interpolator approach for removing thick clouds in landsat images  

Technology Transfer Automated Retrieval System (TEKTRAN)

Thick cloud contaminations in Landsat images limit their regular usage for land applications. A few methods have been developed to remove thick clouds using additional cloud-free images. Unfortunately, the cloud-free composition image produced by existing methods commonly lacks from the desired spat...

44

A holistic image segmentation framework for cloud detection and extraction  

NASA Astrophysics Data System (ADS)

Atmospheric clouds are commonly encountered phenomena affecting visual tracking from air-borne or space-borne sensors. Generally clouds are difficult to detect and extract because they are complex in shape and interact with sunlight in a complex fashion. In this paper, we propose a clustering game theoretic image segmentation based approach to identify, extract, and patch clouds. In our framework, the first step is to decompose a given image containing clouds. The problem of image segmentation is considered as a "clustering game". Within this context, the notion of a cluster is equivalent to a classical equilibrium concept from game theory, as the game equilibrium reflects both the internal and external (e.g., two-player) cluster conditions. To obtain the evolutionary stable strategies, we explore three evolutionary dynamics: fictitious play, replicator dynamics, and infection and immunization dynamics (InImDyn). Secondly, we use the boundary and shape features to refine the cloud segments. This step can lower the false alarm rate. In the third step, we remove the detected clouds and patch the empty spots by performing background recovery. We demonstrate our cloud detection framework on a video clip provides supportive results.

Shen, Dan; Xu, Haotian; Blasch, Erik; Horvath, Gregory; Pham, Khanh; Zheng, Yufeng; Ling, Haibin; Chen, Genshe

2013-05-01

45

BUILD UP OF ELECTRON CLOUD WITH DIFFERENT BUNCH PATTERN IN THE PRESENCE OF SOLENOID FIELD  

E-print Network

the wall of the vac- uum chamber and therefore reduces the cloud density near the positron beam. AllBUILD UP OF ELECTRON CLOUD WITH DIFFERENT BUNCH PATTERN IN THE PRESENCE OF SOLENOID FIELD Yunhai of electron cloud due to electron multipacting in the PEP-II positron ring. We find that the distribution

Furman, Miguel

46

HI Imaging of the Large Magellanic Cloud  

E-print Network

We present results from the combined Australia Telescope Compact Array (ATCA) aperture synthesis mosaic survey of HI emission in the Large Magellanic Cloud with 64m Parkes single dish telescope observations.

S. Kim; L. Staveley-Smith; R. J. Sault

2000-09-19

47

Skin lesions image analysis utilizing smartphones and cloud platforms.  

PubMed

This chapter presents the state of the art on mobile teledermoscopy applications, utilizing smartphones able to store digital images of skin areas depicting regions of interest (lesions) and perform self-assessment or communicate the captured images with expert physicians. Mobile teledermoscopy systems consist of a mobile application that can acquire and identify moles in skin images and classify them according their severity and Cloud infrastructure exploiting computational and storage resources. The chapter presents some indicative mobile applications for skin lesions assessment and describes a proposed system developed by our team that can perform skin lesion evaluation both on the phone and on the Cloud, depending on the network availability. PMID:25626556

Doukas, Charalampos; Stagkopoulos, Paris; Maglogiannis, Ilias

2015-01-01

48

Space Shuttle Video Images: An Example of Warm Cloud Lightning  

NASA Technical Reports Server (NTRS)

Warm cloud lightning has been reported in several tropical locations. We have been using the intensified monochrome TV cameras at night during a number of shuttle flights to observe large active thunderstorms and their associated lightning. During a nighttime orbital pass of the STS-70 mission on 17 July 1995 at 07:57:42 GMT, the controllers obtained video imagery of a small cloud that was producing lightning. Data from a GOES infrared image establishes that the cloud top had a temperature of about 271 degrees Kelvin ( -2 degrees Celsius). Since this cloud was electrified to the extent that a lightning discharge did occur, it may be another case of lightning in a cloud that presents little if any evidence of frozen or melting precipitation.

Vaughan, Otha H., Jr.; Boeck, William L.

1998-01-01

49

MY NASA DATA: Patterns in High Cloud Coverage  

NSDL National Science Digital Library

In this data analysis activity, Students will plot and analyze a time series of data for high cloud coverage from a specified location (home or school) and determine whether or not a seasonal pattern exists. The lesson includes step-by-step instructions for use of the MY NASA DATA Live Access Server (LAS), guiding students through selection of a data set from a location of their choice, importing the data into a spreadsheet, creating graphs, and analyzing data plots. The lesson provides detailed procedures, related links and sample graphs, follow-up questions, extensions, and teacher notes. Designed for student use, MY NASA DATA LAS samples micro datasets from large scientific data archives, and provides structured investigations engaging students in exploration of real data to answer real world questions.

50

The Radiative Consistency of Atmospheric Infrared Sounder and Moderate Resolution Imaging Spectroradiometer Cloud Retrievals  

NASA Technical Reports Server (NTRS)

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 of view (FOV) contributions from TC and surface temperature (TS), weighted by f and 1-f, respectively. AIRS reports up to two cloud layers while MODIS reports up to one. However, MODIS reports TC, TS, and f at a higher spatial resolution than AIRS. As a result, pixel-scale comparisons of TC and f are difficult to interpret, demonstrating the need for alternatives such as Tb,e. AIRS-MODIS Tb,e differences ((Delta)Tb,e) for identical observing scenes are useful as a diagnostic for cloud quantity comparisons. The smallest values of DTb,e are for high and opaque clouds, with increasing scatter in (Delta)Tb,e for clouds of smaller opacity and lower altitude. A persistent positive bias in DTb,e is observed in warmer and low-latitude scenes, characterized by a mixture of MODIS CO2 slicing and 11-mm window retrievals. These scenes contain heterogeneous cloud cover, including mixtures of multilayered cloudiness and misplaced MODIS cloud top pressure. The spatial patterns of (Delta)Tb,e are systematic and do not correlate well with collocated AIRS-MODIS radiance differences, which are more random in nature and smaller in magnitude than (Delta)Tb,e. This suggests that the observed inconsistencies in AIRS and MODIS cloud fields are dominated by retrieval algorithm differences, instead of differences in the observed radiances. The results presented here have implications for the validation of cloudy satellite retrieval algorithms, and use of cloud products in quantitative analyses.

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

2007-01-01

51

Conjecture on imminent earthquake prediction --- from shaving foam to cloud patterns  

E-print Network

A conjecture on imminent earthquake prediction is presented. Drastic geological deformations of crustal rock strata taking place immediately (hours/days) before an earthquake may cause fast air or gas emission/absorption vertically in between ground and sky. I conjecture, inspired by an observation of strange patterns appearing on shaving foam, that this fast movement of air fluid may produce unusual cloud patterns at interfaces between atmosphere levels. This air movement is vertical and drastic, different from the horizontal and moderate meteorological air movement, hence its caused cloud patterns are expected to be different from meteorological cloud patterns. This provides a possible origin for the so-called earthquake cloud. Recognition of different earthquake cloud patterns may provide a practical way to estimate location, magnitude and strength of geological deformations of rock strata, and hence a method with support of physics for imminent earthquake prediction. In the end of this paper an experiment...

Liu, Xin

2013-01-01

52

IRAC Imaging of Star-Cloud Collisions in the Pleiades  

NASA Astrophysics Data System (ADS)

The blue Palomar sky survey plate of the Pleiades region provides clear evidence that there is considerable dust close to the bright stars of the Pleiades. However, the network of dust filaments does not provide any unambiguous signpost for the kinematics of the dust (and gas). Radial velocity measures of interstellar absorption lines towards the bright Pleiades stars indicates that the gas is moving towards the Pleiades at a relative velocity of about 10 km/s, indicating that the gas/dust are not resident in the Pleiades but are instead transiting through the cluster. White & Bally (1993) concluded that the Pleiades was impacting the cloud from the East - and leaving a wake behind, visible in the IRAS 60 and 100 micron images of the region. Herbig & Simon (2001) imaged the brightest portion of the Merope nebula with HST, and concluded that the shape of the nebula could only be explained by the gas impacting the Pleiades from the south-southeast. Their conclusion was that the transiting cloud was an outlyer from the Taurus molecular cloud. The two explanations are not consistent. As part of a GTO program, we have obtained shallow IRAC imaging of the center of the Pleiades and have identified two stars which appear to be impacting cloud condensations at the current epoch, with extended circumstellar dust prominent at 8 um. An additional star with similar characteristics has been identified from FEPS data. A or F stars impacting moderate-density clouds should carve paraboloidal cavities in the cloud (Artymowicz and Clampin 1997), with the detailed shape of the cavity rim indicating the direction of relative motion of the star and gas. We propose deep IRAC imaging of the three stars impacting the passing cloud in order to define better the shape of their extended emission, and hence determine the motion of the gas and dust relative to the Pleiades stars.

Fazio, Giovanni; Stauffer, John; Lowrance, Patrick; Rebull, Luisa M.; Song, Inseok

2008-03-01

53

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

54

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.

55

Cloud screening Coastal Zone Color Scanner images using channel 5  

NASA Technical Reports Server (NTRS)

Clouds are removed from Coastal Zone Color Scanner (CZCS) data using channel 5. Instrumentation problems require pre-processing of channel 5 before an intelligent cloud-screening algorithm can be used. For example, at intervals of about 16 lines, the sensor records anomalously low radiances. Moreover, the calibration equation yields negative radiances when the sensor records zero counts, and pixels corrupted by electronic overshoot must also be excluded. The remaining pixels may then be used in conjunction with the procedure of Simpson and Humphrey to determine the CZCS cloud mask. These results plus in situ observations of phytoplankton pigment concentration show that pre-processing and proper cloud-screening of CZCS data are necessary for accurate satellite-derived pigment concentrations. This is especially true in the coastal margins, where pigment content is high and image distortion associated with electronic overshoot is also present. The pre-processing algorithm is critical to obtaining accurate global estimates of pigment from spacecraft data.

Eckstein, B. A.; Simpson, J. J.

1991-01-01

56

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

57

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 ...

Dorothea Ivanova

58

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

59

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

60

Direct observation of cloud forcing by ground-based thermal imaging  

NASA Astrophysics Data System (ADS)

Instantaneous surface Cloud Radiative Forcing (CRF) in the 7.5-13 ?m region is observed for the first time, using a thermal infrared camera. The sampling of clear sky and cloudy radiances from images of broken cloud fields allows cloud cover, CRF and effective cloud emission to be directly calculated, all within a consistent field of view. Analysis of 1300 images taken over more than two months in Central England shows that surface CRF is a nonlinear function of cloud cover, with daytime forcings larger and less linear than those at night. This nonlinearity is caused both by the increase in cloud optical thickness and the more frequent occurrence of low altitude (warm) cloud as the cloud cover increases. Even for nearly complete cloud cover, effective cloud emission remains significantly less than that of widely assumed homogeneous, optically thick cloud. Possible clear sky sampling errors associated with traditional methods of measuring CRF are also investigated.

Smith, Stephen; Toumi, Ralf

2008-04-01

61

Infrared cloud imaging in support of Earth-space optical communication  

E-print Network

Infrared cloud imaging in support of Earth- space optical communication Paul W. Nugent,1 Joseph A to the communication platform, so there is a need to measure spatial and temporal statistics of clouds at potential to provide continuous day-night cloud detection and classification according to the cloud optical depth

Shaw, Joseph A.

62

Forbidden coronal iron line images of Puppis A - Cloud evaporation or shocked cloud?  

NASA Astrophysics Data System (ADS)

Calibrated CCD images of the eastern X-ray knot in Puppis A, made in the forbidden red and green coronal Fe lines, are discussed. They show the high-temperature gas to have a rich morphology, with the scale of some features approaching the 2.6 arcsec resolution of the data. The pictures have been compared with an Einstein HRI soft X-ray image; there is close correspondence in the position and size of structures seen in the optical forbidden lines and in the X-rays. Located near the shock front a cloud of about 0.4 pc x 0.9 pc dimension shines brilliantly in the 5303 A line. To test the hypothesis that the cloud might be evaporating into the remnant interior, the 5303 A and 6374 A intensity distributions expected for a steady state, one-fluid evaporatig model have been computed.

Teske, Richard G.; Petre, Robert

1987-03-01

63

Neural network discrimination of subtle image patterns  

Microsoft Academic Search

A report is presented on a comparison between neural network and algorithmic classification techniques applied to a specific thermography program: the analysis of image patterns which characterize the extent of whiplash injury. Thermography recently has been reported to have clinical utility in a multitude of neuromusculoskeletal disorders. Of particular import is the application of thermography to soft-tissue injuries in which

Dwight D. Egbert; Vassilis G. Kaburlasos; Philip H. Goodman

1990-01-01

64

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

65

Color pattern selection using linguistic image scales  

NASA Astrophysics Data System (ADS)

In this paper, we propose a novel scheme to construct the color pattern retrieval system, which can recommend color patterns of the desired human feeling. The desired feeling is represented as a 9D vector in linguistic image scales. That means a component value of the vector is the degree of the feeling in the corresponding linguistic image scale. Then the system recommends color patterns of desired feeling after it compares the given query vector with emotional features of stored color patterns. In order to construct the system, the emotional features are taken from outputs of the neural network which has inputs as the physical features extracted from color patterns. To make indexing system, the hierarchical clustering method with fuzzy c-mean algorithm is used. To verify our scheme, a set of 368 color images for textile design is selected and experimented. Using the proposed retrieval scheme, we could obtain a promising results even though several problems are still remained. We believe this pilot system can be improved to find corresponding textile designs, wall papers, or pictures in a gallery for linguistic queries of human feelings.

Lee, Joon-Whoan; Um, Jinsub

1998-08-01

66

Measurement and Evaluation of Cloud free line of sight with Digital Whole Sky Imagers  

E-print Network

of the impact of clouds on airborne and ground- based laser weapon scenarios. Whole Sky Imagers (WSI) have been developed at the Marine Physical Lab for many years, for several military applications including determining evaluation of these initial results. Key words: Whole Sky Imagers, cloud, cloud free line of sight, laser

Buckingham, Michael

67

Cloud based toolbox for image analysis, processing and reconstruction tasks.  

PubMed

This chapter describes a novel way of carrying out image analysis, reconstruction and processing tasks using cloud based service provided on the Australian National eResearch Collaboration Tools and Resources (NeCTAR) infrastructure. The toolbox allows users free access to a wide range of useful blocks of functionalities (imaging functions) that can be connected together in workflows allowing creation of even more complex algorithms that can be re-run on different data sets, shared with others or additionally adjusted. The functions given are in the area of cellular imaging, advanced X-ray image analysis, computed tomography and 3D medical imaging and visualisation. The service is currently available on the website www.cloudimaging.net.au . PMID:25381109

Bednarz, Tomasz; Wang, Dadong; Arzhaeva, Yulia; Lagerstrom, Ryan; Vallotton, Pascal; Burdett, Neil; Khassapov, Alex; Szul, Piotr; Chen, Shiping; Sun, Changming; Domanski, Luke; Thompson, Darren; Gureyev, Timur; Taylor, John A

2015-01-01

68

reconstruction of high resolution ocean colour images under clouds using neuronal methods  

NASA Astrophysics Data System (ADS)

Mesoscale and sub-mesoscale phytoplankton variability significantly contributes to global primary production budgets. High-resolution modelling studies suggest that incorrect representation of mesoscale and sub-mesoscale variability in ocean global circulation models (OGCM) can result in errors of about 30% in primary production estimations. Thus, characterizing mesoscale and sub-mesoscale phytoplankton variability is important for the parameterization and validation of the OGCM. Ocean colour sensors allow a global observation of small scale chlorophyll variability patterns. However, the frequent presence of clouds in ocean colour remotely sensed imagery, prevents space and time continuity and limits its exploitation. The aim of this study is to propose a new statistical processing approach for the reconstruction of areas covered by clouds in a time sequence ocean colour images. We used a classification methodology consisting in a neural network topological map. Considering a cloud-contaminated image of the sequence, missing data are reconstructed through an unsupervised statistical process that reproduces the local spatio temporal relationships of the cloudy image. The unsupervised process is trained with a selected subset of ocean colour temporal images surrounding the cloudy images. As phytoplankton variability is partly driven by oceanic dynamics, we added a set of satellite-derived dynamic ocean products (sea surface temperature, altimetry, ocean waves) influencing strongly the phytoplankton production. To develop the under cloud reconstruction method, we began by using high resolution (about 2 Km) simulated data (output of the OPA OGCM coupled with the Lobster biogechemical model). We focused on the North Atlantic ocean which is characterized by a strong mesoscale and sub-mesoscale phytoplankton variability. When applied over two seasons(spring and winter),the method was able to reproduce the statistical characteristics of the missing data with a good accuracy. We then tried to assess the ability of the method for reconstructing high resolution real data.

Manel, J.; Thiria, S.; Lévy, M.

2009-04-01

69

Recontruction of high resolution ocean colour images under clouds using neuronal methods  

NASA Astrophysics Data System (ADS)

Mesoscale and sub-mesoscale phytoplankton variability significantly contributes to global primary production budgets. High-resolution modelling studies suggest that incorrect representation of mesoscale and sub-mesoscale variability in ocean global circulation models (OGCM) can result in errors of about 30% in primary production estimations. Thus, characterizing mesoscale and sub-mesoscale phytoplankton variability is important for the parameterization and validation of the OGCM. Ocean colour sensors allow a global observation of small scale chlorophyll variability patterns. However, the frequent presence of clouds in ocean colour remotely sensed imagery, prevents space and time continuity and limits its exploitation. The aim of this study is to propose a new statistical processing approach for the reconstruction of areas covered by clouds in a time sequence ocean colour images. We used a classification methodology consisting in a neural network topological map. Considering a cloud-contaminated image of the sequence, missing data are reconstructed through an unsupervised statistical process that reproduces the local spatio temporal relationships of the cloudy image. The unsupervised process is trained with a selected subset of ocean colour temporal images surrounding the cloudy images. As phytoplankton variability is partly driven by oceanic dynamics, we added a set of satellite-derived dynamic ocean products (sea surface temperature, altimetry, ocean waves) influencing strongly the phytoplankton production. To develop the under cloud reconstruction method, we began by using high resolution (about 2 Km) simulated data (output of the OPA OGCM coupled with the Lobster biogechemical model). We focused on the North Atlantic ocean which is characterized by a strong mesoscale and sub-mesoscale phytoplankton variability. When applied over two seasons(spring and winter),the method was able to reproduce the statistical characteristics of the missing data with a good accuracy. We then tried to assess the ability of the method for reconstructing high resolution real data.

Manel, J.; Thiria, S.; Lévy, M.

2009-04-01

70

Improved Automated Cloud Classification and Cloud Property Continuity Studies for the Visible Infrared Imager Radiometer Suite (VIIRS)  

NASA Astrophysics Data System (ADS)

A new automated cloud classification algorithm for the Visible Infrared Imager Radiometer Suite (VIIRS) is presented. The new algorithm, which is part of the Integrated Data Processing System (IDPS), builds upon the heritage Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) operational cloud top phase algorithms, and includes additional classification categories such as multi-layered clouds and cirrus. The new VIIRS algorithm is much more sensitive to optically thin cirrus than the heritage AVHRR algorithm and produces improved results at cloud edges relative to the heritage MODIS algorithm. This paper will highlight the VIIRS cloud classification algorithm enhancements. Further, in order to compare other potential VIIRS cloud algorithms against heritage MODIS and AVHRR algorithms on a global basis, a processing system called the Global Multi-imager Cloud Algorithm Testbed (GMCAT) was developed. GMCAT, which uses MODIS data, provides the capability to simultaneously run several different cloud property algorithms for the same parameter (e.g. cloud mask, cloud type, cloud top temperature, cloud optical depth, particle size). Because of the many spectral channels on the MODIS, data from it can be used to process not only MODIS algorithms, but algorithms designed for other sensors as well (e.g. VIIRS, AVHRR). This approach allows for direct comparison of products and eliminates the effects of varying field-of-views (in space and time) and instrument-related characteristics associated with standard multi-instrument comparisons. These comparison studies are also useful for accessing the characteristics of multi-instrument cloud climatologies, such as a combined AVHRR/MODIS/VIIRS climatology. Some preliminary VIIRS/AVHRR/MODIS comparisons will be shown.

Pavolonis, M. J.; Heidinger, A. K.; Hutchison, K. D.

2005-12-01

71

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

72

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

73

How the clear-sky angle of polarization pattern continues underneath clouds: full-sky measurements and implications for animal orientation.  

PubMed

One of the biologically most important parameters of the cloudy sky is the proportion P of the celestial polarization pattern available for use in animal navigation. We evaluated this parameter by measuring the polarization patterns of clear and cloudy skies using 180 degrees (full-sky) imaging polarimetry in the red (650 nm), green (550 nm) and blue (450 nm) ranges of the spectrum under clear and partly cloudy conditions. The resulting data were compared with the corresponding celestial polarization patterns calculated using the single-scattering Rayleigh model. We show convincingly that the pattern of the angle of polarization (e-vectors) in a clear sky continues underneath clouds if regions of the clouds and parts of the airspace between the clouds and the earth surface (being shady at the position of the observer) are directly lit by the sun. The scattering and polarization of direct sunlight on the cloud particles and in the air columns underneath the clouds result in the same e-vector pattern as that present in clear sky. This phenomenon can be exploited for animal navigation if the degree of polarization is higher than the perceptual threshold of the visual system, because the angle rather than the degree of polarization is the most important optical cue used in the polarization compass. Hence, the clouds reduce the extent of sky polarization pattern that is useful for animal orientation much less than has hitherto been assumed. We further demonstrate quantitatively that the shorter the wavelength, the greater the proportion of celestial polarization that can be used by animals under cloudy-sky conditions. As has already been suggested by others, this phenomenon may solve the ultraviolet paradox of polarization vision in insects such as hymenopterans and dipterans. The present study extends previous findings by using the technique of 180 degrees imaging polarimetry to measure and analyse celestial polarization patterns. PMID:11551983

Pomozi, I; Horváth, G; Wehner, R

2001-09-01

74

High Quality Typhoon Cloud Image Restoration by Combining Genetic Algorithm with Contourlet Transform  

NASA Astrophysics Data System (ADS)

An efficient typhoon cloud image restoration algorithm is proposed. Having implemented contourlet transform to a typhoon cloud image, noise is reduced in the high sub-bands. Weight median value filter is used to reduce the noise in the contourlet domain. Inverse contourlet transform is done to obtain the de-noising image. In order to enhance the global contrast of the typhoon cloud image, in-complete Beta transform (IBT) is used to determine non-linear gray transform curve so as to enhance global contrast for the de-noising typhoon cloud image. Genetic algorithm is used to obtain the optimal gray transform curve. Information entropy is used as the fitness function of the genetic algorithm. Experimental results show that the new algorithm is able to well enhance the global for the typhoon cloud image while well reducing the noises in the typhoon cloud image.

Zhang, Changjiang; Wang, Xiaodong

2008-11-01

75

High Quality Typhoon Cloud Image Restoration by Combining Genetic Algorithm with Contourlet Transform  

SciTech Connect

An efficient typhoon cloud image restoration algorithm is proposed. Having implemented contourlet transform to a typhoon cloud image, noise is reduced in the high sub-bands. Weight median value filter is used to reduce the noise in the contourlet domain. Inverse contourlet transform is done to obtain the de-noising image. In order to enhance the global contrast of the typhoon cloud image, in-complete Beta transform (IBT) is used to determine non-linear gray transform curve so as to enhance global contrast for the de-noising typhoon cloud image. Genetic algorithm is used to obtain the optimal gray transform curve. Information entropy is used as the fitness function of the genetic algorithm. Experimental results show that the new algorithm is able to well enhance the global for the typhoon cloud image while well reducing the noises in the typhoon cloud image.

Zhang Changjiang; Wang Xiaodong [College of Mathematics, Physics and Information Engineering, Zhejiang Normal University, Jinhua (China)

2008-11-06

76

Radar imaging of ocean surface patterns  

NASA Technical Reports Server (NTRS)

The paper presents some examples of imaging radar oceanographic observations and discusses physical phenomena on the surface that may cause the radar image. The different ocean scattering theories are briefly discussed, including the tangent plane model, the Bragg-Rice model, and the Rayleigh scattering model. All but one of the images presented were obtained with an L-band HH-polarized radar; they include deep-ocean swells, coastal swells, wave refractions, internal waves, ship wakes, abrupt transitions in open-ocean surface roughness, surface slicks, island wind shadowing, and currents. Analyses are shown to suggest that the primary source of the L-band imagery of ocean surface patterns is the variation of small-scale surface roughness and local tilt angle. It is also noted that surface irregularities behave as isotropic scatterers for a radar wavelength of 25 cm.

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

1976-01-01

77

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

78

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

79

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

80

Image Transfer Through Cirrus Clouds. I. Ray Trace Analysis and Wave-Front Reconstruction  

Microsoft Academic Search

A new technique for modeling image transfer through cirrus clouds is presented. The technique uses a ray trace to model beam propagation through a three-dimensional volume of polydisperse, hexagonal ice crystals. Beyond the cloud, the technique makes use of standard Huygens Fresnel propagation methods. At the air cloud interface, each wave front is resolved into a ray distribution for input

Barbara T. Landesman; Peter J. Kindilien; Charles L. Matson; Thomas R. Caudill

2000-01-01

81

Advancements in identifying cirrus and multilayered cloud systems from operational satellite imagers at night  

NASA Astrophysics Data System (ADS)

Radiances and brightness temperatures from three near-infrared/infrared channels that are available on most current and past satellite imagers were used to develop automated algorithms for identifying multilayered cloud systems (cloud overlap) and cirrus clouds at night. The cloud overlap algorithm uses information from the 3.75 micron, 11 micron, and 12 micron regions of the spectrum and the cirrus algorithm uses 3.75 micron and 11 micron channel data. The cloud overlap algorithm was developed assuming that a scene with cloud overlap consists of a semitransparent ice cloud that overlaps a lower cloud composed of liquid water droplets. Cirrus clouds are taken to be high ice clouds with a visible optical depth of 5.0 or less. The algorithms are applied to single satellite pixels that are already assumed to be cloudy based on cloud mask information. The utility of each algorithm was demonstrated on two different Moderate Resolution Imaging Spectroradiometer (MODIS) scenes and the cloud overlap algorithm was validated against millimeter radar-derived cloud boundaries. Overall the results show that both algorithms have the potential to be very useful for nighttime cloud studies.

Pavolonis, Michael J.; Heidinger, Andrew K.

2005-01-01

82

Clouds  

NSDL National Science Digital Library

Clouds comprise a wonderful focus for classroom study. They're ubiquitous, ever-changing, scientifically interesting and, most importantly for teachers, they're cheap. The material presented here includes sections on cloud formation, cloud types, cloud pictures, other cloud-related phenomena, and a glossary.

Carl Wozniak

83

Closed Large Cell Clouds  

Atmospheric Science Data Center

...   View Larger Image The shape and size of cellular patterns within marine stratocumulus cloud layers can change ... When the cell centers are cloudy and the main sinking motion is concentrated at cell boundaries, the cells are referred to as ...

2013-04-19

84

Image transfer through cirrus clouds. I. Ray trace analysis and wave-front reconstruction.  

PubMed

A new technique for modeling image transfer through cirrus clouds is presented. The technique uses a ray trace to model beam propagation through a three-dimensional volume of polydisperse, hexagonal ice crystals. Beyond the cloud, the technique makes use of standard Huygens-Fresnel propagation methods. At the air-cloud interface, each wave front is resolved into a ray distribution for input to the ray trace software. Similarly, a wave front is reconstructed from the output ray distribution at the cloud-air interface. Simulation output from the ray trace program is presented and the modulation transfer function for stars imaged through cirrus clouds of varying depths is discussed. PMID:18354542

Landesman, B T; Kindilien, P J; Matson, C L; Caudill, T R

2000-10-20

85

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

86

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

87

A Routing Mechanism for Cloud Outsourcing of Medical Imaging Repositories.  

PubMed

Web-based technologies have been increasingly used in Picture Archive and Communication Systems (PACS), in services related to storage, distribution and visualization of medical images. Nowadays, many healthcare institutions are outsourcing their repositories to the Cloud. However, managing communications between multiple geo-distributed locations is still challenging due to the complexity of dealing with huge volumes of data and bandwidth requirements. Moreover, standard methodologies still do not take full advantage of outsourced archives, namely because their integration with other in-house solutions is troublesome. In order to improve the performance of distributed medical imaging networks, a smart routing mechanism was developed. This includes an innovative cache system based on splitting and dynamic management of DICOM objects. The proposed solution was successfully deployed in a regional PACS archive. The results obtained proved that it is better than conventional approaches, as it reduces remote access latency and also the required cache storage space. PMID:25343773

Marques Godinho, Tiago; Viana-Ferreira, Carlos; Bastiao Silva, Luis; Costa, Carlos

2014-10-16

88

A Study on Deep Images of Magellanic Clouds Survey  

NASA Astrophysics Data System (ADS)

The Visible and Infrared Survey Telescope for Astronomy (VISTA), which was launched by the European Southern Observatory, has provided data for several parts of survey region in Magellanic Clouds. The multi-epoch survey covers the same region in order to obtain deeper images which will show the information about the fainter objects. The catalogue is provided by VISTA Data Flow System (VDFS) which is designed for the general objects rather than the fainter sources. In order to solve this problem, the deep images from the mate data are made by using SWARP tool, and the photometry of the point spread function is performed on these deep images. Finally, the uncertainties and completeness of deep images are provided, and are compared with the data from VDFS. The result shows more fainter sources can be found by manual processing from their deep images. The final catalogue is 0.8 mag deeper than the VDFS for the sources with error less than 0.1 mag, and the number of sources is increased by 30% at 50% completeness limit.

Wang, S.

2014-01-01

89

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

90

Cloud elevations in near real time. [from geosynchronous satellite stereographic imaging  

NASA Technical Reports Server (NTRS)

The paper shows how cloud elevations can be obtained from geosynchronous satellites within 15 min of an event and to an accuracy of less than 250 m. After careful consideration of pertinent factors, it is decided that a dual satellite system in parallel geosynchronous orbits would be the most feasible configuration for stereographic imaging of cloud systems. The discussion covers tracking accuracy, choice of imaging systems, data transmission and processing, image correlation, and proposed cloud heighting system. The described partially man-interactive system is substantially within the present state of the art and could be the basis for an interim system for cloud height determination.

Shull, C. W.; Stephens, J. M.

