WorldWideScience

Sample records for spectral edge detection

  1. Canny Edge Detection in Cross-Spectral Fused Images

    Directory of Open Access Journals (Sweden)

    Patricia Suárez

    2017-02-01

    Full Text Available Considering that the images of different spectra provide an ample information that helps a lo in the process of identification and distinction of objects that have unique spectral signatures. In this paper, the use of cross-spectral images in the process of edge detection is evaluated. This study aims to assess the Canny edge detector with two variants. The first relates to the use of merged cross-spectral images and the second the inclusion of morphological filters. To ensure the quality of the data used in this study the GQM (Goal-Question- Metrics, framework, was applied to reduce noise and increase the entropy on images. The metrics obtained in the experiments confirm that the quantity and quality of the detected edges increases significantly after the inclusion of a morphological filter and a channel of near infrared spectrum in the merged images.

  2. Spatial-Spectral Approaches to Edge Detection in Hyperspectral Remote Sensing

    Science.gov (United States)

    Cox, Cary M.

    This dissertation advances geoinformation science at the intersection of hyperspectral remote sensing and edge detection methods. A relatively new phenomenology among its remote sensing peers, hyperspectral imagery (HSI) comprises only about 7% of all remote sensing research - there are five times as many radar-focused peer reviewed journal articles than hyperspectral-focused peer reviewed journal articles. Similarly, edge detection studies comprise only about 8% of image processing research, most of which is dedicated to image processing techniques most closely associated with end results, such as image classification and feature extraction. Given the centrality of edge detection to mapping, that most important of geographic functions, improving the collective understanding of hyperspectral imagery edge detection methods constitutes a research objective aligned to the heart of geoinformation sciences. Consequently, this dissertation endeavors to narrow the HSI edge detection research gap by advancing three HSI edge detection methods designed to leverage HSI's unique chemical identification capabilities in pursuit of generating accurate, high-quality edge planes. The Di Zenzo-based gradient edge detection algorithm, an innovative version of the Resmini HySPADE edge detection algorithm and a level set-based edge detection algorithm are tested against 15 traditional and non-traditional HSI datasets spanning a range of HSI data configurations, spectral resolutions, spatial resolutions, bandpasses and applications. This study empirically measures algorithm performance against Dr. John Canny's six criteria for a good edge operator: false positives, false negatives, localization, single-point response, robustness to noise and unbroken edges. The end state is a suite of spatial-spectral edge detection algorithms that produce satisfactory edge results against a range of hyperspectral data types applicable to a diverse set of earth remote sensing applications. This work

  3. Smoothing of Fused Spectral Consistent Satellite Images with TV-based Edge Detection

    DEFF Research Database (Denmark)

    Sveinsson, Johannes; Aanæs, Henrik; Benediktsson, Jon Atli

    2007-01-01

    based on satellite data. Additionally, most conventional methods are loosely connected to the image forming physics of the satellite image, giving these methods an ad hoc feel. Vesteinsson et al. [1] proposed a method of fusion of satellite images that is based on the properties of imaging physics...... in a statistically meaningful way and was called spectral consistent panshapening (SCP). In this paper we improve this framework for satellite image fusion by introducing a better image prior, via data-dependent image smoothing. The dependency is obtained via total variation edge detection method.......Several widely used methods have been proposed for fusing high resolution panchromatic data and lower resolution multi-channel data. However, many of these methods fail to maintain the spectral consistency of the fused high resolution image, which is of high importance to many of the applications...

  4. Edge Detection,

    Science.gov (United States)

    1985-09-01

    PROJECT. T ASK0 Artificial Inteligence Laboratory AREA It WORK UNIT NUMBERS V 545 Technology Square ( Cambridge, HA 02139 I I* CONTOOL1LIN@4OFFICE NAME...ARD-A1t62 62 EDGE DETECTION(U) NASSACNUSETTS INST OF TECH CAMBRIDGE 1/1 ARTIFICIAL INTELLIGENCE LAB E C HILDRETH SEP 85 AI-M-8 N99SI4-8S-C-6595...used to carry out this analysis. cce~iO a N) ’.~" D LI’BL. P p ------------ Sj. t i MASSACHUSETTS INSTITUTE OF TECHNOLOGY i ARTIFICIAL INTELLIGENCE

  5. Natural and artificial spectral edges in exoplanets

    Science.gov (United States)

    Lingam, Manasvi; Loeb, Abraham

    2017-09-01

    Technological civilizations may rely upon large-scale photovoltaic arrays to harness energy from their host star. Photovoltaic materials, such as silicon, possess distinctive spectral features, including an 'artificial edge' that is characteristically shifted in wavelength shortwards of the 'red edge' of vegetation. Future observations of reflected light from exoplanets would be able to detect both natural and artificial edges photometrically, if a significant fraction of the planet's surface is covered by vegetation or photovoltaic arrays, respectively. The stellar energy thus tapped can be utilized for terraforming activities by transferring heat and light from the day side to the night side on tidally locked exoplanets, thereby producing detectable artefacts.

  6. High Speed Edge Detection

    Science.gov (United States)

    Prokop, Norman F (Inventor)

    2016-01-01

    Analog circuits for detecting edges in pixel arrays are disclosed. A comparator may be configured to receive an all pass signal and a low pass signal for a pixel intensity in an array of pixels. A latch may be configured to receive a counter signal and a latching signal from the comparator. The comparator may be configured to send the latching signal to the latch when the all pass signal is below the low pass signal minus an offset. The latch may be configured to hold a last negative edge location when the latching signal is received from the comparator.

  7. [Road Extraction in Remote Sensing Images Based on Spectral and Edge Analysis].

    Science.gov (United States)

    Zhao, Wen-zhi; Luo, Li-qun; Guo, Zhou; Yue, Jun; Yu, Xue-ying; Liu, Hui; Wei, Jing

    2015-10-01

    Roads are typically man-made objects in urban areas. Road extraction from high-resolution images has important applications for urban planning and transportation development. However, due to the confusion of spectral characteristic, it is difficult to distinguish roads from other objects by merely using traditional classification methods that mainly depend on spectral information. Edge is an important feature for the identification of linear objects (e. g. , roads). The distribution patterns of edges vary greatly among different objects. It is crucial to merge edge statistical information into spectral ones. In this study, a new method that combines spectral information and edge statistical features has been proposed. First, edge detection is conducted by using self-adaptive mean-shift algorithm on the panchromatic band, which can greatly reduce pseudo-edges and noise effects. Then, edge statistical features are obtained from the edge statistical model, which measures the length and angle distribution of edges. Finally, by integrating the spectral and edge statistical features, SVM algorithm is used to classify the image and roads are ultimately extracted. A series of experiments are conducted and the results show that the overall accuracy of proposed method is 93% comparing with only 78% overall accuracy of the traditional. The results demonstrate that the proposed method is efficient and valuable for road extraction, especially on high-resolution images.

  8. Spectral image reconstruction using an edge preserving spatio-spectral Wiener estimation.

    Science.gov (United States)

    Urban, Philipp; Rosen, Mitchell R; Berns, Roy S

    2009-08-01

    Reconstruction of spectral images from camera responses is investigated using an edge preserving spatio-spectral Wiener estimation. A Wiener denoising filter and a spectral reconstruction Wiener filter are combined into a single spatio-spectral filter using local propagation of the noise covariance matrix. To preserve edges the local mean and covariance matrix of camera responses is estimated by bilateral weighting of neighboring pixels. We derive the edge-preserving spatio-spectral Wiener estimation by means of Bayesian inference and show that it fades into the standard Wiener reflectance estimation shifted by a constant reflectance in case of vanishing noise. Simulation experiments conducted on a six-channel camera system and on multispectral test images show the performance of the filter, especially for edge regions. A test implementation of the method is provided as a MATLAB script at the first author's website.

  9. Power spectrum weighted edge analysis for straight edge detection in images

    Science.gov (United States)

    Karvir, Hrishikesh V.; Skipper, Julie A.

    2007-04-01

    Most man-made objects provide characteristic straight line edges and, therefore, edge extraction is a commonly used target detection tool. However, noisy images often yield broken edges that lead to missed detections, and extraneous edges that may contribute to false target detections. We present a sliding-block approach for target detection using weighted power spectral analysis. In general, straight line edges appearing at a given frequency are represented as a peak in the Fourier domain at a radius corresponding to that frequency, and a direction corresponding to the orientation of the edges in the spatial domain. Knowing the edge width and spacing between the edges, a band-pass filter is designed to extract the Fourier peaks corresponding to the target edges and suppress image noise. These peaks are then detected by amplitude thresholding. The frequency band width and the subsequent spatial filter mask size are variable parameters to facilitate detection of target objects of different sizes under known imaging geometries. Many military objects, such as trucks, tanks and missile launchers, produce definite signatures with parallel lines and the algorithm proves to be ideal for detecting such objects. Moreover, shadow-casting objects generally provide sharp edges and are readily detected. The block operation procedure offers advantages of significant reduction in noise influence, improved edge detection, faster processing speed and versatility to detect diverse objects of different sizes in the image. With Scud missile launcher replicas as target objects, the method has been successfully tested on terrain board test images under different backgrounds, illumination and imaging geometries with cameras of differing spatial resolution and bit-depth.

  10. Haptic Edge Detection Through Shear

    Science.gov (United States)

    Platkiewicz, Jonathan; Lipson, Hod; Hayward, Vincent

    2016-03-01

    Most tactile sensors are based on the assumption that touch depends on measuring pressure. However, the pressure distribution at the surface of a tactile sensor cannot be acquired directly and must be inferred from the deformation field induced by the touched object in the sensor medium. Currently, there is no consensus as to which components of strain are most informative for tactile sensing. Here, we propose that shape-related tactile information is more suitably recovered from shear strain than normal strain. Based on a contact mechanics analysis, we demonstrate that the elastic behavior of a haptic probe provides a robust edge detection mechanism when shear strain is sensed. We used a jamming-based robot gripper as a tactile sensor to empirically validate that shear strain processing gives accurate edge information that is invariant to changes in pressure, as predicted by the contact mechanics study. This result has implications for the design of effective tactile sensors as well as for the understanding of the early somatosensory processing in mammals.

  11. Green's function asymptotics near the internal edges of spectra of periodic elliptic operators. Spectral edge case

    KAUST Repository

    Kuchment, Peter

    2012-06-21

    Precise asymptotics known for the Green\\'s function of the Laplace operator have found their analogs for periodic elliptic operators of the second order at and below the bottom of the spectrum. Due to the band-gap structure of the spectra of such operators, the question arises whether similar results can be obtained near or at the edges of spectral gaps. As the result of this work shows, this is possible at a spectral edge when the dimension d ≥ 3. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Green's function asymptotics near the internal edges of spectra of periodic elliptic operators. Spectral edge case

    KAUST Repository

    Kuchment, Peter; Raich, Andrew

    2012-01-01

    Precise asymptotics known for the Green's function of the Laplace operator have found their analogs for periodic elliptic operators of the second order at and below the bottom of the spectrum. Due to the band-gap structure of the spectra of such operators, the question arises whether similar results can be obtained near or at the edges of spectral gaps. As the result of this work shows, this is possible at a spectral edge when the dimension d ≥ 3. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Information theoretic analysis of canny edge detection in visual communication

    Science.gov (United States)

    Jiang, Bo; Rahman, Zia-ur

    2011-06-01

    In general edge detection evaluation, the edge detectors are examined, analyzed, and compared either visually or with a metric for specific an application. This analysis is usually independent of the characteristics of the image-gathering, transmission and display processes that do impact the quality of the acquired image and thus, the resulting edge image. We propose a new information theoretic analysis of edge detection that unites the different components of the visual communication channel and assesses edge detection algorithms in an integrated manner based on Shannon's information theory. The edge detection algorithm here is considered to achieve high performance only if the information rate from the scene to the edge approaches the maximum possible. Thus, by setting initial conditions of the visual communication system as constant, different edge detection algorithms could be evaluated. This analysis is normally limited to linear shift-invariant filters so in order to examine the Canny edge operator in our proposed system, we need to estimate its "power spectral density" (PSD). Since the Canny operator is non-linear and shift variant, we perform the estimation for a set of different system environment conditions using simulations. In our paper we will first introduce the PSD of the Canny operator for a range of system parameters. Then, using the estimated PSD, we will assess the Canny operator using information theoretic analysis. The information-theoretic metric is also used to compare the performance of the Canny operator with other edge-detection operators. This also provides a simple tool for selecting appropriate edgedetection algorithms based on system parameters, and for adjusting their parameters to maximize information throughput.

  14. IMAGE ANALYSIS BASED ON EDGE DETECTION TECHNIQUES

    Institute of Scientific and Technical Information of China (English)

    纳瑟; 刘重庆

    2002-01-01

    A method that incorporates edge detection technique, Markov Random field (MRF), watershed segmentation and merging techniques was presented for performing image segmentation and edge detection tasks. It first applies edge detection technique to obtain a Difference In Strength (DIS) map. An initial segmented result is obtained based on K-means clustering technique and the minimum distance. Then the region process is modeled by MRF to obtain an image that contains different intensity regions. The gradient values are calculated and then the watershed technique is used. DIS calculation is used for each pixel to define all the edges (weak or strong) in the image. The DIS map is obtained. This help as priority knowledge to know the possibility of the region segmentation by the next step (MRF), which gives an image that has all the edges and regions information. In MRF model,gray level l, at pixel location i, in an image X, depends on the gray levels of neighboring pixels. The segmentation results are improved by using watershed algorithm. After all pixels of the segmented regions are processed, a map of primitive region with edges is generated. The edge map is obtained using a merge process based on averaged intensity mean values. A common edge detectors that work on (MRF) segmented image are used and the results are compared. The segmentation and edge detection result is one closed boundary per actual region in the image.

  15. Edge and line detection of complicated and blurred objects

    OpenAIRE

    Haugsdal, Kari

    2010-01-01

    This report deals with edge and line detection in pictures with complicated and/or blurred objects. It explores the alternatives available, in edge detection, edge linking and object recognition. Choice of methods are the Canny edge detection and Local edge search processing combined with regional edge search processing in the form of polygon approximation.

  16. Edge detection techniques for iris recognition system

    International Nuclear Information System (INIS)

    Tania, U T; Motakabber, S M A; Ibrahimy, M I

    2013-01-01

    Nowadays security and authentication are the major parts of our daily life. Iris is one of the most reliable organ or part of human body which can be used for identification and authentication purpose. To develop an iris authentication algorithm for personal identification, this paper examines two edge detection techniques for iris recognition system. Between the Sobel and the Canny edge detection techniques, the experimental result shows that the Canny's technique has better ability to detect points in a digital image where image gray level changes even at slow rate

  17. Edge detection in landing budgerigars (Melopsittacus undulatus.

    Directory of Open Access Journals (Sweden)

    Partha Bhagavatula

    Full Text Available BACKGROUND: While considerable scientific effort has been devoted to studying how birds navigate over long distances, relatively little is known about how targets are detected, obstacles are avoided and smooth landings are orchestrated. Here we examine how visual features in the environment, such as contrasting edges, determine where a bird will land. METHODOLOGY/PRINCIPAL FINDINGS: Landing in budgerigars (Melopsittacus undulatus was investigated by training them to fly from a perch to a feeder, and video-filming their landings. The feeder was placed on a grey disc that produced a contrasting edge against a uniformly blue background. We found that the birds tended to land primarily at the edge of the disc and walk to the feeder, even though the feeder was in the middle of the disc. This suggests that the birds were using the visual contrast at the boundary of the disc to target their landings. When the grey level of the disc was varied systematically, whilst keeping the blue background constant, there was one intermediate grey level at which the budgerigar's preference for the disc boundary disappeared. The budgerigars then landed randomly all over the test surface. Even though this disc is (for humans clearly distinguishable from the blue background, it offers very little contrast against the background, in the red and green regions of the spectrum. CONCLUSIONS: We conclude that budgerigars use visual edges to target and guide landings. Calculations of photoreceptor excitation reveal that edge detection in landing budgerigars is performed by a color-blind luminance channel that sums the signals from the red and green photoreceptors, or, alternatively, receives input from the red double-cones. This finding has close parallels to vision in honeybees and primates, where edge detection and motion perception are also largely color-blind.

  18. Tensor voting for robust color edge detection

    OpenAIRE

    Moreno, Rodrigo; García, Miguel Ángel; Puig, Domenec

    2014-01-01

    The final publication is available at Springer via http://dx.doi.org/10.1007/978-94-007-7584-8_9 This chapter proposes two robust color edge detection methods based on tensor voting. The first method is a direct adaptation of the classical tensor voting to color images where tensors are initialized with either the gradient or the local color structure tensor. The second method is based on an extension of tensor voting in which the encoding and voting processes are specifically tailored to ...

  19. Photon Counting Using Edge-Detection Algorithm

    Science.gov (United States)

    Gin, Jonathan W.; Nguyen, Danh H.; Farr, William H.

    2010-01-01

    New applications such as high-datarate, photon-starved, free-space optical communications require photon counting at flux rates into gigaphoton-per-second regimes coupled with subnanosecond timing accuracy. Current single-photon detectors that are capable of handling such operating conditions are designed in an array format and produce output pulses that span multiple sample times. In order to discern one pulse from another and not to overcount the number of incoming photons, a detection algorithm must be applied to the sampled detector output pulses. As flux rates increase, the ability to implement such a detection algorithm becomes difficult within a digital processor that may reside within a field-programmable gate array (FPGA). Systems have been developed and implemented to both characterize gigahertz bandwidth single-photon detectors, as well as process photon count signals at rates into gigaphotons per second in order to implement communications links at SCPPM (serial concatenated pulse position modulation) encoded data rates exceeding 100 megabits per second with efficiencies greater than two bits per detected photon. A hardware edge-detection algorithm and corresponding signal combining and deserialization hardware were developed to meet these requirements at sample rates up to 10 GHz. The photon discriminator deserializer hardware board accepts four inputs, which allows for the ability to take inputs from a quadphoton counting detector, to support requirements for optical tracking with a reduced number of hardware components. The four inputs are hardware leading-edge detected independently. After leading-edge detection, the resultant samples are ORed together prior to deserialization. The deserialization is performed to reduce the rate at which data is passed to a digital signal processor, perhaps residing within an FPGA. The hardware implements four separate analog inputs that are connected through RF connectors. Each analog input is fed to a high-speed 1

  20. Two-Dimensional Edge Detection by Guided Mode Resonant Metasurface

    Science.gov (United States)

    Saba, Amirhossein; Tavakol, Mohammad Reza; Karimi-Khoozani, Parisa; Khavasi, Amin

    2018-05-01

    In this letter, a new approach to perform edge detection is presented using an all-dielectric CMOS-compatible metasurface. The design is based on guided-mode resonance which provides a high quality factor resonance to make the edge detection experimentally realizable. The proposed structure that is easy to fabricate, can be exploited for detection of edges in two dimensions due to its symmetry. Also, the trade-off between gain and resolution of edge detection is discussed which can be adjusted by appropriate design parameters. The proposed edge detector has also the potential to be used in ultrafast analog computing and image processing.

  1. Edge detection and texture classification by cuttlefish.

    Science.gov (United States)

    Zylinski, Sarah; Osorio, Daniel; Shohet, Adam J

    2009-12-14

    Cephalopod mollusks including octopus and cuttlefish are adept at adaptive camouflage, varying their appearance to suit the surroundings. This behavior allows unique access into the vision of a non-human species because one can ask how these animals use spatial information to control their coloration pattern. There is particular interest in factors that affect the relative levels of expression of the Mottle and the Disruptive body patterns. Broadly speaking, the Mottle is displayed on continuous patterned surfaces whereas the Disruptive is used on discrete objects such as pebbles. Recent evidence from common cuttlefish, Sepia officinalis, suggests that multiple cues are relevant, including spatial scale, contrast, and depth. We analyze the body pattern responses of juvenile cuttlefish to a range of checkerboard stimuli. Our results suggest that the choice of camouflage pattern is consistent with a simple model of how cuttlefish classify visual textures, according to whether they are Uniform or patterned, and whether the pattern includes visual edges. In particular, cuttlefish appear to detect edges by sensing the relative spatial phases of two spatial frequency components (e.g., fundamental and the third harmonic Fourier component in a square wave). We discuss the relevance of these findings to vision and camouflage in aquatic environments.

  2. Optimal Scale Edge Detection Utilizing Noise within Images

    Directory of Open Access Journals (Sweden)

    Adnan Khashman

    2003-04-01

    Full Text Available Edge detection techniques have common problems that include poor edge detection in low contrast images, speed of recognition and high computational cost. An efficient solution to the edge detection of objects in low to high contrast images is scale space analysis. However, this approach is time consuming and computationally expensive. These expenses can be marginally reduced if an optimal scale is found in scale space edge detection. This paper presents a new approach to detecting objects within images using noise within the images. The novel idea is based on selecting one optimal scale for the entire image at which scale space edge detection can be applied. The selection of an ideal scale is based on the hypothesis that "the optimal edge detection scale (ideal scale depends on the noise within an image". This paper aims at providing the experimental evidence on the relationship between the optimal scale and the noise within images.

  3. Spectral integration in binaural signal detection

    NARCIS (Netherlands)

    Breebaart, D.J.; Par, van de S.L.J.D.E.; Kohlrausch, A.G.

    1997-01-01

    For both monaural and binaural masking, the spectral content of the masker and of the signal to be detected are important stimulus properties influencing the detection process. It is generally accepted that the auditory system separates the incoming signals in several frequency bands. It is not

  4. Application and Analysis of Wavelet Transform in Image Edge Detection

    Institute of Scientific and Technical Information of China (English)

    Jianfang gao[1

    2016-01-01

    For the image processing technology, technicians have been looking for a convenient and simple detection method for a long time, especially for the innovation research on image edge detection technology. Because there are a lot of original information at the edge during image processing, thus, we can get the real image data in terms of the data acquisition. The usage of edge is often in the case of some irregular geometric objects, and we determine the contour of the image by combining with signal transmitted data. At the present stage, there are different algorithms in image edge detection, however, different types of algorithms have divergent disadvantages so It is diffi cult to detect the image changes in a reasonable range. We try to use wavelet transformation in image edge detection, making full use of the wave with the high resolution characteristics, and combining multiple images, in order to improve the accuracy of image edge detection.

  5. Edge and line oriented contour detection : State of the art

    NARCIS (Netherlands)

    Papari, Giuseppe; Petkov, Nicolai

    We present an overview of various edge and line oriented approaches to contour detection that have been proposed in the last two decades. By edge and line oriented we mean methods that do not rely on segmentation. Distinction is made between edges and contours. Contour detectors are divided in local

  6. Edge-detect interpolation for direct digital periapical images

    International Nuclear Information System (INIS)

    Song, Nam Kyu; Koh, Kwang Joon

    1998-01-01

    The purpose of this study was to aid in the use of the digital images by edge-detect interpolation for direct digital periapical images using edge-deted interpolation. This study was performed by image processing of 20 digital periapical images; pixel replication, linear non-interpolation, linear interpolation, and edge-sensitive interpolation. The obtained results were as follows ; 1. Pixel replication showed blocking artifact and serious image distortion. 2. Linear interpolation showed smoothing effect on the edge. 3. Edge-sensitive interpolation overcame the smoothing effect on the edge and showed better image.

  7. Object detection using categorised 3D edges

    DEFF Research Database (Denmark)

    Kiforenko, Lilita; Buch, Anders Glent; Bodenhagen, Leon

    2015-01-01

    is made possible by the explicit use of edge categories in the feature descriptor. We quantitatively compare our approach with the state-of-the-art template based Linemod method, which also provides an effective way of dealing with texture-less objects, tests were performed on our own object dataset. Our...... categorisation algorithm for describing objects in terms of its different edge types. Relying on edge information allow our system to deal with objects with little or no texture or surface variation. We show that edge categorisation improves matching performance due to the higher level of discrimination, which...

  8. Edge detection based on computational ghost imaging with structured illuminations

    Science.gov (United States)

    Yuan, Sheng; Xiang, Dong; Liu, Xuemei; Zhou, Xin; Bing, Pibin

    2018-03-01

    Edge detection is one of the most important tools to recognize the features of an object. In this paper, we propose an optical edge detection method based on computational ghost imaging (CGI) with structured illuminations which are generated by an interference system. The structured intensity patterns are designed to make the edge of an object be directly imaged from detected data in CGI. This edge detection method can extract the boundaries for both binary and grayscale objects in any direction at one time. We also numerically test the influence of distance deviations in the interference system on edge extraction, i.e., the tolerance of the optical edge detection system to distance deviation. Hopefully, it may provide a guideline for scholars to build an experimental system.

  9. Using new edges for anomaly detection in computer networks

    Science.gov (United States)

    Neil, Joshua Charles

    2015-05-19

    Creation of new edges in a network may be used as an indication of a potential attack on the network. Historical data of a frequency with which nodes in a network create and receive new edges may be analyzed. Baseline models of behavior among the edges in the network may be established based on the analysis of the historical data. A new edge that deviates from a respective baseline model by more than a predetermined threshold during a time window may be detected. The new edge may be flagged as potentially anomalous when the deviation from the respective baseline model is detected. Probabilities for both new and existing edges may be obtained for all edges in a path or other subgraph. The probabilities may then be combined to obtain a score for the path or other subgraph. A threshold may be obtained by calculating an empirical distribution of the scores under historical conditions.

  10. Spectral K-edge subtraction imaging of experimental non-radioactive barium uptake in bone.

    Science.gov (United States)

    Panahifar, Arash; Samadi, Nazanin; Swanston, Treena M; Chapman, L Dean; Cooper, David M L

    2016-12-01

    To evaluate the feasibility of using non-radioactive barium as a bone tracer for detection with synchrotron spectral K-edge subtraction (SKES) technique. Male rats of 1-month old (i.e., developing skeleton) and 8-month old (i.e., skeletally mature) were orally dosed with low dose of barium chloride (33mg/kg/day Ba 2+ ) for 4weeks. The fore and hind limbs were dissected for imaging in projection and computed tomography modes at 100μm and 52μm pixel sizes. The SKES method utilizes a single bent Laue monochromator to prepare a 550eV energy spectrum to encompass the K-edge of barium (37.441keV), for collecting both 'above' and 'below' the K-edge data sets in a single scan. The SKES has a very good focal size, thus limits the 'crossover' and motion artifacts. In juvenile rats, barium was mostly incorporated in the areas of high bone turnover such as at the growth plate and the trabecular surfaces, but also in the cortical bone as the animals were growing at the time of tracer administration. However, the adults incorporated approximately half the concentration and mainly in the areas where bone remodeling was predominant and occasionally in the periosteal and endosteal layers of the diaphyseal cortical bone. The presented methodology is simple to implement and provides both structural and functional information, after labeling with barium, on bone micro-architecture and thus has great potential for in vivo imaging of pre-clinical animal models of musculoskeletal diseases to better understand their mechanisms and to evaluate the efficacy of pharmaceuticals. Copyright © 2016 Associazione Italiana di Fisica Medica. Published by Elsevier Ltd. All rights reserved.

  11. Spectral dispersion and fringe detection in IOTA

    Science.gov (United States)

    Traub, W. A.; Lacasse, M. G.; Carleton, N. P.

    1990-01-01

    Pupil plane beam combination, spectral dispersion, detection, and fringe tracking are discussed for the IOTA interferometer. A new spectrometer design is presented in which the angular dispersion with respect to wavenumber is nearly constant. The dispersing element is a type of grism, a series combination of grating and prism, in which the constant parts of the dispersion add, but the slopes cancel. This grism is optimized for the display of channelled spectra. The dispersed fringes can be tracked by a matched-filter photon-counting correlator algorithm. This algorithm requires very few arithmetic operations per detected photon, making it well-suited for real-time fringe tracking. The algorithm is able to adapt to different stellar spectral types, intensity levels, and atmospheric time constants. The results of numerical experiments are reported.

  12. An improved computing method for the image edge detection

    Institute of Scientific and Technical Information of China (English)

    Gang Wang; Liang Xiao; Anzhi He

    2007-01-01

    The framework of detecting the image edge based on the sub-pixel multi-fractal measure (SPMM) is presented. The measure is defined, which gives the sub-pixel local distribution of the image gradient. The more precise singularity exponent of every pixel can be obtained by performing the SPMM analysis on the image. Using the singularity exponents and the multi-fractal spectrum of the image, the image can be segmented into a series of sets with different singularity exponents, thus the image edge can be detected automatically and easily. The simulation results show that the SPMM has higher quality factor in the image edge detection.

  13. Edge detection in digital images using Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Marjan Kuchaki Rafsanjani

    2015-11-01

    Full Text Available Ant Colony Optimization (ACO is an optimization algorithm inspired by the behavior of real ant colonies to approximate the solutions of difficult optimization problems. In this paper, ACO is introduced to tackle the image edge detection problem. The proposed approach is based on the distribution of ants on an image; ants try to find possible edges by using a state transition function. Experimental results show that the proposed method compared to standard edge detectors is less sensitive to Gaussian noise and gives finer details and thinner edges when compared to earlier ant-based approaches.

  14. Raw Tumor MRI Edge Detection using Interval Type 2 Fuzzy ...

    African Journals Online (AJOL)

    pc

    2018-03-22

    Mar 22, 2018 ... detectors are tested on images added with 0.001 white Gaussian noise and salt and ... noise removable and its effect on edge detection to various images contents. ..... Analysis and Machine Intelligence, vol. 36, no. 7, pp.

  15. Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

    KAUST Repository

    Shakir, Muhammad Zeeshan

    2014-12-01

    This paper presents a tractable mathematical framework to analyze the spectral and energy efficiency of an operator initiated deployment of the small-cells (e.g., femtocells) where the small-cell base stations are deliberately positioned around the edge of the macrocell. The considered deployment facilitates the cell-edge mobile users in terms of their coverage, spectral, and energy efficiency and is referred to as cell-on-edge (COE) configuration. The reduction in energy consumption is achieved by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral efficiency and exact expressions for the energy efficiency of the mobile users in the considered COE configuration over generalized-K fading channels. Besides the COE configuration, the derived bounds are also shown to be useful in evaluating the performance of random small-cell deployments, e.g., uniformly distributed small-cells. Simulation results are presented to demonstrate the improvements in spectral and energy efficiency of the COE configuration with respect to macro-only networks and other unplanned deployment strategies. © 2014 Elsevier B.V. All rights reserved.

  16. Spectral Target Detection using Schroedinger Eigenmaps

    Science.gov (United States)

    Dorado-Munoz, Leidy P.

    Applications of optical remote sensing processes include environmental monitoring, military monitoring, meteorology, mapping, surveillance, etc. Many of these tasks include the detection of specific objects or materials, usually few or small, which are surrounded by other materials that clutter the scene and hide the relevant information. This target detection process has been boosted lately by the use of hyperspectral imagery (HSI) since its high spectral dimension provides more detailed spectral information that is desirable in data exploitation. Typical spectral target detectors rely on statistical or geometric models to characterize the spectral variability of the data. However, in many cases these parametric models do not fit well HSI data that impacts the detection performance. On the other hand, non-linear transformation methods, mainly based on manifold learning algorithms, have shown a potential use in HSI transformation, dimensionality reduction and classification. In target detection, non-linear transformation algorithms are used as preprocessing techniques that transform the data to a more suitable lower dimensional space, where the statistical or geometric detectors are applied. One of these non-linear manifold methods is the Schroedinger Eigenmaps (SE) algorithm that has been introduced as a technique for semi-supervised classification. The core tool of the SE algorithm is the Schroedinger operator that includes a potential term that encodes prior information about the materials present in a scene, and enables the embedding to be steered in some convenient directions in order to cluster similar pixels together. A completely novel target detection methodology based on SE algorithm is proposed for the first time in this thesis. The proposed methodology does not just include the transformation of the data to a lower dimensional space but also includes the definition of a detector that capitalizes on the theory behind SE. The fact that target pixels and

  17. On the location of spectral edges in \\mathbb {Z}-periodic media

    KAUST Repository

    Exner, Pavel; Kuchment, Peter; Winn, Brian

    2010-01-01

    Periodic second-order ordinary differential operators on ℝ are known to have the edges of their spectra to occur only at the spectra of periodic and antiperiodic boundary value problems. The multi-dimensional analog of this property is false, as was shown in a 2007 paper by some of the authors of this paper. However, one sometimes encounters the claims that in the case of a single periodicity (i.e., with respect to the lattice ℤ), the 1D property still holds, and spectral edges occur at the periodic and anti-periodic spectra only. In this work, we show that even in the simplest case of quantum graphs this is not true. It is shown that this is true if the graph consists of a 1D chain of finite graphs connected by single edges, while if the connections are formed by at least two edges, the spectral edges can already occur away from the periodic and anti-periodic spectra. © 2010 IOP Publishing Ltd.

  18. On the location of spectral edges in \\mathbb {Z}-periodic media

    KAUST Repository

    Exner, Pavel

    2010-11-09

    Periodic second-order ordinary differential operators on ℝ are known to have the edges of their spectra to occur only at the spectra of periodic and antiperiodic boundary value problems. The multi-dimensional analog of this property is false, as was shown in a 2007 paper by some of the authors of this paper. However, one sometimes encounters the claims that in the case of a single periodicity (i.e., with respect to the lattice ℤ), the 1D property still holds, and spectral edges occur at the periodic and anti-periodic spectra only. In this work, we show that even in the simplest case of quantum graphs this is not true. It is shown that this is true if the graph consists of a 1D chain of finite graphs connected by single edges, while if the connections are formed by at least two edges, the spectral edges can already occur away from the periodic and anti-periodic spectra. © 2010 IOP Publishing Ltd.

  19. Improvement and implementation for Canny edge detection algorithm

    Science.gov (United States)

    Yang, Tao; Qiu, Yue-hong

    2015-07-01

    Edge detection is necessary for image segmentation and pattern recognition. In this paper, an improved Canny edge detection approach is proposed due to the defect of traditional algorithm. A modified bilateral filter with a compensation function based on pixel intensity similarity judgment was used to smooth image instead of Gaussian filter, which could preserve edge feature and remove noise effectively. In order to solve the problems of sensitivity to the noise in gradient calculating, the algorithm used 4 directions gradient templates. Finally, Otsu algorithm adaptively obtain the dual-threshold. All of the algorithm simulated with OpenCV 2.4.0 library in the environments of vs2010, and through the experimental analysis, the improved algorithm has been proved to detect edge details more effectively and with more adaptability.

  20. [Study on spectral detection of green plant target].

    Science.gov (United States)

    Deng, Wei; Zhao, Chun-jiang; He, Xiong-kui; Chen, Li-ping; Zhang, Lu-da; Wu, Guang-wei; Mueller, J; Zhai, Chang-yuan

    2010-08-01

    Weeds grow scatteredly in fields, where many insentient objects exist, for example, withered grasses, dry twig and barriers. In order to improve the precision level of spraying, it is important to study green plant detecting technology. The present paper discussed detecting method of green plant by using spectral recognizing technology, because of the real-time feature of spectral recognition. By analyzing the reflectivity difference between each of the two sides of the "red edge" of the spectrum from plants and surrounding environment, green plant discriminat index (GPDI) is defined as the value which equals the reflectivity ratio at the wavelength of 850 nm divided by the reflectivity ratio at the wavelength of 650 nm. The original spectral data of green plants and the background were measured by using the handhold FieldSpec 3 Spectroradiometer manufactured by ASD Inc. in USA. The spectral data were processed to get the reflectivity of each measured objects and to work out the GPDI thereof as well. The classification model of green plant and its background was built up using decision tree method in order to obtain the threshold of GPDI to distinguish green plants and the background. The threshold of GPDI was chosen as 5.54. The detected object was recognized as green plant when it is GPDI>GPDITH, and vice versa. Through another test, the accuracy rate was verified which was 100% by using the threshold. The authors designed and developed the green plant detector based on single chip microcomputer (SCM) "AT89S51" and photodiode "OPT101" to realize detecting green plants from the background. After passing through two optical filters, the center wavelengths of which are 650 and 850 nm respectively, the reflected light from measured targets was detected by two photodiodes and converted into electrical signals. These analog signals were then converted to digital signals via an analog-to-digital converter (ADS7813) after being amplified by a signal amplifier (OP400

  1. Human Body Image Edge Detection Based on Wavelet Transform

    Institute of Scientific and Technical Information of China (English)

    李勇; 付小莉

    2003-01-01

    Human dresses are different in thousands way.Human body image signals have big noise, a poor light and shade contrast and a narrow range of gray gradation distribution. The application of a traditional grads method or gray method to detect human body image edges can't obtain satisfactory results because of false detections and missed detections. According to tte peculiarity of human body image, dyadic wavelet transform of cubic spline is successfully applied to detect the face and profile edges of human body image and Mallat algorithm is used in the wavelet decomposition in this paper.

  2. EXOPLANETARY DETECTION BY MULTIFRACTAL SPECTRAL ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Sahil; Wettlaufer, John S. [Program in Applied Mathematics, Yale University, New Haven, CT (United States); Sordo, Fabio Del [Department of Astronomy, Yale University, New Haven, CT (United States)

    2017-01-01

    Owing to technological advances, the number of exoplanets discovered has risen dramatically in the last few years. However, when trying to observe Earth analogs, it is often difficult to test the veracity of detection. We have developed a new approach to the analysis of exoplanetary spectral observations based on temporal multifractality, which identifies timescales that characterize planetary orbital motion around the host star and those that arise from stellar features such as spots. Without fitting stellar models to spectral data, we show how the planetary signal can be robustly detected from noisy data using noise amplitude as a source of information. For observation of transiting planets, combining this method with simple geometry allows us to relate the timescales obtained to primary and secondary eclipse of the exoplanets. Making use of data obtained with ground-based and space-based observations we have tested our approach on HD 189733b. Moreover, we have investigated the use of this technique in measuring planetary orbital motion via Doppler shift detection. Finally, we have analyzed synthetic spectra obtained using the SOAP 2.0 tool, which simulates a stellar spectrum and the influence of the presence of a planet or a spot on that spectrum over one orbital period. We have demonstrated that, so long as the signal-to-noise-ratio ≥ 75, our approach reconstructs the planetary orbital period, as well as the rotation period of a spot on the stellar surface.

  3. High Precision Edge Detection Algorithm for Mechanical Parts

    Directory of Open Access Journals (Sweden)

    Duan Zhenyun

    2018-04-01

    Full Text Available High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

  4. High Precision Edge Detection Algorithm for Mechanical Parts

    Science.gov (United States)

    Duan, Zhenyun; Wang, Ning; Fu, Jingshun; Zhao, Wenhui; Duan, Boqiang; Zhao, Jungui

    2018-04-01

    High precision and high efficiency measurement is becoming an imperative requirement for a lot of mechanical parts. So in this study, a subpixel-level edge detection algorithm based on the Gaussian integral model is proposed. For this purpose, the step edge normal section line Gaussian integral model of the backlight image is constructed, combined with the point spread function and the single step model. Then gray value of discrete points on the normal section line of pixel edge is calculated by surface interpolation, and the coordinate as well as gray information affected by noise is fitted in accordance with the Gaussian integral model. Therefore, a precise location of a subpixel edge was determined by searching the mean point. Finally, a gear tooth was measured by M&M3525 gear measurement center to verify the proposed algorithm. The theoretical analysis and experimental results show that the local edge fluctuation is reduced effectively by the proposed method in comparison with the existing subpixel edge detection algorithms. The subpixel edge location accuracy and computation speed are improved. And the maximum error of gear tooth profile total deviation is 1.9 μm compared with measurement result with gear measurement center. It indicates that the method has high reliability to meet the requirement of high precision measurement.

  5. The ship edge feature detection based on high and low threshold for remote sensing image

    Science.gov (United States)

    Li, Xuan; Li, Shengyang

    2018-05-01

    In this paper, a method based on high and low threshold is proposed to detect the ship edge feature due to the low accuracy rate caused by the noise. Analyze the relationship between human vision system and the target features, and to determine the ship target by detecting the edge feature. Firstly, using the second-order differential method to enhance the quality of image; Secondly, to improvement the edge operator, we introduction of high and low threshold contrast to enhancement image edge and non-edge points, and the edge as the foreground image, non-edge as a background image using image segmentation to achieve edge detection, and remove the false edges; Finally, the edge features are described based on the result of edge features detection, and determine the ship target. The experimental results show that the proposed method can effectively reduce the number of false edges in edge detection, and has the high accuracy of remote sensing ship edge detection.

  6. Overlapping communities detection based on spectral analysis of line graphs

    Science.gov (United States)

    Gui, Chun; Zhang, Ruisheng; Hu, Rongjing; Huang, Guoming; Wei, Jiaxuan

    2018-05-01

    Community in networks are often overlapping where one vertex belongs to several clusters. Meanwhile, many networks show hierarchical structure such that community is recursively grouped into hierarchical organization. In order to obtain overlapping communities from a global hierarchy of vertices, a new algorithm (named SAoLG) is proposed to build the hierarchical organization along with detecting the overlap of community structure. SAoLG applies the spectral analysis into line graphs to unify the overlap and hierarchical structure of the communities. In order to avoid the limitation of absolute distance such as Euclidean distance, SAoLG employs Angular distance to compute the similarity between vertices. Furthermore, we make a micro-improvement partition density to evaluate the quality of community structure and use it to obtain the more reasonable and sensible community numbers. The proposed SAoLG algorithm achieves a balance between overlap and hierarchy by applying spectral analysis to edge community detection. The experimental results on one standard network and six real-world networks show that the SAoLG algorithm achieves higher modularity and reasonable community number values than those generated by Ahn's algorithm, the classical CPM and GN ones.

  7. Behaviour of spectral entropy, spectral edge frequency 90%, and alpha and beta power parameters during low-dose propofol infusion.

    LENUS (Irish Health Repository)

    Mahon, P

    2012-02-03

    BACKGROUND: In this study we analyse the behaviour, potential clinical application and optimal cortical sampling location of the spectral parameters: (i) relative alpha and beta power; (ii) spectral edge frequency 90%; and (iii) spectral entropy as monitors of moderate propofol-induced sedation. METHODS: Multi-channel EEG recorded from 12 ASA 1 (American Society of Anesthesiologists physical status 1) patients during low-dose, target effect-site controlled propofol infusion was used for this analysis. The initial target effect-site concentration was 0.5 microg ml(-1) and increased at 4 min intervals in increments of 0.5 to 2 microg ml(-1). EEG parameters were calculated for 2 s epochs in the frequency ranges 0.5-32 and 0.5-47 Hz. All parameters were calculated in the channels: P4-O2, P3-O1, F4-C4, F3-C3, F3-F4, and Fp1-Fp2. Sedation was assessed clinically using the OAA\\/S (observer\\'s assessment of alertness\\/sedation) scale. RESULTS: Relative beta power and spectral entropy increased with increasing propofol effect-site concentration in both the 0.5-47 Hz [F(18, 90) = 3.455, P<0.05 and F(18, 90) = 3.33, P<0.05, respectively] and 0.5-32 Hz frequency range. This effect was significant in each individual channel (P<0.05). No effect was seen of increasing effect-site concentration on relative power in the alpha band. Averaged across all channels, spectral entropy did not outperform relative beta power in either the 0.5-32 Hz [Pk=0.79 vs 0.814 (P>0.05)] or 0.5-47 Hz range [Pk=0.81 vs 0.82 (P>0.05)]. The best performing indicator in any single channel was spectral entropy in the frequency range 0.5-47 Hz in the frontal channel F3-F4 (Pk=0.85). CONCLUSIONS: Relative beta power and spectral entropy when considered over the propofol effect-site range studied here increase in value, and correlate well with clinical assessment of sedation.

  8. Information theoretic analysis of edge detection in visual communication

    Science.gov (United States)

    Jiang, Bo; Rahman, Zia-ur

    2010-08-01

    Generally, the designs of digital image processing algorithms and image gathering devices remain separate. Consequently, the performance of digital image processing algorithms is evaluated without taking into account the artifacts introduced into the process by the image gathering process. However, experiments show that the image gathering process profoundly impacts the performance of digital image processing and the quality of the resulting images. Huck et al. proposed one definitive theoretic analysis of visual communication channels, where the different parts, such as image gathering, processing, and display, are assessed in an integrated manner using Shannon's information theory. In this paper, we perform an end-to-end information theory based system analysis to assess edge detection methods. We evaluate the performance of the different algorithms as a function of the characteristics of the scene, and the parameters, such as sampling, additive noise etc., that define the image gathering system. The edge detection algorithm is regarded to have high performance only if the information rate from the scene to the edge approaches the maximum possible. This goal can be achieved only by jointly optimizing all processes. People generally use subjective judgment to compare different edge detection methods. There is not a common tool that can be used to evaluate the performance of the different algorithms, and to give people a guide for selecting the best algorithm for a given system or scene. Our information-theoretic assessment becomes this new tool to which allows us to compare the different edge detection operators in a common environment.

  9. Detecting a many-body mobility edge with quantum quenches

    Directory of Open Access Journals (Sweden)

    Piero Naldesi, Elisa Ercolessi, Tommaso Roscilde

    2016-10-01

    Full Text Available The many-body localization (MBL transition is a quantum phase transition involving highly excited eigenstates of a disordered quantum many-body Hamiltonian, which evolve from "extended/ergodic" (exhibiting extensive entanglement entropies and fluctuations to "localized" (exhibiting area-law scaling of entanglement and fluctuations. The MBL transition can be driven by the strength of disorder in a given spectral range, or by the energy density at fixed disorder - if the system possesses a many-body mobility edge. Here we propose to explore the latter mechanism by using "quantum-quench spectroscopy", namely via quantum quenches of variable width which prepare the state of the system in a superposition of eigenstates of the Hamiltonian within a controllable spectral region. Studying numerically a chain of interacting spinless fermions in a quasi-periodic potential, we argue that this system has a many-body mobility edge; and we show that its existence translates into a clear dynamical transition in the time evolution immediately following a quench in the strength of the quasi-periodic potential, as well as a transition in the scaling properties of the quasi-stationary state at long times. Our results suggest a practical scheme for the experimental observation of many-body mobility edges using cold-atom setups.

  10. A new edge detection algorithm based on Canny idea

    Science.gov (United States)

    Feng, Yingke; Zhang, Jinmin; Wang, Siming

    2017-10-01

    The traditional Canny algorithm has poor self-adaptability threshold, and it is more sensitive to noise. In order to overcome these drawbacks, this paper proposed a new edge detection method based on Canny algorithm. Firstly, the media filtering and filtering based on the method of Euclidean distance are adopted to process it; secondly using the Frei-chen algorithm to calculate gradient amplitude; finally, using the Otsu algorithm to calculate partial gradient amplitude operation to get images of thresholds value, then find the average of all thresholds that had been calculated, half of the average is high threshold value, and the half of the high threshold value is low threshold value. Experiment results show that this new method can effectively suppress noise disturbance, keep the edge information, and also improve the edge detection accuracy.

  11. Adaptive Pseudo Dilation for Gestalt Edge Grouping and Contour Detection

    NARCIS (Netherlands)

    Papari, Giuseppe; Petkov, Nicolai

    2008-01-01

    We consider the problem of detecting object contours in natural images. In many cases, local luminance changes turn out to be stronger in textured areas than on object contours. Therefore, local edge features, which only look at a small neighborhood of each pixel, cannot be reliable indicators of

  12. Edge detection versus densitometry for assessing coronary stenting quantitatively

    NARCIS (Netherlands)

    B.H. Strauss (Bradley); Y. Juilliere; B.J.W.M. Rensing (Benno); J.H.C. Reiber (Johan); P.W.J.C. Serruys (Patrick)

    1991-01-01

    textabstractThe optimal method used to analyze quantitatively the immediate angiographic results of coronary stenting in the coronary arteries has not been studied. Accordingly, minimal luminal cross-sectional area was determined by 2 methods, edge detection and densitometry, in 19 patients who

  13. Spectral Textile Detection in the VNIR/SWIR Band

    Science.gov (United States)

    2015-03-01

    which have spectral similarities to background vegetation , are generally more difficult to detect than animal fibers such as wool and artificial fibers...effectiveness at long ranges, and spectral dismount detection currently relies on detecting skin pixels. In scenarios where skin is not exposed, spectral...training set. Classifiers with optimized parameters are used to classify contact data with artificially added noise and remotely-sensed hyperspectral data

  14. Enhancing Community Detection By Affinity-based Edge Weighting Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Andy [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sanders, Geoffrey [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Henson, Van [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Vassilevski, Panayot [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-05

    Community detection refers to an important graph analytics problem of finding a set of densely-connected subgraphs in a graph and has gained a great deal of interest recently. The performance of current community detection algorithms is limited by an inherent constraint of unweighted graphs that offer very little information on their internal community structures. In this paper, we propose a new scheme to address this issue that weights the edges in a given graph based on recently proposed vertex affinity. The vertex affinity quantifies the proximity between two vertices in terms of their clustering strength, and therefore, it is ideal for graph analytics applications such as community detection. We also demonstrate that the affinity-based edge weighting scheme can improve the performance of community detection algorithms significantly.

  15. Spatial and Temporal Extent of Ion Spectral Structures at the Inner Edge of the Plasma Sheet

    Science.gov (United States)

    Ferradas, C.; Reeves, G. D.; Zhang, J.; Spence, H. E.; Kistler, L. M.; Larsen, B.; Skoug, R. M.; Funsten, H. O.

    2017-12-01

    Several ion spectral structures are observed near the inner edge of the plasma sheet and constitute the signatures of ion drift and loss in the highly dynamic environment of the inner magnetosphere. Their study helps us understand ion access and losses in this region. Several studies have found that these structures vary with geomagnetic activity, local time, and ion species, but their spatial and temporal extent remain undetermined. We use data from the Helium, Oxygen, Proton, and Electron (HOPE) mass spectrometers onboard the Van Allen Probes to analyze the spectral structures in the energy range of 1- 50 keV. HOPE measurements on both Van Allen Probes spacecraft enable us to resolve the extent of these ion structures in space and time. As the structures respond to changes in the convection electric field on a variety of time scales, the lapping of the two spacecraft on time scales of minutes to hours helps determine their spatial and temporal evolution.

  16. Edge detection methods based on generalized type-2 fuzzy logic

    CERN Document Server

    Gonzalez, Claudia I; Castro, Juan R; Castillo, Oscar

    2017-01-01

    In this book four new methods are proposed. In the first method the generalized type-2 fuzzy logic is combined with the morphological gra-dient technique. The second method combines the general type-2 fuzzy systems (GT2 FSs) and the Sobel operator; in the third approach the me-thodology based on Sobel operator and GT2 FSs is improved to be applied on color images. In the fourth approach, we proposed a novel edge detec-tion method where, a digital image is converted a generalized type-2 fuzzy image. In this book it is also included a comparative study of type-1, inter-val type-2 and generalized type-2 fuzzy systems as tools to enhance edge detection in digital images when used in conjunction with the morphologi-cal gradient and the Sobel operator. The proposed generalized type-2 fuzzy edge detection methods were tested with benchmark images and synthetic images, in a grayscale and color format. Another contribution in this book is that the generalized type-2 fuzzy edge detector method is applied in the preproc...

  17. Image edges detection through B-Spline filters

    International Nuclear Information System (INIS)

    Mastropiero, D.G.

    1997-01-01

    B-Spline signal processing was used to detect the edges of a digital image. This technique is based upon processing the image in the Spline transform domain, instead of doing so in the space domain (classical processing). The transformation to the Spline transform domain means finding out the real coefficients that makes it possible to interpolate the grey levels of the original image, with a B-Spline polynomial. There exist basically two methods of carrying out this interpolation, which produces the existence of two different Spline transforms: an exact interpolation of the grey values (direct Spline transform), and an approximated interpolation (smoothing Spline transform). The latter results in a higher smoothness of the gray distribution function defined by the Spline transform coefficients, and is carried out with the aim of obtaining an edge detection algorithm which higher immunity to noise. Finally the transformed image was processed in order to detect the edges of the original image (the gradient method was used), and the results of the three methods (classical, direct Spline transform and smoothing Spline transform) were compared. The results were that, as expected, the smoothing Spline transform technique produced a detection algorithm more immune to external noise. On the other hand the direct Spline transform technique, emphasizes more the edges, even more than the classical method. As far as the consuming time is concerned, the classical method is clearly the fastest one, and may be applied whenever the presence of noise is not important, and whenever edges with high detail are not required in the final image. (author). 9 refs., 17 figs., 1 tab

  18. Spectrally narrowed leaky waveguide edge emission and transient electrluminescent dynamics of OLEDs

    International Nuclear Information System (INIS)

    Zhengqing, Gan

    2010-01-01

    In summary, there are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs. Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication. The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is narrow, and below which the spectrum is broad. The FWHM of spectrum depends on the material of the organic thin films, the thickness of the organic layers, and length of the OLED device. A superlinear relationship between the output intensity of the edge emission and the length of the device was observed, which is probably due to the misalignment of the device edge and the optical fiber detector. The original motivation of this research is for organic semiconductor laser that hasn't been realized due to the extremely high photon absorption in OLED devices. Although we didn't succeed in fabricating an electrically pumped organic laser diode, we made a comprehensive research in edge emission of OLEDs which provides valuable results in understanding light distribution and propagation in OLED devices. Chapter 5 focuses on the second project. A strong spike was observed at the falling edge of a pulse, and a long tail followed. The spike was due to the recombination of correlated charge pair (CCP) created by trapped carriers in guest molecules of the recombination zone. When the bias was turned off, along with the decreasing of electric field in the device, the electric field induced quenching decreases and the recombination rate of the CCP increases which result in the spike. This research project provides a

  19. Spectrally narrowed leaky waveguide edge emission and transient electrluminescent dynamics of OLEDs

    Energy Technology Data Exchange (ETDEWEB)

    Zhengqing, Gan [Iowa State Univ., Ames, IA (United States)

    2010-01-01

    In summary, there are two major research works presented in this dissertation. The first research project (Chapter 4) is spectrally narrowed edge emission from Organic Light Emitting Diodes. The second project (Chapter 5) is about transient electroluminescent dynamics in OLEDs. Chapter 1 is a general introduction of OLEDs. Chapter 2 is a general introduction of organic semiconductor lasers. Chapter 3 is a description of the thermal evaporation method for OLED fabrication. The detail of the first project was presented in Chapter 4. Extremely narrowed spectrum was observed from the edge of OLED devices. A threshold thickness exists, above which the spectrum is narrow, and below which the spectrum is broad. The FWHM of spectrum depends on the material of the organic thin films, the thickness of the organic layers, and length of the OLED device. A superlinear relationship between the output intensity of the edge emission and the length of the device was observed, which is probably due to the misalignment of the device edge and the optical fiber detector. The original motivation of this research is for organic semiconductor laser that hasn't been realized due to the extremely high photon absorption in OLED devices. Although we didn't succeed in fabricating an electrically pumped organic laser diode, we made a comprehensive research in edge emission of OLEDs which provides valuable results in understanding light distribution and propagation in OLED devices. Chapter 5 focuses on the second project. A strong spike was observed at the falling edge of a pulse, and a long tail followed. The spike was due to the recombination of correlated charge pair (CCP) created by trapped carriers in guest molecules of the recombination zone. When the bias was turned off, along with the decreasing of electric field in the device, the electric field induced quenching decreases and the recombination rate of the CCP increases which result in the spike. This research project provides

  20. A Geometric Algebra Co-Processor for Color Edge Detection

    Directory of Open Access Journals (Sweden)

    Biswajit Mishra

    2015-01-01

    Full Text Available This paper describes advancement in color edge detection, using a dedicated Geometric Algebra (GA co-processor implemented on an Application Specific Integrated Circuit (ASIC. GA provides a rich set of geometric operations, giving the advantage that many signal and image processing operations become straightforward and the algorithms intuitive to design. The use of GA allows images to be represented with the three R, G, B color channels defined as a single entity, rather than separate quantities. A novel custom ASIC is proposed and fabricated that directly targets GA operations and results in significant performance improvement for color edge detection. Use of the hardware described in this paper also shows that the convolution operation with the rotor masks within GA belongs to a class of linear vector filters and can be applied to image or speech signals. The contribution of the proposed approach has been demonstrated by implementing three different types of edge detection schemes on the proposed hardware. The overall performance gains using the proposed GA Co-Processor over existing software approaches are more than 3.2× faster than GAIGEN and more than 2800× faster than GABLE. The performance of the fabricated GA co-processor is approximately an order of magnitude faster than previously published results for hardware implementations.

  1. [Spectral features analysis of Pinus massoniana with pest of Dendrolimus punctatus Walker and levels detection].

    Science.gov (United States)

    Xu, Zhang-Hua; Liu, Jian; Yu, Kun-Yong; Gong, Cong-Hong; Xie, Wan-Jun; Tang, Meng-Ya; Lai, Ri-Wen; Li, Zeng-Lu

    2013-02-01

    Taking 51 field measured hyperspectral data with different pest levels in Yanping, Fujian Province as objects, the spectral reflectance and first derivative features of 4 levels of healthy, mild, moderate and severe insect pest were analyzed. On the basis of 7 detecting parameters construction, the pest level detecting models were built. The results showed that (1) the spectral reflectance of Pinus massoniana with pests were significantly lower than that of healthy state, and the higher the pest level, the lower the reflectance; (2) with the increase in pest level, the spectral reflectance curves' "green peak" and "red valley" of Pinus massoniana gradually disappeared, and the red edge was leveleds (3) the pest led to spectral "green peak" red shift, red edge position blue shift, but the changes in "red valley" and near-infrared position were complicated; (4) CARI, RES, REA and REDVI were highly relevant to pest levels, and the correlations between REP, RERVI, RENDVI and pest level were weak; (5) the multiple linear regression model with the variables of the 7 detection parameters could effectively detect the pest levels of Dendrolimus punctatus Walker, with both the estimation rate and accuracy above 0.85.

  2. Modulation of EEG spectral edge frequency during patterned pneumatic oral stimulation in preterm infants

    Science.gov (United States)

    Song, Dongli; Jegatheesan, Priya; Weiss, Sunshine; Govindaswami, Balaji; Wang, Jingyan; Lee, Jaehoon; Oder, Austin; Barlow, Steven M

    2014-01-01

    Background Stimulation of the nervous system plays a central role in brain development and neurodevelopmental outcome. Thalamocortical and corticocortical development is diminished in premature infants and correlated to electroencephalography (EEG) progression. The purpose of this study was to determine the effects of orocutaneous stimulation on the modulation of spectral edge frequency, fc=90% (SEF-90) derived from EEG recordings in preterm infants. Methods Twenty two preterm infants were randomized to experimental and control conditions. Pulsed orocutaneous stimulation was presented during gavage feedings begun at around 32 weeks postmenstrual age (PMA). The SEF-90 was derived from 2-channel EEG recordings. Results Compared to the control condition, the pulsed orocutaneous stimulation produced a significant reorganization of SEF-90 in the left (p = 0.005) and right (p stimulation also produced a significant pattern of short term cortical adaptation and a long term neural adaptation manifest as a 0.5 Hz elevation in SEF-90 after repeated stimulation sessions. Conclusion This is the first study to demonstrate the modulating effects of a servo-controlled oral somatosensory input on the spectral features of EEG activity in preterm infants. PMID:24129553

  3. Small Pitch Transition-Edge Sensors with Broadband High Spectral Resolution for Solar Physics

    Science.gov (United States)

    Smith, S. J.; Adams, J. S.; Eckart, M. E.; Smith, Adams; Bailey, C. N.; Bandler, S. R.; Chevenak, J. A.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.; hide

    2012-01-01

    We are developing small pitch transition-edge sensor (TES) X-ray detectors optimized for solar astronomy. These devices are fabricated on thick Si substrates with embedded Cu heat-sink layer. We use 35 x 35 square micrometers Mo/Au TESs with 4.5 micrometer thick Au absorbers. We have tested devices with different geometric absorber stem contact areas with the TES and surrounding substrate area. This allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between thc stem contact area and a broadening in the spectral line shape indicative of athermal phonon loss. When the contact area is minimized we have obtained exceptional broadband spectral resolution of 1.28 plus or minus 0.03 eV at an energy of 1.5 keV, 1.58 plus or minus 0.07 eV at 5.9 keV and 1.96 plus or minus 0.08 eV at 8 keV. The linearity in the measured gain scale is understood in the context of the longitudinal proximity effect from the electrical bias leads resulting in transition characteristics that are strongly dependent upon TES size.

  4. Detection of Fusarium in single wheat kernels using spectral Imaging

    NARCIS (Netherlands)

    Polder, G.; Heijden, van der G.W.A.M.; Waalwijk, C.; Young, I.T.

    2005-01-01

    Fusarium head blight (FHB) is a harmful fungal disease that occurs in small grains. Non-destructive detection of this disease is traditionally done using spectroscopy or image processing. In this paper the combination of these two in the form of spectral imaging is evaluated. Transmission spectral

  5. A heuristic approach to edge detection in on-line portal imaging

    International Nuclear Information System (INIS)

    McGee, Kiaran P.; Schultheiss, Timothy E.; Martin, Eric E.

    1995-01-01

    Purpose: Portal field edge detection is an essential component of several postprocessing techniques used in on-line portal imaging, including field shape verification, selective contrast enhancement, and treatment setup error detection. Currently edge detection of successive fractions in a multifraction portal image series involves the repetitive application of the same algorithm. As the number of changes in the field is small compared to the total number of fractions, standard edge detection algorithms essentially recalculate the same field shape numerous times. A heuristic approach to portal edge detection has been developed that takes advantage of the relatively few changes in the portal field shape throughout a fractionation series. Methods and Materials: The routine applies a standard edge detection routine to calculate an initial field edge and saves the edge information. Subsequent fractions are processed by applying an edge detection operator over a small region about each point of the previously defined contour, to determine any shifts in the field shape in the new image. Failure of this edge check indicates that a significant change in the field edge has occurred, and the original edge detection routine is applied to the image. Otherwise the modified edge contour is used to define the new edge. Results: Two hundred and eighty-one portal images collected from an electronic portal imaging device were processed by the edge detection routine. The algorithm accurately calculated each portal field edge, as well as reducing processing time in subsequent fractions of an individual portal field by a factor of up to 14. Conclusions: The heuristic edge detection routine is an accurate and fast method for calculating portal field edges and determining field edge setup errors

  6. ADAPTIVE ANT COLONY OPTIMIZATION BASED GRADIENT FOR EDGE DETECTION

    Directory of Open Access Journals (Sweden)

    Febri Liantoni

    2014-08-01

    Full Text Available Ant Colony Optimization (ACO is a nature-inspired optimization algorithm which is motivated by ants foraging behavior. Due to its favorable advantages, ACO has been widely used to solve several NP-hard problems, including edge detection. Since ACO initially distributes ants at random, it may cause imbalance ant distribution which later affects path discovery process. In this paper an adaptive ACO is proposed to optimize edge detection by adaptively distributing ant according to gradient analysis. Ants are adaptively distributed according to gradient ratio of each image regions. Region which has bigger gradient ratio, will have bigger number of ant distribution. Experiments are conducted using images from various datasets. Precision and recall are used to quantitatively evaluate performance of the proposed algorithm. Precision and recall of adaptive ACO reaches 76.98 % and 96.8 %. Whereas highest precision and recall for standard ACO are 69.74 % and 74.85 %. Experimental results show that the adaptive ACO outperforms standard ACO which randomly distributes ants.

  7. Single-photon light detection with transition-edge sensors

    International Nuclear Information System (INIS)

    Rajteri, M.; Taralli, E.; Portesi, C.; Monticone, E.

    2008-01-01

    Transition-Edge Sensors (TESs) are micro calorimeters that measure the energy of incident single-photons by the resistance increase of a superconducting film biased within the superconducting-to-normal transition. TES are able to detect single photons from x-ray to IR with an intrinsic energy resolution and photon-number discrimination capability. Metrological, astronomical and quantum communication applications are the fields where these properties can be particularly important. In this work, we report about characterization of different TESs based on Ti films. Single-photons have been detected from 200 nm to 800 nm working at T c ∼ 100 m K. Using a pulsed laser at 690 nm we have demonstrated the capability to resolve up to five photons.

  8. A divisive spectral method for network community detection

    International Nuclear Information System (INIS)

    Cheng, Jianjun; Li, Longjie; Yao, Yukai; Chen, Xiaoyun; Leng, Mingwei; Lu, Weiguo

    2016-01-01

    Community detection is a fundamental problem in the domain of complex network analysis. It has received great attention, and many community detection methods have been proposed in the last decade. In this paper, we propose a divisive spectral method for identifying community structures from networks which utilizes a sparsification operation to pre-process the networks first, and then uses a repeated bisection spectral algorithm to partition the networks into communities. The sparsification operation makes the community boundaries clearer and sharper, so that the repeated spectral bisection algorithm extract high-quality community structures accurately from the sparsified networks. Experiments show that the combination of network sparsification and a spectral bisection algorithm is highly successful, the proposed method is more effective in detecting community structures from networks than the others. (paper: interdisciplinary statistical mechanics)

  9. Image Segmentation Based on Constrained Spectral Variance Difference and Edge Penalty

    Directory of Open Access Journals (Sweden)

    Bo Chen

    2015-05-01

    Full Text Available Segmentation, which is usually the first step in object-based image analysis (OBIA, greatly influences the quality of final OBIA results. In many existing multi-scale segmentation algorithms, a common problem is that under-segmentation and over-segmentation always coexist at any scale. To address this issue, we propose a new method that integrates the newly developed constrained spectral variance difference (CSVD and the edge penalty (EP. First, initial segments are produced by a fast scan. Second, the generated segments are merged via a global mutual best-fitting strategy using the CSVD and EP as merging criteria. Finally, very small objects are merged with their nearest neighbors to eliminate the remaining noise. A series of experiments based on three sets of remote sensing images, each with different spatial resolutions, were conducted to evaluate the effectiveness of the proposed method. Both visual and quantitative assessments were performed, and the results show that large objects were better preserved as integral entities while small objects were also still effectively delineated. The results were also found to be superior to those from eCongnition’s multi-scale segmentation.

  10. Spectral imaging for contamination detection in food

    DEFF Research Database (Denmark)

    Carstensen, Jens Michael

    application of the technique is finding anomalies I supposedly homogeneous matter or homogeneous mixtures. This application occurs frequently in the food industry when different types of contamination are to be detected. Contaminants could be e.g. foreign matter, process-induced toxins, and microbiological...... spoilage. Many of these contaminants may be detected in the wavelength range visible to normal silicium-based camera sensors i.e. 350-1050 nm with proper care during sample preparation, sample presentation, image acquisition and analysis. This presentation will give an introduction to the techniques behind...

  11. Spectral anomaly methods for aerial detection using KUT nuisance rejection

    International Nuclear Information System (INIS)

    Detwiler, R.S.; Pfund, D.M.; Myjak, M.J.; Kulisek, J.A.; Seifert, C.E.

    2015-01-01

    This work discusses the application and optimization of a spectral anomaly method for the real-time detection of gamma radiation sources from an aerial helicopter platform. Aerial detection presents several key challenges over ground-based detection. For one, larger and more rapid background fluctuations are typical due to higher speeds, larger field of view, and geographically induced background changes. As well, the possible large altitude or stand-off distance variations cause significant steps in background count rate as well as spectral changes due to increased gamma-ray scatter with detection at higher altitudes. The work here details the adaptation and optimization of the PNNL-developed algorithm Nuisance-Rejecting Spectral Comparison Ratios for Anomaly Detection (NSCRAD), a spectral anomaly method previously developed for ground-based applications, for an aerial platform. The algorithm has been optimized for two multi-detector systems; a NaI(Tl)-detector-based system and a CsI detector array. The optimization here details the adaptation of the spectral windows for a particular set of target sources to aerial detection and the tailoring for the specific detectors. As well, the methodology and results for background rejection methods optimized for the aerial gamma-ray detection using Potassium, Uranium and Thorium (KUT) nuisance rejection are shown. Results indicate that use of a realistic KUT nuisance rejection may eliminate metric rises due to background magnitude and spectral steps encountered in aerial detection due to altitude changes and geographically induced steps such as at land–water interfaces

  12. Electronic spectral detection in liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Biggs, Wilton R. [ChevronTexaco Chemical Co., P. O. Box 1627, Richmond, CA 94802 (United States); Fetzer, John C. [Fetzpahs Consulting, 1283 Santa Fe St., Hercules, CA 94547 (United States)

    2002-07-01

    The use of absorbance and fluorescence spectrometers as liquid chromatography detectors is described. These detectors offer sensitive detection that can also identify the peaks in a chromatogram. Many examples, mainly from the separation of polycyclic aromatic hydrocarbons, are given that show the selectivity and usefulness of these detectors. (orig.)