1977-01-01

91

Aerosol patterns and aerosol-cloud-interactions off the West African Coast based on the A-train formation  

NASA Astrophysics Data System (ADS)

In this study, spatial and temporal aerosol patterns off the Western African coast are characterized and related to cloud properties, based on satellite data Atmospheric aerosols play a key role in atmospheric processes and influence our environmental system in a complex way. Their identification, characterization, transport patterns as well as their interactions with clouds pose major challenges. Especially the last aspect reveals major uncertainties in terms of the Earth's radiation budget as reported in the IPCC's Fourth Assessment Report (IPCC, 2007). Western and Southern Africa are dominated by two well-known source types of atmospheric aerosols. First, the Saharan Desert is the world's largest aeolian dust emitting source region. Second, biomass burning aerosol is commonly transported off-shore further south (Kaufman et al., 2005). Both aerosol types influence Earth's climate in different manners and can be detected by the MODIS (MODerate resolution Imaging Spectrometer) sensor onboard the EOS platforms as they propagate to the Central and Southern Atlantic. The motivation of this study was to reveal the seasonal pattern of the Saharan dust transport based on an observation period of 11 years and trying to explain the meteorological mechanisms. North African dust plumes are transported along a latitude of 19°N in July and 6°N in January. The seasonally fluctuating intensities adapt to the annual cycle of wind and precipitation regimes. A strong relationship is found between the spatial shift of the Azores High and the Saharan dust load over the middle Atlantic Ocean. Monthly Aerosol Optical Thickness products of Terra MODIS and NCEP-DOE (National Centers for Environmental Predictions) Reanalysis II data are used for this purpose. The relationship between aerosol and cloud droplet parameters is blurred by high sensitivities to aerosol size and composition (Feingold, 2003; McFiggans et al., 2006) as well as meteorological context (Ackerman et al., 2004). Satellite data from the A-train formation, including the Aqua, CloudSat and CALIPSO (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation) are used to analyze aerosol-cloud-interactions in detail, along with re-analysis data to constrain by meteorological conditions. Information about the vertical and geographical distribution of different aerosol types and cloud parameters will lead to a process-oriented understanding of these issues on a regional scale. Ackerman, A., Kirkpatrick, M., Stevens, D., & Toon, O. (2004). The impact of humidity above stratiform clouds on indirect aerosol climate forcing. Nature, 432(December), 1014-1017. doi:10.1038/nature03137.1. Feingold, G. (2003). First measurements of the Twomey indirect effect using ground-based remote sensors. Geophysical Research Letters, 30(6), 1287. doi:10.1029/2002GL016633 IPCC. (2007). Climate Change 2007: The Physical Science Basis. Contribution of Working group I to the Fourth Assessment Report of the Interfovernmental Panel on climate Change. Change [Solomon, S., D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M.Tignor and H.L. Miller (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. Kaufman, Y. J., Koren, I., Remer, L. A., Tanré, D., Ginoux, P., & Fan, S. (2005). Dust transport and deposition observed from the Terra-Moderate Resolution Imaging Spectroradiometer (MODIS) spacecraft over the Atlantic Ocean. Journal of Geophysical Research, 110(D10), 1-16. doi:10.1029/2003JD004436 McFiggans, G., Artaxo, P., Baltensperger, U., Coe, H., Facchini, M. C., Feingold, G., Fuzzi, S., et al. (2006). The effect of physical and chemical aerosol properties on warm cloud droplet activation. Atmospheric Chemistry and Physics, 6(9), 2593-2649. doi:10.5194/acp-6-2593-2006

Fuchs, Julia; Bendix, Jörg; Cermak, Jan

2013-04-01

92

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

93

Astronomy In The Cloud: Using Mapreduce For Image Coaddition  

NASA Astrophysics Data System (ADS)

In the coming decade, astronomical surveys of the sky will generate tens of terabytes of images and detect hundreds of millions of sources every night. The study of these sources will involve computational challenges such as anomaly detection, classification, and moving object tracking. Since such studies require the highest quality data, methods such as image coaddition, i.e., registration, stacking, and mosaicing, will be critical to scientific investigation. With a requirement that these images be analyzed on a nightly basis to identify moving sources, e.g., asteroids, or transient objects, e.g., supernovae, these datastreams present many computational challenges. Given the quantity of data involved, the computational load of these problems can only be addressed by distributing the workload over a large number of nodes. However, the high data throughput demanded by these applications may present scalability challenges for certain storage architectures. One scalable data-processing method that has emerged in recent years is MapReduce, and in this paper we focus on its popular open-source implementation called Hadoop. In the Hadoop framework, the data is partitioned among storage attached directly to worker nodes, and the processing workload is scheduled in parallel on the nodes that contain the required input data. A further motivation for using Hadoop is that it allows us to exploit cloud computing resources, i.e., platforms where Hadoop is offered as a service. We report on our experience implementing a scalable image-processing pipeline for the SDSS imaging database using Hadoop. This multi-terabyte imaging dataset provides a good testbed for algorithm development since its scope and structure approximate future surveys. First, we describe MapReduce and how we adapted image coaddition to the MapReduce framework. Then we describe a number of optimizations to our basic approach and report experimental results compring their performance. This work is funded by the NSF and by NASA.

Wiley, Keith; Connolly, A.; Gardner, J.; Krughoff, S.; Balazinska, M.; Howe, B.; Kwon, Y.; Bu, Y.

2011-01-01

94

Analysis of Point Cloud Generation from UAS Images  

NASA Astrophysics Data System (ADS)

Unmanned Aerial Systems (UAS) allow for the collection of low altitude aerial images, along with other geospatial information from a variety of companion sensors. The images can then be processed using sophisticated algorithms from the Computer Vision (CV) field, guided by the traditional and established procedures from photogrammetry. Based on highly overlapped images, new software packages which were specifically developed for UAS technology can easily create ground models, such as Point Clouds (PC), Digital Surface Model (DSM), orthoimages, etc. The goal of this study is to compare the performance of three different software packages, focusing on the accuracy of the 3D products they produce. Using a Nikon D800 camera installed on an ocotocopter UAS platform, images were collected during subsequent field tests conducted over the Olentangy River, north from the Ohio State University campus. Two areas around bike bridges on the Olentangy River Trail were selected because of the challenge the packages would have in creating accurate products; matching pixels over the river and dense canopy on the shore presents difficult scenarios to model. Ground Control Points (GCP) were gathered at each site to tie the models to a local coordinate system and help assess the absolute accuracy for each package. In addition, the models were also relatively compared to each other using their PCs.

Ostrowski, S.; Jó?ków, G.; Toth, C.; Vander Jagt, B.

2014-11-01

95

Automatic Image Analysis for Gene Expression Patterns of Fly Embryos  

E-print Network

1 Automatic Image Analysis for Gene Expression Patterns of Fly Embryos Hanchuan Peng 1§ , Fuhui Research Campus, Howard Hughes Medical Institute, Ashburn, VA 20147 2 Department of Computer Science on the analyses of these image patterns. The increasing availability of ISH image data motivates the development

Peng, Hanchuan

96

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

97

Determination of cloud and aerosol layers using CALIPSO and image processing  

NASA Astrophysics Data System (ADS)

The height of cloud and aerosol layers in the atmosphere is believed to affect climate change and air pollution because both of them have important direct effects on the radiation balance of the earth. In this paper, we study the ability of Cloud Aerosol LIDAR and Infrared Pathfinder Satellite Observation (CALIPSO) data to detect, locate and distinguish between cloud and aerosol layers in the atmosphere over Peninsula Malaysia. We also used image processing technique to differentiate between cloud and aerosol layers from the CALIPSO images. The cloud and aerosol layers mostly are seen at troposphere (>10 km) and lower stratosphere (>15km). The results shows that CALIPSO can be used to determine cloud and aerosol layers and image processing technique has successfully distinguished them in the atmosphere.

Alias, A. N.; MatJafri, M. Z.; Lim, H. S.; Abdullah, K.; Saleh, N. Mohd.

2008-10-01

98

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

99

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

100

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

101

Quantitative Comparison of Dense Cloud Detection of an Evolutionary Image Classification Algorithm to the MODIS Cloud Mask and to the VIIRS Cloud Mask  

NASA Astrophysics Data System (ADS)

The proper identification of cloud cover plays an important role for the accurate determination of atmospheric and surface parameters from remotely sensed data. The MODIS (Moderate Resolution Imaging Spectroradiometer) cloud mask algorithm has been used by NASA and other governmental agencies as input for models, analysis systems, and decision support tools. The Visible Infrared Imager Radiometer Suite (VIIRS) cloud mask will be an important product for the National Polar-orbiting Operational Environmental Satellite System (NPOESS) and it has been researched as a replacement alternative in many of the existing NASA programs. Among them, the Rapid Prototyping Capability (RPC) project, at the University of Mississippi, investigates the VIIRS data as a replacement for the MODIS data in the SERVIR Decision Support Tool, which uses cloud masks as required inputs. In this project, the performance of these algorithms is compared to the Evolutionary Image Classification Algorithm (EICA). This semi-automated learn-from- examples evolutionary framework was used for dense cloud detection by combining preprocessing functions with standard unsupervised classification algorithms. The preprocessing functions as well as the parameters used in the unsupervised classification step were defined by genetic programming as the evolutionary tool to search for the optimal solution. Genetic programming evolves (iterative trial and error process) preprocessing functions formed by spectral indices built from basic function blocks defined in the function set (arithmetic operations) and in the terminal set (spectral bands). MODIS granules covering Central America were selected at different dates during the fire season to be used as the study site. These granules were manually classified using the first two MODIS channels and were considered as reference data. The cloud mask generated from the evolutionary classification algorithm, the VIIRS cloud mask and the MODIS cloud mask results were then compared using the Kappa statistics as the measurement of success.

Momm, H. G.; Easson, G.

2006-12-01

102

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

103

3D Aerosol-Cloud Radiative Interaction Observed in Collocated MODIS and ASTER Images of Cumulus Cloud Fields  

NASA Technical Reports Server (NTRS)

3D aerosol-cloud interaction is examined by analyzing two images containing cumulus clouds in biomass burning regions in Brazil. The research consists of two parts. The first part focuses on identifying 3D clo ud impacts on the reflectance of pixel selected for the MODIS aerosol retrieval based purely on observations. The second part of the resea rch combines the observations with radiative transfer computations to identify key parameters in 3D aerosol-cloud interaction. We found that 3D cloud-induced enhancement depends on optical properties of nearb y clouds as well as wavelength. The enhancement is too large to be ig nored. Associated biased error in 1D aerosol optical thickness retrie val ranges from 50% to 140% depending on wavelength and optical prope rties of nearby clouds as well as aerosol optical thickness. We caution the community to be prudent when applying 1D approximations in comp uting solar radiation in dear regions adjacent to clouds or when usin g traditional retrieved aerosol optical thickness in aerosol indirect effect research.

Wen, Guoyong; Marshak, Alexander; Cahalan, Robert F.; Remer, Lorraine A.; Kleidman, Richard G.

2007-01-01

104

Testing of Shocked Interstellar Cloud Models Using Deep H? Images of the Cygnus Loop  

NASA Astrophysics Data System (ADS)

New H? images of selected regions of the Cygnus Loop supernova remnant taken at MDM Observatory are used to test 2D and 3D numerical shocked cloud simulation features including multiple leading shock fronts, cloud deformation, formation of R-T and K-H instabilities on the cloud front and sides, gas stripping, and shock reflection and diffraction around the rear of an ISM cloud. A relatively isolated cloud in the SNR's southwestern sector imaged at both low- and high-resolution provides an excellent look at a real cloud-shock interaction at an earlier stage than shown in Fesen, Downes, & Kwitter (1992, A.J., 104, 719). These new data: 1) indicate that the onset of K-H instabilities along the cloud face and sides may occur surprisingly soon (t_cc =~ 1) after shock front contact, 2) show that multiple shocks fronts form inside the cloud leading to a highly complex filamentary internal cloud structure, and 3) successfully detect the extremely faint reflected and diffracted shocks downstream around the rear of the cloud. Wide-field images taken with the KPNO Burrell Schmidt also show an unexpectedly far western displacement of nonradiative shock emission along the remnant's western limb, and extensive diffuse emission coincident with the line of nonradiative emission filaments east of NGC 6992/5.

Fesen, R. A.; Downes, R. A.

1992-12-01

105

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

106

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

107

Clouds  

NSDL National Science Digital Library

Students learn about the varieties of clouds, what they look like and how they can affect our lives. Introduction: Have you ever wondered what kind of cloud makes rain, or which one makes fog? Have you ever wondered if there are clouds that mean the weather if going to be good or not? Today, we're going to learn about three different clouds that may ...

Ms. Doxey

2010-03-26

108

H2 excitation imaging of the Orion Molecular Cloud  

NASA Astrophysics Data System (ADS)

Observations are reported of IR emission in H2, around 2 ?m in the K-band, obtained with the ESO 3.6 m telescope using the ADONIS adaptive optics system. Data cover a region of the Orion Molecular Cloud north of the Trapezium stars and SW of the Becklin-Neugebauer object. Excellent seeing yielded diffraction limited images in the v=2-1 S(1) line at 2.247 ?m. Excitation temperature images were created by combining these data with similar data for H2 emission in the v=1-0 S(1) line reported earlier (Vannier et al. \\cite{vannier}). Shock models are used to estimate densities in emitting clumps of material. In local zones with high excitation temperatures, post-shock densities are found to be as high as several times 108 cm-3, an order of magnitude denser than our previous estimates. We propose that the nature of these zones is dictated by the combined activity of shocks, which create dense structures, and the powerful radiation field of ?1C Ori which photoevaporates the boundaries of these structures. Mainly based on observations performed at the ESO/La Silla 3.6 m telescope. Reference is also made to observations performed at the CFHT 3.6 m telescope.

Kristensen, L. E.; Gustafsson, M.; Field, D.; Callejo, G.; Lemaire, J. L.; Vannier, L.; Pineau des Forêts, G.

2003-12-01

109

3D INDUSTRIAL RECONSTRUCTION BY FITTING CSG MODELS TO A COMBINATION OF IMAGES AND POINT CLOUDS  

Microsoft Academic Search

We present a method for 3D reconstruction of industrial sites using a combination of images and point clouds with a motivation of achieving higher levels of automation, precision, and reliability. Recent advances in 3D scanning technologies have made possible rapid and cost-effective acquisition of dense point clouds for 3D reconstruction. As the point clouds provide explicit 3D information, they have

Tahir Rabbani; Frank van den Heuvel

110

Geographical correlation of TV and IR images obtained from weather satellites. [cloud cover photography  

NASA Technical Reports Server (NTRS)

The requirements on the accuracy of geographical correlation of TV and IR cloud cover images are determined by the objective of the analysis of the weather information contained in these images. In the operational analysis case, the correlation accuracy need not be high. Errors of several tens of kilometers in determining the location of the cloud formation contours are considered acceptable in this case. Such correlation must be provided in real image reception time. Scientific studies require accurate correlation of the cloud formation contours. The errors in determining their position should be commensurate with the imaging system resolution. The geometric aspects of developing methods and equipment for geographical correlation of television and infrared images of cloud cover taken from Meteor satellites are discussed.

Ziman, Y. L.; Nepoklonov, B. N.; Rodionov, B. N.

1974-01-01

111

Longitudinal variability of Polar Mesospheric Cloud (PMC) albedo and frequency from the Cloud Imaging and Particle Size Experiment: Comparison of the 2007 and 2008 Northern Hemisphere cloud seasons  

NASA Astrophysics Data System (ADS)

The Cloud Imaging and Particle Size (CIPS) Experiment on the Aeronomy of Ice in the Mesosphere Mission (AIM) images Polar Mesospheric Clouds (PMCs) as a function of latitude and time. Data on PMC albedo and occurrence frequency have now been taken over two Northern Hemisphere seasons for 2007 and 2008 and one Southern season, 2007/2008. The data for the 2007 and 2007/2008 seasons have shown strong longitudinal variability of albedo and occurrence when averaged over periods of 15 to 20 days that are correlated to ice water content from the Solar Occultation for Ice Experiment (SOFIE) on AIM, and anti- correlated to temperature data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) and to the occurrence of gravity waves. We compare the time and longitudinal variations of cloud albedo and frequency of occurrence and temperature for the three seasons.

Merkel, A. W.; Rusch, D. W.; Thomas, G. E.; Palo, S.; Bailey, S. M.; Russell, J. M.; Hervig, M.; Chandran, A.

2008-12-01

112

Accuracy assessment of building point clouds automatically generated from iphone images  

NASA Astrophysics Data System (ADS)

Low-cost sensor generated 3D models can be useful for quick 3D urban model updating, yet the quality of the models is questionable. In this article, we evaluate the reliability of an automatic point cloud generation method using multi-view iPhone images or an iPhone video file as an input. We register such automatically generated point cloud on a TLS point cloud of the same object to discuss accuracy, advantages and limitations of the iPhone generated point clouds. For the chosen example showcase, we have classified 1.23% of the iPhone point cloud points as outliers, and calculated the mean of the point to point distances to the TLS point cloud as 0.11 m. Since a TLS point cloud might also include measurement errors and noise, we computed local noise values for the point clouds from both sources. Mean (?) and standard deviation (?) of roughness histograms are calculated as (?1 = 0.44 m., ?1 = 0.071 m.) and (?2 = 0.025 m., ?2 = 0.037 m.) for the iPhone and TLS point clouds respectively. Our experimental results indicate possible usage of the proposed automatic 3D model generation framework for 3D urban map updating, fusion and detail enhancing, quick and real-time change detection purposes. However, further insights should be obtained first on the circumstances that are needed to guarantee a successful point cloud generation from smartphone images.

Sirmacek, B.; Lindenbergh, R.

2014-06-01

113

Cloud frequency climatology at the Andes/Amazon transition: 1. Seasonal and diurnal cycles  

E-print Network

Cloud frequency climatology at the Andes/Amazon transition: 1. Seasonal and diurnal cycles Kate-scale cloud patterns. We examine the cloud climatology of a tropical Andean montane region in the context Satellite Cloud Climatology Project) DX cloud product (1983­2008), MODIS (Moderate Resolution Imaging

Malhi, Yadvinder

114

Weekly Cycle of Lightning and Associated Patterns of Rainfall, Cloud, and Aerosols over Korea and Adjacent Oceans during Boreal Summer  

NASA Technical Reports Server (NTRS)

In this study, we analyze the weekly cycle of lightning over Korea and adjacent oceans and associated variations of aerosols, clouds, precipitation, and atmospheric circulations, using aerosol optical depth (AOD) from the NASA Moderate resolution Imaging Spectroradiometer (MODIS) and Multi-angle Imaging SpectroRadiometer (MISR), cloud properties from MODIS, precipitation and storm height from Tropical Rainfall Measuring Mission (TRMM) satellite, and lightning data from the Korean Lightning Detection Network (KLDN) during 9-year from 2002 to 2010. Lightning data was divided into three approximately equal areas, land area of Korea, and two adjacent oceans, Yellow Sea and South Sea. Preliminary results show that the number of lightning increases during the middle of the week over Yellow Sea. AOD data also shows moderately significant midweek increase at about the same time as lightning peaks. These results are consistent with the recent studies showing the invigoration of storms with more ice hydrometeors by aerosols, and subsequently wash out of aerosols by rainfall. Frequency of lightning strokes tend to peak at weekend in land area and over South Sea, indicating local weekly anomalous circulation between land and adjacent ocean. On the other hand, lightning frequency over Yellow Sea appears to have very strong weekly cycle with midweek peak on around Wednesday. It is speculated that the midweek peak of lightning over Yellow Sea was related with aerosol transport from adjacent land area. AOD data also suggests midweek peak over Yellow Sea, however, the weekly cycle of AOD was not statistically significant. Changes in weekly cycle of lightning from pre-monsoon to monsoon season, as well as associated clouds and circulation patterns are also discussed.

Kim, Ji-In; Kim, Kyu-Myong

2011-01-01

115

Point cloud reconstruction with sub-pixel accuracy by slice-adaptive thresholding of X-ray computed tomography images  

Microsoft Academic Search

We present a methodology for the calculation of highly accurate point clouds from an image stack obtained with a two-dimensional industrial X-ray computed tomography scanner. The basic idea is to apply a different threshold value to each computed tomography image, which is then used for the calculation of the point cloud. A dense and smooth cloud can be obtained by

Andreas F. Obrist; Alexander Flisch; Juergen Hofmann

2004-01-01

116

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

E-print Network

PATTERNS OF SATELLITE-VIEWED, SUBTROPICAL, JET- STREAM CLOUDS IN RELATION TO THE OBSERVED WIND FIELD A Thesis by RICHARD JOEL VOGT Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirement... for the degree of MASTER OF SCIENCE December 1972 Major Subject: Meteorology PATTERNS OP SATELLITE-VIEWED, SUBTROPICAL, JET-STREAM CLOUDS IN RELATION TO THE OBSERVED WIND FIELD A Thesis by RICHARD JOEL VOGT Approved as to style and content by: (Chairman...

Vogt, Richard Joel

1972-01-01

117

Image analysis of complex patterns in nonlinear optical system  

NASA Astrophysics Data System (ADS)

In this paper, several methods of image analysis such as fast Fourier transform, power spectrum, and t phase angle, have been used to a pattern formation system to get the features of their own. Complex patterns such as hexagon, quasi-crystal, and superlattice patterns have been analyzed. The mechanisms of all stationary patterns are attributed to Turing instability. These patterns have a unique characteristic wave number that equals to Turing mode. It is found that these complex structures are composed of two simple component hexagonal pattern that are co-rotated by an angle. Both superlattice pattern and quasi-crystal pattern have been constructed as the angle is varied. Another type of superlattice pattern named as super-hexagonal pattern is resulted from interactions between Turing mode and its harmonics.

Liu, Fucheng; Ha, Yan; Wang, Xiaofei

2009-05-01

118

Temporally and spatially resolved imaging of laser-nucleated bubble cloud sonoluminescence.  

PubMed

Imaging techniques have been used to capture the temporal and spatial evolution of light emissions from collapsing bubble clouds at high static pressures. Emission events lasting up to 70 ns with peak diameters nearing 1 mm have been observed. Observations of the cloud evolution before and after emission events have been made. Photomultiplier tube monitoring has been employed in conjunction with imaging to study the temporal characteristics of light emission. PMID:23004893

Sukovich, Jonathan R; Sampathkumar, Ashwin; Anderson, Phillip A; Holt, R Glynn; Pishchalnikov, Yuri A; Gaitan, D Felipe

2012-05-01

119

Temporally and spatially resolved imaging of laser-nucleated bubble cloud sonoluminescence  

NASA Astrophysics Data System (ADS)

Imaging techniques have been used to capture the temporal and spatial evolution of light emissions from collapsing bubble clouds at high static pressures. Emission events lasting up to 70 ns with peak diameters nearing 1 mm have been observed. Observations of the cloud evolution before and after emission events have been made. Photomultiplier tube monitoring has been employed in conjunction with imaging to study the temporal characteristics of light emission.

Sukovich, Jonathan R.; Sampathkumar, Ashwin; Anderson, Phillip A.; Holt, R. Glynn; Pishchalnikov, Yuri A.; Gaitan, D. Felipe

2012-05-01

120

A novel approach for the extraction of cloud motion vectors using airglow imager measurements  

NASA Astrophysics Data System (ADS)

The paper explores the possibility of implementing an advanced photogrammetric technique, generally employed for satellite measurements, on airglow imager, a ground-based remote sensing instrument primarily used for upper atmospheric studies, measurements of clouds for the extraction of cloud motion vectors (CMVs). The major steps involved in the algorithm remain the same, including image processing for better visualization of target elements and noise removal, identification of target cloud, setting a proper search window for target cloud tracking, estimation of cloud height, and employing 2-D cross-correlation to estimate the CMVs. Nevertheless, the implementation strategy at each step differs from that of satellite, mainly to suit airglow imager measurements. For instance, climatology of horizontal winds at the measured site has been used to fix the search window for target cloud tracking. The cloud height is estimated very accurately, as required by the algorithm, using simultaneous collocated Lidar measurements. High-resolution, both in space and time (4 min), cloud imageries are employed to minimize the errors in retrieved CMVs. The derived winds are evaluated against MST radar-derived winds by considering it as a reference. A very good correspondence is seen between these two wind measurements, both showing similar wind variation. The agreement is also found to be good in the both zonal and meridional wind velocities with RMSEs < 2.4 m s-1. At the end, the strengths and limitations of the algorithm are discussed, with possible solutions, wherever required.

Satheesh Kumar, S.; Narayana Rao, T.; Taori, A.

2015-03-01

121

Satellite retrieval of convective cloud base temperature based on the NPP/VIIRS Imager  

NASA Astrophysics Data System (ADS)

The advent of the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar-Orbiting Partnership (NPP) satellite provided a quantum jump in the satellite capabilities of retrieving cloud properties, because it nearly tripled the resolution in the thermal channels (375 m). This allowed us to develop a methodology for retrieving convective cloud base temperature (Tb) and validate it over the Atmospheric System Research Southern Great Plains site for the satellite early afternoon overpass time. The standard error of the Tb retrieval was only 1.1°C. The knowledge of Tb allows the calculation of cloud base height and the depth of the boundary layer, as well as the boundary layer water vapor mixing ratio with an accuracy of about 10%. The feasibility of retrieving cloud base temperature and height is an essential component that is required for retrieving cloud condensation nuclei (CCN) from satellites by using convective clouds as natural CCN chambers.

Zhu, Yannian; Rosenfeld, Daniel; Yu, Xing; Liu, Guihua; Dai, Jin; Xu, Xiaohong

2014-02-01

122

The identification of cloud types in LANDSAT MSS images. [Great Britain  

NASA Technical Reports Server (NTRS)

The author has identified the following significant results. Five general families of clouds were identified: cumulonimbiform, cumuliform, stratiform, stratocumuliform, and cirriform. Four members of this five-fold primary division of clouds were further divided into a number of subgroups. The MSS observed and recorded earth radiation in four different wavebands. Two of these bands (4 and 5) image in the visible portion of the electromagnetic spectrum, while the others (6 and 7) image the short wave portion, or just into the infrared. The main differences between the appearances of clouds in the four wavebands are related to the background brightness of land and sea surfaces.

Barrett, E. C. (principal investigator); Grant, C. K.

1976-01-01

123

Pattern Recognition Software and Techniques for Biological Image Analysis  

PubMed Central

The increasing prevalence of automated image acquisition systems is enabling new types of microscopy experiments that generate large image datasets. However, there is a perceived lack of robust image analysis systems required to process these diverse datasets. Most automated image analysis systems are tailored for specific types of microscopy, contrast methods, probes, and even cell types. This imposes significant constraints on experimental design, limiting their application to the narrow set of imaging methods for which they were designed. One of the approaches to address these limitations is pattern recognition, which was originally developed for remote sensing, and is increasingly being applied to the biology domain. This approach relies on training a computer to recognize patterns in images rather than developing algorithms or tuning parameters for specific image processing tasks. The generality of this approach promises to enable data mining in extensive image repositories, and provide objective and quantitative imaging assays for routine use. Here, we provide a brief overview of the technologies behind pattern recognition and its use in computer vision for biological and biomedical imaging. We list available software tools that can be used by biologists and suggest practical experimental considerations to make the best use of pattern recognition techniques for imaging assays. PMID:21124870

Shamir, Lior; Delaney, John D.; Orlov, Nikita; Eckley, D. Mark; Goldberg, Ilya G.

2010-01-01

124

Retrieval of Ice Cloud Parameters Using a Microwave Imaging Radiometer  

Microsoft Academic Search

Based on the radiative transfer theory, the microwave radiance emanating from ice clouds at arbitrary viewing angles is expressed as an analytic function of the cloud ice water path (IWP), the particle effective diameter (De), and the particle bulk density (i). Thus, for a given particle density, the earth-viewing measurements at two frequencies (e.g., 340 and 89 GHz) can provide

Fuzhong Weng; Norman C. Grody

2000-01-01

125

Estimation of cloud optical thickness by processing SEVIRI images and implementing a semi analytical cloud property retrieval algorithm  

NASA Astrophysics Data System (ADS)

Clouds play a very important role in the Earth's climate system, as they form an intermediate layer between Sun and the Earth. Satellite remote sensing systems are the only means to provide information about clouds on large scales. The geostationary satellite, Meteosat Second Generation (MSG) has onboard an imaging radiometer, the Spinning Enhanced Visible and Infrared Imager (SEVIRI). SEVIRI is a 12 channel imager, with 11 channels observing the earth's full disk with a temporal resolution of 15 min and spatial resolution of 3 km at nadir, and a high resolution visible (HRV) channel. The visible channels (0.6 µm and 0.81 µm) and near infrared channel (1.6µm) of SEVIRI are being used to retrieve the cloud optical thickness (COT). The study domain is over Europe covering the region between 35°N - 70°N and 10°W - 30°E. SEVIRI level 1.5 images over this domain are being acquired from the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) archive. The processing of this imagery, involves a number of steps before estimating the COT. The steps involved in pre-processing are as follows. First, the digital count number is acquired from the imagery. Image geo-coding is performed in order to relate the pixel positions to the corresponding longitude and latitude. Solar zenith angle is determined as a function of latitude and time. The radiometric conversion is done using the values of offsets and slopes of each band. The values of radiance obtained are then used to calculate the reflectance for channels in the visible spectrum using the information of solar zenith angle. An attempt is made to estimate the COT from the observed radiances. A semi analytical algorithm [Kokhanovsky et al., 2003] is implemented for the estimation of cloud optical thickness from the visible spectrum of light intensity reflected from clouds. The asymptotical solution of the radiative transfer equation, for clouds with large optical thickness, is the basis of this algorithm. The two visible channels of SEVIRI are used to find the COT and the near infra red channel to estimate the effective radius of droplets. Estimation of COT using a semi analytical scheme, which doesn't involve the conventional look-up table approach, is the aim of this work and henceforth, vertically integrated liquid water (w) or ice water content will be retrieved. The COT estimated and w obtained, will be compared with the values obtained from other approaches and will be validated with in situ measurements. Corresponding author address: Praveen Pandey, VITO - Flemish Institute for Technological Research, Boeretang 200, B 2400, Mol, Belgium. E-mail: praveen.pandey@vito.be

Pandey, P.; De Ridder, K.; van Lipzig, N.

2009-04-01

126

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

127

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

128

Genetic refinement of cloud-masking algorithms for the multi-spectral thermal imager (MTI)  

SciTech Connect

The Multi-spectral Thermal Imager (MTI) is a high-performance remote-sensing satellite designed, owned and operated by the U.S. Department of Energy, with a dual mission in environmental studies and in nonproliferation. It has enhanced spatial and radiometric resolutions and state-of-the-art calibration capabilities. This instrumental development puts a new burden on retrieval algorithm developers to pass this accuracy on to the inferred geophysical parameters. In particular, the atmospheric correction scheme assumes the intervening atmosphere will be modeled as a plane-parallel horizontally-homogeneous medium. A single dense-enough cloud in view of the ground target can easily offset reality from the calculations, hence the need for a reliable cloud-masking algorithm. Pixel-scale cloud detection relies on the simple facts that clouds are generally whiter, brighter, and colder than the ground below; spatially, dense clouds are generally large on some scale. This is a good basis for searching multispectral datacubes for cloud signatures. However, the resulting cloud mask can be very sensitive to the choice of thresholds in whiteness, brightness, temperature, and connectivity. We have used a genetic algorithm trained on (MODIS Airborne Simulator-based) simulated MTI data to design a cloud-mask. Its performance is compared quantitatively to hand-drawn training data and to the EOS/Terra MODIS cloud mask.

Hirsch, K. L. (Karen L.); Davis, A. B. (Anthony B.); Harvey, N. R. (Neal R.); Rohde, C. A. (Charles A.); Brumby, Steven P.

2001-01-01

129

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

130

Optical Imaging of Flow Pattern and Phantom  

NASA Technical Reports Server (NTRS)

Time-resolved optical imaging technique has been used to image the spatial distribution of small droplets and jet sprays in a highly scattering environment. The snake and ballistic components of the transmitted pulse are less scattered, and contain direct information about the sample to facilitate image formation as opposed to the diffusive components which are due to multiple collisions as a light pulse propagates through a scattering medium. In a time-gated imaging scheme, these early-arriving, image-bearing components of the incident pulse are selected by opening a gate for an ultrashort period of time and a shadowgram image is detected. Using a single shot cooled CCD camera system, the formation of water droplets is monitored as a function of time. Picosecond time-gated image of drop in scattering cells, spray droplets as a function of let speed and gas pressure, and model calcification samples consisted of calcium carbonate particles of irregular shapes ranging in size from 0. 1 to 1.5 mm affixed to a microscope slide have been measured. Formation produced by an impinging jet will be further monitored using a CCD with 1 kHz framing illuminated with pulsed light. The desired image resolution of the fuel droplets is on the 20 pm scale using early light through a highly scattering medium. A 10(exp -6)m displacement from a jet spray with a flow speed of 100 m/sec introduced by the ns grating pulse used in the imaging is negligible. Early ballistic/snake light imaging offers nondestructive and noninvasive method to observe the spatial distribution of hidden objects inside a highly scattering environment for space, biomedical, and materials applications. In this paper, the techniques we will present are time-resolved K-F transillumination imaging and time-gated scattered light imaging. With a large dynamic range and high resolution, time-gated early light imaging has the potential for improving rocket/aircraft design by determining jets shape and particle sizes. Refinements to these techniques may enable drop size measurements in the highly scattering, optically dense region of multi-element rocket injectors. These types of measurements should greatly enhance the design of stable, and higher performing rocket engines.