  13. Red-Edge Spectral Reflectance as an Indicator of Surface Moisture Content in an Alaskan Peatland Ecosystem

    Science.gov (United States)

    McPartland, M.; Kane, E. S.; Turetsky, M. R.; Douglass, T.; Falkowski, M. J.; Montgomery, R.; Edwards, J.

    2015-12-01

    Arctic and boreal peatlands serve as major reservoirs of terrestrial organic carbon (C) because Net Primary Productivity (NPP) outstrips C loss from decomposition over long periods of time. Peatland productivity varies as a function of water table position and surface moisture content, making C storage in these systems particularly vulnerable to the climate warming and drying predicted for high latitudes. Detailed spatial knowledge of how aboveground vegetation communities respond to changes in hydrology would allow for ecosystem response to environmental change to be measured at the landscape scale. This study leverages remotely sensed data along with field measurements taken at the Alaska Peatland Experiment (APEX) at the Bonanza Creek Long Term Ecological Research site to examine relationships between plant solar reflectance and surface moisture. APEX is a decade-long experiment investigating the effects of hydrologic change on peatland ecosystems using water table manipulation treatments (raised, lowered, and control). Water table levels were manipulated throughout the 2015 growing season, resulting in a maximum separation of 35 cm between raised and lowered treatment plots. Water table position, soil moisture content, depth to seasonal ice, soil temperature, photosynthetically active radiation (PAR), CO2 and CH4 fluxes were measured as predictors of C loss through decomposition and NPP. Vegetation was surveyed for percent cover of plant functional types. Remote sensing data was collected during peak growing season, when the separation between treatment plots was at maximum difference. Imagery was acquired via a SenseFly eBee airborne platform equipped with a Canon S110 red-edge camera capable of detecting spectral reflectance from plant tissue at 715 nm band center to within centimeters of spatial resolution. Here, we investigate empirical relationships between spectral reflectance, water table position, and surface moisture in relation to peat carbon balance.

  14. Edge detection of solid motor' CT image based on gravitation model

    International Nuclear Information System (INIS)

    Yu Guanghui; Lu Hongyi; Zhu Min; Liu Xudong; Hou Zhiqiang

    2012-01-01

    In order to detect the edge of solid motor' CT image much better, a new edge detection operator base on gravitation model was put forward. The edge of CT image is got by the new operator. The superiority turned out by comparing the edge got by ordinary operator. The comparison among operators with different size shows that higher quality CT images need smaller size operator while the lower need the larger. (authors)

  15. Detecting Weak Spectral Lines in Interferometric Data through Matched Filtering

    Science.gov (United States)

    Loomis, Ryan A.; Öberg, Karin I.; Andrews, Sean M.; Walsh, Catherine; Czekala, Ian; Huang, Jane; Rosenfeld, Katherine A.

    2018-04-01

    Modern radio interferometers enable observations of spectral lines with unprecedented spatial resolution and sensitivity. In spite of these technical advances, many lines of interest are still at best weakly detected and therefore necessitate detection and analysis techniques specialized for the low signal-to-noise ratio (S/N) regime. Matched filters can leverage knowledge of the source structure and kinematics to increase sensitivity of spectral line observations. Application of the filter in the native Fourier domain improves S/N while simultaneously avoiding the computational cost and ambiguities associated with imaging, making matched filtering a fast and robust method for weak spectral line detection. We demonstrate how an approximate matched filter can be constructed from a previously observed line or from a model of the source, and we show how this filter can be used to robustly infer a detection significance for weak spectral lines. When applied to ALMA Cycle 2 observations of CH3OH in the protoplanetary disk around TW Hya, the technique yields a ≈53% S/N boost over aperture-based spectral extraction methods, and we show that an even higher boost will be achieved for observations at higher spatial resolution. A Python-based open-source implementation of this technique is available under the MIT license at http://github.com/AstroChem/VISIBLE.

  16. Fuzzy Logic Based Edge Detection in Smooth and Noisy Clinical Images.

    Directory of Open Access Journals (Sweden)

    Izhar Haq

    Full Text Available Edge detection has beneficial applications in the fields such as machine vision, pattern recognition and biomedical imaging etc. Edge detection highlights high frequency components in the image. Edge detection is a challenging task. It becomes more arduous when it comes to noisy images. This study focuses on fuzzy logic based edge detection in smooth and noisy clinical images. The proposed method (in noisy images employs a 3 × 3 mask guided by fuzzy rule set. Moreover, in case of smooth clinical images, an extra mask of contrast adjustment is integrated with edge detection mask to intensify the smooth images. The developed method was tested on noise-free, smooth and noisy images. The results were compared with other established edge detection techniques like Sobel, Prewitt, Laplacian of Gaussian (LOG, Roberts and Canny. When the developed edge detection technique was applied to a smooth clinical image of size 270 × 290 pixels having 24 dB 'salt and pepper' noise, it detected very few (22 false edge pixels, compared to Sobel (1931, Prewitt (2741, LOG (3102, Roberts (1451 and Canny (1045 false edge pixels. Therefore it is evident that the developed method offers improved solution to the edge detection problem in smooth and noisy clinical images.

  17. Defect detection based on extreme edge of defective region histogram

    Directory of Open Access Journals (Sweden)

    Zouhir Wakaf

    2018-01-01

    Full Text Available Automatic thresholding has been used by many applications in image processing and pattern recognition systems. Specific attention was given during inspection for quality control purposes in various industries like steel processing and textile manufacturing. Automatic thresholding problem has been addressed well by the commonly used Otsu method, which provides suitable results for thresholding images based on a histogram of bimodal distribution. However, the Otsu method fails when the histogram is unimodal or close to unimodal. Defects have different shapes and sizes, ranging from very small to large. The gray-level distributions of the image histogram can vary between unimodal and multimodal. Furthermore, Otsu-revised methods, like the valley-emphasis method and the background histogram mode extents, which overcome the drawbacks of the Otsu method, require preprocessing steps and fail to use the general threshold for multimodal defects. This study proposes a new automatic thresholding algorithm based on the acquisition of the defective region histogram and the selection of its extreme edge as the threshold value to segment all defective objects in the foreground from the image background. To evaluate the proposed defect-detection method, common standard images for experimentation were used. Experimental results of the proposed method show that the proposed method outperforms the current methods in terms of defect detection.

  18. Detecting gallbladders in chicken livers using spectral analysis

    DEFF Research Database (Denmark)

    Jørgensen, Anders; Mølvig Jensen, Eigil; Moeslund, Thomas B.

    2015-01-01

    This paper presents a method for detecting gallbladders attached to chicken livers using spectral imaging. Gallbladders can contaminate good livers, making them unfit for human consumption. A data set consisting of chicken livers with and without gallbladders, has been captured using 33 wavelengths...

  19. Image edge detection based tool condition monitoring with morphological component analysis.

    Science.gov (United States)

    Yu, Xiaolong; Lin, Xin; Dai, Yiquan; Zhu, Kunpeng

    2017-07-01

    The measurement and monitoring of tool condition are keys to the product precision in the automated manufacturing. To meet the need, this study proposes a novel tool wear monitoring approach based on the monitored image edge detection. Image edge detection has been a fundamental tool to obtain features of images. This approach extracts the tool edge with morphological component analysis. Through the decomposition of original tool wear image, the approach reduces the influence of texture and noise for edge measurement. Based on the target image sparse representation and edge detection, the approach could accurately extract the tool wear edge with continuous and complete contour, and is convenient in charactering tool conditions. Compared to the celebrated algorithms developed in the literature, this approach improves the integrity and connectivity of edges, and the results have shown that it achieves better geometry accuracy and lower error rate in the estimation of tool conditions. Copyright © 2017 ISA. Published by Elsevier Ltd. All rights reserved.

  20. Coastline change mapping using a spectral band method and Sobel edge operator

    Science.gov (United States)

    Al-Mansoori, Saeed; Al-Marzouqi, Fatima

    2016-10-01

    Coastline extraction has become an essential activity in wake of the natural disasters taking place in some regions such as tsunami, flooding etc. Salient feature of such catastrophes is lack of reaction time available for combating emergency, thus it is the endeavor of any country to develop constant monitoring mechanism of shorelines. This is a challenging task because of the magnitude of changes taking place to the coastline regularly. Previous research findings highlight a need of formulating automation driven methodology for timely and accurate detection of alterations in the coastline impacting sustainability of mankind operating in the coastal zone. In this study, we propose a new approach for automatic extraction of the coastline using remote sensing data. This approach is composed of three main stages. Firstly, classifying pixels of the image into two categories i.e. land and water body by applying two normalized difference indices i.e. Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI). Then, the process of binary conversion of classified image takes place using a local threshold method. Finally, the coastline is extracted by applying Sobel edge operator with a pair of (3×3) kernels. The approach is tested using 2.5m DubaiSat-1 (DS1) and DubaiSat-2 (DS2) images captured to detect and monitor the changes occurring along Dubai coastal zone within a period of six years from 2009 till 2015. Experimental results prove that the approach is capable of extracting the coastlines from DS1 and DS2 images with moderate human interaction. The results of the study show an increase of 6% in Dubai shoreline resulting on account of numerous man-made infrastructure development projects in tourism and allied sectors.

  1. Sub-surface defects detection of by using active thermography and advanced image edge detection

    International Nuclear Information System (INIS)

    Tse, Peter W.; Wang, Gaochao

    2017-01-01

    Active or pulsed thermography is a popular non-destructive testing (NDT) tool for inspecting the integrity and anomaly of industrial equipment. One of the recent research trends in using active thermography is to automate the process in detecting hidden defects. As of today, human effort has still been using to adjust the temperature intensity of the thermo camera in order to visually observe the difference in cooling rates caused by a normal target as compared to that by a sub-surface crack exists inside the target. To avoid the tedious human-visual inspection and minimize human induced error, this paper reports the design of an automatic method that is capable of detecting subsurface defects. The method used the technique of active thermography, edge detection in machine vision and smart algorithm. An infrared thermo-camera was used to capture a series of temporal pictures after slightly heating up the inspected target by flash lamps. Then the Canny edge detector was employed to automatically extract the defect related images from the captured pictures. The captured temporal pictures were preprocessed by a packet of Canny edge detector and then a smart algorithm was used to reconstruct the whole sequences of image signals. During the processes, noise and irrelevant backgrounds exist in the pictures were removed. Consequently, the contrast of the edges of defective areas had been highlighted. The designed automatic method was verified by real pipe specimens that contains sub-surface cracks. After applying such smart method, the edges of cracks can be revealed visually without the need of using manual adjustment on the setting of thermo-camera. With the help of this automatic method, the tedious process in manually adjusting the colour contract and the pixel intensity in order to reveal defects can be avoided. (paper)

  2. Gamelan Music Onset Detection based on Spectral Features

    Directory of Open Access Journals (Sweden)

    Yoyon Kusnendar Suprapto

    2013-03-01

    Full Text Available This research detects onsets of percussive instruments by examining the performance on the sound signals of gamelan instruments as one of traditional music instruments in Indonesia. Onset plays important role in determining musical rythmic structure, like beat, tempo, and is highly required in many applications of music information retrieval. There are four onset detection methods compared that employ spectral features, such as magnitude, phase, and the combination of both, which are phase slope (PS, weighted phase deviation (WPD, spectral flux (SF, and rectified complex domain (RCD. These features are extracted by representing the sound signals into time-frequency domain using overlapped Short-time Fourier Transform (STFT and varying the window length. Onset detection functions are processed through peak-picking using dynamic threshold. The results showed that by using suitable window length and parameter setting of dynamic threshold, F-measure which is greater than 0.80 can be obtained for certain methods.

  3. Self-similar spectral structures and edge-locking hierarchy in open-boundary spin chains

    International Nuclear Information System (INIS)

    Haque, Masudul

    2010-01-01

    For an anisotropic Heisenberg (XXZ) spin chain, we show that an open boundary induces a series of approximately self-similar features at different energy scales, high up in the eigenvalue spectrum. We present a nonequilibrium phenomenon related to this fractal structure, involving states in which a connected block near the edge is polarized oppositely to the rest of the chain. We show that such oppositely polarized blocks can be 'locked' to the edge of the spin chain and that there is a hierarchy of edge-locking effects at various orders of the anisotropy. The phenomenon enables dramatic control of quantum-state transmission and magnetization control.

  4. Spectral autofluorescence imaging of the retina for drusen detection

    Science.gov (United States)

    Foubister, James J.; Gorman, Alistair; Harvey, Andy; Hemert, Jano van

    2018-02-01

    The presence and characteristics of drusen in retinal images, namely their size, location, and distribution, can be used to aid in the diagnosis and monitoring of Age Related Macular Degeneration (AMD); one of the leading causes for blindness in the elderly population. Current imaging techniques are effective at determining the presence and number of drusen, but fail when it comes to classifying their size and form. These distinctions are important for correctly characterising the disease, especially in the early stages where the development of just one larger drusen can indicate progression. Another challenge for automated detection is in distinguishing them from other retinal features, such as cotton wool spots. We describe the development of a multi-spectral scanning-laser ophthalmoscope that records images of retinal autofluorescence (AF) in four spectral bands. This will offer the potential to detect drusen with improved contrast based on spectral discrimination for automated classification. The resulting improved specificity and sensitivity for their detection offers more reliable characterisation of AMD. We present proof of principle images prior to further system optimisation and clinical trials for assessment of enhanced detection of drusen.

  5. Camouflaged target detection based on polarized spectral features

    Science.gov (United States)

    Tan, Jian; Zhang, Junping; Zou, Bin

    2016-05-01

    The polarized hyperspectral images (PHSI) include polarization, spectral, spatial and radiant features, which provide more information about objects and scenes than traditional intensity or spectrum ones. And polarization can suppress the background and highlight the object, leading to the high potential to improve camouflaged target detection. So polarized hyperspectral imaging technique has aroused extensive concern in the last few years. Nowadays, the detection methods are still not very mature, most of which are rooted in the detection of hyperspectral image. And before using these algorithms, Stokes vector is used to process the original four-dimensional polarized hyperspectral data firstly. However, when the data is large and complex, the amount of calculation and error will increase. In this paper, tensor is applied to reconstruct the original four-dimensional data into new three-dimensional data, then, the constraint energy minimization (CEM) is used to process the new data, which adds the polarization information to construct the polarized spectral filter operator and takes full advantages of spectral and polarized information. This way deals with the original data without extracting the Stokes vector, so as to reduce the computation and error greatly. The experimental results also show that the proposed method in this paper is more suitable for the target detection of the PHSI.

  6. Fast algorithm for probabilistic bone edge detection (FAPBED)

    Science.gov (United States)

    Scepanovic, Danilo; Kirshtein, Joshua; Jain, Ameet K.; Taylor, Russell H.

    2005-04-01

    The registration of preoperative CT to intra-operative reality systems is a crucial step in Computer Assisted Orthopedic Surgery (CAOS). The intra-operative sensors include 3D digitizers, fiducials, X-rays and Ultrasound (US). FAPBED is designed to process CT volumes for registration to tracked US data. Tracked US is advantageous because it is real time, noninvasive, and non-ionizing, but it is also known to have inherent inaccuracies which create the need to develop a framework that is robust to various uncertainties, and can be useful in US-CT registration. Furthermore, conventional registration methods depend on accurate and absolute segmentation. Our proposed probabilistic framework addresses the segmentation-registration duality, wherein exact segmentation is not a prerequisite to achieve accurate registration. In this paper, we develop a method for fast and automatic probabilistic bone surface (edge) detection in CT images. Various features that influence the likelihood of the surface at each spatial coordinate are combined using a simple probabilistic framework, which strikes a fair balance between a high-level understanding of features in an image and the low-level number crunching of standard image processing techniques. The algorithm evaluates different features for detecting the probability of a bone surface at each voxel, and compounds the results of these methods to yield a final, low-noise, probability map of bone surfaces in the volume. Such a probability map can then be used in conjunction with a similar map from tracked intra-operative US to achieve accurate registration. Eight sample pelvic CT scans were used to extract feature parameters and validate the final probability maps. An un-optimized fully automatic Matlab code runs in five minutes per CT volume on average, and was validated by comparison against hand-segmented gold standards. The mean probability assigned to nonzero surface points was 0.8, while nonzero non-surface points had a mean

  7. Assessing the role of spectral and intensity cues in spectral ripple detection and discrimination in cochlear-implant users.

    Science.gov (United States)

    Anderson, Elizabeth S; Oxenham, Andrew J; Nelson, Peggy B; Nelson, David A

    2012-12-01

    Measures of spectral ripple resolution have become widely used psychophysical tools for assessing spectral resolution in cochlear-implant (CI) listeners. The objective of this study was to compare spectral ripple discrimination and detection in the same group of CI listeners. Ripple detection thresholds were measured over a range of ripple frequencies and were compared to spectral ripple discrimination thresholds previously obtained from the same CI listeners. The data showed that performance on the two measures was correlated, but that individual subjects' thresholds (at a constant spectral modulation depth) for the two tasks were not equivalent. In addition, spectral ripple detection was often found to be possible at higher rates than expected based on the available spectral cues, making it likely that temporal-envelope cues played a role at higher ripple rates. Finally, spectral ripple detection thresholds were compared to previously obtained speech-perception measures. Results confirmed earlier reports of a robust relationship between detection of widely spaced ripples and measures of speech recognition. In contrast, intensity difference limens for broadband noise did not correlate with spectral ripple detection measures, suggesting a dissociation between the ability to detect small changes in intensity across frequency and across time.

  8. Leak detection in pipelines through spectral analysis of pressure signals

    Directory of Open Access Journals (Sweden)

    Souza A.L.

    2000-01-01

    Full Text Available The development and test of a technique for leak detection in pipelines is presented. The technique is based on the spectral analysis of pressure signals measured in pipeline sections where the formation of stationary waves is favoured, allowing leakage detection during the start/stop of pumps. Experimental tests were performed in a 1250 m long pipeline for various operational conditions of the pipeline (liquid flow rate and leakage configuration. Pressure transients were obtained by four transducers connected to a PC computer. The obtained results show that the spectral analysis of pressure transients, together with the knowledge of reflection points provide a simple and efficient way of identifying leaks during the start/stop of pumps in pipelines.

  9. Outlier Detection with Space Transformation and Spectral Analysis

    DEFF Research Database (Denmark)

    Dang, Xuan-Hong; Micenková, Barbora; Assent, Ira

    2013-01-01

    which rely on notions of distances or densities, this approach introduces a novel concept based on local quadratic entropy for evaluating the similarity of a data object with its neighbors. This information theoretic quantity is used to regularize the closeness amongst data instances and subsequently......Detecting a small number of outliers from a set of data observations is always challenging. In this paper, we present an approach that exploits space transformation and uses spectral analysis in the newly transformed space for outlier detection. Unlike most existing techniques in the literature...... benefits the process of mapping data into a usually lower dimensional space. Outliers are then identified by spectral analysis of the eigenspace spanned by the set of leading eigenvectors derived from the mapping procedure. The proposed technique is purely data-driven and imposes no assumptions regarding...

  10. External occulter edge scattering control using metamaterials for exoplanet detection

    Science.gov (United States)

    Bendek, Eduardo A.; Sirbu, Dan; Liu, Zhaowei; Martin, Stefan; Lu, Dylan

    2015-09-01

    Direct imaging of earth-like exoplanets in the Habitable Zone of sun-like stars requires image contrast of ~10^10 at angular separations of around a hundred milliarcseconds. One approach for achieving this performance is to fly a starshade at a long distance in front of the telescope, shading the telescope from the direct starlight, but allowing planets around the star to be seen. The starshade is positioned so that sunlight falls on the surface away from the telescope, so the sun does not directly illuminate it. However, sunlight scattered from the starshade edge can enter the telescope, raising the background light level and potentially preventing the starshade from delivering the required contrast. As a result, starshade edge design has been identified as one of the highest priority technology gaps for external occulter missions in the NASAs Exoplanet Exploration Program Technology Plan 2013. To reduce the sunlight edge scatter to an acceptable level, the edge Radius Of Curvature (ROC) should be 1μm or less (commercial razor blades have ROC of a few hundred nanometer). This poses a challenging manufacturing requirement and may make the occulter difficult to handle. In this paper we propose an alternative approach to controlling the edge scattering by applying a flexible metamaterial to the occulter edge. Metamaterials are artificially structured materials, which have been designed to display properties not found in natural materials. Metamaterials can be designed to direct the scatter at planned incident angles away from the space telescope, thereby directly decreasing the contaminating background light. Reduction of the background light translates into shorter integration time to characterize a target planet and therefore improves the efficiency of the observations. As an additional benefit, metamaterials also have potential to produce increased tolerance to edge defects.

  11. Spectral and energy efficiency analysis of uplink heterogeneous networks with small-cells on edge

    KAUST Repository

    Shakir, Muhammad Zeeshan; Tabassum, Hina; Qaraqe, Khalid A.; Serpedin, Erchin; Alouini, Mohamed-Slim

    2014-01-01

    by considering fast power control where the mobile users transmit with adaptive power to compensate the path loss, shadowing and fading. In particular, we develop a moment generating function (MGF) based approach to derive analytical bounds on the area spectral

  12. Curvature Effect and the Spectral Softening Phenomenon Detected ...

    Indian Academy of Sciences (India)

    soft spectral evolution, indicating that this spectral softening is not a rare phenomenon .... of time, there exists a temporal steep decay phase accompanied by spectral softening. (d) In most cases, the temporal power law index α and the spectral.

  13. Detection Range Estimation of UV Spectral Band Laser Radar

    Directory of Open Access Journals (Sweden)

    V. A. Gorodnichev

    2014-01-01

    Full Text Available Recently, has come into existence an interest in the systems operating in the ultra-violet (UF band of wavelengths, which use other spectral information (coefficients of reflection or radiation in UF range about location objects, than laser systems in the visible, near or average infrared bands. Thus, a point is not only to receive additional (in another spectral range information on location objects. Laser radiation in the UF spectral band of 0.315 – 0.4 microns is safer than laser radiation with the wavelengths of 0.38 – 1.4 microns.The work presents a comparative estimation of the detection systems range of laser radars in the UV and visible spectral bands for the following wavelengths of radiation:- UF band: 0.266 microns (the fourth harmonic of YAG-laser activated by neodymium ions, 0.308 microns (the XeCl-excimer laser, 0.355 microns (the third harmonic of YAG-laser activated by neodymium ions;- visible band: 0.532 microns (the second harmonic of YAG-laser activated by neodymium ions.Results of calculations show that for the horizontal pathway in the terrestrial atmosphere at the selected radiation wavelengths a detection range is in the range of 2510m – 5690 m.The maximum range of detection corresponds to the visible spectral band. A sweep range decreases with transition to the UF band. This is caused by the fact that with transition to the UF band there is a rise of atmosphere attenuation (generally, because of absorption by ozone, this effect being smoothed by reducing background radiation.In the UF band a wavelength of 0.355 microns is the most acceptable. For this wavelength a detection range is about 1,5 times less (in comparison with the visible band of 0.532 microns. However, this is the much more eye-safe wavelength. With transition to the UV band a detection range decreases not that much and can be compensated by changing parameters of transmitting or receiving channels of laser radar.

  14. Quantitative spectral K-edge imaging in preclinical photon-counting x-ray computed tomography.

    Science.gov (United States)

    de Vries, Anke; Roessl, Ewald; Kneepkens, Esther; Thran, Axel; Brendel, Bernhard; Martens, Gerhard; Proska, Roland; Nicolay, Klaas; Grüll, Holger

    2015-04-01

    The objective of this study was to investigate the feasibility and the accuracy of spectral computed tomography (spectral CT) to determine the tissue concentrations and localization of high-attenuation, iodine-based contrast agents in mice. Iodine tissue concentrations determined with spectral CT are compared with concentrations measured with single-photon emission computed tomography (SPECT) and inductively coupled plasma mass spectrometry (ICP-MS). All animal procedures were performed according to the US National Institutes of Health principles of laboratory animal care and were approved by the ethical review committee of Maastricht, The Netherlands. Healthy Swiss mice (n = 4) were injected with an iodinated emulsion radiolabeled with indium as multimodal contrast agent for CT and SPECT. The CT and SPECT scans were acquired using a dedicated small-animal SPECT/CT system. Subsequently, scans were performed with a preclinical spectral CT scanner equipped with a photon-counting detector and 6 energy threshold levels. Quantitative data analysis of SPECT and spectral CT scans were obtained using 3-dimensional volumes-of-interest drawing methods. The ICP-MS on dissected organs was performed to determine iodine uptake per organ and was compared with the amounts determined from spectral CT and SPECT. Iodine concentrations obtained with image-processed spectral CT data correlated well with data obtained either with noninvasive SPECT imaging (slope = 0.96, r = 0.75) or with ICP-MS (slope = 0.99, r = 0.89) in tissue samples. This preclinical proof-of-concept study shows the in vivo quantification of iodine concentrations in tissues using spectral CT. Our multimodal imaging approach with spectral CT and SPECT using radiolabeled iodinated emulsions together with ICP-based quantification allows a direct comparison of all methods. Benchmarked against ICP-MS data, spectral CT in the present implementation shows a slight underestimation of organ iodine concentrations compared

  15. Fast Image Edge Detection based on Faber Schauder Wavelet and Otsu Threshold

    Directory of Open Access Journals (Sweden)

    Assma Azeroual

    2017-12-01

    Full Text Available Edge detection is a critical stage in many computer vision systems, such as image segmentation and object detection. As it is difficult to detect image edges with precision and with low complexity, it is appropriate to find new methods for edge detection. In this paper, we take advantage of Faber Schauder Wavelet (FSW and Otsu threshold to detect edges in a multi-scale way with low complexity, since the extrema coefficients of this wavelet are located on edge points and contain only arithmetic operations. First, the image is smoothed using bilateral filter depending on noise estimation. Second, the FSW extrema coefficients are selected based on Otsu threshold. Finally, the edge points are linked using a predictive edge linking algorithm to get the image edges. The effectiveness of the proposed method is supported by the experimental results which prove that our method is faster than many competing state-of-the-art approaches and can be used in real-time applications.

  16. Spectral differential imaging detection of planets about nearby stars

    International Nuclear Information System (INIS)

    Smith, W.H.

    1987-01-01

    Direct ground-based optical imaging of planets in orbit about nearby stars may be accomplished by spectral differential imaging using multiple passband acoustooptic filters with a CCD. This technique provides two essential results. First, it provides a means to modulate the stellar flux reflected from a planet while leaving the flux from the star and other sources in the same field of view unmodulated. Second, spectral differential imaging enables the CCD detector to achieve a sufficiently high dynamic range to locate planets near a star in spite of an integrated brightness differential of 5 x 10 8 . Spectral differential imaging at nearby diffraction limited imaging conditions with telescope apodization can reduce the time to conduct a sensitive planetary search to a few hours in some cases. The feasibility of this idea is discussed here and shown to provide, in principle, the discrimination and sensitivity to detect a Jovian-class planet about stars at distances of about 10 parsecs. The detection of brown dwarfs is shown to be feasible as well. 31 references

  17. Anti-impulse-noise Edge Detection via Anisotropic Morphological Directional Derivatives.

    Science.gov (United States)

    Shui, Peng-Lang; Wang, Fu-Ping

    2017-07-13

    Traditional differential-based edge detection suffers from abrupt degradation in performance when images are corrupted by impulse noises. The morphological operators such as the median filters and weighted median filters possess the intrinsic ability to counteract impulse noise. In this paper, by combining the biwindow configuration with weighted median filters, anisotropic morphological directional derivatives (AMDD) robust to impulse noise are proposed to measure the local grayscale variation around a pixel. For ideal step edges, the AMDD spatial response and directional representation are derived. The characteristics and edge resolution of two kinds of typical biwindows are analyzed thoroughly. In terms of the AMDD spatial response and directional representation of ideal step edges, the spatial matched filter is used to extract the edge strength map (ESM) from the AMDDs of an image. The spatial and directional matched filters are used to extract the edge direction map (EDM). Embedding the extracted ESM and EDM into the standard route of the differential-based edge detection, an anti-impulse-noise AMDD-based edge detector is constructed. It is compared with the existing state-of-the-art detectors on a recognized image dataset for edge detection evaluation. The results show that it attains competitive performance in noise-free and Gaussian noise cases and the best performance in impulse noise cases.

  18. [Analysis of sensitive spectral bands for burning status detection using hyper-spectral images of Tiangong-01].

    Science.gov (United States)

    Qin, Xian-Lin; Zhu, Xi; Yang, Fei; Zhao, Kai-Rui; Pang, Yong; Li, Zeng-Yuan; Li, Xu-Zhi; Zhang, Jiu-Xing

    2013-07-01

    To obtain the sensitive spectral bands for detection of information on 4 kinds of burning status, i. e. flaming, smoldering, smoke, and fire scar, with satellite data, analysis was conducted to identify suitable satellite spectral bands for detection of information on these 4 kinds of burning status by using hyper-spectrum images of Tiangong-01 (TG-01) and employing a method combining statistics and spectral analysis. The results show that: in the hyper-spectral images of TG-01, the spectral bands differ obviously for detection of these 4 kinds of burning status; in all hyper-spectral short-wave infrared channels, the reflectance of flaming is higher than that of all other 3 kinds of burning status, and the reflectance of smoke is the lowest; the reflectance of smoke is higher than that of all other 3 kinds of burning status in the channels corresponding to hyper-spectral visible near-infrared and panchromatic sensors. For spectral band selection, more suitable spectral bands for flaming detection are 1 000.0-1 956.0 and 2 020.0-2 400.0 nm; the suitable spectral bands for identifying smoldering are 930.0-1 000.0 and 1 084.0-2 400.0 nm; the suitable spectral bands for smoke detection is in 400.0-920.0 nm; for fire scar detection, it is suitable to select bands with central wavelengths of 900.0-930.0 and 1 300.0-2 400.0 nm, and then to combine them to construct a detection model.

  19. A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

    Directory of Open Access Journals (Sweden)

    He-Yuan Lin

    2008-03-01

    Full Text Available A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

  20. A Motion-Adaptive Deinterlacer via Hybrid Motion Detection and Edge-Pattern Recognition

    Directory of Open Access Journals (Sweden)

    Li Hsin-Te

    2008-01-01

    Full Text Available Abstract A novel motion-adaptive deinterlacing algorithm with edge-pattern recognition and hybrid motion detection is introduced. The great variety of video contents makes the processing of assorted motion, edges, textures, and the combination of them very difficult with a single algorithm. The edge-pattern recognition algorithm introduced in this paper exhibits the flexibility in processing both textures and edges which need to be separately accomplished by line average and edge-based line average before. Moreover, predicting the neighboring pixels for pattern analysis and interpolation further enhances the adaptability of the edge-pattern recognition unit when motion detection is incorporated. Our hybrid motion detection features accurate detection of fast and slow motion in interlaced video and also the motion with edges. Using only three fields for detection also renders higher temporal correlation for interpolation. The better performance of our deinterlacing algorithm with higher content-adaptability and less memory cost than the state-of-the-art 4-field motion detection algorithms can be seen from the subjective and objective experimental results of the CIF and PAL video sequences.

  1. Detection and spectral measurements of coherent synchrotron radiation at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Behrens, Christopher

    2010-02-15

    The operation of high-gain free-electron laser (FEL) underlies tremendous demands on high quality electron beams with high peak currents. At the Free-Electron-Laser in Hamburg (FLASH), two magnetic bunch compressors are used to compress the electron bunches longitudinally. In the bunch compressor magnets, these short electron bunches generate coherent synchrotron radiation (CSR). This CSR contains information on the longitudinal bunch profile, which is relevant for driving an FEL. In order to investigate coherent synchrotron radiation at the second bunch compressor BC3 at FLASH, a new setup behind the last dipole was installed. For the detection of coherent synchrotron radiation, which is emitted in the infrared regime, pyroelectric detectors were used. These pyroelectric detectors have been calibrated at the free-electron laser FELIX in the wavelength range from 5 {mu}m to 110 {mu}m. For characterisation of the emitted radiation, a transverse scanning device was used to measure the transverse intensity distribution. Various transmission filters were used to obtain additional information about the spectral content. In order to get spectral information with high resolution over a wide wavelength range, a rotating mirror spectrometer using reflective blazed gratings was installed. Using this spectrometer, the first spectral measurements of coherent synchrotron radiation at FLASH in a wavelength range from 10 {mu}m to 160 {mu}m were done. (orig.)

  2. Detection and spectral measurements of coherent synchrotron radiation at FLASH

    International Nuclear Information System (INIS)

    Behrens, Christopher

    2010-02-01

    The operation of high-gain free-electron laser (FEL) underlies tremendous demands on high quality electron beams with high peak currents. At the Free-Electron-Laser in Hamburg (FLASH), two magnetic bunch compressors are used to compress the electron bunches longitudinally. In the bunch compressor magnets, these short electron bunches generate coherent synchrotron radiation (CSR). This CSR contains information on the longitudinal bunch profile, which is relevant for driving an FEL. In order to investigate coherent synchrotron radiation at the second bunch compressor BC3 at FLASH, a new setup behind the last dipole was installed. For the detection of coherent synchrotron radiation, which is emitted in the infrared regime, pyroelectric detectors were used. These pyroelectric detectors have been calibrated at the free-electron laser FELIX in the wavelength range from 5 μm to 110 μm. For characterisation of the emitted radiation, a transverse scanning device was used to measure the transverse intensity distribution. Various transmission filters were used to obtain additional information about the spectral content. In order to get spectral information with high resolution over a wide wavelength range, a rotating mirror spectrometer using reflective blazed gratings was installed. Using this spectrometer, the first spectral measurements of coherent synchrotron radiation at FLASH in a wavelength range from 10 μm to 160 μm were done. (orig.)

  3. Edge Detection Based On the Characteristic of Primary Visual Cortex Cells

    Science.gov (United States)

    Zhu, M. M.; Xu, Y. L.; Ma, H. Q.

    2018-01-01

    Aiming at the problem that it is difficult to balance the accuracy of edge detection and anti-noise performance, and referring to the dynamic and static perceptions of the primary visual cortex (V1) cells, a V1 cell model is established to perform edge detection. A spatiotemporal filter is adopted to simulate the receptive field of V1 simple cells, the model V1 cell is obtained after integrating the responses of simple cells by half-wave rectification and normalization, Then the natural image edge is detected by using static perception of V1 cells. The simulation results show that, the V1 model can basically fit the biological data and has the universality of biology. What’s more, compared with other edge detection operators, the proposed model is more effective and has better robustness

  4. MEDICAL IMAGE COMPRESSION USING HYBRID CODER WITH FUZZY EDGE DETECTION

    Directory of Open Access Journals (Sweden)

    K. Vidhya

    2011-02-01

    Full Text Available Medical imaging techniques produce prohibitive amounts of digitized clinical data. Compression of medical images is a must due to large memory space required for transmission and storage. This paper presents an effective algorithm to compress and to reconstruct medical images. The proposed algorithm first extracts edge information of medical images by using fuzzy edge detector. The images are decomposed using Cohen-Daubechies-Feauveau (CDF wavelet. The hybrid technique utilizes the efficient wavelet based compression algorithms such as JPEG2000 and Set Partitioning In Hierarchical Trees (SPIHT. The wavelet coefficients in the approximation sub band are encoded using tier 1 part of JPEG2000. The wavelet coefficients in the detailed sub bands are encoded using SPIHT. Consistent quality images are produced by this method at a lower bit rate compared to other standard compression algorithms. Two main approaches to assess image quality are objective testing and subjective testing. The image quality is evaluated by objective quality measures. Objective measures correlate well with the perceived image quality for the proposed compression algorithm.

  5. Determination of edge plasma parameters by a genetic algorithm analysis of spectral line shapes

    International Nuclear Information System (INIS)

    Marandet, Y.; Genesio, P.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R.; Capes, H.; Guirlet, R.

    2003-01-01

    Comparing an experimental and a theoretical line shape can be achieved by a genetic algorithm (GA) based on an analogy to the mechanisms of natural selection. Such an algorithm is able to deal with complex non-linear models, and can avoid local minima. We have used this optimization tool in the context of edge plasma spectroscopy, for a determination of the temperatures and fractions of the various populations of neutral deuterium emitting the D α line in 2 configurations of Tore-Supra: ergodic divertor and toroidal pumped limiter. Using the GA fit, the neutral emitters are separated into up to 4 populations which can be identified as resulting from molecular dissociation reactions, charge exchange, or reflection. In all the edge plasmas studied, a significant fraction of neutrals emit in the line wings, leading to neutrals with a temperature up to a few hundreds eV if a Gaussian line shape is assumed. This conclusion could be modified if the line wing exhibits a non Gaussian behavior

  6. Determination of edge plasma parameters by a genetic algorithm analysis of spectral line shapes

    Energy Technology Data Exchange (ETDEWEB)

    Marandet, Y.; Genesio, P.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R. [Universite de Provence (PIIM), Centre de Saint-Jerome, 13 - Marseille (France); Capes, H.; Guirlet, R. [Association Euratom-CEA Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee

    2003-07-01

    Comparing an experimental and a theoretical line shape can be achieved by a genetic algorithm (GA) based on an analogy to the mechanisms of natural selection. Such an algorithm is able to deal with complex non-linear models, and can avoid local minima. We have used this optimization tool in the context of edge plasma spectroscopy, for a determination of the temperatures and fractions of the various populations of neutral deuterium emitting the D{sub {alpha}} line in 2 configurations of Tore-Supra: ergodic divertor and toroidal pumped limiter. Using the GA fit, the neutral emitters are separated into up to 4 populations which can be identified as resulting from molecular dissociation reactions, charge exchange, or reflection. In all the edge plasmas studied, a significant fraction of neutrals emit in the line wings, leading to neutrals with a temperature up to a few hundreds eV if a Gaussian line shape is assumed. This conclusion could be modified if the line wing exhibits a non Gaussian behavior.

  7. Eliminating the non-Gaussian spectral response of X-ray absorbers for transition-edge sensors

    Science.gov (United States)

    Yan, Daikang; Divan, Ralu; Gades, Lisa M.; Kenesei, Peter; Madden, Timothy J.; Miceli, Antonino; Park, Jun-Sang; Patel, Umeshkumar M.; Quaranta, Orlando; Sharma, Hemant; Bennett, Douglas A.; Doriese, William B.; Fowler, Joseph W.; Gard, Johnathon D.; Hays-Wehle, James P.; Morgan, Kelsey M.; Schmidt, Daniel R.; Swetz, Daniel S.; Ullom, Joel N.

    2017-11-01

    Transition-edge sensors (TESs) as microcalorimeters for high-energy-resolution X-ray spectroscopy are often fabricated with an absorber made of materials with high Z (for X-ray stopping power) and low heat capacity (for high resolving power). Bismuth represents one of the most compelling options. TESs with evaporated bismuth absorbers have shown spectra with undesirable and unexplained low-energy tails. We have developed TESs with electroplated bismuth absorbers over a gold layer that are not afflicted by this problem and that retain the other positive aspects of this material. To better understand these phenomena, we have studied a series of TESs with gold, gold/evaporated bismuth, and gold/electroplated bismuth absorbers, fabricated on the same die with identical thermal coupling. We show that the bismuth morphology is linked to the spectral response of X-ray TES microcalorimeters.

  8. Tools for spectral data analysis of arbitrary emitters in edge plasma

    International Nuclear Information System (INIS)

    Marandet, Y.; Genesio, P.; Godbert-Mouret, L.; Koubiti, M.; Stamm, R.; Felts, B.; Capes, H.; Guirlet, R.; Lotte, P.; Lowry, C.

    2003-01-01

    A line shape code including Stark, Zeeman and Doppler effects has been upgraded to include atomic fine structure effects and the motional Stark effect (MST). Genetic algorithms provide an efficient and robust tool for automated analysis of edge plasma line shapes. Such an algorithm has been used to fit Doppler-broadened Zeeman D α /H α spectra observed in Tore-Supra. Spectra were analyzed from 2 different machine configurations, corresponding to: 1) recycling from the ergodic divertor (ED), with lines of sight tangential to the magnetic field; 2) recycling at the toroidal pump limiter (TPL) with vertical lines of sight perpendicular to the magnetic field. Preliminary results indicate that the plasma above the TPL contains a larger fraction of warm particles than the ED plasma. (A.C.)

  9. New Spectral Index for Detecting Wheat Yellow Rust Using Sentinel-2 Multispectral Imagery

    Directory of Open Access Journals (Sweden)

    Qiong Zheng

    2018-03-01

    Full Text Available Yellow rust is one of the most destructive diseases for winter wheat and has led to a significant decrease in winter wheat quality and yield. Identifying and monitoring yellow rust is of great importance for guiding agricultural production over large areas. Compared with traditional crop disease discrimination methods, remote sensing technology has proven to be a useful tool for accomplishing such a task at large scale. This study explores the potential of the Sentinel-2 Multispectral Instrument (MSI, a newly launched satellite with refined spatial resolution and three red-edge bands, for discriminating between yellow rust infection severities (i.e., healthy, slight, and severe in winter wheat. The corresponding simulative multispectral bands for the Sentinel-2 sensor were calculated by the sensor’s relative spectral response (RSR function based on the in situ hyperspectral data acquired at the canopy level. Three Sentinel-2 spectral bands, including B4 (Red, B5 (Re1, and B7 (Re3, were found to be sensitive bands using the random forest (RF method. A new multispectral index, the Red Edge Disease Stress Index (REDSI, which consists of these sensitive bands, was proposed to detect yellow rust infection at different severity levels. The overall identification accuracy for REDSI was 84.1% and the kappa coefficient was 0.76. Moreover, REDSI performed better than other commonly used disease spectral indexes for yellow rust discrimination at the canopy scale. The optimal threshold method was adopted for mapping yellow rust infection at regional scales based on realistic Sentinel-2 multispectral image data to further assess REDSI’s ability for yellow rust detection. The overall accuracy was 85.2% and kappa coefficient was 0.67, which was found through validation against a set of field survey data. This study suggests that the Sentinel-2 MSI has the potential for yellow rust discrimination, and the newly proposed REDSI has great robustness and

  10. New Spectral Index for Detecting Wheat Yellow Rust Using Sentinel-2 Multispectral Imagery.

    Science.gov (United States)

    Zheng, Qiong; Huang, Wenjiang; Cui, Ximin; Shi, Yue; Liu, Linyi

    2018-03-15

    Yellow rust is one of the most destructive diseases for winter wheat and has led to a significant decrease in winter wheat quality and yield. Identifying and monitoring yellow rust is of great importance for guiding agricultural production over large areas. Compared with traditional crop disease discrimination methods, remote sensing technology has proven to be a useful tool for accomplishing such a task at large scale. This study explores the potential of the Sentinel-2 Multispectral Instrument (MSI), a newly launched satellite with refined spatial resolution and three red-edge bands, for discriminating between yellow rust infection severities (i.e., healthy, slight, and severe) in winter wheat. The corresponding simulative multispectral bands for the Sentinel-2 sensor were calculated by the sensor's relative spectral response (RSR) function based on the in situ hyperspectral data acquired at the canopy level. Three Sentinel-2 spectral bands, including B4 (Red), B5 (Re1), and B7 (Re3), were found to be sensitive bands using the random forest (RF) method. A new multispectral index, the Red Edge Disease Stress Index (REDSI), which consists of these sensitive bands, was proposed to detect yellow rust infection at different severity levels. The overall identification accuracy for REDSI was 84.1% and the kappa coefficient was 0.76. Moreover, REDSI performed better than other commonly used disease spectral indexes for yellow rust discrimination at the canopy scale. The optimal threshold method was adopted for mapping yellow rust infection at regional scales based on realistic Sentinel-2 multispectral image data to further assess REDSI's ability for yellow rust detection. The overall accuracy was 85.2% and kappa coefficient was 0.67, which was found through validation against a set of field survey data. This study suggests that the Sentinel-2 MSI has the potential for yellow rust discrimination, and the newly proposed REDSI has great robustness and generalized ability

  11. Novel method for edge detection of retinal vessels based on the model of the retinal vascular network and mathematical morphology

    Science.gov (United States)

    Xu, Lei; Zheng, Xiaoxiang; Zhang, Hengyi; Yu, Yajun

    1998-09-01

    Accurate edge detection of retinal vessels is a prerequisite for quantitative analysis of subtle morphological changes of retinal vessels under different pathological conditions. A novel method for edge detection of retinal vessels is presented in this paper. Methods: (1) Wavelet-based image preprocessing. (2) The signed edge detection algorithm and mathematical morphological operation are applied to get the approximate regions that contain retinal vessels. (3) By convolving the preprocessed image with a LoG operator only on the detected approximate regions of retinal vessels, followed by edges refining, clear edge maps of the retinal vessels are fast obtained. Results: A detailed performance evaluation together with the existing techniques is given to demonstrate the strong features of our method. Conclusions: True edge locations of retinal vessels can be fast detected with continuous structures of retinal vessels, less non- vessel segments left and insensitivity to noise. The method is also suitable for other application fields such as road edge detection.

  12. A robust sub-pixel edge detection method of infrared image based on tremor-based retinal receptive field model

    Science.gov (United States)

    Gao, Kun; Yang, Hu; Chen, Xiaomei; Ni, Guoqiang

    2008-03-01

    Because of complex thermal objects in an infrared image, the prevalent image edge detection operators are often suitable for a certain scene and extract too wide edges sometimes. From a biological point of view, the image edge detection operators work reliably when assuming a convolution-based receptive field architecture. A DoG (Difference-of- Gaussians) model filter based on ON-center retinal ganglion cell receptive field architecture with artificial eye tremors introduced is proposed for the image contour detection. Aiming at the blurred edges of an infrared image, the subsequent orthogonal polynomial interpolation and sub-pixel level edge detection in rough edge pixel neighborhood is adopted to locate the foregoing rough edges in sub-pixel level. Numerical simulations show that this method can locate the target edge accurately and robustly.

  13. In-vitro studies of change in edge detection with changes in bone density

    International Nuclear Information System (INIS)

    Pocock, N.; Noakes, K.; Griffiths, M.

    1999-01-01

    Full text: Dual energy X-ray absorptiometry (DXA) requires edge detection software to identify the skeletal regions for quantitation of bone mineral density (BMD) and bone mineral content (BMC). As bone mass decreases, the detection of bone edges becomes more difficult and this potentially could cause errors in DXA estimations of areal BMD or BMC. To address this issue, we have used an in-vitro model to study the effects of 'bone loss' on calculated bone area, BMD and BMC. Multiple vertebral phantoms, of equal cross-sectional area but incrementally decreased areal BMD, were constructed using calcium sulphate hemihydrate. The weight of each phantom vertebra, measured accurately using an electronic balance, was used as an index of its true 'bone mass equivalent' (BME). The phantoms were scanned and analysed in the lumbar spine mode using a Lunar DPX-L (L) and Hologic QDR-1000 (H). The changes in BME were compared to changes in measured area, BMC and areal BMD. The results demonstrate that, in an in-vitro model, as bone mass decreases, measured bone area and consequently BMC will decrease as the edge detection algorithms have greater difficulty in detecting the true edges. In conclusion, in an in-vitro model, the DXA edge detection algorithms will underestimate bone area as bone mass decreases. This has potential implications for monitoring changes in bone mass in vivo

  14. Edge detection and mathematic fitting for corneal surface with Matlab software.

    Science.gov (United States)

    Di, Yue; Li, Mei-Yan; Qiao, Tong; Lu, Na

    2017-01-01

    To select the optimal edge detection methods to identify the corneal surface, and compare three fitting curve equations with Matlab software. Fifteen subjects were recruited. The corneal images from optical coherence tomography (OCT) were imported into Matlab software. Five edge detection methods (Canny, Log, Prewitt, Roberts, Sobel) were used to identify the corneal surface. Then two manual identifying methods (ginput and getpts) were applied to identify the edge coordinates respectively. The differences among these methods were compared. Binomial curve (y=Ax 2 +Bx+C), Polynomial curve [p(x)=p1x n +p2x n-1 +....+pnx+pn+1] and Conic section (Ax 2 +Bxy+Cy 2 +Dx+Ey+F=0) were used for curve fitting the corneal surface respectively. The relative merits among three fitting curves were analyzed. Finally, the eccentricity (e) obtained by corneal topography and conic section were compared with paired t -test. Five edge detection algorithms all had continuous coordinates which indicated the edge of the corneal surface. The ordinates of manual identifying were close to the inside of the actual edges. Binomial curve was greatly affected by tilt angle. Polynomial curve was lack of geometrical properties and unstable. Conic section could calculate the tilted symmetry axis, eccentricity, circle center, etc . There were no significant differences between 'e' values by corneal topography and conic section ( t =0.9143, P =0.3760 >0.05). It is feasible to simulate the corneal surface with mathematical curve with Matlab software. Edge detection has better repeatability and higher efficiency. The manual identifying approach is an indispensable complement for detection. Polynomial and conic section are both the alternative methods for corneal curve fitting. Conic curve was the optimal choice based on the specific geometrical properties.

  15. Heterodyne detection using spectral line pairing for spectral phase encoding optical code division multiple access and dynamic dispersion compensation.

    Science.gov (United States)

    Yang, Yi; Foster, Mark; Khurgin, Jacob B; Cooper, A Brinton

    2012-07-30

    A novel coherent optical code-division multiple access (OCDMA) scheme is proposed that uses spectral line pairing to generate signals suitable for heterodyne decoding. Both signal and local reference are transmitted via a single optical fiber and a simple balanced receiver performs sourceless heterodyne detection, canceling speckle noise and multiple-access interference (MAI). To validate the idea, a 16 user fully loaded phase encoded system is simulated. Effects of fiber dispersion on system performance are studied as well. Both second and third order dispersion management is achieved by using a spectral phase encoder to adjust phase shifts of spectral components at the optical network unit (ONU).

  16. Comparing auditory filter bandwidths, spectral ripple modulation detection, spectral ripple discrimination, and speech recognition: Normal and impaired hearing.

    Science.gov (United States)

    Davies-Venn, Evelyn; Nelson, Peggy; Souza, Pamela

    2015-07-01

    Some listeners with hearing loss show poor speech recognition scores in spite of using amplification that optimizes audibility. Beyond audibility, studies have suggested that suprathreshold abilities such as spectral and temporal processing may explain differences in amplified speech recognition scores. A variety of different methods has been used to measure spectral processing. However, the relationship between spectral processing and speech recognition is still inconclusive. This study evaluated the relationship between spectral processing and speech recognition in listeners with normal hearing and with hearing loss. Narrowband spectral resolution was assessed using auditory filter bandwidths estimated from simultaneous notched-noise masking. Broadband spectral processing was measured using the spectral ripple discrimination (SRD) task and the spectral ripple depth detection (SMD) task. Three different measures were used to assess unamplified and amplified speech recognition in quiet and noise. Stepwise multiple linear regression revealed that SMD at 2.0 cycles per octave (cpo) significantly predicted speech scores for amplified and unamplified speech in quiet and noise. Commonality analyses revealed that SMD at 2.0 cpo combined with SRD and equivalent rectangular bandwidth measures to explain most of the variance captured by the regression model. Results suggest that SMD and SRD may be promising clinical tools for diagnostic evaluation and predicting amplification outcomes.

  17. Comparing auditory filter bandwidths, spectral ripple modulation detection, spectral ripple discrimination, and speech recognition: Normal and impaired hearinga)

    Science.gov (United States)

    Davies-Venn, Evelyn; Nelson, Peggy; Souza, Pamela

    2015-01-01

    Some listeners with hearing loss show poor speech recognition scores in spite of using amplification that optimizes audibility. Beyond audibility, studies have suggested that suprathreshold abilities such as spectral and temporal processing may explain differences in amplified speech recognition scores. A variety of different methods has been used to measure spectral processing. However, the relationship between spectral processing and speech recognition is still inconclusive. This study evaluated the relationship between spectral processing and speech recognition in listeners with normal hearing and with hearing loss. Narrowband spectral resolution was assessed using auditory filter bandwidths estimated from simultaneous notched-noise masking. Broadband spectral processing was measured using the spectral ripple discrimination (SRD) task and the spectral ripple depth detection (SMD) task. Three different measures were used to assess unamplified and amplified speech recognition in quiet and noise. Stepwise multiple linear regression revealed that SMD at 2.0 cycles per octave (cpo) significantly predicted speech scores for amplified and unamplified speech in quiet and noise. Commonality analyses revealed that SMD at 2.0 cpo combined with SRD and equivalent rectangular bandwidth measures to explain most of the variance captured by the regression model. Results suggest that SMD and SRD may be promising clinical tools for diagnostic evaluation and predicting amplification outcomes. PMID:26233047

  18. Edge detection of optical subaperture image based on improved differential box-counting method

    Science.gov (United States)

    Li, Yi; Hui, Mei; Liu, Ming; Dong, Liquan; Kong, Lingqin; Zhao, Yuejin

    2018-01-01

    Optical synthetic aperture imaging technology is an effective approach to improve imaging resolution. Compared with monolithic mirror system, the image of optical synthetic aperture system is often more complex at the edge, and as a result of the existence of gap between segments, which makes stitching becomes a difficult problem. So it is necessary to extract the edge of subaperture image for achieving effective stitching. Fractal dimension as a measure feature can describe image surface texture characteristics, which provides a new approach for edge detection. In our research, an improved differential box-counting method is used to calculate fractal dimension of image, then the obtained fractal dimension is mapped to grayscale image to detect edges. Compared with original differential box-counting method, this method has two improvements as follows: by modifying the box-counting mechanism, a box with a fixed height is replaced by a box with adaptive height, which solves the problem of over-counting the number of boxes covering image intensity surface; an image reconstruction method based on super-resolution convolutional neural network is used to enlarge small size image, which can solve the problem that fractal dimension can't be calculated accurately under the small size image, and this method may well maintain scale invariability of fractal dimension. The experimental results show that the proposed algorithm can effectively eliminate noise and has a lower false detection rate compared with the traditional edge detection algorithms. In addition, this algorithm can maintain the integrity and continuity of image edge in the case of retaining important edge information.

  19. EDGE DETECTION OF THE SCOLIOTIC VERTEBRAE USING X-RAY IMAGES

    Directory of Open Access Journals (Sweden)

    P. MOHANKUMAR

    2016-02-01

    Full Text Available Bones act as a mineral storage reservoir for calcium and phosphorus. Proper well grown bones give a perfect posture to the human body. In other case, if the bone has an improper growth, it might lead to an abnormal posture or an awkward posture. Scoliosis is a condition where the scoliotic vertebrae are wedge shaped and differ with the shape of normal vertebrae. Treatment for scoliosis depends on Cobb angle which can be measured using spine X-rays. Recent development in the medical imaging techniques brought us to a new research area in image processing which includes medical image enhancement, detailed visualization of internal organs & tissues and edge detection. Bone edges are important feature in an X-ray image. The purpose of application of segmentation in medical imaging is to develop a detailed framework on human anatomy, whose primary objective is to outline the anatomical structures. Whereas edge detection is a technique which extracts vital features like corners, lines, angles and curves from an image. In this study, we are going to deal with the edge detection technique on scoliotic vertebrae. The objective of this paper is to compare the performance of edge detectors using filters and operators.

  20. Exploiting Affine Invariant Regions and Leaf Edge Shapes for Weed Detection

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Ruiz, Francisco Garcia; Nielsen, Jon

    2015-01-01

    . Then a comparison with the field data retrieval highlighted the trade-off due to the field challenges. Adopting a comprehensive approach, edge shape detectors and homogeneous surface detecting affine invariant regions were fused. In order to integrate vegetation indices as local features, a new local vegetation...

  1. Pollution detection using the spectral fluorescent signatures (SFS technique

    Directory of Open Access Journals (Sweden)

    Mª Del Carmen Martín

    2014-06-01

    Full Text Available This work has been developed in the Applied Physics Department at the University of Vigo within the line of research based on the treatment of the degraded water by pollutants through the use of microalgae, reducing the emissions of greenhouse gases through the absorption of CO2 in the process and the reuse of biomass as biofuel. Remote sensing techniques have contributed to a great extent to the development of oil pollution monitoring systems. However, the available detection methods, mainly designed for spaceborne and airborne long distance inspection, are too expensive and complex to be used in an operational way by relatively unskilled personnel. In the framework of DEOSOM project (European AMPERA project, an innovative water monitoring method was proposed, in two steps: early oil spill detection using a portable shipborne laser-induced fluorescence LIDAR (LIF/LIDAR, and analysis of suspicious water samples in laboratory using the Spectral Fluorescent Signature (SFS technique. This work is focused on the second technique. This system aims to optimize the production of microalgae for biofuel and contaminant cleaning applications and was developed and tested in photo-bioreactors in the University of Vigo within the EnerBioAlgae project (SUDOE. In this project, the SFS technique was used as a diagnostic tool employing the fluorescence analyzer INSTANT-SCREENER M53UVC. The Spectral Fluorescence Signature technique (SFS is based on compounds fluorescence properties. The fluorescence intensity of a sample is measured at different excitation and emission wavelengths to produce a 3-dimensional fluorescence matrix, which can also be presented as a 2-dimensional color image where the color shows the intensity of the fluorescence. These matrices offer qualitative and quantitative information, since they can be useful for the identification of different substances from their characteristic excitation and emission spectra of fluorescence. They also

  2. COHERENT DETECTION FOR SPECTRAL AMPLITUDE-CODED OPTICAL LABEL SWITCHING SYSTEMS

    DEFF Research Database (Denmark)

    Osadchiy, Alexey Vladimirovich; Tafur Monroy, Idelfonso

    2010-01-01

    Coherent detection for spectrally encoded optical labels is proposed and experimentally demonstrated for three label tones spectrally spaced at 1 GHz. The proposed method utilizes a frequency swept local oscillator in a coherent receiver supported by digital signal processing for improved...... flexibility and upgradeability while reducing label detection subsystem complexity as compared with the conventional optical autocorrelation based approaches....

  3. Prostate Cancer Detection Using Near Infrared Spectral Polarization Imaging

    National Research Council Canada - National Science Library

    Alfano, R. R; Wang, W. B

    2005-01-01

    .... The technique is based on the spectral and polarization properties of light scattered, absorbed and emitted from prostate cancerous and normal tissues, and contrast agents targeted to the prostate cancers. Results of finding...

  4. Edge-based correlation image registration for multispectral imaging

    Science.gov (United States)

    Nandy, Prabal [Albuquerque, NM

    2009-11-17

    Registration information for images of a common target obtained from a plurality of different spectral bands can be obtained by combining edge detection and phase correlation. The images are edge-filtered, and pairs of the edge-filtered images are then phase correlated to produce phase correlation images. The registration information can be determined based on these phase correlation images.

  5. Implementing a Parallel Image Edge Detection Algorithm Based on the Otsu-Canny Operator on the Hadoop Platform.

    Science.gov (United States)

    Cao, Jianfang; Chen, Lichao; Wang, Min; Tian, Yun

    2018-01-01

    The Canny operator is widely used to detect edges in images. However, as the size of the image dataset increases, the edge detection performance of the Canny operator decreases and its runtime becomes excessive. To improve the runtime and edge detection performance of the Canny operator, in this paper, we propose a parallel design and implementation for an Otsu-optimized Canny operator using a MapReduce parallel programming model that runs on the Hadoop platform. The Otsu algorithm is used to optimize the Canny operator's dual threshold and improve the edge detection performance, while the MapReduce parallel programming model facilitates parallel processing for the Canny operator to solve the processing speed and communication cost problems that occur when the Canny edge detection algorithm is applied to big data. For the experiments, we constructed datasets of different scales from the Pascal VOC2012 image database. The proposed parallel Otsu-Canny edge detection algorithm performs better than other traditional edge detection algorithms. The parallel approach reduced the running time by approximately 67.2% on a Hadoop cluster architecture consisting of 5 nodes with a dataset of 60,000 images. Overall, our approach system speeds up the system by approximately 3.4 times when processing large-scale datasets, which demonstrates the obvious superiority of our method. The proposed algorithm in this study demonstrates both better edge detection performance and improved time performance.

  6. Edge detection of barium-filled stomach picture by one-dimensional collation method

    International Nuclear Information System (INIS)

    Nakamura, Shizuo

    1983-01-01

    The method for the contour edge detection of barium- filled stomach pictures by X-ray for the automatic screening is described using computer technique. It is necessary for the automatic screening of barium- filling pictures to detect accurately the outline of stomachs because the analysis of repletion pictures is performed by checking the disorder of marginal contours and abnormal stomach shapes. However, the detection of the coutour lines is difficult to be successful for the reason that the contrast of stomach pictures to background is low, a stomach is not necessarily filled completely with barium and the shadow of barium flowing into intestines is superimposed on stomach images and the shading is likely to occur. The engineering processing against these problems is not yet solved. In order to reduce the noise due to differential operator, the proposed method determines the boundary of a thing generally by the threshold value of density, and defines the edge of the thing from the differential waveform of density in the vicinity of the boundary. In addition, the method corrects the detection error caused by the local nonconformity of parameters by comparing the edges between the adjacent lines. As a result, in spite of its simple algorithm, the edges with good continuity and less noise can be detected, and the method is not much affected by shading. This method was found to be applicable to the images of others than stomachs. The extraction of the contour of barium- filling pictures requires the high level recognition processing instead of the simple conditioning. (Wakatsuki, Y.)

  7. Adjustment of Sentinel-2 Multi-Spectral Instrument (MSI Red-Edge Band Reflectance to Nadir BRDF Adjusted Reflectance (NBAR and Quantification of Red-Edge Band BRDF Effects

    Directory of Open Access Journals (Sweden)

    David P. Roy

    2017-12-01

    Full Text Available Optical wavelength satellite data have directional reflectance effects over non-Lambertian surfaces, described by the bidirectional reflectance distribution function (BRDF. The Sentinel-2 multi-spectral instrument (MSI acquires data over a 20.6° field of view that have been shown to have non-negligible BRDF effects in the visible, near-infrared, and short wave infrared bands. MSI red-edge BRDF effects have not been investigated. In this study, they are quantified by an examination of 6.6 million (January 2016 and 10.7 million (April 2016 pairs of forward and back scatter reflectance observations extracted over approximately 20° × 10° of southern Africa. Non-negligible MSI red-edge BRDF effects up to 0.08 (reflectance units across the 290 km wide MSI swath are documented. A recently published MODIS BRDF parameter c-factor approach to adjust MSI visible, near-infrared, and short wave infrared reflectance to nadir BRDF-adjusted reflectance (NBAR is adapted for application to the MSI red-edge bands. The red-edge band BRDF parameters needed to implement the algorithm are provided. The parameters are derived by a linear wavelength interpolation of fixed global MODIS red and NIR BRDF model parameters. The efficacy of the interpolation is investigated using POLDER red, red-edge, and NIR BRDF model parameters, and is shown to be appropriate for the c-factor NBAR generation approach. After adjustment to NBAR, red-edge MSI BRDF effects were reduced for the January data (acquired close to the solar principal where BRDF effects are maximal and the April data (acquired close to the orthogonal plane for all the MSI red-edge bands.

  8. The Relationship Between Spectral Modulation Detection and Speech Recognition: Adult Versus Pediatric Cochlear Implant Recipients.

    Science.gov (United States)

    Gifford, René H; Noble, Jack H; Camarata, Stephen M; Sunderhaus, Linsey W; Dwyer, Robert T; Dawant, Benoit M; Dietrich, Mary S; Labadie, Robert F

    2018-01-01

    Adult cochlear implant (CI) recipients demonstrate a reliable relationship between spectral modulation detection and speech understanding. Prior studies documenting this relationship have focused on postlingually deafened adult CI recipients-leaving an open question regarding the relationship between spectral resolution and speech understanding for adults and children with prelingual onset of deafness. Here, we report CI performance on the measures of speech recognition and spectral modulation detection for 578 CI recipients including 477 postlingual adults, 65 prelingual adults, and 36 prelingual pediatric CI users. The results demonstrated a significant correlation between spectral modulation detection and various measures of speech understanding for 542 adult CI recipients. For 36 pediatric CI recipients, however, there was no significant correlation between spectral modulation detection and speech understanding in quiet or in noise nor was spectral modulation detection significantly correlated with listener age or age at implantation. These findings suggest that pediatric CI recipients might not depend upon spectral resolution for speech understanding in the same manner as adult CI recipients. It is possible that pediatric CI users are making use of different cues, such as those contained within the temporal envelope, to achieve high levels of speech understanding. Further investigation is warranted to investigate the relationship between spectral and temporal resolution and speech recognition to describe the underlying mechanisms driving peripheral auditory processing in pediatric CI users.

  9. Wavelet based edge detection algorithm for web surface inspection of coated board web

    Energy Technology Data Exchange (ETDEWEB)

    Barjaktarovic, M; Petricevic, S, E-mail: slobodan@etf.bg.ac.r [School of Electrical Engineering, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia)

    2010-07-15

    This paper presents significant improvement of the already installed vision system. System was designed for real time coated board inspection. The improvement is achieved with development of a new algorithm for edge detection. The algorithm is based on the redundant (undecimated) wavelet transform. Compared to the existing algorithm better delineation of edges is achieved. This yields to better defect detection probability and more accurate geometrical classification, which will provide additional reduction of waste. Also, algorithm will provide detailed classification and more reliably tracking of defects. This improvement requires minimal changes in processing hardware, only a replacement of the graphic card would be needed, adding only negligibly to the system cost. Other changes are accomplished entirely in the image processing software.

  10. Edge detection of iris of the eye for human biometric identification system

    Directory of Open Access Journals (Sweden)

    Kateryna O. Tryfonova

    2015-03-01

    Full Text Available Method of human biometric identification by iris of the eye is considered as one of the most accurate and reliable methods of identification. Aim of the research is to solve the problem of edge detection of digital image of the human eye iris to be able to implement human biometric identification system by means of mobile device. To achieve this aim the algorithm of edge detection by Canny is considered in work. It consists of the following steps: smoothing, finding gradients, non-maximum suppression, double thresholding with hysteresis. The software implementation of the Canny algorithm is carried out for the Android mobile platform with the use of high level programming language Java.

  11. A Trajectory Generation Method Based on Edge Detection for Auto-Sealant Cartesian Robot

    Directory of Open Access Journals (Sweden)

    Eka Samsul Maarif

    2014-07-01

    Full Text Available This paper presents algorithm ingenerating trajectory for sealant process using captured image. Cartesian robot as auto-sealant in manufacturing process has increased productivity, reduces human error and saves time. But, different sealant path in many engine models means not only different trajectory but also different program. Therefore robot with detection ability to generate its own trajectory is needed. This paper describes best lighting technique in capturing image and applies edge detection in trajectory generation as the solution. The algorithm comprises image capturing, Canny edge detection, integral projection in localizing outer most edge, scanning coordinates, and generating vector direction codes. The experiment results show that the best technique is diffuse lighting at 10 Cd. The developed method gives connected point to point trajectory which forms sealant path with a point to next point distance is equal to 90° motor rotation. Directional movement for point to point trajectory is controlled by generated codes which are ready to be sent by serial communication to robot controller as instruction for motors which actuate axes X and Y directions.

  12. Detection Performance of Packet Arrival under Downclocking for Mobile Edge Computing

    Directory of Open Access Journals (Sweden)

    Zhimin Wang

    2018-01-01

    Full Text Available Mobile edge computing (MEC enables battery-powered mobile nodes to acquire information technology services at the network edge. These nodes desire to enjoy their service under power saving. The sampling rate invariant detection (SRID is the first downclocking WiFi technique that can achieve this objective. With SRID, a node detects one packet arrival at a downclocked rate. Upon a successful detection, the node reverts to a full-clocked rate to receive the packet immediately. To ensure that a node acquires its service immediately, the detection performance (namely, the miss-detection probability and the false-alarm probability of SRID is of importance. This paper is the first one to theoretically study the crucial impact of SRID attributes (e.g., tolerance threshold, correlation threshold, and energy ratio threshold on the packet detection performance. Extensive Monte Carlo experiments show that our theoretical model is very accurate. This study can help system developers set reasonable system parameters for WiFi downclocking.

  13. Vehicle detection based on the use of shadow region and edge

    Science.gov (United States)

    Jeong, Sangheon; Kang, Seongkoo; Kim, Joongkyu

    2013-07-01

    Automotive and advanced driver assistance systems have attracted a great deal of attention lately. In these systems, effective and reliable vehicle detection is important because such systems can reduce the number of accidents and save human' lives. This paper describes an approach to detecting a forward vehicle using a camera mounted on the moving vehicle. In this paper, we describe two methods to detect a vehicle on the road. First, by using the vehicle's shadow, we can obtain the general location of the vehicular candidate. Second, we can identify the strong vertical edges at the left and right position of a vehicle. By combining the shadows and the edge, we can detect the vehicle's location. But other regions may also be detected, such as car windows, reflections, and illumination by the sun. In order to remove these other factors, defined as noises, we need to use a filter. After using the filter, we can calculate the exact location of the vehicle. Additionally, by using connected component labeling, we can obtain coordinates and establish the vehicle's location. Connected component labeling find all connected components in an image and assigns a unique label to all points in the same component. These methods are very useful for vehicle detection and the development of the driving assistance systems, and they can protect drivers' safety from having an accident.