Galland, Pierre A.; Liang, X.; Wang, L.; Ho, P. P.; Alfano, R. R.; Breisacher, K.

1999-01-01

131

Methodology to detect patterns in fluid-flow images  

Microsoft Academic Search

We are interested in the development of an efficient computational visual system to study dynamic fluids and in this paper we present a methodology to detect patterns in flow-like images. These patterns are called in the Dynamical Systems theory critical points or single points. This method, like other previous methodologies presented in related literature, involves four steps: estimation of flow

Paulo S. Rodrigues; Arnaldo de Araujo Albuquerque; Marcos P. Barbosa

1999-01-01

132

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

133

New Images from Hubble and Galileo: Hubble Finds Many Bright Clouds on Uranus  

NSDL National Science Digital Library

NASA has recently released a number of new images from the Hubble Space Telescope and the Galileo Project. Hubble has discovered about twenty orange-colored clouds near the prominent bright band of Uranus which circle the planet at more than 300 mph. The site offers a press release and images in several formats.

1998-01-01

134

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

135

Synoptic imaging of nearshore bathymetric patterns  

NASA Astrophysics Data System (ADS)

A new technique for near real-time optical imaging of surf zone morphology, synoptic imaging, implemented at Scripps Beach, La Jolla, California, permits simultaneous measurements of the time-varying position of individual linear and lunate megaripples, fields of bed forms, rocks, cobble patches, beach steps and sandbars, and troughs. A varying threshold filter for brightness is applied to video frames sampled at 1 Hz to remove pixels corresponding to surface foam and suspended bubbles or sediment. Remaining fragments of the video frames are averaged over time intervals generally ranging from 5 to 10 min to produce images of the surf zone sand bed. To facilitate accurate measurement of the position of sand bed features, these images are enhanced to increase feature visibility, transformed to plan view, and corrected for refraction using surveyed bathymetry and tide level. Contrast in the images results from differences in water depth, shading variations from tilted bed surfaces, and changes in bed material. The surveyed positions of megaripples and sandbars correspond to the positions of persistent features in the images. A ray path model quantifying sand bed contrast as a function of water depth, angle of line-of-sight, and light attenuation coefficient in water predicts that for the Scripps Beach field site, bed forms with height as small as 0.03-0.2 m can be detected in water depths up to 2.5 m, in accord with observations, and that visibility can be improved by changing the line of sight toward overhead viewing. Bed visibility is reduced by persistent surface foam and water turbidity generated by waves with period <8 s and height exceeding 1.5 m. Example images showing transitions between linear and lunate megaripples, location of megaripple crestlines, and the interaction between sandbars, bed form fields, and cobble patches illustrate the potential of synoptic imaging.

Clarke, L. B.; Werner, B. T.

2003-01-01

136

Watershed identification of polygonal patterns in noisy SAR images  

Microsoft Academic Search

This paper describes a new approach to pattern recognition in Synthetic Aperture Radar (SAR) images. A visual analysis of the images provided by NASA's Magellan mission to Venus has revealed a number of zones showing polygonal-shaped faults on the surface of the planet. The goal of this paper is to provide a method to automate the identification of such zones.

Pierre Moreels; Suzanne E. Smrekar

2003-01-01

137

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

138

Investigation into Cloud Computing for More Robust Automated Bulk Image Geoprocessing  

NASA Technical Reports Server (NTRS)

Geospatial resource assessments frequently require timely geospatial data processing that involves large multivariate remote sensing data sets. In particular, for disasters, response requires rapid access to large data volumes, substantial storage space and high performance processing capability. The processing and distribution of this data into usable information products requires a processing pipeline that can efficiently manage the required storage, computing utilities, and data handling requirements. In recent years, with the availability of cloud computing technology, cloud processing platforms have made available a powerful new computing infrastructure resource that can meet this need. To assess the utility of this resource, this project investigates cloud computing platforms for bulk, automated geoprocessing capabilities with respect to data handling and application development requirements. This presentation is of work being conducted by Applied Sciences Program Office at NASA-Stennis Space Center. A prototypical set of image manipulation and transformation processes that incorporate sample Unmanned Airborne System data were developed to create value-added products and tested for implementation on the "cloud". This project outlines the steps involved in creating and testing of open source software developed process code on a local prototype platform, and then transitioning this code with associated environment requirements into an analogous, but memory and processor enhanced cloud platform. A data processing cloud was used to store both standard digital camera panchromatic and multi-band image data, which were subsequently subjected to standard image processing functions such as NDVI (Normalized Difference Vegetation Index), NDMI (Normalized Difference Moisture Index), band stacking, reprojection, and other similar type data processes. Cloud infrastructure service providers were evaluated by taking these locally tested processing functions, and then applying them to a given cloud-enabled infrastructure to assesses and compare environment setup options and enabled technologies. This project reviews findings that were observed when cloud platforms were evaluated for bulk geoprocessing capabilities based on data handling and application development requirements.

Brown, Richard B.; Smoot, James C.; Underwood, Lauren; Armstrong, C. Duane

2012-01-01

139

Pushing the limits of imaging using patterned illumination  

NASA Astrophysics Data System (ADS)

The image captured by an imaging system is subject to constraints imposed by the wave nature of light and the geometry of image formation. The former limits the resolving power of the imager while the latter results in a loss of size and range information. The body of work presented in this dissertation strives to overcome the aforementioned limits. The suite of techniques and apparatus ideas disclosed in the work afford imagers the unique ability to capture spatial detail lost to optical blur, while also recovering range information. A recurring theme in the work is the notion of imaging under patterned illumination. The Moire fringes arising from the heterodyning of the object detail and the patterned illumination, are used to improve the resolving power of the imager. The deformations in the phase of the detected illumination pattern, aid in the recovery of range information. The work furnishes a comprehensive mathematical model for imaging under patterned illumination that accommodates blur due to the imaging/illumination optics, and the perspective foreshortening observed at macroscopic scales. The model discloses the existence of a family of active stereo arrangements that jointly support super resolution (improvement of resolving power) and scene recovery (recovery of range information). The work also presents a new description of the theoretical basis for super resolution. The description confirms that an improvement in resolving power results from the computational engineering of the imager impulse response. The above notion is explored further, in developing a strategy for engineering the impulse response of an imager, using patterned illumination. It is also established that optical aberrations are not an impediment to super resolution. Furthermore, the work advances the state-of-the-art in scene recovery by establishing that a broader class of sinusoidal patterns may be used to recover range information, while circumventing the extensive calibration process employed by current approaches. The work concludes by examining an extreme example of super resolution using patterned illumination. In particular, a strategy that overcomes the severe anisotropy in the resolving power of a single-lens imager is examined. Spatial frequency analysis of the reconstructed image confirms the effectiveness of lattice illumination in engineering a computational imager with near isotropic resolving power.

Rangarajan, Prasanna

140

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

SciTech Connect

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, A. B. (Anthony B.); Rohde, C. A. (Charles A.); Ho, Cheng,

2001-01-01

141

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 Infrastructure-as-a-Service (IaaS) cloud computing is gain- ing significant interest in industry and academia as an al- ternative platform for running scientific applications. Given the dynamic nature of IaaS clouds

Paris-Sud XI, Université de

142

Diurnal, Seasonal, and Interannual Variations of Cloud Properties Derived for CERES From Imager Data  

NASA Technical Reports Server (NTRS)

Simultaneous measurement of the radiation and cloud fields on a global basis is a key component in the effort to understand and model the interaction between clouds and radiation at the top of the atmosphere, at the surface, and within the atmosphere. The NASA Clouds and Earth s Radiant Energy System (CERES) Project, begun in 1998, is meeting this need. Broadband shortwave (SW) and longwave radiance measurements taken by the CERES scanners at resolutions between 10 and 20 km on the Tropical Rainfall Measuring Mission (TRMM), Terra, and Aqua satellites are matched to simultaneous retrievals of cloud height, phase, particle size, water path, and optical depth OD from the TRMM Visible Infrared Scanner (VIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS) on Terra and Aqua. Besides aiding the interpretation of the broadband radiances, the CERES cloud properties are valuable for understanding cloud variations at a variety of scales. In this paper, the resulting CERES cloud data taken to date are averaged at several temporal scales to examine the temporal and spatial variability of the cloud properties on a global scale at a 1 resolution.

Minnis, Patrick; Young, David F.; Sun-Mack, Sunny; Trepte, Qing Z.; Chen, Yan; Brown, Richard R.; Gibson, Sharon; Heck, Patrick W.

2004-01-01

143

Optical images of MCLD123.5+24.9: a cloud illuminated by the North star?  

Microsoft Academic Search

We present B R I images of a 1degr {x}1degr field centered on the molecular cloud (MCLD123.5+24.9) located in the large infrared cirrus known as the Polaris Flare. The optical images are compared with IRAS images and an extinction map derived from stellar reddenings. We analyse the possibility for the North star (HD8890), only 1degr North of the field, to

F. Zagury; F. Boulanger; V. Banchet

1999-01-01

144

Orientation of Airborne Laser Scanning Point Clouds with Multi-View, Multi-Scale Image Blocks  

PubMed Central

Comprehensive 3D modeling of our environment requires integration of terrestrial and airborne data, which is collected, preferably, using laser scanning and photogrammetric methods. However, integration of these multi-source data requires accurate relative orientations. In this article, two methods for solving relative orientation problems are presented. The first method includes registration by minimizing the distances between of an airborne laser point cloud and a 3D model. The 3D model was derived from photogrammetric measurements and terrestrial laser scanning points. The first method was used as a reference and for validation. Having completed registration in the object space, the relative orientation between images and laser point cloud is known. The second method utilizes an interactive orientation method between a multi-scale image block and a laser point cloud. The multi-scale image block includes both aerial and terrestrial images. Experiments with the multi-scale image block revealed that the accuracy of a relative orientation increased when more images were included in the block. The orientations of the first and second methods were compared. The comparison showed that correct rotations were the most difficult to detect accurately by using the interactive method. Because the interactive method forces laser scanning data to fit with the images, inaccurate rotations cause corresponding shifts to image positions. However, in a test case, in which the orientation differences included only shifts, the interactive method could solve the relative orientation of an aerial image and airborne laser scanning data repeatedly within a couple of centimeters. PMID:22454569

Rönnholm, Petri; Hyyppä, Hannu; Hyyppä, Juha; Haggrén, Henrik

2009-01-01

145

D Point Cloud Model Colorization by Dense Registration of Digital Images  

NASA Astrophysics Data System (ADS)

Architectural heritage is a historic and artistic property which has to be protected, preserved, restored and must be shown to the public. Modern tools like 3D laser scanners are more and more used in heritage documentation. Most of the time, the 3D laser scanner is completed by a digital camera which is used to enrich the accurate geometric informations with the scanned objects colors. However, the photometric quality of the acquired point clouds is generally rather low because of several problems presented below. We propose an accurate method for registering digital images acquired from any viewpoints on point clouds which is a crucial step for a good colorization by colors projection. We express this image-to-geometry registration as a pose estimation problem. The camera pose is computed using the entire images intensities under a photometric visual and virtual servoing (VVS) framework. The camera extrinsic and intrinsic parameters are automatically estimated. Because we estimates the intrinsic parameters we do not need any informations about the camera which took the used digital image. Finally, when the point cloud model and the digital image are correctly registered, we project the 3D model in the digital image frame and assign new colors to the visible points. The performance of the approach is proven in simulation and real experiments on indoor and outdoor datasets of the cathedral of Amiens, which highlight the success of our method, leading to point clouds with better photometric quality and resolution.

Crombez, N.; Caron, G.; Mouaddib, E.

2015-02-01

146

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

147

Multiscale vector fields for image pattern recognition  

NASA Technical Reports Server (NTRS)

A uniform processing framework for low-level vision computing in which a bank of spatial filters maps the image intensity structure at each pixel into an abstract feature space is proposed. Some properties of the filters and the feature space are described. Local orientation is measured by a vector sum in the feature space as follows: each filter's preferred orientation along with the strength of the filter's output determine the orientation and the length of a vector in the feature space; the vectors for all filters are summed to yield a resultant vector for a particular pixel and scale. The orientation of the resultant vector indicates the local orientation, and the magnitude of the vector indicates the strength of the local orientation preference. Limitations of the vector sum method are discussed. Investigations show that the processing framework provides a useful, redundant representation of image structure across orientation and scale.

Low, Kah-Chan; Coggins, James M.

1990-01-01

148

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

149

Phase contrast image restoration via dictionary representation of diffraction patterns.  

PubMed

The restoration of microscopy images makes the segmentation and detection of cells easier and more reliable, which facilitates automated cell tracking and cell behavior analysis. In this paper, the authors analyze the image formation process of phase contrast images and propose an image restoration method based on the dictionary representation of diffraction patterns. By formulating and solving a min-l1 optimization problem, each pixel is restored into a feature vector corresponding to the dictionary representation. Cells in the images are then segmented by the feature vector clustering. In addition to segmentation, since the feature vectors capture the information on the phase retardation caused by cells, they can be used for cell stage classification between intermitotic and mitotic/apoptotic stages. Experiments on three image sequences demonstrate that the dictionary-based restoration method can restore phase contrast images containing cells with different optical natures and provide promising results on cell stage classification. PMID:23286182

Su, Hang; Yin, Zhaozheng; Kanade, Takeo; Huh, Seungil

2012-01-01

150

Improvements in Near-Terminator and Nocturnal Cloud Masks using Satellite Image Data over the Atmospheric Radiation Measurement Sites  

NASA Technical Reports Server (NTRS)

Cloud detection using satellite measurements presents a big challenge near the terminator where the visible (VIS; 0.65 (micro)m) channel becomes less reliable and the reflected solar component of the solar infrared 3.9-(micro)m channel reaches very low signal-to-noise ratio levels. As a result, clouds are underestimated near the terminator and at night over land and ocean in previous Atmospheric Radiation Measurement (ARM) Program cloud retrievals using Geostationary Operational Environmental Satellite (GOES) imager data. Cloud detection near the terminator has always been a challenge. For example, comparisons between the CLAVR-x (Clouds from Advanced Very High Resolution Radiometer (AVHRR)) cloud coverage and Geoscience Laser Altimeter System (GLAS) measurements north of 60 degrees N indicate significant amounts of missing clouds from AVHRR because this part of the world was near the day/night terminator viewed by AVHRR. Comparisons between MODIS cloud products and GLAS at the same regions also shows the same difficulty in the MODIS cloud retrieval (Pavolonis and Heidinger 2005). Consistent detection of clouds at all times of day is needed to provide reliable cloud and radiation products for ARM and other research efforts involving the modeling of clouds and their interaction with the radiation budget. To minimize inconsistencies between daytime and nighttime retrievals, this paper develops an improved twilight and nighttime cloud mask using GOES-9, 10, and 12 imager data over the ARM sites and the continental United States (CONUS).

Trepte, Q. Z.; Minnis, P.; Heck, R. W.; Palikonda, R.

2005-01-01

151

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

E-print Network

AN INVESTIGATION OF TIME VARIATIONS IN A SUBTROPICAL JET STREAM AND THE ASSOCIATED CLOUD PATTERNS AS SHOWN BY TIROS I A Thesis By PETER FRANCIS LESTER Submitted to the Graduate College of the Texas A6M University in partial fulfillment... of the requirements for the degree of MASTER OF SCIENCE August 1964 Ma( or Sub] ect: METEOROLOGY AN INVESTIGATION OF TIME VARIATIONS IN A SUBTROPICAL JET STREAM AND THE ASSOCIATED CLOUD PATTERNS AS SHOWN BY TIROS I A Thesis By PETER FRANCIS LESTER Approved...

Lester, Peter Francis

1964-01-01

152

The application of cloud computing to the creation of image mosaics and management of their provenance  

NASA Astrophysics Data System (ADS)

We have used the Montage image mosaic engine to investigate the cost and performance of processing images on the Amazon EC2 cloud, and to inform the requirements that higher-level products impose on provenance management technologies. We will present a detailed comparison of the performance of Montage on the cloud and on the Abe high performance cluster at the National Center for Supercomputing Applications (NCSA). Because Montage generates many intermediate products, we have used it to understand the science requirements that higher-level products impose on provenance management technologies. We describe experiments with provenance management technologies such as the "Provenance Aware Service Oriented Architecture" (PASOA).

Berriman, G. Bruce; Deelman, Ewa; Groth, Paul; Juve, Gideon

2010-07-01

153

Detection and tracking of gas clouds in an urban area by imaging infrared spectroscopy  

NASA Astrophysics Data System (ADS)

The release of toxic industrial compounds in urban areas is a threat for the population and the environment. In order to supply emergency response forces with information about the released compounds after accidents or terrorist attacks, monitoring systems such as the scanning imaging spectrometer SIGIS 2 or the hyperspectral imager HI 90 were developed. Both systems are based on the method of infrared spectroscopy. The systems were deployed to monitor gas clouds released in the harbor area of Hamburg. The gas clouds were identified, visualized and quantified from a distance in real time. Using data of two systems it was possible to identify contaminated areas and to determine the source location.

Sabbah, Samer; Rusch, Peter; Gerhard, Jörn-Hinnrich; Harig, Roland

2013-05-01

154

High Speed Imaging of Bubble Clouds Generated in Pulsed Ultrasound Cavitational Therapy—Histotripsy  

PubMed Central

Our recent studies have demonstrated that mechanical fractionation of tissue structure with sharply demarcated boundaries can be achieved using short (<20 ?s), high intensity ultrasound pulses delivered at low duty cycles. We have called this technique histotripsy. Histotripsy has potential clinical applications where noninvasive tissue fractionation and/or tissue removal are desired. The primary mechanism of histotripsy is thought to be acoustic cavitation, which is supported by a temporally changing acoustic backscatter observed during the histotripsy process. In this paper, a fast-gated digital camera was used to image the hypothesized cavitating bubble cloud generated by histotripsy pulses. The bubble cloud was produced at a tissue-water interface and inside an optically transparent gelatin phantom which mimics bulk tissue. The imaging shows the following: 1) Initiation of a temporally changing acoustic backscatter was due to the formation of a bubble cloud; 2) The pressure threshold to generate a bubble cloud was lower at a tissue-fluid interface than inside bulk tissue; and 3) at higher pulse pressure, the bubble cloud lasted longer and grew larger. The results add further support to the hypothesis that the histotripsy process is due to a cavitating bubble cloud and may provide insight into the sharp boundaries of histotripsy lesions. PMID:18019247

Xu, Zhen; Raghavan, Mekhala; Hall, Timothy L.; Chang, Ching-Wei; Mycek, Mary-Ann; Fowlkes, J. Brian; Cain, Charles A.

2009-01-01

155

Active probing of cloud thickness and optical depth 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{sup o} 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. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Section 2 covers the up-to-date evolution of the nighttime WAIL instrument at LANL. Section 3 reports our progress towards daytime capability for WAIL, an important extension to full diurnal cycle monitoring by means of an ultra-narrow magneto-optic atomic line filter. Section 4 describes briefly how the important cloud properties can be inferred from WAIL signals.

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

2002-01-01

156

Measurement and Imaging of Gases in Industrial Environments with the Infrared Gas Cloud Scanner  

Microsoft Academic Search

Usual gas sampling methods for checking compliance with threshold limit values do not provide information on the cause of the observed exposure, nor is gas dispersion being visualized on-line. For effective improvement of noncompliance work situations, such information on causes and gas dispersion patterns is indispensable. The infrared gas cloud (IGC) scanner was developed for fast, remote, and quantitative identification

Willem M. ter Kuile; Bas Knoll; Paul G. M. Hesselink

1993-01-01

157

Automatic image analysis for gene expression patterns of fly embryos  

Microsoft Academic Search

BACKGROUND: Staining the mRNA of a gene via in situ hybridization (ISH) during the development of a D. melanogaster embryo delivers the detailed spatio-temporal pattern of expression of the gene. Many biological problems such as the detection of co-expressed genes, co-regulated genes, and transcription factor binding motifs rely heavily on the analyses of these image patterns. The increasing availability of

Hanchuan Peng; Fuhui Long; Jie Zhou; Garmay Leung; Michael B Eisen; Eugene W Myers

2007-01-01

158

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

159

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

160

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

161

A medical image archive solution in the cloud  

Microsoft Academic Search

Growing long-term cost of managing an onsite medical imaging archive has been a subject which the health care industry struggles with. Based on the current trend, it is estimated that over 1 billion diagnostic imaging procedures will be performed in the United States during year 2014, generating about 100 Petabytes of data. The high volume of medical images is leading

Chia-Chi Teng; Jonathan Mitchell; Christopher Walker; Alex Swan; Cesar Davila; David Howard; Travis Needham

2010-01-01

162

Global Moderate Resolution Imaging Spectroradiometer (MODIS) cloud detection and height evaluation using CALIOP  

NASA Astrophysics Data System (ADS)

A global 2-month comparison is presented between the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and the Moderate Resolution Imaging Spectroradiometer (MODIS) for both cloud detection and cloud top height (CTH) retrievals. Both CALIOP and MODIS are part of the NASA A-Train constellation of satellites and provide continuous near-coincident measurements that result in over 28 million cloud detection comparisons and over 5 million CTH comparisons for the months of August 2006 and February 2007. To facilitate the comparison, a computationally efficient and accurate collocation methodology is developed. With the collocated MODIS and CALIOP retrievals, nearly instantaneous comparisons are compiled regionally and globally. Globally, it is found that the MODIS 1-km cloud mask and the CALIOP 1-km averaged layer product agreement is 87% for cloudy conditions for both August 2006 and February 2007. For clear-sky conditions the agreement is 85% (86%) for August (February). The best agreement is found for nonpolar daytime and the poorest agreement in the polar regions. Differences in cloud top heights depend strongly on cloud type. Globally, MODIS underestimates the CTH relative to CALIOP by 1.4 ± 2.9 km for both August 2006 and February 2007. This value of 1.4 km is obtained using the CALIOP 1 km layer products. When compared to the CALIOP 5-km products, the differences increase to -2.6 ± 3.9 km as a result of CALIOP's increased sensitivity to optically thin cirrus. When only high clouds above 5 km are considered, the differences are found to be greater than 4 km with individual comparisons having differences larger than 10 km. These large differences (>10 km) represent approximately 16% of the nonpolar high cloud retrievals (>5 km). For high clouds it is found that MODIS retrieves a cloud top height for 90% of the clouds detected by the CALIOP 5-km layer products. The large MODIS underestimates for optically thin cirrus occur for cases when MODIS reverts to a window brightness temperature retrieval instead of CO2 slicing. A systematic bias is found for marine low-level stratus clouds, with MODIS overestimating the CTH by over 1 km in dense marine stratocumulus regions. The cause of the bias was identified in the MODIS Collection 5 algorithm; an application of a modified algorithm reduced this bias.

Holz, R. E.; Ackerman, S. A.; Nagle, F. W.; Frey, R.; Dutcher, S.; Kuehn, R. E.; Vaughan, M. A.; Baum, B.

2008-04-01

163

Machine learning patterns for neuroimaging-genetic studies in the cloud.  

PubMed

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, Gaël; Brasche, Goetz; Conrod, Patricia; Lemaitre, Herve; Paus, Tomas; Rietschel, Marcella; Frouin, Vincent; Poline, Jean-Baptiste; Antoniu, Gabriel; Thirion, Bertrand

2014-01-01

164

Cassini Imaging of Titan's North Polar Cloud With the Visual and Infrared Mapping Spectrometer  

Microsoft Academic Search

We report on the Visual and Infrared Mapping Spectrometer (VIMS) observations of a giant cloud over the north pole of Titan. Griffith et al. [Science, 2006] described the first evidence of a north polar feature having the form of an ubiquitous bright band at 51° to 68°N in VIMS images acquired in December 2004, August and September 2005. Rodriguez et

S. Le Mouélic; P. Rannou; S. Rodriguez; C. Sotin; L. Le Corre; J. W. Barnes; R. H. Brown; C. A. Griffith; K. H. Baines; B. J. Buratti; R. N. Clark; P. Nicholson

2009-01-01

165

Automatic Registration of Terrestrial Laser Scanning Point Clouds using Panoramic Reflectance Images  

PubMed Central

This paper presents a new approach to the automatic registration of terrestrial laser scanning (TLS) point clouds using panoramic reflectance images. The approach follows a two-step procedure that includes both pair-wise registration and global registration. The pair-wise registration consists of image matching (pixel-to-pixel correspondence) and point cloud registration (point-to-point correspondence), as the correspondence between the image and the point cloud (pixel-to-point) is inherent to the reflectance images. False correspondences are removed by a geometric invariance check. The pixel-to-point correspondence and the computation of the rigid transformation parameters (RTPs) are integrated into an iterative process that allows for the pair-wise registration to be optimised. The global registration of all point clouds is obtained by a bundle adjustment using a circular self-closure constraint. Our approach is tested with both indoor and outdoor scenes acquired by a FARO LS 880 laser scanner with an angular resolution of 0.036° and 0.045°, respectively. The results show that the pair-wise and global registration accuracies are of millimetre and centimetre orders, respectively, and that the process is fully automatic and converges quickly. PMID:22574036

Kang, Zhizhong; Li, Jonathan; Zhang, Liqiang; Zhao, Qile; Zlatanova, Sisi

2009-01-01

166

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 obtained by the Cooled Mid-Infrared Camera and Spectrometer (COMICS), mounted on the 8.2-m Subaru Telescope. In this presentation, we will overview the observational results and discuss their interpretations.

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

2014-04-01

167

Antenna Pattern Synthesis and Deconvolution of Microwave Radiometer Imaging Data  

E-print Network

Antenna Pattern Synthesis and Deconvolution of Microwave Radiometer Imaging Data C. T. Swift, M. A. Introduction A microwave radiometer measures the actual thermal emission smoothed by the radiation power radiometers. The first conically scanned space borne radiometer system for earth remote sensing was the SMMR

Reising, Steven C.

168

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

169

CCD camera response to diffraction patterns simulating particle images.  

PubMed

We present a statistical study of CCD (or CMOS) camera response to small images. Diffraction patterns simulating particle images of a size around 2-3 pixels were experimentally generated and characterized using three-point Gaussian peak fitting, currently used in particle image velocimetry (PIV) for accurate location estimation. Based on this peak-fitting technique, the bias and RMS error between locations of simulated and real images were accurately calculated by using a homemade program. The influence of the intensity variation of the simulated particle images on the response of the CCD camera was studied. The experimental results show that the accuracy of the position determination is very good and brings attention to superresolution PIV algorithms. Some tracks are proposed in the conclusion to enlarge and improve the study. PMID:23842270

Stanislas, M; Abdelsalam, D G; Coudert, S

2013-07-01

170

A pattern similarity scheme for medical image retrieval.  

PubMed

In this paper, we propose a novel scheme for efficient content-based medical image retrieval, formalized according to the PAtterns for Next generation DAtabase systems (PANDA) framework for pattern representation and management. The proposed scheme involves block-based low-level feature extraction from images followed by the clustering of the feature space to form higher-level, semantically meaningful patterns. The clustering of the feature space is realized by an expectation-maximization algorithm that uses an iterative approach to automatically determine the number of clusters. Then, the 2-component property of PANDA is exploited: the similarity between two clusters is estimated as a function of the similarity of both their structures and the measure components. Experiments were performed on a large set of reference radiographic images, using different kinds of features to encode the low-level image content. Through this experimentation, it is shown that the proposed scheme can be efficiently and effectively applied for medical image retrieval from large databases, providing unsupervised semantic interpretation of the results, which can be further extended by knowledge representation methodologies. PMID:19273018

Iakovidis, Dimitris K; Pelekis, Nikos; Kotsifakos, Evangelos E; Kopanakis, Ioannis; Karanikas, Haralampos; Theodoridis, Yannis

2009-07-01

171

Evaluating EUV mask pattern imaging with two EUV microscopes  

SciTech Connect

Aerial image measurement plays a key role in the development of patterned reticles for each generation of lithography. Studying the field transmitted (reflected) from EUV masks provides detailed information about potential disruptions caused by mask defects, and the performance of defect repair strategies, without the complications of photoresist imaging. Furthermore, by measuring the continuously varying intensity distribution instead of a thresholded, binary resist image, aerial image measurement can be used as feedback to improve mask and lithography system modeling methods. Interest in EUV, at-wavelength, aerial image measurement lead to the creation of several research tools worldwide. These tools are used in advanced mask development work, and in the evaluation of the need for commercial at-wavelength inspection tools. They describe performance measurements of two such tools, inspecting the same EUV mask in a series of benchmarking tests that includes brightfield and darkfield patterns. One tool is the SEMATECH Berkeley Actinic Inspection Tool (AIT) operating on a bending magnet beamline at Lawrence Berkeley National Laboratory's Advanced Light Source. The AIT features an EUV Fresnel zoneplate microscope that emulates the numerical aperture of a 0.25-NA stepper, and projects the aerial image directly onto a CCD camera, with 700x magnification. The second tool is an EUV microscope (EUVM) operating at the NewSUBARU synchrotron in Hyogo, Japan. The NewSUBARU tool projects the aerial image using a reflective, 30x Schwarzschild objective lens, followed by a 10-200x x-ray zooming tube. The illumination conditions and the imaging etendue are different for the two tools. The benchmarking measurements were used to determine many imaging and performance properties of the tools, including resolution, modulation transfer function (MTF), aberration magnitude, aberration field-dependence (including focal-plane tilt), illumination uniformity, line-edge roughness, and flare. These measurements reveal the current state of the art in at-wavelength inspection performance, and will be a useful reference as performance improves over time.

Goldberg, Kenneth A.; Takase, Kei; Naulleau, Patrick P.; Han, Hakseung; Barty, Anton; Kinoshita, Hiroo; Hamamoto, Kazuhiro

2008-02-26

172

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

173

Segmentation of UAV-based images incorporating 3D point cloud information  

NASA Astrophysics Data System (ADS)

Numerous applications related to urban scene analysis demand automatic recognition of buildings and distinct sub-elements. For example, if LiDAR data is available, only 3D information could be leveraged for the segmentation. However, this poses several risks, for instance, the in-plane objects cannot be distinguished from their surroundings. On the other hand, if only image based segmentation is performed, the geometric features (e.g., normal orientation, planarity) are not readily available. This renders the task of detecting the distinct sub-elements of the building with similar radiometric characteristic infeasible. In this paper the individual sub-elements of buildings are recognized through sub-segmentation of the building using geometric and radiometric characteristics jointly. 3D points generated from Unmanned Aerial Vehicle (UAV) images are used for inferring the geometric characteristics of roofs and facades of the building. However, the image-based 3D points are noisy, error prone and often contain gaps. Hence the segmentation in 3D space is not appropriate. Therefore, we propose to perform segmentation in image space using geometric features from the 3D point cloud along with the radiometric features. The initial detection of buildings in 3D point cloud is followed by the segmentation in image space using the region growing approach by utilizing various radiometric and 3D point cloud features. The developed method was tested using two data sets obtained with UAV images with a ground resolution of around 1-2 cm. The developed method accurately segmented most of the building elements when compared to the plane-based segmentation using 3D point cloud alone.

Vetrivel, A.; Gerke, M.; Kerle, N.; Vosselman, G.