  14. The properties of ITE's silicon avalanche photodiodes within the spectral range used in scintillation detection

    CERN Document Server

    Wegrzecka, I

    1999-01-01

    The design and properties of 3 mm silicon avalanche photodiodes developed at ITE are presented. Their performance parameters within the spectral range applicable in scintillation detection (400-700 nm) are discussed and compared to those for near infrared radiation.

  15. The properties of ITE's silicon avalanche photodiodes within the spectral range used in scintillation detection

    Science.gov (United States)

    Wegrzecka, Iwona; Wegrzecki, Maciej

    1999-04-01

    The design and properties of 3 mm silicon avalanche photodiodes developed at ITE are presented. Their performance parameters within the spectral range applicable in scintillation detection (400-700 nm) are discussed and compared to those for near infrared radiation.

  16. Power Load Event Detection and Classification Based on Edge Symbol Analysis and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Lei Jiang

    2012-01-01

    Full Text Available Energy signature analysis of power appliance is the core of nonintrusive load monitoring (NILM where the detailed data of the appliances used in houses are obtained by analyzing changes in the voltage and current. This paper focuses on developing an automatic power load event detection and appliance classification based on machine learning. In power load event detection, the paper presents a new transient detection algorithm. By turn-on and turn-off transient waveforms analysis, it can accurately detect the edge point when a device is switched on or switched off. The proposed load classification technique can identify different power appliances with improved recognition accuracy and computational speed. The load classification method is composed of two processes including frequency feature analysis and support vector machine. The experimental results indicated that the incorporation of the new edge detection and turn-on and turn-off transient signature analysis into NILM revealed more information than traditional NILM methods. The load classification method has achieved more than ninety percent recognition rate.

  17. Comparison of Bayesian clustering and edge detection methods for inferring boundaries in landscape genetics

    Science.gov (United States)

    Safner, T.; Miller, M.P.; McRae, B.H.; Fortin, M.-J.; Manel, S.

    2011-01-01

    Recently, techniques available for identifying clusters of individuals or boundaries between clusters using genetic data from natural populations have expanded rapidly. Consequently, there is a need to evaluate these different techniques. We used spatially-explicit simulation models to compare three spatial Bayesian clustering programs and two edge detection methods. Spatially-structured populations were simulated where a continuous population was subdivided by barriers. We evaluated the ability of each method to correctly identify boundary locations while varying: (i) time after divergence, (ii) strength of isolation by distance, (iii) level of genetic diversity, and (iv) amount of gene flow across barriers. To further evaluate the methods' effectiveness to detect genetic clusters in natural populations, we used previously published data on North American pumas and a European shrub. Our results show that with simulated and empirical data, the Bayesian spatial clustering algorithms outperformed direct edge detection methods. All methods incorrectly detected boundaries in the presence of strong patterns of isolation by distance. Based on this finding, we support the application of Bayesian spatial clustering algorithms for boundary detection in empirical datasets, with necessary tests for the influence of isolation by distance. ?? 2011 by the authors; licensee MDPI, Basel, Switzerland.

  18. Sensitive detection of aerosol effect on simulated IASI spectral radiance

    International Nuclear Information System (INIS)

    Quan, X.; Huang, H.-L.; Zhang, L.; Weisz, E.; Cao, X.

    2013-01-01

    Guided by radiative transfer modeling of the effects of dust (aerosol) on satellite thermal infrared radiance by many different imaging radiometers, in this article, we present the aerosol-effected satellite radiative signal changes in the top of atmosphere (TOA). The simulation of TOA radiance for Infrared Atmospheric Sounding Interferometer (IASI) is performed by using the RTTOV fast radiative transfer model. The model computation is carried out with setting representative geographical atmospheric models and typical default aerosol climatological models under clear sky condition. The radiative differences (in units of equivalent black body brightness temperature differences (BTDs)) between simulated radiances without consideration of the impact of aerosol (Aerosol-free) and with various aerosol models (Aerosol-modified) are calculated for the whole IASI spectrum between 3.62 and 15.5 μm. The comparisons of BTDs are performed through 11 aerosol models in 5 classified atmospheric models. The results show that the Desert aerosol model has the most significant impact on IASI spectral simulated radiances than the other aerosol models (Continental, Urban, Maritime types and so on) in Mid-latitude Summer, contributing to the mineral aerosol components contained. The value of BTDs could reach up to 1 K at peak points. The atmospheric window spectral region between 900 and 1100 cm −1 (9.09–11.11 μm) is concentrated after the investigation for the largest values of aerosol-affected radiance differences. BTDs in IASI spectral region between 645 and 1200 cm −1 occupies the largest oscillation and the major part of the whole spectrum. The IASI highest window peak-points channels (such as 9.4 and 10.2 μm) are obtained finally, which are the most sensitive ones to the simulated IASI radiance. -- Highlights: ► Sensitive study of aerosol effect on simulated IASI spectral radiance is performed. ► The aerosol components have influenced IASI spectral regions

  19. Fast Edge Detection and Segmentation of Terrestrial Laser Scans Through Normal Variation Analysis

    Science.gov (United States)

    Che, E.; Olsen, M. J.

    2017-09-01

    Terrestrial Laser Scanning (TLS) utilizes light detection and ranging (lidar) to effectively and efficiently acquire point cloud data for a wide variety of applications. Segmentation is a common procedure of post-processing to group the point cloud into a number of clusters to simplify the data for the sequential modelling and analysis needed for most applications. This paper presents a novel method to rapidly segment TLS data based on edge detection and region growing. First, by computing the projected incidence angles and performing the normal variation analysis, the silhouette edges and intersection edges are separated from the smooth surfaces. Then a modified region growing algorithm groups the points lying on the same smooth surface. The proposed method efficiently exploits the gridded scan pattern utilized during acquisition of TLS data from most sensors and takes advantage of parallel programming to process approximately 1 million points per second. Moreover, the proposed segmentation does not require estimation of the normal at each point, which limits the errors in normal estimation propagating to segmentation. Both an indoor and outdoor scene are used for an experiment to demonstrate and discuss the effectiveness and robustness of the proposed segmentation method.

  20. Adjustment of Sentinel-2 Multi-Spectral Instrument (MSI) Red-Edge Band Reflectance to Nadir BRDF Adjusted Reflectance (NBAR) and Quantification of Red-Edge Band BRDF Effects

    OpenAIRE

    David P. Roy; Zhongbin Li; Hankui K. Zhang

    2017-01-01

    Optical wavelength satellite data have directional reflectance effects over non-Lambertian surfaces, described by the bidirectional reflectance distribution function (BRDF). The Sentinel-2 multi-spectral instrument (MSI) acquires data over a 20.6° field of view that have been shown to have non-negligible BRDF effects in the visible, near-infrared, and short wave infrared bands. MSI red-edge BRDF effects have not been investigated. In this study, they are quantified by an examination of 6.6 mi...

  1. Comparing Broad-Band and Red Edge-Based Spectral Vegetation Indices to Estimate Nitrogen Concentration of Crops Using Casi Data

    Science.gov (United States)

    Wang, Yanjie; Liao, Qinhong; Yang, Guijun; Feng, Haikuan; Yang, Xiaodong; Yue, Jibo

    2016-06-01

    In recent decades, many spectral vegetation indices (SVIs) have been proposed to estimate the leaf nitrogen concentration (LNC) of crops. However, most of these indices were based on the field hyperspectral reflectance. To test whether they can be used in aerial remote platform effectively, in this work a comparison of the sensitivity between several broad-band and red edge-based SVIs to LNC is investigated over different crop types. By using data from experimental LNC values over 4 different crop types and image data acquired using the Compact Airborne Spectrographic Imager (CASI) sensor, the extensive dataset allowed us to evaluate broad-band and red edge-based SVIs. The result indicated that NDVI performed the best among the selected SVIs while red edge-based SVIs didn't show the potential for estimating the LNC based on the CASI data due to the spectral resolution. In order to search for the optimal SVIs, the band combination algorithm has been used in this work. The best linear correlation against the experimental LNC dataset was obtained by combining the 626.20nm and 569.00nm wavebands. These wavelengths correspond to the maximal chlorophyll absorption and reflection position region, respectively, and are known to be sensitive to the physiological status of the plant. Then this linear relationship was applied to the CASI image for generating an LNC map, which can guide farmers in the accurate application of their N fertilization strategies.

  2. Optical detection of explosives: spectral signatures for the explosive bouquet

    Science.gov (United States)

    Osborn, Tabetha; Kaimal, Sindhu; Causey, Jason; Burns, William; Reeve, Scott

    2009-05-01

    Research with canines suggests that sniffer dogs alert not on the odor from a pure explosive, but rather on a set of far more volatile species present in an explosive as impurities. Following the explosive trained canine example, we have begun examining the vapor signatures for many of these volatile impurities utilizing high resolution spectroscopic techniques in several molecular fingerprint regions. Here we will describe some of these high resolution measurements and discuss strategies for selecting useful spectral signature regions for individual molecular markers of interest.

  3. Robust and fast license plate detection based on the fusion of color and edge feature

    Science.gov (United States)

    Cai, De; Shi, Zhonghan; Liu, Jin; Hu, Chuanping; Mei, Lin; Qi, Li

    2014-11-01

    Extracting a license plate is an important stage in automatic vehicle identification. The degradation of images and the computation intense make this task difficult. In this paper, a robust and fast license plate detection based on the fusion of color and edge feature is proposed. Based on the dichromatic reflection model, two new color ratios computed from the RGB color model are introduced and proved to be two color invariants. The global color feature extracted by the new color invariants improves the method's robustness. The local Sobel edge feature guarantees the method's accuracy. In the experiment, the detection performance is good. The detection results show that this paper's method is robust to the illumination, object geometry and the disturbance around the license plates. The method can also detect license plates when the color of the car body is the same as the color of the plates. The processing time for image size of 1000x1000 by pixels is nearly 0.2s. Based on the comparison, the performance of the new ratios is comparable to the common used HSI color model.

  4. Spectrally optimal illuminations for diabetic retinopathy detection in retinal imaging

    Science.gov (United States)

    Bartczak, Piotr; Fält, Pauli; Penttinen, Niko; Ylitepsa, Pasi; Laaksonen, Lauri; Lensu, Lasse; Hauta-Kasari, Markku; Uusitalo, Hannu

    2017-04-01

    Retinal photography is a standard method for recording retinal diseases for subsequent analysis and diagnosis. However, the currently used white light or red-free retinal imaging does not necessarily provide the best possible visibility of different types of retinal lesions, important when developing diagnostic tools for handheld devices, such as smartphones. Using specifically designed illumination, the visibility and contrast of retinal lesions could be improved. In this study, spectrally optimal illuminations for diabetic retinopathy lesion visualization are implemented using a spectrally tunable light source based on digital micromirror device. The applicability of this method was tested in vivo by taking retinal monochrome images from the eyes of five diabetic volunteers and two non-diabetic control subjects. For comparison to existing methods, we evaluated the contrast of retinal images taken with our method and red-free illumination. The preliminary results show that the use of optimal illuminations improved the contrast of diabetic lesions in retinal images by 30-70%, compared to the traditional red-free illumination imaging.

  5. The detection of 'virtual' objects using echoes by humans: Spectral cues.

    Science.gov (United States)

    Rowan, Daniel; Papadopoulos, Timos; Archer, Lauren; Goodhew, Amanda; Cozens, Hayley; Lopez, Ricardo Guzman; Edwards, David; Holmes, Hannah; Allen, Robert

    2017-07-01

    Some blind people use echoes to detect discrete, silent objects to support their spatial orientation/navigation, independence, safety and wellbeing. The acoustical features that people use for this are not well understood. Listening to changes in spectral shape due to the presence of an object could be important for object detection and avoidance, especially at short range, although it is currently not known whether it is possible with echolocation-related sounds. Bands of noise were convolved with recordings of binaural impulse responses of objects in an anechoic chamber to create 'virtual objects', which were analysed and played to sighted and blind listeners inexperienced in echolocation. The sounds were also manipulated to remove cues unrelated to spectral shape. Most listeners could accurately detect hard flat objects using changes in spectral shape. The useful spectral changes for object detection occurred above approximately 3 kHz, as with object localisation. However, energy in the sounds below 3 kHz was required to exploit changes in spectral shape for object detection, whereas energy below 3 kHz impaired object localisation. Further recordings showed that the spectral changes were diminished by room reverberation. While good high-frequency hearing is generally important for echolocation, the optimal echo-generating stimulus will probably depend on the task. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

  6. Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain

    International Nuclear Information System (INIS)

    Wang, K; Yu, T; Meng, Q Y; Wang, G K; Li, S P; Liu, S H

    2014-01-01

    Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably

  7. Enzyme catalytic resonance scattering spectral detection of trace ...

    African Journals Online (AJOL)

    27.6 μM, with a linear regression equation of ΔI530 nm = 17.1C + 1.6, a relative coefficient of 0.9996 and a detection limit of 0.03 μM H2O2. This proposed method was applied to detect hydrogen peroxide in rain water, with sensitivity, selectivity, ...

  8. Videodensitometric quantitative angiography after coronary balloon angioplasty, compared to edge-detection quantitative angiography and intracoronary ultrasound imaging

    NARCIS (Netherlands)

    Peters, R. J.; Kok, W. E.; Pasterkamp, G.; von Birgelen, C.; Prins, M. [=Martin H.; Serruys, P. W.

    2000-01-01

    AIMS: To assess the value of videodensitometric quantification of the coronary lumen after angioplasty by comparison to two other techniques of coronary artery lumen quantification. METHODS AND RESULTS: Videodensitometric quantitative angiography, edge detection quantitative angiography and 30 MHz

  9. Edge Detection from RGB-D Image Based on Structured Forests

    Directory of Open Access Journals (Sweden)

    Heng Zhang

    2016-01-01

    Full Text Available This paper looks into the fundamental problem in computer vision: edge detection. We propose a new edge detector using structured random forests as the classifier, which can make full use of RGB-D image information from Kinect. Before classification, the adaptive bilateral filter is used for the denoising processing of the depth image. As data sources, information of 13 channels from RGB-D image is computed. In order to train the random forest classifier, the approximation measurement of the information gain is used. All the structured labels at a given node are mapped to a discrete set of labels using the Principal Component Analysis (PCA method. NYUD2 dataset is used to train our structured random forests. The random forest algorithm is used to classify the RGB-D image information for extracting the edge of the image. In addition to the proposed methodology, the quantitative comparisons of different algorithms are presented. The results of the experiments demonstrate the significant improvements of our algorithm over the state of the art.

  10. Edge detection of magnetic anomalies using analytic signal of tilt angle (ASTA)

    Science.gov (United States)

    Alamdar, K.; Ansari, A. H.; Ghorbani, A.

    2009-04-01

    Magnetic is a commonly used geophysical technique to identify and image potential subsurface targets. Interpretation of magnetic anomalies is a complex process due to the superposition of multiple magnetic sources, presence of geologic and cultural noise and acquisition and positioning error. Both the vertical and horizontal derivatives of potential field data are useful; horizontal derivative, enhance edges whereas vertical derivative narrow the width of anomaly and so locate source bodies more accurately. We can combine vertical and horizontal derivative of magnetic field to achieve analytic signal which is independent to body magnetization direction and maximum value of this lies over edges of body directly. Tilt angle filter is phased-base filter and is defined as angle between vertical derivative and total horizontal derivative. Tilt angle value differ from +90 degree to -90 degree and its zero value lies over body edge. One of disadvantage of this filter is when encountering with deep sources the detected edge is blurred. For overcome this problem many authors introduced new filters such as total horizontal derivative of tilt angle or vertical derivative of tilt angle which Because of using high-order derivative in these filters results may be too noisy. If we combine analytic signal and tilt angle, a new filter termed (ASTA) is produced which its maximum value lies directly over body edge and is easer than tilt angle to delineate body edge and no complicity of tilt angle. In this work new filter has been demonstrated on magnetic data from an area in Sar- Cheshme region in Iran. This area is located in 55 degree longitude and 32 degree latitude and is a copper potential region. The main formation in this area is Andesith and Trachyandezite. Magnetic surveying was employed to separate the boundaries of Andezite and Trachyandezite from adjacent area. In this regard a variety of filters such as analytic signal, tilt angle and ASTA filter have been applied which

  11. Detecting edges in the X-ray surface brightness of galaxy clusters

    Science.gov (United States)

    Sanders, J. S.; Fabian, A. C.; Russell, H. R.; Walker, S. A.; Blundell, K. M.

    2016-08-01

    The effects of many physical processes in the intracluster medium of galaxy clusters imprint themselves in X-ray surface brightness images. It is therefore important to choose optimal methods for extracting information from and enhancing the interpretability of such images. We describe in detail a gradient filtering edge detection method that we previously applied to images of the Centaurus cluster of galaxies. The Gaussian gradient filter measures the gradient in the surface brightness distribution on particular spatial scales. We apply this filter on different scales to Chandra X-ray observatory images of two clusters with active galactic nucleus feedback, the Perseus cluster and M 87, and a merging system, A 3667. By combining filtered images on different scales using radial filters spectacular images of the edges in a cluster are produced. We describe how to assess the significance of features in filtered images. We find the gradient filtering technique to have significant advantages for detecting many kinds of features compared to other analysis techniques, such as unsharp masking. Filtering cluster images in this way in a hard energy band allows shocks to be detected.

  12. Edge Detection on Images of Pseudoimpedance Section Supported by Context and Adaptive Transformation Model Images

    Directory of Open Access Journals (Sweden)

    Kawalec-Latała Ewa

    2014-03-01

    Full Text Available Most of underground hydrocarbon storage are located in depleted natural gas reservoirs. Seismic survey is the most economical source of detailed subsurface information. The inversion of seismic section for obtaining pseudoacoustic impedance section gives the possibility to extract detailed subsurface information. The seismic wavelet parameters and noise briefly influence the resolution. Low signal parameters, especially long signal duration time and the presence of noise decrease pseudoimpedance resolution. Drawing out from measurement or modelled seismic data approximation of distribution of acoustic pseuoimpedance leads us to visualisation and images useful to stratum homogeneity identification goal. In this paper, the improvement of geologic section image resolution by use of minimum entropy deconvolution method before inversion is applied. The author proposes context and adaptive transformation of images and edge detection methods as a way to increase the effectiveness of correct interpretation of simulated images. In the paper, the edge detection algorithms using Sobel, Prewitt, Robert, Canny operators as well as Laplacian of Gaussian method are emphasised. Wiener filtering of image transformation improving rock section structure interpretation pseudoimpedance matrix on proper acoustic pseudoimpedance value, corresponding to selected geologic stratum. The goal of the study is to develop applications of image transformation tools to inhomogeneity detection in salt deposits.

  13. A 3D edge detection technique for surface extraction in computed tomography for dimensional metrology applications

    DEFF Research Database (Denmark)

    Yagüe-Fabra, J.A.; Ontiveros, S.; Jiménez, R.

    2013-01-01

    Many factors influence the measurement uncertainty when using computed tomography for dimensional metrology applications. One of the most critical steps is the surface extraction phase. An incorrect determination of the surface may significantly increase the measurement uncertainty. This paper...... presents an edge detection method for the surface extraction based on a 3D Canny algorithm with sub-voxel resolution. The advantages of this method are shown in comparison with the most commonly used technique nowadays, i.e. the local threshold definition. Both methods are applied to reference standards...

  14. A Single Sided Edge Marking Method for Detecting Pectoral Muscle in Digital Mammograms

    Directory of Open Access Journals (Sweden)

    G. Toz

    2018-02-01

    Full Text Available In the computer-assisted diagnosis of breast cancer, the removal of pectoral muscle from mammograms is very important. In this study, a new method, called Single-Sided Edge Marking (SSEM technique, is proposed for the identification of the pectoral muscle border from mammograms. 60 mammograms from the INbreast database were used to test the proposed method. The results obtained were compared for False Positive Rate, False Negative Rate, and Sensitivity using the ground truth values pre-determined by radiologists for the same images. Accordingly, it has been shown that the proposed method can detect the pectoral muscle border with an average of 95.6% sensitivity.

  15. Edge Detection and Feature Line Tracing in 3D-Point Clouds by Analyzing Geometric Properties of Neighborhoods

    Directory of Open Access Journals (Sweden)

    Huan Ni

    2016-09-01

    Full Text Available This paper presents an automated and effective method for detecting 3D edges and tracing feature lines from 3D-point clouds. This method is named Analysis of Geometric Properties of Neighborhoods (AGPN, and it includes two main steps: edge detection and feature line tracing. In the edge detection step, AGPN analyzes geometric properties of each query point’s neighborhood, and then combines RANdom SAmple Consensus (RANSAC and angular gap metric to detect edges. In the feature line tracing step, feature lines are traced by a hybrid method based on region growing and model fitting in the detected edges. Our approach is experimentally validated on complex man-made objects and large-scale urban scenes with millions of points. Comparative studies with state-of-the-art methods demonstrate that our method obtains a promising, reliable, and high performance in detecting edges and tracing feature lines in 3D-point clouds. Moreover, AGPN is insensitive to the point density of the input data.

  16. Spectral Correlation of Multicarrier Modulated Signals and Its Application for Signal Detection

    Directory of Open Access Journals (Sweden)

    Zhang Haijian

    2010-01-01

    Full Text Available Spectral correlation theory for cyclostationary time-series signals has been studied for decades. Explicit formulas of spectral correlation function for various types of analog-modulated and digital-modulated signals are already derived. In this paper, we investigate and exploit the cyclostationarity characteristics for two kinds of multicarrier modulated (MCM signals: conventional OFDM and filter bank based multicarrier (FBMC signals. The spectral correlation characterization of MCM signal can be described by a special linear periodic time-variant (LPTV system. Using this LPTV description, we have derived the explicit theoretical formulas of nonconjugate and conjugate cyclic autocorrelation function (CAF and spectral correlation function (SCF for OFDM and FBMC signals. According to theoretical spectral analysis, Cyclostationary Signatures (CS are artificially embedded into MCM signal and a low-complexity signature detector is, therefore, presented for detecting MCM signal. Theoretical analysis and simulation results demonstrate the efficiency and robustness of this CS detector compared to traditionary energy detector.

  17. Detection of time-varying harmonic amplitude alterations due to spectral interpolations between musical instrument tones.

    Science.gov (United States)

    Horner, Andrew B; Beauchamp, James W; So, Richard H Y

    2009-01-01

    Gradated spectral interpolations between musical instrument tone pairs were used to investigate discrimination as a function of time-averaged spectral difference. All possible nonidentical pairs taken from a collection of eight musical instrument sounds consisting of bassoon, clarinet, flute, horn, oboe, saxophone, trumpet, and violin were tested. For each pair, several tones were generated with different balances between the primary and secondary instruments, where the balance was fixed across the duration of each tone. Among primary instruments it was found that changes to horn and bassoon [corrected] were most easily discriminable, while changes to saxophone and trumpet timbres were least discriminable. Among secondary instruments, the clarinet had the strongest effect on discrimination, whereas the bassoon had the least effect. For primary instruments, strong negative correlations were found between discrimination and their spectral incoherences, suggesting that the presence of dynamic spectral variations tends to increase the difficulty of detecting time-varying alterations such as spectral interpolation.

  18. Detection of plum pox virus infection in selection plum trees using spectral imaging

    Science.gov (United States)

    Angelova, Liliya; Stoev, Antoniy; Borisova, Ekaterina; Avramov, Latchezar

    2016-01-01

    Plum pox virus (PPV) is among the most studied viral diseases in the world in plants. It is considered to be one of the most devastating diseases of stone fruits in terms of agronomic impact and economic importance. Noninvasive, fast and reliable techniques are required for evaluation of the pathology in selection trees with economic impact. Such advanced tools for PPV detection could be optical techniques as light-induced fluorescence and diffuse reflectance spectroscopies. Specific regions in the electromagnetic spectra have been found to provide information about the physiological stress in plants, and consequently, diseased plants usually exhibit different spectral signature than non-stressed healthy plants in those specific ranges. In this study spectral reflectance and chlorophyll fluorescence were used for the identification of biotic stress caused by the pox virus on plum trees. The spectral responses of healthy and infected leaves from cultivars, which are widespread in Bulgaria were investigated. The two applied techniques revealed statistically significant differences between the spectral data of healthy plum leaves and those infected by PPV in the visible and near-infrared spectral ranges. Their application for biotic stress detection helps in monitoring diseases in plants using the different plant spectral properties in these spectral ranges. The strong relationship between the results indicates the applicability of diffuse reflectance and fluorescence techniques for conducting health condition assessments of vegetation and their importance for plant protection practices.

  19. Comparison of edge detection techniques for M7 subtype Leukemic cell in terms of noise filters and threshold value

    Directory of Open Access Journals (Sweden)

    Abdul Salam Afifah Salmi

    2017-01-01

    Full Text Available This paper will focus on the study and identifying various threshold values for two commonly used edge detection techniques, which are Sobel and Canny Edge detection. The idea is to determine which values are apt in giving accurate results in identifying a particular leukemic cell. In addition, evaluating suitability of edge detectors are also essential as feature extraction of the cell depends greatly on image segmentation (edge detection. Firstly, an image of M7 subtype of Acute Myelocytic Leukemia (AML is chosen due to its diagnosing which were found lacking. Next, for an enhancement in image quality, noise filters are applied. Hence, by comparing images with no filter, median and average filter, useful information can be acquired. Each threshold value is fixed with value 0, 0.25 and 0.5. From the investigation found, without any filter, Canny with a threshold value of 0.5 yields the best result.

  20. Dysphonia Detected by Pattern Recognition of Spectral Composition.

    Science.gov (United States)

    Leinonen, Lea; And Others

    1992-01-01

    This study analyzed production of a long vowel sound within Finnish words by normal or dysphonic voices, using the Self-Organizing Map, the artificial neural network algorithm of T. Kohonen which produces two-dimensional representations of speech. The method was found to be both sensitive and specific in the detection of dysphonia. (Author/JDD)

  1. Performance evaluation of canny edge detection on a tiled multicore architecture

    Science.gov (United States)

    Brethorst, Andrew Z.; Desai, Nehal; Enright, Douglas P.; Scrofano, Ronald

    2011-01-01

    In the last few years, a variety of multicore architectures have been used to parallelize image processing applications. In this paper, we focus on assessing the parallel speed-ups of different Canny edge detection parallelization strategies on the Tile64, a tiled multicore architecture developed by the Tilera Corporation. Included in these strategies are different ways Canny edge detection can be parallelized, as well as differences in data management. The two parallelization strategies examined were loop-level parallelism and domain decomposition. Loop-level parallelism is achieved through the use of OpenMP,1 and it is capable of parallelization across the range of values over which a loop iterates. Domain decomposition is the process of breaking down an image into subimages, where each subimage is processed independently, in parallel. The results of the two strategies show that for the same number of threads, programmer implemented, domain decomposition exhibits higher speed-ups than the compiler managed, loop-level parallelism implemented with OpenMP.

  2. Dynamical System Approach for Edge Detection Using Coupled FitzHugh-Nagumo Neurons.

    Science.gov (United States)

    Li, Shaobai; Dasmahapatra, Srinandan; Maharatna, Koushik

    2015-12-01

    The prospect of emulating the impressive computational capabilities of biological systems has led to considerable interest in the design of analog circuits that are potentially implementable in very large scale integration CMOS technology and are guided by biologically motivated models. For example, simple image processing tasks, such as the detection of edges in binary and grayscale images, have been performed by networks of FitzHugh-Nagumo-type neurons using the reaction-diffusion models. However, in these studies, the one-to-one mapping of image pixels to component neurons makes the size of the network a critical factor in any such implementation. In this paper, we develop a simplified version of the employed reaction-diffusion model in three steps. In the first step, we perform a detailed study to locate this threshold using continuous Lyapunov exponents from dynamical system theory. Furthermore, we render the diffusion in the system to be anisotropic, with the degree of anisotropy being set by the gradients of grayscale values in each image. The final step involves a simplification of the model that is achieved by eliminating the terms that couple the membrane potentials of adjacent neurons. We apply our technique to detect edges in data sets of artificially generated and real images, and we demonstrate that the performance is as good if not better than that of the previous methods without increasing the size of the network.

  3. Real-time biscuit tile image segmentation method based on edge detection.

    Science.gov (United States)

    Matić, Tomislav; Aleksi, Ivan; Hocenski, Željko; Kraus, Dieter

    2018-05-01

    In this paper we propose a novel real-time Biscuit Tile Segmentation (BTS) method for images from ceramic tile production line. BTS method is based on signal change detection and contour tracing with a main goal of separating tile pixels from background in images captured on the production line. Usually, human operators are visually inspecting and classifying produced ceramic tiles. Computer vision and image processing techniques can automate visual inspection process if they fulfill real-time requirements. Important step in this process is a real-time tile pixels segmentation. BTS method is implemented for parallel execution on a GPU device to satisfy the real-time constraints of tile production line. BTS method outperforms 2D threshold-based methods, 1D edge detection methods and contour-based methods. Proposed BTS method is in use in the biscuit tile production line. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  4. Multiresolution edge detection using enhanced fuzzy c-means clustering for ultrasound image speckle reduction

    Energy Technology Data Exchange (ETDEWEB)

    Tsantis, Stavros [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 26504 (Greece); Spiliopoulos, Stavros; Karnabatidis, Dimitrios [Department of Radiology, School of Medicine, University of Patras, Rion, GR 26504 (Greece); Skouroliakou, Aikaterini [Department of Energy Technology Engineering, Technological Education Institute of Athens, Athens 12210 (Greece); Hazle, John D. [Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States); Kagadis, George C., E-mail: gkagad@gmail.com, E-mail: George.Kagadis@med.upatras.gr, E-mail: GKagadis@mdanderson.org [Department of Medical Physics, School of Medicine, University of Patras, Rion, GR 26504, Greece and Department of Imaging Physics, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030 (United States)

    2014-07-15

    Purpose: Speckle suppression in ultrasound (US) images of various anatomic structures via a novel speckle noise reduction algorithm. Methods: The proposed algorithm employs an enhanced fuzzy c-means (EFCM) clustering and multiresolution wavelet analysis to distinguish edges from speckle noise in US images. The edge detection procedure involves a coarse-to-fine strategy with spatial and interscale constraints so as to classify wavelet local maxima distribution at different frequency bands. As an outcome, an edge map across scales is derived whereas the wavelet coefficients that correspond to speckle are suppressed in the inverse wavelet transform acquiring the denoised US image. Results: A total of 34 thyroid, liver, and breast US examinations were performed on a Logiq 9 US system. Each of these images was subjected to the proposed EFCM algorithm and, for comparison, to commercial speckle reduction imaging (SRI) software and another well-known denoising approach, Pizurica's method. The quantification of the speckle suppression performance in the selected set of US images was carried out via Speckle Suppression Index (SSI) with results of 0.61, 0.71, and 0.73 for EFCM, SRI, and Pizurica's methods, respectively. Peak signal-to-noise ratios of 35.12, 33.95, and 29.78 and edge preservation indices of 0.94, 0.93, and 0.86 were found for the EFCM, SIR, and Pizurica's method, respectively, demonstrating that the proposed method achieves superior speckle reduction performance and edge preservation properties. Based on two independent radiologists’ qualitative evaluation the proposed method significantly improved image characteristics over standard baseline B mode images, and those processed with the Pizurica's method. Furthermore, it yielded results similar to those for SRI for breast and thyroid images significantly better results than SRI for liver imaging, thus improving diagnostic accuracy in both superficial and in-depth structures. Conclusions: A

  5. Multiresolution edge detection using enhanced fuzzy c-means clustering for ultrasound image speckle reduction

    International Nuclear Information System (INIS)

    Tsantis, Stavros; Spiliopoulos, Stavros; Karnabatidis, Dimitrios; Skouroliakou, Aikaterini; Hazle, John D.; Kagadis, George C.

    2014-01-01

    Purpose: Speckle suppression in ultrasound (US) images of various anatomic structures via a novel speckle noise reduction algorithm. Methods: The proposed algorithm employs an enhanced fuzzy c-means (EFCM) clustering and multiresolution wavelet analysis to distinguish edges from speckle noise in US images. The edge detection procedure involves a coarse-to-fine strategy with spatial and interscale constraints so as to classify wavelet local maxima distribution at different frequency bands. As an outcome, an edge map across scales is derived whereas the wavelet coefficients that correspond to speckle are suppressed in the inverse wavelet transform acquiring the denoised US image. Results: A total of 34 thyroid, liver, and breast US examinations were performed on a Logiq 9 US system. Each of these images was subjected to the proposed EFCM algorithm and, for comparison, to commercial speckle reduction imaging (SRI) software and another well-known denoising approach, Pizurica's method. The quantification of the speckle suppression performance in the selected set of US images was carried out via Speckle Suppression Index (SSI) with results of 0.61, 0.71, and 0.73 for EFCM, SRI, and Pizurica's methods, respectively. Peak signal-to-noise ratios of 35.12, 33.95, and 29.78 and edge preservation indices of 0.94, 0.93, and 0.86 were found for the EFCM, SIR, and Pizurica's method, respectively, demonstrating that the proposed method achieves superior speckle reduction performance and edge preservation properties. Based on two independent radiologists’ qualitative evaluation the proposed method significantly improved image characteristics over standard baseline B mode images, and those processed with the Pizurica's method. Furthermore, it yielded results similar to those for SRI for breast and thyroid images significantly better results than SRI for liver imaging, thus improving diagnostic accuracy in both superficial and in-depth structures. Conclusions: A

  6. Application of Reflectance Transformation Imaging Technique to Improve Automated Edge Detection in a Fossilized Oyster Reef

    Science.gov (United States)

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

    2016-04-01

    The world's largest fossilized oyster reef is located in Stetten, Lower Austria excavated during field campaigns of the Natural History Museum Vienna between 2005 and 2008. It is studied in paleontology to learn about change in climate from past events. In order to support this study, a laser scanning and photogrammetric campaign was organized in 2014 for 3D documentation of the large and complex site. The 3D point clouds and high resolution images from this field campaign are visualized by photogrammetric methods in form of digital surface models (DSM, 1 mm resolution) and orthophoto (0.5 mm resolution) to help paleontological interpretation of data. Due to size of the reef, automated analysis techniques are needed to interpret all digital data obtained from the field. One of the key components in successful automation is detection of oyster shell edges. We have tested Reflectance Transformation Imaging (RTI) to visualize the reef data sets for end-users through a cultural heritage viewing interface (RTIViewer). The implementation includes a Lambert shading method to visualize DSMs derived from terrestrial laser scanning using scientific software OPALS. In contrast to shaded RTI no devices consisting of a hardware system with LED lights, or a body to rotate the light source around the object are needed. The gray value for a given shaded pixel is related to the angle between light source and the normal at that position. Brighter values correspond to the slope surfaces facing the light source. Increasing of zenith angle results in internal shading all over the reef surface. In total, oyster reef surface contains 81 DSMs with 3 m x 2 m each. Their surface was illuminated by moving the virtual sun every 30 degrees (12 azimuth angles from 20-350) and every 20 degrees (4 zenith angles from 20-80). This technique provides paleontologists an interactive approach to virtually inspect the oyster reef, and to interpret the shell surface by changing the light source direction

  7. Non destructive defect detection by spectral density analysis.

    Science.gov (United States)

    Krejcar, Ondrej; Frischer, Robert

    2011-01-01

    The potential nondestructive diagnostics of solid objects is discussed in this article. The whole process is accomplished by consecutive steps involving software analysis of the vibration power spectrum (eventually acoustic emissions) created during the normal operation of the diagnosed device or under unexpected situations. Another option is to create an artificial pulse, which can help us to determine the actual state of the diagnosed device. The main idea of this method is based on the analysis of the current power spectrum density of the received signal and its postprocessing in the Matlab environment with a following sample comparison in the Statistica software environment. The last step, which is comparison of samples, is the most important, because it is possible to determine the status of the examined object at a given time. Nowadays samples are compared only visually, but this method can't produce good results. Further the presented filter can choose relevant data from a huge group of data, which originate from applying FFT (Fast Fourier Transform). On the other hand, using this approach they can be subjected to analysis with the assistance of a neural network. If correct and high-quality starting data are provided to the initial network, we are able to analyze other samples and state in which condition a certain object is. The success rate of this approximation, based on our testing of the solution, is now 85.7%. With further improvement of the filter, it could be even greater. Finally it is possible to detect defective conditions or upcoming limiting states of examined objects/materials by using only one device which contains HW and SW parts. This kind of detection can provide significant financial savings in certain cases (such as continuous casting of iron where it could save hundreds of thousands of USD).

  8. Real-time detection of natural objects using AM-coded spectral matching imager

    Science.gov (United States)

    Kimachi, Akira

    2005-01-01

    This paper describes application of the amplitude-modulation (AM)-coded spectral matching imager (SMI) to real-time detection of natural objects such as human beings, animals, vegetables, or geological objects or phenomena, which are much more liable to change with time than artificial products while often exhibiting characteristic spectral functions associated with some specific activity states. The AM-SMI produces correlation between spectral functions of the object and a reference at each pixel of the correlation image sensor (CIS) in every frame, based on orthogonal amplitude modulation (AM) of each spectral channel and simultaneous demodulation of all channels on the CIS. This principle makes the SMI suitable to monitoring dynamic behavior of natural objects in real-time by looking at a particular spectral reflectance or transmittance function. A twelve-channel multispectral light source was developed with improved spatial uniformity of spectral irradiance compared to a previous one. Experimental results of spectral matching imaging of human skin and vegetable leaves are demonstrated, as well as a preliminary feasibility test of imaging a reflective object using a test color chart.

  9. Classification with an edge: Improving semantic image segmentation with boundary detection

    Science.gov (United States)

    Marmanis, D.; Schindler, K.; Wegner, J. D.; Galliani, S.; Datcu, M.; Stilla, U.

    2018-01-01

    We present an end-to-end trainable deep convolutional neural network (DCNN) for semantic segmentation with built-in awareness of semantically meaningful boundaries. Semantic segmentation is a fundamental remote sensing task, and most state-of-the-art methods rely on DCNNs as their workhorse. A major reason for their success is that deep networks learn to accumulate contextual information over very large receptive fields. However, this success comes at a cost, since the associated loss of effective spatial resolution washes out high-frequency details and leads to blurry object boundaries. Here, we propose to counter this effect by combining semantic segmentation with semantically informed edge detection, thus making class boundaries explicit in the model. First, we construct a comparatively simple, memory-efficient model by adding boundary detection to the SEGNET encoder-decoder architecture. Second, we also include boundary detection in FCN-type models and set up a high-end classifier ensemble. We show that boundary detection significantly improves semantic segmentation with CNNs in an end-to-end training scheme. Our best model achieves >90% overall accuracy on the ISPRS Vaihingen benchmark.

  10. Fast and accurate spectral estimation for online detection of partial broken bar in induction motors

    Science.gov (United States)

    Samanta, Anik Kumar; Naha, Arunava; Routray, Aurobinda; Deb, Alok Kanti

    2018-01-01

    In this paper, an online and real-time system is presented for detecting partial broken rotor bar (BRB) of inverter-fed squirrel cage induction motors under light load condition. This system with minor modifications can detect any fault that affects the stator current. A fast and accurate spectral estimator based on the theory of Rayleigh quotient is proposed for detecting the spectral signature of BRB. The proposed spectral estimator can precisely determine the relative amplitude of fault sidebands and has low complexity compared to available high-resolution subspace-based spectral estimators. Detection of low-amplitude fault components has been improved by removing the high-amplitude fundamental frequency using an extended-Kalman based signal conditioner. Slip is estimated from the stator current spectrum for accurate localization of the fault component. Complexity and cost of sensors are minimal as only a single-phase stator current is required. The hardware implementation has been carried out on an Intel i7 based embedded target ported through the Simulink Real-Time. Evaluation of threshold and detectability of faults with different conditions of load and fault severity are carried out with empirical cumulative distribution function.

  11. A Cost Effective Multi-Spectral Scanner for Natural Gas Detection

    Energy Technology Data Exchange (ETDEWEB)

    Yudaya Sivathanu; Jongmook Lim; Vinoo Narayanan; Seonghyeon Park

    2005-12-07

    The objective of this project is to design, fabricate and demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first year of the project, a laboratory version of the multi-spectral scanner was designed, fabricated, and tested at EnUrga Inc. The multi-spectral scanner was also evaluated using a blind Department of Energy study at the Rocky Mountain Oilfield Testing Center. The performance of the scanner was inconsistent during the blind study. However, most of the leaks were outside the view of the multi-spectral scanner that was developed during the first year of the project. Therefore, a definite evaluation of the capability of the scanner was not obtained. Despite the results, sufficient number of plumes was detected fully confirming the feasibility of the multi-spectral scanner. During the second year, the optical design of the scanner was changed to improve the sensitivity of the system. Laboratory tests show that the system can reliably detect small leaks (20 SCFH) at 30 to 50 feet. A prototype scanner was built and evaluated during the second year of the project. Only laboratory evaluations were completed during the second year. The laboratory evaluations show the feasibility of using the scanner to determine natural gas pipeline leaks. Further field evaluations and optimization of the scanner are required before commercialization of the scanner can be initiated.

  12. Detecting an infrared photon within an hour. Transition-edge detector at ALPS-II

    Energy Technology Data Exchange (ETDEWEB)

    Dreyling-Eschweiler, Jan [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Hamburg Univ. (Germany). Inst. fuer Experimentalphysik; Horns, Dieter [Hamburg Univ. (Germany). Inst. fuer Experimentalphysik; Collaboration: ALPS-II collaboration

    2013-09-15

    An essential design requirement of the ALPS-II experiment is the efficient detection of single photons with a very low instrumental background of 10 {mu}Hz. In 2011 the ALPS collaboration started to set up a TES detector (Transition-Edge Sensor) for ALPS-II, the second phase of the experiment. Since mid of 2013 the setup is ready for characterization in the ALPS laboratory: an ADR cryostat (Adiabatic Demagnetization Refrigerator) as millikelvin environment, a low noise SQUID (Superconducting Quantum Interference Device) with electronics for read-out and a fiber-coupled high-efficient TES for near-infrared photons as sensor. First measurements have shown a good discrimination between noise and 1064 nm signals.

  13. Implementation in an FPGA circuit of Edge detection algorithm based on the Discrete Wavelet Transforms

    Science.gov (United States)

    Bouganssa, Issam; Sbihi, Mohamed; Zaim, Mounia

    2017-07-01

    The 2D Discrete Wavelet Transform (DWT) is a computationally intensive task that is usually implemented on specific architectures in many imaging systems in real time. In this paper, a high throughput edge or contour detection algorithm is proposed based on the discrete wavelet transform. A technique for applying the filters on the three directions (Horizontal, Vertical and Diagonal) of the image is used to present the maximum of the existing contours. The proposed architectures were designed in VHDL and mapped to a Xilinx Sparten6 FPGA. The results of the synthesis show that the proposed architecture has a low area cost and can operate up to 100 MHz, which can perform 2D wavelet analysis for a sequence of images while maintaining the flexibility of the system to support an adaptive algorithm.

  14. Detecting an infrared photon within an hour. Transition-edge detector at ALPS-II

    International Nuclear Information System (INIS)

    Dreyling-Eschweiler, Jan; Hamburg Univ.; Horns, Dieter

    2013-09-01

    An essential design requirement of the ALPS-II experiment is the efficient detection of single photons with a very low instrumental background of 10 μHz. In 2011 the ALPS collaboration started to set up a TES detector (Transition-Edge Sensor) for ALPS-II, the second phase of the experiment. Since mid of 2013 the setup is ready for characterization in the ALPS laboratory: an ADR cryostat (Adiabatic Demagnetization Refrigerator) as millikelvin environment, a low noise SQUID (Superconducting Quantum Interference Device) with electronics for read-out and a fiber-coupled high-efficient TES for near-infrared photons as sensor. First measurements have shown a good discrimination between noise and 1064 nm signals.

  15. A thesis on the Development of an Automated SWIFT Edge Detection Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Trujillo, Christopher J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-07-28

    Throughout the world, scientists and engineers such as those at Los Alamos National Laboratory, perform research and testing unique only to applications aimed towards advancing technology, and understanding the nature of materials. With this testing, comes a need for advanced methods of data acquisition and most importantly, a means of analyzing and extracting the necessary information from such acquired data. In this thesis, I aim to produce an automated method implementing advanced image processing techniques and tools to analyze SWIFT image datasets for Detonator Technology at Los Alamos National Laboratory. Such an effective method for edge detection and point extraction can prove to be advantageous in analyzing such unique datasets and provide for consistency in producing results.

  16. A New Parallel Approach for Accelerating the GPU-Based Execution of Edge Detection Algorithms.

    Science.gov (United States)

    Emrani, Zahra; Bateni, Soroosh; Rabbani, Hossein

    2017-01-01

    Real-time image processing is used in a wide variety of applications like those in medical care and industrial processes. This technique in medical care has the ability to display important patient information graphi graphically, which can supplement and help the treatment process. Medical decisions made based on real-time images are more accurate and reliable. According to the recent researches, graphic processing unit (GPU) programming is a useful method for improving the speed and quality of medical image processing and is one of the ways of real-time image processing. Edge detection is an early stage in most of the image processing methods for the extraction of features and object segments from a raw image. The Canny method, Sobel and Prewitt filters, and the Roberts' Cross technique are some examples of edge detection algorithms that are widely used in image processing and machine vision. In this work, these algorithms are implemented using the Compute Unified Device Architecture (CUDA), Open Source Computer Vision (OpenCV), and Matrix Laboratory (MATLAB) platforms. An existing parallel method for Canny approach has been modified further to run in a fully parallel manner. This has been achieved by replacing the breadth- first search procedure with a parallel method. These algorithms have been compared by testing them on a database of optical coherence tomography images. The comparison of results shows that the proposed implementation of the Canny method on GPU using the CUDA platform improves the speed of execution by 2-100× compared to the central processing unit-based implementation using the OpenCV and MATLAB platforms.

  17. Segmentation of 3D ultrasound computer tomography reflection images using edge detection and surface fitting

    Science.gov (United States)

    Hopp, T.; Zapf, M.; Ruiter, N. V.

    2014-03-01

    An essential processing step for comparison of Ultrasound Computer Tomography images to other modalities, as well as for the use in further image processing, is to segment the breast from the background. In this work we present a (semi-) automated 3D segmentation method which is based on the detection of the breast boundary in coronal slice images and a subsequent surface fitting. The method was evaluated using a software phantom and in-vivo data. The fully automatically processed phantom results showed that a segmentation of approx. 10% of the slices of a dataset is sufficient to recover the overall breast shape. Application to 16 in-vivo datasets was performed successfully using semi-automated processing, i.e. using a graphical user interface for manual corrections of the automated breast boundary detection. The processing time for the segmentation of an in-vivo dataset could be significantly reduced by a factor of four compared to a fully manual segmentation. Comparison to manually segmented images identified a smoother surface for the semi-automated segmentation with an average of 11% of differing voxels and an average surface deviation of 2mm. Limitations of the edge detection may be overcome by future updates of the KIT USCT system, allowing a fully-automated usage of our segmentation approach.

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

    Science.gov (United States)

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

    2011-04-01

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

  19. Noise and specific detectivity measurements on high-temperature superconducting transition-edge bolometers

    International Nuclear Information System (INIS)

    Black, R.D.; Mogro-campero, A.; Turner, L.G.

    1990-01-01

    The effects of thermal fluctuation noise in thermal detectors can be lessened by reducing heat capacity and thermal conductance. An attempt to accomplish this with the YBa2Cu3O(7-x) (YBCO) bolometer by making YBCO resistors on thermally isolated membranes is reported. The spectral power of the electrical noise of YBCO films on SrTiO3, bulk silicon with a buffer layer, and in thin dielectric membranes is measured. It is found that 1/f noise predominates in polycrystalline YBCO films on silicon-based substrates. Films on SrTiO3 with good electrical properties are dominated by thermal fluctuation noise, just as in the case of low-temperature superconductors. The implications of these findings for bolometer are addressed. The specific detectivity of a bolometric pixel made on bulk SrTiO3 is reported. 14 refs

  20. Comparative study of Poincaré plot analysis using short electroencephalogram signals during anaesthesia with spectral edge frequency 95 and bispectral index.

    Science.gov (United States)

    Hayashi, K; Yamada, T; Sawa, T

    2015-03-01

    The return or Poincaré plot is a non-linear analytical approach in a two-dimensional plane, where a timed signal is plotted against itself after a time delay. Its scatter pattern reflects the randomness and variability in the signals. Quantification of a Poincaré plot of the electroencephalogram has potential to determine anaesthesia depth. We quantified the degree of dispersion (i.e. standard deviation, SD) along the diagonal line of the electroencephalogram-Poincaré plot (named as SD1/SD2), and compared SD1/SD2 values with spectral edge frequency 95 (SEF95) and bispectral index values. The regression analysis showed a tight linear regression equation with a coefficient of determination (R(2) ) value of 0.904 (p plot tightly correlates with SEF95, reflecting anaesthesia-dependent changes in electroencephalogram oscillation. © 2014 The Association of Anaesthetists of Great Britain and Ireland.

  1. MO-FG-CAMPUS-IeP1-01: Alternative K-Edge Filters for Low-Energy Image Acquisition in Contrast Enhanced Spectral Mammography

    Energy Technology Data Exchange (ETDEWEB)

    Shrestha, S; Vedantham, S; Karellas, A [University of Massachusetts Medical School, Worcester, MA (United States)

    2016-06-15

    Purpose: In Contrast Enhanced Spectral Mammography (CESM), Rh filter is often used during low-energy image acquisition. The potential for using Ag, In and Sn filters, which exhibit K-edge closer to, and just below that of Iodine, instead of the Rh filter, was investigated for the low-energy image acquisition. Methods: Analytical computations of the half-value thickness (HVT) and the photon fluence per mAs (photons/mm2/mAs) for 50µm Rh were compared with other potential K-edge filters (Ag, In and Sn), all with K-absorption edge below that of Iodine. Two strategies were investigated: fixed kVp and filter thickness (50µm for all filters) resulting in HVT variation, and fixed kVp and HVT resulting in variation in Ag, In and Sn thickness. Monte Carlo simulations (GEANT4) were conducted to determine if the scatter-to-primary ratio (SPR) and the point spread function of scatter (scatter PSF) differed between Rh and other K-edge filters. Results: Ag, In and Sn filters (50µm thick) increased photon fluence/mAs by 1.3–1.4, 1.8–2, and 1.7–2 at 28-32 kVp compared to 50µm Rh, which could decrease exposure time. Additionally, the fraction of spectra closer to and just below Iodine’s K-edge increased with these filters, which could improve post-subtraction image contrast. For HVT matched to 50µm Rh filtered spectra, the thickness range for Ag, In, and Sn were (41,44)µm, (49,55)µm and (45,53)µm, and increased photon fluence/mAs by 1.5–1.7, 1.6–2, and 1.6–2.2, respectively. Monte Carlo simulations showed that neither the SPR nor the scatter PSF of Ag, In and Sn differed from Rh, indicating no additional detriment due to x-ray scatter. Conclusion: The use of Ag, In and Sn filters for low-energy image acquisition in CESM is potentially feasible and could decrease exposure time and may improve post-subtraction image contrast. Effect of these filters on radiation dose, contrast, noise and associated metrics are being investigated. Funding Support: Supported in

  2. [Fast Detection of Camellia Sinensis Growth Process and Tea Quality Informations with Spectral Technology: A Review].

    Science.gov (United States)

    Peng, Ji-yu; Song, Xing-lin; Liu, Fei; Bao, Yi-dan; He, Yong

    2016-03-01

    The research achievements and trends of spectral technology in fast detection of Camellia sinensis growth process information and tea quality information were being reviewed. Spectral technology is a kind of fast, nondestructive, efficient detection technology, which mainly contains infrared spectroscopy, fluorescence spectroscopy, Raman spectroscopy and mass spectroscopy. The rapid detection of Camellia sinensis growth process information and tea quality is helpful to realize the informatization and automation of tea production and ensure the tea quality and safety. This paper provides a review on its applications containing the detection of tea (Camellia sinensis) growing status(nitrogen, chlorophyll, diseases and insect pest), the discrimination of tea varieties, the grade discrimination of tea, the detection of tea internal quality (catechins, total polyphenols, caffeine, amino acid, pesticide residual and so on), the quality evaluation of tea beverage and tea by-product, the machinery of tea quality determination and discrimination. This paper briefly introduces the trends of the technology of the determination of tea growth process information, sensor and industrial application. In conclusion, spectral technology showed high potential to detect Camellia sinensis growth process information, to predict tea internal quality and to classify tea varieties and grades. Suitable chemometrics and preprocessing methods is helpful to improve the performance of the model and get rid of redundancy, which provides the possibility to develop the portable machinery. Future work is to develop the portable machinery and on-line detection system is recommended to improve the further application. The application and research achievement of spectral technology concerning about tea were outlined in this paper for the first time, which contained Camellia sinensis growth, tea production, the quality and safety of tea and by-produce and so on, as well as some problems to be solved

  3. Technology for detecting spectral radiance by a snapshot multi-imaging spectroradiometer

    Science.gov (United States)

    Zuber, Ralf; Stührmann, Ansgar; Gugg-Helminger, Anton; Seckmeyer, Gunther

    2017-12-01

    Technologies to determine spectral sky radiance distributions have evolved in recent years and have enabled new applications in remote sensing, for sky radiance measurements, in biological/diagnostic applications and luminance measurements. Most classical spectral imaging radiance technologies are based on mechanical and/or spectral scans. However, these methods require scanning time in which the spectral radiance distribution might change. To overcome this limitation, different so-called snapshot spectral imaging technologies have been developed that enable spectral and spatial non-scanning measurements. We present a new setup based on a facet mirror that is already used in imaging slicing spectrometers. By duplicating the input image instead of slicing it and using a specially designed entrance slit, we are able to select nearly 200 (14 × 14) channels within the field of view (FOV) for detecting spectral radiance in different directions. In addition, a megapixel image of the FOV is captured by an additional RGB camera. This image can be mapped onto the snapshot spectral image. In this paper, the mechanical setup, technical design considerations and first measurement results of a prototype are presented. For a proof of concept, the device is radiometrically calibrated and a 10 mm × 10 mm test pattern measured within a spectral range of 380 nm-800 nm with an optical bandwidth of 10 nm (full width at half maximum or FWHM). To show its potential in the UV spectral region, zenith sky radiance measurements in the UV of a clear sky were performed. Hence, the prototype was equipped with an entrance optic with a FOV of 0.5° and modified to obtain a radiometrically calibrated spectral range of 280 nm-470 nm with a FWHM of 3 nm. The measurement results have been compared to modeled data processed by UVSPEC, which showed deviations of less than 30%. This is far from being ideal, but an acceptable result with respect to available state

  4. VIBRATIONS DETECTION IN INDUSTRIAL PUMPS BASED ON SPECTRAL ANALYSIS TO INCREASE THEIR EFFICIENCY

    Directory of Open Access Journals (Sweden)

    Belhadef RACHID

    2016-01-01

    Full Text Available Spectral analysis is the key tool for the study of vibration signals in rotating machinery. In this work, the vibration analy-sis applied for conditional preventive maintenance of such machines is proposed, as part of resolved problems related to vibration detection on the organs of these machines. The vibration signal of a centrifugal pump was treated to mount the benefits of the approach proposed. The obtained results present the signal estimation of a pump vibration using Fourier transform technique compared by the spectral analysis methods based on Prony approach.

  5. Improved spectral kurtosis with adaptive redundant multiwavelet packet and its applications for rotating machinery fault detection

    International Nuclear Information System (INIS)

    Chen, Jinglong; Zi, Yanyang; He, Zhengjia; Yuan, Jing

    2012-01-01

    Rotating machinery fault detection is significant to avoid serious accidents and huge economic losses effectively. However, due to the vibration signal with the character of non-stationarity and nonlinearity, the detection and extraction of the fault feature turn into a challenging task. Therefore, a novel method called improved spectral kurtosis (ISK) with adaptive redundant multiwavelet packet (ARMP) is proposed for this task. Spectral kurtosis (SK) has been proved to be a powerful tool to detect and characterize the non-stationary signal. To improve the SK in filter limitation and enhance the resolution of spectral analysis as well as match fault feature optimally, the ARMP is introduced into the SK. Moreover, since kurtosis does not reflect the actual trend of periodic impulses, the SK is improved by incorporating an evaluation index called envelope spectrum entropy as supplement. The proposed method is applied to the rolling element bearing and gear fault detection to validate its reliability and effectiveness. Compared with the conventional frequency spectrum, envelope spectrum, original SK and some single wavelet methods, the results indicate that it could improve the accuracy of frequency-band selection and enhance the ability of rotating machinery fault detection. (paper)

  6. Fast retinal vessel detection and measurement using wavelets and edge location refinement.

    Directory of Open Access Journals (Sweden)

    Peter Bankhead

    Full Text Available The relationship between changes in retinal vessel morphology and the onset and progression of diseases such as diabetes, hypertension and retinopathy of prematurity (ROP has been the subject of several large scale clinical studies. However, the difficulty of quantifying changes in retinal vessels in a sufficiently fast, accurate and repeatable manner has restricted the application of the insights gleaned from these studies to clinical practice. This paper presents a novel algorithm for the efficient detection and measurement of retinal vessels, which is general enough that it can be applied to both low and high resolution fundus photographs and fluorescein angiograms upon the adjustment of only a few intuitive parameters. Firstly, we describe the simple vessel segmentation strategy, formulated in the language of wavelets, that is used for fast vessel detection. When validated using a publicly available database of retinal images, this segmentation achieves a true positive rate of 70.27%, false positive rate of 2.83%, and accuracy score of 0.9371. Vessel edges are then more precisely localised using image profiles computed perpendicularly across a spline fit of each detected vessel centreline, so that both local and global changes in vessel diameter can be readily quantified. Using a second image database, we show that the diameters output by our algorithm display good agreement with the manual measurements made by three independent observers. We conclude that the improved speed and generality offered by our algorithm are achieved without sacrificing accuracy. The algorithm is implemented in MATLAB along with a graphical user interface, and we have made the source code freely available.

  7. Exploiting physical constraints for multi-spectral exo-planet detection

    Science.gov (United States)

    Thiébaut, Éric; Devaney, Nicholas; Langlois, Maud; Hanley, Kenneth

    2016-07-01

    We derive a physical model of the on-axis PSF for a high contrast imaging system such as GPI or SPHERE. This model is based on a multi-spectral Taylor series expansion of the diffraction pattern and predicts that the speckles should be a combination of spatial modes with deterministic chromatic magnification and weighting. We propose to remove most of the residuals by fitting this model on a set of images at multiple wavelengths and times. On simulated data, we demonstrate that our approach achieves very good speckle suppression without additional heuristic parameters. The residual speckles1, 2 set the most serious limitation in the detection of exo-planets in high contrast coronographic images provided by instruments such as SPHERE3 at the VLT, GPI4, 5 at Gemini, or SCExAO6 at Subaru. A number of post-processing methods have been proposed to remove as much as possible of the residual speckles while preserving the signal from the planets. These methods exploit the fact that the speckles and the planetary signal have different temporal and spectral behaviors. Some methods like LOCI7 are based on angular differential imaging8 (ADI), spectral differential imaging9, 10 (SDI), or on a combination of ADI and SDI.11 Instead of working on image differences, we propose to tackle the exo-planet detection as an inverse problem where a model of the residual speckles is fit on the set of multi-spectral images and, possibly, multiple exposures. In order to reduce the number of degrees of freedom, we impose specific constraints on the spatio-spectral distribution of stellar speckles. These constraints are deduced from a multi-spectral Taylor series expansion of the diffraction pattern for an on-axis source which implies that the speckles are a combination of spatial modes with deterministic chromatic magnification and weighting. Using simulated data, the efficiency of speckle removal by fitting the proposed multi-spectral model is compared to the result of using an approximation

  8. Digital mammography: Mixed feature neural network with spectral entropy decision for detection of microcalcifications

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, B. [Univ. of South Florida, Tampa, FL (United States)]|[Nanjing Univ. of Posts and Telecommunications (China). Dept. of Telecommunication Engineering; Qian, W.; Clarke, L.P. [Univ. of South Florida, Tampa, FL (United States)

    1996-10-01

    A computationally efficient mixed feature based neural network (MFNN) is proposed for the detection of microcalcification clusters (MCC`s) in digitized mammograms. The MFNN employs features computed in both the spatial and spectral domain and uses spectral entropy as a decision parameter. Backpropagation with Kalman Filtering (KF) is employed to allow more efficient network training as required for evaluation of different features, input images, and related error analysis. A previously reported, wavelet-based image-enhancement method is also employed to enhance microcalcification clusters for improved detection. The relative performance of the MFNN for both the raw and enhanced images is evaluated using a common image database of 30 digitized mammograms, with 20 images containing 21 biopsy proven MCC`s and ten normal cases. The computed sensitivity (true positive (TP) detection rate) was 90.1% with an average low false positive (FP) detection of 0.71 MCCs/image for the enhanced images using a modified k-fold validation error estimation technique. The corresponding computed sensitivity for the raw images was reduced to 81.4% and with 0.59 FP`s MCCs/image. A relative comparison to an earlier neural network (NN) design, using only spatially related features, suggests the importance of the addition of spectral domain features when the raw image data are analyzed.

  9. Digital mammography: Mixed feature neural network with spectral entropy decision for detection of microcalcifications

    International Nuclear Information System (INIS)

    Zheng, B.

    1996-01-01

    A computationally efficient mixed feature based neural network (MFNN) is proposed for the detection of microcalcification clusters (MCC's) in digitized mammograms. The MFNN employs features computed in both the spatial and spectral domain and uses spectral entropy as a decision parameter. Backpropagation with Kalman Filtering (KF) is employed to allow more efficient network training as required for evaluation of different features, input images, and related error analysis. A previously reported, wavelet-based image-enhancement method is also employed to enhance microcalcification clusters for improved detection. The relative performance of the MFNN for both the raw and enhanced images is evaluated using a common image database of 30 digitized mammograms, with 20 images containing 21 biopsy proven MCC's and ten normal cases. The computed sensitivity (true positive (TP) detection rate) was 90.1% with an average low false positive (FP) detection of 0.71 MCCs/image for the enhanced images using a modified k-fold validation error estimation technique. The corresponding computed sensitivity for the raw images was reduced to 81.4% and with 0.59 FP's MCCs/image. A relative comparison to an earlier neural network (NN) design, using only spatially related features, suggests the importance of the addition of spectral domain features when the raw image data are analyzed

  10. Spectral feature characterization methods for blood stain detection in crime scene backgrounds

    Science.gov (United States)

    Yang, Jie; Mathew, Jobin J.; Dube, Roger R.; Messinger, David W.

    2016-05-01

    Blood stains are one of the most important types of evidence for forensic investigation. They contain valuable DNA information, and the pattern of the stains can suggest specifics about the nature of the violence that transpired at the scene. Blood spectral signatures containing unique reflectance or absorption features are important both for forensic on-site investigation and laboratory testing. They can be used for target detection and identification applied to crime scene hyperspectral imagery, and also be utilized to analyze the spectral variation of blood on various backgrounds. Non-blood stains often mislead the detection and can generate false alarms at a real crime scene, especially for dark and red backgrounds. This paper measured the reflectance of liquid blood and 9 kinds of non-blood samples in the range of 350 nm - 2500 nm in various crime scene backgrounds, such as pure samples contained in petri dish with various thicknesses, mixed samples with different colors and materials of fabrics, and mixed samples with wood, all of which are examined to provide sub-visual evidence for detecting and recognizing blood from non-blood samples in a realistic crime scene. The spectral difference between blood and non-blood samples are examined and spectral features such as "peaks" and "depths" of reflectance are selected. Two blood stain detection methods are proposed in this paper. The first method uses index to denote the ratio of "depth" minus "peak" over"depth" add"peak" within a wavelength range of the reflectance spectrum. The second method uses relative band depth of the selected wavelength ranges of the reflectance spectrum. Results show that the index method is able to discriminate blood from non-blood samples in most tested crime scene backgrounds, but is not able to detect it from black felt. Whereas the relative band depth method is able to discriminate blood from non-blood samples on all of the tested background material types and colors.

  11. Natural history of optical coherence tomography-detected non-flow-limiting edge dissections following drug-eluting stent implantation

    DEFF Research Database (Denmark)

    Radu, Maria D; Räber, Lorenz; Heo, Jungho

    2014-01-01

    history and clinical implications remain unclear. The objectives of the present study were to assess the morphology, healing response, and clinical outcomes of OCT-detected edge dissections using serial OCT imaging at baseline and at one year following drug-eluting stent (DES) implantation. METHODS...

  12. Systems and methods for selective detection and imaging in coherent Raman microscopy by spectral excitation shaping

    Science.gov (United States)

    Xie, Xiaoliang Sunney; Freudiger, Christian; Min, Wei

    2016-03-15

    A microscopy imaging system is disclosed that includes a light source system, a spectral shaper, a modulator system, an optics system, an optical detector and a processor. The light source system is for providing a first train of pulses and a second train of pulses. The spectral shaper is for spectrally modifying an optical property of at least some frequency components of the broadband range of frequency components such that the broadband range of frequency components is shaped producing a shaped first train of pulses to specifically probe a spectral feature of interest from a sample, and to reduce information from features that are not of interest from the sample. The modulator system is for modulating a property of at least one of the shaped first train of pulses and the second train of pulses at a modulation frequency. The optical detector is for detecting an integrated intensity of substantially all optical frequency components of a train of pulses of interest transmitted or reflected through the common focal volume. The processor is for detecting a modulation at the modulation frequency of the integrated intensity of substantially all of the optical frequency components of the train of pulses of interest due to the non-linear interaction of the shaped first train of pulses with the second train of pulses as modulated in the common focal volume, and for providing an output signal for a pixel of an image for the microscopy imaging system.

  13. Development of a superconducting transition edge thermometer for calorimetric detection of heavy ions

    Energy Technology Data Exchange (ETDEWEB)

    Meier, J; Boehmer, W; Egelhof, P; Henning, W; Kienlin, A v [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany) Mainz Univ. (Germany). Inst. fuer Physik; Shepard, K W [Argonne National Lab., IL (United States)

    1991-10-01

    A low temperature bolometer for the calorimetric detection of heavy ions was constructed and tested. An aluminium thin-film microstrip, patterned in a meander-line structure by photolithographic techniques, serves as superconducting transition edge thermometer on a sapphire absorber. A transition width {delta}T of the thermometer of the order of some mK, and a resistance of up to R{sub c} = 60 k{Omega} at the working point (T{sub c} {approx equal} 1.5 K) is achieved. In tests with {alpha}-particles signals of typically 1 V pulseheight after the preamplifier and decaytimes around hundred {mu}s were observed. For 5.5 MeV {alpha}-particles the measured energy resolution is {Delta}E = 50 keV, corresponding to a temperature resolution of about 1 {mu}K. First measurements were performed with {sup 20}Ne ions (E = 116 MeV). The dependence of the pulseheight and the FWHM on the working point were investigated and qualitatively explained. The best energy resolution was {Delta}E = 2.6 MeV; most probably the present limitations are determined by the temperature stabilization. (orig.).

  14. HARDWARE REALIZATION OF CANNY EDGE DETECTION ALGORITHM FOR UNDERWATER IMAGE SEGMENTATION USING FIELD PROGRAMMABLE GATE ARRAYS

    Directory of Open Access Journals (Sweden)

    ALEX RAJ S. M.

    2017-09-01

    Full Text Available Underwater images raise new challenges in the field of digital image processing technology in recent years because of its widespread applications. There are many tangled matters to be considered in processing of images collected from water medium due to the adverse effects imposed by the environment itself. Image segmentation is preferred as basal stage of many digital image processing techniques which distinguish multiple segments in an image and reveal the hidden crucial information required for a peculiar application. There are so many general purpose algorithms and techniques that have been developed for image segmentation. Discontinuity based segmentation are most promising approach for image segmentation, in which Canny Edge detection based segmentation is more preferred for its high level of noise immunity and ability to tackle underwater environment. Since dealing with real time underwater image segmentation algorithm, which is computationally complex enough, an efficient hardware implementation is to be considered. The FPGA based realization of the referred segmentation algorithm is presented in this paper.

  15. Non-linear effects in transition edge sensors for X-ray detection

    International Nuclear Information System (INIS)

    Bandler, S.R.; Figueroa-Feliciano, E.; Iyomoto, N.; Kelley, R.L.; Kilbourne, C.A.; Murphy, K.D.; Porter, F.S.; Saab, T.; Sadleir, J.