2015-03-01

174

Mitigating illumination gradients in a SAR image based on the image data and antenna beam pattern  

DOEpatents

Illumination gradients in a synthetic aperture radar (SAR) image of a target can be mitigated by determining a correction for pixel values associated with the SAR image. This correction is determined based on information indicative of a beam pattern used by a SAR antenna apparatus to illuminate the target, and also based on the pixel values associated with the SAR image. The correction is applied to the pixel values associated with the SAR image to produce corrected pixel values that define a corrected SAR image.

Doerry, Armin W.

2013-04-30

175

Extracting Mobile Objects in Images Using a Velodyne LIDAR Point Cloud  

NASA Astrophysics Data System (ADS)

This paper presents a full pipeline to extract mobile objects in images based on a simultaneous laser acquisition with a Velodyne scanner. The point cloud is first analysed to extract mobile objects in 3D. This is done using Dempster-Shafer theory and it results in weights telling for each points if it corresponds to a mobile object, a fixed object or if no decision can be made based on the data (unknown). These weights are projected in an image acquired simultaneously and used to segment the image between the mobile and the static part of the scene.

Vallet, B.; Xiao, W.; Brédif, M.

2015-03-01

176

Effects of clouds on the Earth radiation budget; Seasonal and inter-annual patterns  

NASA Technical Reports Server (NTRS)

Seasonal and regional variations of clouds and their effects on the climatological parameters were studied. The climatological parameters surface temperature, solar insulation, short-wave absorbed, long wave emitted, and net radiation were considered. The data of climatological parameters consisted of about 20 parameters of Earth radiation budget and clouds of 2070 target areas which covered the globe. It consisted of daily and monthly averages of each parameter for each target area for the period, Jun. 1979 - May 1980. Cloud forcing and black body temperature at the top of the atmosphere were calculated. Interactions of clouds, cloud forcing, black body temperature, and the climatological parameters were investigated and analyzed.

Dhuria, Harbans L.

1992-01-01

177

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

NASA Astrophysics Data System (ADS)

Observations with the Cherenkov telescopes are in principle limited to 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 that 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 ?-ray and proton initiated showers in real data. We show, that the high level of the night sky background effects the selection efficiency of the ?-ray initiated showers. However, application of the higher image-cleaning level significantly improves expected quality factors. The estimated ?-ray selection efficiency for the detector with the camera field of view (FOV) limited to 8{^\\circ } is slightly better than for the camera with an unlimited FOV, although the number of identified ?-ray events is lower. We conclude that large Cherenkov telescopes with large FOV cameras can be used for observations of very high energy ?-rays in the presence of clouds. Consequently, the amount of useful data can be significantly enlarged.

Sobczy?ska, Dorota; Bednarek, W?odek

2014-12-01

178

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

179

Multi-Scale Fractal Analysis of Image Texture and Pattern  

NASA Technical Reports Server (NTRS)

Fractals embody important ideas of self-similarity, in which the spatial behavior or appearance of a system is largely independent of scale. Self-similarity is defined as a property of curves or surfaces where each part is indistinguishable from the whole, or where the form of the curve or surface is invariant with respect to scale. An ideal fractal (or monofractal) curve or surface has a constant dimension over all scales, although it may not be an integer value. This is in contrast to Euclidean or topological dimensions, where discrete one, two, and three dimensions describe curves, planes, and volumes. Theoretically, if the digital numbers of a remotely sensed image resemble an ideal fractal surface, then due to the self-similarity property, the fractal dimension of the image will not vary with scale and resolution. However, most geographical phenomena are not strictly self-similar at all scales, but they can often be modeled by a stochastic fractal in which the scaling and self-similarity properties of the fractal have inexact patterns that can be described by statistics. Stochastic fractal sets relax the monofractal self-similarity assumption and measure many scales and resolutions in order to represent the varying form of a phenomenon as a function of local variables across space. In image interpretation, pattern is defined as the overall spatial form of related features, and the repetition of certain forms is a characteristic pattern found in many cultural objects and some natural features. Texture is the visual impression of coarseness or smoothness caused by the variability or uniformity of image tone or color. A potential use of fractals concerns the analysis of image texture. In these situations it is commonly observed that the degree of roughness or inexactness in an image or surface is a function of scale and not of experimental technique. The fractal dimension of remote sensing data could yield quantitative insight on the spatial complexity and information content contained within these data. A software package known as the Image Characterization and Modeling System (ICAMS) was used to explore how fractal dimension is related to surface texture and pattern. The ICAMS software was verified using simulated images of ideal fractal surfaces with specified dimensions. The fractal dimension for areas of homogeneous land cover in the vicinity of Huntsville, Alabama was measured to investigate the relationship between texture and resolution for different land covers.

Emerson, Charles W.

1998-01-01

180

Etiology of the obstructive pattern in hepatobiliary imaging  

SciTech Connect

The records of all patients undergoing hepatobiliary imaging with technetion radioisotopes at our hospital from January 1980 to March 1983 were reviewed and 29 scans met the criteria for a pattern consistent with complete biliary tract obstruction. Biliary tract obstruction (due to choledocholithiasis, primary or secondary carcinoma involving the common bile duct, and pancreatitis) was documented in 24 of these patients. However, the remaining five patients had a patent common bile duct, and the etiologic factor was intrahepatic cholestasis secondary to sepsis in four and peritonitis in one. A classification of altered biliary dynamics in hepatobiliary imaging, which is based on the classification of jaundice, is proposed.

Hughes, K.S.; Marrangoni, A.G.; Turbiner, E.

1984-04-01

181

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

182

Proceedings of the Second Annual Symposium on Mathematical Pattern Recognition and Image Analysis Program  

NASA Technical Reports Server (NTRS)

Several papers addressing image analysis and pattern recognition techniques for satellite imagery are presented. Texture classification, image rectification and registration, spatial parameter estimation, and surface fitting are discussed.

Guseman, L. F., Jr. (principal investigator)

1984-01-01

183

The study of a linear optimal location the typhoon center automatic from IR satellite cloud image  

NASA Astrophysics Data System (ADS)

The typhoon center location is important for forecast typhoon path and harmful weather. However, the appearance of the typhoon from satellite cloud images was very complex and stochastic. Some location methods were short of robustness and oneness. In order to locate the typhoon center automatically and accurately, we propose a linear optimal location technique based on the feature of typhoon cloud circumgyrate the typhoon center. Grounded on the feature ,we extracted the typhoon swirl feature using eigenvector which is denoted by the tangent of typhoon cloud image's gray gradient. Then, we gain the solution of location optimal target equation using genetic algorithms, but this method has the disadvantages of slow convergence and poor stability ,so an improved genetic algorithm is proposed in terms of creation of the initial population and genetic operators. In the end, comparing general genetic algorithm with improved genetic algorithm in convergence. We applied our approach to locate the center of some different typhoons occurred in 2008, from the results of simulation experiments, we conclude that the method presented cloud identify the typhoon center feature easily and locate the typhoon center accurately. Theory analysis and experiment shows the method is reasonable and efficient.

Li, Yan; Chen, Xi; Fei, Shu-ming; Mao, Ke-Feng; Zhou, Kai

2011-08-01

184

Analysis of breathing air flow patterns in thermal imaging.  

PubMed

We introduce a novel methodology to characterize breathing patterns based on thermal infrared imaging. We have retrofitted a Mid-Wave Infra-Red (MWIR) imaging system with a narrow band-pass filter in the CO(2) absorption band (4130 - 4427 nm). We use this system to record the radiation information from within the breathing flow region. Based on this information we compute the mean dynamic thermal signal of breath. The breath signal is quasi-periodic due to the interleaving of high and low intensities corresponding to expirations and inspirations respectively. We sample the signal at a constant rate and then filter the high frequency noise due to tracking instability. We detect the breathing cycles through zero cross thresholding, which is insensitive to noise around the zero line. We normalize the breathing cycles and align them at the transition point from inhalation to exhalation. Then, we compute the mean breathing cycle. We use the first eight (8) harmonic components of the mean cycle to characterize the breathing pattern. The harmonic analysis highlights the intra-individual similarity of breathing patterns. Our method opens the way for desktop, unobtrusive monitoring of human respiration and may find widespread applications in clinical studies of chronic ailments. It also brings up the intriguing possibility of using breathing patterns as a novel biometric. PMID:17945610

Fei, Jin; Pavlidis, Ioannis

2006-01-01

185

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

186

An objective regional cloud mask algorithm for GOES infrared imager radiance assimilation  

NASA Astrophysics Data System (ADS)

A local, regime-dependent cloud mask (CM) algorithm is developed for isolating cloud-free pixels from cloudy pixels for Geostationary Operational Environmental Satellite (GOES) imager radiance assimilation using mesoscale forecast models. In this CM algorithm, thresholds for six different CM tests are determined by a one-dimensional optimization approach based on probability distribution functions of the nearby cloudy and clear-sky pixels within a 10° × 10° box centered at a target pixel. It is shown that the optimizal thresholds over land are, in general, larger and display more spatial variations than over ocean. The performance of the proposed CM algorithm is compared with Moderate Resolution Imaging Spectroradiometer (MODIS) CM for a 1 week period from 19 to 23 May 2008. Based on MODIS CM results, the average Probability of Correct Typing reaches 92.94% and 91.50% over land and ocean, respectively.

Zou, Xiaolei; Da, Cheng

2014-06-01

187

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

188

Space Telescope Imaging Spectrograph Observations of Interstellar Oxygen and Krypton in Translucent Clouds  

Microsoft Academic Search

We have obtained high-resolution Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations of O I lambda1356 and Kr I lambda1236 absorption in 11 sight lines characterized by high extinction, large H I column densities, and\\/or long path lengths. Previous Goddard High Resolution Spectrograph (GHRS) measurements of these weak features in seven relatively nearby diffuse clouds have shown no

Stefan I. B. Cartledge; David M. Meyer; J. T. Lauroesch; U. J. Sofia

2001-01-01

189

MODIS-derived daily PAR simulation from cloud-free images and its validation  

Microsoft Academic Search

In this paper, a MODIS-derived daily PAR (photosynthetically active radiation) simulation model from cloud-free image over land surface has been developed based on Bird and Riordan’s model. In this model, the total downwelling spectral surface irradiance is divided into two parts: one is beam irradiance, and another is diffuse irradiance. The attenuation of solar beam irradiance comprises scattering by the

Liangfu Chen; Yanhua Gao; Lei Yang; Qinhuo Liu; Xingfa Gu; Guoliang Tian

2008-01-01

190

Synergistic use of Imager Window observations for Cloud Clearing of Sounder Observation for INSAT-3D  

NASA Astrophysics Data System (ADS)

The retrieval of atmospheric temperature and water vapor profiles from infrared Sounder are severely limited by the presence of cloud. Therefore, retrieval from infrared sounding observations is performed only over clear-sky atmospheric conditions. The probability of finding a clear-sky pixel at spatial resolution of 10 km is found to be very small globally. This study presents a quantitative analysis of the clear-sky probability that is carried out for different months over the Indian region for INSAT-3D Sounder. The probability of a clear-sky is found to be ~7 % for the field of view of 10 km corresponding to the INSAT-3D Sounder. This statistical analysis is established using MODIS cloud mask having 95 % confidence level at 1 km resolution spread in the region between 50E-110E and 30S-30N. This necessitates cloud clearing to remove the effect of partial clouds in the Sounder FOV to provide a clear-sky equivalent sounding retrieval. Various methods were explored to derive the cloud-cleared radiances using supplementary information such as high resolution infrared or microwave observations. This study presents an effort to use the existing traditional method to derive optimal cloudcleared radiances for INSAT-3D Sounder, by estimating the fractional cloud cover using collocated high resolution INSAT-3D Imager window channel observation. The final Sounder cloud-cleared radiances have been validated with the operational AIRS L2 cloud-cleared radiance products. Nevertheless, the statistical analysis of clear-sky probability over Indian region also provides a significant insight towards the dependency of spatial resolution and the considerable field-of-regard (FOR) in obtaining the clear-sky area in the satellite observations. This, in a way, necessitates the cloud-clearing for coarser resolution sensors and at the same time, states the benefits of using very high resolution sensors. It has been observed that FOV of 1km and by choosing a reasonably good FOR can eliminate the cloudy-sky hindrances by increasing the probability of clear-sky from 5 % to 50 %.

Satapathy, J.; Thapliyal, P. K.; Shukla, M. V.; Kishtawal, C. M.

2014-11-01

191

Retrieval of Cloud Phase Using the Moderate Resolution Imaging Spectroradiometer Data during the Mixed-Phase Arctic Cloud Experiment  

SciTech Connect

Improving climate model predictions over Earth's polar regions requires a comprehensive knowledge of polar cloud microphysics. Over the Arctic, there is minimal contrast between the clouds and background snow surface, making it difficult to detect clouds and retrieve their phase from space. Snow and ice cover, temperature inversions, and the predominance of mixed-phase clouds make it even more difficult to determine cloud phase. Also, since determining cloud phase is the first step toward analyzing cloud optical depth, particle size, and water content, it is vital that the phase be correct in order to obtain accurate microphysical and bulk properties. Changes in these cloud properties will, in turn, affect the Arctic climate since clouds are expected to play a critical role in the sea ice albedo feedback. In this paper, the IR trispectral technique (IRTST) is used as a starting point for a WV and 11-{micro}m brightness temperature (T11) parameterization (WVT11P) of cloud phase using MODIS data. In addition to its ability to detect mixed-phase clouds, the WVT11P also has the capability to identify thin cirrus clouds overlying mixed or liquid phase clouds (multiphase ice). Results from the Atmospheric Radiation Measurement (ARM) MODIS phase model (AMPHM) are compared to the surface-based cloud phase retrievals over the ARM North Slope of Alaska (NSA) Barrow site and to in-situ data taken from University of North Dakota Citation (CIT) aircraft which flew during the Mixed-Phase Arctic Cloud Experiment (MPACE). It will be shown that the IRTST and WVT11P combined to form the AMPHM can achieve a relative high accuracy of phase discrimination compared to the surface-based retrievals. Since it only uses MODIS WV and IR channels, the AMPHM is robust in the sense that it can be applied to daytime, twilight, and nighttime scenes with no discontinuities in the output phase.

Spangenberg, D.; Minnis, P.; Shupe, M.; Uttal, T.; Poellot, M.

2005-03-18

192

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

193

Classification of texture patterns in CT lung imaging  

NASA Astrophysics Data System (ADS)

Since several lung diseases can be potentially diagnosed based on the patterns of lung tissue observed in medical images, automated texture classification can be useful in assisting the diagnosis. In this paper, we propose a methodology for discriminating between various types of normal and diseased lung tissue in computed tomography (CT) images that utilizes Vector Quantization (VQ), an image compression technique, to extract discriminative texture features. Rather than focusing on images of the entire lung, we direct our attention to the extraction of local descriptors from individual regions of interest (ROIs) as determined by domain experts. After determining the ROIs, we generate "locally optimal" codebooks representing texture features of each region using the Generalized Lloyd Algorithm. We then utilize the codeword usage frequency of each codebook as a discriminative feature vector for the region it represents. We compare k-nearest neighbor, support vector machine and neural network classification approaches using the normalized histogram intersection as a similarity measure. The classification accuracy reached up to 98% for certain experimental settings, indicating that our approach may potentially assist clinicians in the interpretation of lung images and facilitate the investigation of relationships among structure, texture and function or pathology related to several lung diseases.

Nuzhnaya, Tatyana; Megalooikonomou, Vasileios; Ling, Haibin; Kohn, Mark; Steiner, Robert

2011-03-01

194

On dictionary adaptation for recurrent pattern image coding.  

PubMed

In this paper, we exploit a recently introduced coding algorithm called multidimensional multiscale parser (MMP) as an alternative to the traditional transform quantization-based methods. MMP uses approximate pattern matching with adaptive multiscale dictionaries that contain concatenations of scaled versions of previously encoded image blocks. We propose the use of predictive coding schemes that modify the source's probability distribution, in order to favour the efficiency of MMP's dictionary adaptation. Statistical conditioning is also used, allowing for an increased coding efficiency of the dictionaries' symbols. New dictionary design methods, that allow for an effective compromise between the introduction of new dictionary elements and the reduction of codebook redundancy, are also proposed. Experimental results validate the proposed techniques by showing consistent improvements in PSNR performance over the original MMP algorithm. When compared with state-of-the-art methods, like JPEG2000 and H.264/AVC, the proposed algorithm achieves relevant gains (up to 6 dB) for nonsmooth images and very competitive results for smooth images. These results strongly suggest that the new paradigm posed by MMP can be regarded as an alternative to the one traditionally used in image coding, for a wide range of image types. PMID:18701400

Rodrigues, Nuno M M; da Silva, Eduardo A B; de Carvalho, Murilo B; de Faria, Sérgio M M; da Silva, Vitor M M

2008-09-01

195

Faxed document image restoration method based on local pixel patterns  

NASA Astrophysics Data System (ADS)

A method for restoring degraded faxed document images using the patterns of pixels that construct small areas in a document is proposed. The method effectively restores faxed images that contain the halftone textures and/or density salt-and-pepper noise that degrade OCR system performance. The halftone image restoration process, white-centered 3 X 3 pixels, in which black-and-white pixels alternate, are identified first using the distribution of the pixel values as halftone textures, and then the white center pixels are inverted to black. To remove high-density salt- and-pepper noise, it is assumed that the degradation is caused by ill-balanced bias and inappropriate thresholding of the sensor output which results in the addition of random noise. Restored image can be estimated using an approximation that uses the inverse operation of the assumed original process. In order to process degraded faxed images, the algorithms mentioned above are combined. An experiment is conducted using 24 especially poor quality examples selected from data sets that exemplify what practical fax- based OCR systems cannot handle. The maximum recovery rate in terms of mean square error was 98.8 percent.

Akiyama, Teruo; Miyamoto, Nobuo; Oguro, Masami; Ogura, Kenji

1998-04-01

196

Graphene electrically reconfigurable patterns for THz imaging applications  

NASA Astrophysics Data System (ADS)

THz waves are attractive for several imaging applications, since they can propagate through non metallic media such as paper, cloth, plastics, and ceramics, and do not scatter over nano-scale defects or ionize the material under imaging -as might shorter wavelengths do- while offering an image resolution similar to that of the human eye. In this work we propose and experimentally demonstrate electrically reconfigurable patterns for single-pixel terahertz imaging based on arrays of graphene THz electro-absorption modulators. In an optical setup, in conjunction with mirrors, the modulator array can transform the output radiation from a CW THz source into a pixelated and collimated beam of illumination. Single-atom-thick graphene is employed as the active element of these modulators, achieving a modulation of the THz wave reflectance 50% with a potential modulation depth approaching 100% (i.e. each region of the pixelated collimated beam can be potentially completely turned-off). Although the proof-of-concept device here discussed only consists of 4x4 elements, we foresee that this technology can enable low-cost video rate THz imaging systems.

Sensale-Rodriguez, Berardi; Rafique, Subrina; Yan, Rusen; Zhu, Mingda; Protasenko, Vladimir; Jena, Debdeep; Liu, Lei; Xing, Huili Grace

2013-03-01

197

CIMIDx: Prototype for a Cloud-Based System to Support Intelligent Medical Image Diagnosis With Efficiency  

PubMed Central

Background The Internet has greatly enhanced health care, helping patients stay up-to-date on medical issues and general knowledge. Many cancer patients use the Internet for cancer diagnosis and related information. Recently, cloud computing has emerged as a new way of delivering health services but currently, there is no generic and fully automated cloud-based self-management intervention for breast cancer patients, as practical guidelines are lacking. Objective We investigated the prevalence and predictors of cloud use for medical diagnosis among women with breast cancer to gain insight into meaningful usage parameters to evaluate the use of generic, fully automated cloud-based self-intervention, by assessing how breast cancer survivors use a generic self-management model. The goal of this study was implemented and evaluated with a new prototype called “CIMIDx”, based on representative association rules that support the diagnosis of medical images (mammograms). Methods The proposed Cloud-Based System Support Intelligent Medical Image Diagnosis (CIMIDx) prototype includes two modules. The first is the design and development of the CIMIDx training and test cloud services. Deployed in the cloud, the prototype can be used for diagnosis and screening mammography by assessing the cancers detected, tumor sizes, histology, and stage of classification accuracy. To analyze the prototype’s classification accuracy, we conducted an experiment with data provided by clients. Second, by monitoring cloud server requests, the CIMIDx usage statistics were recorded for the cloud-based self-intervention groups. We conducted an evaluation of the CIMIDx cloud service usage, in which browsing functionalities were evaluated from the end-user’s perspective. Results We performed several experiments to validate the CIMIDx prototype for breast health issues. The first set of experiments evaluated the diagnostic performance of the CIMIDx framework. We collected medical information from 150 breast cancer survivors from hospitals and health centers. The CIMIDx prototype achieved high sensitivity of up to 99.29%, and accuracy of up to 98%. The second set of experiments evaluated CIMIDx use for breast health issues, using t tests and Pearson chi-square tests to assess differences, and binary logistic regression to estimate the odds ratio (OR) for the predictors’ use of CIMIDx. For the prototype usage statistics for the same 150 breast cancer survivors, we interviewed 114 (76.0%), through self-report questionnaires from CIMIDx blogs. The frequency of log-ins/person ranged from 0 to 30, total duration/person from 0 to 1500 minutes (25 hours). The 114 participants continued logging in to all phases, resulting in an intervention adherence rate of 44.3% (95% CI 33.2-55.9). The overall performance of the prototype for the good category, reported usefulness of the prototype (P=.77), overall satisfaction of the prototype (P=.31), ease of navigation (P=.89), user friendliness evaluation (P=.31), and overall satisfaction (P=.31). Positive evaluations given by 100 participants via a Web-based questionnaire supported our hypothesis. Conclusions The present study shows that women felt favorably about the use of a generic fully automated cloud-based self- management prototype. The study also demonstrated that the CIMIDx prototype resulted in the detection of more cancers in screening and diagnosing patients, with an increased accuracy rate. PMID:25830608

2015-01-01

198

Venus in motion: An animated video catalog of Pioneer Venus Orbiter Cloud Photopolarimeter images  

NASA Technical Reports Server (NTRS)

Images of Venus acquired by the Pioneer Venus Orbiter Cloud Photopolarimeter (OCPP) during the 1982 opportunity have been utilized to create a short video summary of the data. The raw roll by roll images were first navigated using the spacecraft attitude and orbit information along with the CPP instrument pointing information. The limb darkening introduced by the variation of solar illumination geometry and the viewing angle was then modelled and removed. The images were then projected to simulate a view obtained from a fixed perspective with the observer at 10 Venus radii away and located above a Venus latitude of 30 degrees south and a longitude 60 degrees west. A total of 156 images from the 1982 opportunity have been animated at different dwell rates.

Limaye, Sanjay S.

1992-01-01

199

Space Telescope Imaging Spectrograph Observations of Interstellar Oxygen and Krypton in Translucent Clouds  

NASA Astrophysics Data System (ADS)

We have obtained high-resolution Hubble Space Telescope (HST) Space Telescope Imaging Spectrograph (STIS) observations of O I ?1356 and Kr I ?1236 absorption in 11 sight lines characterized by high extinction, large H I column densities, and/or long path lengths. Previous Goddard High Resolution Spectrograph (GHRS) measurements of these weak features in seven relatively nearby diffuse clouds have shown no evidence for density-dependent depletion of either oxygen or krypton and have yielded a weighted mean gas-phase abundance ratio of log[N(O)/N(Kr)]GHRS=5.56+/-0.04. Our STIS measurements yield a lower weighted mean of log[N(O)/N(Kr)]STIS=5.48 the difference is due primarily to several translucent sight lines in the STIS data set that diverge from the GHRS value. These translucent cloud sight lines pass near dense, star-forming regions, notably the ? Oph, Orion, and Taurus molecular clouds. Since Kr, as a noble gas, should not be depleted much into grains, these cases suggest a trend toward the enhanced oxygen depletion predicted for denser ISM clouds. Based on observations 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, Inc. under NASA contract NAS 5-26555.

Cartledge, Stefan I. B.; Meyer, David M.; Lauroesch, J. T.; Sofia, U. J.

2001-11-01

200

A fast, robust pattern recognition asystem for low light level image registration and its application to retinal imaging  

NASA Astrophysics Data System (ADS)

We describe an image processing system which we have developed to align autofluorescence and high-magnification images taken with a laser scanning ophthalmoscope. The low signal to noise ratio of these images makes pattern recognition a non-trivial task. However, once n images are aligned and averaged, the noise levels drop by a factor of n and the image quality is improved. We include examples of autofluorescence images and images of the cone photoreceptor mosaic obtained using this system.

Wade, Alex Robert; Fitzke, Frederick W.

1998-08-01

201

A fast, robust pattern recognition asystem for low light level image registration and its application to retinal imaging.  

PubMed

We describe an image processing system which we have developed to align autofluorescence and high-magnification images taken with a laser scanning ophthalmoscope. The low signal to noise ratio of these images makes pattern recognition a non-trivial task. However, once n images are aligned and averaged, the noise levels drop by a factor of n and the image quality is improved. We include examples of autofluorescence images and images of the cone photoreceptor mosaic obtained using this system. PMID:19384360

Wade, A; Fitzke, F

1998-08-31

202

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

203

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

204

Two Methods for Retrieving UV Index for All Cloud Conditions from Sky Imager Products or Total SW Radiation Measurements  

SciTech Connect

In the present study, we assess the cloud effects on UV Index (UVI) and total solar radiation (TR) as a function of cloud cover estimations and sunny conditions (from sky imaging products) as well as of solar zenith angle (SZA). 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 (> 60º). Similarly, clouds enhance TR more than 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 operational applications, although Method 2 shows overall the best performance, since TR allows accounting for cloud optical properties. The mean absolute differences of Method 2 estimations with respect to measured values are 0.17 UVI units (for 1-minute data) and 0.79 Standard Erythemal Dose (SED) units (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 and 1.6 SED.

Badosa, Jordi; Calbo, J.; McKenzie, R. L.; Liley, Ben; Gonzalez, J. A.; Forgan, B. W.; Long, Charles N.

2014-07-01

205

Imaging of Flow Patterns with Fluorescent Molecular Rotors  

PubMed Central

Molecular rotors are a group of fluorescent molecules that form twisted intramolecular charge transfer states (TICT) upon photoexcitation. Some classes of molecular rotors, among them those that are built on the benzylidene malononitrile motif, return to the ground state either by nonradiative intramolecular rotation or by fluorescence emission. In low-viscosity solvents, intramolecular rotation dominates, and the fluorescence quantum yield is low. Higher solvent viscosities reduce the intramolecular rotation rate, thus increasing the quantum yield. We recently described a different mechanism whereby the fluorescence quantum yield of the molecular rotor also depends on the shear stress of the solvent. In this study, we examined a possible application for shear-sensitive molecular rotors for imaging flow patterns in fluidic chambers. Flow chambers with different geometries were constructed from polycarbonate or acrylic. Solutions of molecular rotors in ethylene glycol were injected into the chamber under controlled flow rates. LED-induced fluorescence (LIF) images of the flow chambers were taken with a digital camera, and the intensity difference between flow and no-flow images was visualized and compared to computed fluid dynamics (CFD) simulations. Intensity differences were detectable with average flow rates as low as 0.1 mm/s, and an exponential association between flow rate and intensity increase was found. Furthermore, a good qualitative match to computed fluid dynamics simulations was seen. On the other hand, prolonged exposure to light reduced the emission intensity. With its high sensitivity and high spatial and temporal resolution, imaging of flow patterns with molecular rotors may become a useful tool in microfluidics, flow measurement, and control. PMID:20405175

Mustafic, Adnan; Huang, Hsuan-Ming; Theodorakis, Emmanuel A.

2010-01-01

206

Diffractive-imaging-based optical image encryption with simplified decryption from single diffraction pattern.  

PubMed

In this paper, we propose a novel method for image encryption by employing the diffraction imaging technique. This method is in principle suitable for most diffractive-imaging-based optical encryption schemes, and a typical diffractive imaging architecture using three random phase masks in the Fresnel domain is taken for an example to illustrate it. The encryption process is rather simple because only a single diffraction intensity pattern is needed to be recorded, and the decryption procedure is also correspondingly simplified. To achieve this goal, redundant data are digitally appended to the primary image before a standard encrypting procedure. The redundant data serve as a partial input plane support constraint in a phase retrieval algorithm, which is employed for completely retrieving the plaintext. Simulation results are presented to verify the validity of the proposed approach. PMID:25089966

Qin, Yi; Wang, Zhipeng; Gong, Qiong

2014-07-01

207

Deep Convective Clouds  

NSDL National Science Digital Library

Convective clouds are clouds that develop vertically appearing like big stacks of clouds. One very common example is cumulonimbus clouds. Convective clouds are commonly connected to stormy weather. Monthly Cloud Coverage for Deep Convective Cloud data can be used to predict patterns in weather. The specific pattern associated with this data is tracking and predicting thunderstorms. In this lesson, the students will take a look at the Monthly Cloud Coverage for Deep Convective Cloud data, and name one month of the year 'Thunderstorm Season' for their continent.

208

The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI): a new tool for aerosol and cloud remote sensing  

NASA Astrophysics Data System (ADS)

The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) is an eight-band (355, 380, 445, 470, 555, 660, 865, 935 nm) pushbroom camera, measuring polarization in the 470, 660, and 865 nm bands, mounted on a gimbal to acquire multiangular observations over a ±67° along-track range. The instrument has been flying aboard the NASA ER-2 high altitude aircraft since October 2010. AirMSPI employs a photoelastic modulator-based polarimetric imaging technique to enable accurate measurements of the degree and angle of linear polarization in addition to spectral intensity. A description of the AirMSPI instrument and ground data processing approach is presented. Example images of clear, hazy, and cloudy scenes over the Pacific Ocean and California land targets obtained during flights between 2010 and 2012 are shown, and quantitative interpretations of the data using vector radiative transfer theory and scene models are provided to highlight the instrument's capabilities for determining aerosol and cloud microphysical properties and cloud 3-D spatial distributions. Sensitivity to parameters such as aerosol particle size distribution, ocean surface wind speed and direction, cloud-top and cloud-base height, and cloud droplet size is discussed. AirMSPI represents a major step toward realization of the type of imaging polarimeter envisioned to fly on NASA's Aerosol-Cloud-Ecosystem (ACE) mission in the next decade.

Diner, D. J.; Xu, F.; Garay, M. J.; Martonchik, J. V.; Rheingans, B. E.; Geier, S.; Davis, A.; Hancock, B. R.; Jovanovic, V. M.; Bull, M. A.; Capraro, K.; Chipman, R. A.; McClain, S. C.

2013-08-01

209

The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI): a new tool for aerosol and cloud remote sensing  

NASA Astrophysics Data System (ADS)

The Airborne Multiangle SpectroPolarimetric Imager (AirMSPI) is an eight-band (355, 380, 445, 470, 555, 660, 865, 935 nm) pushbroom camera, measuring polarization in the 470, 660, and 865 nm bands, mounted on a gimbal to acquire multiangular observations over a ± 67° along-track range. The instrument has been flying aboard the NASA ER-2 high altitude aircraft since October 2010. AirMSPI employs a photoelastic modulator-based polarimetric imaging technique to enable accurate measurements of the degree and angle of linear polarization in addition to spectral intensity. A description of the AirMSPI instrument and ground data processing approach is presented. Example images of clear, hazy, and cloudy scenes over the Pacific Ocean and California land targets obtained during flights between 2010 and 2012 are shown, and quantitative interpretations of the data using vector radiative transfer theory and scene models are provided to highlight the instrument's capabilities for determining aerosol and cloud microphysical properties and cloud 3-D spatial distributions. Sensitivity to parameters such as aerosol particle size distribution, ocean surface wind speed and direction, cloud-top and cloud-base height, and cloud droplet size is discussed. AirMSPI represents a major step toward realization of the type of imaging polarimeter envisioned to fly on NASA's Aerosol-Cloud-Ecosystem (ACE) mission in the next decade.