    2006-01-01

    In a microcalorimeter that uses a transition-edge sensor to detect energy depositions, the small signal energy resolution improves with decreasing heat capacity. This improvement remains true up to the point where non-linear and saturation effects become significant. This happens when the energy deposition causes a significant change in the sensor resistance. Not only does the signal size become a non-linear function of the energy deposited, but also the noise becomes non-stationary over the duration of the pulse. Algorithms have been developed that can calculate the optimal performance given this non-linear behavior that typically requires significant processing and calibration work-both of which are impractical for space missions. We have investigated the relative importance of the various non-linear effects, with the hope that a computationally simple transformation can overcome the largest of the non-linear and non-stationary effects, producing a highly linear 'gain' for pulse-height versus energy, and close to the best energy resolution at all energies when using a Wiener filter

  16. Edge detection using IDL for mammographic image in Medical Physics laboratory

    International Nuclear Information System (INIS)

    Wan Hazlinda Ismail; Md Saion Salikin; Asmaliza Hashim; Norriza Mohd Isa; Azuhar Ripin

    2004-01-01

    Over the decade, doctors, physicists and scientists have been using radiographic images to diagnosis patient illness as well as to study the anatomy of human body without having to cut them. Now days, in the advancement of technologies these images are available in digital form. The image data can be manipulated to determine exactly the information doctors, physicists and scientists want, which can help them in decision making when diagnosis as well as help them in understanding of the human body better. In this paper, the edge detection technique is discussed in brief which is extensive used in image y segmentation where the method is performed by finding the boundaries between objects, thus indirectly defining the object. Bennet Model DMF- 150 Mammography Machine and breast phantom model l2A with 4. 0 cm compressed thickness are employed in this study. A Vidar film digitizer is used to digitize the images. The digitized images are then manipulated by using Interactive Data language (IDL) software. Results of this study are presented in brief in this presentation. (Author)

  17. Spectral Detection of Soybean Aphid (Hemiptera: Aphididae) and Confounding Insecticide Effects in Soybean

    Science.gov (United States)

    Alves, Tavvs Micael

    Soybean aphid, Aphis glycines (Hemiptera: Aphididae) is the primary insect pest of soybean in the northcentral United States. Soybean aphid may cause stunted plants, leaf discoloration, plant death, and decrease soybean yield by 40%. Sampling plans have been developed for supporting soybean aphid management. However, growers' perception about time involved in direct insect counts has been contributing to a lower adoption of traditional pest scouting methods and may be associated with the use of prophylactic insecticide applications in soybean. Remote sensing of plant spectral (light-derived) responses to soybean aphid feeding is a promising alternative to estimate injury without direct insect counts and, thus, increase adoption and efficiency of scouting programs. This research explored the use of remote sensing of soybean reflectance for detection of soybean aphids and showed that foliar insecticides may have implications for subsequent use of soybean spectral reflectance for pest detection. (Abstract shortened by ProQuest.).

  18. Fundus auto fluorescence and spectral domain ocular coherence tomography in the early detection of chloroquine retinopathy

    OpenAIRE

    Megan B. Goodman; Ari Ziskind

    2015-01-01

    Purpose: To determine the sensitivity of spectral domain ocular coherence tomography (SD-OCT) and fundus auto fluorescence (FAF) images as a screening test to detect early changes in the retina prior to the onset of chloroquine retinopathy. Method: The study was conducted using patients taking chloroquine (CQ), referred by the Rheumatology Department to the Ophthalmology Department at Tygerberg Academic Hospital. Group A consisted of 59 patients on CQ for less than 5 years, and Group B co...

  19. A differential detection scheme of spectral shifts in long-period fiber gratings

    Science.gov (United States)

    Zhelyazkova, Katerina; Eftimov, Tinko; Smietana, Mateusz; Bock, Wojtek

    2010-10-01

    In this work we present an analysis of the response of a compact, simple and inexpensive optoelectronic sensor system intended to detect spectral shifts of a long-period fiber grating (LPG). The system makes use of a diffraction grating and a couple of receiving optical fibers that pick up signals at two different wavelengths. This differential detection system provides the same useful information from an LPG-based sensor as with a conventional laboratory system using optical spectrum analyzers for monitoring the minimum offset of LPG. The design of the fiber detection pair as a function of the parameters of the dispersion grating, the pick-up fiber and the LPG parameters, is presented in detail. Simulation of the detection system responses is presented using real from spectral shifts in nano-coated LPGs caused by the evaporation of various liquids such as water, ethanol and acetone, which are examples of corrosive, flammable and hazardous substances. Fiber optic sensors with similar detection can find applications in structural health monitoring for moisture detection, monitoring the spillage of toxic and flammable substances in industry etc.

  20. Improved target detection and bearing estimation utilizing fast orthogonal search for real-time spectral analysis

    International Nuclear Information System (INIS)

    Osman, Abdalla; El-Sheimy, Naser; Nourledin, Aboelamgd; Theriault, Jim; Campbell, Scott

    2009-01-01

    The problem of target detection and tracking in the ocean environment has attracted considerable attention due to its importance in military and civilian applications. Sonobuoys are one of the capable passive sonar systems used in underwater target detection. Target detection and bearing estimation are mainly obtained through spectral analysis of received signals. The frequency resolution introduced by current techniques is limited which affects the accuracy of target detection and bearing estimation at a relatively low signal-to-noise ratio (SNR). This research investigates the development of a bearing estimation method using fast orthogonal search (FOS) for enhanced spectral estimation. FOS is employed in this research in order to improve both target detection and bearing estimation in the case of low SNR inputs. The proposed methods were tested using simulated data developed for two different scenarios under different underwater environmental conditions. The results show that the proposed method is capable of enhancing the accuracy for target detection as well as bearing estimation especially in cases of a very low SNR

  1. Spectral methods for the detection of network community structure: a comparative analysis

    International Nuclear Information System (INIS)

    Shen, Hua-Wei; Cheng, Xue-Qi

    2010-01-01

    Spectral analysis has been successfully applied to the detection of community structure of networks, respectively being based on the adjacency matrix, the standard Laplacian matrix, the normalized Laplacian matrix, the modularity matrix, the correlation matrix and several other variants of these matrices. However, the comparison between these spectral methods is less reported. More importantly, it is still unclear which matrix is more appropriate for the detection of community structure. This paper answers the question by evaluating the effectiveness of these five matrices against benchmark networks with heterogeneous distributions of node degree and community size. Test results demonstrate that the normalized Laplacian matrix and the correlation matrix significantly outperform the other three matrices at identifying the community structure of networks. This indicates that it is crucial to take into account the heterogeneous distribution of node degree when using spectral analysis for the detection of community structure. In addition, to our surprise, the modularity matrix exhibits very similar performance to the adjacency matrix, which indicates that the modularity matrix does not gain benefits from using the configuration model as a reference network with the consideration of the node degree heterogeneity

  2. A graph signal filtering-based approach for detection of different edge types on airborne lidar data

    Science.gov (United States)

    Bayram, Eda; Vural, Elif; Alatan, Aydin

    2017-10-01

    Airborne Laser Scanning is a well-known remote sensing technology, which provides a dense and highly accurate, yet unorganized point cloud of earth surface. During the last decade, extracting information from the data generated by airborne LiDAR systems has been addressed by many studies in geo-spatial analysis and urban monitoring applications. However, the processing of LiDAR point clouds is challenging due to their irregular structure and 3D geometry. In this study, we propose a novel framework for the detection of the boundaries of an object or scene captured by LiDAR. Our approach is motivated by edge detection techniques in vision research and it is established on graph signal filtering which is an exciting and promising field of signal processing for irregular data types. Due to the convenient applicability of graph signal processing tools on unstructured point clouds, we achieve the detection of the edge points directly on 3D data by using a graph representation that is constructed exclusively to answer the requirements of the application. Moreover, considering the elevation data as the (graph) signal, we leverage aerial characteristic of the airborne LiDAR data. The proposed method can be employed both for discovering the jump edges on a segmentation problem and for exploring the crease edges on a LiDAR object on a reconstruction/modeling problem, by only adjusting the filter characteristics.

  3. A spectral method to detect community structure based on distance modularity matrix

    Science.gov (United States)

    Yang, Jin-Xuan; Zhang, Xiao-Dong

    2017-08-01

    There are many community organizations in social and biological networks. How to identify these community structure in complex networks has become a hot issue. In this paper, an algorithm to detect community structure of networks is proposed by using spectra of distance modularity matrix. The proposed algorithm focuses on the distance of vertices within communities, rather than the most weakly connected vertex pairs or number of edges between communities. The experimental results show that our method achieves better effectiveness to identify community structure for a variety of real-world networks and computer generated networks with a little more time-consumption.

  4. Improvement of LOD in Fluorescence Detection with Spectrally Nonuniform Background by Optimization of Emission Filtering.

    Science.gov (United States)

    Galievsky, Victor A; Stasheuski, Alexander S; Krylov, Sergey N

    2017-10-17

    The limit-of-detection (LOD) in analytical instruments with fluorescence detection can be improved by reducing noise of optical background. Efficiently reducing optical background noise in systems with spectrally nonuniform background requires complex optimization of an emission filter-the main element of spectral filtration. Here, we introduce a filter-optimization method, which utilizes an expression for the signal-to-noise ratio (SNR) as a function of (i) all noise components (dark, shot, and flicker), (ii) emission spectrum of the analyte, (iii) emission spectrum of the optical background, and (iv) transmittance spectrum of the emission filter. In essence, the noise components and the emission spectra are determined experimentally and substituted into the expression. This leaves a single variable-the transmittance spectrum of the filter-which is optimized numerically by maximizing SNR. Maximizing SNR provides an accurate way of filter optimization, while a previously used approach based on maximizing a signal-to-background ratio (SBR) is the approximation that can lead to much poorer LOD specifically in detection of fluorescently labeled biomolecules. The proposed filter-optimization method will be an indispensable tool for developing new and improving existing fluorescence-detection systems aiming at ultimately low LOD.

  5. Development of a modular directional and spectral neutron detection system using solid-state detectors

    Energy Technology Data Exchange (ETDEWEB)

    Weltz, A., E-mail: weltza3@gmail.com; Torres, B.; McElwain, L.; Dahal, R.; Huang, J.; Bhat, I.; Lu, J.; Danon, Y.

    2015-08-21

    A detection system using room-temperature, microstructured solid-state thermal neutron detectors with very low leakage current has been developed at Rensselaer Polytechnic Institute (RPI) with the ability to provide positional and spectral information about an unknown neutron source. The Directional and Spectral Neutron Detection System (DSNDS) utilizes a set of small-but-scalable, zero-bias solid-state thermal neutron detectors which have demonstrated high thermal neutron efficiency and adequate gamma insensitivity. The DSNDS can gather spectral information about an unknown neutron source with a relatively small number of detectors, simplifying the detector electronics and minimizing cost; however, the DSNDS is modular in design, providing the capability to increase the detection efficiency and angular resolution. The system used in this paper was comprised of a stack of five high-density polyethylene (HDPE) disks with a thickness of 5 cm and a diameter of 30 cm, the middle disk containing 16 detectors positioned as one internal (moderated) and one external (unmoderated) ring of solid-state neutron detectors. These two detector rings provide the ability to determine the directionality of a neutron source. The system gathers spectral information about a neutron source in two ways: by measuring the relative responses of the internal ring of detectors as well as measuring the ratio of the internal-to-external detector responses. Experiments were performed with variable neutron spectra: a {sup 252}Cf spontaneous fission neutron source which was HDPE moderated, HDPE reflected, lead (Pb) shielded, and bare in order to benchmark the system for spectral sensitivity. Simulations were performed in order to characterize the neutron spectra corresponding to each of the source configurations and showed agreement with experimental measurements. The DSNDS demonstrates the ability to determine the relative angle of the source and the hardness of the neutron spectrum. By using the

  6. Spectrally efficient polarization multiplexed direct-detection OFDM system without frequency gap.

    Science.gov (United States)

    Wei, Chia-Chien; Zeng, Wei-Siang; Lin, Chun-Ting

    2016-01-25

    We experimentally demonstrate a spectrally efficient direct-detection orthogonal frequency-division multiplexing (DD-OFDM) system. In addition to polarization-division multiplexing, removing the frequency gap further improves the spectral efficiency of the OFDM system. The frequency gap between a reference carrier and OFDM subcarriers avoids subcarrier-to-subcarrier beating interference (SSBI) in traditional DD-OFDM systems. Without dynamic polarization control, the resulting interference after square-law direct detection in the proposed gap-less system is polarization-dependent and composed of linear inter-carrier interference (ICI) and nonlinear SSBI. Thus, this work proposes an iterative multiple-input multiple-output detection scheme to remove the mixed polarization-dependent interference. Compared to the previous scheme, which only removes ICI, the proposed scheme can further eliminate SSBI to achieve the improvement of ∼ 7 dB in signal-to-noise ratio. Without the need for polarization control, we successfully utilize 7-GHz bandwidth to transmit a 39.5-Gbps polarization multiplexed OFDM signal over 100 km.

  7. Spectral encoded optical label detection for dynamic routing of impulse radio ultra-wideband signals in metro-access networks

    DEFF Research Database (Denmark)

    Osadchiy, Alexey Vladimirovich; Yu, Xianbin; Yin, Xiaoli

    2010-01-01

    In this paper we propose and experimentally demonstrate the principle of coherent label detection for dynamic routing of wavelength division multiplexed impulse radio ultra-wideband signals by using four-tone spectral amplitude coded labels.......In this paper we propose and experimentally demonstrate the principle of coherent label detection for dynamic routing of wavelength division multiplexed impulse radio ultra-wideband signals by using four-tone spectral amplitude coded labels....

  8. A spectrally efficient detect-and-forward scheme with two-tier adaptive cooperation

    KAUST Repository

    Benjillali, Mustapha

    2011-09-01

    We propose a simple relay-based adaptive cooperation scheme to improve the spectral efficiency of "Detect-and-Forward" (DetF) half-duplex relaying in fading channels. In a new common framework, we show that the proposed scheme offers considerable gainsin terms of the achievable information ratescompared to conventional DetF relaying schemes for both orthogonal and non-orthogonal source/relay transmissions. The analysis leads on to a general adaptive cooperation strategy based on the maximization of information rates at the destination which needs to observe only the average signal-to-noise ratios of the links. © 2006 IEEE.

  9. Visual perception enhancement for detection of cancerous oral tissue by multi-spectral imaging

    International Nuclear Information System (INIS)

    Wang, Hsiang-Chen; Tsai, Meng-Tsan; Chiang, Chun-Ping

    2013-01-01

    Color reproduction systems based on the multi-spectral imaging technique (MSI) for both directly estimating reflection spectra and direct visualization of oral tissues using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectral differences between pre-cancerous and normal oral mucosal tissues were calculated at three time points during 5-aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. To check the successful treatment of oral cancer with ALA-PDT, oral cavity images by swept source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduce images under different light sources. For pre-cancerous detection, the oral images after the second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with a CCT of about 4500 K was found to have the best ability to enhance the color difference between pre-cancerous and normal oral mucosal tissues in the oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aid patients in receiving early treatment. (paper)

  10. Detection of the power lines in UAV remote sensed images using spectral-spatial methods.

    Science.gov (United States)

    Bhola, Rishav; Krishna, Nandigam Hari; Ramesh, K N; Senthilnath, J; Anand, Gautham

    2018-01-15

    In this paper, detection of the power lines on images acquired by Unmanned Aerial Vehicle (UAV) based remote sensing is carried out using spectral-spatial methods. Spectral clustering was performed using Kmeans and Expectation Maximization (EM) algorithm to classify the pixels into the power lines and non-power lines. The spectral clustering methods used in this study are parametric in nature, to automate the number of clusters Davies-Bouldin index (DBI) is used. The UAV remote sensed image is clustered into the number of clusters determined by DBI. The k clustered image is merged into 2 clusters (power lines and non-power lines). Further, spatial segmentation was performed using morphological and geometric operations, to eliminate the non-power line regions. In this study, UAV images acquired at different altitudes and angles were analyzed to validate the robustness of the proposed method. It was observed that the EM with spatial segmentation (EM-Seg) performed better than the Kmeans with spatial segmentation (Kmeans-Seg) on most of the UAV images. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Frequency interleaving towards spectrally efficient directly detected optical OFDM for next-generation optical access networks.

    Science.gov (United States)

    Mehedy, Lenin; Bakaul, Masuduzzaman; Nirmalathas, Ampalavanapillai

    2010-10-25

    In this paper, we theoretically analyze and demonstrate that spectral efficiency of a conventional direct detection based optical OFDM system (DDO-OFDM) can be improved significantly using frequency interleaving of adjacent DDO-OFDM channels where OFDM signal band of one channel occupies the spectral gap of other channel and vice versa. We show that, at optimum operating condition, the proposed technique can effectively improve the spectral efficiency of the conventional DDO-OFDM system as much as 50%. We also show that such a frequency interleaved DDO-OFDM system, with a bit rate of 48 Gb/s within 25 GHz bandwidth, achieves sufficient power budget after transmission over 25 km single mode fiber to be used in next-generation time-division-multiplexed passive optical networks (TDM-PON). Moreover, by applying 64- quadrature amplitude modulation (QAM), the system can be further scaled up to 96 Gb/s with a power budget sufficient for 1:16 split TDM-PON.

  12. Visual perception enhancement for detection of cancerous oral tissue by multi-spectral imaging

    Science.gov (United States)

    Wang, Hsiang-Chen; Tsai, Meng-Tsan; Chiang, Chun-Ping

    2013-05-01

    Color reproduction systems based on the multi-spectral imaging technique (MSI) for both directly estimating reflection spectra and direct visualization of oral tissues using various light sources are proposed. Images from three oral cancer patients were taken as the experimental samples, and spectral differences between pre-cancerous and normal oral mucosal tissues were calculated at three time points during 5-aminolevulinic acid photodynamic therapy (ALA-PDT) to analyze whether they were consistent with disease processes. To check the successful treatment of oral cancer with ALA-PDT, oral cavity images by swept source optical coherence tomography (SS-OCT) are demonstrated. This system can also reproduce images under different light sources. For pre-cancerous detection, the oral images after the second ALA-PDT are assigned as the target samples. By using RGB LEDs with various correlated color temperatures (CCTs) for color difference comparison, the light source with a CCT of about 4500 K was found to have the best ability to enhance the color difference between pre-cancerous and normal oral mucosal tissues in the oral cavity. Compared with the fluorescent lighting commonly used today, the color difference can be improved by 39.2% from 16.5270 to 23.0023. Hence, this light source and spectral analysis increase the efficiency of the medical diagnosis of oral cancer and aid patients in receiving early treatment.

  13. A Simulated Annealing Algorithm for Maximum Common Edge Subgraph Detection in Biological Networks

    DEFF Research Database (Denmark)

    Larsen, Simon; Alkærsig, Frederik G.; Ditzel, Henrik

    2016-01-01

    Network alignment is a challenging computational problem that identifies node or edge mappings between two or more networks, with the aim to unravel common patterns among them. Pairwise network alignment is already intractable, making multiple network comparison even more difficult. Here, we intr...

  14. A simplified implementation of edge detection in MATLAB is faster and more sensitive than fast fourier transform for actin fiber alignment quantification.

    Science.gov (United States)

    Kemeny, Steven Frank; Clyne, Alisa Morss

    2011-04-01

    Fiber alignment plays a critical role in the structure and function of cells and tissues. While fiber alignment quantification is important to experimental analysis and several different methods for quantifying fiber alignment exist, many studies focus on qualitative rather than quantitative analysis perhaps due to the complexity of current fiber alignment methods. Speed and sensitivity were compared in edge detection and fast Fourier transform (FFT) for measuring actin fiber alignment in cells exposed to shear stress. While edge detection using matrix multiplication was consistently more sensitive than FFT, image processing time was significantly longer. However, when MATLAB functions were used to implement edge detection, MATLAB's efficient element-by-element calculations and fast filtering techniques reduced computation cost 100 times compared to the matrix multiplication edge detection method. The new computation time was comparable to the FFT method, and MATLAB edge detection produced well-distributed fiber angle distributions that statistically distinguished aligned and unaligned fibers in half as many sample images. When the FFT sensitivity was improved by dividing images into smaller subsections, processing time grew larger than the time required for MATLAB edge detection. Implementation of edge detection in MATLAB is simpler, faster, and more sensitive than FFT for fiber alignment quantification.

  15. Coherent spectral amplitude coded label detection for DQPSK payload signals in packet-switched metropolitan area networks

    DEFF Research Database (Denmark)

    Osadchiy, Alexey Vladimirovich; Guerrero Gonzalez, Neil; Jensen, Jesper Bevensee

    2011-01-01

    We report on an experimental demonstration of a frequency swept local oscillator-based spectral amplitude coding (SAC) label detection for DQPSK signals after 40km of fiber transmission. Label detection was performed for a 10.7Gbaud DQPSK signal labeled with a SAC label composed of four......-frequency tones with 500MHz spectral separation. Successful label detection and recognition is achieved with the aid of digital signal processing that allows for substantial reduction of the complexity of the detection optical front-end....

  16. Intercomparison of auto- and cross-power spectral density surveillance systems for sodium boiling detection in fast reactors

    International Nuclear Information System (INIS)

    Ehrhardt, J.

    1979-01-01

    Theoretical and experimental investigations on detection systems for small narrow-band components in noise signals were conducted. These detectionn systems are based on the continuous surveillance of the power spectral density for characteristic peaks. Detection sensitivity for auto- and cross-correlation measurements was computed for signals with normally distributed amplitudes in dependence of signal coherence. The derived detection criteria allowed the comparison of auto- and cross-power spectral density surveillance. Theoretical results were confirmed in a number of experimental parameter studies. Special theoretical investigations were done for the optimal detection of local sodium boiling in liquid-metal fast breeder reactors

  17. An adaptive demodulation approach for bearing fault detection based on adaptive wavelet filtering and spectral subtraction

    Science.gov (United States)

    Zhang, Yan; Tang, Baoping; Liu, Ziran; Chen, Rengxiang

    2016-02-01

    Fault diagnosis of rolling element bearings is important for improving mechanical system reliability and performance. Vibration signals contain a wealth of complex information useful for state monitoring and fault diagnosis. However, any fault-related impulses in the original signal are often severely tainted by various noises and the interfering vibrations caused by other machine elements. Narrow-band amplitude demodulation has been an effective technique to detect bearing faults by identifying bearing fault characteristic frequencies. To achieve this, the key step is to remove the corrupting noise and interference, and to enhance the weak signatures of the bearing fault. In this paper, a new method based on adaptive wavelet filtering and spectral subtraction is proposed for fault diagnosis in bearings. First, to eliminate the frequency associated with interfering vibrations, the vibration signal is bandpass filtered with a Morlet wavelet filter whose parameters (i.e. center frequency and bandwidth) are selected in separate steps. An alternative and efficient method of determining the center frequency is proposed that utilizes the statistical information contained in the production functions (PFs). The bandwidth parameter is optimized using a local ‘greedy’ scheme along with Shannon wavelet entropy criterion. Then, to further reduce the residual in-band noise in the filtered signal, a spectral subtraction procedure is elaborated after wavelet filtering. Instead of resorting to a reference signal as in the majority of papers in the literature, the new method estimates the power spectral density of the in-band noise from the associated PF. The effectiveness of the proposed method is validated using simulated data, test rig data, and vibration data recorded from the transmission system of a helicopter. The experimental results and comparisons with other methods indicate that the proposed method is an effective approach to detecting the fault-related impulses

  18. An adaptive demodulation approach for bearing fault detection based on adaptive wavelet filtering and spectral subtraction

    International Nuclear Information System (INIS)

    Zhang, Yan; Tang, Baoping; Chen, Rengxiang; Liu, Ziran

    2016-01-01

    Fault diagnosis of rolling element bearings is important for improving mechanical system reliability and performance. Vibration signals contain a wealth of complex information useful for state monitoring and fault diagnosis. However, any fault-related impulses in the original signal are often severely tainted by various noises and the interfering vibrations caused by other machine elements. Narrow-band amplitude demodulation has been an effective technique to detect bearing faults by identifying bearing fault characteristic frequencies. To achieve this, the key step is to remove the corrupting noise and interference, and to enhance the weak signatures of the bearing fault. In this paper, a new method based on adaptive wavelet filtering and spectral subtraction is proposed for fault diagnosis in bearings. First, to eliminate the frequency associated with interfering vibrations, the vibration signal is bandpass filtered with a Morlet wavelet filter whose parameters (i.e. center frequency and bandwidth) are selected in separate steps. An alternative and efficient method of determining the center frequency is proposed that utilizes the statistical information contained in the production functions (PFs). The bandwidth parameter is optimized using a local ‘greedy’ scheme along with Shannon wavelet entropy criterion. Then, to further reduce the residual in-band noise in the filtered signal, a spectral subtraction procedure is elaborated after wavelet filtering. Instead of resorting to a reference signal as in the majority of papers in the literature, the new method estimates the power spectral density of the in-band noise from the associated PF. The effectiveness of the proposed method is validated using simulated data, test rig data, and vibration data recorded from the transmission system of a helicopter. The experimental results and comparisons with other methods indicate that the proposed method is an effective approach to detecting the fault-related impulses

  19. Fluorescence hyper-spectral imaging to detecting faecal contamination on fresh tomatoes

    Directory of Open Access Journals (Sweden)

    Roberto Romaniello

    2016-03-01

    Full Text Available Faecal contamination of fresh fruits represents a severe danger for human health. Thus some techniques based on microbiological testing were developed to individuate faecal contaminants but those tests do not results efficient because their non-applicability on overall vegetable unity. In this work a methodology based on hyper-spectral fluorescence imaging was developed and tested to detecting faecal contamination on fresh tomatoes. Two image-processing methods were performed to maximise the contrast between the faecal contaminant and tomatoes skin: principal component analysis and band image ratio (BRI. The BRI method allows classifying correctly 70% of contaminated area, with no false-positives in all examined cases. Thus, the developed methodology can be employed for a fast and effective detection of faecal contamination on fresh tomatoes.

  20. Spectral analysis to detection of short circuit fault of solar photovoltaic modules in strings

    International Nuclear Information System (INIS)

    Sevilla-Camacho, P.Y.; Robles-Ocampo, J.B.; Zuñiga-Reyes, Marco A.

    2017-01-01

    This research work presents a method to detect the number of short circuit faulted solar photovoltaic modules in strings of a photovoltaic system by taking into account speed, safety, and non-use of sensors and specialized and expensive equipment. The method consists on apply the spectral analysis and statistical techniques to the alternating current output voltage of a string and detect the number of failed modules through the changes in the amplitude of the component frequency of 12 kHz. For that, the analyzed string is disconnected of the array; and a small pulsed voltage signal of frequency of 12 kHz introduces him under dark condition and controlled temperature. Previous to the analysis, the signal is analogic filtered in order to reduce the direct current signal component. The spectral analysis technique used is the Fast Fourier Transform. The obtained experimental results were validated through simulation of the alternating current equivalent circuit of a solar cell. In all experimental and simulated test, the method allowed to identify correctly the number of photovoltaic modules with short circuit in the analyzed string. (author)

  1. Detection of illicit drugs with the technique of spectral fluorescence signatures (SFS)

    Science.gov (United States)

    Poryvkina, Larisa; Babichenko, Sergey

    2010-10-01

    The SFS technology has already proved its analytical capabilities in a variety of industrial and environmental tasks. Recently it has been introduced for forensic applications. The key features of the SFS method - measuring a 3-dimensional spectrum of fluorescence of the sample (intensity versus excitation and emission wavelengths) with following recognition of specific spectral patterns of SFS responsible for individual drugs - provide an effective tool for the analysis of untreated seized samples, without any separation of the substance of interest from its mixture with accompanying cutting agents and diluents as a preparatory step. In such approach the chemical analysis of the sample is substituted by the analysis of SFS matrix visualized as an optical image. The SFS technology of drug detection is realized by NarTest® NTX2000 analyzer, compact device intended to measure suspicious samples in liquid, solid and powder forms. It simplifies the detection process due to fully automated procedures of SFS measuring and integrated expert system for recognition of spectral patterns. Presently the expert system of NTX2000 is able to detect marijuana, cocaine, heroin, MDMA, amphetamine and methamphetamine with the detection limit down to 5% of the drug concentration in various mixtures. The numerous tests with street samples confirmed that the use of SFS method provides reliable results with high sensitivity and selectivity for identification of drugs of abuse. More than 3000 street samples of the aforesaid drugs were analyzed with NTX2000 during validation process, and the correspondence of SFS results and conclusions of standard forensic analyses with GC/MS techniques was in 99.4% cases.

  2. Improved CORF model of simple cell combined with non-classical receptive field and its application on edge detection

    Science.gov (United States)

    Sun, Xiao; Chai, Guobei; Liu, Wei; Bao, Wenzhuo; Zhao, Xiaoning; Ming, Delie

    2018-02-01

    Simple cells in primary visual cortex are believed to extract local edge information from a visual scene. In this paper, inspired by different receptive field properties and visual information flow paths of neurons, an improved Combination of Receptive Fields (CORF) model combined with non-classical receptive fields was proposed to simulate the responses of simple cell's receptive fields. Compared to the classical model, the proposed model is able to better imitate simple cell's physiologic structure with consideration of facilitation and suppression of non-classical receptive fields. And on this base, an edge detection algorithm as an application of the improved CORF model was proposed. Experimental results validate the robustness of the proposed algorithm to noise and background interference.

  3. A Hybrid Spectral Clustering and Deep Neural Network Ensemble Algorithm for Intrusion Detection in Sensor Networks.

    Science.gov (United States)

    Ma, Tao; Wang, Fen; Cheng, Jianjun; Yu, Yang; Chen, Xiaoyun

    2016-10-13

    The development of intrusion detection systems (IDS) that are adapted to allow routers and network defence systems to detect malicious network traffic disguised as network protocols or normal access is a critical challenge. This paper proposes a novel approach called SCDNN, which combines spectral clustering (SC) and deep neural network (DNN) algorithms. First, the dataset is divided into k subsets based on sample similarity using cluster centres, as in SC. Next, the distance between data points in a testing set and the training set is measured based on similarity features and is fed into the deep neural network algorithm for intrusion detection. Six KDD-Cup99 and NSL-KDD datasets and a sensor network dataset were employed to test the performance of the model. These experimental results indicate that the SCDNN classifier not only performs better than backpropagation neural network (BPNN), support vector machine (SVM), random forest (RF) and Bayes tree models in detection accuracy and the types of abnormal attacks found. It also provides an effective tool of study and analysis of intrusion detection in large networks.

  4. Automated Fovea Detection in Spectral Domain Optical Coherence Tomography Scans of Exudative Macular Disease

    Directory of Open Access Journals (Sweden)

    Jing Wu

    2016-01-01

    Full Text Available In macular spectral domain optical coherence tomography (SD-OCT volumes, detection of the foveal center is required for accurate and reproducible follow-up studies, structure function correlation, and measurement grid positioning. However, disease can cause severe obscuring or deformation of the fovea, thus presenting a major challenge in automated detection. We propose a fully automated fovea detection algorithm to extract the fovea position in SD-OCT volumes of eyes with exudative maculopathy. The fovea is classified into 3 main appearances to both specify the detection algorithm used and reduce computational complexity. Based on foveal type classification, the fovea position is computed based on retinal nerve fiber layer thickness. Mean absolute distance between system and clinical expert annotated fovea positions from a dataset comprised of 240 SD-OCT volumes was 162.3 µm in cystoid macular edema and 262 µm in nAMD. The presented method has cross-vendor functionality, while demonstrating accurate and reliable performance close to typical expert interobserver agreement. The automatically detected fovea positions may be used as landmarks for intra- and cross-patient registration and to create a joint reference frame for extraction of spatiotemporal features in “big data.” Furthermore, reliable analyses of retinal thickness, as well as retinal structure function correlation, may be facilitated.

  5. BUILDING EDGE DETECTION USING SMALL-FOOTPRINT AIRBORNE FULL-WAVEFORM LIDAR DATA

    Directory of Open Access Journals (Sweden)

    J.-C. Michelin

    2012-07-01

    Full Text Available The full-waveform lidar technology allows a complete access to the information related to the emitted and backscattered laser signals. Although most of the common applications of full-waveform lidar are currently dedicated to the study of forested areas, some recent studies have shown that airborne full-waveform data is relevant for urban area analysis. We extend the field to pattern recognition with a focus on retrieval. Our proposed approach combines two steps. In a first time, building edges are coarsely extracted. Then, a physical model based on the lidar equation is used to retrieve a more accurate position of the estimated edge than the size of the lidar footprint. Another consequence is the estimation of more accurate planimetric positions of the extracted echoes.

  6. Spectrally resolved detection of sodium in the atmosphere of HD 189733b with the HARPS spectrograph

    Science.gov (United States)

    Wyttenbach, A.; Ehrenreich, D.; Lovis, C.; Udry, S.; Pepe, F.

    2015-05-01

    Context. Atmospheric properties of exoplanets can be constrained with transit spectroscopy. At low spectral resolution, this technique is limited by the presence of clouds. The signature of atomic sodium (Na i), known to be present above the clouds, is a powerful probe of the upper atmosphere, where it can be best detected and characterized at high spectral resolution. Aims: Our goal is to obtain a high-resolution transit spectrum of HD 189733b in the region around the resonance doublet of Na i at 589 nm, to characterize the absorption signature that was previously detected from space at low resolution. Methods: We analyzed archival transit data of HD 189733b obtained with the HARPS spectrograph (ℛ = 115 000) at the ESO 3.6-m telescope. We performed differential spectroscopy to retrieve the transit spectrum and light curve of the planet, implementing corrections for telluric contamination and planetary orbital motion. We compared our results to synthetic transit spectra calculated from isothermal models of the planetary atmosphere. Results: We spectrally resolve the Na i D doublet and measure line contrasts of 0.64 ± 0.07% (D2) and 0.40 ± 0.07% (D1) and FWHMs of 0.52 ± 0.08 Å. This corresponds to a detection at the 10σ level of excess of absorption of 0.32 ± 0.03% in a passband of 2 × 0.75 Å centered on each line. We derive temperatures of 2600 ± 600 K and 3270 ± 330 K at altitudes of 9800 ± 2800 and 12 700 ± 2600 km in the Na i D1 and D2 line cores, respectively. We measure a temperature gradient of ~0.2 K km-1 in the region where the sodium absorption dominates the haze absorption from a comparison with theoretical models. We also detect a blueshift of 0.16 ± 0.04 Å (4σ) in the line positions. This blueshift may be the result of winds blowing at 8 ± 2 km s-1 in the upper layers of the atmosphere. Conclusions: We demonstrate the relevance of studying exoplanet atmospheres with high-resolution spectrographs mounted on 4-m-class telescopes. Our

  7. Detection of Extraterrestrial Civilizations via the Spectral Signature of Advanced Interstellar Spacecraft

    Science.gov (United States)

    Zubrin, Robert

    1994-07-01

    This paper examines the possibility of detecting extraterrestrial civilizations by means of searching for the spectral signature of their interstellar transportation systems. The advantage of such an approach is that the characteristic power levels associated with interstellar transportation systems are many orders of magnitude greater than those required for communication, and so the signal strength may be much greater. Furthermore, unlike communication which is governed by a fairly arbitrary selection of technology and mutually agreed upon conventions, interstellar transportation systems are governed much more stringently by the laws of physics. For purposes of the present analysis we consider 4 methods of interstellar propulsion, the principles of which are fairly well understood. These are anti-matter rockets, fusion rockets, fission rockets, all of which can be used to either accelerate or decelerate a spacecraft, and magnetic sails, which can be used to decelerate a spacecraft by creating drag against the interstellar medium. The types of radiation emitted by each of these propulsion systems is described, and the signal strength for starships of a characteristic mass of 1 million tonnes traveling at speeds and acceleration levels characteristic of the various propulsion systems is estimated. It is shown that for the power level of ships considered, the high energy gamma radiation emitted by the anti-matter, fusion and fission propulsion systems would be undetectable at interstellar distances. Better opportunities for detection would be the bremsstrahlung radiation from the plasma confinement systems of fusion devices, which might be detectable at distances of about 1 light year, and visible light emitted from the radiators of anti-matter driven photon rocket, which might be detectable by the Hubble Space Telescope at a distance of several hundred light years provided the rocket nozzle is oriented towards the Earth. The most detectable form of starship

  8. Detection of embedded radiation sources using temporal variation of gamma spectral data.

    Energy Technology Data Exchange (ETDEWEB)

    Shokair, Isaac R.

    2011-09-01

    Conventional full spectrum gamma spectroscopic analysis has the objective of quantitative identification of all the isotopes present in a measurement. For low energy resolution detectors, when photopeaks alone are not sufficient for complete isotopic identification, such analysis requires template spectra for all the isotopes present in the measurement. When many isotopes are present it is difficult to make the correct identification and this process often requires many trial solutions by highly skilled spectroscopists. This report investigates the potential of a new analysis method which uses spatial/temporal information from multiple low energy resolution measurements to test the hypothesis of the presence of a target spectrum of interest in these measurements without the need to identify all the other isotopes present. This method is referred to as targeted principal component analysis (TPCA). For radiation portal monitor applications, multiple measurements of gamma spectra are taken at equally spaced time increments as a vehicle passes through the portal and the TPCA method is directly applicable to this type of measurement. In this report we describe the method and investigate its application to the problem of detection of a radioactive localized source that is embedded in a distributed source in the presence of an ambient background. Examples using simulated spectral measurements indicate that this method works very well and has the potential for automated analysis for RPM applications. This method is also expected to work well for isotopic detection in the presence of spectrally and spatially varying backgrounds as a result of vehicle-induced background suppression. Further work is needed to include effects of shielding, to understand detection limits, setting of thresholds, and to estimate false positive probability.

  9. Breath Analysis Using Laser Spectroscopic Techniques: Breath Biomarkers, Spectral Fingerprints, and Detection Limits

    Directory of Open Access Journals (Sweden)

    Peeyush Sahay

    2009-10-01

    Full Text Available Breath analysis, a promising new field of medicine and medical instrumentation, potentially offers noninvasive, real-time, and point-of-care (POC disease diagnostics and metabolic status monitoring. Numerous breath biomarkers have been detected and quantified so far by using the GC-MS technique. Recent advances in laser spectroscopic techniques and laser sources have driven breath analysis to new heights, moving from laboratory research to commercial reality. Laser spectroscopic detection techniques not only have high-sensitivity and high-selectivity, as equivalently offered by the MS-based techniques, but also have the advantageous features of near real-time response, low instrument costs, and POC function. Of the approximately 35 established breath biomarkers, such as acetone, ammonia, carbon dioxide, ethane, methane, and nitric oxide, 14 species in exhaled human breath have been analyzed by high-sensitivity laser spectroscopic techniques, namely, tunable diode laser absorption spectroscopy (TDLAS, cavity ringdown spectroscopy (CRDS, integrated cavity output spectroscopy (ICOS, cavity enhanced absorption spectroscopy (CEAS, cavity leak-out spectroscopy (CALOS, photoacoustic spectroscopy (PAS, quartz-enhanced photoacoustic spectroscopy (QEPAS, and optical frequency comb cavity-enhanced absorption spectroscopy (OFC-CEAS. Spectral fingerprints of the measured biomarkers span from the UV to the mid-IR spectral regions and the detection limits achieved by the laser techniques range from parts per million to parts per billion levels. Sensors using the laser spectroscopic techniques for a few breath biomarkers, e.g., carbon dioxide, nitric oxide, etc. are commercially available. This review presents an update on the latest developments in laser-based breath analysis.

  10. Detection of small surface vessels in near, medium, and far infrared spectral bands

    Science.gov (United States)

    Dulski, R.; Milewski, S.; Kastek, M.; Trzaskawka, P.; Szustakowski, M.; Ciurapinski, W.; Zyczkowski, M.

    2011-11-01

    Protection of naval bases and harbors requires close co-operation between security and access control systems covering land areas and those monitoring sea approach routes. The typical location of naval bases and harbors - usually next to a large city - makes it difficult to detect and identify a threat in the dense regular traffic of various sea vessels (i.e. merchant ships, fishing boats, tourist ships). Due to the properties of vessel control systems, such as AIS (Automatic Identification System), and the effectiveness of radar and optoelectronic systems against different targets it seems that fast motor boats called RIB (Rigid Inflatable Boat) could be the most serious threat to ships and harbor infrastructure. In the paper the process and conditions for the detection and identification of high-speed boats in the areas of ports and naval bases in the near, medium and far infrared is presented. Based on the results of measurements and recorded thermal images the actual temperature contrast delta T (RIB / sea) will be determined, which will further allow to specify the theoretical ranges of detection and identification of the RIB-type targets for an operating security system. The data will also help to determine the possible advantages of image fusion where the component images are taken in different spectral ranges. This will increase the probability of identifying the object by the multi-sensor security system equipped additionally with the appropriate algorithms for detecting, tracking and performing the fusion of images from the visible and infrared cameras.

  11. On the detection of corrosion pit interactions using two-dimensional spectral analysis

    International Nuclear Information System (INIS)

    Jarrah, Adil; Nianga, Jean-Marie; Iost, Alain; Guillemot, Gildas; Najjar, Denis

    2010-01-01

    A statistical methodology for detecting pits interactions based on a two-dimensional spectral analysis is presented. This method can be used as a tool for the exploratory analysis of spatial point patterns and can be advanced as an alternative of classical methods based on distance. One of the major advantages of the spectral analysis approach over the use of classical methods is its ability to reveal more details about the spatial structure like the scale for which pits corrosion can be considered as independent. Furthermore, directional components of pattern can be investigated. The method is validated in a first time using numerical simulations on random, regular and aggregated structures. The density of pits, used in the numerical simulations, corresponds to that assessed from a corroded aluminium sheet. In a second time, this method is applied to verify the independence of the corrosion pits observed on the aforementioned aluminium sheet before applying the Gumbel theory to determine the maximum pit depth. Indeed, the property of independence is a prerequisite of the Gumbel theory which is one of the most frequently used in the field of safety and reliability.

  12. Terahertz spectral signatures :measurement and detection LDRD project 86361 final report.

    Energy Technology Data Exchange (ETDEWEB)

    Wanke, Michael Clement; Brener, Igal; Lee, Mark

    2005-11-01

    LDRD Project 86361 provided support to upgrade the chemical and material spectral signature measurement and detection capabilities of Sandia National Laboratories using the terahertz (THz) portion of the electromagnetic spectrum, which includes frequencies between 0.1 to 10 THz. Under this project, a THz time-domain spectrometer was completed. This instrument measures sample absorption spectra coherently, obtaining both magnitude and phase of the absorption signal, and has shown an operating signal-to-noise ratio of 10{sub 4}. Additionally, various gas cells and a reflectometer were added to an existing high-resolution THz Fourier transform spectrometer, which greatly extend the functionality of this spectrometer. Finally, preliminary efforts to design an integrated THz transceiver based on a quantum cascade laser were begun.

  13. FRB121102: First detection across 5 - 8 GHz and spectral properties from the Breakthrough Listen instrument

    Science.gov (United States)

    Gajjar, Vishal; Siemion, Andrew; MacMohan, David; Croft, Steve; Hellbourg, Greg; Isaacson, Howard; Enriquez, J. Emilio; Price, Daniel; Lebofsky, Matt; De Boer, David; Werthimer, Dan; Hickish, Jack; Brinkman, Casey; Chatterjee, Shami; Ransom, Scott M.; Law, Casey; Hessels, Jason W. T.; Cordes, Jim; Spitler, Laura; Lynch, Ryan; McLaughlin, Maura; Scholz, Paul; Marcote, Benito; Bower, Geoffrey C.; Tendulkar, Shriharsh

    2018-01-01

    Fast Radio Bursts (FRBs) are some of the most energetic and enigmatic events in the Universe. The origin of these sources is among the most challenging questions of modern-day astrophysics. Thus, it is imperative to understand the properties of these bursts across a range of radio frequencies. Among the known FRBs, FRB121102 is the only source known to show repeated bursts [Spitler et al., Nature, 531, 7593 202-205, 2016], which can allow a detailed investigation of various origin models. In August 2017, we initiated a campaign observing FRB 121102 using the Breakthrough Listen Digital Backend with the C-band receiver at the Robert C. Byrd Green Bank Telescope (GBT). We recorded baseband voltage data across 5.4 GHz of bandwidth, completely covering the C-band receiver's nominal 4-8 GHz band [MacMahon et al. arXiv:1707.06024v2]. The recorded data were searched for dispersed pulses consistent with the known dispersion measure of FRB 121102 (557 pc cm-3) using high-speed GPU software tools. We detected 21 bursts above our detection threshold of 6 sigmas in the first 60-minutes, out of which 18 occurred in the first 30-minutes only. To our knowledge, this is the highest event rate seen for FRB121102 at any observing frequency. These observations are the highest frequency and widest bandwidth detection of bursts from FRB 121102 (or any other FRB) obtained to-date. We note that individual bursts show marked changes in spectral extent ranging from hundreds of MHz to several GHz. We have used high frequency dynamic spectra of these bursts to estimate the characteristic scintillation bandwidth and correlation time-scale. We also found distinctive temporal structures, separated by a few milliseconds, in three of the strongest bursts, with each sub-structure exhibiting varied spectral features. We will discuss our findings and how these detections of FRB 121102 around 8 GHz opens up a new regime in scrutinizing various origin models. We will also highlight the unique

  14. Field programmable gate array based hardware implementation of a gradient filter for edge detection in colour images with subpixel precision

    International Nuclear Information System (INIS)

    Schellhorn, M; Rosenberger, M; Correns, M; Blau, M; Goepfert, A; Rueckwardt, M; Linss, G

    2010-01-01

    Within the field of industrial image processing the use of colour cameras becomes ever more common. Increasingly the established black and white cameras are replaced by economical single-chip colour cameras with Bayer pattern. The use of the additional colour information is particularly important for recognition or inspection. Become interesting however also for the geometric metrology, if measuring tasks can be solved more robust or more exactly. However only few suitable algorithms are available, in order to detect edges with the necessary precision. All attempts require however additional computation expenditure. On the basis of a new filter for edge detection in colour images with subpixel precision, the implementation on a pre-processing hardware platform is presented. Hardware implemented filters offer the advantage that they can be used easily with existing measuring software, since after the filtering a single channel image is present, which unites the information of all colour channels. Advanced field programmable gate arrays represent an ideal platform for the parallel processing of multiple channels. The effective implementation presupposes however a high programming expenditure. On the example of the colour filter implementation, arising problems are analyzed and the chosen solution method is presented.

  15. Watershed-based Image Segmentation with Region Merging and Edge Detection

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The clustering technique is used to examine each pixel in the image which assigned to one of the clusters depending on the minimum distance to obtain primary classified image into different intensity regions. A watershed transformation technique is then employes. This includes: gradient of the classified image, dividing the image into markers, checking the Marker Image to see if it has zero points (watershed lines). The watershed lines are then deleted in the Marker Image created by watershed algorithm. A Region Adjacency Graph (RAG) and Region Adjacency Boundary (RAB) are created between two regions from Marker Image. Finally region merging is done according to region average intensity and two edge strengths (T1, T2). The approach of the authors is tested on remote sensing and brain MR medical images. The final segmentation result is one closed boundary per actual region in the image.

  16. Optical scatterometry system for detecting specific line edge roughness of resist gratings subjected to detector noises

    International Nuclear Information System (INIS)

    Lee, Yen-Min; Li, Jia-Han; Cheng, Hsin-Hung; Wang, Fu-Min; Shen, Yu-Tian; Tsai, Kuen-Yu; Shieh, Jason J; Chen, Alek C

    2014-01-01

    The Fourier scatterometry model was used to measure the ZEP 520A electron beam resist lines with specific line edge roughness (LER). By obtaining the pupils via an objective lens, the angle-resolved diffraction spectrum was collected efficiently without additional mechanical scanning. The concavity of the pupil was considered as the weight function in specimen recognition. A series of white noises was examined in the model, and the tolerant white noise levels for different system numerical apertures (NAs) were reported. Our numerical results show that the scatterometry model of a higher NA can identify a target with a higher white noise level. Moreover, the fabricated ZEP 520A electron beam resist gratings with LER were measured by using our model, and the fitting results were matched with scanning electron microscope measurements. (paper)

  17. Development programs of cutting-edge technologies for measurement and detection of nuclear material for safeguards and security

    International Nuclear Information System (INIS)

    Seya, Michio; Wakabayashi, Shuji; Naoi, Yosuke; Ohkubo, Michiaki; Senzaki, Masao

    2011-01-01

    The Integrated Support Center for Nuclear Nonproliferation and Nuclear Security ('ISCN', hereafter) of Japan Atomic Energy Agency (JAEA) has development programs of cutting-edge technologies for measurement and detection of nuclear materials for nuclear safeguards and security, under the sponsorship of Japanese government (MEXT: Ministry of Education, Culture, Sports, Science and Technology). ISCN started development programs of the following technologies this year. (1) NRF (Nuclear Resonance Fluorescence) NDA technology using laser Compton scattering (LCS) gamma-rays, (2) Alternative to 3 He neutron detection technology using inorganic solid scintillator. ISCN is also going to conduct a demonstration test of a spent fuel Pu-NDA system that is to be developed by LANL (Los Alamos National Laboratory) using very sophisticated neutron measurement technologies, under JAEA/USDOE cooperation agreement. This presentation shows the above programs of ISCN. (author)

  18. Using spectral-domain optical coherence tomography to detect optic neuropathy in patients with craniosynostosis.

    Science.gov (United States)

    Dagi, Linda R; Tiedemann, Laura M; Heidary, Gena; Robson, Caroline D; Hall, Amber M; Zurakowski, David

    2014-12-01

    Detecting and monitoring optic neuropathy in patients with craniosynostosis is a clinical challenge due to limited cooperation, and subjective measures of visual function. The purpose of this study was to appraise the correlation of peripapillary retinal nerve fiber layer (RNFL) thickness measured by spectral-domain ocular coherence tomography (SD-OCT) with indication of optic neuropathy based on fundus examination. The medical records of all patients with craniosynostosis presenting for ophthalmic evaluation during 2013 were retrospectively reviewed. The following data were abstracted from the record: diagnosis, historical evidence of elevated intracranial pressure, current ophthalmic evaluation and visual field results, and current peripapillary RNFL thickness. A total of 54 patients were included (mean age, 10.6 years [range, 2.4-33.8 years]). Thirteen (24%) had evidence of optic neuropathy based on current fundus examination. Of these, 10 (77%) demonstrated either peripapillary RNFL elevation and papilledema or depression with optic atrophy. Sensitivity for detecting optic atrophy was 88%; for papilledema, 60%; and for either form of optic neuropathy, 77%. Specificity was 94%, 90%, and 83%, respectively. Kappa agreement was substantial for optic atrophy (κ = 0.73) and moderate for papilledema (κ = 0.39) and for either form of optic neuropathy (κ = 0.54). Logistic regression indicated that peripapillary RNFL thickness was predictive of optic neuropathy (P optic neuropathy than visual field testing (likelihood ratio = 10.02; P = 0.002). Sensitivity and specificity of logMAR visual acuity in detecting optic neuropathy were 15% and 95%, respectively. Peripapillary RNFL thickness measured by SD-OCT provides adjunctive evidence for identifying optic neuropathy in patients with craniosynostosis and appears more sensitive at detecting optic atrophy than papilledema. Copyright © 2014 American Association for Pediatric Ophthalmology and Strabismus. Published by

  19. Fundus auto fluorescence and spectral domain ocular coherence tomography in the early detection of chloroquine retinopathy

    Directory of Open Access Journals (Sweden)

    Megan B. Goodman

    2015-08-01

    Full Text Available Purpose: To determine the sensitivity of spectral domain ocular coherence tomography (SD-OCT and fundus auto fluorescence (FAF images as a screening test to detect early changes in the retina prior to the onset of chloroquine retinopathy. Method: The study was conducted using patients taking chloroquine (CQ, referred by the Rheumatology Department to the Ophthalmology Department at Tygerberg Academic Hospital. Group A consisted of 59 patients on CQ for less than 5 years, and Group B consisted of 53 patients on CQ for more than 5 years. A 200 × 200 macula thickness map, 5-line raster SD-OCT on a Carl Zeiss Meditec Cirrus HD-OCT and FAF images on a Carl Zeiss Meditec Visucam 500 were recorded for 223 eyes. Images were reviewed independently, and then those of Groups A and B compared. Results: There were no statistically significant differences between Groups A and B. The criteria included the internal limiting membrane and the retinal pigment epithelium (ILM-RPE thickness, interdigitation zone integrity (p = 0.891, df = 1, χ² = 0.1876, ellipsoid zone integrity (p = 0.095, df = 2, χ² = 4.699 and FAF image irregularities (p = 0.479, df = 1, χ²= 4995978. Conclusion: The inclusion of SD-OCT and FAF as objective tests into the prescribed screening guidelines does not appear to simplify the detection of subclinical injury in patients on chloroquine treatment.

  20. New Approach for Snow Cover Detection through Spectral Pattern Recognition with MODIS Data

    Directory of Open Access Journals (Sweden)

    Kyeong-Sang Lee

    2017-01-01

    Full Text Available Snow cover plays an important role in climate and hydrology, at both global and regional scales. Most previous studies have used static threshold techniques to detect snow cover, which can lead to errors such as misclassification of snow and clouds, because the reflectance of snow cover exhibits variability and is affected by several factors. Therefore, we present a simple new algorithm for mapping snow cover from Moderate Resolution Imaging Spectroradiometer (MODIS data using dynamic wavelength warping (DWW, which is based on dynamic time warping (DTW. DTW is a pattern recognition technique that is widely used in various fields such as human action recognition, anomaly detection, and clustering. Before performing DWW, we constructed 49 snow reflectance spectral libraries as reference data for various solar zenith angle and digital elevation model conditions using approximately 1.6 million sampled data. To verify the algorithm, we compared our results with the MODIS swath snow cover product (MOD10_L2. Producer’s accuracy, user’s accuracy, and overall accuracy values were 92.92%, 78.41%, and 92.24%, respectively, indicating good overall classification accuracy. The proposed algorithm is more useful for discriminating between snow cover and clouds than threshold techniques in some areas, such as those with a high viewing zenith angle.

  1. NIR detection of honey adulteration reveals differences in water spectral pattern.

    Science.gov (United States)

    Bázár, György; Romvári, Róbert; Szabó, András; Somogyi, Tamás; Éles, Viktória; Tsenkova, Roumiana

    2016-03-01

    High fructose corn syrup (HFCS) was mixed with four artisanal Robinia honeys at various ratios (0-40%) and near infrared (NIR) spectra were recorded with a fiber optic immersion probe. Levels of HFCS adulteration could be detected accurately using leave-one-honey-out cross-validation (RMSECV=1.48; R(2)CV=0.987), partial least squares regression and the 1300-1800nm spectral interval containing absorption bands related to both water and carbohydrates. Aquaphotomics-based evaluations showed that unifloral honeys contained more highly organized water than the industrial sugar syrup, supposedly because of the greater variety of molecules dissolved in the multi-component honeys. Adulteration with HFCS caused a gradual reduction of water molecular structures, especially water trimers, which facilitate interaction with other molecules. Quick, non-destructive NIR spectroscopy combined with aquaphotomics could be used to describe water molecular structures in honey and to detect a rather common form of adulteration. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Semi-supervised spectral algorithms for community detection in complex networks based on equivalence of clustering methods

    Science.gov (United States)

    Ma, Xiaoke; Wang, Bingbo; Yu, Liang

    2018-01-01

    Community detection is fundamental for revealing the structure-functionality relationship in complex networks, which involves two issues-the quantitative function for community as well as algorithms to discover communities. Despite significant research on either of them, few attempt has been made to establish the connection between the two issues. To attack this problem, a generalized quantification function is proposed for community in weighted networks, which provides a framework that unifies several well-known measures. Then, we prove that the trace optimization of the proposed measure is equivalent with the objective functions of algorithms such as nonnegative matrix factorization, kernel K-means as well as spectral clustering. It serves as the theoretical foundation for designing algorithms for community detection. On the second issue, a semi-supervised spectral clustering algorithm is developed by exploring the equivalence relation via combining the nonnegative matrix factorization and spectral clustering. Different from the traditional semi-supervised algorithms, the partial supervision is integrated into the objective of the spectral algorithm. Finally, through extensive experiments on both artificial and real world networks, we demonstrate that the proposed method improves the accuracy of the traditional spectral algorithms in community detection.

  3. Identification of pulpitis at dental X-ray periapical radiography based on edge detection, texture description and artificial neural networks

    Directory of Open Access Journals (Sweden)

    Bernard Y Tumbelaka

    2014-01-01

    Full Text Available Objectives: The aim of the present research was to identify pulpitis through periapical radiography by applying edges as basis image features, the texture description and the artificial neural networks (ANNs. Materials and Methods: Input image data records of 10 molar and 10 canine teeth were used. The clinical diagnosis of interest cases were represented as normal pulp, reversible and irreversible pulpitis, and necrotic pulp. The following image processing steps were done. First, the data records were converted digitally and preprocessed as its original image using the Gaussian Filter to obtain the best smoothed intensity distribution. Second, the local image differentiation was used to produce edge detector operators, e(x,y as the image gradient; ∇f(x,y providing useful information about the local intensity variations. Third, these results were analyzed by using the texture descriptors to obtain digitally the image entropy, H. The fourth step, all were characterized by the ANNs. Results: The edge detection carried important information about the object boundaries of pulpal health and pain conditions in the dental pulp significantly. The image entropy which was identified, the diagnostic term, was obtained from texture descriptors in the segmentation regions where the curves of pulp states tent convergence with the normal pulp line from 4.9014 to 4.6843 decreasing to the reversible and the irreversible pulpitis line include the nectrotic pulp line from 4.6812 to 4.5926 and then inputting to the ANNs analysis at the same of mean square error around 0.0003. Conclusions: Referred to these results, the correlation of the image entropy and the ANNs analysis could be linearly classified with the critical point of 4.6827. Finally, it could be concluded that the direct reading radiography is better to be digitized in order to provide us the best choice for diagnosis validation.

  4. Acoustic Event Detection in Multichannel Audio Using Gated Recurrent Neural Networks with High‐Resolution Spectral Features

    Directory of Open Access Journals (Sweden)

    Hyoung‐Gook Kim

    2017-12-01

    Full Text Available Recently, deep recurrent neural networks have achieved great success in various machine learning tasks, and have also been applied for sound event detection. The detection of temporally overlapping sound events in realistic environments is much more challenging than in monophonic detection problems. In this paper, we present an approach to improve the accuracy of polyphonic sound event detection in multichannel audio based on gated recurrent neural networks in combination with auditory spectral features. In the proposed method, human hearing perception‐based spatial and spectral‐domain noise‐reduced harmonic features are extracted from multichannel audio and used as high‐resolution spectral inputs to train gated recurrent neural networks. This provides a fast and stable convergence rate compared to long short‐term memory recurrent neural networks. Our evaluation reveals that the proposed method outperforms the conventional approaches.

  5. Testing of the method for water microleakage detection from OH hydroxyl spectral lines at the L-2M stellarator

    International Nuclear Information System (INIS)

    Voronov, G. S.; Berezhetskii, M. S.; Bondar’, Yu. F.; Vafin, I. Yu.; Vasil’kov, D. G.; Voronova, E. V.; Grebenshchikov, S. E.; Grishina, I. A.; Larionova, N. F.; Letunov, A. A.; Logvinenko, V. P.; Meshcheryakov, A. I.; Pleshkov, E. I.; Khol’nov, Yu. V.; Fedyanin, O. I.; Tsygankov, V. A.; Shchepetov, S. V.; Kurnaev, V. A.; Vizgalov, I. V.; Urusov, V. A.

    2013-01-01

    Results are presented from L-2M stellarator experiments on testing a possible method for detection of water microleakages in the cooling system of the first wall and vacuum chamber of ITER. The method consists in the spectroscopic detection of spectral lines of the OH hydroxyl, which forms via the dissociation of water molecules in plasma. Emission in the spectral band of 305–310 nm can be detected even at water leakage rates less than 10 −4 Pa m 3 /s. Chemical reactions between water and boron compounds on the vacuum chamber wall delay the detection of leakages up to ∼2000 s. A similar phenomenon can be expected when a leakage will occur in ITER, where the materials suggested for the first wall (Be, Li) can also chemically react with water.

  6. Spectral Detection of Human Skin in VIS-SWIR Hyperspectral Imagery without Radiometric Calibration

    Science.gov (United States)

    2012-03-01

    6 Spectral reflectance of human skin at VIS-SWIR wavelengths. Skin with less melanin appears brighter because it has higher reflectance...6 illustrates the spectral reflectance of human skin with different melanin levels. One paper proposes a Normalized Difference Skin Index (NDSI), a...1.4% Melanin 12.6% Melanin 23.2% Melanin 34.3% Melanin 45% Melanin Figure 6. Spectral reflectance of human skin at VIS-SWIR wavelengths. Skin with less

  7. Using hyper-spectral indices to detect soil phosphorus concentration for various land use patterns.

    Science.gov (United States)

    Lin, Chen; Ma, Ronghua; Zhu, Qing; Li, Jingtao

    2015-01-01

    The management of nonpoint source pollution requires accurate information regarding soil phosphorus concentrations for different land use patterns. The use of remotely sensed information provides an important opportunity for such studies, and the previous studies showed that soil phosphorus shows no clear spectral response feature, while the phosphorus concentrations can be indirectly detected from the normalised difference vegetation indices (NDVI). Therefore, this study uses an optimised index in the RED and near-infrared (NIR) wavelengths to estimate total phosphorus and Olsen-P concentrations. The prediction accuracy is not entirely satisfactory with respect to a mixed land use dataset in which the determination coefficient was maintained at approximately 0.6, with particularly poor performance obtained for forest land group. However, the prediction accuracy increases markedly with the separation of samples into broad land use categories, even the R(2) was exceeded 0.8 for tea plantation group. The soil phosphorus prediction effect showed obvious variance for different land use patterns, which was related to vegetation growth conditions and critical soil properties including soil organic matter and mechanical composition.

  8. X-ray spectral determination by detection of radiation scattered at different angles

    International Nuclear Information System (INIS)

    Barrea, Raul; Mainardi, R.T.

    1987-01-01

    A precise knowledge of the spectral content of an X-ray beam is of fundamental importance in areas such as X-ray fluorescence analysis by absolute methods, radiodiagnosis, radiotherapy, computed tomography, etc. A simple practical method was developed to determine X-ray spectra emitted by X-ray tubes. It is based on the scattering of the beam on a solid target and detection of this radiation at different angles. This methodology can easily be adapted to the successive attenuation of the beam procedure. Numerical parameter values of a proposed analytical function for the energy spectrum are found measuring the radiation intensity with a suitable detector (ionization chamber or plastic scintillation detector) and equating it with the convolution integral of the proposed spectrum with the incoherent scattering function. This procedure of spectra determination is enclosed in the same group of those generically referred as successive modifications of the irradiation set up used in absolute methods of X-ray fluorescence analysis. (Author) [es

  9. Nonlinear Bayesian Algorithms for Gas Plume Detection and Estimation from Hyper-spectral Thermal Image Data

    Energy Technology Data Exchange (ETDEWEB)

    Heasler, Patrick G.; Posse, Christian; Hylden, Jeff L.; Anderson, Kevin K.

    2007-06-13

    This paper presents a nonlinear Bayesian regression algorithm for the purpose of detecting and estimating gas plume content from hyper-spectral data. Remote sensing data, by its very nature, is collected under less controlled conditions than laboratory data. As a result, the physics-based model that is used to describe the relationship between the observed remotesensing spectra, and the terrestrial (or atmospheric) parameters that we desire to estimate, is typically littered with many unknown "nuisance" parameters (parameters that we are not interested in estimating, but also appear in the model). Bayesian methods are well-suited for this context as they automatically incorporate the uncertainties associated with all nuisance parameters into the error estimates of the parameters of interest. The nonlinear Bayesian regression methodology is illustrated on realistic simulated data from a three-layer model for longwave infrared (LWIR) measurements from a passive instrument. This shows that this approach should permit more accurate estimation as well as a more reasonable description of estimate uncertainty.

  10. EUSO-BALLOON a pathfinder for detecting UHECR's from the edge of space

    Directory of Open Access Journals (Sweden)

    Scotti V.

    2013-06-01

    Full Text Available EUSO-Balloon has been conceived as a pathfinder mission for JEM-EUSO, to perform an end-to-end test of the subsystems and components, and to prove the global detection chain while improving our knowledge of the atmospheric and terrestrial UV background. Through a series of stratospheric balloon flights performed by the French Space Agency CNES, EUSO-BALLOON will serve as an evolutive test-bench for all the key technologies of JEM-EUSO. EUSO-Balloon also has the potential to detect Extensive Air Showers from above, marking a key milestone in the development of UHECR science, and paving the way for any future large scale, space-based UHECR observatory.

  11. SU-D-BRA-04: Fractal Dimension Analysis of Edge-Detected Rectal Cancer CTs for Outcome Prediction

    International Nuclear Information System (INIS)

    Zhong, H; Wang, J; Hu, W; Shen, L; Wan, J; Zhou, Z; Zhang, Z

    2015-01-01

    Purpose: To extract the fractal dimension features from edge-detected rectal cancer CTs, and to examine the predictability of fractal dimensions to outcomes of primary rectal cancer patients. Methods: Ninety-seven rectal cancer patients treated with neo-adjuvant chemoradiation were enrolled in this study. CT images were obtained before chemoradiotherapy. The primary lesions of the rectal cancer were delineated by experienced radiation oncologists. These images were extracted and filtered by six different Laplacian of Gaussian (LoG) filters with different filter values (0.5–3.0: from fine to coarse) to achieve primary lesions in different anatomical scales. Edges of the original images were found at zero-crossings of the filtered images. Three different fractal dimensions (box-counting dimension, Minkowski dimension, mass dimension) were calculated upon the image slice with the largest cross-section of the primary lesion. The significance of these fractal dimensions in survival, recurrence and metastasis were examined by Student’s t-test. Results: For a follow-up time of two years, 18 of 97 patients had experienced recurrence, 24 had metastasis, and 18 were dead. Minkowski dimensions under large filter values (2.0, 2.5, 3.0) were significantly larger (p=0.014, 0.006, 0.015) in patients with recurrence than those without. For metastasis, only box-counting dimensions under a single filter value (2.5) showed differences (p=0.016) between patients with and without. For overall survival, box-counting dimensions (filter values = 0.5, 1.0, 1.5), Minkowski dimensions (filter values = 0.5, 1.5, 2.0, 2,5) and mass dimensions (filter values = 1.5, 2.0) were all significant (p<0.05). Conclusion: It is feasible to extract shape information by edge detection and fractal dimensions analysis in neo-adjuvant rectal cancer patients. This information can be used to prognosis prediction

  12. A powerful nonparametric method for detecting differentially co-expressed genes: distance correlation screening and edge-count test.

    Science.gov (United States)

    Zhang, Qingyang

    2018-05-16

    Differential co-expression analysis, as a complement of differential expression analysis, offers significant insights into the changes in molecular mechanism of different phenotypes. A prevailing approach to detecting differentially co-expressed genes is to compare Pearson's correlation coefficients in two phenotypes. However, due to the limitations of Pearson's correlation measure, this approach lacks the power to detect nonlinear changes in gene co-expression which is common in gene regulatory networks. In this work, a new nonparametric procedure is proposed to search differentially co-expressed gene pairs in different phenotypes from large-scale data. Our computational pipeline consisted of two main steps, a screening step and a testing step. The screening step is to reduce the search space by filtering out all the independent gene pairs using distance correlation measure. In the testing step, we compare the gene co-expression patterns in different phenotypes by a recently developed edge-count test. Both steps are distribution-free and targeting nonlinear relations. We illustrate the promise of the new approach by analyzing the Cancer Genome Atlas data and the METABRIC data for breast cancer subtypes. Compared with some existing methods, the new method is more powerful in detecting nonlinear type of differential co-expressions. The distance correlation screening can greatly improve computational efficiency, facilitating its application to large data sets.

  13. Calculation of near-edge x-ray-absorption fine structure at finite temperatures: Spectral signatures of hydrogen bond breaking in liquid water

    International Nuclear Information System (INIS)

    Hetenyi, Balazs; De Angelis, Filippo; Giannozzi, Paolo; Car, Roberto

    2004-01-01

    We calculate the near-edge x-ray-absorption fine structure of H 2 O in the gas, hexagonal ice, and liquid phases using heuristic density-functional based methods. We present a detailed comparison of our results with experiment. The differences between the ice and water spectra can be rationalized in terms of the breaking of hydrogen bonds around the absorbing molecule. In particular the increase in the pre-edge absorption feature from ice to water is shown to be due to the breaking of a donor hydrogen bond. We also find that in water approximately 19% of hydrogen bonds are broken

  14. Feasibility of spectral shaping for detection and quantification of coronary calcifications in ultra-low dose CT

    Energy Technology Data Exchange (ETDEWEB)

    Vonder, Marleen; Pelgrim, Gert Jan; Vliegenthart, Rozemarijn [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen (Netherlands); Huijsse, Sevrin E.M.; Greuter, Marcel J.W. [University of Groningen, University Medical Center Groningen, Department of Radiology, Groningen (Netherlands); Meyer, Mathias; Henzler, Thomas [Heidelberg University, Institute of Clinical Radiology and Nuclear Medicine, Medical Faculty Mannheim, University Medical Center Mannheim, Heidelberg (Germany); Flohr, Thomas G. [Siemens Healthcare GmbH, Computed Tomography, Forchheim (Germany); Oudkerk, Matthijs [University of Groningen, University Medical Center Groningen, Center for Medical Imaging North-East Netherlands (CMI-NEN), Groningen (Netherlands)

    2017-05-15

    To evaluate detectability and quantification of coronary calcifications for CT with a tin filter for spectral shaping. Phantom inserts with 100 small and 9 large calcifications, and a moving artificial artery with 3 calcifications (speed 0-30 mm/s) were placed in a thorax phantom simulating different patient sizes. The phantom was scanned in high-pitch spiral mode at 100 kVp with tin filter (Sn100 kVp), and at a reference of 120 kVp, with electrocardiographic (ECG) gating. Detectability and quantification of calcifications were analyzed for standard (130 HU) and adapted thresholds. Sn100 kVp yielded lower detectability of calcifications (9 % versus 12 %, p = 0.027) and lower Agatston scores (p < 0.008), irrespective of calcification, patient size and speed. Volume scores of the moving calcifications for Sn100 kVp at speed 10-30 mm/s were lower (p < 0.001), while mass scores were similar (p = 0.131). For Sn100 kVp with adapted threshold of 117 HU, detectability (p = 1.000) and Agatston score (p > 0.206) were similar to 120 kVp. Spectral shaping resulted in median dose reduction of 62.3 % (range 59.0-73.4 %). Coronary calcium scanning with spectral shaping yields lower detectability of calcifications and lower Agatston scores compared to 120 kVp scanning, for which a HU threshold correction should be developed. (orig.)

  15. Identification of breast edges and detection of microcalcifications with orthogonal polynomials model

    International Nuclear Information System (INIS)

    Krishnamoorthy, R.; Amudhavalli, N.; Sivakolundu, M.K.

    2008-01-01

    Medical image processing involves analysis of radiographic images in a quantitative way using technologies related to computer vision, artificial intelligence etc. In recent years, it has been recognized that breast cancer is one of the major causes of mortality increase to mid-aged women, especially in developed countries and mammography is accepted as the most effective method for early detection of breast cancer. It is also reported that interpretation of x-ray mammograms is difficult due to small differences in image density of various breast tissues, especially dense breasts. The two main indicators of breast cancer in a mammogram are the presence of a tumor mass and the presence of clustered microcalcifications

  16. A Narrative Approach to Detect the Vehicles using color, texture and edge based techniques

    Directory of Open Access Journals (Sweden)

    Gaurav Ravi

    2016-01-01

    Full Text Available Vehicle recognition is the chief stride in observing the speeding vehicles in a thruway. The feature arrangements caught by a stationary camera demonstrate to us that there’s a requirement for a vehicle location calculation which handles sudden light change furthermore the situations where the closer view converges away from plain sight. This paper gives us a study of different foundation subtraction systems that are utilized for recognizing the vehicles effectively. Vehicles proceeding onward street are of significance on the grounds that issues like movement blockage, monetary waste, sticking on the underpasses and over-extensions (if the vehicle going through is not of the passable size are connected with them. Index Terms—Vehicle Detection, video sequences, foreground, background, MATLAB, RGB conversion.

  17. A joint estimation detection of Glaucoma progression in 3D spectral domain optical coherence tomography optic nerve head images

    Science.gov (United States)

    Belghith, Akram; Bowd, Christopher; Weinreb, Robert N.; Zangwill, Linda M.

    2014-03-01

    Glaucoma is an ocular disease characterized by distinctive changes in the optic nerve head (ONH) and visual field. Glaucoma can strike without symptoms and causes blindness if it remains without treatment. Therefore, early disease detection is important so that treatment can be initiated and blindness prevented. In this context, important advances in technology for non-invasive imaging of the eye have been made providing quantitative tools to measure structural changes in ONH topography, an essential element for glaucoma detection and monitoring. 3D spectral domain optical coherence tomography (SD-OCT), an optical imaging technique, has been commonly used to discriminate glaucomatous from healthy subjects. In this paper, we present a new framework for detection of glaucoma progression using 3D SD-OCT images. In contrast to previous works that the retinal nerve fiber layer (RNFL) thickness measurement provided by commercially available spectral-domain optical coherence tomograph, we consider the whole 3D volume for change detection. To integrate a priori knowledge and in particular the spatial voxel dependency in the change detection map, we propose the use of the Markov Random Field to handle a such dependency. To accommodate the presence of false positive detection, the estimated change detection map is then used to classify a 3D SDOCT image into the "non-progressing" and "progressing" glaucoma classes, based on a fuzzy logic classifier. We compared the diagnostic performance of the proposed framework to existing methods of progression detection.

  18. Bearing failure detection of micro wind turbine via power spectral density analysis for stator current signals spectrum

    Science.gov (United States)

    Mahmood, Faleh H.; Kadhim, Hussein T.; Resen, Ali K.; Shaban, Auday H.

    2018-05-01

    The failure such as air gap weirdness, rubbing, and scrapping between stator and rotor generator arise unavoidably and may cause extremely terrible results for a wind turbine. Therefore, we should pay more attention to detect and identify its cause-bearing failure in wind turbine to improve the operational reliability. The current paper tends to use of power spectral density analysis method of detecting internal race and external race bearing failure in micro wind turbine by estimation stator current signal of the generator. The failure detector method shows that it is well suited and effective for bearing failure detection.

  19. Detecting Interplanetary Dust Particles with Radars to Study the Dynamics at the Edge of the Space

    Science.gov (United States)

    Janches, Diego

    2015-01-01

    The Earth's mesosphere is the region of the atmosphere between approximately 60-120 km altitude, where the transition from hydrodynamic flow to molecular diffusion occurs. It is highly dynamic region where turbulence by wave braking is produced and energy is deposited from sources from both, below and above this altitude range. Because aircraft and nearly all balloons reach altitudes below approximately 50 km and orbital spacecrafts are well above approximately 400 km, the mesosphere has only been accessed through the use of sounding rockets or remote sensing techniques, and as a result, it is the most poorly understood part of the atmosphere. In addition, millions of Interplanetary Dust Particles (IDPs) enter the atmosphere. Within the mesosphere most of these IDPs melt or vaporize as a result of collisions with the air particles producing meteors that can be detected with radars. This provides a mean to study the dynamics of this region. In this lecture the basic principles of the utilization of meteor radars to study the dynamics of the mesosphere will be presented. A system overview of these systems will be provided as well as discuss the advantages/disadvantages of these systems, provide details of the data processing methodology and give a brief overview of the current status of the field as well as the vision for the next decade.

  20. [Influence of Spectral Pre-Processing on PLS Quantitative Model of Detecting Cu in Navel Orange by LIBS].

    Science.gov (United States)

    Li, Wen-bing; Yao, Lin-tao; Liu, Mu-hua; Huang, Lin; Yao, Ming-yin; Chen, Tian-bing; He, Xiu-wen; Yang, Ping; Hu, Hui-qin; Nie, Jiang-hui

    2015-05-01

    Cu in navel orange was detected rapidly by laser-induced breakdown spectroscopy (LIBS) combined with partial least squares (PLS) for quantitative analysis, then the effect on the detection accuracy of the model with different spectral data ptetreatment methods was explored. Spectral data for the 52 Gannan navel orange samples were pretreated by different data smoothing, mean centralized and standard normal variable transform. Then 319~338 nm wavelength section containing characteristic spectral lines of Cu was selected to build PLS models, the main evaluation indexes of models such as regression coefficient (r), root mean square error of cross validation (RMSECV) and the root mean square error of prediction (RMSEP) were compared and analyzed. Three indicators of PLS model after 13 points smoothing and processing of the mean center were found reaching 0. 992 8, 3. 43 and 3. 4 respectively, the average relative error of prediction model is only 5. 55%, and in one word, the quality of calibration and prediction of this model are the best results. The results show that selecting the appropriate data pre-processing method, the prediction accuracy of PLS quantitative model of fruits and vegetables detected by LIBS can be improved effectively, providing a new method for fast and accurate detection of fruits and vegetables by LIBS.

  1. Application of spectral decomposition of LIDAR-based headwind profiles in windshear detection at the Hong Kong International Airport

    Directory of Open Access Journals (Sweden)

    Tsz-Chun Wu

    2018-01-01

    Full Text Available In aviation, rapidly fluctuating headwind/tailwind may lead to high horizontal windshear, posing potential safety hazards to aircraft. So far, windshear alerts are issued by considering directly the headwind differences measured along the aircraft flight path (e.g. based on Doppler velocities from remote-sensing. In this paper, we propose and demonstrate a new methodology for windshear alerting with the technique of spectral decomposition. Through Fourier transformation of the LIDAR-based headwind profiles in 2012 and 2014 at arrival corridors 07LA and 25RA of the Hong Kong International Airport (HKIA, we study the occurrence of windshear in the spectral domain. Using a threshold-based approach, we investigate performance of single and multiple channel detection algorithms and validate the results against pilot reports. With the receiver operating characteristic (ROC diagram, we successfully demonstrate feasibility of this approach to alert windshear by showing a comparable performance of the triple channel detection algorithm and a consistent hit rate gain (07LA in particular of 4.5 to 8 % in quadruple channel detection against GLYGA, which is the currently operational algorithm in HKIA. We also observe that some length scales are particularly sensitive to windshear events which may be closely related to the local geography of HKIA. This study serves to open a new door for the methodology of windshear detection in the spectral domain for the aviation community.

  2. A rotated transmission grating spectrometer for detecting spectral separation of doublet Na

    Energy Technology Data Exchange (ETDEWEB)

    Santosa, Ignatius Edi [Department of Physics Education, Sanata Dharma University, Paingan Maguwohardjo Depok Sleman, Yogyakarta 55281, Indonesia edi@usd.ac.id (Indonesia)

    2015-04-16

    Transmission gratings are usually used in a spectrometer for measuring the wavelength of light. In the common design, the position of the grating is perpendicular to the incident light. In order to increase the angular dispersion, in contrary to the common design, in this experiment the transmission grating was rotated. Due to the non-zero incident angle, the diffracted light was shifted. This rotated transmission grating spectrometer has been used to determine the separation of doublet Na. In this experiment, the diffraction angle was measured at various incident angles. The spectral separation of doublet Na was identified from the difference in the diffraction angle of two spectral lines. This spectral separation depends on the incident angle, the grating constant and the order of diffraction. As the effect of increasing the incident angle, a significant increase of the spectral separation can be achieved up to three fold.

  3. A rotated transmission grating spectrometer for detecting spectral separation of doublet Na

    International Nuclear Information System (INIS)

    Santosa, Ignatius Edi

    2015-01-01

    Transmission gratings are usually used in a spectrometer for measuring the wavelength of light. In the common design, the position of the grating is perpendicular to the incident light. In order to increase the angular dispersion, in contrary to the common design, in this experiment the transmission grating was rotated. Due to the non-zero incident angle, the diffracted light was shifted. This rotated transmission grating spectrometer has been used to determine the separation of doublet Na. In this experiment, the diffraction angle was measured at various incident angles. The spectral separation of doublet Na was identified from the difference in the diffraction angle of two spectral lines. This spectral separation depends on the incident angle, the grating constant and the order of diffraction. As the effect of increasing the incident angle, a significant increase of the spectral separation can be achieved up to three fold

  4. Importance of spatial and spectral data reduction in the detection of internal defects in food products.

    Science.gov (United States)

    Zhang, Xuechen; Nansen, Christian; Aryamanesh, Nader; Yan, Guijun; Boussaid, Farid

    2015-04-01

    Despite the importance of data reduction as part of the processing of reflection-based classifications, this study represents one of the first in which the effects of both spatial and spectral data reductions on classification accuracies are quantified. Furthermore, the effects of approaches to data reduction were quantified for two separate classification methods, linear discriminant analysis (LDA) and support vector machine (SVM). As the model dataset, reflection data were acquired using a hyperspectral camera in 230 spectral channels from 401 to 879 nm (spectral resolution of 2.1 nm) from field pea (Pisum sativum) samples with and without internal pea weevil (Bruchus pisorum) infestation. We deployed five levels of spatial data reduction (binning) and eight levels of spectral data reduction (40 datasets). Forward stepwise LDA was used to select and include only spectral channels contributing the most to the separation of pixels from non-infested and infested field peas. Classification accuracies obtained with LDA and SVM were based on the classification of independent validation datasets. Overall, SVMs had significantly higher classification accuracies than LDAs (P food products with internal defects, and it highlights that spatial and spectral data reductions can (1) improve classification accuracies, (2) vastly decrease computer constraints, and (3) reduce analytical concerns associated with classifications of large and high-dimensional datasets.

  5. Technical Note: Range verification system using edge detection method for a scintillator and a CCD camera system

    Energy Technology Data Exchange (ETDEWEB)

    Saotome, Naoya, E-mail: naosao@nirs.go.jp; Furukawa, Takuji; Hara, Yousuke; Mizushima, Kota; Tansho, Ryohei; Saraya, Yuichi; Shirai, Toshiyuki; Noda, Koji [Department of Research Center for Charged Particle Therapy, National Institute of Radiological Sciences, 4-9-1 Anagawa, Inage-ku, Chiba 263-8555 (Japan)

    2016-04-15

    Purpose: Three-dimensional irradiation with a scanned carbon-ion beam has been performed from 2011 at the authors’ facility. The authors have developed the rotating-gantry equipped with the scanning irradiation system. The number of combinations of beam properties to measure for the commissioning is more than 7200, i.e., 201 energy steps, 3 intensities, and 12 gantry angles. To compress the commissioning time, quick and simple range verification system is required. In this work, the authors develop a quick range verification system using scintillator and charge-coupled device (CCD) camera and estimate the accuracy of the range verification. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The optical spatial resolution of the system is 0.2 mm/pixel. The camera control system was connected and communicates with the measurement system that is part of the scanning system. The range was determined by image processing. Reference range for each energy beam was determined by a difference of Gaussian (DOG) method and the 80% of distal dose of the depth-dose distribution that were measured by a large parallel-plate ionization chamber. The authors compared a threshold method and a DOG method. Results: The authors found that the edge detection method (i.e., the DOG method) is best for the range detection. The accuracy of range detection using this system is within 0.2 mm, and the reproducibility of the same energy measurement is within 0.1 mm without setup error. Conclusions: The results of this study demonstrate that the authors’ range check system is capable of quick and easy range verification with sufficient accuracy.

  6. Technical Note: Range verification system using edge detection method for a scintillator and a CCD camera system

    International Nuclear Information System (INIS)

    Saotome, Naoya; Furukawa, Takuji; Hara, Yousuke; Mizushima, Kota; Tansho, Ryohei; Saraya, Yuichi; Shirai, Toshiyuki; Noda, Koji

    2016-01-01

    Purpose: Three-dimensional irradiation with a scanned carbon-ion beam has been performed from 2011 at the authors’ facility. The authors have developed the rotating-gantry equipped with the scanning irradiation system. The number of combinations of beam properties to measure for the commissioning is more than 7200, i.e., 201 energy steps, 3 intensities, and 12 gantry angles. To compress the commissioning time, quick and simple range verification system is required. In this work, the authors develop a quick range verification system using scintillator and charge-coupled device (CCD) camera and estimate the accuracy of the range verification. Methods: A cylindrical plastic scintillator block and a CCD camera were installed on the black box. The optical spatial resolution of the system is 0.2 mm/pixel. The camera control system was connected and communicates with the measurement system that is part of the scanning system. The range was determined by image processing. Reference range for each energy beam was determined by a difference of Gaussian (DOG) method and the 80% of distal dose of the depth-dose distribution that were measured by a large parallel-plate ionization chamber. The authors compared a threshold method and a DOG method. Results: The authors found that the edge detection method (i.e., the DOG method) is best for the range detection. The accuracy of range detection using this system is within 0.2 mm, and the reproducibility of the same energy measurement is within 0.1 mm without setup error. Conclusions: The results of this study demonstrate that the authors’ range check system is capable of quick and easy range verification with sufficient accuracy.

  7. Analysis of sea-surface radar signatures by means of wavelet-based edge detection and detection of regularities; Analyse von Radarsignaturen der Meeresoberflaeche mittels auf Wavelets basierender Kantenerkennung und Regularitaetsbestimmung

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, U. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Gewaesserphysik

    2000-07-01

    The derivation and implementation of an algorithm for edge detection in images and for the detection of the Lipschitz regularity in edge points are described. The method is based on the use of the wavelet transform for edge detection at different resolutions. The Lipschitz regularity is a measure that characterizes the edges. The description of the derivation is first performed in one dimension. The approach of Mallat is formulated consistently and proved. Subsequently, the two-dimensional case is addressed, for which the derivation, as well as the description of the algorithm, is analogous. The algorithm is applied to detect edges in nautical radar images using images collected at the island of Sylt. The edges discernible in the images and the Lipschitz values provide information about the position and nature of spatial variations in the depth of the seafloor. By comparing images from different periods of measurement, temporal changes in the bottom structures can be localized at different resolutions and interpreted. The method is suited to the monitoring of coastal areas. It is an inexpensive way to observe long-term changes in the seafloor character. Thus, the results of this technique may be used by the authorities responsible for coastal protection to decide whether measures should be taken or not. (orig.)

  8. Wave propagation numerical models in damage detection based on the time domain spectral element method

    International Nuclear Information System (INIS)

    Ostachowicz, W; Kudela, P

    2010-01-01

    A Spectral Element Method is used for wave propagation modelling. A 3D solid spectral element is derived with shape functions based on Lagrange interpolation and Gauss-Lobatto-Legendre points. This approach is applied for displacement approximation suited for fundamental modes of Lamb waves as well as potential distribution in piezoelectric transducers. The novelty is the model geometry extension from flat to curved elements for application in shell-like structures. Exemplary visualisations of waves excited by the piezoelectric transducers in curved shell structure made of aluminium alloy are presented. Simple signal analysis of wave interaction with crack is performed. The crack is modelled by separation of appropriate nodes between elements. An investigation of influence of the crack length on wave propagation signals is performed. Additionally, some aspects of the spectral element method implementation are discussed.

  9. On the detection and monitoring of reduced water content in plants using spectral responses in the visible domain

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer; Chen, Tenn F.

    2016-05-01

    The water status of cultivated plants can have a significant impact not only on food production, but also on the appropriate usage of increasingly scarce freshwater supplies. Accordingly, the cost-effective detection and monitoring of changes in their water content are longstanding remote sensing goals. Existing procedures employed to achieve these goals are largely based on the spectral responses of plant leaves in the infrared domain where the light absorption within the foliar tissues is dominated by water. Recently, it has been suggested that such procedures could be implemented using spectral responses, more specifically spectral subsurface reflectance to transmittance ratios, obtained in the visible domain. The basis for this proposition resides on the premise that a reduced water content (RWC) can result in histological changes whose effects on the foliar optical properties may not be limited to the infrared domain. However, the experiments leading to this proposition were performed on detached leaves, which were not influenced by the whole plant's adaptation mechanisms to water stress. In this work, we investigate whether the spectral responses of living plant leaves in the visible domain can lead to reliable RWC estimations. We employ measured biophysical data and predictive light transport simulations in order to extend qualitatively and quantitatively the scope of previous studies in this area. Our findings indicate that the living specimens' physiological responses to water stress should be taken into account in the design of new procedures for the cost-effective RWC estimation using visible subsurface reflectance to transmittance ratios.

  10. Hyperspectral Image-Based Night-Time Vehicle Light Detection Using Spectral Normalization and Distance Mapper for Intelligent Headlight Control

    Directory of Open Access Journals (Sweden)

    Heekang Kim

    2016-07-01

    Full Text Available This paper proposes a vehicle light detection method using a hyperspectral camera instead of a Charge-Coupled Device (CCD or Complementary metal-Oxide-Semiconductor (CMOS camera for adaptive car headlamp control. To apply Intelligent Headlight Control (IHC, the vehicle headlights need to be detected. Headlights are comprised from a variety of lighting sources, such as Light Emitting Diodes (LEDs, High-intensity discharge (HID, and halogen lamps. In addition, rear lamps are made of LED and halogen lamp. This paper refers to the recent research in IHC. Some problems exist in the detection of headlights, such as erroneous detection of street lights or sign lights and the reflection plate of ego-car from CCD or CMOS images. To solve these problems, this study uses hyperspectral images because they have hundreds of bands and provide more information than a CCD or CMOS camera. Recent methods to detect headlights used the Spectral Angle Mapper (SAM, Spectral Correlation Mapper (SCM, and Euclidean Distance Mapper (EDM. The experimental results highlight the feasibility of the proposed method in three types of lights (LED, HID, and halogen.

  11. Impedance spectral fingerprint of E. coli cells on interdigitated electrodes: A new approach for label free and selective detection

    Directory of Open Access Journals (Sweden)

    Maria Mallén-Alberdi

    2016-03-01

    Full Text Available Impedance-based biosensors for bacterial detection offer a rapid and cost-effective alternative to conventional techniques that are time-consuming and require specialized equipment and trained users. In this work, a new bacteria detection scheme is presented based on impedance measurements with antibody-modified polysilicon interdigitated electrodes (3 μm pitch, IDEs. The detection approach was carried out taking advantage of the E. coli structure which, in electrical terms, is constituted by two insulating cell membranes that separate a conductive cytoplasmatic medium and a more conductive periplasm. Impedance detection of bacteria is usually analyzed using electrical equivalent circuit models that show limitations for the interpretation of such complex cell structure. Here, a differential impedance spectrum representation is used to study the unique fingerprint that arises when bacteria attach to the surface of IDEs. That fingerprint shows the dual electrical behavior, insulating and conductive, at different frequency ranges. In parallel, finite-element simulations of this system using a three-shell bacteria model are performed to explain such phenomena. Overall, a new approach to detect bacteria is proposed that also enables to differentiate viable bacteria from other components non-specifically attached to the IDE surface by just detecting their spectral fingerprints. Keywords: Impedance spectroscopy, Bacterial detection, Interdigitated electrodes, Label-free detection, Immuno-detection, E. coli O157:H7

  12. Modeling the Radio Foreground for Detection of CMB Spectral Distortions from the Cosmic Dawn and the Epoch of Reionization

    Energy Technology Data Exchange (ETDEWEB)

    Sathyanarayana Rao, Mayuri; Subrahmanyan, Ravi; Shankar, N Udaya [Raman Research Institute, C V Raman Avenue, Sadashivanagar, Bangalore 560080 (India); Chluba, Jens, E-mail: mayuris@rri.res.in [Jodrell Bank Centre for Astrophysics, University of Manchester, Oxford Road, M13 9PL (United Kingdom)

    2017-05-01

    Cosmic baryon evolution during the Cosmic Dawn and Reionization results in redshifted 21-cm spectral distortions in the cosmic microwave background (CMB). These encode information about the nature and timing of first sources over redshifts 30–6 and appear at meter wavelengths as a tiny CMB distortion along with the Galactic and extragalactic radio sky, which is orders of magnitude brighter. Therefore, detection requires precise methods to model foregrounds. We present a method of foreground fitting using maximally smooth (MS) functions. We demonstrate the usefulness of MS functions over traditionally used polynomials to separate foregrounds from the Epoch of Reionization (EoR) signal. We also examine the level of spectral complexity in plausible foregrounds using GMOSS, a physically motivated model of the radio sky, and find that they are indeed smooth and can be modeled by MS functions to levels sufficient to discern the vanilla model of the EoR signal. We show that MS functions are loss resistant and robustly preserve EoR signal strength and turning points in the residuals. Finally, we demonstrate that in using a well-calibrated spectral radiometer and modeling foregrounds with MS functions, the global EoR signal can be detected with a Bayesian approach with 90% confidence in 10 minutes’ integration.

  13. An Unsupervised Algorithm for Change Detection in Hyperspectral Remote Sensing Data Using Synthetically Fused Images and Derivative Spectral Profiles

    Directory of Open Access Journals (Sweden)

    Youkyung Han

    2017-01-01

    Full Text Available Multitemporal hyperspectral remote sensing data have the potential to detect altered areas on the earth’s surface. However, dissimilar radiometric and geometric properties between the multitemporal data due to the acquisition time or position of the sensors should be resolved to enable hyperspectral imagery for detecting changes in natural and human-impacted areas. In addition, data noise in the hyperspectral imagery spectrum decreases the change-detection accuracy when general change-detection algorithms are applied to hyperspectral images. To address these problems, we present an unsupervised change-detection algorithm based on statistical analyses of spectral profiles; the profiles are generated from a synthetic image fusion method for multitemporal hyperspectral images. This method aims to minimize the noise between the spectra corresponding to the locations of identical positions by increasing the change-detection rate and decreasing the false-alarm rate without reducing the dimensionality of the original hyperspectral data. Using a quantitative comparison of an actual dataset acquired by airborne hyperspectral sensors, we demonstrate that the proposed method provides superb change-detection results relative to the state-of-the-art unsupervised change-detection algorithms.

  14. Automated detection and measurement of isolated retinal arterioles by a combination of edge enhancement and cost analysis.

    Directory of Open Access Journals (Sweden)

    José A Fernández

    Full Text Available Pressure myography studies have played a crucial role in our understanding of vascular physiology and pathophysiology. Such studies depend upon the reliable measurement of changes in the diameter of isolated vessel segments over time. Although several software packages are available to carry out such measurements on small arteries and veins, no such software exists to study smaller vessels (<50 µm in diameter. We provide here a new, freely available open-source algorithm, MyoTracker, to measure and track changes in the diameter of small isolated retinal arterioles. The program has been developed as an ImageJ plug-in and uses a combination of cost analysis and edge enhancement to detect the vessel walls. In tests performed on a dataset of 102 images, automatic measurements were found to be comparable to those of manual ones. The program was also able to track both fast and slow constrictions and dilations during intraluminal pressure changes and following application of several drugs. Variability in automated measurements during analysis of videos and processing times were also investigated and are reported. MyoTracker is a new software to assist during pressure myography experiments on small isolated retinal arterioles. It provides fast and accurate measurements with low levels of noise and works with both individual images and videos. Although the program was developed to work with small arterioles, it is also capable of tracking the walls of other types of microvessels, including venules and capillaries. It also works well with larger arteries, and therefore may provide an alternative to other packages developed for larger vessels when its features are considered advantageous.

  15. Optical perception for detection of cutaneous T-cell lymphoma by multi-spectral imaging

    International Nuclear Information System (INIS)

    Hsiao, Yu-Ping; Wang, Hsiang-Chen; Chen, Shih-Hua; Tsai, Chung-Hung; Yang, Jen-Hung

    2014-01-01

    In this study, the spectrum of each picture element of the patient’s skin image was obtained by multi-spectral imaging technology. Spectra of normal or pathological skin were collected from 15 patients. Principal component analysis and principal component scores of skin spectra were employed to distinguish the spectral characteristics with different diseases. Finally, skin regions with suspected cutaneous T-cell lymphoma (CTCL) lesions were successfully predicted by evaluation and classification of the spectra of pathological skin. The sensitivity and specificity of this technique were 89.65% and 95.18% after the analysis of about 109 patients. The probability of atopic dermatitis and psoriasis patients misinterpreted as CTCL were 5.56% and 4.54%, respectively. (paper)

  16. A Simple Spectral Observer

    Directory of Open Access Journals (Sweden)

    Lizeth Torres

    2018-05-01

    Full Text Available The principal aim of a spectral observer is twofold: the reconstruction of a signal of time via state estimation and the decomposition of such a signal into the frequencies that make it up. A spectral observer can be catalogued as an online algorithm for time-frequency analysis because is a method that can compute on the fly the Fourier transform (FT of a signal, without having the entire signal available from the start. In this regard, this paper presents a novel spectral observer with an adjustable constant gain for reconstructing a given signal by means of the recursive identification of the coefficients of a Fourier series. The reconstruction or estimation of a signal in the context of this work means to find the coefficients of a linear combination of sines a cosines that fits a signal such that it can be reproduced. The design procedure of the spectral observer is presented along with the following applications: (1 the reconstruction of a simple periodical signal, (2 the approximation of both a square and a triangular signal, (3 the edge detection in signals by using the Fourier coefficients, (4 the fitting of the historical Bitcoin market data from 1 December 2014 to 8 January 2018 and (5 the estimation of a input force acting upon a Duffing oscillator. To round out this paper, we present a detailed discussion about the results of the applications as well as a comparative analysis of the proposed spectral observer vis-à-vis the Short Time Fourier Transform (STFT, which is a well-known method for time-frequency analysis.

  17. DETECTION OF ROTATIONAL SPECTRAL VARIATION ON THE M-TYPE ASTEROID (16) PSYCHE

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Juan A.; Thomas, Cristina [Planetary Science Institute, Tucson, AZ 85719 (United States); Reddy, Vishnu [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Shepard, Michael K. [Bloomsburg University, Bloomsburg, PA 17815 (United States); Cloutis, Edward A.; Kiddell, Cain; Applin, Daniel [Department of Geography, University of Winnipeg, Winnipeg, Manitoba (Canada); Takir, Driss [Astrogeology Science Center, U.S. Geological Survey, Flagstaff, AZ 86001 (United States); Conrad, Albert, E-mail: jsanchez@psi.edu [LBT Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2017-01-01

    The asteroid (16) Psyche is of scientific interest because it contains ∼1% of the total mass of the asteroid belt and is thought to be the remnant metallic core of a protoplanet. Radar observations have indicated the significant presence of metal on the surface with a small percentage of silicates. Prior ground-based observations showed rotational variations in the near-infrared (NIR) spectra and radar albedo of this asteroid. However, no comprehensive study that combines multi-wavelength data has been conducted so far. Here we present rotationally resolved NIR spectra (0.7–2.5 μ m) of (16) Psyche obtained with the NASA Infrared Telescope Facility. These data have been combined with shape models of the asteroid for each rotation phase. Spectral band parameters extracted from the NIR spectra show that the pyroxene band center varies from ∼0.92 to 0.94 μ m. Band center values were used to calculate the pyroxene chemistry of the asteroid, whose average value was found to be Fs{sub 30}En{sub 65}Wo{sub 5}. Variations in the band depth (BD) were also observed, with values ranging from 1.0% to 1.5%. Using a new laboratory spectral calibration method, we estimated an average orthopyroxene content of 6% ± 1%. The mass-deficit region of Psyche, which exhibits the highest radar albedo, also shows the highest value for the spectral slope and the minimum BD. The spectral characteristics of Psyche suggest that its parent body did not have the typical structure expected for a differentiated body or that the sequence of events that led to its current state was more complex than previously thought.

  18. DETECTION OF ROTATIONAL SPECTRAL VARIATION ON THE M-TYPE ASTEROID (16) PSYCHE

    International Nuclear Information System (INIS)

    Sanchez, Juan A.; Thomas, Cristina; Reddy, Vishnu; Shepard, Michael K.; Cloutis, Edward A.; Kiddell, Cain; Applin, Daniel; Takir, Driss; Conrad, Albert

    2017-01-01

    The asteroid (16) Psyche is of scientific interest because it contains ∼1% of the total mass of the asteroid belt and is thought to be the remnant metallic core of a protoplanet. Radar observations have indicated the significant presence of metal on the surface with a small percentage of silicates. Prior ground-based observations showed rotational variations in the near-infrared (NIR) spectra and radar albedo of this asteroid. However, no comprehensive study that combines multi-wavelength data has been conducted so far. Here we present rotationally resolved NIR spectra (0.7–2.5 μ m) of (16) Psyche obtained with the NASA Infrared Telescope Facility. These data have been combined with shape models of the asteroid for each rotation phase. Spectral band parameters extracted from the NIR spectra show that the pyroxene band center varies from ∼0.92 to 0.94 μ m. Band center values were used to calculate the pyroxene chemistry of the asteroid, whose average value was found to be Fs 30 En 65 Wo 5 . Variations in the band depth (BD) were also observed, with values ranging from 1.0% to 1.5%. Using a new laboratory spectral calibration method, we estimated an average orthopyroxene content of 6% ± 1%. The mass-deficit region of Psyche, which exhibits the highest radar albedo, also shows the highest value for the spectral slope and the minimum BD. The spectral characteristics of Psyche suggest that its parent body did not have the typical structure expected for a differentiated body or that the sequence of events that led to its current state was more complex than previously thought.

  19. Detection of Rotational Spectral Variation on the M-type Asteroid (16) Psyche

    Science.gov (United States)

    Sanchez, Juan A.; Reddy, Vishnu; Shepard, Michael K.; Thomas, Cristina; Cloutis, Edward A.; Takir, Driss; Conrad, Albert; Kiddell, Cain; Applin, Daniel

    2017-01-01

    The asteroid (16) Psyche is of scientific interest because it contains ˜1% of the total mass of the asteroid belt and is thought to be the remnant metallic core of a protoplanet. Radar observations have indicated the significant presence of metal on the surface with a small percentage of silicates. Prior ground-based observations showed rotational variations in the near-infrared (NIR) spectra and radar albedo of this asteroid. However, no comprehensive study that combines multi-wavelength data has been conducted so far. Here we present rotationally resolved NIR spectra (0.7-2.5 μm) of (16) Psyche obtained with the NASA Infrared Telescope Facility. These data have been combined with shape models of the asteroid for each rotation phase. Spectral band parameters extracted from the NIR spectra show that the pyroxene band center varies from ˜0.92 to 0.94 μm. Band center values were used to calculate the pyroxene chemistry of the asteroid, whose average value was found to be Fs30En65Wo5. Variations in the band depth (BD) were also observed, with values ranging from 1.0% to 1.5%. Using a new laboratory spectral calibration method, we estimated an average orthopyroxene content of 6% ± 1%. The mass-deficit region of Psyche, which exhibits the highest radar albedo, also shows the highest value for the spectral slope and the minimum BD. The spectral characteristics of Psyche suggest that its parent body did not have the typical structure expected for a differentiated body or that the sequence of events that led to its current state was more complex than previously thought.

  20. A cloud shadow detection method combined with cloud height iteration and spectral analysis for Landsat 8 OLI data

    Science.gov (United States)

    Sun, Lin; Liu, Xinyan; Yang, Yikun; Chen, TingTing; Wang, Quan; Zhou, Xueying

    2018-04-01

    Although enhanced over prior Landsat instruments, Landsat 8 OLI can obtain very high cloud detection precisions, but for the detection of cloud shadows, it still faces great challenges. Geometry-based cloud shadow detection methods are considered the most effective and are being improved constantly. The Function of Mask (Fmask) cloud shadow detection method is one of the most representative geometry-based methods that has been used for cloud shadow detection with Landsat 8 OLI. However, the Fmask method estimates cloud height employing fixed temperature rates, which are highly uncertain, and errors of large area cloud shadow detection can be caused by errors in estimations of cloud height. This article improves the geometry-based cloud shadow detection method for Landsat OLI from the following two aspects. (1) Cloud height no longer depends on the brightness temperature of the thermal infrared band but uses a possible dynamic range from 200 m to 12,000 m. In this case, cloud shadow is not a specific location but a possible range. Further analysis was carried out in the possible range based on the spectrum to determine cloud shadow location. This effectively avoids the cloud shadow leakage caused by the error in the height determination of a cloud. (2) Object-based and pixel spectral analyses are combined to detect cloud shadows, which can realize cloud shadow detection from two aspects of target scale and pixel scale. Based on the analysis of the spectral differences between the cloud shadow and typical ground objects, the best cloud shadow detection bands of Landsat 8 OLI were determined. The combined use of spectrum and shape can effectively improve the detection precision of cloud shadows produced by thin clouds. Several cloud shadow detection experiments were carried out, and the results were verified by the results of artificial recognition. The results of these experiments indicated that this method can identify cloud shadows in different regions with correct

  1. Onset of nucleate boiling and onset of fully developed subcooled boiling detection using pressure transducers signals spectral analysis

    International Nuclear Information System (INIS)

    Maprelian, Eduardo; Castro, Alvaro Alvim de; Ting, Daniel Kao Sun

    1999-01-01

    The experimental technique used for detection of subcooled boiling through analysis of the fluctuation contained in pressure transducers signals is presented. The experimental part of this work was conducted at the Institut fuer Kerntechnik und zertoerungsfreie Pruefverfahren von Hannover (IKPH, Germany) in a thermal-hydraulic circuit with one electrically heated rod with annular geometry test section. Piezo resistive pressure sensors are used for onset of nucleate boiling (ONB) and onset of fully developed boiling (OFDB) detection using spectral analysis/signal correlation techniques. Experimental results are interpreted by phenomenological analysis of these two points and compared with existing correlation. The results allows us to conclude that this technique is adequate for the detection and monitoring of the ONB and OFDB. (author)

  2. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  3. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  4. Land cover change detection using the internal covariance matrix of the extended kalman filter over multiple spectral bands

    CSIR Research Space (South Africa)

    Salmon

    2013-06-01

    Full Text Available stream_source_info Salmon_10577_2013.pdf.txt stream_content_type text/plain stream_size 1183 Content-Encoding ISO-8859-1 stream_name Salmon_10577_2013.pdf.txt Content-Type text/plain; charset=ISO-8859-1 IEEE Journal... of Selected Topics in Applied Earth Observations and Remote Sensing, vol, 6(3): 1079- 1085 Land cover change detection using the internal covariance matrix of the extended kalman filter over multiple spectral bands Salmon BP Kleynhans W Van den Bergh...

  5. Using Image Texture and Spectral Reflectance Analysis to Detect Yellowness and Esca in Grapevines at Leaf-Level

    Directory of Open Access Journals (Sweden)

    Hania Al-Saddik

    2018-04-01

    Full Text Available Plant diseases are one of the main reasons behind major economic and production losses in the agricultural field. Current research activities enable large fields monitoring and plant disease detection using innovative and robust technologies. French grapevines have a reputation for producing premium quality wines, however, these major fruit crops are susceptible to many diseases, including Esca, Downy mildew, Powdery mildew, Yellowing, and many others. In this study, we focused on two main infections (Esca and Yellowing, and data were gathered from fields that were located in Aquitaine and Burgundy regions, France. Since plant diseases can be diagnosed from the properties of the leaf, we acquired both Red-Green-Blue (RGB digital image and hyperspectral reflectance data from infected and healthy leaves. Biophysical parameters that were produced by the PROSPECT model inversion together with texture parameters compiled from the literature were deduced. Then we investigated their relationship to damage caused by Yellowing and Esca. This study examined whether spectral and textural data can identify the two diseases through the use of Neural Networks. We obtained an overall accuracy of 99% for both of the diseases when textural and spectral data are combined. These results suggest that, first, biophysical parameters present a valid dimension reduction tool that could replace the use of complete hyperspectral data. Second, remote sensing using spectral reflectance and digital images can make an overall nondestructive, rapid, cost-effective, and reproducible technique to determine diseases in grapevines with a good level of accuracy.

  6. Improved covariance matrix estimation in spectrally inhomogeneous sea clutter with application to adaptive small boat detection.

    CSIR Research Space (South Africa)

    Herselman, PL

    2008-09-01

    Full Text Available and that is necessary to set the threshold χt as a function of the steering vector Doppler fd. Improvements to the estimation technique are suggested and evaluated where a more localised M is estimated using either frequency agility or the immediate time history... of frequency, calculated as NIM2(fd) = E{z(fd)2}/E2{z(fd)} , (3) where z(fd) is the power spectral density at fd. This is often used to quantify the Rayleigh-likeness of the envelope 0 5 10 15 −500 −250 0 250 500 Doppler frequency [Hz ] NIM2Time [s...

  7. Spectral Editing Technique for the in Vitroand in VivoDetection of Taurine

    Science.gov (United States)

    Hardy, D. L.; Norwood, T. J.

    1998-07-01

    In vivo1H NMR spectroscopy has proven to be a useful noninvasive tool for the investigation of numerous metabolic and physiological states. Taurine is potentially a useful indicator in neonate development and is involved in a number of physiological processes. However, it could not previously be observed in thein vivo1H spectrum because of overlap with adjacent resonances. We have developed a spectral editing technique based upon double quantum filtration which allows the taurine resonances to be resolved from adjacent peaks. The experiment is demonstrated both on perchloric acid rodent brain extract and on rodent brain homogenate.

  8. Edge Detection Algorithm Based on Fuzzy Logic Theory for a Local Vision System of Robocup Humanoid League

    Directory of Open Access Journals (Sweden)

    Andrea K. Perez-Hernandez

    2013-06-01

    Full Text Available At this paper we shown the development of an algorithm to perform edges extraction based on fuzzy logic theory. This method allows recognizing landmarks on the game field for Humanoid League of RoboCup. The proposed algorithm describes the creation of a fuzzy inference system that permit evaluate the existent relationship between image pixels, finding variations on grey levels of related neighbor pixels. Subsequently, it shows an implementation of OTSU method to binarize an image that was obtained from fuzzy process and so generate an image containing only extracted edges, validating the algorithm with Humanoid League images. Later, we analyze obtained results that evidence a good performance of algorithm, considering that this proposal only takes an extra 35% processing time that will be required by traditional methods, whereas extracted edges are 52% less noise susceptible.

  9. SPECTRAL PROPERTIES OF BRIGHT FERMI-DETECTED BLAZARS IN THE GAMMA-RAY BAND

    International Nuclear Information System (INIS)

    Abdo, A. A.; Ackermann, M.; Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Bouvier, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Bellazzini, R.; Bregeon, J.; Brez, A.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bonamente, E.; Brigida, M.

    2010-01-01

    The gamma-ray energy spectra of bright blazars of the LAT Bright AGN Sample (LBAS) are investigated using Fermi-LAT data. Spectral properties (hardness, curvature, and variability) established using a data set accumulated over 6 months of operation are presented and discussed for different blazar classes and subclasses: flat spectrum radio quasars (FSRQs), low-synchrotron peaked BLLacs (LSP-BLLacs), intermediate-synchrotron peaked BLLacs (ISP-BLLacs), and high-synchrotron peaked BLLacs (HSP-BLLacs). The distribution of photon index (Γ, obtained from a power-law fit above 100 MeV) is found to correlate strongly with blazar subclass. The change in spectral index from that averaged over the 6 months observing period is < 0.2-0.3 when the flux varies by about an order of magnitude, with a tendency toward harder spectra when the flux is brighter for FSRQs and LSP-BLLacs. A strong departure from a single power-law spectrum appears to be a common feature for FSRQs. This feature is also present for some high-luminosity LSP-BLLacs, and a small number of ISP-BLLacs. It is absent in all LBAS HSP-BLLacs. For 3C 454.3 and AO 0235+164, the two brightest FSRQ source and LSP-BLLac source, respectively, a broken power law (BPL) gives the most acceptable of power law, BPL, and curved forms. The consequences of these findings are discussed.

  10. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size.

    Science.gov (United States)

    Fallenberg, E M; Dromain, C; Diekmann, F; Engelken, F; Krohn, M; Singh, J M; Ingold-Heppner, B; Winzer, K J; Bick, U; Renz, D M

    2014-01-01

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography (CESM) is slowly being introduced into clinical practice. • Access to breast MRI is limited by availability and lack of reimbursement. • Initial results show a better sensitivity of CESM and MRI than conventional mammography. • CESM showed a good correlation with postoperative histology in size assessment. • Contrast-enhanced spectral mammography offers promise, seemingly providing information comparable to MRI.

  11. Effects of higher-coordination shells in garnets detected by XAS at the Al K-edge

    International Nuclear Information System (INIS)

    Marcelli, A.; Wu, Z.; Mottana, A.; Giuli, G.; Paris, E.; Seifert, F.

    1996-03-01

    The aluminium 1 s x-ray-absorption spectra of a series of garnets, pyrope, almandine, spessartine and grossular, are compared to full multiple-scattering calculation using cluster models. An overall good agreement between experiment and calculation, extended also to the edge region,is obtained in the energy range in up to 60 e V above the threshold, provided cluster containing at least 40 atoms are used. The analysis of these garnet XAS spectra provides clear evidence on the effect of probe, XANES spectroscopy at the edge of low Z elements appears to be a perfect tool to investigate the role played by atoms located in higher-coordination shells

  12. Effects of higher-coordination shells in garnets detected by XAS at the Al K-edge

    Energy Technology Data Exchange (ETDEWEB)

    Marcelli, A. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Wu, Z. [CNRS UMR 110, Laboratoire de Chimie des Solides, Nantes Cedex (France). Institut de materiaux de Nantes; Mottana, A. [Roma III Univ., Rome (Italy). Dipartimento di Scienze Geologiche; Giuli, G.; Paris, E. [Camerino Univ., Camerino (Italy).Diparimento di Scienze della Terra; Seifert, F [Univ. Bayreuth, Bayreuth (Italy). Bayerisches Geoinstitut (Germany)

    1996-03-01

    The aluminium 1 s x-ray-absorption spectra of a series of garnets, pyrope, almandine, spessartine and grossular, are compared to full multiple-scattering calculation using cluster models. An overall good agreement between experiment and calculation, extended also to the edge region,is obtained in the energy range in up to 60 e V above the threshold, provided cluster containing at least 40 atoms are used. The analysis of these garnet XAS spectra provides clear evidence on the effect of probe, XANES spectroscopy at the edge of low Z elements appears to be a perfect tool to investigate the role played by atoms located in higher-coordination shells.

  13. Reducing BER of spectral-amplitude coding optical code-division multiple-access systems by single photodiode detection technique

    Science.gov (United States)

    Al-Khafaji, H. M. R.; Aljunid, S. A.; Amphawan, A.; Fadhil, H. A.; Safar, A. M.

    2013-03-01

    In this paper, we present a single photodiode detection (SPD) technique for spectral-amplitude coding optical code-division multiple-access (SAC-OCDMA) systems. The proposed technique eliminates both phase-induced intensity noise (PIIN) and multiple-access interference (MAI) in the optical domain. Analytical results show that for 35 simultaneous users transmitting at data rate of 622 Mbps, the bit-error rate (BER) = 1.4x10^-28 for SPD technique is much better compared to 9.3x10^-6 and 9.6x10^-3 for the modified-AND as well as the AND detection techniques, respectively. Moreover, we verified the improved performance afforded by the proposed technique using data transmission simulations.

  14. Detection of corn and weed species by the combination of spectral, shape and textural features

    Science.gov (United States)

    Accurate detection of weeds in farmland can help reduce pesticide use and protect the agricultural environment. To develop intelligent equipment for weed detection, this study used an imaging spectrometer system, which supports micro-scale plant feature analysis by acquiring high-resolution hyper sp...

  15. Detection of crop water status in mature olive orchards using vegetation spectral measurements

    Science.gov (United States)

    Rallo, Giovanni; Ciraolo, Giuseppe; Farina, Giuseppe; Minacapilli, Mario; Provenzano, Giuseppe

    2013-04-01

    Leaf/stem water potentials are generally considered the most accurate indicators of crop water status (CWS) and they are quite often used for irrigation scheduling, even if costly and time-consuming. For this reason, in the last decade vegetation spectral measurements have been proposed, not only for environmental monitoring, but also in precision agriculture, to evaluate crop parameters and consequently for irrigation scheduling. Objective of the study was to assess the potential of hyperspectral reflectance (450-2400 nm) data to predict the crop water status (CWS) of a Mediterranean olive orchard. Different approaches were tested and particularly, (i) several standard broad- and narrow-band vegetation indices (VIs), (ii) specific VIs computed on the basis of some key wavelengths, predetermined by simple correlations and finally, (iii) using partial least squares (PLS) regression technique. To this aim, an intensive experimental campaign was carried out in 2010 and a total of 201 reflectance spectra, at leaf and canopy level, were collected with an ASD FieldSpec Pro (Analytical Spectral Devices, Inc.) handheld field spectroradiometer. CWS was contemporarily determined by measuring leaf and stem water potentials with the Scholander chamber. The results indicated that the considered standard vegetation indices were weakly correlated with CWS. On the other side, the prediction of CWS can be improved using VIs pointed to key-specific wavelengths, predetermined with a correlation analysis. The best prediction accuracy, however, can be achieved with models based on PLS regressions. The results confirmed the dependence of leaf/canopy optical features from CWS so that, for the examined crop, the proposed methodology can be considered a promising tool that could also be extended for operational applications using multispectral aerial sensors.

  16. [Colon adenoma detection using Kubelka-Munk spectral function of DNA and protein bands].

    Science.gov (United States)

    Wei, Hua-Jiang; Guo, Zhou-Yi; Xie, Shu-Sen; He, Bo-Hua; Li, Li-Bo; Chen, Xue-Mei; Wu, Guo-Yong; Lu, Jian-Jun

    2009-06-01

    Differential diagnosis of human colon adenoma was studied using the Kubelka-Munk spectral function of the DNA and protein absorption bands at 260 and 280 nm in vitro. Diffuse reflectance spectra of tissue were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that for the spectral range from 590 to 1 064 nm pathological changes of colon epithelial tissues were induced so that there were significant differences in the averaged values of the Kubelka-Munk function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the DNA absorption bands at 260 nm between normal and adenomatous colon epithelial tissues, and the differences were 218% (p function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the protein absorption bands at 280 nm between normal and adenomatous colon epithelial tissues, and the differences were 208% (p function f(r infinity) and logarithmic Kubelka-Munk function log [f(r infinity)] of the beta-carotene absorption bands at 480 nm between normal and adenomatous colon epithelial tissues, and the differences were 41.7% (p < 0.05) and 32.9% (p < 0.05) respectively. Obviously, pathological changes of colon epithelial tissues were induced so that there were significant changes in the contents of the DNA, protein and beta-carotene of colon epithelial tissues. The conclusion can be applied to rapid, low-cost and noninvasive optical biopsy of colon adenoma, and provides a useful reference.

  17. Detection of X-ray spectral state transitions in mini-outbursts of black hole transient GRS 1739-278

    Science.gov (United States)

    Yan, Zhen; Yu, Wenfei

    2017-10-01

    We report the detection of the state transitions and hysteresis effect in the two mini-outbursts of the black hole (BH) transient GRS 1739-278 following its 2014 major outburst. The X-ray spectral evolutions in these two mini-outbursts are similar to the major outburst in spite of their peak luminosities and the outburst durations are one order of magnitude lower. We found L_hard{-to-soft} and Lpeak,soft of the mini-outbursts also follow the correlation previously found in other X-ray binaries. L_hard{-to-soft} of the mini-outbursts is still higher than that of the persistent BH binary Cyg X-1, which supports that there is a link between the maximum luminosity a source can reach in the hard state and the corresponding non-stationary accretion represented by substantial rate of change in the mass accretion rate during flares/outbursts. The detected luminosity range of these two mini-outbursts is roughly in 3.5 × 10-5 to 0.015 (D/7.5 kpc)2(M/8M⊙) LEdd. The X-ray spectra of other BH transients at such low luminosities are usually dominated by a power-law component, and an anti-correlation is observed between the photon index and the X-ray luminosity below 1 per cent LEdd. So, the detection of X-ray spectral state transitions indicates that the accretion flow evolution in these two mini-outbursts of GRS 1739-278 are different from other BH systems at such low-luminosity regime.

  18. Bacterial detection using bacteriophages and gold nanorods by following time-dependent changes in Raman spectral signals.

    Science.gov (United States)

    Moghtader, Farzaneh; Tomak, Aysel; Zareie, Hadi M; Piskin, Erhan

    2018-03-27

    This study attemps to develop bacterial detection strategies using bacteriophages and gold nanorods (GNRs) by Raman spectral analysis. Escherichia coli was selected as the target and its specific phage was used as the bioprobe. Target bacteria and phages were propagated/purified by traditional techniques. GNRs were synthesized by using hexadecyltrimethyl ammonium bromide (CTAB) as stabilizer. A two-step detection strategy was applied: Firstly, the target bacteria were interacted with GNRs in suspensions, and then they were dropped onto silica substrates for detection. It was possible to obtain clear surface-enchanced Raman spectroscopy (SERS) peaks of the target bacteria, even without using phages. In the second step, the phage nanoemulsions were droped onto the bacterial-GNRs complexes on those surfaces and time-dependent changes in the Raman spectra were monitored at different time intervals upto 40 min. These results demonstrated that how one can apply phages with plasmonic nanoparticles for detection of pathogenic bacteria very effectively in a quite simple test.

  19. Real-time detection of organic contamination events in water distribution systems by principal components analysis of ultraviolet spectral data.

    Science.gov (United States)

    Zhang, Jian; Hou, Dibo; Wang, Ke; Huang, Pingjie; Zhang, Guangxin; Loáiciga, Hugo

    2017-05-01

    The detection of organic contaminants in water distribution systems is essential to protect public health from potential harmful compounds resulting from accidental spills or intentional releases. Existing methods for detecting organic contaminants are based on quantitative analyses such as chemical testing and gas/liquid chromatography, which are time- and reagent-consuming and involve costly maintenance. This study proposes a novel procedure based on discrete wavelet transform and principal component analysis for detecting organic contamination events from ultraviolet spectral data. Firstly, the spectrum of each observation is transformed using discrete wavelet with a coiflet mother wavelet to capture the abrupt change along the wavelength. Principal component analysis is then employed to approximate the spectra based on capture and fusion features. The significant value of Hotelling's T 2 statistics is calculated and used to detect outliers. An alarm of contamination event is triggered by sequential Bayesian analysis when the outliers appear continuously in several observations. The effectiveness of the proposed procedure is tested on-line using a pilot-scale setup and experimental data.

  20. Application of Novel Software Algorithms to Spectral-Domain Optical Coherence Tomography for Automated Detection of Diabetic Retinopathy.

    Science.gov (United States)

    Adhi, Mehreen; Semy, Salim K; Stein, David W; Potter, Daniel M; Kuklinski, Walter S; Sleeper, Harry A; Duker, Jay S; Waheed, Nadia K

    2016-05-01

    To present novel software algorithms applied to spectral-domain optical coherence tomography (SD-OCT) for automated detection of diabetic retinopathy (DR). Thirty-one diabetic patients (44 eyes) and 18 healthy, nondiabetic controls (20 eyes) who underwent volumetric SD-OCT imaging and fundus photography were retrospectively identified. A retina specialist independently graded DR stage. Trained automated software generated a retinal thickness score signifying macular edema and a cluster score signifying microaneurysms and/or hard exudates for each volumetric SD-OCT. Of 44 diabetic eyes, 38 had DR and six eyes did not have DR. Leave-one-out cross-validation using a linear discriminant at missed detection/false alarm ratio of 3.00 computed software sensitivity and specificity of 92% and 69%, respectively, for DR detection when compared to clinical assessment. Novel software algorithms applied to commercially available SD-OCT can successfully detect DR and may have potential as a viable screening tool for DR in future. [Ophthalmic Surg Lasers Imaging Retina. 2016;47:410-417.]. Copyright 2016, SLACK Incorporated.

  1. [Gastric cancer detection using kubelka-Munk spectral function of DNA and protein absorption bands].

    Science.gov (United States)

    Li, Lan-quan; Wei, Hua-jiang; Guo, Zhou-yi; Yang, Hong-qin; Xie, Shu-sen; Chen, Xue-mei; Li, Li-bo; He, Bol-hua; Wu, Guo-yong; Lu, Jian-jun

    2009-09-01

    Differential diagnosis for epithelial tissues of normal human gastric, undifferentiation gastric adenocarcinoma, gastric squamous cell carcinomas, and poorly differentiated gastric adenocarcinoma were studied using the Kubelka-Munk spectral function of the DNA and protein absorption bands at 260 and 280 nm in vitro. Diffuse reflectance spectra of tissue were measured using a spectrophotometer with an integrating sphere attachment. The results of measurement showed that for the spectral range from 250 to 650 nm, pathological changes of gastric epithelial tissues induced that there were significant differences in the averaged value of the Kubelka-Munk function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the DNA absorption bands at 260 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 68.5% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the protein absorption bands at 280 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 86.8% (p function f(r infinity) and logarithmic Kubelka-Munk function log[f(r infinity)] of the carotene absorption bands at 480 nm between epithelial tissues of normal human stomach and human undifferentiation gastric cancer, between epithelial tissues of normal human stomach and human gastric squamous cell carcinomas, and between epithelial tissues of normal human stomach and human poorly differentiated cancer. Their differences were 59.5% (p < 0.05), 73% (p < 0

  2. method for ranging and noise reduction of low coherence interferometry LCI and optical coherence tomography OCT signals by parallel detection of spectral bands

    NARCIS (Netherlands)

    Boer, JF De; Tearney, G. J.; Bouma, BE

    2008-01-01

    Apparatus and method for increasing the sensitivity in the detection of optical coherence tomography and loW coher ence interferometry (“LCI”) signals by detecting a parallel set of spectral bands, each band being a unique combination of optical frequencies. The LCI broad bandwidth source is split

  3. Spectral and physiological information from chlorophyll fluorescence signals in the detection of pine damage

    Energy Technology Data Exchange (ETDEWEB)

    Meinander, O. [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.; Somersalo, S. [Helsinki Univ., Helsinki (Finland). Dept. of Plant Biology

    1995-12-31

    Photosynthesis is often among the first targets of the air pollution stress of plants. As chlorophyll fluorescence is a process competing with photosynthetic electron transport it can be employed to study the potential photosynthetic capacity and to detect damage to the photosynthetic apparatus. Many previous studies have shown that chlorophyll fluorescence can be a powerful tool in the detection of forest damage. In this preliminary study, singular value analysis of the fluorescence induction curves was used together with the traditional way of analyzing fluorescence measurements. The experimental data were collected from ozone and carbon dioxide fumigated Scots pine saplings. (author)

  4. Spectral and physiological information from chlorophyll fluorescence signals in the detection of pine damage

    Energy Technology Data Exchange (ETDEWEB)

    Meinander, O [Finnish Meteorological Inst., Helsinki (Finland). Air Quality Dept.; Somersalo, S [Helsinki Univ., Helsinki (Finland). Dept. of Plant Biology

    1996-12-31

    Photosynthesis is often among the first targets of the air pollution stress of plants. As chlorophyll fluorescence is a process competing with photosynthetic electron transport it can be employed to study the potential photosynthetic capacity and to detect damage to the photosynthetic apparatus. Many previous studies have shown that chlorophyll fluorescence can be a powerful tool in the detection of forest damage. In this preliminary study, singular value analysis of the fluorescence induction curves was used together with the traditional way of analyzing fluorescence measurements. The experimental data were collected from ozone and carbon dioxide fumigated Scots pine saplings. (author)

  5. Liver Status Assessment by Spectrally and Time Resolved IR Detection of Drug Induced Breath Gas Changes

    Directory of Open Access Journals (Sweden)

    Tom Rubin

    2016-05-01

    Full Text Available The actual metabolic capacity of the liver is crucial for disease identification, liver therapy, and liver tumor resection. By combining induced drug metabolism and high sensitivity IR spectroscopy of exhaled air, we provide a method for quantitative liver assessment at bedside within 20 to 60 min. Fast administration of 13C-labelled methacetin induces a fast response of liver metabolism and is tracked in real-time by the increase of 13CO2 in exhaled air. The 13CO2 concentration increase in exhaled air allows the determination of the metabolic liver capacity (LiMAx-test. Fluctuations in CO2 concentration, pressure and temperature are minimized by special gas handling, and tracking of several spectrally resolved CO2 absorption bands with a quantum cascade laser. Absorption measurement of different 12CO2 and 13CO2 rotation-vibration transitions in the same time window allows for multiple referencing and reduction of systematic errors. This FLIP (Fast liver investigation package setup is being successfully used to plan operations and determine the liver status of patients.

  6. A new physics-based method for detecting weak nuclear signals via spectral decomposition

    International Nuclear Information System (INIS)

    Chan, Kung-Sik; Li, Jinzheng; Eichinger, William; Bai, Erwei

    2012-01-01

    We propose a new physics-based method to determine the presence of the spectral signature of one or more nuclides from a poorly resolved spectra with weak signatures. The method is different from traditional methods that rely primarily on peak finding algorithms. The new approach considers each of the signatures in the library to be a linear combination of subspectra. These subspectra are obtained by assuming a signature consisting of just one of the unique gamma rays emitted by the nuclei. We propose a Poisson regression model for deducing which nuclei are present in the observed spectrum. In recognition that a radiation source generally comprises few nuclear materials, the underlying Poisson model is sparse, i.e. most of the regression coefficients are zero (positive coefficients correspond to the presence of nuclear materials). We develop an iterative algorithm for a penalized likelihood estimation that prompts sparsity. We illustrate the efficacy of the proposed method by simulations using a variety of poorly resolved, low signal-to-noise ratio (SNR) situations, which show that the proposed approach enjoys excellent empirical performance even with SNR as low as to -15 db.

  7. Spectral imaging technique for retinal perfusion detection using confocal scanning laser ophthalmoscopy

    Science.gov (United States)

    Rasta, Seyed Hossein; Manivannan, Ayyakkannu; Sharp, Peter F.

    2012-11-01

    To evaluate retinal perfusion in the human eye, a dual-wavelength confocal scanning laser ophthalmoscope (cSLO) was developed that provides spectral imaging of the fundus using a combination of red (670 nm) and near-infrared (810 nm) wavelengths. The image of the ocular fundus was analyzed to find out if quantitative measurements of the reflectivity of tissue permit assessment of the oxygen perfusion of tissue. We explored problems that affect the reproducibility of patient measurements such as non-uniformity errors on the image. For the first time, an image processing technique was designed and used to minimize the errors of oxygen saturation measurements by illumination correction in retina wide field by increasing SNR. Retinal images were taken from healthy and diabetic retinopathy eyes using the cSLO with a confocal aperture of 100 μm. The ratio image (RI) of red/IR, as oxygen saturation (SO2) index, was calculated for normal eyes. The image correction technique improved the reproducibility of the measurements. Average RI intensity variation of healthy retina tissue was determined within a range of about 5.5%. The capability of the new technique to discriminate oxygenation levels of retinal artery and vein was successfully demonstrated and showed good promise in the diagnosis of the perfused retina.

  8. A construction of standardized near infrared hyper-spectral teeth database: a first step in the development of reliable diagnostic tool for quantification and early detection of caries

    Science.gov (United States)

    Bürmen, Miran; Usenik, Peter; Fidler, Aleš; Pernuš, Franjo; Likar, Boštjan

    2011-03-01

    Dental caries is a disease characterized by demineralization of enamel crystals leading to the penetration of bacteria into the dentin and pulp. If left untreated, the disease can lead to pain, infection and tooth loss. Early detection of enamel demineralization resulting in increased enamel porosity, commonly known as white spots, is a difficult diagnostic task. Several papers reported on near infrared (NIR) spectroscopy to be a potentially useful noninvasive spectroscopic technique for early detection of caries lesions. However, the conducted studies were mostly qualitative and did not include the critical assessment of the spectral variability of the sound and carious dental tissues and influence of the water content. Such assessment is essential for development and validation of reliable qualitative and especially quantitative diagnostic tools based on NIR spectroscopy. In order to characterize the described spectral variability, a standardized diffuse reflectance hyper-spectral database was constructed by imaging 12 extracted human teeth with natural lesions of various degrees in the spectral range from 900 to 1700 nm with spectral resolution of 10 nm. Additionally, all the teeth were imaged by digital color camera. The influence of water content on the acquired spectra was characterized by monitoring the teeth during the drying process. The images were assessed by an expert, thereby obtaining the gold standard. By analyzing the acquired spectra we were able to accurately model the spectral variability of the sound dental tissues and identify the advantages and limitations of NIR hyper-spectral imaging.

  9. Spectral analysis of geological materials in the Central Volcanic Range of Costa Rica and its relationship to the remote detection of anomalies

    OpenAIRE

    Rejas, J. G.; Martínez-Frías, J.; Martínez, R.; Bonatti, J.

    2014-01-01

    The aim of this work is the comparative study of methods for calculating spectral anomalies from imaging spectrometry in several test areas of the Central Volcanic Range (CVR) of Costa Rica. In the detection of anomalous responses it is assumed no prior knowledge of the targets, so that the pixels are automatically separated according to their spectral information significantly differentiated with respect to a background to be estimated, either globally for the full scene, either locally by i...

  10. Detection of Pb-LIII edge XANES spectra of urban atmospheric particles combined with simple acid extraction

    International Nuclear Information System (INIS)

    Funasaka, K.; Tojo, T.; Katahira, K.; Shinya, M.; Miyazaki, T.; Kamiura, T.; Yamamoto, O.; Moriwaki, H.; Tanida, H.; Takaoka, M.

    2008-01-01

    Pb-LIII edge XANES spectra of atmospheric particles are directly obtained by fluorescent XAFS spectroscopy using a 19-element solid state detector (SSD). Particulate sample was collected on a quartz fiber filter using a high-volume air sampler, and the filter was cut into small pieces (25 x 25 mm). Then, surface layer of the filter piece was scaled and accumulated in order to enhance the particle density per filter unit. Use of 10 pieces of the surface layer enables the measurement of Pb-LIII edge XANES spectra on beamline BL01B1 at SPring-8, Hyogo, Japan. The shape of the Pb-LIII edge XANES spectra of the particulate sample is similar to the shapes of the spectra for PbS, PbCO 3 , PbSO 4 and/or PbCl 2 . Additionally, the filter sample is also divided into water-soluble, 0.1 M HCl-extractable, and residual fractions of Pb compounds by a simple acid extraction procedure. We discuss the possibility of Pb speciation in the particulate samples with combination of highly sensitive XANES spectroscopy and simple acid extraction

  11. Assessing the potential of spectral induced polarization to detect in situ changes in iron reduction

    Science.gov (United States)

    Rosier, C. L.; Price, A.; Sharma, S.; Atekwana, E. A.

    2016-12-01

    The near surface geophysical technique Spectral Induced Polarization (SIP), provides promise as an effective method measuring in situ biofilm formation/development. Yet, potential mechanisms responsible for observed shifts in SIP response due to biofilm are not clearly understood. In order to address possible mechanisms we assessed the influence of Shewanella oneidensis (MR1) cell density (colony forming units; CFU), biofilm production (Bradford assay) and iron reduction metabolism (colorimetric assay) on SIP response. Laboratory measurements were collected over three months on columns packed with either iron-coated or iron-free sands and amended with artificial ground water and acetate in order to stimulate biofilm production and microbial iron reduction. Additionally, scanning electron microscopy (SEM) was used to confirm the presence of S. oneidensis cells and biofilm. Our results suggest that during early/initial stage (75 days) of column incubation, SIP measurements revealed that phase and imaginary conductivity responses decreased as the concentration of reduced iron decreased below 2.0 mM. In contrast, we observed only a moderate increase in phase and imaginary conductivity ( 30%) within iron-free columns as a result of increases in S. oneidensis cells (CFU 1.5 x 1011) and biofilm production (7.0 mg ml-1). SEM analysis confirmed the presence of biofilm and cells within both iron-coated and iron-free columns. We hypothesize that the production of microbial metabolic byproducts is a potential mechanism explaining large phase shits observed in previous studies ( 50 mrads) rather than the conductivity of cells or biofilm. Our findings provide support for the following: i) ratio of cells to biofilm production only moderately influences both phase and imaginary conductivity response and ii) largest phase and imaginary conductivity response resulted from microbial metabolism (i.e. iron reduction) and potentially biofilm trapping of conductive materials (i

  12. Underwater Cylindrical Object Detection Using the Spectral Features of Active Sonar Signals with Logistic Regression Models

    Directory of Open Access Journals (Sweden)

    Yoojeong Seo

    2018-01-01

    Full Text Available The issue of detecting objects bottoming on the sea floor is significant in various fields including civilian and military areas. The objective of this study is to investigate the logistic regression model to discriminate the target from the clutter and to verify the possibility of applying the model trained by the simulated data generated by the mathematical model to the real experimental data because it is not easy to obtain sufficient data in the underwater field. In the first stage of this study, when the clutter signal energy is so strong that the detection of a target is difficult, the logistic regression model is employed to distinguish the strong clutter signal and the target signal. Previous studies have found that if the clutter energy is larger, false detection occurs even for the various existing detection schemes. For this reason, the discrete Fourier transform (DFT magnitude spectrum of acoustic signals received by active sonar is applied to train the model to distinguish whether the received signal contains a target signal or not. The goodness of fit of the model is verified in terms of receiver operation characteristic (ROC, area under ROC curve (AUC, and classification table. The detection performance of the proposed model is evaluated in terms of detection rate according to target to clutter ratio (TCR. Furthermore, the real experimental data are employed to test the proposed approach. When using the experimental data to test the model, the logistic regression model is trained by the simulated data that are generated based on the mathematical model for the backscattering of the cylindrical object. The mathematical model is developed according to the size of the cylinder used in the experiment. Since the information on the experimental environment including the sound speed, the sediment type and such is not available, once simulated data are generated under various conditions, valid simulated data are selected using 70% of the

  13. Enzyme catalytic resonance scattering spectral detection of trace hydrogen peroxide using guaiacol as substrate

    Directory of Open Access Journals (Sweden)

    Shiwen Huang

    2011-08-01

    Full Text Available Hydrogen peroxide oxidized guaiacol to form tetramer particles that exhibited a strong resonance scattering (RS peak at 530 nm in the presence of horseradish peroxidase (HRP in citric acid-Na2HPO4 buffer solution of pH 4.4. The RS peak increased when the concentration of hydrogen peroxide increased. The increased RS intensity (ΔI530 nm was linear to the hydrogen peroxide concentration in the range of 0.55-27.6 μM, with a linear regression equation of ΔI530 nm = 17.1C + 1.6, a relative coefficient of 0.9996 and a detection limit of 0.03 μM H2O2. This proposed method was applied to detect hydrogen peroxide in rain water, with sensitivity, selectivity, rapidity, and recovery of 98.0-104 %.