Diner, D. J.; Xu, F.; Garay, M. J.; Martonchik, J. V.; Rheingans, B. E.; Geier, S.; Davis, A.; Hancock, B. R.; Jovanovic, V. M.; Bull, M. A.; Capraro, K.; Chipman, R. A.; McClain, S. C.

2013-02-01

210

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

211

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

212

A Fast Spatial Patch Blending Algorithm for Artefact Reduction in Pattern-based Image Inpainting  

E-print Network

A Fast Spatial Patch Blending Algorithm for Artefact Reduction in Pattern-based Image Inpainting algorithm for image inpainting. From left to right : color image with area to reconstruct, reconstruction contents from images, known as image inpainting, is a widely used tool today. Movie producers for example

Paris-Sud XI, Université de

213

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

214

Jupiter's polar clouds and waves from Cassini and HST images: 1993 2006  

NASA Astrophysics Data System (ADS)

For a variety of reasons, Jupiter's polar areas are probably the less observed regions of the planet. To study the dynamics and cloud vertical structure in the polar regions of the planet (latitudes 50° to 80° in both hemispheres) we have used images of Jupiter obtained from the ultraviolet to near infrared (258 to 939 nm) by the Cassini Imagining Science Subsystem (ISS) in December 2000. The temporal coverage was complemented with archived images from the Hubble Space Telescope (1993-2006) in a similar spectral range. The zonal wind velocities have been measured at three Cassini ISS wavelengths (CB2, MT3 and UV1, corresponding to 750, 890 and 258 nm) sounding different altitude levels. The three eastward jets detected in CB2 images (lower cloud) go to zero velocity when measured in the UV1 filter (upper haze). A radiative transfer analysis has been performed to characterize the vertical structure of cloud and hazes distribution at the poles. We also present a characterization (phase speed, amplitude and zonal wavenumber) of the previously detected circumpolar waves at 67° N and S at 890 nm and at about 50° N and -57° S at 258 nm that are a permanent phenomenon in Jupiter with some variability in its structure during the analyzed period. From the ensemble of data analyzed we propose the waves are Rossby waves whose dynamic behavior constrains plausible values for their meridional and vertical wavenumbers. This work demonstrates the long-term nature of Jupiter's polar waves, providing a dynamical and vertical characterization which supports a detailed analysis of these phenomena in terms of a Rossby wave model.

Barrado-Izagirre, N.; Sánchez-Lavega, A.; Pérez-Hoyos, S.; Hueso, R.

2008-03-01

215

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

216

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

217

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

218

SKA memo 103, 14 aug 2008 Deconvolving Primary Beam Patterns from SKA Images  

E-print Network

SKA memo 103, 14 aug 2008 Deconvolving Primary Beam Patterns from SKA Images Melvyn Wright present a method for deconvolving the primary beam response from interferometric images of astronomical distribution weighted by the measured primary beam pattern, the residual uv data can be re-imaged to provide

Militzer, Burkhard

219

Teaching image processing and pattern recognition with the Intel OpenCV library  

Microsoft Academic Search

In this paper we present an approach to teaching image processing and pattern recognition with the use of the OpenCV library. Image processing, pattern recognition and computer vision are important branches of science and apply to tasks ranging from critical, involving medical diagnostics, to everyday tasks including art and entertainment purposes. It is therefore crucial to provide students of image

Adam Kozlowski; Aleksandra Królak

2009-01-01

220

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

221

Simplified optical image encryption approach using single diffraction pattern in diffractive-imaging-based scheme.  

PubMed

In previous diffractive-imaging-based optical encryption schemes, it is impossible to totally retrieve the plaintext from a single diffraction pattern. In this paper, we proposed a new method to achieve this goal. The encryption procedure can be completed by proceeding only one exposure, and the single diffraction pattern is recorded as ciphertext. For recovering the plaintext, a novel median-filtering-based phase retrieval algorithm, including two iterative cycles, has been developed. This proposal not only extremely simplifies the encryption and decryption processes, but also facilitates the storage and transmission of the ciphertext, and its effectiveness and feasibility have been demonstrated by numerical simulations. PMID:25321554

Qin, Yi; Gong, Qiong; Wang, Zhipeng

2014-09-01

222

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

NASA Astrophysics Data System (ADS)

Images of measured radiance in different channels of the geostationary Meteosat-9 SEVIRI instrument are analysed with respect to the representativeness of the observations of eight cloud observatories in Europe (e.g. measurements from cloud radars or microwave radiometers). Cloudy situations are selected to get a time series for every pixel in a 300 km × 300 km area centred around each ground station. Then a cross correlation of each time series to the pixel nearest to the corresponding ground site is calculated. In the end a correlation length is calculated to define the representativeness. It is found that measurements in the visible and near infrared channels, which respond to cloud physical properties, 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. This also points to a higher variability of the cloud microphysical properties inside a cloud than of the cloud top temperature. The correlation length even increases for the channels at 6.2, 7.3 and 9.7 ?m. They respond to radiation from the upper atmospheric layers emitted by atmospheric gases and higher level clouds, which are more homogeneous than low-level clouds. Additionally, correlations at different distances, corresponding to the grid box sizes of forecast models, were compared. The results suggest the possibility of comparisons between instantaneous cloud observations from ground sites and regional forecast models and ground-based measurements. For larger distances typical for global models the correlations decrease, especially for short-wave measurements and corresponding cloud products. By comparing daily means, the correlation length 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.

2015-02-01

223

Cloud patterns and mixing properties in shallow moist Rayleigh-Bénard convection  

NASA Astrophysics Data System (ADS)

Three-dimensional direct numerical simulations of idealized moist turbulent Rayleigh-Bénard convection are presented. The thermodynamics of moist air is linearized close to the phase boundary between water vapor and liquid water. This formulation allows for a simplified saturation condition for the cloud formation, but omits supersaturation and rain. The sensitivity of this problem to changes of the Rayleigh number, the aspect ratio of the convection layer and the water vapor concentration is studied. The Rayleigh number is found to impact the behavior of the system in multiple ways. First, the relaxation time toward a well-mixed turbulent state increases with the Rayleigh number. Similarly, the flow exhibits a higher spatial and temporal intermittency at higher Rayleigh number. This is in line with an enhanced intermittency of the upward buoyancy flux, which we quantify by a multifractal analysis. In addition, phase transition introduces an asymmetry in the distribution of the thermodynamic properties of the well-mixed state. This asymmetry is most pronounced in layers where clouds are partially present. Furthermore, the geometrical properties of the cloud formations averaged with respect to the height of the layer are studied. Similar to isocontours in scalar mixing, the boundaries of isolated clouds show no strict (mono-)fractal behavior. The results of the perimeter-area analysis of the largest isolated clouds agree well with those of large eddy simulations of cumulus convection. This perimeter-area scaling is also similar to that of percolation processes in a plane.

Weidauer, Thomas; Pauluis, Olivier; Schumacher, Jörg

2010-10-01

224

A QR code based zero-watermarking scheme for authentication of medical images in teleradiology cloud.  

PubMed

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

225

Integration of Point Clouds Originated from Laser Scaner and Photogrammetric Images for Visualization of Complex Details of Historical Buildings  

NASA Astrophysics Data System (ADS)

Three-dimensional (3D) models of historical buildings are created for documentation and virtual realization of them. Laser scanning and photogrammetry are extensively used to perform for these aims. The selection of the method that will be used in threedimensional modelling study depends on the scale and shape of the object, and also applicability of the method. Laser scanners are high cost instruments. However, the cameras are low cost instruments. The off-the-shelf cameras are used for taking the photogrammetric images. The camera is imaging the object details by carrying on hand while the laser scanner makes ground based measurement. Laser scanner collect high density spatial data in a short time from the measurement area. On the other hand, image based 3D (IB3D) measurement uses images to create 3D point cloud data. The image matching and the creation of the point cloud can be done automatically. Historical buildings include more complex details. Thus, all details cannot be measured by terrestrial laser scanner (TLS) due to the blocking the details with each others. Especially, the artefacts which have complex shapes cannot be measured in full details. They cause occlusion on the point cloud model. However it is possible to record photogrammetric images and creation IB3D point cloud for these areas. Thus the occlusion free 3D model is created by the integration of point clouds originated from the TLS and photogrammetric images. In this study, usability of laser scanning in conjunction with image based modelling for creation occlusion free three-dimensional point cloud model of historical building was evaluated. The IB3D point cloud was created in the areas that could not been measured by TLS. Then laser scanning and IB3D point clouds were integrated in the common coordinate system. The registration point clouds were performed with the iterative closest point (ICP) and georeferencing methods. Accuracy of the registration was evaluated by convergency and its standard deviations for the ICP and residuals on the control points for the georeferencing method.

Altuntas, C.

2015-02-01

226

Calibration and Laboratory Test of the Department of Energy Cloud Particle Imager  

SciTech Connect

Calibration parameters from the Connolly et al. (2007) algorithm cannot be applied to the Department of Energy's (DOE) CPI because the DOE CPI is version 2.0. Thus, Dr. Junshik Um and Prof. Greg McFarquhar brought the DOE CPI to the University of Manchester, UK, where facilities for calibrating it were available. In addition, two other versions of CPIs (1.0 and 1.5) were available on-site at the University of Manchester so that an intercomparison of three different versions of the CPI was possible. The three CPIs (versions 1.0, 1.5, and 2.0) were calibrated by moving glass calibration beads and ice analogues of known size parallel to the object plane. The distance between the object plane and a particle, the particle's focus, its apparent maximum dimension, and a background image were measured in order to derive calibration parameters for each CPI version. The calibration parameters are used in two empirical equations that are applied to in situ CPI data to determine particle size and depth of field, and hence particle size distributions (PSDs). After the tests with the glass calibration beads to derive the calibration parameters, the three CPIs were installed at the base of the Manchester Ice Cloud Chamber and connected to air pumps that drew cloud through the sample volume. Warm liquid clouds at a temperature of 1-2 C and ice clouds at a temperature of -5 C were generated, and the resulting PSDs for each of the CPIs were determined by applying the results of each calibration.

McFarquhar, GM; Um, J

2012-02-17

227

Imaging patterns with 99mTc-PIPIDA in evaluating abdominal pain  

SciTech Connect

A random retrospective review of hepatobiliary scans on 86 adult patients with abdominal pain revealed four distinct imaging patterns: normal, cystic duct obstruction, obstructive, and sick liver pattern. A normal pattern was found to exclude acute cholecystitis and was the pattern most frequently observed.

Curtis, R.F.; Gordon, L.; Selby, J.B. Sr.

1983-11-01

228

Coordinated Imaging and Lidar measurements of Noctilucent Cloud Dynamics over Poker Flat, Alaska, August 2005.  

NASA Astrophysics Data System (ADS)

In conjunction with the 2005 Polar Aeronomy and Radio Science (PARS) Summer School coordinated observations of noctilucent clouds (NLC) were made from central Alaska during August 2005 using imaging and lidar instrumentation. The image measurements was made from a field site near Donnelly Dome (63° N, 145° W) to record NLC over the lidar facility located at Poker Flat Research Range (PFRR) approximately 160 km to the north. A combination of two low-light digital color video cameras and several digital SLR cameras were used to image the NLC field over PFRR using wide and narrow field optics. At the same time NLC observations were made using the NICT Rayleigh lidar to investigate their altitude, structure and backscatter strength. Strong NLC were imaged from Donnelly Dome on three consecutive nights (August 8-10). These events were extensive, filling the northern twilight sky and were observed for over 4 hours. In particular the display of August 9 was very bright and was observed to extend well to the south of PFRR. The lidar measurements on this night were the strongest NLC signal yet recorded at PFRR. In this talk we will present a comparison between the imaging and lidar data focusing on August 9 display which was highly dynamic and observed to split into two distinct layers separated by approximately 1 km after local midnight. The two data sets will be used to study the dynamics of this display.

Nielsen, K.; Taylor, M. J.; Jensen, P. F.; Collins, R. L.; Su, L.; Thurairajah, B.; McDonald, J. G.; Marlow, Z. J.

2005-12-01

229

Modeling, Pattern Analysis and Feature-Based Retrieval on Retinal Images  

E-print Network

texture classification of macular patterns is correlated with vessel structures, which can also be used for retinal image retrieval. The analytical models have been implemented and tested based on various image sources. Some of the algorithms have been...

Ying, Huajun

2012-07-16

230

Wire Structure Pattern Extraction and Tracking From X-Ray Images of composite Mechanisms  

E-print Network

Wire Structure Pattern Extraction and Tracking From X-Ray Images of composite Mechanisms D). Figure 1. One of the acquired X-ray image of a composite sample. The analysis of acquired X-ray images in the acquired 1French Atomic Energy Comission (CEA). 1 #12;image. This is due to the fact that the X-ray system

Tschumperlé, David

231

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

232

Astronomy in the Cloud: Using MapReduce for Image Co-Addition  

NASA Astrophysics Data System (ADS)

In the coming decade, astronomical surveys of the sky will generate tens of terabytes of images and detect hundreds of millions of sources every night. The study of these sources will involve computation challenges such as anomaly detection and classification and moving-object tracking. Since such studies benefit from the highest-quality data, methods such as image co-addition, i.e., astrometric registration followed by per-pixel summation, will be a critical preprocessing step prior to scientific investigation. With a requirement that these images be analyzed on a nightly basis to identify moving sources such as potentially hazardous asteroids or transient objects such as supernovae, these data streams present many computational challenges. Given the quantity of data involved, the computational load of these problems can only be addressed by distributing the workload over a large number of nodes. However, the high data throughput demanded by these applications may present scalability challenges for certain storage architectures. One scalable data-processing method that has emerged in recent years is MapReduce, and in this article we focus on its popular open-source implementation called Hadoop. In the Hadoop framework, the data are partitioned among storage attached directly to worker nodes, and the processing workload is scheduled in parallel on the nodes that contain the required input data. A further motivation for using Hadoop is that it allows us to exploit cloud computing resources: i.e., platforms where Hadoop is offered as a service. We report on our experience of implementing a scalable image-processing pipeline for the SDSS imaging database using Hadoop. This multiterabyte imaging data set provides a good testbed for algorithm development, since its scope and structure approximate future surveys. First, we describe MapReduce and how we adapted image co-addition to the MapReduce framework. Then we describe a number of optimizations to our basic approach and report experimental results comparing their performance.

Wiley, K.; Connolly, A.; Gardner, J.; Krughoff, S.; Balazinska, M.; Howe, B.; Kwon, Y.; Bu, Y.

2011-03-01

233

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

234

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

235

Buildup of electron cloud with different bunch pattern in thepresence of solenoid field  

SciTech Connect

We have augmented the code POSINST to include solenoidfields, and used it to simulate the build up of electron cloud due toelectron multipacting in the PEP-II positron ring. We find that thedistribution of electrons is strongly affected by the resonancesassociated with the cyclotron period and bunch spacing. In addition, wediscover a threshold beyond which the electron density growsexponentially until it reaches the space charge limit. The threshold doesnot depend on the bunch spacing but does depend on the positron bunchpopulation.

Cai, Y.; Pivi (SLAC), M.; Furman (LBNL), M.A.

2003-05-01

236

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

237

Analysis of Breathing Air Flow Patterns in Thermal Imaging Department of Computer Science  

E-print Network

Analysis of Breathing Air Flow Patterns in Thermal Imaging Jin Fei Department of Computer Science a novel methodology to characterize breathing patterns based on thermal infrared imaging. We have band (4130 - 4427 nm). We use this system to record the radiation information from within the breathing

238

Point Cloud Generation from Aerial Image Data Acquired by a Quadrocopter Type Micro Unmanned Aerial Vehicle and a Digital Still Camera  

PubMed Central

The objective of this investigation was to develop and investigate methods for point cloud generation by image matching using aerial image data collected by quadrocopter type micro unmanned aerial vehicle (UAV) imaging systems. Automatic generation of high-quality, dense point clouds from digital images by image matching is a recent, cutting-edge step forward in digital photogrammetric technology. The major components of the system for point cloud generation are a UAV imaging system, an image data collection process using high image overlaps, and post-processing with image orientation and point cloud generation. Two post-processing approaches were developed: one of the methods is based on Bae Systems’ SOCET SET classical commercial photogrammetric software and another is built using Microsoft®’s Photosynth™ service available in the Internet. Empirical testing was carried out in two test areas. Photosynth processing showed that it is possible to orient the images and generate point clouds fully automatically without any a priori orientation information or interactive work. The photogrammetric processing line provided dense and accurate point clouds that followed the theoretical principles of photogrammetry, but also some artifacts were detected. The point clouds from the Photosynth processing were sparser and noisier, which is to a large extent due to the fact that the method is not optimized for dense point cloud generation. Careful photogrammetric processing with self-calibration is required to achieve the highest accuracy. Our results demonstrate the high performance potential of the approach and that with rigorous processing it is possible to reach results that are consistent with theory. We also point out several further research topics. Based on theoretical and empirical results, we give recommendations for properties of imaging sensor, data collection and processing of UAV image data to ensure accurate point cloud generation. PMID:22368479

Rosnell, Tomi; Honkavaara, Eija

2012-01-01

239

Point cloud generation from aerial image data acquired by a quadrocopter type micro unmanned aerial vehicle and a digital still camera.  

PubMed

The objective of this investigation was to develop and investigate methods for point cloud generation by image matching using aerial image data collected by quadrocopter type micro unmanned aerial vehicle (UAV) imaging systems. Automatic generation of high-quality, dense point clouds from digital images by image matching is a recent, cutting-edge step forward in digital photogrammetric technology. The major components of the system for point cloud generation are a UAV imaging system, an image data collection process using high image overlaps, and post-processing with image orientation and point cloud generation. Two post-processing approaches were developed: one of the methods is based on Bae Systems' SOCET SET classical commercial photogrammetric software and another is built using Microsoft(®)'s Photosynth™ service available in the Internet. Empirical testing was carried out in two test areas. Photosynth processing showed that it is possible to orient the images and generate point clouds fully automatically without any a priori orientation information or interactive work. The photogrammetric processing line provided dense and accurate point clouds that followed the theoretical principles of photogrammetry, but also some artifacts were detected. The point clouds from the Photosynth processing were sparser and noisier, which is to a large extent due to the fact that the method is not optimized for dense point cloud generation. Careful photogrammetric processing with self-calibration is required to achieve the highest accuracy. Our results demonstrate the high performance potential of the approach and that with rigorous processing it is possible to reach results that are consistent with theory. We also point out several further research topics. Based on theoretical and empirical results, we give recommendations for properties of imaging sensor, data collection and processing of UAV image data to ensure accurate point cloud generation. PMID:22368479

Rosnell, Tomi; Honkavaara, Eija

2012-01-01

240

Discovery and imaging of a Galactic cirrus cloud with the far ultraviolet space telescope  

NASA Technical Reports Server (NTRS)

We present new far-ultraviolet (1400-1800 A) data concerning a Galactic cirrus cloud G251.2+73.3 near the north Galactic pole obtained with the space-borne imaging telescope FAUST (Far Ultraviolet Space Telescope). We obtain a good correlation between the far-ultraviolet (FUV) and IRAS 100 micrometers surface brightnesses, their relation being I(sub FUV) = (128 +/- 3) I(sub 100 micrometers) - (264 +/- 9), where the I(sub FUV) flux is given in units of photon/s/sq cm/A/sr and I(sub 100 micrometers) in MJy/sr. Using uvbyH-beta photometry, we get a distance of 120 pc and a visual extinction in the center of the cloud of 0.39 mag corresponding to an extinction of 1.0 mag at 1565 A. We have performed a multiple scattering calculation for the scattered light using the Monte Carlo method. These calculations provide restrictions on the FUV scattering properties of the interstellar dust.

Haikala, Lauri K.; Mattila, Kalevi; Bowyer, Stuart; Sasseen, Timothy P.; Lampton, Michael; Knude, Jens

1995-01-01

241

Noctilucent Cloud Imaging and Tomography using a Suborbital Reusable Launch Vehicle  

NASA Astrophysics Data System (ADS)

Noctilucent Clouds (NLCs) are the highest clouds in the Earth's atmosphere, residing at a mean altitude of 83 km. They have been observed since 1885 around the summer solstice and are considered to be very sensitive indicators for what is going on in the atmosphere at higher altitudes. They have been observed to both increase in brightness and frequency as well as extend to lower latitudes and it has been hypothesized that the anthropogenic causes of climatic change may be directly related to NLC presence. An experiment is currently supported through NASA's Flight Opportunities program to use a Suborbital Reusable Launch Vehicle (SRLV) to fly a manned, stabilized imager suite through an NLC layer to obtain imagery and topography data of unprecedented resolution. The campaign is targeted for July 2014 and will involve a series of flights from a high-latitude spaceport when NLC activity is observed. These data should advance our understanding of energy and momentum deposition to the upper atmosphere through enhanced observations of gravity wave perturbations, instability dynamics, and turbulent regions.

Reimuller, J. D.; Fritts, D. C.; Thomas, G. E.

2012-12-01

242

Automatic facial pattern extraction from color images using knowledge-based multistep filtering technique  

NASA Astrophysics Data System (ADS)

The paper described a technique for extracting the facial patterns from color images recorded in different imaging media. First, we extracted the skin-color pixels on the basis of statistical probability analysis of ellipsoid distributions of skin-color pixels' hue and saturation in the lightness intervals. The skin-color regions were segmented and labeled by applying the techniques of binary digital image processing. We observed 20 values of mensuration pattern variables in each region. The facial patterns were extracted from skin-color regions by evaluating their pattern variable values using the knowledge-based multistep filtering technique. This technique could extract the facial patterns from color images simply and automatically as verified by the experimental results. It is significant for operations or systems where locating and detecting the facial pattern are critical important.

Sanger, Demas S.; Haneishi, Hideaki; Miyake, Yoichi

1995-08-01

243

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

244

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

245

Polarization of Directly Imaged Young Giant Planets as a Probe of Mass, Rotation, and Clouds  

NASA Technical Reports Server (NTRS)

Young, hot gas giant planets at large separations from their primaries have been directly imaged around several nearby stars. More such planets will likely be detected by ongoing and new imaging surveys with instruments such as the Gemini Planet Imager (GPI). Efforts continue to model the spectra of these planets in order to constrain their masses, effective temperatures, composition, and cloud structure. One potential tool for analyzing these objects, which has received relatively less attention, is polarization. Linear polarization of gas giant exoplanets can arise from the combined influences of light scattering by atmospheric dust and a rotationally distorted shape. The oblateness of gas giant planet increases of course with rotation rate and for fixed rotation also rises with decreasing gravity. Thus young, lower mass gas giant planets with youthful inflated radii could easily have oblateness greater than that of Saturn s 10%. We find that polarizations of over 1% may easily be produced in the near-infrared in such cases. This magnitude of polarization may be measurable by GPI and other instruments. Thus if detected, polarization of a young Jupiter places constraints on the combination of its gravity, rotation rate, and degree of cloudiness. We will present results of our multiple scattering analysis coupled with a self-consistent dusty atmospheric models to demonstrate the range of polarizations that might be expected from resolved exoplanets and the range of parameter space that such observations may inform.

Marley, Mark Scott; Sengupta, Sujan

2012-01-01

246

Image patterned molecular delivery into live cells using gold particle coated substrates  

PubMed Central

An image-patterned molecular delivery system for mammalian cells is demonstrated by pulsed laser irradiation of gold particles immobilized on a substrate below a cell monolayer. Patterned cavitation bubble nucleation was captured using a time-resolved imaging system and molecular delivery verified by observing the uptake of a membrane-impermeable fluorescent dye, calcein. Delivery efficiency as high as 90% was observed and multiplexed, patterned dye delivery was demonstrated. PMID:20173916

Wu, Ting-Hsiang; Kalim, Sheraz; Callahan, Caitlin; Teitell, Michael A.; Chiou, Pei-Yu

2010-01-01

247

Build up of electron cloud with different bunch pattern in the presence of solenoidal field  

SciTech Connect

We have augmented the code POSINST to include solenoid fields, and used it to simulate the build up of electron cloud due to electron multipacting in the PEP-II positron ring. We find that the distribution of electrons is strongly affected by the resonances associated with the cyclotron period and bunch spacing. In addition, we discover a threshold beyond which the electron density grows exponentially until it reaches the space charge limit. The threshold does not depend on the bunch spacing but does depend on the positron bunch population.

Cai, Y.; Furman, M.A.; Pivi, M.

2004-04-01

248

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

249

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.

Duane Friend

250

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

251

Cloud Games  

NSDL National Science Digital Library

Play these two matching games from the Web Weather for Kids site to pair cloud images with their names/types! Developed by the University Corporation for Atmospheric Research, this site requires Java.

University Corporation for Atmospheric Research - Education and Outreach Programs

2010-01-01

252

Cloud Types  

NSDL National Science Digital Library

This NASA website uses Macromedia Flash Player to educate users about clouds. After a short introduction, students can learn about four levels of clouds: low, mid, high, and multi. The website describes how to determine cloud level as well. Throughout the tutorial, students can listen to the explanations while viewing informative images. Users can also choose to view the text associated with the audio. While this tutorial was created for schools participating in the S'COOL project, everyone can learn a great deal about clouds from this website.

253

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.

254

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

255

Complex Clouds  

Atmospheric Science Data Center

... View Larger Image The complex structure and beauty of polar clouds are highlighted by these images acquired by the Multi-angle ... cyclonic circulation over the Southern Indian Ocean, to the north of Enderbyland, East Antarctica. The image at left was created by ...

2013-04-16

256

Photogrammetry and photo interpretation applied to analyses of cloud cover, cloud type, and cloud motion  

NASA Technical Reports Server (NTRS)

A determination was made of the areal extent of terrain obscured by clouds and cloud shadows on a portion of an Apollo 9 photograph at the instant of exposure. This photogrammetrically determined area was then compared to the cloud coverage reported by surface weather observers at approximately the same time and location, as a check on result quality. Stereograms prepared from Apollo 9 vertical photographs, illustrating various percentages of cloud coverage, are presented to help provide a quantitative appreciation of the degradation of terrain photography by clouds and their attendant shadows. A scheme, developed for the U.S. Navy, utilizing pattern recognition techniques for determining cloud motion from sequences of satellite photographs, is summarized. Clouds, turbulence, haze, and solar altitude, four elements of our natural environment which affect aerial photographic missions, are each discussed in terms of their effects on imagery obtained by aerial photography. Data of a type useful to aerial photographic mission planners, expressing photographic ground coverage in terms of flying height above terrain and camera focal length, for a standard aerial photograph format, are provided. Two oblique orbital photographs taken during the Apollo 9 flight are shown, and photo-interpretations, discussing the cloud types imaged and certain visible geographical features, are provided.

Larsen, P. A.

1972-01-01

257

Color Treatment in Endoscopic Image Classification using Multi-scale Local Color Vector Patterns  

E-print Network

-assisted analysis with the goal of detecting tumorous lesions. To get highly detailed images a magnifying endoscopeColor Treatment in Endoscopic Image Classification using Multi-scale Local Color Vector Patterns M local texture properties within color images with the aim of automated classification of endoscopic im

Uhl, Andreas

258

7 THE IMAGE FORMATION PROCESS OF THE SHROUD OF TURIN AND ITS SIMILARITIES TO VOLCKRINGER PATTERNS  

E-print Network

A new hypothesis concerning the formation of the body image on the Shroud of Turin is postulated: i.e., that lactic acid contained in the perspiration of the man on the Shroud was responsible for causing cellulose degradation in the linen cloth. Two mechanisms are assumed in the production of the image: a direct contact process; and a molecular diffusion process, in which lactic acid diffused through short distances to the cloth. This hypothesis was reached by comparing the imprints of pressed leaves with the Shroud body image. When leaves are pressed between two sheets of paper and left undisturbed for many years, "Volckringer patterns " form. Volckringer patterns and the Shroud body image are similar in spectral reflectance characteristics, UV fluorescence characteristics, sharpness of image detail, negativity and in 3-Dimensional reconstruction using a VP-8 image analyzer. The image formation process of Volckringer patterns operate long after the object is removed or degenerated; the Shroud image could also be similar to Volckringer patterns in that it might have appeared after the passage of time. It is suggested that Volckringer pattern formation and Shroud body-image formation occurred in the same way. Over the years, many hypotheses have been proposed regarding the image formation process of the Shroud of Turin. One hypothesis is that the Shroud is a painting. Walter

John A. Desalvo

259

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

Microsoft Academic Search

Ice clouds occur quite frequently, yet so much about these clouds is unknown. In recent years, numerous investigations and field campaigns have been focused on the study of ice clouds, all with the ultimate goal of gaining a better understanding of microphysical and optical properties, as well as determining the radiative impact. Perhaps one of the most recognized instruments used

Kerry Glynne Meyer

2007-01-01

260

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

261

EFFICIENT REPRESENTATION OF LIGHTING PATTERNS FOR IMAGE-BASED RELIGHTING  

E-print Network

of a scene under different lighting conditions without prior knowledge of the object geometry and surface properties in the scene. Simply put, IBL collects images of the scene under all pos- sible lighting conditions and process these images to render an image of the scene under a new lighting condition

Chen, Tsuhan

262

EFFICIENT REPRESENTATION OF LIGHTING PATTERNS FOR IMAGE-BASED RELIGHTING  

Microsoft Academic Search

Image-based relighting (IBL) has become a popular re- search topic in both computer graphics and signal process- ing. IBL is the technique that renders images of a scene under different lighting conditions without prior knowledge of the object geometry and surface properties in the scene. Simply put, IBL collects images of the scene under all pos- sible lighting conditions and

Hyunjung Shim; Tsuhan Chen

263

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

264

Three-Dimensional Transcranial Ultrasound Imaging of Microbubble Clouds Using a Sparse Hemispherical Array  

PubMed Central

There is an increasing interest in bubble-mediated focused ultrasound (FUS) interventions in the brain. However, current technology lacks the ability to spatially monitor the interaction of the microbubbles with the applied acoustic field, something which is critical for safe clinical translation of these treatments. Passive acoustic mapping could offer a means for spatially monitoring microbubble emissions that relate to bubble activity and associated bioeffects. In this study a hemispherical receiver array was integrated within an existing transcranial therapy array to create a device capable of both delivering therapy and monitoring the process via passive imaging of bubble clouds. A 128-element receiver array was constructed and characterized for varying bubble concentrations and source spacings. Initial in vivo feasibility testing was performed. The system was found to be capable of monitoring bubble emissions down to single bubble events through an ex vivo human skull. The lateral resolution of the system was found to be between 1.25-2 mm and the axial resolution between 2-3.5 mm, comparable to the resolution of MRI-based temperature monitoring during thermal FUS treatments in the brain. The results of initial in vivo experiments show that bubble activity can be mapped starting at pressure levels below the threshold for Blood-Brain barrier disruption. This study presents a feasible solution for imaging bubble activity during cavitation-mediated FUS treatments in the brain. PMID:24658252

O'Reilly, Meaghan A.; Jones, Ryan M.; Hynynen, Kullervo

2014-01-01

265

ABrIL - Advanced Brain Imaging lab.: A cloud based computation environment for cooperative neuroimaging projects.  