  14. Using VIS/NIR and IR spectral cameras for detecting and separating crime scene details

    Science.gov (United States)

    Kuula, Jaana; Pölönen, Ilkka; Puupponen, Hannu-Heikki; Selander, Tuomas; Reinikainen, Tapani; Kalenius, Tapani; Saari, Heikki

    2012-06-01

    Detecting invisible details and separating mixed evidence is critical for forensic inspection. If this can be done reliably and fast at the crime scene, irrelevant objects do not require further examination at the laboratory. This will speed up the inspection process and release resources for other critical tasks. This article reports on tests which have been carried out at the University of Jyväskylä in Finland together with the Central Finland Police Department and the National Bureau of Investigation for detecting and separating forensic details with hyperspectral technology. In the tests evidence was sought after at an assumed violent burglary scene with the use of VTT's 500-900 nm wavelength VNIR camera, Specim's 400- 1000 nm VNIR camera, and Specim's 1000-2500 nm SWIR camera. The tested details were dried blood on a ceramic plate, a stain of four types of mixed and absorbed blood, and blood which had been washed off a table. Other examined details included untreated latent fingerprints, gunshot residue, primer residue, and layered paint on small pieces of wood. All cameras could detect visible details and separate mixed paint. The SWIR camera could also separate four types of human and animal blood which were mixed in the same stain and absorbed into a fabric. None of the cameras could however detect primer residue, untreated latent fingerprints, or blood that had been washed off. The results are encouraging and indicate the need for further studies. The results also emphasize the importance of creating optimal imaging conditions into the crime scene for each kind of subjects and backgrounds.

  15. Damage detection on mesosurfaces using distributed sensor network and spectral diffusion maps

    International Nuclear Information System (INIS)

    Chinde, V; Vaidya, U; Laflamme, S; Cao, L

    2016-01-01

    In this work, we develop a data-driven method for the diagnosis of damage in mesoscale mechanical structures using an array of distributed sensor networks. The proposed approach relies on comparing intrinsic geometries of data sets corresponding to the undamaged and damaged states of the system. We use a spectral diffusion map approach to identify the intrinsic geometry of the data set. In particular, time series data from distributed sensors is used for the construction of diffusion maps. The low dimensional embedding of the data set corresponding to different damage levels is obtained using a singular value decomposition of the diffusion map. We construct appropriate metrics in the diffusion space to compare the different data sets corresponding to different damage cases. The developed algorithm is applied for damage diagnosis of wind turbine blades. To achieve this goal, we developed a detailed finite element-based model of CX-100 blade in ANSYS using shell elements. Typical damage, such as crack or delamination, will lead to a loss of stiffness, is modeled by altering the stiffness of the laminate layer. One of the main challenges in the development of health monitoring algorithms is the ability to use sensor data with a relatively small signal-to-noise ratio. Our developed diffusion map-based algorithm is shown to be robust to the presence of sensor noise. The proposed diffusion map-based algorithm is advantageous by enabling the comparison of data from numerous sensors of similar or different types of data through data fusion, hereby making it attractive to exploit the distributed nature of sensor arrays. This distributed nature is further exploited for the purpose of damage localization. We perform extensive numerical simulations to demonstrate that the proposed method can successfully determine the extent of damage on the wind turbine blade and also localize the damage. We also present preliminary results for the application of the developed algorithm on

  16. Edge Matters

    DEFF Research Database (Denmark)

    Earon, Ofri

    2013-01-01

    of this container is to separate inside from outside and to protect and provide privacy, psychological as well as physical (Venturi, 1966). But, if dwelling phenomenon takes place both inside and outside the private house – why is the urban house an enclosed box? What is the differentiation between inside...... and outside the contemporary urban house? And what is the interplay between them? The research argues for re-thinking the edge zone between inside and outside the urban house. Therefore, although, residential buildings in the city are the objects of study, the focal point here is the edge zone along...... the building. The research explores and develops the architectural characteristics of correlations between the resident, the singular unit, the building and the given location at the edge zone. It approaches the edge zone of the urban house as a platform for dynamic interactions between these behaviours...

  17. Tremor Detection Using Parametric and Non-Parametric Spectral Estimation Methods: A Comparison with Clinical Assessment

    Science.gov (United States)

    Martinez Manzanera, Octavio; Elting, Jan Willem; van der Hoeven, Johannes H.; Maurits, Natasha M.

    2016-01-01

    In the clinic, tremor is diagnosed during a time-limited process in which patients are observed and the characteristics of tremor are visually assessed. For some tremor disorders, a more detailed analysis of these characteristics is needed. Accelerometry and electromyography can be used to obtain a better insight into tremor. Typically, routine clinical assessment of accelerometry and electromyography data involves visual inspection by clinicians and occasionally computational analysis to obtain objective characteristics of tremor. However, for some tremor disorders these characteristics may be different during daily activity. This variability in presentation between the clinic and daily life makes a differential diagnosis more difficult. A long-term recording of tremor by accelerometry and/or electromyography in the home environment could help to give a better insight into the tremor disorder. However, an evaluation of such recordings using routine clinical standards would take too much time. We evaluated a range of techniques that automatically detect tremor segments in accelerometer data, as accelerometer data is more easily obtained in the home environment than electromyography data. Time can be saved if clinicians only have to evaluate the tremor characteristics of segments that have been automatically detected in longer daily activity recordings. We tested four non-parametric methods and five parametric methods on clinical accelerometer data from 14 patients with different tremor disorders. The consensus between two clinicians regarding the presence or absence of tremor on 3943 segments of accelerometer data was employed as reference. The nine methods were tested against this reference to identify their optimal parameters. Non-parametric methods generally performed better than parametric methods on our dataset when optimal parameters were used. However, one parametric method, employing the high frequency content of the tremor bandwidth under consideration

  18. Data and software tools for gamma radiation spectral threat detection and nuclide identification algorithm development and evaluation

    International Nuclear Information System (INIS)

    Portnoy, David; Fisher, Brian; Phifer, Daniel

    2015-01-01

    The detection of radiological and nuclear threats is extremely important to national security. The federal government is spending significant resources developing new detection systems and attempting to increase the performance of existing ones. The detection of illicit radionuclides that may pose a radiological or nuclear threat is a challenging problem complicated by benign radiation sources (e.g., cat litter and medical treatments), shielding, and large variations in background radiation. Although there is a growing acceptance within the community that concentrating efforts on algorithm development (independent of the specifics of fully assembled systems) has the potential for significant overall system performance gains, there are two major hindrances to advancements in gamma spectral analysis algorithms under the current paradigm: access to data and common performance metrics along with baseline performance measures. Because many of the signatures collected during performance measurement campaigns are classified, dissemination to algorithm developers is extremely limited. This leaves developers no choice but to collect their own data if they are lucky enough to have access to material and sensors. This is often combined with their own definition of metrics for measuring performance. These two conditions make it all but impossible for developers and external reviewers to make meaningful comparisons between algorithms. Without meaningful comparisons, performance advancements become very hard to achieve and (more importantly) recognize. The objective of this work is to overcome these obstacles by developing and freely distributing real and synthetically generated gamma-spectra data sets as well as software tools for performance evaluation with associated performance baselines to national labs, academic institutions, government agencies, and industry. At present, datasets for two tracks, or application domains, have been developed: one that includes temporal

  19. Data and software tools for gamma radiation spectral threat detection and nuclide identification algorithm development and evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Portnoy, David; Fisher, Brian; Phifer, Daniel

    2015-06-01

    The detection of radiological and nuclear threats is extremely important to national security. The federal government is spending significant resources developing new detection systems and attempting to increase the performance of existing ones. The detection of illicit radionuclides that may pose a radiological or nuclear threat is a challenging problem complicated by benign radiation sources (e.g., cat litter and medical treatments), shielding, and large variations in background radiation. Although there is a growing acceptance within the community that concentrating efforts on algorithm development (independent of the specifics of fully assembled systems) has the potential for significant overall system performance gains, there are two major hindrances to advancements in gamma spectral analysis algorithms under the current paradigm: access to data and common performance metrics along with baseline performance measures. Because many of the signatures collected during performance measurement campaigns are classified, dissemination to algorithm developers is extremely limited. This leaves developers no choice but to collect their own data if they are lucky enough to have access to material and sensors. This is often combined with their own definition of metrics for measuring performance. These two conditions make it all but impossible for developers and external reviewers to make meaningful comparisons between algorithms. Without meaningful comparisons, performance advancements become very hard to achieve and (more importantly) recognize. The objective of this work is to overcome these obstacles by developing and freely distributing real and synthetically generated gamma-spectra data sets as well as software tools for performance evaluation with associated performance baselines to national labs, academic institutions, government agencies, and industry. At present, datasets for two tracks, or application domains, have been developed: one that includes temporal

  20. Early detection of nucleate boiling and spectral analysis of acoustical noise

    International Nuclear Information System (INIS)

    Bouneder, M.

    1987-01-01

    The development of a reliable detection technique for the onset of boiling has been further pursued. Besides the already studied tube geometry, a more realistic annular set up has been used where a fuel pin model, electrically heated, is placed. Using accelerometers on the pin, on the structure and on specific instrumentation cables the onset of boiling was clearly monitored by the emergence of a typical resonance frequency. The influence of pressure and heat power was analysed in detail. Furthermore, a glass model has been constructed in order to better correlate the observed measurement with the boiling parameters, as bubble radius, frequency and collapse mode

  1. Bloodstain detection and discrimination impacted by spectral shift when using an interference filter-based visible and near-infrared multispectral crime scene imaging system

    Science.gov (United States)

    Yang, Jie; Messinger, David W.; Dube, Roger R.

    2018-03-01

    Bloodstain detection and discrimination from nonblood substances on various substrates are critical in forensic science as bloodstains are a critical source for confirmatory DNA tests. Conventional bloodstain detection methods often involve time-consuming sample preparation, a chance of harm to investigators, the possibility of destruction of blood samples, and acquisition of too little data at crime scenes either in the field or in the laboratory. An imaging method has the advantages of being nondestructive, noncontact, real-time, and covering a large field-of-view. The abundant spectral information provided by multispectral imaging makes it a potential presumptive bloodstain detection and discrimination method. This article proposes an interference filter (IF) based area scanning three-spectral-band crime scene imaging system used for forensic bloodstain detection and discrimination. The impact of large angle of views on the spectral shift of calibrated IFs is determined, for both detecting and discriminating bloodstains from visually similar substances on multiple substrates. Spectral features in the visible and near-infrared portion employed by the relative band depth method are used. This study shows that 1 ml bloodstain on black felt, gray felt, red felt, white cotton, white polyester, and raw wood can be detected. Bloodstains on the above substrates can be discriminated from cola, coffee, ketchup, orange juice, red wine, and green tea.

  2. Refinements in the use of equivalent latitude for assimilating sporadic inhomogeneous stratospheric tracer observations, 1: Detecting transport of Pinatubo aerosol across a strong vortex edge

    Directory of Open Access Journals (Sweden)

    P. Good

    2004-01-01

    Full Text Available The use of PV equivalent latitude for assimilating stratospheric tracer observations is discussed - with particular regard to the errors in the equivalent latitude coordinate, and to the assimilation of sparse data. Some example measurements are assimilated: they sample the stratosphere sporadically and inhomogeneously. The aim was to obtain precise information about the isentropic tracer distribution and evolution as a function of equivalent latitude. Precision is important, if transport across barriers like the vortex edge are to be detected directly. The main challenges addressed are the errors in modelled equivalent latitude, and the non-ideal observational sampling. The methods presented allow first some assessment of equivalent latitude errors and a picture of how good or poor the observational coverage is. This information determines choices in the approach for estimating as precisely as possible the true equivalent latitude distribution of the tracer, in periods of good and poor observational coverage. This is in practice an optimisation process, since better understanding of the equivalent latitude distribution of the tracer feeds back into a clearer picture of the errors in the modelled equivalent latitude coordinate. Error estimates constrain the reliability of using equivalent latitude to make statements like 'this observation samples air poleward of the vortex edge' or that of more general model-measurement comparisons. The approach is demonstrated for ground-based lidar soundings of the Mount Pinatubo aerosol cloud, focusing on the 1991-92 arctic vortex edge between 475-520K. Equivalent latitude is estimated at the observation times and locations from Eulerian model tracers initialised with PV and forced by UK Meteorological Office analyses. With the model formulation chosen, it is shown that tracer transport of a few days resulted in an error distribution that was much closer to Gaussian form, although the mean error was not

  3. Robust chemical and chemical-resistant material detection using hyper-spectral imager and a new bend interpolation and local scaling HSI sharpening method

    Science.gov (United States)

    Chen, Hai-Wen; McGurr, Michael; Brickhouse, Mark

    2015-05-01

    We present new results from our ongoing research activity for chemical threat detection using hyper-spectral imager (HSI) detection techniques by detecting nontraditional threat spectral signatures of agent usage, such as protective equipment, coatings, paints, spills, and stains that are worn by human or on trucks or other objects. We have applied several current state-of-the-art HSI target detection methods such as Matched Filter (MF), Adaptive Coherence Estimator (ACE), Constrained Energy Minimization (CEM), and Spectral Angle Mapper (SAM). We are interested in detecting several chemical related materials: (a) Tyvek clothing is chemical resistance and Tyvek coveralls are one-piece garments for protecting human body from harmful chemicals, and (b) ammonium salts from background could be representative of spills from scrubbers or related to other chemical activities. The HSI dataset that we used for detection covers a chemical test field with more than 50 different kinds of chemicals, protective materials, coatings, and paints. Among them, there are four different kinds of Tyvek material, three types of ammonium salts, and one yellow jugs. The imagery cube data were collected by a HSI sensor with a spectral range of 400-2,500nm. Preliminary testing results are promising, and very high probability of detection (Pd) and low probability of false detection are achieved with the usage of full spectral range (400- 2,500nm). In the second part of this paper, we present our newly developed HSI sharpening technique. A new Band Interpolation and Local Scaling (BILS) method has been developed to improve HSI spatial resolution by 4-16 times with a low-cost high-resolution pen-chromatic camera and a RGB camera. Preliminary results indicate that this new technique is promising.

  4. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    Energy Technology Data Exchange (ETDEWEB)

    Fallenberg, E.M.; Renz, D.M. [Charite - Universitaetsmedizin Berlin, Clinic of Radiology, Berlin (Germany); Dromain, C. [Institut Gustave Roussy, Department of Radiology, Villejuif cedex (France); Diekmann, F. [St. Joseph-Stift Bremen, Department of Medical Imaging, Bremen (Germany); Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U. [Charite - Universitaetsmedizin Berlin, Department of Radiology, Berlin (Germany); Ingold-Heppner, B. [Charite - Universitaetsmedizin Berlin, Institute of Pathology, Berlin (Germany); Winzer, K.J. [Charite - Universitaetsmedizin Berlin, Breast Center, Department of Gynecology, Berlin (Germany)

    2014-01-15

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  5. Contrast-enhanced spectral mammography versus MRI: Initial results in the detection of breast cancer and assessment of tumour size

    International Nuclear Information System (INIS)

    Fallenberg, E.M.; Renz, D.M.; Dromain, C.; Diekmann, F.; Engelken, F.; Krohn, M.; Singh, J.M.; Bick, U.; Ingold-Heppner, B.; Winzer, K.J.

    2014-01-01

    To compare mammography (MG), contrast-enhanced spectral mammography (CESM), and magnetic resonance imaging (MRI) in the detection and size estimation of histologically proven breast cancers using postoperative histology as the gold standard. After ethical approval, 80 women with newly diagnosed breast cancer underwent MG, CESM, and MRI examinations. CESM was reviewed by an independent experienced radiologist, and the maximum dimension of suspicious lesions was measured. For MG and MRI, routine clinical reports of breast specialists, with judgment based on the BI-RADS lexicon, were used. Results of each imaging technique were correlated to define the index cancer. Fifty-nine cases could be compared to postoperative histology for size estimation. Breast cancer was visible in 66/80 MG, 80/80 CESM, and 77/79 MRI examinations. Average lesion largest dimension was 27.31 mm (SD 22.18) in MG, 31.62 mm (SD 24.41) in CESM, and 27.72 mm (SD 21.51) in MRI versus 32.51 mm (SD 29.03) in postoperative histology. No significant difference was found between lesion size measurement on MRI and CESM compared with histopathology. Our initial results show a better sensitivity of CESM and MRI in breast cancer detection than MG and a good correlation with postoperative histology in size assessment. (orig.)

  6. Diagnostic accuracy of fracture detection in suspected non-accidental injury: the effect of edge enhancement and digital display on observer performance

    Energy Technology Data Exchange (ETDEWEB)

    Offiah, A.C. [Department of Radiology, Great Ormond Street Hospital for Children, London (United Kingdom) and Institute of Child Health, London (United Kingdom)]. E-mail: amaka.offiah@gosh.nhs.uk; Moon, L. [Department of Radiology, Great Ormond Street Hospital for Children, London (United Kingdom); Hall, C.M. [Department of Radiology, Great Ormond Street Hospital for Children, London (United Kingdom); Todd-Pokropek, A. [Department of Medical Physics and Bioengineering, University College London, London (United Kingdom)

    2006-02-15

    AIM: To compare the effect of varying degrees of edge enhancement and method of digital image display on fracture detection in suspected non-accidental injury (NAI). MATERIALS AND METHODS: Fifty radiographs from post-mortem skeletal surveys in 13 children with suspected NAI were selected. Images were obtained using a Fuji 5000R computed radiography system. Hard copies were printed with edge enhancement factors 0, 0.5 and 1.2. Images (edge enhancement 0.5) were also displayed on a 1K{sup 2} monitor. Six observers independently evaluated all 200 images for the presence of abnormality. Observers also scored each image for visualization of soft tissues, visualization of trabecular markings and overall image quality. The paired Student's t-test and location receiver operating curve (ROC) analysis were used to compare quality scores and diagnostic accuracy of each display method. Individual and pooled true-positive rates (sensitivity) were determined. For the purposes of ROC analysis, histology was taken as the gold standard. RESULTS: There was no difference in duration of hard and soft-copy reading sessions (p=0.76). After image manipulation soft-copy radiographs scored significantly better for image quality than hard copy (p<0.0001). Pooled observer sensitivity (at a specificity of 90%) was below 50% for all display methods. Diagnostic accuracy varied significantly between observers. Diagnostic accuracy of individual observers was not affected by display method. CONCLUSION: In suspected NAI, diagnostic accuracy of fracture detection is generally low. Diagnostic accuracy appears to be affected more by observer-related factors than by the method of digital image display.

  7. Performance of horn-coupled transition edge sensors for L- and S-band optical detection on the SAFARI instrument

    Science.gov (United States)

    Goldie, D. J.; Glowacka, D. M.; Withington, S.; Chen, Jiajun; Ade, P. A. R.; Morozov, D.; Sudiwala, R.; Trappe, N. A.; Quaranta, O.

    2016-07-01

    We describe the geometry, architecture, dark- and optical performance of ultra-low-noise transition edge sensors as THz detectors for the SAFARI instrument. The TESs are fabricated from superconducting Mo/Au bilayers coupled to impedance-matched superconducting β-phase Ta thin-film absorbers. The detectors have phonon-limited dark noise equivalent powers of order 0.5 - 1.0 aW/ √ Hz and saturation powers of order 20 - 40 fW. The low temperature test configuration incorporating micro-machined backshorts is also described, and construction and typical performance characteristics for the optical load are shown. We report preliminary measurements of the optical performance of these TESs for two SAFARI bands; L-band at 110 - 210 μm and S-band 34 - 60 μm .

  8. Spectral edge: gradient-preserving spectral mapping for image fusion.

    Science.gov (United States)

    Connah, David; Drew, Mark S; Finlayson, Graham D

    2015-12-01

    This paper describes a novel approach to image fusion for color display. Our goal is to generate an output image whose gradient matches that of the input as closely as possible. We achieve this using a constrained contrast mapping paradigm in the gradient domain, where the structure tensor of a high-dimensional gradient representation is mapped exactly to that of a low-dimensional gradient field which is then reintegrated to form an output. Constraints on output colors are provided by an initial RGB rendering. Initially, we motivate our solution with a simple "ansatz" (educated guess) for projecting higher-D contrast onto color gradients, which we expand to a more rigorous theorem to incorporate color constraints. The solution to these constrained optimizations is closed-form, allowing for simple and hence fast and efficient algorithms. The approach can map any N-D image data to any M-D output and can be used in a variety of applications using the same basic algorithm. In this paper, we focus on the problem of mapping N-D inputs to 3D color outputs. We present results in five applications: hyperspectral remote sensing, fusion of color and near-infrared or clear-filter images, multilighting imaging, dark flash, and color visualization of magnetic resonance imaging diffusion-tensor imaging.

  9. Ocean Classification of Dynamical Structures Detected by SAR and Spectral Methods

    Science.gov (United States)

    Redondo, J. M.; Martinez-Benjamin, J. J.; Tellez, J. D.; Jorge, J.; Diez, M.; Sekula, E.

    2016-08-01

    We discuss a taxonomy of different dynamical features in the ocean surface and provide some eddy and front statistics, as well as describing some events detected by several satellites and even with additional cruise observations and measurements, in the North-west Mediterranean Sea area between 1996 and 2012. The structure of the flows are presented using self-similar traces that may be used to parametrize mixing at both limits of the Rossby Deformation Radius scale, RL. Results show the ability to identify different SAR signatures and at the same time provide calibrations for the different local configurations of vortices, spirals, Langmuir cells, oil spills and tensioactive slicks that eventually allow the study of the self-similar structure of the turbulence. Depending on the surface wind and wave level, and also on the fetch. the bathimetry, the spiral parameters and the resolution of vortical features change. Previous descriptions did not include the new wind and buoyancy features. SAR images also show the turbulence structure of the coastal area and the Regions of Fresh Water Influence (ROFI). It is noteworthy tt such complex coastal field-dependent behavior is strongly influenced by stratification and rotation of the turbulence spectrum is observed only in the range smaller than the local Rossby deformation radius, RL. The measures of diffusivity from buoy or tracer experiments are used to calibrate the behavior of different tracers and pollutants, both natural and man-made in the NW Mediterranean Sea. Thanks to different polarization and intensity levels in ASAR satellite imagery, these can be used to distinguish between natural and man-made sea surface features due to their distinct self-similar and fractal as a function of spill and slick parameters, environmental conditions and history of both oil releases and weather conditions. Eddy diffusivity map derived from SAR measurements of the ocean surface, performing a feature spatial correlation of the

  10. Comparison of Scheimpflug imaging and spectral domain anterior segment optical coherence tomography for detection of narrow anterior chamber angles.

    Science.gov (United States)

    Grewal, D S; Brar, G S; Jain, R; Grewal, S P S

    2011-05-01

    To compare the performance of anterior chamber volume (ACV) and anterior chamber depth (ACD) obtained using Scheimpflug imaging with angle opening distance (AOD500) and trabecular-iris space area (TISA500) obtained using spectral domain anterior segment optical coherence tomography (SD-ASOCT) in detecting narrow angles classified using gonioscopy. In this prospective, cross-sectional observational study, 265 eyes of 265 consecutive patients underwent sequential Scheimpflug imaging, SD-ASOCT imaging, and gonioscopy. Correlations between gonioscopy grading, ACV, ACD, AOD500, and TISA500 were evaluated. Area under receiver operating characteristic curve (AUC), sensitivity, specificity, and likelihood ratios (LRs) were calculated to assess the performance of ACV, ACD, AOD500, and TISA500 in detecting narrow angles (defined as Shaffer grade ≤1 in all quadrants). SD-ASOCT images were obtained at the nasal and temporal quadrants only. Twenty-eight eyes (10.6%) were classified as narrow angles on gonioscopy. ACV correlated with gonioscopy grading (P<0.001) for temporal (r=0.204), superior (r=0.251), nasal (r=0.213), and inferior (r=0.236) quadrants. ACV correlated with TISA500 for nasal (r=0.135, P=0.029) and temporal (P=0.160, P=0.009) quadrants and also with AOD500 for nasal (r=0.498, P<0.001) and temporal (r=0.517, P<0.001) quadrants. For detection of narrow angles, ACV (AUC=0.935; 95% confidence interval (CI) =0.898-0.961) performed similar to ACD (AUC=0.88, P=0.06) and significantly better than AOD500 nasal (AUC=0.761, P=0.001), AOD500 temporal (AUC=0.808, P<0.001), TISA500 nasal (AUC=0.756, P<0.001), and TISA500 temporal (AUC=0.738, P<0.001). Using a cutoff of 113 mm(3), ACV had 90% sensitivity and 88% specificity for detecting narrow angles. Positive and negative LRs for ACV were 8.63 (95% CI=7.4-10.0) and 0.11 (95% CI=0.03-0.4), respectively. ACV measurements using Scheimpflug imaging outperformed AOD500 and TISA500 using SD-ASOCT for detecting narrow angles.

  11. Health State Monitoring of Bladed Machinery with Crack Growth Detection in BFG Power Plant Using an Active Frequency Shift Spectral Correction Method

    Directory of Open Access Journals (Sweden)

    Weifang Sun

    2017-08-01

    Full Text Available Power generation using waste-gas is an effective and green way to reduce the emission of the harmful blast furnace gas (BFG in pig-iron producing industry. Condition monitoring of mechanical structures in the BFG power plant is of vital importance to guarantee their safety and efficient operations. In this paper, we describe the detection of crack growth of bladed machinery in the BFG power plant via vibration measurement combined with an enhanced spectral correction technique. This technique enables high-precision identification of amplitude, frequency, and phase information (the harmonic information belonging to deterministic harmonic components within the vibration signals. Rather than deriving all harmonic information using neighboring spectral bins in the fast Fourier transform spectrum, this proposed active frequency shift spectral correction method makes use of some interpolated Fourier spectral bins and has a better noise-resisting capacity. We demonstrate that the identified harmonic information via the proposed method is of suppressed numerical error when the same level of noises is presented in the vibration signal, even in comparison with a Hanning-window-based correction method. With the proposed method, we investigated vibration signals collected from a centrifugal compressor. Spectral information of harmonic tones, related to the fundamental working frequency of the centrifugal compressor, is corrected. The extracted spectral information indicates the ongoing development of an impeller blade crack that occurred in the centrifugal compressor. This method proves to be a promising alternative to identify blade cracks at early stages.

  12. Health State Monitoring of Bladed Machinery with Crack Growth Detection in BFG Power Plant Using an Active Frequency Shift Spectral Correction Method.

    Science.gov (United States)

    Sun, Weifang; Yao, Bin; He, Yuchao; Chen, Binqiang; Zeng, Nianyin; He, Wangpeng

    2017-08-09

    Power generation using waste-gas is an effective and green way to reduce the emission of the harmful blast furnace gas (BFG) in pig-iron producing industry. Condition monitoring of mechanical structures in the BFG power plant is of vital importance to guarantee their safety and efficient operations. In this paper, we describe the detection of crack growth of bladed machinery in the BFG power plant via vibration measurement combined with an enhanced spectral correction technique. This technique enables high-precision identification of amplitude, frequency, and phase information (the harmonic information) belonging to deterministic harmonic components within the vibration signals. Rather than deriving all harmonic information using neighboring spectral bins in the fast Fourier transform spectrum, this proposed active frequency shift spectral correction method makes use of some interpolated Fourier spectral bins and has a better noise-resisting capacity. We demonstrate that the identified harmonic information via the proposed method is of suppressed numerical error when the same level of noises is presented in the vibration signal, even in comparison with a Hanning-window-based correction method. With the proposed method, we investigated vibration signals collected from a centrifugal compressor. Spectral information of harmonic tones, related to the fundamental working frequency of the centrifugal compressor, is corrected. The extracted spectral information indicates the ongoing development of an impeller blade crack that occurred in the centrifugal compressor. This method proves to be a promising alternative to identify blade cracks at early stages.

  13. Spectrally-efficient 168 Gb/s/λ WDM 64-QAM single-sideband Nyquist-subcarrier modulation with Kramers-Kronig direct-detection receivers \\ud

    OpenAIRE

    Liu, Zhe; Erkılınç , M. Sezer; Shi, Kai; Sillekens, Eric; Galdino, Lidia; Xu, Tianhua; Thomsen, Benn C.; Byvel, Polina; Killey, Robert I.

    2018-01-01

    Due to their simple and cost-effective transceiver architecture, single-polarization and single-photodiode based direct-detection (DD) systems offer advantages for metropolitan area network and data-center interconnect applications. Single-sideband subcarrier modulation (SSB SCM) signaling with direct detection has the potential to achieve high information spectral density (ISD) but its performance can be significantly degraded by signal-signal beat interference (SSBI). The recently proposed ...

  14. A high-transmission liquid-crystal Fabry-Perot infrared filter for electrically tunable spectral imaging detection

    Science.gov (United States)

    Liu, Zhonglun; Xin, Zhaowei; Long, Huabao; Wei, Dong; Dai, Wanwan; Zhang, Xinyu; Wang, Haiwei; Xie, Changsheng

    2018-02-01

    Previous studies have presented the usefulness of typical liquid-crystal Fabry-Perot (LC-FP) infrared filters for spectral imaging detection. Yet, their infrared transmission performances still remain to improve or even rise. In this paper, we propose a new type of electrically tunable LC-FP infrared filter to solve the problem above. The key component of the device is a FP resonant cavity composed of two parallel plane mirrors, in which the zinc selenide (ZnSe) materials with a very high transmittance in the mid-long-wavelength infrared regions are used as the electrode substrates and a layer of nano-aluminum (Al) film, which is directly contacted with liquid-crystal materials, is chosen to make high reflective mirrors as well as the electrodes. Particularly, it should be noted that the directional layer made up of ployimide (PI) used previously is removed. The experiment results indicate that the filter can reduce the absorption of infrared wave remarkably, and thus highlight a road to effectively improve the infrared transmittance ability.

  15. Detecting and monitoring water stress states in maize crops using spectral ratios obtained in the photosynthetic domain

    Science.gov (United States)

    Baranoski, Gladimir V. G.; Van Leeuwen, Spencer R.

    2017-07-01

    The reliable detection and monitoring of changes in the water status of crops composed of plants like maize, a highly adaptable C4 species in large demand for both food and biofuel production, are longstanding remote sensing goals. Existing procedures employed to achieve these goals rely predominantly on the spectral signatures of plant leaves in the infrared domain where the light absorption within the foliar tissues is dominated by water. It has been suggested that such procedures could be implemented using subsurface reflectance to transmittance ratios obtained in the visible (photosynthetic) domain with the assistance of polarization devices. However, the experiments leading to this proposition were performed on detached maize leaves, which were not influenced by the whole (living) plant's adaptation mechanisms to water stress. In this work, we employ predictive simulations of light-leaf interactions in the photosynthetic domain to demonstrate that the living specimens' physiological responses to dehydration stress should be taken into account in this context. Our findings also indicate that a reflectance to transmittance ratio obtained in the photosynthetic domain at a lower angle of incidence without the use of polarization devices may represent a cost-effective alternative for the assessment of water stress states in maize crops.

  16. Automated detection of exudative age-related macular degeneration in spectral domain optical coherence tomography using deep learning.

    Science.gov (United States)

    Treder, Maximilian; Lauermann, Jost Lennart; Eter, Nicole

    2018-02-01

    Our purpose was to use deep learning for the automated detection of age-related macular degeneration (AMD) in spectral domain optical coherence tomography (SD-OCT). A total of 1112 cross-section SD-OCT images of patients with exudative AMD and a healthy control group were used for this study. In the first step, an open-source multi-layer deep convolutional neural network (DCNN), which was pretrained with 1.2 million images from ImageNet, was trained and validated with 1012 cross-section SD-OCT scans (AMD: 701; healthy: 311). During this procedure training accuracy, validation accuracy and cross-entropy were computed. The open-source deep learning framework TensorFlow™ (Google Inc., Mountain View, CA, USA) was used to accelerate the deep learning process. In the last step, a created DCNN classifier, using the information of the above mentioned deep learning process, was tested in detecting 100 untrained cross-section SD-OCT images (AMD: 50; healthy: 50). Therefore, an AMD testing score was computed: 0.98 or higher was presumed for AMD. After an iteration of 500 training steps, the training accuracy and validation accuracies were 100%, and the cross-entropy was 0.005. The average AMD scores were 0.997 ± 0.003 in the AMD testing group and 0.9203 ± 0.085 in the healthy comparison group. The difference between the two groups was highly significant (p deep learning-based approach using TensorFlow™, it is possible to detect AMD in SD-OCT with high sensitivity and specificity. With more image data, an expansion of this classifier for other macular diseases or further details in AMD is possible, suggesting an application for this model as a support in clinical decisions. Another possible future application would involve the individual prediction of the progress and success of therapy for different diseases by automatically detecting hidden image information.

  17. Automatic internal crack detection from a sequence of infrared images with a triple-threshold Canny edge detector

    Science.gov (United States)

    Wang, Gaochao; Tse, Peter W.; Yuan, Maodan

    2018-02-01

    Visual inspection and assessment of the condition of metal structures are essential for safety. Pulse thermography produces visible infrared images, which have been widely applied to detect and characterize defects in structures and materials. When active thermography, a non-destructive testing tool, is applied, the necessity of considerable manual checking can be avoided. However, detecting an internal crack with active thermography remains difficult, since it is usually invisible in the collected sequence of infrared images, which makes the automatic detection of internal cracks even harder. In addition, the detection of an internal crack can be hindered by a complicated inspection environment. With the purpose of putting forward a robust and automatic visual inspection method, a computer vision-based thresholding method is proposed. In this paper, the image signals are a sequence of infrared images collected from the experimental setup with a thermal camera and two flash lamps as stimulus. The contrast of pixels in each frame is enhanced by the Canny operator and then reconstructed by a triple-threshold system. Two features, mean value in the time domain and maximal amplitude in the frequency domain, are extracted from the reconstructed signal to help distinguish the crack pixels from others. Finally, a binary image indicating the location of the internal crack is generated by a K-means clustering method. The proposed procedure has been applied to an iron pipe, which contains two internal cracks and surface abrasion. Some improvements have been made for the computer vision-based automatic crack detection methods. In the future, the proposed method can be applied to realize the automatic detection of internal cracks from many infrared images for the industry.

  18. Enhancing the detection of edges and non-differentiable points in an NMR spectrum using delayed-acquisition

    Science.gov (United States)

    Gong, Zhaoyuan; Walls, Jamie D.

    2018-02-01

    Delayed-acquisition, which is a common technique for improving spectral resolution in Fourier transform based spectroscopies, typically relies upon differences in T2 relaxation rates that are often due to underlying differences in dynamics and/or complexities of the spin systems being studied. After an acquisition delay, the broad signals from fast T2 -relaxing species are more suppressed relative to the sharp signals from slow T2 -relaxing species. In this paper, an alternative source of differential "dephasing" under delayed-acquisition is demonstrated that is based solely upon the mathematical properties of the line shape and is independent of the underlying spin dynamics and/or complexity. Signals associated with frequencies where the line shape either changes sharply and/or is non-differentiable at some finite order dephase at a much slower rate than those signals associated with frequencies where the line shape is smooth. Experiments employing delayed-acquisition to study interfaces in biphasic samples, to measure spatially-dependent longitudinal relaxation, and to highlight sharp features in NMR spectra are presented.

  19. Diurnal Variability in Chlorophyll-a, Carotenoids, CDOM and SO42− Intensity of Offshore Seawater Detected by an Underwater Fluorescence-Raman Spectral System

    Science.gov (United States)

    Chen, Jing; Ye, Wangquan; Guo, Jinjia; Luo, Zhao; Li, Ying

    2016-01-01

    A newly developed integrated fluorescence-Raman spectral system (λex = 532 nm) for detecting Chlorophyll-a (chl-a), Chromophoric Dissolved Organic Matter (CDOM), carotenoids and SO42− in situ was used to successfully investigate the diurnal variability of all above. Simultaneously using the integration of fluorescence spectroscopy and Raman spectroscopy techniques provided comprehensive marine information due to the complementarity between the different excitation mechanisms and different selection rules. The investigation took place in offshore seawater of the Yellow Sea (36°05′40′′ N, 120°31′32′′ E) in October 2014. To detect chl-a, CDOM, carotenoids and SO42−, the fluorescence-Raman spectral system was deployed. It was found that troughs of chl-a and CDOM fluorescence signal intensity were observed during high tides, while the signal intensity showed high values with larger fluctuations during ebb-tide. Chl-a and carotenoids were influenced by solar radiation within a day cycle by different detection techniques, as well as displaying similar and synchronous tendency. CDOM fluorescence cause interference to the measurement of SO42−. To avoid such interference, the backup Raman spectroscopy system with λex = 785 nm was employed to detect SO42− concentration on the following day. The results demonstrated that the fluorescence-Raman spectral system has great potential in detection of chl-a, carotenoids, CDOM and SO42− in the ocean. PMID:27420071

  20. Diurnal Variability in Chlorophyll-a, Carotenoids, CDOM and SO42− Intensity of Offshore Seawater Detected by an Underwater Fluorescence-Raman Spectral System

    Directory of Open Access Journals (Sweden)

    Jing Chen

    2016-07-01

    Full Text Available A newly developed integrated fluorescence-Raman spectral system (λex = 532 nm for detecting Chlorophyll-a (chl-a, Chromophoric Dissolved Organic Matter (CDOM, carotenoids and SO42− in situ was used to successfully investigate the diurnal variability of all above. Simultaneously using the integration of fluorescence spectroscopy and Raman spectroscopy techniques provided comprehensive marine information due to the complementarity between the different excitation mechanisms and different selection rules. The investigation took place in offshore seawater of the Yellow Sea (36°05′40′′ N, 120°31′32′′ E in October 2014. To detect chl-a, CDOM, carotenoids and SO42−, the fluorescence-Raman spectral system was deployed. It was found that troughs of chl-a and CDOM fluorescence signal intensity were observed during high tides, while the signal intensity showed high values with larger fluctuations during ebb-tide. Chl-a and carotenoids were influenced by solar radiation within a day cycle by different detection techniques, as well as displaying similar and synchronous tendency. CDOM fluorescence cause interference to the measurement of SO42−. To avoid such interference, the backup Raman spectroscopy system with λex = 785 nm was employed to detect SO42− concentration on the following day. The results demonstrated that the fluorescence-Raman spectral system has great potential in detection of chl-a, carotenoids, CDOM and SO42− in the ocean.

  1. Diurnal Variability in Chlorophyll-a, Carotenoids, CDOM and SO₄(2-) Intensity of Offshore Seawater Detected by an Underwater Fluorescence-Raman Spectral System.

    Science.gov (United States)

    Chen, Jing; Ye, Wangquan; Guo, Jinjia; Luo, Zhao; Li, Ying

    2016-07-13

    A newly developed integrated fluorescence-Raman spectral system (λex = 532 nm) for detecting Chlorophyll-a (chl-a), Chromophoric Dissolved Organic Matter (CDOM), carotenoids and SO₄(2-) in situ was used to successfully investigate the diurnal variability of all above. Simultaneously using the integration of fluorescence spectroscopy and Raman spectroscopy techniques provided comprehensive marine information due to the complementarity between the different excitation mechanisms and different selection rules. The investigation took place in offshore seawater of the Yellow Sea (36°05'40'' N, 120°31'32'' E) in October 2014. To detect chl-a, CDOM, carotenoids and SO₄(2-), the fluorescence-Raman spectral system was deployed. It was found that troughs of chl-a and CDOM fluorescence signal intensity were observed during high tides, while the signal intensity showed high values with larger fluctuations during ebb-tide. Chl-a and carotenoids were influenced by solar radiation within a day cycle by different detection techniques, as well as displaying similar and synchronous tendency. CDOM fluorescence cause interference to the measurement of SO₄(2-). To avoid such interference, the backup Raman spectroscopy system with λex = 785 nm was employed to detect SO₄(2-) concentration on the following day. The results demonstrated that the fluorescence-Raman spectral system has great potential in detection of chl-a, carotenoids, CDOM and SO₄(2-) in the ocean.

  2. Radiometric Normalization of Temporal Images Combining Automatic Detection of Pseudo-Invariant Features from the Distance and Similarity Spectral Measures, Density Scatterplot Analysis, and Robust Regression

    Directory of Open Access Journals (Sweden)

    Ana Paula Ferreira de Carvalho

    2013-05-01

    Full Text Available Radiometric precision is difficult to maintain in orbital images due to several factors (atmospheric conditions, Earth-sun distance, detector calibration, illumination, and viewing angles. These unwanted effects must be removed for radiometric consistency among temporal images, leaving only land-leaving radiances, for optimum change detection. A variety of relative radiometric correction techniques were developed for the correction or rectification of images, of the same area, through use of reference targets whose reflectance do not change significantly with time, i.e., pseudo-invariant features (PIFs. This paper proposes a new technique for radiometric normalization, which uses three sequential methods for an accurate PIFs selection: spectral measures of temporal data (spectral distance and similarity, density scatter plot analysis (ridge method, and robust regression. The spectral measures used are the spectral angle (Spectral Angle Mapper, SAM, spectral correlation (Spectral Correlation Mapper, SCM, and Euclidean distance. The spectral measures between the spectra at times t1 and t2 and are calculated for each pixel. After classification using threshold values, it is possible to define points with the same spectral behavior, including PIFs. The distance and similarity measures are complementary and can be calculated together. The ridge method uses a density plot generated from images acquired on different dates for the selection of PIFs. In a density plot, the invariant pixels, together, form a high-density ridge, while variant pixels (clouds and land cover changes are spread, having low density, facilitating its exclusion. Finally, the selected PIFs are subjected to a robust regression (M-estimate between pairs of temporal bands for the detection and elimination of outliers, and to obtain the optimal linear equation for a given set of target points. The robust regression is insensitive to outliers, i.e., observation that appears to deviate

  3. Detecting Proxima b’s Atmosphere with JWST Targeting CO{sub 2} at 15 μ m Using a High-pass Spectral Filtering Technique

    Energy Technology Data Exchange (ETDEWEB)

    Snellen, I. A. G.; Van Dishoeck, E. F.; Brandl, B. R.; Van Eylen, V. [Leiden Observatory, Leiden University, Postbus 9513, 2300 RA Leiden (Netherlands); Désert, J.-M.; Waters, L. B. F. M.; Dominik, C.; Birkby, J. L. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, P.O. Box 94249, 1090 GE Amsterdam (Netherlands); Robinson, T. [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Meadows, V. [Astronomy Department, University of Washington (United States); Henning, T.; Bouwman, J. [Max-Planck-Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Lahuis, F.; Min, M. [SRON Netherlands Institute for Space Research, Sorbonnelaan 2, 3584 CA Utrecht (Netherlands); Lovis, C. [Observatoire de Genève, Université de Genève, 51 chemin des Maillettes, 1290 Versoix (Switzerland); Sing, D. [School of Physics, University of Exeter, Exeter (United Kingdom); Anglada-Escudé, G. [School of Physics and Astronomy, Queen Mary University of London, 327 Mile End Road, London E1 4NS (United Kingdom); Brogi, M., E-mail: snellen@strw.leidenuniv.nl [Center for Astrophysics and Space Astronomy, University of Colorado at Boulder, Boulder, CO 80309 (United States)

    2017-08-01

    Exoplanet Proxima b will be an important laboratory for the search for extraterrestrial life for the decades ahead. Here, we discuss the prospects of detecting carbon dioxide at 15 μ m using a spectral filtering technique with the Medium Resolution Spectrograph (MRS) mode of the Mid-Infrared Instrument (MIRI) on the James Webb Space Telescope ( JWST ). At superior conjunction, the planet is expected to show a contrast of up to 100 ppm with respect to the star. At a spectral resolving power of R  = 1790–2640, about 100 spectral CO{sub 2} features are visible within the 13.2–15.8 μ m (3B) band, which can be combined to boost the planet atmospheric signal by a factor of 3–4, depending on the atmospheric temperature structure and CO{sub 2} abundance. If atmospheric conditions are favorable (assuming an Earth-like atmosphere), with this new application to the cross-correlation technique, carbon dioxide can be detected within a few days of JWST observations. However, this can only be achieved if both the instrumental spectral response and the stellar spectrum can be determined to a relative precision of ≤1 × 10{sup −4} between adjacent spectral channels. Absolute flux calibration is not required, and the method is insensitive to the strong broadband variability of the host star. Precise calibration of the spectral features of the host star may only be attainable by obtaining deep observations of the system during inferior conjunction that serve as a reference. The high-pass filter spectroscopic technique with the MIRI MRS can be tested on warm Jupiters, Neptunes, and super-Earths with significantly higher planet/star contrast ratios than the Proxima system.

  4. Towards red-edge positions less sensitive to canopy biophysical parameters for leaf chlorophyll estimation using properties optique spectrales des feuilles (PROSPECT) and scattering by arbitrarily inclined leaves (SAILH) simulated data

    NARCIS (Netherlands)

    Cho, M.A.; Skidmore, A.K.; Atzberger, C.

    2008-01-01

    Several methods for extracting the chlorophyll sensitive red-edge position (REP) from hyperspectral data are reported in literature. This study is a continuation of a recent paper published as 'A new technique for extracting the red edge position from hyperspectral data: the linear extrapolation

  5. Silver nanoparticles deposited on amine-functionalized silica spheres and their amalgamation-based spectral and colorimetric detection of Hg(II) ions

    Energy Technology Data Exchange (ETDEWEB)

    Rameshkumar, Perumal; Manivannan, Shanmugam; Ramaraj, Ramasamy, E-mail: ramarajr@yahoo.com [Madurai Kamaraj University, Centre for Photoelectrochemistry, School of Chemistry (India)

    2013-05-15

    A facile synthetic method to decorate amine-functionalized silica spheres (SiO{sub 2}) by silver nanoparticles (Ag NPs) is reported. The transmission electron microscopic (TEM) images showed that spherical Ag NPs with an average particle size of 14 nm were deposited on 250 nm-sized SiO{sub 2} spheres (SiO{sub 2}/Ag NPs). The spectral and colorimetric detection of Hg(II) ions were carried out using the synthesized SiO{sub 2}/Ag NPs with an experimental detection limit of 5 {mu}M. It was found that the addition of Hg(II) ions (150 {mu}M) into the solution of SiO{sub 2}/Ag NPs completely quenched the SPR band of the Ag NPs due to the formation of anisotropic Ag amalgam crystals (AgHg). The selective detection of Hg(II) ions by SiO{sub 2}/Ag NPs in the presence of other environmentally relevant metal ions was also demonstrated using spectral and colorimetric methods.Graphical abstractAmine-functionalized silica spheres are decorated by in situ formation of silver nanoparticles and their spectral and colorimetric detection of Hg(II) ions is reported.

  6. The edge detection algorithm combining smallest univalue segment assimilating nucleus and quaternion%结合四元数与最小核值相似区的边缘检测

    Institute of Scientific and Technical Information of China (English)

    李姗姗; 陈莉; 张永新; 尹化荣; 袁娅婷

    2017-01-01

    目的 针对传统彩色图像边缘检测方法中未充分利用图像色度信息、颜色模型间非线性转换过程中时间和空间的大量耗费、算法实现复杂等问题,将四元数引入最小核值相似区(SUSAN)算法中,提出一种RGB空间下的结合四元数与最小核值相似区的边缘检测算法.方法 该算法首先对彩色图像进行四元数描述,然后用改进的SUSAN算子进行边缘检测.针对其中单一几何阈值g的限制,以及检测出的边缘较粗等问题,本文采用Otsu算法自适应获取双几何阈值,再对弱边缘点集进行边缘生长,最后根据USAN重心及其对称最长轴来确定边缘局部方向,实现对边缘点的局部非极大值抑制,得到最终细化后的边缘图像.结果 实验选取1幅合成彩色图像及3幅标准图像库图像,与彩色Canny算法、SUSAN算法,及采用单阈值的本文算法进行对比,并采用Pratt品质因数衡量边缘定位精度.本文算法能够检测出亮度相近的不同颜色区域之间的边缘,且提取的边缘比较连续、细致,漏检边缘较少.与公认边缘检测效果较好的彩色Canny算法相比,本文算法的品质因数提高了0.012 0,耗时缩短了2.527 9 s.结论 本文提出了一种结合四元数与最小核值相似区的边缘检测算法,实现了四元数与SUSAN算子的有效融合.实验结果表明,该算法能够提高边缘定位精度,对弱噪声具有较好的抑制能力,适用于对实时性要求不高的低层次彩色图像处理.%Objective Edge detection is one of the most fundamental operations in image processing and scene analysis systems because edges form the outline of an object.Edge detection is the procedure of detecting meaningful discontinuities of the image function and providing an effective means for image segmentation,image fusion,and pattern recognition.Grayimage edge detection has been developed with relative saturation;however,the color image edge detection has not

  7. Physical Mechanism, Spectral Detection, and Potential Mitigation of 3D Cloud Effects on OCO-2 Radiances and Retrievals

    Science.gov (United States)

    Cochrane, S.; Schmidt, S.; Massie, S. T.; Iwabuchi, H.; Chen, H.

    2017-12-01

    Analysis of multiple partially cloudy scenes as observed by OCO-2 in nadir and target mode (published previously and reviewed here) revealed that XCO2 retrievals are systematically biased in presence of scattered clouds. The bias can only partially be removed by applying more stringent filtering, and it depends on the degree of scene inhomogeneity as quantified with collocated MODIS/Aqua imagery. The physical reason behind this effect was so far not well understood because in contrast to cloud-mediated biases in imagery-derived aerosol retrievals, passive gas absorption spectroscopy products do not depend on the absolute radiance level and should therefore be less sensitive to 3D cloud effects and surface albedo variability. However, preliminary evidence from 3D radiative transfer calculations suggested that clouds in the vicinity of an OCO-2 footprint not only offset the reflected radiance spectrum, but introduce a spectrally dependent perturbation that affects absorbing channels disproportionately, and therefore bias the spectroscopy products. To understand the nature of this effect for a variety of scenes, we developed the OCO-2 radiance simulator, which uses the available information on a scene (e.g., MODIS-derived surface albedo, cloud distribution, and other parameters) as the basis for 3D radiative transfer calculations that can predict the radiances observed by OCO-2. We present this new tool and show examples of its utility for a few specific scenes. More importantly, we draw conclusions about the physical mechanism behind this 3D cloud effect on radiances and ultimately OCO-2 retrievals, which involves not only the clouds themselves but also the surface. Harnessed with this understanding, we can now detect cloud vicinity effects in the OCO-2 spectra directly, without actually running the 3D radiance simulator. Potentially, it is even possible to mitigate these effects and thus increase data harvest in regions with ubiquitous cloud cover such as the Amazon

  8. Nonreference Medical Image Edge Map Measure

    Directory of Open Access Journals (Sweden)

    Karen Panetta

    2014-01-01

    Full Text Available Edge detection is a key step in medical image processing. It is widely used to extract features, perform segmentation, and further assist in diagnosis. A poor quality edge map can result in false alarms and misses in cancer detection algorithms. Therefore, it is necessary to have a reliable edge measure to assist in selecting the optimal edge map. Existing reference based edge measures require a ground truth edge map to evaluate the similarity between the generated edge map and the ground truth. However, the ground truth images are not available for medical images. Therefore, a nonreference edge measure is ideal for medical image processing applications. In this paper, a nonreference reconstruction based edge map evaluation (NREM is proposed. The theoretical basis is that a good edge map keeps the structure and details of the original image thus would yield a good reconstructed image. The NREM is based on comparing the similarity between the reconstructed image with the original image using this concept. The edge measure is used for selecting the optimal edge detection algorithm and optimal parameters for the algorithm. Experimental results show that the quantitative evaluations given by the edge measure have good correlations with human visual analysis.

  9. Reduction of airfoil trailing edge noise by trailing edge blowing

    International Nuclear Information System (INIS)

    Gerhard, T; Carolus, T; Erbslöh, S

    2014-01-01

    The paper deals with airfoil trailing edge noise and its reduction by trailing edge blowing. A Somers S834 airfoil section which originally was designed for small wind turbines is investigated. To mimic realistic Reynolds numbers the boundary layer is tripped on pressure and suction side. The chordwise position of the blowing slot is varied. The acoustic sources, i.e. the unsteady flow quantities in the turbulent boundary layer in the vicinity of the trailing edge, are quantified for the airfoil without and with trailing edge blowing by means of a large eddy simulation and complementary measurements. Eventually the far field airfoil noise is measured by a two-microphone filtering and correlation and a 40 microphone array technique. Both, LES-prediction and measurements showed that a suitable blowing jet on the airfoil suction side is able to reduce significantly the turbulence intensity and the induced surface pressure fluctuations in the trailing edge region. As a consequence, trailing edge noise associated with a spectral hump around 500 Hz could be reduced by 3 dB. For that a jet velocity of 50% of the free field velocity was sufficient. The most favourable slot position was at 90% chord length

  10. Living edge

    DEFF Research Database (Denmark)

    Earon, Ofri

    2014-01-01

    was originally introduced to enhance indoor qualities including light and view. Throughout the paper, it is argued that these ecological motives have grown to architectural and urban dimensions. The paper analyzes the characteristics and potentials of these dimensions and their interconnections. The paper...... on the ground level, but there is a lack of recognition in the significance of communicative characters as well at the higher part of the edge. The city’s planning approach is “Consider urban life before urban space. Consider urban space before buildings” This urban strategy neglects the possible architectural...... contribution to the street atmosphere and its effect on urban life. Bay balcony has been a common architectural element in Copenhagen’s residential buildings, since the end of the twenties. It is a domestic border with an architectural thickness combining window, door, windowsill and balcony. The bay balcony...

  11. Implications of sensor design for coral reef detection: Upscaling ground hyperspectral imagery in spatial and spectral scales

    Science.gov (United States)

    Caras, Tamir; Hedley, John; Karnieli, Arnon

    2017-12-01

    Remote sensing offers a potential tool for large scale environmental surveying and monitoring. However, remote observations of coral reefs are difficult especially due to the spatial and spectral complexity of the target compared to sensor specifications as well as the environmental implications of the water medium above. The development of sensors is driven by technological advances and the desired products. Currently, spaceborne systems are technologically limited to a choice between high spectral resolution and high spatial resolution, but not both. The current study explores the dilemma of whether future sensor design for marine monitoring should prioritise on improving their spatial or spectral resolution. To address this question, a spatially and spectrally resampled ground-level hyperspectral image was used to test two classification elements: (1) how the tradeoff between spatial and spectral resolutions affects classification; and (2) how a noise reduction by majority filter might improve classification accuracy. The studied reef, in the Gulf of Aqaba (Eilat), Israel, is heterogeneous and complex so the local substrate patches are generally finer than currently available imagery. Therefore, the tested spatial resolution was broadly divided into four scale categories from five millimeters to one meter. Spectral resolution resampling aimed to mimic currently available and forthcoming spaceborne sensors such as (1) Environmental Mapping and Analysis Program (EnMAP) that is characterized by 25 bands of 6.5 nm width; (2) VENμS with 12 narrow bands; and (3) the WorldView series with broadband multispectral resolution. Results suggest that spatial resolution should generally be prioritized for coral reef classification because the finer spatial scale tested (pixel size mind, while the focus in this study was on the technologically limited spaceborne design, aerial sensors may presently provide an opportunity to implement the suggested setup.

  12. Spectral states evolution of 4U 1728-34 observed by INTEGRAL and RXTE: non-thermal component detection

    NARCIS (Netherlands)

    Tarana, A.; Belloni, T.; Bazzano, A.; Mendez, M.; Ubertini, P.

    We report results of a one-year monitoring of the low-mass X-ray binary (LMXB) source (atoll type) 4U 1728-34 with INTEGRAL and RXTE. Three time intervals were covered by INTEGRAL, during which the source showed strong spectral evolution. We studied the broad-band X-ray spectra in detail by fitting

  13. Detection and classification of salmonella serotypes using spectral signatures collected by fourier transform infrared (FT-IR) spectroscopy

    Science.gov (United States)

    Spectral signatures of Salmonella serotypes namely Salmonella Typhimurium, Salmonella Enteritidis, Salmonella Infantis, Salmonella Heidelberg and Salmonella Kentucky were collected using Fourier transform infrared spectroscopy (FT-IR). About 5-10 µL of Salmonella suspensions with concentrations of 1...

  14. Can the same edge-detection algorithm be applied to on-line and off-line analysis systems? Validation of a new cinefilm-based geometric coronary measurement software

    NARCIS (Netherlands)

    J. Haase (Jürgen); C. di Mario (Carlo); P.W.J.C. Serruys (Patrick); M.M.J.M. van der Linden (Mark); D.P. Foley (David); W.J. van der Giessen (Wim)

    1993-01-01

    textabstractIn the Cardiovascular Measurement System (CMS) the edge-detection algorithm, which was primarily designed for the Philips digital cardiac imaging system (DCI), is applied to cinefilms. Comparative validation of CMS and DCI was performed in vitro and in vivo with intracoronary insertion

  15. Analysis of In-Situ Spectral Reflectance of Sago and Other Palms: Implications for Their Detection in Optical Satellite Images

    Science.gov (United States)

    Rendon Santillan, Jojene; Makinano-Santillan, Meriam

    2018-04-01

    We present a characterization, comparison and analysis of in-situ spectral reflectance of Sago and other palms (coconut, oil palm and nipa) to ascertain on which part of the electromagnetic spectrum these palms are distinguishable from each other. The analysis also aims to reveal information that will assist in selecting which band to use when mapping Sago palms using the images acquired by these sensors. The datasets used in the analysis consisted of averaged spectral reflectance curves of each palm species measured within the 345-1045 nm wavelength range using an Ocean Optics USB4000-VIS-NIR Miniature Fiber Optic Spectrometer. This in-situ reflectance data was also resampled to match the spectral response of the 4 bands of ALOS AVNIR-2, 3 bands of ASTER VNIR, 4 bands of Landsat 7 ETM+, 5 bands of Landsat 8, and 8 bands of Worldview-2 (WV2). Examination of the spectral reflectance curves showed that the near infra-red region, specifically at 770, 800 and 875 nm, provides the best wavelengths where Sago palms can be distinguished from other palms. The resampling of the in-situ reflectance spectra to match the spectral response of optical sensors made possible the analysis of the differences in reflectance values of Sago and other palms in different bands of the sensors. Overall, the knowledge learned from the analysis can be useful in the actual analysis of optical satellite images, specifically in determining which band to include or to exclude, or whether to use all bands of a sensor in discriminating and mapping Sago palms.

  16. ANALYSIS OF IN-SITU SPECTRAL REFLECTANCE OF SAGO AND OTHER PALMS: IMPLICATIONS FOR THEIR DETECTION IN OPTICAL SATELLITE IMAGES

    Directory of Open Access Journals (Sweden)

    J. R. Santillan

    2018-04-01

    Full Text Available We present a characterization, comparison and analysis of in-situ spectral reflectance of Sago and other palms (coconut, oil palm and nipa to ascertain on which part of the electromagnetic spectrum these palms are distinguishable from each other. The analysis also aims to reveal information that will assist in selecting which band to use when mapping Sago palms using the images acquired by these sensors. The datasets used in the analysis consisted of averaged spectral reflectance curves of each palm species measured within the 345–1045 nm wavelength range using an Ocean Optics USB4000-VIS-NIR Miniature Fiber Optic Spectrometer. This in-situ reflectance data was also resampled to match the spectral response of the 4 bands of ALOS AVNIR-2, 3 bands of ASTER VNIR, 4 bands of Landsat 7 ETM+, 5 bands of Landsat 8, and 8 bands of Worldview-2 (WV2. Examination of the spectral reflectance curves showed that the near infra-red region, specifically at 770, 800 and 875 nm, provides the best wavelengths where Sago palms can be distinguished from other palms. The resampling of the in-situ reflectance spectra to match the spectral response of optical sensors made possible the analysis of the differences in reflectance values of Sago and other palms in different bands of the sensors. Overall, the knowledge learned from the analysis can be useful in the actual analysis of optical satellite images, specifically in determining which band to include or to exclude, or whether to use all bands of a sensor in discriminating and mapping Sago palms.

  17. Feature Extraction Without Edge Detection

    Science.gov (United States)

    1993-09-01

    Faugeras & Maybank [24], Weng, Ahuja, & Huang[79]). Consequently, many authors assume that it is solved in their analysis (for example, Broida & Chellappa...D. Faugeras and S. Maybank . Motion from point matches: multiplicity of solutions. International Journal of Computer Vision, 4(3):225-246, June 1990

  18. Four novel alkyl 2-cyanoacylate monomers and their use in latent fingermark detection by mid-infrared spectral imaging.

    Science.gov (United States)

    Tahtouh, Mark; Scott, Sonia A; Kalman, John R; Reedy, Brian J

    2011-04-15

    Four novel alkyl 2-cyanoacrylate monomers (alkyl=1-cyanoethyl, 2-cyanoethyl, trideuteromethyl and pentadeuteroethyl) have been tested for their ability to develop latent fingermarks that can then be visualized using mid-infrared spectral (chemical) imaging. Each of the four monomers was chosen for its potential to produce a strong, isolated infrared spectral band in its corresponding polymer (to provide spectral contrast against most backgrounds), as well as for its potential ability to be fumed onto fingermarks in the manner of conventional ethyl 2-cyanoacrylate (superglue). With the exception of the 2-cyanoethyl 2-cyanoacrylate, which had to be fumed under reduced pressure, all of the monomers were found to be sufficiently volatile to be fumed in a conventional fuming cabinet. All four monomers polymerized selectively on fingermark ridges on a variety of non-porous and semi-porous surfaces, leading to excellent development of the fingermarks. Unfortunately, although high quality mid-infrared spectral images of the fingermarks could be formed for all of the polymers at various frequencies, the new CN or CD stretching vibrations did not give rise to strong enough absorption intensities for good contrast on difficult backgrounds such as polymer banknotes. However, in the 1-cyanoethyl 2-cyanoacrylate polymer, the presence of the additional nitrile group had the unintended but desirable effect of shifting the strong CO absorption to higher frequencies, moving it away from interfering banknote absorptions. This enabled fingermark contrast to be achieved even against the intaglio printing on the banknotes. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  19. SCPS: a fast implementation of a spectral method for detecting protein families on a genome-wide scale

    Directory of Open Access Journals (Sweden)

    Paccanaro Alberto

    2010-03-01

    Full Text Available Abstract Background An important problem in genomics is the automatic inference of groups of homologous proteins from pairwise sequence similarities. Several approaches have been proposed for this task which are "local" in the sense that they assign a protein to a cluster based only on the distances between that protein and the other proteins in the set. It was shown recently that global methods such as spectral clustering have better performance on a wide variety of datasets. However, currently available implementations of spectral clustering methods mostly consist of a few loosely coupled Matlab scripts that assume a fair amount of familiarity with Matlab programming and hence they are inaccessible for large parts of the research community. Results SCPS (Spectral Clustering of Protein Sequences is an efficient and user-friendly implementation of a spectral method for inferring protein families. The method uses only pairwise sequence similarities, and is therefore practical when only sequence information is available. SCPS was tested on difficult sets of proteins whose relationships were extracted from the SCOP database, and its results were extensively compared with those obtained using other popular protein clustering algorithms such as TribeMCL, hierarchical clustering and connected component analysis. We show that SCPS is able to identify many of the family/superfamily relationships correctly and that the quality of the obtained clusters as indicated by their F-scores is consistently better than all the other methods we compared it with. We also demonstrate the scalability of SCPS by clustering the entire SCOP database (14,183 sequences and the complete genome of the yeast Saccharomyces cerevisiae (6,690 sequences. Conclusions Besides the spectral method, SCPS also implements connected component analysis and hierarchical clustering, it integrates TribeMCL, it provides different cluster quality tools, it can extract human-readable protein

  20. SCPS: a fast implementation of a spectral method for detecting protein families on a genome-wide scale.

    Science.gov (United States)

    Nepusz, Tamás; Sasidharan, Rajkumar; Paccanaro, Alberto

    2010-03-09

    An important problem in genomics is the automatic inference of groups of homologous proteins from pairwise sequence similarities. Several approaches have been proposed for this task which are "local" in the sense that they assign a protein to a cluster based only on the distances between that protein and the other proteins in the set. It was shown recently that global methods such as spectral clustering have better performance on a wide variety of datasets. However, currently available implementations of spectral clustering methods mostly consist of a few loosely coupled Matlab scripts that assume a fair amount of familiarity with Matlab programming and hence they are inaccessible for large parts of the research community. SCPS (Spectral Clustering of Protein Sequences) is an efficient and user-friendly implementation of a spectral method for inferring protein families. The method uses only pairwise sequence similarities, and is therefore practical when only sequence information is available. SCPS was tested on difficult sets of proteins whose relationships were extracted from the SCOP database, and its results were extensively compared with those obtained using other popular protein clustering algorithms such as TribeMCL, hierarchical clustering and connected component analysis. We show that SCPS is able to identify many of the family/superfamily relationships correctly and that the quality of the obtained clusters as indicated by their F-scores is consistently better than all the other methods we compared it with. We also demonstrate the scalability of SCPS by clustering the entire SCOP database (14,183 sequences) and the complete genome of the yeast Saccharomyces cerevisiae (6,690 sequences). Besides the spectral method, SCPS also implements connected component analysis and hierarchical clustering, it integrates TribeMCL, it provides different cluster quality tools, it can extract human-readable protein descriptions using GI numbers from NCBI, it interfaces with

  1. The gravitational wave background from massive black hole binaries in Illustris: spectral features and time to detection with pulsar timing arrays

    Science.gov (United States)

    Kelley, Luke Zoltan; Blecha, Laura; Hernquist, Lars; Sesana, Alberto; Taylor, Stephen R.

    2017-11-01

    Pulsar timing arrays (PTAs) around the world are using the incredible consistency of millisecond pulsars to measure low-frequency gravitational waves from (super)massive black hole (MBH) binaries. We use comprehensive MBH merger models based on cosmological hydrodynamic simulations to predict the spectrum of the stochastic gravitational wave background (GWB). We use real time-of-arrival specifications from the European, NANOGrav, Parkes, and International PTA (IPTA) to calculate realistic times to detection of the GWB across a wide range of model parameters. In addition to exploring the parameter space of environmental hardening processes (in particular: stellar scattering efficiencies), we have expanded our models to include eccentric binary evolution which can have a strong effect on the GWB spectrum. Our models show that strong stellar scattering and high characteristic eccentricities enhance the GWB strain amplitude near the PTA-sensitive `sweet-spot' (near the frequency f = 1 yr-1), slightly improving detection prospects in these cases. While the GWB amplitude is degenerate between cosmological and environmental parameters, the location of a spectral turnover at low frequencies (f ≲ 0.1 yr-1) is strongly indicative of environmental coupling. At high frequencies (f ≳ 1 yr-1), the GWB spectral index can be used to infer the number density of sources and possibly their eccentricity distribution. Even with merger models that use pessimistic environmental and eccentricity parameters, if the current rate of PTA expansion continues, we find that the IPTA is highly likely to make a detection within about 10 yr.