PubMed

Neuroscience is an increasingly multidisciplinary and highly cooperative field where neuroimaging plays an important role. Neuroimaging rapid evolution is demanding for a growing number of computing resources and skills that need to be put in place at every lab. Typically each group tries to setup their own servers and workstations to support their neuroimaging needs, having to learn from Operating System management to specific neuroscience software tools details before any results can be obtained from each setup. This setup and learning process is replicated in every lab, even if a strong collaboration among several groups is going on. In this paper we present a new cloud service model - Brain Imaging Application as a Service (BiAaaS) - and one of its implementation - Advanced Brain Imaging Lab (ABrIL) - in the form of an ubiquitous virtual desktop remote infrastructure that offers a set of neuroimaging computational services in an interactive neuroscientist-friendly graphical user interface (GUI). This remote desktop has been used for several multi-institution cooperative projects with different neuroscience objectives that already achieved important results, such as the contribution to a high impact paper published in the January issue of the Neuroimage journal. The ABrIL system has shown its applicability in several neuroscience projects with a relatively low-cost, promoting truly collaborative actions and speeding up project results and their clinical applicability. PMID:25570014

Neves Tafula, Sergio M; Moreira da Silva, Nadia; Rozanski, Verena E; Silva Cunha, Joao Paulo

2014-08-01

266

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

267

Imaging the outward motions of clumpy dust clouds around the red supergiant Antares with VLT/VISIR  

NASA Astrophysics Data System (ADS)

Aims: We present a 0."5-resolution 17.7 ?m image of the red supergiant Antares. Our aim is to study the structure of the circumstellar envelope in detail. Methods: Antares was observed at 17.7 ?m with the VLT mid-infrared instrument VISIR. Taking advantage of the BURST mode, in which a large number of short exposure frames are taken, we obtained a diffraction-limited image with a spatial resolution of 0."5. Results: The VISIR image shows six clumpy dust clouds located at 0."8-1."8 (43-96 R? = 136-306 AU) away from the star. We also detected compact emission within a radius of 0."5 around the star. Comparison of our VISIR image taken in 2010 and the 20.8 ?m image taken in 1998 with the Keck Telescope reveals the outward motions of four dust clumps. The proper motions of these dust clumps (with respect to the central star) amount to 0."2-0."6 in 12 years. This translates into expansion velocities (projected onto the plane of the sky) of 13-40 km s-1 with an uncertainty of ± 7 km s-1. The inner compact emission seen in the 2010 VISIR image is presumably newly formed dust, because it is not detected in the image taken in 1998. If we assume that the dust is ejected in 1998, the expansion velocity is estimated to be 34 km s-1, in agreement with the velocity of the outward motions of the clumpy dust clouds. The mass of the dust clouds is estimated to be (3-6) × 10-9 M?. These values are lower by a factor of 3-7 than the amount of dust ejected in one year estimated from the (gas+dust) mass-loss rate of 2 × 10-6 M? yr-1, suggesting that the continuous mass loss is superimposed on the clumpy dust cloud ejection. Conclusions: The clumpy dust envelope detected in the 17.7 ?m diffraction-limited image is similar to the clumpy or asymmetric circumstellar environment of other red supergiants. The velocities of the dust clumps cannot be explained by a simple accelerating outflow, implying the possible random nature of the dust cloud ejection mechanism. Based on VISIR observations made with the Very Large Telescope of the European Southern Observatory. Program ID: 385.D-0120(A), 286.D-5007(A).

Ohnaka, K.

2014-08-01

268

Reduction effect of the accumulated number of ghost imaging by circulatory pattern  

NASA Astrophysics Data System (ADS)

In this paper, we present experimental results concerning the reduction effect of the accumulated number of computational ghost imaging (CGI) under different light intensities. By using circulatory illumination pattern, the CGI is possible to directly reduce the accumulated number. In addition, for improvement of the spatial resolution of CGI, the illumination pattern scale is reduced illumination to the object by applying microscopic illumination system. Thereby, the propose method can be achieved high spatial resolution imaging that permitted image of microscopic object. Moreover, the proposed method provided image of the biological cell by fluorescence signal detection. As a result, we demonstrated the potential of CGI for applying measurements field of the cell biology.

Shibuya, Kyuki; Nakae, Katsuhiro; Mizutani, Yasuhiro; Iwata, Tetsuo

2014-10-01

269

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

E-print Network

. ~ . ~ . . . , ~ ~ ~ IV CONCLUSIONS AND RECOMMENDATIONS REFERENCES . . . a ~ APPENDIX THE OBJECTIVE PROGRAM . 5 15 33 35 36 LIST OF FIGURES No. Page 1. The outer boundary of the grid system utilized and the track of Hurricane Esther, the track of the 300-mb... low center and the surface frontal positions . . . 4 2. Weight factor vs grid distance 12 3. The 0000 GMTz 18 September 1961 computed 300-mb and 1000-mb contour patterns 4. The 0000 GMTi 18 September 1961 computed 300-mb absolute vorticity...

Abbott, Graham Ellis

1963-01-01

270

Basic research planning in mathematical pattern recognition and image analysis  

NASA Technical Reports Server (NTRS)

Fundamental problems encountered while attempting to develop automated techniques for applications of remote sensing are discussed under the following categories: (1) geometric and radiometric preprocessing; (2) spatial, spectral, temporal, syntactic, and ancillary digital image representation; (3) image partitioning, proportion estimation, and error models in object scene interference; (4) parallel processing and image data structures; and (5) continuing studies in polarization; computer architectures and parallel processing; and the applicability of "expert systems" to interactive analysis.

Bryant, J.; Guseman, L. F., Jr.

1981-01-01

271

Coherent lidar imaging of dust clouds: waveform comparison with the poly-phase (P4) modulation waveform  

NASA Astrophysics Data System (ADS)

A dust or aerosol cloud represents a convenient target to examine the capabilities of range-resolved Doppler and intensity (RRDI) or inverse synthetic aperture ladar (ISAR) imaging coherent laser radar, known as coherent "lidar" for optically thin targets. The poly-phase P4 ladar waveform and its RRDI images are described and compared with previous pulse-burst, linear-FM chirp pulse-compression, pseudo-random phase modulation waveforms, and several other waveforms which have not been utilized to date. A "dust cloud" has very many independently moving point scatterers with velocities that are approximately Gaussian randomly distributed in x,y,z with standard deviations of about 10% of the mean wind + aerosol velocity. This is contrary to a hard-target where the point scatterers are rigidly attached and moving together. The dust cloud produced speckle effects for the various ladar waveforms are compared. In addition, a reference set of four corner-cube retro-reflectors within the dust cloud further illustrates the differences in the various waveform capabilities and resolution.

Youmans, Douglas G.

2008-04-01

272

The effect of non-Markovian cloud patterns on the design of a regulator for a solar-powered boiler  

NASA Astrophysics Data System (ADS)

This paper provides the regulator synthesis equations for the steam temperature regulator in a solar-powered boiler. The primary source of disturbance is produced by the motion of clouds across the field of mirrors which focus solar energy on the boilers. To permit flexibility in describing a variety of cloud conditions, the cloud model is non-Markov.

Sworder, D. D.; Zondervan, K. L.

273

Data management in pattern recognition and image processing systems  

NASA Technical Reports Server (NTRS)

Data management considerations are important to any system which handles large volumes of data or where the manipulation of data is technically sophisticated. A particular problem is the introduction of image-formatted files into the mainstream of data processing application. This report describes a comprehensive system for the manipulation of image, tabular, and graphical data sets which involve conversions between the various data types. A key characteristic is the use of image processing technology to accomplish data management tasks. Because of this, the term 'image-based information system' has been adopted.

Zobrist, A. L.; Bryant, N. A.

1976-01-01

274

Proceedings of the NASA Symposium on Mathematical Pattern Recognition and Image Analysis  

NASA Technical Reports Server (NTRS)

The application of mathematical and statistical analyses techniques to imagery obtained by remote sensors is described by Principal Investigators. Scene-to-map registration, geometric rectification, and image matching are among the pattern recognition aspects discussed.

Guseman, L. F., Jr.

1983-01-01

275

Statistical image recovery from laser speckle patterns with polarization diversity  

NASA Astrophysics Data System (ADS)

This research extends the theory and understanding of the laser speckle imaging technique. This non-traditional imaging technique may be employed to improve space situational awareness and image deep space objects from a ground-based sensor system. The use of this technique is motivated by the ability to overcome aperture size limitations and the distortion effects from Earth's atmosphere. Laser speckle imaging is a lensless, coherent method for forming two-dimensional images from their autocorrelation functions. Phase retrieval from autocorrelation data is an ill-posed problem where multiple solutions exist. This research introduces polarization diversity as a method for obtaining additional information so the structure of the object being reconstructed can be improved. Results show that in some cases the images restored using polarization diversity are superior to those reconstructed without it. This research presents statistical analysis of the observed data, two distinct image recovery algorithms, and a Cramer-Rao Lower Bound on resolution. A mathematical proof is provided to demonstrate the statistical properties of the observed, noisy autocorrelation data. The algorithms are constructed using the Expectation-Maximization approach and a polarization parameter that relates two independently observed data channels. The algorithms are validated with computer simulation and laboratory experiment. Comparison is made to an existing phase-retrieval technique. The theoretical lower bound is developed for comparing theoretical performance with and without polarization diversity. The results demonstrate the laser speckle imaging technique is improved with polarization diversity.

Dixon, Donald B.

276

An objective regional cloud mask algorithm for GOES infrared imager with regime-dependent thresholds for direct radiance assimilation  

NASA Astrophysics Data System (ADS)

A local, regime-dependent cloud mask (CM) algorithm is developed for isolating cloud-free pixels from cloudy pixels for Geostationary Operational Environmental Satellite (GOES) imager radiance assimilation using mesoscale forecast models. In this CM algorithm, thresholds for six different CM tests are determined by a one-dimensional optimization approach based on probability distribution functions of the nearby cloudy and clear-sky pixels within a 10ox10o box centered at a target pixel. It is shown that the optimized thresholds over land are in general larger and display more spatial variations than over ocean. The performance of the proposed CM algorithm is compared with Moderate Resolution Imaging Spectroradiometer (MODIS) CM for a one-week period from 19 to 23 May 2008. Based on MODIS CM results, the average Probability of Correct Typing (PCT) reaches 92.94% and 91.50% over land and ocean, respectively.

Da, Cheng

277

Image-level and group-level models for Drosophila gene expression pattern annotation  

PubMed Central

Background Drosophila melanogaster has been established as a model organism for investigating the developmental gene interactions. The spatio-temporal gene expression patterns of Drosophila melanogaster can be visualized by in situ hybridization and documented as digital images. Automated and efficient tools for analyzing these expression images will provide biological insights into the gene functions, interactions, and networks. To facilitate pattern recognition and comparison, many web-based resources have been created to conduct comparative analysis based on the body part keywords and the associated images. With the fast accumulation of images from high-throughput techniques, manual inspection of images will impose a serious impediment on the pace of biological discovery. It is thus imperative to design an automated system for efficient image annotation and comparison. Results We present a computational framework to perform anatomical keywords annotation for Drosophila gene expression images. The spatial sparse coding approach is used to represent local patches of images in comparison with the well-known bag-of-words (BoW) method. Three pooling functions including max pooling, average pooling and Sqrt (square root of mean squared statistics) pooling are employed to transform the sparse codes to image features. Based on the constructed features, we develop both an image-level scheme and a group-level scheme to tackle the key challenges in annotating Drosophila gene expression pattern images automatically. To deal with the imbalanced data distribution inherent in image annotation tasks, the undersampling method is applied together with majority vote. Results on Drosophila embryonic expression pattern images verify the efficacy of our approach. Conclusion In our experiment, the three pooling functions perform comparably well in feature dimension reduction. The undersampling with majority vote is shown to be effective in tackling the problem of imbalanced data. Moreover, combining sparse coding and image-level scheme leads to consistent performance improvement in keywords annotation. PMID:24299119

2013-01-01

278

Image projection optical system for measuring pattern electroretinograms  

NASA Astrophysics Data System (ADS)

The use of the pattern-electroretinogram (PERG) as a noninvasive diagnostic tool for the early detection of glaucoma has been supported by a number of recent studies. We have developed a unique device which uses a laser interferometer to generate a sinusoidal fringe pattern that is presented to the eye in Maxwellian view for the purpose of producing a PERG response. The projection system stimulates a large visual field and is designed to bypass the optics of the eye in order to measure the true retinal response to a temporally alternating fringe pattern. The contrast, spatial frequency, total power output, orientation, alternating temporal frequency, and field location of the fringe pattern presented to the eye can all be varied by the device. It is critical for these parameters to be variable so that optimal settings may be determined for the normal state and any deviation from it, i.e. early or preclinical glaucoma. Several interferometer designs and optical projection systems were studied in order to design a compact system which provided the desired variable pattern stimulus to the eye. This paper will present a description of the clinical research instrument and its performance with the primary emphasis on the optical system design as it relates to the fringe pattern generation and other optical parameters. Examples of its use in the study of glaucoma diagnosis will also be presented.

Starkey, Douglas E.; Taboada, John; Peters, Daniel

1994-06-01

279

Microphysical and optical properties of ice clouds derived from the Airborne Visible\\/Infrared Imaging Spectrometer measurements  

Microsoft Academic Search

In this paper, we introduce a method to simultaneously retrieve ice crystal effective size and cirrus cloud optical thickness using 1.38- and 1.88-mu m cirrus reflectance from Airborne Visible\\/Infrared Imaging Spectrometer (AVIRIS) data. Atmospheric and surface effects are removed from this data to obtain isolated cirrus reflectance. An effective size and optical thickness look-up table has been produced for each

K. Meyer; P. Yang; B. Gao; W. Wiscombe; Y. X. Hu

2004-01-01

280

Authentication of random patterns by finding a match in an image database  

Microsoft Academic Search

This paper describes an approach for finding the exact match of a random texture pattern in an image database. It is assumed that the random pattern may be misregistered relative to its representation in the database and it may have missing parts. The specific application of the proposed algorithm is authentication of legal documents, bank notes or credit cards, where

Dragana Brzakovic; Nenad Vujovic

1996-01-01

281

Assessing geoaccuracy of structure from motion point clouds from long-range image collections  

NASA Astrophysics Data System (ADS)

Automatically extracted and accurate scene structure generated from airborne platforms is a goal of many applications in the photogrammetry, remote sensing, and computer vision fields. This structure has traditionally been extracted automatically through the structure-from-motion (SfM) workflows. Although this process is very powerful, the analysis of error in accuracy can prove difficult. Our work presents a method of analyzing the georegistration error from SfM derived point clouds that have been transformed to a fixed Earth-based coordinate system. The error analysis is performed using synthetic airborne imagery which provides absolute truth for the ray-surface intersection of every pixel in every image. Three methods of georegistration are assessed; (1) using global positioning system (GPS) camera centers, (2) using pose information directly from on-board navigational instrumentation, and (3) using a recently developed method that utilizes the forward projection function and SfM-derived camera pose estimates. It was found that the georegistration derived from GPS camera centers and the direct use of pose information from on-board navigational instruments is very sensitive to noise from both the SfM process and instrumentation. The georegistration transform computed using the forward projection function and the derived pose estimates prove to be far more robust to these errors.

Nilosek, David; Walvoord, Derek J.; Salvaggio, Carl

2014-11-01

282

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

283

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

284

Patterned Resonance Plasmonic Microarrays for High-Performance SPR Imaging  

PubMed Central

We report a novel optical platform based on SPR generation and confinement inside a defined 3-dimensional microwell geometry that leads to background resonance-free SPR images. The array shows an exceptionally high signal-to-noise ratio (S/N>80) for imaging analysis and subnanometric thickness resolution. An angular sensitivity of 1 degree/0.01 RIU has been achieved and the signal to background ratio (S/B) improves to 20, one order of magnitude higher than best literature results. The design proves effective for probing supported lipid membrane arrays in real time with a thickness resolution of 0.24 nm and allows for imaging analysis of microfluidic circuits where resonant spots are separated by only one pixel (~ 7 ?m). The high image quality and unique chip geometry open up new avenues for array screening and biomicrofluidics using SPRi detection. PMID:21417424

Abbas, Abdennour; Linman, Matthew J.; Cheng, Quan

2011-01-01

285

Feature Extraction for Image Pattern Matching with Cellular Automata  

E-print Network

Botha Department of Computer Science Stellenbosch University South Africa lvzijl@sun.ac.za,lbotha@cs.sun subim- ages from a library of given images. For example, given a library of photographs, a requirement

van Zijl, Lynette

286

The airborne volcanic object imaging detector (AVOID): A new tool for airborne atmospheric remote sensing of clouds  

NASA Astrophysics Data System (ADS)

A new dual thermal imaging infrared camera system has been developed for aircraft in order to investigate water and volcanic clouds ahead. The system, AVOID, uses interference filters to discriminate clouds of water and ice from volcanic substances (silicates) by utilising the spectral features of these substances at wavelengths between 8-12 µm. Tests of the system were recently conducted in Sicily, in the vicinity of Mt Etna volcano and at Stromboli volcano, during emission of ash and SO2. The data were acquired from altitudes up to 12,000 ft, sampling from two cameras at frequencies down to 1 Hz. Corrections for the aircraft attitude were made using a very fast sampling attitude sensor, collocated with the imaging system. About 30 hours of data were acquired - over 90% of these measurements were of meteorological clouds of water droplets and ice. Using a radiative transfer model and information on the spectral refractive indices of water, ice and silicate ash, a retrieval scheme has been devised to determine the mass loading and effective particle radius of these substances and some preliminary results are presented. We have also developed a sophisticated simulation tool that allows us to model the 3D structure of clouds based on Monte Carlo radiative transfer. By utilising a narrow bandpass filter centred on 8.6 µm, AVOID can also detect SO2 gas and some illustrative examples are shown. During March 2012 the AVOID system will be mounted onto an AIRBUS A340 and flown at altitudes up to 38,000 ft. These tests will include measurements of clouds, as well as drifting volcanic ash and SO2 gas. We intend to present some of these initial results.

Prata, F.; Durant, A.; Kylling, A.

2012-04-01

287

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

288

CERES CLoud Effects  

NSDL National Science Digital Library

This computer-generated animation depicts the Clouds and the Earth's Radiant Energy System (CERES) instrument in operation. CERES measures the energy at the top of the atmosphere and estimates energy levels in the atmosphere and at the Earth's surface. Using information from very high resolution cloud-imaging instruments on the same spacecraft, CERES also will determine cloud properties, including cloud amount, altitude, thickness, and the size of the cloud particles.

1997-06-06

289

Color image segmentation considering the human sensitivity for color pattern variations  

E-print Network

Color image segmentation considering the human sensitivity for color pattern variations Kuk-Jin Yoon, In-So Kweon Robotics and Computer Vision Laboratory, Dept. of EECS, KAIST, Korea ABSTRACT Color. In this paper, we propose a novel color image segmentation algorithm in consideration of human visual

Yoon, Kuk-Jin

290

New nonuniform sampling image representation method and its application in knowledge-based active pattern recognition  

Microsoft Academic Search

The research of image representation method based on nonuniform sampling and the development of the foveated sensors are active research fields in recent years. We propose in this paper a nonuniform sampling image representation method based on an improved log-polar transform and apply it into the knowledge-based active pattern recognition. The novelty of our method lies in three aspects. First,

Fuhui Long; Nanning Zheng; Jiande Jiang

1998-01-01

291

Scanned perturbation technique for imaging electromagnetic standing wave patterns of microwave cavities  

E-print Network

Scanned perturbation technique for imaging electromagnetic standing wave patterns of microwave the electric field standing wave distributions in a microwave resonator using a scanned perturbation technique-dimensional systems with arbitrarily shaped boundaries are obtained. We use a pin perturbation to image primarily

Anlage, Steven

292

Analysis of extreme ultraviolet microscopy images of patterned nanostructures based on a  

E-print Network

April 7, 2008 A method to analyze extreme ultraviolet microscopy images of nanostructures that allowsAnalysis of extreme ultraviolet microscopy images of patterned nanostructures based that uses a 13.2 nm wavelength laser light for illumination. The object's feature size and the resolution

Rocca, Jorge J.

293

Image Intensification of X-Ray Diffraction Patterns from Protein Molecules  

Microsoft Academic Search

An image intensifier film system has been used to obtain X-ray diffraction patterns suitable for quantitative measurements of protein structure. Relevant image tube characteristics have been measured, as have the corresponding TV vidicon parameters for extension of the systems to on-line digital recording and analysis.

J. R. Milch; Geo. T. Reynolds; T. C. Minor

1975-01-01

294

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

295

Fundamental Region Based Indexing and Classification of Islamic Star Pattern Images  

Microsoft Academic Search

\\u000a In this paper, we propose a new method for the indexing and classification of Islamic Stars Pattern (ISP) images based on\\u000a rotational symmetry information. A computational model for the extraction of rotational symmetry features is proposed. This\\u000a model is based on the three following steps. First, we detect the rotation center of the ISP image, then we complete the image

Mohamed Ould Djibril; Youssef Hadi; Rachid Oulad Haj Thami

2006-01-01

296

Automatic Assessment and Reduction of Noise using Edge Pattern Analysis in Non-Linear 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; Woodell, Glenn A.; Hines, Glenn D.

2004-01-01

297

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

E-print Network

. Research has found that Aqua MODIS observes more frequent ice clouds and larger optical depths and ice water paths than does Terra MODIS. Finally, an analysis of the time series of daily optical depth values revealed that ice clouds at high latitudes...

Meyer, Kerry Glynne

2009-05-15

298

Absolute phase calculation from one composite RGB fringe pattern image by wavelet transform algorithm  

NASA Astrophysics Data System (ADS)

This paper presents an absolute phase calculation method from one composite RGB fringe pattern image by using Wavelet transform algorithm and the optimum fringe number selection. Three fringe patterns having optimum fringe numbers are projected simultaneously onto an object surface via the red, green and blue channels of a DLP (Digital Light Processing) projector. From a different viewpoint, a CCD camera captures the deformed fringe patterns with respect to the object shape to get a composite RGB image. After compensating for the crosstalk and chromatic aberration between color channels, three fringe patterns are extracted from the composite color image. Wavelet Transform algorithm is studied to calculate wrapped phase from one fringe pattern. Therefore, three wrapped maps are obtained from the three extracted fringe patterns. An absolute phase map is calculated pixel by pixel after applying the optimum three-fringe numbers selection method to the three obtained wrapped phase maps. Simulated and experimental data demonstrate the algorithm's validity of calculating the absolute phase and shape information. The proposed method can measure 3D shape information of moving objects since the system needs only one RGB fringe pattern image.

Wang, Zhaohui; Jing, Zhao; Zhang, Zonghua; Guo, Tong; Zhang, Sixiang; Hu, Xiaotang

2011-11-01

299

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

300

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

301

Staining Pattern Classification of Antinuclear Autoantibodies Based on Block Segmentation in Indirect Immunofluorescence Images  

PubMed Central

Indirect immunofluorescence based on HEp-2 cell substrate is the most commonly used staining method for antinuclear autoantibodies associated with different types of autoimmune pathologies. The aim of this paper is to design an automatic system to identify the staining patterns based on block segmentation compared to the cell segmentation most used in previous research. Various feature descriptors and classifiers are tested and compared in the classification of the staining pattern of blocks and it is found that the technique of the combination of the local binary pattern and the k-nearest neighbor algorithm achieve the best performance. Relying on the results of block pattern classification, experiments on the whole images show that classifier fusion rules are able to identify the staining patterns of the whole well (specimen image) with a total accuracy of about 94.62%. PMID:25474260

Li, Jiaqian; Tseng, Kuo-Kun; Hsieh, Zu Yi; Yang, Ching Wen; Huang, Huang-Nan

2014-01-01

302

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

303

Multispectral cloud-clearing using IASI sounding and collocated AVHRR imager measurements  

NASA Astrophysics Data System (ADS)

E. S. Maddy2, T. S. King2, H. Sun2, W. W. Wolf1, C. D. Barnet1, A. Heidinger1,Z. Cheng2, and A. Gambacorta2 1NOAA/NESDIS/Center for Satellite Applications and Research, Camp Springs, Maryland, USA 2Dell, Fairfax, Virginia, USA There are several approaches for handling the effect of clouds in the IR, the most common of which include: avoiding the clouds by screening for clear-sky footprints; directly modeling the radiative effect of the clouds using sophisticated radiative transfer and cloud microphysical models; and, estimating the clear-sky portion of an IR scene by using a number of adjacent and variably cloudy footprints coupled with an estimate of the clear-sky radiance from a forecast model or collocated satellite instrument less likely to be affected by clouds. The last approach, termed cloud-clearing, is currently used at NOAA/NESDIS for operational IASI processing. NOAA currently operationally processes 100% of IASI data from calibrated and apodized L1C spectral measurements to geophysical L2 products and distributes these products to the NOAA/Comprehensive Large Array-data Stewardship System (CLASS) (available at http://class.ngdc.noaa.gov). The current algorithm used to produce the L2 products from IASI is largely based on the AIRS science team (AST) algorithm including the fast Radiative Transfer Algorithm (RTA), fast eigenvector regression, as well as cloud-clearing and physical retrieval methodologies which rely on microwave measurements from collocated AMSU to handle the effects of clouds in the IR. We will describe future upgrades to the operational cloud-clearing algorithm being used for IASI processing within NOAA/NESDIS. Specifically, our new cloud-clearing algorithm leverages off of the MetOp-A AVHRR Clouds from AVHRR (CLAVR-x) cloud mask to provide high quality, high spatial resolution InfraRed (IR) window clear-sky scene radiance estimates required for cloud-clearing inputs and quality assurance. The direct use of AVHRR clear-sky measurements decreases limitations of the current algorithm to provide high quality clear-sky radiance estimates throughout the atmospheric column, and especially near the surface to a high degree of accuracy. In turn, this enables the IASI sounder to provide high quality and high vertical and spatial resolution soundings temperature and trace gases for the study of weather and climate processes.

Maddy, E. S.; King, T. S.; Sun, H.; Wolf, W.; Barnet, C.; Heidinger, A. K.; Cheng, Z.; Gambacorta, A.

2010-12-01

304

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

305

A comparison of performance of automatic cloud coverage assessment algorithm for Formosat-2 image using clustering-based and spatial thresholding methods  

NASA Astrophysics Data System (ADS)

Formosat-2 image is a kind of high-spatial-resolution (2 meters GSD) remote sensing satellite data, which includes one panchromatic band and four multispectral bands (Blue, Green, Red, near-infrared). An essential sector in the daily processing of received Formosat-2 image is to estimate the cloud statistic of image using Automatic Cloud Coverage Assessment (ACCA) algorithm. The information of cloud statistic of image is subsequently recorded as an important metadata for image product catalog. In this paper, we propose an ACCA method with two consecutive stages: preprocessing and post-processing analysis. For pre-processing analysis, the un-supervised K-means classification, Sobel's method, thresholding method, non-cloudy pixels reexamination, and cross-band filter method are implemented in sequence for cloud statistic determination. For post-processing analysis, Box-Counting fractal method is implemented. In other words, the cloud statistic is firstly determined via pre-processing analysis, the correctness of cloud statistic of image of different spectral band is eventually cross-examined qualitatively and quantitatively via post-processing analysis. The selection of an appropriate thresholding method is very critical to the result of ACCA method. Therefore, in this work, We firstly conduct a series of experiments of the clustering-based and spatial thresholding methods that include Otsu's, Local Entropy(LE), Joint Entropy(JE), Global Entropy(GE), and Global Relative Entropy(GRE) method, for performance comparison. The result shows that Otsu's and GE methods both perform better than others for Formosat-2 image. Additionally, our proposed ACCA method by selecting Otsu's method as the threshoding method has successfully extracted the cloudy pixels of Formosat-2 image for accurate cloud statistic estimation.

Hsu, Kuo-Hsien

2012-11-01

306

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

2015-03-01

307

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

308

Spatial uncertainty modeling of fuzzy information in images for pattern classification.  

PubMed

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

309

Classification of patterns for diffuse lung diseases in thoracic CT images by AdaBoost algorithm  

NASA Astrophysics Data System (ADS)

CT images are considered as effective for differential diagnosis of diffuse lung diseases. However, the diagnosis of diffuse lung diseases is a difficult problem for the radiologists, because they show a variety of patterns on CT images. So, our purpose is to construct a computer-aided diagnosis (CAD) system for classification of patterns for diffuse lung diseases in thoracic CT images, which gives both quantitative and objective information as a second opinion, to decrease the burdens of radiologists. In this article, we propose a CAD system based on the conventional pattern recognition framework, which consists of two sub-systems; one is feature extraction part and the other is classification part. In the feature extraction part, we adopted a Gabor filter, which can extract patterns such like local edges and segments from input textures, as a feature extraction of CT images. In the recognition part, we used a boosting method. Boosting is a kind of voting method by several classifiers to improve decision precision. We applied AdaBoost algorithm for boosting method. At first, we evaluated each boosting component classifier, and we confirmed they had not enough performances in classification of patterns for diffuse lung diseases. Next, we evaluated the performance of boosting method. As a result, by use of our system, we could improve the classification rate of patterns for diffuse lung diseases.

Kuwahara, Masayuki; Kido, Shoji; Shouno, Hayaru

2009-02-01

310

Cloud Computing for radiologists.  

PubMed

Cloud computing is a concept wherein a computer grid is created using the Internet with the sole purpose of utilizing shared resources such as computer software, hardware, on a pay-per-use model. Using Cloud computing, radiology users can efficiently manage multimodality imaging units by using the latest software and hardware without paying huge upfront costs. Cloud computing systems usually work on public, private, hybrid, or community models. Using the various components of a Cloud, such as applications, client, infrastructure, storage, services, and processing power, Cloud computing can help imaging units rapidly scale and descale operations and avoid huge spending on maintenance of costly applications and storage. Cloud computing allows flexibility in imaging. It sets free radiology from the confines of a hospital and creates a virtual mobile office. The downsides to Cloud computing involve security and privacy issues which need to be addressed to ensure the success of Cloud computing in the future. PMID:23599560

Kharat, Amit T; Safvi, Amjad; Thind, Ss; Singh, Amarjit

2012-07-01

311

Computer-aided diagnosis of splenic enlargement using wave pattern of spleen in abdominal CT images  

NASA Astrophysics Data System (ADS)

It is known that the spleen accompanied by liver cirrhosis is hypertrophied or enlarged. We have examined a wave pattern at the left boundary of spleen on the abdominal CT images having liver cirrhosis, and found that they are different from those on the images having a normal liver. It is noticed that the abdominal CT images of patient with liver cirrhosis shows strong bending in the wave pattern. In the case of normal liver, the images may also have a wave pattern, but its bends are not strong. Therefore, the total waving area of the spleen with liver cirrhosis is found to be greater than that of the spleen with a normal liver. Moreover, we found that the waves of the spleen from the image with liver cirrhosis have the higher degree of circularity compared to the normal liver case. Based on the two observations above, we propose an automatic method to diagnose splenic enlargement by using the wave pattern of the spleen in abdominal CT images. The proposed automatic method improves the diagnostic performance compared with the conventional process based on the size of spleen.

Seong, Won; Cho, June-Sik; Noh, Seung-Moo; Park, Jong Won

2006-03-01

312

Bayer patterned high dynamic range image reconstruction using adaptive weighting function  

NASA Astrophysics Data System (ADS)

It is not easy to acquire a desired high dynamic range (HDR) image directly from a camera due to the limited dynamic range of most image sensors. Therefore, generally, a post-process called HDR image reconstruction is used, which reconstructs an HDR image from a set of differently exposed images to overcome the limited dynamic range. However, conventional HDR image reconstruction methods suffer from noise factors and ghost artifacts. This is due to the fact that the input images taken with a short exposure time contain much noise in the dark regions, which contributes to increased noise in the corresponding dark regions of the reconstructed HDR image. Furthermore, since input images are acquired at different times, the images contain different motion information, which results in ghost artifacts. In this paper, we propose an HDR image reconstruction method which reduces the impact of the noise factors and prevents ghost artifacts. To reduce the influence of the noise factors, the weighting function, which determines the contribution of a certain input image to the reconstructed HDR image, is designed to adapt to the exposure time and local motions. Furthermore, the weighting function is designed to exclude ghosting regions by considering the differences of the luminance and the chrominance values between several input images. Unlike conventional methods, which generally work on a color image processed by the image processing module (IPM), the proposed method works directly on the Bayer raw image. This allows for a linear camera response function and also improves the efficiency in hardware implementation. Experimental results show that the proposed method can reconstruct high-quality Bayer patterned HDR images while being robust against ghost artifacts and noise factors.