  2. Image Edge Tracking via Ant Colony Optimization

    Science.gov (United States)

    Li, Ruowei; Wu, Hongkun; Liu, Shilong; Rahman, M. A.; Liu, Sanchi; Kwok, Ngai Ming

    2018-04-01

    A good edge plot should use continuous thin lines to describe the complete contour of the captured object. However, the detection of weak edges is a challenging task because of the associated low pixel intensities. Ant Colony Optimization (ACO) has been employed by many researchers to address this problem. The algorithm is a meta-heuristic method developed by mimicking the natural behaviour of ants. It uses iterative searches to find the optimal solution that cannot be found via traditional optimization approaches. In this work, ACO is employed to track and repair broken edges obtained via conventional Sobel edge detector to produced a result with more connected edges.

  3. CHANGE DETECTION OF CROPPING PATTERN IN PADDY FIELD USING MULTI SPECTRAL SATELLITE DATA FOR ESTIMATING IRRIGATION WATER NEEDS

    Directory of Open Access Journals (Sweden)

    Rizatus Shofiyati1

    2012-10-01

    Full Text Available This paper investigates the use of multi spectral satellite data for cropping pattern monitoring in paddy field. The southern coastal of Citarum watershed, West Java Province was selected as study sites. The analysis used in this study is identifying crop pattern based on growth stages of wetland paddy and other crops by investi-gating the characteristic of Normalized Differen-ce Vegetation Indices (NDVI and Wetness of Tasseled Cap Transformation (TCT derived from 14 scenes of Landsat TM date 1988 to 2001. In general, the phenological of growth stages of wetland paddy can be used to distinguish with other seasonal crops. The research results indicate that multi spectral satellite data has a great potential for identi-fication and monitoring cropping pattern in paddy field. Specific character of NDVI and Wetness can also produce a map of cropping pattern in paddy field that is useful to monitor agricultural land condition. The cropping pattern can also be used to estimate irrigation water needed of paddy field in the area. Expected implication of the information obtained from this analysis is useful for guiding more appropriate planning and better agricultural management.

  4. DAVs: Red Edge and Outbursts

    Science.gov (United States)

    Luan, Jing

    2018-04-01

    As established by ground based surveys, white dwarfs with hydrogen atmospheres pulsate as they cool across the temperature range, 12500Kred edge is a two-decade old puzzle. Recently, Kepler discovered a number of cool DAVs exhibiting sporadic outbursts separated by days, each lasting several hours, and releasing \\sim 10^{33}-10^{34} {erg}. We provide quantitative explanations for both the red edge and the outbursts. The minimal frequency for overstable modes rises abruptly near the red edge. Although high frequency overstable modes exist below the red edge, their photometric amplitudes are generally too small to be detected by ground based observations. Nevertheless, these overstable parent modes can manifest themselves through nonlinear mode couplings to damped daughter modes which generate limit cycles giving rise to photometric outbursts.

  5. Development of on-line sorting system for detection of infected seed potatoes using visible near-infrared transmittance spectral technique

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dae Yong; Cho, Byoung Kwan [Dept. of Biosystems Engineering, Chungnam National University, Daejeon (Korea, Republic of); Mo, Chang Yeun [Rural Development Administration, National Institute of Agricultural Engineering, Jeonju (Korea, Republic of); Kang, Jun Soon [Dept. of Horticultural Bioscience, Pusan National University, Pusan (Korea, Republic of)

    2015-02-15

    In this study, an online seed potato sorting system using a visible and near infrared (40 1100 nm) transmittance spectral technique and statistical model was evaluated for the nondestructive determination of infected and sound seed potatoes. Seed potatoes that had been artificially infected with Pectobacterium atrosepticum, which is known to cause a soil borne disease infection, were prepared for the experiments. After acquiring transmittance spectra from sound and infected seed potatoes, a determination algorithm for detecting infected seed potatoes was developed using the partial least square discriminant analysis method. The coefficient of determination(R{sup 2}{sub p}) of the prediction model was 0.943, and the classification accuracy was above 99% (n = 80) for discriminating diseased seed potatoes from sound ones. This online sorting system has good potential for developing a technique to detect agricultural products that are infected and contaminated by pathogens.

  6. Remote detection of fluid-related diagenetic mineralogical variations in the Wingate Sandstone at different spatial and spectral resolutions

    Science.gov (United States)

    Okyay, Unal; Khan, Shuhab D.

    2016-02-01

    Well-exposed eolian units of the Jurassic system on the Colorado Plateau including the Wingate Sandstone, show prominent color variations throughout southeastern Utah due to diagenetic changes that include precipitation and/or removal of iron oxide, clay, and carbonate cement. Spatially variable characteristic diagenetic changes suggest fluid-rock interactions through the sandstone. Distinctive spectral signatures of diagenetic minerals can be used to map diagenetic mineral variability and possibly fluid-flow pathways. The main objective of this work was to identify characteristic diagenetic minerals, and map their spatial variability from regional to outcrop scale in Wingate Sandstone exposures of Lisbon Valley, Utah. Laboratory reflectance spectroscopy analysis of the samples facilitated identification of diagnostic spectral characteristics of the common diagenetic minerals and their relative abundances between altered and unaltered Wingate Sandstone. Comparison of reflectance spectroscopy with satellite, airborne, and ground-based imaging spectroscopy data provided a method for mapping and evaluating spatial variations of diagenetic minerals. The Feature-oriented Principal Component Selection method was used on Advanced Spaceborne Thermal Emission and Reflection Radiometer data so as to map common mineral groups throughout the broader Wingate Sandstone exposure in the area. The Minimum Noise Fraction and Spectral Angle Mapper methods were applied on airborne HyMap and ground-based hyperspectral imaging data to identify and map mineralogical changes. The satellite and airborne data showed that out of 25.55 km2 total exposure of Wingate Sandstone in Lisbon Valley, unaltered sandstone cover 12.55 km2, and altered sandstone cover 8.90 km2 in the northwest flank and 5.09 km2 in the southern flank of the anticline. The ground-based hyperspectral data demonstrated the ability to identify and map mineral assemblages with two-dimensional lateral continuity on near

  7. Fourier transform infrared spectral detection of life in polar subsurface environments and its application to Mars exploration.

    Science.gov (United States)

    Preston, Louisa J; Johnson, Diane; Cockell, Charles S; Grady, Monica M

    2015-09-01

    Cryptoendolithic lichen communities of the Dry Valleys, Antarctica, survive in an extremely inhospitable environment, finding refuge in microscopic niches where conditions suitable for life exist. Such "within-rock" communities may have evolved on Mars when conditions for life on the surface deteriorated to such an extent that they could no longer survive. Fourier transform infrared spectroscopy of unprepared whole-rock Antarctic Beacon sandstones was used to vertically profile molecular vibrations of fatty acids, proteins, and carboxylic acids created by endolithic communities. Spectral biosignatures were found localized to lichen-rich areas and were absent in crustal regions and the bulk rock substrate. These cryptoendolithic profiles will aid similar spectroscopic investigations of organic biosignatures during future Martian subsurface studies and will help in the identification of similar communities in other localities across the Earth.

  8. Detection of wine grape nutrient levels using visible and near infrared 1nm spectral resolution remote sensing

    Science.gov (United States)

    Anderson, Grant; van Aardt, Jan; Bajorski, Peter; Vanden Heuvel, Justine

    2016-05-01

    The grape industry relies on regular crop assessment to aid in the day-to-day and seasonal management of their crop. More specifically, there are six key nutrients of interest to viticulturists in the growing of wine grapes, namely nitrogen, potassium, phosphorous, magnesium, zinc and boron. Traditional methods of determining the levels of these nutrients are through collection and chemical analysis of petiole samples from the grape vines themselves. We collected ground-level observations of the spectra of the grape vines, using a hyperspectral spectrometer (0.4-2.5um), at the same time that petioles samples were harvested. We then interpolated the data into a consistent 1 nm spectral resolution before comparing it to the nutrient data collected. This nutrient data came from both the industry standard petiole analysis, as well as an additional leaf-level analysis. The data were collected for two different grape cultivars, both during bloom and veraison periods to provide variability, while also considering the impact of temporal/seasonal change. A narrow-band NDI (Normalized Difference Index) approach, as well as a simple ratio index, was used to determine the correlation of the reflectance data to the nutrient data. This analysis was limited to the silicon photodiode range to increase the utility of our approach for wavelength-specific cameras (via spectral filters) in a low cost drone platform. The NDI generated correlation coefficients were as high as 0.80 and 0.88 for bloom and veraison, respectively. The ratio index produced correlation coefficient results that are the same at two decimal places with 0.80 and 0.88. These results bode well for eventual non-destructive, accurate and precise assessment of vineyard nutrient status.

  9. Comparative Investigation of Guided Fuzzy Clustering and Mean Shift Clustering for Edge Detection in Electrical Resistivity Tomography Images of Mineral Deposits

    Science.gov (United States)

    Ward, Wil; Wilkinson, Paul; Chambers, Jon; Bai, Li

    2014-05-01

    Geophysical surveying using electrical resistivity tomography (ERT) can be used as a rapid non-intrusive method to investigate mineral deposits [1]. One of the key challenges with this approach is to find a robust automated method to assess and characterise deposits on the basis of an ERT image. Recent research applying edge detection techniques has yielded a framework that can successfully locate geological interfaces in ERT images using a minimal assumption data clustering technique, the guided fuzzy clustering method (gfcm) [2]. Non-parametric clustering techniques are statistically grounded methods of image segmentation that do not require any assumptions about the distribution of data under investigation. This study is a comparison of two such methods to assess geological structure based on the resistivity images. In addition to gfcm, a method called mean-shift clustering [3] is investigated with comparisons directed at accuracy, computational expense, and degree of user interaction. Neither approach requires the number of clusters as input (a common parameter and often impractical), rather they are based on a similar theory that data can be clustered based on peaks in the probability density function (pdf) of the data. Each local maximum in these functions represents the modal value of a particular population corresponding to a cluster and as such the data are assigned based on their relationships to these model values. The two methods differ in that gfcm approximates the pdf using kernel density estimation and identifies population means, assigning cluster membership probabilities to each resistivity value in the model based on its distance from the distribution averages. Whereas, in mean-shift clustering, the density function is not calculated, but a gradient ascent method creates a vector that leads each datum towards high density distributions iteratively using weighted kernels to calculate locally dense regions. The only parameter needed in both methods

  10. Novel ST-MUSIC-based spectral analysis for detection of ULF geomagnetic signals anomalies associated with seismic events in Mexico

    Directory of Open Access Journals (Sweden)

    Omar Chavez

    2016-05-01

    Full Text Available Recently, the analysis of ultra-low-frequency (ULF geomagnetic signals in order to detect seismic anomalies has been reported in several works. Yet, they, although having promising results, present problems for their detection since these anomalies are generally too much weak and embedded in high noise levels. In this work, a short-time multiple signal classification (ST-MUSIC, which is a technique with high-frequency resolution and noise immunity, is proposed for the detection of seismic anomalies in the ULF geomagnetic signals. Besides, the energy (E of geomagnetic signals processed by ST-MUSIC is also presented as a complementary parameter to measure the fluctuations between seismic activity and seismic calm period. The usefulness and effectiveness of the proposal are demonstrated through the analysis of a synthetic signal and five real signals with earthquakes. The analysed ULF geomagnetic signals have been obtained using a tri-axial fluxgate magnetometer at the Juriquilla station, which is localized in Queretaro, Mexico (geographic coordinates: longitude 100.45° E and latitude 20.70° N. The results obtained show the detection of seismic perturbations before, during, and after the main shock, making the proposal a suitable tool for detecting seismic precursors.

  11. Non-invasive detection of the freezing of gait in Parkinson's disease using spectral and wavelet features.

    Science.gov (United States)

    Nazarzadeh, Kimia; Arjunan, Sridhar P; Kumar, Dinesh K; Das, Debi Prasad

    2016-08-01

    In this study, we have analyzed the accelerometer data recorded during gait analysis of Parkinson disease patients for detecting freezing of gait (FOG) episodes. The proposed method filters the recordings for noise reduction of the leg movement changes and computes the wavelet coefficients to detect FOG events. Publicly available FOG database was used and the technique was evaluated using receiver operating characteristic (ROC) analysis. Results show a higher performance of the wavelet feature in discrimination of the FOG events from the background activity when compared with the existing technique.

  12. Estimation of Signal Coherence Threshold and Concealed Spectral Lines Applied to Detection of Turbofan Engine Combustion Noise

    Science.gov (United States)

    Miles, Jeffrey Hilton

    2010-01-01

    Combustion noise from turbofan engines has become important, as the noise from sources like the fan and jet are reduced. An aligned and un-aligned coherence technique has been developed to determine a threshold level for the coherence and thereby help to separate the coherent combustion noise source from other noise sources measured with far-field microphones. This method is compared with a statistics based coherence threshold estimation method. In addition, the un-aligned coherence procedure at the same time also reveals periodicities, spectral lines, and undamped sinusoids hidden by broadband turbofan engine noise. In calculating the coherence threshold using a statistical method, one may use either the number of independent records or a larger number corresponding to the number of overlapped records used to create the average. Using data from a turbofan engine and a simulation this paper shows that applying the Fisher z-transform to the un-aligned coherence can aid in making the proper selection of samples and produce a reasonable statistics based coherence threshold. Examples are presented showing that the underlying tonal and coherent broad band structure which is buried under random broadband noise and jet noise can be determined. The method also shows the possible presence of indirect combustion noise. Copyright 2011 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.

  13. Monochromatic Spectral Computed Tomography with Low Iodine Concentration Contrast Medium in a Rabbit VX2 Liver Model:: Investigation of Image Quality and Detection Rate.

    Science.gov (United States)

    Zhou, Yue; Xu, Han; Hou, Ping; Dong, Jun Q; Wang, Ming Y; Gao, Jian B

    2016-04-01

    This study aimed to validate the feasibility of using virtual monochromatic spectral computed tomography (CT) with isotonic low iodine concentration contrast medium for VX2 hepatic tumors. Sixty New Zealand white rabbits with implanted VX2 hepatic tumors underwent two-phase contrast-enhanced spectral CT imaging on the 14th day after tumor implantation. They were randomly divided into groups A, B, and C, with 20 rabbits each (group A: 270 mg I/mL, monochromatic spectral images; group B: 370 mg I/mL, conventional 120 kVp images, 100% filtered back projection [FBP]; group C: 270 mg I/mL, conventional 120 kVp images, 100% FBP). Group A was further divided into two subgroups (subgroup A1: 100% FBP; subgroup A2: 50% FBP + 50% adaptive statistical iterative reconstruction). Objective evaluation (signal-to-noise ratio [SNR], contrast-to-noise ratio [CNR], and image noise), subjective rating score (image noise score, anatomical details score, overall image quality score, and lesion conspicuity score), CT dose index volume, and dose length product were compared between groups during two-phase contrast enhancement. The detection rates of the four groups were calculated as percentages. Image noise (SNR and CNR) among the four groups was statistically significant (P noise in group A2 was lower than in group A1, but higher than that in groups B and C (P noise score of group A2 was higher than that of the other three groups. In terms of the anatomic details score, the overall image quality score, and the lesion conspicuity score, the images of group A2 were superior to that of groups A1 and C. For hepatic tumor diameters more than or equal to 1.0 cm and less than 3.0 cm, group A achieved a higher detection rate than groups B and C. The CT dose index volume, dose length product, and effective dose in group A were significantly lower than that in groups B and C (P noise, increase detection rate for small tumors, and decrease radiation dose and iodine load in

  14. Estimation of spectral kurtosis

    Science.gov (United States)

    Sutawanir

    2017-03-01

    Rolling bearings are the most important elements in rotating machinery. Bearing frequently fall out of service for various reasons: heavy loads, unsuitable lubrications, ineffective sealing. Bearing faults may cause a decrease in performance. Analysis of bearing vibration signals has attracted attention in the field of monitoring and fault diagnosis. Bearing vibration signals give rich information for early detection of bearing failures. Spectral kurtosis, SK, is a parameter in frequency domain indicating how the impulsiveness of a signal varies with frequency. Faults in rolling bearings give rise to a series of short impulse responses as the rolling elements strike faults, SK potentially useful for determining frequency bands dominated by bearing fault signals. SK can provide a measure of the distance of the analyzed bearings from a healthy one. SK provides additional information given by the power spectral density (psd). This paper aims to explore the estimation of spectral kurtosis using short time Fourier transform known as spectrogram. The estimation of SK is similar to the estimation of psd. The estimation falls in model-free estimation and plug-in estimator. Some numerical studies using simulations are discussed to support the methodology. Spectral kurtosis of some stationary signals are analytically obtained and used in simulation study. Kurtosis of time domain has been a popular tool for detecting non-normality. Spectral kurtosis is an extension of kurtosis in frequency domain. The relationship between time domain and frequency domain analysis is establish through power spectrum-autocovariance Fourier transform. Fourier transform is the main tool for estimation in frequency domain. The power spectral density is estimated through periodogram. In this paper, the short time Fourier transform of the spectral kurtosis is reviewed, a bearing fault (inner ring and outer ring) is simulated. The bearing response, power spectrum, and spectral kurtosis are plotted to

  15. Spectral detection of near-surface moisture content and water-table position in northern peatland ecosystems

    Science.gov (United States)

    Karl M. Meingast; Michael J. Falkowski; Evan S. Kane; Lynette R. Potvin; Brian W. Benscoter; Alistair M.S. Smith; Laura L. Bourgeau-Chavez; Mary Ellen. Miller

    2014-01-01

    Wildland fire occurrence has been increasing in peatland ecosystems during recent decades. As such, there is a need for broadly applicable tools to detect and monitor controls on combustion such as surface peat moisture and water-table position. A field portable spectroradiometer was used to measure surface reflectance of two Sphagnum moss-dominated...

  16. Spectral Analysis on Time-Course Expression Data: Detecting Periodic Genes Using a Real-Valued Iterative Adaptive Approach

    Directory of Open Access Journals (Sweden)

    Kwadwo S. Agyepong

    2013-01-01

    Full Text Available Time-course expression profiles and methods for spectrum analysis have been applied for detecting transcriptional periodicities, which are valuable patterns to unravel genes associated with cell cycle and circadian rhythm regulation. However, most of the proposed methods suffer from restrictions and large false positives to a certain extent. Additionally, in some experiments, arbitrarily irregular sampling times as well as the presence of high noise and small sample sizes make accurate detection a challenging task. A novel scheme for detecting periodicities in time-course expression data is proposed, in which a real-valued iterative adaptive approach (RIAA, originally proposed for signal processing, is applied for periodogram estimation. The inferred spectrum is then analyzed using Fisher’s hypothesis test. With a proper -value threshold, periodic genes can be detected. A periodic signal, two nonperiodic signals, and four sampling strategies were considered in the simulations, including both bursts and drops. In addition, two yeast real datasets were applied for validation. The simulations and real data analysis reveal that RIAA can perform competitively with the existing algorithms. The advantage of RIAA is manifested when the expression data are highly irregularly sampled, and when the number of cycles covered by the sampling time points is very reduced.

  17. Early drought detection by spectral analysis of satellite time series of precipitation and Normalized Difference Vegetation Index (NDVI)

    NARCIS (Netherlands)

    Van Hoek, Mattijn; Jia, Li; Zhou, J.; Zheng, Chaolei; Menenti, M.

    2016-01-01

    The time lag between anomalies in precipitation and vegetation activity plays a critical role in early drought detection as agricultural droughts are caused by precipitation shortages. The aim of this study is to explore a new approach to estimate the time lag between a forcing (precipitation)

  18. Evaluation of wavelet spectral features in pathological detection and discrimination of yellow rust and powdery mildew in winter wheat with hyperspectral reflectance data

    Science.gov (United States)

    Shi, Yue; Huang, Wenjiang; Zhou, Xianfeng

    2017-04-01

    Hyperspectral absorption features are important indicators of characterizing plant biophysical variables for the automatic diagnosis of crop diseases. Continuous wavelet analysis has proven to be an advanced hyperspectral analysis technique for extracting absorption features; however, specific wavelet features (WFs) and their relationship with pathological characteristics induced by different infestations have rarely been summarized. The aim of this research is to determine the most sensitive WFs for identifying specific pathological lesions from yellow rust and powdery mildew in winter wheat, based on 314 hyperspectral samples measured in field experiments in China in 2002, 2003, 2005, and 2012. The resultant WFs could be used as proxies to capture the major spectral absorption features caused by infestation of yellow rust or powdery mildew. Multivariate regression analysis based on these WFs outperformed conventional spectral features in disease detection; meanwhile, a Fisher discrimination model exhibited considerable potential for generating separable clusters for each infestation. Optimal classification returned an overall accuracy of 91.9% with a Kappa of 0.89. This paper also emphasizes the WFs and their relationship with pathological characteristics in order to provide a foundation for the further application of this approach in monitoring winter wheat diseases at the regional scale.

  19. Scanning laser polarimetry and spectral domain optical coherence tomography for the detection of retinal changes in Parkinson's disease.

    Science.gov (United States)

    Stemplewitz, Birthe; Keserü, Matthias; Bittersohl, Diana; Buhmann, Carsten; Skevas, Christos; Richard, Gisbert; Hassenstein, Andrea

    2015-12-01

    Whether retinal degeneration is part of the degenerative processes in patients with Parkinson's disease (PD) is still unclear. This cross-sectional study was undertaken to compare the retinal morphology of patients with PD and healthy controls using spectral domain optical coherence tomography (SD-OCT) and scanning laser polarimetry (SLP). Both eyes of patients with PD (n = 108) and healthy controls (n = 165) were examined using SD-OCT and SLP on the same day. Data on the thickness of the retinal nerve fibre layer (RNFL) of all quadrants and the macular area were acquired by OCT (Cirrus, Zeiss). The SLP device (Glaucoma diagnostics (GDx), Zeiss) measured the RNFL and calculated the nerve fibre index (NFI). All patients and probands were checked for concomitant ocular disorders by an ophthalmologist. Visual acuity, intraocular pressure (IOP), objective refraction and the anterior and posterior segment were assessed. Patients with PD showed a reduced macular volume and a reduced central subfield thickness in OCT examinations. The RNFL in the different quadrants did not differ significantly from that of controls. SLP data showed a reduced average RNFL thickness, a decreased thickness of the inferior quadrant and an increase of the NFI in patients with PD. PD may be associated with reduced thickness and volume of the macula and a reduced thickness of the RNFL in the inferior quadrant of the retina. Investigations using SD-OCT and SLP revealed distinct but significant differences between patients with PD and healthy controls. © 2015 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  20. Detecting post-fire burn severity and vegetation recovery using multitemporal remote sensing spectral indices and field-collected composite burn index data in a ponderosa pine forest

    Science.gov (United States)

    Chen, Xuexia; Vogelmann, James E.; Rollins, Matt; Ohlen, Donald; Key, Carl H.; Yang, Limin; Huang, Chengquan; Shi, Hua

    2011-01-01

    It is challenging to detect burn severity and vegetation recovery because of the relatively long time period required to capture the ecosystem characteristics. Multitemporal remote sensing data can providemultitemporal observations before, during and after a wildfire, and can improve the change detection accuracy. The goal of this study is to examine the correlations between multitemporal spectral indices and field-observed burn severity, and to provide a practical method to estimate burn severity and vegetation recovery. The study site is the Jasper Fire area in the Black Hills National Forest, South Dakota, that burned during August and September 2000. Six multitemporal Landsat images acquired from 2000 (pre-fire), 2001 (post-fire), 2002, 2003, 2005 and 2007 were used to assess burn severity. The normalized difference vegetation index (NDVI), enhanced vegetation index (EVI), normalized burn ratio (NBR), integrated forest index (IFI) and the differences of these indices between the pre-fire and post-fire years were computed and analysed with 66 field-based composite burn index (CBI) plots collected in 2002. Results showed that differences of NDVI and differences of EVI between the pre-fire year and the first two years post-fire were highly correlated with the CBI scores. The correlations were low beyond the second year post-fire. Differences of NBR had good correlation with CBI scores in all study years. Differences of IFI had low correlation with CBI in the first year post-fire and had good correlation in later years. A CBI map of the burnt area was produced using regression tree models and the multitemporal images. The dynamics of four spectral indices from 2000 to 2007 indicated that both NBR and IFI are valuable for monitoring long-term vegetation recovery. The high burn severity areas had a much slower recovery than the moderate and low burn areas.

  1. Construction of a High Temporal-spectral Resolution Spectrometer for Detection of Fast Transients from Observations of the Sun at 1.4 GHz.

    Science.gov (United States)

    Casillas-Perez, G. A.; Jeyakumar, S.; Perez-Enriquez, R.

    2014-12-01

    Transients explosive events with time durations from nanoseconds to several hours, are observed in the Sun at high energy bands such as gamma ray and xray. In the radio band, several types of radio bursts are commonly detected from the ground. A few observations of the Sun in the past have also detected a new class of fast transients which are known to have short-live electromagnetic emissions with durations less than 100 ms. The mechanisms that produce such fast transiets remain unclear. Observations of such fast transients over a wide bandwidth is necessary to uderstand the underlying physical process that produce such fast transients. Due to their very large flux densities, fast radio transients can be observed at high time resolution using small antennas in combination with digital signal processing techniques. In this work we report the progress of an spectrometer that is currently in construction at the Observatorio de la Luz of the Universidad de Guanajuato. The instrument which will have the purpose of detecting solar fast radio transients, involves the use of digital devices such as FPGA and ADC cards, in addition with a receiver with high temporal-spectral resolution centered at 1.4 GHz and a pair of 2.3 m satellite dish.

  2. Multi-channel up-conversion infrared spectrometer and method of detecting a spectral distribution of light

    DEFF Research Database (Denmark)

    2015-01-01

    A multi-channel infrared spectrometer for detecting an infrared spectrum of light received from an object. The spectrometer comprises a wavelength converter system comprising a nonlinear material and having an input side and an output side. The wavelength converter system comprises at least a first...... on the first side into light in a second output wavelength range output on the second side. The spectrometer further comprises a demultiplexer configured for demultiplexing light in the first up-conversion channel and light in the second up-conversion channel. The demultiplexer is located on the first side...

  3. Independent component analysis of edge information for face recognition

    CERN Document Server

    Karande, Kailash Jagannath

    2013-01-01

    The book presents research work on face recognition using edge information as features for face recognition with ICA algorithms. The independent components are extracted from edge information. These independent components are used with classifiers to match the facial images for recognition purpose. In their study, authors have explored Canny and LOG edge detectors as standard edge detection methods. Oriented Laplacian of Gaussian (OLOG) method is explored to extract the edge information with different orientations of Laplacian pyramid. Multiscale wavelet model for edge detection is also propos

  4. Spectral stratigraphy

    Science.gov (United States)

    Lang, Harold R.

    1991-01-01

    A new approach to stratigraphic analysis is described which uses photogeologic and spectral interpretation of multispectral remote sensing data combined with topographic information to determine the attitude, thickness, and lithology of strata exposed at the surface. The new stratigraphic procedure is illustrated by examples in the literature. The published results demonstrate the potential of spectral stratigraphy for mapping strata, determining dip and strike, measuring and correlating stratigraphic sequences, defining lithofacies, mapping biofacies, and interpreting geological structures.

  5. Stability of edge states and edge magnetism in graphene nanoribbons

    OpenAIRE

    Kunstmann, Jens; Özdoğan, Cem; Quandt, Alexander; Fehske, Holger

    2010-01-01

    We critically discuss the stability of edge states and edge magnetism in zigzag edge graphene nanoribbons (ZGNRs). We point out that magnetic edge states might not exist in real systems, and show that there are at least three very natural mechanisms - edge reconstruction, edge passivation, and edge closure - which dramatically reduce the effect of edge states in ZGNRs or even totally eliminate them. Even if systems with magnetic edge states could be made, the intrinsic magnetism would not be ...

  6. Clinical utility of contrast-enhanced spectral mammography as an adjunct for tomosynthesis-detected architectural distortion.

    Science.gov (United States)

    Patel, Bhavika K; Naylor, Michelle E; Kosiorek, Heidi E; Lopez-Alvarez, Yania M; Miller, Adrian M; Pizzitola, Victor J; Pockaj, Barbara A

    Supplement tomosynthesis-detected architectural distortions (AD) with CESM to better characterize malignant vs benign lesions. Retrospective review CESM prior to biopsied AD. Pathology: benign, radial scar, or malignant. 49 lesions (45 patients). 29 invasive cancers, 1 DCIS (range, 0.4-4.7cm); 9 radial scars; 10 benign. 37 (75.5%) ADs had associated enhancement. PPV 78.4% (29/37), sensitivity 96.7% (29/30); specificity, 57.9% (11/19); NPV, 91.7% (11/12). False-positive rate 21.6% (8/37); false-negative rate, 8.3% (1/12). Accuracy 81.6% (40/49). High sensitivity and NPV of CESM in patients with AD is promising as an adjunct tool in diagnosing malignancy and avoiding unnecessary biopsy, respectively. Copyright © 2017 Elsevier Inc. All rights reserved.

  7. Comparison of iodine K-edge subtraction and fluorescence subtraction imaging in an animal system

    International Nuclear Information System (INIS)

    Zhang, H.; Zhu, Y.; Bewer, B.; Zhang, L.; Korbas, M.; Pickering, I.J.; George, G.N.; Gupta, M.; Chapman, D.

    2008-01-01

    K-Edge Subtraction (KES) utilizes the discontinuity in the X-ray absorption across the absorption edge of the selected contrast element and creates an image of the projected density of the contrast element from two images acquired just above and below the K-edge of the contrast element. KES has proved to be powerful in coronary angiography, micro-angiography, bronchography, and lymphatic imaging. X-ray fluorescence imaging is a successful technique for the detection of dilute quantities of elements in specimens. However, its application at high X-ray energies (e.g. at the iodine K-edge) is complicated by significant Compton background, which may enter the energy window set for the contrast material's fluorescent X-rays. Inspired by KES, Fluorescence Subtraction Imaging (FSI) is a technique for high-energy (>20 keV) fluorescence imaging using two different incident beam energies just above and below the absorption edge of a contrast element (e.g. iodine). The below-edge image can be assumed as a 'background' image, which includes Compton scatter and fluorescence from other elements. The above-edge image will contain nearly identical spectral content as the below-edge image but will contain the additional fluorescence of the contrast element. This imaging method is especially promising with thick objects with dilute contrast materials, significant Compton background, and/or competing fluorescence lines from other materials. A quality factor is developed to facilitate the comparison. The theoretical value of the quality factor sets the upper limit that an imaging method can achieve when the noise is Poisson limited. The measured value of this factor makes two or more imaging methods comparable. Using the Hard X-ray Micro-Analysis (HXMA) beamline at the Canadian Light Source (CLS), the techniques of FSI and KES were critically compared, with reference to radiation dose, image acquisition time, resolution, signal-to-noise ratios, and quality factor

  8. Predicted solar cell edge radiation effects

    International Nuclear Information System (INIS)

    Gates, M.T.

    1993-01-01

    The Advanced Solar Cell Orbital Test (ASCOT) will test six types of solar cells in a high energy proton environment. During the design of the experiment a question was raised about the effects of proton radiation incident on the edge of the solar cells and whether edge radiation shielding was required. Historical geosynchronous data indicated that edge radiation damage is not detectable over the normal end of life solar cell degradation; however because the ASCOT radiation environment has a much higher and more energetic fluence of protons, considerably more edge damage is expected. A computer analysis of the problem was made by modeling the expected radiation damage at the cell edge and using a network model of small interconnected solar cells to predict degradation in the cell's electrical output. The model indicated that the deepest penetration of edge radiation was at the top of the cell near the junction where the protons have access to the cell through the low density cell/cover adhesive layer. The network model indicated that the cells could tolerate high fluences at their edge as long as there was high electrical resistance between the edge radiated region and the contact system on top of the cell. The predicted edge radiation related loss was less than 2% of maximum power for GaAs/Ge solar cells. As a result, no edge radiation protection was used for ASCOT

  9. Nanoindentation near the edge

    Science.gov (United States)

    J.E. Jakes; C.R. Frihart; J.F. Beecher; R.J. Moon; P.J. Resto; Z.H. Melgarejo; O.M. Saurez; H. Baumgart; A.A. Elmustafa; D.S. Stone

    2009-01-01

    Whenever a nanoindent is placed near an edge, such as the free edge of the specimen or heterophase interface intersecting the surface, the elastic discontinuity associated with the edge produces artifacts in the load-depth data. Unless properly handled in the data analysis, the artifacts can produce spurious results that obscure any real trends in properties as...

  10. A Robust Motion Artifact Detection Algorithm for Accurate Detection of Heart Rates From Photoplethysmographic Signals Using Time-Frequency Spectral Features.

    Science.gov (United States)

    Dao, Duy; Salehizadeh, S M A; Noh, Yeonsik; Chong, Jo Woon; Cho, Chae Ho; McManus, Dave; Darling, Chad E; Mendelson, Yitzhak; Chon, Ki H

    2017-09-01

    Motion and noise artifacts (MNAs) impose limits on the usability of the photoplethysmogram (PPG), particularly in the context of ambulatory monitoring. MNAs can distort PPG, causing erroneous estimation of physiological parameters such as heart rate (HR) and arterial oxygen saturation (SpO2). In this study, we present a novel approach, "TifMA," based on using the time-frequency spectrum of PPG to first detect the MNA-corrupted data and next discard the nonusable part of the corrupted data. The term "nonusable" refers to segments of PPG data from which the HR signal cannot be recovered accurately. Two sequential classification procedures were included in the TifMA algorithm. The first classifier distinguishes between MNA-corrupted and MNA-free PPG data. Once a segment of data is deemed MNA-corrupted, the next classifier determines whether the HR can be recovered from the corrupted segment or not. A support vector machine (SVM) classifier was used to build a decision boundary for the first classification task using data segments from a training dataset. Features from time-frequency spectra of PPG were extracted to build the detection model. Five datasets were considered for evaluating TifMA performance: (1) and (2) were laboratory-controlled PPG recordings from forehead and finger pulse oximeter sensors with subjects making random movements, (3) and (4) were actual patient PPG recordings from UMass Memorial Medical Center with random free movements and (5) was a laboratory-controlled PPG recording dataset measured at the forehead while the subjects ran on a treadmill. The first dataset was used to analyze the noise sensitivity of the algorithm. Datasets 2-4 were used to evaluate the MNA detection phase of the algorithm. The results from the first phase of the algorithm (MNA detection) were compared to results from three existing MNA detection algorithms: the Hjorth, kurtosis-Shannon entropy, and time-domain variability-SVM approaches. This last is an approach

  11. Structural health monitoring method for wind turbine trailing edge: Crack growth detection using Fibre Bragg Grating sensor embedded in composite materials

    DEFF Research Database (Denmark)

    Pereira, Gilmar Ferreira; Mikkelsen, Lars Pilgaard; McGugan, Malcolm

    2015-01-01

    In this article a novel method to assess a crack growing/damage event in composite material using Fibre Bragg Grating (FBG) sensors embedded in a host material and its application into a composite material structure, Wind Turbine Trailing Edge, is presented. A Structure-Material-FBG model......, such as compression fields ahead the crack or non-uniform strain fields, and then identify the presence of such damage in the structure. Experimental tests were conducted to fully characterize this concept and support the model. Double Cantilever Beams (DCB), made with two glass fibre beams glued with structural...

  12. Selective separation, detection of zotepine and mass spectral characterization of degradants by LC–MS/MS/QTOF

    Directory of Open Access Journals (Sweden)

    M.V.N. Kumar Talluri

    2014-04-01

    Full Text Available A simple, precise, accurate stability-indicating gradient reversed-phase high-performance liquid chromatographic (RP–HPLC method was developed for the quantitative determination of zotepine (ZTP in bulk and pharmaceutical dosage forms in the presence of its degradation products (DPs. The method was developed using Phenomenex C18 column (250 mm×4.6 mm i.d., 5 µm with a mobile phase containing a gradient mixture of solvents, A (0.05% trifluoroacetic acid (TFA, pH=3.0 and B (acetonitrile. The eluted compounds were monitored at 254 nm; the run time was within 20.0 min, in which ZTP and its DPs were well separated, with a resolution of >1.5. The stress testing of ZTP was carried out under acidic, alkaline, neutral hydrolysis, oxidative, photolytic and thermal stress conditions. ZTP was found to degrade significantly in acidic, photolytic, thermal and oxidative stress conditions and remain stable in basic and neutral conditions. The developed method was validated with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness as per ICH guidelines. This method was also suitable for the assay determination of ZTP in pharmaceutical dosage forms. The DPs were characterized by LC–MS/MS and their fragmentation pathways were proposed. Keywords: Zotepine, Stability-indicating RP–HPLC method, Characterization, ESI-Q-TOF-MS, Bulk drugs and formulations

  13. SARAS 2: a spectral radiometer for probing cosmic dawn and the epoch of reionization through detection of the global 21-cm signal

    Science.gov (United States)

    Singh, Saurabh; Subrahmanyan, Ravi; Shankar, N. Udaya; Rao, Mayuri Sathyanarayana; Girish, B. S.; Raghunathan, A.; Somashekar, R.; Srivani, K. S.

    2018-04-01

    The global 21-cm signal from Cosmic Dawn (CD) and the Epoch of Reionization (EoR), at redshifts z ˜ 6-30, probes the nature of first sources of radiation as well as physics of the Inter-Galactic Medium (IGM). Given that the signal is predicted to be extremely weak, of wide fractional bandwidth, and lies in a frequency range that is dominated by Galactic and Extragalactic foregrounds as well as Radio Frequency Interference, detection of the signal is a daunting task. Critical to the experiment is the manner in which the sky signal is represented through the instrument. It is of utmost importance to design a system whose spectral bandpass and additive spurious signals can be well calibrated and any calibration residual does not mimic the signal. Shaped Antenna measurement of the background RAdio Spectrum (SARAS) is an ongoing experiment that aims to detect the global 21-cm signal. Here we present the design philosophy of the SARAS 2 system and discuss its performance and limitations based on laboratory and field measurements. Laboratory tests with the antenna replaced with a variety of terminations, including a network model for the antenna impedance, show that the gain calibration and modeling of internal additive signals leave no residuals with Fourier amplitudes exceeding 2 mK, or residual Gaussians of 25 MHz width with amplitudes exceeding 2 mK. Thus, even accounting for reflection and radiation efficiency losses in the antenna, the SARAS 2 system is capable of detection of complex 21-cm profiles at the level predicted by currently favoured models for thermal baryon evolution.

  14. Theoretical Mn K-edge XANES for Li2MnO3: DFT + U study

    International Nuclear Information System (INIS)

    Tamura, Tomoyuki; Ohwaki, Tsukuru; Ito, Atsushi; Ohsawa, Yasuhiko; Kobayashi, Ryo; Ogata, Shuji

    2012-01-01

    Spectral features of Mn K-edge x-ray absorption near-edge structure (XANES) for Li 2 MnO 3 were calculated using the first-principles full projector augmented wave method with the general gradient approximation plus U method. We demonstrated that the U parameter affects the spectral features in the pre-edge region while it does not affect those in the major absorption region. From the comparison with the experimental spectra and those of reference compounds, we showed that the spectral features of Mn K-edge XANES and the differences in the valence state can be reproduced well. (paper)

  15. An edge pedestal model

    International Nuclear Information System (INIS)

    Stacev, W.M.

    2001-01-01

    A new model for calculation of the gradient scale lengths in the edge pedestal region and of the edge transport barrier width in H-mode tokamak plasmas will be described. Model problem calculations which demonstrate the promise of this model for predicting experimental pedestal properties will be discussed. The density and Prague gradient scale lengths (L) in the edge are calculated from the particle and ion and electron energy radial transport equations, making use of (presumed) known particle and energy fluxes flowing across the edge transport barrier from the core into the SOL and of edge transport coefficients. The average values of the particle and heat fluxes in the edge transport barrier are calculated in terms of the fluxes crossing into the SOL and the atomic physics reaction rates (ionisation, charge-exchange, elastic scattering, impurity radiation) in the edge by integrating the respective transport equations from the pedestal to the separatrix. An important implication of this model is that the pedestal gradient scale lengths depend not just on local pedestal platers properties but also on particle and energy fluxes from the core plasma and on recycling neutral fluxes that penetrate into the plasma edge, both of which in turn depend on the pedestal properties. The MHD edge pressure gradient constraint α≤ α C is used to determine the pressure width of the edge transport barrier, Δ TB = Δ TB (α c ). Three different models for the MHD edge pressure gradient constraint have been investigated: (1) nominal ideal ballooning mode theory, (2) ballooning mode theory taking into account the edge geometry and shear to access He second stability region; and pedestal β-limit theory when the ballooning modes are stabilised by diamagnetic effects. A series of calculations have been made for a DIII-D model problem. The calculated gradient scale lengths and edge transport barrier widths are of the magnitude of values observed experimentally, and certain trends

  16. The red edge in arid region vegetation: 340-1060 nm spectra

    Science.gov (United States)

    Ray, Terrill W.; Murray, Bruce C.; Chehbouni, A.; Njoku, Eni

    1993-01-01

    The remote sensing study of vegetated regions of the world has typically been focused on the use of broad-band vegetation indices such as NDVI. Various modifications of these indices have been developed in attempts to minimize the effect of soil background, e.g., SAVI, or to reduce the effect of the atmosphere, e.g., ARVI. Most of these indices depend on the so-called 'red edge,' the sharp transition between the strong absorption of chlorophyll pigment in visible wavelengths and the strong scattering in the near-infrared from the cellular structure of leaves. These broadband indices tend to become highly inaccurate as the green canopy cover becomes sparse. The advent of high spectral resolution remote sensing instrument such as the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) has allowed the detection of narrow spectral features in vegetation and there are reports of detection of the red edge even for pixels with very low levels of green vegetation cover by Vane et al. and Elvidge et al., and to characterize algal biomass in coastal areas. Spectral mixing approaches similar to those of Smith et al. can be extended into the high spectral resolution domain allowing for the analysis of more endmembers, and potentially, discrimination between material with narrow spectral differences. Vegetation in arid regions tends to be sparse, often with small leaves such as the creosote bush. Many types of arid region vegetation spend much of the year with their leaves in a senescent state, i.e., yellow, with lowered chlorophyll pigmentation. The sparseness of the leaves of many arid region plants has the dual effect of lowering the green leaf area which can be observed and of allowing more of the sub-shrub soil to be visible which further complicates the spectrum of a region covered with arid region vegetation. Elvidge examined the spectral characteristics of dry plant materials showing significant differences in the region of the red edge and the diagnostic ligno

  17. Spectral analysis of fundus autofluorescence pattern as a tool to detect early stages of degeneration in the retina and retinal pigment epithelium.

    Science.gov (United States)

    Feldman, Tatiana B; Yakovleva, Marina A; Larichev, Andrey V; Arbukhanova, Patimat M; Radchenko, Alexandra Sh; Borzenok, Sergey A; Kuzmin, Vladimir A; Ostrovsky, Mikhail A

    2018-05-22

    The aim of this work is the determination of quantitative diagnostic criteria based on the spectral characteristics of fundus autofluorescence to detect early stages of degeneration in the retina and retinal pigment epithelium (RPE). RPE cell suspension samples were obtained from the cadaver eyes with and without signs of age-related macular degeneration (AMD). Fluorescence analysis at an excitation wavelength of 488 nm was performed. The fluorescence lifetimes of lipofuscin-granule fluorophores were measured by counting time-correlated photon method. Comparative analysis of fluorescence spectra of RPE cell suspensions from the cadaver eyes with and without signs of AMD showed a significant difference in fluorescence intensity at 530-580 nm in response to fluorescence excitation at 488 nm. It was notably higher in eyes with visual pathology than in normal eyes regardless of the age of the eye donor. Measurements of fluorescence lifetimes of lipofuscin fluorophores showed that the contribution of photooxidation and photodegradation products of bisretinoids to the total fluorescence at 530-580 nm of RPE cell suspensions was greater in eyes with visual pathology than in normal eyes. Because photooxidation and photodegradation products of bisretinoids are markers of photodestructive processes, which can cause RPE cell death and initiate degenerative processes in the retina, quantitative determination of increases in these bisretinoid products in lipofuscin granules may be used to establish quantitative diagnostic criteria for degenerative processes in the retina and RPE.

  18. Tomographic-spectral approach for dark matter detection in the cross-correlation between cosmic shear and diffuse γ-ray emission

    Energy Technology Data Exchange (ETDEWEB)

    Camera, S. [Jodrell Bank Centre for Astrophysics, The University of Manchester, Alan Turing Building, Oxford Road, Manchester M13 9PL (United Kingdom); Fornasa, M. [School of Physics and Astronomy, University of Nottingham, University Campus, Nottingham NG7 2RD (United Kingdom); Fornengo, N.; Regis, M., E-mail: stefano.camera@manchester.ac.uk, E-mail: fornasam@gmail.com, E-mail: fornengo@to.infn.it, E-mail: regis@to.infn.it [Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125 Torino (Italy)

    2015-06-01

    We recently proposed to cross-correlate the diffuse extragalactic γ-ray background with the gravitational lensing signal of cosmic shear. This represents a novel and promising strategy to search for annihilating or decaying particle dark matter (DM) candidates. In the present work, we demonstrate the potential of a tomographic-spectral approach: measuring the cross-correlation in separate bins of redshift and energy significantly improves the sensitivity to a DM signal. Indeed, the technique proposed here takes advantage of the different scaling of the astrophysical and DM components with redshift and, simultaneously of their different energy spectra and different angular extensions. The sensitivity to a particle DM signal is extremely promising even when the DM-induced emission is quite faint. We first quantify the prospects of detecting DM by cross-correlating the Fermi Large Area Telescope (LAT) diffuse γ-ray background with the cosmic shear expected from the Dark Energy Survey. Under the hypothesis of a significant subhalo boost, such a measurement can deliver a 5σ detection of DM, if the DM particle is lighter than 300 GeV and has a thermal annihilation rate. We then forecast the capability of the European Space Agency Euclid satellite (whose launch is planned for 2020), in combination with an hypothetical future γ-ray detector with slightly improved specifications compared to current telescopes. We predict that the cross-correlation of their data will allow a measurement of the DM mass with an uncertainty of a factor of 1.5–2, even for moderate subhalo boosts, for DM masses up to few hundreds of GeV and thermal annihilation rates.

  19. Tomographic-spectral approach for dark matter detection in the cross-correlation between cosmic shear and diffuse γ-ray emission

    Science.gov (United States)

    Camera, S.; Fornasa, M.; Fornengo, N.; Regis, M.

    2015-06-01

    We recently proposed to cross-correlate the diffuse extragalactic γ-ray background with the gravitational lensing signal of cosmic shear. This represents a novel and promising strategy to search for annihilating or decaying particle dark matter (DM) candidates. In the present work, we demonstrate the potential of a tomographic-spectral approach: measuring the cross-correlation in separate bins of redshift and energy significantly improves the sensitivity to a DM signal. Indeed, the technique proposed here takes advantage of the different scaling of the astrophysical and DM components with redshift and, simultaneously of their different energy spectra and different angular extensions. The sensitivity to a particle DM signal is extremely promising even when the DM-induced emission is quite faint. We first quantify the prospects of detecting DM by cross-correlating the Fermi Large Area Telescope (LAT) diffuse γ-ray background with the cosmic shear expected from the Dark Energy Survey. Under the hypothesis of a significant subhalo boost, such a measurement can deliver a 5σ detection of DM, if the DM particle is lighter than 300 GeV and has a thermal annihilation rate. We then forecast the capability of the European Space Agency Euclid satellite (whose launch is planned for 2020), in combination with an hypothetical future γ-ray detector with slightly improved specifications compared to current telescopes. We predict that the cross-correlation of their data will allow a measurement of the DM mass with an uncertainty of a factor of 1.5-2, even for moderate subhalo boosts, for DM masses up to few hundreds of GeV and thermal annihilation rates.

  20. Tomographic-spectral approach for dark matter detection in the cross-correlation between cosmic shear and diffuse γ-ray emission

    International Nuclear Information System (INIS)

    Camera, S.; Fornasa, M.; Fornengo, N.; Regis, M.

    2015-01-01

    We recently proposed to cross-correlate the diffuse extragalactic γ-ray background with the gravitational lensing signal of cosmic shear. This represents a novel and promising strategy to search for annihilating or decaying particle dark matter (DM) candidates. In the present work, we demonstrate the potential of a tomographic-spectral approach: measuring the cross-correlation in separate bins of redshift and energy significantly improves the sensitivity to a DM signal. Indeed, the technique proposed here takes advantage of the different scaling of the astrophysical and DM components with redshift and, simultaneously of their different energy spectra and different angular extensions. The sensitivity to a particle DM signal is extremely promising even when the DM-induced emission is quite faint. We first quantify the prospects of detecting DM by cross-correlating the Fermi Large Area Telescope (LAT) diffuse γ-ray background with the cosmic shear expected from the Dark Energy Survey. Under the hypothesis of a significant subhalo boost, such a measurement can deliver a 5σ detection of DM, if the DM particle is lighter than 300 GeV and has a thermal annihilation rate. We then forecast the capability of the European Space Agency Euclid satellite (whose launch is planned for 2020), in combination with an hypothetical future γ-ray detector with slightly improved specifications compared to current telescopes. We predict that the cross-correlation of their data will allow a measurement of the DM mass with an uncertainty of a factor of 1.5–2, even for moderate subhalo boosts, for DM masses up to few hundreds of GeV and thermal annihilation rates

  1. Polarimetric Edge Detector Based on the Complex Wishart Distribution

    DEFF Research Database (Denmark)

    Skriver, Henning; Schou, Jesper; Nielsen, Allan Aasbjerg

    2001-01-01

    polarimetric edge detector provides a constant false alarm rate and it utilizes the full polarimetric information. The edge detector has been applied to polarimetric SAR data from the Danish dual-frequency, airborne polarimetric SAR, EMISAR. The results show clearly an improved edge detection performance...

  2. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  3. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  4. Photovoltaic spectral responsivity measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, K.; Dunlavy, D.; Field, H.; Moriarty, T. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper discusses the various elemental random and nonrandom error sources in typical spectral responsivity measurement systems. The authors focus specifically on the filter and grating monochrometer-based spectral responsivity measurement systems used by the Photovoltaic (PV) performance characterization team at NREL. A variety of subtle measurement errors can occur that arise from a finite photo-current response time, bandwidth of the monochromatic light, waveform of the monochromatic light, and spatial uniformity of the monochromatic and bias lights; the errors depend on the light source, PV technology, and measurement system. The quantum efficiency can be a function of he voltage bias, light bias level, and, for some structures, the spectral content of the bias light or location on the PV device. This paper compares the advantages and problems associated with semiconductor-detector-based calibrations and pyroelectric-detector-based calibrations. Different current-to-voltage conversion and ac photo-current detection strategies employed at NREL are compared and contrasted.

  5. A spectral route to determining chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We show how one-dimensional structured media can be used to measure chirality, via the spectral shift of the photonic band gap edges. Analytically, we show that a chiral contrast can, in some cases, be mapped unto an index contrast, thereby greatly simplifying the analysis of such structures. Using...... this mapping, we derive a first-order shift of the band gap edges with chirality. Potentially, this effect could be used for measuring enantiomeric excess....

  6. Images of Edge Turbulence in NSTX

    International Nuclear Information System (INIS)

    Zweben, S.J.; Bush, C.E.; Maqueda, R.; Munsat, T.; Stotler, D.; Lowrance, J.; Mastracola, V.; Renda, G.

    2004-01-01

    The 2-D structure of edge plasma turbulence has been measured in the National Spherical Torus Experiment (NSTX) by viewing the emission of the Da spectral line of deuterium. Images have been made at framing rates of up to 250,000 frames/sec using an ultra-high speed CCD camera developed by Princeton Scientific Instruments. A sequence of images showing the transition between L-mode and H-mode states is shown

  7. Remote Sensing of Mars: Detection of Impact Craters on the Mars Global Surveyor DTM by Integrating Edge- and Region-Based Algorithms

    Science.gov (United States)

    Athanassas, C. D.; Vaiopoulos, A.; Kolokoussis, P.; Argialas, D.

    2018-03-01

    This study integrates two different computer vision approaches, namely the circular Hough transform (CHT) and the determinant of Hessian (DoH), to detect automatically the largest number possible of craters of any size on the digital terrain model (DTM) generated by the Mars Global Surveyor mission. Specifically, application of the standard version of CHT to the DTM captured a great number of craters with diameter smaller than 50 km only, failing to capture larger craters. On the other hand, DoH was successful in detecting craters that were undetected by CHT, but its performance was deterred by the irregularity of the topographic surface encompassed: strongly undulated and inclined (trended) topographies hindered crater detection. When run on a de-trended DTM (and keeping the topology unaltered) DoH scored higher. Current results, although not optimal, encourage combined use of CHT and DoH for routine crater detection undertakings.

  8. Direct detection of albedo neutron decay electrons at the inner edge of the radiation belt and experimental determination of neutron density in near-Earth space

    Science.gov (United States)

    Li, X.; Selesnick, R.; Schiller, Q. A.; Zhang, K.; Zhao, H.; Baker, D. N.; Temerin, M. A.

    2017-12-01

    The galaxy is filled with cosmic ray particles, mostly protons with kinetic energy above hundreds of mega-electron volts (MeV). Soon after the discovery of Earth's Van Allen radiation belts almost six decades ago, it was recognized that the main source of inner belt protons, with kinetic energies of tens to hundreds of MeV, is Cosmic Ray Albedo Neutron Decay (CRAND). In this process, cosmic rays reaching the upper atmosphere from throughout the galaxy interact with neutral atoms to produce albedo neutrons which, being unstable to 𝛽 decay, are a potential source of geomagnetically trapped protons and electrons. Protons retain most of the neutrons' kinetic energy while the electrons have lower energies, mostly below 1 MeV. The viability of the electron source was, however, uncertain because measurements showed that electron intensity can vary greatly while the neutron decay rate should be almost constant. Recent measurements from the Relativistic Electron and Proton Telescope integrated little experiment (REPTile) onboard the Colorado Student Space Weather Experiment (CSSWE) CubeSat now show that CRAND is the main electron source for the radiation belt near its inner edge, and also contributes to the inner belt elsewhere. Furthermore, measurement of the CRAND electron intensity provides the first experimental determination of the neutron density in near-Earth space, 2x10-9/cm3, confirming earlier theoretical estimates.

  9. Mapping accuracy via spectrally and structurally based filtering techniques: comparisons through visual observations

    Science.gov (United States)

    Chockalingam, Letchumanan

    2005-01-01

    The data of Gunung Ledang region of Malaysia acquired through LANDSAT are considered to map certain hydrogeolocial features. To map these significant features, image-processing tools such as contrast enhancement, edge detection techniques are employed. The advantages of these techniques over the other methods are evaluated from the point of their validity in properly isolating features of hydrogeolocial interest are discussed. As these techniques take the advantage of spectral aspects of the images, these techniques have several limitations to meet the objectives. To discuss these limitations, a morphological transformation, which generally considers the structural aspects rather than spectral aspects from the image, are applied to provide comparisons between the results derived from spectral based and the structural based filtering techniques.

  10. Performance simulation of an x-ray detector for spectral CT with combined Si and Cd[Zn]Te detection layers.

    Science.gov (United States)

    Herrmann, Christoph; Engel, Klaus-Jürgen; Wiegert, Jens

    2010-12-21

    The most obvious problem in obtaining spectral information with energy-resolving photon counting detectors in clinical computed tomography (CT) is the huge x-ray flux present in conventional CT systems. At high tube voltages (e.g. 140 kVp), despite the beam shaper, this flux can be close to 10⁹ Mcps mm⁻² in the direct beam or in regions behind the object, which are close to the direct beam. Without accepting the drawbacks of truncated reconstruction, i.e. estimating missing direct-beam projection data, a photon-counting energy-resolving detector has to be able to deal with such high count rates. Sub-structuring pixels into sub-pixels is not enough to reduce the count rate per pixel to values that today's direct converting Cd[Zn]Te material can cope with (≤ 10 Mcps in an optimistic view). Below 300 µm pixel pitch, x-ray cross-talk (Compton scatter and K-escape) and the effect of charge diffusion between pixels are problematic. By organising the detector in several different layers, the count rate can be further reduced. However this alone does not limit the count rates to the required level, since the high stopping power of the material becomes a disadvantage in the layered approach: a simple absorption calculation for 300 µm pixel pitch shows that the required layer thickness of below 10 Mcps/pixel for the top layers in the direct beam is significantly below 100 µm. In a horizontal multi-layer detector, such thin layers are very difficult to manufacture due to the brittleness of Cd[Zn]Te. In a vertical configuration (also called edge-on illumination (Ludqvist et al 2001 IEEE Trans. Nucl. Sci. 48 1530-6, Roessl et al 2008 IEEE NSS-MIC-RTSD 2008, Conf. Rec. Talk NM2-3)), bonding of the readout electronics (with pixel pitches below 100 µm) is not straightforward although it has already been done successfully (Pellegrini et al 2004 IEEE NSS MIC 2004 pp 2104-9). Obviously, for the top detector layers, materials with lower stopping power would be advantageous

  11. Electromagnetic radiation of protons in edge fields of synchrotron dipole magnets

    International Nuclear Information System (INIS)

    Smolyakov, N.V.

    1986-01-01

    Effect of the edge shape of magnetic field of a dipole on the short-wave part of electromagnetic radiation spectrum of a proton beam is investigated. In some cases short-wave photons are shown to be shaped in the ranges of largest edge curvature of the magnetic field. Universality of edge radiation spectrum is proved. Spectral characteristics of proton edge radiation in a superconducting magnetic dipole of the storage-accelerator complex are obtained

  12. Edge effects in composites

    International Nuclear Information System (INIS)

    Guz, A.N.; Kokhanenko, Yu.V.

    1995-01-01

    In the present article we survey papers on edge effects investigated by the rigorous approach. We interpret edge effects as stressed states created in a composite as a result of zones in which the stresses exhibit a rapidly changing behavior in comparison with the slow variation of the stresses outside such zones. Here the range of the edge effect is defined as the distance from the point of its inception to the boundary of the edge zone in a given direction. The transition of the stresses to the slowly varying state is determined within prescribed error limits. The size and configuration of the edge zone depends on the tolerated error. Clearly, the main difficulty associated with the rigorous approach is finding solutions of the elasticity problems. The finite-difference approach is suggested for the approximate solution of these problems. In light of the comparative time consumption of the finite-difference approach, it is best directed at certain classes of problems rather than at particular individual problems. Not too many papers on the investigation of edge effects by the rigorous approach have been published to date. Below, following in their footsteps, we formulate edge effect problems in composites, determine classes of problems, and investigate edge effects in composite materials and structural elements using them in Cartesian (planar and three-dimensional problems) and cylindrical (axisymmetric problems) coordinate frames. We note that the division of approaches to the study of edge effects into qualitative (nonrigorous) and quantitative (rigorous) reflects the authors own point of view. Of course, other schemes of classification of the approaches to the investigation of the regions of rapidly varying states in composites are possible

  13. Edge colouring by total labellings

    DEFF Research Database (Denmark)

    Brandt, Stephan; Rautenbach, D.; Stiebitz, M.

    2010-01-01

    We introduce the concept of an edge-colouring total k-labelling. This is a labelling of the vertices and the edges of a graph G with labels 1, 2, ..., k such that the weights of the edges define a proper edge colouring of G. Here the weight of an edge is the sum of its label and the labels of its...

  14. Adobe Edge Quickstart Guide

    CERN Document Server

    Labrecque, Joseph

    2012-01-01

    Adobe Edge Quickstart Guide is a practical guide on creating engaging content for the Web with Adobe's newest HTML5 tool. By taking a chapter-by-chapter look at each major aspect of Adobe Edge, the book lets you digest the available features in small, easily understandable chunks, allowing you to start using Adobe Edge for your web design needs immediately. If you are interested in creating engaging motion and interactive compositions using web standards with professional tooling, then this book is for you. Those with a background in Flash Professional wanting to get started quickly with Adobe

  15. Evaluating the capabilities of vegetation spectral indices on chlorophyll content estimation at Sentinel-2 spectral resolutions

    Science.gov (United States)

    Sun, Qi; Jiao, Quanjun; Dai, Huayang

    2018-03-01

    Chlorophyll is an important pigment in green plants for photosynthesis and obtaining the energy for growth and development. The rapid, nondestructive and accurate estimation of chlorophyll content is significant for understanding the crops growth, monitoring the disease and insect, and assessing the yield of crops. Sentinel-2 equipped with the Multi-Spectral Instrument (MSI), which will provide images with high spatial, spectral and temporal resolution. It covers the VNIR/SWIR spectral region in 13 bands and incorporates two new spectral bands in the red-edge region and a spatial resolution of 20nm, which can be used to derive vegetation indices using red-edge bands. In this paper, we will focus on assessing the potential of vegetation spectral indices for retrieving chlorophyll content from Sentinel-2 at different angles. Subsequently, we used in-situ spectral data and Sentinel-2 data to test the relationship between VIs and chlorophyll content. The REP, MTCI, CIred-edge, CIgreen, Macc01, TCARI/OSAVI [705,750], NDRE1 and NDRE2 were calculated. NDRE2 index displays a strongly similar result for hyperspectral and simulated Sentinel-2 spectral bands (R2 =0.53, R2 =0.51, for hyperspectral and Sentinel-2, respectively). At different observation angles, NDRE2 has the smallest difference in performance (R2 = 0.51, R2 =0.64, at 0° and 15° , respectively).

  16. Adobe Edge Preview 3

    CERN Document Server

    Grover, Chris

    2011-01-01

    Want to use an Adobe tool to design animated web graphics that work on iPhone and iPad? You've come to the right book. Adobe Edge Preview 3: The Missing Manual shows you how to build HTML5 graphics using simple visual tools. No programming experience? No problem. Adobe Edge writes the underlying code for you. With this eBook, you'll be designing great-looking web elements in no time. Get to know the workspace. Learn how Adobe Edge Preview 3 performs its magic.Create and import graphics. Make drawings with Edge's tools, or use art you designed in other programs.Work with text. Build menus, lab

  17. Pavement edge treatment.

    Science.gov (United States)

    2013-01-01

    Four projects were built over two construction seasons using special devices attached to the paving machine that produces a 30 slope on the outside pavement edge instead of the near vertical drop-off common with conventional paving equipment. This ...

  18. Edge Simulation Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Krasheninnikov, Sergei I. [Univ. of California, San Diego, CA (United States); Angus, Justin [Univ. of California, San Diego, CA (United States); Lee, Wonjae [Univ. of California, San Diego, CA (United States)

    2018-01-05

    The goal of the Edge Simulation Laboratory (ESL) multi-institutional project is to advance scientific understanding of the edge plasma region of magnetic fusion devices via a coordinated effort utilizing modern computing resources, advanced algorithms, and ongoing theoretical development. The UCSD team was involved in the development of the COGENT code for kinetic studies across a magnetic separatrix. This work included a kinetic treatment of electrons and multiple ion species (impurities) and accurate collision operators.

  19. Change Detection of High-Resolution Remote Sensing Images Based on Adaptive Fusion of Multiple Features

    Science.gov (United States)

    Wang, G. H.; Wang, H. B.; Fan, W. F.; Liu, Y.; Chen, C.

    2018-04-01

    In view of the traditional change detection algorithm mainly depends on the spectral information image spot, failed to effectively mining and fusion of multi-image feature detection advantage, the article borrows the ideas of object oriented analysis proposed a multi feature fusion of remote sensing image change detection algorithm. First by the multi-scale segmentation of image objects based; then calculate the various objects of color histogram and linear gradient histogram; utilizes the color distance and edge line feature distance between EMD statistical operator in different periods of the object, using the adaptive weighted method, the color feature distance and edge in a straight line distance of combination is constructed object heterogeneity. Finally, the curvature histogram analysis image spot change detection results. The experimental results show that the method can fully fuse the color and edge line features, thus improving the accuracy of the change detection.

  20. The Edge supersonic transport

    Science.gov (United States)

    Agosta, Roxana; Bilbija, Dushan; Deutsch, Marc; Gallant, David; Rose, Don; Shreve, Gene; Smario, David; Suffredini, Brian

    1992-01-01

    As intercontinental business and tourism volumes continue their rapid expansion, the need to reduce travel times becomes increasingly acute. The Edge Supersonic Transport Aircraft is designed to meet this demand by the year 2015. With a maximum range of 5750 nm, a payload of 294 passengers and a cruising speed of M = 2.4, The Edge will cut current international flight durations in half, while maintaining competitive first class, business class, and economy class comfort levels. Moreover, this transport will render a minimal impact upon the environment, and will meet all Federal Aviation Administration Part 36, Stage III noise requirements. The cornerstone of The Edge's superior flight performance is its aerodynamically efficient, dual-configuration design incorporating variable-geometry wingtips. This arrangement combines the benefits of a high aspect ratio wing at takeoff and low cruising speeds with the high performance of an arrow-wing in supersonic cruise. And while the structural weight concerns relating to swinging wingtips are substantial, The Edge looks to ever-advancing material technologies to further increase its viability. Heeding well the lessons of the past, The Edge design holds economic feasibility as its primary focus. Therefore, in addition to its inherently superior aerodynamic performance, The Edge uses a lightweight, largely windowless configuration, relying on a synthetic vision system for outside viewing by both pilot and passengers. Additionally, a fly-by-light flight control system is incorporated to address aircraft supersonic cruise instability. The Edge will be produced at an estimated volume of 400 aircraft and will be offered to airlines in 2015 at $167 million per transport (1992 dollars).

  1. Spectral Reflectance and Vegetation Index Changes in Deciduous Forest Foliage Following Tree Removal: Potential for Deforestation Monitoring

    Science.gov (United States)

    Peng, D.; Hu, Y.; Li, Z.

    2016-05-01

    It is important to detect and quantify deforestation to guide strategic decisions regarding environment, socioeconomic development, and climate change. In the present study, we conducted a field experiment to examine spectral reflectance and vegetation index changes in poplar and locust tree foliage with different leaf area indices over the course of three sunny days, following tree removal from the canopy. The spectral reflectance of foliage from harvested trees was measured using an ASD FieldSpec Prospectroradiometer; synchronous meteorological data were also obtained. We found that reflectance in short-wave infrared and red-edge reflectance was more time sensitive after tree removal than reflectance in other spectral regions, and that the normalized difference water index (NDWI) and the red-edge chlorophyll index (CIRE) were the preferred indicators of these changes from several indices evaluated. Synthesized meteorological environments were found to influence water and chlorophyll contents after tree removal, and this subsequently changed the spectral canopy reflectance. Our results indicate the potential for such tree removal to be detected with NDWI or CIRE from the second day of a deforestation event.

  2. Properties on the edge: graphene edge energies, edge stresses, edge warping, and the Wulff shape of graphene flakes

    International Nuclear Information System (INIS)

    Branicio, Paulo S; Jhon, Mark H; Gan, Chee Kwan; Srolovitz, David J

    2011-01-01

    It has been shown that the broken bonds of an unreconstructed graphene edge generate compressive edge stresses leading to edge warping. Here, we investigate edge energies and edge stresses of graphene nanoribbons with arbitrary orientations from armchair to zigzag, considering both flat and warped edge shapes in the presence and absence of hydrogen. We use the second generation reactive empirical bond order potential to calculate the edge energies and stresses for clean and hydrogenated edges. Using these energies, we perform a Wulff construction to determine the equilibrium shapes of flat graphene flakes as a function of hydrogen chemical potential. While edge stresses for clean, flat edges are compressive, they become tensile if allowed to warp. Conversely, we find that edge energies change little (∼1%) with edge warping. Hydrogenation of the edges virtually eliminates both the edge energy and edge stresses. For warped edges an approximately linear relationship is found between amplitudes and wavelengths. The equilibrium shape of a graphene flake is determined by the value of the hydrogen chemical potential. For very small (and large) values of it the flakes have a nearly hexagonal (dodecagon) shape with zigzag oriented edges, while for intermediate values graphene flakes are found with complex shapes

  3. New K-edge-balanced contrast phantom for image quality assurance in projection radiography

    Science.gov (United States)

    Cresens, Marc; Schaetzing, Ralph

    2003-06-01

    X-ray-absorber step-wedge phantoms serve in projection radiography to assess a detection system's overall exposure-related signal-to-noise ratio performance and contrast response. Data derived from a phantom image, created by exposing a step-wedge onto the image receptor, are compared with predefined acceptance criteria during periodic image quality assurance (QA). For contrast-related measurements, in particular, the x-ray tube potential requires accurate setting and low ripple, since small deviations from the specified kVp, causing energy spectrum changes, lead to significant image signal variation at high contrast ratios. A K-edge-balanced, rare-earth-metal contrast phantom can generate signals that are significantly more robust to the spectral variability and instability of exposure equipment in the field. The image signals from a hafnium wedge, for example, are up to eight times less sensitive to spectral fluctuations than those of today"s copper phantoms for a 200:1 signal ratio. At 120 kVp (RQA 9), the hafnium phantom still preserves 70% of the subject contrast present at 75 kVp (RQA 5). A copper wedge preserves only 7% of its contrast over the same spectral range. Spectral simulations and measurements on prototype systems, as well as potential uses of this new class of phantoms (e.g., QA, single-shot exposure response characterization) are described.