Kang, Hee; Lee, Suk Ho; Song, Ki Sun; Kang, Moon Gi

2014-12-01

313

Combined Geometric/radiometric Point Cloud Matching for Shear Analysis  

NASA Astrophysics Data System (ADS)

In the recent past, dense image matching methods such as Semi-Global Matching (SGM) became popular for many applications. The SGM approach has been adapted to and implemented for Leica ADS line-scanner data by North West Geomatics (North West) in co-operation with Leica Geosystems; it is used in North West's production workflow. One of the advantages of ADS imagery is the calibrated color information (RGB and near infrared), extending SGM-derived point clouds to dense "image point clouds" or, more general, information clouds (info clouds). With the goal of automating the quality control of ADS data, info clouds are utilized for Shear Analysis: Three-dimensional offsets of adjacent ADS image strips are determined from a pattern of info cloud pairs in strip overlaps by point cloud matching. The presented approach integrates geometry (height) and radiometry (intensity) information; matching is based on local point-to-plane distances for all points in a given cloud. The offset is derived in a least squares adjustment by applying it to each individual distance computation equation. Using intensities in addition to heights greatly benefits the offset computation, because intensity gradients tend to occur more frequently than height gradients. They can provide or complement the required information for the derivation of planimetric offset components. The paper details the combined geometric/radiometric point cloud matching approach and verifies the results against manual measurements.

Gehrke, S.

2012-07-01

314

Attempt of UAV oblique images and MLS point clouds for 4D modelling of roadside pole-like objects  

NASA Astrophysics Data System (ADS)

The state-of-the-art remote sensing technologies, namely Unmanned Aerial Vehicle (UAV) based oblique imaging and Mobile Laser Scanning (MLS) show great potential for spatial information acquisition. This study investigated the combination of the two data sources for 4D modelling of roadside pole-like objects. The data for the analysis were collected by the Microdrone md4-200 UAV imaging system and the Sensei MLS system developed by the Finnish Geodetic Institute. Pole extraction, 3D structural parameter derivation and texture segmentation were deployed on the oblique images and point clouds, and their results were fused to yield the 4D models for one example of pole-like objects, namely lighting poles. The combination techniques proved promising.

Lin, Yi; West, Geoff

2014-11-01

315

Cloud image retrieval and characterization using ground-based dual-wavelength radar at millimeter wavelengths  

NASA Astrophysics Data System (ADS)

Characterization of the microphysical properties of non-precipitating stratus clouds including their suspended-water droplet size distribution and the cloud's liquid water content are estimated in this work. The dual wavelength ratio, DWR, and the differential extinction, DE, were computed at two millimeter frequencies, 33 GHz and 95 GHz, using UMass Cloud Profiling Radar System (CPRS) to estimate the drop size distribution. Data from radiosonde observations (Raob) is used as input in a recently calibrated model for estimation of the gaseous attenuation at Ka.-band and Liebe's model at W-band. Integrated specific humidity from a radiometer is used to constrain the radiosonde specific humidity. The radar reflectivity is corrected to take into account the effect of the wind speed, the difference of beamwidth at both frequencies and the difference in sampled range cells. Radar reflectivity and ancillary data are combined to obtain the differential extinction and the estimated cloud's liquid water density. Profiles of the processed data, such as DE, the DWR and the cloud's liquid water density are presented. Cloud's water density and radar reflectivity were used for the size distribution estimation of the suspended water droplets and the median drop diameter.

Colon-Diaz, Nivia; Cruz-Pol, Sandra L.; Sekelsky, Stephen M.

2003-04-01

316

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

317

Semi-supervised Pattern Classification of Medical Images: Application to Mild Cognitive Impairment (MCI)  

PubMed Central

Many progressive disorders are characterized by unclear or transient diagnoses for specific subgroups of patients. Commonly used supervised pattern recognition methodology may not be the most suitable approach to deriving image-based biomarkers in such cases, as it relies on the availability of categorically labeled data (e.g., patients and controls). In this paper, we explore the potential of semi-supervised pattern classification to provide image-based biomarkers in the absence of precise diagnostic information for some individuals. We employ semi-supervised support vector machines (SVM) and apply them to the problem of classifying MR brain images of patients with uncertain diagnoses. We examine patterns in serial scans of ADNI participants with mild cognitive impairment (MCI), and propose that in the absence of sufficient follow-up evaluations of individuals with MCI, semi-supervised strategy is potentially more appropriate than the fully-supervised paradigm employed up to date. PMID:21195776

Filipovych, Roman; Davatzikos, Christos

2011-01-01

318

Aberrations of self-imaged patterns with two-dimensional periodicity  

NASA Astrophysics Data System (ADS)

We develop a geometrical theory of aberration in the self-imaged patterns with two-dimensional periodicity. The patterns are considered to be a crossed-line grating or a periodic array of finite apertures. We first derive the raytracing equations for determining the optical path of a self-imaging ray. We then find the third- and fifth-order contributions to the wavefront aberration which arise from the difference between the optical paths of a self-imaging ray and of an actual ray. We also derive the expression of the ray aberration from the wavefront aberration. The ray aberration is classified into five distinct types by analogy with the cases in a refracting lens system. We show that the overall ray aberration is entirely undercorrected and the aberrated image patch is decentered from an ideal image point in the direction parallel to the direction tangent vector of a chief ray. The image evaluation technique discussed here will be useful in various applications related to self-image formation of two-dimensionally periodic patterns.

Chang, Soo

2006-06-01

319

Clinical and imaging features in different inner border-zone infarct patterns.  

PubMed

Background and purpose: The clinical and imaging features of different inner border-zone infarct patterns, corona radiata (CR) and centrum semiovale (CSO), is not quiet clear. Both are mostly reported together in previous studies. We intended to observe their clinical and imaging features. Method: We observed 83 patients-47 cases with CR infarct lesion pattern and 36 cases with CSO. The lesion patterns were determined by diffusion-weighted imaging. Basic, clinical and radiologic features were compared between the patients with CR and CSO infarct lesion patterns. Results: There was no significant difference between CR and CSO infarct patterns in terms of risk factors. However, patients with CR infarct had a higher initial National Institutes of Health Stroke Scale (NIHSS) score at admission (5.2 ± 2.3) than with CSO (3.9 ± 2.0, p = 0.009). Early clinical deterioration (OR, 2.42; 95% CI, 1.12-5.21; p = 0.024) and middle cerebral artery (MCA) stenosis (OR, 10.31; 95% CI, 3.30-32.19; p < 0.0001) were independently associated with the CR infarct lesion pattern. Partial infarct lesion shape (OR, 5.95; 95% CI, 1.40-25.33; p = 0.016) and internal carotid artery (ICA) stenosis (OR, 5.28; 95% CI, 1.92-14.51; p = 0.001) were independently correlated with the CSO infarct lesion pattern. Conclusions: Although CR and CSO infarct patterns might share common etiology and mechanisms, their clinical and imaging features are different. PMID:24802279

Wang, Yujie; Wang, Jian

2014-06-01

320

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

321

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

322

Model-based classification methods of global patterns in dermoscopic images.  

PubMed

In this paper different model-based methods of classification of global patterns in dermoscopic images are proposed. Global patterns identification is included in the pattern analysis framework, the melanoma diagnosis method most used among dermatologists. The modeling is performed in two senses: first a dermoscopic image is modeled by a finite symmetric conditional Markov model applied to L?a?b? color space and the estimated parameters of this model are treated as features. In turn, the distribution of these features are supposed that follow different models along a lesion: a Gaussian model, a Gaussian mixture model, and a bag-of-features histogram model. For each case, the classification is carried out by an image retrieval approach with different distance metrics. The main objective is to classify a whole pigmented lesion into three possible patterns: globular, homogeneous, and reticular. An extensive evaluation of the performance of each method has been carried out on an image database extracted from a public Atlas of Dermoscopy. The best classification success rate is achieved by the Gaussian mixture model-based method with a 78.44% success rate in average. In a further evaluation the multicomponent pattern is analyzed obtaining a 72.91% success rate. PMID:24770918

Sáez, Aurora; Serrano, Carmen; Acha, Begoña

2014-05-01

323

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

324

Influence of broken cloud fields on reflectance retrievals  

NASA Astrophysics Data System (ADS)

Surface solar radiation forecasting permits to predict photovoltaic plant production for a massive and safe integration of solar energy into the electric network. For short-term forecasts (intra-day), methods using images from meteorological geostationary satellites are more suitable than numerical weather prediction models. Forecast schemes consist in assessing cloud motion vectors and in extrapolating cloud patterns from a given satellite image in order to predict cloud cover state above a PV plant. Atmospheric motion vectors retrieval techniques have been studied for several decades in order to improve weather forecasts. However, solar energy forecasting requires the extraction of cloud motion vectors on a finer spatial- and time-resolution than those provided for weather forecast applications. Even if motion vector retrieval is a wide research field in image processing related topics, only block-matching techniques are operationally used for solar energy forecasts via satellite images. In this paper, we propose two motion vectors extraction methods originating from video compression techniques (correlation phase and optical flow methods). We implemented them on a 6-day dataset of Meteosat-10 satellite diurnal images. We proceeded to cloud pattern extrapolation and compared predicted cloud maps against actual ones at different time horizons from 15 minutes to 4 hours ahead. Forecast scores were compared to the state-of-the-art (block matching) method. Correlation phase methods do not outperform block-matching but their computation time is about 25 times shorter. Optical flow based method outperforms all the methods with a satisfactory time computing.

Sundberg, Robert; Richtsmeier, Steven; Adler-Golden, Steven

2014-10-01

325

Accelerated computation of hologram patterns by use of interline redundancy of 3-D object images  

NASA Astrophysics Data System (ADS)

We present a new approach for accelerated computation of hologram patterns of a three-dimensional (3-D) image by taking into account of its interline redundant data. Interline redundant data of a 3-D image are extracted with the differential pulse code modulation (DPCM) algorithm, and then the CGH patterns for these compressed line images are generated with the novel lookup table (N-LUT) technique. To confirm the feasibility of the proposed method, experiments with four kinds of 3-D test objects are carried out, and the results are comparatively discussed with the conventional methods in terms of the number of object points and the computation time. Experimental results show that the number of calculated object points and the computation time for one object point have been reduced by 73.3 and 83.9%, on the average, for four test 3-D images in the proposed method employing a top-down scanning method, compared to the conventional method.

Kim, Seung-Cheol; Choe, Woo-Young; Kim, Eun-Soo

2011-09-01

326

Sub-Wavelength Imaging of Photo-Induced Refractive Index Pattern in Chalcogenide Glass Films  

SciTech Connect

Mapping of refractive index patterns with sub-wavelength resolution is achieved using Near-field Scanning Optical Microscopy (NSOM) in reflection mode. Imaging of index pattern is performed on surface gratings photo-imprinted in As2S3 films. The NSOM is adapted with a near infrared laser which wavelength (785 nm) is chosen to be within the transparency window of the glass film therefore allowing consistent measure of reflected light. Quantitative measurements of photo-induced index changes can then be obtained from knowledge of the initial film index. Images of gratings with a period of 0.5 micron are easily collected therefore demonstrating sub-wavelength spatial resolution. The technique permits to concurrently obtain a topographic image and index image of the gratings thereby permitting to quantify the extent of photodarkening and photoexpansion simultaneously. It is shown that relief gratings tend to vanish in films aged in air for several months however the index gratings remain.

Yang, Zhiyong; Anheier, Norman C.; Qiao, Hong (Amy); Lucas, Pierre

2009-11-15

327

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

328

Automated annotation of developmental stages of Drosophila embryos in images containing spatial patterns of expression  

PubMed Central

Motivation: Drosophila melanogaster is a major model organism for investigating the function and interconnection of animal genes in the earliest stages of embryogenesis. Today, images capturing Drosophila gene expression patterns are being produced at a higher throughput than ever before. The analysis of spatial patterns of gene expression is most biologically meaningful when images from a similar time point during development are compared. Thus, the critical first step is to determine the developmental stage of an embryo. This information is also needed to observe and analyze expression changes over developmental time. Currently, developmental stages (time) of embryos in images capturing spatial expression pattern are annotated manually, which is time- and labor-intensive. Embryos are often designated into stage ranges, making the information on developmental time course. This makes downstream analyses inefficient and biological interpretations of similarities and differences in spatial expression patterns challenging, particularly when using automated tools for analyzing expression patterns of large number of images. Results: Here, we present a new computational approach to annotate developmental stage for Drosophila embryos in the gene expression images. In an analysis of 3724 images, the new approach shows high accuracy in predicting the developmental stage correctly (79%). In addition, it provides a stage score that enables one to more finely annotate each embryo so that they are divided into early and late periods of development within standard stage demarcations. Stage scores for all images containing expression patterns of the same gene enable a direct way to view expression changes over developmental time for any gene. We show that the genomewide-expression-maps generated using images from embryos in refined stages illuminate global gene activities and changes much better, and more refined stage annotations improve our ability to better interpret results when expression pattern matches are discovered between genes. Availability and implementation: The software package is available for download at: http://www.public.asu.edu/?jye02/Software/Fly-Project/. Contact: jieping.ye@asu.edu Supplementary information: Supplementary data are available at Bioinformatics online. PMID:24300439

Yuan, Lei; Pan, Cheng; Ji, Shuiwang; McCutchan, Michael; Zhou, Zhi-Hua; Newfeld, Stuart J.; Kumar, Sudhir; Ye, Jieping

2014-01-01

329

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

330

Sahara Dust Cloud  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Dust Particles Click on the image for Quicktime movie from 7/15-7/24

A continent-sized cloud of hot air and dust originating from the Sahara Desert crossed the Atlantic Ocean and headed towards Florida and the Caribbean. A Saharan Air Layer, or SAL, forms when dry air and dust rise from Africa's west coast and ride the trade winds above the Atlantic Ocean.

These dust clouds are not uncommon, especially during the months of July and August. They start when weather patterns called tropical waves pick up dust from the desert in North Africa, carry it a couple of miles into the atmosphere and drift westward.

In a sequence of images created by data acquired by the Earth-orbiting Atmospheric Infrared Sounder ranging from July 15 through July 24, we see the distribution of the cloud in the atmosphere as it swirls off of Africa and heads across the ocean to the west. Using the unique silicate spectral signatures of dust in the thermal infrared, AIRS can detect the presence of dust in the atmosphere day or night. This detection works best if there are no clouds present on top of the dust; when clouds are present, they can interfere with the signal, making it much harder to detect dust as in the case of July 24, 2005.

In the Quicktime movie, the scale at the bottom of the images shows +1 for dust definitely detected, and ranges down to -1 for no dust detected. The plots are averaged over a number of AIRS observations falling within grid boxes, and so it is possible to obtain fractional numbers. [figure removed for brevity, see original site] Total Water Vapor in the Atmosphere Around the Dust Cloud Click on the image for Quicktime movie

The dust cloud is contained within a dry adiabatic layer which originates over the Sahara Desert. This Saharan Air Layer (SAL) advances Westward over the Atlantic Ocean, overriding the cool, moist air nearer the surface. This burst of very dry air is visible in the AIRS retrieved total water vapor product as a region of depressed water vapor (brown in the images) migrating slowly Westward toward the Caribbean. The SAL phenomenon inhibits the formation of tropical cyclones and thus has given the West Indies and the East Coast of the US a respite from hurricanes.

The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

2005-01-01

331

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

332

Focussing on the future: survey results on the image capture of patterned cutaneous injuries.  

PubMed

An investigator who is involved in assessing the likelihood of physical abuse must make a decision as to whether the injury seen matches the explanation given. In some instances the pattern of these injuries can give the investigator a possible link to the cause of the injury. Photographic imaging is used to record the patterned cutaneous injuries (PCI) and to facilitate forensic interpretation. The current method of capturing PCI often results in some form of distortion that causes a change to the shape of the patterned injury. The Dermatological Patterned Injury Capture and Analysis (DePICA) research group was formed to assess current image capture methods and practices. An online survey was set up to assess the value of localised imaging protocols and training specific to imaging PCI and was made available to law enforcement professionals, forensic investigators and hospital staff. 80 participants responded to the survey. The majority of the survey participants have had training in medical or forensic photography, however 66 (83%) have not had specific training in how to photograph PCI. 41 (51%) of the participants responded that they always use a rigid scale and 34 (43%) position the camera so that it is perpendicular to the scale and injury. Comments made about the quality of images obtained and produced raises concerns about how much knowledge those initiating such images have about image relevance in criminal cases. It is evident that a clear and comprehensive guide to photographing PCIs is required to improve the quality of the photographic evidence that is collected. PMID:24794842

Evans, Sam; Baylis, Sonya; Carabott, Romina; Jones, Michael; Lawson, Zoe; Marsh, Nick; Payne-James, Jason; Ramadani, Jona; Vanezis, Peter; Kemp, Alison

2014-05-01

333

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

E-print Network

and holistic features were exploited with Linear Discriminant Analysis (LDA) and SVM for gender recognitionLearning local binary patterns for gender classification on real-world face images Caifeng Shan Philips Research, Eindhoven, The Netherlands a r t i c l e i n f o Article history: Available online 27

Kim, Tae-Kyun

334

Strategies for the Segmentation of Subcutaneous Vascular Patterns in Thermographic Images  

NASA Astrophysics Data System (ADS)

Computer-assisted segmentation of vascular patterns in thermographic images provides the clinician with graphic outlines of thermally significant subcutaneous blood vessels. Segmentation strategies compared here consist of image smoothing protocols followed by thresholding and zero-crossing edge detectors. Median prefiltering followed by the Frei-Chen algorithm gave the most reproducible results, with an execution time of 143 seconds for 256 X 256 images. The Laplacian of Gaussian operator was not suitable due to streak artifacts in the thermographic imaging system. This computerized process may be adopted in a fast paced clinical environment to aid in the diagnosis and assessment of peripheral circulatory diseases, Raynaud's Disease3, phlebitis, varicose veins, as well as diseases of the autonomic nervous system. The same methodology may be applied to enhance the appearance of abnormal breast vascular patterns, and hence serve as an adjunct to mammography in the diagnosis of breast cancer. The automatically segmented vascular patterns, which have a hand drawn appearance, may also be used as a data reduction precursor to higher level pattern analysis and classification tasks.

Chan, Eric K. Y.; Pearce, John A.

1989-05-01

335

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

336

Towards Efficient Automated Characterization of Irregular Histology Images via Transformation to Frieze-Like Patterns  

E-print Network

Towards Efficient Automated Characterization of Irregular Histology Images via Transformation to Frieze-Like Patterns ABSTRACT Histology is used in both clinical and research contexts as a highly equipment has enabled high-throughput digitization of high-resolution histology slides, the manual scoring

337

Images of the Floating World: Drainage Patterns in Thinning Soap Films  

E-print Network

Images of the Floating World: Drainage Patterns in Thinning Soap Films Submitted by S. Berg, E. A. There are, however, few controlled studies of entrainment and drainage in poly- meric soap films1,2 which thin not by gravity but by capillary and disjoining pressures. In this study, aqueous soap films

Troian, Sandra M.

338

Automatic Segmentation of Menisci in MR Images Using Pattern Recognition and Graph  

E-print Network

tool to evaluate soft tissue, tendon, ligaments and menisci in the knee. The menisci are locatedAutomatic Segmentation of Menisci in MR Images Using Pattern Recognition and Graph Cuts Fredrik is a non invasive method with no ionization and with good soft tissue contrast and constitutes an important

Lunds Universitet

339

Fast Pattern Recognition Using Gradient-Descent Search in an Image Pyramid James MacLean  

E-print Network

method is normalized grey-scale correlation (NGC), in which a target image is cor- related@cs.yorku.ca Abstract A new technique for fast pattern recognition using normal- ized grey-scale correlation (NGC, or accurately determine its location for registration purposes is a valuable tool in manufacturing. One popular

MacLean, W. James

340

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.

341

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) of the canvas weave comprising a painting's support. Our spectral-based algorithm employs a variant of short frequencies. Paint- ings made on canvas sections cut from the same canvas roll have been hypothesized to have

342

Pit Pattern Classification of Zoom-Endoscopic Colon Images using Histogram Techniques  

Microsoft Academic Search

Histogram-based techniques for an automated classification of magnifying endoscope images with respect to pit patterns of colon lesions are discussed and compared. Currently, the results only allow a support of human observation especially due to the large number of false negatives of neoplastic lesions

M. Hdfnera; Ch. Kendlbacher; W. Mann; W. TaferPl; F. Wrba; A. Gangl; A. Vecsei; A. Uhl

2006-01-01

343

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

344

IMAGE-EUV Observation of Large Scale Standing Wave Pattern in the Nightside Plasmasphere  

NASA Technical Reports Server (NTRS)

We present analyses of a nightside plasmaspheric pattern of bifurcated, filamentary He(+) 30.4-nm emission enhancements observed by IMAGE EUV between approximately 19:40-22:13 UT on 28 June 2000 that indicate the presence of a large-scale, global ULF standing wave pattern. Analysis of coincident IMAGE magnetometer chain data reveals that these ULF waves extend across the magnetic latitude-longitude range of the chain and possess multiple spectral features between 0.6-5-mHz (3-30 minute period). Additionally, analysis of ACE SWE data reveals similarly structured spectral components in the solar wind. Collectively, these analyses lead to the conclusion that the observed large-scale ULF wave pattern is the result of solar wind pressure pulses 'ringing' the inner-magnetosphere.

Six, N. Frank (Technical Monitor); Gallagher, D. L.; Adrian, M. L.; Sandel, B. R.

2002-01-01

345

Global assessment of AMSR-E and MODIS cloud liquid water path retrievals in warm oceanic clouds  

NASA Astrophysics Data System (ADS)

We compared 1 year of Advanced Microwave Scanning Radiometer-EOS (AMSR-E) Wentz and Moderate Resolution Imaging Spectroradiometer (MODIS) cloud liquid water path estimates in warm marine clouds. In broken scenes AMSR-E increasingly overestimated MODIS, and retrievals became uncorrelated as cloud fraction decreased, while in overcast scenes the techniques showed generally better agreement, but with a MODIS overestimation. We found microwave and visible near-infrared retrievals being most consistent in extensive marine Sc clouds with correlations up to 0.95 and typical RMS differences of 15 g m-2. The overall MODIS high bias in overcast domains could be removed, in a global mean sense, by adiabatic correction; however, large regional differences remained. Most notably, MODIS showed strong overestimations at high latitudes, which we traced to 3-D effects in plane-parallel visible-near-infrared retrievals over heterogeneous clouds at low Sun. In the tropics or subtropics, AMSR-E-MODIS differences also depended on cloud type, with MODIS overestimating in stratiform clouds and underestimating in cumuliform clouds, resulting in large-scale coherent bias patterns where marine Sc transitioned into trade wind Cu. We noted similar geographic variations in Wentz cloud temperature errors and MODIS 1.6-3.7 ?m droplet effective radius differences, suggesting that microwave retrieval errors due to cloud absorption uncertainties, and visible near-infrared retrieval errors due to cloud vertical stratification might have contributed to the observed liquid water path bias patterns. Finally, cloud-rain partitioning was found to introduce a systematic low bias in Wentz retrievals above 180 g m-2 as the microwave algorithm erroneously assigned an increasing portion of the liquid water content of thicker nonprecipitating clouds to rain.

Seethala, C.; HorváTh, ÁKos

2010-07-01

346

Teaching image processing and pattern recognition with the Intel OpenCV library  

NASA Astrophysics Data System (ADS)

In this paper we present an approach to teaching image processing and pattern recognition with the use of the OpenCV library. Image processing, pattern recognition and computer vision are important branches of science and apply to tasks ranging from critical, involving medical diagnostics, to everyday tasks including art and entertainment purposes. It is therefore crucial to provide students of image processing and pattern recognition with the most up-to-date solutions available. In the Institute of Electronics at the Technical University of Lodz we facilitate the teaching process in this subject with the OpenCV library, which is an open-source set of classes, functions and procedures that can be used in programming efficient and innovative algorithms for various purposes. The topics of student projects completed with the help of the OpenCV library range from automatic correction of image quality parameters or creation of panoramic images from video to pedestrian tracking in surveillance camera video sequences or head-movement-based mouse cursor control for the motorically impaired.

Koz?owski, Adam; Królak, Aleksandra

2009-06-01

347

Imaging galactic diffuse clouds: CO emission, reddening and turbulent flow in the gas around zeta Ophiuchi  

Microsoft Academic Search

Context: Most diffuse clouds are only known as kinematic features in absorption spectra, but those with appreciable H2 content may be visible in the emission of such small molecules as CH, OH, and CO. Aims: We interpret in greater detail the extensive observations of 12CO emission from diffuse gas seen around the archetypical line of sight to zeta Oph. Methods:

H. S. Liszt; J. Pety; K. Tachihara

2009-01-01

348

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

349

Automatic Procedure for the Registration of Thermographic Images with Point Clouds  

NASA Astrophysics Data System (ADS)

This paper presents a procedure for the automatic registration of thermographies with laser scanning point clouds. Given the heterogeneous nature of the two modalities, we propose a feature-based approach, satisfying the requisite that extracted features have to be invariant not only to rotation, translation and scale but also to changes in illumination and dimensionality. As speed and minimum operator interaction are prerequisites for the viability of the process in the building industry, our automatic registration procedure includes automatic feature extraction with no human intervention. With this aim, a line segment detector is used to extract 2D lines from thermographies, and 3D lines are extracted through segmentation of the point cloud. Feature-matching and the relative pose between thermographies and point cloud are obtained from an iterative procedure applied to detect and reject outliers; this includes rotation matrix and translation vector calculation and the application of the RANSAC algorithm to find a consistent set of matches. An automatically textured thermographic 3D model is the expected result of these procedures once the point cloud is filtered and triangulated.

Lagüela, S.; Armesto, J.; Arias, P.; Zakhor, A.

2012-07-01

350

Syntactic reasoning and pattern recognition for analysis of coronary artery images.  

PubMed

This paper presents a new approach to the application of structural pattern recognition methods for image understanding, based on content analysis and knowledge discovery performed on medical images. This presents in particular computer analysis and recognition of local stenoses of the coronary arteries lumen. These stenoses are the result of the appearance of arteriosclerosis plaques, which in consequence lead to different forms of ischemic cardiovascular diseases. Such diseases may be seen in the form of stable or unstable disturbances of heart rhythm or infarctions. Analysis of the correct morphology of these arteries lumen is possible with the application of the syntactic analysis and pattern recognition methods, in particular with the attributed grammar of LALR type. In the paper, we shall describe all stages of analysis and understanding of images in the context of obtained features, and we shall also present the proper algorithm of syntactic reasoning based on the acquired knowledge. PMID:12234721

Ogiela, Marek R; Tadeusiewicz, Ryszard

2002-01-01

351

Abnormal Image Detection in Endoscopy Videos Using a Filter Bank and Local Binary Patterns.  

PubMed

Finding mucosal abnormalities (e.g., erythema, blood, ulcer, erosion, and polyp) is one of the most essential tasks during endoscopy video review. Since these abnormalities typically appear in a small number of frames (around 5% of the total frame number), automated detection of frames with an abnormality can save physician's time significantly. In this paper, we propose a new multi-texture analysis method that effectively discerns images showing mucosal abnormalities from the ones without any abnormality since most abnormalities in endoscopy images have textures that are clearly distinguishable from normal textures using an advanced image texture analysis method. The method uses a "texton histogram" of an image block as features. The histogram captures the distribution of different "textons" representing various textures in an endoscopy image. The textons are representative response vectors of an application of a combination of Leung and Malik (LM) filter bank (i.e., a set of image filters) and a set of Local Binary Patterns on the image. Our experimental results indicate that the proposed method achieves 92% recall and 91.8% specificity on wireless capsule endoscopy (WCE) images and 91% recall and 90.8% specificity on colonoscopy images. PMID:25132723

Nawarathna, Ruwan; Oh, JungHwan; Muthukudage, Jayantha; Tavanapong, Wallapak; Wong, Johnny; de Groen, Piet C; Tang, Shou Jiang

2014-11-20

352

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

353

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

354

Noise-Produced Patterns in Images Constructed from Magnetic Flux Leakage Data  

E-print Network

Magnetic flux leakage measurements help identify the position, size and shape of corrosion-related defects in steel casings used to protect boreholes drilled into oil and gas reservoirs. Images constructed from magnetic flux leakage data contain patterns related to noise inherent in the method. We investigate the patterns and their scaling properties for the case of delta-correlated input noise, and consider the implications for the method's ability to resolve defects. The analytical evaluation of the noise-produced patterns is made possible by model reduction facilitated by large-scale approximation. With appropriate modification, the approach can be employed to analyze noise-produced patterns in other situations where the data of interest are not measured directly, but are related to the measured data by a complex linear transform involving integrations with respect to spatial coordinates.

Pimenova, Anastasiya V; Levesley, Jeremy; Elkington, Peter; Bacciarelli, Mark

2015-01-01

355

Ammonia Clouds on Jupiter  

NASA Technical Reports Server (NTRS)

[figure removed for brevity, see original site] Click on the image for movie of Ammonia Ice Clouds on Jupiter

In this movie, put together from false-color images taken by the New Horizons Ralph instrument as the spacecraft flew past Jupiter in early 2007, show ammonia clouds (appearing as bright blue areas) as they form and disperse over five successive Jupiter 'days.' Scientists noted how the larger cloud travels along with a small, local deep hole.

2007-01-01

356

Cloud Identification  

NSDL National Science Digital Library

In this online, interactive module, students learn about the ten common cloud types and how they are formed and how to identify different cloud types on satellite images. The module is part of an online course for grades 7-12 in satellite meteorology, which includes 10 interactive modules. The site also includes lesson plans developed by teachers and links to related resources. Each module is designed to serve as a stand-alone lesson, however, a sequential approach is recommended. Designed to challenge students through the end of 12th grade, middle school teachers and students may choose to skim or skip a few sections.

2012-08-03

357

A local-sky star recognition algorithm based on rapid triangle pattern index for ICCD images  

NASA Astrophysics Data System (ADS)

Local-sky star recognition algorithm is a process of recognizing the extracted stars in image by making use of the prior rough attitude of star sensor in celestial sphere. In order to improve the detection and response performance of star sensor working in dynamic condition, ICCD is applied to imaging stars. However, image taken by ICCD has more non-Gaussian noise and the energy of imaging star is unstable. So a local-sky star recognition algorithm using spatial triangular relationship as matching features is supposed to deal with the difficulties. In the first place, an index array is designed according to Guide Triangles, which is applied to construct Guide Triangle Index List. In the second place, a general directing range of star sensor boresight is calculated according to FOV of star sensor and the output of inertial guidance system, and then, the candidate Guide Triangles set in above region is obtained rapidly. In the third place, construct image triangle patterns by applying position and energy of the extracted stars in the image, and then match the image triangle patterns with the above candidate Guide Triangles set for two stages, until N(N>=2) groups of successfully matched triangles pairs with smallest matching deviations sum are obtained. At the last, the recognized Guide Stars have to be matched posterior referring to the principle of simulated sky image, and the recognition results of image stars are all obtained. The proposed algorithm has compact Guide Database structure, rapid local-sky guide triangles obtaining, and good recognition correction percentage, even it has worse star location precision and more false stars. The simulation tests are performed to validate the relative efficiency and adaptation of the algorithm.