  4. Theory of edge radiation

    Energy Technology Data Exchange (ETDEWEB)

    Geloni, G.; Kocharyan, V.; Saldin, E.; Schneidmiller, E.; Yurkov, M.

    2008-08-15

    We formulate a complete theory of Edge Radiation based on a novel method relying on Fourier Optics techniques. Similar types of radiation like Transition UndulatorRadiation are addressed in the framework of the same formalism. Special attention is payed in discussing the validity of approximations upon which the theory is built. Our study makes consistent use of both similarity techniques and comparisons with numerical results from simulation. We discuss both near and far zone. Physical understanding of many asymptotes is discussed. Based on the solution of the field equation with a tensor Green's function technique, we also discuss an analytical model to describe the presence of a vacuum chamber. In particular, explicit calculations for a circular vacuum chamber are reported. Finally, we consider the use of Edge Radiation as a tool for electron beam diagnostics. We discuss Coherent Edge Radiation, Extraction of Edge Radiation by a mirror, and other issues becoming important at high electron energy and long radiation wavelength. Based on this work we also study the impact of Edge Radiation on XFEL setups and we discuss recent results. (orig.)

  5. Edge printability: techniques used to evaluate and improve extreme wafer edge printability

    Science.gov (United States)

    Roberts, Bill; Demmert, Cort; Jekauc, Igor; Tiffany, Jason P.

    2004-05-01

    The economics of semiconductor manufacturing have forced process engineers to develop techniques to increase wafer yield. Improvements in process controls and uniformities in all areas of the fab have reduced film thickness variations at the very edge of the wafer surface. This improved uniformity has provided the opportunity to consider decreasing edge exclusions, and now the outermost extents of the wafer must be considered in the yield model and expectations. These changes have increased the requirements on lithography to improve wafer edge printability in areas that previously were not even coated. This has taxed all software and hardware components used in defining the optical focal plane at the wafer edge. We have explored techniques to determine the capabilities of extreme wafer edge printability and the components of the systems that influence this printability. We will present current capabilities and new detection techniques and the influence that the individual hardware and software components have on edge printability. We will show effects of focus sensor designs, wafer layout, utilization of dummy edge fields, the use of non-zero overlay targets and chemical/optical edge bead optimization.

  6. Optically Unraveling the Edge Chirality-Dependent Band Structure and Plasmon Damping in Graphene Edges.

    Science.gov (United States)

    Duan, Jiahua; Chen, Runkun; Cheng, Yuan; Yang, Tianzhong; Zhai, Feng; Dai, Qing; Chen, Jianing

    2018-05-01

    The nontrivial topological origin and pseudospinorial character of electron wavefunctions make edge states possess unusual electronic properties. Twenty years ago, the tight-binding model calculation predicted that zigzag termination of 2D sheets of carbon atoms have peculiar edge states, which show potential application in spintronics and modern information technologies. Although scanning probe microscopy is employed to capture this phenomenon, the experimental demonstration of its optical response remains challenging. Here, the propagating graphene plasmon provides an edge-selective polaritonic probe to directly detect and control the electronic edge state at ambient condition. Compared with armchair, the edge-band structure in the bandgap gives rise to additional optical absorption and strongly absorbed rim at zigzag edge. Furthermore, the optical conductivity is reconstructed and the anisotropic plasmon damping in graphene systems is revealed. The reported approach paves the way for detecting edge-specific phenomena in other van der Waals materials and topological insulators. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Anomalous transport in the tokamak edge

    International Nuclear Information System (INIS)

    Vayakis, G.

    1991-04-01

    The tokamak edge has been studied with arrays of Langmuir and magnetic probes on the DITE and COMPASS-C devices. Measurements of plasma parameters such as density, temperature and radial magnetic field were taken in order to elucidate the character, effect on transport and origin of edge fluctuations. The tokamak edge is a strongly-turbulent environment, with large electrostatic fluctuation levels and broad spectra. The observations, including direct correlation measurements, are consistent with a picture in which the observed magnetic field fluctuations are driven by the perturbations in electrostatic parameters. The propagation characteristics of the turbulence, investigated using digital spectral techniques, appear to be dominated by the variation of the radial electric field, both in limiter and divertor plasmas. A shear layer is formed, associated in each case with the last closed flux surface. In the shear layer, the electrostatic wavenumber spectra are significantly broader. The predictions of a drift wave model (DDGDT) and of a family of models evolving from the rippling mode (RGDT group), are compared with experimental results. RGDT, augmented by impurity radiation effects, is shown to be the most reasonable candidate to explain the nature of the edge turbulence, only failing in its estimate of the wavenumber range. (Author)

  8. Material Discrimination Based on K-edge Characteristics

    Directory of Open Access Journals (Sweden)

    Peng He

    2013-01-01

    Full Text Available Spectral/multienergy CT employing the state-of-the-art energy-discriminative photon-counting detector can identify absorption features in the multiple ranges of photon energies and has the potential to distinguish different materials based on K-edge characteristics. K-edge characteristics involve the sudden attenuation increase in the attenuation profile of a relatively high atomic number material. Hence, spectral CT can utilize material K-edge characteristics (sudden attenuation increase to capture images in available energy bins (levels/windows to distinguish different material components. In this paper, we propose an imaging model based on K-edge characteristics for maximum material discrimination with spectral CT. The wider the energy bin width is, the lower the noise level is, but the poorer the reconstructed image contrast is. Here, we introduce the contrast-to-noise ratio (CNR criterion to optimize the energy bin width after the K-edge jump for the maximum CNR. In the simulation, we analyze the reconstructed image quality in different energy bins and demonstrate that our proposed optimization approach can maximize CNR between target region and background region in reconstructed image.

  9. The Inner Urban Edge

    Science.gov (United States)

    Ferebee, Ann; Carpenter, Edward K.

    1974-01-01

    In this article, renewal of the inner urban edge is discussed. Norfolk (Virginia) is attempting to blur the difference between old and new neighbor hoods through zoning and architectural controls. Cincinnati (Ohio) is developing an environmentally sound hillside design. Reading (Pennsylvania) is utilizing old railyards for greenbelts of hiking and…

  10. Swords with Blunt Edges

    Science.gov (United States)

    Popham, W. James

    2004-01-01

    Many U.S. educators now wonder whether they're teachers or targets. This mentality stems from the specter of their school being sanctioned for failing the state accountability tests mandated under No Child Left Behind (NCLB). According to this author, most of those tests are like blunt-edged swords: They function badly in two directions. While…

  11. Vortex dynamics in superconducting transition edge sensors

    Science.gov (United States)

    Ezaki, S.; Maehata, K.; Iyomoto, N.; Asano, T.; Shinozaki, B.

    2018-02-01

    The temperature dependence of the electrical resistance (R-T) and the current-voltage (I-V) characteristics has been measured and analyzed in a 40 nm thick Ti thin film, which is used as a transition edge sensor (TES). The analyses of the I-V characteristics with the vortex-antivortex pair dissociation model indicate the possible existence of the Berezinskii-Kosterlitz-Thouless (BKT) transition in two-dimensional superconducting Ti thin films. We investigated the noise due to the vortices' flow in TESs. The values of the current noise spectral density in the TESs were estimated by employing the vortex dynamics caused by the BKT transition in the Ti thin films. The estimated values of the current noise spectral density induced by the vortices' flow were in respectable agreement with the values of excess noise experimentally observed in the TESs with Ti/Au bilayer.

  12. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance....

  13. High-resolution molybdenum K-edge X-ray absorption spectroscopy analyzed with time-dependent density functional theory.

    Science.gov (United States)

    Lima, Frederico A; Bjornsson, Ragnar; Weyhermüller, Thomas; Chandrasekaran, Perumalreddy; Glatzel, Pieter; Neese, Frank; DeBeer, Serena

    2013-12-28

    X-ray absorption spectroscopy (XAS) is a widely used experimental technique capable of selectively probing the local structure around an absorbing atomic species in molecules and materials. When applied to heavy elements, however, the quantitative interpretation can be challenging due to the intrinsic spectral broadening arising from the decrease in the core-hole lifetime. In this work we have used high-energy resolution fluorescence detected XAS (HERFD-XAS) to investigate a series of molybdenum complexes. The sharper spectral features obtained by HERFD-XAS measurements enable a clear assignment of the features present in the pre-edge region. Time-dependent density functional theory (TDDFT) has been previously shown to predict K-pre-edge XAS spectra of first row transition metal compounds with a reasonable degree of accuracy. Here we extend this approach to molybdenum K-edge HERFD-XAS and present the necessary calibration. Modern pure and hybrid functionals are utilized and relativistic effects are accounted for using either the Zeroth Order Regular Approximation (ZORA) or the second order Douglas-Kroll-Hess (DKH2) scalar relativistic approximations. We have found that both the predicted energies and intensities are in excellent agreement with experiment, independent of the functional used. The model chosen to account for relativistic effects also has little impact on the calculated spectra. This study provides an important calibration set for future applications of molybdenum HERFD-XAS to complex catalytic systems.

  14. Magnetotransport Properties of Graphene Nanoribbons with Zigzag Edges

    Science.gov (United States)

    Wu, Shuang; Liu, Bing; Shen, Cheng; Li, Si; Huang, Xiaochun; Lu, Xiaobo; Chen, Peng; Wang, Guole; Wang, Duoming; Liao, Mengzhou; Zhang, Jing; Zhang, Tingting; Wang, Shuopei; Yang, Wei; Yang, Rong; Shi, Dongxia; Watanabe, Kenji; Taniguchi, Takashi; Yao, Yugui; Wang, Weihua; Zhang, Guangyu

    2018-05-01

    The determination of the electronic structure by edge geometry is unique to graphene. In theory, an evanescent nonchiral edge state is predicted at the zigzag edges of graphene. Up to now, the approach used to study zigzag-edged graphene has mostly been limited to scanning tunneling microscopy. The transport properties have not been revealed. Recent advances in hydrogen plasma-assisted "top-down" fabrication of zigzag-edged graphene nanoribbons (Z-GNRs) have allowed us to investigate edge-related transport properties. In this Letter, we report the magnetotransport properties of Z-GNRs down to ˜70 nm wide on an h -BN substrate. In the quantum Hall effect regime, a prominent conductance peak is observed at Landau ν =0 , which is absent in GNRs with nonzigzag edges. The conductance peak persists under perpendicular magnetic fields and low temperatures. At a zero magnetic field, a nonlocal voltage signal, evidenced by edge conduction, is detected. These prominent transport features are closely related to the observable density of states at the hydrogen-etched zigzag edge of graphene probed by scanning tunneling spectroscopy, which qualitatively matches the theoretically predicted electronic structure for zigzag-edged graphene. Our study gives important insights for the design of new edge-related electronic devices.

  15. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  16. Left–Right Asymmetry in Spectral Characteristics of Lung Sounds Detected Using a Dual-Channel Auscultation System in Healthy Young Adults

    Science.gov (United States)

    Tsai, Jang-Zern; Chang, Ming-Lang; Yang, Jiun-Yue; Kuo, Dar; Lin, Ching-Hsiung; Kuo, Cheng-Deng

    2017-01-01

    Though lung sounds auscultation is important for the diagnosis and monitoring of lung diseases, the spectral characteristics of lung sounds have not been fully understood. This study compared the spectral characteristics of lung sounds between the right and left lungs and between healthy male and female subjects using a dual-channel auscultation system. Forty-two subjects aged 18–22 years without smoking habits and any known pulmonary diseases participated in this study. The lung sounds were recorded from seven pairs of auscultation sites on the chest wall simultaneously. We found that in four out of seven auscultation pairs, the lung sounds from the left lung had a higher total power (PT) than those from the right lung. The PT of male subjects was higher than that of female ones in most auscultation pairs. The ratio of inspiration power to expiration power (RI/E) of lung sounds from the right lung was greater than that from the left lung at auscultation pairs on the anterior chest wall, while this phenomenon was reversed at auscultation pairs on the posterior chest wall in combined subjects, and similarly in both male and female subjects. Though the frequency corresponding to maximum power density of lung sounds (FMPD) from the left and right lungs was not significantly different, the frequency that equally divided the power spectrum of lung sounds (F50) from the left lung was significantly smaller than that from the right lung at auscultation site on the anterior and lateral chest walls, while it was significantly larger than that of from the right lung at auscultation site on the posterior chest walls. In conclusion, significant differences in the PT, FMPD, F50, and RI/E between the left and right lungs at some auscultation pairs were observed by using a dual-channel auscultation system in this study. Structural differences between the left and the right lungs, between the female and male subjects, and between anterior and posterior lungs might account for the

  17. Left–Right Asymmetry in Spectral Characteristics of Lung Sounds Detected Using a Dual-Channel Auscultation System in Healthy Young Adults

    Directory of Open Access Journals (Sweden)

    Jang-Zern Tsai

    2017-06-01

    Full Text Available Though lung sounds auscultation is important for the diagnosis and monitoring of lung diseases, the spectral characteristics of lung sounds have not been fully understood. This study compared the spectral characteristics of lung sounds between the right and left lungs and between healthy male and female subjects using a dual-channel auscultation system. Forty-two subjects aged 18–22 years without smoking habits and any known pulmonary diseases participated in this study. The lung sounds were recorded from seven pairs of auscultation sites on the chest wall simultaneously. We found that in four out of seven auscultation pairs, the lung sounds from the left lung had a higher total power (PT than those from the right lung. The PT of male subjects was higher than that of female ones in most auscultation pairs. The ratio of inspiration power to expiration power (RI/E of lung sounds from the right lung was greater than that from the left lung at auscultation pairs on the anterior chest wall, while this phenomenon was reversed at auscultation pairs on the posterior chest wall in combined subjects, and similarly in both male and female subjects. Though the frequency corresponding to maximum power density of lung sounds (FMPD from the left and right lungs was not significantly different, the frequency that equally divided the power spectrum of lung sounds (F50 from the left lung was significantly smaller than that from the right lung at auscultation site on the anterior and lateral chest walls, while it was significantly larger than that of from the right lung at auscultation site on the posterior chest walls. In conclusion, significant differences in the PT, FMPD, F50, and RI/E between the left and right lungs at some auscultation pairs were observed by using a dual-channel auscultation system in this study. Structural differences between the left and the right lungs, between the female and male subjects, and between anterior and posterior lungs might

  18. Thermo spectral analysis (TSA) of living human skin by FT-IR -Development of a diagnostic method for the early detection of chronic diseases

    Science.gov (United States)

    Folberth, W.; Heim, G.

    1985-12-01

    A Fourier spectrometer was used in order to measure the spectral emissivity E(k) of human skin in the FIR region k=190-420 cm-1. Three studies on patient groups with defined chronic diseases have been performed: patients with untreated bronchial carcinoma, patients with rheumatic arthritis and patients with chronic renal insufficiency. In comparison with a symptomfree control group all patient groups show significant differences in E(k). As result of a discriminant analysis a separation of 95.7% between carcinoma patients and control persons is possible. The separation quotes between the other groups indicate that patients with malignant neoplasms can be discriminated from other chronically ill persons.

  19. Left-Right Asymmetry in Spectral Characteristics of Lung Sounds Detected Using a Dual-Channel Auscultation System in Healthy Young Adults.

    Science.gov (United States)

    Tsai, Jang-Zern; Chang, Ming-Lang; Yang, Jiun-Yue; Kuo, Dar; Lin, Ching-Hsiung; Kuo, Cheng-Deng

    2017-06-07

    Though lung sounds auscultation is important for the diagnosis and monitoring of lung diseases, the spectral characteristics of lung sounds have not been fully understood. This study compared the spectral characteristics of lung sounds between the right and left lungs and between healthy male and female subjects using a dual-channel auscultation system. Forty-two subjects aged 18-22 years without smoking habits and any known pulmonary diseases participated in this study. The lung sounds were recorded from seven pairs of auscultation sites on the chest wall simultaneously. We found that in four out of seven auscultation pairs, the lung sounds from the left lung had a higher total power (P T ) than those from the right lung. The P T of male subjects was higher than that of female ones in most auscultation pairs. The ratio of inspiration power to expiration power (R I/E ) of lung sounds from the right lung was greater than that from the left lung at auscultation pairs on the anterior chest wall, while this phenomenon was reversed at auscultation pairs on the posterior chest wall in combined subjects, and similarly in both male and female subjects. Though the frequency corresponding to maximum power density of lung sounds (F MPD ) from the left and right lungs was not significantly different, the frequency that equally divided the power spectrum of lung sounds (F 50 ) from the left lung was significantly smaller than that from the right lung at auscultation site on the anterior and lateral chest walls, while it was significantly larger than that of from the right lung at auscultation site on the posterior chest walls. In conclusion, significant differences in the P T , F MPD , F 50 , and R I/E between the left and right lungs at some auscultation pairs were observed by using a dual-channel auscultation system in this study. Structural differences between the left and the right lungs, between the female and male subjects, and between anterior and posterior lungs might

  20. The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

    Directory of Open Access Journals (Sweden)

    Lin Yang

    Full Text Available Frequency-difference electrical impedance tomography (fdEIT reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz. In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

  1. The Frequency Spectral Properties of Electrode-Skin Contact Impedance on Human Head and Its Frequency-Dependent Effects on Frequency-Difference EIT in Stroke Detection from 10Hz to 1MHz.

    Science.gov (United States)

    Yang, Lin; Dai, Meng; Xu, Canhua; Zhang, Ge; Li, Weichen; Fu, Feng; Shi, Xuetao; Dong, Xiuzhen

    2017-01-01

    Frequency-difference electrical impedance tomography (fdEIT) reconstructs frequency-dependent changes of a complex impedance distribution. It has a potential application in acute stroke detection because there are significant differences in impedance spectra between stroke lesions and normal brain tissues. However, fdEIT suffers from the influences of electrode-skin contact impedance since contact impedance varies greatly with frequency. When using fdEIT to detect stroke, it is critical to know the degree of measurement errors or image artifacts caused by contact impedance. To our knowledge, no study has systematically investigated the frequency spectral properties of electrode-skin contact impedance on human head and its frequency-dependent effects on fdEIT used in stroke detection within a wide frequency band (10 Hz-1 MHz). In this study, we first measured and analyzed the frequency spectral properties of electrode-skin contact impedance on 47 human subjects' heads within 10 Hz-1 MHz. Then, we quantified the frequency-dependent effects of contact impedance on fdEIT in stroke detection in terms of the current distribution beneath the electrodes and the contact impedance imbalance between two measuring electrodes. The results showed that the contact impedance at high frequencies (>100 kHz) significantly changed the current distribution beneath the electrode, leading to nonnegligible errors in boundary voltages and artifacts in reconstructed images. The contact impedance imbalance at low frequencies (<1 kHz) also caused significant measurement errors. We conclude that the contact impedance has critical frequency-dependent influences on fdEIT and further studies on reducing such influences are necessary to improve the application of fdEIT in stroke detection.

  2. The SKED: speckle knife edge detector

    International Nuclear Information System (INIS)

    Sharpies, S D; Light, R A; Achamfuo-Yeboah, S O; Clark, M; Somekh, M G

    2014-01-01

    The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device

  3. The SKED: speckle knife edge detector

    Science.gov (United States)

    Sharpies, S. D.; Light, R. A.; Achamfuo-Yeboah, S. O.; Clark, M.; Somekh, M. G.

    2014-06-01

    The knife edge detector—also known as optical beam deflection—is a simple and robust method of detecting ultrasonic waves using a laser. It is particularly suitable for detection of high frequency surface acoustic waves as the response is proportional to variation of the local tilt of the surface. In the case of a specular reflection of the incident laser beam from a smooth surface, any lateral movement of the reflected beam caused by the ultrasonic waves is easily detected by a pair of photodiodes. The major disadvantage of the knife edge detector is that it does not cope well with optically rough surfaces, those that give a speckled reflection. The optical speckles from a rough surface adversely affect the efficiency of the knife edge detector, because 'dark' speckles move synchronously with 'bright' speckles, and their contributions to the ultrasonic signal cancel each other out. We have developed a new self-adapting sensor which can cope with the optical speckles reflected from a rough surface. It is inelegantly called the SKED—speckle knife edge detector—and like its smooth surface namesake it is simple, cheap, compact, and robust. We describe the theory of its operation, and present preliminary experimental results validating the overall concept and the operation of the prototype device.

  4. A BAND SELECTION METHOD FOR SUB-PIXEL TARGET DETECTION IN HYPERSPECTRAL IMAGES BASED ON LABORATORY AND FIELD REFLECTANCE SPECTRAL COMPARISON

    Directory of Open Access Journals (Sweden)

    S. Sharifi hashjin

    2016-06-01

    Full Text Available In recent years, developing target detection algorithms has received growing interest in hyperspectral images. In comparison to the classification field, few studies have been done on dimension reduction or band selection for target detection in hyperspectral images. This study presents a simple method to remove bad bands from the images in a supervised manner for sub-pixel target detection. The proposed method is based on comparing field and laboratory spectra of the target of interest for detecting bad bands. For evaluation, the target detection blind test dataset is used in this study. Experimental results show that the proposed method can improve efficiency of the two well-known target detection methods, ACE and CEM.

  5. ICRF edge modeling

    International Nuclear Information System (INIS)

    1991-01-01

    This report describes the technical progress for the DOE sponsored grant, ''ICRF Edge Modeling.'' An emphasis is placed on the progress since the Technical Progress Report (January 10, 1990) was submitted to the Department of Energy. The design of ICRF antennas for C-Mod and TFTR was investigated during this period. In addition, quasilinear models for electron heating were refined and applied to the design of ICRF antennas. The relevant professional activities sponsored by this grant are given. 4 refs., 11 figs

  6. ICRF edge modeling studies

    Energy Technology Data Exchange (ETDEWEB)

    Lehrman, I.S. (Grumman Corp. Research Center, Princeton, NJ (USA)); Colestock, P.L. (Princeton Univ., NJ (USA). Plasma Physics Lab.)

    1990-04-01

    Theoretical models have been developed, and are currently being refined, to explain the edge plasma-antenna interaction that occurs during ICRF heating. The periodic structure of a Faraday shielded antenna is found to result in strong ponderomotive force in the vicinity of the antenna. A fluid model, which incorporates the ponderomotive force, shows an increase in transport to the Faraday shield. A kinetic model shows that the strong antenna near fields act to increase the energy of deuterons which strike the shield, thereby increasing the sputtering of shield material. Estimates of edge impurity harmonic heating show no significant heating for either in or out-of-phase antenna operation. Additionally, a particle model for electrons near the shield shows that heating results from the parallel electric field associated with the fast wave. A quasilinear model for edge electron heating is presented and compared to the particle calculations. The models' predictions are shown to be consistent with measurements of enhanced transport. (orig.).

  7. Performance of active edge pixel sensors

    Science.gov (United States)

    Bomben, M.; Ducourthial, A.; Bagolini, A.; Boscardin, M.; Bosisio, L.; Calderini, G.; D'Eramo, L.; Giacomini, G.; Marchiori, G.; Zorzi, N.; Rummler, A.; Weingarten, J.

    2017-05-01

    To cope with the High Luminosity LHC harsh conditions, the ATLAS inner tracker has to be upgraded to meet requirements in terms of radiation hardness, pile up and geometrical acceptance. The active edge technology allows to reduce the insensitive area at the border of the sensor thanks to an ion etched trench which avoids the crystal damage produced by the standard mechanical dicing process. Thin planar n-on-p pixel sensors with active edge have been designed and produced by LPNHE and FBK foundry. Two detector module prototypes, consisting of pixel sensors connected to FE-I4B readout chips, have been tested with beams at CERN and DESY. In this paper the performance of these modules are reported. In particular the lateral extension of the detection volume, beyond the pixel region, is investigated and the results show high hit efficiency also at the detector edge, even in presence of guard rings.

  8. Properties of the tokamak edge plasma

    International Nuclear Information System (INIS)

    Wolff, H.

    1988-01-01

    A short review of some features of the edge plasma in limiter tokamaks is given. The limits of the simple one-dimensional scrape-off layer (SOL) model and the relation between the core plasma are discussed. Multifaceted asymmetric radiation from the edge (MARFE) phenomena and detached plasma are closely connected with the particle and energy balance of the SOL. Their occurrence is based on the relation of plasma parameters of the edge plasma to those of the core. Important problems of plasma wall interactions are the detection of the impurity sources and sinks and the study of the impurity transport and shielding. The non-uniform character of plasma wall interactions and their dependence on the discharge performance still renders difficult any theoretical forecast of impurity distribution and transport and calls for better diagnostics. (author)

  9. Smoothness in Binomial Edge Ideals

    Directory of Open Access Journals (Sweden)

    Hamid Damadi

    2016-06-01

    Full Text Available In this paper we study some geometric properties of the algebraic set associated to the binomial edge ideal of a graph. We study the singularity and smoothness of the algebraic set associated to the binomial edge ideal of a graph. Some of these algebraic sets are irreducible and some of them are reducible. If every irreducible component of the algebraic set is smooth we call the graph an edge smooth graph, otherwise it is called an edge singular graph. We show that complete graphs are edge smooth and introduce two conditions such that the graph G is edge singular if and only if it satisfies these conditions. Then, it is shown that cycles and most of trees are edge singular. In addition, it is proved that complete bipartite graphs are edge smooth.

  10. Spectrally-Selective Photonic Structures for PV Applications

    Directory of Open Access Journals (Sweden)

    Benedikt Bläsi

    2010-01-01

    Full Text Available We review several examples of how spectrally-selective photonic structures may be used to improve solar cell systems. Firstly, we introduce different spectrally-selective structures that are based on interference effects. Examples shown include Rugate filter, edge filter and 3D photonic crystals such as artificial opals. In the second part, we discuss several examples of photovoltaic (PV concepts that utilize spectral selectivity such as fluorescence collectors, upconversion systems, spectrum splitting concepts and the intermediate reflector concept. The potential of spectrally selective filters in the context of solar cells is discussed.

  11. The Edge Detectors Suitable for Retinal OCT Image Segmentation

    Directory of Open Access Journals (Sweden)

    Su Luo

    2017-01-01

    Full Text Available Retinal layer thickness measurement offers important information for reliable diagnosis of retinal diseases and for the evaluation of disease development and medical treatment responses. This task critically depends on the accurate edge detection of the retinal layers in OCT images. Here, we intended to search for the most suitable edge detectors for the retinal OCT image segmentation task. The three most promising edge detection algorithms were identified in the related literature: Canny edge detector, the two-pass method, and the EdgeFlow technique. The quantitative evaluation results show that the two-pass method outperforms consistently the Canny detector and the EdgeFlow technique in delineating the retinal layer boundaries in the OCT images. In addition, the mean localization deviation metrics show that the two-pass method caused the smallest edge shifting problem. These findings suggest that the two-pass method is the best among the three algorithms for detecting retinal layer boundaries. The overall better performance of Canny and two-pass methods over EdgeFlow technique implies that the OCT images contain more intensity gradient information than texture changes along the retinal layer boundaries. The results will guide our future efforts in the quantitative analysis of retinal OCT images for the effective use of OCT technologies in the field of ophthalmology.

  12. Organic conjugated small molecule materials based optical probe for rapid, colorimetric and UV-vis spectral detection of phosphorylated protein in placental tissue.

    Science.gov (United States)

    Wang, Yanfang; Yang, Na; Liu, Yi

    2018-04-05

    A novel organic small molecule with D-Pi-A structure was prepared, which was found to be a promising colorimetric and ratiometric UV-vis spetral probe for detection of phosphorylated proteins with the help of tetravalent zirconium ion. Such optical probe based on chromophore WYF-1 shows a rapid response (within 10s) and high selectivity and sensitivity for phosphorylated proteins, giving distinct colorimetric and ratiometric UV-vis changes at 720 and 560nm. The detection limit for phosphorylated proteins was estimated to be 100nM. In addition, detection of phosphorylated proteins in placental tissue samples with this probe was successfully applied, which indicates that this probe holds great potential for phosphorylated proteins detection. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Intensity Conserving Spectral Fitting

    Science.gov (United States)

    Klimchuk, J. A.; Patsourakos, S.; Tripathi, D.

    2015-01-01

    The detailed shapes of spectral line profiles provide valuable information about the emitting plasma, especially when the plasma contains an unresolved mixture of velocities, temperatures, and densities. As a result of finite spectral resolution, the intensity measured by a spectrometer is the average intensity across a wavelength bin of non-zero size. It is assigned to the wavelength position at the center of the bin. However, the actual intensity at that discrete position will be different if the profile is curved, as it invariably is. Standard fitting routines (spline, Gaussian, etc.) do not account for this difference, and this can result in significant errors when making sensitive measurements. Detection of asymmetries in solar coronal emission lines is one example. Removal of line blends is another. We have developed an iterative procedure that corrects for this effect. It can be used with any fitting function, but we employ a cubic spline in a new analysis routine called Intensity Conserving Spline Interpolation (ICSI). As the name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.

  14. Competing edge networks

    Science.gov (United States)

    Parsons, Mark; Grindrod, Peter

    2012-06-01

    We introduce a model for a pair of nonlinear evolving networks, defined over a common set of vertices, subject to edgewise competition. Each network may grow new edges spontaneously or through triad closure. Both networks inhibit the other's growth and encourage the other's demise. These nonlinear stochastic competition equations yield to a mean field analysis resulting in a nonlinear deterministic system. There may be multiple equilibria; and bifurcations of different types are shown to occur within a reduced parameter space. This situation models competitive communication networks such as BlackBerry Messenger displacing SMS; or instant messaging displacing emails.

  15. Carbon K-edge spectra of carbonate minerals.

    Science.gov (United States)

    Brandes, Jay A; Wirick, Sue; Jacobsen, Chris

    2010-09-01

    Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.

  16. Carbon K-edge Spectra of Carbonate Minerals

    Energy Technology Data Exchange (ETDEWEB)

    Brandes, J.; Wirick, S; Jacobsen, C

    2010-01-01

    Carbon K-edge X-ray spectroscopy has been applied to the study of a wide range of organic samples, from polymers and coals to interstellar dust particles. Identification of carbonaceous materials within these samples is accomplished by the pattern of resonances in the 280-320 eV energy region. Carbonate minerals are often encountered in the study of natural samples, and have been identified by a distinctive resonance at 290.3 eV. Here C K-edge and Ca L-edge spectra from a range of carbonate minerals are presented. Although all carbonates exhibit a sharp 290 eV resonance, both the precise position of this resonance and the positions of other resonances vary among minerals. The relative strengths of the different carbonate resonances also vary with crystal orientation to the linearly polarized X-ray beam. Intriguingly, several carbonate minerals also exhibit a strong 288.6 eV resonance, consistent with the position of a carbonyl resonance rather than carbonate. Calcite and aragonite, although indistinguishable spectrally at the C K-edge, exhibited significantly different spectra at the Ca L-edge. The distinctive spectral fingerprints of carbonates provide an identification tool, allowing for the examination of such processes as carbon sequestration in minerals, Mn substitution in marine calcium carbonates (dolomitization) and serpentinization of basalts.

  17. Spectral evolution of galaxies: current views

    International Nuclear Information System (INIS)

    Bruzual, A.G.

    1985-01-01

    A summary of current views on the interpretation of the various evolutionary tests aimed at detecting spectral evolution in galaxies is presented. It is concluded that the evolution taking place in known galaxy samples is a slow process (perhaps consistent with no evolution at all), and that the early phases of rapid spectral evolution in early-type galaxies have not yet been detected. (author)

  18. Degenerate band edge laser

    Science.gov (United States)

    Veysi, Mehdi; Othman, Mohamed A. K.; Figotin, Alexander; Capolino, Filippo

    2018-05-01

    We propose a class of lasers based on a fourth-order exceptional point of degeneracy (EPD) referred to as the degenerate band edge (DBE). EPDs have been found in parity-time-symmetric photonic structures that require loss and/or gain; here we show that the DBE is a different kind of EPD since it occurs in periodic structures that are lossless and gainless. Because of this property, a small level of gain is sufficient to induce single-frequency lasing based on a synchronous operation of four degenerate Floquet-Bloch eigenwaves. This lasing scheme constitutes a light-matter interaction mechanism that leads also to a unique scaling law of the laser threshold with the inverse of the fifth power of the laser-cavity length. The DBE laser has the lowest lasing threshold in comparison to a regular band edge laser and to a conventional laser in cavities with the same loaded quality (Q ) factor and length. In particular, even without mirror reflectors the DBE laser exhibits a lasing threshold which is an order of magnitude lower than that of a uniform cavity laser of the same length and with very high mirror reflectivity. Importantly, this novel DBE lasing regime enforces mode selectivity and coherent single-frequency operation even for pumping rates well beyond the lasing threshold, in contrast to the multifrequency nature of conventional uniform cavity lasers.

  19. Edge turbulence and transport: Text and ATF modeling

    International Nuclear Information System (INIS)

    Ritz, C.P.; Rhodes, T.L.; Lin, H.; Rowan, W.L.; Bengtson, R.; Wootton, A.J.; Diamond, P.H.; Ware, A.S.; Thayer, D.R.

    1990-01-01

    We present experimental results on edge turbulence and transport from the tokamak TEXT and the torsatron ATF. The measured electrostatic fluctuations can explain the edge transport of particles and energy. Certain drive (radiation) and stabilizing (velocity shear) terms are suggested by the results. The experimental fluctuation levels and spectral widths can be reproduced by considering the nonlinear evolution of the reduced MHD equations, incorporating a thermal drive from line radiation. In the tokamak limit (with toroidal electric field) the model corresponds to the resistivity gradient mode, while in the currentless torsatron or stellarator limit it corresponds to a thermally driven drift wave

  20. Radiographic information theory: correction for x-ray spectral distribution

    International Nuclear Information System (INIS)

    Brodie, I.; Gutcheck, R.A.

    1983-01-01

    A more complete computational method is developed to account for the effect of the spectral distribution of the incident x-ray fluence on the minimum exposure required to record a specified information set in a diagnostic radiograph. It is shown that an earlier, less rigorous, but simpler computational technique does not introduce serious errors provided that both a good estimate of the mean energy per photon can be made and the detector does not contain an absorption edge in the spectral range. Also shown is that to a first approximation, it is immaterial whether the detecting surface counts the number of photons incident from each pixel or measures the energy incident on each pixel. A previous result is confirmed that, for mammography, the present methods of processing data from the detector utilize only a few percent of the incident information, suggesting that techniques can be developed for obtaining mammograms at substantially lower doses than those presently used. When used with film-screen combinations, x-ray tubes with tungsten anodes should require substantially lower exposures than devices using molybdenum anodes, when both are operated at their optimal voltage

  1. Study on spectral parameters and the support vector machine in surface enhanced Raman spectroscopy of serum for the detection of colon cancer

    International Nuclear Information System (INIS)

    Li, Xiaozhou; Yang, Tianyue; Yao, Jun; Wang, Deli; Li, Siqi; Song, Youtao; Ding, Jianhua

    2015-01-01

    Surface enhanced Raman spectroscopy (SERS) has been recognized as an effective tool for the analysis of tissue samples and biofluids. In this work, a total of 27 spectral parameters were chosen and compared using SERS. Four parameters with the highest prediction ability were selected for further support vector machine (SVM) analysis. As a comparison, principal component analysis (PCA) was used on the same dataset for feature extraction. SVM was used with the above two data reduction methods separately to differentiate colon cancer and the control groups. Serum taken from 52 colon cancer patients and 60 healthy volunteers were collected and tested by SERS. The accuracy for Parameter-SVM was 95.0%, the sensitivity was 96.2%, and the specificity was 95.5%, which was much higher than the results using only one parameter, while for PCA-SVM, the results are 93.3%, 92.3%, and 92.9%, respectively. These results demonstrate that the SERS analysis method can be used to identify serum differences between colon cancer patients and normal people. (letter)

  2. Determination of the spectral dependence of reduced scattering and quantitative second-harmonic generation imaging for detection of fibrillary changes in ovarian cancer

    Science.gov (United States)

    Campbell, Kirby R.; Tilbury, Karissa B.; Campagnola, Paul J.

    2015-03-01

    Here, we examine ovarian cancer extracellular matrix (ECM) modification by measuring the wavelength dependence of optical scattering measurements and quantitative second-harmonic generation (SHG) imaging metrics in the range of 800-1100 nm in order to determine fibrillary changes in ex vivo normal ovary, type I, and type II ovarian cancer. Mass fractals of the collagen fiber structure is analyzed based on a power law correlation function using spectral dependence measurements of the reduced scattering coefficient μs' where the mass fractal dimension is related to the power. Values of μs' are measured using independent methods of determining the values of μs and g by on-axis attenuation measurements using the Beer-Lambert Law and by fitting the angular distribution of scattering to the Henyey-Greenstein phase function, respectively. Quantitativespectral SHG imaging on the same tissues determines FSHG/BSHG creation ratios related to size and harmonophore distributions. Both techniques probe fibril packing order, but the optical scattering probes structures of sizes from about 50-2000 nm where SHG imaging - although only able to resolve individual fibers - builds contrast from the assembly of fibrils. Our findings suggest that type I ovarian tumor structure has the most ordered collagen fibers followed by normal ovary then type II tumors showing the least order.

  3. Spectral and angle dependent emission of solar fluorescence collectors

    Energy Technology Data Exchange (ETDEWEB)

    Straeter, Hendrik; Knabe, Sebastian; Bauer, Gottfried H. [Institute of Physics, Carl von Ossietzky University Oldenburg, D-26111 Oldenburg (Germany)

    2011-07-01

    Fluorescence collectors (FCs) provide the option for concentration and simultaneous spectral selection of solar photons of direct or diffuse light. The energetic and commercial benefit of these systems depend on the yield of the conversion of solar photons into luminescence photons and on the efficiency of their respective conductance to the edges of the FC where they are coupled into appropriate solar cells. For the characterization of the performance of FCs and the identification of losses, we have performed angle and spectrally resolved measurements of fluorescence photons from FC with two different types of optical designs, a PMMA substrate with homogeneous depth dependent dye concentration and a novel type of FC, which consist of a transparent substrate with a thin overlayer containing the absorbing and emitting dye. We have recorded the edge fluorescence when illuminating the entire FC surface laterally homogeneously, as well as for slit-like excitation on the front surface with variation of the distance of the illuminated slit from the edge. We compare the experimental fluorescence results with a 2-dimensional ray-tracing approach and verify the spectral and angle dependent edge emission. Moreover we illuminate the FC with long wavelength photons which are not absorbed and conclude, again from angle dependent and spectrally resolved edge emission, on scattering losses at surfaces and in the bulk.

  4. Active probing of plasma edge turbulence and feedback studies on the Texas Experimental Tokamak (TEXT)

    International Nuclear Information System (INIS)

    Uckan, T.; Richards, B.; Bengtson, R.D.

    1993-01-01

    The edge fluctuations play a critical role in the overall tokamak confinement. Experiments on TEXT show that electrostatic fluctuations in the edge plasma are the dominant mechanism for energy and particle transport. The basic mechanisms responsible for the edge turbulence are the subject of ongoing research in fusion devices. To understand the driving forces responsible for edge fluctuations, a novel experiment is underway on TEXT to actively modify the turbulence at the plasma edge by launching waves using electrostatic probes in the shadow of the limiter. This technique permits active probing of the spectral properties of the edge turbulence. This new approach to the study of edge fluctuations can provide more insight into the basic dynamics of the turbulence and may, in turn, enable detailed comparison with the theory. These experiments, which rely on the use of oscillating electric fields at the plasma edge, complement edge fluctuation control studies that are presently limited to the use of applied dc biasing to influence the edge electric field profile. These experiments have been extended to control of the edge plasma fluctuation level, using feedback to explore its effects on the edge turbulence characteristics as well as on confinement. (author) 8 refs., 7 figs

  5. Active probing of plasma edge turbulence and feedback studies on the Texas Experimental Tokamak (TEXT)

    International Nuclear Information System (INIS)

    Uckan, T.; Carreras, B.A.; Richards, B.; Bengtson, R.D.; Crockett, D.B.; Gentle, K.W.; Li, G.X.; Hurwitz, P.D.; Rowan, W.L.; Tsui, H.Y.W.; Wootton, A.J.

    1993-01-01

    The edge fluctuations play a critical role in the overall tokamak confinement. Experiments on TEXT show that electrostatic fluctuations in the edge plasma are the dominant mechanism for energy and particle transport. The basic mechanisms responsible for the edge turbulence are the subject of ongoing research in fusion devices. To understand the driving forces responsible for edge fluctuations, a novel experiment is underway on TEXT to actively modify the turbulence at the plasma edge by launching waves using electrostatic probes in the shadow of the limiter. This technique permits active probing of the spectral properties of the edge turbulence. This new approach to the study of edge fluctuations can provide more insight into the basic dynamics of the turbulence and may, in turn, enable detailed comparison with the theory. These experiments, which rely on the use of oscillating electric fields at the plasma edge, complement edge fluctuation control studies that are presently limited to the use of applied dc biasing to influence the edge electric field profile. These experiments have been extended to control of the edge plasma fluctuation level, using feedback to explore its effects on the edge turbulence characteristics as well as on confinement

  6. Separability Analysis of Sentinel-2A Multi-Spectral Instrument (MSI Data for Burned Area Discrimination

    Directory of Open Access Journals (Sweden)

    Haiyan Huang

    2016-10-01

    Full Text Available Biomass burning is a global phenomenon and systematic burned area mapping is of increasing importance for science and applications. With high spatial resolution and novelty in band design, the recently launched Sentinel-2A satellite provides a new opportunity for moderate spatial resolution burned area mapping. This study examines the performance of the Sentinel-2A Multi Spectral Instrument (MSI bands and derived spectral indices to differentiate between unburned and burned areas. For this purpose, five pairs of pre-fire and post-fire top of atmosphere (TOA reflectance and atmospherically corrected (surface reflectance images were studied. The pixel values of locations that were unburned in the first image and burned in the second image, as well as the values of locations that were unburned in both images which served as a control, were compared and the discrimination of individual bands and spectral indices were evaluated using parametric (transformed divergence and non-parametric (decision tree approaches. Based on the results, the most suitable MSI bands to detect burned areas are the 20 m near-infrared, short wave infrared and red-edge bands, while the performance of the spectral indices varied with location. The atmospheric correction only significantly influenced the separability of the visible wavelength bands. The results provide insights that are useful for developing Sentinel-2 burned area mapping algorithms.

  7. Wisps in the outer edge of the Keeler Gap

    Science.gov (United States)

    Tiscareno, Matthew S.; Arnault, Ethan G.

    2015-11-01

    Superposed upon the relatively smooth outer edge of the Keeler Gap are a system of "wisps," which appear to be ring material protruding inward into the gap, usually with a sharp trailing edge and a smooth gradation back to the background edge location on the leading side (Porco et al. 2005, Science). The radial amplitude of wisps is usually 0.5 to 1 km, and their azimuthal extent is approximately a degree of longitude (~2400 km). Wisps are likely caused by an interplay between Daphnis (and perhaps other moons) and embedded moonlets within the ring, though the details remain unclear.Aside from the wisps, the Keeler Gap outer edge is the only one of the five sharp edges in the outer part of Saturn's A ring that is reasonably smooth in appearance (Tiscareno et al. 2005, DPS), with occultations indicating residuals less than 1 km upon a possibly non-zero eccentricity (R.G. French, personal communication, 2014). The other four (the inner and outer edges of the Encke Gap, the inner edge of the Keeler Gap, and the outer edge of the A ring itself) are characterized by wavy structure at moderate to high spatial frequencies, with amplitudes ranging from 2 to 30 km (Tiscareno et al. 2005, DPS).We will present a catalogue of wisp detections in Cassini images. We carry out repeated gaussian fits of the radial edge location in order to characterize edge structure and visually scan those fitted edges in order to detect wisps. With extensive coverage in longitude and in time, we will report on how wisps evolve and move, both within an orbit period and on longer timescales. We will also report on the frequency and interpretation of wisps that deviate from the standard morphology. We will discuss the implications of our results for the origin and nature of wisps, and for the larger picture of how masses interact within Saturn's rings.

  8. Multi-scale Regions from Edge Fragments

    DEFF Research Database (Denmark)

    Kazmi, Wajahat; Andersen, Hans Jørgen

    2014-01-01

    In this article we introduce a novel method for detecting multi-scale salient regions around edges using a graph based image compression algorithm. Images are recursively decomposed into triangles arranged into a binary tree using linear interpolation. The entropy of any local region of the image......), their performance is comparable to SIFT (Lowe, 2004).We also show that when they are used together with MSERs (Matas et al., 2002), the performance of MSERs is boosted....

  9. Spectral gamuts and spectral gamut mapping

    Science.gov (United States)

    Rosen, Mitchell R.; Derhak, Maxim W.

    2006-01-01

    All imaging devices have two gamuts: the stimulus gamut and the response gamut. The response gamut of a print engine is typically described in CIE colorimetry units, a system derived to quantify human color response. More fundamental than colorimetric gamuts are spectral gamuts, based on radiance, reflectance or transmittance units. Spectral gamuts depend on the physics of light or on how materials interact with light and do not involve the human's photoreceptor integration or brain processing. Methods for visualizing a spectral gamut raise challenges as do considerations of how to utilize such a data-set for producing superior color reproductions. Recent work has described a transformation of spectra reduced to 6-dimensions called LabPQR. LabPQR was designed as a hybrid space with three explicit colorimetric axes and three additional spectral reconstruction axes. In this paper spectral gamuts are discussed making use of LabPQR. Also, spectral gamut mapping is considered in light of the colorimetric-spectral duality of the LabPQR space.

  10. Cheating on the edge.

    Directory of Open Access Journals (Sweden)

    Lee Alan Dugatkin

    2008-07-01

    Full Text Available We present the results of an individual agent-based model of antibiotic resistance in bacteria. Our model examines antibiotic resistance when two strategies exist: "producers"--who secrete a substance that breaks down antibiotics--and nonproducers ("cheats" who do not secrete, or carry the machinery associated with secretion. The model allows for populations of up to 10,000, in which bacteria are affected by their nearest neighbors, and we assume cheaters die when there are no producers in their neighborhood. Each of 10,000 slots on our grid (a torus could be occupied by a producer or a nonproducer, or could (temporarily be unoccupied. The most surprising and dramatic result we uncovered is that when producers and nonproducers coexist at equilibrium, nonproducers are almost always found on the edges of clusters of producers.

  11. Challenges in edge modeling

    International Nuclear Information System (INIS)

    Schneider, R.

    2007-01-01

    Fluid models like B2, UEDGE or EDGE2D are the working horses for scrape-off layer physics, both for design and experimental support. The concept of a numerical tokamak, aiming at a predictive code for ITER, triggers the need to re-assess the available tools and their necessary extensions. These additional physics issues will be summarized from a personal point-of-view. Depending on the specific problem, several complexity levels of scrape-off layer models will be needed. Therefore, a hierarchy of tools is necessary, which will be discussed. Furthermore, the experience existing in other scientific fields with multi-scale problems and modeling should be used. Here, the coupling of different length and time scales are in particular of interest for fusion problems. (author)

  12. Edge remap for solids

    Energy Technology Data Exchange (ETDEWEB)

    Kamm, James R.; Love, Edward; Robinson, Allen C; Young, Joseph G.; Ridzal, Denis

    2013-12-01

    We review the edge element formulation for describing the kinematics of hyperelastic solids. This approach is used to frame the problem of remapping the inverse deformation gradient for Arbitrary Lagrangian-Eulerian (ALE) simulations of solid dynamics. For hyperelastic materials, the stress state is completely determined by the deformation gradient, so remapping this quantity effectively updates the stress state of the material. A method, inspired by the constrained transport remap in electromagnetics, is reviewed, according to which the zero-curl constraint on the inverse deformation gradient is implicitly satisfied. Open issues related to the accuracy of this approach are identified. An optimization-based approach is implemented to enforce positivity of the determinant of the deformation gradient. The efficacy of this approach is illustrated with numerical examples.

  13. Playing on the edge

    DEFF Research Database (Denmark)

    Cermak-Sassenrath, Daniel

    2018-01-01

    and specific ways. For instance, gambling for money, party and drinking games, professional play and show sports, art installations, violent and military propaganda computer games, pervasive/mobile gaming, live-action role playing, festivals, performances, and games such as Ghosting and Planking. It is argued......Everything gets more interesting, challenging, or intense the closer it gets to the edge, and so does play. How edgy can play become and still be play? Based on Huizinga’s notion of play, this chapter discusses how a wide range of playful activities pushes the boundaries of play in different...... that in concert with a number of characteristics that mark an activity as play, play is essentially a subjective perspective and individual decision of the player. Huizinga calls this attitude the play spirit, which informs a player’s actions and is in turn sustained by them. Edgy digital or mobile games do...

  14. Competing edge networks

    International Nuclear Information System (INIS)

    Parsons, Mark; Grindrod, Peter

    2012-01-01

    We introduce a model for a pair of nonlinear evolving networks, defined over a common set of vertices, subject to edgewise competition. Each network may grow new edges spontaneously or through triad closure. Both networks inhibit the other's growth and encourage the other's demise. These nonlinear stochastic competition equations yield to a mean field analysis resulting in a nonlinear deterministic system. There may be multiple equilibria; and bifurcations of different types are shown to occur within a reduced parameter space. This situation models competitive communication networks such as BlackBerry Messenger displacing SMS; or instant messaging displacing emails. -- Highlights: ► A model for edgewise-competing evolving network pairs is introduced. ► Defined competition equations yield to a mean field analysis. ► Multiple equilibrium states and different bifurcation types can occur. ► The system is sensitive to sparse initial conditions and near unstable equilibriums.

  15. SPECTRAL SMILE CORRECTION IN CRISM HYPERSPECTRAL IMAGES

    Science.gov (United States)

    Ceamanos, X.; Doute, S.

    2009-12-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is affected by a common artifact in "push-broom" sensors, the so-called "spectral smile". As a consequence, both central wavelength and spectral width of the spectral response vary along the across-track dimension, thus giving rise to a shifting and smoothing of spectra (see Fig. 1 (left)). In fact, both effects are greater for spectra on the edges, while they are minimum for data acquired by central detectors, the so-called "sweet spot". The prior artifacts become particularly critical for Martian observations which contain steep spectra such as CO2 ice-rich polar images. Fig. 1 (right) shows the horizontal brightness gradient which appears in every band corresponding to a steep portion of spectra. The correction of CRISM spectral smile is addressed using a two-step method which aims at modifying data sensibly in order to mimic the optimal CRISM response. First, all spectra, which are previously interpolated by cubic splines, are resampled to the "sweet spot" wavelengths in order to overcome the spectra shift. Secondly, the non-uniform spectral width is overcome by mimicking an increase of spectral resolution thanks to a spectral sharpening. In order to minimize noise, only bands particularly suffering from smile are selected. First, bands corresponding to the outliers of the Minimum Noise Transformation (MNF) eigenvector, which corresponds to the MNF band related to smile (MNF-smile), are selected. Then, a spectral neighborhood Θi, which takes into account the local spectral convexity or concavity, is defined for every selected band in order to maximize spectral shape preservation. The proposed sharpening technique takes into account both the instrument parameters and the observed spectra. First, every reflectance value belonging to a Θi is reevaluated by a sharpening which depends on a ratio of the spectral width of the current detector and the "sweet spot" one. Then, the optimal degree of

  16. Characterizing the 21-cm Signal from Neutral Hydrogen in the IGM at Redshifts 27>z>6 with EDGES

    Science.gov (United States)

    Monsalve, Raul A.; Rogers, Alan E. E.; Bowman, Judd D.; Mozdzen, Thomas J.; Mahesh, Nivedita

    2018-01-01

    Understanding the period when the first stars formed and ionized the InterGalactic Medium (IGM) during the Epoch of Reionization (EoR) represents one of the main objectives of modern cosmology. The Experiment to Detect the Global EoR Signature (EDGES) strives to characterize this period by measuring, for the first time, the all-sky spectrum of the 21-cm signal produced by neutral hydrogen in the IGM at redshifts 27>z>6. In this talk I will describe recent EDGES constraints for the 21-cm signal. Specifically, with measurements from the EDGES High-Band instrument in the range 90-190 MHz, we rule out traditional Tanh models for the epoch of reionization with durations of up to dz=1 over the redshift range 14>z>7. We also rule out a wide range of phenomenological and physically-motivated 21-cm models that contain a large absorption feature in this redshift range, produced by the complex interaction between UV and X-ray radiation from the first sources and the neutral hydrogen in the IGM. Finally, I will describe our efforts to detect the 21-cm signal in the range 27>z>13 with two Low-Band instruments that have observed over 50-100 MHz since 2015. These instruments implement refined calibration techniques and lessons learned from previous generations of EDGES, and have achieved a level of systematic uncertainty low enough to enable detection. I will present Low-Band analysis results, including a variety of cross-checks performed to discriminate between residual instrumental effects and spectral structure that is intrinsic to the sky. I will conclude by describing the preparation of the next observational campaign with upgraded instrumentation.

  17. Detecting Molecular Features of Spectra Mainly Associated with Structural and Non-Structural Carbohydrates in Co-Products from BioEthanol Production Using DRIFT with Uni- and Multivariate Molecular Spectral Analyses

    Science.gov (United States)

    Yu, Peiqiang; Damiran, Daalkhaijav; Azarfar, Arash; Niu, Zhiyuan

    2011-01-01

    The objective of this study was to use DRIFT spectroscopy with uni- and multivariate molecular spectral analyses as a novel approach to detect molecular features of spectra mainly associated with carbohydrate in the co-products (wheat DDGS, corn DDGS, blend DDGS) from bioethanol processing in comparison with original feedstock (wheat (Triticum), corn (Zea mays)). The carbohydrates related molecular spectral bands included: A_Cell (structural carbohydrates, peaks area region and baseline: ca. 1485–1188 cm−1), A_1240 (structural carbohydrates, peak area centered at ca. 1240 cm−1 with region and baseline: ca. 1292–1198 cm−1), A_CHO (total carbohydrates, peaks region and baseline: ca. 1187–950 cm−1), A_928 (non-structural carbohydrates, peak area centered at ca. 928 cm−1 with region and baseline: ca. 952–910 cm−1), A_860 (non-structural carbohydrates, peak area centered at ca. 860 cm−1 with region and baseline: ca. 880–827 cm−1), H_1415 (structural carbohydrate, peak height centered at ca. 1415 cm−1 with baseline: ca. 1485–1188 cm−1), H_1370 (structural carbohydrate, peak height at ca. 1370 cm−1 with a baseline: ca. 1485–1188 cm−1). The study shows that the grains had lower spectral intensity (KM Unit) of the cellulosic compounds of A_1240 (8.5 vs. 36.6, P carbohydrate of A_928 (17.3 vs. 2.0) and A_860 (20.7 vs. 7.6) than their co-products from bioethanol processing. There were no differences (P > 0.05) in the peak area intensities of A_Cell (structural CHO) at 1292–1198 cm−1 and A_CHO (total CHO) at 1187–950 cm−1 with average molecular infrared intensity KM unit of 226.8 and 508.1, respectively. There were no differences (P > 0.05) in the peak height intensities of H_1415 and H_1370 (structural CHOs) with average intensities 1.35 and 1.15, respectively. The multivariate molecular spectral analyses were able to discriminate and classify between the corn and corn DDGS molecular spectra, but not wheat and wheat DDGS. This

  18. Advanced Trailing Edge Blowing Concepts for Fan Noise Control

    Directory of Open Access Journals (Sweden)

    Cezar RIZEA

    2012-03-01

    Full Text Available This study documents trailing edge blowing research performed to reduce rotor / stator interaction noise in turbofan engines. The existing technique of filling every velocity deficit requires a large amount of air and is therefore impractical. The purpose of this research is to investigate new blowing configurations in order to achieve noise reduction with lesser amounts of air. Using the new configurations air is not injected into every fan blade, but is instead varied circumferentially. For example, blowing air may be applied to alternating fan blades. This type of blowing configuration both reduces the amount of air used and changes the spectral shape of the tonal interaction noise. The original tones at the blade passing frequency and its harmonics are reduced and new tones are introduced between them. This change in the tonal spectral shape increases the performance of acoustic liners used in conjunction with trailing edge blowing.

  19. Edge computing technologies for Internet of Things: a primer

    Directory of Open Access Journals (Sweden)

    Yuan Ai

    2018-04-01

    Full Text Available With the rapid development of mobile internet and Internet of Things applications, the conventional centralized cloud computing is encountering severe challenges, such as high latency, low Spectral Efficiency (SE, and non-adaptive machine type of communication. Motivated to solve these challenges, a new technology is driving a trend that shifts the function of centralized cloud computing to edge devices of networks. Several edge computing technologies originating from different backgrounds to decrease latency, improve SE, and support the massive machine type of communication have been emerging. This paper comprehensively presents a tutorial on three typical edge computing technologies, namely mobile edge computing, cloudlets, and fog computing. In particular, the standardization efforts, principles, architectures, and applications of these three technologies are summarized and compared. From the viewpoint of radio access network, the differences between mobile edge computing and fog computing are highlighted, and the characteristics of fog computing-based radio access network are discussed. Finally, open issues and future research directions are identified as well. Keywords: Internet of Things (IoT, Mobile edge computing, Cloudlets, Fog computing

  20. WIDEFIELD SPECTRAL-DOMAIN OPTICAL COHERENCE TOMOGRAPHY IMAGING OF PERIPHERAL ROUND RETINAL HOLES WITH OR WITHOUT RETINAL DETACHMENT.

    Science.gov (United States)

    Casswell, Edward J; Abou Ltaif, Sleiman; Carr, Thomas; Keane, Pearse A; Charteris, David G; Wickham, Louisa

    2018-03-02

    To describe the widefield spectral-domain optical coherence tomography features of peripheral round retinal holes, with or without associated retinal detachment (RD). Retrospective, observational study of 28 eyes with peripheral round retinal holes, with and without RD. Patients underwent imaging with a widefield 50-degree spectral-domain optical coherence tomography (Heidelberg Engineering, Germany) and Optos ultra-widefield imaging systems (Optos, United Kingdom). Vitreous attachment at the site of the retinal hole was detected in 27/28 (96.4%) cases. Cases were split into three groups: RHs with RD (n = 12); RHs with subretinal fluid (n = 5), and flat RHs (n = 11), with minimal or no subretinal fluid. 91.6% retinal holes associated with subretinal fluid or RD had vitreous attachment at the site of the hole. Eighty percent had vitreous attachment at both edges of the retinal hole, in a U-shape configuration, which appeared to exert traction. By contrast, flat retinal holes had visible vitreous attachment only at one edge of the retinal hole in 45.4%. Vitreous attachment was commonly seen at the site of round retinal holes. Vitreous attachment at both edges of the retinal hole in a U-shape configuration was more commonly seen at holes associated with subretinal fluid or RD.

  1. Ionized gas at the edge of the central molecular zone

    Science.gov (United States)

    Langer, W. D.; Goldsmith, P. F.; Pineda, J. L.; Velusamy, T.; Requena-Torres, M. A.; Wiesemeyer, H.

    2015-04-01

    Context. The edge of the central molecular zone (CMZ) is the location where massive dense molecular clouds with large internal velocity dispersions transition to the surrounding more quiescent and lower CO emissivity region of the Galaxy. Little is known about the ionized gas surrounding the molecular clouds and in the transition region. Aims: We determine the properties of the ionized gas at the edge of the CMZ near Sgr E using observations of N+ and C+. Methods: We observed a small portion of the edge of the CMZ near Sgr E with spectrally resolved [C ii] 158 μm and [N ii] 205 μm fine structure lines at six positions with the GREAT instrument on SOFIA and in [C ii] using Herschel HIFI on-the-fly strip maps. We use the [N ii] spectra along with a radiative transfer model to calculate the electron density of the gas and the [C ii] maps to illuminate the morphology of the ionized gas and model the column density of CO-dark H2. Results: We detect two [C ii] and [N ii] velocity components, one along the line of sight to a CO molecular cloud at - 207 km s-1 associated with Sgr E and the other at -174 km s-1 outside the edge of another CO cloud. From the [N ii] emission we find that the average electron density is in the range of ~5 to 21 cm-3 for these features. This electron density is much higher than that of the disk's warm ionized medium, but is consistent with densities determined for bright diffuse H ii nebula. The column density of the CO-dark H2 layer in the -207 km s-1 cloud is ~1-2 × 1021 cm-2 in agreement with theoretical models. The CMZ extends further out in Galactic radius by ~7 to 14 pc in ionized gas than it does in molecular gas traced by CO. Conclusions: The edge of the CMZ likely contains dense hot ionized gas surrounding the neutral molecular material. The high fractional abundance of N+ and high electron density require an intense EUV field with a photon flux of order 106 to 107 photons cm-2 s-1, and/or efficient proton charge exchange with

  2. Cutting Edge Localisation in an Edge Profile Milling Head

    NARCIS (Netherlands)

    Fernandez Robles, Laura; Azzopardi, George; Alegre, Enrique; Petkov, Nicolai

    2015-01-01

    Wear evaluation of cutting tools is a key issue for prolonging their lifetime and ensuring high quality of products. In this paper, we present a method for the effective localisation of cutting edges of inserts in digital images of an edge profile milling head. We introduce a new image data set of

  3. Cell-Edge Multi-User Relaying with Overhearing

    DEFF Research Database (Denmark)

    Sun, Fan; Kim, Tae Min; Paulraj, Arogyaswami

    2013-01-01

    Carefully designed protocols can turn overheard interference into useful side information to allow simultaneous transmission of multiple communication flows and increase the spectral efficiency in interference-limited regime. In this letter, we propose a novel scheme in a typical cell-edge scenar....... By exploiting the overhearing link through proper relay precoding and adaptive receiver processing, rate performance can be significantly improved compared to the conventional transmission which does not utilize overhearing....

  4. A RVI/LAI-reference curve to detect N stress and guide N fertigation using combined information from spectral reflectance and leaf area measurements in potato

    DEFF Research Database (Denmark)

    Zhenjiang, Zhou; Plauborg, Finn; Thomsen, Anton Gårde

    2017-01-01

    More user-friendly methods are needed to detect crop N status/stress and guide the timing of in-season N application. In the current study, a reference curve method of detecting N stress was proposed to remedy practical problems of methods that require leaf sampling or maintaining a N sufficient...... was applied during the season. The total N ranged from 0 to180 kg N ha−1. RVI and LAI from the economically optimum 180 kg N ha−1 treatments were used to derive the reference curve. RVI and LAI from 180 kg N ha−1 treatment had a high (R2 = 0.97) correlation and were best fitted with a 2nd order polynomial...... function, which was independent of season. The treatments where N fertigation was stopped before reaching 180 kg N ha−1 started to deviate from the 95% confidence interval of the reference curve about 10 days after N-fertigation was stopped. This corresponded to 10–20 kg ha−1 difference in total plant N...

  5. Spectral stability of shifted states on star graphs

    Science.gov (United States)

    Kairzhan, Adilbek; Pelinovsky, Dmitry E.

    2018-03-01

    We consider the nonlinear Schrödinger (NLS) equation with the subcritical power nonlinearity on a star graph consisting of N edges and a single vertex under generalized Kirchhoff boundary conditions. The stationary NLS equation may admit a family of solitary waves parameterized by a translational parameter, which we call the shifted states. The two main examples include (i) the star graph with even N under the classical Kirchhoff boundary conditions and (ii) the star graph with one incoming edge and N  -  1 outgoing edges under a single constraint on coefficients of the generalized Kirchhoff boundary conditions. We obtain the general counting results on the Morse index of the shifted states and apply them to the two examples. In the case of (i), we prove that the shifted states with even N ≥slant 4 are saddle points of the action functional which are spectrally unstable under the NLS flow. In the case of (ii), we prove that the shifted states with the monotone profiles in the N  -  1 edges are spectrally stable, whereas the shifted states with non-monotone profiles in the N  -  1 edges are spectrally unstable, the two families intersect at the half-soliton states which are spectrally stable but nonlinearly unstable under the NLS flow. Since the NLS equation on a star graph with shifted states can be reduced to the homogeneous NLS equation on an infinite line, the spectral instability of shifted states is due to the perturbations breaking this reduction. We give a simple argument suggesting that the spectrally stable shifted states in the case of (ii) are nonlinearly unstable under the NLS flow due to the perturbations breaking the reduction to the homogeneous NLS equation.

  6. CMS kinematic edge from sbottoms

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Peisi; Wagner, Carlos E. M.

    2015-01-01

    We present two scenarios in the Minimal Supersymmetric Extension of the Standard Model (MSSM) that can lead to an explanation of the excess in the invariant mass distribution of two opposite charged, same flavor leptons, and the corresponding edge at an energy of about 78 GeV, recently reported by the CMS Collaboration. In both scenarios, sbottoms are pair produced, and decay to neutralinos and a b-jet. The heavier neutralinos further decay to a pair of leptons and the lightest neutralino through on-shell sleptons or off-shell neutral gauge bosons. These scenarios are consistent with the current limits on the sbottoms, neutralinos, and sleptons. Assuming that the lightest neutralino is stable we discuss the predicted relic density as well as the implications for darkmatter direct detection. We show that consistency between the predicted and the measured value of the muon anomalous magnetic moment may be obtained in both scenarios. Finally, we define the signatures of these models that may be tested at the 13 TeV run of the LHC

  7. Edge instabilities of topological superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Johannes S. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany); Assaad, Fakher F. [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg (Germany); Schnyder, Andreas P. [Max-Planck-Institut fuer Festkoerperforschung, Stuttgart (Germany)

    2016-07-01

    Nodal topological superconductors display zero-energy Majorana flat bands at generic edges. The flatness of these edge bands, which is protected by time-reversal and translation symmetry, gives rise to an extensive ground state degeneracy and a diverging density of states. Therefore, even arbitrarily weak interactions lead to an instability of the flat-band edge states towards time-reversal and translation-symmetry broken phases, which lift the ground-state degeneracy. Here, we employ Monte Carlo simulations combined with mean-field considerations to examine the instabilities of the flat-band edge states of d{sub xy}-wave superconductors. We find that attractive interactions induce a complex s-wave pairing instability together with a density wave instability. Repulsive interactions, on the other hand, lead to ferromagnetism mixed with spin-triplet pairing at the edge. We discuss the implications of our findings for experiments on cuprate high-temperature superconductors.

  8. Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge

    Science.gov (United States)

    Yap, Keng C.

    2010-01-01

    This viewgraph presentation reviews Structural Health Monitoring Analysis for the Orbiter Wing Leading Edge. The Wing Leading Edge Impact Detection System (WLE IDS) and the Impact Analysis Process are also described to monitor WLE debris threats. The contents include: 1) Risk Management via SHM; 2) Hardware Overview; 3) Instrumentation; 4) Sensor Configuration; 5) Debris Hazard Monitoring; 6) Ascent Response Summary; 7) Response Signal; 8) Distribution of Flight Indications; 9) Probabilistic Risk Analysis (PRA); 10) Model Correlation; 11) Impact Tests; 12) Wing Leading Edge Modeling; 13) Ascent Debris PRA Results; and 14) MM/OD PRA Results.

  9. A technique to reduce motion artifact for externally triggered cine-MRI(EC-MRI) based on detecting the onset of the articulated word with spectral analysis

    International Nuclear Information System (INIS)

    Shimada, Yasuhiro; Nishimoto, Hironori; Kochiyama, Takanori; Fujimoto, Ichiro; Mano, Hiroaki; Masaki, Shinobu; Murase, Kenya

    2012-01-01

    One issue in externally triggered cine-magnetic resonance imaging (EC-MRI) for the dynamic observation of speech organs is motion artifact in the phase-encoding direction caused by unstable repetitions of speech during data acquisition. We propose a technique to reduce such artifact by rearranging the k-space data used to reconstruct MR images based on the analysis of recorded speech sounds. We recorded the subject's speech sounds during EC-MRI and used post hoc acoustical processing to reduce scanning noise and detect the onset of each utterance based on analysis of the recorded sounds. We selected each line of k-space from several data acquisition sessions and rearranged them to reconstruct a new series of dynamic MR images according to the analyzed time of utterance onset. Comparative evaluation showed significant reduction in motion artifact signal in the dynamic MR images reconstructed by the proposed method. The quality of the reconstructed images was sufficient to observe the dynamic aspects of speech production mechanisms. (author)