Zhang, Wei; Qi, Sheng-xiang; Zhang, Rui; Yang, Lili; Sun, Ji-fu; Song, Li-quan; Tian, Jin-wen

2013-09-01

358

Saharan Dust Cloud  

Atmospheric Science Data Center

article title:  Saharan Dust Cloud Blows Westward     Full Image A huge dust cloud blown westward from the Algerian desert is now wafting over the ... dramatic sunsets and possibly a light coating of red-brown dust on vehicles from Florida to Texas. This image, captured by JPL's ...

2013-04-16

359

Pattern classification approach to segmentation of digital chest radiographs and chest CT image slices  

NASA Astrophysics Data System (ADS)

The goal of this research was to develop a segmentation method based on a pattern classification approach. The pattern classification approach consists of classifying each pixel into one of several anatomic classes on the basis of one or more feature values. In this research, three types of locally calculated features are used: gray-level based measures, local difference measures and local texture measures. A feature selection process is performed to determine which features best discriminate between the anatomic classes. Three classifiers are used: a linear discriminant function, a k-nearest neighbor approach and a neural network. Supervised techniques train each classifier to learn the characterstics of the anatomic classes. Each classifier is trained and tested using normal images. The pattern classification approach to image segmentation has shown promise for further development. Locally calculated features are important in classifying pixels, but these alone may not be sufficient. A method for incorporating spatial information into the classification decision appears to improve the results and may be necessary for reliable segmentation. This research also shows that the pattern classification approach may be applied to images from different modalities.

McNitt-Gray, Michael F.; Sayre, James W.; Huang, H. K.; Razavi, Mahmood; Aberle, Denise R.

1994-05-01

360

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

361

Toward Image-Based Three-Dimensional Reconstruction from Cubesats: Impacts of Spatial Resolution and SNR on Point Cloud Quality  

NASA Astrophysics Data System (ADS)

The adoption of cube-satellites (cubesats) by the space community has drastically lowered the cost of access to space and reduced the development lifecycle from the hundreds of millions of dollars spent on traditional decade-long programs. Rapid deployment and low cost are attractive features of cubesat-based imaging that are conducive to applications such as disaster response and monitoring. One proposed application is 3D surface modeling through a high revisit rate constellation of cubesat imagers. This work begins with the characterization of an existing design for a cubesat imager based on ground sampled distance (GSD), signal-to-noise ratio (SNR), and smear. From this characterization, an existing 3D workflow is applied to datasets that have been degraded within the regime of spatial resolutions and signal-to-noise ratios anticipated for the cubesat imager. The fidelity of resulting point clouds are assessed locally for both an urban and a natural scene. The height of a building and normals to its surfaces are calculated from the urban scene, while quarry depth estimates and rough volume estimates of a pile of rocks are produced from the natural scene. Though the reconstructed scene geometry and completeness of the scene suffer noticeably from the degraded imagery, results indicate that useful information can still be extracted using some of these techniques up to a simulated GSD of 2 meters.

Stoddard, Jordyn

362

Effect of Clouds on Optical Imaging of the Space Shuttle During the Ascent Phase: A Statistical Analysis Based on a 3D Model  

NASA Technical Reports Server (NTRS)

Clouds are highly effective in obscuring optical images of the Space Shuttle taken during its ascent by ground-based and airborne tracking cameras. Because the imagery is used for quick-look and post-flight engineering analysis, the Columbia Accident Investigation Board (CAIB) recommended the return-to-flight effort include an upgrade of the imaging system to enable it to obtain at least three useful views of the Shuttle from lift-off to at least solid rocket booster (SRB) separation (NASA 2003). The lifetimes of individual cloud elements capable of obscuring optical views of the Shuttle are typically 20 minutes or less. Therefore, accurately observing and forecasting cloud obscuration over an extended network of cameras poses an unprecedented challenge for the current state of observational and modeling techniques. In addition, even the best numerical simulations based on real observations will never reach "truth." In order to quantify the risk that clouds would obscure optical imagery of the Shuttle, a 3D model to calculate probabilistic risk was developed. The model was used to estimate the ability of a network of optical imaging cameras to obtain at least N simultaneous views of the Shuttle from lift-off to SRB separation in the presence of an idealized, randomized cloud field.

Short, David A.; Lane, Robert E., Jr.; Winters, Katherine A.; Madura, John T.

2004-01-01

363

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

364

Alignment of 3D Point Clouds to Overhead Images Ryan S. Kaminsky1  

E-print Network

, Figure 1 shows an image from the Photo Tourism paper [20] where an SfM reconstruction has been manually. Figure 1. Left: satellite image of a town square in Prague, Czech Republic. Right: manual alignment Tourism [20]. Our goal is to automate this process. While this is indeed a powerful cue, image edges

Washington at Seattle, University of

365

Multi-line spectral imaging of dense cores in the Lupus molecular cloud  

E-print Network

The molecular clouds Lupus 1, 3 and 4 were mapped with the Mopra telescope at 3 and 12 mm. Emission lines from high density molecular tracers were detected, i.e. NH$_3$ (1,1), NH$_3$ (2,2), N$_2$H$^+$ (1-0), HC$_3$N (3-2), HC$_3$N (10-9), CS (2-1), CH$_3$OH (2$_0-1_0$)A$^+$ and CH$_3$OH (2$_{-1}-1_{-1}$)E. Velocity gradients of more than 1 km s$^{-1}$ are present in Lupus 1 and 3 and multiple gas components are present in these clouds along some lines of sight. Lupus 1 is the cloud richest in high density cores, 8 cores were detected in it, 5 cores were detected in Lupus 3 and only 2 in Lupus 4. The intensity of the three species HC$_3$N, NH$_3$ and N$_2$H$^+$ changes significantly in the various cores: cores that are brighter in HC$_3$N are fainter or undetected in NH$_3$ and N$_2$H$^+$ and vice versa. We found that the column density ratios HC$_3$N/N$_2$H$^+$ and HC$_3$N/NH$_3$ change by one order of magnitude between the cores, indicating that also the chemical abundance of these species is different. The ...

Benedettini, Milena; Burton, Micheal G; Viti, Serena; Molinari, Sergio; Caselli, Paola; Testi, Leonardo

2011-01-01

366

Cloud computing for geophysical applications (Invited)  

NASA Astrophysics Data System (ADS)

Cloud computing offers a scalable on-demand resource allocation model to evolving needs in data intensive geophysical applications, where computational needs in CPU and storage can vary over time depending on modeling or field campaign. Separate, sometimes incompatible cloud platforms and services are already available from major computing vendors (Amazon AWS, Microsoft Azure, Google Apps Engine), government agencies (NASA Nebulae) and Open Source community (Eucalyptus). Multiple cloud platforms with layered virtualization patterns (hardware-platform- software-data-or-everything as a service) provide a feature-rich environment and encourage experimentation with distributed data modeling, processing and storage. However, application and especially database development in the Cloud is different from the desktop and the compute cluster. In this presentation we will review scientific cloud applications relevant to geophysical research and present our results in building software components and cloud services for a virtual geophysical data center. We will discuss in depth economy, scalability and reliability of the distributed array and image data stores, synchronous and asynchronous RESTful services to access and model georefernced data, virtual observatory services for metadata management, and data visualization for web applications in Cloud.

Zhizhin, M.; Kihn, E. A.; Mishin, D.; Medvedev, D.; Weigel, R. S.

2010-12-01

367

REGULAR ARTICLE Static and Dynamic Body Image in Bulimia Nervosa: Mental Representation of Body Dimensions and Biological Motion Patterns  

E-print Network

Objective: The aim of the present study was to find out whether in bulimia nervosa the perceptual component of a disturbed body image is restricted to the overestimation of one’s own body dimensions (static body image) or can be extended to a misperception of one’s own motion patterns (dynamic body image). Method: Participants with bulimia nervosa (n 30) and normal controls (n 55) estimated their body dimensions by means of a photo distortion technique and their walking patterns using a biological motion distortion device. Results: Not only did participants with bulimia nervosa overestimate their own body dimensions, but also they perceived their own motion patterns corresponding to a higher BMI than did controls. Static body image was correlated with shape/ weight concerns and drive for thinness, whereas dynamic body image was associated with social insecurity and body image avoidance. Conclusion: In bulimia nervosa, body image disturbances can be extended to a dynamic component. VC 2006 by Wiley

Silja Vocks; Tanja Legenbauer; Heinz Rüddel; Nikolaus F. Troje

368

Image Processing And Pattern Recognition With Applications To Marine Biological Images  

NASA Astrophysics Data System (ADS)

Erosion and dilation of images were compared with other edge detection techniques on a variety of marine organisms. Under certain conditions the erosion and dilation technique gave better results. The critical problem resolved by our approach was low contrast imaging of randomly oriented objects that displayed random variations due to appendages that frequently appearred with marine biological samples. A multicomputer system was developed to perform image processing and morphological feature extraction on large number of samples. Emphasis was given to system reliability and expandability, allowing for performance at a reduced rate when one or more computers malfunctioned. The system currently operates with seven computers but can be expanded to contain up to seventeen. Classification accuracy on zooplankton samples from New England coastal waters was approximately 92%.

Katsinis, C.; Poularikas, A. D.; Jeffries, H. P.

1984-12-01

369

Titan's South Polar Cloud  

NASA Astrophysics Data System (ADS)

Cassini/ISS cameras detected a newly formed large cloud in the south polar region of Titan on 2012-178 (June 27). Images of this cloud in the continuum filters at 889 nm (MT3) and 935 nm (CB3) clearly reveal different characteristics relative to the'detached haze' layer that extends over all south latitudes. Figure 1 shows I/F at 889 nm, where the cloud patch is observed beyond the latitude -77º and with values of the SZA higher than 90º. In this work, we analyze different MT3/CB3 images taken by ISS cameras, in order to characterize the optical properties of this cloud as well as its altitude. We first analyze images in the MT3 filter at different angles of observation in order to have some constraints on the altitude of the cloud, and subsequently the cloud optical properties are estimated by using radiative transfer simulations.

Toledo, D.; Rannou, P.; West, R. A.; Lavvas, P.; Del Genio, A. D.; Barbara, J. M.; Roy, M.; Turtle, E. P.

2014-04-01

370

Pixel length calibration using a pattern matching method for secondary-electron images  

NASA Astrophysics Data System (ADS)

We developed a calibration method using a pattern matching method for the SEM equipped with laser interferometer units at an X-Y sample stage. By comparing two images captured before and after the stage movement, an each of moving pixel number to X and Y direction were analyzed using the image processing technique. Then the pixel length was calibrated using stage position data and the pixel data. The developed calibration methods were applied to nano-particle measurements. The sample particle sizes were nominal diameter of 100 nm and 300 nm. Measurement uncertainty evaluation was done and quantitatively reliable results were obtained.

Sugawara, Kentaro; Misumi, Ichiko; Gonda, Satoshi

2013-06-01

371

Voyager 1 imaging and IRIS observations of Jovian methane absorption and thermal emission: Implications for cloud structure  

NASA Technical Reports Server (NTRS)

Images from three filters of the Voyager 1 wide angle camera are used to measure the continuum reflectivity and spectral gradient near 6000 A and the 6190 A band methane/continuum ratio for a variety of cloud features in Jupiter's atmosphere. The dark barge features in the North Equatorial Belt have anomalously strong positive continuum spectral gradients suggesting unique composition. Methane absorption is shown at unprecedented spatial scales for the Great Red Spot and its immediate environment, for a dark barge feature in the North Equatorial Belt, and for two hot spot and plume regions in the North Equatorial Belt. Methane absorption and five micrometer emission are correlated in the vicinity of the Great Red Spot but are anticorrelated in one of the plume hot spot regions. Methane absorption and simultaneous maps of five micrometer brightness temperature is quantitatively compared to realistic cloud structure models which include multiple scattering at five micrometer as well as in the visible. Variability in H2 quadrupole lines are also investigated.

West, R. A.; Kupferman, P. N.; Hart, H.

1984-01-01

372

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.

George Tselioudis

1997-01-01

373

Self-image patterns as predictors of change and outcome of trainee-led psychotherapy  

Microsoft Academic Search

This study investigated the outcome of undergraduate trainee-led psychotherapy and how different self-image patterns explain symptom change. Pre- and post-treatment data from 235 Swedish outpatients were used. Clients were assessed with Symptom Checklist-90 (SCL-90) and the Structural Analysis of Social Behavior (SASB). Outcome effect size was moderate and in line with earlier studies on trainees. Clinical significant change showed that

Inga Dennhag; Helene Ybrandt; Kerstin Armelius

2011-01-01

374

Area-efficient low power CMOS image sensor readout circuit with fixed pattern noise cancellation  

Microsoft Academic Search

A low cost of die area and power consumption CMOS image sensor readout circuit with fixed pattern noise (FPN) cancellation\\u000a is proposed. By using only one coupling capacitor and switch in the double FPN cancelling correlative double sampling (CDS),\\u000a pixel FPN is cancelled and column FPN is stored and eliminated by the sample-and-hold operation of digitally programmable\\u000a gain amplifier (DPGA).

Shibin Zhao; Suying Yao; Kaiming Nie; Jiangtao Xu

2010-01-01

375

Detection of suspected malignant patterns in three-dimensional magnetic resonance breast images.  

PubMed

In this article, a Boolean Neural Network (BNN) is used for the detection of suspected malignant regions in 3D breast magnetic resonance (MR) images. The BNN is characterized by fast learning and classification, guaranteed convergence, and simple, integer weight calculations. The BNN learning algorithm is incremental, which allows the addition and deletion of training patterns without unlearning those already learned. The incremental learning algorithm automatically reduces the training set and trains the network only with those examples estimated to be useful. The architecture is suitable for parallel hardware implementation using available Very Large Scale Integration (VLSI) technology. The BNN was trained by using a set of malignant, benign, and false-positive patterns, extracted by experts, from selected MR studies, by using an incremental learning algorithm. After training, the network was tested by means of a consistency checking test, cross validation techniques, and patterns from actual MR breast images. During the consistency test, the BNN was tested by using the same patterns used for training. The BNN classification accuracy in this case was 99.75%, proving the ability of the BNN to select useful patterns from the training set. Then, a leave one out cross-validation (LOOCV) test was done by using patterns from the training set and the classification accuracy was 90%. Next, an extended training set was created by shifting the original patterns in different directions. A cross-validation test was then performed by dividing the set of patterns into a training and a test set. Classification accuracy was compared to the nearest neighbor classifier. Results showed that the BNN achieved an average of 77% classification accuracy while requiring only 34% of the original training set. On the other hand, the nearest neighbor classifier achieved an accuracy of 57.9% while retaining the whole training set. Another test using actual MR slices different from the training set was done and results compared favorably to a radiologist's findings. Test results show the BNN's capability to detect suspected malignant regions in 3D MR images of the breast. The proposed BNN architecture can save the radiologist a great deal of time browsing MR slices searching for suspected malignancies. PMID:9608931

el-Kwae, E A; Fishman, J E; Bianchi, M J; Pattany, P M; Kabuka, M R

1998-05-01

376

Mid-Pleistocene ice drainage pattern in the Norwegian Channel imaged by 3D seismic  

NASA Astrophysics Data System (ADS)

Several investigations have shown that a huge Late Weichselian ice stream flowed along the Norwegian Channel, and deposited thick debris flow deposits at the North Sea Fan. The development of the channel is probably mainly a result of several cycles of ice stream activity during the Quaternary. A merged 3D seismic image shows a lineated relief pattern interpreted as a uniquely well-preserved footprint of a moving ice sheet. This deep Quaternary horizon corresponds to a slightly irregular reflector on top of a parallel-layered seismic sequence. Seismic tie to the Troll core 8903 south of the study area shows that the sequence comprises Early Middle Pleistocene marine sediments. The pattern of lineations, the seismic stratigraphy, as well as the chronostratigraphic investigations of the Troll core, strongly indicate that the image reflects the initial phase of an extensive Middle Pleistocene glaciation (inferred age ca 0.5 Ma), prior to the development of a massive Norwegian Channel Ice Stream. The northwesterly oriented pattern, seen in the southeastern part of the study area, demonstrates that the ice flowed into the channel mainly from the coastal zone north of Bergen. Farther west various sets of 'fan-shaped lineations' partly cross each other, showing that the 3D-image represents a certain short time window. In the northern study area the ice flow was dominantly northwards, and directed towards the area below the present shallow Måløy Plateau. There are no indications that the glaciers north of Sognefjorden affected the marine ice sheet.

Rise, L.; Olesen, O.; Rokoengen, K.; Ottesen, D.; Riis, F.

2004-12-01

377

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

378

Jupiter's High-Altitude Clouds  

NASA Technical Reports Server (NTRS)

The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of Jupiter in this image has a mottled appearance, and the scene is not as dynamic as the equatorial and south polar regions.

The intricate structures revealed in this image are exciting, but they are only part of the story. The New Horizons instruments have taken images of Jupiter at approximately 260 different wavelengths, providing essentially a three-dimensional view of Jupiter's atmosphere, since images at different wavelengths probe different altitudes. New Horizons is providing a wealth of data on this fascinating planet during this last close-up view of Jupiter until the middle of the next decade.

2007-01-01

379

Evaluation of trabecular bone patterns on dental radiographic images: influence of cortical bone  

NASA Astrophysics Data System (ADS)

For some authors trabecular bone is highly visible in intraoral radiographs. For other authors, the observed intrabony trabecular pattern is a representation of only the endosteal surface of cortical bone, not of intermedullary striae. The purpose of this preliminary study was to investigate the true anatomical structures that are visible in routine dental radiographs and classically denoted trabecular bone. This is a major point for bone texture analysis on radiographs. Computed radiography (CR) images of dog mandible section in molar region were compared with simulations calculated from high-resolution micro-CT volumes. Calculated simulations were obtained using the Mojette Transform. By digitally editing the CT volume, the simulations were separated into trabecular and cortical components into a region of interest. Different images were compared and correlated, some bone micro-architecture parameters calculated. A high correlation was found between computed radiographs and calculated simulations from micro-CT. The Mojette transform was successful to obtain high quality images. Cortical bone did not contribute to change in a major way simulated images. These first results imply that intrabony trabecular pattern observed on radiographs can not only be a representation of the cortical bone endosteal surface and that trabecular bone is highly visible in intraoral radiographs.

Amouriq, Yves; Evenou, Pierre; Arlicot, Aurore; Normand, Nicolas; Layrolle, Pierre; Weiss, Pierre; Guédon, Jean-Pierre

2010-03-01

380

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

NASA Astrophysics Data System (ADS)

Context. Images of spatially resolved astrophysical objects contain a wealth of morphological and dynamical information, and effectively extracting this information is of paramount importance for understanding the physics and evolution of these objects. The algorithms and methods currently employed for this purpose (such as Gaussian model fitting) often use simplified approaches to describe the structure of resolved objects. Aims: Automated (unsupervised) methods for structure decomposition and tracking of structural patterns are needed for this purpose to be able to treat the complexity of structure and large amounts of data involved. Methods: We developed a new wavelet-based image segmentation and evaluation (WISE) method for multiscale decomposition, segmentation, and tracking of structural patterns in astronomical images. Results: The method was tested against simulated images of relativistic jets and applied to data from long-term monitoring of parsec-scale radio jets in 3C 273 and 3C 120. Working at its coarsest resolution, WISE reproduces the previous results of a model-fitting evaluation of the structure and kinematics in these jets exceptionally well. Extending the WISE structure analysis to fine scales provides the first robust measurements of two-dimensional velocity fields in these jets and indicates that the velocity fields probably reflect the evolution of Kelvin-Helmholtz instabilities that develop in the flow.

Mertens, Florent; Lobanov, Andrei

2015-02-01

381

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

382

Ghost imaging using labyrinth-like phase modulation patterns for high-efficiency and high-security optical encryption  

NASA Astrophysics Data System (ADS)

Ghost imaging has attracted more and more current attention due to its marked physical characteristics, and many physical applications, such as sensing and optical security, have been explored. In this letter, we propose ghost imaging using labyrinth-like phase modulation patterns for optical encryption. Since only one phase-only mask should be pre-set and the labyrinth patterns occupy only few spaces, high-efficiency storage or transmission of system keys can be implemented. In addition, each labyrinth pattern (i.e., phase modulation pattern) possesses high randomness and flexibility, hence high security can be guaranteed for the proposed optical encryption.

Chen, Wen; Chen, Xudong

2015-01-01

383

Robust non-parametric probabilistic image processing for face recognition and pattern recognition  

NASA Astrophysics Data System (ADS)

Face Recognition has been a pattern recognition application of great interest. Many mathematical models have been used for face recognition and among them probabilistic methods However, up to now probabilistic methods rely heavily on the number of training data and do not fully exploit the 2-dimensional information of the images, both the training and the testing sets. In this paper's method a new 2-D robust probabilistic method of transforming the principal components of the initial image data, allowing support vector machines to efficiently capture the inference between images. This new algorithm encodes every image with the help of Robust Kernel non Parametric Estimation and in the second stage uses Support Vector Machines to classify this encoded information. Results exhibit that Non Parametric Estimation of the Probability Function of the image highlights the unique characteristics of each person making it easier for classifiers to group those instances and efficiently perform the classification of the images and thus leading to better results compared to up to date methods for face recognition.

Pavlidou, Meropi; Zioutas, George

2014-04-01

384

Patterns and signal intensity characteristics of pelvic recurrence of rectal cancer at MR imaging.  

PubMed

Magnetic resonance (MR) imaging is becoming the cross-sectional imaging modality of choice for follow-up of patients with previous rectal cancer to diagnose pelvic recurrence and plan for surgery. The authors conducted a retrospective review of MR imaging examinations performed at their institution for evaluation of local recurrence of rectal cancer in 42 patients. Twenty-six patients had undergone rectal anastomosis and 16 had undergone abdominoperineal resection. The mean interval between initial surgery and recurrence was 2.5 years. Recurrence sites were axial (involving the anastomosis) (n = 19); lateral (sidewall) (n = 6); anterior (prostate or seminal vesicle [n = 2], bladder [n = 4], ureter [n = 3], vagina or uterus [n = 5]); or posterior (presacral fascia [n = 11], sacrum [n = 2]). Other recurrence sites included the pelvic floor (n = 7), sciatic nerve (n = 2), obturator nerve (n = 1), perineum (n = 1), abdominal wall (n = 1), or adnexa (n = 1). Recurrence was confirmed at surgery or by evidence of tumor growth at follow-up imaging. Recurrence patterns, signal intensity characteristics, findings of unresectability, potential MR imaging pitfalls, and the role of MR imaging versus other modalities in evaluating recurrent rectal carcinoma are discussed. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg335115170/-/DC1. PMID:24025941

Sinaei, Mehrdad; Swallow, Carol; Milot, Laurent; Moghaddam, Parnian Ahmadi; Smith, Andrew; Atri, Mostafa

2013-01-01

385

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

386

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

NASA Astrophysics Data System (ADS)

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 from single-phase-contrast mice chest radiographs. The results show projected density variations across the lung, highlighting regions of low density corresponding to air-filled regions. Potentially, this offers a better method than conventional radiography for detecting lung diseases such as fibrosis, emphysema and cancer, though this has yet to be demonstrated. As such, the approach can assist in continuing studies of lung function utilizing propagation-based phase-contrast imaging.

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

2005-08-01

387

Method for characterizing mask defects using image reconstruction from X-ray diffraction patterns  

DOEpatents

The invention applies techniques for image reconstruction from X-ray diffraction patterns on the three-dimensional imaging of defects in EUVL multilayer films. The reconstructed image gives information about the out-of-plane position and the diffraction strength of the defect. The positional information can be used to select the correct defect repair technique. This invention enables the fabrication of defect-free (since repaired) X-ray Mo--Si multilayer mirrors. Repairing Mo--Si multilayer-film defects on mask blanks is a key for the commercial success of EUVL. It is known that particles are added to the Mo--Si multilayer film during the fabrication process. There is a large effort to reduce this contamination, but results are not sufficient, and defects continue to be a major mask yield limiter. All suggested repair strategies need to know the out-of-plane position of the defects in the multilayer.

Hau-Riege, Stefan Peter (Fremont, CA)

2007-05-01

388

Cloud Services Cloud Services  

E-print Network

of the services as well as support. These business-ready services will allow users and groups in the UniversityCloud Services Cloud Services In 2012 UCD IT Services launched an exciting new set of cloud access These optional services are available to University staff and affiliates of the University

389

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

390

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

391

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

392

Analysis of image versus position, scale and direction reveals pattern texture anisotropy  

NASA Astrophysics Data System (ADS)

Pattern heterogeneities and anisotropies often carry significant physical information. We provide a toolbox which: (i) cumulates analysis in terms of position, direction and scale; (ii) is as general as possible; (iii) is simple and fast to understand, implement, execute and exploit. It consists in dividing the image into analysis boxes at a chosen scale; in each box an ellipse (the inertia tensor) is fitted to the signal and thus determines the direction in which the signal is more present. This tensor can be averaged in position and/or be used to study the dependence with scale. This choice is formally linked with Leray transforms and anisotropic wavelet analysis. Such protocol is intutively interpreted and consistent with what the eye detects: relevant scales, local variations in space, priviledged directions. It is fast and parallelizable. Its several variants are adaptable to the user's data and needs. It is useful to statistically characterize anisotropies of 2D or 3D patterns in which individual objects are not easily distinguished, with only minimal pre-processing of the raw image, and more generally applies to data in higher dimensions. It is less sensitive to edge effects, and thus better adapted for a multiscale analysis down to small scale boxes, than pair correlation function or Fourier transform. Easy to understand and implement, it complements more sophisticated methods such as Hough transform or diffusion tensor imaging. We use it on various fracture patterns (sea ice cover, thin sections of granite, granular materials), to pinpoint the maximal anisotropy scales. The results are robust to noise and to user choices. This toolbox could turn also useful for granular materials, hard condensed matter, geophysics, thin films, statistical mechanics, characterisation of networks, fluctuating amorphous systems, inhomogeneous and disordered systems, or medical imaging, among others.

Lehoucq, Roland; Weiss, Jerome; Dubrulle, Berengere; Amon, Axelle; Le Bouil, Antoine; Crassous, Jerome; Amitrano, David; Graner, Francois

2014-12-01

393

Automatic reconstruction of 3D urban landscape by computing connected regions and assigning them an average altitude from LiDAR point cloud image  

NASA Astrophysics Data System (ADS)

The demand of 3D city modeling has been increasing in many applications such as urban planing, computer gaming with realistic city environment, car navigation system with showing 3D city map, virtual city tourism inviting future visitors to a virtual city walkthrough and others. We proposed a simple method for reconstructing a 3D urban landscape from airborne LiDAR point cloud data. The automatic reconstruction method of a 3D urban landscape was implemented by the integration of all connected regions, which were extracted and extruded from the altitude mask images. These mask images were generated from the gray scale LiDAR image by the altitude threshold ranges. In this study we demonstrated successfully in the case of Kanazawa city center scene by applying the proposed method to the airborne LiDAR point cloud data.

Kawata, Yoshiyuki; Koizumi, Kohei

2014-10-01

394

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

395

Non-Precipitating Stratus Cloud Images Retrieval and Characterization Using a Ground-Based Dual-Wavelength  

E-print Network

. INTRODUCTION Stratus clouds frequently cover much of the sky and play a key role in keeping Earth's surface including their suspended- water droplet size distribution and the cloud's liquid water content the differential extinction and the estimated cloud's liquid water density. Profiles of the processed data

Cruz-Pol, Sandra L.

396

Numerical simulations of the three-dimensional distribution of polar mesospheric clouds and comparisons with Cloud Imaging and Particle Size (CIPS) experiment and the Solar Occultation For Ice Experiment (SOFIE) observations  

NASA Astrophysics Data System (ADS)

Polar mesospheric clouds (PMC) routinely form in the cold summer mesopause region when water vapor condenses to form ice. We use a three-dimensional chemistry-climate model based on the Whole-Atmosphere Community Climate Model (WACCM) with sectional microphysics from the Community Aerosol and Radiation Model for Atmospheres (CARMA) to study the distribution and characteristics of PMCs formed by heterogeneous nucleation of water vapor onto meteoric smoke particles. We find good agreement between these simulations and cloud properties for the Northern Hemisphere in 2007 retrieved from the Solar Occultation for Ice Experiment (SOFIE) and the Cloud Imaging and Particle Size (CIPS) experiment from the Aeronomy of Ice in the Mesosphere (AIM) mission. The main discrepancy is that simulated ice number densities are less than those retrieved by SOFIE. This discrepancy may indicate an underprediction of nucleation rates in the model, the lack of small-scale gravity waves in the model, or a bias in the SOFIE results. The WACCM/CARMA simulations are not very sensitive to large changes in the barrier to heterogeneous nucleation, which suggests that large supersaturations in the model nucleate smaller meteoric smoke particles than are traditionally assumed. Our simulations are very sensitive to the temperature structure of the summer mesopause, which in the model is largely dependent upon vertically propagating gravity waves that reach the mesopause region, break, and deposit momentum. We find that cloud radiative heating is important, with heating rates of up to 8 K/d.

Bardeen, C. G.; Toon, O. B.; Jensen, E. J.; Hervig, M. E.; Randall, C. E.; Benze, S.; Marsh, D. R.; Merkel, A.

2010-05-01

397

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

398

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

399

VLA Imaging of the Intriguing HI Cloud HIJASS J1021+6842 in the M81 Group  

E-print Network

We present VLA HI 21cm observations of HIJASS J1021+6842 which has been discovered in the direction of the M81 group. Our synthesis imaging reveals that the HI is distributed over a larger angular extent and velocity range than the single dish discovery observations. Assuming that HIJASS J1021+6842 is at the distance of the M81 group, we detect 1.5 x 10^8 M_sun of HI distributed over as much as 30 kpc, i.e., substantially larger than the biggest dwarf galaxies in the same group. At the depth of our imaging, the HI appears to be confined to at least 7 clouds. Peak HI column densities are ~1.8 x 10^20 atoms cm^-2 which is well below the canonical star formation threshold of ~10^21 atoms cm^-2 and therefore consistent with the fact that no optical counterpart has as yet been identified. A gradient in velocity is observed across the extent of the detected HI; assuming that the object is gravitationally bound we derive a dynamical mass of 7 x 10^9 M_sun and a dark-to-luminous mass ratio of >10. Alternatively, a tidal origin may also result in the observed velocity gradient which would lead to a considerably lower dynamical mass. Given the above properties and the absence of evidence of a stellar population, HIJASS J1021+6842 is unique amongst the other systems in the M81 group.

F. Walter; E. Skillman; E. Brinks

2005-06-02

400

Fully automated extraction and analysis of surface Urban Heat Island patterns from moderate resolution satellite images  

NASA Astrophysics Data System (ADS)

Comparison of thermal patterns across different cities is hampered by the lack of an appropriate methodology to extract the patterns and characterize them. What is more, increased attention by the urban climate community has been expressed to assess the magnitude and dynamics of the surface Urban Heat Island effect and to identify environmental impacts of large cities and "megacities". Motivated by this need, we propose an innovative object-based image analysis procedure to extract thermal patterns for the quantitative analysis of satellite-derived land surface temperature maps. The spatial and thermal attributes associated with these objects are then calculated and used for the analyses of the intensity, the position and the spatial extent of SUHIs. The output eventually builds up and populates a database with comparable and consistent attributes, allowing comparisons between cities as well as urban climate studies. The methodology is demonstrated over the Greater Athens Area, Greece, with more than 3000 LST images acquired by MODIS over a decade being analyzed. The approach can be potentially applied to current and future (e.g. Sentinel-3) level-2 satellite-derived land surface temperature maps of 1km spatial resolution acquired over continental and coastal cities.

Keramitsoglou, I.; Kiranoudis, C. T.

2012-04-01